582 research outputs found
STABILITY AND CHANGE IN THE SELF-ESTEEM OF KINDERGARTEN THROUGH NINTH GRADERS: A ONE YEAR DEVELOPMENTAL STUDY
This study was designed to investigate the following questions: 1) Does self-esteem change over a one year period (as measured by the Piers-Harris Children\u27s Self-concept Scale)? 2) What is the extent and direction of individual score changes? and 3) Are there grade and/or gender differences in change patterns? Subjects (N=328) were students, K-9, in the Baxter Springs, Kansas, school district. Descriptive statistics, t-tests and one-way ANOVA were preliminary analyses. To answer question #1, a two-way ANOVA was used with gender and grade as independent variables and a difference score between the two times of testing as the dependent variable with Least Significant Differences contrast post hoc analyses done when appropriate. To look at individual differences, (question #2) differences in scores between the two times of testing were computed for each individual. Increases or decreases of more than the standard error of measurement of the Piers-Harris instrument were considered real changes. Increases, decreases and no change were computed for males and females in each class, K-9. This was done for Total Score and the six cluster scores of the Piers-Harris - Behavior, Intellectual and School Status, Physical Appearance and Attributes, Anxiety, Popularity, and Happiness and Satisfaction. Findings revealed that over a one year period, there is change in self-esteem, generally in an upward trend. There were more changes in Total Score and Physical Appearance and Attributes than the other cluster scores. Kindergarteners of both genders had the most change with fifth grade females and fourth grade males following. Possible reasons for change and the patterns of change are discussed
Structure and Stability of Si(114)-(2x1)
We describe a recently discovered stable planar surface of silicon, Si(114).
This high-index surface, oriented 19.5 degrees away from (001) toward (111),
undergoes a 2x1 reconstruction. We propose a complete model for the
reconstructed surface based on scanning tunneling microscopy images and
first-principles total-energy calculations. The structure and stability of
Si(114)-(2x1) arises from a balance between surface dangling bond reduction and
surface stress relief, and provides a key to understanding the morphology of a
family of surfaces oriented between (001) and (114).Comment: REVTeX, 4 pages + 3 figures. A preprint with high-resolution figures
is available at http://cst-www.nrl.navy.mil/papers/si114.ps . To be published
in Phys. Rev. Let
At-home blood collection and stabilization in high temperature climates using home RNA
Expanding whole blood sample collection for transcriptome analysis beyond traditional phlebotomy clinics will open new frontiers for remote immune research and telemedicine. Determining the stability of RNA in blood samples exposed to high ambient temperatures (\u3e30°C) is necessary for deploying home-sampling in settings with elevated temperatures (e.g., studying physiological response to natural disasters that occur in warm locations or in the summer). Recently, we have develope
Fabrication of Microstripline Wiring for Large Format Transition Edge Sensor Arrays
We have developed a process to integrate microstripline wiring with transition edge sensors (TES). The process includes additional layers for metal-etch stop and dielectric adhesion to enable recovery of parameters achieved in non-microstrip pixel designs. We report on device parameters in close-packed TES arrays achieved with the microstrip process including R(sub n), G, and T(sub c) uniformity. Further, we investigate limits of this method of producing high-density, microstrip wiring including critical current to determine the ultimate scalability of TES arrays with two layers of wiring
On the Correlations between Galaxy Properties and Supermassive Black Hole Mass
We use a large sample of upper limits and accurate estimates of supermassive
black holes masses coupled with libraries of host galaxy velocity dispersions,
rotational velocities and photometric parameters extracted from Sloan Digital
Sky Survey i-band images to establish correlations between the SMBH and host
galaxy parameters. We test whether the mass of the black hole, MBH, is
fundamentally driven by either local or global galaxy properties. We explore
correlations between MBH and stellar velocity dispersion sigma, bulge
luminosity, bulge mass Sersic index, bulge mean effective surface brightness,
luminosity of the galaxy, galaxy stellar mass, maximum circular velocity Vc,
galaxy dynamical and effective masses. We verify the tightness of the MBH-sigma
relation and find that correlations with other galaxy parameters do not yield
tighter trends. We do not find differences in the MBH-sigma relation of barred
and unbarred galaxies. The MBH-sigma relation of pseudo-bulges is also coarser
and has a different slope than that involving classical bulges. The MBH-bulge
mass is not as tight as the MBH-sigma relation, despite the bulge mass proving
to be a better proxy of MBH than bulge luminosity. We find a rather poor
correlation between MBH and Sersic index suggesting that MBH is not related to
the bulge light concentration. The correlations between MBH and galaxy
luminosity or mass are not a marked improvement over the MBH sigma relation. If
Vc is a proxy for the dark matter halo mass, the large scatter of the MBH-Vc
relation then suggests that MBH is more coupled to the baryonic rather than the
dark matter. We have tested the need for a third parameter in the MBH scaling
relations, through various linear correlations with bulge and galaxy
parameters, only to confirm that the fundamental plane of the SMBH is mainly
driven by sigma, with a small tilt due to the effective radius. (Abridged)Comment: 32 pages, 18 figures, 6 tables, accepted for publication in MNRA
Global Warming Will Bring New Fungal Diseases for Mammals
Fungi are major pathogens of plants, other fungi, rotifers, insects, and amphibians, but relatively few cause disease in mammals. Fungi became important human pathogens only in the late 20th century, primarily in hosts with impaired immunity as a consequence of medical interventions or HIV infection. The relatively high resistance of mammals has been attributed to a combination of a complex immune system and endothermy. Mammals maintain high body temperatures relative to environmental temperatures, creating a thermally restrictive ambient for the majority of fungi. According to this view, protection given by endothermy requires a temperature gradient between those of mammals and the environment. We hypothesize that global warming will increase the prevalence of fungal diseases in mammals by two mechanisms: (i) increasing the geographic range of currently pathogenic species and (ii) selecting for adaptive thermotolerance for species with significant pathogenic potential but currently not pathogenic by virtue of being restricted by mammalian temperatures
Superconductivity in Fullerides
Experimental studies of superconductivity properties of fullerides are
briefly reviewed. Theoretical calculations of the electron-phonon coupling, in
particular for the intramolecular phonons, are discussed extensively. The
calculations are compared with coupling constants deduced from a number of
different experimental techniques. It is discussed why the A_3 C_60 are not
Mott-Hubbard insulators, in spite of the large Coulomb interaction. Estimates
of the Coulomb pseudopotential , describing the effect of the Coulomb
repulsion on the superconductivity, as well as possible electronic mechanisms
for the superconductivity are reviewed. The calculation of various properties
within the Migdal-Eliashberg theory and attempts to go beyond this theory are
described.Comment: 33 pages, latex2e, revtex using rmp style, 15 figures, submitted to
Review of Modern Physics, more information at
http://radix2.mpi-stuttgart.mpg.de/fullerene/fullerene.htm
Local Supermassive Black Holes, Relics of Active Galactic Nuclei and the X-ray Background
We quantify the importance of mass accretion during AGN phases in the growth
of supermassive black holes (BH) by comparing the mass function of black holes
in the local universe with that expected from AGN relics, which are black holes
grown entirely with mass accretion during AGN phases. The local BH mass
function (BHMF) is estimated by applying the well-known correlations between BH
mass, bulge luminosity and stellar velocity dispersion to galaxy luminosity and
velocity functions. The density of BH's in the local universe is 4.6 (-1.4;
+1.9) (h/0.7)^2 10^5 Msun Mpc^-3. The relic BHMF is derived from the continuity
equation with the only assumption that AGN activity is due to accretion onto
massive BH's and that merging is not important. We find that the relic BHMF at
z=0 is generated mainly at z<3. Moreover, the BH growth is anti-hierarchical in
the sense that smaller BH's (MBH< 10^7 Msun) grow at lower redshifts (z<1) with
respect to more massive one's (z~1-3). Unlike previous work, we find that the
BHMF of AGN relics is perfectly consistent with the local BHMF indicating the
local BH's were mainly grown during AGN activity. This agreement is obtained
while satisfying, at the same time, the constraints imposed from the X-ray
background. The comparison with the local BHMF also suggests that the merging
process is not important in shaping the relic BHMF, at least at low redshifts
(z<3). Our analysis thus suggests the following scenario: local black holes
grew during AGN phases in which accreting matter was converted into radiation
with efficiencies epsilon = 0.04-0.16 and emitted at a fraction lambda =
0.1-1.7 of the Eddington luminosity. The average total lifetime of these active
phases ranges from ~4.5 10^8 yr for MBH
10^9 Msun. (abridged)Comment: 19 pages, 18 figures, MNRAS in press, minor changes following
referee's comment
Coordinated optimization of visual cortical maps (I) Symmetry-based analysis
In the primary visual cortex of primates and carnivores, functional
architecture can be characterized by maps of various stimulus features such as
orientation preference (OP), ocular dominance (OD), and spatial frequency. It
is a long-standing question in theoretical neuroscience whether the observed
maps should be interpreted as optima of a specific energy functional that
summarizes the design principles of cortical functional architecture. A
rigorous evaluation of this optimization hypothesis is particularly demanded by
recent evidence that the functional architecture of OP columns precisely
follows species invariant quantitative laws. Because it would be desirable to
infer the form of such an optimization principle from the biological data, the
optimization approach to explain cortical functional architecture raises the
following questions: i) What are the genuine ground states of candidate energy
functionals and how can they be calculated with precision and rigor? ii) How do
differences in candidate optimization principles impact on the predicted map
structure and conversely what can be learned about an hypothetical underlying
optimization principle from observations on map structure? iii) Is there a way
to analyze the coordinated organization of cortical maps predicted by
optimization principles in general? To answer these questions we developed a
general dynamical systems approach to the combined optimization of visual
cortical maps of OP and another scalar feature such as OD or spatial frequency
preference.Comment: 90 pages, 16 figure
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