859 research outputs found
College Readiness Indicators of First-Generation Hispanic High School Students in South Texas
The purpose of this study was to determine if a relationship exists between first generation Hispanic student participation in an AVID program and college readiness. The dependent variable, college readiness, was measured by passing the Texas Success Initiative (TSI) Reading, Writing, and Math assessment. Predictor variables included Advancement Via Individual Determination (AVID) elective course participation, Advanced Placement courses taken, Advanced Placement Exams taken, Advanced Placement Exams passed, Dual Enrollment Courses Passed, and ACT Composite score. A factor analysis was performed on the predictor variables, resulting in three independent variables for the study: AVID elective course participation, Average of T-scores for Dual Enrollment and ACT, and Average of T-scores for AP.
This is a quantitative study that utilized pre-existing data from four high schools in a large South Texas school district. A logistic regression analysis was used to examine if AVID elective course participation, Advanced Placement courses taken, Advanced Placement Exams taken, Advanced Placement Exams passed, Dual Enrollment Courses Passed, and ACT Composite scores were a function of TSI scores in Reading, Writing, and Math. The null hypothesis for the present study were tested at the .05 level of significance.
The review of literature on college readiness provided the theoretic framework for this study. The theoretic framework was based on David Conley’s (2007) Theory of College Readiness.
The findings from this study indicated the following: 1) AVID elective course participation in high school is a function of TSI scores in Reading, Writing, and Math, 2) Average of T-scores for Dual Enrollment Courses and ACT scores were a function of TSI scores in Reading, Writing, and Math, 3) Average of T-scores for AP were not a function of TSI scores in Reading, Writing, and Math, 4) AVID elective course participation in middle school was not a function of TSI scores in Reading, Writing, and Math
A Physiological Role for Amyloid Beta Protein: Enhancement of Learning and Memory
Amyloid beta protein (A[beta]) is well recognized as having a significant role in the pathogenesis of Alzheimer's disease (AD). The reason for the presence of A[beta] and its physiological role in non-disease states is not clear. In these studies, low doses of A[beta] enhanced memory retention in two memory tasks and enhanced acetylcholine production in the hippocampus _in vivo_. We then tested whether endogenous A[beta] has a role in learning and memory in young, cognitively intact mice by blocking endogenous A[beta] in healthy 2-month-old CD-1 mice. Blocking A[beta] with antibody to A[beta] or DFFVG (which blocks A[beta] binding) or decreasing A[beta] expression with an antisense directed at the A[beta] precursor APP all resulted in impaired learning in T-maze foot-shock avoidance. Finally, A[beta]1-42 facilitated induction and maintenance of long term potentiation in hippocampal slices, whereas antibodies to A[beta] inhibited hippocampal LTP. These results indicate that in normal healthy young animals the presence of A[beta] is important for learning and memory
The Histone 3'-Terminal Stem-Loop-Binding Protein Enhances Translation through a Functional and Physical Interaction with Eukaryotic Initiation Factor 4G (eIF4G) and eIF3
Metazoan cell cycle-regulated histone mRNAs are unique cellular mRNAs in that they terminate in a highly conserved stem-loop structure instead of a poly(A) tail. Not only is the stem-loop structure necessary for 3'-end formation but it regulates the stability and translational efficiency of histone mRNAs. The histone stem-loop structure is recognized by the stem-loop-binding protein (SLBP), which is required for the regulation of mRNA processing and turnover. In this study, we show that SLBP is required for the translation of mRNAs containing the histone stem-loop structure. Moreover, we show that the translation of mRNAs ending in the histone stem-loop is stimulated in Saccharomyces cerevisiae cells expressing mammalian SLBP. The translational function of SLBP genetically required eukaryotic initiation factor 4E (eIF4E), eIF4G, and eIF3, and expressed SLBP coisolated with S. cerevisiae initiation factor complexes that bound the 5' cap in a manner dependent on eIF4G and eIF3. Furthermore, eIF4G coimmunoprecipitated with endogenous SLBP in mammalian cell extracts and recombinant SLBP and eIF4G coisolated. These data indicate that SLBP stimulates the translation of histone mRNAs through a functional interaction with both the mRNA stem-loop and the 5' cap that is mediated by eIF4G and eIF3
Regularly log-periodic functions and some applications
We prove a Tauberian theorem for the Laplace--Stieltjes transform and
Karamata-type theorems in the framework of regularly log-periodic functions. As
an application we determine the exact tail behavior of fixed points of certain
type smoothing transforms
EFFECT OF LONGITUDE-DEPENDENT CLOUD COVERAGE ON EXOPLANET VISIBLE WAVELENGTH REFLECTED-LIGHT PHASE CURVES
We use a planetary albedo model to investigate variations in visible wavelength phase curves of exoplanets. Thermal and cloud properties for these exoplanets are derived using one-dimensional radiative-convective and cloud simulations. The presence of clouds on these exoplanets significantly alters their planetary albedo spectra. We confirm that non-uniform cloud coverage on the dayside of tidally locked exoplanets will manifest as changes to the magnitude and shift of the phase curve. In this work, we first investigate a test case of our model using a Jupiter-like planet, at temperatures consistent to 2.0 AU insolation from a solar type star, to consider the effect of H[subscript 2]O clouds. We then extend our application of the model to the exoplanet Kepler-7b and consider the effect of varying cloud species, sedimentation efficiency, particle size, and cloud altitude. We show that, depending on the observational filter, the largest possible shift of the phase curve maximum will be ~2°–10° for a Jupiter-like planet, and up to ~30° (~0.08 in fractional orbital phase) for hot-Jupiter exoplanets at visible wavelengths as a function of dayside cloud distribution with a uniformly averaged thermal profile. The models presented in this work can be adapted for a variety of planetary cases at visible wavelengths to include variations in planet–star separation, gravity, metallicity, and source-observer geometry. Finally, we tailor our model for comparison with, and confirmation of, the recent optical phase-curve observations of Kepler-7b with the Kepler space telescope. The average planetary albedo can vary between 0.1 and 0.6 for the 1300 cloud scenarios that were compared to the observations. Many of these cases cannot produce a high enough albedo to match the observations. We observe that smaller particle size and increasing cloud altitude have a strong effect on increasing albedo. In particular, we show that a set of models where Kepler-7b has roughly half of its dayside covered in small-particle clouds high in the atmosphere, made of bright minerals like MgSiO[subscript 3] and Mg[subscript 2]SiO[subscript 4], provide the best fits to the observed offset and magnitude of the phase-curve, whereas Fe clouds are found to be too dark to fit the observations
Pendulum Mode Thermal Noise in Advanced Interferometers: A comparison of Fused Silica Fibers and Ribbons in the Presence of Surface Loss
The use of fused-silica ribbons as suspensions in gravitational wave
interferometers can result in significant improvements in pendulum mode thermal
noise. Surface loss sets a lower bound to the level of noise achievable, at
what level depends on the dissipation depth and other physical parameters. For
LIGO II, the high breaking strength of pristine fused silica filaments, the
correct choice of ribbon aspect ratio (to minimize thermoelastic damping), and
low dissipation depth combined with the other achievable parameters can reduce
the pendulum mode thermal noise in a ribbon suspension well below the radiation
pressure noise. Despite producing higher levels of pendulum mode thermal noise,
cylindrical fiber suspensions provide an acceptable alternative for LIGO II,
should unforeseen problems with ribbon suspensions arise.Comment: Submitted to Physics Letters A (Dec. 14, 1999). Resubmitted to
Physics Letters A (Apr. 3, 2000) after internal (LSC) review process. PACS -
04.80.Nn, 95.55.Ym, 05.40.C
The z-spectrum from human blood at 7T
Chemical Exchange Saturation Transfer (CEST) has been used to assess healthy and pathological tissue in both animals and humans. However, the CEST signal from blood has not been fully assessed. This paper presents the CEST and nuclear Overhauser enhancement (NOE) signals detected in human blood measured via z-spectrum analysis. We assessed the effects of blood oxygenation levels, haematocrit, cell structure and pH upon the z-spectrum in ex vivo human blood for different saturation powers at 7T. The data were analysed using Lorentzian difference (LD) model fitting and AREX (to compensate for changes in T1), which have been successfully used to study CEST effects in vivo. Full Bloch-McConnell fitting was also performed to provide an initial estimate of exchange rates and transverse relaxation rates of the various pools. CEST and NOE signals were observed at 3.5 ppm, -1.7ppm and -3.5 ppm and were found to originate primarily from the red blood cells (RBCs), although the amide proton transfer (APT) CEST effect, and NOEs showed no dependence upon oxygenation levels. Upon lysing, the APT and NOE signals fell significantly. Different pH levels in blood resulted in changes in both the APT and NOE (at -3.5ppm), which suggests that this NOE signal is in part an exchange relayed process. These results will be important for assessing in vivo z-spectra
Autopsy findings in patients with uterine sarcoma
Autopsy findings were reviewed in 22 patients treated for uterine sarcoma at the University of Michigan Hospitals. Included are 11 mixed mesodermal tumors, 6 endometrial stromal sarcomas, and 5 leiomyosarcomas. Only one patient died with disease limited to the pelvis. Forty-five percent of the patients died with disease limited to the pelvis and abdomen. The most common site of disease above the diaphragm was the lung. Lymph nodes were involved in 59% of our patients. There were no obvious differences in the patterns of spread between the tumor types.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24678/1/0000097.pd
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