1,325 research outputs found
Observed Coupling of the Mesosphere Inversion Layer to the Thermal Tidal Structure
Rayleigh lidar observations of mesosphere temperature profiles obtained from 40 to ∼100 km from Logan, Utah (41.7, 111.8 W, altitude, 1.9 km) over 10 nights in late February, 1995, revealed an interesting development between 60 to 75 km of a winter mesosphere inversion layer with an amplitude of ∼20–30 K and a downward phase progression of ∼1 km/hr. The data also showed two altitude regions exhibiting significant cooling of 10–30 K in extent. These were located below and above the peak of the inversion layer, respectively, at altitudes of ∼50–55 km and ∼70–80 km. When these results were compared with the predictions of a global wave scale model (GSWM), the observed thermal mesosphere structure is similar to the computed composite tidal structure based upon the semi‐diurnal and diurnal tides with the exception that observed amplitudes of heating and cooling are ∼10x larger than predicted GSWM values. We suggest that these events over Utah are caused through a localized mechanism involving the coupling of gravity waves to the mesopause tidal structure
A pulsed, mono-energetic and angular-selective UV photo-electron source for the commissioning of the KATRIN experiment
The KATRIN experiment aims to determine the neutrino mass scale with a
sensitivity of 200 meV/c^2 (90% C.L.) by a precision measurement of the shape
of the tritium -spectrum in the endpoint region. The energy analysis of
the decay electrons is achieved by a MAC-E filter spectrometer. To determine
the transmission properties of the KATRIN main spectrometer, a mono-energetic
and angular-selective electron source has been developed. In preparation for
the second commissioning phase of the main spectrometer, a measurement phase
was carried out at the KATRIN monitor spectrometer where the device was
operated in a MAC-E filter setup for testing. The results of these measurements
are compared with simulations using the particle-tracking software
"Kassiopeia", which was developed in the KATRIN collaboration over recent
years.Comment: 19 pages, 16 figures, submitted to European Physical Journal
A Community-Driven Approach to Identifying “Winnableâ€? Policies Using the Centers for Disease Control and Prevention’s Common Community Measures for Obesity Prevention
Federally funded, community-based participatory research initiatives encourage the development and implementation of obesity prevention policies. In 2009, the Centers for Disease Control and Prevention (CDC) published the Common Community Measures for Obesity Prevention (COCOMO), which include recommended strategies and measures to guide communities in identifying and evaluating environmental and policy strategies to prevent obesity. Agreeing on "winnable" policy issues can be challenging for community members. We used CDC's COCOMO to structure in-depth interviews and group discussions with local stakeholders (ie, planners, town managers, and a local community advisory council) to stimulate interest in and identify health-promoting policies for local policy and planning agendas. We first asked stakeholders to rank the COCOMO recommendations according to feasibility and likelihood of success given community culture, infrastructure, extent of leadership support, and likely funding support. Rankings were used to identify the most and least "winnable" COCOMO policy strategies. We then used questions from the evidence-based Community Readiness Handbook to aid discussion with stakeholders on the facilitators and barriers to enacting the most and least winnable policy options identified. Finally, we discuss potential adaptations to COCOMO for rural jurisdictions
Simulation-Based Design of Drive Mechanism for Flapping Wing Miniature Air Vehicles
Flapping wing miniature air vehicles (MAVs) have significant potential in surveillance, search, rescue and reconnaissance applications. These applications require the MAV to carry payloads in the form of batteries, on-board cameras, camera, sensors etc. In order to ensure that the payload capacity of the MAV is maximized for a given wing area and flapping frequency, we need to carefully design the drive mechanism to reduce its mass and ensure that it meets the intended functional requirements. The overall design approach described in this chapter incorporates the advances in modeling and simulations methods in kinematic and dynamic analysis, finite element analysis, and manufacturability analysis. We demonstrate applicability this design approach using two case studies
Discovering the New Standard Model: Fundamental Symmetries and Neutrinos
This White Paper describes recent progress and future opportunities in the
area of fundamental symmetries and neutrinos.Comment: Report of the Fundamental Symmetries and Neutrinos Workshop, August
10-11, 2012, Chicago, I
A Monte Carlo simulation of the Sudbury Neutrino Observatory proportional counters
The third phase of the Sudbury Neutrino Observatory (SNO) experiment added an
array of 3He proportional counters to the detector. The purpose of this Neutral
Current Detection (NCD) array was to observe neutrons resulting from
neutral-current solar neutrino-deuteron interactions. We have developed a
detailed simulation of the current pulses from the NCD array proportional
counters, from the primary neutron capture on 3He through the NCD array
signal-processing electronics. This NCD array Monte Carlo simulation was used
to model the alpha-decay background in SNO's third-phase 8B solar-neutrino
measurement.Comment: 38 pages; submitted to the New Journal of Physic
Experimental constraints on a dark matter origin for the DAMA annual modulation effect
A claim for evidence of dark matter interactions in the DAMA experiment has
been recently reinforced. We employ a new type of germanium detector to
conclusively rule out a standard isothermal galactic halo of Weakly Interacting
Massive Particles (WIMPs) as the explanation for the annual modulation effect
leading to the claim. Bounds are similarly imposed on a suggestion that dark
pseudoscalars mightlead to the effect. We describe the sensitivity to light
dark matter particles achievable with our device, in particular to
Next-to-Minimal Supersymmetric Model candidates.Comment: v4: introduces recent results from arXiv:0807.3279 and
arXiv:0807.2926. Sensitivity to pseudoscalars is revised in light of the
first. Discussion on the subject adde
Genetic polymorphisms in the catechol estrogen metabolism pathway and breast cancer risk
Background: This study investigated whether single nucleotide polymorphisms (SNPs) in genes within the catechol estrogen metabolism pathway altered the risk of breast cancer alone or in combination, as well as whether menopausal hormone therapy (HT) modified the effect of these SNPs on breast cancer risk.
Methods: In a population-based case-control study of breast cancer, 891 cases and 878 controls were genotyped for six functional SNPs in the COMT, CYP1B1, GSTM1, GSTP1, and GSTT1 genes.
Results: Women homozygous with the T allele in CYP1B1*2 (Ser119; rs1056827) were at 1.69 (95% confidence interval [CI]: 1.17-2.46) times the risk of women homozygous with the G allele; women homozygous with the G allele in GSTP1 (Val105; rs1695) were at 0.73 (95% CI: 0.54-0.99) times the risk of breast cancer compared to women homozygous with the A allele. No other SNPs tested were associated with breast cancer to any appreciable degree. Potential gene-gene and gene-HT interactions were investigated.
Conclusion: With the exception of GSTP1 and possibly CYP1B1*2, our findings do not provide support for the role of genetic variation in the catechol estrogen metabolism pathway and breast cancer risk in post-menopausal women
The BNO-LNGS joint measurement of the solar neutrino capture rate in 71Ga
We describe a cooperative measurement of the capture rate of solar neutrinos
by the reaction 71Ga(\nu_e,e^-)71Ge. Extractions were made from a portion of
the gallium target in the Russian-American Gallium Experiment SAGE and the
extraction samples were transported to the Gran Sasso laboratory for synthesis
and counting at the Gallium Neutrino Observatory GNO. Six extractions of this
type were made and the resultant solar neutrino capture rate was 64
^{+24}_{-22} SNU, which agrees well with the overall result of the gallium
experiments. The major purpose of this experiment was to make it possible for
SAGE to continue their regular schedule of monthly solar neutrino extractions
without interruption while a separate experiment was underway to measure the
response of 71Ga to neutrinos from an 37Ar source. As side benefits, this
experiment proved the feasibility of long-distance sample transport in ultralow
background radiochemical experiments and familiarized each group with the
methods and techniques of the other.Comment: 7 pages, no figures; minor additions in version
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