3,232 research outputs found
Oceanographic Profiling and Spectroradiometer Observations from the MOCE-1 Cruise: 28 August to 8 October 1992
This report contains the frrst observations made for the Modis Optical Characterization Experiment (MOCE). Data presented here were obtained on the R/V DeSteiguer between 28 August and 8 October along the central California coast and in Monterey Bay. Three types of data are reported here: high spectral resolution radiometry at three depths for seven stations; salinity, temperature, fluorescence and beam attenuation profiles at the same stations; and total suspended matter and suspended organic carbon and nitrogen. [PDF contans 164 pages
Gender-Specific Protection from Microvessel Rarefaction in Female Hypertensive Rats
Epidemiologic studies reveal that women have a significantly lower age-adjusted morbidity and mortality from cardiovascular disease than men, suggesting that gender is a cardiovascular disease risk factor. The mechanism of the “gender protection” is unknown. In this study, we investigated the microvascular remodeling in reduced renal mass plus a high salt (4.0% NaCl) diet model of hypertension (RRM + HS). We hypothesized that women would be protected from the increase in blood pressure and from the microvascular rarefaction associated with RRM + HS hypertension. Studies were designed to determine whether female rats were less susceptible to changes in microvessel density during RRM + HS. Microvessel density was measured in male and female low salt (0.4% LS) sham-operated controls (Sham + LS) and after 3 days or 4 weeks of RRM + HS hypertension. The microcirculation of hind limb (medial and lateral gastrocnemius, plantaris, soleus) muscles was visualized using rhodamine-labeled Griffonia simplicifolia I lectin. Tissue sections were examined by videomicroscopy and microvessel density was determined by quantitative stereology. As shown previously, mean arterial pressure increased to 160 ± 8 mm Hg and microvessel density decreased (\u3e30% decrease in all beds) in male RRM + HS. In contrast, mean arterial pressure of female RRM + HS rats was modestly increased from 101 ± 2 to 118 ± 4 mm Hg. Despite previous results showing a reduction in microvessel density of both normotensive and hypertensive male rats on a high salt diet, microvessel density of female RRM + HS rats was not reduced at either time. These results suggest that gender protection in the RRM rat extends beyond an attenuation of the increase in pressure to an immunity from microvascular rarefaction
Reef Structure Alternatives for Restoration of Oyster (Crassostrea virginica) Populations in New Hampshire
Eastern oyster (Crassostrea virginica) populations in New Hampshire have experienced severe declines since the 1990s, and restoration of oyster populations has been a major goal for New Hampshire management agencies. The most widely used technique in recent years in New Hampshire has been spat seeding which involves setting larvae from disease-resistant and/or fast-growth broodstock onto cultch material in large shore-based tanks, then distributing the spat attached to cultch onto the bottom to initiate reef restoration. This approach has the dual potential of providing direct population enhancement as well as introduction to the local gene pool of disease-resistance and/or fast-growth potential. Although spat seeding has been shown to be an effective technique much remains to be learned about the overall restoration process, particularly specific design criteria, the most effective combinations of methods, and long-term viability of restored bottom areas.
The present project was designed in part based on results of earlier experimental work (mainly the use of spat seeding) to address the general management question: How should reefs be structurally enhanced (if at all) to enhance oyster populations and improve spat set
Persons, Person Stages, Adaptive Preferences, and Historical Wrongs
Let’s say that an act requires Person-Affecting Justification if and only if some alternative would have been better for someone. So, Lucifer breaking Xavier’s back requires Person-Affecting Justification because the alternative would have been better for Xavier. But the story continues: While Lucifer evades justice, Xavier moves on and founds a school for gifted children. Xavier’s deepest values become identified with the school and its community. When authorities catch Lucifer, he claims no Person-Affecting Justification is needed: because the attack set Xavier on his life’s path, it’s no longer true that the alternative would have been better by the standard of what Xavier now values most. An unappealingly paternalistic way to hold Lucifer to account is to discount Xavier’s preferences as merely adaptive. Instead, I propose understanding the persons of Person-Affecting Justification to be not persons but person stages. This allows us to hold Lucifer to account without having to discount Xavier’s actual preferences, and has interesting implications for compensatory justice, including making sense of reparations for historical wrongs
The Structure of Nuclear Star Clusters in Nearby Late-type Spiral Galaxies from Hubble Space Telescope Wide Field Camera 3 Imaging
We obtained Hubble Space Telescope/Wide Field Camera 3 imaging of a sample of
ten of the nearest and brightest nuclear clusters residing in late-type spiral
galaxies, in seven bands that span the near-ultraviolet to the near-infrared.
Structural properties of the clusters were measured by fitting two-dimensional
surface brightness profiles to the images using GALFIT. The clusters exhibit a
wide range of structural properties. For six of the ten clusters in our sample,
we find changes in the effective radius with wavelength, suggesting radially
varying stellar populations. In four of the objects, the effective radius
increases with wavelength, indicating the presence of a younger population
which is more concentrated than the bulk of the stars in the cluster. However,
we find a general decrease in effective radius with wavelength in two of the
objects in our sample, which may indicate extended, circumnuclear star
formation. We also find a general trend of increasing roundness of the clusters
at longer wavelengths, as well as a correlation between the axis ratios of the
NCs and their host galaxies. These observations indicate that blue disks
aligned with the host galaxy plane are a common feature of nuclear clusters in
late-type galaxies, but are difficult to detect in galaxies that are close to
face-on. In color-color diagrams spanning the near-UV through the near-IR, most
of the clusters lie far from single-burst evolutionary tracks, showing evidence
for multi-age populations. Most of the clusters have integrated colors
consistent with a mix of an old population (> 1 Gyr) and a young population
(~100-300 Myr). The wide wavelength coverage of our data provides a sensitivity
to populations with a mix of ages that would not be possible to achieve with
imaging in optical bands only.Comment: Corrected a typo in author name and affiliation for MC and corrected
a typo in the conclusio
Elliptical-core two mode fiber sensors and devices incorporating photoinduced refractive index gratings
Results of experiments performed using germanium-doped, elliptical core, two-mode optical fibers whose sensitivity to strain was spatially varied through the use of chirped, refractive-index gratings permanently induced into the core using Argon-ion laser light are presented. This type of distributed sensor falls into the class of eighted-fiber sensors which, through a variety of means, weight the strain sensitivity of a fiber according to a specified spatial profile. We describe results of a weighted-fiber vibration mode filter which successfully enhances the particular vibration mode whose spatial profile corresponds to the profile of the grating chirp. We report on the high temperature survivability of such grating-based sensors and discuss the possibility of multiplexing more than one sensor within a single fiber
Algal food and fuel coproduction can mitigate greenhouse gas emissions while improving land and water-use efficiency
The goals of ensuring energy, water, food, and climate security can often conflict.Microalgae (algae) are
being pursued as a feedstockfor both food and fuels—primarily due to algae’s high areal yield and ability
to grow on non-arable land, thus avoiding common bioenergy-food tradeoffs. However, algal cultivation
requires significant energy inputs that may limit potential emission reductions.We examine the tradeoffs
associated with producing fuel andfood from algae at the energy–food–water–climate nexus.We use the
GCAM integrated assessment model to demonstrate that algalfood production can promote reductions
in land-use change emissions through the offset of conventional agriculture. However,fuel production,
either via co-production of algal food and fuel or complete biomass conversion to fuel, is necessary to
ensure long-term emission reductions, due to the high energy costs of cultivation. Cultivation of salt–
water algae for food products may lead to substantial freshwater savings; but, nutrients for algae
cultivation will need to be sourced from waste streams to ensure sustainability. By reducing the land
demand of food production, while simultaneously enhancingfood and energy security, algae can further
enable the development of terrestrial bioenergy technologies including those utilizing carbon capture and
storage. Our results demonstrate that large-scale algae research and commercialization efforts should
focus on developing both food and energy products to achieve environmental goals.https://iopscience.iop.org/article/10.1088/1748-9326/11/11/114006/metaPublished versio
Huntingtin Fragments and SOD1 Mutants Form Soluble Oligomers in the Cell
Diffusion coefficients of huntingtin (Htt) fragments and SOD1 mutants expressed in cells were measured using fluorescence correlation spectroscopy. The diffusion mobilities of both non-pathological Htt fragments (25 polyQs) and pathological Htt fragments (103 polyQs) were much slower than expected for monomers suggesting that they oligomerize. The mobility of these fragments was unaffected by duration of expression or by over-expression of Hsp70 and Hsp40. However in cells with HttQ103 inclusions, diffusion measurements showed that the residual cytosolic HttQ103 was monomeric. These results suggest that both non-pathological and pathological Htt fragments form soluble oligomers in the cytosol with the properties of the oligomers determining whether they cause pathology. SOD1 with point mutations (A4V, G37R, and G85R) also had slower diffusional mobility than the wild-type protein whose mobility was consistent with that of a dimer. However, the decrease in mobility of the different SOD1 mutantsdid not correlate with their known pathology. Therefore, while soluble oligomers always seem to be present under conditions where cell pathology occurs, the presence of the oligomers, in itself, does not determine the extent of neuropathology
Using Megamaser Disks to Probe Black Hole Accretion
We examine the alignment between H_2O megamaser disks on sub-pc scales with
circumnuclear disks and bars on <500 pc scales observed with HST/WFC3. The HST
imaging reveals young stars, indicating the presence of gas. The megamaser
disks are not well aligned with the circumnuclear bars or disks as traced by
stars in the HST images. We speculate on the implications of the observed
misalignments for fueling supermassive black holes in gas-rich spiral galaxies.
In contrast, we find a strong preference for the rotation axes of the megamaser
disks to align with radio continuum jets observed on >50 pc scales, in those
galaxies for which radio continuum detections are available. Sub-arcsecond
observations of molecular gas with ALMA will enable a more complete
understanding of the interplay between circumnuclear structures.Comment: Error in Figure 4 corrected, references added. 7 pages, 4 figures, to
be published in the Astrophysical Journa
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