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1.
Under time‐selected migration, birds should choose a strategy for outcompeting rivals over securing access to prime resources at the final destination. Thus, migration can be viewed as a race among individuals where winners are arriving first when conditions are suitable. The sprint migration hypothesis predicts that individuals shift from maximum sustained speed to a final burst of sprint to shorten the transition from migration to breeding (Alerstam, 2006). In this study, we test the hypothesis of a final sprint migration in a long‐distance Afro‐Palearctic migrant, the collared flycatcher Ficedula albicollis, during autumn and spring, and compare migration strategies between the seasons. In both seasons, collared flycatchers evidently exhibited sprint migration by increasing their overall speed over the last leg of migration after the Sahara crossing. This phenomenon was more pronounced in spring, contributing to overall faster spring migration and possibly highlighting higher importance for early arrival at the breeding grounds. In both seasons and particularly in spring, late departing individuals flew at a faster rate, partially being able to catch up with their early departing conspecifics. Differential fueling strategies may play an important role in determining migration speed, especially during the early stages of the migration, and might explain the observed differences in migration speeds between late and early departing individuals. Our findings suggest competition for early arrival at the breeding and at the nonbreeding destinations alike. Sprint migration might be an appropriate strategy to gain advantage over conspecifics and settle in prime territories as well as to cope with the increasingly earlier springs at high latitudes. 相似文献
2.
How individual birds schedule their movements and use different sites during the non‐breeding season are fundamental issues in avian migration ecology, and studies have often revealed strong seasonal variation in such strategies. Using geolocators we tracked Common Ringed Plovers Charadrius hiaticula from northern Norway to West Africa and back to assess whether there were differences in migratory speed, duration and stopover use between autumn and spring migration and whether birds used multiple sites during the non‐breeding season. Although the pace of migration was similar between autumn and spring, the length of flight bouts and duration of the preceding stopovers were positively correlated only in autumn. Four of five birds showed a marked southward movement in mid‐winter. 相似文献
3.
Sear R 《American journal of physical anthropology》2007,132(4):632-641
Life history theory predicts that where resources are limited, investment in reproduction will cause a decline in body condition and ultimately may lower survival rates. We investigate the relationship between reproduction and mortality in women in rural Gambia. We use a number of different measures of reproductive investment: the timing of reproduction, intensity of reproduction, and cumulative reproductive investment (parity). Though giving birth is clearly a risk factor for increased mortality, we find limited evidence that the timing, intensity, or cumulative effects of reproduction have a survival cost. Instead, there is some evidence that women who have invested heavily in reproduction have higher survival than women with lower reproductive investment: both high parity and late age at last reproduction are associated with high survival. The only evidence for any cost of reproduction is that women who have given birth to twins (considered a marker of heavy investment in reproduction) have higher mortality rates than other women, after the age of 50 years. A potential confounding factor may be differences in health between women: particularly healthy women may be able to invest substantially in both reproduction and their own survival, leading to the positive correlations between survival and both parity and age at last birth we observe. To control for differences in health between women, we reanalyze the relationship between reproduction and mortality but include variables correlating with health in our models (height, BMI, and hemoglobin). Even when controlling for health, the positive correlation between investment in reproduction and survival remains unchanged. 相似文献
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5.
Muhammed O. Afolabi Morenike Oluwatoyin Folayan Nchangwi Syntia Munung Aminu Yakubu Gibril Ndow Ayodele Jegede Jennyfer Ambe Francis Kombe 《Developing world bioethics》2021,21(1):25-30
COVID‐19, caused by a novel coronavirus named SARS‐CoV‐2, was identified in December 2019, in Wuhan, China. It was first confirmed in sub‐Saharan Africa in Nigeria on 27 February 2020 and has since spread quickly to all sub‐Saharan African countries, causing more than 111,309 confirmed cases and 2,498 deaths as of 03 June 2020. The lessons learned during the recent Ebola virus disease (EVD) outbreaks in some sub‐Saharan African countries were expected to shape and influence the region’s responses to COVID‐19 pandemic. However, some of the challenges associated with the management of the EVD outbreaks persist and create obstacles for the effective management of the COVID‐19 pandemic. This article describes the commonalities between the EVD epidemics and COVID‐19 pandemic, with a view to draw on lessons learned to effectively tackle the ongoing pandemic. Key successes, failures and lessons learned from previous EVD outbreaks are discussed. Recommendations on how these lessons can be translated to strengthen the COVID‐19 response in sub‐Saharan Africa are provided. 相似文献
6.
Kimberly Jarvis 《Developing world bioethics》2017,17(1):50-58
When conducting research in an international setting, in a country different than that of the researcher, unpredictable circumstances can arise. A study conducted by a novice North American researcher with a vulnerable population in northern Ghana highlights these happenings with an emphasis placed on the ethical challenges encountered. An illustration from the research is used to highlight an ethical dilemma while in the field, and how utilizing a moral decision‐making framework can assist in making choices about a participant's right to autonomy, privacy, and confidentiality during the research process. Moral frameworks, however, can never be enough to solve a dilemma since guidelines only describe what to aim for and not how to interpret or use them. Researchers must therefore strive to move beyond these frameworks to employ practical wisdom or phronesis so to combine the right thing to do with the skill required to figure out what the right choice is. The skill of practical wisdom must be acquired because without it international researchers indecisively fumble around with good intentions, often leaving a situation in worse shape than they found it. 相似文献
7.
Loredana Castrì Sergio Tofanelli Paolo Garagnani Carla Bini Xenia Fosella Susi Pelotti Giorgio Paoli Davide Pettener Donata Luiselli 《American journal of physical anthropology》2009,140(2):302-311
In this study, we report novel data on mitochondrial DNA in two of the largest eastern Bantu‐speaking populations, the Shona from Zimbabwe and the Hutu from Rwanda. The goal is to evaluate the genetic relationships of these two ethnic groups with other Bantu‐speaking populations. Moreover, by comparing our data with those from other Niger‐Congo speaking populations, we aim to clarify some aspects of evolutionary and demographic processes accompanying the spread of Bantu languages in sub‐Saharan Africa and to test if patterns of genetic variation fit with models of population expansion based on linguistic and archeological data. The results indicate that the Shona and Hutu are closely related to the other Bantu‐speaking populations. However, there are some differences in haplogroup composition between the two populations, mainly due to different genetic contributions from neighboring populations. This result is confirmed by estimates of migration rates which show high levels of gene flow not only between pairs of Bantu‐speaking populations, but also between Bantu and non‐Bantu speakers. The observed pattern of genetic variability (high genetic homogeneity and high levels of gene flow) supports a linguistic model suggesting a gradual spread of Bantu‐speakers, with strong interactions between the different lines of Bantu‐speaker descent, and is also in agreement with recent archeological findings. In conclusion, our data emphasize the role that population admixture has played at different times and to varying degrees in the dispersal of Bantu languages. Am J Phys Anthropol, 2009. © 2009 Wiley‐Liss, Inc. 相似文献
8.
Morenike O. Folayan Kolawole S. Oyedeji Olawunmi A. Fatusi 《Developing world bioethics》2015,15(1):1-7
In this paper, we describe the potential role laypersons on ethics committees can play in ensuring community concerns are addressed in the design and implementation of genomic research. We draw inferences from the outcome of an empirical study of the impact of training of laypersons to address community engagement issues in ethics review of research protocol. While this paper does not advocate a particular solution, it describes the importance of community engagement in genomic research, the current limitations there are in engaging communities in the design of these research projects and how communities can be indirectly engaged in the design and implementation of genomic research through the engagement of laypersons on ethics committees. However, to ensure that these laypersons can play this role, their capacity needs to be built to play this role appropriately. There is evidence to show that where resources are invested in building the capacity of laypersons to play their role as community ‘watchdogs’ in research, they play this role aptly. Community engagement is important in genomic research as genomic researchers will increasingly require community perspectives in critical ethics decision making. 相似文献
9.
Morenike Oluwatoyin Folayan Aisha Adaranijo Florita Durueke Ademola Ajuwon Adebayo Adejumo Oliver Ezechi Kola Oyedeji Olayide Akanni 《Developing world bioethics》2014,14(1):1-14
This paper describes a three‐year project designed to build the capacity of members of research ethics committes to perform their roles and responsibilities efficiently and effectively. The project participants were made up of a cross‐section of the membership of 13 Research Ethics Committees (RECs) functioning in Nigeria. They received training to develop their capacity to evaluate research protocols, monitor trial implementation, provide constructive input to trial staff, and assess the trial's success in promoting community engagement in the research. Following the training, technical assistance was provided to participants on an ongoing basis and the project's impacts were assessed quantitatively and qualitatively. Results indicate that sustained investment in capacity building efforts (including training, ongoing technical assistance, and the provision of multiple tools) improved the participants’ knowledge of both the ethical principles relevant to biomedical research and how effective REC should function. Such investment was also shown to have a positive impact on the knowledge levels of other RECs members (those who did not receive training) and the overall operations of the RECs to which the participants belonged. Building the capacity of REC members to fulfill their roles effectively requires sustained effort and investment and pays off by enabling RECs to fulfill their essential mission of ensuring that trials are conducted safely and ethically. 相似文献
10.
Katharina Stein Kathrin Stenchly Drissa Coulibaly Alain Pauly Kangbeni Dimobe Ingolf Steffan‐Dewenter Souleymane Konaté Dethardt Goetze Stefan Porembski K. Eduard Linsenmair 《Ecology and evolution》2018,8(13):6827-6838
All over the world, pollinators are threatened by land‐use change involving degradation of seminatural habitats or conversion into agricultural land. Such disturbance often leads to lowered pollinator abundance and/or diversity, which might reduce crop yield in adjacent agricultural areas. For West Africa, changes in bee communities across disturbance gradients from savanna to agricultural land are mainly unknown. In this study, we monitored for the impact of human disturbance on bee communities in savanna and crop fields. We chose three savanna areas of varying disturbance intensity (low, medium, and high) in the South Sudanian zone of Burkina Faso, based on land‐use/land cover data via Landsat images, and selected nearby cotton and sesame fields. During 21 months covering two rainy and two dry seasons in 2014 and 2015, we captured bees using pan traps. Spatial and temporal patterns of bee species abundance, richness, evenness and community structure were assessed. In total, 35,469 bee specimens were caught on 12 savanna sites and 22 fields, comprising 97 species of 32 genera. Bee abundance was highest at intermediate disturbance in the rainy season. Species richness and evenness did not differ significantly. Bee communities at medium and highly disturbed savanna sites comprised only subsets of those at low disturbed sites. An across‐habitat spillover of bees (mostly abundant social bee species) from savanna into crop fields was observed during the rainy season when crops are mass‐flowering, whereas most savanna plants are not in bloom. Despite disturbance intensification, our findings suggest that wild bee communities can persist in anthropogenic landscapes and that some species even benefitted disproportionally. West African areas of crop production such as for cotton and sesame may serve as important food resources for bee species in times when resources in the savanna are scarce and receive at the same time considerable pollination service. 相似文献
11.
The Johns Hopkins-Fogarty African Bioethics Training Program (FABTP) has offered a fully-funded, one-year, non-degree training opportunity in research ethics to health professionals, ethics committee members, scholars, journalists and scientists from countries across sub-Saharan Africa. In the first 9 years of operation, 28 trainees from 13 African countries have trained with FABTP. Any capacity building investment requires periodic critical evaluation of the impact that training dollars produce. In this paper we describe and evaluate FABTP and the efforts of its trainees. Our data show that since 2001, the 28 former FABTP trainees have authored or co-authored 105 new bioethics-related publications; were awarded 33 bioethics-related grants; played key roles on 78 bioethics-related research studies; and participated in 198 bioethics workshops or conferences. Over the past nine years, trainees have collectively taught 48 separate courses related to bioethics and have given 170 presentations on various topics in the field. Many former trainees have pursued and completed doctoral degrees in bioethics; some have become editorial board members for bioethics journals. Female trainees were, on average, less experienced at matriculation and produced fewer post-training outputs than their male counterparts. More comprehensive studies are needed to determine the relationships between age, sex, previous experience and training program outputs. 相似文献
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Christoph Müller Katharina Waha Alberte Bondeau Jens Heinke 《Global Change Biology》2014,20(8):2505-2517
Development efforts for poverty reduction and food security in sub‐Saharan Africa will have to consider future climate change impacts. Large uncertainties in climate change impact assessments do not necessarily complicate, but can inform development strategies. The design of development strategies will need to consider the likelihood, strength, and interaction of climate change impacts across biosphere properties. We here explore the spread of climate change impact projections and develop a composite impact measure to identify hotspots of climate change impacts, addressing likelihood and strength of impacts. Overlapping impacts in different biosphere properties (e.g. flooding, yields) will not only claim additional capacity to respond, but will also narrow the options to respond and develop. Regions with severest projected climate change impacts often coincide with regions of high population density and poverty rates. Science and policy need to propose ways of preparing these areas for development under climate change impacts. 相似文献
14.
Sonia Altizer Andrew K. Davis 《Evolution; international journal of organic evolution》2010,64(4):1018-1028
The demands of long‐distance flight represent an important evolutionary force operating on the traits of migratory species. Monarchs are widespread butterflies known for their annual migrations in North America. We examined divergence in wing morphology among migratory monarchs from eastern and western N. America, and nonmigratory monarchs in S. Florida, Puerto Rico, Costa Rica, and Hawaii. For the three N. American populations, we also examined monarchs reared in four common environment experiments. We used image analysis to measure multiple traits including forewing area and aspect ratio; for laboratory‐reared monarchs we also quantified body area and wing loading. Results showed wild monarchs from all nonmigratory populations were smaller than those from migratory populations. Wild and captive‐reared eastern monarchs had the largest and most elongated forewings, whereas monarchs from Puerto Rico and Costa Rica had the smallest and roundest forewings. Eastern monarchs also had the largest bodies and high measures of wing loading, whereas western and S. Florida monarchs had less elongated forewings and smaller bodies. Among captive‐reared butterflies, family‐level effects provided evidence that genetic factors contributed to variation in wing traits. Collectively, these results support evolutionary responses to long‐distance flight in monarchs, with implications for the conservation of phenotypically distinct wild populations. 相似文献
15.
John B. A. Okello Christian Noirard Pierre Joly Silvester Nyakaana Vincent B. Muwanika Nicolas Alcala Séverine Vuilleumier Hans R. Siegismund Luca Fumagalli 《Molecular ecology》2015,24(10):2507-2520
Over the past two decades, an increasing amount of phylogeographic work has substantially improved our understanding of African biogeography, in particular the role played by Pleistocene pluvial–drought cycles on terrestrial vertebrates. However, still little is known on the evolutionary history of semi‐aquatic animals, which faced tremendous challenges imposed by unpredictable availability of water resources. In this study, we investigate the Late Pleistocene history of the common hippopotamus (Hippopotamus amphibius), using mitochondrial and nuclear DNA sequence variation and range‐wide sampling. We documented a global demographic and spatial expansion approximately 0.1–0.3 Myr ago, most likely associated with an episode of massive drainage overflow. These events presumably enabled a historical continent‐wide gene flow among hippopotamus populations, and hence, no clear continental‐scale genetic structuring remains. Nevertheless, present‐day hippopotamus populations are genetically disconnected, probably as a result of the mid‐Holocene aridification and contemporary anthropogenic pressures. This unique pattern contrasts with the biogeographic paradigms established for savannah‐adapted ungulate mammals and should be further investigated in other water‐associated taxa. Our study has important consequences for the conservation of the hippo, an emblematic but threatened species that requires specific protection to curtail its long‐term decline. 相似文献
16.
Marion Kalabuanga Raffaella Ravinetto Vivi Maketa Hypolite Muhindo Mavoko Blaise Fungula Raquel Inocêncio da Luz Jean‐Pierre Van Geertruyden Pascal Lutumba 《Developing world bioethics》2016,16(2):64-69
In medical research, the ethical principle of respect for persons is operationalized into the process of informed consent. The consent tools should be contextualized and adapted to the different socio‐cultural environment, especially when research crosses the traditional boundaries and reaches poor communities. We look at the challenges experienced in the malaria Quinact trial, conducted in the Democratic Republic of Congo, and describe some lessons learned, related to the definition of acceptable representative, the role of independent witness and the impact of socio‐economic vulnerability. To ensure children's protection, consent is required by the parents or, in their absence, by a legally mandated representative. In our setting, children's responsibility is often entrusted permanently or temporarily to relatives or friends without a tribunal mandate. Hence, a notion of ‘culturally acceptable representative’ under supervision of the local Ethics Committee may be more suitable. To ensure protection of illiterate subjects, an independent witness is required to confirm that the consent was freely given. However, in low‐literacy contexts, potential witnesses often don't have any previous relationship with patient and there may be power‐unbalance in their relationship, rather than genuine dialogue. In poor communities, trial participation may be seen as an opportunity to secure access to healthcare. Poverty may also lead to ‘competition’ to access the research‐related benefits, with a risk of disturbance at societal or household level. Adjusting consent procedures to sociocultural and socioeconomic realities is essential for fulfilling the underlying ethical principles. This requires a collaborative dialogue between researchers, regulators and ethics committees. 相似文献
17.
Catriona A. Morrison Robert A. Robinson Jacquie A. Clark Kate Risely Jennifer A. Gill 《Diversity & distributions》2013,19(8):1051-1058
Aim
Recent, rapid population declines in many Afro‐Palaearctic migratory bird species have focussed attention on changing conditions within Africa. However, processes influencing population change can operate throughout the annual cycle and throughout migratory ranges. Here, we explore the evidence for impacts of breeding and non‐breeding conditions on population trends of British breeding birds of varying migratory status and wintering ecology.Location
Great Britain (England & Scotland).Methods
Within‐ and between‐species variation in population trends is quantified for 46 bird species with differing migration strategies.Results
Between 1994 and 2007, rates of population change in Scotland and England differed significantly for 19 resident and 15 long‐distance migrant species, but were similar for 12 short‐distance migrant species. Of the six long‐distance migrant species that winter in the arid zone of Africa, five are increasing in abundance throughout Britain. In contrast, the seven species wintering in the humid zone of Africa are all declining in England, but five of these are increasing in Scotland. Consequently, populations of both arid and humid zone species are increasing significantly faster in Scotland than England, and only the English breeding populations of species wintering in the humid zone are declining.Main conclusions
Population declines in long‐distance migrants, especially those wintering in the humid zone, but not residents or short‐distance migrants suggest an influence of non‐breeding season conditions on population trends. However, the consistently less favourable population trends in England than Scotland of long‐distance migrant and resident species strongly suggest that variation in the quality of breeding grounds is influencing recent population changes. The declines in humid zone species in England, but not Scotland, may result from poorer breeding conditions in England exacerbating the impacts of non‐breeding conditions or the costs associated with a longer migration, while better conditions in Scotland may be buffering these impacts.18.
Catriona A. Morrison Robert A. Robinson Jacquie A. Clark Jennifer A. Gill 《Diversity & distributions》2010,16(4):620-627
Aim Over the past three decades, evidence has been growing that many Afro‐Palaearctic migratory bird populations have suffered sustained and severe declines. As causes of these declines exist across both the breeding and non‐breeding season, identifying potential drivers of population change is complex. In order to explore the roles of changes in regional and local environmental conditions on population change, we examine spatial and temporal variation in population trajectories of one of Europe’s most abundant Afro‐Palaearctic summer migrants, the willow warbler, Phylloscopus trochilus. Location Britain and Ireland. Methods We use national survey data from Britain and Ireland (BBS: BTO/RSPB/JNCC Breeding Bird Survey and CBS: BWI/NPWS/Heritage Council Countryside Breeding Survey) from 1994 to 2006 to model the spatial and temporal variation in willow warbler population trends. Results Across Britain and Ireland, population trends follow a gradient from sharp declines in the south and east of England to shallow declines and/or slight increases in parts of north and west England, across Scotland and Ireland. Decreasing the spatial scale of analysis reveals variation in both the rate and spatial extent of population change within central England and the majority of Scotland. The rates of population change also vary temporally; declines in the south of England are shallower now than at the start of the time series, whereas populations further north in Britain have undergone periods of increase and decline. Main conclusion These patterns suggest that regional‐scale drivers, such as changing climatic conditions, and local‐scale processes, such as habitat change, are interacting to produce spatially variable population trends. We discuss the potential mechanisms underlying these interactions and the challenges in addressing such changes at scales relevant to migratory species. 相似文献
19.
Morenike Oluwatoyin Folayan Brandon Brown Bridget Haire Chinedum Peace Babalola Nicaise Ndembi 《Developing world bioethics》2021,21(1):44-50
The aim of this study is to determine how stakeholder engagement can be adapted for the conduct of COVID‐19‐related clinical trials in sub‐Saharan Africa. Nine essential stakeholder engagement practices were reviewed: formative research; stakeholder engagement plan; communications and issues management plan; protocol development; informed consent process; standard of prevention for vaccine research and standard of care for treatment research; policies on trial‐related physical, psychological, financial, and/or social harms; trial accrual, follow‐up, exit trial closure and results dissemination; and post‐trial access to trial products or procedures. The norms, values, and practices of collectivist societies in Sub‐Saharan Africa and the low research literacy pose challenges to the conduct of clinical trials. Civil‐society organizations, members of community advisory boards and ethics committees, young persons, COVID‐19 survivors, researchers, government, and the private sector are assets for the implementation and translation of COVID‐19 related clinical trials. Adapting ethics guidelines to the socio‐cultural context of the region can facilitate achieving the aim of stakeholder engagement. 相似文献
20.
Biogas could provide a more sustainable energy source than wood fuels for rural households in sub‐Saharan African. However, functioning of biogas digesters can be limited in areas of low water availability. The water required is approximately 50 dm3 day?1 for each cow and 10 dm3 day?1 for each pig providing manure to the digester, or 25 (±6) dm3 day?1 for each person in the household, using a digester volume of 1.3 (±0.3) m3 capita?1. Here, we consider the potential of domestic water recycling, rainwater harvesting, and aquaculture to supply the water needed for digestion in different countries of sub‐Saharan Africa. Domestic water recycling was found to be important in every country but was usually insufficient to meet the requirements of the digester, with households in 72% of countries need to collect additional water. Rooftop rainwater harvesting also has an important role, iron roofs being more effective than thatched roofs at collecting water. However, even with an iron roof, the size of roof commonly found in sub‐Saharan Africa (15 to 40 m2) is too small to collect sufficient water, requiring an extra area (in m2) for each person of (R/100) (where R is the rainfall in mm). If there is a local market for fish, stocking a pond with tilapia, fed on plankton growing on bioslurry from the digester, could provide an important source of additional income and hold the water required by the digester. In areas where rainfall is low and seasonal, the fishpond might be stocked only in the rainy season, allowing the pond to be covered during the dry period to reduce evaporation. If evaporative losses (E in mm) exceed rainfall, an extra catchment area is needed to maintain the water level in the pond, equivalent to approximately (1.5 × ((E?R)/R)) m2 for each person in the household. 相似文献