6,147 research outputs found
Nonfactorization in Hadronic Two-body Cabibbo-favored decays of D^0 and D^+
With the inclusion of nonfactorized amplitudes in a scheme with , we
have studied Cabibbo-favored decays of and into two-body hadronic
states involving two isospins in the final state. We have shown that it is
possible to understand the measured branching ratios and determined the sizes
and signs of nonfactorized amplitudes required.Comment: 15 pages, Late
Computer Simulation of Current Forces on Motion of Floating Production Storage and Offloading in Irregular Waves
This paper presents the effect of current forces on the motion of forces on Floating Production Storage and Offloading (FPSO) in irregular waves. The objective of this research is to compute the motion of FPSO in irregular waves by time domain simulation including the effect of current forces. A study is made on the slowly varying oscillations of a moored single body system in a current and waves. Linear potential theory is used to describe the fluid motion, and three-dimensional source distribution techniques are applied to obtain the hydrodynamic forces and transfer function of the wave exciting forces. OCIMF (1994) data are used for estimation of the current forces. The non-linear time domain simulations have been carried out in irregular waves. Based on it, slowly varying motion responses are examined including the effect of the current forces. Several environmental conditions, such as the current angle of attack, current velocity, significant wave height and mean wave period are considered, which may significantly affect FPSO motion in surge, sway and yaw moments. It is found that the effect of current forces is quite significant when the current velocity is increased. In this simulation, while the current velocity is increased to 3.0 meter/seconds, the impact on FPSO motion is quite significant, which should be taken into consideration from the point of view of safety, failure of mooring systems, operating responses and the dynamic positioning of the FPSO
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Demographics and Outcomes of Pulmonary Hypertension Patients in United States Emergency Departments
Introduction: Pulmonary hypertension (PH) is a common, yet under-diagnosed, contributor to morbidity and mortality. Our objective was to characterize the prevalence of PH among adult patients presenting to United States (US) emergency departments (ED) and to identify demographic patterns and outcomes of PH patients in the ED.Methods: We analyzed the Nationwide Emergency Department Sample (NEDS) database, with a focus on ED patients aged 18 years and older, with any International Classification of Diseases, Clinical Modification (ICD)-9-CM or ICD-10-CM diagnosis code for PH from 2011 to 2015. The primary outcome was inpatient, all-cause mortality. The secondary outcomes were hospital admission rates and hospital length of stay (LOS).Results: From 2011 to 2015, in a sample of 121,503,743 ED visits, representing a weighted estimate of 545,500,486 US ED visits, patients with a diagnosis of PH accounted for 0.78% (95% confidence interval [CI], 0.75- 0.80%) of all US ED visits. Of the PH visits, 86.9% were admitted to the hospital, compared to 16.3% for all other ED visits (P <0.001). Likewise, hospital LOS and hospital-based mortality were higher in the PH group than for other ED patients (e.g., inpatient mortality 4.5% vs 2.6%, P < 0.001) with an adjusted odds ratio (aOR) of 1.34 (95% CI, 1.31â1.37). Age had the strongest association with mortality, with an aOR of 10.6 for PH patients over 80 years (95% CI, 10.06â11.22), compared to a reference of ages 18 to 30 years.Conclusion: In this nationally representative sample, presentations by patients with PH were relatively common, accounting for nearly 0.8% of US ED visits. Patients with PH were significantly more likely to be admitted to the hospital than all other patients, had longer hospital LOS, and increased risk of inpatient mortality
Inelastic Final-State Interactions and Two-body Hadronic B decays into Single-Isospin channels
The role of inelastic final-state interactions in CP asymmetries and
branching ratios is investigated in certain chosen single isospin two-body
hadronic B decays. Treating final-state interactions through Pomeron and Regge
exchanges, we demonstrate that inelastic final state interactions could lead to
sizeable effects on the CP asymmetry.Comment: 23 pages, Latex, 1 eps-figur
Relationship between spot and futures prices: The case of global food commodities
Global debates about determining the direction of relationship between commodity futures and spot prices reflect the importance of this issue. Resolving the debate will guide different economic agents to make correct decisions. The aim of this paper is to empirically investigate the direction of relationship between food spot and futures prices using different methodologies so as to resolve the debate. In addition, it is important to know which market could cause price volatilities to the other market, and thus, addressing price volatilities in a correct way. The paper conducts linear and non-linear ranger causality tests along with cointegration and error correction model and concludes with mixed findings. Specifically, linear and nonlinear Granger causality tests found evidence that food futures prices cause food spot prices. This suggests that food futures markets lead the price discovery process, and hence, the direction of information flows goes from food futures markets to food spot markets, and accordingly, any price volatilities in futures markets lead to price volatilities in spot markets. In contrast, the cointegration and error correction model found evidence that food spot prices cause food futures prices. This suggests that food spot markets lead the price discovery process, and hence, the direction of information flows goes from food spot markets to food futures markets, and accordingly any price volatilities in food spot markets lead to price volatilities in futures markets. Based on these differences in the obtained results, the current paper suggests the cointegration and error correction model is preferable since it provides a more formal framework for examining the short-run dynamics and testing for the equilibrium relationship among economic variables. Special attention to alternative instruments, such as the implementation of a global virtual reserve, should be highlighted so as to minimize speculative attacks and avoid excessive spikes of prices in spot and futures markets. This implies the importance of adopting the possible protectionist measures by developing countries in order to hedge against the negative reflections of global food price volatility.
Key words: Food markets, futures prices, spot prices, causality tests, cointegration analysi
Baryons and baryonic matter in the large Nc and heavy quark limits
This paper explores properties of baryons and finite density baryonic matter
in an artificial world in which Nc, the number of colors, is large and the
quarks of all species are degenerate and much larger than {\Lambda}_QCD. It has
long been known that in large Nc QCD, baryons composed entirely of heavy quarks
are accurately described in the mean-field approximation. However, the detailed
properties of baryons in the combined large Nc and heavy quark limits have not
been fully explored. Here some basic properties of baryons are computed using a
variational approach. At leading order in both the large Nc and heavy quark
expansions the baryon mass is computed explicitly as is the baryon form factor.
Baryonic matter, the analog of nuclear matter in this artificial world, should
also be well described in the mean-field approximation. In the special case
where all baryons have an identical spin flavor structure, it is shown that in
the formal heavy quark and large Nc limit interactions between baryons are
strictly repulsive at low densities. The energy per baryon is computed in this
limit and found to be exponentially small. It is shown that when the
restriction to baryons with an identical spin-flavor structure is dropped, a
phase of baryonic matter exists with a density of 2Nf times that for the
restricted case but with the same energy (where Nf is the number of degenerate
flavors). It is shown that this phase is at least metastable.Comment: 19 page
Nonfactorization and Color-Suppressed Decays
Using value of the parameter but including a modest
nonfactorized amplitude, we show that it is possible to understand all data,
including polarization, for color-suppressed
decays in all commonly used models of form factors. We show that for decay one can define an effective , which is process-dependent and,
in general, complex; but it is not possible to define an effective for
decay. We also explain why nonfactorized amplitudes do not
play a significant role in color-favored B decays.Comment: 13 pages, Latex, one figure (not included
Reduced axonal diameter of peripheral nerve fibres in a mouse model of Rett syndrome
Rett syndrome (RTT) is a neurological disorder characterized by motor and cognitive impairment, autonomic dysfunction and a loss of purposeful hand skills. In the majority of cases, typical RTT is caused by de novo mutations in the X-linked gene, MECP2. Alterations in the structure and function of neurons within the central nervous system of RTT patients and Mecp2-null mouse models are well established. In contrast, few studies have investigated the effects of MeCP2-deficiency on peripheral nerves. In this study, we conducted detailed morphometric as well as functional analysis of the sciatic nerves of symptomatic adult female Mecp2+/- mice. We observed a significant reduction in the mean diameter of myelinated nerve fibers in Mecp2+/- mice. In myelinated fibers, mitochondrial densities per unit area of axoplasm were significantly altered in Mecp2+/- mice. However, conduction properties of the sciatic nerve of Mecp2 knockout mice were not different from control. These subtle changes in myelinated peripheral nerve fibers in heterozygous Mecp2 knockout mice could potentially explain some RTT phenotypes
Ground State Spin Structure of Strongly Interacting Disordered 1D Hubbard Model
We study the influence of on-site disorder on the magnetic properties of the
ground state of the infinite U 1D Hubbard model. We find that the ground state
is not ferromagnetic. This is analyzed in terms of the algebraic structure of
the spin dependence of the Hamiltonian. A simple explanation is derived for the
1/N periodicity in the persistent current for this model.Comment: 3 pages, no figure
Community Structure of Grouper Fish (Serranidae) Landed in Peukan Bada Subdistrict, Aceh Province
Information on important and economic grouper fish (Serranidae family) in Peukan Bada waters, Province of Aceh is very limited. This objecives of this research were to determine spatial and temporal variabilities in species composition and community structure of grouper landed in Peukan Bada, Aceh Besar District. The research was conducted using survey method during February to June 2015 on three fish landing sites i.e., Ujong Pancu, Lamtengoh, and Lamteh. The groupers were caught by using handline. The landed fishes were therefore counted and identified up to species level. The data were also analyzed based on taxonomic information and individual number of each species, community structure using the diversity index (H\u27), eveness (E), and dominance (D). The results obtained 835 individual, 21 species of grouper belong to 4 genera (Aethaloperca, Cephalopholis, Epinephelus dan Variola). Based on species, Epinephelus fasciatus and Cephalopholis sonnerati were the most grouper fishes in the region. Based on community structure, diversity value (H\u27) in Lam-tengoh was higher than that in Ujong Pancu and Lamteh. Total grouper fish catches were not significantly different (P>0,05) among the three region. Meanwhile, total grouper fish cacthes were significantly different between seasons (p<0,05). The diversity species variation during five months of observation was affected by the differences in catches area, the condition of aquatic enviroment, and oceanographic condition
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