1,178 research outputs found
Cold Nuclear Matter Effects and Heavy Quark Production in PHENIX
The PHENIX experiment uses semileptonic decay channels to measure open and
closed heavy flavor cross sections across the rapidity range .
High luminosity data are now available for p+p, d+Au, Cu+Cu and Au+Au
collisions at =200 GeV, and for Au+Au collisions at
= 62 GeV. We discuss recent d+Au results for open heavy flavor
and production, and discuss their implications for the cold nuclear
matter contributions to heavy flavor production in heavy ion collisions.Comment: 8 pages, 9 figures. Proceedings for talk at Hard Probes 201
Variational approach to coarse-graining of generalized gradient flows
In this paper we present a variational technique that handles coarse-graining and passing to a limit in a unified manner. The technique is based on a duality structure, which is present in many gradient flows and other variational evolutions, and which often arises from a large-deviations principle. It has three main features: (A) a natural interaction between the duality structure and the coarse-graining, (B) application to systems with non-dissipative effects, and (C) application to coarse-graining of approximate solutions which solve the equation only to some error. As examples, we use this technique to solve three limit problems, the overdamped limit of the Vlasov-Fokker-Planck equation and the small-noise limit of randomly perturbed Hamiltonian systems with one and with many degrees of freedom
Evaluation for substitution of stem bark with small branches of Myrica esculenta for medicinal use – A comparative phytochemical study
AbstractBackgroundOver exploitation of many traditional medicinal plants like Myrica esculenta has become a threat and in the near future, many medicinal plants may be unavailable for use of industry.ObjectivePresent study outlines the concept of plant part substitution. Stem bark and small branches of M. esculenta are compared on the basis of physicochemical analysis, phytochemical analysis, total phenolic contents, total flavonoid contents and high performance thin layer chromatography (HPTLC) to evaluate the possibilities of using small branches in place of stem bark.Material and methodsPhysicochemical parameters and preliminary phytochemical screening were carried out using standard methods. Total phenolic and total flavonoid contents were estimated spectrophotometrically using Folin-Ciocalteu and aluminum chloride method, respectively. CAMAG HPTLC system equipped with semi-automatic applicator was used for HPTLC profiling. n-Hexane, ethyl acetate and ethanol extracts of stem bark and small branches were developed in suitable mobile phase using standard procedures and visualized in UV 254 and 366Â nm and in white light after derivatization within anisaldehyde-sulphuric acid reagent.ResultsPhytochemical analysis and HPTLC profile of different extracts showed the presence of almost similar phytochemicals in both stem bark and small branches.ConclusionSimilarities in phytochemical analysis and HPTLC profile of various extracts suggests that small branches may be used in place of stem bark. The study provides the base for further study to use small branches as a substitute of stem bark of M. esculenta
On the scaling approach to electron-electron interactions in a chaotic quantum dot
A scaling theory is used to study the low energy physics of electron-electron
interactions in a double quantum dot. We show that the fact that electrons are
delocalized over two quantum dots does not affect the instability criterion for
the description of electron-electron interactions in terms of a ``universal
interaction Hamiltonian''.Comment: 4 pages, 3 figure
Novel codon-optimized mini-intronic plasmid for efficient, inexpensive, and xeno-free induction of pluripotency
The development of human induced pluripotent stem cell (iPSC) technology has revolutionized the regenerative medicine field. This technology provides a powerful tool for disease modeling and drug screening approaches. To circumvent the risk of random integration into the host genome caused by retroviruses, non-integrating reprogramming methods have been developed. However, these techniques are relatively inefficient or expensive. The mini-intronic plasmid (MIP) is an alternative, robust transgene expression vector for reprogramming. Here we developed a single plasmid reprogramming system which carries codon-optimized (Co) sequences of the canonical reprogramming factors (Oct4, Klf4, Sox2, and c-Myc) and short hairpin RNA against p53 ("4-in-1 CoMiP"). We have derived human and mouse iPSC lines from fibroblasts by performing a single transfection. Either independently or together with an additional vector encoding for LIN28, NANOG, and GFP, we were also able to reprogram blood-derived peripheral blood mononuclear cells (PBMCs) into iPSCs. Taken together, the CoMiP system offers a new highly efficient, integration-free, easy to use, and inexpensive methodology for reprogramming. Furthermore, the CoMIP construct is color-labeled, free of any antibiotic selection cassettes, and independent of the requirement for expression of the Epstein-Barr Virus nuclear antigen (EBNA), making it particularly beneficial for future applications in regenerative medicine
A rapid staining technique for the detection of the initiation of germination of bacterial spores
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75645/1/j.1472-765x.2002.01047.x.pd
Data-driven models for canopy temperature-based irrigation scheduling
Normalized crop canopy temperature, termed crop water stress index (CWSI), was proposed over 40 years ago as an irrigation management tool but has experienced limited adopted in production agriculture. Development of generalized crop-specific upper and lower reference temperature is critical for implementation of CWSI-based irrigation scheduling. The objective of this study was to develop and evaluate data driven models for predicting reference canopy temperatures needed to compute CWSI for sugarbeet and wine grape. Reference canopy temperatures for sugarbeet and wine grape were predicted using machine learning and regression models developed using measured canopy temperatures of sugarbeet, grown in Idaho and Wyoming, and wine grape, grown in Idaho and Oregon, over 5 years under full and severe deficit irrigation. Lower reference temperatures were estimated using neural network models with Nash-Sutcliffe model efficiencies exceeding 0.88 and root mean square error less than 1.1 degree Celsius. The relationship between well-watered canopy temperature minus ambient temperature and vapor pressure deficit was represented by a linear model that maximized the regression coefficient rather than minimized the sum of squared error. The linear models were used to estimate upper reference temperatures nearly double values reported in previous studies. Daily CWSI calculated as the average of 15-min values determined between 13:00 and 16:00 MDT for sugarbeet and 13:00 and 15:00 local time for wine grape was well correlated with irrigation events and amounts. A quadratic relationship between daily CWSI and midday leaf water potential of Malbec and Syrah wine grape was significant (p<0.001) with an R2 of 0.67. The data driven models developed in this study to estimate reference temperatures permit automated calculation of CWSI for effective assessment of crop water stress, however, wet canopy conditions or solar radiation < 200 W m-2 can result in irrational values of CWSI. Automated calculation of CWSI using the methodology of this study would need to check for wet canopy or low solar radiation conditions and omit calculation of CWSI if determined to be probable
Resonance approximation and charge loading/unloading in adiabatic quantum pumping
Quantum pumping through mesoscopic quantum dots is known to be enhanced by
resonant transmission. The pumped charge is close to an integer number of
electrons when the pumping contour surrounds a resonance, but the transmission
remains small on the contour. For non-interacting electrons, we give a
quantitative account of the detailed exchange of electrons between the dot and
the leads (to the electron reservoirs) during a pumping cycle. Near isolated
distinct resonances, we use approximate Breit-Wigner expressions for the dot's
Green function to discuss the loading/unloading picture of the pumping: the
fractional charge exchanged between the dot and each lead through a single
resonance point is related to the relative couplings of the dot and the leads
at this resonance. If each resonance point along the pumping contour is
dominated by the coupling to a single lead (which also implies a very small
transmission), then the crossing of each such resonance results in a single
electron exchange between the dot and that lead, ending up with a net quantized
charge. When the resonance approximation is valid, the fractional charges can
also be extracted from the peaks of the transmissions between the various
leads.Comment: 10 pages, 4 figure
The effect of dietary intervention on the metabolic and behavioural impairments generated by short term high fat feeding in the rat
AbstractPrevious studies have shown that rats fed a high calorie diet rich in saturated fat for 12weeks exhibit peripheral insulin resistance and impairments of behavioural flexibility when switched from an operant delayed matching to place (DMTP) schedule to a delayed non-matching to place (DNMTP) schedule. However, the metabolic changes evoked by feeding a high fat (HF) diet can be observed within two weeks of commencing the diet. The current study has confirmed that 4weeks exposure to an HF diet resulted in increased body weight, peripheral insulin resistance and plasma leptin. Studies performed during weeks 3 and 4 on the HF diet revealed suppressed lever pressing rates and impaired behavioural flexibility in the operant DMTP/DNMTP task. When animals fed the HF diet were then returned to a standard chow (SC) diet for 5weeks their weight and blood biochemistry no longer differed from those measured in animals that had never been exposed to the HF diet. The animals restored to the SC diet exhibited a clear ability to acquire the DNMTP schedule of reinforcement although these animals continued to lever press at a lower rate when compared with animals that received the SC diet throughout. The data suggest that exposure to an HF diet diminishes the motivation to respond for a reward and, thus, the capacity to adapt behavioural performance. This deficit was ameliorated, but not totally reversed, by the dietary intervention. If also true for humans, the results suggest that deficits in behavioural flexibility develop after only a short period on a high calorie diet but may be largely reversible through simple dietary intervention, at least in the early stages of deficit development. However, the putative effects of short-term exposure to an HF diet on behavioural motivation may persist for some time after switching to a healthier low fat diet and remain a problem for those seeking to adopt a healthier diet
Magnetism in Dense Quark Matter
We review the mechanisms via which an external magnetic field can affect the
ground state of cold and dense quark matter. In the absence of a magnetic
field, at asymptotically high densities, cold quark matter is in the
Color-Flavor-Locked (CFL) phase of color superconductivity characterized by
three scales: the superconducting gap, the gluon Meissner mass, and the
baryonic chemical potential. When an applied magnetic field becomes comparable
with each of these scales, new phases and/or condensates may emerge. They
include the magnetic CFL (MCFL) phase that becomes relevant for fields of the
order of the gap scale; the paramagnetic CFL, important when the field is of
the order of the Meissner mass, and a spin-one condensate associated to the
magnetic moment of the Cooper pairs, significant at fields of the order of the
chemical potential. We discuss the equation of state (EoS) of MCFL matter for a
large range of field values and consider possible applications of the magnetic
effects on dense quark matter to the astrophysics of compact stars.Comment: To appear in Lect. Notes Phys. "Strongly interacting matter in
magnetic fields" (Springer), edited by D. Kharzeev, K. Landsteiner, A.
Schmitt, H.-U. Ye
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