The live bird market system and low-pathogenic avian influenza prevention in southern California

Although live bird markets (LBMs) have been associated with outbreaks of avian influenza (AI), there are some LBM systems where AI outbreaks are extremely rare events. The California LBMs have not had any detected avian influenza viruses (AIVs) since December 2005. Responses to a detailed questionnaire on the practices and characteristics of the participants in the California low-pathogenic (LP) AI control program have been described to characterize possible reasons for the lack of AI outbreaks in LBMs. Compliance with an LPAI control program that contains active surveillance, prevention, and rapid response measures by those involved in the LBM system, rendering services to dispose of carcasses, no wholesalers, and few third-party bird deliveries was associated with the lack of LPAIV circulating in the Southern California LBM system.     

Soil Phosphorus Variability: Scale-dependence in an Urbanizing Agricultural Landscape

We examine the hypothesis that human activity changes patterns of variance in soil P (Bray-1) concentrations across several spatial scales. We measured soil P concentrations and variability for each of four different land uses at three distinct levels of analysis. Land uses were remnant prairie, lawns, corn fields of cash grain farms, and corn fields of dairies in Dane County, Wisconsin (USA). For each land use type, levels of analysis were sites (an agricultural field, residential lawn or prairie, ranging in size from 100 m² to approximately 20 ha), 10-m plots within a site, and points within the 10-m diameter plot. The rank of mean soil P concentrations was cash grain > dairy > lawn > prairie. For all land use types, most of the variance was accounted for by site-to-site variation. Among-site variance was higher for human-dominated sites (0.55, 0.15, 0.14 [log (mg/kg)]² for cash grain, dairy, and lawn sites, respectively) than it was for prairies (0.07 [log (mg/kg)]²). However, prairies had the highest among-plot variation (0.04 [log (mg/kg)]²) compared to other sites (0.01, 0.002, and 0.01 [log (mg/kg)]² for cash grain, dairy, and lawn sites, respectively). The results indicate that in this watershed, human activity has increased the mean soil P and variance of soil P, and shifted the scale of variance to larger spatial extents. Human impacts on landscape pattern extend to soil properties that affect nutrient flow and eutrophication of surface waters. Because soil P turns over slowly, the legacy of altered soil P patterns may affect freshwaters for centuries.     

Estimating the Risk of Exceeding Thresholds in Environmental Systems

Environmental regulations often rely on limits or thresholds to indicate an acceptable pollutant load. Estimates of the Risk of Exceeding such Thresholds (RET) are often based on a single model deemed to be the best for the particular pollutant or particular case. However, if many models make different predictions but explain the data almost equally well, predictions based on a single model may omit important information contained in other models that fit almost as well as the “best” single model. More accurate assessments of RET may result if multiple models are considered. We compared performance of the single best model relative to that of an ensemble of models estimated by bagging (Bootstrap AGGregatING) using the example of soil P concentrations and the risk of exceeding environmental limits of soil P concentrations in the watershed of Lake Mendota, Wisconsin, USA. Bagging yielded significantly better predictions of the risk of exceeding a threshold level of soil P (99.6% accuracy versus 74% for single-model prediction at a 20 mg kg^?1 threshold). Use of multiple model techniques can improve estimates of RET over a range of realistic thresholds in other management situations where thresholds are important including eutrophication, desertification, fisheries, and many types of pollution control.     

Flexible system for the diagnosis of schizophrenia: report from the WHO International Pilot Study of Schizophrenia

Behavioral data on a large patient group were collected by investigators from nine countries in the International Pilot Study of Schizophrenia, sponsored by the World Health Organization. The data on half the group were analyzed to derive a system of 12 signs and symptoms for the identification of schizophrenia, as this disorder is diagnosed in many centers throughout the world. The findings were replicated with the other half of the patient group. The criteria constitute an operational method for identifying patients who would be commonly considered schizophrenic in many centers.     

Ecological forecasts: an emerging imperative

Planning and decision-making can be improved by access to reliable forecasts of ecosystem state, ecosystem services, and natural capital. Availability of new data sets, together with progress in computation and statistics, will increase our ability to forecast ecosystem change. An agenda that would lead toward a capacity to produce, evaluate, and communicate forecasts of critical ecosystem services requires a process that engages scientists and decision-makers. Interdisciplinary linkages are necessary because of the climate and societal controls on ecosystems, the feedbacks involving social change, and the decision-making relevance of forecasts.     

The first mesozoic ants

Two worker ants preserved in amber of Upper Cretaceous age have been found in New Jersey. They are the first undisputed remains of social insects of Mesozoic age, extending the existence of social life in insects back to approximately 100 million years. They are also the earliest known fossils that can be assigned with certainty to aculeate Hymenoptera. The species, Sphecomyrma freyi, is considered to represent a new subfamily (Sphecomyrminae), more primitive than any previously known ant group. It forms a near-perfect link between certain nonsocial tiphiid wasps and the most primitive myrmecioid ants.     

Circular polarization in star- formation regions: implications for biomolecular homochirality

Strong infrared circular polarization resulting from dust scattering in reflection nebulae in the Orion OMC-1 star-formation region has been observed. Circular polarization at shorter wavelengths might have been important in inducing chiral asymmetry in interstellar organic molecules that could be subsequently delivered to the early Earth by comets, interplanetary dust particles, or meteors. This could account for the excess of L-amino acids found in the Murchison meteorite and could explain the origin of the homochirality of biological molecules.     

Structure and molecular mechanism of a nucleobase-cation-symport-1 family transporter

The nucleobase-cation-symport-1 (NCS1) transporters are essential components of salvage pathways for nucleobases and related metabolites. Here, we report the 2.85-angstrom resolution structure of the NCS1 benzyl-hydantoin transporter, Mhp1, from Microbacterium liquefaciens. Mhp1 contains 12 transmembrane helices, 10 of which are arranged in two inverted repeats of five helices. The structures of the outward-facing open and substrate-bound occluded conformations were solved, showing how the outward-facing cavity closes upon binding of substrate. Comparisons with the leucine transporter LeuT(Aa) and the galactose transporter vSGLT reveal that the outward- and inward-facing cavities are symmetrically arranged on opposite sides of the membrane. The reciprocal opening and closing of these cavities is synchronized by the inverted repeat helices 3 and 8, providing the structural basis of the alternating access model for membrane transport.     

Antiphosphotyrosine recovery of phospholipase C activity after EGF treatment of A-431 cells

A tenfold increase in phospholipase C activity specific for phosphatidylinositol 4,5-bisphosphate (PIP2) was immunopurified from extracts of A-431 epidermoid carcinoma cells stimulated with epidermal growth factor. This finding suggests a biochemical link between growth factor-stimulated tyrosine kinase activity and PIP2 hydrolysis.