763 research outputs found
The Effect of Educational Games on the Level of Motivation in Science of Grade IV Students in Angel Villarica Central School
The concern of this study is to determine The Effect of Educational Games on the Level of Motivation of Grade 4 Students in Angel Villarica Central Elementary School. A quantitative research design employing an experimental method was used in the study. The essential data were gathered from a total number of seventy-three (73) respondents, 36 students from the control group and 37 students from the experimental group, with the aid of a questionnaire validated by a panel of experts. The statistical tools used in this study were Average Weighted Mean and t-test for Independent Sample Means. The study proved that there was no significant difference between the mean gain scores of the experimental and control groups. It means that the use of educational games has no significant effect on the level of motivation in science. However, educational games can be considered as an alternative method in delivering the Science lesson. It was being recommended in the study to conduct a similar study in the future to confirm that educational games have no effect on the level of motivation and involve a wider scope in the conduct of the stud
AGN Populations in Large Volume X-ray Surveys: Photometric Redshifts and Population Types found in the Stripe 82X Survey
Multi-wavelength surveys covering large sky volumes are necessary to obtain
an accurate census of rare objects such as high luminosity and/or high redshift
active galactic nuclei (AGN). Stripe 82X is a 31.3 deg X-ray survey with
and -Newton observations overlapping the legacy Sloan Digital
Sky Survey (SDSS) Stripe 82 field, which has a rich investment of
multi-wavelength coverage from the ultraviolet to the radio. The wide-area
nature of this survey presents new challenges for photometric redshifts for AGN
compared to previous work on narrow-deep fields because it probes different
populations of objects that need to be identified and represented in the
library of templates. Here we present an updated X-ray plus multi-wavelength
matched catalog, including counterparts, and estimated photometric
redshifts for 5961 (96% of a total of 6181) X-ray sources, which have a
normalized median absolute deviation, = 0.06 and an outlier
fraction, = 13.7%. The populations found in this survey, and the
template libraries used for photometric redshifts, provide important guiding
principles for upcoming large-area surveys such as and 3 (in
X-ray) and the Large Synoptic Survey Telescope (LSST; optical).Comment: Accepted for publication by The Astrophysical Journal (33 pages, 20
figures, 13 tables). Final catalog of counterparts and photo-z supplementing
the paper available here:
http://stripe82x.com/docs/stripe82x-photometric-redshifts-and-multiwavelength-data-catalog
The Investigation and Management of Iliac Artery Endofibrosis:Lessons Learned from a Case Series
BAAD: a Biomass And Allometry Database for woody plants
Understanding how plants are constructedâi.e., how key size dimensions and the amount of mass invested in different tissues varies among individualsâis essential for modeling plant growth, carbon stocks, and energy fluxes in the terrestrial biosphere. Allocation patterns can differ through ontogeny, but also among coexisting species and among species adapted to different environments. While a variety of models dealing with biomass allocation exist, we lack a synthetic understanding of the underlying processes. This is partly due to the lack of suitable data sets for validating and parameterizing models. To that end, we present the Biomass And Allometry Database (BAAD) for woody plants. The BAAD contains 259â634 measurements collected in 176 different studies, from 21â084 individuals across 678 species. Most of these data come from existing publications. However, raw data were rarely made public at the time of publication. Thus, the BAAD contains data from different studies, transformed into standard units and variable names. The transformations were achieved using a common workflow for all raw data files. Other features that distinguish the BAAD are: (i) measurements were for individual plants rather than stand averages; (ii) individuals spanning a range of sizes were measured; (iii) plants from 0.01â100 m in height were included; and (iv) biomass was estimated directly, i.e., not indirectly via allometric equations (except in very large trees where biomass was estimated from detailed subâsampling). We included both wild and artificially grown plants. The data set contains the following size metrics: total leaf area; area of stem crossâsection including sapwood, heartwood, and bark; height of plant and crown base, crown area, and surface area; and the dry mass of leaf, stem, branches, sapwood, heartwood, bark, coarse roots, and fine root tissues. We also report other properties of individuals (age, leaf size, leaf mass per area, wood density, nitrogen content of leaves and wood), as well as information about the growing environment (location, light, experimental treatment, vegetation type) where available. It is our hope that making these data available will improve our ability to understand plant growth, ecosystem dynamics, and carbon cycling in the world\u27s vegetation
Narrow-band imaging versus white light for the detection of proximal colon serrated lesions: a randomized, controlled trial
Background
The value of narrow-band imaging (NBI) for detecting serrated lesions is unknown.
Objective
To assess NBI for the detection of proximal colon serrated lesions.
Design
Randomized, controlled trial.
Setting
Two academic hospital outpatient units.
Patients
Eight hundred outpatients 50 years of age and older with intact colons undergoing routine screening, surveillance, or diagnostic examinations.
Interventions
Randomization to colon inspection in NBI versus white-light colonoscopy.
Main Outcome Measurements
The number of serrated lesions (sessile serrated polyps plus hyperplastic polyps) proximal to the sigmoid colon.
Results
The mean inspection times for the whole colon and proximal colon were the same for the NBI and white-light groups. There were 204 proximal colon lesions in the NBI group and 158 in the white light group (P = .085). Detection of conventional adenomas was comparable in the 2 groups.
Limitations
Lack of blinding, endoscopic estimation of polyp location.
Conclusion
NBI may increase the detection of proximal colon serrated lesions, but the result in this trial did not reach significance. Additional study of this issue is warranted. (Clinical trial registration number: NCT01572428.
Spitzer mid-infrared spectroscopy of compact symmetric objects: What powers radio-loud active galactic nuclei?
We present low- and high-resolution mid-infrared (mid-IR) spectra and
photometry for eight compact symmetric objects (CSOs) taken with the Infrared
Spectrograph on the Spitzer Space Telescope. The hosts of these young, powerful
radio galaxies show significant diversity in their mid-IR spectra. This
includes multiple atomic fine-structure lines, H2 gas, polycyclic aromatic
hydrocarbon (PAH) emission, warm dust from T = 50 to 150 K, and silicate
features in both emission and absorption. There is no evidence in the mid-IR of
a single template for CSO hosts, but 5/8 galaxies show similar moderate levels
of star formation (<10 M_sun/yr from PAH emission) and silicate dust in a
clumpy torus. The total amount of extinction ranges from A_V ~ 10 to 30, and
the high-ionization [Ne V] 14.3 and 24.3 um transitions are not detected for
any galaxy in the sample. Almost all CSOs show contributions both from star
formation and active galactic nuclei (AGNs), suggesting that they occupy a
continuum between pure starbursts and AGNs. This is consistent with the
hypothesis that radio galaxies are created following a galactic merger; the
timing of the radio activity onset means that contributions to the IR
luminosity from both merger-induced star formation and the central AGN are
likely. Bondi accretion is capable of powering the radio jets for almost all
CSOs in the sample; the lack of [Ne V] emission suggests an advection-dominated
accretion flow mode as a possible candidate. Merging black holes (BHs) with
M_BH > 10^8 M_sun likely exist in all of the CSOs in the sample; however, there
is no direct evidence from these data that BH spin energy is being tapped as an
alternative mode for powering the radio jets.Comment: 22 pages, 14 figures; published in Ap
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CD11a polymorphisms regulate TH2 cell homing and TH2-related disease
Background:
TH2-dependent diseases vary in severity according to genotype, but relevant gene polymorphisms remain largely unknown. The integrin CD11a is a critical determinant of allergic responses, and allelic variants of this gene might influence allergic phenotypes.
Objective:
We sought to determine major CD11a allelic variants in mice and human subjects and their importance to allergic disease expression.
Methods:
We sequenced mouse CD11a alleles from C57BL/6 and BALB/c strains to identify major polymorphisms; human CD11a single nucleotide polymorphisms were compared with allergic disease phenotypes as part of the international HapMap project. Mice on a BALB/c or C57BL/6 background and congenic for the other strain's CD11a allele were created to determine the importance of mouse CD11a polymorphisms in vivo and in vitro.
Results:
Compared with the C57BL/6 allele, the BALB/c CD11a allele contained a nonsynonymous change from asparagine to aspartic acid within the metal ion binding domain. In general, the BALB/c CD11a allele enhanced and the C57BL/6 CD11a allele suppressed TH2 cellâdependent disease caused by the parasite Leishmania major and allergic lung disease caused by the fungus Aspergillus niger. Relative to the C57BL/6 CD11a allele, the BALB/c CD11a allele conferred both greater T-cell adhesion to CD54 in vitro and enhanced TH2 cell homing to lungs in vivo. We further identified a human CD11a polymorphism that significantly associated with atopic disease and relevant allergic indices.
Conclusions:
Polymorphisms in CD11a critically influence TH2 cell homing and diverse TH2-dependent immunopathologic states in mice and potentially influence the expression of human allergic disease
The Evolution of the Star Formation Rate of Galaxies at 0.0 < z < 1.2
We present the 24 micron rest-frame luminosity function (LF) of star-forming
galaxies in the redshift range 0.0 < z < 0.6 constructed from 4047
spectroscopic redshifts from the AGN and Galaxy Evolution Survey of 24 micron
selected sources in the Bootes field of the NOAO Deep Wide-Field Survey. This
sample provides the best available combination of large area (9 deg^2), depth,
and statistically complete spectroscopic observations, allowing us to probe the
evolution of the 24 micron LF of galaxies at low and intermediate redshifts
while minimizing the effects of cosmic variance. In order to use the observed
24 micron luminosity as a tracer for star formation, active galactic nuclei
(AGNs) that could contribute significantly at 24 micron are identified and
excluded from our star-forming galaxy sample based on their mid-IR spectral
energy distributions or the detection of X-ray emission. The evolution of the
24 micron LF of star-forming galaxies for redshifts of z < 0.65 is consistent
with a pure luminosity evolution where the characteristic 24 micron luminosity
evolves as (1+z)^(3.8+/-0.3). We extend our evolutionary study to encompass 0.0
< z < 1.2 by combining our data with that of the Far-Infrared Deep
Extragalactic Legacy Survey. Over this entire redshift range the evolution of
the characteristic 24 micron luminosity is described by a slightly shallower
power law of (1+z)^(3.4+/-0.2). We find a local star formation rate density of
(1.09+/-0.21) x 10^-2 Msun/yr/Mpc^-3, and that it evolves as (1+z)^(3.5+/-0.2)
over 0.0 < z < 1.2. These estimates are in good agreement with the rates using
optical and UV fluxes corrected for the effects of intrinsic extinction in the
observed sources. This agreement confirms that star formation at z <~ 1.2 is
robustly traced by 24 micron observations and that it largely occurs in
obscured regions of galaxies. (Abridged)Comment: ApJ, in press, 16 pages 9 figure
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Active Galactic Nucleus and Starburst Classification from Spitzer MidâInfrared Spectra for HighâRedshift SWIRE Sources
Spectra have been obtained with the Infrared Spectrograph (IRS) on the Spitzer Space Telescope for 20 sources in the Lockman Hole field of the SWIRE survey. The sample is divided between sources with indicators of an obscured AGN, based primarily on X-ray detections of optically faint sources, and sources with indicators of a starburst, based on optical and near-infrared spectral energy distributions (SEDs), which show a luminosity peak from stellar photospheric emission. Ten of the 11 AGN sources have IRS spectra that show silicate absorption or are power laws; only one AGN source shows PAH emission features. All nine of the sources showing starburst SEDs in the near-infrared show PAH emission features in the IRS spectra. Redshifts are determined from the IRS spectra for all nine starbursts (1.0 < z < 1.9) and 8 of the 11 AGNs (0.6 < z < 2.5). Classification as AGN because of an X-ray detection, the classification as AGN or starburst derived from the photometric SED, and the IRS spectroscopic classification as AGN (silicate absorption) or starburst (PAH emission) are all consistent in 18 of 20 sources. The surface density for starbursts that are most luminous in the mid-infrared is less than that for the most luminous AGNs within the redshift interval 1.7 lesssim z lesssim 1.9. This result implies that mid-infrared source counts at high redshift are dominated by AGNs for fΜ(24 Όm) gsim 1.0 mJy.Astronom
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