229 research outputs found
Overview of the LADEE Ultraviolet-visible Spectrometer: Design, Performance and Planned Operations
The Lunar Atmosphere and Dust Environment Explorer (LADEE) is an orbital lunar science mission currently under development to address the goals of the 2003 National Research Council decadal survey, the Lunar Exploration Analysis Group Roadmap, and the "Scientific Context for Exploration of the Moon" (SCEM) report, and has been recommended for execution by the 2011 Planetary Missions Decadal Survey. The mission s focus is to study the pristine state of the lunar atmosphere and dust environment prior to possible lunar exploration activities by countries, including the United States, China, India, and Japan, among others. Activity on the lunar surface has the potential of altering the tenuous lunar atmosphere, but changing the type and concentration of gases in the atmosphere. Before these activities occur it is important to make measurements of the current lunar atmosphere in its unmodified state. LADEE will determine the composition of the lunar atmosphere and investigate the processes that control its distribution and variability, including sources, sinks, and surface interactions. It will monitor variations in known gases, such as sodium, potassium, argon and helium, and will search for other, as-yet-undetected gases of both lunar and extra-lunar origin. LADEE will also determine whether dust is present in the lunar exosphere, and reveal the processes that contribute to its sources and variability. Launch is planned for August, 2013
The Ames Vertical Gun Range
The Ames Vertical Gun Range (AVGR) is a national facility for conducting laboratory- scale investigations of high-speed impact processes. It provides a set of light-gas, powder, and compressed gas guns capable of accelerating projectiles to speeds up to 7 km s(exp -1). The AVGR has a unique capability to vary the angle between the projectile-launch and gravity vectors between 0 and 90 deg. The target resides in a large chamber (diameter approximately 2.5 m) that can be held at vacuum or filled with an experiment-specific atmosphere. The chamber provides a number of viewing ports and feed-throughs for data, power, and fluids. Impacts are observed via high-speed digital cameras along with investigation-specific instrumentation, such as spectrometers. Use of the range is available via grant proposals through any Planetary Science Research Program element of the NASA Research Opportunities in Space and Earth Sciences (ROSES) calls. Exploratory experiments (one to two days) are additionally possible in order to develop a new proposal
Critical temperature for the nuclear liquid-gas phase transition (from multifragmentation and fission)
Critical temperature Tc for the nuclear liquid-gas phase transition is
stimated both from the multifragmentation and fission data. In the first
case,the critical temperature is obtained by analysis of the IMF yields in
p(8.1 GeV)+Au collisions within the statistical model of multifragmentation
(SMM). In the second case, the experimental fission probability for excited
188Os is compared with the calculated one with Tc as a free parameter. It is
concluded for both cases that the critical temperature is higher than 16 MeV.Comment: 15 pages, 8 figure
An archived activation tagged population of Arabidopsis thaliana to facilitate forward genetics approaches
BACKGROUND:Functional genomics tools provide researchers with the ability to apply high-throughput techniques to determine the function and interaction of a diverse range of genes. Mutagenised plant populations are one such resource that facilitate gene characterisation. They allow complex physiological responses to be correlated with the expression of single genes in planta, through either reverse genetics where target genes are mutagenised to assay the affect, or through forward genetics where populations of mutant lines are screened to identify those whose phenotype diverges from wild type for a particular trait. One limitation of these types of populations is the prevalence of gene redundancy within plant genomes, which can mask the affect of individual genes. Activation or enhancer populations, which not only provide knock-out but also dominant activation mutations, can facilitate the study of such genes.RESULTS:We have developed a population of almost 50,000 activation tagged A. thaliana lines that have been archived as individual lines to the T3 generation. The population is an excellent tool for both reverse and forward genetic screens and has been used successfully to identify a number of novel mutants. Insertion site sequences have been generated and mapped for 15,507 lines to enable further application of the population, while providing a clear distribution of T-DNA insertions across the genome. The population is being screened for a number of biochemical and developmental phenotypes, provisional data identifying novel alleles and genes controlling steps in proanthocyanidin biosynthesis and trichome development is presented.CONCLUSION:This publicly available population provides an additional tool for plant researcher's to assist with determining gene function for the many as yet uncharacterised genes annotated within the Arabidopsis genome sequence http://aafc-aac.usask.ca/FST. The presence of enhancer elements on the inserted T-DNA molecule allows both knock-out and dominant activation phenotypes to be identified for traits of interest
Red Dragon: Low-cost Access to the Surface of Mars using Commercial Capabilities
We will discuss the feasibility of using a minimally-modified variant of a SpaceX Dragon capsule as a low-cost, large-capacity, near-term, Mars lander for scientific and human-precursor missions. We have been evaluating such a Red Dragon platform as an option for a Discovery Program mission concept. A Red Dragon lander has the potential to be low cost primarily because it would be derived from a routinely-flying spacecraft. Dragon is being developed to ferry cargo and crew to and from the International Space Station (ISS). The cargo variant is currently undergoing test flights, which will be followed by standard ISS cargo missions and, eventually, crewed flights. The human variant, unlike other Earth-return vehicles, appears to also have most of the capabilities necessary to land on Mars. In particular, it has a set of high-thrust, throttleable, storable bi-propellant Super- Draco engines integrated directly into the capsule which are intended for launch abort and powered landings on Earth. These thrusters suggest the possibility of a parachute-free, fully-propulsive deceleration at Mars from supersonic speeds to the surface. Concepts for large, human-relevant landers (see, e.g., [1]) also often employ supersonic retro-propulsion; Red Dragon's entry, descent, and landing approach would scale to those landers. Further, SpaceX's Falcon Heavy launch vehicle, currently under development and expected to have its first flight in 2013, will be capable of sending Dragon on a trajectory to Mars. We will discuss our motivation for exploring a Red Dragon lander, the primary technical questions which determine its feasibility, and the current results of our analysis. In particular, we will examine entry, descent, and landing (EDL) in detail. We will describe the modifications to Dragon necessary for interplanetary cruise, EDL, and operations on the Martian surface
Whole Mount in situ Localization of miRNAs and mRNAs During Somatic Embryogenesis in Arabidopsis
Somatic embryogenesis (SE) results from the transition of differentiated plant somatic
cells into embryogenic cells that requires the extensive reprogramming of the somatic
cell transcriptome. Commonly, the SE-involved genes are identified by analyzing the
heterogeneous population of explant cells and thus, it is necessary to validate the
expression of the candidate genes in the cells that are competent for embryogenic
transition. Here, we optimized and implemented the whole mount in situ hybridization
(WISH) method (Bleckmann and Dresselhaus, 2016; Dastidar et al., 2016) in order to
analyze the spatiotemporal localization of miRNAs (miR156, miR166, miR390, miR167)
and mRNAs such as WOX5 and PHABULOSA-target of miR165/166 during the SE
that is induced in Arabidopsis explants. This study presents a detailed step-by-step
description of the WISH procedure in which DIG-labeled LNA and RNA probes were
used to detect miRNAs and mRNAs, respectively. The usefulness of the WISH in the
functional analysis of the SE-involved regulatory pathways is demonstrated and the
advantages of this method are highlighted: (i) the ability to analyze intact non-sectioned
plant tissue; (ii) the specificity of transcript detection; (iii) the detection of miRNA; and (iv)
a semi-quantitative assessment of the RNA abundance
Influence of Sleeve Gastrectomy on NASH and Type 2 Diabetes Mellitus
Background. Nonalcoholic fatty liver disease is present in up to 85% of adipose patients and may proceed to nonalcoholic steatohepatitis (NASH). With insulin resistance and obesity being the main risk factors for NASH, the effect of isolated sleeve gastrectomy (ISG) on these parameters was examined. Methods. 236 patients underwent ISG with intraoperative liver biopsy from December 2002 to September 2009. Besides demographic data, pre-operative weight/BMI, HbA1c, AST, ALT, triglycerides, HDL and LDL levels were determined. Results. A significant correlation of NASH with higher HbA1c, AST and ALT and lower levels for HDL was observed (P < .05, <.0001, <.0001, <.01, resp.). Overall BMI decreased from 45.0 ± 6.8 to 29.7 ± 6.5 and 31.6 ± 4.4 kg/m2 at 1 and 3 years. An impaired weight loss was demonstrated for patients with NASH and patients with elevated HbA1c (plateau 28.08 kg/m2 versus 29.79 kg/m2 and 32.30 kg/m2 versus 28.79 kg/m2, resp.). Regarding NASH, a significant improvement of AST, ALT, triglyceride and HDL levels was shown (P < .0001 for all). A resolution of elevated HbA1c was observed in 21 of 23 patients. Summary. NASH patients showed a significant loss of body weight and amelioration of NASH status. ISG can be successfully performed in these patients and should be recommended for this subgroup
Trichostatin A Triggers an Embryogenic Transition in Arabidopsis Explants via an Auxin-Related Pathway
Auxin is an important regulator of plant ontogenies including embryo development and
the exogenous application of this phytohormone has been found to be necessary for
the induction of the embryogenic response in plant explants that have been cultured
in vitro. However, in the present study, we show that treatment of Arabidopsis explants
with trichostatin A (TSA), which is a chemical inhibitor of histone deacetylases, induces
somatic embryogenesis (SE) without the exogenous application of auxin. We found that
the TSA-treated explants generated somatic embryos that developed efficiently on the
adaxial side of the cotyledons, which are the parts of an explant that are involved in
auxin-induced SE. A substantial reduction in the activity of histone deacetylase (HDAC)
was observed in the TSA-treated explants, thus confirming a histone acetylationrelated
mechanism of the TSA-promoted embryogenic response. Unexpectedly, the
embryogenic effect of TSA was lower on the auxin-supplemented media and this finding
further suggests an auxin-related mechanism of TSA-induced SE. Congruently, we
found a significantly increased content of indolic compounds, which is indicative of IAA
and an enhanced DR5::GUS signal in the TSA-treated explants. In line with these results,
two of the YUCCA genes (YUC1 and YUC10), which are involved in auxin biosynthesis,
were found to be distinctly up-regulated during TSA-induced SE and their expression
was colocalised with the explant sites that are involved in SE. Beside auxin, ROS were
extensively accumulated in response to TSA, thereby indicating that a stress-response
is involved in TSA-triggered SE. Relevantly, we showed that the genes encoding the
transcription factors (TFs) that have a regulatory function in auxin biosynthesis including
LEC1, LEC2, BBM, and stress responses (MYB118) were highly up-regulated in the
TSA-treated explants. Collectively, the results provide several pieces of evidence about
the similarities between the molecular pathways of SE induction that are triggered by
TSA and 2,4-D that involve the activation of the auxin-responsive TF genes that have
a regulatory function in auxin biosynthesis and stress responses. The study suggests
the involvement of histone acetylation in the auxin-mediated release of the embryogenic
program of development in the somatic cells of Arabidopsis
A P-glycoprotein homologue of Plasmodium falciparum is localized on the digestive vacuole.
How risky is caring for emergency patients at risk of malpractice litigation: a population based epidemiological study of Taiwan's experiences
<p>Abstract</p> <p>Background</p> <p>Emergency medicine has generally been considered a high risk specialty. The purpose of this study is to assess the risk of being sued in the district courts for caring emergency room (ER) patients from the perspective of epidemiology.</p> <p>Methods</p> <p>This research was designed to be a retrospective population based cohort study. We intended to find out the incidence of litigations arising from ER patients and that of birth inpatients in Taiwan, and computed their relative risks. The inclusion criterion was set to be incidents transpired in the time period of 1998 to 2002. The study materials included the reimbursement claim dataset of the National Health Insurance from 1998 to 2002, and the district court decision database of the Judicial Yuan from 1999 to 2006.</p> <p>Results</p> <p>The average annual incidence rate of becoming a plaintiff for ER patients is 0.86 per million, and for birth patients is 33.5 per million. There is a statistically significant difference between birth patients and ER patients. The relative risk comparing ER patients against birth inpatients is 0.03.</p> <p>Conclusion</p> <p>The findings of this population based study indicate that the patient population emergency physicians are facing in Taiwan have relatively lower risks of developing litigation in comparison with the patients that come to give birth. Due to the large volume of ER patients, malpractice still pose a major threat in the emergency department, and misdiagnosis remains the major complaint of plaintiffs in subsequent litigations.</p
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