Phylogenetic characterization of rabies virus isolates from Carnivora in Brazil

The incidence of canine rabies has been widely reported in Brazil, and new rabies virus (RV) variants, genetically similar to canine RV, have recently been isolated from foxes. In order to derive the epidemiological characteristics of Brazilian Carnivora RV, Brazilian RVs isolated from dogs, cats, and foxes were genetically analyzed. Brazilian Carnivora RV isolates were divided into 2 main lineages. The predominant lineage was found in dogs and cats, which included the Argentinean and Bolivian Carnivora RV isolates, and was extensively distributed throughout Brazil and surrounding countries. The other lineage consisted of three sublineages containing Brazilian dog and fox RV isolates, with the dog sublineages located on an internal branch of 2 fox sublineages, suggesting that RV transmission events might have occurred between foxes and dogs in the past. These results suggest that contact between dogs and wildlife has the potential to generate new rabies variants and that it is important to control RV infection cycles in both dogs and wildlife to prevent spread of rabies infection.     

The value of linking paleoecological and neoecological perspectives to understand spatially-explicit ecosystem resilience

Context

Predicting ecosystem resilience is a challenge, especially as climate change alters disturbance regimes and conditions for recovery. Recent research has highlighted the importance of spatially-explicit disturbance and resilience processes to long-term ecosystem dynamics. “Neoecological” approaches characterize resilience mechanisms at relatively fine spatio-temporal resolutions, but results are difficult to extrapolate across broad temporal scales or climatic ranges. Paleoecological methodologies can consider the effects of climates that differ from today. However, they are often limited to coarse-grained spatio-temporal resolutions.

Methods

In this synthesis, we describe implicit and explicit examples of studies that incorporate both neo- and paleoecological approaches. We propose ways to build on the strengths of both approaches in an explicit and proactive fashion.

Results

Linking the two approaches is a powerful way to surpass their respective limitations. Aligning spatial scales is critical: Paleoecological sampling design should incorporate knowledge of the spatial characteristics of the disturbance process, and neoecological studies benefit from a longer-term context to their conclusions. In some cases, modeling can incorporate non-spatial data from paleoecological records or emerging spatial paleo-data networks with mechanistic disturbance/recovery processes that operate at fine spatiotemporal scales.

Conclusions

Linking these two complementary approaches is a powerful way to build a complete understanding of ecosystem disturbance and resilience.

     

On the potential of documenting decadal-scale avifaunal change from before-and-after comparisons of museum and observational data across North America

Studies of biodiversity dynamics have been cast on either long(systematics)or short(ecology)time scales,leaving a gap in coverage for moderate time scales of de...     

Relationship of physical examination test of shoulder instability to arthroscopic findings in dogs

Objective— To determine the diagnostic validity of commonly used physical examination maneuvers for shoulder instability.
Study Design— Retrospective study.
Animals— Dogs (n=24) referred for shoulder arthroscopy.
Methods— Results of physical maneuvers and arthroscopic findings were recorded and sensitivity, specificity, positive likelihood ratios (LR+), and negative likelihood ratios (LR−) were calculated for each of 4 physical examination test findings for arthroscopic changes in the medial, lateral, cranial, or caudal compartments of the shoulder joint viewed in dorsal recumbency by lateral and craniomedial portals.
Results— Distribution of compartment changes was: medial (17 dogs), caudal (15), cranial (12), and lateral (5). The biceps test had a moderate effect (LR+=9) on post-test probability of cranial compartment changes and a small effect on post-test probability of lateral and caudal compartment changes (LR+=3 and 2.4, respectively). Hyperabduction had a minimal effect and mediolateral instability test had a small effect (LR+=1.64 and 2.68, respectively) on post-test probability of medial compartment changes. Craniocaudal instability test had little to no effect on post-test probability of changes in any compartment.
Conclusions— Physical examination tests evaluated were limited in their ability to predict the type of arthroscopic pathology in this study population.
Clinical Relevance — Clinicians should understand that a diagnostic test performs inconsistently based on prevalence of a condition in a given patient population. The use of likelihood ratios can assist clinicians in determining the probability of intraarticular changes from a group with a differing prevalence than the patient population presented.     

The importance of environment and life stage on interpretation of silky shark relative abundance indices for the equatorial Pacific Ocean

Recent large fluctuations in an index of relative abundance for the silky shark in the eastern Pacific Ocean have called into question its reliability as a population indicator for management. To investigate whether these fluctuations were driven by environmental forcing rather than true changes in abundance, a Pacific‐wide approach was taken. Data collected by observers aboard purse‐seine vessels fishing in the equatorial Pacific were used to compute standardized trends in relative abundance by region, and where possible, by shark size category as a proxy for life stage. These indices were compared to the Pacific Decadal Oscillation (PDO), an index of Pacific Ocean climate variability. Correlation between silky indices and the PDO was found to differ by region and size category. The highest correlations by shark size category were for small (<90 cm total length [TL]) and medium (90–150 cm TL) sharks from the western region of the equatorial eastern Pacific (EP) and from the equatorial western Pacific. This correlation disappeared in the inshore EP. Throughout, correlations with the PDO were generally lower for large silky sharks (>150 cm TL). These results are suggestive of changes in the small and medium silky indices being driven by movement of juvenile silky sharks across the Pacific as the eastern edge of the Indo‐Pacific Warm Pool shifts location with ENSO events. Lower correlation of the PDO with large shark indices may indicate that those indices were less influenced by environmental forcing and therefore potentially less biased with respect to monitoring population trends.     

Quantifying Microbial Methane Oxidation Efficiencies in Two Experimental Landfill Biocovers Using Stable Isotopes

Stable isotope analyses were performed on gas samples collected within two instrumented biocovers, with the goal of evaluating CH₄ oxidation efficiencies (f ₀). In each of the biocovers, gas probes were installed at four locations and at several depths. One of the biocovers was fed with biogas directly from the waste mass, whereas the other was fed through a gas distribution system that allowed monitoring of biogas fluxes. While the f ₀ values obtained at a depth of 0.1 m were low (between 0.0% and 25.2%) for profiles with poor aeration, they were high for profiles with better aeration, reaching 89.7%. Several interrelated factors affecting aeration seem to be influencing f ₀, including the degree of water saturation, the magnitude of the biogas flux and the temperature within the substrate. Low f ₀ values do not mean necessarily that little CH₄ was oxidized. In fact, in certain cases where the CH₄ loading was high, the absolute amount of CH₄ oxidized was quite high and comparable to the rate of CH₄ oxidation for cases with low CH₄ loading and high f ₀. For the experimental biocover for which the CH₄ loading was known, the oxidation efficiency obtained using stable isotopes (f ₀?=?55.67% for samples taken inside flux chambers) was compared to the value obtained by mass balance (f ₀?=?70.0%). Several factors can explain this discrepancy, including the high sensitivity of f ₀ to slight changes in the isotopic fractionation factor for bacterial oxidation, α _ox, uncertainties related to mass flow metre readings and to the static chamber method.     

Natural hazards and genetic diversity in rice

Rice crop diversity hasdecreased dramatically in the recent past.Understanding the causes that underlie theevident genetic erosion is critical for thefood security of subsistence rice farmers andbiodiversity. Our study shows that farmers inthe northeastern Philippines had a markedreduction in rice diversity from 1996 to 1998.The ultimate causes were a drought resultingfrom the El Niño phenomenon in 1997 andflooding due to two successive typhoons in1998. The proximate causes, however, includedlocal water control factors, limitations in thehousehold and village-level seedinfrastructure, farm location in relation tothe goods and services necessary to obtainseeds, policies and programs of the Departmentof Agriculture, and the characteristics of therice varieties themselves. The implications ofour study are that genetic erosion is notalways the result of purposeful acts by farmersnor is it necessarily gradual. Improvingon-farm seed technology will stabilize the seedproduction, distribution, and use system andthereby enhance household food security.Ultimately, rice diversity will be improvedonly if diversity is a safe and viable optionfor farmers. Therefore, public policy thatsupports farmers who maintain a diverse set ofcultivars is critical for any on-farmconservation strategy.     

Individual growth variation and its relationship with survival in juvenile Pacific oysters, Crassostrea gigas (Thunberg)

In order to study individual growth variability and its relationship with survival in juvenile Crassostrea gigas, parental oysters were sampled at four sites located along the French Atlantic coast and bred under controlled hatchery conditions. Four groups of larvae were obtained by crossing five males and five females from each of the four sites, and a fifth group by crossing these 20 males and 20 females together in a pool. Larvae were reared under conditions allowing the maintenance of a maximum variability of size and gave five experimental groups. Oysters were individually monitored for growth and survival from 3 to 10 months after fertilization. The individual growth performances were relatively stable over time and no noticeable compensation for growth occurred. Early growth rate was a very good predictor of size later in life: 66% of variation in the live weight at 10 months could be explained by variation in the initial growth rate calculated between 3 and 4 months. A significant group effect was observed on survival and on growth rate. Mortality mostly occurred between 3 and 5 months and appeared to affect the slow-growing animals more. However, two groups can be distinguished among those which died during the experimental period, one which showed a decrease in weight and the other whose growth was similar to surviving oysters. These results are discussed in the light of usual oyster farming practices and selective breeding. This revised version was published online in August 2006 with corrections to the Cover Date.