347 research outputs found
Flow measurements near a Reynolds ridge
The Reynolds ridge is a well-known phenomenon first observed
in 1854 by Henry David Thoreau. It was then rediscovered
by Langton in 1872, but Reynolds was the first to recognize
that the surface tension difference was the physical mechanism
behind its formation and saw the equality between the case of
a spreading film and that of a stagnant film met by oncoming
flow. However, it wasn't until McCutchen in 1970 that the
prediction of a boundary layer forming beneath the film was
introduced as the cause of the surface deformation rise ahead
of the film due to the retardation of the flow. The first quantitative
theory of the ridge was formed by Harper and Dixon
(1974), who stated that the surface tension gradient balances
the viscous shear stress generated in the boundary layer. Experimental
studies of the ridge so far include Schlieren visualizations
by Sellin (1968) as well as by Scott (1982) who measured
the surface slope across the ridge and found good comparisons
between the theoretical results of Harper and Dixon. Finally, it
was Scott who recognized that even at very low levels of surface
contamination the Reynolds ridge is found to exist
SITE-SPECIFIC VERSUS WHOLE-FIELD FERTILITY AND LIME MANAGEMENT IN MICHIGAN SOYBEANS AND CORN
Prior research into variable-rate application (VRA) of fertilizer nutrients has found profitability to be lacking in single nutrient applications to U.S. cereal crops. This study examines the yield and cost effects of VRA phosphorus, potassium and lime application on Michigan corn and soybean farm fields in 1998-2001. After four years, we found no yield gain from site-specific management, but statistically significant added costs, resulting in no gain in profitability. Contrary to results elsewhere, there was no evidence of enhanced spatial yield stability due to site-specific fertility management. Likewise, there was no evidence of decreased variability of phosphorus, potassium or lime after VRA treatment. Site-specific response functions and yield goals might also enhance the likelihood of profitable VRA in the future.Crop Production/Industries,
Kopfschmerzen und passagere Aphasie bei einer 35-jährigen Patientin
Zusammenfassung: Wir schildern den Fall einer 35-jährigen Patientin, die unter einer fulminant verlaufenden Frühsommer-Meningoenzephalitis litt und verstarb. Die Besonderheit dieses Falls ist, dass die junge Frau nicht direkt aus einem Endemiegebiet stammte und die Krankheit nicht, wie eigentlich typisch, im Frühling auftrat. Weiterhin zeigen wir auf, dass auch außerhalb der klassischen Endemiegebiete mit einer Zunahme an durch Zecken übertragenen Krankheiten zu rechnen ist. So kommen Zecken, wahrscheinlich bedingt durch den Klimawandel, zunehmend auch in höheren Lagen vo
Controlling Physical Systems with Symmetries
Symmetry properties of the evolution equation and the state to be controlled
are shown to determine the basic features of the linear control of unstable
orbits. In particular, the selection of control parameters and their minimal
number are determined by the irreducible representations of the symmetry group
of the linearization about the orbit to be controlled. We use the general
results to demonstrate the effect of symmetry on the control of two sample
physical systems: a coupled map lattice and a particle in a symmetric
potential.Comment: 6 page
Принцип диалогичности извлечения экспертных знаний при оценке инноваций
В статье предлагается использовать принцип диалогичности при прогнозе эффективности инновационных продуктов на основе экспертных данных. Извлечение знаний экспертов в процессе диалога осуществляется с учетом их общественной роли и психофизиологических возможностей с пользованием компьютерных систем поддержки решений
Speciation of phosphorus in a fertilized, reduced-till soil system: in-field treatment incubation study
Citation: Khatiwada, Raju, Ganga M. Hettiarachchi, David B. Mengel, and Mingwei Fei. “Speciation of Phosphorus in a Fertilized, Reduced-Till Soil System: In-Field Treatment Incubation Study.” Soil Science Society of America Journal 76, no. 6 (2012): 2006–18. https://doi.org/10.2136/sssaj2011.0299.Phosphorus management in reduced-tillage systems is a great concern for farmers. Conclusive positive results of deep-banding P fertilizers compared with broadcast application and the chemistry of reduced-tillage systems remain unclear. Knowledge of the dominant solid P species present in soil following application of P fertilizers and the resulting potential P availability would help us understand and efficiently manage P in reduced-tillage systems. The objective of this research was to study the influence of placement (broadcast vs. deep-band P), fertilizer source (granular vs. liquid P), and time on the reaction products of P under field conditions. Changes in soil pH, resin-extractable P, total P, and speciation of P were determined at different distances from the point of fertilizer application at 5 wk and 6 mo after P application at a rate of 75 kg ha−1 to a soil system that was under long-term reduced tillage. Resin-extractable P was lower for broadcast treatments compared with deep-band treatments for both time periods. Resin-extractable P was greater in the liquid P-treated soils than in the granular P-treated soils. Speciation results showed that granular P fertilizers tended to form Fe–P-like forms, whereas liquid forms remained in adsorbed P-like forms in the soil 5 wk after application; moreover, speciation results showed granular P fertilizers precipitated less when deep-banded. During the 6-mo period following application, reaction products of broadcast granular, broadcast liquid, and deep-band granular fertilizers transformed to Ca-phosphate or mixtures of Ca-, Fe- and adsorbed-phosphate-like forms, whereas deep-band liquid P remained as mainly adsorbed P-like forms. Deep-banding of P would most likely provide a solution that is both agronomically and environmentally efficient for reduced-till farmers
The Swiss Primary Hypersomnolence and Narcolepsy Cohort study (SPHYNCS): Study protocol for a prospective, multicentre cohort observational study
Narcolepsy type 1 (NT1) is a disorder with well-established markers and a suspected autoimmune aetiology. Conversely, the narcoleptic borderland (NBL) disorders, including narcolepsy type 2, idiopathic hypersomnia, insufficient sleep syndrome and hypersomnia associated with a psychiatric disorder, lack well-defined markers and remain controversial in terms of aetiology, diagnosis and management. The Swiss Primary Hypersomnolence and Narcolepsy Cohort Study (SPHYNCS) is a comprehensive multicentre cohort study, which will investigate the clinical picture, pathophysiology and long-term course of NT1 and the NBL. The primary aim is to validate new and reappraise well-known markers for the characterization of the NBL, facilitating the diagnostic process. Seven Swiss sleep centres, belonging to the Swiss Narcolepsy Network (SNaNe), joined the study and will prospectively enrol over 500 patients with recent onset of excessive daytime sleepiness (EDS), hypersomnia or a suspected central disorder of hypersomnolence (CDH) during a 3-year recruitment phase. Healthy controls and patients with EDS due to severe sleep-disordered breathing, improving after therapy, will represent two control groups of over 50 patients each. Clinical and electrophysiological (polysomnography, multiple sleep latency test, maintenance of wakefulness test) information, and information on psychomotor vigilance and a sustained attention to response task, actigraphy and wearable devices (long-term monitoring), and responses to questionnaires will be collected at baseline and after 6, 12, 24 and 36 months. Potential disease markers will be searched for in blood, cerebrospinal fluid and stool. Analyses will include quantitative hypocretin measurements, proteomics/peptidomics, and immunological, genetic and microbiota studies. SPHYNCS will increase our understanding of CDH and the relationship between NT1 and the NBL. The identification of new disease markers is expected to lead to better and earlier diagnosis, better prognosis and personalized management of CDH
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Memory CD8+ T Cells Balance Pro- and Anti-inflammatory Activity by Reprogramming Cellular Acetate Handling at Sites of Infection.
Serum acetate increases upon systemic infection. Acutely, assimilation of acetate expands the capacity of memory CD8+ T cells to produce IFN-γ. Whether acetate modulates memory CD8+ T cell metabolism and function during pathogen re-encounter remains unexplored. Here we show that at sites of infection, high acetate concentrations are being reached, yet memory CD8+ T cells shut down the acetate assimilating enzymes ACSS1 and ACSS2. Acetate, being thus largely excluded from incorporation into cellular metabolic pathways, now had different effects, namely (1) directly activating glutaminase, thereby augmenting glutaminolysis, cellular respiration, and survival, and (2) suppressing TCR-triggered calcium flux, and consequently cell activation and effector cell function. In vivo, high acetate abundance at sites of infection improved pathogen clearance while reducing immunopathology. This indicates that, during different stages of the immune response, the same metabolite-acetate-induces distinct immunometabolic programs within the same cell type
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