571 research outputs found
Characterization of Awassi lamb fattening systems: a Syrian case study
Intensive lamb fattening systems are evolving in developing Middle Eastern countries due to high demand for lambs at favorable prices; however, little is known about their characteristics and constraints. A survey was conducted in Syria involving 241 farmers to characterize the fattening production systems and main constraints, with emphasis on feeding, management, labor, and marketing. Most farmers (90%) considered the income from fattening to be from medium to high, and 57% expressed that lamb fattening along with alternative income sources compose the family's livelihood strategies. Fattening systems offer employment to family members. Market price was the main decision factor to buy and sell lambs, but this was only part of various marketing aspects. Male lambs usually bought at markets at the mean age of 4 months (mean weight of 31 kg) are sold after fattening at a 50–60 kg weight range. The average yearly fattening cycle was 2.7 batches, and the average number of lambs per batch was 232. For 65% (n = 241) of the farmers the major constraint to fattening was feeding cost, and for about a half of farmers (51%, n = 241), disease outbreaks and prices for veterinarian services constituted the second important constraint. Research on least-cost fattening diets and curbing disease problems to increase farmer's income margins is needed. It is expected that due to existing commonalities, the information emerging from this study regarding major constraints to Awassi lamb fattening systems could be useful for an across-synthesis on Awassi fattening production in the regionFil: Wiedemann Hartwell, Birgitte. International Center for Agricultural Research in Dry Areas; Siria. University of Natural Resources and Applied Life Sciences. Department of Sustainable Agricultural Systems. Division of Livestock Sciences; Austria. Fredensborg; DinamarcaFil: Iñiguez, Luis. International Center for Agricultural Research in Dry Areas; SiriaFil: Mueller, Joaquin Pablo. Instituto Nacional de TecnologÃa Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche; ArgentinaFil: Wurzinger, Maria. University of Natural Resources and Applied Life Sciences. Department of Sustainable Agricultural Systems. Division of Livestock Sciences; AustriaFil: Knaus, W.F. University of Natural Resources and Applied Life Sciences. Department of Sustainable Agricultural Systems. Division of Livestock Sciences; Austri
Varied Signature Splitting Phenomena in Odd Proton Nuclei
Varied signature splitting phenomena in odd proton rare earth nuclei are
investigated. Signature splitting as functions of and in the angular
momentum projection theory is explicitly shown and compared with those of the
particle rotor model. The observed deviations from these rules are due to the
band mixings. The recently measured Ta high spin data are taken as a
typical example where fruitful information about signature effects can be
extracted. Six bands, two of which have not yet been observed, were calculated
and discussed in detail in this paper. The experimentally unknown band head
energies are given
How magic is the magic 68Ni nucleus?
We calculate the B(E2) strength in 68Ni and other nickel isotopes using
several theoretical approaches. We find that in 68Ni the gamma transition to
the first 2+ state exhausts only a fraction of the total B(E2) strength, which
is mainly collected in excited states around 5 MeV. This effect is sensitive to
the energy splitting between the fp shell and the g_{9/2}orbital. We argue that
the small experimental B(E2) value is not strong evidence for the double-magic
character of 68Ni.Comment: 4 pages, 4 figure
Role of carbon dioxide and ion transport in the formation of sub-embryonic fluid by the blastoderm of the Japanese quail
1. The explanted blastoderm of the Japanese quail was used to explore the role of ions and carbon dioxide in determining the rate of sub-embryonic fluid (SEF) production between 54 and 72 h of incubation.
2. Amiloride, an inhibitor of Na+/H+ exchange, at concentrations of 10-3 to 10-6 M substantially decreased the rate of SEF production when added to the albumen culture medium. N-ethylmaleimide, an inhibitor of V type H+ ATPase, also decreased this rate but only to a small extent at the highest dose applied, 10-3 M. Both inhibitors had no effect on SEF production when added to the SEF. 3. The inhibitors of cellular bicarbonate and chloride exchange, 4-acetamido-4-'isothiocyano-2, 2-'disulphonic acid (SITS) and 4,4'diisothiocyanostilbene-2,2-'disulphonic acid (DIDS), had no effect upon SEF production.
4. Ouabain, an inhibitor of Na+/K+ ATPase, decreased SEF production substantially at all concentrations added to the SEF (10-3 to 10-6 M). Three sulphonamide inhibitors of carbonic anhydrase, acetazolamide, ethoxzolamide and benzolamide, decreased SEF production when added to the SEF at concentrations of 10-3 to 10-6 M. Benzolamide was by far the most potent. Neither ouabain nor the sulphonamides altered SEF production when added to the albumen culture medium.
5. Using a cobalt precipitation method, carbonic anhydrase activity was localised to the endodermal cells of the area vasculosa. The carbonic anhydrase activity was primarily associated with the lateral plasma membranes, which together with the potent inhibitory effect of benzolamide, suggests the carbonic anhydrase of these cells is the membrane-associated form, CA IV.
6. The changes in SEF composition produced by inhibitors were consistent with the production of SEF by local osmotic gradients.
7. It is concluded that a Na+/K+ ATPase is located on the basolateral membranes of the endodermal cells of the area vasculosa , and that a sodium ion/hydrogen ion exchanger is located on their apical surfaces. Protons for this exchanger would be provided by the hydration of CO2 catalysed by the membrane-associated carbonic anhydrase. Furthermore, it is proposed that the prime function of the endodermal cells of the area vasculosa is the production of SEF
Rapid disappearance of perennial ice on Canada's most northern lake
Field records, aerial photographs, and satellite imagery show that the perennial ice cover on Ward Hunt Lake at Canada's northern coast experienced rapid contraction and thinning after at least 50 years of relative stability. On all dates of sampling from 1953 to 2007, 3.5 to 4.3 m of perennial ice covered 65-85% of the lake surface in summer. The ice cover thinned from 2008 onward, and the lake became ice free in 2011, an event followed by 26 days of open water conditions in 2012. This rapid ice loss corresponded to a significant increase in melting degree days (MDD), from a mean (±SD) of 80.4 (±36.5) MDD (1996-2007) to 136.2 (±16.4) MDD (2008-2012). The shallow bathymetry combined with heat advection by warm inflows caused feedback effects that accelerated the ice decay. These observations show how changes across a critical threshold can result in the rapid disappearance of thick perennial ice
Dynamic response of an Arctic epishelf lake to seasonal and long-term forcing: Implications for ice shelf thickness
Changes in the depth of the freshwater-seawater interface in epishelf lakes have been used to infer long-term changes in the minimum thickness of ice shelves; however, little is known about the dynamics of epishelf lakes and what other factors may influence their depth. Continuous observations collected between 2011 and 2014 in the Milne Fiord epishelf lake, in the Canadian Arctic, showed that the depth of the halocline varied seasonally by up to 3.3m, which was comparable to interannual variability. The seasonal depth variation was controlled by the magnitude of surface meltwater inflow and the hydraulics of the inferred outflow pathway, a narrow basal channel in the Milne Ice She
Low-lying quadrupole collective states of the light and medium Xenon isotopes
Collective low lying levels of light and medium Xenon isotopes are deduced
from the Generalized Bohr Hamiltonian (GBH). The microscopic seven functions
entering into the GBH are built from a deformed mean field of the Woods-Saxon
type. Theoretical spectra are found to be close to the ones of the experimental
data taking into account that the calculations are completely microscopic, that
is to say, without any fitting of parameters.Comment: 8 pages, 4 figures, 1 tabl
Level structures of 96,97,98Ru at high angular momentum
The high-spin level structures of 96,97,98Ru (Z544) have been investigated using the 65Cu(36S, pxn)96,97,98Ru (x54,3,2) reactions. About 130 new transitions have been observed and unambiguously placed in the decay schemes of these nuclei. The level schemes have been extended up to spin J'22– 34\, and excitation energies Ex'20224 MeV. Spherical shell model calculations have been performed and theoretical level energies compared with experimental values. Calculations using 88Sr as the core give a reasonable agreement for the observed energy levels up to J16\), possibly manifesting vibrational behavior
Nuclear structure of 94,95Mo at high spins
The high-spin level structures of 94,95Mo (N552,53) have been investigated via the 65Cu(36S, a p2n)94Mo and 65Cu(36S, a pn)95Mo reactions at 142 MeV. The level schemes have been extended up to spin J'19\ and excitation energies Ex'12 MeV. Spherical shell-model calculations have been performed and compared with the experimental energy levels. The level structure of 94Mo exhibits a single-particle nature and the higher-angular-momentum states are dominated by the excitation of a g9/2 neutron across the N550 shell gap. The level sequences observed in 95Mo have been interpreted on the basis of the spherical shell model and weak coupling of a d5/2 or a g7/2 neutron to the 94Mo core
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