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1
Galindo-Leal, Carlos. "Live-trapping vs. snap-trapping of deer mice: a comparison of methods." Acta Theriologica 35 (June 9, 1990): 357–63. http://dx.doi.org/10.4098/at.arch.90-40.
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Luescher, Michael, and Jeffrey Bode. "Evidence for a Radical Mechanism in Cu(II)-Promoted SnAP Reactions." Synlett 30, no. 04 (February 5, 2019): 464–70. http://dx.doi.org/10.1055/s-0037-1611670.
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Saturated nitrogen heterocycles can be found with increasing abundance in bioactive molecules despite a limited number of methods to access these scaffolds. However, the coupling of recently introduced SnAP [tin (Sn) amine protocol] reagents with a wide range of aldehydes and ketones has proven to be a reliable, practical, and versatile one-step approach to saturated N-heterocycles. While effective, the lack of mechanistic understanding limits efforts to develop new catalytic and enantioselective variants. To distinguish between a polar or radical mechanism, we assessed Lewis and Brønsted acids, radical trapping experiments, and radical clock SnAP reagents reinforcing the current understanding of the SnAP protocol as a radical cyclization.
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Whitman, Jackson S. "Diet and Prey Consumption Rates of Nesting Boreal Owls, Aegolius funereus, in Alaska." Canadian Field-Naturalist 123, no. 2 (April 1, 2009): 112. http://dx.doi.org/10.22621/cfn.v123i2.688.
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Dietary composition and prey consumption rates of nesting Boreal Owls, Aegolius funereus, were investigated during 2004–2006 using two methods. Dietary composition was determined during nest visits through examination of 1882 fresh remains containing at least 11 mammalian and 15 avian species. Consumption rates were calculated based on laboratory examination of seven prey detritus bricks following fledging, yielding 1051 items of five different taxa. During 2003–2006, small mammal snap-trapping was conducted in the vicinity of occupied nest boxes, and relative abundance of potential prey items was estimated. A total of 4020 trap-nights yielded 695 small mammal captures of eight species. Consumption rates of nestling owls ranged from 22.0 to 29.7 g of food per day, averaging 24.2 g (SD = 1.8). Comparisons between availability of small mammals (as indicated by snap-trapping) and consumption (as indicated by nest visits and analysis of prey detritus bricks) showed that Boreal Owls are generally preying on mammals proportionate to their occurrence.
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Srilakshmi, Gollapudi Venkata, and Arabinda Chaudhuri. "“Snap-Shooting” the Interface of AOT Reverse Micelles: Use of Chemical Trapping." Chemistry - A European Journal 6, no. 15 (August 4, 2000): 2847–53. http://dx.doi.org/10.1002/1521-3765(20000804)6:15<2847::aid-chem2847>3.0.co;2-q.
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Village, A., and D. Myhill. "Estimating small mammal abundance for predator studies: snap-trapping versus sign indices." Journal of Zoology 222, no. 4 (December 1990): 681–89. http://dx.doi.org/10.1111/j.1469-7998.1990.tb06023.x.
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Holt, Denver W., Michael T. Maples, and Chris Savok. "Black Color Morph of the Brown Lemming, Lemmus trimucronatus = L. sibiricus." Canadian Field-Naturalist 117, no. 3 (July 1, 2003): 466. http://dx.doi.org/10.22621/cfn.v117i3.808.
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A black pelage Brown Lemming is reported from Barrow, Alaska. The occurrence of this black color morph appears to be rare. During twelve years of Snowy Owl research and lemming trapping, only one has been seen. Of 554 snap-trapped Brown Lemmings and 1649 Brown Lemmings found cached at owl nests, no black individuals were found. The pelage of the black morph is described using a Munsell Soil Color Chart.
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Zhang, Zhiwei, Simon Pusateri, Binglin Xie, and Nan Hu. "Tunable energy trapping through contact-induced snap-through buckling in strips with programmable imperfections." Extreme Mechanics Letters 37 (May 2020): 100732. http://dx.doi.org/10.1016/j.eml.2020.100732.
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Barney, Sarah K., Devin R. Leopold, Kainana Francisco, David J. Flaspohler, Tadashi Fukami, Christian P. Giardina, Daniel S. Gruner, Jessie L. Knowlton, William C. Pitt, and Erin E. Wilson Rankin. "Successful management of invasive rats across a fragmented landscape." Environmental Conservation 48, no. 3 (June 23, 2021): 200–207. http://dx.doi.org/10.1017/s0376892921000205.
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SummaryIntroduced mammalian predators are responsible for the decline and extinction of many native species, with rats (genus Rattus) being among the most widespread and damaging invaders worldwide. In a naturally fragmented landscape, we demonstrate the multi-year effectiveness of snap traps in the removal of Rattus rattus and Rattus exulans from lava-surrounded forest fragments ranging in size from <0.1 to >10 ha. Relative to other studies, we observed low levels of fragment recolonization. Larger rats were the first to be trapped, with the average size of trapped rats decreasing over time. Rat removal led to distinct shifts in the foraging height and location of mongooses and mice, emphasizing the need to focus control efforts on multiple invasive species at once. Furthermore, because of a specially designed trap casing, we observed low non-target capture rates, suggesting that on Hawai‘i and similar islands lacking native rodents the risk of killing non-target species in snap traps may be lower than the application of rodenticides, which have the potential to contaminate food webs. These efforts demonstrate that targeted snap-trapping is an effective removal method for invasive rats in fragmented habitats and that, where used, monitoring of recolonization should be included as part of a comprehensive biodiversity management strategy.
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Harper, Grant, and Dick Veitch. "Population ecology of Norway rats (Rattus norvegicus) and interference competition with Pacific rats (R. exulans) on Raoul Island, New Zealand." Wildlife Research 33, no. 7 (2006): 539. http://dx.doi.org/10.1071/wr05096.
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Norway rats (Rattus norvegicus) are sympatric with, and more often trapped, than the smaller Pacific rat (R. exulans) on Raoul Island, New Zealand. Rats were removed from a four-hectare grid by trapping and poisoning in the winters of 1994, 1995 and 1996. Pacific rats were trapped in increasing numbers only after Norway rats were removed. Norway rats also ate significantly more bait than Pacific rats. Competitive interference of Pacific rats by Norway rats was apparent, which casts doubt on the ability to accurately monitor individual species abundance within assemblages of rat species and to effectively manage them in control grids. Snap-trapping lines provided baseline data on the abundance of the two species before, during and after the removal grids were operated. Maximum abundances of rats were recorded in late summer and autumn following spring and summer breeding.
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Xia, Xuhua, and John S. Millar. "Sex-related dispersion of breeding deer mice in the Kananaskis Valley, Alberta." Canadian Journal of Zoology 64, no. 4 (April 1, 1986): 933–36. http://dx.doi.org/10.1139/z86-141.
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Snap trapping of small mammals in the Kananaskis Valley, Alberta, during the breeding seasons of 1982 and 1983 provided data used to analyse sex-related dispersion patterns of adult Peromyscus maniculatus. A dispersion pattern of regular alternation of males and females, within-sex avoidance, and strong between-sex association was found. Within-sex exclusion was better exhibited by females than by males. These data are consistent with what would be expected for a promiscuous mating system. Intraspecific resource partitioning between different sexes may occur through adjustments in spatial relationships.
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Marinelli, Lui, and John S. Millar. "The ecology of beach-dwelling Peromyscus maniculatus on the Pacific Coast." Canadian Journal of Zoology 67, no. 2 (February 1, 1989): 412–17. http://dx.doi.org/10.1139/z89-061.
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Live- and snap-trapped Peromyscus maniculatus from Barkley Sound, B.C., were compared between beach and inland habitats as well as between island and mainland populations. Densities, as indicated by trapping success, were not consistently different between beach and inland habitats, although the islands appeared to be more densely populated than the mainland. Mice in beach and inland habitats showed fidelity to those sites. Pregnancy rates were higher in beach habitats than in inland habitats. Beach mice were also larger, but less fat, than inland mice. We suggest that future comparisons between island and mainland populations take into consideration the variance in demographic and morphological parameters within, as well as among, islands.
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Zhao, Yinghao, Amal Jerald Joseph Maria Joseph, Zhiwei Zhang, Chunping Ma, Davut Gul, Andrew Schellenberg, and Nan Hu. "Deterministic snap-through buckling and energy trapping in axially-loaded notched strips for compliant building blocks." Smart Materials and Structures 29, no. 2 (January 17, 2020): 02LT03. http://dx.doi.org/10.1088/1361-665x/ab6486.
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Munawar, Nadeem, Iftikhar Hussain, and Tariq Mahmood. "EVALUATION OF DIFFERENT FOOD BAITS BY USING TRAPS FOR THE CONTROL OF LESSER BANDICOOT RAT (BANDICOTA BENGALENSIS) IN FIELD CROPS OF POTHWAR PLATEAU, PAKISTAN." World Journal of Biology and Biotechnology 4, no. 2 (August 15, 2019): 17. http://dx.doi.org/10.33865/wjb.004.02.0216.
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The lesser bandicoot rat (Bandicota bengalensis) is a widely distributed and serious agricultural pest in Pakistan. It has wide adaptation with rice-wheat-sugarcane cropping systems of Punjab, Sindh and Khyber Pakhtunkhwa provinces and wheat-groundnut cropping system of the Pothwar area, thus inflicting heavy losses to these crops. Comparative efficacies of four food baits (onion, guava, potato and peanut butter smeared bread/Chapatti) were tested in multiple feeding tests for snap/kill trapping of this rodent species in the Pothwar Plateau between October 2013 to July 2014 at the sowing, tillering, flowering and maturity stages of wheat, groundnut and millet crops. The results revealed that guava was the most preferred bait for the rat species as compared to the other three. Among relative efficacies of all four tested baits: guava scoring the highest trapping success (16.94 ± 1.42 percent), followed by peanut butter, potato and onion (10.52 ± 1.30, 7.82 ± 1.21 and 4.5 ± 1.10 percent) respectively. Crop stage/season-wise highest trapping success was achieved at maturity stages of the crop. Moreover, the maturity stage of wheat crop coincided with spring breeding season and maturity stages of millet and groundnut matched with monsoon/autumn breeding peak of the lesser bandicoot rat in the Pothwar area. Preferred order among four baits tested was guava > peanut butter > potato > onion.
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Bauer, Ulrike, Ulrike K. Müller, and Simon Poppinga. "Complexity and diversity of motion amplification and control strategies in motile carnivorous plant traps." Proceedings of the Royal Society B: Biological Sciences 288, no. 1951 (May 26, 2021): 20210771. http://dx.doi.org/10.1098/rspb.2021.0771.
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Similar to animals, plants have evolved mechanisms for elastic energy storage and release to power and control rapid motion, yet both groups have been largely studied in isolation. This is exacerbated by the lack of consistent terminology and conceptual frameworks describing elastically powered motion in both groups. Iconic examples of fast movements can be found in carnivorous plants, which have become important models to study biomechanics, developmental processes, evolution and ecology. Trapping structures and processes vary considerably between different carnivorous plant groups. Using snap traps, suction traps and springboard-pitfall traps as examples, we illustrate how traps mix and match various mechanisms to power, trigger and actuate motions that contribute to prey capture, retention and digestion. We highlight a fundamental trade-off between energetic investment and movement control and discuss it in a functional-ecological context.
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Westermeier, Anna S., Natalie Hiss, Thomas Speck, and Simon Poppinga. "Functional–morphological analyses of the delicate snap-traps of the aquatic carnivorous waterwheel plant (Aldrovanda vesiculosa) with 2D and 3D imaging techniques." Annals of Botany 126, no. 6 (August 11, 2020): 1099–107. http://dx.doi.org/10.1093/aob/mcaa135.
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Abstract Background and Aims The endangered aquatic carnivorous waterwheel plant (Aldrovanda vesiculosa) catches prey with 3–5-mm-long underwater snap-traps. Trapping lasts 10–20 ms, which is 10-fold faster than in its famous sister, the terrestrial Venus flytrap (Dionaea muscipula). After successful capture, the trap narrows further and forms a ‘stomach’ for the digestion of prey, the so-called ‘sickle-shaped cavity’. To date, knowledge is very scarce regarding the deformation process during narrowing and consequent functional morphology of the trap. Methods We performed comparative analyses of virtual 3D histology using computed tomography (CT) and conventional 2D histology. For 3D histology we established a contrasting agent-based preparation protocol tailored for delicate underwater plant tissues. Key Results Our analyses reveal new structural insights into the adaptive architecture of the complex A. vesiculosa snap-trap. In particular, we discuss in detail the arrangement of sensitive trigger hairs inside the trap and present actual 3D representations of traps with prey. In addition, we provide trap volume calculations at different narrowing stages. Furthermore, the motile zone close to the trap midrib, which is thought to promote not only the fast trap closure by hydraulics but also the subsequent trap narrowing and trap reopening, is described and discussed for the first time in its entirety. Conclusions Our research contributes to the understanding of a complex, fast and reversible underwater plant movement and supplements preparation protocols for CT analyses of other non-lignified and sensitive plant structures.
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R. Malcolm, Trent, Kirsty J. Swinnerton, Jim J. Groombridge, Bill D. Sparklin, Christopher N. Brosius, John P. Vetter, and Jeffrey T. Foster. "Ground-based rodent control in a remote Hawaiian rainforest on Maui." Pacific Conservation Biology 14, no. 3 (2008): 206. http://dx.doi.org/10.1071/pc080206.
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Effective control of introduced mammalian predators is essential to the recovery of native bird species in Hawai?i. Between August 1996 and December 2004, introduced rodents were controlled within three home ranges of the Po?ouli Melamprosops phaeosoma, a critically endangered Hawaiian honeycreeper. Rats were controlled using a combination of ground-based rodenticide (0.005% diphacinone) application and snap traps. Beginning in August 2001, we monitored the effectiveness of these rodent control efforts. Relative abundances of Black Rats Rattus rattus and Polynesian Rats R. exulans were measured in each of five snap-trapping grids seven times over a 35-month period. Rat populations decreased inside of the rodent control areas, but control effectiveness differed between rat species. During the first year of monitoring, target control levels for R. rattus were consistently achieved in only one of the rodent control areas. Control techniques were refined in areas failing to meet targets. Subsequently, we achieved target control levels for R. rattus more consistently in all three rodent control areas. However, relative abundances of R. exulans did not differ between rodent control and reference areas, indicating that our rodent control techniques were insufficient to reduce population levels of this species. These findings signify a need for further improvement of rodent control methods in Hawai?i, especially for Polynesian Rats, and demonstrate the critical importance of periodic monitoring of the response of rodent populations to management. In the future, managers may need to design rodent control operations targeting R. rattus and R. exulans independently to achieve best results.
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Bertin, Henri, Estefania Del Campo Estrada, and Olivier Atteia. "Foam placement for soil remediation." Environmental Chemistry 14, no. 5 (2017): 338. http://dx.doi.org/10.1071/en17003.
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Environmental contextSoil pollution is an important concern and remediation techniques, especially in situ techniques, should be studied. We investigate a new technique based on foam generation and placement inside the porous soil to improve the pollutant extraction. This technique could be useful when the soils are heterogeneous because it allows a complete soil sweeping. AbstractFoam can be generated in porous media, mainly by snap-off phenomena, by co-injecting gas and a surfactant solution. The liquid films that separate the gas bubbles, called lamellae, and gas trapping in small pores where capillary pressure is high generate a resistance to flow that drastically decreases fluid mobilities in porous media. Experiments performed with a 2D laboratory pilot consisting of two layers with different properties clearly highlight that foam is generated in the high-permeability layer and will divert flow towards the low-permeability region. This behaviour is of great interest for the remediation of heterogeneous polluted soils.
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Schulze, Waltraud X., Kristian W. Sanggaard, Ines Kreuzer, Anders D. Knudsen, Felix Bemm, Ida B. Thøgersen, Andrea Bräutigam, et al. "The Protein Composition of the Digestive Fluid from the Venus Flytrap Sheds Light on Prey Digestion Mechanisms." Molecular & Cellular Proteomics 11, no. 11 (August 12, 2012): 1306–19. http://dx.doi.org/10.1074/mcp.m112.021006.
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The Venus flytrap (Dionaea muscipula) is one of the most well-known carnivorous plants because of its unique ability to capture small animals, usually insects or spiders, through a unique snap-trapping mechanism. The animals are subsequently killed and digested so that the plants can assimilate nutrients, as they grow in mineral-deficient soils. We deep sequenced the cDNA from Dionaea traps to obtain transcript libraries, which were used in the mass spectrometry-based identification of the proteins secreted during digestion. The identified proteins consisted of peroxidases, nucleases, phosphatases, phospholipases, a glucanase, chitinases, and proteolytic enzymes, including four cysteine proteases, two aspartic proteases, and a serine carboxypeptidase. The majority of the most abundant proteins were categorized as pathogenesis-related proteins, suggesting that the plant's digestive system evolved from defense-related processes. This in-depth characterization of a highly specialized secreted fluid from a carnivorous plant provides new information about the plant's prey digestion mechanism and the evolutionary processes driving its defense pathways and nutrient acquisition.
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Bauer, Ulrike, Marion Paulin, Daniel Robert, and Gregory P. Sutton. "Mechanism for rapid passive-dynamic prey capture in a pitcher plant." Proceedings of the National Academy of Sciences 112, no. 43 (October 5, 2015): 13384–89. http://dx.doi.org/10.1073/pnas.1510060112.
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Plants use rapid movements to disperse seed, spores, or pollen and catch animal prey. Most rapid-release mechanisms only work once and, if repeatable, regaining the prerelease state is a slow and costly process. We present an encompassing mechanism for a rapid, repeatable, passive-dynamic motion used by a carnivorous pitcher plant to catch prey. Nepenthes gracilis uses the impact of rain drops to catapult insects from the underside of the canopy-like pitcher lid into the fluid-filled trap below. High-speed video and laser vibrometry revealed that the lid acts as a torsional spring system, driven by rain drops. During the initial downstroke, the tip of the lid reached peak velocities similar to fast animal motions and an order of magnitude faster than the snap traps of Venus flytraps and catapulting tentacles of the sundew Drosera glanduligera. In contrast to these active movements, the N. gracilis lid oscillation requires neither mechanical preloading nor metabolic energy, and its repeatability is only limited by the intensity and duration of rainfall. The underside of the lid is coated with friction-reducing wax crystals, making insects more vulnerable to perturbations. We show that the trapping success of N. gracilis relies on the combination of material stiffness adapted for momentum transfer and the antiadhesive properties of the wax crystal surface. The impact-driven oscillation of the N. gracilis lid represents a new kind of rapid plant movement with adaptive function. Our findings establish the existence of a continuum between active and passive trapping mechanisms in carnivorous plants.
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Innes, Duncan G. L., and James F. Bendell. "The effects on small-mammal populations of aerial applications of Bacillus thuringiensis, fenitrothion, and Matacil® used against jack pine budworm in Ontario." Canadian Journal of Zoology 67, no. 5 (May 1, 1989): 1318–23. http://dx.doi.org/10.1139/z89-186.
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In late June 1985, both operational and experimental aerial spraying was conducted against an outbreak of jack pine budworm (Choristoneura pinus) in northern Ontario. We report the effects of the insecticides Bacillus thuringiensis, fenitrothion, and Matacil® on populations of rodents and shrews in young (20 years) and medium-aged (40 years) jack pine (Pinus banksiana) plantations. Live, snap, and pitfall traps were used to monitor small-mammal populations from early June to late August on four sprayed plots and two control plots. We found no statistically significant differences in abundances that could be attributed to an insecticide. However, pitfall trapping suggested that the abundance of shrews was altered by the fenitrothion spray. Both the pattern and magnitude of shrew captures was different relative to a control and two other treatment plots. This difference may have resulted from the lack of available prey (arthropods) on the fenitrothion plot. With the exception of fenitrothion, our results agree with other studies which suggest that standard applications of insecticides to control forest insects have no detectable or only limited impact on small mammals.
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Ciechanowski, Mateusz, Jan Cichocki, Agnieszka Ważna, and Barbara Piłacińska. "Small-mammal assemblages inhabiting Sphagnum peat bogs in various regions of Poland." Biological Letters 49, no. 2 (December 1, 2012): 115–33. http://dx.doi.org/10.2478/v10120-012-0013-4.
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Abstract We studied species composition of assemblages of small mammals (rodents and shrews) inhabiting Polish 25 ombrotrophic mires and quaking bogs in several regions in order to reveal characteristic features of their quantitative structure and compare them between regions, internal zones of the bog habitats, and different levels of anthropogenic degradation. We reviewed also all published results of small-mammal trapping in such habitats. Mammals were captured in pitfalls, snap traps and live traps on 12 bogs of the Pomerania region, 4 bogs of the Orawa-Nowy Targ Basin (Kotlina Orawsko-Nowotarska), 3 bogs in the Świętokrzyskie Mts, and 6 bogs in Wielkopolska and the Lubusz Land. Additionally, we included materials collected from Barber traps (pitfalls) used during studies of epigeic invertebrates on 4 bogs. In total, 598 individuals of 12 species were collected. The number of pitfall captures per 100 trapnights was very low (7.0-7.8), suggesting low population density. Shrews predominated among mammals captured in pitfalls, and the assemblage structure appeared to be similar to impoverished forest fauna, slightly enriched with ubiquitous species from meadows and agroecosystems, with a very small percentage of typical wetland species (Neomys fodiens, Neomys anomalus, Microtus oeconomus). Rodents (mostly Myodes glareolus) predominated only in samples obtained by live and snap traps. Pygmy shrew Sorex minutus was the most numerous species at most sites, sometimes being the only small mammal in that habitat, especially in well-preserved, treeless parts of bogs, dominated by Sphagnum peatmoss. The dominance and high constancy of S. minutus appear to be a characteristic feature of small-mammal assemblages inhabiting ombrotrophic mires, at least in some regions of Central and Western Europe. Enrichment of the fauna with other species might be related to either improved trophic conditions (by contact with mineralized ground waters) or habitat degradation (by peat mining, drainage, and subsequent secondary succession).
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Sehgal, Pravin B., Somshuvra Mukhopadhyay, Fang Xu, Kirit Patel, and Mehul Shah. "Dysfunction of Golgi tethers, SNAREs, and SNAPs in monocrotaline-induced pulmonary hypertension." American Journal of Physiology-Lung Cellular and Molecular Physiology 292, no. 6 (June 2007): L1526—L1542. http://dx.doi.org/10.1152/ajplung.00463.2006.
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Monocrotaline (MCT)-induced pulmonary hypertension (PH) in the rat is a widely used experimental model. We have previously shown that MCT pyrrole (MCTP) produces loss of caveolin-1 (cav-1) and endothelial nitric oxide synthase from plasma membrane raft microdomains in pulmonary arterial endothelial cells (PAEC) with the trapping of these proteins in the Golgi organelle (the Golgi blockade hypothesis). In the present study, we investigated the mechanisms underlying this intracellular trafficking block in experiments in cell culture and in the MCT-treated rat. In cell culture, PAEC showed trapping of cav-1 in Golgi membranes as early as 6 h after exposure to MCTP. Phenotypic megalocytosis and a reduction in anterograde trafficking (assayed in terms of the secretion of horseradish peroxidase derived from exogenously transfected expression constructs) were evident within 12 h after MCTP. Cell fractionation and immunofluorescence techniques revealed the marked accumulation of diverse Golgi tethers, soluble N-ethylmaleimide-sensitive factor (NSF) attachment protein receptors (SNAREs), and soluble NSF attachment proteins (SNAPs), which mediate membrane fusion during vesicular trafficking (GM130, p115, giantin, golgin 84, clathrin heavy chain, syntaxin-4, -6, Vti1a, Vti1b, GS15, GS27, GS28, SNAP23, and α-SNAP) in the enlarged/circumnuclear Golgi in MCTP-treated PAEC and A549 lung epithelial cells. Moreover, NSF, an ATPase required for the “disassembly” of SNARE complexes subsequent to membrane fusion, was increasingly sequestered in non-Golgi membranes. Immunofluorescence studies of lung tissue from MCT-treated rats confirmed enlargement of perinuclear Golgi elements in lung arterial endothelial and parenchymal cells as early as 4 days after MCT. Thus MCT-induced PH represents a disease state characterized by dysfunction of Golgi tethers, SNAREs, and SNAPs and of intracellular vesicular trafficking.
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Balčiauskas, Linas, and Laima Balčiauskienė. "On the Doorstep, Rodents in Homesteads and Kitchen Gardens." Animals 10, no. 5 (May 15, 2020): 856. http://dx.doi.org/10.3390/ani10050856.
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Scarcely investigated in terms of small mammals, kitchen gardens and homesteads form a subset of environments. Using results of snap trapping, we present the first data on small mammal species diversity, gender and age structure, relative abundance, body fitness, and reproduction parameters in these commensal habitats (kitchen gardens, homestead gardens, houses, and outbuildings). We expected that (i) house mice should be the dominant species in buildings, while striped field mice should be dominant in gardens, (ii) body condition should be the highest in buildings, (iii) body condition should increase in the autumn, irrespective of the habitat, and (iv) breeding failures in the form of disrupted pregnancies should be observed. Not all of the predictions were confirmed. From the seven recorded species, gardens and outbuildings were dominated by yellow-necked mice, while bank voles dominated in buildings where food was available. The number of recorded species and diversity index increased during the autumn months. The body condition was highest in rodents that were trapped in gardens. It decreased towards winter, with the exception of the striped field mouse. Breeding disturbances were recorded in all of the most numerous species, comprising 16.7–100% of all observed pregnancies.
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Solonen, T., and P. Ahola. "Intrinsic and extrinsic factors in the dynamics of local small-mammal populations." Canadian Journal of Zoology 88, no. 2 (February 2010): 178–85. http://dx.doi.org/10.1139/z09-138.
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We studied dynamics of local small-mammal assemblages consisting of shrews, voles, and mice by small-scale snap trapping in each spring and autumn from 1981 to 2006 in southern Finland. Our aim was to search for relative roles of possible regulatory associations within and between species, as well as to find reflections of the effects of large-scale climatic phenomena on local populations. Preceding intraspecific densities had a dominating role in seasonal changes in small-mammal numbers. Their relationships with weather-related factors indicated by the indices of the North Atlantic Oscillation (NAO) were most pronounced during winter. Relationships with the NAO indices, increasing values of which indicate milder weather in the north, were negative in voles but positive in shrews and mice. Spring densities were governed by the largely compensatory effects of the growth rate of the preceding summer and subsequent population decline during winter in the field vole ( Microtus agrestis (L., 1761)) and mice, while the effects of winter decline dominated in shrews. The bank vole ( Myodes glareolus (Schreber, 1780) = Clethrionomys glareolus (Schreber, 1780)) showed decreasing winter decline, which had a considerable positive effect on population densities.
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Herawati, Nur ‘Aini, and Sudarmaji. "Diversity of Rodent Species and Its Potency as the Vector for Transmitting Rodent Borne Parasitic Disease in Households." BIO Web of Conferences 33 (2021): 07004. http://dx.doi.org/10.1051/bioconf/20213307004.
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Rodent species have been known as the major pest in the agricultural sector leading to economic losses. They are also identified as the vector for several rodent -borne zoonotic diseases. However, a specific study on observing their diversity in households closed to lowland irrigated agroecosystems that correspond to disease distribution’s role is limited. To address this issue, a field study was performed during the 2019 -2020 cropping season in two sites (Yogyakarta and West Java) which were categorized as the rice production centers. Trapping was conducted consecutively for 13-30 days using 65-75 snap traps. Roasted coconut and salty fish were used to attract rodents. In West Java, 3 rodent species ( Rattus argentiventer, Rattus tanezumi, Bandicota indica) and insectivore small mammal (Suncus murinus) were discovered from 1,950 trap nights. Meanwhile, the setting of 900 trap nights in Yogyakarta indicated less diverse rodents with only one species (Rattus tanezumi) and the same insectivore discovered. All captured animals were dissected and observed for the endoparasites. We obtained two potent species of parasites ( Taenia taeniaeformis and Capillaria hepatica), which can be transmitted by rodents to the local people if they do not apply a proper health practice.
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Čermák, P., and J. Ježek. "Effect of tree seed crop on small mammal populations and communities in oak and beech forests in the Drahany Upland (Czech Republic) ." Journal of Forest Science 51, No. 1 (January 10, 2012): 6–14. http://dx.doi.org/10.17221/4539-jfs.
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In 2002 (year with poor seed crop) and 2003 (year with good seed crop), the trapping of small mammals was carried out into standard snap-traps on transects situated in the area of the Křtiny Training Forest Enterprise, U buku locality (the Drahany Upland). The trapping was carried out in both years once a month in the period of September–November, in two types of forest of the community Querci-fageta: in a stand dominated by oak and in a stand dominated by beech. In total, 146 individuals were recorded, out of them 142 rodents – Apodemus flavicollis <br />(81 individuals), Apodemus sylvaticus (32), Clethrionomys glareolus (29) and 4 individuals of insectivores – Sorex araneus. Apodemus flavicollis dominated in both types of stands. In the most numerous Apodemus flavicollis, body dimensions were compared between oak and beech stands; the differences were not significant. Species diversity (owing to the presence of Sorex araneus) is slightly higher in oak stands (diversity index H‘ = 1.60) as compared with beech stands (H‘ = 1.43). From the aspect of faunistic similarity, it is the case of very similar communities (Re = 97.3; I<sub>BC</sub> = 0.79). In all trapped individuals, basic body parameters were measured. In the oak forest, a higher total abundance was determined in all species as compared with the beech forest. Rodent populations responded to the poor crop of beechnuts and acorns in 2002 by a decline in numbers and to the good seed crop in 2003 by an increase in numbers (Apodemus spp.). Another response was the prolongation of reproduction period. In stomachs of the rodents caught in 2003 the percentage of starch granules of consumed food was superior to 2003.
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Voltura, Mary Beth. "Seasonal variation in body composition and gut capacity of the prairie vole (Microtus ochrogaster)." Canadian Journal of Zoology 75, no. 10 (October 1, 1997): 1714–19. http://dx.doi.org/10.1139/z97-798.
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Prairie voles (Microtus ochrogaster) were trapped during different seasons in order to examine simultaneous variation in body composition and gut capacity. Voles in reproductive condition were trapped in May, August, and November but not in February. Body masses of adult voles were lowest during February 1994. Adult males showed no seasonal variation in absolute lipid mass but did exhibit variation in relative fat content (percent body fat), with the highest values found in February 1994. Both absolute lipid mass and relative fat content of adult females varied with month of capture and were higher in February of both 1994 and 1995. Juvenile voles showed no variation in body composition between seasons and had fat levels similar to those of adult voles in the breeding months. Wet mass of the gastrointestinal tract varied with season of capture for both adult males and females, but no distinct pattern was evident. Mass of gut contents varied between trapping periods for adult males, but there were no seasonal differences in the gut contents of adult females or juveniles. The average mass of gut contents was higher than previously reported for field-caught prairie voles; this difference is likely due to the use of snap traps versus live traps.
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Côté, Mathieu, Jean Ferron, and Réjean Gagnon. "Impact of seed and seedling predation by small rodents on early regeneration establishment of black spruce." Canadian Journal of Forest Research 33, no. 12 (December 1, 2003): 2362–71. http://dx.doi.org/10.1139/x03-167.
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Black spruce (Picea mariana (Mill.) BSP) postdispersal seed and juvenile seedling predation by small rodents (Peromyscus maniculatus (Wagner), Clethrionomys gapperi (Vigor), and Phenacomys intermedius (Merriam)) was assessed in three boreal habitats over a 2-year period using an extensive exclosurecontrol experiment. Small rodent relative abundance was measured during six periods using snap trapping. We found that seed and juvenile seedling predation by small rodents varied according to habitat type and over time. Indeed, seed predation was higher in sprucemoss forests than in other habitats, notably during the winter of 2002. During this period, seedling predation was higher in recent burns. This period of higher seed and juvenile seedling predation corresponded to an increase in small rodent abundance in our study area. We suggest that seeds and juvenile seedlings can become important food sources for small rodents during winter when fresh and succulent vegetation is rare, as shown by results of seed predation. The impact of small rodents on the early regeneration of black spruce in the eastern Canadian boreal forest is thus an important factor to consider to better understand the forest regeneration process in this particular biome. Rodents can have a major effect on regeneration following a burn and can also contribute to poor seedling establishment from natural seed rain under mature cover.
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Krijger, Inge M., Gerrit Gort, Steven R. Belmain, Peter W. G. Groot Koerkamp, Rokeya B. Shafali, and Bastiaan G. Meerburg. "Efficacy of Management and Monitoring Methods to Prevent Post-Harvest Losses Caused by Rodents." Animals 10, no. 9 (September 9, 2020): 1612. http://dx.doi.org/10.3390/ani10091612.
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The presence of pest rodents around food production and storage sites is one of many underlying problems contributing to food contamination and loss, particularly influencing food and nutrition security in low-income countries. By reducing both pre- and post-harvest losses by rodents, millions of food-insecure people would benefit. As there are limited quantitative data on post-harvest rice losses due to rodents, our objectives were to assess stored rice losses in local households from eight rural communities and two rice milling factories in Bangladesh and to monitor the effect of different rodent control strategies to limit potential losses. Four treatments were applied in 2016 and 2017, (i) untreated control, (ii) use of domestic cats, (iii) use of rodenticides, (iv) use of snap-traps. In total, over a two-year period, 210 rodents were captured from inside people’s homes, with Rattus rattus trapped most often (n = 91), followed by Mus musculus (n = 75) and Bandicota bengalensis (n = 26). In the milling stations, 68 rodents were trapped, of which 21 were M. musculus, 19 R. rattus, 17 B. bengalensis, 8 Rattus exulans, and 3 Mus terricolor. In 2016, losses from standardised baskets of rice within households were between 13.6% and 16.7%. In 2017, the losses were lower, ranging from 0.6% to 2.2%. Daily rodent removal by trapping proved to be most effective to diminish stored produce loss. The effectiveness of domestic cats was limited.
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Bidhendi, Mehrnoosh Moradi, Griselda Garcia-Olvera, Brendon Morin, John S. Oakey, and Vladimir Alvarado. "Interfacial Viscoelasticity of Crude Oil/Brine: An Alternative Enhanced-Oil-Recovery Mechanism in Smart Waterflooding." SPE Journal 23, no. 03 (January 9, 2018): 803–18. http://dx.doi.org/10.2118/169127-pa.
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Summary Injection of water with a designed chemistry has been proposed as a novel enhanced-oil-recovery (EOR) method, commonly referred to as low-salinity (LS) or smart waterflooding, among other labels. The multiple names encompass a family of EOR methods that rely on modifying injection-water chemistry to increase oil recovery. Despite successful laboratory experiments and field trials, underlying EOR mechanisms remain controversial and poorly understood. At present, the vast majority of the proposed mechanisms rely on rock/fluid interactions. In this work, we propose an alternative fluid/fluid interaction mechanism (i.e., an increase in crude-oil/water interfacial viscoelasticity upon injection of designed brine as a suppressor of oil trapping by snap-off). A crude oil from Wyoming was selected for its known interfacial responsiveness to water chemistry. Brines were prepared with analytic-grade salts to test the effect of specific anions and cations. The brines’ ionic strengths were modified by dilution with deionized water to the desired salinity. A battery of experiments was performed to show a link between dynamic interfacial viscoelasticity and recovery. Experiments include double-wall ring interfacial rheometry, direct visualization on microfluidic devices, and coreflooding experiments in Berea sandstone cores. Interfacial rheological results show that interfacial viscoelasticity generally increases as brine salinity is decreased, regardless of which cations and anions are present in brine. However, the rate of elasticity buildup and the plateau value depend on specific ions available in solution. Snap-off analysis in a microfluidic device, consisting of a flow-focusing geometry, demonstrates that increased viscoelasticity suppresses interfacial pinch-off, and sustains a more continuous oil phase. This effect was examined in coreflooding experiments with sodium sulfate brines. Corefloods were designed to limit wettability alteration by maintaining a low temperature (25°C) and short aging times. Geochemical analysis provided information on in-situ water chemistry. Oil-recovery and pressure responses were shown to directly correlate with interfacial elasticity [i.e., recovery factor (RF) is consistently greater the larger the induced interfacial viscoelasticity for the system examined in this paper]. Our results demonstrate that a largely overlooked interfacial effect of engineered waterflooding can serve as an alternative and more complete explanation of LS or engineered waterflooding recovery. This new mechanism offers a direction to design water chemistry for optimized waterflooding recovery in engineered water-chemistry processes, and opens a new route to design EOR methods.
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L. Major, Heather, and Ian L. Jones. "Distribution, biology and prey selection of the introduced Norway Rat Rattus norvegicus at Kiska Island, Aleutian Islands, Alaska." Pacific Conservation Biology 11, no. 2 (2005): 105. http://dx.doi.org/10.1071/pc050105.
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At Kiska Island, Alaska, USA we quantified age, sex, size, distribution and predation of Least Auklets Aethia pusilla by non-indigenous Norway Rats Rattus norvegicus, to evaluate their impact on auklet reproductive success. Rat distribution was assessed by surveying accessible parts of Kiska Island for rat sign and prey hoards. To quantify prey selection and infer diet, the contents of all hoards found were identified. Age, sex and size structure of the rat population was assessed using limited snap trapping on and off the Sirius Point auklet colony. Norway Rat sign was abundant in all areas near breeding seabirds and marine sources of food but rat sign abundance varied among years at Sirius Point. Although we found a larger proportion of juvenile to adult rats (0.54 : 0.46, p < 0.01) at Sirius Point, no significant differences were found in the proportion of reproductive to non-reproductive females (0.50 : 0.27, p > 0.05) or in overall adult body size (257 g and 37 cm : 236 g and 35 cm, p > 0.05) between Sirius Point and Christine Lake where breeding auklets are absent. Surplus killing and food hoarding by rats was noted in all years during the auklet laying period, with adult Least Auklets being the principal prey taken (4-148 individuals per hoard, n = 16 hoards). Our observations were consistent with the notion that rats have a negative impact on auklet populations, but for management purposes further information on whether rats are the sole cause of auklet reproductive failure is required.
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Mukhopadhyay, Somshuvra, Jason Lee, and Pravin B. Sehgal. "Depletion of the ATPase NSF from Golgi membranes with hypo-S-nitrosylation of vasorelevant proteins in endothelial cells exposed to monocrotaline pyrrole." American Journal of Physiology-Heart and Circulatory Physiology 295, no. 5 (November 2008): H1943—H1955. http://dx.doi.org/10.1152/ajpheart.00642.2008.
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Investigations of regulated S-nitrosylation and denitrosylation of vasorelevant proteins are a newly emergent area in vascular biology. We previously showed that monocrotaline pyrrole (MCTP)-induced megalocytosis of pulmonary arterial endothelial cells (PAECs), which underlies the development of pulmonary arterial hypertension, was associated with a Golgi blockade characterized by the trapping of diverse vesicle tethers, soluble N-ethylmaleimide-sensitive factor (NSF)-attachment protein receptors (SNAREs), and soluble NSF-attachment proteins (SNAPs) in the Golgi; reduced trafficking of caveolin-1 (cav-1) and endotheial nitric oxide (NO) synthase (eNOS) from the Golgi to the plasma membrane; and decreased caveolar NO. We have investigated whether NSF, the ATPase involved in all SNARE disassembly, might be the upstream target of MCTP and whether MCTP might regulate NSF by S-nitrosylation. Immunofluorescence microscopy and Golgi purification techniques revealed the discordant decrease of NSF by ∼50% in Golgi membranes after MCTP despite increases in α-SNAP, cav-1, eNOS, and syntaxin-6. The NO scavenger (4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide failed to affect the initiation or progression of MCTP megalocytosis despite a reduction of 4,5-diaminofluorescein diacetate fluorescence and inhibition of S-nitrosylation of eNOS as assayed using the biotin-switch method. Moreover, the latter assay not only revealed constitutive S-nitrosylation of NSF, eNOS, cav-1, and clathrin heavy chain (CHC) in PAECs but also a dramatic 70–95% decrease in the S-nitrosylation of NSF, eNOS, cav-1, and CHC after MCTP. These data point to depletion of NSF from Golgi membranes as a mechanism for Golgi blockade after MCTP and to denitrosylation of vasorelevant proteins as critical to the development of endothelial cell megalocytosis.
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Wondifraw, Bewketu Takele, Mesele Yihune Tamene, and Afework Bekele Simegn. "Assessment of crop damage by rodent pests from experimental barley crop fields in Farta District, South Gondar, Ethiopia." PLOS ONE 16, no. 8 (August 12, 2021): e0255372. http://dx.doi.org/10.1371/journal.pone.0255372.
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This study was conducted in Farta district, south Gondar from 2019 to 2020 cropping years to identify rodent pest species and estimate damage caused on barley crops. Four independent barley crop fields (40 x 40 m each) were sampled randomly to estimate the loss. Two were located near Alemsaga Priority State Forest and the other two were away from the forest. Four (2 x 2 m) rodent exclusion plots were established at 10 m interval as control units in each selected experimental barley fields using fine wire mesh. Rodent pest species were collected using both Sherman and snap traps throughout the different crop growing stages. The damaged and undamaged barley tillers by pest rodents were counted on five 1 x 1 m randomly sampled quadrats for each selected experimental fields. Variations on pest rodent population between cropping years and sites were analyzed using Chi square test. The mean crop damages between cropping years and experimental field sites were analyzed using two way ANOVA. Arvicanthis abyssinicus, Mastomys natalensis, Arvicanthis dembeensis, Mus musculus, Lophuromys simensis, Tachyoryctes splendens and Hystrix cristata were identified as pest rodents in the study area. A total of 968 individual rodents (427 in 2019 and 541 in 2020) were trapped during the study period. There was a statistical variation (χ2 = 13.42, df = 1 and P<0.05) between trapped individuals of the two successive years. The crop fields near the forest were more vulnerable than away from the forest during both cropping years. Statistical variations was observed on mean crop losses between cropping years and experimental barley crop sites. The highest crop damage was seen at maturity stage and the lowest during sowing in all experimental plots and cropping years. The percentage of barley yield loss due to rodent pests was 21.7 kg ha-1. The monetary value of this yield loss was equivalent to 4875 Birr (121.9 US$ h-1). Alemsaga Forest as shelter and conservation strategies like free of farmland from livestock and terracing for soil conservation have great role for the high rodent pest populations in the study area. Field sanitation, trapping and using restricted rodenticides like zinc phosphide are the possible recommendation to local farmers against rodent pests.
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My Phung, Nguyen Thi, Peter R. Brown, and Luke K. P. Leung. "The diet of the female ricefield rat, Rattus argentiventer, influences their breeding performance in a mixed rice cropping ecosystem in An Giang province, the Mekong Delta, Vietnam." Wildlife Research 38, no. 7 (2011): 610. http://dx.doi.org/10.1071/wr10180.
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Context The ricefield rat, Rattus argentiventer, is the main rodent pest of rice in Vietnam, causing annual pre-harvest rice losses of around 10%. Although its diet is reported to consist of mainly rice, other components might also be important, and it is not known whether its breeding performance is affected by the quality and/or quantity of food. Furthermore, if its breeding is synchronised with the growth of rice crops, the rats will be able to make full use of the food supply to produce offspring. This knowledge is necessary for developing improved strategies for managing this pest. Aims This study aimed to determine whether the breeding performance of female R. argentiventer is responding to food quality (increased percentage of rice in stomach) and/or quantity (increased weight of stomach content) or whether its breeding is synchronised with the growth of rice crops. Methods The stomach contents and breeding condition of 296 adult female rats were sampled by snap trapping once a month from October 2008 to December 2009 over three consecutive irrigated lowland rice crops fields to cover a range of rice growth stages in An Giang province, Mekong Delta, Vietnam. Key results Overall, rice formed 70.5% ± 2.0 s.e. in the diet, followed by green material (25.9% ± 1.9 s.e.), insects (3.1% ± 0.6 s.e.) and mung bean (0.5% ± 0.3 s.e.). The probability of breeding increased with increasing mean percentage of rice in the diet: Pr(Breed) = 1/(1 + exp(0.6395–0.0090 × Rice)). However, this relationship was not consistent because breeding performance was high at the heading stage when the percentage of rice in the stomach was low and because breeding intensity was low at sowing when the percentage of rice in stomach was high. The rice growth stage is a better predictor for the breeding performance than the percentage of rice in the diet. Conclusions Breeding was driven by a functional response of rats to the abundant supply of food quality (rice grain), modified by some unknown mechanisms that modifies this response of rats so that rats can anticipate food supply. Understanding the nature of this mechanism may provide insights into population processes that can be exploited in controlling rats in rice crops. Implications Farmers could slow the reproductive rate of female R. argentiventer by reducing the food quantity through minimising the amount of spilt grain left in the field and through more synchronous cropping.
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Dyer, Brendan C., Anthony R. Clarke, and Susan J. Fuller. "Population dynamics, diet and pest status of the grassland melomys (Melomys burtoni) in northern Queensland sugarcane crops." Wildlife Research 38, no. 4 (2011): 330. http://dx.doi.org/10.1071/wr10171.
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Context In far-northern Queensland, Melomys burtoni and M. cervinipes occur within sugarcane crops and adjacent habitats and are potentially damaging to sugarcane. Aims To examine the population dynamics and diet of Melomys spp. within sugarcane crops so that, in conjunction with cane-stalk damage assessments, their pest status could be determined and information provided relevant to the development of sustainable pest-management tools. Methods Eight sites within sugarcane fields, four adjacent to grassland and four adjacent to closed forest, were established around Tully in far-northern Queensland. We examined demographic characteristics of all rodents (the two Melomys spp. and Rattus sordidus) within the crops by capture–release studies. Snap-trapping and dissection studies, along with weed-biomass surveys, were conducted for diet analysis, whereas damaged stalk counts were undertaken to understand the damage process. Fieldwork commenced within a fully developed crop, then continued through the annual harvest period and all subsequent crop growth stages to the next harvest. Sampling was undertaken monthly from February 2005 to April 2006. Key results Melomys cervinipes was rarely caught in sugarcane and should not be regarded as a pest. In contrast, M. burtoni feeds on sugarcane and was responsible for damage to ~6% of stalks. In sites adjacent to closed forest, R. sordidus was found in higher numbers than was M. burtoni in Crop stages 2–4. However, at sites adjacent to grassland, numbers of M. burtoni increased in Crop stage 4, and before crop harvest, M. burtoni was found in higher numbers than was R. sordidus. M. burtoni colonised sugarcane at later stages of crop development than did R. sordidus. Although the level of M. burtoni reproduction was lower than that of R. sordidus, the highest proportion of pregnant M. burtoni individuals occurred during the later stages of crop development, corresponding directly with the highest proportion of juvenile recruitment. Conclusions Of the two Melomys species found in northern Queensland sugarcane crops, only M. burtoni should be regarded as a pest. This rodent breeds and feeds within the crop, primarily after canopy closure. M. burtoni captures were roughly equivalent irrespective of adjacent habitat type, whereas R. sordidus, the traditionally recognised major pest of sugarcane crops, was found in significantly higher numbers in sugarcane adjacent to closed forest. Implications The integrated pest-management (IPM) strategy developed for R. sordidus is centred on the early stages of crop development and includes population monitoring, in-crop weed control, harbourage management and strategic use of permitted rodenticides. The late colonisation and lower breeding potential of M. burtoni mean that the IPM strategy for R. sordidus will not be directly transferable to M. burtoni.
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Shams, Mosayeb, Kamaljit Singh, Branko Bijeljic, and Martin J. Blunt. "Direct Numerical Simulation of Pore-Scale Trapping Events During Capillary-Dominated Two-Phase Flow in Porous Media." Transport in Porous Media 138, no. 2 (May 28, 2021): 443–58. http://dx.doi.org/10.1007/s11242-021-01619-w.
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AbstractThis study focuses on direct numerical simulation of imbibition, displacement of the non-wetting phase by the wetting phase, through water-wet carbonate rocks. We simulate multiphase flow in a limestone and compare our results with high-resolution synchrotron X-ray images of displacement previously published in the literature by Singh et al. (Sci Rep 7:5192, 2017). We use the results to interpret the observed displacement events that cannot be described using conventional metrics such as pore-to-throat aspect ratio. We show that the complex geometry of porous media can dictate a curvature balance that prevents snap-off from happening in spite of favourable large aspect ratios. We also show that pinned fluid-fluid-solid contact lines can lead to snap-off of small ganglia on pore walls; we propose that this pinning is caused by sub-resolution roughness on scales of less than a micron. Our numerical results show that even in water-wet porous media, we need to allow pinned contacts in place to reproduce experimental results.
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Poppinga, Simon, and Marc Joyeux. "Different mechanics of snap-trapping in the two closely related carnivorous plantsDionaea muscipulaandAldrovanda vesiculosa." Physical Review E 84, no. 4 (October 24, 2011). http://dx.doi.org/10.1103/physreve.84.041928.
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Adebayo, Abdulrauf Rasheed. "Foam Flow in Different Pore Systems—Part 1: The Roles of Pore Attributes and Their Variation on Trapping and Apparent Viscosity of Foam." SPE Journal, August 1, 2021, 1–18. http://dx.doi.org/10.2118/206719-pa.
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Summary Lateral propagation of foam in heterogeneous reservoirs, where pore geometries vary laterally, depends on the roles of pore geometries on the foam properties. In this paper, the pore attributes of 12 different rock samples were characterized in terms of porosity, permeability, pore shape, pore size, throat size, aspect ratio, coordination number, and log mean of surface relaxation times (T2LM). These were measured from gas porosimeter and permeameter, X-ray microcomputed tomography (CT)-basedpore-network models, thin-section photomicrographs, and nuclear magnetic resonance (NMR) surface relaxometry. The samples have a wide range of porosity: 12 to 29%; permeability: 1 to 5,000 md; average pore size: 3.7 to 9 µm; average throat size: 2.4 to 8 µm; average aspect ratio: 1 to 1.7; average coordination number: 2.6 to 5.2; and T2LM: 9.4 to 740 ms. Nitrogen foam flow experiments (without oil) were then conducted on each rock sample using a specialized coreflood apparatus. A graphical analysis of the coreflood data was used to estimate the total saturation of trapped foam (10 to 66%), flowing foam (3 to 14%), and apparent viscosity of foam (3.2 to 73 cp). Trapped foam saturation and apparent viscosity values were then correlated with each of the measured pore attributes. The results revealed that all pore attributes, except aspect ratio, have positive correlations with foam trapping and apparent viscosity. The best correlation with trapped foam saturation was obtained when the most influential pore attributes (pore size, throat size, aspect ratio, and coordination number) were combined into a single mathematical function. Foam apparent viscosity also appears to be mostly influenced by trapped foam saturation, permeability, and coordination number of pore systems. Trapping is also likely enhanced by the presence of fenestral or channel pores. Furthermore, the shape and angularity of pores seem to facilitate snap-off and trapping of foam, because rock samples with angular pores trapped the highest foam saturation compared with other samples with rounded and subrounded pores. It was also shown that the correlation between trapped foam saturation (and foam apparent viscosity) and the absolute permeability of porous media may reverse at some high-permeability values (greater than several darcies), when one or both of the following conditions exist: (1) The aspect ratio of a lower-permeability porous medium is lower than that of a higher-permeability porous medium, and (2) the coordination number of a lower-permeability porous medium is higher than that of a higher-permeability porous medium. Finally, T2LM showed a good correlation with foam trapping, making NMR logging a prospective tool for pre-evaluating foam performance in targeted reservoir sections.
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Shiels, Aaron ,. B., Tyler Bogardus, Jobriath Rohrer, and Kapua Kawelo. "Effectiveness of Snap-trapping, Goodnature A24 Automated Traps, and Hand-broadcast of Diphacinone Anticoagulant Baits to Suppress Invasive Rats (Rattus spp.) and Mice (Mus musculus) in Hawaiian Forest." Proceedings of the Vertebrate Pest Conference 28 (2018). http://dx.doi.org/10.5070/v42811009.
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Maragliano, C., D. Heskes, M. Stefancich, M. Chiesa, and T. Souier. "High resolution dynamic electrostatic force microscopy technique: quantifying electrical properties at the nanoscale." MRS Proceedings 1652 (2014). http://dx.doi.org/10.1557/opl.2014.291.
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AbstractIn electrostatic force microscopy (EFM), a conductive atomic force microscopy (AFM) tip is electrically biased against a grounded sample and electrostatic forces are investigated. This methodology has been broadly used in the scientific community to characterize dielectric properties of samples at the nanoscale. Two are the main operating conditions associated with this technique. The oscillation amplitude is usually kept to very small values to allow a linearized approach to the force reconstruction and the tip-sample distance is maintained elevated. However, this latter condition negatively affects the lateral resolution of the technique. Thus, electrostatic interaction should be probed in the vicinity of the sample. Theoretically, in this region the force can be linearized using oscillation amplitudes in the order of Å. This might cause the trapping of the tip on the surface (snap-in). Furthermore, at small distances, short-range forces (i.e. Van der Waals’) might reach values comparable to electrostatic forces.Here we present a framework that combines EFM and dynamic amplitude modulation AFM to achieve decoupled reconstruction of forces. It permits reconstructing the real shape of the electrostatic force and the capacitance of the tip-sample system even in the vicinity of the surface. This is done using a technique proposed in literature by Sader and Katan to reconstruct the force without the linearization approximation. The steps needed to decouple short-range and electrostatic forces are explained in detail. This data can be employed to derive the electrical properties of thin films with enhanced lateral resolution with respect to the commonly used EFM techniques.
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Horstmann, M., L. Heier, S. Kruppert, L. C. Weiss, R. Tollrian, L. Adamec, A. Westermeier, T. Speck, and S. Poppinga. "Comparative Prey Spectra Analyses on the Endangered Aquatic Carnivorous Waterwheel Plant (Aldrovanda vesiculosa, Droseraceae) at Several Naturalized Microsites in the Czech Republic and Germany." Integrative Organismal Biology 1, no. 1 (January 1, 2019). http://dx.doi.org/10.1093/iob/oby012.
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Synopsis The critically endangered carnivorous waterwheel plant (Aldrovanda vesiculosa, Droseraceae) possesses underwater snap traps for capturing small aquatic animals, but knowledge on the exact prey species is limited. Such information would be essential for continuing ecological research, drawing conclusions regarding trapping efficiency and trap evolution, and eventually, for conservation. Therefore, we performed comparative trap size measurements and snapshot prey analyses at seven Czech and one German naturalized microsites on plants originating from at least two different populations. One Czech site was sampled twice during 2017. We recorded seven main prey taxonomic groups, that is, Cladocera, Copepoda, Ostracoda, Ephemeroptera, Nematocera, Hydrachnidia, and Pulmonata. In total, we recorded 43 different prey taxa in 445 prey-filled traps, containing in sum 461 prey items. With one exception, prey spectra did not correlate with site conditions (e.g. water depth) or trap size. Our data indicate that A. vesiculosa shows no prey specificity but catches opportunistically, independent of prey species, prey mobility mode (swimming or substrate-bound), and speed of movement. Even in cases where the prey size exceeded trap size, successful capture was accomplished by clamping the animal between the traps’ lobes. As we found a wide prey range that was attracted, it appears unlikely that the capture is enhanced by specialized chemical- or mimicry-based attraction mechanisms. However, for animals seeking shelter, a place to rest, or a substrate to graze on, A. vesiculosa may indirectly attract prey organisms in the vicinity, whereas other prey capture events (like that of comparably large notonectids) may also be purely coincidental.