Relationship between early puberty and the risk of hypertension/overweight at age 50: Evidence for a modified Barker hypothesis among Polish youth

The objective of this paper is to evaluate: (a) the association between BMI in childhood and adolescence and BMI at age 50, and (b) the association between timing of maturation at puberty and BMI at age 50 and the occurrence of high blood pressure. We explore whether differences in somatic and physiological factors observed among children with early or late onset of puberty indicates that this period of life could be critical for appearance of some CVD risk factors later in the life cycle. Our data include 135 males and 148 females, born in 1953, participants in the Wroc?aw Longitudinal Study. Data pertaining to their growth and several indices of sexual and skeletal maturation were collected yearly between age 8 and 18. Subsequently, their anthropometric traits were measured and cardiovascular health status was assessed at age 50. We find that BMI at distinct stages in the life cycle were positively correlated. Also BMI at 50 were positively associated with blood pressure at 50. Moreover, earlier maturation at puberty is associated with higher values of BMI at age 50. We also find that earlier pubertal maturation is an independent factor that influences the appearance of high blood pressure in adulthood.     

Microgravity dependence of excitable biological and physicochemical media

Neuronal tissue and especially the central nervous system (CNS) is an excitable medium. Self-organisation, pattern formation, and propagating excitation waves as typical characteristics in excitable media consequently have been found in neuronal tissue. The properties of such phenomena in excitable media do critically depend on the parameters (i.e., electromagnetic fields, temperature, chemical drugs) of the system and on small external forces to which gravity belongs. The spreading depression, a propagating excitation depression wave of neuronal activity, is one of the best described of the those wave phenomena in the CNS. Especially in the retina as a true part of the CNS it can be easily observed with optical techniques due to the high intrinsic optical signal of this tissue. Another of such waves in neuronal tissue is the propagating action potential in nerve fibres. In this paper, data from our laboratories concerning the influence of gravity on the velocity of propagating waves in excitable media are summarized mainly in terms of the retinal spreading depression and propagating action potentials. Additionally, we have used waves in gels of the Belousov-Zhabotinsky reaction as the physicochemical model system of biological activity as the properties of these waves follow the same theories as the spreading depression and action potentials and they have some striking similarities in wave behavior. Thus propagating Belousov-Zhabotinsky waves are described by their gravity dependence.     

两种雀形目鸟类的窝雏数处理实验:检验Lack假说

于1997—1999年在位于青海省北部的中国科学院海北高寒草甸生态系统定位站进行。选择地面筑巢的小云雀(Alauda gulgula)和灌丛筑巢的黄嘴朱顶雀(Acanthis flavirostris)为代表进行窝雏数处理实验。根据Lack假说的预报检验(1)常见窝卵数是否是最大生产力窝卵数;(2)窝雏数处理对雏鸟质量和亲鸟投入是否产生影响;(3)两种鸟的响应方式是否相同。其结果如下：①小云雀和黄嘴朱顶雀的常见窝卵数分别是3和5枚。年间变化不明显,用幼鸟出飞率作为生产力,两种鸟的扩增窝幼鸟出飞率下降,常见窝卵数(分布频率最高)等同于最大生产力窝卵数;②小云雀的幼鸟的生长参数不随窝雏数的改变而变化．而黄嘴朱顶雀有明显变化．说明窝雏数处理对后者幼鸟质量有明显影响。③用递食率作为亲鸟投资指标,小云雀亲鸟的递食率随窝雏数的增加而增加,但雏期不变;而黄嘴朱顶雀递食率不变,但雏期延长。④扩增窝雏数后,两种亲鸟表现出不同的响应方式,小云雀表现为提高单位时间递食次数,而黄嘴朱顶雀延长育幼时间。这两种方式不是通过影响雏鸟质量就是通过影响亲鸟存活率来降低子代和亲代的适合度。结果支持了自然选择将窝卵数调节到亲鸟能喂活最大数量子代的限度。即常见窝卵数就是最大生产力窝卵数的Lack假说。     

Effect of biologically active plants used as netst material and the derived benefit to starling nestlings

Summary The European starling Sturnus vulgaris preferentially incorporates fresh sprigs of particular plant species for use as nesting material. Chemicals found in these plants may act to reduce pathogen and ectoparasite populations normally found in nest environments. The present experiments were performed to test this Nest Protection Hypothesis. In the fild, we experimentally determined that wild carrot Daucus carota, a plant species preferred as nest material, effectively reduced the number of hematophagous mites found within nests relative to control nests without green vegetation. Chicks from nests containing wild carrot had higher levels of blood hemoglobin than chicks from control nests. However, there were no differences in weight or feather development. In the laboratory, we found that wild carrot and fleabane, Erigeron philadelphicus, (also preferred by starlings as nest material) substantially reduced the emergence of feeding instars of mites, while garlic mustard, Alliaria officinalis, (commonly available but not preferred) had little effect on the emergence of mites. We infer that preferred plant material may act to inhibit feeding or otherwise delay reproduction of mites, thereby reducing risk of anemia to developing nestlings.     

Panmixia across elevation in thermally sensitive Andean dung beetles

Janzen's seasonality hypothesis predicts that organisms inhabiting environments with limited climatic variability will evolve a reduced thermal tolerance breadth compared with organisms experiencing greater climatic variability. In turn, narrow tolerance breadth may select against dispersal across strong temperature gradients, such as those found across elevation. This can result in narrow elevational ranges and generate a pattern of isolation by environment or neutral genetic differentiation correlated with environmental variables that are independent of geographic distance. We tested for signatures of isolation by environment across elevation using genome‐wide SNP data from five species of Andean dung beetles (subfamily Scarabaeinae) with well‐characterized, narrow thermal physiologies, and narrow elevational distributions. Contrary to our expectations, we found no evidence of population genetic structure associated with elevation and little signal of isolation by environment. Further, elevational ranges for four of five species appear to be at equilibrium and show no decay of genetic diversity at range limits. Taken together, these results suggest physiological constraints on dispersal may primarily operate outside of a stable realized niche and point to a lower bound on the spatial scale of local adaptation.     

Biotic and abiotic factors driving the diversification dynamics of Crocodylia

Species diversity patterns are governed by complex interactions among biotic and abiotic factors over time and space, but are essentially the result of the diversification dynamics (differential speciation and extinction rates) over the long-term evolutionary history of a clade. Previous studies have suggested that temporal variation in global temperature drove long-term diversity changes in Crocodylia, a monophyletic group of large ectothermic organisms. We use a large database of crocodylian fossil occurrences (192 spp.) and body mass estimations, under a taxic approach, to characterize the global diversification dynamics of crocodylians since the Cretaceous, and their correlation with multiple biotic and abiotic factors in a Bayesian framework. The diversification dynamic of crocodylians, which appears to have originated in the Turonian (c. 92.5 Ma), is characterized by several phases with high extinction and speciation rates within a predominantly low long-term mean rate. Our results reveal long-term diversification dynamics of Crocodylia to be a highly complex process driven by a combination of biotic and abiotic factors which influenced the speciation and extinction rates in dissimilar ways. Higher crocodylian extinction rates are related to low body mass disparity, indicating selective extinctions of taxa at both ends of the body mass spectrum. Speciation rate slowdowns are noted when the diversity of the clade is high and the warm temperate climatic belt is reduced. Our finding supports the idea that temporal variations of body mass disparity, self-diversity, and the warm climate belt size provided more direct mechanistic explanations for crocodylian diversification than do proxies of global temperature.