Phase function effects on oceanic light fields

Numerical simulations show that underwater radiances, irradiances, and reflectances are sensitive to the shape of the scattering phase function at intermediate and large scattering angles, although the exact shape of the phase function in the backscatter directions (for a given backscatter fraction) is not critical if errors of the order of 10% are acceptable. We present an algorithm for generating depth- and wavelength-dependent Fournier-Forand phase functions having any desired backscatter fraction. Modeling of a comprehensive data set of measured inherent optical properties and radiometric variables shows that use of phase functions with the correct backscatter fraction and overall shape is crucial to achieve model-data closure.     

Malnutrition in food-surplus areas: experience from nutritional surveillance for decentralized planning in Haiti

In Haiti, a novel approach to nutritional surveillance was developed on the basis of a low-cost, simple-to-repeat set of household surveys in all nine administrative departments using sentinel community sites. This system allows each department to independently conduct follow-up surveys as needed. The results of the first round of surveys conducted in 1995 show lower malnutrition rates in typical food-deficient departments and high levels of malnutrition in several food-surplus areas. Further analyses underscore the importance of variables related to child-care practices and of care-enabling factors such as household food security, health environment, and caregivers' time and education. These findings challenge the traditional thinking among a majority of Haitian policy makers who look at the malnutrition problem solely from the perspective of local food production.     

Harris Hawks Optimizer with Graph Convolutional Network Based Weed Detection in Precision Agriculture

Precision agriculture includes the optimum and adequate use of resources depending on several variables that govern crop yield. Precision agriculture offers a novel solution utilizing a systematic technique for current agricultural problems like balancing production and environmental concerns. Weed control has become one of the significant problems in the agricultural sector. In traditional weed control, the entire field is treated uniformly by spraying the soil, a single herbicide dose, weed, and crops in the same way. For more precise farming, robots could accomplish targeted weed treatment if they could specifically find the location of the dispensable plant and identify the weed type. This may lessen by large margin utilization of agrochemicals on agricultural fields and favour sustainable agriculture. This study presents a Harris Hawks Optimizer with Graph Convolutional Network based Weed Detection (HHOGCN-WD) technique for Precision Agriculture. The HHOGCN-WD technique mainly focuses on identifying and classifying weeds for precision agriculture. For image pre-processing, the HHOGCN-WD model utilizes a bilateral normal filter (BNF) for noise removal. In addition, coupled convolutional neural network (CCNet) model is utilized to derive a set of feature vectors. To detect and classify weed, the GCN model is utilized with the HHO algorithm as a hyperparameter optimizer to improve the detection performance. The experimental results of the HHOGCN-WD technique are investigated under the benchmark dataset. The results indicate the promising performance of the presented HHOGCN-WD model over other recent approaches, with increased accuracy of 99.13%.     

Assessment of grape yield and composition using the reflectance based Water Index in Mediterranean rainfed vineyards

In rainfed vineyards water deficits play a major role in determining berry yield and composition. Therefore, reliable indicators of vine water status might be of great value for the optimization of grape yield and quality. In the present study the feasibility of using hyperspectral reflectance indices related to plant biophysical properties at predicting berry yield and quality attributes in rainfed vineyards is assessed. The study was conducted on Vitis vinifera cv. Chardonnay in commercial vineyards in the D.O. Penedès region (Catalonia, Spain) over two consecutive years (2007–2008). Field measurements of fractional intercepted Photosynthetic Active Radiation (fIPAR), canopy reflectance, predawn water potential (Ψ_p) and the canopy to air temperature difference at midday (ΔT_midday) were conducted at the stage of veraison. Yield, Total Soluble Solids (TSS), Titratable Acidity (TA) and the ratio TSS/TA (maturation index, IMAD) were determined at harvest. Contrasted water availability among vineyards prompted considerable variation in berry yield and quality attributes. Across years, higher yield was accompanied by higher TA (r = 0.59, p < 0.01) and lower IMAD (r = ? 0.63, p < 0.01) while no significant relationship was observed between yield and TSS. Yield was related to canopy vigor (fIPAR) in a variable extend: in 2007, yield was positively related to fIPAR (r = 0.71, p < 0.05) while yield was found to decrease along with increasing fIPAR in 2008 (r = ? 0.62, p < 0.05). Contrastingly, NDVI provided consistent estimates of yield across years (r = 0.57, p < 0.05). These results suggest that NDVI might be more appropriate to characterize the effects of varying water availability on yield than fIPAR. In addition, yield was found to be related to ΔT_midday (r = ? 0.63 and r = ? 0.66, in 2007 and 2008, respectively). Accordingly, the Water Index (WI), an indicator of vine water status, provided robust estimates of yield across years (r = 0.61, p < 0.01). The strength of the correlation between NDVI and WI vs. yield suggests that yield was influenced by changes in both leaf area (intercepted light) and photosynthesis (stomatal aperture) in a variable extent according to the timing and severity of water deficits in the years of study. Berry quality attributes did not show significant relationships against fIPAR but were related to ΔT_midday. Accordingly, NDVI did not show significant correlation with berry quality attributes, while WI was found to be consistently related to TA (r = 0.70, p < 0.01) and IMAD (r = ? 0.71, p < 0.01) across years. The results obtained suggest that the WI might provide reliable estimates of berry quality attributes in vineyards experiencing moderate to severe water deficits with potential application in precision viticulture activities such as selective harvesting according to grape quality attributes as well as for ripening assessment.     

Combined use of waste materials—recovery of chitin from shrimp shells by lactic acid fermentation supplemented with date juice waste or glucose

BACKGROUND: Chitin, a source of chitosan, was extracted from the teguments of white shrimp Parapenaeus longirostris, by means of Lactobacillus helveticus growing on date juice waste or glucose for comparison. A fermentor containing 10% (w/v) of shrimp shells was inoculated with a suspension of L. helveticus strain milano (10% v/v). RESULTS: For an initial pH of 8.5–9.0 and a temperature of 30 °C, maximum deproteinization and demineralization were 76 and 53%, achieved for 80 and 300 g L^?1 glucose, respectively. The level of demineralization increased to 60% for an increase in in temperature from 30 to 35 °C. The use of date juice, as an alternative to the use of a primary carbon source such as glucose, led at best to 44% demineralization, for 208 g L^?1 of total sugar at 35 °C, and 91% deproteinization, for 80 g L^?1 total sugar content at 30 °C. CONCLUSION: Demineralization was not improved by the use of date juice, most likely due to its calcium content, which, during acidification, prevents the diffusion of calcium from the shells to the surrounding medium. Contrarily, the proteolytic activity of LAB appeared to be improved by the mineral content of date juice, leading to almost complete deproteinization of shrimp shells. Copyright © 2008 Society of Chemical Industry     

The interfunctionality of talk and text

Understanding more about how socially distributed cognition operates within a group of writers has implications for the design of technologies to support collaborative writing. This paper presents a chronology of a writing episode in which the communicative practices of collaborating writers and the representations they use to mediate cognition are investigated. The talk generated by the participants discussing how to write an essay provides data for illuminating the group's interactions and is a focus for investigating how this talk becomes metamorphosed into writing. The analysis charts the evolution of a co-authored text through a cycle of activity which is both cognitive and social in orientation and demonstrates the interfunctionality of talk and text for the processes involved in collaborative writing. This suggests that computer systems which support only text-based communication could limit the ways in which talk acts as a mediator for cognition and thus constrain important aspects of collaborative writing.     

Sampling Conformation Space to Model Equilibrium Fluctuations in Proteins

This paper proposes the Protein Ensemble Method (PEM) to model equilibrium fluctuations in proteins where fragments of the protein polypeptide chain can move independently of one another. PEM models global equilibrium fluctuations of a polypeptide chain by combining local fluctuations of consecutive overlapping fragments of the chain. Local fluctuations are computed by a probabilistic exploration that exploits analogies between proteins and robots. All generated conformations are subjected to energy minimization and then are weighted according to a Boltzmann distribution. Using the theory of statistical mechanics the Boltzmann-weighted fluctuations corresponding to each fragment are combined to obtain fluctuations for the entire protein. The agreement obtained between PEM-modeled fluctuations, wet-lab experiment and guided simulation measurements, indicates that PEM is able to reproduce with high accuracy protein equilibrium fluctuations that occur over a broad range of timescales.     

Functionally graded tricalcium phosphate/fluoroapatite composites

This study was conducted to prepare fluorine-substituted apatite (FA)/beta-tricalcium phosphate (β-TCP) composites to combine the biostability of FA with the bioresorbability of β-TCP. The FA was prepared for the first time by mixing hydroxyapatite (HA) with aluminium fluoride (coded as AF). On the other hand, the β-TCP was prepared from a mixture of HA and CaHPO₄ (calcium hydrogen phosphate). The dissolution behaviour of the composites was tested using a 10-wt.% citric acid solution. Scanning electron microscopy (SEM) indicated that β-TCP dissolved in the citric acid much faster than FA, resulting in macropores among the FA matrix. In addition to bulk FA/β-TCP composites, novel functionally gradient FA/β-TCP composites were also prepared by varying the particle size and the volume content of the β-TCP granules. The functionally gradient FA/β-TCP composites could be used to design implants.