Low Energy Light Yield of Fast Plastic Scintillators

Compact neutron imagers using double-scatter kinematic reconstruction are being designed for localization and characterization of special nuclear material. These neutron imaging systems rely on scintillators with a rapid prompt temporal response as the detection medium. As n-p elastic scattering is the primary mechanism for light generation by fast neutron interactions in organic scintillators, proton light yield data are needed for accurate assessment of scintillator performance. The proton light yield of a series of commercial fast plastic organic scintillators---EJ-200, EJ-204, and EJ-208---was measured via a double time-of-flight technique at the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory. Using a tunable deuteron breakup neutron source, target scintillators housed in a dual photomultiplier tube configuration, and an array of pulse-shape-discriminating observation scintillators, the fast plastic scintillator light yield was measured over a broad and continuous energy range down to proton recoil energies of approximately 50 keV. This work provides key input to event reconstruction algorithms required for utilization of these materials in emerging neutron imaging modalities.Comment: 15 pages, 6 figure

Периоперационная эволюция фенотипа хронической сердечной недостаточности у кардиохи- рургических больных.

Background. Heart failure (HF) is a well-defined risk factor for early mortality and morbidity after cardiac surgery.We aimed to analyze the evolution of the clinical phenotype of HF at an early stage after heart surgery.Methods. The study included 126 consecutive patients with established chronic HF who fulfilled the cardiac rehabilitation program after undergoing heart surgery (62.23±8.59 years, 67.5% - men). Subjects were divided into 3 groups according to the clinical phenotype of HF: group 1 - HF with reduced left ventricular (LV) ejection fraction (EF) (HFrEF), group 2 - HF with mildly reduced LV EF (HFmrEF) and group 3 - HF with preserved LV EF (HFpEF). All patients were investigated by electrocardiography, transthoracic echocardiography, 6 minutes walk test and assessment of serum NT-proBNP level. Results. Preoperatively, 23.9% of patients had HFrEF, 24.8% - HFmrEF and 51.3% - HFpEF. Analyzing the evolution of the HF phenotype in the early postoperative period, we found that most patients remained in the same group. However, among patients with preoperative HFmrEF, in 22.2% of patients there was an increase in LV EF over 50% and in 22.2% of patients was determined a reduced LV EF, p<0.001. The most obvious positive dynamic of the HF phenotype was attested in patients with HFrEF, where 37% of them presented a mildly reduced LV EF postoperatively, p <0.001. 78.9% of individuals with HFpEF remained in the same group, but 21% showed a decrease in LV EF, p<0.001. Conclusions. At the early stage after cardiac surgery, the most positive evolution of HF phenotype was noticed in the group of patients with HFrEF. Of the 44.4% of patients with HFmrEF who switched to another HF phenotype, only a half reported an increase in LV EF over 50%. The vast majority of patients with HFpEF had the same HF phenotype postoperatively.Introducere. Insuficiența cardiacă (IC) este un factor de risc bine determinat pentru mortalitate și morbiditate în perioada precoce după intervenție chirurgicală cardiacă. Ne-am propus să analizăm evoluția fenotipului clinic al IC la etapa precoce după suportarea unei operații pe cord. Materiale și metode. Studiul a inclus 126 pacienți consecutivi cu IC cronică stabilită, care au urmat programul de reabilitare cardiacă după suportarea unei intervenții chirurgicale pe cord (62,23±8,59 ani, 67,5% bărbați). Subiecții au fost divizați în 3 grupuri în funcție de fenotipul clinic de IC: grupul 1 - IC cu fracția de ejecție (FE) a ventriculului stâng (VS) redusă (IC-FErVS), grupul 2 - IC cu FE VS ușor redusă (IC-FEurVS) și grupul 3 - IC cu FE VS prezervată (IC-FEpVS). Toți pacienții au fost investigați complex prin electrocardiografie, ecocardiografie transtoracică, test de mers plat 6 minute și evaluarea nivelului seric al NT-proBNP. Rezultate. Preoperator, 23,9% de pacienți au avut IC-FErVS, 24,8% - IC-FEurVS și 51,3% - IC-FEpVS. Analizând evoluția fenotipului de IC în perioada postoperatorie precoce, s-a observat că majoritatea pacienților au rămas în cadrul aceluiași grup. Totuși, dintre pacienții cu IC-FEurVS preoperator, la 22,2% bolnavi s-a atestat IC-FEpVS la etapa postoperatorie precoce, iar la 22,2% dintre bolnavi s-a determinat IC-FErVS, p<0,001. Cea mai evidentă dinamică pozitivă a fenotipului de IC s-a atestat la pacienții cu IC-FErVS, unde 37% dintre aceștia au prezentat postoperator o FE VS ușor redusă, p<0,001. 78,9% dintre indivizii cu IC-FEpVS au rămas în același grup, iar 21% au manifestat o diminuare a fracției de ejecție a VS, p<0,001. Concluzii. În grupul de pacienți cu IC-FErVS s-a remarcat o dinamică pozitivă mai importantă a fenotipului IC la etapa precoce după intervenția chirurgicală cardiacă. Dintre cei 44,4% de pacienții cu IC-FEurVS care au manifestat tranziția spre un alt fenotip de IC, doar jumătate a atestat majorarea FE VS peste 50%. La majoritatea covârșitoare a pacienților cu IC-FEpVS s-a stabilit același fenotip al IC postoperator.Вступление. Сердечная недостаточность (СН) является установленным фактором риска смертности и заболеваемости в раннем периоде после кардиохирургического вмешательства. Целью исследования было проанализировать эволюцию клинического фенотипа СН на ранней стадии после операции на сердце. Методы. В исследовании были включены 126 последовательных пациентов с признаками и симптомами хронической СН, госпитализированных для кардиологической реабилитации после операции на сердце (62,23±8,59 года, 67,5% - мужского пола). Пациенты были разделены на 3 группы в соответствии с клиническим фенотипом СН: 1 группа - СН со сниженной фракцией выброса (ФВ) левого желудочка (ЛЖ) (СНснФВ), 2 группа - СН с промежуточной ФВ ЛЖ (СНпФВ) и 3 группа - СН с сохраненной ФВ ЛЖ (СНсохрФВ). Все пациенты были обследованы с помощью электрокардиографии, трансторакальной эхокардиографии, теста 6-минутной ходьбы и определения уровня мозгового натрийуретического пептида. Результаты. До операции, 23,9% пациентов имели СНснФВ, 24,8% - СНпФВ и 51,3% - СНсохрФВ. Анализируя эволюцию фенотипа СН в раннем послеоперационном периоде, можно отметить, что большинство пациентов остались в той же группе. Однако среди пациентов с СНпФВ в предоперационном периоде, у 22,2% больных отмечалось увеличение ФВ ЛЖ выше 50% на раннем послеоперационном этапе, а у 22,2% пациентов определялась сниженная ФВ ЛЖ, p<0,001. Наиболее очевидная положительная динамика фенотипа СН отмечена у пациентов с СНснФВ, так как у 37% из них после операции ФВ ЛЖ стала выше 40%, p<0,001. 78,9% больных с СНсохрФВ осталось в той же группе, но 21% показали снижение ФВ ЛЖ, p<0,001. Выводы. В группе пациентов с СНснФВ отмечена наиболее очевидная положительная динамика фенотипа СН на раннем этапе после кардиохирургического вмешательства. Из 44,4% пациентов с СНпФВ у которых отмечен переход к другому фенотипу СН, только у половины больных ФВ ЛЖ превысила уровень 50%. Среди пациентов с СНсохрФВ перед операцией на сердце ФВ ЛЖ сохранялась выше 50% в подавляющем большинстве случаев и после кардиохирургического вмешательства

Developments in Capture- γ Libraries for Nonproliferation Applications

The neutron-capture reaction is fundamental for identifying and analyzing the γ-ray spectrum from an unknown assembly because it provides unambiguous information on the neutron-absorbing isotopes. Nondestructive-assay applications may exploit this phenomenon passively, for example, in the presence of spontaneous-fission neutrons, or actively where an external neutron source is used as a probe. There are known gaps in the Evaluated Nuclear Data File libraries corresponding to neutron-capture γ-ray data that otherwise limit transport-modeling applications. In this work, we describe how new thermal neutron-capture data are being used to improve information in the neutron-data libraries for isotopes relevant to nonproliferation applications. We address this problem by providing new experimentally-deduced partial and total neutron-capture reaction cross sections and then evaluate these data by comparison with statistical-model calculations

Calidad del suelo en zonas productoras de mango en el Departamento del Magdalena, Colombia

Sugar mango (Mangifera indica L.) is cultivated in the department of Magdalena, municipalities of Santa Marta and Cienaga mainly, where it expresses its best agronomic behavior and best fruit quality. Its high demand has generated the need to increase the cultivation areas; however, there are no defined criteria to identify potential areas for its establishment. The study consisted of constructing a soil quality index for sugar mango production, based on twelve physical and fifteen chemical indicators of the soil. In six sugar mango farms in the department of Magdalena, three plots per farm of 350 m2 were selected and the properties of the soils were characterized in each plot. The characteristics of the soil where the cultivar expresses its highest yield and fruit quality were the reference indicators. The soil quality indicator was formulated based on the variables that explained greater variability and were more redundant based on their correlations. Additionally, a weight was given to each variable depending on its importance for agronomic behavior of the cultivar. The soil indicators showed variation, especially the nutrients Zn, Cu, Fe, S, and P in the chemical properties and infiltration and structure index in the physical properties. The chemical and physical variables with the greatest weight were pH and sand content, respectively. The proposed soil quality index turned out to be a good method to classify soil quality for sugar mango production based on physical and chemical soil indicators.El mango de azúcar (Mangifera indica L.) es cultivado en el departamento del Magdalena, municipios de Santa Marta y Ciénaga principalmente, lugar donde expresa su mejor comportamiento agronómico y mejor calidad de la fruta. Su alta demanda ha generado la necesidad de aumentar las áreas del cultivo; sin embargo, no existen criterios definidos para identificar zonas potenciales para su establecimiento. El estudio consistió en construir un índice de calidad de suelo para la producción de mango en función de doce indicadores físicos y quince indicadores químicos de los suelos. En seis fincas de mango de azúcar del departamento del Magdalena se seleccionaron tres parcelas de 350 m2 por finca y en cada parcela se caracterizaron las propiedades físicas y químicas de los suelos. Las características de los suelos donde el cultivar expresa su mayor rendimiento y calidad de fruta fueron los indicadores de referencia para cada variable estudiada. El indicador de calidad de suelo se formuló en función de las variables que explicaban mayor variabilidad y fueron más redundantes en base a sus correlaciones. Adicionalmente, se dio un peso a cada variable dependiendo de su importancia para el comportamiento agronómico del cultivar. Los indicadores del suelo mostraron variación, especialmente los nutrientes Zn, Cu, Fe, S y P en las propiedades químicas y la infiltración y el índice de estructura en las propiedades físicas. Las variables químicas y físicas con mayor peso fueron el pH y el contenido de arena, respectivamente. El índice de calidad de suelo propuesto resultó ser un buen método para clasificar la calidad del suelo para la producción de mango de azúcar en función de indicadores físicos y químicos del suelo