Doctoral Program Design Based on Technology-Based Situated Learning and Mentoring: A Comparison of Part-Time and Full-Time Doctoral Students

Aim/Purpose Most programs are designed with full-time doctoral students\u27 characteristics and needs in mind; few programs consider the unique needs of part-time doctoral students, including time restrictions, experiences during the program, identity development, and different professional aspirations. The purpose of this study was to evaluate the potential differences between part-time and full-time doctoral students in their scholarly development, and how technology may serve as a communication and organization tool for individual and program support. Background Built on the application of communities of practice, information and communication technology, and situated learning theory, this study sought to evaluate the potential differences among full-time and part-time doctoral students associated with their scholarly development in a traditional doctoral program at a large research-intensive university. Methodology This study used independent samples t-test to evaluate the potential differences between part-time and full-time doctoral students in their scholarly development. Data were collected from 98 doctoral students via a survey. This study also employed two hypothetical cases that described the issues and solutions related to the program pursuant to scholarly development, which further illustrated the quantitative results and provided more meaningful discussions and suggestions. Contribution This study provided insights into part-time doctoral students\u27 scholarly development and provided suggestions for designing doctoral programs and differentiated mentoring for both full-time and part-time doctoral students. Further, additional multifaceted mentoring approaches including peer mentoring and e-mentoring were evaluated. Findings Significant differences were found in four aspects of doctoral students\u27 scholarly development: the opportunities to do research related to grants with faculty, support for scholarly work in addition to advisor\u27s support, involvement in the teaching/supervision activities, and goals for scholarly development. Recommendations Program designers, faculty, and especially mentors should appreciate the diffor Practitioners ferences between part-time and full-time doctoral students. Potential program redesigns should include judicious applications of technology as essential components to address limited accessibility and opportunities for part-time students. An Individual Development Plan (IDP) should be used to mentor doctoral students to enhance the effectiveness of mentoring regarding academic goals, actions, and related roles and responsibilities. Recommendations Future research can further evaluate and develop the instrument to better for Researchers measure more domains of doctoral students\u27 scholarly development. Additionally, qualitative methods may be used to further provide the emic description of the process of part-time students\u27 engagement with the program, mentors, and peers. Impact on Society With consideration of the unique needs of part-time students and the application of technology-based learning community, opportunities are provided for mentors and doctoral students to engage in scholarship and develop a sense of belonging to their doctoral program. Future Research Future research can examine the differences between male and female doctoral students, different race groups, and disciplines

Treatment of diabetic retinopathy through neuropeptide Y-mediated enhancement of neurovascular microenvironment

Diabetic retinopathy (DR) is one of the most severe clinical manifestations of diabetes mellitus and a major cause of blindness. DR is principally a microvascular disease, although the pathogenesis also involves metabolic reactive intermediates which induce neuronal and glial activation resulting in disruption of the neurovascular unit and regulation of the microvasculature. However, the impact of neural/glial activation in DR remains controversial, notwithstanding our understanding as to when neural/glial activation occurs in the course of disease. The objective of this study was to determine a potential protective role of neuropeptide Y (NPY) using an established model of DR permissive to N‐methyl‐D‐aspartate (NMDA)‐induced excitotoxic apoptosis of retinal ganglion cells (RGC) and vascular endothelial growth factor (VEGF)‐induced vascular leakage. In vitro evaluation using primary retinal endothelial cells demonstrates that NPY promotes vascular integrity, demonstrated by maintained tight junction protein expression and reduced permeability in response to VEGF treatment. Furthermore, ex vivo assessment of retinal tissue explants shows that NPY can protect RGC from excitotoxic‐induced apoptosis. In vivo clinical imaging and ex vivo tissue analysis in the diabetic model permitted assessment of NPY treatment in relation to neural and endothelial changes. The neuroprotective effects of NPY were confirmed by attenuating NMDA‐induced retinal neural apoptosis and able to maintain inner retinal vascular integrity. These findings could have important clinical implications and offer novel therapeutic approaches for the treatment in the early stages of DR

Circumstellar dust as a solution to the red supergiant supernova progenitor problem

We investigate the red supergiant problem: the apparent dearth of Type IIP supernova progenitors with masses between 16 and 30 M_sun. Although red supergiants with masses in this range have been observed, none have been identified as progenitors in pre-explosion images. We show that by failing to take into account the additional extinction resulting from the dust produced in the red supergiant winds, we risk underestimating the luminosity of the most massive red supergiants at the end of their lives. We estimate the initial masses of all Type IIP progenitors for which observations exist and analyse the resulting population. We find that the most likely maximum mass for a Type IIP progenitor is 21^{+2}_{-1} M_sun. This is in closer agreement with the limit predicted from single star evolution models.Comment: 10 pages, 6 figures and 4 tables. Accepted for publication in MNRA

Positron and positronium affinities in the work-formalism Hartree-Fock approximation

Positron binding to anions is investigated within the work formalism proposed by Harbola and Sahni for the halide anions and the systems Li^- through O^- excluding Be^- and N^-. The toal ground-state energies of the anion-positron bound systems are empirically found to be an upper bound to the Hartree-Fock energies. The computed expectation values as well as positron and positronium affinities are in good agreement with their restricted Hartree-Fock counterparts. Binding of a positron to neutral species is also investigated using an iterative method.Comment: 12 pages, to appear in Physical Review

Giant peroxisomes in a moss (Physcomitrella patens) peroxisomal biogenesis factor 11 mutant

Peroxisomal biogenesis factor 11 (PEX11) proteins are found in yeasts, mammals and plants, and play a role in peroxisome morphology and regulation of peroxisome division. The moss Physcomitrella patens has six PEX11 isoforms which fall into two subfamilies, similar to those found in monocots and dicots. We carried out targeted gene disruption of the Phypa_PEX11-1 gene and compared the morphological and cellular phenotypes of the wild-type and mutant strains. The mutant grew more slowly and the development of gametophores was retarded. Mutant chloronemal filaments contained large cellular structures which excluded all other cellular organelles. Expression of fluorescent reporter proteins revealed that the mutant strain had greatly enlarged peroxisomes up to 10 μm in diameter. Expression of a vacuolar membrane marker confirmed that the enlarged structures were not vacuoles, or peroxisomes sequestered within vacuoles as a result of pexophagy. Phypa_PEX11 targeted to peroxisome membranes could rescue the knock out phenotype and interacted with Fission1 on the peroxisome membrane. Moss PEX11 functions in peroxisome division similar to PEX11 in other organisms but the mutant phenotype is more extreme and environmentally determined, making P. patens a powerful system in which to address mechanisms of peroxisome proliferation and division

Bis(N-methyl-N-phenyl­carbamo­yl)disulfane

The title compound, C16H16N2O2S2, has been synthesized by several different high-yield routes, and has been encountered as a co-product in a number of reaction pathways, ever since it became of inter­est to our research program over 30 years ago. We now confirm the proposed mol­ecular structure in which the mol­ecule exhibits a twofold axis of symmetry through the mid-point of the S—S bond and the two planes defined by the (carbamo­yl)sulfenyl moieties are essentially perpendicular to each other [dihedral angle = 81.55 (14)°]

A Swift survey of accretion onto stellar-mass black holes

We present a systemic analysis of all of the stellar mass black hole binaries (confirmed & candidate) observed by the Swift observatory up to June 2010. The broad Swift bandpass enables a trace of disk evolution over an unprecedented range in flux and temperature. The final data sample consists of 476 X-ray spectra containing greater than 100 counts, in the 0.6 -- 10 keV band. This is the largest sample of high quality CCD spectra of accreting black holes published to date. In addition, strictly simultaneous data at optical/UV wavelengths are available for 255 (54%) of these observations. The data are modelled with a combination of an accretion disk and a hard spectral component. For the hard component we consider both a simple power-law and a thermal Comptonization model. An accretion disk is detected at greater than the 5sigma confidence level in 61% of the observations. Lightcurves and color-color diagrams are constructed for each system. Hardness luminosity and disk fraction luminosity diagrams are constructed and are observed to be consistent with those typically observed by RXTE, noting the sensitivity below 2 keV provided by Swift. The observed spectra have an average luminosity of ~ 1% Eddington, though we are sensitive to accretion disks down to a luminosity of 10^{-3} L_Edd. Thus this is also the largest sample of such cool accretion disks studied to date. (abridged)Comment: 28 pages, 5 tables, 21 figures, Accepted for publication in ApJ. This is the final revised versio

Analytical, Optimal, and Sparse Optimal Control of Traveling Wave Solutions to Reaction-Diffusion Systems

This work deals with the position control of selected patterns in reaction-diffusion systems. Exemplarily, the Schl\"{o}gl and FitzHugh-Nagumo model are discussed using three different approaches. First, an analytical solution is proposed. Second, the standard optimal control procedure is applied. The third approach extends standard optimal control to so-called sparse optimal control that results in very localized control signals and allows the analysis of second order optimality conditions.Comment: 22 pages, 3 figures, 2 table

Nonintrusive tracing in the Internet

Intruders that log in through a series of machines when conducting an attack are hard to trace because of the complex architecture of the Internet. The thumbprinting method provides an efficient way of tracing such intruders by determining whether two connections are part of the same connection chain. Because many connections are transient and therefore short in length, choosing the best time interval to thumbprint over can be an issue. In this paper, we provide a way to shorten the time interval used for thumbprinting. We then study some special properties of the thumbprinting function. We also study another mechanism for tracing intruders in the Internet based on a timestamping approach, which passively monitors flows between source and destination pairs. Given a potentially suspicious source, we identify its true destination. We compute the error probability of our algorithm and show that its value decreases exponentially as the observation time increases. Our simulation results show that our approach performs well