Investigation of remote sensing techniques of measuring soil moisture

Major activities described include development and evaluation of theoretical models that describe both active and passive microwave sensing of soil moisture, the evaluation of these models for their applicability, the execution of a controlled field experiment during which passive microwave measurements were acquired to validate these models, and evaluation of previously acquired aircraft microwave measurements. The development of a root zone soil water and soil temperature profile model and the calibration and evaluation of gamma ray attenuation probes for measuring soil moisture profiles are considered. The analysis of spatial variability of soil information as related to remote sensing is discussed as well as the implementation of an instrumented field site for acquisition of soil moisture and meteorologic information for use in validating the soil water profile and soil temperature profile models

Identificação e composição química de espécies de invasoras consumidas por bovinos em pastagens cultivadas em Paragominas, Pará.

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Effect of the tropical tannin-rich shrub legumes Calliandra calothyrsus and Flemingia macrophylla on methane emission and nitrogen and energy balance in growing lambs

The objective of this study was to test whether the use of tannin-rich shrub legume forage is advantageous for methane mitigation and metabolic protein supply at unchanged energy supply when supplemented in combination with tannin-free legumes to sheep. In a 6 × 6 Latin-square design, foliage of two tannin-rich shrub legume species (Calliandra calothyrsus and Flemingia macrophylla) were used to replace either 1/3 or 2/3, respectively, of a herbaceous high-quality legume (Vigna unguiculata) in a diet composed of the tropical grass Brachiaria brizantha and Vigna in a ratio of 0.55 : 0.45. A Brachiaria-only diet served as the negative control. Each experimental period lasted for 28 days, with week 3 serving for balance measurement and data collection inclusive of a 2-day stay of the sheep in open-circuit respiration chambers for measurement of gaseous exchange. While Vigna supplementation improved protein and energy utilisation, the response to the partial replacement with tannin-rich legumes was less clear. The apparent total tract digestibilities of organic matter, NDF and ADF were reduced when the tannin-rich plants partially replaced Vigna, and the dose-response relationships were mainly linear. The tannin-rich plants caused the expected redistribution of more faecal N in relation to urinary N. While Flemingia addition still led to a net body N retention, even when fed at the higher proportion, adding higher amounts of Calliandra resulted in body protein mobilisation in the growing lambs. With respect to energy, supplementation of Vigna alone improved utilisation, while this effect was absent when a tannin-rich plant was added. The inclusion of the tannin-rich plants reduced methane emission per day and per unit of feed and energy intake by up to 24% relative to the Vigna-only-supplemented diet, but this seems to have been mostly the result of a reduced organic matter and fibre digestion. In conclusion, Calliandra seems less apt as protein supplement for ruminants while Flemingia could partially replace a high-quality legume in tropical livestock systems. However, methane mitigation would be small due to associated reductions in N and energy retentio

SARS-CoV-2 and Guillain-Barré syndrome: AIDP variant with a favourable outcome.

The spectrum of COVID-19, caused by severe acute respiratory syndrome coronavirus 2 infection (SARS-CoV-2), includes different neurologic manifestations of the central and peripheral nervous system. From March through April 2020, in two university hospitals located in western Switzerland, we examined three patients with Guillain-Barré syndrome (GBS) following SARS-CoV-2. These cases were characterized by a primary demyelinating electrophysiological pattern (Acute inflammatory demyelinating polyneuropathy or AIDP) and a less severe disease course compared to recently published case series. Clinical improvement was observed in all patients at week five. One patient was discharged from hospital after full recovery with persistence of minor neurological signs (areflexia). Two of the three patients remained hospitalized: one was able to walk and the other could stand up with assistance. We report three cases of typical GBS (AIDP) occurring after SARS-CoV-2 infection and presenting with a favourable clinical course. Given the interval between COVID-19-related symptoms and neurological manifestations (mean of 15 days) we postulate a secondary immune-mediated mechanism rather than direct viral damage

Retos de la ganadería para reducir la emisión de gases de efecto invernadero y adaptarse a los impactos de corto y largo plazo del cambio climático

El presente artículo tiene como objetivos describir las causas y las consecuencias del cambio climático a nivel global y en el contexto del país y presentar de forma resumida el resultado de la actividad pecuaria en la emisión de gases de efecto invernadero. La última sección del artículo está dedicada a proponer y discutir algunas estrategias de investigación para reducir la emisión de estos gases en los diferentes sistemas de producción pecuaria y mejorar su capacidad de adaptación a eventos extremos como exceso de lluvias, sequía, heladas e incidencia de plagas y enfermedades

Prognostic biomarkers in primary progressive multiple sclerosis: validating and scrutinizing multimodal evoked potentials

OBJECTIVE: To validate the prognostic value of multimodal evoked potentials (mmEP) in primary progressive multiple sclerosis (PPMS) and to determine the most predictive EP-modalities. METHODS: Thirty-nine patients with PPMS (expanded disability status scale (EDSS): 2.0-6.5; mean clinical follow-up: 2.8 years) had visual (VEP), upper and lower limb somatosensory (SEP) and motor EP (MEP) at baseline. Quantitative EP-scores for single (qVEP, qSEP, qMEP) and combined modalities were correlated to EDSS and compared to previously published data of 21 PPMS patients. Predictors of EDSS-change were analyzed in pooled data by linear regression. RESULTS: Samples were comparable. Except qVEP, all EP-scores were correlated to EDSS at baseline (Rho: 0.45-0.69; p < 0.01) and follow-up (Rho: 0.59-0.80; p < 0.001). Combined EP-modalities significantly predicted EDSS-change (R(2)adj: 0.24), while EDSS and age did not. Tibial qSEP (R(2)adj: 0.22) and qMEP (R(2)adj: 0.26) were the best single modality predictors, outperformed by their combination (R(2)adj: 0.32). CONCLUSIONS: Quantitative EP-scores predict up to 32% of EDSS-change over three years. Modalities representing motor and long tract function carry the main prognostic information. SIGNIFICANCE: Replication of previous results corroborates the use of mmEP as a prognostic biomarker candidate in PPMS

Measurement and modelling of photosynthetic response of pearl millet to soil phosphorus addition

There have been no studies of the effects of soil P deficiency on pearl millet (Pennisetum glaucum (L.) R. Br.) photosynthesis, despite the fact that P deficiency is the majorxonstraint to pearl millet production in most regions of West Africa. Because current photosynthesis-based crop simulation models do not explicitly take into account P deficiency effects on leaf photosynthesis, they cannot predict millet growth without extensive calibration. We studied the effects of soil addition on leaf P content, photosynthetic rate (A), and whole-plant dry matter production (DM) of non-water-stressed, 28 d pearl millet plants grown in pots containing 6.00 kg of a P-deficient soil. As soil P addition increased from 0 to 155.2 mg P kg- 1 soil, leaf P content increased from 0.65 to 7.0 g kg-1 . Both A and DM had maximal values near 51.7 mg P kg- 1 soil, which corresponded to a leaf P content of 3.2 g kg- 1. Within this range of soil P addition, the slope of A plotted against stomatal conductance (gs) tripled, and mean leaf internal CO2 concentration ([CC^];) decreased from 260 to 92 pL L~'., thus indicating that P deficiency limited A through metabolic dysfunction rather than stomatal regulation. Light response curves of A, which changed markedly with P leaf content, were modelled as a single substrate, Michaelis-Menten reaction, using quantum flux as the substrate for each level of soil P addition. An Eadie-Hofstee plot of light response data revealed that both Km, which is mathematically equivalent to quantum efficiency, and Vmax, which is the light-saturated rate of photosynthesis, increased sharply from leaf P contents of 0.6 to 3 g kg-1 , with peak values between 4 and 5 g P kg-1 . Polynomial equations relating Km and Vmax, to leaf P content offered a simple and attractive way of modelling photosynthetic light response for plants of different P status, but this approach is somewhat complicated by the decrease of leaf P content with ontogeny

Soil Phosphorus Availability and Pearl Millet Water-Use Efficiency

The effects of P and water stress on transpirational water-use efficiency (WUET) of pearl millet (Pennisetum glaucum) cv. ICTP 8203 were studied in outdoor pot and growth chamber experiments. Plants were grown outdoors under semiarid conditions in covered pots containing 85 kg of acid, P-deficient Betis sand (sandy, siliceous, thermic Psammentic Paleustalf). Pots were given 0-7.77 g P/m² (equivalent to 0-70 kg P/ha), water stressed or not stressed, and plants harvested at 14-d intervals. Significant main and interactive effects on WUET due to P level, water treatment, and harvesting date occurred. The slope of the curve relating DM to cumulative transpiration increased with P level and water stress when data from all harvests were pooled. In the growth chamber, WUET of non-water-stressed plants ranged with increasing P level from 3.22 to 9.12 g/kg at 29 d after sowing (DAS) in pots containing 6 kg soil, and from 0.84 to 9.24 g/kg at 49 DAS in pots containing 18 kg soil. The ratio of leaf net photosynthetic rate to transpiration (WUEgas) at 500 µmol/m² per s photosynthetic photon flux density (PPFD) ranged from 1.88 µg/mg for plants receiving no P to 10.25 µg/mg for those receiving 0.31 g P/6 kg soil. Between PPFD levels of 500 and 2000 µmol/m² per s plants receiving no P increased WUEgas to only 3.60 µg/mg, whereas those receiving higher levels of P increased WUEgas to as much as 18.2 µg/mg. It was concluded that water supply in semiarid environments cannot be effectively managed for improved crop production without addressing soil fertility constraints

Development and application of process-based simulation models for cotton production: a review of past, present, and future directions

The development and application of cropping system simulation models for cotton production has a long and rich history, beginning in the southeastern United States in the 1960's and now expanded to major cotton production regions globally. This paper briefly reviews the history of cotton simulation models, examines applications of the models since the turn of the century, and identifies opportunities for improving models and their use in cotton research and decision support. Cotton models reviewed include those specific to cotton (GOSSYM, Cotton2K, COTCO2, OZCOT, and CROPGRO-Cotton) and generic crop models that have been applied to cotton production (EPIC, WOFOST, SUCROS, GRAMI, CropSyst, and AquaCrop). Model application areas included crop water use and irrigation water management, nitrogen dynamics and fertilizer management, genetics and crop improvement, climatology, global climate change, precision agriculture, model integration with sensor data, economics, and classroom instruction. Generally, the literature demonstrated increased emphasis on cotton model development in the previous century and on cotton model application in the current century. Although efforts to develop cotton models have a 40-year history, no comparisons among cotton models were reported. Such efforts would be advisable as an initial step to evaluate current cotton simulation strategies. Increasingly, cotton simulation models are being applied by non-traditional crop modelers, who are not trained agronomists but wish to use the models for broad economic or life cycle analyses. While this trend demonstrates the growing interest in the models and their potential utility for a variety of applications, it necessitates the development of models with appropriate complexity and ease-of-use for a given application, and improved documentation and teaching materials are needed to educate potential model users. Spatial scaling issues are also increasingly prominent, as models originally developed for use at the field scale are being implemented for regional simulations over large geographic areas. Research steadily progresses toward the advanced goal of model integration with variable-rate control systems, which use real-time crop status and environmental information to spatially and temporally optimize applications of crop inputs, while also considering potential environmental impacts, resource limitations, and climate forecasts. Overall, the review demonstrates a languished effort in cotton simulation model development, but the application of existing models in a variety of research areas remains strong and continues to grow

Algarroba Effects on Behavior and Dairy Production of Grazing Cows II. Rainy Season.

The influence of arborization with algarroba (Prosopis juliflora SW) on behavior and dairy production of grazing cows was evaluated. The trial was made in the rainy season, and six enclosures per arborization treatment were used (low arborization, with 1-7 trees/ha; mid-arborization, with 12-16 trees/ha; and high arborization, with 20-27 trees/ha). Activities were observed every ten minutes during the mornings and afternoons. The number of animals, and each animal´s activity time was recorded. The dairy production data were collected and compared through a randomized design with six repetitions (ANOVA). Significant differences were observed (P &lt; 0.05) to more arborization in grazing (155-173 min), and the monthly values observed were similar. In fields with low arborization, the cows ate less grass, whereas fields with mid and high arborization, the cows grazed longer, and produced more milk (11.2 and 12.59 kg/c/day)