Fractional Stokes-Einstein and Debye-Stokes-Einstein relations in a network forming liquid

We study the breakdown of the Stokes-Einstein (SE) and Debye-Stokes-Einstein (DSE) relations for translational and rotational motion in a prototypical model of a network-forming liquid, the ST2 model of water. We find that the emergence of ``fractional'' SE and DSE relations at low temperature is ubiquitous in this system, with exponents that vary little over a range of distinct physical regimes. We also show that the same fractional SE relation is obeyed by both mobile and immobile dynamical heterogeneities of the liquid

Self-Efficacy and Post-Secondary First-Term Student Achievement

Generalized self-efficacy is the overall belief in one’s ability and Specific self-efficacy is task related. The study examined the extent and manner in which self-efficacy explains variation in first-term GPA. The General Self-Efficacy Scale was adapted and used with a sample of N = 194 students (34% male and 66% female) enrolled in a for-profit career education urban college. The data from two factors derived using an exploratory factor analysis, General self-efficacy and Specific self-efficacy, had alpha reliabilities of .73 and .75, respectively. General self-efficacy was correlated r = .18 with GPA and multiple regression analysis demonstrated that General incremented the explanation of variance 5% in GPA (p \u3c .01). Specific correlated r = .17 with GPA (p \u3c .05). General and Specific were significantly correlated (r = .42, p \u3c .001). The two independent variables were equal predictors of success

The Relationship of Self-Efficacy with GPA, Attendance, and College Student Retention

The purpose of this study was to examine the relationship between self-efficacy or belief in one’s capability (Bandura 1977b, 1986, 1993, 1997) and first-term GPA, attendance, and retention using a modified version of the General Self-Efficacy Scale (GSE) (Schwarzer, 1992, 1993, 2005; Schwarzer & Jerusalem, 1993). The study “College” is part of one of the world’s largest for-profit career education organizations. At the College, 100% of the students commute to classes and live in the metropolitan area. A large percentage of students live in difficult urban neighborhoods and grow up with low family income, abuse, gang violence, drugs, health problems, poor English, and academic underachievement. A study of student responsibility indicated that 54% of community college students are under the age of 25 and are not prepared academically or psychologically for what will be expected (Howell, 2001). They work to support dependents, frequently require childcare assistance, question their academic ability and perceive teachers as experts who dispense information and wisdom, and are frequently first-generation students. First-term student success at the College is measured by academic achievement (a required minimum GPA of 1.5 on a scale of 0 to 4.0). Many students receive formal academic warnings at the end of their first term because of poor academic performance in terms of GPA (1.5-2.0) or are involuntarily withdrawn for a GPA less than 1.5. The College has an open-admissions policy. Only a high school diploma or a GED is required for entry. Admissions representatives have a quota of students to recruit each term. Consequently, admission standards are flexible, as would be expected in a for-profit college. In this business context, being able to predict those students likely to earn a GPA of 1.5, consistently attend classes, and return for the next term translates into institutional success because continuing students generate future cash flow and profitability. The educational issue is being able to identify those students who need academic support to succeed. The purpose of this study was to determine if the construct of self-efficacy (Bandura 1977b, 1986, 1993, 1997) can predict student success and identify “at risk” students at the start of their first term at the College

Is the Compact Source at the Center of Cas A Pulsed?

A 50 ksec observation of the Supernova Remnant Cas A was taken using the Chandra X-Ray Observatory High Resolution Camera (HRC) to search for periodic signals from the compact source located near the center. Using the HRC-S in imaging mode, problems with correctly assigning times to events were overcome, allowing the period search to be extended to higher frequencies than possible with previous observations. In an extensive analysis of the HRC data, several possible candidate signals are found using various algorithms, including advanced techniques developed by Ransom to search for low significance periodic signals. Of the candidate periods, none is at a high enough confidence level to be particularly favored over the rest. When combined with other information, however (e.g., spectra, total energetics, and the historical age of the remnant), a 12 ms candidate period seems to be more physically plausible than the others, and we use it for illustrative purposes in discussing the possible properties of a putative neutron star in the remnant. We emphasize that this is not necessarily the true period, and that a follow-up observation, scheduled for the fall of 2001, is required. A 50 ksec Advanced CCD Imaging Spectrometer (ACIS) observation was taken, and analysis of these data for the central object shows that the spectrum is consistent with several forms, and that the emitted X-ray luminosity in the 0.1 -10 keV band is 10^{33}-10^{35}erg cm^{-2}sec^{-1} depending on the spectral model and the interstellar absorption along the line of sight to the source.Comment: 14 pages, 3 figures Submitted to ApJ 2001 June 2

Academic Motivation Decreases Across Adolescence for Youth With and Without Attention-Deficit/Hyperactivity Disorder: Effects of Motivation on Academic Success

This longitudinal study examined growth trajectories of academic motivation in youth with and without attention-deficit/hyperactivity disorder (ADHD) across the important developmental transition from middle school to high school, and associations with academic success. Consistent with self-determination theory (SDT) of motivation, trajectories of amotivation, extrinsic motivation, and intrinsic motivation were modeled

Practice characteristics of Emergency Department extracorporeal cardiopulmonary resuscitation (eCPR) programs in the United States: The current state of the art of Emergency Department extracorporeal membrane oxygenation (ED ECMO).

PURPOSE: To characterize the current scope and practices of centers performing extracorporeal cardiopulmonary resuscitation (eCPR) on the undifferentiated patient with cardiac arrest in the emergency department. METHODS: We contacted all US centers in January 2016 that had submitted adult eCPR cases to the Extracorporeal Life Support Organization (ELSO) registry and surveyed them, querying for programs that had performed eCPR in the Emergency Department (ED ECMO). Our objective was to characterize the following domains of ED ECMO practice: program characteristics, patient selection, devices and techniques, and personnel. RESULTS: Among 99 centers queried, 70 responded. Among these, 36 centers performed ED ECMO. Nearly 93% of programs are based at academic/teaching hospitals. 65% of programs are less than 5 years old, and 60% of programs perform ≤3 cases per year. Most programs (90%) had inpatient eCPR or salvage ECMO programs prior to starting ED ECMO programs. The majority of programs do not have formal inclusion and exclusion criteria. Most programs preferentially obtain vascular access via the percutaneous route (70%) and many (40%) use mechanical CPR during cannulation. The most commonly used console is the Maquet Rotaflow(®). Cannulation is most often performed by cardiothoracic (CT) surgery, and nearly all programs (\u3e85%) involve CT surgeons, perfusionists, and pharmacists. CONCLUSIONS: Over a third of centers that submitted adult eCPR cases to ELSO have performed ED ECMO. These programs are largely based at academic hospitals, new, and have low volumes. They do not have many formal inclusion or exclusion criteria, and devices and techniques are variable

Chandra Phase-Resolved Spectroscopy of the Crab Pulsar

We present the first phase-resolved study of the X-ray spectral properties of the Crab Pulsar that covers all pulse phases. The superb angular resolution of the Chandra X-ray Observatory enables distinguishing the pulsar from the surrounding nebulosity, even at pulse minimum. Analysis of the pulse-averaged spectrum measures interstellar X-ray extinction due primarily to photoelectric absorption and secondarily to scattering by dust grains in the direction of the Crab Nebula. We confirm previous findings that the line-of-sight to the Crab is underabundant in oxygen, although more-so than recently measured. Using the abundances and cross sections from Wilms, Allen & McCray (2000) we find [O/H] = (3.33 +/-0.25) x 10**-4. Analysis of the spectrum as a function of pulse phase measures the low-energy X-ray spectral index even at pulse minimum -- albeit with large statistical uncertainty -- and we find marginal evidence for variations of the spectral index. The data are also used to set a new (3-sigma) upper limit to the temperature of the neutron star of log T(infinity) < 6.30.Comment: 20 Pages including 7 figures. Accepted for publication in the Astrophysical Journa

Protein/Protein Interactions in the Mammalian Heme Degradation Pathway: Heme Oxygenase-2, Cytochrome P450 Reductase, and Biliverdin Reductase

Heme oxygenase (HO) catalyzes the rate-limiting step in the O2- dependent degradation of heme to biliverdin, CO, and iron with electrons delivered from NADPH via cytochrome P450 reductase (CPR). Biliverdin reductase (BVR) then catalyzes conversion of bili­verdin to bilirubin. We describe mutagenesis combined with kinetic, spectroscopic (fluorescence and NMR), surface plasmon resonance, cross-linking, gel filtration, and analytical ultracentrifugation studies aimed at evaluating interactions of HO-2 with CPR and BVR. Based on these results, we propose a model in which HO-2 and CPR form a dynamic ensemble of complex(es) that precede formation of the productive electron transfer complex. The 1H-15N TROSY NMR spectrum of HO-2 reveals specific residues, including Leu-201, near the heme face of HO-2 that are affected by the addition of CPR, im­plicating these residues at the HO/CPR interface. Alanine substitu­tions at HO-2 residues Leu-201 and Lys-169 cause a respective 3- and 22-fold increase in Km values for CPR, consistent with a role for these residues in CPR binding. Sedimentation velocity experiments confirm the transient nature of the HO-2·CPR complex (Kd = 15.1 μm). Our results also indicate that HO-2 and BVR form a very weak complex that is only captured by cross-linking. For example, under conditions where CPR affects the 1H-15N TROSY NMR spectrum of HO-2, BVR has no effect. Fluorescence quenching experiments also suggest that BVR binds HO-2 weakly, if at all, and that the previously reported high affinity of BVR for HO is artifactual, resulting from the effects of free heme (dissociated from HO) on BVR fluorescenc

Protein/Protein Interactions in the Mammalian Heme Degradation Pathway: Heme Oxygenase-2, Cytochrome P450 Reductase, and Biliverdin Reductase

Heme oxygenase (HO) catalyzes the rate-limiting step in the O2- dependent degradation of heme to biliverdin, CO, and iron with electrons delivered from NADPH via cytochrome P450 reductase (CPR). Biliverdin reductase (BVR) then catalyzes conversion of bili­verdin to bilirubin. We describe mutagenesis combined with kinetic, spectroscopic (fluorescence and NMR), surface plasmon resonance, cross-linking, gel filtration, and analytical ultracentrifugation studies aimed at evaluating interactions of HO-2 with CPR and BVR. Based on these results, we propose a model in which HO-2 and CPR form a dynamic ensemble of complex(es) that precede formation of the productive electron transfer complex. The 1H-15N TROSY NMR spectrum of HO-2 reveals specific residues, including Leu-201, near the heme face of HO-2 that are affected by the addition of CPR, im­plicating these residues at the HO/CPR interface. Alanine substitu­tions at HO-2 residues Leu-201 and Lys-169 cause a respective 3- and 22-fold increase in Km values for CPR, consistent with a role for these residues in CPR binding. Sedimentation velocity experiments confirm the transient nature of the HO-2·CPR complex (Kd = 15.1 μm). Our results also indicate that HO-2 and BVR form a very weak complex that is only captured by cross-linking. For example, under conditions where CPR affects the 1H-15N TROSY NMR spectrum of HO-2, BVR has no effect. Fluorescence quenching experiments also suggest that BVR binds HO-2 weakly, if at all, and that the previously reported high affinity of BVR for HO is artifactual, resulting from the effects of free heme (dissociated from HO) on BVR fluorescenc