Body size and area‐incidence relationships: is there a general pattern?

Aim This paper tests firstly for the existence of a general relationship between body size of terrestrial animals and their incidence across habitat patches of increasing size, and secondly for differences in this relationship between insects and vertebrates. Location The analysis was based on the occupancy pattern of 50 species from 15 different landscapes in a variety of ecosystems ranging from Central European grassland to Asian tropical forest. Methods The area‐occupancy relationship was described by incidence functions that were calculated using logistic regression. A correlation analysis between body size of the species and the patch area referring to the two given points of the incidence function was performed. In order to test for an effect of taxon (insects vs. vertebrates), an analysis of covariance was conducted. Results In all species, the incidence was found to increase with increasing patch area. The macroecological analysis showed a significant relationship between the incidence in habitat patches and the body size of terrestrial animals. The area requirement was found to increase linearly with increasing body size on a log‐log scale. This relationship did not differ significantly between insects and vertebrates. Conclusions The approach highlighted in this paper is to associate incidence functions with body size. The results suggest that body size is a general but rather rough predictor for the area requirements of animals. The relationship seems valid for a wide range of body sizes of terrestrial animals. However, further studies including isolation of habitats as well as additional species traits into the macroecological analysis of incidence functions are needed.     

Elektronenmikroskopische Untersuchungen an der Froschlunge

Zusammenfassung Das Alveolarepithel der Froschlunge weist nur einen einzigen Zelltyp auf. Die Zellkörper sitzen in den Nischen zwischen den Kapillaren, die sie mit Zytoplasmaausläufern überdecken. Die Epithelzellen enthalten große Zytosomen mit osmiophilen Lamellen mit einer Periode von 40–42 Å. Sie sind den Typ II-Pneumozyten der Säugerlunge vergleichbar.Das Alveolarepithel der Froschlunge ist mit einer Grenzschicht bedeckt, die in Abhängigkeit von der Fixierung eine 40–42 Å-Periode aufweist oder aus einer oder mehreren Doppelmembranen zusammengesetzt ist. Gittermuster und Myelinfiguren sind vorhanden. Das bedeutet, daß Surfactant in der Froschlunge in gleicher Weise wie in der Säugerlunge dargestellt werden kann.

---

Electron microscopic studies on the lung of the frogI. Demonstration of the alveolar lining layer (surfactant)

Summary The alveolar epithelium of the frog exhibits only one type of cells. The cell-bodies are situated in the spaces among the capillaries, which they cover with cytoplasmic extensions. The epithelial cells contain large bodies (cytosomes) with osmiophilic lamellae having a period of 40–42 Å. The alveolar cells are considered to be similar to the type II-pneumocytes of mammalian lungs.The alveolar epithelium of the lung of the frog is covered with a lining layer, which depending on the method of fixation consists of periods of 40–42 Å or of one or more double membranes. Lattice formations and myelin figures are seen. This means that the surfactant in the lung of the frog can be demonstrated in the same way as in mammalian lungs.

     

Respiratory system dynamical mechanical properties: modeling in time and frequency domain

The mechanical properties of the respiratory system are important determinants of its function and can be severely compromised in disease. The assessment of respiratory system mechanical properties is thus essential in the management of some disorders as well as in the evaluation of respiratory system adaptations in response to an acute or chronic process. Most often, lungs and chest wall are treated as a linear dynamic system that can be expressed with differential equations, allowing determination of the system’s parameters, which will reflect the mechanical properties. However, different models that encompass nonlinear characteristics and also multicompartments have been used in several approaches and most specifically in mechanically ventilated patients with acute lung injury. Additionally, the input impedance over a range of frequencies can be assessed with a convenient excitation method allowing the identification of the mechanical characteristics of the central and peripheral airways as well as lung periphery impedance. With the evolution of computational power, the airway pressure and flow can be recorded and stored for hours, and hence continuous monitoring of the respiratory system mechanical properties is already available in some mechanical ventilators. This review aims to describe some of the most frequently used models for the assessment of the respiratory system mechanical properties in both time and frequency domain.     

Schistocephalus solidus and Ligula intestinalis: Pinocytosis by the tegument

Using ruthenium red as a macromolecule, endocytosis was demonstrated in the plerocercoid of Ligula intestinalis and adult Schistocephalus solidus. Uptake, transport across the tegument, and exocytosis across the basal plasma membrane occurred within 6 min. The types of vesicles in the tegument of L. intestinalis are redescribed and their former classification is modified. The vertical and longitudinal distribution of pinosomes in the tegument of adult S. solidus and L. intestinalis plerocercoids were determined. The possible role of macromolecular uptake in the economy of pseudophyllidean tapeworms is discussed with particular reference to growth and defence of an unencysted larval stage in the tissues of the intermediate host.     

The reactivity of lactyl-oxythiamin implies the role of the amino-pyrimidine in thiamin catalyzed decarboxylation

It has previously been established that the deprotonated amino substituent of the pyrimidine of thiamin diphosphate (ThDP) acts as an internal base to accept the C2H of the thiazolium in ThDP-dependent enzymes. The amino group has also been implicated in assisting the departure of the aldehydic product formed after loss of CO₂ from ketoacid substrates. However, the potential role for the pyrimidine amino group in the key decarboxylation step has not been assessed. Oxythiamin contains a hydroxyl group in place of the pyrimidine amino group in thiamin, providing a basis for comparison of reactivity. Lactyl-oxythiamin (LOTh), the conjugate of pyruvic acid and oxythiamin was prepared by condensation of ethyl pyruvate and hydroxyl-protected oxythiamin followed by deprotection and acidic hydrolysis of the ethyl ester. The rate constants observed for the decarboxylation of LOTh in neutral and acidic solutions are about four times smaller than those for the corresponding compound that contains the amino group, lactylthiamin. The difference in reactivity is consistent with the amino group’s participation in facilitating the decarboxylation step by allowing a competitive addition pathway that produces bicarbonate and has implications for the corresponding enzymic reaction.     

A measure of spatial stratified heterogeneity

Spatial stratified heterogeneity, referring to the within-strata variance less than the between strata-variance, is ubiquitous in ecological phenomena, such as ecological zones and many ecological variables. Spatial stratified heterogeneity reflects the essence of nature, implies potential distinct mechanisms by strata, suggests possible determinants of the observed process, allows the representativeness of observations of the earth, and enforces the applicability of statistical inferences. In this paper, we propose a q-statistic method to measure the degree of spatial stratified heterogeneity and to test its significance. The q value is within [0,1] (0 if a spatial stratification of heterogeneity is not significant, and 1 if there is a perfect spatial stratification of heterogeneity). The exact probability density function is derived. The q-statistic is illustrated by two examples, wherein we assess the spatial stratified heterogeneities of a hand map and the distribution of the annual NDVI in China.     

Identification of soil quality indicators for assessing the effect of different tillage practices through a soil quality index in a semi-arid environment

Tillage is known to potentially affect soil quality in various ways. In this study, a soil quality index (SQI) was developed by quantifying several soil attributes either sensitive or insensitive to physical disturbance, using factor analysis as a dimension reduction technique, in order to discriminate different tillage systems. Soil properties including physical (MWD), chemical (pH, organic C, total N, available P and POM contents) and microbial (MBC, MBN, PCM, PNM and three enzymes) parameters were measured to establish a minimum data set (MDS) for the assessment of overall SQI. The soil attributes were determined on samples (0–20 cm depth) collected under moldboard (MP) and disk (DP) plows as conventional tillage (CT), and rotary (RP) and chisel (CP) plows as reduced tillage (RT) systems with a similar plant C input rate and cover crop over a period of six years (2005–2011) in a semi-arid calcareous soil (Calcixerepts) from Central Iran. Results indicated a clear difference in soil quality among the tillage systems with a significant increase of SQI under RT over time, particularly under CP practices. Although RT improved most soil microbial attributes, not all attributes contributed to SQI because of their close interrelationship. The final SQI consisted only of geometric mean of microbial activity (GMA, the square root of the product of PCM and PNM) and geometric mean of enzyme activity (GME, the cube root of the product of enzyme activities). Soil GME and GMA were found to be as key indicators contributing 55% and 36% to SQI, respectively. Therefore, the GME and GMA were the most important indicators effectively discriminating tillage systems, and could be used to monitor the enhancement of soil quality under RT in this semiarid environment. The influence of tillage year on SQI was greater than that of tillage practices. In conclusion, RT systems were characterized by a higher value of SQI, suggesting a good recovery of soil capacity and functions after abandoning CT in the studied area. Smallholder farmers should therefore be aware of the potential for high soil quality in future as a result of continuing RT systems, especially with surface tillage using CP practices.     

High resolution genetic mapping uncovers chitin synthase-1 as the target-site of the structurally diverse mite growth inhibitors clofentezine,hexythiazox and etoxazole in Tetranychus urticae

The acaricides clofentezine, hexythiazox and etoxazole are commonly referred to as ‘mite growth inhibitors’, and clofentezine and hexythiazox have been used successfully for the integrated control of plant mite pests for decades. Although they are still important today, their mode of action has remained elusive. Recently, a mutation in chitin synthase 1 (CHS1) was linked to etoxazole resistance. In this study, we identified and investigated a Tetranychus urticae strain (HexR) harboring recessive, monogenic resistance to each of hexythiazox, clofentezine, and etoxazole. To elucidate if there is a common genetic basis for the observed cross-resistance, we adapted a previously developed bulk segregant analysis method to map with high resolution a single, shared resistance locus for all three compounds. This finding indicates that the underlying molecular basis for resistance to all three compounds is identical. This locus is centered on the CHS1 gene, and as supported by additional genetic and biochemical studies, a non-synonymous variant (I1017F) in CHS1 associates with resistance to each of the tested acaricides in HexR. Our findings thus demonstrate a shared molecular mode of action for the chemically diverse mite growth inhibitors clofentezine, hexythiazox and etoxazole as inhibitors of an essential, non-catalytic activity of CHS1. Given the previously documented cross-resistance between clofentezine, hexythiazox and the benzyolphenylurea (BPU) compounds flufenoxuron and cycloxuron, CHS1 should be also considered as a potential target-site of insecticidal BPUs.     

Choice of Smoothing Parameters for Direct Kernels in Discrimination

Direct kernels, due to LAUDER (1983), as an alternative to the indirect kernel method in discriminant analysis are considered. It is shown that direct kernels may be based on any kernel function known in discrete density estimation. The choice of smoothing parameters is based on general loss functions and a family of loss functions which are specific for the discrimination problem is introduced. Examples with distance dependent and distance independent smoothing parameters are given to illustrate the applicability.