3,393 research outputs found
Inelastic diffractive scattering in nonperturbative QCD
We examine diffractive proton-proton scattering p p -> p X and photo- and
electroproduction of \rho^0 mesons \gamma^(*) p -> \rho^0 X, where X denotes a
proton or a final state, into which the proton can go by diffractive
dissociation. Using a functional integral approach we derive the scattering
amplitudes, which are governed by the expectation values of light-like
Wegner-Wilson loops, which are then evaluated using the model of the stochastic
vacuum. For the proton, we assume a quark-diquark structure. From the
scattering amplitudes we calculate total and differential cross sections for
high centre of mass energy and small momentum transfer and compare with
experiments. Furthermore we calculate isovector form factors for the proton and
the pion within the same model.Comment: 32 pages, 11 figures, v3: revised chapter 5, added appendix B, to be
published in Eur.Phys.J.
Magnetometer suitable for Earth field measurement based on transient atomic response
We describe the development of a simple atomic magnetometer using Rb
vapor suitable for Earth magnetic field monitoring. The magnetometer is based
on time-domain determination of the transient precession frequency of the
atomic alignment around the measured field. A sensitivity of 1.5 nT/
is demonstrated on the measurement of the Earth magnetic field in the
laboratory. We discuss the different parameters determining the magnetometer
precision and accuracy and predict a sensitivity of 30 pT/Comment: 6 pages, 5 figure
Genome sequences of 15 Gardnerella vaginalis strains isolated from the vaginas of women with and without bacterial vaginosis
Gardnerella vaginalis is a predominant species in bacterial vaginosis, a dysbiosis of the vagina that is associated with adverse health outcomes, including preterm birth. Here, we present the draft genome sequences of 15 Gardnerella vaginalis strains (now available through BEI Resources) isolated from women with and without bacterial vaginosis
The genetic determinants of recurrent somatic mutations in 43,693 blood genomes
Nononcogenic somatic mutations are thought to be uncommon and inconsequential. To test this, we analyzed 43,693 National Heart, Lung and Blood Institute Trans-Omics for Precision Medicine blood whole genomes from 37 cohorts and identified 7131 non-missense somatic mutations that are recurrently mutated in at least 50 individuals. These recurrent non-missense somatic mutations (RNMSMs) are not clearly explained by other clonal phenomena such as clonal hematopoiesis. RNMSM prevalence increased with age, with an average 50-year-old having 27 RNMSMs. Inherited germline variation associated with RNMSM acquisition. These variants were found in genes involved in adaptive immune function, proinflammatory cytokine production, and lymphoid lineage commitment. In addition, the presence of eight specific RNMSMs associated with blood cell traits at effect sizes comparable to Mendelian genetic mutations. Overall, we found that somatic mutations in blood are an unexpectedly common phenomenon with ancestry-specific determinants and human health consequences
Genome sequence of Acetomicrobium hydrogeniformans OS1
Acetomicrobium hydrogeniformans, an obligate anaerobe of the phylum Synergistetes, was isolated from oil production water. It has the unusual ability to produce almost 4 molecules H2/molecule glucose. The draft genome of A. hydrogeniformans OS1 (DSM 22491T) is 2,123,925 bp, with 2,068 coding sequences and 60 RNA genes
There is a low rate of major adverse cardiovascular events in chest pain patients with a moderate risk heart score referred from urgent care for expedited outpatient cardiology evaluation: a multi-center study
Background The HEART score is an effective method of risk stratifying emergency department (ED) patients with chest pain. The rate of major adverse cardiovascular events (MACE) in patients with moderate HEART score referred from an urgent care (UC) for an expedited outpatient cardiology evaluation for 11 months was described in 133 patients in a previous study. This is a follow-up study with 18 months of data and 206 patients.Aim. The primary outcome was to examine the rate of MACE when patients with moderate HEART score were referred for an expedited outpatient cardiology follow-up after evaluation in urgent care. The secondary outcome was to determine if there is a decrease in rate of ED transfer after this protocol was introduced.Methods. A cross-sectional study was conducted by a multispecialty group in Las Vegas, Nevada, which included 206 patients with a HEART score of 4 to 6 (i.e.: moderate risk) who presented to one of five UC centers with chest pain or an anginal equivalent. A streamlined evaluation protocol to assess each HEART score component was adopted by all UC providers to facilitate an expedited outpatient cardiology follow-up, as an alternative to referral to the emergency department. Data was collected from February 14, 2019 through August 13, 2020. The population was followed for 6 weeks with a primary endpoint of MACE determined by electronic medical record review and direct phone contact with patients. Outcomes were confirmed in 98% of patients. Chest pain transfer data was compared between 12 months prior to implementing HEART protocol and 18 months of data analysis while using the new protocol.Results. Over the course of 18 months, 206 patients with a moderate risk HEART score were referred to outpatient cardiology in an expedited manner. The average age was 65 with 53% female and 47% male patients. 150 patients (73% of the 206) were seen within 3 days, 114 (55%) underwent stress testing, 6 (3%) had coronary computed tomography angiogram, and 6 (3%) received an invasive coronary angiogram. Five patients were found to have MACE: one patient who had a non-ST-elevation myocardial infarction and subsequent coronary stent, two patients were found to have obstructive disease after coronary angiography with subsequent coronary artery bypass graft, one patient had an abnormal stress test and subsequent coronary stent, and one patient had critical mitral stenosis, multi-vessel coronary artery disease and underwent coronary artery bypass graft with mitral valve replacement with complications of renal failure and COVID-19 and expired. The emergency department referral rate declined by 21%.Conclusion. Patients with a moderate risk HEART score referred from UC for an expedited outpatient cardiology evaluation had a low rate of MACE and no deaths due to delay of care. There was also a significant decrease in the rate of ED referrals.Background. The HEART score is an effective method of risk stratifying emergency department (ED) patients with chest pain. The rate of major adverse cardiovascular events (MACE) in patients with moderate HEART score referred from an urgent care (UC) for an expedited outpatient cardiology evaluation for 11 months was described in 133 patients in a previous study. This is a follow-up study with 18 months of data and 206 patients.Aim. The primary outcome was to examine the rate of MACE when patients with moderate HEART score were referred for an expedited outpatient cardiology follow-up after evaluation in urgent care. The secondary outcome was to determine if there is a decrease in rate of ED transfer after this protocol was introduced.Methods. A cross-sectional study was conducted by a multispecialty group in Las Vegas, Nevada, which included 206 patients with a HEART score of 4 to 6 (i.e.: moderate risk) who presented to one of five UC centers with chest pain or an anginal equivalent. A streamlined evaluation protocol to assess each HEART score component was adopted by all UC providers to facilitate an expedited outpatient cardiology follow-up, as an alternative to referral to the emergency department. Data was collected from February 14, 2019 through August 13, 2020. The population was followed for 6 weeks with a primary endpoint of MACE determined by electronic medical record review and direct phone contact with patients. Outcomes were confirmed in 98% of patients. Chest pain transfer data was compared between 12 months prior to implementing HEART protocol and 18 months of data analysis while using the new protocol.Results. Over the course of 18 months, 206 patients with a moderate risk HEART score were referred to outpatient cardiology in an expedited manner. The average age was 65 with 53% female and 47% male patients. 150 patients (73% of the 206) were seen within 3 days, 114 (55%) underwent stress testing, 6 (3%) had coronary computed tomography angiogram, and 6 (3%) received an invasive coronary angiogram. Five patients were found to have MACE: one patient who had a non-ST-elevation myocardial infarction and subsequent coronary stent, two patients were found to have obstructive disease after coronary angiography with subsequent coronary artery bypass graft, one patient had an abnormal stress test and subsequent coronary stent, and one patient had critical mitral stenosis, multi-vessel coronary artery disease and underwent coronary artery bypass graft with mitral valve replacement with complications of renal failure and COVID-19 and expired. The emergency department referral rate declined by 21%.Conclusion. Patients with a moderate risk HEART score referred from UC for an expedited outpatient cardiology evaluation had a low rate of MACE and no deaths due to delay of care. There was also a significant decrease in the rate of ED referrals
Northrop Grumman TR202 LOX/LH2 Deep Throttling Engine Technology Project Status
NASA's Propulsion and Cryogenic Advanced Development (PCAD) project is currently developing enabling propulsion technologies in support of future lander missions. To meet lander requirements, several technical challenges need to be overcome, one of which is the ability for the descent engine(s) to operate over a deep throttle range with cryogenic propellants. To address this need, PCAD has enlisted Northrop Grumman Aerospace Systems (NGAS) in a technology development effort associated with the TR202 engine. The TR202 is a LOX/LH2 expander cycle engine driven by independent turbopump assemblies and featuring a variable area pintle injector similar to the injector used on the TR200 Apollo Lunar Module Descent Engine (LMDE). Since the Apollo missions, NGAS has continued to mature deep throttling pintle injector technology. The TR202 program has completed two series of pintle injector testing. The first series of testing used ablative thrust chambers and demonstrated igniter operation as well as stable performance at discrete points throughout the designed 10:1 throttle range. The second series was conducted with calorimeter chambers and demonstrated injector performance at discrete points throughout the throttle range as well as chamber heat flow adequate to power an expander cycle design across the throttle range. This paper provides an overview of the TR202 program, describing the different phases and key milestones. It describes how test data was correlated to the engine conceptual design. The test data obtained has created a valuable database for deep throttling cryogenic pintle technology, a technology that is readily scalable in thrust level
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