Statistical detection of multiscale landscape patterns

Detection of discontinuities in landscape patterns is a crucial problem both in ecology and in environmental sciences since they may indicate substantial scale changes in generating and maintaining processes of landscape patches. This paper presents a statistical procedure for detecting distinct scales of pattern for irregular patch mosaics using fractal analysis. The method suggested is based on a piecewise regression model given by fitting different regression lines to different ranges of patches ordered according to patch size (area). Proper shift-points, where discontinuities occur, are then identified by means of an iterative procedure. Further statistical tests are applied in order to verify the statistical significance of the best models selected. Compared to the method proposed by Krummel et al. (1987), the procedure described here is not influenced by subjective choices of initial parameters. The procedure was applied to landscape pattern analysis of irregular patch mosaics (CORINE biotopes) of a watershed within the Map of the Italian Nature Project. Results for three different CORINE patch types are herein presented revealing different scaling properties with special pattern organizations linked to ecological traits of vegetation communities and human disturbance.     

Allozyme variation in global populations of striped mullet, Mugil cephalus (Pisces: Mugilidae)

The striped mullet, Mugil cephalus Linnaeus, 1758, is one of the few species of marine shore fish with a worldwide circumtropical distribution. Because of this distribution and the dependency of M. cephalus on coastal waters during various phases of its life cycle, as well as nearshore living habits, questions have been raised regarding levels of genetic divergence and gene flow among transoceanic populations. To cast more light on this, allozyme variation at 27 presumptive gene loci was investigated in ten globally diverse populations. The observed heterozygosity ranged from 0.018 (Hawaii) to 0.081 (Florida), averaging 0.050. The proportion of polymorphic loci showed a similar trend. Several populations were characterised by fixed allelic differences. Estimated gene diversities were very high, the allele frequency variation among populations was found to be 68%; genetic distances reached 0.242, with an average of 0.117. Estimated rates of gene flow were high among Mediterranean populations (Nm = 7.26), and between Mediterranean and East Atlantic populations (Nm= 2.86), but extremely low between non-contiguous populations within the Indian, Pacific and Atlantic Oceans, where Nm ranged from 0.03 to 0.05. Received: 7 April 1997 / Accepted: 4 February 1998     

Different behaviours in the solubilization of polycyclic aromatic hydrocarbons in water induced by mixed surfactant solutions

Water solubility of polycyclic aromatic hydrocarbons (PAHs), viz, naphthalene and phenanthrene, in micellar solutions at 25 °C was investigated, using two series of different binary mixtures of anionic and nonionic surfactants. Tween 80 and Brij-35 were used as nonionic surfactants whereas fatty acids or amphiphilic cyclodextrins (Mod-β-CD) synthesized in our laboratory were used as anionic ones. Solubilization capacity has been quantified in terms of the molar solubilization ratio and the micelle-water partition coefficient, using UV-visible spectrophotometry. Anionic surfactants exhibited less solubilization capacity than nonionics. The mixtures between Tween 80 and Mod-β-CD did not show synergism to increase the solubilization of PAHs. On the other hand, the mixtures formed by Tween 80 and fatty acids at all mole fractions studied produced higher enhancements of the solubility of naphthalene than the individual surfactants. The critical micellar concentration of the mixtures of Tween 80/sodium laurate was determined by surface tension measurements and spectrofluorimetry using pyrene as probe. The system is characterized by a negative interaction parameter (β) indicating attractive interactions between both surfactants in the range of the compositions studied.     

Moderating effects of political skill,perceived control,and job‐related self‐efficacy on the relationship between negative affectivity and physiological strain

The present study examined whether employees high in negative affectivity (NA) are destined to experience strain at a higher level than those low in NA. We used data collected from 230 employees to investigate the moderating effects of political skill, as a form of interpersonal control, on the relationship between NA and physiological strain. As hypothesized, NA was positively related to physiological strain (i.e., facial muscle tension as measured by electromyography (EMG)), and political skill buffered this effect such that the relationship was weaker among employees who were higher in political skill. Tests of mediated moderation further suggested the means by which political skill moderates the NA/strain relationship; specifically, the results were consistent with the idea that perceived control and, in turn, job‐related efficacy explain the moderating effect of political skill. Strengths and limitations of the study, practical implications, and directions for future research are discussed. Copyright © 2007 John Wiley & Sons, Ltd.     

Workplace offense and victims' reactions: the effects of victim‐offender (dis)similarity,offense‐type,and cultural differences

This study examined the effects of workplace offenders' characteristics and offense‐type on victims' reactions. Responses from 352 employed graduate students in the U.S. and South Korea to a hypothetical offense incident revealed that employees from the U.S. and Korea differ in their expressed desirability of avoiding, seeking revenge against, and reconciling with an offending coworker depending on the offenders' similarity/dissimilarity to the victim and on the type of offense. As expected, Koreans (but not U.S. Americans) were more likely to avoid and to seek revenge on a coworker whose offensive remark was group‐ rather than personally‐directed. In addition, Koreans were most motivated to reconcile when an offensive remark came from a similar rather than dissimilar coworker and when the offense targeted them personally (not their group). However, U.S. Americans were most motivated to reconcile when an offensive remark came from a similar rather than dissimilar other and when the offense targeted their group (not them personally). Copyright © 2008 John Wiley & Sons, Ltd.     

Industrial Farm Animal Production: A Comprehensive Moral Critique

Over the past century, animal agriculture in the United States has transformed from a system of small, family farms to a largely industrialized model—often known as ‘industrial farm animal production’ (IFAP). This model has successfully produced a large supply of cheap meat, eggs and dairy products, but at significant costs to animal welfare, the environment, the risk of zoonotic disease, the economic and social health of rural communities, and overall food abundance. Over the past 40 years, numerous critiques of IFAP have been published, for both academic and non-academic audiences, mostly focusing on our obligations to animals. Here we offer a comprehensive critique of IFAP, focusing not only on our obligations to animals, but also important environmental, social, economic, and public health concerns. Our cumulative argument proceeds in five steps: (1) we briefly review the structure and key characteristics of IFAP; (2) we review the adverse effects of IFAP; (3) we review the historical development and positive rationale for IFAP; (4) we summarize previous moral critiques of IFAP, as well as defenses of it; and (5) we offer a moral critique of IFAP based on the common morality, and in particular on a principle of nonmaleficence, which we take to be the least controversial argument.     

Chemical self-organization in self-assembling biomimetic systems

Far-from-equillibrium oscillating chemical reactions are among the simplest systems showing complex behaviors and emergent properties. This class of reactions is often employed to mimic and understand the mechanisms of a great variety of biological processes. In this context, pattern formation due to the coupling between reaction and transport phenomena represent an active and promising research area. In this paper, we present results coming from experiments where we tried to blend the structural properties of self-assembled matrixes (sodium dodecyl sulphate micelles and phospholipid bilayers) together with the evolutive peculiarities of the Belousov–Zhabotinsky reaction. A series of interesting dynamical behaviors, like spatio-temporal chaos, stationary patterns and segmented waves, were found in reaction–diffusion and reaction–diffusion–convection experiments.     

Insecticides biomarker responses on a freshwater fish Corydoras paleatus (Pisces: Callichthyidae)

This study was undertaken to investigate the effects of sublethal concentration of three different classes of insecticides (carbamate, organophosphate, and pyrethroid compounds) on the freshwater fish Corydoras paleatus. For this purpose, fish were exposed for 96 hours to commercial pesticides. Different biomarkers were analyzed as levels of lipid peroxidation (LPO), piscine micronucleus test, and enzymatic activities of catalase (CAT), glutathione S-transferase (GST), and acetylcholinesterase (AChE). The brain AChE was inhibited with carbaryl and methyl parathion, but no inhibition was observed with deltamethrin. The insecticides did not cause oxidative stress or genotoxic effects at the tested concentrations. Further studies are needed to elucidate the biotransformation of Corydoras paleatus insecticides and a possible resistance mechanism.     

Autocorrelation offsets zero-inflation in models of tropical saplings density

Modelling the local density of tropical saplings can provide insights into the ecological processes that drive species regeneration and thereby help predict population recovery after disturbance. Yet, few studies have addressed the challenging issues in autocorrelation and zero-inflation of local density. This paper presents Hierarchical Bayesian Modelling (HBM) of sapling density that includes these two features. Special attention is devoted to variable selection, model estimation and comparison.