1,904 research outputs found
The Vietnamese shrimp trade: livelihoods analysis of stakeholders and market chain analysis
Aquaculture and capture fisheries in Vietnam have been increasing fast in the last decade, especially aquaculture growth rate is 12% for the 1999 – 2003 period, contributing a significant part into the hunger eradication and poverty reduction1. Vietnam is to be ranked into one of the countries potential to produce the aquatic economic in the world, and the fact is that, after 40 years of establishing, the fisheries sector has made remarkable contributions to the country. By the list, at the moment the aquatic products make up about 4 - 5% of GDP and create job opportunities for over 3 three million
employees (VASEP, 2004), in which the largest contribution is from shrimp farming. [PDF contains 124 pages.
Vitrification of a monatomic 2D simple liquid
A monatomic simple liquid in two dimensions, where atoms interact
isotropically through the Lennard-Jones-Gauss potential [M. Engel and H.-R.
Trebin, Phys. Rev. Lett. 98, 225505 (2007)], is vitrified by the use of a rapid
cooling technique in a molecular dynamics simulation. Transformation to a
crystalline state is investigated at various temperatures and the
time-temperature-transformation (TTT) curve is determined. It is found that the
transformation time to a crystalline state is the shortest at a temerature 14%
below the melting temperature Tm and that at temperatures below Tv = 0.6 Tm the
transformation time is much longer than the available CPU time. This indicates
that a long-lived glassy state is realized for T < Tv.Comment: 5pages,5figures,accepted for publication in CEJ
The relationship of erectile dysfunction and subclinical cardiovascular disease: A systematic review and meta-analysis
Erectile dysfunction (ED) is associated with cardiovascular disease (CVD) and CVD mortality. However, the relationship between ED and subclinical CVD is less clear. We synthesized the available data on the association of ED and measures of subclinical CVD. We searched multiple databases for published literature on studies examining the association of ED and measures of subclinical CVD across four domains: endothelial dysfunction measured by flow-mediated dilation (FMD), carotid intima–media thickness (cIMT), coronary artery calcification (CAC), and other measures of vascular function such as the ankle–brachial index, toe–brachial index, and pulse wave velocity. We conducted random effects meta-analysis and meta-regression on studies that examined an ED relationship with FMD (15 studies; 2025 participants) and cIMT (12 studies; 1264 participants). ED was associated with a 2.64 percentage-point reduction in FMD compared to those without ED (95% CI: –3.12, −2.15). Persons with ED also had a 0.09-mm (95% CI: 0.06, 0.12) higher cIMT than those without ED. In subgroup meta-analyses, the mean age of the study population, study quality, ED assessment questionnaire (IIEF-5 or IIEF-15), or the publication date did not significantly affect the relationship between ED and cIMT or between ED and FMD. The results for the association of ED and CAC were inconclusive. In conclusion, this study confirms an association between ED and subclinical CVD and may shed additional light on the shared mechanisms between ED and CVD, underscoring the importance of aggressive CVD risk assessment and management in persons with ED
State of the science on controversial topics: missing maxillary lateral incisors--a report of the Angle Society of Europe 2012 meeting.
BACKGROUND: The optimal long-term management of the congenitally missing maxillary lateral incisor continues to cause controversy within the specialty. The Angle Society of Europe meeting 2012 dedicated a day to address some of the current controversies relating to the management of these missing lateral incisors. FINDINGS: The format of the day consisted of morning presentations and afternoon breakout sessions to discuss a variety of questions related to the management of missing lateral incisors. CONCLUSIONS: The consensus viewpoint from this day was that the care of patients with congenitally missing lateral incisors is best achieved through a multi-disciplinary approach. The current evidence base is weak, and further well-designed, prospective trials are needed
An Efficient Representation of Euclidean Gravity I
We explore how the topology of spacetime fabric is encoded into the local
structure of Riemannian metrics using the gauge theory formulation of Euclidean
gravity. In part I, we provide a rigorous mathematical foundation to prove that
a general Einstein manifold arises as the sum of SU(2)_L Yang-Mills instantons
and SU(2)_R anti-instantons where SU(2)_L and SU(2)_R are normal subgroups of
the four-dimensional Lorentz group Spin(4) = SU(2)_L x SU(2)_R. Our proof
relies only on the general properties in four dimensions: The Lorentz group
Spin(4) is isomorphic to SU(2)_L x SU(2)_R and the six-dimensional vector space
of two-forms splits canonically into the sum of three-dimensional vector spaces
of self-dual and anti-self-dual two-forms. Consolidating these two, it turns
out that the splitting of Spin(4) is deeply correlated with the decomposition
of two-forms on four-manifold which occupies a central position in the theory
of four-manifolds.Comment: 31 pages, 1 figur
Theory of differential inclusions and its application in mechanics
The following chapter deals with systems of differential equations with
discontinuous right-hand sides. The key question is how to define the solutions
of such systems. The most adequate approach is to treat discontinuous systems
as systems with multivalued right-hand sides (differential inclusions). In this
work three well-known definitions of solution of discontinuous system are
considered. We will demonstrate the difference between these definitions and
their application to different mechanical problems. Mathematical models of
drilling systems with discontinuous friction torque characteristics are
considered. Here, opposite to classical Coulomb symmetric friction law, the
friction torque characteristic is asymmetrical. Problem of sudden load change
is studied. Analytical methods of investigation of systems with such
asymmetrical friction based on the use of Lyapunov functions are demonstrated.
The Watt governor and Chua system are considered to show different aspects of
computer modeling of discontinuous systems
Segmentation of diagnostic tissue compartments on whole slide images with renal thrombotic microangiopathies (TMAs)
The thrombotic microangiopathies (TMAs) manifest in renal biopsy histology
with a broad spectrum of acute and chronic findings. Precise diagnostic
criteria for a renal biopsy diagnosis of TMA are missing. As a first step
towards a machine learning- and computer vision-based analysis of wholes slide
images from renal biopsies, we trained a segmentation model for the decisive
diagnostic kidney tissue compartments artery, arteriole, glomerulus on a set of
whole slide images from renal biopsies with TMAs and Mimickers (distinct
diseases with a similar nephropathological appearance as TMA like severe benign
nephrosclerosis, various vasculitides, Bevacizumab-plug glomerulopathy,
arteriolar light chain deposition disease). Our segmentation model combines a
U-Net-based tissue detection with a Shifted windows-transformer architecture to
reach excellent segmentation results for even the most severely altered
glomeruli, arterioles and arteries, even on unseen staining domains from a
different nephropathology lab. With accurate automatic segmentation of the
decisive renal biopsy compartments in human renal vasculopathies, we have laid
the foundation for large-scale compartment-specific machine learning and
computer vision analysis of renal biopsy repositories with TMAs.Comment: 12 pages, 3 figure
Compared to conventional, ecological intensive management promotes beneficial proteolytic soil microbial communities for agro-ecosystem functioning under climate change-induced rain regimes
Projected climate change and rainfall variability will affect soil microbial communities, biogeochemical cycling and agriculture. Nitrogen (N) is the most limiting nutrient in agroecosystems and its cycling and availability is highly dependent on microbial driven processes. In agroecosystems, hydrolysis of organic nitrogen (N) is an important step in controlling soil N availability. We analyzed the effect of management (ecological intensive vs. conventional intensive) on N-cycling processes and involved microbial communities under climate change-induced rain regimes. Terrestrial model ecosystems originating from agroecosystems across Europe were subjected to four different rain regimes for 263 days. Using structural equation modelling we identified direct impacts of rain regimes on N-cycling processes, whereas N-related microbial communities were more resistant. In addition to rain regimes, management indirectly affected N-cycling processes via modifications of N-related microbial community composition. Ecological intensive management promoted a beneficial N-related microbial community composition involved in N-cycling processes under climate change-induced rain regimes. Exploratory analyses identified phosphorus-associated litter properties as possible drivers for the observed management effects on N-related microbial community composition. This work provides novel insights into mechanisms controlling agro-ecosystem functioning under climate change
Hidden attractors in fundamental problems and engineering models
Recently a concept of self-excited and hidden attractors was suggested: an
attractor is called a self-excited attractor if its basin of attraction
overlaps with neighborhood of an equilibrium, otherwise it is called a hidden
attractor. For example, hidden attractors are attractors in systems with no
equilibria or with only one stable equilibrium (a special case of
multistability and coexistence of attractors). While coexisting self-excited
attractors can be found using the standard computational procedure, there is no
standard way of predicting the existence or coexistence of hidden attractors in
a system. In this plenary survey lecture the concept of self-excited and hidden
attractors is discussed, and various corresponding examples of self-excited and
hidden attractors are considered
Quantum numbers of the state and orbital angular momentum in its decay
Angular correlations in decays, with , and , are used to measure
orbital angular momentum contributions and to determine the value of
the meson. The data correspond to an integrated luminosity of 3.0
fb of proton-proton collisions collected with the LHCb detector. This
determination, for the first time performed without assuming a value for the
orbital angular momentum, confirms the quantum numbers to be .
The is found to decay predominantly through S wave and an upper limit
of at C.L. is set on the fraction of D wave.Comment: 16 pages, 4 figure
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