Applications of stable isotope analyses to avian ecology

In the past 20 years the use of stable isotope analysis has become increasingly common in ecological studies. In fact, in some instances these techniques have yielded remarkable insights into the foraging preferences and migrations of birds. Despite these advances and the potential of the approach, it is possibly still not as widely used as might be expected. In this paper we aim to illustrate the potential of the approach in the hope of encouraging more avian ecologists to think again about how these techniques might provide insights in the systems on which they work. We discuss some of the principles behind the approach, and review some of the more recent ornithological studies that have used stable isotope techniques to trace trophic pathways or infer migratory origins. We follow this by discussing some of the latest ideas on how stable isotopes may be used to generate community metrics and close by detailing the important assumptions and caveats that should be considered before undertaking any studies using this technique.     

An alternative theoretical formula for hemoglobin oxygenation

Classical models of homotropic allostery are based on the postulate that the binding sites are equivalent in their ability to interconvert between high and low affinity states, but compelling evidence exists that the subunits of human hemoglobin are not simultaneously available for oxygen equilibration, thus reducing the number of possible intermediate microstates. The incorporation of these results into the Adair scheme reveals an alternative mechanism for hemoglobin oxygenation, not based on affinity changes.     

Estimating evolutionary parameters when viability selection is operating

Some individuals die before a trait is measured or expressed (the invisible fraction), and some relevant traits are not measured in any individual (missing traits). This paper discusses how these concepts can be cast in terms of missing data problems from statistics. Using missing data theory, I show formally the conditions under which a valid evolutionary inference is possible when the invisible fraction and/or missing traits are ignored. These conditions are restrictive and unlikely to be met in even the most comprehensive long-term studies. When these conditions are not met, many selection and quantitative genetic parameters cannot be estimated accurately unless the missing data process is explicitly modelled. Surprisingly, this does not seem to have been attempted in evolutionary biology. In the case of the invisible fraction, viability selection and the missing data process are often intimately linked. In such cases, models used in survival analysis can be extended to provide a flexible and justified model of the missing data mechanism. Although missing traits pose a more difficult problem, important biological parameters can still be estimated without bias when appropriate techniques are used. This is in contrast to current methods which have large biases and poor precision. Generally, the quantitative genetic approach is shown to be superior to phenotypic studies of selection when invisible fractions or missing traits exist because part of the missing information can be recovered from relatives.     

Sex ratio variation in the cooperatively breeding alpine marmot Marmota marmota

In cooperatively breeding vertebrate species, a clear theoreticalprediction about the direction of sex ratio adjustment can bemade: mothers should bias the sex ratio of their offspring towardsthe helping sex when helpers are absent. A consistent trendin the direction predicted by theory exists in cooperative birds,but theory is still poorly tested in cooperative mammals. Here,multivariate analyses are applied to a long-term data set totest this prediction in two ways in the alpine marmot: (1) acrossfemales in a population and (2) in individual females acrossmultiple years. It was shown that in the alpine marmot offspringsex ratio was biased towards the helping sex (males) when helperswere absent, whereas helped mothers produced unbiased sex ratio.Unhelped mothers did not adjust the litter size but producedmore sons and fewer daughters than helped mothers. These resultssupport the theoretical prediction and explain well the malebias observed among juvenile alpine marmots at the populationlevel. The occurrence of possible sex ratio manipulations incooperatively breeding vertebrates is also discussed.     

Variation in reproductive success and effective number of breeders in a hatchery population of steelhead trout (Oncorhynchus mykiss): examination by microsatellite-based parentage analysis

Conservation programs that release captive-bred individuals into the wild to mix with naturally produced individuals are an increasingly common method of supporting or enhancing weak or reduced populations that otherwise may not be self-sustaining. Captive and supportive breeding can be important conservation tools for species with small or declining populations; however, in the case of hatcheries producing salmonid fishes, detailed evaluation of spawning programs is rare. We examined variation in reproductive success, measured by adult offspring production, from three parental generations of hatchery-bred steelhead trout (Oncorhynchus mykiss) using an exclusion-based method of genetic parentage assignment. Reproductive success varied greatly among individuals (especially males) and was correlated with fecundity and maternal spawning date. Estimates of egg to smolt survival for the population as a whole among years ranged from 64% to 95%, marine survival ranged from 0.32% to 2.30%, and the number of adults produced per female ranged from 0 to 18 and the number of adults produced per male ranged from 0 to 32. The effective number of breeders ranged from 11% to 31% of the census population size for that brood year. These ratios fell within estimates from estimates of Ne/N in chinook (O. tshawytscha) and rainbow trout (O. mykiss) hatchery populations.     

新型农村合作医疗单病种支付的管理方式探析

单病种支付作为一种合理控制医疗服务费用的方式,对医疗机构的行为有重要影响。调查发现新农合的单病种的支付方案多采取最高限价和定额补偿相结合的方式;支付标准的设计不尽合理;对医疗质量和过程缺乏监督;遵循临床路径率不高。建议：合理确定单病种支付标准,建立多方位的监督和考核机制,构建新农合单病种支付的管理模式,加强信息化建设。提高医疗机构与医务人员的积极性,实现控制费用、改善质量和提高管理效率的政策目标。     

Lineage interests and nonreproductive strategies

The nonreproductive role of religious women in the European Middle Ages presents the ideal forum for the discussion of elite family strategies within a historical context. I apply the evolutionary concept of kin selection to this group of women in order to explain how a social formation in which religious women failed to reproduce benefited medieval noble lineages. After a brief review of the roles of noble women in the later Middle Ages, I identify two benefits that nonreproductive women provided within a patrilineal inheritance system. First, spatial segregation and Christian ideology together served to curtail the production of offspring who could pose a threat to lineage interests. Second, cloistered noble women served as a strong political and economic bloc that could further lineage interests within a religious context. Finally, I discuss the evolutionary basis for the formation of groups of nonreproductive women. Using the foundation provided by animal behavioral studies, I apply the twin concepts of cooperative breeding and parental manipulation to noble lineages of the medieval period. The comments of Jim Boone, Jeffrey Dickemann, Bob Leonard, Lance Lundquist, Randy Thornhill, and one anonymous reviewer have greatly contributed to the improvement of this paper. Erica Hill is a Ph.D. candidate in anthropology at the University of New Mexico. She is an archaeologist with multidisciplinary interests in the study of ethnohistory, gender, and anthropological theory.     

Relationships of red-cockaded woodpecker reproduction and foraging habitat characteristics in Arkansas and Louisiana

Red-cockaded woodpecker (RCW; Picoides borealis) productivity is influenced by characteristics of forests in which they forage. Thus, we investigated the relationships between stand conditions and RCW reproduction. We conducted focal animal sampling two to three times per season for ten RCW groups from September 1999–September 2001 in southern Arkansas and northern Louisiana, USA. We measured overstory and understory vegetation characteristics associated with observed foraging sites. Mean diameter at breast height (DBH) of hardwood trees and autumn forb cover were inversely correlated with number of eggs laid. The numbers of eggs, hatchlings, and fledglings were similar between groups with and without helpers, though helpers tended to remain in higher quality habitat. Groups with helpers used foraging areas with greater basal area of pines (Pinus spp.) ≥25.4 cm DBH, conifer canopy cover, leaf litter cover, litter depth, autumn vine cover, and winter woody cover than groups without helpers. Our results suggested that foraging habitat recommendations should include understory conditions, although additional research is required to clarify the interrelationships between RCW reproduction, forest stand characteristics, and the arthropod community.     

Activation of protein kinase isoenzymes under near physiological conditions. Evidence that both types (A and B) of cAMP binding sites are involved in the activation of protein kinase by cAMP and 8-N3-cAMP

cAMP-dependent protein kinase I and II (cAKI and cAKII) were incubated under near physiological conditions in the presence of various concentrations of 8-N3-c[3H]AMP or c[3H]AMP. Both types (A and B) of cyclic nucleotide binding sites of cAKI or cAKII were occupied to a similar extent and the degree of their occupation correlated with the degree of kinase activation. cAKI and cAKII bound cAMP in an apparent positively cooperative manner in the presence of Mg2+, ATP. 8-N3-c[3H]AMP dissociated several orders of magnitude faster from site A than site B of the regulatory moiety of cAKII, and was photo-incorporated only when bound to site B.     

Kinetic investigations on the phase transition of phospholipid bilayers

Pressure-jump experiments were performed on vesicles and liposomes of dimyristoyl phosphatidylcholine and dipalmitoyl phosphatidylcholine following the time course of solution turbidity. For both lipids two relaxation effects were evaluated the time constants of which exhibit clear maxima at the midpoint of the phase transition. The time constants lie for vesicles in the 100 μs and 1 ms ranges and for liposomes in the 1 ms and 10 ms ranges. The processes are slightly faster for dimyristoyl phosphatidylcholine than for dipalmitoyl phosphatidylcholine. All relaxation times are concentration-independent. The time constant and amplitude behaviours indicate that all processes are cooperative in agreement with previous interpretations. It is demonstrated that cooperative units can be evaluated from the relaxation amplitudes. These are of the same order of magnitude as those obtained from static experiments. On the grounds of the present kinetic investigation we can state that the application of the linear Ising model to two-dimensional processes as attempted for the static lipid phase transition is inadequate.