红腹锦鸡雏鸟的换羽研究

了解鸟类的换羽方式和顺序,对于研究鸟类的系统分类、生态及雏鸟的生长发育规律等方面,都具有重要的意义。     

眼镜蛇甲状腺结构的年周期变化律

本文报道眼镜蛇甲状腺结构的年周期变化规律;发现：（１）眼镜蛇甲状腺的滤泡、滤泡柱状上皮和吞饮泡的总数均值皆近似单峰曲线的年周期变化。滤泡、滤泡柱状上皮和吞饮泡的总数均值的高峰时间分别为６月１７日、５月２７日和５月３０日。眼镜蛇甲状腺结构３项指标总数均值的高峰期处于血浆ＴＳＨ浓度高峰期后,血浆Ｔ３,Ｔ４浓度高峰期前。     

Why are there no small species among xylem-sucking insects?

Xylem-sucking herbivores must cope with negative tension and extremely low nutrient concentration of xylem fluid. We test the hypothesis that the energetic cost of xylem fluid extraction grows with decreasing body size, as small species have relatively high metabolic rates and small feeding apparatus. The suction pressure gradient needed for feeding (P), calculated using Poiseuilles Law, and the cibarial pump load (L), estimated as xylem fluid volume per unit volume of cibarial muscles, were used to quantify energetic costs associated with feeding. Interspecific relationships between body size and frontoclypeus (cibarial pump) volume, proboscis length and food canal diameter were quantified using the structural relations model and model I (ordinary) regressions applied on species as data points (phylogeny ignored), and on independent (intrageneric) contrasts (taxonomy used as a surrogate of phylogeny). All the dimensions of feeding apparatus changed approximately isometrically with body volume. In consequence, the suction pressure gradient P (body volume)–0.21, and the cibarial pump load L (body volume)–0.17. These relationships result in an allometric change in energetic costs associated with xylem feeding. Energy needed to overcome the resistance of feeding apparatus (P) becomes negligible for any species longer than about 8mm, and there is an important decrease in the L values in species over about 17mm in body length. These allometric trends can result in large species having a wider range of potential (energetically profitable) host plants than small species. Analysis of body size distributions in xylem-feeding insects, which all belong to the Auchenorrhyncha (Hemiptera), showed that xylem feeders tend to be larger than phloem feeders, especially in terms of the minimum body size. Two evolutionary transitions from phloem to xylem feeding in Hemiptera were associated with an increase in the minimum body size. A possibility that the evolution of minimum body size in xylem feeders is energetically constrained is discussed.     

Determining Consistency of Spatial Dispersion of Nematodes in Small Plots

Nematode population densities in field plots were estimated by collecting samples consisting of 12 soil cores. Plots encompassed a variety of plant hosts and sampling dates, and provided data on the population densities of seven species of plant-parasitic nematodes. Three separate samples were collected per plot on each sampling date to obtain estimates of the mean and variance of numbers for each species. For each nematode species, these estimates were used to derive the Taylor''s Power Law regression over plots having identical hosts and sampling dates. For some nematode species, comparisons of regression equations among different sampling dates on the same host revealed similarities in values of a and b from Taylor''s Power Law. Parameters of Taylor''s Power Law relationships were used to develop sampling plans and to obtain estimates of sample precision. Precision estimates from specific and general sampling plans are illustrated for Belonolaimus longicaudatus.     

Systematics and body size: implications for feeding adaptations in New World monkeys.

The relationship between body size and feeding ecology is well established for primates. It is argued that the evolutionary history of modern New World monkeys and, in particular, the path to attainment of current body size is significant in understanding the similarities and differences between dietary strategies and other ecological parameters of similar-sized monkeys. Current interpretations of New World monkey evolutionary relationships are reviewed. Based on a synthesis of available body weights and the assumption that the earliest New World monkeys weighed close to 1 kg, similar to modern Aotus and Callicebus, predicted patterns of body size change in each lineage are given. Restrictions on directions of body size change in primates are discussed, and it is shown that "Stanley's Rule" offers a good explanation for differing body size ranges in New and Old World anthropoids. Predicted ecological correlates to body size drawn from the mammalian literature are offered and tested using data on New World monkeys, which show some concurrence and several interesting departures from predicted patterns. Sexual dimorphism in body weight of New World monkey species is reviewed, based on the new summary of body weight data given.     

Spectrophotometric method for high biomass concentration measurements

Continuous monitoring of concentration is important in the optimal control of bioreactors. Spectrophotometry provides a simple, accurate, and rapid way for measuring cell concentration of unicellular microorganisms, based on either Beer's law or calibration curves prepared using standard solutions. However, this method is limited to a low range of microbial concentrations, because Beer's law deviates significantly at high concentrations. In the present investigation, based on experimental work, a new technique is posed to monitor the concentration of microbial cells as high as 100 g DW/L. this is achieved by using a mixture of known concentration as reference, rather than the "ideal blank" with zero concentration of analyte. As a result, a new equation is developed that, although applied here only to microbial concentration, in principle can be used for monitoring the concentration of any optically sensitive material.     

Following autolysis in proteases by NMR: insights into multiple unfolding pathways and mutational plasticities

Recently there has been significant interest in deducing the form of the rate laws for chemical reactions occurring in the intracellular environment. This environment is typically characterized by low-dimensionality and a high macromolecular content; this leads to a spatial heterogeneity not typical of the well stirred in vitro environments. For this reason, the classical law of mass action has been presumed to be invalid for modeling intracellular reactions. Using lattice-gas automata models, it has recently been postulated [H. Berry, Monte Carlo simulations of enzyme reactions in two dimensions: Fractal kinetics and spatial segregation, Biophys. J. 83 (2002) 1891-1901; S. Schnell, T.E. Turner, Reaction kinetics in intracellular environments with macromolecular crowding: simulations and rate laws, Prog. Biophys. Mol. Biol. 85 (2004) 235-260] that the reaction kinetics is fractal-like. In this article we systematically investigate for the first time how the rate laws describing intracellular reactions vary as a function of: the geometry and size of the intracellular surface on which the reactions occur, the mobility of the macromolecules responsible for the crowding effects, the initial reactant concentrations and the probability of reaction between two reactant molecules. We also compare the rate laws valid in heterogeneous environments in which there is an underlying spatial lattice, for example crystalline alloys, with the rate laws valid in heterogeneous environments where there is no such natural lattice, for example in intracellular environments. Our simulations indicate that: (i) in intracellular environments both fractal kinetics and mass action can be valid, the major determinant being the probability of reaction, (ii) the geometry and size of the intracellular surface on which reactions are occurring does not significantly affect the rate law, (iii) there are considerable differences between the rate laws valid in heterogeneous non-living structures such as crystals and those valid in intracellular environments. Deviations from mass action are less pronounced in intracellular environments than in a crystalline material of similar heterogeneity.     

Phylogeny affects estimation of metabolic scaling in mammals

Abstract.— The relationship between body size and metabolic rate is a crucial issue in organismal biology and evolution. There has been considerable debate over whether the scaling exponent of the relationship is 0.75 (Kleiber's Law) or 0.67. Here we show that determination of this exponent for mammals depends on both the evolutionary tree and the regression model used in the comparative analysis. For example, more recent molecular-based phylogenies tend to support a 0.67 exponent, whereas older phylogenies, mostly based on morphological data, suggest a 0.75 exponent. However, molecular phylogenies yield more variable results than morphological phylogenies and thus are not currently helping to resolve the issue.     

Measuring and modelling plant area index in beech stands

For some beech (Fagus sylvatica L.) stands with different stand densities the plant area index (PAI) was measured by means of a Licor LAI-2000 plant canopy analyser. The stands are located on the slopes of a valley in south-west Germany and had been treated by different types of silvicultural management (heavy shelterwood felling, light shelterwood felling, control plot). The analyser was used (a) to investigate the light conditions on plots of the same thinning regime, (b) to quantify the differences between the different treatments and (c) to obtain absolute values of PAI for interdisciplinary research. PAI was measured at three different phenological stages (leafless, leaf-unfolding and fully leafed season in 2000) and was found to be about 5.2 for the fully developed canopy on the control plots, 3.2 on the light fellings and about 2.0 for the heavy fellings. In the leafless period PAI was between 1.1 (control) and 0.4 (heavy felling). Measurements made in summer 2000 and summer 2002 were compared, and showed an increase of PAI, especially on the thinned plots. Measurements of photosynthetically active radiation (PAR) above and below the canopy in combination with measured PAI were used to apply Beers Law of radiation extinction to calculate the extinction coefficient k for different sky conditions and for the different growing seasons on the control plots. The extinction coefficient k for the beech stands was found to be between 0.99 and 1.39 in the leafless period, 0.62 to 0.91 during leaf unfolding and between 0.68 and 0.83 in the fully leafed period. Using PAR measurements and the k values obtained, the annual cycle of PAI was modelled inverting Beers Law.     

Universalizing the Law of the Sea in the South China Sea Dispute

This article argues that a resolution of the maritime disputes in the South China Sea must be based upon a universalist framework where the maritime interests of the world are upheld. The article discusses the universalist framework of the 1982 United Nations Convention on the Law of the Sea (UNCLOS) and the universalist approach taken by the Tribunal on 12 July 2016 in the South China Sea Arbitration regarding the extinguishment of a state's “exceptionalist” maritime claims and the adoption of strict criteria for the characterization of features at sea.