46 research outputs found
An experimental study to discriminate between the validity of diffraction theories for off-Bragg replay
We show that experiments clearly verify the assumptions made by the
first-order two-wave coupling theory for one dimensional lossless unslanted
planar volume holographic gratings using the beta-value method rather than
Kogelnik's K-vector closure method. Apart from the fact that the diffraction
process is elastic, a much more striking difference between the theories
becomes apparent particularly in the direction of the diffracted beam in
off-Bragg replay. We therefore monitored the direction of the diffracted beam
as a function of the off-Bragg replay angle in two distinct cases: [a] the
diffracted beam lies in the plane of incidence and [b] the sample surface
normal, the grating vector and the incoming beam do not form a plane which
calls for the vectorial theory and results in conical scattering.Comment: Corrected Eqs. (3) & (6); 14 pages, 8 figure
Learning Object Repositories with Federated Searcher over the Cloud
The education sector is a significant generator, consumer and depository for educational content. Educators and Learners have access to technologies that allow them to obtain information ubiquitously on demand. The problems arising from the integration of educational content are usually caused by the vast amount of educational content distributed among several repositories. This work presents a proposal for an architecture based on a cloud computing paradigm that will permit the evolution of current learning resource repositories by means of cloud computing paradigm and the integration of federated search system
First Observation of the Cabibbo-suppressed Decays Xi_c+ -> Sigma+ pi- pi+ and Xi_c+ -> Sigma- pi+ pi+ and Measurement of their Branching Ratios
We report the first observation of two Cabibbo-suppressed decay modes, Xi_c+
-> Sigma+ pi- pi+ and Xi_c+ -> Sigma- pi+ pi+. We observe 59+/-14 over a
background of 87, and 22+/-8 over a background of 13 events, respectively, for
the signals. The data were accumulated using the SELEX spectrometer during the
1996-1997 fixed target run at Fermilab, chiefly from a 600GeV/c Sigma- beam.
The branching ratios of the decays relative to the Cabibbo--favored Xi_c+ ->
Xi- pi+ pi+ are measured to be B(Xi_c+ -> Sigma+ pi- pi+)/B(Xi_c+ -> Xi- pi+
pi+) = 0.48+/-0.20, and B(Xi_c+ -> Sigma- pi+ pi+)/B(Xi_c+ -> Xi- pi+ pi+) =
0.18+/-0.09, respectively. We also report branching ratios for the same decay
modes of the Lambda_c+ relative to Lambda_c+ -> p K- pi+.Comment: 15 pages, 5 figures, version 2 as accepted in PL
Distribuição de potåssio em gotejamento com fertirrigação em diferentes pontos de injeção na linha principal
[EN] The purpose of this research was to evaluate the K2O distribution uniformity by surface drip irrigation at Universitat Politecnica de Valencia, Valencia, Spain (39Âș 29âČ N, 0Âș 23âČ W, 20 m). The irrigation was performed by drip lines with not-compensated emitters, spaced 0.3 m. The fertigation was realized using a fertilizer injector pump of electric action with injection of 0.25 h. The experimental design used completely randomized blocks with five treatments and four replications. The treatments consisted of injection in five distances, located at 10; 20; 30; 40; 50 m of the first drip line. Samples were collected in emitters located at the start, at 1/3, at 2/3 and at the end of the drip lines. The nutrient concentration was determined by flame spectrophotometry. The Christiansen's uniformity coefficients (CUC), of distribution (DUC), of statistical (SUC) and of emission (eUC) were estimated. The K2O concentration and distribution decreased linearly with the increase of the injection distance. In all treatments, the CUC, SUC and DUC were described as 'excellent'. The eUC was described as 'recommended' only at smaller injection distances.[PT] Objetivando fornecer subsĂdios para os produtores aperfeiçoarem o manejo da
fertirrigação em pequenas ĂĄreas, avaliou-se, na Universitat PolitĂšcnica de ValĂšncia, ValĂȘncia,
Espanha (39° 29âČ N, 0° 23âČ W, 20 m), a uniformidade de distribuição do K2O via irrigação por
gotejamento superficial em função da distùncia do ponto de injeção na linha principal. A irrigação
foi efetuada por linhas laterais com emissores não compensantes, espaçados de 0,3 m. Na
fertirrigação, foi utilizada uma bomba injetora de fertilizante de acionamento elétrico, com o tempo
de injeção de 0,25 h. O delineamento experimental foi o de blocos casualizados, com cinco
tratamentos e quatro repetiçÔes. Os tratamentos consistiram em cinco pontos de injeção na linha
principal, situados a: 10; 20; 30; 40 e 50 m da primeira linha lateral. Foram coletadas amostras em
emissores localizados no inĂcio, a 1/3, a 2/3 e no final das linhas laterais. A concentração do
nutriente foi determinada por espectrofotometria de chama. Foram estimados os coeficientes de
uniformidade de Christiansen (CUC), de distribuição (CUD), estatĂstico (CUE) e de emissĂŁo (CUe).
A concentração e a distribuição de K2O diminuĂram linearmente com o aumento da distĂąncia do
ponto de injeção. Em todos os tratamentos, o CUC, CUE e CUD foram classificados como
âexcelenteâ. O CUe foi classificado como ârecomendadoâ apenas na menor distĂąncia de injeção.To the Coordination of Improvement of Higher Education Personnel (CAPES) for grant the Doctoral Sandwich Abroad scholarship and the Universitat PolitĂšcnica de ValĂšncia (UPV), for providing the experimental area and all equipment and supplies needed for the research.Do Bomfim, GV.; Manzano Juarez, J.; De Azevedo, BM.; Vasconcelos, DV.; Viana, TVDA. (2014). Potassium distribution in drip irrigation with fertigation for different injection distances in the main line. Engenharia AgrĂcola. 34(6):1151-1161. doi:10.1590/S0100-69162014000600011S1151116134
Search for dark matter produced in association with a hadronically decaying vector boson in pp collisions at sqrt (s) = 13 TeV with the ATLAS detector
A search is presented for dark matter produced in association with a hadronically decaying W or Z boson using 3.2 fbâ1 of pp collisions at View the MathML sources=13 TeV recorded by the ATLAS detector at the Large Hadron Collider. Events with a hadronic jet compatible with a W or Z boson and with large missing transverse momentum are analysed. The data are consistent with the Standard Model predictions and are interpreted in terms of both an effective field theory and a simplified model containing dark matter
EPIdemiology of Surgery-Associated Acute Kidney Injury (EPIS-AKI) : Study protocol for a multicentre, observational trial
More than 300 million surgical procedures are performed each year. Acute kidney injury (AKI) is a common complication after major surgery and is associated with adverse short-term and long-term outcomes. However, there is a large variation in the incidence of reported AKI rates. The establishment of an accurate epidemiology of surgery-associated AKI is important for healthcare policy, quality initiatives, clinical trials, as well as for improving guidelines. The objective of the Epidemiology of Surgery-associated Acute Kidney Injury (EPIS-AKI) trial is to prospectively evaluate the epidemiology of AKI after major surgery using the latest Kidney Disease: Improving Global Outcomes (KDIGO) consensus definition of AKI. EPIS-AKI is an international prospective, observational, multicentre cohort study including 10 000 patients undergoing major surgery who are subsequently admitted to the ICU or a similar high dependency unit. The primary endpoint is the incidence of AKI within 72 hours after surgery according to the KDIGO criteria. Secondary endpoints include use of renal replacement therapy (RRT), mortality during ICU and hospital stay, length of ICU and hospital stay and major adverse kidney events (combined endpoint consisting of persistent renal dysfunction, RRT and mortality) at day 90. Further, we will evaluate preoperative and intraoperative risk factors affecting the incidence of postoperative AKI. In an add-on analysis, we will assess urinary biomarkers for early detection of AKI. EPIS-AKI has been approved by the leading Ethics Committee of the Medical Council North Rhine-Westphalia, of the Westphalian Wilhelms-University MĂŒnster and the corresponding Ethics Committee at each participating site. Results will be disseminated widely and published in peer-reviewed journals, presented at conferences and used to design further AKI-related trials. Trial registration number NCT04165369