110 research outputs found
Analisis Kestabilan Model SEIR Penyebaran Penyakit Campak dengan Pengaruh Imunisasi dan Vaksin MR
Measles is a contagious infectious disease caused by a virus and has the potential to cause an outbreak. Immunization and vaccination are carried out as an effort to prevent the spread of measles. This study aims to analyze and determine the stability of the SEIR model on the spread of measles with the influence of immunization and MR vaccines. The results obtained from model analysis, namely there are two disease free and endemic equilibrium points. If the conditions are met, the measles-free equilibrium point will be asymptotically stable and the measles endemic equilibrium point will be stable. Numerical solutions show a decrease in the rate of spread of measles due to the effect of immunization and the addition of MR vaccines
The material properties of a bacterial-derived biomolecular condensate tune biological function in natural and synthetic systems
Intracellular phase separation is emerging as a universal principle for organizing biochemical reactions in time and space. It remains incompletely resolved how biological function is encoded in these assemblies and whether this depends on their material state. The conserved intrinsically disordered protein PopZ forms condensates at the poles of the bacterium Caulobacter crescentus, which in turn orchestrate cell-cycle regulating signaling cascades. Here we show that the material properties of these condensates are determined by a balance between attractive and repulsive forces mediated by a helical oligomerization domain and an expanded disordered region, respectively. A series of PopZ mutants disrupting this balance results in condensates that span the material properties spectrum, from liquid to solid. A narrow range of condensate material properties supports proper cell division, linking emergent properties to organismal fitness. We use these insights to repurpose PopZ as a modular platform for generating tunable synthetic condensates in human cells
Photometry of Variable Stars from Dome A, Antarctica
Dome A on the Antarctic plateau is likely one of the best observing sites on
Earth thanks to the excellent atmospheric conditions present at the site during
the long polar winter night. We present high-cadence time-series aperture
photometry of 10,000 stars with i<14.5 mag located in a 23 square-degree region
centered on the south celestial pole. The photometry was obtained with one of
the CSTAR telescopes during 128 days of the 2008 Antarctic winter.
We used this photometric data set to derive site statistics for Dome A and to
search for variable stars. Thanks to the nearly-uninterrupted synoptic
coverage, we find 6 times as many variables as previous surveys with similar
magnitude limits. We detected 157 variable stars, of which 55% are
unclassified, 27% are likely binaries and 17% are likely pulsating stars. The
latter category includes delta Scuti, gamma Doradus and RR Lyrae variables. One
variable may be a transiting exoplanet.Comment: Accepted for publication in the Astronomical Journal. PDF version
with high-resolution figures available at
http://faculty.physics.tamu.edu/lmacri/papers/wang11.pd
Putting the Pieces Together: Integrative Modeling Platform Software for Structure Determination of Macromolecular Assemblies
A set of software tools for building and distributing models of macromolecular assemblies uses an integrative structure modeling approach, which casts the building of models as a computational optimization problem where information is encoded into a scoring function used to evaluate candidate models
Effective practices of international volunteering for health : perspectives from partner organizations
Abstract: The demand for international volunteer experiences to promote global health and nutrition is increasing and numerous studies have documented the experiences of the international volunteers who travel abroad; however, little is known about effective practices from the perspective of partner organizations. This study aims to understand how variables such as the skill-level of volunteers, the duration of service, cultural and language training, and other key variables affect partner organizations’ perceptions of volunteer effectiveness at promoting healthcare and nutrition..
Egg mortality: predation and hydrography in the central Baltic
Cod and sprat are the dominant fish species in the Baltic pelagic ecosystem, both of great economic importance and ecologically strongly interlinked. Management of both species is challenged by highly variable recruitment success. Recent studies have identified predation and hydrographic conditions during the egg phase to be of critical importance. Two years of extensive field investigations in the Bornholm Basin, central Baltic Sea, were undertaken. In 2002, a typical stagnation situation characterized by low salinity and poor oxygen conditions was investigated, and in early 2003, a major inflow of North Sea water completely changed the hydrographic conditions by increasing salinity and oxygen content, thereby altering ecological conditions. The goal was to quantify egg mortality caused by predation and hydrography, and to compare these estimates with independent estimates based on cohort analysis. Results indicated high intra-annual variability in egg mortality. Cod and sprat egg mortality responded differently to the major Baltic inflow:
mortality related to hydrographic conditions increased for sprat and decreased for cod. On the other hand, predation mortality during peak spawning decreased for sprat and increased for cod
SDSS-III: Massive Spectroscopic Surveys of the Distant Universe, the Milky Way Galaxy, and Extra-Solar Planetary Systems
Building on the legacy of the Sloan Digital Sky Survey (SDSS-I and II),
SDSS-III is a program of four spectroscopic surveys on three scientific themes:
dark energy and cosmological parameters, the history and structure of the Milky
Way, and the population of giant planets around other stars. In keeping with
SDSS tradition, SDSS-III will provide regular public releases of all its data,
beginning with SDSS DR8 (which occurred in Jan 2011). This paper presents an
overview of the four SDSS-III surveys. BOSS will measure redshifts of 1.5
million massive galaxies and Lya forest spectra of 150,000 quasars, using the
BAO feature of large scale structure to obtain percent-level determinations of
the distance scale and Hubble expansion rate at z<0.7 and at z~2.5. SEGUE-2,
which is now completed, measured medium-resolution (R=1800) optical spectra of
118,000 stars in a variety of target categories, probing chemical evolution,
stellar kinematics and substructure, and the mass profile of the dark matter
halo from the solar neighborhood to distances of 100 kpc. APOGEE will obtain
high-resolution (R~30,000), high signal-to-noise (S/N>100 per resolution
element), H-band (1.51-1.70 micron) spectra of 10^5 evolved, late-type stars,
measuring separate abundances for ~15 elements per star and creating the first
high-precision spectroscopic survey of all Galactic stellar populations (bulge,
bar, disks, halo) with a uniform set of stellar tracers and spectral
diagnostics. MARVELS will monitor radial velocities of more than 8000 FGK stars
with the sensitivity and cadence (10-40 m/s, ~24 visits per star) needed to
detect giant planets with periods up to two years, providing an unprecedented
data set for understanding the formation and dynamical evolution of giant
planet systems. (Abridged)Comment: Revised to version published in The Astronomical Journa
CANDELS: The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey - The Hubble Space Telescope Observations, Imaging Data Products and Mosaics
This paper describes the Hubble Space Telescope imaging data products and
data reduction procedures for the Cosmic Assembly Near-IR Deep Extragalactic
Legacy Survey (CANDELS). This survey is designed to document the evolution of
galaxies and black holes at , and to study Type Ia SNe beyond
. Five premier multi-wavelength sky regions are selected, each with
extensive multiwavelength observations. The primary CANDELS data consist of
imaging obtained in the Wide Field Camera 3 / infrared channel (WFC3/IR) and
UVIS channel, along with the Advanced Camera for Surveys (ACS). The
CANDELS/Deep survey covers \sim125 square arcminutes within GOODS-N and
GOODS-S, while the remainder consists of the CANDELS/Wide survey, achieving a
total of \sim800 square arcminutes across GOODS and three additional fields
(EGS, COSMOS, and UDS). We summarize the observational aspects of the survey as
motivated by the scientific goals and present a detailed description of the
data reduction procedures and products from the survey. Our data reduction
methods utilize the most up to date calibration files and image combination
procedures. We have paid special attention to correcting a range of
instrumental effects, including CTE degradation for ACS, removal of electronic
bias-striping present in ACS data after SM4, and persistence effects and other
artifacts in WFC3/IR. For each field, we release mosaics for individual epochs
and eventual mosaics containing data from all epochs combined, to facilitate
photometric variability studies and the deepest possible photometry. A more
detailed overview of the science goals and observational design of the survey
are presented in a companion paper.Comment: 39 pages, 25 figure
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