1,293 research outputs found
The Effect of Low Levels of Diethylstilbestrol and Plant Estrogens Upon Performance of Fattening Lambs
The excellent feeding properties of good quality legume hay and certain vegetable oil meals have long been recognized by the livestock producer. The observed feeding values of these feedstuffs cannot be attributed entirely to their classical nutrient compositions. It has been long suspected that they contain unidentified .factors that are stimulatory to growth
Photometry of Proxima Centauri and Barnard's Star Using HST Fine Guidance Sensor 3: A Search for Periodic Variations
We have observed Proxima Centauri and Barnard's Star with Hubble Space
Telescope Fine Guidance Sensor 3. Proxima Centauri exhibits small-amplitude,
periodic photometric variations. Once several sources of systematic photometric
error are corrected, we obtain 2 milli-magnitude internal photometric
precision. We identify two distinct behavior modes over the past four years:
higher amplitude, longer period; smaller amplitude, shorter period. Within the
errors one period (P ~ 83d) is twice the other. Barnard's Star shows very weak
evidence for periodicity on a timescale of approximately 130 days. If we
interpret these periodic phenomena as rotational modulation of star spots, we
identify three discrete spots on Proxima Cen and possibly one spot on Barnard's
Star. We find that the disturbances change significantly on time scales as
short as one rotation period.Comment: 39 pages, 17 figure
Akustičko–mehanički model govornog trakta
Modelling voice tract using an acoustical–mechanical analogy is shown in this article. The process of modelling voice tract is often reduced to one-dimensional acoustical model, i.e. planar waveguide model. With this acousticalmechanical model, computer programs are utilized to analyze and synthesize the voice tract. Hence, it is possible to calculate models which describe the voice tract with satisfactory quality and detail level and these models can be used in practice and applied to particular cases. In this article the process of producing a voice tract model is presented. The process includes the usage of three different computer programs, each of them dedicated to one segment of modelling. Recordings for three speakers were made and the analysis of voice parameters was performed. After the analysis is completed, a two-dimensional model of the voice tract was made, which resulted in a mechanical model consisting of specific number of tubes. Finally, the evaluation procedure for the model is done by applying a software developed specifically for this purpose, in order to determine whether the resulting model truly represents the voice tract of each speaker.Ovaj članak daje primjer izrade modela govornog trakta zasnovanog na akustičko-mehaničkim analogijama, za tri govornika, pomoću računalno zasnovanog sustava. Definiranje modela govornog trakta često se svodi na jednodimenzionalni akustički model, planarni valovodni model. Kad je napravljen akustičko-mehanički model, u analizu i sintezu uvode se računala i računalni programi. Pomoću njih se dobivaju modeli i izračuni koji sa zadovoljavajućom kvalitetom i preciznošću opisuju govorni trakt, pa takve modele možemo koristiti u praksi i primjenjivati na konkretne slučajeve. U članku su za dobivanje modela govornog trakta korištene tri različite programske podrške, svaka u svom segmentu izrade modela. Snimljena su tri govornika i napravljena je analiza glasa. Nakon toga je, opet koristeći računalo, izmodeliran dvodimenzionalni model govornog trakta, koji kao rezultat daje mehanički model s odre.enim brojem cjevčica. Na kraju je napravljena provjera tog modela sa programskom podrškom koja je napisana za tu svrhu, kako bi se utvrdilo da dobiveni model zaista predstavlja govorni trakt pojedinog govornika
Interferometric Astrometry of Proxima Centauri and Barnard's Star Using Hubble Space Telescope Fine Guidance Sensor 3: Detection Limits for sub-Stellar Companions
We report on a sub-stellar companion search utilizing interferometric
fringe-tracking astrometry acquired with Fine Guidance Sensor 3 (FGS 3) on the
Hubble Space Telescope. Our targets were Proxima Centauri and Barnard's Star.
We obtain absolute parallax values for Proxima Cen pi_{abs} = 0.7687 arcsecond
and for Barnard's Star pi_{abs} = 0.5454 arcsecond.
Once low-amplitude instrumental systematic errors are identified and removed,
our companion detection sensitivity is less than or equal to one Jupiter mass
for periods longer than 60 days for Proxima Cen. Between the astrometry and the
radial velocity results we exclude all companions with M > 0.8M_{Jup} for the
range of periods 1 < P < 1000 days. For Barnard's Star our companion detection
sensitivity is less than or equal to one Jupiter mass for periods long er than
150 days. Our null results for Barnard's Star are consistent with those of
Gatewood (1995).Comment: 35 pages, 13 figures, to appear in August 1999 A
Nonintegrability of the two-body problem in constant curvature spaces
We consider the reduced two-body problem with the Newton and the oscillator
potentials on the sphere and the hyperbolic plane .
For both types of interaction we prove the nonexistence of an additional
meromorphic integral for the complexified dynamic systems.Comment: 20 pages, typos correcte
Theory of Diluted Magnetic Semiconductor Ferromagnetism
We present a theory of carrier-induced ferromagnetism in diluted magnetic
semiconductors (III_{1-x} Mn_x V) which allows for arbitrary itinerant-carrier
spin polarization and dynamic correlations. Both ingredients are essential in
identifying the system's elementary excitations and describing their
properties. We find a branch of collective modes, in addition to the spin waves
and Stoner continuum which occur in metallic ferromagnets, and predict that the
low-temperature spin stiffness is independent of the strength of the exchange
coupling between magnetic ions and itinerant carriers. We discuss the
temperature dependence of the magnetization and the heat capacity
Theory of Magnetic Properties and Spin-Wave Dispersion for Ferromagnetic (Ga,Mn)As
We present a microscopic theory of the long-wavelength magnetic properties of
the ferromagnetic diluted magnetic semiconductor (Ga,Mn)As. Details of the host
semiconductor band structure, described by a six-band Kohn-Luttinger
Hamiltonian, are taken into account. We relate our quantum-mechanical
calculation to the classical micromagnetic energy functional and determine
anisotropy energies and exchange constants. We find that the exchange constant
is substantially enhanced compared to the case of a parabolic heavy-hole-band
model.Comment: 9 pages, 4 figure
Summer effects on body mass index (BMI) gain and growth patterns of American Indian children from kindergarten to first grade: a prospective study
<p>Abstract</p> <p>Background</p> <p>Overweight and obesity are highly prevalent among American Indian children, especially those living on reservations. There is little scientific evidence about the effects of summer vacation on obesity development in children. The purpose of this study was to investigate the effects of summer vacation between kindergarten and first grade on growth in height, weight, and body mass index (BMI) for a sample of American Indian children.</p> <p>Methods</p> <p>Children had their height and weight measured in four rounds of data collection (yielded three intervals: kindergarten, summer vacation, and first grade) as part of a school-based obesity prevention trial (Bright Start) in a Northern Plains Indian Reservation. Demographic variables were collected at baseline from parent surveys. Growth velocities (Z-score units/year) for BMI, weight, and height were estimated and compared for each interval using generalized linear mixed models.</p> <p>Results</p> <p>The children were taller and heavier than median of same age counterparts. Height Z-scores were positively associated with increasing weight status category. The mean weight velocity during summer was significantly less than during the school year. More rapid growth velocity in height during summer than during school year was observed. Obese children gained less adjusted-BMI in the first grade after gaining more than their counterparts during the previous two intervals. No statistically significant interval effects were found for height and BMI velocities.</p> <p>Conclusions</p> <p>There was no indication of a significant summer effect on children's BMI. Rather than seasonal or school-related patterns, the predominant pattern indicated by weight-Z and BMI-Z velocities might be related to age or maturation.</p> <p>Trial registration</p> <p>Bright Start: Obesity Prevention in American Indian Children Clinical Trial Govt ID# <a href="http://www.clinicaltrials.gov/ct2/show/NCT00123032">NCT00123032</a></p
IMPACT study on intervening with a manualised package to achieve treatment adherence in people with tuberculosis: protocol paper for a mixed-methods study, including a pilot randomised controlled trial
Kielmann, Karina - ORCID 0000-0001-5519-1658
https://orcid.org/0000-0001-5519-1658Introduction Compared with the rest of the UK and Western Europe, England has high rates of the infectious disease tuberculosis (TB). TB is curable, although treatment is for at least 6 months and longer when disease is drug resistant. If patients miss too many doses (non-adherence), they may transmit infection for longer and the infecting bacteria may develop resistance to the standard drugs used for treatment. Non-adherence may therefore risk both their health and that of others. Within England, certain population groups are thought to be at higher risk of non-adherence, but the factors contributing to this have been insufficiently determined, as have the best interventions to promote adherence. The objective of this study was to develop a manualised package of interventions for use as part of routine care within National Health Services to address the social and cultural factors that lead to poor adherence to treatment for TB disease.Methods and analysis This study uses a mixed-methods approach, with six study components. These are (1) scoping reviews of the literature; (2) qualitative research with patients, carers and healthcare professionals; (3) development of the intervention; (4) a pilot randomised controlled trial of the manualised intervention; (5) a process evaluation to examine clinical utility; and (6) a cost analysis.Ethics and dissemination This study received ethics approval on 24 December 2018 from Camberwell St. Giles Ethics Committee, UK (REC reference 18/LO/1818). Findings will be published and disseminated through peer-reviewed publications and conference presentations, published in an end of study report to our funder (the National Institute for Health Research, UK) and presented to key stakeholders.Trial registration number ISRCTN95243114Secondary identifying numbers University College London/University College London Hospitals Joint Research Office 17/0726.
National Institute for Health Research, UK 16/88/06.https://doi.org/10.1136/bmjopen-2019-032760http://bmjopen.bmj.com/cgi/content/full/bmjopen-2019-0327609pubpub1
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