5,328 research outputs found
Evaluating extreme rainfall changes over Taiwan using a standardized index
The annual daily maximum precipitation (rx1day) is widely used to represent extreme events and is an important parameter in climate change studies. However, the climate variability in rx1day is sensitive to outliers and has difficulty representing the characteristics of large areas. We propose to use the probability index (PI), based on the cumulative density function (CDF) of a generalized extreme value (GEV) distribution to fit and standardize the rx1day to represent extreme event records in this study. A good correlation between the area-averaged PIs of the observed stations and those of the gridded dataset can be found over Taiwan. From the past PI records, there is no distinct trend in western Taiwan before the end of the 20th century, but a climate regime change happened during 2002 - 2003. The dual change effects from both the variance and linear trend of extreme events are identified over the northeastern and southern parts of Taiwan, along with the island's central and southern regions, showing different abrupt changing trends and intensity. The PI can also be calculated using climate projection data to represent the characteristics of future extreme changes. The climate variability of PIs on the present (ALL) and future (RCP4.5 and RCP8.5) scenarios were evaluated using the 16 Couple Model Intercomparison Projects Phase-5 models (CMIP5). The simulated present fluctuations in PIs are smaller than those of actual observations. In the 21st century, the RCP8.5 scenario shows that the PI significantly increases by 10% during the first half of the century, and 14% by the end of the century.1112Ysciescopu
The [O II] lambda 3727 Luminosity Function at z ~ 1
We measure the evolution of the [OII]lambda 3727 luminosity function at
0.75<z<1.45 using high-resolution spectroscopy of ~14,000 galaxies observed by
the DEEP2 galaxy redshift survey. We find that brighter than L_{OII}=10^{42}
erg s^(-1) the luminosity function is well-represented by a power law dN/dL ~
L^{\alpha} with slope \alpha ~ -3. The number density of [OII] emitting
galaxies above this luminosity declines by a factor of >~2.5 between z ~ 1.35
and z ~ 0.84. In the limit of no number-density evolution, the characteristic
[OII] luminosity, L^*_[OII], defined as the luminosity where the space density
equals 10^{-3.5} dex^{-1} Mpc^{-3}, declines by a factor of ~1.8 over the same
redshift interval. Assuming that L_[OII] is proportional to the star-formation
rate (SFR), and negligible change in the typical dust attenuation in galaxies
at fixed [OII] luminosity, the measured decline in L^*_[OII] implies a ~25% per
Gyr decrease in the amount of star formation in galaxies during this epoch.
Adopting a faint-end power-law slope of -1.3\pm0.2, we derive the comoving SFR
density in four redshift bins centered around z~1 by integrating the observed
[OII] luminosity function using a local, empirical calibration between L_[OII]
and SFR, which statistically accounts for variations in dust attenuation and
metallicity among galaxies. We find that our estimate of the SFR density at z~1
is consistent with previous measurements based on a variety of independent SFR
indicators.Comment: 10 pages, 6 figures, 2 tables, resubmitted to ApJ, in emulateapj
style. Comparison with narrow-band observations added. Wavelength coverage
included into complete function, little effects. The data is available on
http://bias.cosmo.fas.nyu.edu/galevolution
Continuum removal in H\alpha\ extragalactic measurements
We point out an important source of error in measurements of extragalactic
H-alpha emission and suggest ways to reduce it.
The H-alpha line, used for estimating star formation rates, is commonly
measured by imaging in a narrow band and a wide band, both which include the
line. The image analysis relies on the accurate removal of the underlying
continuum. We discuss in detail the derivation of the emission line's
equivalent width and flux for extragalactic extended sources, and the required
photometric calibrations. We describe commonly used continuum-subtraction
procedures, and discuss the uncertainties that they introduce.
Specifically, we analyse errors introduced by colour effects. We show that
the errors in the measured H-alpha equivalent width induced by colour effects
can lead to underestimates as large as 40% and overestimates as large as 10%,
depending on the underlying galaxy's stellar population and the
continuum-subtraction procedure used. We also show that these errors may lead
to biases in results of surveys, and to the underestimation of the cosmic star
formation rate at low redshifts (the low z points in the Madau plot). We
suggest a method to significantly reduce these errors using a single colour
measurement.Comment: 8 pages, 3 figures, MNRAS in pres
Studies of SARS virus vaccines
1. Intranasal vaccination using inactivated SARS coronavirus (SARS-CoV) vaccine with adjuvant can induce strong systemic (serum immunoglobulin [Ig] G) and respiratory tract local (tracheal-lung wash fluid IgA) antibody responses with neutralising activity. 2. RBD-Fc (protein-based vaccine) is able to induce effective neutralising antibodies able to provide protection from SARS-CoV infection in animal models. 3. A single dose of RBD-rAAV vaccination can induce adequate neutralising antibody against SARS-CoV infection. 4. Additional doses of vaccine increased the production of neutralising antibody 5-fold compared with a single dose. 5. RBD-rAAV vaccination provoked a prolonged antibody response with continually increasing levels of neutralising activity. 6. Intranasal vaccination with RBD-rAAV induced local IgA and systemic IgG neutralising antibodies and specific T-cell responses, able to protect against SARS-CoV infection in animal models. 7. When compared with the RBD-rAAV prime/boost vaccination, RBD-rAAV prime/RBD-peptide boost induced similar levels of Th1 and neutralising antibody responses that protected vaccinated mice from subsequent SARS-CoV challenges,but stronger Th2 and CTL responses. 8. Overall, our findings suggest that the inactivated vaccine, RBD-Fc and RBD-rAAV, can be further developed into effective and safe vaccines against SARS and that intranasal vaccination may be the preferred route of administration.published_or_final_versio
Activity and Process Stability of Purified Green Pepper (Capsicum annuum) Pectin Methylesterase
Pectin methylesterase (PME) from green bell peppers (Capsicum annuum) was extracted and purified by affinity chromatography on a CNBr-Sepharose-PMEI column. A single protein peak with pectin methylesterase activity was observed. For the pepper PME, a biochemical characterization in terms of molar mass (MM), isoelectric points (pI), and kinetic parameters for activity and thermostability was performed. The optimum pH for PME activity at 22 °C was 7.5, and its optimum temperature at neutral pH was between 52.5 and 55.0 °C. The purified pepper PME required the presence of 0.13 M NaCl for optimum activity. Isothermal inactivation of purified pepper PME in 20 mM Tris buffer (pH 7.5) could be described by a fractional conversion model for lower temperatures (55?57 °C) and a biphasic model for higher temperatures (58?70 °C). The enzyme showed a stable behavior toward high-pressure/temperature treatments. Keywords: Capsicum annuum; pepper; pectin methylesterase; purification; characterization; thermal and high-pressure stabilit
Global Star Formation Rate Density over 0.7<z<1.9
We determine the global star formation rate density at 0.7<z<1.9 using
emission-line selected galaxies identified in Hubble Space Telescope Near
Infrared Camera and Multi-Object Spectrograph (HST-NICMOS) grism spectroscopy
observations. Observing in pure parallel mode throughout HST Cycles 12 and 13,
our survey covers ~104 arcmin2 from which we select 80 galaxies with likely
redshifted Ha emission lines. In several cases, a somewhat weaker [OIII]
doublet emission is also detected. The Ha luminosity range of the emission-line
galaxy sample is 4.4 x 10^41 < L(Ha) < 1.5 x 10^43 erg/s. In this range, the
luminosity function is well described by a Schechter function with phi* =
(4.24\pm3.55) x 10^-3 Mpc^-3, L* = (2.88\pm1.58) x 10^42 erg/s, and alpha =
-1.39\pm0.43. We derive a volume-averaged star formation rate density of
0.138\pm0.058 Msun/yr/Mpc3 at z=1.4 without an extinction correction.
Subdividing the redshift range, we find star formation rate densities of
0.088\pm0.056 Msun/yr/Mpc3 at z=1.1 and 0.265\pm0.174 Msun/yr/Mpc3 at z=1.6.
The overall star formation rate density is consistent with previous studies
using Ha when the same average extinction correction is applied, confirming
that the cosmic peak of star formation occurs at z>1.5.Comment: Accepted for publication in Ap
Inactivation of myosin binding protein C homolog in zebrafish as a model for human cardiac hypertrophy and diastolic dysfunction
[[incitationindex]]SC
Studies of SARS virus vaccines
1. Intranasal vaccination using inactivated SARS coronavirus (SARS-CoV) vaccine with adjuvant can induce strong systemic (serum immunoglobulin [Ig] G) and respiratory tract local (tracheal-lung wash fluid IgA) antibody responses with neutralising activity. 2. RBD-Fc (protein-based vaccine) is able to induce effective neutralising antibodies able to provide protection from SARS-CoV infection in animal models. 3. A single dose of RBD-rAAV vaccination can induce adequate neutralising antibody against SARS-CoV infection. 4. Additional doses of vaccine increased the production of neutralising antibody 5-fold compared with a single dose. 5. RBD-rAAV vaccination provoked a prolonged antibody response with continually increasing levels of neutralising activity. 6. Intranasal vaccination with RBD-rAAV induced local IgA and systemic IgG neutralising antibodies and specific T-cell responses, able to protect against SARS-CoV infection in animal models. 7. When compared with the RBD-rAAV prime/boost vaccination, RBD-rAAV prime/RBD-peptide boost induced similar levels of Th1 and neutralising antibody responses that protected vaccinated mice from subsequent SARS-CoV challenges,but stronger Th2 and CTL responses. 8. Overall, our findings suggest that the inactivated vaccine, RBD-Fc and RBD-rAAV, can be further developed into effective and safe vaccines against SARS and that intranasal vaccination may be the preferred route of administration.published_or_final_versio
Creation and suppression of point defects through a kick-out substitution process of Fe in InP
Indium antisite defect In P-related photoluminescence has been observed in Fe-diffused semi-insulating (SI) InP. Compared to annealed undoped or Fe-predoped SI InP, there are fewer defects in SI InP obtained by long-duration, high-temperature Fe diffusion. The suppression of the formation of point defects in Fe-diffused SI InP can be explained in terms of the complete occupation by Fe at indium vacancy. The In P defect is enhanced by the indium interstitial that is caused by the kick out of In and the substitution at the indium site of Fe in the diffusion process. Through these Fe-diffusion results, the nature of the defects in annealed undoped SI InP is better understood. © 2002 American Institute of Physics.published_or_final_versio
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