1,131 research outputs found
Deterritorializing Dichotomies in Teacher Induction: A (Post)Ethnographic Study of Un/Becoming an Elementary Science Teacher
Un/becoming an elementary science teacher is a dynamic phenomenon, yet the process is often intentionally limited to several taken-for-granted assumptions in research on science teacher induction. Inherent to research on beginning science teacher induction is also the construction of certain truths beginning science teachers, science teacher educators, and researchers think, feel, and live. This study complicates prevailing truths shaping notions of beginner, novice, induction, and traditions of inquiry as an ethicopolitical commitment to those implicated. In doing so, this study illuminates more expansive ways science teacher educators and those studying induction might study and understand the experiences of beginning science teachers from both humanist and post-humanist ontological paradigms. To provide an intimate, in-depth, and multidimensional analysis of elementary science teacher induction experiences, feminist post-structural theory was employed throughout the study. This perspective further informed the post-foundational ethnographic practices shaping the structure of the study as an always-already emergent process. Taking form as a (post)ethnographic inquiry, the study specifically examined the induction experiences of two beginning elementary science teachers alongside three ontological dichotomies in research shaping science teacher induction: (a) the beginning science teacher subject; (b) the concept of induction; and (c) the mode of inquiry. Employing both conventional humanist qualitative methods and post-qualitative inquiry, this study reveals the multifaceted ways in which beginning elementary science teacher subjectivity, research assumptions, and definitions framing the very notion of elementary science teacher induction intra-act. Offering a series of provocations as lines of flight, researchers of science teacher induction and science teacher educators might begin to re-conceptualize ways beginning science teachers un/become known and get re/produced
The socio-cultural perceptions of food habits, body image and obesity of black-American women in Columbia, Missouri
Title from PDF of title page (University of Missouri--Columbia, viewed on March 7, 2011).The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file.Dissertation advisor: Dr. Rex Campbell.Vita.Ph. D. University of Missouri--Columbia 2010.Obesity as a growing epidemic in the United States occurs in higher rates within Black-American populations. Although 100 million Americans in the United States are considered overweight or obese, Black-American women have the highest prevalence rate of obesity than any other subgroup. Most studies focus on unhealthy eating practices, lack of exercise, sedentary lifestyles, differential access to nutritious food and lack of adequate health care as contributors of obesity in Black-American women. But these studies are narrow in approach, lacking cultural constructions and food habits pertinent to the history and biography of Black-Americans. This dissertation explores Black women's perceptions of black culture, food habits, body image and obesity in Columbia, Missouri. This dissertation is theoretically rooted in the tradition of symbolic interaction, which is best suited to explore the culturally derived ritualistic behaviors and traditions within Black Culture. By investigating food habits and cooking practices as symbolic manifestations, direct associations to the development of self, identity and in-group ethnic affiliation emerges. This research uses narratives from 15 in-depth interviews, compiled over a two year period. Results indicate black women's perceptions of self, identity, food habits, and body image was socio-cultural constructions. When holistically viewed, insights provided rich interpretations of one's life experiences and interactions within the groups' cultural milieu.Includes bibliographical reference
Searching for proto-brown dwarfs: Extending near IR spectroscopy of protostars below the hydrogen burning limit
Recent observations of nearby star forming regions have offered evidence that
young brown dwarfs undergo a period of mass accretion analogous to the T Tauri
phase observed in young stars. Brown dwarf analogs to stellar protostars,
however, have yet to be definitively observed. These young, accreting objects
would shed light on the nature of the dominant brown dwarf formation process,
as well as provide ideal laboratories to investigate the dependence of the
accretion mechanism on protostellar mass. Recent near infrared surveys have
identified candidate proto-brown dwarfs and characterized low mass protostars
in nearby star forming regions. These techniques allow near infrared spectra to
diagnose the effective temperature, accretion luminosity, magnetic field
strength and rotation velocity of young low mass stars across the
stellar/substellar boundary. The lowest mass proto-brown dwarfs (M < 40 M_Jup),
however, will prove challenging to observe given current near IR observational
capabilities.Comment: 6 pages, 4 figures. Submitted to Astronomical Notes for the special
issue containing the proceedings of the "Ultra low-mass star formation and
evolution" worksho
Probing the embedded YSOs of the R CrA region through VLT-ISAAC spectroscopy
Near IR spectra obtained with ISAAC at VLT, have been used to pose
constraints on the evolutionary state and accretion properties of a sample of
five embedded YSOs located in the R CrA core. This sample includes three Class
I sources (HH100 IR, IRS2 and IRS5), and two sources with NIR excesses (IRS6
and IRS3). Absorption lines have been detected in the medium resolution spectra
of all the observed targets, together with emission lines likely originating in
the disk-star-wind connected regions. We derived spectral types, veiling and
stellar luminosity of the five observed sources, which in turn have been used
to infer their mass and age adopting pre-main sequence evolutionary tracks. We
find that in HH100 IR and IRS2 most of the bolometric luminosity is due to
accretion, while the other three investigated sources, including the Class I
object IRS5a, present a low accretion activity (L_{acc}/L_{bol} < 0.2). We
observe a general correlation between the accretion luminosity, the IR veiling
and the emission line activity of the sources. A correlation between the
accretion activity and the spectral energy distribution slope is recognizable
but with the notable exception of IRS5a. Our analysis therefore shows how the
definition of the evolutionary stage of deeply embedded YSOs by means of IR
colors needs to be more carefully refined.Comment: 17 pages, 13 figures, accepted on A&
A Search for "Dwarf" Seyfert Nuclei. VII. A Catalog of Central Stellar Velocity Dispersions of Nearby Galaxies
We present new central stellar velocity dispersion measurements for 428 galaxies in the Palomar spectroscopic survey of bright, northern galaxies. Of these, 142 have no previously published measurements, most being relatively late-type systems with low velocity dispersions (âŸ100 km s^(â1)). We provide updates to a number of literature dispersions with large uncertainties. Our measurements are based on a direct pixel-fitting technique that can accommodate composite stellar populations by calculating an optimal linear combination of input stellar templates. The original Palomar survey data were taken under conditions that are not ideally suited for deriving stellar velocity dispersions for galaxies with a wide range of Hubble types. We describe an effective strategy to circumvent this complication and demonstrate that we can still obtain reliable velocity dispersions for this sample of well-studied nearby galaxies
Near-infrared spectra of ISO selected Chamaeleon I young stellar objects
We present 0.95--2.5 micron moderate (R = 500) resolution spectra of 19
ISOCAM detected sources in the Chamaeleon I dark cloud. Thirteen of these stars
are candidate very low mass members of the cloud proposed by Persi et al. (2000
A&A 357:219) on basis of the mid-IR color excess. The sample also includes a
bona-fide young brown dwarf (Cha Halpha 1), a transition
--stellar/sub-stellar-- object (Cha Halpha 2), one previously known T Tauri
star (Sz 33) and three ISOCAM sources with no mid-IR excess. The spectra of the
mid-IR color excess sources are relatively flat and featureless in this
wavelength range. Both atomic and molecular lines (when in absorption) are
partially veiled suggesting the presence of continuum emission from
circumstellar dust. In addition some of the sources show Paschen and Brackett
lines in emission. We apply the 2 micron water vapor index defined by Wilking
et al. (1999 AJ 117:469) to estimate spectral types. These stars have spectral
types M0--8. We use Persi et al.'s stellar luminosity determinations, in
combination with D'Antona & Mazzitelli latest pre-main sequence evolutionary
tracks, to estimate masses and ages. The ISOCAM detected mid-IR excess sources
have sub-solar masses down to the H-burning limit and a median age of few x
10^6 yr, in good agreement with the higher mass members of this cloud.Comment: Preprint in Manuscript format; 30 pages including 10 figure
Bacillus Coagulans GBI-30 (BC30) improves indices of Clostridium difficile-Induced colitis in mice
<p>Abstract</p> <p>Background</p> <p>Probiotics have beneficial effects in rodent models of <it>Clostridium difficile </it>(<it>C. diffiicle</it>)-induced colitis. The spore forming probiotic strain <it>Bacillus Coagulans </it>GBI-30, 6086 (BC30) has demonstrated anti-inflammatory and immune-modulating effects <it>in vitro</it>. Our goal was to determine if BC30 improved <it>C. difficile</it>-induced colitis in mice. Starting on study day 0, female C57BL/6 mice were dosed by oro-gastric gavage for 15 days with vehicle (saline) or BC30 (2 à 10<sup>9 </sup>CFU per day). Mice in the <it>C. difficile </it>groups received an antibiotic mixture (study days 5 to 8 in the drinking water), and clindamycin (10 mg/kg, i.p., on study day 10). The <it>C. difficile </it>strain VPI 10463 was given by gavage at 10<sup>4 </sup>CFU to induce colitis on day 11. On day 16, stools and colons were collected for further analyses.</p> <p>Results</p> <p>All mice treated with BC30 survived on study day 13, while two mice treated with vehicle did not survive. On day 12, a significant difference (p = 0.0002) in the percentage of mice with normal stools (66.7%) was found in the BC30/<it>C. difficile </it>group, as compared to the vehicle/<it>C. diffcile </it>group (13.0%). On study day 16, 23.8% of mice treated with BC30 had normal stools, while this value was 0% with vehicle treatment (p value = 0.0187). On this day, the stool consistency score for the BC30/<it>C. difficile </it>group (1.1 ± 0.2) was significantly lower (p < 0.05) than for the vehicle/<it>C. difficile </it>cohort (1.9 ± 0.2). BC30 modestly attenuated the colonic pathology (crypt damage, edema, leukocyte influx) that was present following <it>C. difficile infection</it>. Colonic MIP-2 chemokine contents (pg/2 cm colon) were: 10.2 ± 0.5 (vehicle/no <it>C. difficile</it>), 24.6 ± 9.5 (vehicle/<it>C. difficile</it>) and 16.3 ± 4.3 (BC30/<it>C. difficle</it>).</p> <p>Conclusion</p> <p>The probiotic BC30 improved some parameters of <it>C. difficile</it>-induced colitis in mice. BC30 prolonged the survival of <it>C. diffiicle </it>infected mice. Particularly, this probiotic improved the stool consistency of mice, in this infectious colitis model.</p
Telemedicine in the Emergency Department in the Era of COVID-19: Front-Line Experiences from 2 Institutions
During the COVID-19 pandemic, one of the major changes that has occurred in emergency medicine is the evolution of telemedicine. With relaxation of regulatory and administrative barriers, the use of this already available technology has rapidly expanded. Telemedicine provides opportunity to markedly decrease personal protective equipment (PPE) and reduce healthcare worker exposures. Moreover, with the convenience and availability of access to medical care via telemedicine, a more fundamental change in healthcare delivery in the United States is likely. The implementation of telemedicine in the emergency department (ED) in particular has great potential to prevent the iatrogenic spread of COVID-19 and protect health care workers. Challenges to widespread adoption of telemedicine include privacy concerns, limitation of physical examination, and concerns of patient experience. In this clinical review, we discuss ED telemedicine applications, logistics, and challenges in the COVID-19 era as well as recent regulatory and legal changes. In addition, examples of telemedicine use are described from 2 institutions. Examples of future applications of telemedicine within the realm of emergency medicine are also discussed
Accretion in the Rho-Oph pre-main sequence stars
The aim of this paper is to provide a measurement of the mass accretion rate
in a large, complete sample of objects in the core of the star forming region
Rho-Oph. The sample includes most of the objects (104 out of 111) with evidence
of a circumstellar disk from mid-infrared photometry; it covers a stellar mass
range from about 0.03 to 3 Msun and it is complete to a limiting mass of ~0.05
Msun. We used J and K-band spectra to derive the mass accretion rate of each
object from the intensity of the hydrogen recombination lines, Pab or Brg. For
comparison, we also obtained similar spectra of 35 diskless objects. The
results show that emission in these lines is only seen in stars with disks, and
can be used as an indicator of accretion. However, the converse does not hold,
as about 50% of our disk objects do not have detectable line emission. The
measured accretion rates show a strong correlation with the mass of the central
object (Macc ~ Mstar^1.8+-0.2) and a large spread, of two orders of magnitude
at least, for any interval of Mstar. A comparison with existing data for Taurus
shows that the objects in the two regions have similar behaviour, at least for
objects more massive than ~0.1Msun. The implications of these results are
briefly discussed.Comment: A&A in press, 16 pages including tables, 5 figure
Stochastic modelling, Bayesian inference, and new in vivo measurements elucidate the debated mtDNA bottleneck mechanism
Dangerous damage to mitochondrial DNA (mtDNA) can be ameliorated during
mammalian development through a highly debated mechanism called the mtDNA
bottleneck. Uncertainty surrounding this process limits our ability to address
inherited mtDNA diseases. We produce a new, physically motivated, generalisable
theoretical model for mtDNA populations during development, allowing the first
statistical comparison of proposed bottleneck mechanisms. Using approximate
Bayesian computation and mouse data, we find most statistical support for a
combination of binomial partitioning of mtDNAs at cell divisions and random
mtDNA turnover, meaning that the debated exact magnitude of mtDNA copy number
depletion is flexible. New experimental measurements from a wild-derived mtDNA
pairing in mice confirm the theoretical predictions of this model. We
analytically solve a mathematical description of this mechanism, computing
probabilities of mtDNA disease onset, efficacy of clinical sampling strategies,
and effects of potential dynamic interventions, thus developing a quantitative
and experimentally-supported stochastic theory of the bottleneck.Comment: Main text: 14 pages, 5 figures; Supplement: 17 pages, 4 figures;
Total: 31 pages, 9 figure
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