Algunos aspectos sobre la biologia, ecologia, dano economico y control de Chilomina clarkei (Amsel) (Lepidoptera, Pyralidae) barrenador de la yuca

The biology, behavior, ecology, economic damage, and control of the cassava stemborer Chilomina clarkei are described. Its natural enemies found are listed: Agathis sp., Bracon sp., Apanteles sp., Brachymeria sp., and Trichogramma sp. The economic damage in artificial infestations with 2 levels of attack (8-12 and 16-20 larvae/plant) and a treatment of simulated damage breaking stems at 5 mo. were studied. A significant reduction in root yield (62, 45, and 46 percent, resp.) percentage of commercial roots, no. of broken stems, and the no, of cuttings/plant was found. (CIAT)Se describen la biologia, el comportamiento, la ecologia, el dano economico y el control de Chilomina clarkei barrenador de la yuca. Se enumeran sus enemigos naturales encontrados: Agathis sp., Bracon sp., Apanteles sp., Brachymeria sp., y Trichogramma sp. Se estudiaron el dano economico en infestaciones artificiales con 2 niveles de ataque (8-12 y 16-20 larvas/planta) y un tratamiento de dano simulado partiendo los tallos a los 5 meses. Se encontro una reduccion significativa en el rendimiento de raices (62, 45 y 46 por ciento, resp.), el porcentaje de raices comerciales, el no. de tallos partidos y el no. de estacas/planta. (CIAT

Flux through a hole from a shaken granular medium

We have measured the flux of grains from a hole in the bottom of a shaken container of grains. We find that the peak velocity of the vibration, vmax, controls the flux, i.e., the flux is nearly independent of the frequency and acceleration amplitude for a given value of vmax. The flux decreases with increasing peak velocity and then becomes almost constant for the largest values of vmax. The data at low peak velocity can be quantitatively described by a simple model, but the crossover to nearly constant flux at larger peak velocity suggests a regime in which the granular density near the container bottom is independent of the energy input to the system.Comment: 14 pages, 4 figures. to appear in Physical Review

Stress reducing effects of real and artificial nature in a hospital waiting room

Objectives: This field study investigated the potential stress-reducing effects of exposure to real or artificial nature on patients in a hospital waiting room. Additionally, it was investigated whether perceived attractiveness of the room could explain these effects. Design: In this between-patients experimental design, patients were exposed to one of the following: real plants, posters of plants, or no nature (control). These conditions were alternately applied to two waiting rooms. Location: The location of this study was two waiting rooms at the Radiology Department of a Dutch hospital. Subjects: The subjects comprised 457 patients (60% female and 40% male) who were mostly scheduled for echocardiogram, dual-energy x-ray absorptiometry, magnetic resonance imaging, computed tomography scans, or nuclear research. Results: Patients exposed to real plants, as well as patients exposed to posters of plants, report lower levels of experienced stress compared to the control condition. Further analyses show that these small but significant effects of exposure to nature are partially mediated by the perceived attractiveness of the waiting room. Conclusions: Natural elements in hospital environments have the potential to reduce patients' feelings of stress. By increasing the attractiveness of the waiting room by adding either real plants or posters of plants, hospitals can create a pleasant atmosphere that positively influences patients' well-being

Organische Dünger in Topfkulturen auf dem Prüfstand - wie steht es mit der Stickstofffreisetzung?

Matching nitrogen demand of plants and N release of organic fertilizers with respect to amount and timing is one key for successful cultivation of organic ornamentals. Thereby for plants with a low to moderate N demand growers can add the fertilizer as complete preplant application (CPA). For plants with a high N demand splitting fertilization in a reduced preplant application combined with an additional fertigation (RPA+F) is preferable. Aim of the current research was the investigation of N release of organic fertilizers in incubation experiments. Results of the incubation experiment were linked to a pot trial with pelargonium. Incubation experiments reveal that most fertilizers release about 40 to 50 % of total N and most nitrogen is released within the first 21 days. Only for sheep wool a delay of N release up to ten days was found. CPA using sheep wool and RPA+F (irrespective of fertilizer) give the best results. The delayed release pattern of sheep wool seems to match best N demand of plants

Decision and function problems based on boson sampling

Boson sampling is a mathematical problem that is strongly believed to be intractable for classical computers, whereas passive linear interferometers can produce samples efficiently. So far, the problem remains a computational curiosity, and the possible usefulness of boson-sampling devices is mainly limited to the proof of quantum supremacy. The purpose of this work is to investigate whether boson sampling can be used as a resource of decision and function problems that are computationally hard, and may thus have cryptographic applications. After the definition of a rather general theoretical framework for the design of such problems, we discuss their solution by means of a brute-force numerical approach, as well as by means of non-boson samplers. Moreover, we estimate the sample sizes required for their solution by passive linear interferometers, and it is shown that they are independent of the size of the Hilbert space.Comment: Close to the version published in PR

A VLT/FLAMES survey for massive binaries in Westerlund 1. V. the X-ray selected blue stragglers Wd1-27 and -30a

Context. Recent observational studies indicate that a large number of OB stars are found within binary systems which may be expected to interact during their lifetimes. Significant mass transfer or indeed merger of both components is expected to modify evolutionary pathways, facilitating the production of exceptionally massive stars which will present as blue stragglers. Identification and characterisation of such objects is crucial if the efficiency of mass transfer is to be established; a critical parameter in determining the outcomes of binary evolutionary channels. Aims. The young and coeval massive cluster Westerlund 1 hosts a rich population of X-ray bright OB and Wolf-Rayet stars where the emission is attributed to shocks in the wind collision zones of massive binaries. Motivated by this, we instigated a study of the extremely X-ray luminous O supergiants Wd1-27 and -30a. Methods. We subjected a multi-wavelength and -epoch photometric and spectroscopic dataset to quantitative non-LTE model atmosphere and time-series analysis in order to determine fundamental stellar parameters and search for evidence of binarity. A detailed examination of the second Gaia data release was undertaken to establish cluster membership. Results. Both stars were found to be early/mid-O hypergiants with luminosities, temperatures and masses significantly in excess of other early stars within Wd1, hence qualifying as massive blue stragglers. The binary nature of Wd1-27 remains uncertain but the detection of radial velocity changes and the X-ray properties of Wd1-30a suggest that it is a binary with an orbital period ≤ 10 days. Analysis of Gaia proper motion and parallactic data indicates that both stars are cluster members; we also provide a membership list for Wd1 based on this analysis. Conclusions. The presence of hypergiants of spectral types O to M within Wd1 cannot be understood solely via single-star evolution. We suppose that the early-B and mid-O hypergiants formed via binary-induced mass-stripping of the primary and mass-transfer to the secondary, respectively. This implies that for a subset of objects massive star-formation may be regarded as a two-stage process, with binary-driven mass-transfer or merger yielding stars with masses significantly in excess of their initial ‘birth’ mass

Correspondence on rajyaguru et al

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Evaluation of critical congenital heart defects screening using pulse oximetry in the neonatal intensive care unit.

ObjectiveTo evaluate the implementation of early screening for critical congenital heart defects (CCHDs) in the neonatal intensive care unit (NICU) and potential exclusion of sub-populations from universal screening.Study designProspective evaluation of CCHD screening at multiple time intervals was conducted in 21 NICUs across five states (n=4556 infants).ResultsOf the 4120 infants with complete screens, 92% did not have prenatal CHD diagnosis or echocardiography before screening, 72% were not receiving oxygen at 24 to 48 h and 56% were born ⩾2500 g. Thirty-seven infants failed screening (0.9%); none with an unsuspected CCHD. False positive rates were low for infants not receiving oxygen (0.5%) and those screened after weaning (0.6%), yet higher among infants born at <28 weeks (3.8%). Unnecessary echocardiograms were minimal (0.2%).ConclusionGiven the majority of NICU infants were ⩾2500 g, not on oxygen and not preidentified for CCHD, systematic screening at 24 to 48 h may be of benefit for early detection of CCHD with minimal burden

High-harmonic generation from a confined atom

The order of high harmonics emitted by an atom in an intense laser field is limited by the so-called cutoff frequency. Solving the time-dependent Schr\"odinger equation, we show that this frequency can be increased considerably by a parabolic confining potential, if the confinement parameters are suitably chosen. Furthermore, due to confinement, the radiation intensity remains high throughout the extended emission range. All features observed can be explained with classical arguments.Comment: 4 pages(tex files), 4 figures(eps files); added references and comment