993 research outputs found
Space station structures and dynamics test program
The design, construction, and operation of a low-Earth orbit space station poses challenges for development and implementation of technology. One specific challenge is the development of a dynamics test program for defining the space station design requirements, and identifying and characterizing phenomena affecting the space station's design and development. The test proposal, as outlined, is a comprehensive structural dynamics program to be launched in support of the space station (SS). Development of a parametric data base and verification of the mathematical models and analytical analysis tools necessary for engineering support of the station's design, construction, and operation provide the impetus for the dynamics test program. The four test phases planned are discussed: testing of SS applicable structural concepts; testing of SS prototypes; testing of actual SS structural hardware; and on-orbit testing of SS construction
Lignocellulose degradation mechanisms across the Tree of Life.
Organisms use diverse mechanisms involving multiple complementary enzymes, particularly glycoside hydrolases (GHs), to deconstruct lignocellulose. Lytic polysaccharide monooxygenases (LPMOs) produced by bacteria and fungi facilitate deconstruction as does the Fenton chemistry of brown-rot fungi. Lignin depolymerisation is achieved by white-rot fungi and certain bacteria, using peroxidases and laccases. Meta-omics is now revealing the complexity of prokaryotic degradative activity in lignocellulose-rich environments. Protists from termite guts and some oomycetes produce multiple lignocellulolytic enzymes. Lignocellulose-consuming animals secrete some GHs, but most harbour a diverse enzyme-secreting gut microflora in a mutualism that is particularly complex in termites. Shipworms however, house GH-secreting and LPMO-secreting bacteria separate from the site of digestion and the isopod Limnoria relies on endogenous enzymes alone. The omics revolution is identifying many novel enzymes and paradigms for biomass deconstruction, but more emphasis on function is required, particularly for enzyme cocktails, in which LPMOs may play an important role.The work of the teams at York, Portsmouth and Cambridge on development of ideas expressed in this review was supported by grants from BBSRC (BB/H531543/1, BB/L001926/1, BB/1018492/1, BB/K020358/1). The workshop was supported by a US Partnering grant from BBSRC (BB/G016208/1) to Cragg and a BBSRC/FAPESP grant to Bruce (BB/1018492/1). Watts was supported by Marie Curie FP7-RG 276948. Goodell acknowledges support from USDA Hatch Project S-1041 VA-136288. Distel acknowledges support from NSF Award IOS1442759 and NIH Award Number U19 TW008163. Beckham thanks the US Department of Energy Bioenergy Technologies Office for funding. We appreciated the hospitality of the Linnean Society in allowing us to meet in inspirational surroundings under portraits of Linnaeus, Darwin and Wallace.This is the final version of the article. It first appeared from Elsevier via http://dx.doi.org/10.1016/j.cbpa.2015.10.01
ACTH and gonadotrophin deficiency predict mortality in patients treated for nonfunctioning pituitary adenoma (NFPA): long-term follow-up of 519 patients in two large European centres
CONTEXT AND OBJECTIVE: Nonfunctioning pituitary adenomas (NFPAs) are the most common subtype of pituitary tumour. Hypopituitarism is observed in NFPAs due to tumour‐ or treatment‐related factors and may increase mortality risk. Here, we analysed the associations of hypopituitarism, hormone replacement and mortality in a large NFPA cohort derived from two large European centres. DESIGN, SETTING AND PARTICIPANTS: Case note review of all patients treated for NFPA in University Hospitals Birmingham and Beaumont Hospital Dublin between 1999 and 2014 was performed. MAIN OUTCOME MEASURES: Clinical presentation, treatment strategies, pituitary function and vitality status were recorded in each patient. A multivariate Cox regression model was used to examine the association between hypopituitarism, hormone replacement and premature mortality. RESULTS: A total of 519 patients were included in the analysis. Median duration of follow‐up was 7·0 years (0·5–43). A total of 81 deaths were recorded (15·6%). On multivariate analysis, adrenocorticotropic hormone (ACTH) and gonadotropin (Gn) deficiencies were associated with an increased relative risk of death (OR 2·26, 95% CI 1·15–4·47, P = 0·01 and OR 2·56, 95% CI 1·10–5·96, P = 0·01, respectively). Increased hydrocortisone (HC) (P‐trend = 0·02) and lower levothyroxine (LT4) doses (P‐trend = 0·03) were associated with increased risk of death. Mortality increased with the degree of pituitary failure observed (P‐trend = 0·04). CONCLUSION: ACTH and gonadotropin‐deficient patients have higher mortality rates compared to those with intact hormonal axes. Excessive HC and suboptimal LT4 replacement may also increase risk of death. Complex associations between hormone deficiency and replacement underpin the increased mortality risk in NFPA patients
The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe
The preponderance of matter over antimatter in the early Universe, the
dynamics of the supernova bursts that produced the heavy elements necessary for
life and whether protons eventually decay --- these mysteries at the forefront
of particle physics and astrophysics are key to understanding the early
evolution of our Universe, its current state and its eventual fate. The
Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed
plan for a world-class experiment dedicated to addressing these questions. LBNE
is conceived around three central components: (1) a new, high-intensity
neutrino source generated from a megawatt-class proton accelerator at Fermi
National Accelerator Laboratory, (2) a near neutrino detector just downstream
of the source, and (3) a massive liquid argon time-projection chamber deployed
as a far detector deep underground at the Sanford Underground Research
Facility. This facility, located at the site of the former Homestake Mine in
Lead, South Dakota, is approximately 1,300 km from the neutrino source at
Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino
charge-parity symmetry violation and mass ordering effects. This ambitious yet
cost-effective design incorporates scalability and flexibility and can
accommodate a variety of upgrades and contributions. With its exceptional
combination of experimental configuration, technical capabilities, and
potential for transformative discoveries, LBNE promises to be a vital facility
for the field of particle physics worldwide, providing physicists from around
the globe with opportunities to collaborate in a twenty to thirty year program
of exciting science. In this document we provide a comprehensive overview of
LBNE's scientific objectives, its place in the landscape of neutrino physics
worldwide, the technologies it will incorporate and the capabilities it will
possess.Comment: Major update of previous version. This is the reference document for
LBNE science program and current status. Chapters 1, 3, and 9 provide a
comprehensive overview of LBNE's scientific objectives, its place in the
landscape of neutrino physics worldwide, the technologies it will incorporate
and the capabilities it will possess. 288 pages, 116 figure
Measurement of the Branching Fraction for B- --> D0 K*-
We present a measurement of the branching fraction for the decay B- --> D0
K*- using a sample of approximately 86 million BBbar pairs collected by the
BaBar detector from e+e- collisions near the Y(4S) resonance. The D0 is
detected through its decays to K- pi+, K- pi+ pi0 and K- pi+ pi- pi+, and the
K*- through its decay to K0S pi-. We measure the branching fraction to be
B.F.(B- --> D0 K*-)= (6.3 +/- 0.7(stat.) +/- 0.5(syst.)) x 10^{-4}.Comment: 7 pages, 1 postscript figure, submitted to Phys. Rev. D (Rapid
Communications
Measurement of Branching Fraction and Dalitz Distribution for B0->D(*)+/- K0 pi-/+ Decays
We present measurements of the branching fractions for the three-body decays
B0 -> D(*)-/+ K0 pi^+/-B0 -> D(*)-/+ K*+/- using
a sample of approximately 88 million BBbar pairs collected by the BABAR
detector at the PEP-II asymmetric energy storage ring.
We measure:
B(B0->D-/+ K0 pi+/-)=(4.9 +/- 0.7(stat) +/- 0.5 (syst)) 10^{-4}
B(B0->D*-/+ K0 pi+/-)=(3.0 +/- 0.7(stat) +/- 0.3 (syst)) 10^{-4}
B(B0->D-/+ K*+/-)=(4.6 +/- 0.6(stat) +/- 0.5 (syst)) 10^{-4}
B(B0->D*-/+ K*+/-)=(3.2 +/- 0.6(stat) +/- 0.3 (syst)) 10^{-4}
From these measurements we determine the fractions of resonant events to be :
f(B0-> D-/+ K*+/-) = 0.63 +/- 0.08(stat) +/- 0.04(syst) f(B0-> D*-/+ K*+/-) =
0.72 +/- 0.14(stat) +/- 0.05(syst)Comment: 7 pages, 3 figures submitted to Phys. Rev. Let
Evidence for the Rare Decay B -> K*ll and Measurement of the B -> Kll Branching Fraction
We present evidence for the flavor-changing neutral current decay and a measurement of the branching fraction for the related
process , where is either an or
pair. These decays are highly suppressed in the Standard Model,
and they are sensitive to contributions from new particles in the intermediate
state. The data sample comprises
decays collected with the Babar detector at the PEP-II storage ring.
Averaging over isospin and lepton flavor, we obtain the branching
fractions and , where the
uncertainties are statistical and systematic, respectively. The significance of
the signal is over , while for it is .Comment: 7 pages, 2 postscript figues, submitted to Phys. Rev. Let
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