696 research outputs found
Piloting a commercial broiler production model for smallholders in Rwanda
Increasing food security is premised on improving economic empowerment as well as nutrition across the household. As such, developmentprojects across Africa are integrating nutrition objectives into pro-poor value chain development interventions toincrease dietary diversity and incomes. To meet the micronutrient demands of a growingpopulation, Rwanda seeks to increase the production of and access to meat-basedproteins, including chicken production. Despite Rwanda’s recent rapid economic growth,there is a limited supply of and access to animal-sourced protein nationally. A hybridbroiler model, which integrates elements of smallholder and larger intensive poultrymodels, could be a sustainable approach. A model piloted in Musanze District, Rwanda.Tworore Inkoko, Twunguke (TI) (Let’s raise chickens for profit!) uses an intensive, 100-bird model with the aim of training and supporting 750 smallholder farmers through aninnovative private-sector-based train-the-trainer approach. This study examines the initial evidence from TI production data to determine (a) the performance of improved broiler breeds in a Rwandan smallholder context, (b) farmer profitability, and (c) household consumption of broilers. With 18 months of flock data, average livability of flocks was 89%, similar to large-scale, modern broiler sector averages globally. Tworore Inkoko smallholders have been profitable, with average profit increasing as they gain experience and grow-out new flocks (profit ranging between 28 and 89 USD per flock). Birds set aside for consumption by farmers ranged from an average of 0.31 to 4.00 birds per flock, settling at closer to three per flock by the end of the first 18 months. Smallholder farmers in Rwanda have the potential to be successful through this model. Lessons learned from the rollout of this pilot project will be used to inform potential scale-up of this hybrid model across Rwanda, as well as other pro-poor value chains looking to increase food security by generating incomes and increasing access to highly nutritious and balanced diets. 
d=2, N=2 Superconformal Symmetries and Models
We discuss the following aspects of two-dimensional N=2 supersymmetric
theories defined on compact super Riemann surfaces: parametrization of (2,0)
and (2,2) superconformal structures in terms of Beltrami coefficients and
formulation of superconformal models on such surfaces (invariant actions,
anomalies and compensating actions, Ward identities).Comment: 43 pages, late
Determinants of methicillin-susceptible Staphylococcus aureus native bone and joint infection treatment failure: a retrospective cohort study.
BACKGROUND: Although methicillin-susceptible Staphylococcus aureus (MSSA) native bone and joint infection (BJI) constitutes the more frequent clinical entity of BJI, prognostic studies mostly focused on methicillin-resistant S. aureus prosthetic joint infection. We aimed to assess the determinants of native MSSA BJI outcomes.
METHODS: Retrospective cohort study (2001-2011) of patients admitted in a reference hospital centre for native MSSA BJI. Treatment failure determinants were assessed using Kaplan-Meier curves and binary logistic regression.
RESULTS: Sixty-six patients (42 males [63.6%]; median age 61.2 years; interquartile range [IQR] 45.9-71.9) presented an acute (n = 38; 57.6%) or chronic (n = 28; 42.4%) native MSSA arthritis (n = 15; 22.7%), osteomyelitis (n = 19; 28.8%) or spondylodiscitis (n = 32; 48.5%), considered as "difficult-to-treat" in 61 cases (92.4%). All received a prolonged (27.1 weeks; IQR, 16.9-36.1) combined antimicrobial therapy, after surgical management in 37 cases (56.1%). Sixteen treatment failures (24.2%) were observed during a median follow-up period of 63.3 weeks (IQR, 44.7-103.1), including 13 persisting infections, 1 relapse after treatment disruption, and 2 super-infections. Independent determinants of treatment failure were the existence of a sinus tract (odds ratio [OR], 5.300; 95% confidence interval [CI], 1.166-24.103) and a prolonged delay to infectious disease specialist referral (OR, 1.134; 95% CI 1.013-1.271).
CONCLUSIONS: The important treatment failure rate pinpointed the difficulty of cure encountered in complicated native MSSA BJI. An early infectious disease specialist referral is essential, especially in debilitated patients or in presence of sinus tract
Morpho-Rheological Fingerprinting of Rod Photoreceptors Using Real-Time Deformability Cytometry
Distinct cell-types within the retina are mainly specified by morphological and molecular parameters, however, physical properties are increasingly recognized as a valuable tool to characterize and distinguish cells in diverse tissues. High-throughput analysis of morpho-rheological features has recently been introduced using real-time deformability cytometry (RT-DC) providing new insights into the properties of different cell-types. Rod photoreceptors represent the main light sensing cells in the mouse retina that during development forms apically the densely packed outer nuclear layer. Currently, enrichment and isolation of photoreceptors from retinal primary tissue or pluripotent stem cell-derived organoids for analysis, molecular profiling, or transplantation is achieved using flow cytometry or magnetic activated cell sorting approaches. However, such purification methods require genetic modification or identification of cell surface binding antibody panels. Using primary retina and embryonic stem cell-derived retinal organoids, we characterized the inherent morpho-mechanical properties of mouse rod photoreceptors during development based on RT-DC. We demonstrate that rods become smaller and more compliant throughout development and that these features are suitable to distinguish rods within heterogenous retinal tissues. Hence, physical properties should be considered as additional factors that might affect photoreceptor differentiation and retinal development besides representing potential parameters for label-free sorting of photoreceptors
Supersymmetric structure of the induced W gravities
We derive the supersymmetric structure present in W-gravities which has been
already observed in various contexts as Yang-Mills theory, topological field
theories, bosonic string and chiral W_{3}-gravity. This derivation which is
made in the geometrical framework of Zucchini, necessitates the introduction of
an appropriate new basis of variables which replace the canonical fields and
their derivatives. This construction is used, in the W_{2}-case, to deduce from
the Chern-Simons action the Wess-Zumino-Polyakov action.Comment: 17 pages, Latex. To appear in Class. Quantum. Gravit
Label-free imaging flow cytometry for analysis and sorting of enzymatically dissociated tissues
Biomedical research relies on identification and isolation of specific cell types using molecular biomarkers and sorting methods such as fluorescence or magnetic activated cell sorting. Labelling processes potentially alter the cells’ properties and should be avoided, especially when purifying cells for clinical applications. A promising alternative is the label-free identification of cells based on physical properties. Sorting real-time deformability cytometry (soRT-DC) is a microfluidic technique for label-free analysis and sorting of single cells. In soRT-FDC, bright-field images of cells are analyzed by a deep neural net (DNN) to obtain a sorting decision, but sorting was so far only demonstrated for blood cells which show clear morphological differences and are naturally in suspension. Most cells, however, grow in tissues, requiring dissociation before cell sorting which is associated with challenges including changes in morphology, or presence of aggregates. Here, we introduce methods to improve robustness of analysis and sorting of single cells from nervous tissue and provide DNNs which can distinguish visually similar cells. We employ the DNN for image-based sorting to enrich photoreceptor cells from dissociated retina for transplantation into the mouse eye
Search for Flavoured Multiquarks in a Simple Bag Model
We use a bag model to study flavoured mesonic and baryonic
states, where one heavy quark is associated with
light quarks or antiquarks, and search for possible stable multiquarks. No
bound state is found. However some states lie not too high above their
dissociation threshold, suggesting the possibility of resonances, or perhaps
bound states in improved models.Comment: REVTEX, VERSION 3.
Zero temperature phases of the frustrated J1-J2 antiferromagnetic spin-1/2 Heisenberg model on a simple cubic lattice
At zero temperature magnetic phases of the quantum spin-1/2 Heisenberg
antiferromagnet on a simple cubic lattice with competing first and second
neighbor exchanges (J1 and J2) is investigated using the non-linear spin wave
theory. We find existence of two phases: a two sublattice Neel phase for small
J2 (AF), and a collinear antiferromagnetic phase at large J2 (CAF). We obtain
the sublattice magnetizations and ground state energies for the two phases and
find that there exists a first order phase transition from the AF-phase to the
CAF-phase at the critical transition point, pc = 0.28. Our results for the
value of pc are in excellent agreement with results from Monte-Carlo
simulations and variational spin wave theory. We also show that the quartic 1/S
corrections due spin-wave interactions enhance the sublattice magnetization in
both the phases which causes the intermediate paramagnetic phase predicted from
linear spin wave theory to disappear.Comment: 19 pages, 4 figures, Fig. 1b modified, Appendix B text modifie
Does A Narrow Tetraquark State Exist?
The existence of a shallow or virtual tetraquark state, ,
is discussed. Using the putative masses for the doubly charmed baryons
() from SELEX, the mass of the state is estimated
to be about , only slightly above the threshold. The
experimental signatures for various masses are also
discussed.Comment: LaTeX, 16 page
Research on Layer Manufacturing Techniques at Fraunhofer
Within the German Fraunhofer-Gesellschaft, the Fraunhofer Alliance Rapid Prototyping
unites the competences of 12 institutes in the field of solid freeform fabrication. Covered
competences are virtual and computer-aided product planning methods and techniques, the
development and integration of materials and processes for different industrial sectors. This
paper presents actual research results on layer manufacturing within the Fraunhofer-
Gesellschaft based on examples from Fraunhofer ILT »Laser Melting - Direct
manufacturing of metal parts with unique properties«, Fraunhofer IFAM »ecoMold - A
novel concept to produce molds for plastic injection molding and pressure die casting« and
Fraunhofer IPT »Quick manufacture, repair and modification of steel molds using
Controlled Metal Build Up (CMB)«.Mechanical Engineerin
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