PROCESSOR DEMAND AND PRICE-MARKUP FUNCTIONS FOR CATFISH: A DISAGGREGATED ANALYSIS WITH IMPLICATIONS FOR THE OFF-FLAVOR PROBLEM

Off-flavor in catfish restricts farm marketings 10 to 45% depending on the season. The economic impact on society of this imposed supply restriction depends, in part, on the elasticity of demand for catfish. Econometric estimates based on disaggregated processing plant data indicate an elastic demand at the processor level but an inelastic demand at the farm level. Short-run social welfare gains from the elimination of off-flavor are estimated to equal 12.0% of farm revenues ($10.0 million in 1983). The inelastic demand for catfish at the farm level, however, means that most of the societal gains will accrue to individuals beyond the farm gate. Thus, an economic justification exists for public sector funding of off-flavor research.Demand and Price Analysis,

Did cover crop or animal manure ameliorate corn residue removal effects on soil mechanical properties after 10 years?

Crop residue removal may negatively affect soil mechanical properties, which are key components of soil quality. To evaluate potential long-term effects, we assessed the 10-yr impact of corn (Zea mays L.) residue removal (59 % of non-grain biomass annually) on surface soil mechanical properties (0–20 cm). We also evaluated whether adding carbon (C) amendments, such as using a winter rye (Secale cereale L.) cover crop or surface-applying cattle manure (24 Mg ha− 1 biannually) can ameliorate the effects of crop residue removal. This long-term study was under irrigated no-till continuous corn on a silt loam soil in south-central Nebraska, USA. Measurements included soil penetration resistance, field bulk density, aggregate strength, Atterberg limits (liquid limit, plastic limit, and plasticity index), Proctor maximum bulk density, and the water content at which the Proctor maximum bulk density (critical water content) occurs. Reduction in soil organic carbon (SOC) concentration explained most of the changes in soil mechanical properties. Long-term corn residue removal increased penetration resistance (+40 %) for the 0–20 cm depth, and reduced aggregate strength (− 44 %), plasticity index (− 22 %), and critical water content (− 13 %) in the 0–5 cm depth. Residue removal also reduced field bulk density (− 5%), liquid limit (− 12 %), and plastic limit (− 10 %) in the 0–10 cm depth, but increased Proctor maximum bulk density (+8 %) in the 0–5 cm depth. Winter rye cover crop reduced field bulk density (− 5%, 0–15 cm depth) and increased penetration resistance (+52 %, 0–20 cm depth). Surface-applied manure amendments increased the near-surface soil liquid limit (+8 %) and plastic limit (+8 %) in the 0–5 cm depth. Given the high rate of residue removal used in this experiment, our findings support that excessive corn residue removal over the long-term (~10 years) negatively affects near-surface soil mechanical properties, but that use of winter rye cover crop or surface-applied manure can minimally to partially ameliorate these effect

Dinâmica populacional e transformações socioespaciais: uma análise a partir da região do Vale do Taquari/RS

Este trabalho objetiva analisar a dinâmica populacional e as transformações socioespaciais que ocorreram na região do Vale do Taquari/RS, a partir da mobilidade rural-urbana e intrarregional. Para tal, foram analisados os dados da população, do Valor Bruto Adicionado e feitas análises cartográficas da região. Dentre as principais características verificadas na região, tem-se: a passagem de uma região essencialmente rural para urbana, tanto em relação à distribuição da população quanto às atividades econômicas; um processo de envelhecimento mais acelerado do que o RS; uma diversificação produtiva, mas com o predomínio do setor de serviços na maioria dos municípios; a concentração da população urbana e da geração da riqueza em torno da cidade polo, Lajeado; e o vínculo da região com a região metropolitana de Porto Alegre

Longitudinal metabolomics of human plasma reveals prognostic markers of COVID-19 disease severity

There is an urgent need to identify which COVID-19 patients will develop life-threatening illness so that medical resources can be optimally allocated and rapid treatment can be administered early in the disease course, when clinical management is most effective. To aid in the prognostic classification of disease severity, we perform untargeted metabolomics on plasma from 339 patients, with samples collected at six longitudinal time points. Using the temporal metabolic profiles and machine learning, we build a predictive model of disease severity. We discover that a panel of metabolites measured at the time of study entry successfully determines disease severity. Through analysis of longitudinal samples, we confirm that most of these markers are directly related to disease progression and that their levels return to baseline upon disease recovery. Finally, we validate that these metabolites are also altered in a hamster model of COVID-19

Prime movers : mechanochemistry of mitotic kinesins

Mitotic spindles are self-organizing protein machines that harness teams of multiple force generators to drive chromosome segregation. Kinesins are key members of these force-generating teams. Different kinesins walk directionally along dynamic microtubules, anchor, crosslink, align and sort microtubules into polarized bundles, and influence microtubule dynamics by interacting with microtubule tips. The mechanochemical mechanisms of these kinesins are specialized to enable each type to make a specific contribution to spindle self-organization and chromosome segregation

Comparing Skill Acquisition Under Varying Onsets of Differential Reinforcement: A Preliminary Analysis

The purpose of the current study was to evaluate the effect of implementing differential reinforcement at different times relative to the onset of teaching new skills to learners with autism spectrum disorder. Specifically, we first determined the most efficient differential reinforcement arrangement for each participant. Using the most efficient arrangement, we evaluated if differential reinforcement from the immediate onset, early onset, or late onset is the most efficient for learners to acquire a new skill. Three children diagnosed with autism spectrum disorder who have a history of receiving intervention based on the principles of applied behavior analysis participated in this study. The immediate onset of differential reinforcement resulted in the most efficient instruction in 6 of 7 comparisons. The results are discussed in light of previous studies and suggestions for future research are provided

'BeSAFE', effect-evaluation of internet-based, tailored safety information combined with personal counselling on parents' child safety behaviours: study design of a randomized controlled trial

Background. Injuries in or around the home are the most important cause of death among children aged 0-4 years old. It is also a major source of morbidity and loss of quality of life. In order to reduce the number of injuries, the Consumer Safety Institute introduced the use of Safety Information Leaflets in the Netherlands to provide safety education to parents of children aged 0-4 years. Despite current safety education, necessary safety behaviours are still not taken by a large number of parents, causing unnecessary risk of injury among young children. In an earlier study an E-health module with internet-based, tailored safety information was developed and applied. It concerns an advice for parents on safety behaviours in their homes regarding their child. The aim of this study is to evaluate the effect of this safety information combined with personal counselling on parents' child safety behaviours. Methods/Design. Parents who are eligible for the regular well-child visit with their child at child age 5-8 months are invited to participate in this study. Participating parents are randomized into one of two groups: 1) internet-based, tailored safety information combined with personal counselling (intervention group), or 2) personal counselling using the Safety Information Leaflets of the Consumer Safety Institute in the Netherlands for children aged 12 to 24 months (control group). All parents receive safety information on safety topics regarding the prevention of falling, poisoning, drowning and burning. Parents of the intervention group will access t

Multianalyte Sensing Of Addictive Over-the-counter (otc) Drugs

A supramolecular sensor array composed of two fluorescent cucurbit[n]uril-type receptors (probe 1 and probe 2) displaying complementary selectivities was tested for its ability to detect and quantify drug-related amines. The fluorimetric titration of the individual probes showed highly variable and cross-reactive analyte-dependent changes in fluorescence. An excellent ability to recognize a variety of analytes was demonstrated in qualitative as well as quantitative assays. Importantly, a successful quantitative analysis of several analytes of interest was achieved in mixtures and in human urine. The throughput and sensitivity surpass those of the current state-of-the-art methods that usually require analyte solid-phase extraction (SPE). These results open up the opportunity for new applications of cucurbit[n]uril-type receptors in sensing and pave the way for the development of simple high-throughput assays for various drugs in the near future