Decomposition of Cattle Dung on Mixed Grass-Legume Pastures

Animal excreta contribute positively to nutrient cycling and can improve the quality of soil (Dubeux et al. 2009, Carvalho et al. 2010). Cattle excrement, when evenly distributed over a pasture, can help to maintain plant nutrition without the application of fertilizers. The introduction of legumes intercropped with grasses benefits the soil by means of nitrogen fixation. Also, when ruminant animals eat legumes, the excrement produced may have lower C:N, C:P, lignin:N and lignin:P ratios promoting better nutrient return to the soil compared to when cattle eat only grass. Given the importance of nutrient return and decomposition time of cattle excreta on pastures, the objective of this study was to evaluate the decomposition of excrement of heifers managed in mixed grass-shrubby legume pastures and grass-only pastures

Relationship between Field Measurements in Three \u3cem\u3eBrachiaria\u3c/em\u3e Species with Leaf Area Index and Light Interception by Indirect Methods

Brachiaria species play a strategic role in ruminant production systems in Brazil, covering an estimated pasture area of approximately 90 million hectares (Karia et al., 2006), however, these pastures are subject to different degrees of degradation due to inadequate management. In pasture management, field measurements such as canopy height, for example, are used by managers as a tool to establish parameters for the optimal point to cut the forage and for the post-grazing residue, in order to maximize production by harvesting at maximum of herbage mass accumulation, and to avoid problems associated to overgrazing, by setting ideal post-grazing height for forage regrowth. The use of the variables light interception (LI) and leaf area index (LAI) has been recommended as a tool for pasture management, based on the theory that, when the canopy reaches a light interception of 95%, the forage is near its maximum growth rate, which is called critical LAI (Brougham, 1956). The residual LAI refers to the leaf area of the post-grazed stubble. Residual LAI is used to establish the minimum leaf area necessary to ensure an efficient pasture regrowth (Lemos et al., 2014). Light interception and the LAI are difficult to measure at the farm level, due to the high cost of the equipment and technical feasibility of the process. The objective of this study was to evaluate the relationship between LI and LAI measured by two different equipment, with canopy height and soil cover in three species of Brachiaria

Therapeutic ultrasound as a potential male contraceptive: power, frequency and temperature required to deplete rat testes of meiotic cells and epididymides of sperm determined using a commercially available system

<p>Abstract</p> <p>Background</p> <p>Studies published in the 1970s by Mostafa S. Fahim and colleagues showed that a short treatment with ultrasound caused the depletion of germ cells and infertility. The goal of the current study was to determine if a commercially available therapeutic ultrasound generator and transducer could be used as the basis for a male contraceptive.</p> <p>Methods</p> <p>Sprague-Dawley rats were anesthetized and their testes were treated with 1 MHz or 3 MHz ultrasound while varying power, duration and temperature of treatment.</p> <p>Results</p> <p>We found that 3 MHz ultrasound delivered with 2.2 Watt per square cm power for fifteen minutes was necessary to deplete spermatocytes and spermatids from the testis and that this treatment significantly reduced epididymal sperm reserves. 3 MHz ultrasound treatment reduced total epididymal sperm count 10-fold lower than the wet-heat control and decreased motile sperm counts 1,000-fold lower than wet-heat alone. The current treatment regimen provided nominally more energy to the treatment chamber than Fahim's originally reported conditions of 1 MHz ultrasound delivered at 1 Watt per square cm for ten minutes. However, the true spatial average intensity, effective radiating area and power output of the transducers used by Fahim were not reported, making a direct comparison impossible. We found that germ cell depletion was most uniform and effective when we rotated the therapeutic transducer to mitigate non-uniformity of the beam field. The lowest sperm count was achieved when the coupling medium (3% saline) was held at 37 degrees C and two consecutive 15-minute treatments of 3 MHz ultrasound at 2.2 Watt per square cm were separated by 2 days.</p> <p>Conclusions</p> <p>The non-invasive nature of ultrasound and its efficacy in reducing sperm count make therapeutic ultrasound a promising candidate for a male contraceptive. However, further studies must be conducted to confirm its efficacy in providing a contraceptive effect, to test the result of repeated use, to verify that the contraceptive effect is reversible and to demonstrate that there are no detrimental, long-term effects from using ultrasound as a method of male contraception.</p

Canopy Height and Its Relationship with Leaf Area Index and Light Interception of Tropical Grasses

Photosynthetic tissues, mainly green leaves, are the major component of forage growth and development. The amount of these tissues in a forage plant is influenced directly by the cutting management, which is based on cutting frequency and stubble height. It is usual to recommend as a management practice to cut (or graze) the forage whenever it reaches a given stubble height. Brougham (1956) stated that, when the forage canopy is intercepting 95% of the photosynthetic active radiation, this is the critical leaf area index (LAI), which means the forage is near its maximum growth rate without shading itself. There is also the optimum LAI, where the forage reaches the maximum point of mass accumulation, indicating time to start grazing or cut. Generally the critical and optimum LAI have close values, but they are not necessarily the same (Brown and Blaser, 1968). This trial evaluated the relationship among canopy height, leaf area index, and light interception in ten different tropical grasses

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

Determinação experimental da constante de Planck pela observação da corrente de descarga de um capacitor

In this paper, we present an experimental method for the determination of Planck’s constant, based on the measurement of the discharge current of a capacitor on a LED, without the use of resistors. To develop this, we use a capacitor connected in parallel to a LED and observe the voltage on the capacitor during its discharge along with the current flowing through the ammeter connected in series to the LED. At the instant when the current becomes zero, the voltage applied on the LED corresponds to the cutoff voltage, by which we can determine the Planck’s constant. Moreover, we treat some important concepts about the quantum phenomena of the LED operation and present the results from this methodology, with some discussions. Neste artigo nós apresentamos um método experimental para a determinação da constante de Planck, baseado na medição da corrente de descarga de um capacitor sobre um LED, sem o uso de resistores. Para tanto, utilizamos um capacitor ligado em paralelo a um LED e observamos a tensão no capacitor durante sua descarga juntamente com a corrente que passa através do amperímetro, ligado em série ao LED. No instante em que a corrente torna-se zero, a tensão aplicada sobre o LED corresponde à tensão de corte, pela qual podemos determinar a constante de Planck. Além disso, nós discutimos alguns conceitos importantes a respeito dos aspectos quânticos do funcionamento do LED e apresentamos os resultados obtidos a partir desta metodologia, com algumas discussões

Determinação experimental da constante de Planck pela observação da corrente de descarga de um capacitor

Neste artigo nós apresentamos um método experimental para a determinação da constante de Planck, baseado na medição da corrente de descarga de um capacitor sobre um LED, sem o uso de resistores. Para tanto, utilizamos um capacitor ligado em paralelo a um LED e observamos a tensão no capacitor durante sua descarga juntamente com a corrente que passa através do amperímetro, ligado em série ao LED. No instante em que a corrente torna-se zero, a tensão aplicada sobre o LED corresponde à tensão de corte, pela qual podemos determinar a constante de Planck. Além disso, nós discutimos alguns conceitos importantes a respeito dos aspectos quânticos do funcionamento do LED e apresentamos os resultados obtidos a partir desta metodologia, com algumas discussões

Stimulus-response compatibility as a tool for studying motor behavior

Quand un stimulus aparait aléatoirement à gauche ou a droite du point de fixation, la réponse est plus rapide lorsque le stimulus et le levier de réponse sont du même coté (condition compatible) que lorsque ceux-ci sont oposés (condition incompatible). Dans la tâche de compatibilité spatiale, la différence de temps de réaction manuel (TRMs) entre les conditions compatible et incompatible est de l´ordre de 30-40 ms. Dans l´effet Simon, bien que le critère de selection da réponse soit la forme (ou la couleur) du stimulus, la position du stimulus influence également le TRM, produisant une facilitation dans la condition compatible et un retard dans la condition incompatible. L´effet Simon peut être inverté si le sujet réalise des testes incompatibles préalablement au test Simon. Ceci démontre que les assocations à court terme, produites par les appariements incompatibles, modulent les types de connexions stimulus-réponse basés sur la mémoire à long terme.Quando um estímulo ocorre aleatoriamente à esquerda ou à direita do ponto de fi xação, a resposta é mais rápida quando o estímulo e a tecla de resposta estão do mesmo lado (condição compatível) do que quando estão em lados opostos (condição incompatível). Na tarefa de compatibilidade espacial, observa-se uma diferença entre os Tempos de Reação Manual (TRMs) nas condições compatível e incompatível da ordem de 30-40 ms. No Efeito Simon, embora o critério para a seleção da resposta seja a forma (ou a cor) do estímulo, a posição do estímulo também infl uencia o TRM, facilitando-o na condição compatível e lentifi cando-o na incompatível. O Efeito Simon pode ser invertido se a pessoa realiza testes incompatíveis previamente ao teste Simon, mostrando que associações de curto prazo, geradas pelos pareamentos incompatíveis modulam padrões de conexões estímulo-resposta baseados na memória de longo prazo.When a visual stimulus is randomly displayed either to the left or to the right of the fixation point, manual response is faster when both the response key and the stimulus are located at the same side (compatible condition) than at opposite sides (incompatible condition). In a spatial compatibility task, a difference of 30-40 ms is found between the manual reaction times (MRT) of compatible and incompatible conditions. In the Simon effect, though the criterion to response selection is primarily stimulus shape (or color), the stimulus position also influences the MRT, either increasing it in the compatible condition or delaying it in the incompatible condition. The Simon effect can be inverted if the subject has recently performed incompatible tasks, showing that short-term memory processes elicited by the incompatible associations can modulate stimulus-response relationships based on long-term memory