3,905 research outputs found
Tertiary Treatment of Wastewater Using Oxidation Ponds
The purpose of the project was to determine the value of using lagoons as a supplemental process for treating the effluent from an activated sludge wastewater treatment plant.
Only tentative conclusions can be suggested since the project was not carried to completion. It appears that lagoons will have only minimal effect on the amounts of total nitrogen and phosphate in the plant effluent, although conversion of a portion of the ammonia to nitrate can be expected. However, the concentration of ammonia was never lower than that required by EPA guidelines. Some reduction of soluble BOD appears to occur, perhaps through conversion to new cell material. Suspended solids concentrations can be expected to increase during periods of algae growth.
The numbers of both fecal and total coliform bacteria decreased substantially during the detention period provided by the lagoon system. Although not confirmed, it was concluded that the most probable cause for the decrease was the intensity and duration of sunlight.
The lagoon served very effectively as a buffer between the treatment plant and the receiving stream, providing a considerable measure of protection to the stream even during those periods during which the plant was by-passing a portion of the inflow
Decoherence Bounds on Quantum Computation with Trapped Ions
Using simple physical arguments we investigate the capabilities of a quantum
computer based on cold trapped ions. From the limitations imposed on such a
device by spontaneous decay, laser phase coherence, ion heating and other
sources of error, we derive a bound between the number of laser interactions
and the number of ions that may be used. The largest number which may be
factored using a variety of species of ion is determined.Comment: 5 pages in RevTex, 2 figures, the paper is also avalaible at
http://qso.lanl.gov/qc
Islet‐specific CD8+ T cells gain effector function in the gut lymphoid tissues via bystander activation not molecular mimicry
Type 1 diabetes (T1D) is caused by aberrant activation of autoreactive T cells specific for the islet beta cells. How islet‐specific T cells evade tolerance to become effector T cells is unknown, but it is believed that an altered gut microbiota plays a role. Possible mechanisms include bystander activation of autoreactive T cells in the gut or “molecular mimicry” from cross‐reactivity between gut microbiota‐derived peptides and islet‐derived epitopes. To investigate these mechanisms, we use two islet‐specific CD8+ T cell clones and the non‐obese diabetic mouse model of type 1 diabetes. Both insulin‐specific G9C8 cells and IGRP‐specific 8.3 cells underwent early activation and proliferation in the pancreatic draining lymph nodes but not in the Peyer's patches or mesenteric lymph nodes. Mutation of the endogenous epitope for G9C8 cells abolished their CD69 upregulation and proliferation, ruling out G9C8 cell activation by a gut microbiota derived peptide and molecular mimicry. However, previously activated islet‐specific effector memory cells but not naïve cells migrated into the Peyer's patches where they increased their cytotoxic function. Oral delivery of butyrate, a microbiota derived anti‐inflammatory metabolite, reduced IGRP‐specific cytotoxic function. Thus, while initial activation of islet‐specific CD8+ T cells occurred in the pancreatic lymph nodes, activated cells trafficked through the gut lymphoid tissues where they gained additional effector function via non‐specific bystander activation influenced by the gut microbiota
Interlaboratory Evaluation of in Vitro Cytotoxicity and Inflammatory Responses to Engineered Nanomaterials: The NIEHS Nano GO Consortium
Background: Differences in interlaboratory research protocols contribute to the conflicting data in the literature regarding engineered nanomaterial (ENM) bioactivity.
Objectives: Grantees of a National Institute of Health Sciences (NIEHS)-funded consortium program performed two phases of in vitro testing with selected ENMs in an effort to identify and minimize sources of variability.
Methods: Consortium program participants (CPPs) conducted ENM bioactivity evaluations on zinc oxide (ZnO), three forms of titanium dioxide (TiO2), and three forms of multiwalled carbon nanotubes (MWCNTs). In addition, CPPs performed bioassays using three mammalian cell lines (BEAS-2B, RLE-6TN, and THP-1) selected in order to cover two different species (rat and human), two different lung epithelial cells (alveolar type II and bronchial epithelial cells), and two different cell types (epithelial cells and macrophages). CPPs also measured cytotoxicity in all cell types while measuring inflammasome activation [interleukin-1β (IL-1β) release] using only THP-1 cells.
Results: The overall in vitro toxicity profiles of ENM were as follows: ZnO was cytotoxic to all cell types at ≥ 50 μg/mL, but did not induce IL-1β. TiO2 was not cytotoxic except for the nanobelt form, which was cytotoxic and induced significant IL-1β production in THP-1 cells. MWCNTs did not produce cytotoxicity, but stimulated lower levels of IL-1β production in THP-1 cells, with the original MWCNT producing the most IL-1β.
Conclusions: The results provide justification for the inclusion of mechanism-linked bioactivity assays along with traditional cytotoxicity assays for in vitro screening. In addition, the results suggest that conducting studies with multiple relevant cell types to avoid false-negative outcomes is critical for accurate evaluation of ENM bioactivity
The Relation Between the Surface Brightness and the Diameter for Galactic Supernova Remnants
In this work, we have constructed a relation between the surface brightness
() and diameter (D) of Galactic C- and S-type supernova remnants
(SNRs). In order to calibrate the -D dependence, we have carefully
examined some intrinsic (e.g. explosion energy) and extrinsic (e.g. density of
the ambient medium) properties of the remnants and, taking into account also
the distance values given in the literature, we have adopted distances for some
of the SNRs which have relatively more reliable distance values. These
calibrator SNRs are all C- and S-type SNRs, i.e. F-type SNRs (and S-type SNR
Cas A which has an exceptionally high surface brightness) are excluded. The
Sigma-D relation has 2 slopes with a turning point at D=36.5 pc: (at 1
GHz)=8.4 D
WmHzster (for
WmHzster and D36.5 pc) and (at 1
GHz)=2.7 10 D
WmHzster (for
WmHzster and D36.5 pc). We discussed the theoretical
basis for the -D dependence and particularly the reasons for the change
in slope of the relation were stated. Added to this, we have shown the
dependence between the radio luminosity and the diameter which seems to have a
slope close to zero up to about D=36.5 pc. We have also adopted distance and
diameter values for all of the observed Galactic SNRs by examining all the
available distance values presented in the literature together with the
distances found from our -D relation.Comment: 45 pages, 2 figures, accepted for publication in Astronomical and
Astrophysical Transaction
Mooring design using wave-state estimate from the Southern Ocean
Author Posting. © American Meteorological Society, 2011. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Atmospheric and Oceanic Technology 28 (2011): 1351–1360, doi:10.1175/JTECH-D-10-05033.1.The Southern Ocean Flux Station was deployed near 47°S, 140°E. The extreme wind and wave conditions at this location require appropriate mooring design, which includes dynamic fatigue analysis and static analysis. An accurate estimate of the wave conditions was essential. A motion reference unit was deployed in a nearby test mooring for 6 months. The motion data provided estimates of significant wave height that agreed well with the Australian Bureau of Meteorology wave model, increasing confidence in the model performance in the Southern Ocean. The results of the dynamic fatigue analysis using three input wave datasets and implications for the mooring design are described. The design analysis predicts the fatigue life for critical mooring components and guided the final selection of links and chain shackles. The three input wave climatologies do not differ greatly, and this is reflected in minimal changes to mooring components for each of the fatigue analyses.Many years of logistic support
for these deployments have been provided by the
Australian Marine National Facility and the Australian
Antarctic Sciences program (Award 1156). IMOS is
funded through the Federal Government’s National
Collaborative Research Infrastructure Strategy and the
Super Science Initiative
First narrow-band search for continuous gravitational waves from known pulsars in advanced detector data
Spinning neutron stars asymmetric with respect to their rotation axis are potential sources of
continuous gravitational waves for ground-based interferometric detectors. In the case of known pulsars a
fully coherent search, based on matched filtering, which uses the position and rotational parameters
obtained from electromagnetic observations, can be carried out. Matched filtering maximizes the signalto-
noise (SNR) ratio, but a large sensitivity loss is expected in case of even a very small mismatch
between the assumed and the true signal parameters. For this reason, narrow-band analysis methods have
been developed, allowing a fully coherent search for gravitational waves from known pulsars over a
fraction of a hertz and several spin-down values. In this paper we describe a narrow-band search of
11 pulsars using data from Advanced LIGO’s first observing run. Although we have found several initial
outliers, further studies show no significant evidence for the presence of a gravitational wave signal.
Finally, we have placed upper limits on the signal strain amplitude lower than the spin-down limit for 5 of
the 11 targets over the bands searched; in the case of J1813-1749 the spin-down limit has been beaten for
the first time. For an additional 3 targets, the median upper limit across the search bands is below the
spin-down limit. This is the most sensitive narrow-band search for continuous gravitational waves carried
out so far
Hunt for new phenomena using large jet multiplicities and missing transverse momentum with ATLAS in 4.7 fb−1 of s√=7TeV proton-proton collisions
Results are presented of a search for new particles decaying to large numbers of jets in association with missing transverse momentum, using 4.7 fb−1 of pp collision data at s√=7TeV collected by the ATLAS experiment at the Large Hadron Collider in 2011. The event selection requires missing transverse momentum, no isolated electrons or muons, and from ≥6 to ≥9 jets. No evidence is found for physics beyond the Standard Model. The results are interpreted in the context of a MSUGRA/CMSSM supersymmetric model, where, for large universal scalar mass m 0, gluino masses smaller than 840 GeV are excluded at the 95% confidence level, extending previously published limits. Within a simplified model containing only a gluino octet and a neutralino, gluino masses smaller than 870 GeV are similarly excluded for neutralino masses below 100 GeV
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