Gender Differences in Cooperative Learning with University Students

Differences in achievement were investigated for 80 female and 80 male university students who were randomly assigned to either cooperative or competitive teaching methods. After viewing a videotaped instruction on research design, participants completed a mini-assignment either individually in the competitive condition or with a same-sex partner in the cooperative condition. All participants individually completed a multiple-choice test to assess achievement. Although no differences were found on the multiple-choice test, on the mini-assignment women scored significantly higher in the cooperative than in the competitive condition, whereas men performed about equally in both conditions.Nous avons étudié les différences de performance chez 80 étudiants et 80 étudiantes universitaires à qui l’on avait assigné, par hasard, un projet conforme, soit à des méthodes de coopération, soit à des méthodes concurrentielles. Après avoir visionné une vidéo de directives portant sur la méthodologie de recherche, les participants ont complété un petit travail seul, dans un contexte concurrentiel, ou bien avec un partenaire de même sexe dans un contexte de coopération. De plus, tous les participants ont complété un examen à choix multiples individuellement, pour mesurer leur performance. Les résultats de cet examen ne révèlent aucune différence. Toutefois, la note e qu’ont obtenue les femmes pour le petit travail était bien plus élevée pour celui accompli dans un contexte de coopération que dans un contexte de concurrence. La performance des hommes était semblable dans les deux contextes

Ariel - Volume 6 Number 1

Editors John Lammie Curt Cummings Frank Chervenak J.D. Kanofsky Mark Dembert Entertainment Robert Breckenridge Joe Conti Gary Kaskey Photographer Larry Glazerman Overseas Editor Mike Sinason Circulation Jay Amsterdam Humorist Jim McCann Staff Ken Jaffe Bob Sklaroff Halley Faus

Vertical Split Rim: Causes and Prevention

DTFR53-11-D-00008, Task Order 334Vertical split rim (VSR) is a serious railway wheel failure mode that requires further research. Visual clues are not usually present until the crack propagates through the rim. To better understand the root causes of VSRs, the Federal Railroad Administration (FRA) and the Association of American Railroads (AAR) have jointly funded the investigation of this problem. To better understand VSR, Transportation Technology Center, Inc. (TTCI) attempted to create this defect in a laboratory. A deep slit was cut into the tread of the wheel. After 1.8 million cycles at loads of 36\u201350 kips, the crack still did not propagate and no VSR was created. This test followed previous attempts of higher vertical wheel loads, but without a cut, that did not create VSR. Wheel manufacturers and TTCI previously tried to create a VSR under controlled conditions using a rolling load machine. In both previous instances, a VSR was not created

Life on Jackson Creek, Smith County, Texas: Archeological Investigations of a 14th Century Caddo Domicile at the Leaning Rock Site (41SM325)

The 14th century Caddo Leaning Rock site was initially discovered in the Fall of 2004. It was located during reconnaissance to search out a location for the survey portion of the Texas Archeologica! Society\u27s Academy IO I held in Tyler in February 2005. This was not a formal survey with transect lines. nor one using regularly spaced shovel tests. but was rather more of a windshield \u27 type survey, consisting of driving across pasture lands looking at gopher mounds and checking fore, evidence of archeological deposits on likely looking landforms. !n this area. landform and soil type seem to be the major determining factors in locating Caddo sites. The sandy soils in the scattered gopher mounds appeared almost white. especially in droughty conditions that prevailed at the time. causing an area with darker mounds of soil to catch my attention. Pocket gophers (G. breviceps) can play havoc with buried archeological deposits but can also be useful in bringing buried soils along with archeological materials to the surface from their underground tunnel system. While this dark area could have been the result of past historic land clearing and burning activities. a closer inspection revealed burned bone. mussel she!L and Caddo sherds mixed in the dark brown soils in the scattered gopher mounds. The next step was to record the site with the State of Texas, obtaining the trinomial 41SM325. It is common practice to also gin: sites informal names and after recording several hundred sites, selecting a name becomes a challenge. One large sandstone slab, pan of the R-horizon that is exposed around the margins of Leaning Rock. was unearthed during prior landclearing activities and pushed up against a lonely pine tree on the northern margins of the site: consequently the nom de plume Leaning Rock

Exploring excited states of Pt(ii) diimine catecholates for photoinduced charge separation

The intense absorption in the red part of the visible range, and the presence of a lowest charge-transfer excited state, render Platinum(II) diimine catecholates potentially promising candidates for light-driven applications. Here, we test their potential as sensitisers in dye-sensitised solar cells and apply, for the first time, the sensitive method of photoacoustic calorimetry (PAC) to determine the efficiency of electron injection in the semiconductor from a photoexcited Pt(II) complex. Pt(II) catecholates containing 2,2′-bipyridine-4,4′-di-carboxylic acid (dcbpy) have been prepared from their parent iso-propyl ester derivatives, complexes of 2,2′-bipyridine-4,4′-di-C(O)OiPr, (COOiPr)2bpy, and their photophysical and electrochemical properties studied. Modifying diimine Pt(II) catecholates with carboxylic acid functionality has allowed for the anchoring of these complexes to thin film TiO2, where steric bulk of the complexes (3,5-ditBu-catechol vs. catechol) has been found to significantly influence the extent of monolayer surface coverage. Dye-sensitised solar cells using Pt(dcbpy)(tBu2Cat), 1a, and Pt(dcbpy)(pCat), 2a, as sensitisers, have been assembled, and photovoltaic measurements performed. The observed low, 0.02–0.07%, device efficiency of such DSSCs is attributed at least in part to the short excited state lifetime of the sensitisers, inherent to this class of complexes. The lifetime of the charge-transfer ML/LLCT excited state in Pt((COOiPr)2bpy)(3,5-di-tBu-catechol) was determined as 250 ps by picosecond time-resolved infrared spectroscopy, TRIR. The measured increase in device efficiency for 2a over 1a is consistent with a similar increase in the quantum yield of charge separation (where the complex acts as a donor and the semiconductor as an acceptor) determined by PAC, and is also proportional to the increased surface loading achieved with 2a. It is concluded that the relative efficiency of devices sensitised with these particular Pt(II) species is governed by the degree of surface coverage. Overall, this work demonstrates the use of Pt(diimine)(catecholate) complexes as potential photosensitizers in solar cells, and the first application of photoacoustic calorimetry to Pt(II) complexes in general

GABA(A) receptors containing (alpha)5 subunits in the CA1 and CA3 hippocampal fields regulate ethanol-motivated behaviors: an extended ethanol reward circuitry

GABA receptors within the mesolimbic circuitry have been proposed to play a role in regulating alcohol-seeking behaviors in the alcohol-preferring (P) rat. However, the precise GABA(A) receptor subunit(s) mediating the reinforcing properties of EtOH remains unknown. We examined the capacity of intrahippocampal infusions of an alpha5 subunit-selective ( approximately 75-fold) benzodiazepine (BDZ) inverse agonist [i.e., RY 023 (RY) (tert-butyl 8-(trimethylsilyl) acetylene-5,6-dihydro-5-methyl-6-oxo-4H-imidazo [1,5a] [1,4] benzodiazepine-3-carboxylate)] to alter lever pressing maintained by concurrent presentation of EtOH (10% v/v) and a saccharin solution (0.05% w/v). Bilateral (1.5-20 microgram) and unilateral (0.01-40 microgram) RY dose-dependently reduced EtOH-maintained responding, with saccharin-maintained responding being reduced only with the highest doses (e.g., 20 and 40 microgram). The competitive BDZ antagonist ZK 93426 (ZK) (7 microgram) reversed the RY-induced suppression on EtOH-maintained responding, confirming that the effect was mediated via the BDZ site on the GABA(A) receptor complex. Intrahippocampal modulation of the EtOH-maintained responding was site-specific; no antagonism by RY after intra-accumbens [nucleus accumbens (NACC)] and intraventral tegmental [ventral tegmental area (VTA)] infusions was observed. Because the VTA and NACC contain very high densities of alpha1 and alpha2 subunits, respectively, we determined whether RY exhibited a "negative" or "neutral" pharmacological profile at recombinant alpha1beta3gamma2, alpha2beta3gamma2, and alpha5beta3gamma2 receptors expressed in Xenopus oocytes. RY produced "classic" inverse agonism at all alpha receptor subtypes; thus, a neutral efficacy was not sufficient to explain the failure of RY to alter EtOH responding in the NACC or VTA. The results provide the first demonstration that the alpha5-containing GABA(A) receptors in the hippocampus play an important role in regulating EtOH-seeking behaviors

Lithium Therapy Improves Neurological Function and Hippocampal Dendritic Arborization in a Spinocerebellar Ataxia Type 1 Mouse Model

Huda Zoghbi and colleagues show that lithium treatment initiated before or after disease onset improves multiple symptoms of neurodegeneration in a mouse model of spinocerebellar ataxia

Genetic association study of QT interval highlights role for calcium signaling pathways in myocardial repolarization.

The QT interval, an electrocardiographic measure reflecting myocardial repolarization, is a heritable trait. QT prolongation is a risk factor for ventricular arrhythmias and sudden cardiac death (SCD) and could indicate the presence of the potentially lethal mendelian long-QT syndrome (LQTS). Using a genome-wide association and replication study in up to 100,000 individuals, we identified 35 common variant loci associated with QT interval that collectively explain ∼8-10% of QT-interval variation and highlight the importance of calcium regulation in myocardial repolarization. Rare variant analysis of 6 new QT interval-associated loci in 298 unrelated probands with LQTS identified coding variants not found in controls but of uncertain causality and therefore requiring validation. Several newly identified loci encode proteins that physically interact with other recognized repolarization proteins. Our integration of common variant association, expression and orthogonal protein-protein interaction screens provides new insights into cardiac electrophysiology and identifies new candidate genes for ventricular arrhythmias, LQTS and SCD

In Vivo Generation of Neurotoxic Prion Protein: Role for Hsp70 in Accumulation of Misfolded Isoforms

Prion diseases are incurable neurodegenerative disorders in which the normal cellular prion protein (PrPC) converts into a misfolded isoform (PrPSc) with unique biochemical and structural properties that correlate with disease. In humans, prion disorders, such as Creutzfeldt-Jakob disease, present typically with a sporadic origin, where unknown mechanisms lead to the spontaneous misfolding and deposition of wild type PrP. To shed light on how wild-type PrP undergoes conformational changes and which are the cellular components involved in this process, we analyzed the dynamics of wild-type PrP from hamster in transgenic flies. In young flies, PrP demonstrates properties of the benign PrPC; in older flies, PrP misfolds, acquires biochemical and structural properties of PrPSc, and induces spongiform degeneration of brain neurons. Aged flies accumulate insoluble PrP that resists high concentrations of denaturing agents and contains PrPSc-specific conformational epitopes. In contrast to PrPSc from mammals, PrP is proteinase-sensitive in flies. Thus, wild-type PrP rapidly converts in vivo into a neurotoxic, protease-sensitive isoform distinct from prototypical PrPSc. Next, we investigated the role of molecular chaperones in PrP misfolding in vivo. Remarkably, Hsp70 prevents the accumulation of PrPSc-like conformers and protects against PrP-dependent neurodegeneration. This protective activity involves the direct interaction between Hsp70 and PrP, which may occur in active membrane microdomains such as lipid rafts, where we detected Hsp70. These results highlight the ability of wild-type PrP to spontaneously convert in vivo into a protease-sensitive isoform that is neurotoxic, supporting the idea that protease-resistant PrPSc is not required for pathology. Moreover, we identify a new role for Hsp70 in the accumulation of misfolded PrP. Overall, we provide new insight into the mechanisms of spontaneous accumulation of neurotoxic PrP and uncover the potential therapeutic role of Hsp70 in treating these devastating disorders