132 research outputs found

    Speciation via Autoimmunity: A Dangerous Mix

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    In this issue of Cell, Chae et al. find that genomic “hot spots” encoding NLR plant immune receptor genes are recurrently responsible for hybrid necrosis, highlighting the role of host-pathogen evolutionary arms races in driving the evolution of hybrid incompatibilities

    Sugarcane trash chopper cum spreader-A viable machine to avoid trash burning

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    Trash burning is a major problem in sugarcane to overcome this, a sugarcane trash chopper cum spreader was tested at farmer’s field for its performance and economic feasibility. The chopper cum spreader was tested at five levels of moisture content of trash (13.2, 14, 15.15, 16.6, and 18.8% db) and five levels of operationalspeed (2.6, 2.8, 2.9, 3.1, and 3.4 km/h). The performance of the sugarcane trash chopper cum spreader heavily depends on moisture content and speed of operation. The maximum field capacity (0.43ha/h) was obtained at a speed of 3.2 km/h, but maximum shredding efficiency (90.40%) was found at a speed of 2.9 km/h. Maximumuniformity coefficient (0.95) and shredding capacity (4.31 t/h) was obtained at a speed of 2.9 km/h and at a moisture content of 13.13%. Maximum trash lifting efficiency (93.95%) was observed at a speed of 2.76 km/h and at a moisture content of 13.13%. The cost of operation was Rs. 2015/ha with B: C ratio of 1.5. The break-even point ofthe chopper cum spreader was 17.7 ha and payback of the machine was 1.3 years if operated for 250 h/year. The energy consumption of machine was calculated to be 1327.7 MJ ha-1. The optimum performance of sugarcane trash chopper cum spreader was obtained at a moisture content of 13.13% (M5) and forward speed of 2.9 km h-1 (V3). The sugarcane trash chopper cum spreader may be recommended for chopping of sugarcane trash for mulching to avoid burning of trash and conserving natural resources

    Large and uniform optical emission shifts in quantum dots externally strained along their growth axis

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    We introduce a method which enables to directly compare the impact of elastic strain on the optical properties of distinct quantum dots (QDs). Specifically, the QDs are integrated in a cross-section of a semiconductor core wire which is surrounded by an amorphous straining shell. Detailed numerical simulations show that, thanks to the mechanical isotropy of the shell, the strain field in a core section is homogeneous. Furthermore, we use the core material as an in situ strain gauge, yielding reliable values for the emitter energy tuning slope. This calibration technique is applied to self-assembled InAs QDs submitted to incremental tensile strain along their growth axis. In contrast to recent studies conducted on similar QDs stressed perpendicularly to their growth axis, optical spectroscopy reveals 5-10 times larger tuning slopes, with a moderate dispersion. These results highlight the importance of the stress direction to optimise QD response to applied strain, with implications both in static and dynamic regimes. As such, they are in particular relevant for the development of wavelength-tunable single photon sources or hybrid QD opto-mechanical systems

    Dielectric GaAs Antenna Ensuring an Efficient Broadband Coupling between an InAs Quantum Dot and a Gaussian Optical Beam

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    We introduce the photonic trumpet, a dielectric structure which ensures a nearly perfect coupling between an embedded quantum light source and a Gaussian free-space beam. A photonic trumpet exploits both the broadband spontaneous emission control provided by a single-mode photonic wire and the adiabatic expansion of this mode within a conical taper. Numerical simulations highlight the outstanding performance and robustness of this concept. As a first application in the field of quantum optics, we report the realisation of an ultra-bright single-photon source. The device, a GaAs photonic trumpet containing few InAs quantum dots, demonstrates a first-lens external efficiency of 0.75±0.10.75 \pm 0.1

    Genetic parameters for milk, fat and protein yields in Murrah buffaloes (Bubalus bubalis Artiodactyla, Bovidae)

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    The objective of the present study was to estimate genetic parameters for test-day milk, fat and protein yields and 305-day-yields in Murrah buffaloes. 4,757 complete lactations of Murrah buffaloes were analyzed. Co-variance components were estimated by the restricted maximum likelihood method. The models included additive direct genetic and permanent environmental effects as random effects, and the fixed effects of contemporary group, milking number and age of the cow at calving as linear and quadratic covariables. Contemporary groups were defined by herd-year-month of test for test-day yields and by herd-year-season of calving for 305-day yields. The heritability estimates obtained by two-trait analysis ranged from 0.15 to 0.24 for milk, 0.16 to 0.23 for protein and 0.13 to 0.22 for fat, yields. Genetic and phenotypic correlations were all positive. The observed population additive genetic variation indicated that selection might be an effective tool in changing population means in milk, fat and protein yields

    Uklanjanje obostranog dermoida na bulbarnoj spojnici šteneta pasmine labrador retriver elektrokauterom - prikaz slučaja.

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    A Labrador retriever pup with a bilateral dermoid in the eyes was treated successfully by the use of a unipolar hand held electrocautery unit.Štene pasmine labrador retriver s obostranim dermoidom u očima bilo je uspješno izliječeno upotrebom jednostranog ručnog elektrokautera
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