217 research outputs found

    Unhousing the Urban Poor: The Reagan Legacy

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    The Reagan era was characterized by the popularity of individual level explanations and market based solutions for a range of social problems, including homelessness. We argue that such an approach was inadequate and may, in fact, have toorsened the housing situation. We claim that homelessness is fundamentally a housing problem linked to two key trends of the 1980s: the increasing rate of poverty and the declining supply\u27f low-income housing. Market approaches to housing policy have resulted in housing policies by default: gentrification, condo conversion and displacement as well as tax policies that explicitly favor the nonpoor. Those policies gehred towards the poor, vouchers and subsidies, were inadequate responses to increasing need. In sum, the Reagan years witnessed dramatic declines in the supply of low-cost housing, substantial increases in the poverty rate, and drastic shifts in federal policy towards housing the poor

    ‘They think we are delaying their outputs’. The challenges of interdisciplinary research: understanding power dynamics between social and biophysical scientists in international crop breeding teams

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    Public sector crop improvement for development programmes aims to produce varieties tailored to the needs of smallholder farmers and their environments. Understanding how social heterogeneity, including gender, drives trait preferences is essential to ensure that crop improvement objectives meet farmers’ and stakeholder demands. This requires an interdisciplinary approach, integrating social science knowledge with crop breeding. Although the necessity of interdisciplinary research is recognised and promoted, it is impeded by a multitude of challenges including ontological and epistemological differences, institutional and global hierarchies, disciplinary power relations and struggles for scientific authority. The Agricultural Research for Development (AR4D) sector is marked by entrenched power differentials, including dominance of the biophysical sciences, a historical emphasis on technical solutions which ignores social contexts, and the underrepresentation of women scientists and farmers themselves. Nevertheless, there is limited theoretically informed analysis of power dynamics within AR4D settings. Drawing on qualitative, ethnographic observations of the Feed the Future Innovation Lab for Crop Improvement (ILCI), this article seeks to understand how power affects interdisciplinary research processes. Critical ethnography and power theory is used to analyse power within international crop breeding collaborations and the implications for inclusive knowledge production and research impact. The Powercube is used to examine how visible, hidden and invisible forms of power manifest within local, national, and international relationships across closed, invited and claimed spaces. Our findings suggest that these intersecting power dimensions, which include disciplinary, gendered, institutional and global hierarchies, constrain the contributions that individual researchers can make – particularly social scientists – thereby hindering disciplinary integration. The ILCI case study reveals the complex multi-dimensional dynamics that emerge within agricultural research teams and highlights structural limitations constraining efforts to build socially inclusive and gender-responsive crop improvement programmes. The article contributes to a small but growing literature studying the social construction of agricultural science, and provides insights that can enable interdisciplinary research strategies to more effectively meet the needs of farmers and other stakeholders

    Origin and trends in NH4+ observed in the coma of 67P

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    The European Space Agency/Rosetta mission escorted comet 67P/Churyumov–Gerasimenko and witnessed the evolution of its coma from low activity (∌2.5–3.8 au) to rich ion-neutral chemistry (∌1.2–2.0 au). We present an analysis of the ion composition in the coma, focusing on the presence of protonated high proton affinity (HPA) species, in particular NH4+ ⁠. This ion is produced through the protonation of NH3 and is an indicator of the level of ion-neutral chemistry in the coma. We aim to assess the importance of this process compared with other NH4+ sources, such as the dissociation of ammonium salts embedded in dust grains. The analysis of NH4+ has been possible thanks to the high mass resolution of the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis/Double Focusing Mass Spectrometer (ROSINA/DFMS). In this work, we examine the NH4+ data set alongside data from the Rosetta Plasma Consortium instruments, and against outputs from our in-house ionospheric model. We show that increased comet outgassing around perihelion yields more detections of NH4+ and other protonated HPA species, which results from more complex ion-neutral chemistry occurring in the coma. We also reveal a link between the low magnetic field strength associated with the diamagnetic cavity and higher NH4+ counts. This suggests that transport inside and outside the diamagnetic cavity is very different, which is consistent with 3D hybrid simulations of the coma: non-radial plasma dynamics outside the diamagnetic cavity is an important factor affecting the ion composition

    Multicomplementary operators via finite Fourier transform

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    A complete set of d+1 mutually unbiased bases exists in a Hilbert spaces of dimension d, whenever d is a power of a prime. We discuss a simple construction of d+1 disjoint classes (each one having d-1 commuting operators) such that the corresponding eigenstates form sets of unbiased bases. Such a construction works properly for prime dimension. We investigate an alternative construction in which the real numbers that label the classes are replaced by a finite field having d elements. One of these classes is diagonal, and can be mapped to cyclic operators by means of the finite Fourier transform, which allows one to understand complementarity in a similar way as for the position-momentum pair in standard quantum mechanics. The relevant examples of two and three qubits and two qutrits are discussed in detail.Comment: 15 pages, no figure

    Far-ultraviolet aurora identified at comet 67P/ Churyumov-Gerasimenko

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    Having a nucleus darker than charcoal, comets are usually detected from Earth through the emissions from their coma. The coma is an envelope of gas that forms through the sublimation of ices from the nucleus as the comet gets closer to the Sun. In the far-ultraviolet portion of the spectrum, observations of comae have revealed the presence of atomic hydrogen and oxygen emissions. When observed over large spatial scales as seen from Earth, such emissions are dominated by resonance fluorescence pumped by solar radiation. Here, we analyse atomic emissions acquired close to the cometary nucleus by the Rosetta spacecraft and reveal their auroral nature. To identify their origin, we undertake a quantitative multi-instrument analysis of these emissions by combining coincident neutral gas, electron and far-ultraviolet observations. We establish that the atomic emissions detected from Rosetta around comet 67P/Churyumov-Gerasimenko at large heliocentric distances result from the dissociative excitation of cometary molecules by accelerated solar-wind electrons (and not by electrons produced from photo-ionization of cometary molecules). Like the discrete aurorae at Earth and Mars, this cometary aurora is driven by the interaction of the solar wind with the local environment. We also highlight how the oxygen line O I at wavelength 1,356 Å could be used as a tracer of solar-wind electron variability

    Heterochromatic sequences in a Drosophila whole-genome shotgun assembly

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    BACKGROUND: Most eukaryotic genomes include a substantial repeat-rich fraction termed heterochromatin, which is concentrated in centric and telomeric regions. The repetitive nature of heterochromatic sequence makes it difficult to assemble and analyze. To better understand the heterochromatic component of the Drosophila melanogaster genome, we characterized and annotated portions of a whole-genome shotgun sequence assembly. RESULTS: WGS3, an improved whole-genome shotgun assembly, includes 20.7 Mb of draft-quality sequence not represented in the Release 3 sequence spanning the euchromatin. We annotated this sequence using the methods employed in the re-annotation of the Release 3 euchromatic sequence. This analysis predicted 297 protein-coding genes and six non-protein-coding genes, including known heterochromatic genes, and regions of similarity to known transposable elements. Bacterial artificial chromosome (BAC)-based fluorescence in situ hybridization analysis was used to correlate the genomic sequence with the cytogenetic map in order to refine the genomic definition of the centric heterochromatin; on the basis of our cytological definition, the annotated Release 3 euchromatic sequence extends into the centric heterochromatin on each chromosome arm. CONCLUSIONS: Whole-genome shotgun assembly produced a reliable draft-quality sequence of a significant part of the Drosophila heterochromatin. Annotation of this sequence defined the intron-exon structures of 30 known protein-coding genes and 267 protein-coding gene models. The cytogenetic mapping suggests that an additional 150 predicted genes are located in heterochromatin at the base of the Release 3 euchromatic sequence. Our analysis suggests strategies for improving the sequence and annotation of the heterochromatic portions of the Drosophila and other complex genomes

    Relationship of perfluorooctanoic acid exposure to pregnancy outcome based on birth records in the mid-Ohio Valley.

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    BACKGROUND: Perfluorooctanoic acid (PFOA) is a potential cause of adverse pregnancy outcomes, but previous studies have been limited by low exposures and small study size. OBJECTIVES: Using birth certificate information, we examined the relation between estimated PFOA exposure and birth outcomes in an area of West Virginia and Ohio whose drinking water was contaminated by a chemical plant. METHODS: Births in the study area from 1990 through 2004 were examined to generate case groups of stillbirth (n = 106), pregnancy-induced hypertension (n = 224), preterm birth (n = 3,613), term low birth weight (n = 918), term small-for-gestational-age (SGA) (n = 353), and a continuous measure of birth weight among a sample of term births (n = 4,534). A 10% sample of term births ≄ 2,500 g were selected as a source of controls (n = 3,616). Historical estimates of serum PFOA were derived from a previously developed fate and transport model. In a second study, we examined 4,547 area births linked to a survey with residential history data. RESULTS: In the analysis based only on birth records, we found no consistent evidence of an association between estimated PFOA exposure and stillbirth, pregnancy-induced hypertension, preterm birth, or indices of fetal growth. In the analysis of birth records linked to the survey, PFOA was unrelated to pregnancy-induced hypertension or preterm birth but showed some suggestion of an association with early preterm birth. Measures of growth restriction showed weak and inconsistent associations with PFOA. CONCLUSIONS: Based on the analysis using the health survey, these results provide little support for an effect of PFOA exposure on most pregnancy outcomes, except for early preterm birth and possibly fetal growth restriction

    The heterogeneous coma of comet 67P/Churyumov-Gerasimenko as seen by ROSINA: H <inf>2</inf> O, CO <inf>2</inf>, and CO from September 2014 to February 2016

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    Context. The ESA Rosetta mission has been investigating the environment of comet 67P/Churyumov-Gerasimenko (67P) since August 2014. Among the experiments on board the spacecraft, the ROSINA experiment (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis) includes two mass spectrometers to analyse the composition of neutrals and ions and a COmet Pressure Sensor (COPS) to monitor the density and velocity of neutrals in the coma. Aims. We study heterogeneities in the coma during three periods starting in October 2014 (summer in the northern hemisphere) and ending in February 2016 (end of winter in the northern hemisphere). We provide a detailed description of the main volatiles dynamics (H2O, CO2, CO) and their abundance ratios. Methods. We analysed and compared the data of the Reflectron-Type Time-Of-Flight (RTOF) mass spectrometer with data from both the Double Focusing Mass Spectrometer (DFMS) and COPS during the comet escort phase. This comparison has demonstrated that the observations performed with each ROSINA sensor are indeed consistent. Furthermore, we used a Direct Simulation Monte Carlo (DSMC) model to compare modelled densitites with in situ detections. Results. Our analysis shows how the active regions of the main volatiles evolve with the seasons with a variability mostly driven by the illumination conditions; this is the case except for an unexpected dichotomy suggesting the presence of a dust layer containing water deposited in the northern hemisphere during previous perihelions hiding the presence of CO2. The influence of various parameters is investigated in detail: distance to the comet, heliocentric distance, longitude and latitude of sub-satellite point, local time, and phase angle

    Acute inhalation of hypertonic saline does not improve mucociliary clearance in all children with cystic fibrosis

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    <p>Abstract</p> <p>Background</p> <p>Little is known of how mucociliary clearance (MCC) in children with cystic fibrosis (CF) and normal pulmonary function compares with healthy adults, or how an acute inhalation of 7% hypertonic saline (HS) aerosol affects MCC in these same children.</p> <p>Methods</p> <p>We compared MCC in 12 children with CF and normal pulmonary function after an acute inhalation of 0.12% saline (placebo), or HS, admixed with the radioisotope <sup>99 m</sup>technetium sulfur colloid in a double-blind, randomized, cross-over study. Mucociliary clearance on the placebo day in the children was also compared to MCC in 10 healthy, non-CF adults. Mucociliary clearance was quantified over a 90 min period, using gamma scintigraphy, and is reported as MCC at 60 min (MCC60) and 90 min (MCC90).</p> <p>Results</p> <p>Median [interquartile range] MCC60 and MCC90 in the children on the placebo visit were 15.4 [12.4-24.5]% and 19.3 [17.3-27.8%]%, respectively, which were similar to the adults with 17.8 [6.4-28.7]% and 29.6 [16.1-43.5]%, respectively. There was no significant improvement in MCC60 (2.2 [-6.2-11.8]%) or MCC90 (2.3 [-1.2-10.5]%) with HS, compared to placebo. In addition, 5/12 and 4/12 of the children showed a decrease in MCC60 and MCC90, respectively, after inhalation of HS. A <it>post hoc </it>subgroup analysis of the change in MCC90 after HS showed a significantly greater improvement in MCC in children with lower placebo MCC90 compared to those with higher placebo MCC90 (p = 0.045).</p> <p>Conclusions</p> <p>These data suggest that percent MCC varies significantly between children with CF lung disease and normal pulmonary functions, with some children demonstrating MCC values within the normal range and others showing MCC values that are below normal values. In addition, although MCC did not improve in all children after inhalation of HS, improvement did occur in children with relatively low MCC values after placebo. This finding suggests that acute inhalation of hypertonic saline may benefit a subset of children with low MCC values.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov: <a href="http://www.clinicaltrials.gov/ct2/show/NCT01293084">NCT01293084</a></p

    Polymorphisms in CYP1B1, GSTM1, GSTT1 and GSTP1, and susceptibility to breast cancer

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    Polymorphisms in the cytochrome P450 1B1 (CYP1B1) and glutathione S-transferase (GST) drug metabolic enzymes, which are responsible for metabolic activation/detoxification of estrogen and environmental carcinogens, were analyzed for their association with breast cancer risk in 541 cases and 635 controls from a North Carolina population. Each polymorphism, altering the catalytic function of their respective enzymes, was analyzed in Caucasian and African-American women. As reported in previous studies, individual polymorphisms did not significantly impact breast cancer risk in either Caucasian or African-American women. However, African-American women exhibited a trend towards a protective effect when they had at least one CYP1B1 119S allele (OR=0.53; 95% CI=0.20–1.40) and increased risk for those women harboring at least one CYP1B1 432V allele (OR=5.52; 95% CI=0.50–61.37). Stratified analyses demonstrated significant interactions in younger (age ≀60) Caucasian women with the CYP1B1 119SS genotype (OR=3.09; 95% CI=1.22–7.84) and younger African-American women with the GSTT1 null genotype (OR=4.07; 95% CI=1.12–14.80). A notable trend was also found in Caucasian women with a history of smoking and at least one valine allele at GSTP1 114 (OR=2.12; 95% CI=1.02–4.41). In Caucasian women, the combined GSTP1 105IV/VV and CYP1B1 119AA genotypes resulted in a near 2-fold increase in risk (OR=1.96; 95% CI=1.04–3.72) and the three way combination of GSTP1 105IV/VV, CYP1B1 119AS/SS and GSTT1 null genotypes resulted in an almost 4-fold increase in risk (OR=3.97; 95% CI=1.27–12.40). These results suggest the importance of estrogen/carcinogen metabolic enzymes in the etiology of breast cancer, especially in women before the age of 60, as well as preventative measures such as smoking cessation
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