1,859 research outputs found
Polar foliations and isoparametric maps
A singular Riemannian foliation on a complete Riemannian manifold is
called a polar foliation if, for each regular point , there is an immersed
submanifold , called section, that passes through and that meets
all the leaves and always perpendicularly. A typical example of a polar
foliation is the partition of into the orbits of a polar action, i.e., an
isometric action with sections. In this work we prove that the leaves of
coincide with the level sets of a smooth map if is simply
connected. In particular, we have that the orbits of a polar action on a simply
connected space are level sets of an isoparametric map. This result extends
previous results due to the author and Gorodski, Heintze, Liu and Olmos, Carter
and West, and Terng.Comment: 9 pages; The final publication is available at springerlink.com
http://www.springerlink.com/content/c72g4q5350g513n1
Relative toxicity of gossypol enantiomers in broilers
Use of cottonseed meal in poultry diets has
been avoided in large part because of fear of gossypol
toxicity. Gossypol exists naturally as a mixture of 2 enantiomers
that exhibit different biological activities. Two experiments
were conducted to determine the relative toxicity
of gossypol enantiomers on broilers. In the first experiment,
3-d-old broilers were fed a standard diet containing
0, 100, 200, 300, or 400 mg of gossypol from gossypol
acetic acid per kilogram of diet from 3 to 42 d of age.
This form of gossypol contains both enantiomers in an
equimolar ratio. Each dietary treatment consisted of 6
replicate pens of 4 birds. In the second experiment, 3-dold
broilers were divided into 15 pens of 4 birds each
and fed a standard diet supplemented with either no
gossypol or one of the gossypol enantiomers at 200 or
400 mg/kg of diet from 3 to 21 d of age. In both experiments,
feed intake and BW gain were measured. In addi-
(Key words: cottonseed meal, gossypol, gossypol enantiomer, broiler)
2005 Poultry Science 84:1376–1382
INTRODUCTION
Cottonseed meal (CSM) could be an attractive alternative
protein source for poultry diets, but concern over
the presence of the potentially toxic agent, gossypol, has
limited its use. Gossypol [1,1′,6,6′,7,7′-hexahydroxy-5,5′-
diisopropyl-3, 3′-dimethyl-(2, 2′- binaphthalene)-8, 8′-dicarboxaldehyde]
is a polyphenolic compound located in
pigment glands that are distributed throughout the cotton
plant. Gossypol is composed of 2 naphthalene rings with
restricted rotation around the bond connecting the rings.
As a result of this restricted rotation, gossypol occurs
naturally as a mixture of 2 enantiomers [(+)- and (−)-
2005 Poultry Science Association, Inc.
Received for publication February 7, 2005.
Accepted for publication May 5, 2005.
1This research was supported in part by grant 2631RE683-118 from
the Georgia Cotton Commission, Perry, GA.
2Mention of trade names or commercial products in this article is
solely for the purpose of providing specific information and does not
imply recommendation or endorsement by the US Department of Agriculture.
3To whom correspondence should be addressed: [email protected].
1376
tion, several organ and tissue samples were collected at
21 d (experiments 1 and 2) and 42 d (experiment 1) of
age and analyzed for gossypol. In experiment 1, feed
consumption and BW gain were reduced (P < 0.05) at 21
and 42 d for the birds fed the highest level of gossypol.
The concentration of gossypol in the heart, kidney, and
plasma were equivalent at 21 and 42 d of age. In experiment
2, total feed consumption was reduced only in birds
consuming (−)-gossypol, but BW gains were lower for
birds fed either enantiomer. However, (−)-gossypol was
more detrimental to growth than (+)-gossypol. The liver
had the highest tissue concentration of both enantiomers,
and accumulation of (+)-gossypol was higher than (−)-
gossypol in all tissues examined. No racemization of the
enantiomers was apparent in the tissues analyzed. Our
results indicated that both gossypol enantiomers were
toxic to broilers but that (−)-gossypol was more harmful
to efficient broiler production than (+)-gossypol
Relative toxicity of gossypol enantiomers in laying and broiler breeder hens
Gossypol, a natural component of cottonseed
meal, exists in positive (+) or negative (−) enantiomeric
forms, and their levels and ratio could be altered
by developing new genetic strains of cotton. Two experiments
were conducted to determine the relative toxicity of
the individual gossypol enantiomers in laying and broiler
breeder hens. In the first experiment, 25 individually
caged Hy-Line W-36 forty-three-week-old laying hens
were fed a standard corn-soy diet supplemented with
either no gossypol or the individual enantiomers at 200
and 400 mg/kg of diet for 20 d (5 hens/treatment). In
the second experiment, 15 individually caged Cobb 500
fast-feathering 44-wk-old broiler breeder hens were fed
a standard corn-soy-wheat middlings diet supplemented
with either no gossypol or the individual enantiomers at
400 mg/kg of diet for 18 d (5 hens/treatment). In both
experiments, feed intake, egg production, and egg weight
were determined daily. All eggs were individually
opened and scored for yolk discoloration. At the end of
both experiments, several organ and tissue samples were
collected for gossypol analyses. In both experiments, the
addition of (+)-gossypol to the diet reduced egg production.
Only laying and broiler breeder hens fed (+)-gossypol
produced eggs with severe yolk discoloration (score
≥ 4). Total feed intake was lower (P < 0.05) in laying hens
fed the 400 mg/kg level of (+)-gossypol compared with
laying hens fed the other dietary treatments. In contrast,
broiler breeder hens consumed less of the diet supplemented
with (−)-gossypol. In both experiments, tissue
accumulation of (+)-gossypol was higher than (−)-gossypol,
with the exception of bile and excreta. The results
suggest that in hens the ingestion of (+)-gossypol has a
greater effect on egg yolk discoloration than the consumption
of (−)-gossypol
Exploring employment opportunities through microtasks via cybercafes
Microwork in cybercafés is a promising tool for
poverty alleviation. For those who cannot afford a computer,
cybercafés can serve as a simple payment channel and as a
platform to work. However, there are questions about whether
workers are interested in working in cybercafés, whether
cybercafé owners are willing to host such a set up, and whether
workers are skilled enough to earn an acceptable pay rate? We
designed experiments in internet/cyber cafes in India and Kenya
to investigate these issues. We also investigated whether
computers make workers more productive than mobile
platforms? In surveys, we found that 99% of the users wanted to
continue with the experiment in cybercafé, while 8 of 9 cybercafé
owners showed interest to host this experiment. User typing speed
was adequate to earn a pay rate comparable to their existing
wages, and the fastest workers were approximately twice as
productive usi
Drum vortons in high density QCD
Recently it was shown that high density QCD supports of number of topological
defects. In particular, there are U(1)_Y strings that arise due to K^0
condensation that occurs when the strange quark mass is relatively large. The
unique feature of these strings is that they possess a nonzero K^+ condensate
that is trapped on the core. In the following we will show that these strings
(with nontrivial core structure) can form closed loops with conserved charge
and currents trapped on the string worldsheet. The presence of conserved
charges allows these topological defects, called vortons, to carry angular
momentum, which makes them classically stable objects. We also give arguments
demonstrating that vortons carry angular momentum very efficiently (in terms of
energy per unit angular momentum) such that they might be the important degrees
of freedom in the cores of neutron stars.Comment: 11 pages, accepted for publication in Physical Review
Denosumab, raloxifene, romosozumab and teriparatide to prevent osteoporotic fragility fractures: a systematic review and economic evaluation
Background
Fragility fractures are fractures that result from mechanical forces that would not ordinarily result in fracture.
Objectives
The objectives were to evaluate the clinical effectiveness, safety and cost-effectiveness of non-bisphosphonates {denosumab [Prolia®; Amgen Inc., Thousand Oaks, CA, USA], raloxifene [Evista®; Daiichi Sankyo Company, Ltd, Tokyo, Japan], romosozumab [Evenity®; Union Chimique Belge (UCB) S.A. (Brussels, Belgium) and Amgen Inc.] and teriparatide [Forsteo®; Eli Lilly and Company, Indianapolis, IN, USA]}, compared with each other, bisphosphonates or no treatment, for the prevention of fragility fracture.
Data sources
For the clinical effectiveness review, nine electronic databases (including MEDLINE, EMBASE and the World Health Organization International Clinical Trials Registry Platform) were searched up to July 2018.
Review methods
A systematic review and network meta-analysis of fracture and femoral neck bone mineral density were conducted. A review of published economic analyses was undertaken and a model previously used to evaluate bisphosphonates was adapted. Discrete event simulation was used to estimate lifetime costs and quality-adjusted life-years for a simulated cohort of patients with heterogeneous characteristics. This was done for each non-bisphosphonate treatment, a strategy of no treatment, and the five bisphosphonate treatments previously evaluated. The model was populated with effectiveness evidence from the systematic review and network meta-analysis. All other parameters were estimated from published sources. An NHS and Personal Social Services perspective was taken, and costs and benefits were discounted at 3.5% per annum. Fracture risk was estimated from patient characteristics using the QFracture® (QFracture-2012 open source revision 38, Clinrisk Ltd, Leeds, UK) and FRAX® (web version 3.9, University of Sheffield, Sheffield, UK) tools. The relationship between fracture risk and incremental net monetary benefit was estimated using non-parametric regression. A probabilistic sensitivity analysis and scenario analyses were used to assess uncertainty.
Results
Fifty-two randomised controlled trials of non-bisphosphonates were included in the clinical effectiveness systematic review and an additional 51 randomised controlled trials of bisphosphonates were included in the network meta-analysis. All treatments had beneficial effects compared with placebo for vertebral, non-vertebral and hip fractures, with hazard ratios varying from 0.23 to 0.94, depending on treatment and fracture type. The effects on vertebral fractures and the percentage change in bone mineral density were statistically significant for all treatments. The rate of serious adverse events varied across trials (0–33%), with most between-group differences not being statistically significant for comparisons with placebo/no active treatment, non-bisphosphonates or bisphosphonates. The incremental cost-effectiveness ratios were > £20,000 per quality-adjusted life-year for all non-bisphosphonate interventions compared with no treatment across the range of QFracture and FRAX scores expected in the population eligible for fracture risk assessment. The incremental cost-effectiveness ratio for denosumab may fall below £30,000 per quality-adjusted life-year at very high levels of risk or for high-risk patients with specific characteristics. Raloxifene was dominated by no treatment (resulted in fewer quality-adjusted life-years) in most risk categories.
Limitations
The incremental cost-effectiveness ratios are uncertain for very high-risk patients.
Conclusions
Non-bisphosphonates are effective in preventing fragility fractures, but the incremental cost-effectiveness ratios are generally greater than the commonly applied threshold of £20,000–30,000 per quality-adjusted life-year.
Study registration
This study is registered as PROSPERO CRD42018107651.
Funding
This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 29. See the NIHR Journals Library website for further project information
Light Lambda-Lambda Hypernuclei and the Onset of Stability for Lambda-Xi Hypernuclei
New Faddeev-Yakubovsky calculations for light Lambda-Lambda hypernuclei are
presented in order to assess the self consistency of the Lambda-Lambda
hypernuclear binding-energy world data and the implied strength of the
Lambda-Lambda interaction, in the wake of recent experimental reports on
Lambda-Lambda-4H and Lambda-Lambda-6He. Using Gaussian soft-core simulations of
Nijmegen one-boson-exchange model interactions, the Nijmegen soft-core model
NSC97 simulations are found close to reproducing the recently reported binding
energy of Lambda-Lambda-6He, but not those of other species. For stranger
systems, Faddeev calculations of light Lambda-Xi hypernuclei, using a
simulation of the strongly attractive Lambda-Xi interactions due to the same
model, suggest that Lambda-Xi-6He marks the onset of nuclear stability for Xi
hyperons.Comment: 5 pages, 3 postscript figures; fig.2 replaced, minor changes,
accepted as Rapid Communication in PR
Temperature Variation of Ultra Slow Light in a Cold Gas
A model is developed to explain the temperature dependence of the group
velocity as observed in the experiments of Hau et al (Nature {\bf397}, 594
(1999)). The group velocity is quite sensitive to the change in the spatial
density. The inhomogeneity in the density and its temperature dependence are
primarily responsible for the observed behavior.Comment: 12 pages, 4 figure
Pesos e relações de peso de bezerros filhos de vacas nelore e cruzadas canchim x nelore
A Study on Drug-Drug Interaction of Esomeprazole and Anti-Diabetic Drugs
Drug–drug interaction between esomeprazole at therapeutic and higher doses and sulfonylureas was studied. Sulfonylureas (tolbutamide 40 mg/kg and glibenclamide 40 µg/kg) were administered and the time to onset of hypoglycemia, the duration of the hypoglycemia, and the peak hypoglycemia were determined. Esomeprazole (1.8 mg/kg, 3.6 mg/kg, and 30 mg/kg) was administered for 8 days and its influence on sulfonylurea-induced hypoglycemia was studied. Therapeutic doses of esomeprazole, i.e., 1.8 mg/kg and 3.6 mg/kg dose did not influence the hypoglycemia induced by sulfonylureas. However, a higher dose, i.e., 30 mg/kg, did significantly enhance the duration of hypoglycemia and the peak hypolgycemia. Esomeprazole (30 mg/kg) by itself did not reduce the blood glucose levels; therefore, a pharmacodynamic type of drug interaction can be ruled out. Similarly, a pharmacokinetic type of drug interaction may be ruled out at therapeutic doses. The CYP isoenzyme system involved in the metabolism of sulfonylureas are not very sensitive to esomeprazole and the dose and frequency of administration of sulfonylurea need not be readjusted when they are used concomitantly with esomeprazole (at therapeutic doses)
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