9,861 research outputs found

    Gender Roles in Small Holder Dairy Farming: Pertinent Issues on Access and Control over Dairy Farming in Arumeru District, Tanzania

    Get PDF
    A study on gender roles in dairy farming and management was conducted in Arumeru district, Tanzania. The study involved women in dairy farming groups and those not in groups. The objective of this study was to assess gender role in dairy farming and management, access and control over income obtained as well as, animal ownership, decision making  and opportunities in dairy farming system in Arumeru. Cross sectional research design was adopted using structured questionnaires to collect information from households from six villages namely Bangata, Sasi, Inshupu, Enaboishu, Sokoni II and Nkoaranga. Descriptive analysis and Chi-square were used to test the statistical significance of categorical and continuous data respectively. The results showed that women contribute more labour force in dairy management than men, those women who were not in groups did not have a full access and control over dairy farming enterprise. Furthermore, it was observed that those women in groups were in a good position to overcome traditional practice. Women who belonged to groups controlled and had access to resources such as livestock (dairy cattle) and income generated from them. However, since most of the farmer groups were still infants, it has been recommended that the women groups should get financial assistance from the government agencies. Similarly, in conjunction with encouraging more women to join groups, gender relations in dairy management should be reassessed to minimize the work load burden to women which affects the level of production and sustainability of the dairy enterprise. Keywords: Access and control, dairy management, gender, women groups.

    The asymptotic quasi-stationary states of the two-dimensional magnetically confined plasma and of the planetary atmosphere

    Full text link
    We derive the differential equation governing the asymptotic quasi-stationary states of the two dimensional plasma immersed in a strong confining magnetic field and of the planetary atmosphere. These two systems are related by the property that there is an intrinsic constant length: the Larmor radius and respectively the Rossby radius and a condensate of the vorticity field in the unperturbed state related to the cyclotronic gyration and respectively to the Coriolis frequency. Although the closest physical model is the Charney-Hasegawa-Mima (CHM) equation, our model is more general and is related to the system consisting of a discrete set of point-like vortices interacting in plane by a short range potential. A field-theoretical formalism is developed for describing the continuous version of this system. The action functional can be written in the Bogomolnyi form (emphasizing the role of Self-Duality of the asymptotic states) but the minimum energy is no more topological and the asymptotic structures appear to be non-stationary, which is a major difference with respect to traditional topological vortex solutions. Versions of this field theory are discussed and we find arguments in favor of a particular form of the equation. We comment upon the significant difference between the CHM fluid/plasma and the Euler fluid and respectively the Abelian-Higgs vortex models.Comment: Latex 126 pages, 7 eps figures included. Discussion on various forms of the equatio

    Spanning tree generating functions and Mahler measures

    Full text link
    We define the notion of a spanning tree generating function (STGF) anzn\sum a_n z^n, which gives the spanning tree constant when evaluated at z=1,z=1, and gives the lattice Green function (LGF) when differentiated. By making use of known results for logarithmic Mahler measures of certain Laurent polynomials, and proving new results, we express the STGFs as hypergeometric functions for all regular two and three dimensional lattices (and one higher-dimensional lattice). This gives closed form expressions for the spanning tree constants for all such lattices, which were previously largely unknown in all but one three-dimensional case. We show for all lattices that these can also be represented as Dirichlet LL-series. Making the connection between spanning tree generating functions and lattice Green functions produces integral identities and hypergeometric connections, some of which appear to be new.Comment: 26 pages. Dedicated to F Y Wu on the occasion of his 80th birthday. This version has additional references, additional calculations, and minor correction

    Optimal interlayer hopping and high temperature Bose–Einstein condensation of local pairs in quasi 2D superconductors

    Get PDF
    Both FeSe and cuprate superconductors are quasi 2D materials with high transition temperatures and local fermion pairs. Motivated by such systems, we investigate real space pairing of fermions in an anisotropic lattice model with intersite attraction, V, and strong local Coulomb repulsion, U, leading to a determination of the optimal conditions for superconductivity from Bose–Einstein condensation. Our aim is to gain insight as to why high temperature superconductors tend to be quasi 2D. We make both analytically and numerically exact solutions for two body local pairing applicable to intermediate and strong V. We find that the Bose–Einstein condensation temperature of such local pairs pairs is maximal when hopping between layers is intermediate relative to in-plane hopping, indicating that the quasi 2D nature of unconventional superconductors has an important contribution to their high transition temperatures

    Unusual nanostructures of "lattice matched" InP on AlInAs

    Get PDF
    We show that the morphology of the initial monolayers of InP on Al0.48In0.52As grown by metalorganic vapor-phase epitaxy does not follow the expected layer-by-layer growth mode of lattice-matched systems, but instead develops a number of low-dimensional structures, e.g., quantum dots and wires. We discuss how the macroscopically strain-free heteroepitaxy might be strongly affected by local phase separation/alloying-induced strain and that the preferred aggregation of adatom species on the substrate surface and reduced wettability of InP on AlInAs surfaces might be the cause of the unusual (step) organization and morpholog

    On induced CPT-odd Chern-Simons terms in 3+1 effective action

    Full text link
    This paper was originally designated as Comment to the paper by R. Jackiw and V. Alan Kostelecky (hep-ph/9901358). We provide an example of the fermionic system, the superfluid 3He-A, in which the CPT-odd Chern-Simons terms in the effective action are unambiguously induced by chiral fermions. In this system the Lorentz and gauge invariances both are violated at high energy, but the behavior of the system beyond the cut-off is known. This allows us to construct the CPT-odd action, which combines the conventional 3+1 Chern-Simons term and the mixed axial-gravitational Chern-Simons term discussed in hep-ph/9905460. The influence of Chern-Simons term on the dynamics of the effective gauge field has been experimentally observed in rotating 3He-A.Comment: RevTex, 3 pages, no figures, extended version of Comment to the paper by R. Jackiw and V. Alan Kostelecky (hep-ph/9901358), to appear in JETP Let

    Primordial Magnetic Fields, Right Electrons, and the Abelian Anomaly

    Get PDF
    In the standard model there are charges with abelian anomaly only (e.g. right-handed electron number) which are effectively conserved in the early universe until some time shortly before the electroweak scale. A state at finite chemical potential of such a charge, possibly arising due to asymmetries produced at the GUT scale, is unstable to the generation of hypercharge magnetic field. Quite large magnetic fields (1022\sim 10^{22} gauss at T100T\sim 100 GeV with typical inhomogeneity scale 106T \sim \frac{ 10^6}{T}) can be generated. These fields may be of cosmological interest, potentially acting as seeds for amplification to larger scale magnetic fields through non-linear mechanisms. Previously derived bounds on exotic BLB-L violating operators may also be evaded.Comment: Revised version, to appear in Phys. Rev. Lett.. Analysis has been extended to larger chemical potentials, for which large magnetic fields survive at the electroweak scale. Previous bounds on BLB-L violating operators are also evaded in this cas

    Electroweak baryogenesis induced by a scalar field

    Get PDF
    A cosmological pseudoscalar field coupled to hypercharge topological number density can exponentially amplify hyperelectric and hypermagnetic fields while coherently rolling or oscillating, leading to the formation of a time-dependent condensate of topological number density. The topological condensate can be converted, under certain conditions, into baryons in sufficient quantity to explain the observed baryon asymmetry in the universe. The amplified hypermagnetic field can perhaps sufficiently strengthen the electroweak phase transition, and by doing so, save any pre-existing baryon number asymmetry from extinction.Comment: 8 pages, 4 figure

    Statistics of nested spiral self-avoiding loops: exact results on the square and triangular lattices

    Full text link
    The statistics of nested spiral self-avoiding loops, which is closely related to the partition of integers into decreasing parts, is studied on the square and triangular lattices.Comment: Old paper, for archiving. 7 pages, 2 figures, epsf, IOP macr

    Orotracheal intubation in infants performed with a stylet versus without a stylet

    Get PDF
    Background: Neonatal endotracheal intubation is a common and potentially life-saving intervention. It is a mandatory skill for neonatal trainees, but one that is difficult to master and maintain. Intubation opportunities for trainees are decreasing and success rates are subsequently falling. Use of a stylet may aid intubation and improve success. However, the potential for associated harm must be considered. Objectives To compare the benefits and harms of neonatal orotracheal intubation with a stylet versus neonatal orotracheal intubation without a stylet. Search methods: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library; MEDLINE; Embase; the Cumulative Index to Nursing and Allied Health Literature (CINAHL), and previous reviews. We also searched cross-references, contacted expert informants, handsearched journals, and looked at conference proceedings. We searched clinical trials registries for current and recently completed trials. We conducted our most recent search in April 2017. Selection criteria All randomised, quasi–randomised, and cluster-randomised controlled trials comparing use versus non-use of a stylet in neonatal orotracheal intubation. Data collection and analysis: Two review authors independently assessed results of searches against predetermined criteria for inclusion, assessed risk of bias, and extracted data. We used the standard methods of the Cochrane Collaboration, as documented in the Cochrane Handbook for Systemic Reviews of Interventions, and of the Cochrane Neonatal Review Group. Main results: We included a single-centre non-blinded randomised controlled trial that reported a total of 302 intubation attempts in 232 infants. The median gestational age of enrolled infants was 29 weeks. Paediatric residents and fellows performed the intubations. We judged the study to be at low risk of bias overall. Investigators compared success rates of first-attempt intubation with and without use of a stylet and reported success rates as similar between stylet and no-stylet groups (57% and 53%) (P = 0.47). Success rates did not differ between groups in subgroup analyses by provider level of training and infant weight. Results showed no differences in secondary review outcomes, including duration of intubation, number of attempts, participant instability during the procedure, and local airway trauma. Only 25% of all intubations took less than 30 seconds to perform. Study authors did not report neonatal morbidity nor mortality. We considered the quality of evidence as low on GRADE analysis, given that we identified only one unblinded study. Authors' conclusions: Current available evidence suggests that use of a stylet during neonatal orotracheal intubation does not significantly improve the success rate among paediatric trainees. However, only one brand of stylet and one brand of endotracheal tube have been tested, and researchers performed all intubations on infants in a hospital setting. Therefore, our results cannot be generalised beyond these limitations
    corecore