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

The Use of Cafeteria Trials for the Selection of \u3ci\u3eDesmodium ovalifolium\u3c/i\u3e Genotypes

For the selection of tropical legumes which contain anti-nutritive components such as tannins, relative acceptability of genotypes to ruminants is of particular importance, since these plant components may influence selective grazing behaviour and subsequent animal productivity. Plant-animal interactions are not predictable from laboratory analyses. Involving grazing animals through the conduction of relative-acceptability (=cafeteria) trials at early stages of the germplasm selection process might therefore provide a convenient tool to adjust and confirm genotype selection based on laboratory quality analyses data. As part of a multilocational germplasm evaluation project, cafeteria-experiments were conducted at two contrasting environments in Colombia with a core collection of Desmodium ovalifolium, a tropical legume species containing tannins. The objective of these experiments was to assess the usefulness of such acceptability trials in the selection of D. ovalifolium genotypes. Relative acceptability indices for the 18 accessions confirm genotype selection based on a series of laboratory quality analyses during earlier stages of the project and indicate pronounced genotype-environment interactions. Moreover, animal activity profiles confirm the influence of plant-environment-animal interactions and thus the usefulness of cafeteriatrials for germplasm selection projects

Condensed Tannins in Tropical Legumes: Concentration, Astringency and Effects on the Nutrition of Ruminants

A feeding trial was carried out to determine the effect of extractable condensed tannins (ECT) concentration and tannin astringency in tropical legumes on nitrogen (N) digestion by sheep. Test legumes were Desmodium ovalifolium (Do) and Flemingia macrophylla (Fm) which had similar concentrations of Extractable CT (9% DM) but tannins with different degree of astringency (Do, 0.6 and Fm, 0.3 g protein bound/g of ECT). Chopped sun-dried forage of each legume was sprayed with either water (control) or polyethylene glycol (PEG, 3.5% DM) to reduce ECT and fed to 8 sheep with ruminal and duodenal canulas arranged in a replicated 4 x 4 Latin Square changeover design. Greater (P\u3c0.05) N flow to duodenum, and fecal N were observed with Fm than with Do. Estimates of escape N were similar (58 to 61%) for both legumes. Reduction of ECT with PEG in both legumes (9.0-9.4 to 4.7-5.4%) resulted in lower (P\u3c0.05) proportion of N reaching the duodenum. Results indicate that concentration of ECT had a greater effect on N digestion by sheep than tannin astringency

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

Analysis of Coaxial Soil Cell in Reflection and Transmission

Accurate measurement of moisture content is a prime requirement in hydrological, geophysical and biogeochemical research as well as for material characterization and process control. Within these areas, accurate measurements of the surface area and bound water content is becoming increasingly important for providing answers to many fundamental questions ranging from characterization of cotton fiber maturity, to accurate characterization of soil water content in soil water conservation research to bio-plant water utilization to chemical reactions and diffusions of ionic species across membranes in cells as well as in the dense suspensions that occur in surface films. In these bound water materials, the errors in the traditional time-domain-reflectometer, “TDR”, exceed the range of the full span of the material’s permittivity that is being measured. Thus, there is a critical need to re-examine the TDR system and identify where the errors are to direct future research. One promising technique to address the increasing demands for higher accuracy water content measurements is utilization of electrical permittivity characterization of materials. This technique has enjoyed a strong following in the soil-science and geological community through measurements of apparent permittivity via time-domain-reflectometery as well in many process control applications. Recent research however, is indicating a need to increase the accuracy beyond that available from traditional TDR. The most logical pathway then becomes a transition from TDR based measurements to network analyzer measurements of absolute permittivity that will remove the adverse effects that high surface area soils and conductivity impart onto the measurements of apparent permittivity in traditional TDR applications. This research examines the theoretical basis behind the coaxial probe, from which the modern TDR probe originated from, to provide a basis on which to perform absolute permittivity measurements. The research reveals currently utilized formulations in accepted techniques for permittivity measurements which violate the underlying assumptions inherent in the basic models due to the TDR acting as an antenna by radiating energy off the end of the probe, rather than returning it back to the source as is the current assumption. To remove the effects of radiation from the experimental results obtain herein, this research utilized custom designed coaxial probes of various diameters and probe lengths by which to test the coaxial cell measurement technique for accuracy in determination of absolute permittivity. In doing so, the research reveals that the basic models available in the literature all omitted a key correction factor that is hypothesized by this research as being most likely due to fringe capacitance. To test this theory, a Poisson model of a coaxial cell was formulated to calculate the effective extra length provided by the fringe capacitance which is then used to correct the experimental results such that experimental measurements utilizing differing coaxial cell diameters and probe lengths, upon correction with the Poisson model derived correction factor, all produce the same results thereby lending support for the use of an augmented measurement technique, described herein, for measurement of absolute permittivity, as opposed to the traditional TDR measurement of apparent permittivity

Milk production of grazing Holstein x Zebu cows supplemented with Calliandra calothyrsus and Vigna unguiculata hays in Colombia

The effect of supplementing a low-quality Paspalum notatum pasture with hays of a tanniniferous and non-tanniniferous legume and mixtures thereof, on milk production and composition was tested at the CIAT Experiment Station, Cauca, Colombia during a dry season. Eight Holstein x Zebu cows were distributed among four treatments in a balanced change-over design with two animals per sequence. The treatments (supplements) were: T1: Calliandra calothyrsus 100%, T2: Vigna unguiculata 100%, T3: V. unguiculata/C. calothyrsus 67/33% and T4: C. calothyrsus/V. unguiculata 67/33%. The 3 ha pasture area consisted of two 1.5 ha paddocks, one for adjustment and the other for data collection, that were each grazed for 7 d during the four 14-d cycles of the 56-d experiment. The hay supplements were offered at milking time. Hay dry matter intake of 3.8 and 3.5 kg/d in T2 and T3 exceeded (P &lt; 0.05) that of T4 (2.6 kg), which in turn exceed T1 (1.2 kg). Daily 4% fat-corrected-milk production followed the same pattern with corresponding means of 5.3, 4.7, 4.4, and 3.6 kg. Ureic nitrogen level in milk was higher (P &lt; 0.05) for T2 and T3 (6.3 and 4.5 mg/dL) than for T1 and T4 (3.7 and 3.1 mg/dL). Milk total solids, fat and non-fat solids contents did no differ among treatments. It was concluded that tanniniferous legume hay alone depressed milk production, but its inclusion at 67% and especially 33% of the supplement had little effect

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

Flipped classroom aplicado a prácticas de laboratorio de la asignatura “Ampliación de Ciencia de Materiales”

[ES] El cambio de metodología de enseñanza que se realizó en las prácticas de laboratorio de la asignatura “Ampliación de ciencia de materiales” fue con el propósito de sacar ventaja de las peculiaridades que presenta el grupo, es decir un número reducido de estudiantes y tiempo de dedicación tanto dentro de clase como fuera de ella, factores que permitieron un mejor control del proceso de enseñanza. El proceso de aprendizaje al que fue expuesto este grupo de estudiante retó la capacidad innata que tiene el ser humano al autoaprendizaje y a descubrir cómo superar sus puntos débiles, sacando el mayor provecho al tiempo disponible de estudio, es decir, asimilando la mayoría cantidad de información con una mínima inversión de tiempo. La evaluación realizada durante todo el proceso fue satisfactoria no solo para el estudiante reflejadas en las calificaciones obtenidas, sino también para el tutor que pudo observar cómo evolucionó el interés de los estudiantes al envolverse cada vez más en el contenido de las prácticas, siendo notable en las prácticas finales.[EN] The new teaching methodology carried out in the laboratory class of the subject “Ampliación de ciencia de materiales” was used to take advantage of the peculiarities of the student group, that is in fact, it is a reduced number of students and great dedication time both in-class and out-class, factors that allowed better overall control of the process. The learning process to which the group of students was exposed challenged the innate capacity of the human being to self learn and to discover how to overcome their weak points, making the most of the available study time, that is, assimilating most of the information in less time. The evaluation carried out throughout the process was satisfactory not only for the student showed in the grades obtained, but also for the teacher in charge who could observe how the interest of the students evolved as they became increasingly involved in the content of the practice, being remarkable in the final class.Lascano, D.; Sánchez-Nacher, L.; Fombuena, V.; Rojas-Lema, S.; Montañés, N. (2021). Flipped classroom aplicado a prácticas de laboratorio de la asignatura “Ampliación de Ciencia de Materiales”. En IN-RED 2020: VI Congreso de Innovación Educativa y Docencia en Red. Editorial Universitat Politècnica de València. 218-223. https://doi.org/10.4995/INRED2020.2020.11976OCS21822

Effect of Calliandra calothyrsus, Flemingia macrophylla, Cratylia argentea and Vigna unguiculata silage and hay on in vitro gas production

The volume of gas produced when silage and hay of tanniniferous legumes were fermented was evaluated. There were 28 treatments (14 each of silages and hays, half with and half without polyethylene glycol (PEG) to inactivate the tannins) three replicates per treatment. The seven types of forage were: tanniniferous, Calliandra calothyrsus (CC) 100% and Flemingia macrophylla (FM) 100%, non-tanniniferous Vigna unguiculata (VU) 100% and Cratylia argentea (CA) 100%; and the mixtures CC 67%/VU 33%, FM 67%/VU 33%, and CA 67%/VU 33%. The Gas Trasducer Technique (GTT) of Theodorou and William was used to determine the in vitro fermentation rate and magnitude. Gas production data obtained during 144 h of incubation were fitted to the Gompertz model. The silages showed a greater rate of gas production (GPR) than the hays (P &lt; 0.05), but the latter were higher in dry matter degradability (DMD) and crude protein degradability (CPD) and ammonia liberation (NH3). The addition of PEG had little overall effect on GPR (but was effective with CC) or DMD, however it increased CPD and NH3 (P &lt; 0.05). As to the effect of forage type, VU excelled in GPR followed by CA/VU and FM/VU; VU was also highest in DMD followed by CA/VU; while CA, CA/VU and VU were highest in CPD; CC and FM were decidedly inferior in GPR and in vitro degradability