Aristotle's study of the animal world: the case of the kobios and phucis

Aristotle was a remarkable observer of the living world. He made detailed observations on the anatomy and life history characteristics of many organisms as part of a larger study into the differentiae (diaphora) of groups of animals. This reexamination of Aristotle's observations of two small fishes is a study into the work or the way of being of particular organic wholes. As such, it is directed by three main objectives: to evaluate the accuracy of those observations Aristotle makes with regard to the kobios and phucis in the History of Animals, as well as to understand how he might have conducted his research; to determine whether aspects of those observations would ground more philosophical arguments; and to contribute to the understanding of the basic biology of these fishes. In so doing, this article also may introduce a new generation of biologists to the richness of Aristotle's biological observations and the questions that motivated them.     

Positioning the genome within the nucleus

Higher eukaryotic genomes contain both housekeeping genes and genes of which the expression is restricted to a defined time and space. It is well established that a correlation exists between structural organization of the genome and gene expression control. The functional mechanisms underlying this correlation are still poorly understood. Here I describe several observations that are the basis of present concepts of genome organization and nuclear architecture related to functionality. Regarding the relationship between positioning and disturbed cell functionality, I describe observations showing that the proximity of selected gene loci is statistically correlated with their propensity for oncogenic translocations as well as observations of patterns occurring in neurodegenerative disorders where unstable repeats are translated into an expanded polyglutamine tract. Such observations underscore the importance to understand how genetic perturbations lead to the global reorganization of nuclear architecture, chromatin structure and widespread changes in gene expression.     

Masking unmasked in the proportional hazards model

Influence measures based on the pairwise deletion approach and the differentiation approach are developed for unmasking observations masked by other observations in the proportional hazards model. These influential observations might have substantial impact on statistical inference and might provide important information for model adequacy. One numerical example based on real data is presented and discussed.     

大数据时代下的生态系统观测发展趋势与挑战

随着观测技术的发展, 生态学研究尺度不断扩大。生态系统观测从小规模合作、短时间个人观测向大规模、长时间、跨学科、多因子联合观测转变。传感器技术的革新带来了生态观测在时空尺度的扩展与精确度上的提升, 致使生态学观测数据的容量、产生速度与数据种类飞速增长。对生态系统数据获取、存储与管理的传统方法无疑不再能满足现代生态学研究的要求。因此, 我们建议以大数据时代的数据存储、管理与处理技术为基础, 整合生态物联观测网络(Internet of Ecology)、公民科学观测网络以及基于标准化数据管理的研究者网络互联, 建立整合生态系统观测平台来应对这一困境。为生态学研究者打造一站式生态观测服务, 是大数据时代下生态系统观测的大势所趋。     

Information in Observation Under the Correlated Linear Model

In this paper we propose a measure of information in a set of observations under a given design and the linear model with the observations being correlated. We then compare the different sets of observations with respect to the information measure in the situations where the underlying designs are nested and split-plot. AMS 1970 Subject Classification: Secondary 62J05, 62J10, 62K05, 62K10, 62K15, 62K99.     

中国草原/荒漠植物多样性监测网 模式植物群落监测方案

“模式群落”是指能够反映某种植被分类单元基本特征, 并可作为准确描述该植被类型“标准”的典型植物群落。中国生物多样性监测网络——草原/荒漠植物多样性监测网旨在统一监测方法和技术规范的基础上, 在草原/荒漠植被主要群系分布的典型地段建立模式植物群落监测固定样方, 定期复查, 长期监测草原和荒漠的植物多样性变化。文章强调了典型植物群落监测是生物多样性监测的重要组成部分, 阐述了模式群落的概念, 介绍了草原/荒漠植物多样性监测网的总体思路和布局, 以及主要监测内容、方法、指标和预期产出。     

Analysis and description of the evolution of alginate immobilised cells systems

Different immobilised cells models, including very simple ones, can be useful in the fitting of experimental results. However, goodness or the ability to extrapolate results needs to be in accordance with basic observations and these will also suggest models to be proposed. In this paper, observations of calcium alginate/bacteria systems are used to show the ability of basic models to fit classic observations, as well as how new observations, in this case from electronic microscopy, oblige us to think about more complex mechanisms and mathematical treatments. Nevertheless it is not only important to discuss the model type, but also the type of kinetics assumed in the interior of the beads, as well as the internal structure, the boundary conditions related to bead shredding and cell escape and finally, geometrical effects.     

Traction fibres in chromosome movement: the pros and cons

The current discussion on the mechanism of chromosome movement in anaphase is dominated by a new hypothesis assuming active movement of the chromosome along stationary kinetochore microtubules. The aim of this article is to call attention to several older as well as to more recent observations on spindle structural dynamics and microtubule rearrangements which, in the author's opinion, cannot be explained by the new model. In fact, the observations seem to be more consistent with the classical concept of a traction fibre. For this reason, these observations should not be disregarded.     

Visible light observations on the kinetochore of the Indian muntjac, Muntiacus muntjac, Z

We report here a silver stain technique (Kt stain) for locating the kinetochore (centromere body) without concomitant staining of C-band material. We compare our observations with those obtained from C-banding, Cd (centromeric dot) banding, and electron micrographs, and we report preliminary observations on Indian muntjac centromeres.     

Observations on the timing of reproduction in the congeneric Comoro Island fruit bats, Pteropus livingstonii and P. seychellensis comorensis

Pteropus livingstonii (Gray 1866) is a highly endangered fruit bat of the Comoro Islands (Western Indian Ocean). Limited information on the bats' population biology is hampering conservation measures. During an expedition in 1992, observations were made on the timing of reproduction of P. livingstonii and the congeneric P. seychellensis comorensis (Nicoll, 1908): P. livingstonii breeds two months earlier than P. s. comorensis . These observations are discussed in relation to what is known about reproduction in Pteropus , and past observations on the Comorien Pteropus species.     

A note on the effect of observations with missing data on genetic correlation estimates

Summary Various studies have estimated covariance components as half the difference between the variance component of the sum of the variable values, for each observation, and the sum of the corresponding variable variance components. Although the variance components for the separate variables can be computed using all available data, the variance components of the sum can be computed only from those observations with records for both variables. Previous studies have suggested eliminating observations with missing data, because of possible selection bias. The effect of missing data on estimates of covariance components and genetic correlations was tested on sample beef cattle data and simulated data by randomly deleting differing proportions of records of one variable for each pair of variables analyzed. Estimates of genetic correlations computed with observations with missing data eliminated, were more accurate than estimates computed using all available data. Furthermore, when observations with missing data were included, estimates of genetic correlation far outside the parameter space were common. Therefore, this method should be used only if observations with missing data have been eliminated.     

Use of zoospore concentrations and life cycle parameters in determining the population of anaerobic fungi in the rumen ecosystem

An indirect approach to quantification of the fibrolytic anaerobic fungi in the rumen is described. A mathematical model of the life cycle of anaerobic fungi, based upon observations of the life histories and growth kinetics of these organisms in vitro and in vivo, is constructed and solved in the steady-state to determine the population of particle-attached (substrate-associated) fungal thalli from the concentration of free-swimming zoospores in rumen liquid. The values obtained are broadly consistent with ruminal observations and with observations on faecal populations, which assume that a significant proportion of fungi leaving the rumen (as cysts or spores) can ultimately be accounted for in the faeces.     

Recent sightings of the bowhead whale (Balaena mysticetus) in Northeast Greenland and the Greenland Sea

By the end of the 19th century, European whalers had brought the bowhead whale (Balaena mysticetus) in the “Spitsbergen stock” ranging the waters between eastern Greenland and the western Russian Arctic to the verge of extinction. This paper presents observations of this species in Northeast Greenland and in the Greenland Sea between 1940 and 2004. The number of observations has increased in Northeast Greenland since the mid-1980s. Only three observations are known for the period 1940–1979 but during the 1980s, the 1990s and between 2000 and 2004, six, six and eight observations of bowhead whales were made, involving an absolute minimum of three, five and eight to ten different individuals, respectively. It remains uncertain whether this represents an increase in survey effort, an immigration from other areas, a recent recovery of an eastern Greenland relict “tribe” belonging to the Spitsbergen stock, or a combination of these factors.     

Differences in the diet of the male and female tui (Prosthemadera novaeseelandiae: Meliphagidae)

Abstract

Tui are shown to be highly nectarivorous but observations show differences in degree of importance between the three food categories; nectar, fruit and arthropods, according to season. Foraging observations were significantly different for male and female tui during spring and especially during autumn, with males taking more nectar and females taking more arthropods.     

Optimal crossover designs in the presence of carryover effects

Under either the random patient-effect model with sequence effects or the fixed patient-effect model, the usual two-period, two-treatment crossover design, AB,BA, cannot be used to estimate the contrast between direct treatment effects when unequal carryover effects are present. If baseline observations are available, the design AB,BA can validly be used to estimate a treatment contrast. However, the design AB,BA,AA,BB with baseline observations is more efficient. In fact, we show that this design is optimal whether or not baseline observations are available. For experiments with more than two periods, universally optimal designs are found for both models, with and without carryover effects. It is shown that uncertainty about the presence of carryover effects is of little or no consequence, and the addition of baseline observations is of little or no added value for designs with three or more periods; however, if the experiment is limited to only two periods the investigator pays a heavy penalty.     

North American vegetation patterns observed with the NOAA-7 advanced very high resolution radiometer

Spectral vegetation index measurements derived from remotely sensed observations show great promise as a means to improve knowledge of land vegetation patterns. The daily, global observations acquired by the Advanced Very High Resolution Radiometer, a sensor on the current series of U.S. National Oceanic and Atmospheric Administration meteorological satellites, may be particularly well suited for global studies of vegetation. Preliminary results from analysis of North American observations, extending from April to November 1982, show that the vegetation index patterns observed correspond to the known seasonality of North American natural and cultivated vegetation. Integration of the observations over the growing season produced measurements that are related to net primary productivity patterns of the major North American natural vegetation formations. Regions of intense cultivation were observed as anomalous areas in the integrated growing season measurements. These anomalies can be explained by contrasts between cultivation practices and natural vegetation phenology. Major new information on seasonality, annual extent and interannual variability of vegetation photosynthetic activity at continental and global scales can be derived from these satellite observations.This research is in part supported through NASA Cooperative Agreement NCC 5–26 from the NASA/Goddard Space Flight Center.     

The significance of a differential distribution of alkaline phosphatase in the perichondrium of the mandibular condylar cartilage in the wistar albino rat

Summary The aim of the present investigation has been to further study an incidentally observed rare distribution of alkaline phosphatase in the covering of the mandibular condyle. It was felt that this phenomenon might be related to the necessary interaction between the bony and the cartilaginous condylar head during the transformative growth movements of the condylar process.The study has been based on histomorphological and histochemical observations on frontal and sagittal sections of mandibular condyles from rats between 10 and 21 days of age. As regards the bony condylar head which is oval with its long axis in the antero-posterior direction the observations showed that this structure during growth is transformed in a superior, posterior and medial direction. This involves differential resorption on the surfaces in the anterior part and differential apposition on the surfaces in the posterior part.As regards the cartilaginous condylar head, the observations showed that its shape in the frontal plane changes from triangular in the anterior part to rectangular in the posterior part. Alkaline phosphatase reaction in its perichondrium always reaches a higher level medially than laterally.General observations of perichondrial alkaline phosphatase reaction were applied to the distribution of the enzyme in the perichondrium of the mandibular condyle. These data suggest that as the condylar cartilage grows medially, it becomes narrower anteriorly and broader posteriorly.     

Field studies on the effect of cattle skin secretion on the behaviour of tsetse

Abstract. The effect of ox skin secretions (sebum) on the behaviour of tsetse flies, Glossina spp., was investigated in the field using electrified targets, some of which operated intermittently, and by direct observations of flies landing on treated and untreated cloth. As the off-period of an intermittently operating electrified target increased, the catch decreased both with and without the sebum present. Targets with sebum always caught more flies than targets without sebum, but there was no evidence to suggest that sebum increased the duration of stay on a target. Direct observations of flies on cloth targets revealed that for both species the presence of sebum reduced the duration of contact and for G. pallidipes the number of return contacts was increased. The results from direct observations were used to predict the number of repeat landings that would need to be made by flies in order to account for the catch of tsetse at intermittently electrified targets.     

Some observations on the spawning behaviour and larval development in the limpet,Cellana Radiata (Born) (Gastropoda: Prosobranchia)

Some observations were made on the spawning behaviour, fertilization and larval development from fertilization to the veliger stage in the common tropical limpet Cellana radiata, of the Visakhapatnam coast. Attempts have also been made to compare the present observations with those in the temperature climate limpets.