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1
Reis, Geovany Heitor, Marcela de Castro Nunes Santos Terra, David Yue Phin Tng, et al. "Temporal vegetation changes in a seasonally dry tropical forest enclave in an ecotonal region between savanna and semiarid zones of Brazil." Australian Journal of Botany 65, no. 1 (2017): 85. http://dx.doi.org/10.1071/bt16188.
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Seasonally dry tropical forests (SDTFs) comprise a globally significant biome for biodiversity and conservation. Geographically, Brazilian SDTFs are primarily located within the country’s semiarid region (the Caatinga domain) in north-eastern Brazil. However, poorly studied and disjunct SDTF enclaves can occur within other regions, inside other Brazilian phytogeographical domains of vegetation such as savannas (i.e. the Cerrado domain) in central Brazil. These enclaves provide an opportunity to examine natural and non-anthropogenic edge effects on such vegetation. In 2007 and 2014, we studied a 120-ha SDTF enclave in the municipality of Januária in northern Minas Gerais, Brazil, to understand its (1) floristic composition and soil correlates, and (2) temporal variations in diversity, structure and dynamics. Three sets of 10 400-m2 plots were used to compare the vegetation at 0 m (edge), 100 m (middle) and 200 m (inner) into the forest. The edge plots were compositionally dissimilar from the interior plots because of soil fertility and soil textural gradients. Paradoxically also, the inner plots exhibited less stable vegetation-dynamic patterns than did both the middle and the edge plots, possibly owing to natural temporal fluctuations in vegetation dynamics. Overall, the SDTF enclave exhibited high diversity and structural complexity, likely because of its geographical setting within a matrix of savanna. These results highlight a conservation priority for further studies on such SDTF enclaves throughout their range.
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Sutomo and Eddie J. B. van Etten. "Fire Impacts and Dynamics of Seasonally Dry Tropical Forest of East Java, Indonesia." Forests 14, no. 1 (2023): 106. http://dx.doi.org/10.3390/f14010106.
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(1) Background: Seasonally dry tropical forests (SDTFs) are globally important ecosystems which receive less research attention compared to tropical rainforests but are equally under serious threat. The objectives of this paper are to characterize the vegetation structure, diversity and composition of SDTF of Baluran National Park, East Java, Indonesia, and to assess the impact of burning this SDTF and its post-fire recovery. (2) Methods: In the field, we measured floristic composition and dominance at sites with different fire histories in both SDTF and adjacent savannas of Baluran. Remote sensing image analysis was also employed using the MODIS burn area product and various thematic maps. (3) Results: SDTF at Baluran has moderately high tree cover, is less diverse in species than rainforest, and has a prominent vegetative response to fire, especially in the tree layer. The immediate post-fire period in SDTF featured lower densities of tree seedlings and saplings, more grasses and herbs, and lower species richness than older unburned forest. Species composition varied with fire age and vegetation type, with relatively rapid recovery with time since fire evident, although there was some convergence of long-unburned savanna and SDTF sites in terms of floristics. (4) Conclusions: The SDTF of Baluran recovers after fire principally via resprouting but also via seedling regeneration, with structural attributes returning more quickly (<10 years) than floristic composition (>10 years). We did not find consistent evidence of ecosystem transitions between SDTF and savanna despite a small number of long-unburned savanna sites having floristic similarities to dry forest (particularly in terms of characteristic tree species), and we identify the need for more study to determine the degree and mechanisms of forest–savanna transitions in the region, with a future research agenda outlined. Relatively large areas of savanna–dry forest transitions demonstrated from remote sensing analyses were primarily attributed to spread of Acacia nilotica (an alien invasive small tree or shrub) into long-unburned savanna, and its decline in areas where the species is being successfully controlled via burning and cutting. Knowledge of such ecological shifting is important for the ecosystem management, especially in terms of their usage by large mammals.
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Marcelo-Peña, J. L., I. Huamantupa, T. Särkinen, and M. Tomazello. "IDENTIFYING CONSERVATION PRIORITY AREAS IN THE MARAÑÓN VALLEY (PERU) BASED ON FLORISTIC INVENTORIES." Edinburgh Journal of Botany 73, no. 1 (2015): 95–123. http://dx.doi.org/10.1017/s0960428615000281.
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In this study, we report species diversity and endemism of the poorly known but highly diverse Seasonally Dry Tropical Forest (SDTF) flora of the Marañón valley in northern Peru. We characterise woody vascular plant species diversity across the valley in order to define the conservation value of the area at national and international level. Based on 32 rapid botanical inventories, 92 plots of 50 × 20 m, and a herbarium study across local and international herbaria, we report 440 woody vascular plant species of which 143 (33%) are endemic to the valley. Two centres of endemism within the valley are identified, each with clear elevational zonation of diversity. Data show that the Marañón valley is a good representative of Peruvian SDTFs as a whole, with an average of 56% SDTF species and 78% SDTF genera found in the one valley. The results show that there is wide variation in the set of dominant species across the valley, and that many local endemics are locally abundant unlike in neighbouring SDTFs where the dominant species are all geographically widespread. Our results demonstrate that the Marañón includes a rare combination of both nationally representative yet globally unique plant species, which makes the valley an ideal conservation target. The high level of endemism structured within elevational zones implies that conservation areas should be established across elevational zones in order to maximise the protection of this globally unique flora.
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Bueno, M. L., D. R. Neves, A. T. Oliveira Filho, C. R. Lehn, and J. A. Ratter. "A STUDY IN AN AREA OF TRANSITION BETWEEN SEASONALLY DRY TROPICAL FOREST AND MESOTROPHIC CERRADÃO, IN MATO GROSSO DO SUL, SOUTHWESTERN BRAZIL." Edinburgh Journal of Botany 70, no. 3 (2013): 469–86. http://dx.doi.org/10.1017/s0960428613000164.
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This study describes the tree vegetation and soils occurring in a seasonally dry tropical forest (SDTF) and mesotrophic cerradão transition in southwestern Brazil. All trees ≥ 5 cm diameter were measured in 20 plots of 20 × 25 m, 10 in SDTF, and 10 in mesotrophic cerradão. Ten soil samples of 0−20 cm depth were made per plot and mixed in plot groups to produce two composite samples. A total of 71 species was recorded.Anadenanthera colubrinahad the highest importance values in both formations. Differences in soil fertility were found between SDTFs (eutrophic soils) and mesotrophic cerradão (mesotrophic soils). A non-metric multidimensional scaling and cluster analysis confirmed the soil fertility segregation, and also showed an agreement between soil fertility and variance in species composition gradients. The mesotrophic cerradão showed higher species richness since it also includes many species typical of more dystrophic and open forms of Cerrado.
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Power, M. J., B. S. Whitney, F. E. Mayle, D. M. Neves, E. J. de Boer, and K. S. Maclean. "Fire, climate and vegetation linkages in the Bolivian Chiquitano seasonally dry tropical forest." Philosophical Transactions of the Royal Society B: Biological Sciences 371, no. 1696 (2016): 20150165. http://dx.doi.org/10.1098/rstb.2015.0165.
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South American seasonally dry tropical forests (SDTFs) are critically endangered, with only a small proportion of their original distribution remaining. This paper presents a 12 000 year reconstruction of climate change, fire and vegetation dynamics in the Bolivian Chiquitano SDTF, based upon pollen and charcoal analysis, to examine the resilience of this ecosystem to drought and fire. Our analysis demonstrates a complex relationship between climate, fire and floristic composition over multi-millennial time scales, and reveals that moisture variability is the dominant control upon community turnover in this ecosystem. Maximum drought during the Early Holocene, consistent with regional drought reconstructions, correlates with a period of significant fire activity between 8000 and 7000 cal yr BP which resulted in a decrease in SDTF diversity. As fire activity declined but severe regional droughts persisted through the Middle Holocene, SDTFs, including Anadenanthera and Astronium , became firmly established in the Bolivian lowlands. The trend of decreasing fire activity during the last two millennia promotes the idea among forest ecologists that SDTFs are threatened by fire. Our analysis shows that the Chiquitano seasonally dry biome has been more resilient to Holocene changes in climate and fire regime than previously assumed, but raises questions over whether this resilience will continue in the future under increased temperatures and drought coupled with a higher frequency anthropogenic fire regime. This article is part of the themed issue ‘The interaction of fire and mankind’.
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Nakade, Yukiomi, Rena Kitano, Kazumasa Sakamoto, et al. "Characteristics of bile acid composition in high fat diet-induced nonalcoholic fatty liver disease in obese diabetic rats." PLOS ONE 16, no. 2 (2021): e0247303. http://dx.doi.org/10.1371/journal.pone.0247303.
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Bile acid has attracted attention as a signal transmission molecule in energy metabolism. Although a high-fat diet (HFD) or obesity is known to increase hepatic fat content and alter bile acid composition, the changes in bile acid composition due to HFD or obesity remain to be elucidated. We sought to examine the bile acid composition in high fat diet-induced non-alcoholic fatty liver disease (NAFLD) in obese diabetic rats. Eight-week-old male spontaneously diabetic Torii fatty (SDTF) rats or control rats were fed an HFD. Twelve weeks post the commencement of HFD, serum and hepatic bile acid compositions and serum GLP-1 levels, which is stimulated by the secondary bile acid deoxycholic acid (DCA), were measured. The correlation between the bile acid composition and serum GLP-1 levels was also examined. While serum and hepatic levels of cholic acid (CA), a primary bile acid, tended to decrease in HFD-fed control rats, they were significantly decreased in HFD-fed SDTF rats. Hepatic CYP8B1, which plays a role in CA synthesis, the mRNA levels were significantly decreased in HFD-fed control and SDTF rats. In contrast, while serum and hepatic DCA levels were not changed in HFD-fed control rats, they were decreased in HFD-fed SDTF rats. Hepatic DCA/CA did not change in HFD-fed SDTF rats, but significantly increased in HFD-fed control rats. While serum GLP-1 levels were not changed in SDTF rats, they were significantly increased in HFD-fed control rats. Hepatic DCA/CA tended to correlate with serum GLP-1 levels, which tended to negatively correlate with the hepatic triglyceride content in SDTF rats. These results indicate that relatively increased DCA might contribute to an increase in serum GLP-1 levels, which inhibits hepatic steatosis in NAFLD.
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Majure, Lucas C., Serena Achá, Marc A. Baker, Raul Puente-Martínez, Matias Köhler, and Shannon Fehlberg. "Phylogenomics of One of the World’s Most Intriguing Groups of CAM Plants, the Opuntioids (Opuntioideae: Cactaceae): Adaptation to Tropical Dry Forests Helped Drive Prominent Morphological Features in the Clade." Diversity 15, no. 4 (2023): 570. http://dx.doi.org/10.3390/d15040570.
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Opuntioideae, composed of roughly 370 species, occur in almost every biome in the Americas, from seasonally dry tropical forests (SDTF) to high-elevation Andean grasslands, American deserts and temperate zones. The interrelationships among the three major clades of Opuntioideae (Cylindropuntieae, Opuntieae and Tephrocacteae) are not well resolved, and thus, the ancestral habitat, biogeographic history and evolution of morphological characters, such as large photosynthetic leaves and flattened stems, are poorly understood. To test their geographic origin and evolution of key morphological characters, we built the largest phylogenomic dataset for Cactaceae to date using 103 plastid genes of 107 taxa of Opuntioideae. The subfamily Opuntioideae likely evolved in South America in a combination of seasonally dry tropical forest (SDTF)/desert habitats. Opuntieae most likely evolved in South America in SDTF and, from there, moved into desert regions, Chaco and temperate/subtropical zones, while Tephrocacteae and Cylindropuntieae evolved in South America in desert regions and moved into SDTF, Chaco and temperate/subtropical zones. Analyses of morphological evolution suggest that, although large leaves are plesiomorphic in Opuntioideae, long-lived, photosynthetically active leaves in Cylindropuntieae and Tephrocacteae are homoplasious and do not represent retained plesiomorphy, as is often assumed. Flattened stems are synapomorphic for Opuntieae, possibly representing adaptation to competition for light resources in SDTF, their most likely ancestral area.
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Rodrigues, PMS, JO Silva, PV Eisenlohr, and CEGR Schaefer. "Climate change effects on the geographic distribution of specialist tree species of the Brazilian tropical dry forests." Brazilian Journal of Biology 75, no. 3 (2015): 679–84. http://dx.doi.org/10.1590/1519-6984.20913.
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AbstractThe aim of this study was to evaluate the ecological niche models (ENMs) for three specialist trees (Anadenantheracolubrina, Aspidosperma pyrifolium and Myracrodruon urundeuva) in seasonally dry tropical forests (SDTFs) in Brazil, considering present and future pessimist scenarios (2080) of climate change. These three species exhibit typical deciduousness and are widely distributed by SDTF in South America, being important in studies of the historical and evolutionary processes experienced by this ecosystem. The modeling of the potential geographic distribution of species was done by the method of maximum entropy (Maxent).We verified a general expansion of suitable areas for occurrence of the three species in future (c.a., 18%), although there was reduction of areas with high environmental suitability in Caatinga region. Precipitation of wettest quarter and temperature seasonality were the predictor variables that most contributed to our models. Climatic changes can provide more severe and longer dry season with increasing temperature and tree mortality in tropics. On this scenario, areas currently occupied by rainforest and savannas could become more suitable for occurrence of the SDTF specialist trees, whereas regions occupied by Caatinga could not support the future level of unsustainable (e.g., aridity). Long-term multidisciplinary studies are necessary to make reliable predictions of the plant’s adaptation strategies and responses to climate changes in dry forest at community level. Based on the high deforestation rate, endemism and threat, public policies to minimize the effects of climate change on the biodiversity found within SDTFs must be undertaken rapidly.
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Londoño-Lemos, Viviana, Alba Marina Torres-Gonzáles, and Santiago Madriñán. "Linking Seed Traits and Germination Responses in Caribbean Seasonally Dry Tropical Forest Species." Plants 13, no. 10 (2024): 1318. http://dx.doi.org/10.3390/plants13101318.
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Understanding the relationships between seed traits and germination responses is crucial for assessing natural regeneration, particularly in threatened ecosystems like the seasonally dry tropical forest (SDTF). This study explored links between seed traits (mass, volume, moisture content, and dispersal type), germination responses (germinability, germination speed (v¯), time to 50% of germination (T50), synchrony, and photoblastism), and physical dormancy (PY) in 65 SDTF species under experimental laboratory conditions. We found that species with smaller seeds (low mass and volume) had higher v¯ and reached T50 faster than species with larger seeds. For moisture content, species with lower moisture content had higher germinability and reached the T50 faster than seeds with high moisture content. Abiotic dispersed species germinated faster and reached the T50 in fewer days. Most of the SDTF species (60%) did not present PY, and the presence of PY was associated with seeds with lower moisture content. As for photoblastism (germination sensitivity to light), we classified the species into three ecological categories: generalists (42 species, non-photoblastic), heliophytes (18 species, positive photoblastic, germination inhibited by darkness), and sciadophytes (5 species, negative photoblastic, light inhibited germination). This study intends to be a baseline for the study of seed ecophysiology in the SDTF.
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Apgaua, Deborah Mattos Guimarães, Polyanne Aparecida Coelho, Rubens Manoel dos Santos, Paola Ferreira Santos, and Ary Teixeira de Oliveira-Filho. "Tree community structure in a seasonally dry tropical forest remnant, Brazil." CERNE 20, no. 2 (2014): 173–82. http://dx.doi.org/10.1590/01047760.201420021540.
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Most studies on Seasonally Dry Tropical Forests (SDTFs) investigate phytogeographic patterns and floristic connections of this disjunct biome. However, little is known about the structural characteristics of SDTFs. We aimed to describe the structure of a SDTF in an ecotonal area between the Cerrado and Caatinga domains. In total, 79 tree species were recorded, and high values of Shannon diversity index (3.6 nats/individual) and equability (0.83) were observed. The diameter distribution for the species with higher cover values and for the entire community did not exhibit a reverse-J shaped distribution, which indicates the occurrence of different growth strategies and ecological adaptations to water stress. The results did not indicate the formation of floristic groups, as the high soil fertility in the study area results in a homogeneous environment. The structural characteristics of the study area associated with the soil composition highlight its importance for conservation and emphasize the need for community structure studies in SDTFs.
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Kuś*, Rafał, Katarzyna Blinowska, Maciej Kamiński, and Anna Basińska-Starzycka. "Transmission of information during Continuous Attention Test." Acta Neurobiologiae Experimentalis 68, no. 1 (2008): 103–12. http://dx.doi.org/10.55782/ane-2008-1678.
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The Short-Time Directed Transfer Function (SDTF) is an estimator based on a multivariate autoregressive model which has proved to be successful in ERP experiments, e.g. those connected with motor action and its imagination. The aim of this study is the evaluation of the performance of SDTF in the cognitive experiment. We have applied SDTF for the estimation of the pattern of EEG signal transmissions during a Continuous Attention Test (CAT). Time-frequency patterns of propagation were estimated for two experimental conditions. Statistical procedures based on thin-plate spline model were used for estimation of significant changes in respect to the reference epoch. The repeatability of the results for a subject and across the subjects were investigated. The effect of prolonged transmission in the gamma band from the prefrontal electrodes found in all subjects was explained by the active inhibition in the case when a subject had to sustain from performing the action.
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Rocha, Andre Medeiros, Marcos Esdras Leite, and Mário Marcos do Espírito-Santo. "MONITORING OF BRAZILIAN DECIDUOUS SEASONAL FOREST BY REMOTE SENSING." Mercator 19, no. 2020 (2020): 1–20. http://dx.doi.org/10.4215/rm2020.e19022.
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Among the many characteristics that the Brazilian territory possesses, one precisely excel: the mentioned country hosts the second biggest forest resource of the planet, corresponding for approximately 10% of the total amount of global forest resources. In that scenario, the Seasonally Dry Tropical Forests (SDTF) perform the second less expressive forest type in Brazil, being situated mostly in non-forested biomes, such as Savannas and Scrublands. Thus, its conservation must rely on its correct identification, which becomes difficult because the SDTF areas are generally classified as other vegetation types. Therefore, the present study aimed to perform the land cover-land use monitoring for the years of 2007 and 2016 of the continuous area North of Minas Gerais - South Piauí, with the purpose of evaluating the current situation of Brazilian SDTFs and assessing the main drivers that affect its deforestation and natural regeneration. As a result, the study verified that the significant increase in crop areas and spatial mobility of parturelands contributed decisively for the changes presented by vegetation formations. HOWEVER, such drivers played differentiated roles in losses/gains. Especially, it was concluded that the changes in which deciduous forests have undergone were explained particularly by pasture. The other types of vegetation were also impacted by this class, but with a more incisive participation of the crops. Key-words: Mapping, Deciduous Forests, Remote Sensing, GIS.
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Valle, Darwin, Daniel M. Griffith, Andrea Jara-Guerrero, Diego Armijos-Ojeda, and Carlos I. Espinosa. "A multifaceted approach to understanding bat community response to disturbance in a seasonally dry tropical forest." Scientific Reports 11, no. 1 (2021): 5667. https://doi.org/10.5281/zenodo.14818896.
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(Uploaded by Plazi for the Bat Literature Project) Abstract Given widespread habitat degradation and loss, reliable indicators are needed that provide a comprehensive assessment of community response to anthropogenic disturbance. The family Phyllostomidae (Order Chiroptera) has frequently been the focus of research evaluating bats' response to habitat disturbance in seasonally dry tropical forests (SDTFs). However, few studies compare this family to the larger bat assemblage to assess its efficacy as a bioindicator. We compared community and species-specific attributes of understory phyllostomid and all understory bat species: (1) along a gradient of habitat disturbance within a human-modified SDTF landscape; and (2) between forest and riparian habitats within each disturbance level. We captured 290 individuals belonging to 13 species and 4 families. Phyllostomid species exhibited greater sensitivity to disturbance than the understory bat community as a whole based on richness and beta diversity. Both groups were more sensitive to disturbance in forest than riparian habitat, but phyllostomid species were more likely to be lost from highly disturbed forest habitat. The two dominant species declined in abundance with disturbance but variation in body condition was species-specific. These results suggest that Phyllostomidae are more effective indicators of human disturbance in SDTF than the understory bat community as a whole and evaluation of bats' response to disturbance is best accomplished with a multifaceted approach.
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ANDRADE, EUNICE MAIA DE, GILBERTO QUEVEDO ROSA, ALDENIA MENDES MASCENA DE ALMEIDA, ANTONIO GIVANILSON RODRIGUES DA SILVA, and MARIA GINA TORRES SENA. "RAINFALL REGIME ON FINE ROOT GROWTH IN A SEASONALLY DRY TROPICAL FOREST." Revista Caatinga 33, no. 2 (2020): 458–69. http://dx.doi.org/10.1590/1983-21252020v33n218rc.
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ABSTRACT Seasonally dry tropical forests (SDTF) usually present dry seasons of eight or more months. Considering the concerns about the resilience of SDTF to climate changes, the objective of this study was to evaluate the effect of the rainfall regime on fine root growth in a SDTF. The experiment started at the end of the wet season (July 2015), when fine roots were evaluated and ingrowth cores were implemented. The temporal growth of fine roots in the 0-30 cm soil layer was monitored, considering the 0-10, 10-20, and 20-30 cm sublayers, through six samplings from November 2015 to July 2017. The characteristics evaluated were fine root biomass, fine root length, fine root specific length, and fine root mean diameter. The significances of the root growths over time and space were tested by the Kruskal-Wallis test (p<0.05). Fine roots (Ø<2 mm) were separated and dried in an oven (65 °C) until constant weight. The root length was determined using the Giaroots software. The fine root biomass in July 2015 was 7.7±5.0 Mg ha-1 and the length was 5.0±3.2 km m-2. Fine root growth in SDTF is strongly limited by dry periods, occurring decreases in biomass and length of fine roots in all layers evaluated. Fine root growth occurs predominantly in rainy seasons, with fast response of the root system to rainfall events, mainly in root length.
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Zhang, Dawn X., and Christopher K. Glass. "Towards an understanding of cell-specific functions of signal-dependent transcription factors." Journal of Molecular Endocrinology 51, no. 3 (2013): T37—T50. http://dx.doi.org/10.1530/jme-13-0216.
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The ability to regulate gene expression in a cell-specific manner is a feature of many broadly expressed signal-dependent transcription factors (SDTFs), including nuclear hormone receptors and transcription factors that are activated by cell surface receptors for extracellular signals. As the most plastic cells of the hematopoietic system, macrophages are responsive to a wide spectrum of regulatory molecules and provide a robust model system for investigation of the basis for cell-specific transcriptional responses at a genome-wide level. Here, focusing on recent studies in macrophages, we review the evidence suggesting a model in which cell-specific actions of SDTFs are the consequence of priming functions of lineage determining transcription factors. We also discuss recent findings relating lineage-determining and SDTF activity to alterations in the epigenetic landscape as well as the production and function of enhancer RNAs. These findings have implications for the understanding of how natural genetic variation impacts cell-specific programs of gene expression and suggest new approaches for altering gene expressionin vivo.
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Esquerre-Ibañez, Boris, Guillermo E. Delgado-Paredes, Consuelo Rojas-Idrogo, Cecilia Vásquez-Díaz, and J. R. Kuethe. "Micropropagation and Germplasm Conservation of Ficus americana Aubl. and F. obtusifolia Kunth from Lambayeque (Peru)." Colombia forestal 26, no. 1 (2022): 92–108. http://dx.doi.org/10.14483/2256201x.19114.
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Ficus americana and F. obtusifolia are among the most important tree species in Seasonally Dry Tropical Forests (SDTF) due to their evergreen condition and high levels of biomass. However, the SDTF of Lambayeque and northern Peru is greatly diminishing due to the advance of migratory agriculture, illegal mining, and deforestation. The objective of this work was to study the taxonomic aspects of both species, as well as seed germination, micropropagation, and in vitro germplasm conservation. Seed germination was 100% for both species up to three months after collection. As for micropropagation, rooting, and germplasm conservation, the Piper culture medium was effective, as it was constituted by MS mineral salts with 0.02 mg.L-1 IAA and 0.02 mg.L-1 GA3. In vitro germplasm conservation lasted more than 24 months for both species. Acclimatization under greenhouse conditions reached 50% survival for both species.
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Bolaños-Rojas, Ana C., Jorge M. Londoño-Caicedo, Andrés J. Cortés, and Viviana Motato-Vásquez. "Phylogenetic Diversity, Host Specificity, and Distribution of the Wood-Decaying Fungus Phellinotus teixeirae in Western Colombia’s Seasonally Dry Tropical Forest." Forests 15, no. 6 (2024): 1008. http://dx.doi.org/10.3390/f15061008.
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Phellinotus (Polyporales) is a common genus of wood-decay fungi in tropical and subtropical areas, endemic to the Seasonally Dry Tropical Forest (SDTF) biome. However, Phellinotus diversity remains unexplored, despite being a major threat to living trees. Therefore, this study is aimed at confirming and characterizing through morphological and molecular data the first isolates of Phellinotus teixeirae in Pithecellobium dulce (Fabaceae) trees (locally referred to as ‘Chiminango’) from the endangered Colombian SDTF biome. Fifteen fungal specimens were recovered from living P. dulce trees, in the urban area and at the Universidad del Valle campus, and classified as P. teixeirae based on taxonomical descriptors. Phylogenetic relationships were inferred from a four-loci dataset (ribosomal and gene-coding regions), including 82 taxa covering 3991 nucleotide positions. The analysis recovered seven highly supported (>90% bootstrapping) monophyletic taxa of the ‘Phellinotus Clade’, and confirmed the new distribution range of P. teixeirae (100% bootstrap support), which extends approx. 1000 km north in the Neotropics. Hierarchical stratified Analysis of MOlecular VAriance (AMOVA) provided a clear genetic distinction between species (70% of variation, p-value = 0.001) and low differentiation among country of origin within species (11%, p-value = 0.044). Discriminant Analysis for Principal Components (DAPC) indicated complex clustering including closely related species, probably a signal of recent radiation and weak species boundaries. Median-joining haplotype network analysis identified unique haplotypes, which may correlate with new host colonization and population expansion (Tajima’s D ≤ −0.5). In conclusion, this study provides the first assessment of the genetic diversity of P. teixeirae in a novel geography (SDTP) and host tree (P. dulce). However, increasing the number of isolates remains critical to understand further the genus’ distribution patterns and drivers of genetic diversity.
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Yavuz Temel, Güler. "A Simulation and Empirical Study of Differential Test Functioning (DTF)." Psych 5, no. 2 (2023): 478–96. http://dx.doi.org/10.3390/psych5020032.
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Detecting and understanding DTF is very important under various DIF conditions. In this study, the performance of DTF, DRF, SIBTEST, and CSIBTEST approaches in detecting DIF effects was investigated using a simulation study and a real dataset. It was observed that different DIF conditions (uniform, non-uniform), the proportion of DIF items in the test, the DIF size, and the DIF effect (balanced, unbalanced) affected the performance of the methods, and especially in the case of the non-uniform DIF condition, the power rates of sDTF, sDRF, and SIBTEST statistics were low. In addition, according to the DTF estimations with the balanced/unbalanced DIF effect condition, in some cases, the effect of DIF on the overall test could be negligible. However, it was clearly emphasized in this study that DTF analyses should accompany DIF studies since DTF analysis may change with different DIF and test conditions.
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Flores-Tolentino, Mayra, Leonardo Beltrán-Rodríguez, Jonas Morales-Linares, et al. "Biogeographic regionalization by spatial and environmental components: Numerical proposal." PLOS ONE 16, no. 6 (2021): e0253152. http://dx.doi.org/10.1371/journal.pone.0253152.
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Regionalization through the analysis of species groups offers important advantages in conservation biology, compared to the single taxon approach in areas of high species richness. We use a systematic framework for biogeographic regionalization at a regional scale based on species turnover and environmental drivers (climate variables and soil properties) mainly of herbaceous plant species richness. To identify phytogeographic regions in the Balsas Depression (BD), we use Asteraceae species, a family widely distributed in Seasonally Dry Tropical Forest (SDTF) and the most diverse of the vascular plants in Mexico. Occurrence records of 571 species were used to apply a quantitative analysis based on the species turnover, the rate of changes in their composition between sites (β-Simpson index) and the analysis of the identified environmental drivers. Also, the environmental predictors that influence species richness in the SDTF were determined with a redundancy analysis. We identified and named two phytogeographic districts within the SDTF of the BD (Upper Balsas and Lower Balsas). According to the multi-response permutation procedure, floristic composition of the two districts differs significantly, and the richness of exclusive species in Upper Balsas was higher (292 species) than in the Lower Balsas (32 species). The proportion of Mg and Ca in the soil and the precipitation of the driest three-month period were the environmental factors with greatest positive influence on species richness. The division of geographic districts subordinated to the province level, based on diverse families such as Asteraceae, proved to be appropriate to set up strategies for the conservation of the regional flora, since at this scale, variation in species richness is more evident. Our findings are consistent with a growing body of biogeographic literature that indicates that the identification of smaller biotic districts is more efficient for the conservation of biodiversity, particularly of endemic or rare plants, whose distribution responds more to microhabitats variation.
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HUAMÁN-MERA, ALEXANDER, YURIKO SUMIYO MURILLO-DOMEN, DANNA Z. AMAYA-REYES, FLOR Y. SAUCEDO-BURGA, PEDRO MANUEL VILLA, and LEOPOLDO P. VÁSQUEZ-NÚÑEZ. "Update of the taxonomic circumscription and biogeographical delimitation range of Neltuma pallida (Fabaceae) to the Seasonally Dry Forests of Marañon from Peru." Phytotaxa 691, no. 1 (2025): 1–18. https://doi.org/10.11646/phytotaxa.691.1.1.
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Several specimens collected along Seasonally Dry Tropical Forests (SDTF) from Peru have been named as Neltuma pallida (Prosopis pallida before); however, morphological and ecological traits are different among these specimens. The update of the taxonomic circumscription and biogeographical delimitation of N. pallida are presented here based on morphological characteristics and Species Distribution Modeling (SDM) based on the principle of Maximum Entropy and 19 bioclimatic variables from historical data. 262 specimens distributed along the SDTF were morphologically evaluated, and 62 specimens corresponded to N. pallida according to the initial taxonomic description. Historical habitat suitability analyses (SDM) revealed significant geographic distribution shifts for N. pallida across climatic periods, highlighting expansions during the Last Glacial Maximum and contractions in subsequent interglacial periods restricted to the Seasonally Dry Forests of Marañon (SDFM). These findings suggest that the SDFM may have provided ecological refugia for N. pallida, allowing it to endure climatic fluctuations over millennia. Thus, only Neltuma populations distributed along SDFM must be named Neltuma pallida due to evident unique morphological characteristics and biogeographic restrictions across time.
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Maia Andrade, Eunice, Wilner Valbrun, Aldênia Mendes Mascena de Almeida, Gilberto Rosa, and Antonio Givanilson Rodrigues da Silva. "Land-Use Effect on Soil Carbon and Nitrogen Stock in a Seasonally Dry Tropical Forest." Agronomy 10, no. 2 (2020): 158. http://dx.doi.org/10.3390/agronomy10020158.
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Total organic carbon (TOC) and total nitrogen (TN) concentration in the soil are an indicator of soil degradation. To understand how land-use may impact these concentrations in seasonally dry tropical forests (SDTF), we analyzed the effect of four land-uses on TOC stocks (STK.TOC) and TN stocks (STK.TN) in a semi-arid region of Brazil. Soil samples were collected in 12 trenches (three sites × four land-uses—dense caatinga (DC), open caatinga (OC), pasture (PA) and agriculture (AG)), in the 0–10; 10–20 and 20–30 cm layers or as far as the bedrock. The data were compared by the Kruskal–Wallis test (p ≤ 0.05) and similarity investigated by cluster analysis. STK.TOC and STK.TN the surface layer (0–10 cm) showed no significant difference (p ≤ 0.05) between the DC; OC and PA land-uses. The similarity in STK.TOC and STK.TN values between DC, OC and PA, indicate that it is possible to explore SDTF to produce biomass and protein by adopting open caatinga and pasture land uses on Neosols with very low TOC stocks. The greatest reduction in STK.TOC and STK.TN in the agriculture land-use may lead to soil degradation and contribute to the addition of CO2 to the atmosphere.
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Kaminski, Maciej, Aneta Brzezicka, Jan Kaminski, and Katarzyna J. Blinowska. "Coupling Between Brain Structures During Visual and Auditory Working Memory Tasks." International Journal of Neural Systems 29, no. 03 (2019): 1850046. http://dx.doi.org/10.1142/s0129065718500466.
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Transmission of EEG activity during a visual and auditory version of the working memory task based on the paradigm of linear syllogism was investigated. Our aim was to find possible similarities and differences in the synchronization patterns between brain structures during the same mental activity performed on different modality stimuli. The EEG activity transmission was evaluated by means of full frequency Directed Transfer Function (ffDTF) and short-time Directed Transfer Function (SDTF). SDTF provided information on dynamical propagation of EEG activity. The assortative mixing approach was applied to quantify coupling between regions of interest encompassing frontal, central and two posterior modules. The results showed similar schemes of coupling for both modalities with stronger coupling within the regions of interests than between them, which is concordant with the theories concerning efficient wiring and metabolic energy saving. The patterns of transmission showed main sources of activity in the anterior and posterior regions communicating intermittently in a broad frequency range. The differences between the patterns of transmission between the visual and auditory versions of working memory tasks were subtle and involved bigger propagation from the posterior electrodes towards the frontal ones during the visual task as well as from the temporal sites to the frontal ones during the auditory task.
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Lucas, Fernanda Moura Fonseca, Kyvia Pontes Teixeira das Chagas, Ageu da Silva Monteiro Freire, Vivian Raquel Bezerra de Sousa, and Fábio de Almeida Vieira. "Phenological strategies of an evergreen tree in the Caatinga." PLOS ONE 20, no. 3 (2025): e0317522. https://doi.org/10.1371/journal.pone.0317522.
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Seasonally Dry Tropical Forests (SDTF) account for 40% of global tropical forests, with the Caatinga standing out as the largest continuous formation of this type. However, the region faces severe threats, such as deforestation and desertification, which require urgent conservation efforts. In this context, understanding the adaptive strategies of native species becomes essential to support management actions. This study aims to identify the phenological strategies of Sarcomphalus joazeiro (Mart.), a species of high ecological, cultural, and economic importance in the region. Over two years, intrapopulation monitoring of vegetative and reproductive phenophases was conducted in a forest fragment in Rio Grande do Norte, Brazil, evaluating phenophase seasonality, reproductive synchrony, correlation with meteorological variables (precipitation, relative humidity, and air temperature), and fruit and seed biometrics. The results revealed that the flowering and fruiting of S. joazeiro are annual, synchronized, and occur during the dry season, highlighting an adaptive reproductive strategy and providing an important food source for the fauna. The species exhibited a weak correlation between its phenophases and meteorological variables, emphasizing its resistance to adverse climatic conditions. These characteristics make S. joazeiro unique among SDTF trees and underscore its ecological importance and potential for management and degraded area restoration strategies. Phenological studies with other Caatinga species are recommended to deepen understanding of biota-climate interactions and to contribute to effective conservation strategies.
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Valbrun, W., E. M. de Andrade, A. M. M. de Almeida, and E. L. de Almeida. "Carbon and Nitrogen Stock Under Different Types of Land Use in a Seasonally Dry Tropical Forest." Journal of Agricultural Science 10, no. 12 (2018): 479. http://dx.doi.org/10.5539/jas.v10n12p479.
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The aim of this study, was to analyse the effect of cover vegetation change on stocks of Total Organic Carbon (ST.TOC) and Total Nitrogen (ST.TN) in soils of a Seasonally Dry Tropical Forest in the Brazilian semi-arid region. The study was carried out on three farms located on a typical Orthic Chromic Luvisol in an SDTF. Soil samples were collected from trenches, 70 &times; 70 cm in size, in the 0-10, 10-20, 20-30, 30-40, 40-60 and 60-80 cm layers, under four types of land use: dense Caatinga (DC), open Caatinga (OC), agriculture (AG) and pasture (PA). The following attributes were evaluated: bulk density, Total Organic Carbon (TOC), Total Nitrogen (TN), ST.TOC and ST.TN. The data were compared using the Mann-Whitney test (p &le; 0.05). Hierarchical Grouping Analysis (HGA) was used to understand the behaviour of the attributes evaluated between cover vegetation types. Using HGA resulted in the formation of three distinct groups for the types of land use under investigation. The highest mean values for ST.TOC (11.29 Mg ha-1) and ST.TN (3.36 Mg ha-1) were found in CD and CA. The changes in land use in the SDTF had an effect on ST.TOC and ST.TN. It is therefore necessary to adopt strategies and strengthen conservation practices in areas of agricultural and pasture, and reduce the process of degradation and further the process of recovery in these areas. Such action will reduce the loss of C and N, and increase the levels and stocks of TOC and TN.
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Ferreira, Maria Beatriz, Rinaldo Luiz Caraciolo Ferreira, Jose Antonio Aleixo da Silva, et al. "Spatial-Temporal Dynamics of Water Resources in Seasonally Dry Tropical Forest: Causes and Vegetation Response." AgriEngineering 6, no. 3 (2024): 2526–52. http://dx.doi.org/10.3390/agriengineering6030148.
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Seasonally Dry Tropical Forests (SDTFs) are situated in regions prone to significant water deficits. This study aimed to evaluate and quantify the dynamics and spatial patterns of vegetation and water bodies through the analysis of physical–hydrological indices for a remnant of FTSD between 2013 and 2021. Basal area, biomass, and tree number were monitored in 80 permanent plots located in two areas of an SDTF remnant with different usage histories. To assess vegetation and water resource conditions, geospatial parameters NDVI, NDWIveg, NDWI, and MNDWI were estimated for the period from 2013 to 2021. The observed patterns were evaluated by simple linear regression, principal component analysis (PCA), and principal component regression (PCR). Area 2 presented higher values of basal area, biomass, and number of trees. In area 1, there was an annual increase in basal area and biomass, even during drought years. The NDVI and NDWIveg indicated the vulnerability of vegetation to the effects of droughts, with higher values recorded in 2020. NDWI and MNDWI detected the water availability pattern in the study area. Physical–hydrological indices in the dynamics of tree vegetation in dry forests are influenced by various factors, including disturbances, soil characteristics, and precipitation patterns. However, their predictive capacity for basal area, biomass, and tree number is limited, highlighting the importance of future research incorporating seasonal variability and specific local conditions into their analyses.
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Saenz-Pedroza, Irving, Richard Feldman, Casandra Reyes-García, et al. "Seasonal and successional dynamics of size-dependent plant demographic rates in a tropical dry forest." PeerJ 8 (September 14, 2020): e9636. http://dx.doi.org/10.7717/peerj.9636.
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Tropical forests are globally important for biodiversity conservation and climate change mitigation but are being converted to other land uses. Conversion of seasonally dry tropical forests (SDTF) is particularly high while their protection is low. Secondary succession allows forests to recover their structure, diversity and composition after conversion and subsequent abandonment and is influenced by demographic rates of the constituent species. However, how these rates vary between seasons for different plant sizes at different successional stages in SDTF is not known. The effect of seasonal drought may be more severe early in succession, when temperature and radiation are high, while competition and density-dependent processes may be more important at later stages, when vegetation is tall and dense. Besides, the effects of seasonality and successional stage may vary with plant size. Large plants can better compete with small plants for limiting resources and may also have a greater capacity to withstand stress. We asked how size-dependent density, species density, recruitment and mortality varied between seasons and successional stages in a SDTF. We monitored a chronosequence in Yucatan, Mexico, over six years in three 0.1 ha plots in each of three successional stages: early (3–5 years-old), intermediate (18–20 years-old) and advanced (>50 years-old). Recruitment, mortality and species gain and loss rates were calculated from wet and dry season censuses separately for large (diameter > 5 cm) and small (1–5 cm in diameter) plants. We used linear mixed-effects models to assess the effects of successional stage, seasonality and their changes through time on demographic rates and on plant and species density. Seasonality affected demographic rates and density of large plants, which exhibited high wet-season recruitment and species gain rates at the early stage and high wet-season mortality at the intermediate stage, resulting in an increase in plant and species density early in succession followed by a subsequent stabilization. Small plant density decreased steadily after only 5 years of land abandonment, whereas species density increased with successional stage. A decline in species dominance may be responsible for these contrasting patterns. Seasonality, successional stage and their changes through time had a stronger influence on large plants, likely because of large among-plot variation of small plants. Notwithstanding the short duration of our study, our results suggest that climate-change driven decreases in rainy season precipitation may have an influence on successional dynamics in our study forest as strong as, or even stronger than, prolonged or severe droughts during the dry season.
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Sesnie, Steven E., Carlos I. Espinosa, Andrea K. Jara-Guerrero, and María F. Tapia-Armijos. "Ensemble Machine Learning for Mapping Tree Species Alpha-Diversity Using Multi-Source Satellite Data in an Ecuadorian Seasonally Dry Forest." Remote Sensing 15, no. 3 (2023): 583. http://dx.doi.org/10.3390/rs15030583.
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The increased variety of satellite remote sensing platforms creates opportunities for estimating tropical forest diversity needed for environmental decision-making. As little as 10% of the original seasonally dry tropical forest (SDTF) remains for Ecuador, Peru, and Colombia. Remnant forests show high rates of species endemism, but experience degradation from climate change, wood-cutting, and livestock-grazing. Forest census data provide a vital resource for examining remote sensing methods to estimate diversity levels. We used spatially referenced trees ≥5 cm in diameter and simulated 0.10 ha plots measured from a 9 ha SDTF in southwestern Ecuador to compare machine learning (ML) models for six α-diversity indices. We developed 1 m tree canopy height and elevation models from stem mapped trees, at a scale conventionally derived from light detection and ranging (LiDAR). We then used an ensemble ML approach comparing single- and combined-sensor models from RapidEye, Sentinel-2 and interpolated canopy height and topography surfaces. Validation data showed that combined models often outperformed single-sensor approaches. Combined sensor and model ensembles for tree species richness, Shannon’s H, inverse Simpson’s, unbiased Simpson’s, and Fisher’s alpha indices typically showed lower root mean squared error (RMSE) and increased goodness of fit (R2). Piélou’s J, a measure of evenness, was poorly predicted. Mapped tree species richness (R2 = 0.54, F = 27.3, p = <0.001) and Shannon’s H′ (R2 = 0.54, F = 26.9, p = <0.001) showed the most favorable agreement with field validation observations (n = 25). Small-scale model experiments revealed essential relationships between dry forest tree diversity and data from multiple satellite sensors with repeated global coverage that can help guide larger-scale biodiversity mapping efforts.
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KÜLKAMP, JOSIMAR, JOÃO R. V. IGANCI, INÊS CORDEIRO, and JOSÉ FERNANDO A. BAUMGRATZ. "Ditaxis (Euphorbiaceae) from the Brazilian Caatinga, including a new species." Phytotaxa 455, no. 2 (2020): 152–60. http://dx.doi.org/10.11646/phytotaxa.455.2.6.
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Ditaxis is a Neotropical genus with approximately 50 species, most of them in seasonally dry tropical forests of Brazil, Central America and the Antilles. The Brazilian Caatinga, the largest area of SDTF in South America, harbors three endemic species of Ditaxis, including the new Ditaxis grazielae, hereby described and illustrated. The new species is known from a few localities in the state of Bahia. We provide an identification key for the species occurring in the Caatinga, as well as comments on habitat, distribution and phenology. We also present amended descriptions and typifications for Ditaxis desertorum and D. malpighiacea, and propose D. gardneri as synonym of D. desertorum.
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Ferreira, Maria Beatriz, Rinaldo Luiz Caraciolo Ferreira, Jose Antonio Aleixo da Silva, Robson Borges de Lima, Alex Nascimento de Sousa, and Marcos Vinícius da Silva. "Space–Time Dynamics of Mortality and Recruitment of Stems and Trees in a Seasonally Dry Tropical Forest: Effect of the 2012–2021 Droughts." Remote Sensing 17, no. 9 (2025): 1491. https://doi.org/10.3390/rs17091491.
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Seasonally dry tropical forests (SDTFs) represent about 41.5% of the planet’s tropical forests. The objective of this study was to characterize the annual mortality and recruitment patterns of stems and trees between the years 2012–2021 in a Caatinga remnant in the state of Pernambuco, Brazil, through geostatistical modeling, and to associate the drought events recorded in the region with vegetation dynamics. Mortality and recruitment of stems and trees were monitored in 80 permanent plots located in an SDTF remnant, counted year by year between 2012 and 2021. The standardized precipitation index (SPI) was calculated to quantify the deficit or excess of rainfall in the evaluated period. The data were then subjected to geostatistical analysis based on the calculation of classical semivariances. As a result, there was a loss of 68.33% of trees and 61.93% of stems in the forest community during 2012–2021, which were associated with the water deficit caused by drought events recorded based on precipitation data and SPI calculation for the region. The Gaussian semivariogram model better represented the spatial variability of mortality and recruitment of stems and trees. An accumulative effect of droughts on increasing mortality rates and reducing recruitment during the study period was observed. The relationship between tree and stem mortality and recruitment rates and drought events highlights the impact of water deficit on vegetation, emphasizing the importance of considering extreme climatic events in the proper management of natural resources.
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Lopes, José Frédson Bezerra, Fernando Bezerra Lopes, Isabel Cristina da Silva Araújo, et al. "How Forest Management with Clear-Cutting Affects the Regeneration, Diversity and Structure of a Seasonally Dry Tropical Forest in Brazil." Forests 14, no. 9 (2023): 1870. http://dx.doi.org/10.3390/f14091870.
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In Brazil, logging in the Seasonally Dry Tropical Forest (SDTF) under management plans that include clear-cutting has increased in recent decades, and the structure, composition, diversity and functioning of the forest likely must have been affected. The aim of this study was to understand the growth dynamics of shrub–tree biomass (STB), species richness and vegetation structure as a function of regeneration time after clear-cutting (treatments), taking the Legal Reserve (40 years of regeneration) as reference. The study was carried out in 2018 at the Ramalhete Settlement, General Sampaio, in the state of Ceará. All plants with a circumference at breast height (CBH) ≥ 6 cm were identified and the CBH was measured across 42 sample plots (20.0 m × 20.0 m), using seven plots per treatment (3, 5, 8, 11 and 15 years after clear-cutting, and the Legal Reserve, 40 years of regeneration). The following were determined: STB (total and by species), density and basal area (by ecological group and diameter class), basal area (species of higher added value), diversity (Hill numbers), and the importance value index (IVI). It was found that during the early years (up to at least 11 years), many important forest characteristics related to the composition of the ecological groups and vegetation structure were strongly affected, and major impacts can be seen, the effects of which, however, decreased over time of regeneration, having almost no effect after 15 years. After 15 years following clear-cutting, the SDTF presented accumulated STB, species richness and structure similar to the area undergoing regeneration for 40 years. However, the small number of indicator species of more-preserved areas (even at T15 and T40) points out that management needs to be improved. However, promoting species of greater added value and determining whether the forest recovers its structure and diversity after successive cutting cycles also still need to be addressed.
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Andrade, Eunice Maia, Maria Elinalda Ribeiro Costa, Júlio César Neves dos Santos, Helba Araujo De Queiroz Palácio, and Jacques Carvalho Ribeiro Filho. "Plant cover and hydrological response in a seasonally dry tropical forest (SDTF)." REVISTA AGRO@MBIENTE ON-LINE 11, no. 4 (2017): 258. http://dx.doi.org/10.18227/1982-8470ragro.v11i4.4556.
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Liu, Lu-Yao, Wen-Zhe Liu, and Lin Feng. "SDTF-Net: Static and dynamic time–frequency network for Speech Emotion Recognition." Speech Communication 148 (March 2023): 1–8. http://dx.doi.org/10.1016/j.specom.2023.01.008.
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Mogni, V. Y., L. J. Oakley, and D. E. Prado. "THE DISTRIBUTION OF WOODY LEGUMES IN NEOTROPICAL DRY FORESTS: THE PLEISTOCENE ARC THEORY 20 YEARS ON." Edinburgh Journal of Botany 72, no. 1 (2014): 35–60. http://dx.doi.org/10.1017/s0960428614000298.
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The Pleistocene Arc Theory (PAT) suggests that present-day disjunct fragments of dry forests in central tropical South America give evidence of a previously more continuous distribution during the Pleistocene that has been disrupted by dry-cold vs. humid-warm climatic cycles. This Arc extends from NE Brazil to NE Argentina and eastern Paraguay, through the Chiquitanía to NW Argentina and SW Bolivia and into the dry inter-Andean valleys in Peru and Ecuador, with intrusions into the Great Chaco. Seasonally Dry Tropical Forests (SDTFs) are floristically and physiognomically dominated by woody legumes, mostly deciduous in the dry season. In the last two decades field collection and research on legume taxa has greatly increased, with a significant number of taxonomic revisions and molecular phylogenetic studies, together with some paleoclimatic modelling studies. The evidence accumulated in the last 23 years has confirmed the integrity of the Chaco and Caatingas phytogeographical provinces, with an impressive and increasing level of botanical endemism discovered. The PAT pattern has also been supported, specifically through the mapping of five selected woody Leguminosae species (Anadenanthera colubrina, Enterolobium contortisiliquum, Pterogyne nitens, Amburana cearensis and Piptadenia viridiflora). The pre-existing nuclei of South American SDTF (Caatingas, Misiones and Piedmont) are now increased to four with the postulation of the Chiquitanía Nucleus in south-eastern Bolivia and bordering Paraguay. Some new endemisms are compiled from recent literature and mapped for the Misiones and Chiquitanía nuclei. The need for more botanical collections and further taxonomic, phylogenetic and demographic studies of South American legumes is emphasised.
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Channa, Imran Ali, and Abdullah Saand. "Mechanical Behavior of Concrete Reinforced with Waste Aluminium Strips." Civil Engineering Journal 7, no. 7 (2021): 1169–82. http://dx.doi.org/10.28991/cej-2021-03091718.
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The main objective of this research work is to investigate the influence of the addition of waste materials, like aluminium waste material, Soft Drink Tin Fibers (SDTF) or soft tins to improve mechanical properties of concrete and also study the strength behavior of concrete, such as flexural strength and indirect or split tensile strength. It has been acknowledged that the use of fibers in concrete has considerable effects to improve strength parameters and characteristics of concrete. In this research work, similar efforts are made to present the effects of soft tin fibers or aluminium waste material as a reinforcing material in concrete and to assess the mechanical behavior of concrete. Particularly, this research work aimed to investigate experimentally the effect of soft drink tins on tensile (cylinder splitting tensile strength) and flexural strength. Soft tin fibers of 25.4 5 0.5 mm in size were used and added from 1 to 5% by the weight of cement with the design mix of 1:1.624:2.760 at 0.50 w/c ratio. Therefore, 6 batches (every batch contained 3 prisms and 3 cylinders) were prepared and cast for evaluation of tensile and flexural strength. One batch was cast without inclusion of fibers (controlled batch) and remaining 5 batches were cast with the addition of fibers using 1, 2, 3, 4, and 5% respectively. It was revealed from obtained results that split tensile strength and flexural strength of specimen increases as compared to controlled batch up to 4% addition of fibers. Moreover, beyond 4% soft drink tin fiber level, strength begins to fall down. Thus, it can be suggested that mechanical properties of concrete can be enhanced by 4% of soft drink tin fibers. Moreover, in this study, soft drink tin fibers (SDTF) or aluminium waste are used as the application of utilization of waste materials as a partial construction material and also on another side it controls the solid waste and environmental pollution. Doi: 10.28991/cej-2021-03091718 Full Text: PDF
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Kaminski, Maciej, Jaroslaw Zygierewicz, Rafal Kus, and Nathan Crone. "Analysis of multichannel biomedical data." Acta Neurobiologiae Experimentalis 65, no. 4 (2005): 443–52. http://dx.doi.org/10.55782/ane-2005-1573.
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Nowadays, there is a common practice in biomedical research to perform multiple time series recordings. In the first part of this paper, basic information about analysis of such multichannel biomedical data is given. A short overview of important differences between single-channel, two-channel and multichannel data sets is presented and various coherence functions are reported. Causal relations between channels are investigated by means of the Directed Transfer Function (DTF) and its dynamic version, the Short-Time Directed Transfer Function (SDTF). The introduced formalism was used to analyze 12-channel human electrocorticogram (ECoG) records. Preliminary results of a study of causal dependence in beta and gamma frequency bands in two patients performing a motor task are reported. Specific characteristics in activity propagation consistent for both subjects for different rhythms were found.
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Jeux, Victorien, Clément Dalinot, Magali Allain, Lionel Sanguinet, and Philippe Leriche. "Synthesis of Spiro[cyclopenta[1,2-b:5,4-b′]DiThiophene-4,9′-Fluorenes] SDTF dissymmetrically functionalized." Tetrahedron Letters 56, no. 11 (2015): 1383–87. http://dx.doi.org/10.1016/j.tetlet.2015.01.173.
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Ginter, J., M. Kamiński, P. J. Durka, G. Pfurtscheller, C. Neuper, and K. J. Blinowska. "Propagation of EEG Activity in the Beta and Gamma Band during Movement Imagery in Humans." Methods of Information in Medicine 44, no. 01 (2005): 106–13. http://dx.doi.org/10.1055/s-0038-1633932.
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Summary Objectives: The objective of the paper was the determination of electrical brain activity propagation in sensorimotor areas during hand movement imagery. Methods: Right-hand and left-hand movement imagination was studied in three subjects. The 10-channel Multivariate Autoregressive Model (MVAR) was fitted to EEG signals recorded from subsets of electrodes overlying central and related brain areas. By means of the Short-time Directed Transfer Function (SDTF) the propagation of brain activity as a function of frequency and time was found. Results: During imagery the relation between propagations in gamma and beta bands changed significantly for electrodes overlying sensorimotor areas, namely the increase in gamma was accompanied by the decrease in the beta band. Conclusions: The hypothesis was put forward that these kinds of changes in flow of electrical brain activity are connected with the specific information processing.
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Kus, Rafal, Jozef Ginter, and And Blinowska. "Propagation of EEG activity during finger movement and its imagination." Acta Neurobiologiae Experimentalis 66, no. 3 (2006): 195–206. http://dx.doi.org/10.55782/ane-2006-1607.
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We investigated the pattern of EEG activity propagation in the beta and gamma band during a finger movement experiment and imagination of that task. The data were analyzed by means of a short-time directed transfer function (SDTF) based on a multivariate autoregressive model. The signals from the right (or left) hemisphere were processed simultaneously (not pairwise), which is crucial for obtaining a correct picture of EEG activity transmissions. The pattern of propagation in the beta band involved for both tasks a decrease of the propagation from the motor areas during the execution of the movement ? less pronounced in the case of imagination. The performance of the motion was mainly connected with a short outburst of gamma activity from the hand sensorimotor areas. In case of imagination the gamma outflow lasted longer and concerned larger brain areas.
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Du, Bowen, Qian Tao, Feng Zhu, and Tianshu Song. "Finding Optimal Team for Multiskill Task Based on Vehicle Sensors Data." Journal of Sensors 2017 (2017): 1–10. http://dx.doi.org/10.1155/2017/8568613.
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These days, with the increasingly widespread employment of sensors, particularly those attached to vehicles, the collection of spatial data is becoming easier and more accurate. As a result, many relevant areas, such as spatial crowdsourcing, are gaining ever more attention. A typical spatial crowdsourcing scenario involves an employer publishing a task and some workers helping to accomplish it. However, most of previous studies have only considered the spatial information of workers and tasks, while ignoring individual variations among workers. In this paper, we consider the Software Development Team Formation (SDTF) problem, which aims to assemble a team of workers whose abilities satisfy the requirements of the task. After showing that the problem is NP-hard, we propose three greedy algorithms and a multiple-phase algorithm to approximately solve the problem. Extensive experiments are conducted on synthetic and real datasets, and the results verify the effectiveness and efficiency of our algorithms.
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Finch, W. Holmes, and Brian F. French. "Effect Sizes for Estimating Differential Item Functioning Influence at the Test Level." Psych 5, no. 1 (2023): 133–47. http://dx.doi.org/10.3390/psych5010013.
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Differential item functioning (DIF) is a critical step in providing evidence to support a scoring inference in building a validity argument for a psychological or educational assessment. Effect sizes can assist in understanding the accumulation of DIF at the test score level. The current simulation study investigated the performance of several proposed effect size measures under a variety of conditions. Conditions under study included varied sample sizes, DIF effect sizes, the proportion of items with DIF, and the type of DIF (additive vs. non-additive). DIF effect sizes under study included sDTF%, uDTF%, τ^w2, d, R¯Δ2, IDIF2*, and S−DIF−V. The results of this study suggest that across study conditions, τ^w2, IDIF2*, and d were consistently the most accurate measures of the DIF effects. The effect sizes were also estimated in an empirical example. Recommendations and implications for practice are discussed.
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Marcelo-Peña, José Luis, Paúl Gonzáles, Tiina Särkinen, and Goodwin Zoë A. "Lista de plantas leñosas de los bosques estacionalmente secos del valle del Marañón, Perú." Revista Forestal del Perú 39, no. 2 (2025): 256–311. https://doi.org/10.21704/rfp.v39i2.1860.
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Seasonally dry tropical forests (SDTF) remain woefully understudied despite mounting evidence that they are highly threatened hotspots of biodiversity with large numbers of endemic species. The dry forests of the Marañón river valley in northern Peru is one such hotspot. However, threats to the ecosystem primarily due to agriculture and livestock farming, they are accelerating their de[1]struction, placing the unique species present at high risk. Here we present a preliminary annotated checklist of the woody plants of the dry forest of the Marañón valley, this list includes 413 species and infraspecific taxa, in 223 genera and 59 families. We estimate that 33 % of these taxa are en[1]demic. This list is expected to be incomplete given that large areas of the valley remain unexplored botanically. It is anticipated that this checklist will become a valuable resource for management and conservation of this unique ecosystem, and will act as a stimulus for further botanical exploration.
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Medeiros, Rodolpho, João Andrade, Desirée Ramos, et al. "Remote Sensing Phenology of the Brazilian Caatinga and Its Environmental Drivers." Remote Sensing 14, no. 11 (2022): 2637. http://dx.doi.org/10.3390/rs14112637.
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The Caatinga is the largest nucleus of Seasonally Dry Tropical Forests (SDTF) in the Neotropics. The leafing patterns of SDTF vegetation are adapted to the current environmental and climate variability, but the impacts of climate change tend to alter plants’ phenology. Thus, it is necessary to characterise phenological parameters and evaluate the relationship between vegetation and environmental drivers. From this information, it is possible to identify the dominant forces in the environment that trigger the phenological dynamics of the Caatinga. In this way, remote sensing represents an essential tool to investigate the phenology of vegetation, particularly as it has a long series of vegetation monitoring and allows relationships with different environmental drivers. This study has two objectives: (i) estimate phenological parameters using an Enhanced Vegetation Index (EVI) time-series over 20 years, and (ii) characterise the relationship between phenologic dynamics and environmental drivers. TIMESAT software was used to determine four phenological parameters: Start Of Season (SOS), End Of Season (EOS), Length Of Season (LOS), and Amplitude (AMPL). Boxplots, Pearson’s, and partial correlation coefficients defined relationships between phenologic dynamics and environmental drivers. The non-parametric test of Fligner–Killeen was used to test the interannual variability in SOS and EOS. Our results show that the seasonality of vegetation growth in the Caatinga was different in the three experimental sites. The SOS was the parameter that presented the greatest variability in the days of the year (DOY), reaching a variation of 117 days. The sites with the highest SOS variability are the same ones that showed the lowest EOS variation. In addition, the values of LOS and AMPL are directly linked to the annual distribution of rainfall, and the longer the rainy season, the greater their values are. The variability of the natural cycles of the environmental drivers that regulate the ecosystem’s phenology and the influence on the Caatinga’s natural dynamics indicated a greater sensitivity of the phenologic dynamics to water availability, with precipitation being the limiting factor of the phenologic dynamics. Highlights: The EVI time series was efficient in estimating phenological parameters. The high variability of the start of season (SOS) occurred in sites with low variability of end of the season (EOS) and vice versa. The precipitation and water deficit presented a higher correlation coefficient with phenological dynamics. Length of Season (LOS) and amplitude (AMPL) are directly linked to the annual distribution of rainfall.
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FAUSTINO-MAGALHAES, MAYARA D., LUIS N. PIACENTINI, and ADALBERTO J. SANTOS. "The desert wolf-spider genus Xenoctenus: two endemic species from the Brazilian Caatinga, and a redescription of the type-species, X. unguiculatus (Araneae: Xenoctenidae)." Zootaxa 5399, no. 5 (2024): 517–39. http://dx.doi.org/10.11646/zootaxa.5399.5.3.
Full textAbstract:
The Caatinga is a nucleus of seasonally dry tropical forest (SDTF) known as a hotspot of diversification and endemism. Despite its importance, this biome is still insufficiently sampled, resulting in extensive knowledge gaps regarding its species richness and composition. In this study we report two species of Xenoctenidae that are endemic to, and widely distributed in the Caatinga. We redescribe and illustrate Odo vittatus (Mello-Leitão, 1936), the only xenoctenid species previously known from the Caatinga. We transfer this species to Xenoctenus Mello-Leitão,1938, a genus currently known from six species restricted to Argentina, Bolivia, and Colombia. We also newly describe the male of Xenoctenus vittatus comb. nov. and provide new records of this species, which was hitherto known only from the type-locality, throughout the Caatinga and nearby semiarid vegetation formations. We also describe and illustrate a new species, Xenoctenus kaatinga sp. nov., based on males and female specimens collected throughout the Caatinga. Additionally, we propose diagnostic characters for Xenoctenus and redescribe the type-species, X. unguiculatus.
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de, Carvalho-Sobrinho Jefferson, Queiroz Luciano de, and Bil Alverson. "Reinterpretation of the nomenclatural type of Pseudobombax heteromorphum (Malvaceae, Bombacoideae) reveals an overlooked new species from Bolivia." PhytoKeys 21 (May 9, 2013): 53–61. https://doi.org/10.3897/phytokeys.21.5213.
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In the course of a taxonomic revision of <i>Pseudobombax </i>Dugand, one of us (JGCS) frequently has observed herbarium specimens of Bombacoideae that comprise a mixture of different Angiosperm families. In particular, <i>P. heteromorphum </i>(Kuntze) A.Robyns, a frequent name in checklists of the Bolivian flora, is based on type material of <i>Bombax heteromorphum </i>Kuntze that is clearly a mixture of <i>Pseudobombax</i> flowers and <i>Tabebuia </i>Gomes ex DC. (Bignoniaceae) leaves. We herein designate as the lectotype of <i>B. heteromorphum</i> the flowers of an herbarium sheet deposited in NY and as epitype a complete specimen (leaves, flowers, and fruit) in HUEFS. We consider <i>Bombax heteromorphum</i> to be a synonym of <i>P. longiflorum</i> (Mart.) A. Robyns, a species widespread in Neotropical seasonally dry forest of Bolivia, Brazil, Paraguay, and Peru. Furthermore, we describe a new species, <i>P. pulchellum </i>Carv.-Sobr., apparently endemic to seasonally dry tropical forest (SDTF) in Bolivia (Chiquitano dry forest), based on specimens commonly but incorrectly identified as <i>P. heteromorphum. </i>We also comment on the morphology, distribution, and conservation status of this new species.
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Teske, Milton E., Harold W. Thistle, and Bradley K. Fritz. "Modeling Aerially Applied Sprays: An Update to AGDISP Model Development." Transactions of the ASABE 62, no. 2 (2019): 343–54. http://dx.doi.org/10.13031/trans.13129.
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Abstract. AGDISP (AGricultural DISPersal) models the release of aerially applied sprays with a Lagrangian-based droplet tracking algorithm initialized by user inputs (aircraft description, spray boom nozzle locations, drop size distribution, spray material properties, release height, and meteorology). The model offers an extensive set of output plots and toolbox options (deposition, spray block, stream, and multiple application assessments) to predict the downwind behavior of released sprays and assess their potential environmental impact. The model is used in risk analysis, operational planning, post-operation analysis, and training, particularly by the USDA Forest Service (FS) and its cooperators, including the U.S. Environmental Protection Agency (USEPA), the U.S. Fish and Wildlife Service, the U.S. Department of Defense, and various other state and private entities. This article updates the further development of the model since 2003, including the implementation of a quadratic droplet evaporation model and its behavior as Reynolds number approaches zero, a more accurate time step algorithm tied to droplet settling velocity, an optical canopy model, a Gaussian model for far-field extension (downwind to 20 km), an Eulerian model for tracking volatile active spray material, and the Tier 1 ground and orchard assessments previously developed by the Spray Drift Task Force (SDTF). Keywords: Aerial application, AGDISP, Model, Spray drift.
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de Paula Sousa Júnior, Vicente, Javier Sparacino, Giovana Mira de Espindola, and Raimundo Jucier Sousa de Assis. "Land-Use and Land-Cover Dynamics in the Brazilian Caatinga Dry Tropical Forest." Conservation 2, no. 4 (2022): 739–52. http://dx.doi.org/10.3390/conservation2040048.
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The use of remote sensing to determine land-use and land-cover (LULC) dynamics is often applied to assess the levels of natural forest conservation and monitor deforestation worldwide. This study examines the loss of native vegetation in the Campo Maior Complex (CMC), in the Brazilian Caatinga dry tropical forest, from 2016 to 2020, considering the temporal distribution of rainfall and discussing the trends and impacts of forest-degradation vectors. The Google Earth Engine (GEE) platform is used to obtain the rainfall data from the CHIRPS collection and to create the LULC maps. The random forest classifier is used and applied to the Landsat 8 collection. The QGIS open software and its SPC plugin are used to visualize the LULC dynamics. The results show that the months from June to October have the lowest average rainfall, and that 2019 is the year with the highest number of consecutive rainy days below 5 mm. The LULC maps show that deforestation was higher in 2018, representing 20.19%. In 2020, the proportion of deforestation was the lowest (11.95%), while regeneration was the highest (20.33%). Thus, the characterization of the rainfall regime is essential for more accurate results in LULC maps across the seasonally dry tropical forests (SDTF).
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Apgaua, Deborah Mattos Guimarães, Rubens Manoel dos Santos, Diego Gualberto Sales Pereira, et al. "Beta-diversity in seasonally dry tropical forests (SDTF) in the Caatinga Biogeographic Domain, Brazil, and its implications for conservation." Biodiversity and Conservation 23, no. 1 (2013): 217–32. http://dx.doi.org/10.1007/s10531-013-0599-9.
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Hidosa, D., and KG Meskel. "Impact of cattle night corralling on soil properties and vegetation in the semiarid degraded rangeland of Ethiopia." Bangladesh Journal of Animal Science 51, no. 4 (2022): 152–62. http://dx.doi.org/10.3329/bjas.v51i4.63566.
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In Ethiopia, rangeland degradation is a severe environmental problem. To improve rangeland vegetation cover and support the rangeland-based livelihoods, it is imperative to repair degraded rangeland using different rehabilitative measures. This study was carried out to evaluate the effects of night cattle corralling impact on soil chemical parameters, herbaceous species compositions and biomass yield of degraded rangeland. To conduct the experiment, severely degraded (SD) and moderately degraded (MD) rangelands with an area size of 30m x10m (300m2) each was identified. Then, each of the selected rangeland types was separated into two paddocks with an area size of 10m x 15m (150 m2). The treatment paddocks of the severely and moderately degraded rangeland were treated by cattle impact tools corralling cattle every night in the paddock for one month (SDT1 and MDT1). While the second paddock in both rangeland types was used as a control without cattle impact tools (SDT2 and MDT2). A randomized complete block design was used and each treatment was replicated three times. The results showed that soil chemical parameters and herbaceous species compositions in both degraded rangeland paddocks treated with cattle impact tools (SDT1 and MDT1) changed significantly (p<0.05) than paddocks without cattle impact tools (SDT2 and MDT2). Likewise, there was an increased difference (p<0.05) in biomass yields of 2.98 ton/ha and 5.35ton/ha from severely and moderately degraded rangeland, respectively for paddocks treated with cattle impact tools (SDT1 and MDT2), compared to paddocks of biomass yield of 0.98 ton/ha and 2.78 ton/ha without cattle impact tools treatments for SDT2 and MDT2 respectively. Thus the result from this study emphasized the advantage of night cattle corralling impact tools for improved soil parameters and herbaceous species compositions of degraded rangeland. Hence, we concluded that employing cattle impact tools to restore degraded rangeland significantly improved soil physico-chemical properties, with ultimate effect on vegetation cover, vegetation compositions and herbaceous biomass yield, attributed from soil seed bank growth. Bangladesh Journal of Animal Science 51 (4): 152-162
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Wöhrmann, Tina, Ingo Michalak, Georg Zizka, and Kurt Weising. "Strong genetic differentiation among populations of Fosterella rusbyi (Bromeliaceae) in Bolivia." Botanical Journal of the Linnean Society 192, no. 4 (2019): 744–59. http://dx.doi.org/10.1093/botlinnean/boz096.
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Abstract The terrestrial bromeliad Fosterella rusbyi is endemic to the Bolivian Andes, where it mainly grows on steep, exposed slopes along roadsides and riverbeds in the seasonally dry tropical forest (SDTF) and the mesic montane forest (Yungas) biomes. We hypothesize that allopatric speciation may have been a main driver of diversification in Fosterella since the Miocene and that the scattered distribution of suitable habitats fostered the evolution of the high degree of endemism observed today. To provide further information relating to this hypothesis, we analysed the partition of genetic diversity and the extent of gene flow among natural populations of F. rusbyi using plastid and nuclear microsatellite markers. Nineteen plastid haplotypes were found, but the mean haplotype diversity per population was low. Nuclear microsatellite markers revealed 177 different multilocus genotypes (MLGs), of which 31 occurred in more than one plant. Recurrent MLGs were found in 76 plants that were therefore identified as clones. A considerable deficit of heterozygotes was detected at all nuclear loci. Geographical and genetic distances between populations were only weakly correlated with each other. Genetic divergence between populations was extremely high for both marker classes, suggesting that seed and pollen flow are low, even over short distances. The observed patterns are consistent with our hypothesis that newly available sites are sporadically colonized by one or a few founders, followed by in situ population expansion via vegetative propagation, self-pollination and/or biparental inbreeding, genetic differentiation among persistent populations and, ultimately, allopatric speciation.
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Carrión, Juan F., Stapf María S. de, and Maryolis Lino. "First record of Pleradenophora Esser (Euphorbiaceae) for the flora of Panama." Check List 20, no. (4) (2024): 874–79. https://doi.org/10.15560/20.4.874.
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<em>Pleradenophora membranifolia</em> (Müll. Arg.) Esser & A.L. Melo (Euphorbiaceae) was previously only known from central South America (Bolivia, Brazil, and Peru). Our new botanical collections from the seasonal dry forests in Garachiné, Darién Province, Panama increase the distribution of this species to Central America and include the first record of this genus for the country. We also provide photographs of field and herbarium specimens, an occurrence map, a description, and comments on the morphology and taxonomy of <em>P. membranifolia.</em>