Maintenance of sympatric floral tube‐length variation in a Cape irid

Transition zones between morphologically different individuals of the same species provide insights into the evolution and maintenance of gene‐flow barriers. Here we investigate Tritoniopsis revoluta, which has geographically variable tube lengths, thought to be adaptations to insects with different proboscis lengths. We found a narrow transition zone between plants differing by three‐fold in perianth tube length. We determined whether strong gene‐flow barriers result from assortative mating arising from different pollinators, a high prevalence of selfing, or post‐pollination incompatibilities between plants with different tube lengths. We found that there was little evidence to support assortative mating through different pollinators. Both short‐ and long‐tubed plants were mainly visited by bees with short proboscides. Selfing is unlikely to contribute significantly to seed set, plants with different tube lengths were interfertile and hybrid plants were fertile. We conclude that the contact zone is unstable because these ecotypes have not accrued enough allopatric differences to translate into strong gene‐flow barriers, or, alternatively, bimodality is not a consequence of secondary contact but the result of a novel mutation for short tubes spreading through a long‐tubed population. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 104 , 129–137.     

Mechanisms of reproductive isolation of interspecific hybridization between Trillium camschatcense and T. tschonoskii (Melanthiaceae)

Reproductive isolation plays a significant role in the prevention of gene flow between different plant species. Isolation factors can vary, acting either pre‐ or postzygotically. Trillium camschatcense and T. tschonoskii are herbaceous perennials which frequently grow together in Hokkaido, Japan. Natural hybrid formation, T. × hagae, between these species is common, and occurs asymmetrically with T. camschatcense as the maternal parent and T. tschonoskii as the paternal. Here, we examined the efficiency of each reproductive isolation factor to clarify which factor was responsible for the frequency and asymmetry of the hybridization. We found that prezygotic barriers, self fertilization and conspecific pollen precedence, are major isolation factors in both parental species, and that T. tschonoskii as a maternal parent has more effective prezygotic barriers than T. camschatcense. In addition, hybrids with T. tschonoskii as the maternal parent were not observed to reach the flowering stage. We concluded that prezygotic isolation factors in the both species act as main barriers to prevent natural hybridization, and that asymmetry of the isolating barriers between these species would promote T. camschatcense as the maternal parent of the hybrids.     

多维度视角下关于基层版基本药物流通障碍的循证研究

目的 从多维度分析基层版基本药物流通的障碍，在此基础上得出相关结论和建议。方法 定量描述，定性分析。结果及结论 通过定量研究发现，基层医务人员对基本药物的认知度较低；患者对基本药物的可获得性低；现有基本药物品种满足患者基本用药需求受到质疑；政府财政投入力度不一，补贴机制不到位；政府机构对基本药物的定位需明确。解决上述问题是保障基本药物基层版顺利流通，提高患者对基本药物可获得性，保证卫生公平，降低群众基本用药费用的关键。     

Influence of Roads,Rivers, and Mountains on Natal Dispersal of White-Tailed Deer

Abstract: Natural and anthropogenic landscape features, such as rivers, mountain ranges, and roads can alter animal dispersal paths and movement patterns. Consequently landscape, through its effects on dispersal, may influence many ecological processes, including disease transmission, invasion dynamics, and gene flow. To investigate influences of landscape features on dispersal patterns of a large mammal, we captured and radiomarked 363 juvenile male white-tailed deer (Odocoileus virginianus), including 212 confirmed dispersers, in 2 topographically dissimilar study areas in Pennsylvania, USA. Dispersal azimuths were uniformly distributed in the western study area (WSA), where there was irregular, hilly topography. Mean dispersal azimuths paralleled ridge direction in the eastern study area, where long parallel ridges were aligned northeast-southwest. Major roads in both areas and a large river in the WSA were semipermeable barriers to dispersal of juvenile males; dispersal paths were less likely to intersect these linear features. Dispersal movements were direct and brief, typically lasting <12 hours. For all dispersers, we found no evidence for preference or avoidance of establishing adult, postdispersal ranges in proximity to roads; however, deer that encountered roads near the terminus of their dispersal path were more likely to stop on the near side. Further, for deer that established postdispersal home ranges near major roads, these features influenced range placement such that locations were typically clustered on one side of the road. The influence of roads, rivers, and mountains on dispersal paths and postdispersal locations of white-tailed deer suggest that landscape-specific features should be considered in conservation and management of this and possibly other species of large mammals.     

Does a predatory insect contribute to the divergence between cave- and surface-adapted fish populations?

Immigrant inviability, where individuals from foreign, ecologically divergent habitats are less likely to survive, can restrict gene flow among diverging populations and result in speciation. I investigated whether a predatory aquatic insect (Belostoma sp.) selects against migrants between cave and surface populations of a fish (Poecilia mexicana). Cavefish were more susceptible to attacks in the light, whereas surface fish were more susceptible in darkness. Environmentally dependent susceptibility to attacks may thus contribute to genetic and phenotypic differentiation between the populations. This study highlights how predation—in this case in conjunction with differences in other environmental factors—can be an important driver in speciation.     

Physician-Reported Barriers to Osteoporosis Screening: A Nationwide Survey

ObjectiveDespite increased awareness, osteoporosis screening rates remain low. The objective of this survey study was to identify physician-reported barriers to osteoporosis screening.MethodsWe conducted a survey of 600 physician members of the Endocrine Society, American Academy of Family Practice, and American Geriatrics Society. The respondents were asked to rate barriers to osteoporosis screening in their patients. We performed multivariable logistic regression analyses to determine correlates with the most commonly reported barriers.ResultsOf 566 response-eligible physicians, 359 completed the survey (response rate, 63%). The most commonly reported barriers to osteoporosis screening included patient nonadherence (63%), physician concern about cost (56%), clinic visit time constraints (51%), low on the priority list (45%), and patient concern about cost (43%). Patient nonadherence as a barrier was correlated with physicians in academic tertiary centers (odds ratio [OR], 2.34; 95% confidence interval [CI], 1.06-5.13), whereas clinic visit time constraints were correlated with physicians in both community-based academic affiliates and academic tertiary care ([OR, 1.96; 95% CI, 1.10-3.50] and [OR, 2.48; 95% CI, 1.22-5.07], respectively). Geriatricians (OR, 0.40; 95% CI, 0.21-0.76) and physicians with >10 years in practice were less likely to report clinic visit time constraints as a barrier (11-20 years: OR, 0.41; 95% CI, 0.20-0.85; >20 years: OR, 0.32; 95% CI, 0.16-0.65). Physicians with more patient-facing time (3-5 compared with 0.5-2 d/wk) were more likely to place screening low on the priority list (OR, 2.66; 95% CI, 1.34-5.29).ConclusionUnderstanding barriers to osteoporosis screening is vital in developing strategies to improve osteoporosis care.     

The Society of Nematologists at 50, and Where to from Here?

Nathan Cobb, as the father figure of the Society of Nematologists, set an example to later generations of nematologists in his studies of nematode biology. In the 50 years of the Society’s existence nematological research has greatly expanded that knowledge base. Opportunities over the next 50 years are boundless in view of advancing technologies and emerging challenges, and this leads to speculation as to what future nematological research advances will enhance peoples’ quality of life.     

Stimulating Natural Regeneration of Tropical Forest on Degraded Land: Approaches,Outcomes, and Information Gaps

Extensive land clearing in many parts of the global tropics is a major threat to biodiversity, and strategies are urgently needed to reinstate forest. Tree planting is a commonly used strategy to rapidly restore forest to degraded landscapes. However, tree planting is expensive, and in most cases financial constraints prevent its use at a scale needed to address the ongoing legacy of land clearing. Here, we conduct a quantitative review of literature from the global tropics and evaluate outcomes of less intensive interventions (i.e. non‐planting) aimed at stimulating natural regeneration of forest. We focus specifically on overcoming barriers to native plant regeneration that predominate in the earliest stages of succession. Common interventions include varied strategies to suppress herbaceous vegetation (e.g. cutting or herbicide treatment), and measures to bolster propagule supply (e.g. direct seeding and artificial bird perches). There was an apparent trend among pair‐wise comparisons of effect sizes to suggest that combined interventions to simultaneously suppress herbaceous vegetation and increase propagule supply resulted in the most consistent outcomes in terms of promoting progress toward restoring forest structure. Despite an obvious demand for lower cost interventions, a paucity of information means that it is still premature to generalize outcomes of specific interventions and their overall cost relative to active tree planting. Nevertheless, we report an increase in research effort in this area, and suggest promising directions to accelerate progress that will improve capacity to select optimal, cost effective strategies that achieve long‐term restoration objectives with a particular level of certainty .