Fine‐scale variation within urban landscapes affects marking patterns and gastrointestinal parasite diversity in red foxes

1. Urban areas are often considered to be a hostile environment for wildlife as they are highly fragmented and frequently disturbed. However, these same habitats can contain abundant resources, while lacking many common competitors and predators. The urban environment can have a direct impact on the species living there but can also have indirect effects on their parasites and pathogens. To date, relatively few studies have measured how fine‐scale spatial heterogeneity within urban landscapes can affect parasite transmission and persistence.
2. Here, we surveyed 237 greenspaces across the urban environment of Edinburgh (UK) to investigate how fine‐scale variation in socio‐economic and ecological variables can affect red fox (Vulpes vulpes) marking behavior, gastrointestinal (GI) parasite prevalence, and parasite community diversity.
3. We found that the presence and abundance of red fox fecal markings were nonuniformly distributed across greenspaces and instead were dependent on the ecological characteristics of a site. Specifically, common foraging areas were left largely unmarked, which indicates that suitable resting and denning sites may be limiting factor in urban environments. In addition, the amount of greenspace around each site was positively correlated with overall GI parasite prevalence, species richness, and diversity, highlighting the importance of greenspace (a commonly used measure of landscape connectivity) in determining the composition of the parasite community in urban areas.
4. Our results suggest that fine‐scale variation within urban environments can be important for understanding the ecology of infectious diseases in urban wildlife and could have wider implication for the management of urban carnivores.

     

Spatio‐temporal variation of salt marsh seedling establishment in relation to the abiotic and biotic environment

Contrary to our expectations, soil salinity and moisture explained little of the spatial variation in plant establishment in the upper intertidal marsh of three southern California wetlands, but did explain the timing of germination. Seedlings of 27 species were identified in 1996 and 1997. The seedlings were abundant (maximum densities of 2143/m² in 1996 and 1819/m² in 1997) and predominantly annual species. CCAs quantified the spatial variation in seedling density that could be explained by three groups of predictor variables: (1) perennial plant cover, elevation and soil texture (16% of variation), (2) wetland identity (14% of variation) and (3) surface soil salinity and moisture (2% of variation). Increasing the spatial scale of analysis changed the variables that best predicted patterns of species densities. Timing of germination depended on surface soil salinity and, to a lesser extent, soil moisture. Germination occurred after salinity had dropped below a threshold or, in some cases, after moisture had increased above a critical level. Between 32% and 92% of the seedlings were exotic and most of these occurred at lower soil salinity than native species. However, Parapholis incurva and Mesembryanthemum nodiflorum were found in the same environments as the native species. In 1997, the year of a strong El Niño/Southern Oscillation event with high rainfall and sea levels, the elevation distribution of species narrowed and densities of P. incurva and other exotic species decreased but densities of native and rare species did not change. The ‘regeneration niche’ of wetland plant communities includes the effects of multiple abiotic and biotic factors on both the spatial and temporal variations in plant establishment.     

Cultural conservatism and variability in the Acheulian sequence of Gesher Benot Ya‘aqov

The Acheulian Technocomplex exhibits two phenomena: variability and conservatism. Variability is expressed in the composition and frequencies of tool types, particularly in the varying frequencies of bifaces (handaxes and cleavers). Conservatism is expressed in the continuous presence of bifaces along an immense time trajectory. The site of Gesher Benot Ya‘aqov (GBY) offers a unique opportunity to study aspects of variability and conservatism as a result of its long cultural-stratigraphic sequence containing superimposed lithic assemblages. This study explores aspects of variability and conservatism within the Acheulian lithic assemblages of GBY, with emphasis placed on the bifacial tools. While variability has been studied through a comparison of typological frequencies in a series of assemblages from the site, evidence for conservatism was examined in the production modes expressed by the reduction sequence of the bifaces. We demonstrate that while pronounced typological variability is observed among the GBY assemblages, they were all manufactured by the same technology. The technology, size, and morphology of the bifaces throughout the entire stratigraphic sequence of GBY reflect the strong conservatism of their makers. We conclude that the biface frequency cannot be considered as a chrono/cultural marker that might otherwise allow us to distinguish between different phases within the Acheulian. The variability observed within the assemblages is explained as a result of different activities, tasks, and functions, which were carried out at specific localities along the shores of the paleo-Hula Lake in the early Middle Pleistocene.     

Upper extremity kinematic and kinetic adaptations during a fatiguing repetitive task

Repetitive low-force contractions are common in the workplace and yet can lead to muscle fatigue and work-related musculoskeletal disorders. The current study aimed to investigate potential motion adaptations during a simulated repetitive light assembly work task designed to fatigue the shoulder region, focusing on changes over time and age-related group differences. Ten younger and ten older participants performed four 20-min task sessions separated by short breaks. Mean and variability of joint angles and scapular elevation, joint net moments for the shoulder, elbow, and wrist were calculated from upper extremity kinematics recorded by a motion tracking system. Results showed that joint angle and joint torque decreased across sessions and across multiple joints and segments. Increased kinematic variability over time was observed in the shoulder joint; however, decreased kinematic variability over time was seen in the more distal part of the upper limb. The changes of motion adaptations were sensitive to the task-break schedule. The results suggested that kinematic and kinetic adaptations occurred to reduce the biomechanical loading on the fatigued shoulder region. In addition, the kinematic and kinetic responses at the elbow and wrist joints also changed, possibly to compensate for the increased variability caused by the shoulder joint while still maintaining task requirements. These motion strategies in responses to muscle fatigue were similar between two age groups although the older group showed more effort in adaptation than the younger in terms of magnitude and affected body parts.     

Bacterial ecology, antibiotics and selection for virulence

The evolution of antibiotic resistance in bacteria is well known. Here I describe possible mechanisms by which an increased rate of re-colonization of vertebrate guts by microbes caused by antibiotic use could lead to selection for increased virulence in currently mutualistic or benign microbes. The importance of understanding both the source and the frequency of colonization in such mutualisms is stressed and the possible importance of pseudo-vertical transmission in the evolution of these systems is discussed. A number of areas requiring experimental investigation are identified.     

Trilobites Calmoniidae de l'Ordovicien supérieur du Maroc et les origines de la Province Malvino-Cafre

A re-examination of the trilobite Baniaspis globosa Destombes (Phacopina) from the Ashgill of the Anti-Atlas (Morocco) shows that it has several derived characters which allow us to classify it in the family Calmoniidae. Calmoniids were characteristic members of the Malvino-Kaffric province during the Lower Devonian. Hence we regard the origins of this palaeogeographic province as located on the northern Gondwanan margin as early as Ashgill, or even Caradoc, times. We agree with those authors who have suggested that the trilobite associations present in the Anti-Atlas, the Montagne Noire (France) and Bohemia during the earlier Ordovician argue against the existence of a 'proto-Tethys' ocean.     

Comparative gastrointestinal morphology of the Kori bustard and secretary bird

Two secretary birds and three Kori bustards were studied to determine differences between their body size and gastrointestinal morphology. Body measurements were made on captive, live birds and gastrointestinal measurements on fresh postmortem specimens. For predator species, such as the Kori bustard and secretary bird, body size is a function of their ability to capture and destroy prey. While the secretary bird was clearly the taller of the two species, superior body weight, wing length, and therefore body size was noted for the Kori bustard. The size and length of the gastrointestinal tract varied between species. The secretary bird had the shorter, less complex digestive tract, with a foregut well adapted for consumption of large quantities of flesh. The large intestine was devoid of ceca. The gastrointestinal tract of the Kori bustard was markedly different from that of the secretary bird. The foregut was less complex and the large intestine possessed large, voluminous ceca.     

戴氏狼鳍鱼(Lycoptera davidi)的重新观察

本文主要对戴氏狼鳍鱼 (Lycoptera davidi) 骨骼系统的特征进行了补充和订正.在此基础上,对狼鳍鱼属 (Lycoptera) 的特征及有关狼鳍鱼种的分类问题作了初步探讨.     

Ritual production of environmental history among the Arawakan Wakuénai of Venezuela

This essay examines ritual and ceremonial activities among the Arawakspeaking Wakuénai of the Venezuelan Amazon as processes of constructing power relations in changing historical and ecological conditions. Ritual evocations of the vertical dimension of power relations between mythic ancestors and human descendants adapt local populations to conditions of relatively severe stress, such as epidemics and scarcity of fish in long wet seasons. Other rituals evoke the horizontal dimension of power relations between affinally-related groups as a way of expanding the local descent group in conditions of lowered stress. These two ways of exercising ritual power link human populations to specific natural habitats and provide flexibility needed to adjust to demographic and other historical changes. Through ritual performances, the Wakuénai transform the natural environment into a cultural landscape of socialized objects and, conversely, remember the history of political relations among peoples through spirit-naming of natural species, objects, places, and geographic landmarks.     

Studies on detection of Candida antigen in the sera of mice inoculated orally with Candida albicans

Summary The authors succeeded in establishing a murine model of systemic candidiasis being disseminated from the primary gastrointestinal lesions caused by oral inoculation of Candida albicans. Using this model, an attempt was made for detecting the Candida antigen by enzyme-linked immunosorbent assay using avidin-biotin (AB-ELISA) from the serum of infected mice.Gastrointestinal candidiasis was formed in all of the 20 mice treated with the drugs (antibiotics, antineoplastic agents, hydrocortisone, etc.) and inoculated orally with C. albicans. Fourteen of these mice suffered from submucosal candidiasis, and C. albicans was cultured from the visceral organs in 12 of them. The assay by AB-ELISA was able to detect 1.0 ng/ml Candida mannan in the mouse serum. The Candida antigen was detected in the sera of 11 of the 14 mice with submucosal candidiasis. However, the antigen could not be detected in the sera of the 6 mice with intramucosal candidiasis.The assay by AB-ELISA is more sensitive and specific for the diagnosis of systemic candidiasis than other serological assays.