Using Residential History and Groundwater Modeling to Examine Drinking Water Exposure and Breast Cancer

BACKGROUND. Spatial analyses of case-control data have suggested a possible link between breast cancer and groundwater plumes in upper Cape Cod, Massachusetts. OBJECTIVE. We integrated residential histories, public water distribution systems, and groundwater modeling within geographic information systems (GIS) to examine the association between exposure to drinking water that has been contaminated by wastewater effluent and breast cancer. METHODS. Exposure was assessed from 1947 to 1993 for 638 breast cancer cases who were diagnosed from 1983 to 1993 and 842 controls; we took into account residential mobility and drinking water source. To estimate the historical impact of effluent on drinking water wells, we modified a modular three-dimensional finite-difference groundwater model (MODFLOW) from the U.S. Geological Survey. The analyses included latency and exposure duration. RESULTS. Wastewater effluent impacted the drinking water wells of study participants as early as 1966. For > 0-5 years of exposure (versus no exposure), associations were generally null. Adjusted odds ratios (AORs) for > 10 years of exposure were slightly increased, assuming latency periods of 0 or 10 years [AOR = 1.3; 95% confidence interval (CI), 0.9-1.9 and AOR = 1.6; 95% CI, 0.8-3.2, respectively]. Statistically significant associations were estimated for ever-exposed versus never-exposed women when a 20-year latency period was assumed (AOR = 1.9; 95% CI, 1.0-3.4). A sensitivity analysis that classified exposures assuming lower well-pumping rates showed similar results. CONCLUSION. We investigated the hypothesis generated by earlier spatial analyses that exposure to drinking water contaminated by wastewater effluent may be associated with breast cancer. Using a detailed exposure assessment, we found an association with breast cancer that increased with longer latency and greater exposure duration.National Cancer Institute (5R03CA119703-02); National Institute of Environmental Health Sciences (5P42 ES007381

Impacts of Unionization on Employment, Product Quality and Productivity: Regression Discontinuity Evidence From Nursing Homes

This paper studies the effects of nursing home unionization on numerous labor, establishment, and consumer outcomes using a regression discontinuity design. We find negative effects of unionization on staffing levels and no decline in care quality, suggesting positive labor productivity effects. Some evidence suggests that nursing homes in less competitive local product markets and those with lower union density at the time of election experienced stronger union employment effects. Unionization appears to raise wages for a given worker while also shifting the composition of the workforce away from higher-earning workers. By combining credible identification of union effects, a comprehensive set of outcomes over time with measures of market-level characteristics, this study generates some of the best evidence available on many controversial questions in the economics of unions. Furthermore, it generates evidence from the service sector, which has grown in importance and where evidence has been thin.

Using genotyping-by-sequencing to understand Musa diversity

Poster presented at Plant and Animal Genome, PAG XXII. San Diego (USA), 11-15 Jan 201

Polymerisable surfactants for polymethacrylates using catalytic chain transfer polymerisation (CCTP) combined with sulfur free-RAFT in emulsion polymerisation

Statistical copolymers of methacrylic acid and methyl methacrylate were synthesised via free radical catalytic chain transfer polymerisation (CCTP) in emulsion to form a hydrophilic emulsifier/surfactant. The vinyl-terminated oligomers were in turn utilised as chain transfer agents, with no further purification, for the formation of diblock copolymers with butyl and methyl methacrylate which constitutes the emulsifier via sulfur-free reversible addition–fragmentation chain transfer polymerisation (SF-RAFT). In turn these polymers were solubilized with various concentrations of ammonium hydroxide and utilised in the surfactant-free emulsion polymerization of butyl methacrylate using persulfate initiators, which also stabilized the polymer particles with observed no coagulation, with solid contents as high as 40%

Results of Universal Prenatal Screening for Hepatitis C Infection in a Remote American Indian Primary Care Population

BACKGROUND: Although chronic liver disease remains a major area of health disparity for American Indian (AI) people, the epidemiology of hepatitis C virus (HCV) infection among AI people is poorly documented. Because of suspected high local prevalence, two remote AI clinics in the Northern Plains implemented universal prenatal HCV screening in 2005. When this screening program reported an unexpectedly high prenatal anti-HCV (anti-HCV antibody) positivity rate, we conducted a case-control study to determine risks for infection and opportunities for community intervention. MAIN FINDINGS: The clinics screened a total of 205 pregnant women (median age, 22 years). Of these 205 women, a total of 13 (6.3%; 95% confidence interval, 3.4–10.6) had anti-HCV confirmed. Of the anti-HCV-positive women, 10 (76.9%) were aged 15–24 years. We included 10 cases and 40 anti-HCV-negative prenatal controls in a case-control study. On multivariate analysis, only injection-drug use (IDU) remained associated with HCV seropositivity. CONCLUSIONS: Universal prenatal screening revealed a high prevalence of anti-HCV at these remote AI clinics. This population has not been previously described at being at elevated risk for HCV infection. In order to reduce health disparities, young, rural AI populations seeking prenatal care need to be included in interventions to reduce HCV transmission

Intraparticulate speciation analysis of soft nanoparticulate metal complexes:The impact of electric condensation on the binding of Cd2+/Pb2+/Cu2+ by humic acids

In aqueous dispersions of soft, charged nanoparticles, the physicochemical conditions prevailing within the particle body generally differ substantially from those in the bulk medium. Accordingly it is necessary to define intrinsic descriptors that appropriately reflect the chemical speciation inside the particle's microenvironment. Herein the speciation of divalent metal ions within the body of negatively charged soft nanoparticulate complexants is elaborated for the example case of humic acid association with Cd(ii), Pb(ii) and Cu(ii). The electrostatic effects are described by a two-state model that accounts for counterion condensation in the intraparticulate double layer shell at the particle/medium interface and Donnan partitioning within the bulk of the particle body. Inner-sphere complex formation is defined by an intrinsic binding constant expressed in terms of local reactant concentrations as controlled by the pertinent electrostatic conditions. For the high particle charge density case (Debye length smaller than charged site separation), three distinct intraparticulate metal species are identified, namely free hydrated ions, electrostatically condensed ions, and inner-sphere metal-humic complexes. For all metal ions studied, the electrostatic contribution to the association of the metal ion with the oppositely charged particle is found to account for a substantial fraction of the total metal bound.</p

Sound Localization of World and Head-Centered Space in Ferrets

The location of sounds can be described in multiple coordinate systems that are defined relative to ourselves, or the world around us. Evidence from neural recordings in animals point towards the existence of both head-centered and world-centered representations of sound location in the brain; however, it is unclear whether such neural representations have perceptual correlates in the sound localization abilities of non-human listeners. Here, we establish novel behavioral tests to determine the coordinate systems in which ferrets can localize sounds. We found that ferrets could learn to discriminate between sound locations that were fixed in either world-centered or head-centered space, across wide variations in sound location in the alternative coordinate system. Using probe sounds to assess broader generalization of spatial hearing, we demonstrated that in both head and world-centered tasks, animals used continuous maps of auditory space to guide behavior. Single trial responses of individual animals were sufficiently informative that we could then model sound localization using speaker position in specific coordinate systems and accurately predict ferrets’ actions in held-out data. Our results indicate that an animal model in which neurons are known to be tuned to sound location in egocentric and allocentric reference frames can also localize sounds in multiple head and world-centered spaces

Usporedna procjena oksidacije amalgama kronopotenciometrijom i voltametrijom

The characteristic features of scanned deposition potential curves constructed from stripping chronopotentiometry (SSCP) and various modes of stripping voltammetry (SSV) are critically evaluated. The strengths and weaknesses of each method for identification of metal ion speciation features and susceptibility to typical interferences are described for conventional (HMDE) and microelectrodes, i.e. irreversibility in the electron transfer reaction, multi-metal resolution, intermetallic compound formation, homogeneous kinetics, induced metal adsorption, and requirement for excess ligand to avoid saturation at the electrode surface during reoxidation. The most advantageous stripping modes are those in which practically complete depletion of the accumulated metal is achieved during the reoxidation step, i.e. SCP with low stripping current and DC-SV with slow potential scan rate. Under these conditions there is a straightforward quantitative relationship between the amount of metal accumulated and the analytical signal. The slow rate of oxidation with these modes renders them practically immune to induced metal adsorption; they have a lower requirement for excess ligand in the sample solution and greater resistance to both irreversibility in the electrochemical oxidation and to interference from intermetallic compounds. Even in the case of nonreversible electrode processes, or for systems limited by complex formation/dissociation kinetics, depletive scanned deposition potential stripping curves allow complexation parameters to be determined from the shift in half-wave deposition potential, analogous to the DeFord-Hume approach for conventional voltammetry. SSCP has greater sensitivity, and provides greater resolution in multi-metal systems than does depletive DC-SSV, while SSV provides useful complementary information in some cases.Kritički su procijenjena karakteristična svojstva pseudopolarograma konstruiranih korištenjem dvaju metoda oksidacije amalgama: kronopotenciometrije i voltametrije. Pseudopolarogram je prikaz ovisnosti najvećeg intenziteta odziva oksidacije amalgama o potencijalu redukcije metalnih iona. Opisane su prednosti i mane obaju metoda pri određivanju raspodjele metalnih kompleksa i njihova podložnost tipičnim smetnjama. Analizirani su odzivi na visećoj živinoj kapi i na mikroelektrodama. Razmatrane su sljedeće pojave: reverzibilnost i brzina prijenosa elektrona, razdvajanje odziva većeg broja metala u živi, stvaranje intermetalnih spojeva u živi, utjecaji kemijskih reakcija koje prethode redukciji metalnih iona ili slijede oksidaciju amalgama, inducirana adsorpcija metalnih iona na površinu živine elektrode i minimalni višak slobodnog liganda potreban da se tijekom oksidacije amalgama svi metalni ioni uz površinu elektrode odmah kompleksiraju. Najbolja metoda oksidacije jest ona kojom se postiže potpuna oksidacija svih metalnih atoma akumuliranih u živi. Taj uvjet zadovoljavaju kronopotenciometrija sa slabom strujom i voltametrija sa sporom promjenom potencijala. Pod tim uvjetima postoji kvantitativna funkcionalna veza intenziteta odziva i količine akumuliranih metalnih atoma. Metode spore oksidacije su imune na induciranu adsorpciju, trebaju manji višak slobodnog liganda, manje ovise o brzini izmjene elektrona i manje im smetaju intermetalni spojevi. Ovim metodama mogu se odrediti konstante stabilnosti metalnih kompleksa i u slučajevima kinetički kontroliranih elektrodnih reakcija i sporih reakcija kompleksiranja ili disocijacije kompleksa. Pokazano je da je kronopotenciometrija osjetljivija od voltametrije i da se njenim korištenjem postiže bolja rezolucija odziva većeg broja metala, ali se voltametrijom mogu dobiti dodatne informacije o istraživanom sustavu