Costs of infant‐carrying in the cotton‐top tamarin (Saguinus oedipus)

Infant‐carrying behavior among callitrichids seems to be a costly activity. Costs have been related to the physical efforts of carrying the weight of very heavy infants and to the resulting reduction in foraging efficiency. However, the costs of carrying in terms of the physical consequences for carriers have not previously been assessed. In this study, we have regarded weight loss in infant carriers as a measure of costs. We studied five families of cotton‐top tamarins (Saguinus oedipus) during the first 9 weeks following the birth of infants. Captive‐breeding conditions were required so that body weight could be measured frequently. To avoid inflicting undue stress on the subject animals, we used a noninvasive method for weighing the tamarins. Differences in carrying contribution were found amongst fathers and male and female helpers, with female helpers contributing less. We have found that carrying infants in the cotton‐top tamarins is an activity that produces a weight loss. Fathers and male helpers go through a maximal body weight loss. While carrying, the tamarins also decrease food intake. However, no relationship was found between contribution to carrying and feeding time or in energetic intake during feeding observations. Thus, it seems that a direct relation doesn't exist between the observations of feeding and weight loss. Fathers increase their contribution to carrying during mothers' periovulatory periods. In this period, male helpers and especially fathers go through a maximal body weight loss. We found body weight losses of up to 11.3% in one subadult male and 9.1percnt; in a father during the fifth week. No changes occurred in food intake in fathers or other male helpers during this period. During periovulatory periods, mothers carried less frequently but did increase their food intake. They gained weight from the second week after birth onward, especially during the periovulatory period. It seems that the infant‐carrying behavior of fathers and male helpers may contribute to the improvement of the mothers' physical condition after birth and therefore may support a consecutive pregnancy. Am. J. Primatol. 48:99–111, 1999. © 1999 Wiley‐Liss, Inc.     

Linkage mechanisms in the vertebrate skull: Structure and function of three‐dimensional,parallel transmission systems

Many musculoskeletal systems, including the skulls of birds, fishes, and some lizards consist of interconnected chains of mobile skeletal elements, analogous to linkage mechanisms used in engineering. Biomechanical studies have applied linkage models to a diversity of musculoskeletal systems, with previous applications primarily focusing on two‐dimensional linkage geometries, bilaterally symmetrical pairs of planar linkages, or single four‐bar linkages. Here, we present new, three‐dimensional (3D), parallel linkage models of the skulls of birds and fishes and use these models (available as free kinematic simulation software), to investigate structure–function relationships in these systems. This new computational framework provides an accessible and integrated workflow for exploring the evolution of structure and function in complex musculoskeletal systems. Linkage simulations show that kinematic transmission, although a suitable functional metric for linkages with single rotating input and output links, can give misleading results when applied to linkages with substantial translational components or multiple output links. To take into account both linear and rotational displacement we define force mechanical advantage for a linkage (analogous to lever mechanical advantage) and apply this metric to measure transmission efficiency in the bird cranial mechanism. For linkages with multiple, expanding output points we propose a new functional metric, expansion advantage, to measure expansion amplification and apply this metric to the buccal expansion mechanism in fishes. Using the bird cranial linkage model, we quantify the inaccuracies that result from simplifying a 3D geometry into two dimensions. We also show that by combining single‐chain linkages into parallel linkages, more links can be simulated while decreasing or maintaining the same number of input parameters. This generalized framework for linkage simulation and analysis can accommodate linkages of differing geometries and configurations, enabling novel interpretations of the mechanics of force transmission across a diversity of vertebrate feeding mechanisms and enhancing our understanding of musculoskeletal function and evolution. J. Morphol. 277:1570–1583, 2016. © 2016 Wiley Periodicals, Inc.     

Living on the edge: life‐history of olive baboons at Gashaka‐Gumti National Park,Nigeria

Baboons are the most successful and ubiquitous African primates, renowned for their behavioral and reproductive flexibility, which enable them to inhabit a wide variety of habitat types. Owing to a number of long‐term field studies, comparative behavioral, developmental, demographic, and life‐history data are available from several populations, but study sites show a heavy bias toward South and East African savannahs, with little research in West or Central Africa. Life‐history data from such areas are important if we are fully to understand the nature of the environmental factors that limit baboon distribution. Here, we present demographic data for olive baboons at Gashaka‐Gumti National Park (GGNP), Nigeria, collected from December 2000–February 2006, and use these data to test comparative models of baboon life‐history. The GGNP habitat, which includes large areas of rainforest, is an environment in which baboons are little studied, and rainfall is much higher than at previous study sites. GGNP troop size data are presented from censuses, as well as life‐history data for two troops, one of which is within the park and wild‐feeding (Kwano troop), whereas the other dwells at the park edge, and supplements its diet by crop‐raiding (Gamgam troop). Troop sizes at GGNP are small compared with other field sites, but fit within previously suggested ranges for baboons under these climatic conditions. Inter‐birth intervals in Kwano troop were long compared with most studied populations, and values were not as predicted by comparative models. Consistent with known effects of food enhancement, Gamgam troop experienced shorter inter‐birth intervals and lower infant mortality than Kwano troop. We indicate some possible factors that exclude baboons from true rainforest, and suggest that the clearing of forests in Central and West Africa for agricultural land may allow baboons to extend their range into regions from which they are currently excluded. Am. J. Primatol. 71:293–304, 2009. © 2009 Wiley‐Liss, Inc.     

环渤海沿海地区土地承载力时空分异特征

沿海地区是中国未来社会经济发展的重点区域,近年来沿海地区人地矛盾越来越突出,研究沿海地区土地承载力具有重要意义。针对以往评价中的不足,采用韦伯-费希纳定律确定指标评价标准;利用D-S证据理论进行主客观综合权重的计算,运用可变模糊集理论及模型对土地承载力进行综合评价,并以环渤海沿海地区进行实例分析。研究结果表明,2000—2011年,环渤海地区土地承载力整体呈持续上升趋势,但空间分布差异显著,天津、唐山、大连、盘锦、青岛、烟台、东营、威海土地承载力相对较高,锦州、营口、秦皇岛、滨州、潍坊、日照属于中等水平,沧州、丹东、葫芦岛四市土地承载力相对较低。可变模糊评价模型应用于土地承载力评价,计算简便,可操作性强,评价结果可信度高。     

甘肃省资源环境承载力时空分异

从经济、社会、环境和资源4个子系统中选取24个指标构建区域资源环境承载力评价体系,运用加权TOPSIS模型结合GIS的空间分析功能从时间和空间维度对甘肃省14个市州2004—2013年的综合承载力和4个子系统内部承载力水平进行剖析。研究表明:(1)近10年甘肃省各市州资源环境综合承载力指数呈低水平上的平稳态势,与经济发展水平一致;呈西北高东南低的空间格局和金字塔形的层次结构。嘉峪关市居第1层;金昌市、兰州市、酒泉市居第2层;其他市州居第3层;(2)各子系统对资源环境综合承载力的影响不同。生态环境子系统的承载力对资源环境综合承载力贡献最大,明显高于其他3系统,经济系统贡献很小;(3)各市州各子系统承载力指数存在明显的时空分异。经济支撑力指数呈河西(除武威外)和兰州高,东南和南部低的空间格局,呈现金字塔形的层次结构整体偏低变化较小。社会承载力指数除金昌市有较大的突变外各市区都比较平稳,空间上呈河西(除武威外)和兰州高,东南、南部低的空间格局;嘉峪关市、兰州、酒泉3市较高,其余各地都较低。环境承载力指数变动频繁,波动幅度不大,空间上基本呈两头高中间低的哑铃状空间格局。资源承载力指数偏低,武威、庆阳、定西、甘南、临夏和天水6市州指数曲线平稳,其余8市州波动频繁,波动幅度大,空间上呈河西地区(除武威外)和陇南市高,其余各州市低的集中分布格局。     

Diet‐induced early‐stage atherosclerosis in baboons: Lipoproteins,atherogenesis, and arterial compliance

Background

The purpose of this study was to determine whether dietary manipulation can reliably induce early‐stage atherosclerosis and clinically relevant changes in vascular function in an established, well‐characterized non‐human primate model.

Methods

We fed 112 baboons a high‐cholesterol, high‐fat challenge diet for two years. We assayed circulating biomarkers of cardiovascular disease (CVD) risk, at 0, 7, and 104 weeks into the challenge; assessed arterial compliance noninvasively at 104 weeks; and measured atherosclerotic lesions in three major arteries at necropsy.

Results

We observed evidence of atherosclerosis in all but one baboon fed the two‐year challenge diet. CVD risk biomarkers, the prevalence, size, and complexity of arterial lesions, plus consequent arterial stiffness, were increased in comparison with dietary control animals.

Conclusions

Feeding baboons a high‐cholesterol, high‐fat diet for two years reliably induces atherosclerosis, with risk factor profiles, arterial lesions, and changes in vascular function also seen in humans.     

Copula‐based semiparametric models for spatiotemporal data

The joint analysis of spatial and temporal processes poses computational challenges due to the data's high dimensionality. Furthermore, such data are commonly non‐Gaussian. In this paper, we introduce a copula‐based spatiotemporal model for analyzing spatiotemporal data and propose a semiparametric estimator. The proposed algorithm is computationally simple, since it models the marginal distribution and the spatiotemporal dependence separately. Instead of assuming a parametric distribution, the proposed method models the marginal distributions nonparametrically and thus offers more flexibility. The method also provides a convenient way to construct both point and interval predictions at new times and locations, based on the estimated conditional quantiles. Through a simulation study and an analysis of wind speeds observed along the border between Oregon and Washington, we show that our method produces more accurate point and interval predictions for skewed data than those based on normality assumptions.     

Development of parameters influencing blood oxygen carrying capacity in the welcome swallow and fairy martin

Welcome swallow (Hirundo neoxena) and fairy martin (Petrochelidon ariel) nestlings develop relatively slowly. They exceed adult mass early in development, then lose weight and fledge at about adult mass, i.e. have a mass-overshoot-recession (Mor) growth profile. Development of parameters influencing blood oxygen carrying capacity (O2Cap) was documented to determine if O2Cap also reached a plateau substantially before fledging or increased continuously throughout nestling development. Hematocrit (Hct), erythrocyte count (RBC) and whole blood haemoglobin (Hb) increased 1.8- to 2.8-fold, so that O2Cap doubled during development in both species. Increase in Hct, Hb and RBC was not continuous, peak values occurring well before fledging, in contrast to passerines with standard growth profiles in which the increase occurs throughout nestling development and peak values occur at fledging. However, the timing of O2Cap increase differed from that in some other Mor species (e.g. shearwaters). Mean erythrocyte volume (MCV) decreased linearly throughout development by 30-41%, but mean erythrocyte haemoglobin content (MCH) remained constant, so that mean erythrocyte haemoglobin concentration (MCHC) increased linearly 1.3- to 1.5-fold. Possible reasons for the apparent differences in the timing of O2Cap increase between rapidly and slowly growing altricial species and among MOR species are discussed.     

Behavioral measurement of temperament in male nursery‐raised infant macaques and baboons

We define temperament as an individual's set of characteristic behavioral responses to novel or challenging stimuli. This study adapted a temperament scale used with rhesus macaques by Schneider and colleagues [American Journal of Primatology 25:137–155, 1991] for use with male pigtailed macaque (Macaca nemestrina, n = 7), longtailed macaque (M. Fascicularis, n = 3), and baboon infants (Papio cynocephalus anubis, n = 4). Subjects were evaluated twice weekly for the first 5 months of age during routine removal from their cages for weighing. Behavioral measures were based on the subject's interactions with a familiar human caretaker and included predominant state before capture, response to capture, contact latency, resistance to tester's hold, degree of clinging, attention to environment, defecation/urination, consolability, facial expression, vocalizations, and irritability. Species differences indicated that baboons were more active than macaques in establishing or terminating contact with the tester. Temperament scores decreased over time for the variables Response to Capture and Contact Latency, indicating that as they grew older, subjects became less reactive and more bold in their interactions with the tester. Temperament scores changed slowly with age, with greater change occurring at younger ages. The retention of variability in reactivity between and within species may be advantageous for primates, reflecting the flexibility necessary to survive in a changing environment. Am. J. Primatol. 47:43–50, 1999. © 1999 Wiley‐Liss, Inc.     

Inverse‐probability‐of‐treatment weighted estimation of causal parameters in the presence of error‐contaminated and time‐dependent confounders

Inverse‐probability‐of‐treatment weighted (IPTW) estimation has been widely used to consistently estimate the causal parameters in marginal structural models, with time‐dependent confounding effects adjusted for. Just like other causal inference methods, the validity of IPTW estimation typically requires the crucial condition that all variables are precisely measured. However, this condition, is often violated in practice due to various reasons. It has been well documented that ignoring measurement error often leads to biased inference results. In this paper, we consider the IPTW estimation of the causal parameters in marginal structural models in the presence of error‐contaminated and time‐dependent confounders. We explore several methods to correct for the effects of measurement error on the estimation of causal parameters. Numerical studies are reported to assess the finite sample performance of the proposed methods.     

Heritability of age at first birth in captive olive baboons

The evolution of life history traits is a topic of growing interest in primatology. Traits associated with fertility, such as age at menarche and age at first birth, have great significance for natural selection, and knowing the genetic basis of such demographic traits may improve our understanding of population dynamics. Knowledge of the heritability of reproductive traits may also have practical implications for the management of captive breeding colonies. A maximum likelihood method was used to estimate heritability of age at first birth for a sample of female olive baboons resident at the Southwest Foundation for Biomedical Research. Only animals born at the Foundation that were caged in mixed sex groups and that had previously given birth were included in the sample (n = 316). There were 117 independent individuals and 199 individuals in 35 pedigrees composed of 2 to 26 members. Age at first birth ranged from 3.85 years to 13.11 years. Age at first birth is highly heritable (h² = 0.87) with no evidence for maternal effects or a dominance genetic component. This level of genetic variability in a fitness-related trait is contrary to evolutionary expectation and may reflect the uniform environment of a captive breeding situation. Thus, the heritability observed in this population may be taken as an upper bound for that in natural populations. © 1995 Wiley-Liss, Inc.     

LEVERS AND LINKAGES: MECHANICAL TRADE‐OFFS IN A POWER‐AMPLIFIED SYSTEM

Mechanical redundancy within a biomechanical system (e.g., many‐to‐one mapping) allows morphologically divergent organisms to maintain equivalent mechanical outputs. However, most organisms depend on the integration of more than one biomechanical system. Here, we test whether coupled mechanical systems follow a pattern of amplification (mechanical changes are congruent and evolve toward the same functional extreme) or independence (mechanisms evolve independently). We examined the correlated evolution and evolutionary pathways of the coupled four‐bar linkage and lever systems in mantis shrimp (Stomatopoda) ultrafast raptorial appendages. We examined models of character evolution in the framework of two divergent groups of stomatopods—“smashers” (hammer‐shaped appendages) and “spearers” (bladed appendages). Smashers tended to evolve toward force amplification, whereas spearers evolved toward displacement amplification. These findings show that coupled biomechanical systems can evolve synergistically, thereby resulting in functional amplification rather than mechanical redundancy.     

Generation and characterization of a mouse line carrying Reck‐CreERT2 knock‐in allele

Reck encodes a membrane‐anchored glycoprotein implicated in the regulation of extracellular metalloproteinases, Notch‐signaling, and Wnt7‐signaling and shown to play critical roles in embryogenesis and tumor suppression. Precise mechanisms of its actions in vivo, however, remain largely unknown. By homologous recombination, we generated a new Reck allele, Reck^CreERT2 (MGI symbol: Reck<tm3.1(cre/ERT2)Noda>). This allele is defective in terms of Reck function but expected to induce loxP‐mediated recombination in the cells committed to express Reck. Similarity in the expression patterns of the Reck^CreERT2 transgene and the endogenous Reck gene was confirmed in five tissues. In the adult hippocampus, induction of Reck expression after transient cerebral ischemia could be demonstrated using this allele. These results indicate the utility of this Cre‐driver allele in further studies.