6,204 research outputs found
Gender, Social Networks, and Voting Behavior
This paper examines how interpersonal social networks help explain the voting behavior of men and women. We argue that the gender gap in voting is influenced by the partisan and gender composition of networks, rather than just the latter. Building on this foundation, we explain how gendering in network construction and impact helps create a cleavage between men and women even under conditions that are often close to random mixing. Analysis of the 2000 American National Election Study shows the voting gap is related to men excluding women from political networks, men being less exposed to females who support Democrats, and men being more strongly influence by women who support Republicans. The principal conclusion of the paper is that the role of social networks in explaining gendered voting is a function of combined partisan and gender segregation, principally by men
The Full-sky Astrometric Mapping Explorer -- Astrometry for the New Millennium
FAME is designed to perform an all-sky, astrometric survey with unprecedented
accuracy. It will create a rigid astrometric catalog of 4x10^7 stars with 5 <
m_V < 15. For bright stars, 5 < m_V < 9, FAME will determine positions and
parallaxes accurate to < 50 microarcseconds, with proper motion errors < 50
microarcseconds/year. For fainter stars, 9 < m_V < 15, FAME will determine
positions and parallaxes accurate to < 500 microarcseconds, with proper motion
errors < 500 microarcseconds/year. It will also collect photometric data on
these 4 x 10^7 stars in four Sloan DSS colors.Comment: 6 pages, 4 figures, to appear in "Working on the Fringe
Neural responses to facial and vocal expressions of fear and disgust
Neuropsychological studies report more impaired responses to facial expressions of fear than disgust in people with amygdala lesions, and vice versa in people with Huntington's disease. Experiments using functional magnetic resonance imaging (fMRI) have confirmed the role of the amygdala in the response to fearful faces and have implicated the anterior insula in the response to facial expressions of disgust. We used fMRI to extend these studies to the perception of fear and disgust from both facial and vocal expressions. Consistent with neuropsychological findings, both types of fearful stimuli activated the amygdala. Facial expressions of disgust activated the anterior insula and the caudate-putamen; vocal expressions of disgust did not significantly activate either of these regions. All four types of stimuli activated the superior temporal gyrus. Our findings therefore (i) support the differential localization of the neural substrates of fear and disgust; (ii) confirm the involvement of the amygdala in the emotion of fear, whether evoked by facial or vocal expressions; (iii) confirm the involvement of the anterior insula and the striatum in reactions to facial expressions of disgust; and (iv) suggest a possible general role for the perception of emotional expressions for the superior temporal gyrus
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Millimeter-Scale Contact Printing of Aqueous Solutions Using a Stamp Made Out of Paper and Tape
This communication describes a simple method for printing aqueous solutions with millimeter-scale patterns on a variety of substrates using an easily fabricated, paper-based microfluidic device (a paper-based “stamp”) as a contact printing device. The device is made from inexpensive materials, and it is easily assembled by hand; this method is thus accessible to a wide range of laboratories and budgets. A single device was used to print over 2500 spots in less than three minutes at a density of 16 spots per square centimeter. This method provides a new tool to pattern biochemicals—reagents, antigens, proteins, and DNA—on planar substrates. The accuracy of the volume of fluid delivered in simple paper-to-paper printing is low, and although the pattern transfer is rapid, it is better suited for qualitative than accurate, quantitative work. By patterning the paper to which the transfer occurs using wax printing or an equivalent technique, accuracy increases substantially.Chemistry and Chemical Biolog
Measuring Binding of Protein to Gel-Bound Ligands Using Magnetic Levitation
This paper describes the use of magnetic levitation (MagLev) to measure the association of proteins and ligands. The method starts with diamagnetic gel beads that are functionalized covalently with small molecules (putative ligands). Binding of protein to the ligands within the bead causes a change in the density of the bead. When these beads are suspended in a paramagnetic aqueous buffer and placed between the poles of two NbFeB magnets with like poles facing, the changes in the density of the bead on binding of protein result in changes in the levitation height of the bead that can be used to quantify the amount of protein bound. This paper uses a reaction–diffusion model to examine the physical principles that determine the values of rate and equilibrium constants measured by this system, using the well-defined model system of carbonic anhydrase and aryl sulfonamides. By tuning the experimental protocol, the method is capable of quantifying either the concentration of protein in a solution, or the binding affinities of a protein to several resin-bound small molecules simultaneously. Since this method requires no electricity and only a single piece of inexpensive equipment, it may find use in situations where portability and low cost are important, such as in bioanalysis in resource-limited settings, point-of-care diagnosis, veterinary medicine, and plant pathology. It still has several practical disadvantages. Most notably, the method requires relatively long assay times and cannot be applied to large proteins (>70 kDa), including antibodies. The design and synthesis of beads with improved characteristics (e.g., larger pore size) has the potential to resolve these problems.Chemistry and Chemical Biolog
Identification of flavin-containing monooxygenase 5 (FMO5) as a regulator of glucose homeostasis and a potential sensor of gut bacteria
We have previously identified flavin-containing monooxygenase 5 (FMO5) as a regulator of metabolic aging. The aim of the present study was to investigate the role of FMO5 in glucose homeostasis and the impact of diet and gut flora on the phenotype of mice in which the Fmo5 gene has been disrupted (Fmo5−/− mice). In comparison with wild-type (WT) counterparts, Fmo5−/− mice are resistant to age-related changes in glucose homeostasis and maintain the higher glucose tolerance and insulin sensitivity characteristic of young animals. When fed a high-fat diet, they are protected against weight gain and reduction of insulin sensitivity. The phenotype of Fmo5−/− mice is independent of diet and the gut microbiome and is determined solely by the host genotype. Fmo5−/− mice have metabolic characteristics similar to those of germ-free mice, indicating that FMO5 plays a role in sensing or responding to gut bacteria. In WT mice, FMO5 is present in the mucosal epithelium of the gastrointestinal tract where it is induced in response to a high-fat diet. In comparison with WT mice, Fmo5−/− mice have fewer colonic goblet cells, and they differ in the production of the colonic hormone resistin-like molecule β. Fmo5−/− mice have lower concentrations of tumor necrosis factor α in plasma and of complement component 3 in epididymal white adipose tissue, indicative of improved inflammatory tone. Our results implicate FMO5 as a regulator of body weight and of glucose disposal and insulin sensitivity and, thus, identify FMO5 as a potential novel therapeutic target for obesity and insulin resistance
Preserving the palaeoenvironmental record in Drylands: Bioturbation and its significance for luminescence-derived chronologies
Luminescence (OSL) dating has revolutionised the understanding of Late Pleistocene dryland activity. However,
one of the key assumptions for this sort of palaeoenvironmental work is that sedimentary sequences have been
preserved intact, enabling their use as proxy indicators of past changes. This relies on stabilisation or burial
soon after deposition and a mechanism to prevent any subsequent re-mobilisation. As well as a dating
technique OSL, especially at the single grain level, can be used to gain an insight into post-depositional
processes that may distort or invalidate the palaeoenvironmental record of geological sediment sequences.
This paper explores the possible impact of bioturbation (the movement of sediment by flora and fauna) on
luminescence derived chronologies from Quaternary sedimentary deposits in Texas and Florida (USA) which
have both independent radiocarbon chronologies and archaeological evidence. These sites clearly illustrate the
ability of bioturbation to rejuvenate ancient weathered sandy bedrock and/or to alter depositional stratigraphies
through the processes of exhumation and sub-surface mixing of sediment. The use of multiple OSL replicate
measurements is advocated as a strategy for checking for bioturbated sediment. Where significant OSL
heterogeneity is found, caution should be taken with the derived OSL ages and further measurements at the
single grain level are recommended. Observations from the linear dunes of the Kalahari show them to have no
bedding structure and to have OSL heterogeneity similar to that shown from the bioturbated Texan and Florida
sites. The Kalahari linear dunes could have therefore undergone hitherto undetected post-depositional sediment
disturbance which would have implications for the established OSL chronology for the region
The Canada-UK Deep Submillimetre Survey: The Survey of the 14-hour field
We have used SCUBA to survey an area of 50 square arcmin, detecting 19
sources down to a 3sigma sensitivity limit of 3.5 mJy at 850 microns. We have
used Monte-Carlo simulations to assess the effect of source confusion and noise
on the SCUBA fluxes and positions, finding that the fluxes of sources in the
SCUBA surveys are significantly biased upwards and that the fraction of the 850
micron background that has been resolved by SCUBA has been overestimated. The
radio/submillmetre flux ratios imply that the dust in these galaxies is being
heated by young stars rather than AGN. We have used simple evolution models
based on our parallel SCUBA survey of the local universe to address the major
questions about the SCUBA sources: (1) what fraction of the star formation at
high redshift is hidden by dust? (2) Does the submillimetre luminosity density
reach a maximum at some redshift? (3) If the SCUBA sources are
proto-ellipticals, when exactly did ellipticals form? However, we show that the
observations are not yet good enough for definitive answers to these questions.
There are, for example, acceptable models in which 10 times as much
high-redshift star formation is hidden by dust as is seen at optical
wavelengths, but also acceptable ones in which the amount of hidden star
formation is less than that seen optically. There are acceptable models in
which very little star formation occurred before a redshift of three (as might
be expected in models of hierarchical galaxy formation), but also ones in which
30% of the stars have formed by this redshift. The key to answering these
questions are measurements of the dust temperatures and redshifts of the SCUBA
sources.Comment: 41 pages (latex), 17 postscript figures, to appear in the November
issue of the Astronomical Journa
A Century of Cosmology
In the century since Einstein's anno mirabilis of 1905, our concept of the
Universe has expanded from Kapteyn's flattened disk of stars only 10 kpc across
to an observed horizon about 30 Gpc across that is only a tiny fraction of an
immensely large inflated bubble. The expansion of our knowledge about the
Universe, both in the types of data and the sheer quantity of data, has been
just as dramatic. This talk will summarize this century of progress and our
current understanding of the cosmos.Comment: Talk presented at the "Relativistic Astrophysics and Cosmology -
Einstein's Legacy" meeting in Munich, Nov 2005. Proceedings will be published
in the Springer-Verlag "ESO Astrophysics Symposia" series. 10 pages Latex
with 2 figure
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