Schools Respond to Risk Management Programs for Asbestos, Lead in Drinking Water and Radon

Based on a study of the three EPA-initiated, public school risk management programs noted in the title, the authors find that state agency involvement is an important factor in the success of such programs. They also find, e.g., that school districts are justifiably reluctant to comply with tentative program

A Comparison Of Memory Span And Absolute Judgement In Three Adult Populations

The present study employed 60 adult subjects (38 White females, 3 Black females, 18 White males, and 1 Black male). The absolute judgement task and the memory span task have important empirical similarities; namely, 7 + - 2, while each is purported as measures of different abilities

Spin-resonance modes of the spin-gap magnet TlCuCl_3

Three kinds of magnetic resonance signals were detected in crystals of the spin-gap magnet TlCuCl_3. First, we have observed the microwave absorption due to the excitation of the transitions between the singlet ground state and the excited triplet states. This mode has the linear frequency-field dependence corresponding to the previously known value of the zero-field spin-gap of 156 GHz and to the closing of spin-gap at the magnetic field H_c of about 50 kOe. Second, the thermally activated resonance absorption due to the transitions between the spin sublevels of the triplet excitations was found. These sublevels are split by the crystal field and external magnetic field. Finally, we have observed antiferromagnetic resonance absorption in the field-induced antiferromagnetic phase above the critical field H_c. This resonance frequency is strongly anisotropic with respect to the direction of the magnetic field.Comment: v.2: typo correction (one of the field directions was misprinted in the v.1

Hamiltonian submanifolds of regular polytopes

We investigate polyhedral $2k$-manifolds as subcomplexes of the boundary complex of a regular polytope. We call such a subcomplex {\it $k$-Hamiltonian} if it contains the full $k$-skeleton of the polytope. Since the case of the cube is well known and since the case of a simplex was also previously studied (these are so-called {\it super-neighborly triangulations}) we focus on the case of the cross polytope and the sporadic regular 4-polytopes. By our results the existence of 1-Hamiltonian surfaces is now decided for all regular polytopes. Furthermore we investigate 2-Hamiltonian 4-manifolds in the $d$-dimensional cross polytope. These are the "regular cases" satisfying equality in Sparla's inequality. In particular, we present a new example with 16 vertices which is highly symmetric with an automorphism group of order 128. Topologically it is homeomorphic to a connected sum of 7 copies of $S^2 \times S^2$. By this example all regular cases of $n$ vertices with $n < 20$ or, equivalently, all cases of regular $d$-polytopes with $d\leq 9$ are now decided.Comment: 26 pages, 4 figure

Denitrification and total nitrate uptake in streams of a tropical landscape

Author Posting. © Ecological Society of America, 2010. This article is posted here by permission of Ecological Society of America for personal use, not for redistribution. The definitive version was published in Ecological Applications 20 (2010): 2104-2115, doi:10.1890/09-1110.1.Rapid increases in nitrogen (N) loading are occurring in many tropical watersheds, but the fate of N in tropical streams is not well documented. Rates of nitrate uptake and denitrification were measured in nine tropical low-order streams with contrasting land use as part of the Lotic Intersite Nitrogen eXperiment II (LINX II) in Puerto Rico using short term (24-hour) additions of K15NO3 and NaBr. Background nitrate concentrations ranged from 105 to 997 μg N/L, and stream nitrate uptake lengths were long, varying from 315 to 8480 m (median of 1200 m). Other indices of nitrate uptake (mass transfer coefficient, Vf [cm/s], and whole-stream nitrate uptake rate, U [μg N·m−2·s−1]) were low in comparison to other regions and were related to chemical, biological, and physical parameters. Denitrification rates were highly variable (0–133 μg N·m−2·min−1; median = 15 μg N·m−2·min−1), were dominated by the end product N2 (rather than N2O), and were best predicted by whole-stream respiration rates and stream NO3 concentration. Denitrification accounted for 1–97% of nitrate uptake with five of nine streams having 35% or more of nitrate uptake via denitrification, showing that denitrification is a substantial sink for nitrate in tropical streams. Whole-stream nitrate uptake and denitrification in our study streams closely followed first-order uptake kinetics, indicating that NO3 uptake is limited by delivery of substrate (NO3) to the organisms involved in uptake or denitrification. In the context of whole-catchment nitrogen budgets, our finding that in-stream denitrification results in lower proportional production of N2O than terrestrial denitrification suggests that small streams can be viewed as the preferred site of denitrification in a watershed in order to minimize greenhouse gas N2O emissions. Conservation of small streams is thus critical in tropical ecosystem management.This research was part of the Lotic Intersite Nitrogen eXperiment II (LINX II) funded by the National Science Foundation (DEB-0111410). Additional support was provided by the National Science Foundation to the Institute of Terrestrial Ecology at the University of Puerto Rico and the International Institute of Tropical Forestry (DEB-0218039 and DEB-0620919) through the Luquillo Long Term Ecological Research (LUQ LTER) program

Heterogeneous Occupancy and Density Estimates of the Pathogenic Fungus Batrachochytrium dendrobatidis in Waters of North America

Biodiversity losses are occurring worldwide due to a combination of stressors. For example, by one estimate, 40% of amphibian species are vulnerable to extinction, and disease is one threat to amphibian populations. The emerging infectious disease chytridiomycosis, caused by the aquatic fungus Batrachochytrium dendrobatidis (Bd), is a contributor to amphibian declines worldwide. Bd research has focused on the dynamics of the pathogen in its amphibian hosts, with little emphasis on investigating the dynamics of free-living Bd. Therefore, we investigated patterns of Bd occupancy and density in amphibian habitats using occupancy models, powerful tools for estimating site occupancy and detection probability. Occupancy models have been used to investigate diseases where the focus was on pathogen occurrence in the host. We applied occupancy models to investigate free-living Bd in North American surface waters to determine Bd seasonality, relationships between Bd site occupancy and habitat attributes, and probability of detection from water samples as a function of the number of samples, sample volume, and water quality. We also report on the temporal patterns of Bd density from a 4-year case study of a Bd-positive wetland. We provide evidence that Bd occurs in the environment year-round. Bd exhibited temporal and spatial heterogeneity in density, but did not exhibit seasonality in occupancy. Bd was detected in all months, typically at less than 100 zoospores L⁻¹. The highest density observed was ~3 million zoospores L⁻¹. We detected Bd in 47% of sites sampled, but estimated that Bd occupied 61% of sites, highlighting the importance of accounting for imperfect detection. When Bd was present, there was a 95% chance of detecting it with four samples of 600 ml of water or five samples of 60 mL. Our findings provide important baseline information to advance the study of Bd disease ecology, and advance our understanding of amphibian exposure to free-living Bd in aquatic habitats over time

The Crystal Ball Data Acquisition System

The data acquisition system for the Crystal Ball project at SLAC is described. A PDP-11/t55 using RSX-11M connected to the SLAC Triplex is the basis of the system. A "physics pipeline" allows physicists to write their own equipment-monitoring or physics tasks which require event sampling. As well, an interactive analysis package (MULTI) is in the pipeline. Histogram collection and display on the PDP are implemented using the Triplex histogramming package. Various interactive event displays are also implemented

Addition of insulin glargine or NPH insulin to metformin monotherapy in poorly controlled type 2 diabetic patients decreases IGF-I bioactivity similarly

Aims/hypothesis The aim of this study was to compare IGFI bioactivity 36 weeks after the addition of insulin glargine (A21Gly,B31Arg,B32Arg human insulin) or NPH insulin to metformin therapy in type 2 diabetic patients who had poor glucose control under metformin monotherapy. Methods In the Lantus plus Metformin (LANMET) study, 110 poorly controlled insulin-naive type 2 diabetic patients were randomised to receive metformin with either insulin glargine (G+MET) or NPH insulin (NPH+MET). In the present study, IGF-I bioactivity was measured, retrospectively, in 104 out of the 110 initially included LANMET participants before and after 36 weeks of insulin therapy. IGF-I bioactivity was measured using an IGF-I kinase receptor activation assay. Results After 36 weeks of insulin therapy, insulin doses were comparable between the G+MET (68±5.7 U/day) and NPH+MET (71±6.2 U/day) groups (p=0.68). Before insulin therapy, circulating IGF-I bioactivity was similar between the G+MET (134±9 pmol/l) and NPH+MET (135 ±10 pmol/l) groups (p=0.83). After 36 weeks, IGF-I bioactivity had decreased significantly (p=0.001) and did not differ between the G+MET (116±9 pmol/l) and NPH+MET (117± 10 pmol/l) groups (p=0.91). At baseline and after insulin therapy, total IGF-I concentrations were comparable in both groups (baseline: G+MET 13.3±1.0 vs NPH+MET 13.3± 1.0 nmol/l, p=0.97; and 36 weeks: 13.4±1.0 vs 13.1± 0.9 nmol/l, p=0.71). Total IGF-I concentration did not change during insulin therapy (13.3±0.7 vs 13.3±0.7 nmol/l, baseline vs 36 weeks, p=0.86). Conclusions/interpretation Addition of insulin glargine or NPH insulin to metformin monotherapy in poorly controlled type 2 diabetic patients decreases serum IGF-I bioactivity in a similar manner