3,098 research outputs found
Modeling instruction: Positive attitudinal shifts in introductory physics measured with CLASS
Among the most surprising findings in Physics Education Research is the lack of positive results on attitudinal measures, such as Colorado Learning Attitudes about Science Survey (CLASS) and Maryland Physics Expectations Survey (MPEX). The uniformity with which physics teaching manages to negatively shift attitudes toward physics learning is striking. Strategies which have been shown to improve conceptual learning, such as interactive engagement and studio-format classes, provide more authentic science experiences for students; yet do not seem to be sufficient to produce positive attitudinal results. Florida International University’s Physics Education Research Group has implemented Modeling Instruction in University Physics classes as part of an overall effort toward building a research and learning community. Modeling Instruction is explicitly designed to engage students in scientific practices that include model building, validation, and revision. Results from a preinstruction/postinstruction CLASS measurement show attitudinal improvements through both semesters of an introductory physics sequence, as well as over the entire two-course sequence. In this Brief Report, we report positive shifts from the CLASS in one section of a modeling-based introductory physics sequence, for both mechanics (N=22) and electricity and magnetism (N=23). Using the CLASS results and follow up interviews, we examine how these results reflect on modeling instruction and the unique student community and population at FIU
Gloucester County Shoreline And Tidal Marsh Inventory
This inventory is intended to serve as a useful planning tool for managers, planners, regulators, and environmentalists with an interest in Gloucester County. This report documents conditions measured in the County of Gloucester using remote sensing techniques. Two separate activities have occurred in tandem to develop this inventory of tidal marsh, and shoreline features. First, a delineation of tidal marshes within the county used high end image processing software along with color infra-red imagery to delineate the boundaries oftidal marshes\u27within 33 georeferenced scenes. The process calculates the amount of tidal marsh measured within each river segment in acres. Second, the report illustrates results from an aerial survey to delineate the types of shoreline structures, and general conditions observed along the shore. Documentation describing the waterway segments has been edited from the earlier Tidal Marsh Inventory Report for Gloucester County. Frequent reference to the Marsh Types, as defined by the Virginia Marine Resources Commission and the Wetlands Advisory Program at VIMS, is noteworthy. Appendix 1 defmes these types. The report organizes the county into nine (9) river segments or waterways: the Poropotank River to Purtan Island, Purtan Bay to Sandy Creek, Jones Creek to Carmine Islands, Gloucester Point, Guinea, the Severn River, the Ware River, the North River, and the Piankatank River. Both shoreline features and tidal marshes are illustrated separately as a series of plates which divide the waterway into smaller segments. A composite image of the waterway segment is presented fust, followed by the larger scale plates at 1:24,000. A brief description of each segment precedes the plates, and presents information related to the composition of the marshes, and the general state of the shoreline. Appendix 2 defines some important terms found in these sections
Ariel - Volume 8 Number 1
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On the X-ray properties of submm-selected galaxies
We present an analysis of the X-ray properties of 35 submm galaxies(SMGs) in
the CDF-N. Using a sample of robust 850micron-selected galaxies, with accurate
positions from Spitzer and/or radio counterparts, we find 16 objects (45+/-8%)
with significant X-ray detections in the 2Ms Chandra data. 6 of these SMGs
(~17+/-6%) have measured X-ray luminosities or upper limits consistent with
those expected based on the far-infrared (FIR) or radio-derived star formation
rate (SFR), and hence with the X-rays coming solely from star formation. In
another 7 sources (20+/-7%) a dominant AGN contribution to the X-ray emission
is required, while in 3 more it is unclear whether stellar process or accretion
are responsible. Stacking of the X-ray undetected SMGs reveals a highly
significant detection. If due to star formation, this corresponds to an average
X-ray derived SFR of ~150 Msun/yr. We deduce that the AGN fraction in SMGs
based on X-ray observations is 20-29 (+/-7) %, which is towards the lower limit
of previous estimates. Spectral analysis shows that in general the SMGs are not
heavily obscured in the X-ray but most of the SMGs classfied as AGN show
absorption with N_H in excess of 10^22 cm^-2. Of the secure AGN, the bolometric
luminosity appears to be dominated by the AGN in only 3 cases. In ~85% of the
SMGs, the X-ray spectrum effectively rules out an AGN contribution that
dominates the bolometric emission, even if the AGN is Compton thick. The
evidence therefore suggests that intense star formation accounts for both the
FIR and X-ray emission in most SMGs. We argue that, rather than having an
especially high AGN fraction or duty cycle, SMGs have a high X-ray detection
rate at very faint fluxes partly because of their high star formation rates
and, in rarer cases, because the submm emission is from an AGN.(abridged)Comment: 12 pages, 5 figures, accepted for publication in MNRA
The Disunity of Consciousness
It is commonplace for both philosophers and cognitive scientists to express their allegiance to the
"unity of consciousness". This is the claim that a subjectÂ’s phenomenal consciousness, at any one
moment in time, is a single thing. This view has had a major influence on computational theories
of consciousness. In particular, what we call single-track theories dominate the literature,
theories which contend that our conscious experience is the result of a single consciousness-making
process or mechanism in the brain. We argue that the orthodox view is quite wrong:
phenomenal experience is not a unity, in the sense of being a single thing at each instant. It is a
multiplicity, an aggregate of phenomenal elements, each of which is the product of a distinct
consciousness-making mechanism in the brain. Consequently, cognitive science is in need of a
multi-track theory of consciousness; a computational model that acknowledges both the
manifold nature of experience, and its distributed neural basis
Sensitivity and reproducibility of standardized-competitive RT-PCR for transcript quantification and its comparison with real time RT-PCR
BACKGROUND: Probe based detection assays form the mainstay of transcript quantification. Problems with these assays include varying hybridization efficiencies of the probes used for transcript quantification and the expense involved. We examined the ability of a standardized competitive RT-PCR (StaRT PCR) assay to quantify transcripts of 4 cell cycle associated genes (RB, E2F1, CDKN2A and PCNA) in two cell lines (T24 & LD419) and compared its efficacy with the established Taqman real time quantitative RT-PCR assay. We also assessed the sensitivity, reproducibility and consistency of StaRT PCR. StaRT PCR assay is based on the incorporation of competitive templates (CT) in precisely standardized quantities along with the native template (NT) in a PCR reaction. This enables transcript quantification by comparing the NT and CT band intensities at the end of the PCR amplification. The CT serves as an ideal internal control. The transcript numbers are expressed as copies per million transcripts of a control gene such as β-actin (ACTB). RESULTS: The NT and CT were amplified at remarkably similar rates throughout the StaRT PCR amplification cycles, and the coefficient of variation was least (<3.8%) when the NT/CT ratio was kept as close to 1:1 as possible. The variability between the rates of amplification in different tubes subjected to the same StaRT PCR reaction was very low and within the range of experimental noise. Further, StaRT PCR was sensitive enough to detect variations as low as 10% in endogenous actin transcript quantity (p < 0.01 by the paired student's t-test). StaRT PCR correlated well with Taqman real time RT-PCR assay in terms of transcript quantification efficacy (p < 0.01 for all 4 genes by the Spearman Rank correlation method) and the ability to discriminate between cell types and confluence patterns. CONCLUSION: StaRT PCR is thus a reliable and sensitive technique that can be applied to medium-high throughput quantitative transcript measurement. Further, it correlates well with Taqman real time PCR in terms of quantitative and discriminatory ability. This label-free, inexpensive technique may provide the ability to generate prognostically important molecular signatures unique to individual tumors and may enable identification of novel therapeutic targets
Access to and experience of later abortion: accounts from women in Scotland
Context:
Except in the presence of significant medical indications, the legal limit for abortion in Great Britain is 24 weeks’ gestation. Nevertheless, abortion for nonmedical reasons is not usually provided in Scotland after 18–20 weeks, meaning women have to travel to England for the procedure.
Methods:
In-depth interviews were conducted with 23 women presenting for "later" abortions (i.e., at 16 or more weeks’ gestation) in Scotland. Participants were women who sought an abortion at a participating National Health Service clinic between January and July 2013. Interviews addressed reasons for and consequences of later presentation, as well as women's experiences of abortion. Thematic analysis attended to emerging issues and employed the conceptual tool of candidacy.
Results:
Delayed recognition of pregnancy, changed life circumstances and conflicting candidacies for motherhood and having an abortion were common reasons for women's presentation for later abortion. Women perceived that the resources required to travel to England for a later abortion were potential barriers to access, and felt that such travel was distressing and stigmatizing. Participants who continued their pregnancy did so after learning they were at a later gestational age than expected or after receiving assurances of support from partners, friends or family.
Conclusions:
Reasons for seeking later abortion are complex and varied among women in Scotland, and suggest that reducing barriers to access and improving local provision of such abortions are a necessity. The candidacy framework allows for a fuller understanding of the difficulties involved in obtaining abortions
Isolated Left Main Coronary Artery Stenosis after Thoracic Radiation Therapy: To Operate or Not to Operate
Radiation therapy of neoplasms involving the chest or mediastinum results in a wide spectrum of cardiac complications including coronary artery disease, which can present in patients with few or no traditional cardiac risk factors. We report a case of radiation induced coronary artery disease in a 60-year-old female with a history of stage IIIA nonsmall cell lung carcinoma which was diagnosed eight years earlier and treated with chemotherapy and radiotherapy. She presented to the hospital with atypical chest pain that had occurred intermittently over the preceding week. Her initial electrocardiogram and cardiac enzymes were within normal limits. However, following an indeterminate exercise nuclear stress test, she developed chest pain and elevated cardiac enzymes. Coronary angiography demonstrated 90% stenosis of the left main coronary artery ostium, without any evidence of atherosclerotic disease or stenosis in other coronary arteries. She underwent surgical revascularization, which revealed dense adhesions surrounding the heart. During surgery, she developed severe bleeding and died. Coronary artery disease can present within years of radiation exposure, and ostial lesions are typical. Treatment is often challenging because of the effects of radiation on other tissues and the risks of revascularization procedures. Therefore, a multidisciplinary team approach should be considered
Reduction of Legionella spp. in water and in soil by a citrus plant extract vapor
Legionnaires disease is a severe form of pneumonia caused by Legionella spp. often isolated from environmental sources including soil and water. Legionella spp. are capable of replicating intracellularly within free living protozoa, once this has occurred Legionella spp. is particularly resistant to disinfectants. Citrus Essential Oils (EOs) vapours are effective antimicrobials against a range of microorganisms, with reductions of 5 log cells ml(-1) on a variety of surfaces. The aim of this investigation was to assess the efficacy of a citrus EO vapour against Legionella spp. in water and in soil systems. Reductions of viable cells of Legionella pneumophila, Legionella longbeachae, Legionella bozemanii and intra-amoebal culture of Legionella pneumophila (water system only), were assessed in soil and in water after exposure to a citrus EO vapour at concentrations ranging from 3.75 mg/l air to 15g/l air. Antimicrobial efficacy via different delivery systems (passive and active sintering of the vapour) was conducted in water and GC-MS analysis of the antimicrobial components (linalool, citral and β-pinene) determined. There was up to a 5 log cells ml(-1) reduction in Legionella spp. in soil after exposure to the citrus EOs vapour (15 mg/l air). The most susceptible strain in water was L. pneumophila with a 4 log cells ml(-1) reduction after 24 hrs via sintering (15 g/l air). Sintering the vapour through water increased the presence of the antimicrobial components, with a 61% increase of linalool. Therefore, the appropriate method of delivery of an antimicrobial citrus EO vapour may go some way in controlling Legionella spp. from environmental sources
High contrast imaging at the LBT: the LEECH exoplanet imaging survey
In Spring 2013, the LEECH (LBTI Exozodi Exoplanet Common Hunt) survey began
its 130-night campaign from the Large Binocular Telescope (LBT) atop Mt
Graham, Arizona. This survey benefits from the many technological achievements
of the LBT, including two 8.4-meter mirrors on a single fixed mount, dual
adaptive secondary mirrors for high Strehl performance, and a cold beam
combiner to dramatically reduce the telescope's overall background emissivity.
LEECH neatly complements other high-contrast planet imaging efforts by
observing stars at L' (3.8 m), as opposed to the shorter wavelength
near-infrared bands (1-2.4 m) of other surveys. This portion of the
spectrum offers deep mass sensitivity, especially around nearby adolescent
(0.1-1 Gyr) stars. LEECH's contrast is competitive with other extreme
adaptive optics systems, while providing an alternative survey strategy.
Additionally, LEECH is characterizing known exoplanetary systems with
observations from 3-5m in preparation for JWST.Comment: 12 pages, 5 figures. Proceedings of the SPIE, 9148-2
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