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1
Musgrave, Stephanie, Elizabeth Lonsdorf, David Morgan, Madison Prestipino, Laura Bernstein-Kurtycz, Roger Mundry, and Crickette Sanz. "Teaching varies with task complexity in wild chimpanzees." Proceedings of the National Academy of Sciences 117, no. 2 (December 23, 2019): 969–76. http://dx.doi.org/10.1073/pnas.1907476116.
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Cumulative culture is a transformative force in human evolution, but the social underpinnings of this capacity are debated. Identifying social influences on how chimpanzees acquire tool tasks of differing complexity may help illuminate the evolutionary origins of technology in our own lineage. Humans routinely transfer tools to novices to scaffold their skill development. While tool transfers occur in wild chimpanzees and fulfill criteria for teaching, it is unknown whether this form of helping varies between populations and across tasks. Applying standardized methods, we compared tool transfers during termite gathering by chimpanzees in the Goualougo Triangle, Republic of Congo, and in Gombe, Tanzania. At Goualougo, chimpanzees use multiple, different tool types sequentially, choose specific raw materials, and perform modifications that improve tool efficiency, which could make it challenging for novices to manufacture suitable tools. Termite gathering at Gombe involves a single tool type, fishing probes, which can be manufactured from various materials. Multiple measures indicated population differences in tool-transfer behavior. The rate of transfers and probability of transfer upon request were significantly higher at Goualougo, while resistance to transfers was significantly higher at Gombe. Active transfers of tools in which possessors moved to facilitate possession change upon request occurred only at Goualougo, where they were the most common transfer type. At Gombe, tool requests were typically refused. We suggest that these population differences in tool-transfer behavior may relate to task complexity and that active helping plays an enhanced role in the cultural transmission of complex technology in wild apes.
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Jaramillo, Nacarí, Esteban Domingo, María Carmen Muñoz-Egea, Enrique Tabarés, and Ignacio Gadea. "Evidence of Muller’s ratchet in herpes simplex virus type 1." Journal of General Virology 94, no. 2 (February 1, 2013): 366–75. http://dx.doi.org/10.1099/vir.0.044685-0.
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Population bottlenecks can have major effects in the evolution of RNA viruses, but their possible influence in the evolution of DNA viruses is largely unknown. Genetic and biological variation of herpes simplex virus type 1 (HSV-1) has been studied by subjecting 23 biological clones of the virus to 10 plaque-to-plaque transfers. In contrast to large population passages, plaque transfers led to a decrease in replicative capacity of HSV-1. Two out of a total of 23 clones did not survive to the last transfer in 143 TK– cells. DNA from three genomic regions (DNA polymerase, glycoprotein gD and thymidine kinase) from the initial and passaged clones was sequenced. Nucleotide substitutions were detected in the TK and gD genes, but not in the DNA polymerase gene. Assuming a uniform distribution of mutations along the genome, the average rate of fixation of mutations was about five mutations per viral genome and plaque transfer. This value is comparable to the range of values calculated for RNA viruses. Four plaque-transferred populations lost neurovirulence for mice, as compared with the corresponding initial clones. LD50 values obtained with the populations subjected to serial bottlenecks were 4- to 67-fold higher than for their parental clones. These results equate HSV-1 with RNA viruses regarding fitness decrease as a result of plaque–to-plaque transfers, and show that population bottlenecks can modify the pathogenic potential of HSV-1. Implications for the evolution of complex DNA viruses are discussed.
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Murray, Clyde B., and Terry D. Beacham. "Responses of meristic characters in chum salmon (Oncorhynchus keta) to temperature changes during development." Canadian Journal of Zoology 67, no. 3 (March 1, 1989): 596–600. http://dx.doi.org/10.1139/z89-086.
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Variability in the number of dorsal, anal, caudal, pectoral, and pelvic fin rays, vertebrae, and gill rakers was examined in four populations of chum salmon (Oncorhynchus keta) transferred from 8 to 2 °C at various stages of embryonic development. Late transfers at complete eye pigmentation produced more gill rakers than transfers earlier in development. Transfers at completion of epiboly and initial eye pigmentation produced fewer vertebrae than earlier or later transfers. Stage of transfer had no significant effect on fin ray counts. Vertebral responses differed among families. Genotype–environment interactions produce meristic phenotypes that are presently difficult to predict.
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Steinberg, Jessica. "Strategic Sovereignty." Journal of Conflict Resolution 60, no. 8 (July 11, 2016): 1503–28. http://dx.doi.org/10.1177/0022002714564429.
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In some regions of natural resource extraction, embedded local populations receive transfers that compensate them for environmental consequences of extraction; while in others, these populations receive no benefits and endure negative environmental externalities, which can lead to violent protest. This article develops a formal model of the strategic dynamics among a government, a natural resource extraction firm, and a local population in an extractive region to understand the variation in extractive outcomes. The model specifies the conditions under which firms will provide promised transfers to a local population, distributive conflict will occur, and how the government will respond.
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McMechan, Anthony J., Satyanarayana Tatineni, Roy French, and Gary L. Hein. "Differential Transmission of Triticum mosaic virus by Wheat Curl Mite Populations Collected in the Great Plains." Plant Disease 98, no. 6 (June 2014): 806–10. http://dx.doi.org/10.1094/pdis-06-13-0582-re.
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Wheat is an important food grain worldwide and the primary dryland crop in the western Great Plains. A complex of three wheat curl mite (WCM)-transmitted viruses (Wheat streak mosaic virus, High plains virus, and Triticum mosaic virus [TriMV]) is a cause of serious loss in winter wheat production in the Great Plains. TriMV was first reported in Kansas in 2006 and later found in most other Great Plains states. Currently, three populations of WCM have been identified by genetic characterization and differential responses to mite resistance genes in wheat. In this study, we examined TriMV transmission by these three WCM populations: ‘Nebraska’ (NE), ‘Montana’ (MT), and ‘South Dakota’ (SD). Mite transmission using single-mite transfers revealed that the NE WCM population transmitted TriMV at 41%, while the MT and SD WCM populations failed to transmit TriMV. In multi-mite transfers, the NE WCM population transmitted TriMV at 100% level compared with 2.5% transmission by MT and SD WCM populations. Interestingly, NE mites transferred during the quiescent stages following the first and second instar transmitted TriMV at a 39 to 40% rate, suggesting that immature mites were able to acquire the virus and maintain it through molting. In addition, mite survival for single-mite transfers was significantly lower for NE mites when transferred from TriMV-inoculated source plants (60%) compared with mock-inoculated source plants (84%). This demonstrates potentially negative effects on WCM survival from TriMV. TriMV transmission differences demonstrated in this study underscore the importance of identification of mite genotypes for future studies with TriMV.
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Komdeur, Jan. "Inter-island transfers and population dynamics of Seychelles Warblers Acrocephalus sechellensis." Bird Conservation International 7, no. 1 (March 1997): 7–26. http://dx.doi.org/10.1017/s0959270900001374.
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SummaryIn the 1950s the Seychelles Warbler Acrocephalus sechellensis was a highly threatened single-island endemic species with a population of 26 individuals confined to Cousin Island in the inner Seychelles. Following long-term management of Cousin, the population steadily recovered to around 300–360 birds. In order to give the species the security of additional breeding populations, some warblers were successfully transferred to the islands of Aride and Cousine in September 1988 and June 1990 respectively. During the three years after the transfer to Aride and the first year after the transfer to Cousine, mean territory quality (measured as insect prey available) on these islands was significantly higher than that on Cousin, leading to higher reproductive success per territory and survival of juveniles and adult birds. In November 1991, all transferred birds were still alive, and 205 young had fledged successfully, bringing the total warbler population to c.585 birds. By then there was enough suitable space still remaining on Aride and Cousine for young birds to establish territories and the rise in warbler numbers is expected to continue. The successful establishment of three self-sustaining and viable breeding populations has ensured that the Seychelles Warbler is no longer a globally threatened species.
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Izquierdo, Jorge I., Ana G. F. Castillo, Fernando Ayllon, Jeronimo de la Hoz, and Eva Garcia-Vazquez. "Stock Transfers in Spanish Brown Trout Populations: A Long-term Assessment." Environmental Biology of Fishes 75, no. 2 (February 2006): 153–57. http://dx.doi.org/10.1007/s10641-005-5068-1.
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Power, Jeffrey J., Fernanda Pinheiro, Simone Pompei, Viera Kovacova, Melih Yüksel, Isabel Rathmann, Mona Förster, Michael Lässig, and Berenike Maier. "Adaptive evolution of hybrid bacteria by horizontal gene transfer." Proceedings of the National Academy of Sciences 118, no. 10 (March 1, 2021): e2007873118. http://dx.doi.org/10.1073/pnas.2007873118.
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Horizontal gene transfer (HGT) is an important factor in bacterial evolution that can act across species boundaries. Yet, we know little about rate and genomic targets of cross-lineage gene transfer and about its effects on the recipient organism's physiology and fitness. Here, we address these questions in a parallel evolution experiment with two Bacillus subtilis lineages of 7% sequence divergence. We observe rapid evolution of hybrid organisms: gene transfer swaps ∼12% of the core genome in just 200 generations, and 60% of core genes are replaced in at least one population. By genomics, transcriptomics, fitness assays, and statistical modeling, we show that transfer generates adaptive evolution and functional alterations in hybrids. Specifically, our experiments reveal a strong, repeatable fitness increase of evolved populations in the stationary growth phase. By genomic analysis of the transfer statistics across replicate populations, we infer that selection on HGT has a broad genetic basis: 40% of the observed transfers are adaptive. At the level of functional gene networks, we find signatures of negative, positive, and epistatic selection, consistent with hybrid incompatibilities and adaptive evolution of network functions. Our results suggest that gene transfer navigates a complex cross-lineage fitness landscape, bridging epistatic barriers along multiple high-fitness paths.
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Smuel, Lvončík, Maděra Petr, Volařík Daniel, Vrškový Boris, and Habrová Hana. "First Proposal Of Seed Regions For Frankincense Trees (Boswellia Spp.) On Socotra Island." Journal of Landscape Ecology 6, no. 3 (December 1, 2013): 35–45. http://dx.doi.org/10.2478/jlecol-2014-0002.
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Abstract The landscape differentiation on seed regions is used in the Czech forestry industry for purposes of seed transfers. The seed regions are created for main commercial tree species and the rules for transfer among these regions are described. The geobiocoenological landscape differentiation and differences among tree species populations were used as main approaches. The same principle is used for Boswellia seed regions differentiation on Socotra island. Eight species of Boswellia genus were determined on the island, all species being endemic. The differentiation is based on Boswellia populations field survey. All populations were described in morphological signs. The vegetation zones and geomorphological differentiation were also taken into account. The result is a map of seed regions for every Boswellia species on Socotra island presented in the article.
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Quaranta, Luciana. "Program for Studying Intergenerational Transmissions in Infant Mortality Using the Intermediate Data Structure (IDS)." Historical Life Course Studies 7 (May 24, 2018): 11–27. http://dx.doi.org/10.51964/hlcs9287.
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Studies conducted in historical populations and developing countries have evidenced the existence of clustering in infant deaths, which could be related to genetic inheritance and/or to social and cultural factors such as education, socioeconomic status or parental care. A transmission of death clustering has also been found across generations. One way of expanding the knowledge on intergenerational transfers in infant mortality is by conducting comparable studies across different populations. The Intermediate Data Structure (IDS) was developed as a strategy aimed at simplifying the collecting, storing and sharing of historical demographic data. The current work presents two programs that were developed in STATA to construct a dataset for analysis and run statistical models to study intergenerational transfers in infant mortality using databases that are stored in the IDS. The programs use information stored in the IDS tables and after elaborating such information produce Excel files with results. They can be used with any longitudinal database constructed from church books, civil registers, or population registers.
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Brown, Gillian R. "Tolerated scrounging in nonhuman primates." Behavioral and Brain Sciences 27, no. 4 (August 2004): 562–63. http://dx.doi.org/10.1017/s0140525x04240122.
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Gurven suggests that the tolerated scrounging model has limited relevance for explaining patterns of food transfers in human populations. However, this conclusion is based on a restricted interpretation of the tolerated scrounging model proposed originally by Blurton Jones (1987). Examples of food transfers in nonhuman primates illustrate that the assumptions of Gurven's tolerated scrounging model are open to question.
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Kramer, Karen L. "Intergenerational transfers and the cost of allomothering in traditional societies." Behavioral and Brain Sciences 33, no. 1 (February 2010): 30–31. http://dx.doi.org/10.1017/s0140525x09991683.
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AbstractThe question of why helpers help is debated in the cooperative breeding literature. Recent reevaluations of inclusive fitness theory have important implications for traditional populations in which the provisioning of young occurs in the context of intergenerational transfers. These transfers link older and younger generations in an economic relationship that both minimizes the demand for help and the cost of helping.
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Bergmeister, Konstantin D., Martin Aman, Silvia Muceli, Ivan Vujaklija, Krisztina Manzano-Szalai, Ewald Unger, Ruth A. Byrne, et al. "Peripheral nerve transfers change target muscle structure and function." Science Advances 5, no. 1 (January 2019): eaau2956. http://dx.doi.org/10.1126/sciadv.aau2956.
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Selective nerve transfers surgically rewire motor neurons and are used in extremity reconstruction to restore muscle function or to facilitate intuitive prosthetic control. We investigated the neurophysiological effects of rewiring motor axons originating from spinal motor neuron pools into target muscles with lower innervation ratio in a rat model. Following reinnervation, the target muscle’s force regenerated almost completely, with the motor unit population increasing to 116% in functional and 172% in histological assessments with subsequently smaller muscle units. Muscle fiber type populations transformed into the donor nerve’s original muscles. We thus demonstrate that axons of alternative spinal origin can hyper-reinnervate target muscles without loss of muscle force regeneration, but with a donor-specific shift in muscle fiber type. These results explain the excellent clinical outcomes following nerve transfers in neuromuscular reconstruction. They indicate that reinnervated muscles can provide an accurate bioscreen to display neural information of lost body parts for high-fidelity prosthetic control.
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Im, Soobin, Da Young Lim, Min Kyun Sohn, and Yeongwook Kim. "Frequency of and Reasons for Unplanned Transfers From the Inpatient Rehabilitation Facility in a Tertiary Hospital." Annals of Rehabilitation Medicine 44, no. 2 (April 30, 2020): 151–57. http://dx.doi.org/10.5535/arm.2020.44.2.151.
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Objective To characterize the patients in the inpatient rehabilitation facility who were transferred to acute care facilities and identify the frequency of and reasons for the unplanned transfer.Methods Medical records of patients admitted to the inpatient rehabilitation facility from October 2017 to December 2018 were reviewed. Patients were categorized according to their diagnoses. The included patients were divided into the unplanned transfer and control groups based on whether they required to transfer to another department for acute care before completing an uninterrupted rehabilitation course. The groups were compared in terms of sex, age, length of stay, admission sources, and disease groups. The reasons for unplanned transfers were classified based on medical or surgical conditions.Results Of the 1,378 patients were admitted to the inpatient rehabilitation facility, 1,301 satisfied inclusion criteria. Among them, 121 (9.3%) were unexpectedly transferred to the medical or surgical department. The unplanned transfer group had a higher age (69.54±12.53 vs. 64.39±15.32 years; p=0.001) and longer length of stay (85.69±66.08 vs. 37.81±31.13 days; p<0.001) than the control group. The top 3 reasons for unplanned transfers were infectious disease, cardiopulmonary disease, and orthopedic problem.Conclusion The unplanned transfer group had a significantly higher age and longer length of stay. The most common reason for the unplanned transfer was infectious disease. However, the proportions of those with orthopedic and neurological problems were relatively high. Therefore, further studies of these patient populations may help organize systematic strategies that are needed to reduce unplanned transfers to acute facilities for patients in rehabilitation facilities.
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Wahl, Lindi M., Philip J. Gerrish, and Ivan Saika-Voivod. "Evaluating the Impact of Population Bottlenecks in Experimental Evolution." Genetics 162, no. 2 (October 1, 2002): 961–71. http://dx.doi.org/10.1093/genetics/162.2.961.
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AbstractExperimental evolution involves severe, periodic reductions in population size when fresh media are inoculated during serial transfer. These bottlenecks affect the dynamics of evolution, reducing the probability that a beneficial mutation will reach fixation. We quantify the impact of these bottlenecks on the evolutionary dynamics, for populations that grow exponentially between transfers and for populations in which growth is curbed by a resource-limited environment. We find that in both cases, mutations that survive bottlenecks are equally likely to occur, per unit time, at all times during the growth phase. We estimate the total fraction of beneficial mutations that are lost due to bottlenecks during experimental evolution protocols and derive the “optimal” dilution ratio, the ratio that maximizes the number of surviving beneficial mutations. Although more severe dilution ratios are often used in the literature, we find that a ratio of 0.1-0.2 minimizes the chances that rare beneficial mutations are lost. Finally, we provide a number of useful approximate results and illustrate our approach with applications to experimental evolution protocols in the literature.
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Hollingsworth, K. A., R. D. Shively, S. N. Glasscock, J. E. Light, D. R. Tolleson, and P. S. Barboza. "Trace mineral supplies for populations of little and large herbivores." PLOS ONE 16, no. 3 (March 15, 2021): e0248204. http://dx.doi.org/10.1371/journal.pone.0248204.
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Copper (Cu), iron (Fe), and zinc (Zn) are essential trace minerals for the reproduction, growth, and immunity of mammalian herbivore populations. We examined the relationships between Cu, Fe, and Zn in soils, common plants, and hepatic stores of two wild herbivores to assess the effects of weather, sex, and population density on the transfer of trace minerals from soils to mammals during the growing season. Soils, grasses, woody browse, hispid cotton rats (Sigmodon hispidus), and white-tailed deer (Odocoileus virginianus) were sampled across 19 sites. Concentrations of Cu, Fe, and Zn in grasses and browse species were not correlated with concentrations of those minerals in soils sampled from the same areas. Leaves of woody browse were higher in Cu, lower in Fe, and similar in Zn when compared with grasses. Available concentrations of soils were positively related to liver Cu and Zn in hispid cotton rats, which was consistent with the short lives and high productivity of these small mammals that rely on grass seed heads. Interactions between soil concentrations and weather also affected liver Cu and Fe in deer, which reflected the greater complexity of trophic transfers in large, long-lived, browsing herbivores. Population density was correlated with liver concentrations of Cu, Fe, and Zn in hispid cotton rats, and concentrations of Cu and Fe in deer. Liver Cu was < 5 mg/kg wet weight in at least 5% of animals at two of eight sites for hispid cotton rats and < 3.8 mg/kg wet weight in at least 5% of animals at three of 12 sites for deer, which could indicate regional limitation of Cu for populations of mammalian herbivores. Our data indicate that supplies of trace minerals may contribute to density dependence of herbivore populations. Local population density may therefore influence the prevalence of deficiency states and disease outbreak that exacerbate population cycles in wild mammals.
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Li, Haitao, Xianli Wang, and Andreas Hamann. "Genetic adaptation of aspen (Populus tremuloides) populations to spring risk environments: a novel remote sensing approach." Canadian Journal of Forest Research 40, no. 11 (November 2010): 2082–90. http://dx.doi.org/10.1139/x10-153.
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This study investigates geographic patterns of genetic variation in aspen (Populus tremuloides Michaux.) spring phenology with the aim of understanding adaptation of populations to climatic risk environments and the practical application of guiding seed transfer. We use a classical common garden experiment to reveal genetic differences among populations from western Canada and Minnesota, and we present a novel method to seamlessly map heat-sum requirements from remotely sensed green-up dates. Both approaches reveal similar geographic patterns: we find low heat-sum requirements in northern and high-elevation aspen populations, allowing them to take full advantage of a short growing season. High heat-sum requirements were found in populations from the central boreal plains of Saskatchewan and Alberta, and populations from Minnesota exhibit moderately low heat-sum requirements for budbreak. Analysis of corresponding climate normal data shows that late budbreak is strongly associated with the driest winter and spring environments, which suggests selection pressures for late budbreak due to both frost and drought risks in early spring. We therefore caution against long-distance seed transfer of Minnesota provenances to the boreal plains of Alberta and Saskatchewan. Although such transfers have been shown to increase tree growth in short-term field tests, this planting material may be susceptible to exceptional spring droughts.
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Ansolabehere, Stephen, Alan Gerber, and Jim Snyder. "Equal Votes, Equal Money: Court-Ordered Redistricting and Public Expenditures in the American States." American Political Science Review 96, no. 4 (December 2002): 767–77. http://dx.doi.org/10.1017/s0003055402000448.
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Court-ordered redistricting in the mid-1960s eradicated severe disparities in the populations of U.S. state legislative districts. We examine the geographic distribution of money by states to counties. Cross-sectional analysis shows that counties with relatively more legislativeseats per person prior to redistricting received relatively more transfers from the state per person. Over time, counties that lost legislative seats subsequently received a smaller share of state funds per capita. We calculate that population equalization significantly altered the flow of state transfers to counties, diverting approximately $7 billion annually from formerly overrepresented to formerly underrepresented counties, an effect missed by past studies. For those concerned with the design of democratic institutions around the world today, the American experience provides clear evidence of the political consequences of unequal representation.
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Herby, Peter. "Arms transfers, humanitarian assistance and international humanitarian law." International Review of the Red Cross 38, no. 325 (December 1998): 685–91. http://dx.doi.org/10.1017/s0020860400091567.
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The International Committee of the Red Cross has witnessed in its work for war victims throughout the world the increasingly devastating effects for civilian populations of the proliferation of weapons, particularly small arms. The difficulties of providing humanitarian assistance in an environment where arms have become widely available to many segments of society are well known to most humanitarian relief agencies today. However, until recently the relationships between the availability of weapons, the worsening situation of civilians during and after conflict and the challenges of providing humanitarian assistance have not been addressed directly.
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Lázaro, Ester, Cristina Escarmís, Esteban Domingo, and Susanna C. Manrubia. "Modeling Viral Genome Fitness Evolution Associated with Serial Bottleneck Events: Evidence of Stationary States of Fitness." Journal of Virology 76, no. 17 (September 1, 2002): 8675–81. http://dx.doi.org/10.1128/jvi.76.17.8675-8681.2002.
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ABSTRACT Evolution of fitness values upon replication of viral populations is strongly influenced by the size of the virus population that participates in the infections. While large population passages often result in fitness gains, repeated plaque-to-plaque transfers result in average fitness losses. Here we develop a numerical model that describes fitness evolution of viral clones subjected to serial bottleneck events. The model predicts a biphasic evolution of fitness values in that a period of exponential decrease is followed by a stationary state in which fitness values display large fluctuations around an average constant value. This biphasic evolution is in agreement with experimental results of serial plaque-to-plaque transfers carried out with foot-and-mouth disease virus (FMDV) in cell culture. The existence of a stationary phase of fitness values has been further documented by serial plaque-to-plaque transfers of FMDV clones that had reached very low relative fitness values. The statistical properties of the stationary state depend on several parameters of the model, such as the probability of advantageous versus deleterious mutations, initial fitness, and the number of replication rounds. In particular, the size of the bottleneck is critical for determining the trend of fitness evolution.
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Orr, Justin D., John C. Dunn, Kenneth A. Heida, Nicholas A. Kusnezov, Brian R. Waterman, and Philip J. Belmont. "Results and Functional Outcomes of Structural Fresh Osteochondral Allograft Transfer for Treatment of Osteochondral Lesions of the Talus in a Highly Active Population." Foot & Ankle Specialist 10, no. 2 (September 20, 2016): 125–32. http://dx.doi.org/10.1177/1938640016666924.
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Introduction. Structural fresh osteochondral allograft transfer is an appropriate treatment option for large osteochondral lesions of the talus (OLTs), specifically lesions involving the shoulder of the talus. Sparse literature exists regarding functional outcome following this surgery in high-demand populations. Materials and Methods. Over a 2-year period, a single surgeon performed 8 structural allograft transfers for treatment of large OLTs in an active duty US military population. Lesion morphology and magnetic resonance imaging (MRI) stage were recorded. Preoperative and latest postoperative American Orthopaedic Foot and Ankle Society (AOFAS) hindfoot-ankle and pain visual analog scores were compared. Results. Eight male service members with mean age 34.4 years underwent structural allograft transfer for OLTs with mean MRI stage of 4.9 and a mean lesion volume of 2247.1 mm3. Preoperative mean AOFAS hindfoot-ankle score was 49.6, and mean pain visual analog score was 6.9. At mean follow-up of 28.5 months, postoperative mean AOFAS score was 73, and mean pain visual analog score was 4.5, representing overall improvements of 47% and 35%, respectively. Three patients were considered treatment failures secondary to continued ankle disability (2) or graft resorption requiring ankle arthrodesis. Conclusions. Despite modest improvements in short-term functional outcome scores, large osteochondral lesions requiring structural allograft transfer remain difficult to treat, particularly in high-demand patient populations. Surgeons should counsel patients preoperatively on realistic expectations for return to function following structural allograft transfer procedures. Levels of Evidence: Level IV: Retrospective study
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Taylor, Eric B., and A. B. Costello. "Microsatellite DNA analysis of coastal populations of bull trout (Salvelinus confluentus) in British Columbia: zoogeographic implications and its application to recreational fishery management." Canadian Journal of Fisheries and Aquatic Sciences 63, no. 5 (May 1, 2006): 1157–71. http://dx.doi.org/10.1139/f06-026.
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Microsatellite DNA variation was assayed among 383 bull trout (Salvelinus confluentus) from 20 Pacific coastal localities from the Skeena River (central British Columbia) to the Olympic Peninsula (western Washington State). An average of 1.7 alleles was resolved per population and heterozygosity averaged 0.35. Twenty-six fish were identified as bull trout × Dolly Varden (Salvelinus malma) hybrids. Population subdivision was substantial (θ = 0.33), but subdivision was higher (θ = 0.46) when interior populations (N = 37) were included, indicating a major genetic distinction between "coastal" and "interior" bull trout. Bull trout populations north of the Squamish River were genetically more similar to interior bull trout than to other more southern coastal populations, suggesting that they had been founded by headwater transfers from interior populations. Individual assignment of bull trout averaged 53.4% correct assignment among populations (range: 12%95%). Mixture analysis indicated that most fish from the lower Fraser River recreational fishery originated from major nearby tributaries (e.g., Pitt, upper Lillooet, and Chilliwack rivers). Our results substantiate the existence of two major evolutionary lineages of bull trout and highlight the importance of tributary habitats for the persistence of local populations, as well as for those that forage in downstream areas on the lower Fraser River.
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Takamatsu, Mizuyo, and Azuma Taguchi. "Bus Timetable Design to Ensure Smooth Transfers in Areas with Low-Frequency Public Transportation Services." Transportation Science 54, no. 5 (September 2020): 1238–50. http://dx.doi.org/10.1287/trsc.2019.0918.
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This study investigates the timetable design problem in areas with low-frequency public transportation services. In Japan, rural areas face sparse populations and rapid growth in the percentage of elderly people. In these areas, many bus lines offer fewer than 10 services per day. In addition to low-frequency services, it is also inconvenient to transfer to another bus or train service. Thus, there is a strong need to design a timetable that ensures smooth transfers among buses and trains. We tackle this problem by adopting existing bus lines and train timetables as much as possible to avoid drastic changes such as an increase in the number of services. Based on this approach, we present a mathematical optimization model to generate a revised bus timetable that shortens waiting time for transfers compared with the current timetable. We apply our model to a part of the Tohoku District in Japan and demonstrate its usefulness in the real world.
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Rehfeldt, G. E. "Ecological Adaptations in Douglas-fir (Pseudotsuga menziesii var. glauca). IV. Montana and Idaho Near the Continental Divide." Western Journal of Applied Forestry 3, no. 4 (October 1, 1988): 101–5. http://dx.doi.org/10.1093/wjaf/3.4.101.
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Abstract Seventy-seven seedling populations of Douglas-fir (Pseudotsuga menziesii var. glauca) sampled from near the Continental Divide in Idaho and Montana exhibited pronounced genetic differences when compared in three common environments. Differentiation involved several traits that are components of an annual developmental cycle that must be completed within a growing season of finite length. Consequently, the elevational and geographic dines of genetic variation tend to parallel variation in the length of the growing season at the seed source. Such clines suggest that maladaptation in artificial reforestation can be controlled by limiting the transfer of seeds. While geographic transfers can be relatively liberal, elevational transfers should be limited to ±90 m (300 ft) from the seed source at elevations below 1,400 m (4,600 ft), to ±125 m (410 ft) for elevations between 1,400 and 2,000 m (4,600 and 6,550 ft), and ±200 m (560 ft) for elevations above 2,000 m (6,550 ft). West. J. Appl. For. 3(4):101-105, October 1988.
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Fu, Yuqing, Laurent Gavotte, David R. Mercer, and Stephen L. Dobson. "Artificial Triple Wolbachia Infection in Aedes albopictus Yields a New Pattern of Unidirectional Cytoplasmic Incompatibility." Applied and Environmental Microbiology 76, no. 17 (July 2, 2010): 5887–91. http://dx.doi.org/10.1128/aem.00218-10.
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ABSTRACT Obligately intracellular Wolbachia bacteria infect numerous invertebrates and often manipulate host reproduction to facilitate the spread of infection. An example of reproductive manipulation is Wolbachia-induced cytoplasmic incompatibility (CI), which occurs commonly in insects. This CI has been the focus both of basic scientific studies of naturally occurring invasion events and of applied investigations on the use of Wolbachia as a vehicle to drive desired genotypes into insect populations (“gene drive” or “population replacement” strategies). The latter application requires an ability to generate artificial infections that cause a pattern of unidirectional incompatibility with the targeted host population. A suggested target of population replacement strategies is the mosquito Aedes albopictus (Asian tiger mosquito), an important invasive pest and disease vector. Aedes albopictus individuals are naturally “superinfected” with two Wolbachia types: wAlbA and wAlbB. Thus, generating a strain that is unidirectionally incompatible with field populations requires the introduction of an additional infection into the preexisting superinfection. Although prior reports demonstrate an ability to transfer Wolbachia infections to A. albopictus artificially, including both intra- and interspecific Wolbachia transfers, previous efforts have not generated a strain capable of invading natural populations. Here we describe the generation of a stable triple infection by introducing Wolbachia wRi from Drosophila simulans into a naturally superinfected A. albopictus strain. The triple-infected strain displays a pattern of unidirectional incompatibility with the naturally infected strain. This unidirectional CI, combined with a high fidelity of maternal inheritance and low fecundity effects, suggests that the artificial cytotype could serve as an appropriate vehicle for gene drive.
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Bucklin, Katherine A., Michael A. Banks, and Dennis Hedgecock. "Assessing genetic diversity of protected coho salmon (Oncorhynchus kisutch) populations in California." Canadian Journal of Fisheries and Aquatic Sciences 64, no. 1 (January 1, 2007): 30–42. http://dx.doi.org/10.1139/f06-171.
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California coho salmon (Oncorhynchus kisutch) are under legal protection owing to significant declines in abundance over the last decades. Previously, California coho salmon were characterized as having low genetic diversity and weak population subdivision, attributable potentially to homogenization by out-of-basin hatchery releases. Here, diversity at seven highly polymorphic microsatellite DNA markers is assessed within and among 32 collections of coho salmon from 16 California watersheds. In 71% of local populations, genotypic composition deviates significantly from that expected under the assumption of random mating. We develop and apply methods to adjust for two potential causes of deviation from random mating expectations: (i) Wahlund effects, owing to heterogeneous collections of individuals, and (ii) the "Allendorf–Phelp's effect", owing to closely related juveniles in samples. Such population-level "adjustments" reduce within-region and increase among-region variance; after adjustment, we find strong concordance of genetic and geographic distances. We conclude that stock transfers have had minimal impact on population structure and that California coho salmon populations likely comprise small numbers of endemic breeders, potentially experiencing high levels of genetic drift and inbreeding.
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Alter, George C. "Generation to Generation." Social Science History 37, no. 1 (2013): 1–26. http://dx.doi.org/10.1017/s0145553200010555.
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After two centuries of demographic change, societies of European origin face a new reality of aging populations and heightened competition for resources between young and old. Research on the history of the family adds important perspectives on our current problems. In northwestern Europe, transfers of resources to the young and old were constrained by an unusual marriage and household formation system. The transition to small families increased downward intergenerational transfers (parents to children), and compensating upward transfers now take place outside the family. The growing independence of the elderly in the twentieth century is based on earlier investments in children. The members of each generation profit from the investments their parents make in them and the investments they make in the children of others.
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Dixit, Purushottam D., Tin Yau Pang, F. William Studier, and Sergei Maslov. "Recombinant transfer in the basic genome ofEscherichia coli." Proceedings of the National Academy of Sciences 112, no. 29 (July 7, 2015): 9070–75. http://dx.doi.org/10.1073/pnas.1510839112.
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An approximation to the ∼4-Mbp basic genome shared by 32 strains ofEscherichia colirepresenting six evolutionary groups has been derived and analyzed computationally. A multiple alignment of the 32 complete genome sequences was filtered to remove mobile elements and identify the most reliable ∼90% of the aligned length of each of the resulting 496 basic-genome pairs. Patterns of single base-pair mutations (SNPs) in aligned pairs distinguish clonally inherited regions from regions where either genome has acquired DNA fragments from diverged genomes by homologous recombination since their last common ancestor. Such recombinant transfer is pervasive across the basic genome, mostly between genomes in the same evolutionary group, and generates many unique mosaic patterns. The six least-diverged genome pairs have one or two recombinant transfers of length ∼40–115 kbp (and few if any other transfers), each containing one or more gene clusters known to confer strong selective advantage in some environments. Moderately diverged genome pairs (0.4–1% SNPs) show mosaic patterns of interspersed clonal and recombinant regions of varying lengths throughout the basic genome, whereas more highly diverged pairs within an evolutionary group or pairs between evolutionary groups having >1.3% SNPs have few clonal matches longer than a few kilobase pairs. Many recombinant transfers appear to incorporate fragments of the entering DNA produced by restriction systems of the recipient cell. A simple computational model can closely fit the data. Most recombinant transfers seem likely to be due to generalized transduction by coevolving populations of phages, which could efficiently distribute variability throughout bacterial genomes.
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Heinrich, S., M. Henneberg, M. Peglow, J. Drechsler, and L. Mörl. "Fluidized bed spray granulation: analysis of heat and mass transfers and dynamic particle populations." Brazilian Journal of Chemical Engineering 22, no. 2 (June 2005): 181–94. http://dx.doi.org/10.1590/s0104-66322005000200004.
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Cattel, Julien, Katerina Nikolouli, Thibault Andrieux, Julien Martinez, Francis Jiggins, Sylvain Charlat, Fabrice Vavre, David Lejon, Patricia Gibert, and Laurence Mouton. "Back and forth Wolbachia transfers reveal efficient strains to control spotted wing drosophila populations." Journal of Applied Ecology 55, no. 5 (February 9, 2018): 2408–18. http://dx.doi.org/10.1111/1365-2664.13101.
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Myers, Larry L. "Outcomes comparison of head and neck free tissue transfers in three different hospital populations." Microsurgery 29, no. 8 (August 3, 2009): 593–97. http://dx.doi.org/10.1002/micr.20688.
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Yuste, Eloísa, Antonio V. Bordería, Esteban Domingo, and Cecilio López-Galíndez. "Few Mutations in the 5′ Leader Region Mediate Fitness Recovery of Debilitated Human Immunodeficiency Type 1 Viruses." Journal of Virology 79, no. 9 (May 1, 2005): 5421–27. http://dx.doi.org/10.1128/jvi.79.9.5421-5427.2005.
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ABSTRACT Repeated bottleneck passages of RNA viruses result in fitness losses due to the accumulation of deleterious mutations. In contrast, repeated transfers of large virus populations result in exponential fitness increases. Human immunodeficiency virus type 1 (HIV-1) manifested a drastic fitness loss after a limited number of plaque-to-plaque transfers in MT-4 cells. An analysis of the mutations associated with fitness loss in four debilitated clones revealed mutation frequencies in gag that were threefold higher than those in env. We now show an increase in the fitness of the debilitated HIV-1 clones by repeated passages of large populations. An analysis of the entire genomic nucleotide sequences of these populations showed that few mutations, from two to seven per clone, mediated fitness recovery. Eight of the 20 mutations affected coding regions, mainly by the introduction of nonsynonymous mutations (75%). However, most of the mutations accumulated during fitness recovery (12 of 20) were located in the 5′ untranslated leader region of the genome, and more specifically, in the primer binding site (PBS) loop. Two of the viruses incorporated the same mutation in the primer activation signal in the PBS loop, which is critical for the tRNA3 Lys-mediated initiation of reverse transcription. Moreover, 25% of the mutations observed were reversions. This fact, together with the presence of a large proportion of nonsynonymous replacements, may disclose the operation, during large population passages, of strong positive selection for optimal HIV-1 replication, which seems to be primarily affected by binding of the tRNA to the PBS and the initiation of reverse transcription.
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Phelps, S. R., L. L. LeClair, S. Young, and H. L. Blankenship. "Genetic Diversity Patterns of Chum Salmon in the Pacific Northwest." Canadian Journal of Fisheries and Aquatic Sciences 51, S1 (December 19, 1994): 65–83. http://dx.doi.org/10.1139/f94-296.
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We used starch-gel electrophoresis to examine over 13 000 adult chum salmon, Oncorhynchus keta, from 153 collections at 105 locations in Washington, Oregon, and southern British Columbia from 1985–92. We identified 39 variable loci and 36 monomorphic loci. In general, alleles that occurred at a frequency > 10% were found in all locations and were temporally stable within locations. Localized alleles usually occurred at a frequency <6%. Significant allele frequency differences were found among chum salmon populations with different spawning times (summer, fall, and winter), even within the same watershed, and among populations of the same spawning time in different regions. Significant among-population diversity was also found within regions. Multidimensional scaling and UPGMA cluster analysis grouped populations by geography and run-timing, except where past stock transfers have resulted in interbreeding of hatchery and wild fish. These analyses indicate that both geography and spawning time are important isolating mechanisms and that, compared with the other populations, summer-run chum salmon from the Strait of Juan de Fuca and Hood Canal are a distinct evolutionary lineage. This information is currently being used to conserve the genetic diversity of wild chum salmon and manage mixed-stock fisheries.
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Tehrani, Jamshid J., Mark Collard, and Stephen J. Shennan. "The cophylogeny of populations and cultures: reconstructing the evolution of Iranian tribal craft traditions using trees and jungles." Philosophical Transactions of the Royal Society B: Biological Sciences 365, no. 1559 (December 12, 2010): 3865–74. http://dx.doi.org/10.1098/rstb.2010.0020.
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Phylogenetic approaches to culture have shed new light on the role played by population dispersals in the spread and diversification of cultural traditions. However, the fact that cultural inheritance is based on separate mechanisms from genetic inheritance means that socially transmitted traditions have the potential to diverge from population histories. Here, we suggest that associations between these two systems can be reconstructed using techniques developed to study cospeciation between hosts and parasites and related problems in biology. Relationships among the latter are patterned by four main processes: co-divergence, intra-host speciation (duplication), intra-host extinction (sorting) and horizontal transfers. We show that patterns of cultural inheritance are structured by analogous processes, and then demonstrate the applicability of the host–parasite model to culture using empirical data on Iranian tribal populations.
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Henderson, Stacey. "The Arms Trade Treaty: Responsibility to Protect in Action?" Global Responsibility to Protect 9, no. 2 (April 18, 2017): 147–72. http://dx.doi.org/10.1163/1875984x-00902003.
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This paper argues that the influence of R2P can be seen in many subtle, yet significant, ways throughout the Arms Trade Treaty, from the language used to the obligations imposed on States Parties. The Arms Trade Treaty indicates that R2P is influencing decision making and contributing to the protection of populations from atrocity crimes by obliging States Parties to explicitly consider the consequences of their arms transfers. In addition, the Arms Trade Treaty has increased our understanding of R2P by confirming that R2P involves a range of measures and includes restraint by States in refusing to transfer arms in situations where atrocity crimes are being committed, which may temper concerns about R2P being rebranded as assistance.
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Kulakli-Inceleme, Elif, Matthias Knobe, Elmar Fritsche, and Mario F. Scaglioni. "The Role of Free Tissue Transfers for Defect Coverage over the Body in Geriatric Populations." Medicina 57, no. 8 (August 1, 2021): 795. http://dx.doi.org/10.3390/medicina57080795.
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The treatment of soft tissue defects in multimorbid frail patients requires optimized preoperative and perioperative management with a differentiated interdisciplinary approach. Preoperative assessment with established scores, such as the ASA score, is important in order to stratify the operative complication risk. Following the reconstructive ladder is important to avoid unnecessary long operations and consecutively higher operative risks. In cases where a free flap procedure is needed, infections should be treated properly, and vascular status and coagulation should be optimized before performing a free flap procedure. Attention should be paid to maintain independency, functionality and quality of life while choosing the best treatment option.
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Robinson, P. A. "The balanced and introspective brain." Journal of The Royal Society Interface 14, no. 130 (May 2017): 20160994. http://dx.doi.org/10.1098/rsif.2016.0994.
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Transfers of large-scale neural activity into, within and between corticothalamic neural populations and brain hemispheres are analysed using time-integrated transfer functions and state parameters obtained from neural field theory for a variety of arousal states. It is shown that the great majority of activity results from feedbacks within the corticothalamic system, including significant transfer between hemispheres, but only a small minority arises via net input from the external world, with the brain thus in a near-critical, highly introspective state. Notably, the total excitatory and inhibitory influences on cortical neurons are balanced to within a few per cent across arousal states. Strong negative intrahemispheric feedforward exists to the cortex, and even larger interhemispheric positive feedforward, but these are modified by feedback loops to yield near-critical positive overall gain. The results underline the utility of transfer functions for the analysis of brain activity.
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Lopez D., Claudia Marcela, and Isidro Elias Suarez P. "In vitro arrow cane (Gynerium sagitatum Aubl.) multiplication in double phase medium." Revista de Ciencias Agrícolas 35, no. 2 (December 18, 2018): 5–13. http://dx.doi.org/10.22267/rcia.183502.86.
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Arrow cane (Gynerium sagitatum Aubl.) is a Poaceae species used as fiber source to make traditional and valuable handmade craftsmanship by indigenous communities in Northern Colombia. Since no commercial crops are established fiber needs are taken from natural plant populations affecting ecosystem. A micropropagation protocol to clonally multiply large quantities of arrow cane plant material for planting commercial crops has been developed; however, micropropagated plants are costly compared to naturally extracted plant material. To reduce micropropagated plants costs, in the present research a double phase medium formulation along with continuous shoot culture with no periodic transfers to fresh medium was compared to semisolid medium system with subculture every four weeks with respect to multiplication rate and costs of micropropagated plants. The results showed that continuous culture of explants with double phase medium and no periodic transfers resulted in higher multiplication rates and larger shoots compared to shoots cultured using the conventionalsemisolid medium system and transfer to fresh medium every four weeks. Plants from both, semisolid and double phase culture system, fully adapted and recovered when transferred to ex vitro conditions. The cost analysis showed that double phase cultured shoots are ≥20% less expensive.
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Iqbal, Nuzhat, James R. Oliver, Frederic H. Wagner, Audrey J. Lazenby, Charles O. Elson, and Casey T. Weaver. "T Helper 1 and T Helper 2 Cells Are Pathogenic in an Antigen-specific Model of Colitis." Journal of Experimental Medicine 195, no. 1 (January 7, 2002): 71–84. http://dx.doi.org/10.1084/jem.2001889.
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Dysregulated T cell responses to enteric bacteria have been implicated as a common mechanism underlying pathogenesis in rodent models of colitis. However, the bacterial species and T cell specificities that induce disease have been poorly defined. We have developed a model system in which target antigen, bacterial host, and corresponding T cell specificity are defined. OVA-specific T cells from DO11.RAG-2−/− TCR transgenic mice were transferred into RAG-2−/− recipients whose intestinal tracts were colonized with OVA-expressing or control Escherichia coli. Transfer of antigen-naive DO11.RAG-2−/− T cells into recipients colonized with OVA-E. coli resulted in enhanced intestinal recruitment and cell cycling of OVA-specific T cells; however, there was no development of disease. In contrast, transfer of polarized T helper (Th) 1 and Th2 populations resulted in severe wasting and colitis in recipients colonized with OVA-expressing but not control E. coli. The histopathologic features of disease induced by Th1 and Th2 transfers were distinct, but disease severity was comparable. Induction of disease by both Th1 and Th2 transfers was dependent on bacterially associated OVA. These results establish that a single bacterially associated antigen can drive the progression of colitis mediated by both Th1 and Th2 cells and provide a new model for understanding the immunoregulatory interactions between T cells responsive to gut floral antigens.
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Parrish, Colin R., Edward C. Holmes, David M. Morens, Eun-Chung Park, Donald S. Burke, Charles H. Calisher, Catherine A. Laughlin, Linda J. Saif, and Peter Daszak. "Cross-Species Virus Transmission and the Emergence of New Epidemic Diseases." Microbiology and Molecular Biology Reviews 72, no. 3 (September 2008): 457–70. http://dx.doi.org/10.1128/mmbr.00004-08.
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SUMMARY Host range is a viral property reflecting natural hosts that are infected either as part of a principal transmission cycle or, less commonly, as “spillover” infections into alternative hosts. Rarely, viruses gain the ability to spread efficiently within a new host that was not previously exposed or susceptible. These transfers involve either increased exposure or the acquisition of variations that allow them to overcome barriers to infection of the new hosts. In these cases, devastating outbreaks can result. Steps involved in transfers of viruses to new hosts include contact between the virus and the host, infection of an initial individual leading to amplification and an outbreak, and the generation within the original or new host of viral variants that have the ability to spread efficiently between individuals in populations of the new host. Here we review what is known about host switching leading to viral emergence from known examples, considering the evolutionary mechanisms, virus-host interactions, host range barriers to infection, and processes that allow efficient host-to-host transmission in the new host population.
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Marshall, Caroline, and Peter S. Hill. "Ten best resources on conditional cash transfers." Health Policy and Planning 30, no. 6 (June 26, 2014): 742–46. http://dx.doi.org/10.1093/heapol/czu051.
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Abstract The world’s economy is in a fragile state. Although cautiously recovering from a global recession, unemployment rates and poverty levels remain high. At the same time, food and fuel crises have resulted in skyrocketing commodity costs, straining household budgets even further than before. In the wake of these financial pressure points, there has been increased focus on social safety net programmes. More recently, Brazil’s ‘Bolsa Familia’ conditional cash transfer (CCT) programme has celebrated its tenth-year anniversary, renewing focus on this particular aspect of social transfer programmes. This essay examines one particular aspect of these social safety net programmes: CCTs. CCT programmes are useful social programmes that have had demonstrable effects on many different populations. However, they are not a ‘magic bullet’ against poverty, and their image has suffered from unreasonable expectations of their impacts. This 10 best list is an ideal starting point from which a potential user can begin to understand CCTs. There remain significant gaps in the literature behind CCTs, with a particular need for much more research on emerging areas such as impacts on gender, long-term school and health outcomes, methods for increasing efficiency and adapting conditionalities within cultural contexts, among others. However, this list can function as a starting point from which the reader can gain an understanding and appreciation for what we believe to be one of the most innovative social programmes for addressing poverty worldwide.
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Ferguson, Moira M. "The genetic impact of introduced fishes on native species." Canadian Journal of Zoology 68, no. 5 (May 1, 1990): 1053–57. http://dx.doi.org/10.1139/z90-153.
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The introduction of nonnative fishes or "exotics" and transplants of fishes outside their geographic range but within the same country is a contentious issue. The effects of these introductions on native fish faunas are well documented and have resulted in legislation controlling future introductions of alien species and management policies based largely on living with past mistakes. However, fish introductions also occur at two more subtle levels: transfers within the range of the species, and introduction of foreign DNA to produce "transgenics." The rationale for transfers is largely typological in that "a fish is a fish," at least as far as any given species might be concerned. Transfers disregard the concept that species are divided into genetically distinct units or "stocks" adapted to their particular environment and that introduction of nonlocal conspecifics can disrupt the genetics and adaptation of local populations. This paper raises some of the major issues and the need to synthesize the concepts, documented cases, and effects.
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de la Iglesia, Francisca, and Santiago F. Elena. "Fitness Declines in Tobacco Etch Virus upon Serial Bottleneck Transfers." Journal of Virology 81, no. 10 (March 7, 2007): 4941–47. http://dx.doi.org/10.1128/jvi.02528-06.
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ABSTRACT It has been well established that populations of RNA viruses transmitted throughout serial bottlenecks suffer from significant fitness declines as a consequence of the accumulation of deleterious mutations by the onset of Muller's ratchet. Bottlenecks are unavoidably linked to different steps of the infectious cycle of most plant RNA viruses, such as vector-mediated transmissions and systemic colonization of new leaves. Here we report evidence for fitness declines by the accumulation of deleterious mutations in the potyvirus Tobacco etch virus (TEV). TEV was inoculated into the nonsystemic host Chenopodium quinoa, and local lesions were isolated and used to initiate 20 independent mutation accumulation lineages. Weekly, a random lesion from each lineage was isolated and used to inoculate the next set of plants. At each transfer, the Malthusian growth rate was estimated. After 11 consecutive transfers, all lineages suffered significant fitness losses, and one even became extinct. The average rate of fitness decline was 5% per day. The average pattern of fitness decline was consistent with antagonistic epistasis between deleterious mutations, as postulated for antiredundant genomes. Temporal fitness fluctuations were not explained by random noise but reflected more complex underlying processes related to emergence and self-organization phenomena.
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Wosula, E. N., A. J. McMechan, C. Oliveira-Hofman, S. N. Wegulo, and G. L. Hein. "Differential Transmission of Two Isolates of Wheat streak mosaic virus by Five Wheat Curl Mite Populations." Plant Disease 100, no. 1 (January 2016): 154–58. http://dx.doi.org/10.1094/pdis-03-15-0342-re.
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Wheat streak mosaic virus (WSMV), type member of the genus Tritimovirus in the family Potyviridae, is an economically important virus causing annual average yield losses of approximately 2 to 3% in winter wheat across the Great Plains. The wheat curl mite (WCM), Aceria tosichella, transmits WSMV along with two other viruses found throughout the Great Plains of the United States. Two common genotypes of WSMV (Sidney 81 and Type) in the United States share 97.6% nucleotide sequence identity but their transmission relationships with the WCM are unknown. The objective of this study was to determine transmission of these two isolates of WSMV by five WCM populations (‘Nebraska’, ‘Montana’, ‘South Dakota’, ‘Type 1’, and ‘Type 2’). Nonviruliferous mites from each population were reared on wheat source plants mechanically inoculated with either Sidney 81 or Type WSMV isolates. For each source plant, individual mites were transferred to 10 separate test plants and virus transmission was determined by a double-antibody sandwich enzyme-linked immunosorbent assay. Source plants were replicated nine times for each treatment (90 individual mite transfers). Results indicate that three mite populations transmitted Sidney 81 at higher rates compared with Type. Two mite populations (Nebraska and Type 2) transmitted Sidney 81 and Type at higher rates compared with the other three populations. Results from this study demonstrate that interactions between virus isolates and mite populations influence the epidemiology of WSMV.
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Carlson, D. F., J. R. Dobrinsky, and S. C. Fahrenkrug. "327 HIGH EFFICIENCY SWINE CLONING USING MONOGENIC AND POLYGENIC POOLS OF GENETICALLY MODIFIED CELLS." Reproduction, Fertility and Development 23, no. 1 (2011): 260. http://dx.doi.org/10.1071/rdv23n1ab327.
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Somatic cell nuclear transfer (SCNT) of genetically modified (GM) cells is currently the most widely applied method for the creation of transgenic swine. However, significant clone-to-clone variation in the efficiency of SCNT for a variety of genetically modified cell lines is commonly observed and contributes to the expense of transgenic animal production. A retrospective look at our own results based on the use of monoclonal GM cell lines as donors revealed a dismal efficiency of only 13% (15 embryo transfers resulting in only 2 full term pregnancies). Thus, while SCNT of individual GM clones offers the perceived advantage of prior characterisation of transgene expression or structure, the variability of clonability for any given cell line adds risk to SCNT. In contrast, rates of pregnancy when we used pools of GM cells as donors for SCNT were much better (9 full term pregnancies from 11 transfers, ∼82% efficiency). Four of these litters were derived from polyclonal but monogenic GM cell populations constitutively expressing either human APOBEC3G or YFP-Cre transgenes integrated using the Sleeping Beauty transposon system. Four litters relied on a novel approach, wherein different polyclonal and monogenic GM cell populations (containing different transgenes) were mixed before being used as donors for SCNT. For example, 2 litters were derived from the pooling of 2 GM cell populations carrying different tetracycline inducible or repressible shRNA transgenes, resulting in founders harboring each of the shRNA transgenes (4 in total). Two litters were also created from a pool of 3 distinct polyclonal cell populations, each harboring a different Cre-lox regulated transgene, resulting in the birth of 11 live piglets with founders corresponding to each of the transgenes. Thus, both mono- and polygenic pooling of GM cells significantly enhances the success of SCNT, largely avoiding variation in cell clonability. Furthermore, pooling results in a significant reduction in the time and number of surrogates required to generate a diversity of genetically modified pigs. Importantly, the use of Sleeping Beauty transgene integration resulted in a high rate of transgene-expressing founders. Where expected, the gene of interest transgenes were expressed in 23 of 29 founders (79%), whereas selectable marker transgene expression was observed in 35 of 40 founders (88%). The combination of efficient SCNT from polyclonal and polygenic cell populations and the high proportion of expressers delivered by Sleeping Beauty transgene integration offer a high-efficiency, low-risk solution to swine transgenesis.
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Kind-Kovács, Friederike. "Crossing Germany’s Iron Curtain." East Central Europe 41, no. 2-3 (December 3, 2014): 180–203. http://dx.doi.org/10.1163/18763308-04103002.
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In recent years, historians have slowly lost interest in depicting the Cold War as a unique ideological contest between the “real existing” socialist East and the capitalist West. In this spirit, this text examines the social practice of literary transfers, i.e., the exchange of literary works across borders. These transfers sought to physically restore an unraveled Europe that had come about as a result of the ideological and often personal division of Europe’s (and Germany’s) populations. Focusing on the practice of literary transfers across the Iron Curtain permits us to understand borders as symbolic spaces of the Cold War, although they had supposedly been hermetically sealed. Current research on opposition movements in Cold War Europe is still dominated by the widespread notion that oppositional phenomena in thegdrrepresent a research area distinct from other oppositional movements in the Eastern bloc. Possibly due to Germany’s singular dividedness, this perception has often led to individual studies of oppositional phenomena, especially in the literary field, in the formergdr, thereby obscuring parallels in Central and Eastern Europe. As a critical response, this text distances itself from the division of the Soviet bloc’s cultural history into irreconcilable geographical subareas. In doing so, it exemplifies literary transfers both across the German-German border as well as across the East-West Iron Curtain.
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Blockeel, Christophe, Alison Campbell, Giovanni Coticchio, John Esler, Juan A. Garcia-Velasco, Pietro Santulli, and Anja Pinborg. "Should we still perform fresh embryo transfers in ART?" Human Reproduction 34, no. 12 (December 1, 2019): 2319–29. http://dx.doi.org/10.1093/humrep/dez233.
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Abstract An increasing number of researchers have alluded to the potential benefit of deferring the transfer of embryos produced during assisted reproductive technologies (ARTs) away from ovarian stimulation, using cryopreservation to enable this. The scientific evidence that may justify this recent trend in the use of the so-called ‘freeze-all strategy’ includes early, mostly small randomised controlled trials that have demonstrated an increase in live birth rates after elective embryo cryopreservation in certain patient populations, as well as evidence from cohort studies and retrospective analyses. What are the risks and benefits of freeze-all strategies in ART, who are the patients in whom it is likely to be advantageous, and does the current evidence allow us to identify situations when deciding that a fresh embryo transfer would be counter-productive? ART professionals are often faced with challenging clinical decisions regarding the best course of treatment for their patient. The purpose of this opinion paper is to provide a clinical guide for whether to perform a fresh embryo transfer or to opt for freezing all embryos in specific situations.
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Beacham, Terry D., Clyde B. Murray, and L. Walter Barner. "Influence of photoperiod on the timing of reproductive maturation in pink salmon (Oncorhynchus gorbuscha) and its application to genetic transfers between odd- and even-year spawning populations." Canadian Journal of Zoology 72, no. 5 (May 1, 1994): 826–33. http://dx.doi.org/10.1139/z94-112.
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Pink salmon (Oncorhynchus gorbuscha) embryos were obtained in April 1991 from the first generation of a 1989 brood line, which had been induced to spawn 6 months earlier than wild populations, which spawn in October. These embryos and subsequent juveniles were reared at a development temperature and under a photoperiod regime that induced some fish from this second generation to mature in October 1992, the correct time of year for spawning of wild populations. Other captive groups of pink salmon also matured in April 1993, permitting a comparison of fecundity, egg fertility, and egg size among female spawners in different photoperiods. Although the wild population spawns only in odd years, the captive population, originally derived from odd-year spawners, has been manipulated to spawn in even years. This shifting of the spawning time of the captive population may permit a transplant of odd-year genes into an even-year line, perhaps allowing the development of a run of even-year pink salmon in the Fraser River, British Columbia.
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Matoušek, J., L. Orctová, J. Ptáček, J. Patzak, P. Dědič, G. Steger, and D. Riesner. "Experimental Transmission of Pospiviroid Populations to Weed Species Characteristic of Potato and Hop Fields." Journal of Virology 81, no. 21 (August 22, 2007): 11891–99. http://dx.doi.org/10.1128/jvi.01165-07.
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ABSTRACT Weed plants characteristic for potato and hop fields have not been considered in the past as potential hosts that could transmit and lead to spreading of potato spindle tuber (PSTVd) and hop stunt (HSVd) viroids, respectively. To gain insight into this problem, we biolistically inoculated these weed plants with viroid populations either as RNA or as cDNA. New potential viroid host species, collected in central Europe, were discovered. From 12 weed species characteristic for potato fields, high viroid levels, detectable by molecular hybridization, were maintained after both RNA and DNA transfers in Chamomilla reculita and Anthemis arvensis. Low viroid levels, detectable by reverse transcription-PCR (RT-PCR) only, were maintained after plant inoculations with cDNA in Veronica argensis and Amaranthus retroflexus. In these two species PSTVd concentrations were 105 and 103 times, respectively, lower than in tomato as estimated by real-time PCR. From 14 weeds characteristic for hop fields, high HSVd levels were detected in Galinsoga ciliata after both RNA and DNA transfers. HSVd was found, however, not to be transmissible by seeds of this weed species. Traces of HSVd were detectable by RT-PCR in HSVd-cDNA-inoculated Amaranthus retroflexus. Characteristic monomeric (+)-circular and linear viroid RNAs were present in extracts from weed species propagating viroids to high levels, indicating regular replication, processing, and circularization of viroid RNA in these weed species. Sequence analyses of PSTVd progenies propagated in C. reculita and A. arvensis showed a wide spectrum of variants related to various strains, from mild to lethal variants; the sequence variants isolated from A. retroflexus and V. argensis exhibited similarity or identity to the superlethal AS1 viroid variant. All HSVd clones from G. ciliata corresponded to a HSVdg variant, which is strongly pathogenic for European hops.
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Gould, Peter J., Constance A. Harrington, and J. Bradley St. Clair. "Incorporating genetic variation into a model of budburst phenology of coast Douglas-fir (Pseudotsuga menziesii var. menziesii)." Canadian Journal of Forest Research 41, no. 1 (January 2011): 139–50. http://dx.doi.org/10.1139/x10-191.
Full textAbstract:
Models to predict budburst and other phenological events in plants are needed to forecast how climate change may impact ecosystems and for the development of mitigation strategies. Differences among genotypes are important to predicting phenological events in species that show strong clinal variation in adaptive traits. We present a model that incorporates the effects of temperature and differences among genotypes to predict the timing of budburst of coast Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco). The main components of the model are (i) functions to calculate the accumulation of chilling units (CU) and forcing units (FU) during dormancy and (ii) a function defining the combinations of CU and FU needed for budburst (the possibility line). The possibility line was fit to data from 59 populations subjected to eight different winter environments. Differences among populations were incorporated into the possibility line using population coefficients that vary the FU required for budburst. Correlations among the population coefficients and variables describing local environments supported the hypothesis that genetic variation in budburst is largely an adaptation to summer drought. The new model can be used to test potential seed transfers as a strategy to mitigate some of the effects of climate change.