197 research outputs found
Nutritive value and in vitro methane production of two perennial grasses under different stocking rates in periurban areas of West-Africa
Background. In sub-Saharan Africa, pasture is the most used practice in ruminant production, and grazing areas characteristics varied in different environment. To improve ruminants’ performances, the quality of forages represents one of the most important factors to keep under control. Objective. To quantify the effects of grazing stocking rate on the nutrient composition, energy content and in vitro fermentation characteristics including volatile fatty acids (VFA) and methane production (CH4) of two local perennial grasses Dactyloctenium aegyptium L. and Leptochloa caerulescens L. Methodology. The forage samples were collected in three locations (Zinvié, Gakpé, Adounko) characterized by different stocking rate (low, medium and high). Their chemical composition, energy content and in vitro fermentation characteristics, including CH4 production, were determined. Results. D. aegyptium showed the highest crude protein, energy content, organic matter degradability and VFA production (p<0.01) when collected in Zinvié, whereas the highest (p<0.01) structural carbohydrates (NDF) content was detected in Gakpé area and the highest CH4 production was recorded from the sample collected in Adounko (p<0.01). Contrariwise, L. caerulescens showed the highest level of crude protein and degradability (p<0.01) when collected in Zinvié, whereas it proved the highest NDF content and the lowest lignin values (p<0.01) when collected in Adounko. The highest CH4 level was obtained from the sample collected in area of Gakpé (p<0.01). Higher (p<0.01) in vitro VFA production were recorded in samples collected in Adounko and Gakpé than in the Zinvié. Implications. The results obtained in this study highlight the significant influence of urbanization and herd concentration, as well as of other environmental conditions, on the nutritional value and potential environmental impact of the studied perennial grasses. Conclusion. Samples from high grazing stocking rate locations produced more in vitro methane. Further in vivo studies are needed to confirm these results
Nutritive value and in vitro methane production of two perennial grasses under different stocking rates in periurban areas of West-Africa [Article@Valor nutritivo y producción in vitro de metano de dos pastos perennes bajo diferentes cargas de pastoreo en zonas periurbanas de áfrica occidental]
Decay modes of 250No
The Fragment Mass Analyzer at the ATLAS facility has been used to
unambiguously identify the mass number associated with different decay modes of
the nobelium isotopes produced via 204Pb(48Ca,xn)(252-x)No reactions.
Isotopically pure (>99.7%) 204Pb targets were used to reduce background from
more favored reactions on heavier lead isotopes. Two spontaneous fission
half-lives (t_1/2 = 3.7+1.1-0.8 us and 43+22-15 us) were deduced from a total
of 158 fission events. Both decays originate from 250No rather than from
neighboring isotopes as previously suggested. The longer activity most likely
corresponds to a K-isomer in this nucleus. No conclusive evidence for an alpha
branch was observed, resulting in upper limits of 2.1% for the shorter lifetime
and 3.4% for the longer activity.Comment: RevTex4, 10 pages, 5 figures, submitted to PR
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Dialkylimidazolium chloroaluminates: Ab initio calculations, Raman and neutron scattering measurements
The Raman and neutron scattering spectra of 46 mol% AlCl[sub 3] -54 mol% 1-ethyl-3-methyl imidazolium chloride (EMIC) and 67 mol% AlCl[sub 3] - 33 mol% EMIC melts are presented. Ab initio molecular orbital calculations have been carried out on structures of chloroaluminate anion and EMI cation and the interaction between anion and cation
Recommended from our members
Dialkylimidazolium Chloroaluminates: Ab Initio Calculations, Raman and Neutron Scattering Measurements
The Raman and neutron scattering spectra of 46 mol% AlCl{sub 3} -54 mol% 1-ethyl-3-methyl imidazolium chloride (EMIC) and 67 mol% AlCl{sub 3} - 33 mol% EMIC melts are presented. Ab initio molecular orbital calculations have been carried out on structures of chloroaluminate anion and EMI cation and the interaction between anion and cation
New Features in the Computational Infrastructure for Nuclear Astrophysics
A Computational Infrastructure for Nuclear Astrophysics has been developed to streamline the inclusion of the latest nuclear physics data in astrophysics simulations. The infrastructure consists of a platform-independent suite of computer codes that are freely available online at http://nucastrodata.org. The newest features of, and future plans for, this software suite are given. © Copyright owned by the author(s)
Cross Section Limits for the Pb(Kr,n)118 Reaction
In April-May, 2001, the previously reported experiment to synthesize element
118 using the Pb(Kr,n)118 reaction was repeated. No
events corresponding to the synthesis of element 118 were observed with a total
beam dose of 2.6 x 10 ions. The simple upper limit cross sections (1
event) were 0.9 and 0.6 pb for evaporation residue magnetic rigidities of 2.00
and 2.12 , respectively. A more detailed cross section calculation,
accounting for an assumed narrow excitation function, the energy loss of the
beam in traversing the target and the uncertainty in the magnetic rigidity of
the Z=118 recoils is also presented. Re-analysis of the primary data files from
the 1999 experiment showed the reported element 118 events are not in the
original data. The current results put constraints on the production cross
section for synthesis of very heavy nuclei in cold fusion reactions.Comment: 7 pages, 2 figures. Submitted to EPJ
New Outlook on the Possible Existence of Superheavy Elements in Nature
A consistent interpretation is given to some previously unexplained phenomena
seen in nature in terms of the recently discovered long-lived high spin super-
and hyper-deformed isomeric states. The Po halos seen in mica are interpreted
as due to the existence of such isomeric states in corresponding Po or nearby
nuclei which eventually decay by gamma- or beta-decay to the ground states of
210Po, 214Po and 218Po nuclei. The low-energy 4.5 MeV alpha-particle group
observed in several minerals is interpreted as due to a very enhanced alpha
transition from the third minimum of the potential-energy surface in a
superheavy nucleus with atomic number Z=108 (Hs) and atomic mass number around
271 to the corresponding minimum in the daughter.Comment: 8 pages, 8 figures, 5 tables. Paper presented at VII Int.
School-Seminar on Heavy Ion Physics, May 27 - June 1, 2002, Dubna, Russi
Impact of helminth infection during pregnancy on cognitive and motor functions of one-year-old children
Objective
To determine the effect of helminth infection during pregnancy on the cognitive and motor functions of one-year-old children.
Methods
Six hundred and thirty five singletons born to pregnant women enrolled before 29 weeks of gestation in a trial comparing two intermittent preventive treatments for malaria were assessed for cognitive and motor functions using the Mullen Scales of Early Learning, in the TOVI study, at twelve months of age in the district of Allada in Benin. Stool samples of pregnant women were collected at recruitment, second antenatal care (ANC) visit (at least one month after recruitment) and just before delivery, and were tested for helminths using the Kato-Katz technique. All pregnant women were administered a total of 600 mg of mebendazole (100 mg two times daily for 3 days) to be taken after the first ANC visit. The intake was not directly observed.
Results
Prevalence of helminth infection was 11.5%, 7.5% and 3.0% at first ANC visit, second ANC visit and at delivery, respectively. Children of mothers who were infected with hookworms at the first ANC visit had 4.9 (95% CI: 1.3–8.6) lower mean gross motor scores compared to those whose mothers were not infected with hookworms at the first ANC visit, in the adjusted model. Helminth infection at least once during pregnancy was associated with infant cognitive and gross motor functions after adjusting for maternal education, gravidity, child sex, family possessions, and quality of the home stimulation.
Conclusion
Helminth infection during pregnancy is associated with poor cognitive and gross motor outcomes in infants. Measures to prevent helminth infection during pregnancy should be reinforced
Effectiveness of a Prevention of Mother-to-Child HIV Transmission Programme in an Urban Hospital in Angola
BACKGROUND: Antiretroviral therapy is effective in reducing rates of mother-to child transmission of HIV to low levels in resource-limited contexts but the applicability and efficacy of these programs in the field are scarcely known. In order to explore such issues, we performed a descriptive study on retrospective data from hospital records of HIV-infected pregnant women who accessed in 2007-2010 the Luanda Municipal Hospital service for prevention of mother-to-child transmission (PMTCT). The main outcome measure was infant survival and HIV transmission. Our aim was to evaluate PMTCT programme in a local hospital setting in Africa. RESULTS: Data for 104 pregnancies and 107 infants were analysed. Sixty-eight women (65.4%) had a first visit before or during pregnancy and received combination antiretroviral treatment (ART) in pregnancy. The remaining 36 women (34.6%) presented after delivery and received no ART during pregnancy. Across a median cohort follow-up time of 73 weeks, mortality among women with and without ART in pregnancy was 4.4% and 16.7%, respectively (death hazard ratio: 0.30, 95% CI 0.07-1.20, p = 0.089). The estimated rates of HIV transmission or death in the infants over a median follow up time of 74 weeks were 8.5% with maternal ART during pregnancy and 38.9% without maternal ART during pregnancy. Following adjustment for use of oral zidovudine in the newborn and exposure to maternal milk, no ART in pregnancy remained associated with a 5-fold higher infant risk of HIV transmission or death (adjusted odds ratio: 5.13, 95% CI: 1.31-20.15, p = 0.019). CONCLUSIONS: Among the women and infants adhering to the PMTCT programme, HIV transmission and mortality were low. However, many women presented too late for PMTCT, and about 20% of infants did not complete follow up. This suggests the need of targeted interventions that maintain the access of mothers and infants to prevention and care services for HIV
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