Direct Measure of Giant Magnetocaloric Entropy Contributions in Ni-Mn-In

Off-stoichiometric alloys based on Ni 2 MnIn have drawn attention due to the coupled first order magnetic and structural transformations, and the large magnetocaloric entropy associated with the transformations. Here we describe calorimetric and magnetic studies of four compositions. The results provide a direct measure of entropy changes contributions including at the first-order phase transitions, and thereby a determination of the maximum field-induced entropy change corresponding to the giant magnetocaloric effect. We find a large excess entropy change, attributed to magneto-elastic coupling, but only in compositions with no ferromagnetic order in the high-temperature austenite phase. Furthermore, a molecular field model corresponding to antiferromagnetism of the low-temperature phases is in good agreement, and nearly independent of composition, despite significant differences in overall magnetic response of these materials

Energy Resource Transportation Governance: Case Studies of The Alberta Oil Sands and The Argentinian Vaca Muerta Shale Oil Fields

In recent years, there has been increasing focus on the economic and other benefits of the development of “unconventional” sources of oil—resources that cannot be produced using traditional production techniques—partly due to the increased scarcity of conventional oil reserves. This paper compares and contrasts unconventional oil resources in Canada and Argentina. Canada has deposits of bitumen known as oil sands/tar sands. Bitumen is “a thick, sticky form of crude oil that is so heavy and viscous that it will not flow unless it is heated or diluted with lighter hydrocarbons” (Government of Alberta 2009), and when mixed with sand and clay, is known as the oil sands. In Argentina there are shale oil formations, which is crude oil found in low-permeability rock formations. The unconventional hydrocarbons in Canada (the oil sands) and Argentina (shale oil) are significant resources for both countries, especially when compared with their conventional reserves. Though the institutional structure is different in both countries—Canada’s oil and gas and transportation companies are privately-owned, whereas in Argentina, they are partially government owned—the rhetoric of the discussions seems to be similar in both countries: many are in favor of development due to the significance of the economic benefits. However, in both countries, the development of transport infrastructure has been hindered by different factors, on environmental grounds, notably with regard to concerns regarding greenhouse gas emissions (in Canada) and lacking sufficient planning capabilities and institutional framework for long-term investments such as railroads (in Argentina)

Calorimetric and magnetic study for Ni50_{50}Mn36_{36}In14_{14} and relative cooling power in paramagnetic inverse magnetocaloric systems

The non-stoichiometric Heusler alloy Ni$_{50}$Mn$_{36}$In$_{14}$ undergoes a martensitic phase transformation in the vicinity of 345 K, with the high temperature austenite phase exhibiting paramagnetic rather than ferromagnetic behavior, as shown in similar alloys with lower-temperature transformations. Suitably prepared samples are shown to exhibit a sharp transformation, a relatively small thermal hysteresis, and a large field-induced entropy change. We analyzed the magnetocaloric behavior both through magnetization and direct field-dependent calorimetry measurements. For measurements passing through the first-order transformation, an improved method for heat-pulse relaxation calorimetry was designed. The results provide a firm basis for the analytic evaluation of field-induced entropy changes in related materials. An analysis of the relative cooling power (RCP), based on the integrated field-induced entropy change and magnetizing behavior of the Mn spin system with ferromagnetic correlations, shows that a significant RCP may be obtained in these materials by tuning the magnetic and structural transformation temperatures through minor compositional changes or local order changes

A comparative study of WASP-67b and HAT-P-38b from WFC3 data

Atmospheric temperature and planetary gravity are thought to be the main parameters affecting cloud formation in giant exoplanet atmospheres. Recent attempts to understand cloud formation have explored wide regions of the equilibrium temperature-gravity parameter space. In this study, we instead compare the case of two giant planets with nearly identical equilibrium temperature ($T_\mathrm{eq}$ $\sim 1050 \, \mathrm{K}$) and gravity ($g \sim 10 \, \mathrm{m \, s}^{-1})$. During $HST$ Cycle 23, we collected WFC3/G141 observations of the two planets, WASP-67 b and HAT-P-38 b. HAT-P-38 b, with mass 0.42 M$_\mathrm{J}$ and radius 1.4 $R_\mathrm{J}$, exhibits a relatively clear atmosphere with a clear detection of water. We refine the orbital period of this planet with new observations, obtaining $P = 4.6403294 \pm 0.0000055 \, \mathrm{d}$. WASP-67 b, with mass 0.27 M$_\mathrm{J}$ and radius 0.83 $R_\mathrm{J}$, shows a more muted water absorption feature than that of HAT-P-38 b, indicating either a higher cloud deck in the atmosphere or a more metal-rich composition. The difference in the spectra supports the hypothesis that giant exoplanet atmospheres carry traces of their formation history. Future observations in the visible and mid-infrared are needed to probe the aerosol properties and constrain the evolutionary scenario of these planets.Comment: 16 pages, 17 figures, 8 tables, accepted for publication in The Astronomical Journa

Qdensity - a Mathematica Quantum Computer Simulation

This Mathematica 5.2 package~\footnote{QDENSITY is available at http://www.pitt.edu/~tabakin/QDENSITY} is a simulation of a Quantum Computer. The program provides a modular, instructive approach for generating the basic elements that make up a quantum circuit. The main emphasis is on using the density matrix, although an approach using state vectors is also implemented in the package. The package commands are defined in {\it Qdensity.m} which contains the tools needed in quantum circuits, e.g. multiqubit kets, projectors, gates, etc. Selected examples of the basic commands are presented here and a tutorial notebook, {\it Tutorial.nb} is provided with the package (available on our website) that serves as a full guide to the package. Finally, application is made to a variety of relevant cases, including Teleportation, Quantum Fourier transform, Grover's search and Shor's algorithm, in separate notebooks: {\it QFT.nb}, {\it Teleportation.nb}, {\it Grover.nb} and {\it Shor.nb} where each algorithm is explained in detail. Finally, two examples of the construction and manipulation of cluster states, which are part of ``one way computing" ideas, are included as an additional tool in the notebook {\it Cluster.nb}. A Mathematica palette containing most commands in QDENSITY is also included: {\it QDENSpalette.nb} .Comment: The Mathematica 5+ package is available at: http://www.pitt.edu/~tabakin/QDENSITY/QDENSITY.htm Minor corrections, accepted in Computer Physics Communication

Effects of Aneuploidy on Genome Structure, Expression, and Interphase Organization in Arabidopsis thaliana

Aneuploidy refers to losses and/or gains of individual chromosomes from the normal chromosome set. The resulting gene dosage imbalance has a noticeable affect on the phenotype, as illustrated by aneuploid syndromes, including Down syndrome in humans, and by human solid tumor cells, which are highly aneuploid. Although the phenotypic manifestations of aneuploidy are usually apparent, information about the underlying alterations in structure, expression, and interphase organization of unbalanced chromosome sets is still sparse. Plants generally tolerate aneuploidy better than animals, and, through colchicine treatment and breeding strategies, it is possible to obtain inbred sibling plants with different numbers of chromosomes. This possibility, combined with the genetic and genomics tools available for Arabidopsis thaliana, provides a powerful means to assess systematically the molecular and cytological consequences of aberrant numbers of specific chromosomes. Here, we report on the generation of Arabidopsis plants in which chromosome 5 is present in triplicate. We compare the global transcript profiles of normal diploids and chromosome 5 trisomics, and assess genome integrity using array comparative genome hybridization. We use live cell imaging to determine the interphase 3D arrangement of transgene-encoded fluorescent tags on chromosome 5 in trisomic and triploid plants. The results indicate that trisomy 5 disrupts gene expression throughout the genome and supports the production and/or retention of truncated copies of chromosome 5. Although trisomy 5 does not grossly distort the interphase arrangement of fluorescent-tagged sites on chromosome 5, it may somewhat enhance associations between transgene alleles. Our analysis reveals the complex genomic changes that can occur in aneuploids and underscores the importance of using multiple experimental approaches to investigate how chromosome numerical changes condition abnormal phenotypes and progressive genome instability

A recursive algorithm for joint time-frequency wideband spectrum sensing

Abstract—In wideband spectrum sensing, secondary or un-licensed users take signal measurements over a given wide spectrum band and attempt to determine subbands for which the spectrum is idle and thus available for use. Some recent approaches to finding such spectrum holes generally employ some form of edge detection or energy detection. We propose an algorithm for joint time-frequency wideband spectrum sensing based on applying a form of temporal spectrum sensing together with a recursive tree search. The algorithm is able to detect spec-trum holes accurately even in the presence of bursting primary signals and primary signals whose power spectral densities have smooth band edges. Numerical results are presented which show the performance gain of the proposed algorithm over earlier approaches to wideband spectrum sensing.1 Index Terms—Cognitive radio, spectrum sensing, dynamic spectrum access I

Early Colonoscopy in Hospitalized Patients With Acute Lower Gastrointestinal Bleeding: A Nationwide Analysis.

Background: Performing colonoscopy within 24 h of presentation to the hospital is the accepted standard of care for patients with an acute lower gastrointestinal bleed (LGIB). Previous studies have failed to demonstrate the benefit of early colonoscopy (EC) on mortality. In this study, we wanted to see if there was a change in inpatient deaths (primary outcome), length of stay (LOS), and hospitalization charges (TOTCHG) (secondary outcomes) with EC compared to previous studies. Methods: Adults diagnosed with LGIB were identified using the International Classification of Disease 10th Revision codes from the National Inpatient Sample database for 2016 to 2019. EC was defined as the procedure performed within 24 h of hospitalization. Delayed colonoscopy (DC) was defined as a procedure performed after 24 h of presentation. The patient population was divided into EC and DC groups, and the effects of several covariates on outcomes were measured using binary logistic and multivariate regression analysis. Inverse probability treatment weighting (IPTW) was performed to adjust for confounding covariates. Results: There were 1,549,065 cases diagnosed with LGIB, of which 285,165 cases (18.4%) received a colonoscopy. A total of 107,045 (6.9%) patients received early colonoscopies. EC was associated with decreased inpatient deaths (0.9% in EC, and 1.4% in DC, P \u3c 0.001). However, upon IPTW, this difference was not present. EC was associated with a decreased LOS (median 3 days vs. 5 days, P \u3c 0.001) and TOTCHG (median $32,037 vs.$44,092, P \u3c 0.001). Weekend admissions (WA) were associated with fewer EC (31.6% in WA, and 39.5% in non-WA, P \u3c 0.001). WA did not affect inpatient deaths. Conclusions: EC was not associated with decreased inpatient deaths. There was no difference in endoscopic interventions in both EC and DC groups. The difference in inpatient deaths observed between the two groups was not evident upon adjusting the results for confounders. EC was associated with a decreased LOS, and TOTCHG in patients with LGIB