2,084 research outputs found
The Effectiveness of California Assembly Bill 2109: Personal Belief Exemptions for Kindergarten Immunizations
The numbers of vaccine preventable diseases (VPDs) in the United States has declined with the development, administration, and effectiveness of vaccines during the 1970s and 1980s. As the eminent threat of VPDs to the public began to wane, parents started questioning the safety and necessity of vaccines. When parents were given the option of selecting personal belief exemption (PBE) waivers for state mandated immunizations for their incoming kindergarten children, an increase in PBEs and the number of VPD outbreaks began to occur. To counter the growing trend of PBEs, and to prevent outbreaks of VPDs in school settings and communities, California Assembly Bill2109 (AB 2109, 2012) was created to help educate parents about vaccine safety and VPDs. As of January 2014, California Assembly Bill2109 (AB 2109, 2012) mandated that parents seeking PBEs for state mandated immunizations for students entering kindergarten were required to receive education about vaccine safety and risks along with education regarding VPDs by a health care professional (AB 2109, 2012). The purpose of this study was to examine the effectiveness of AB 21 09 by examining data from the top ten most populous counties in California. Data was collected for the 2013-2014, 2014-2015, and 2015- 2016 school years to determine if AB 2109 directly impacted the number of PBEs for incoming kindergartners. This project determined that AB 2109 was significant in decreasing the number 3 of PBEs from the 2013-2014,2014-2015, and 2015-2016 school years by -23.4% in the ten most populous counties in California. Further research beyond this project is necessary to evaluate the continued impact of AB 2109 on PBEs and in decreasing the number of VPD outbreaks throughout California
The Non-Monotonic Dependence of Supernova and Remnant Formation on Progenitor Rotation
Traditional models of core collapse suggest the issue of successful versus
failed supernova explosions and neutron star versus black hole formation
depends monotonically on the mass (and metallicity) of the progenitor star.
Here we argue that the issue of success or failure of the explosion or other
possible outcomes may depend non--monotonically on the rotation of the
progenitor star even at fixed progenitor mass and composition. We have computed
"shellular" models of core collapse for a star of 15 M_solar with initial
central angular velocity, Omega_0, in the range 0.1 -- 8 rad/s until a few
hundred ms after bounce to explore qualitative trends. The non--monotonic
behavior will be manifested in the rotation of the proto--neutron star and
hence in the strength of the associated magnetic field that will be generated
by shear in that rotating environment. We estimate that our maximally rotating
and shearing models generate toroidal fields approaching or exceeding 10^17G,
strengths nearing dynamical significance.Comment: 20 pages, 6 figures, accepted for publication in The Astrophysical
Journal. Few typos are correcte
Extreme offspring ornamentation in American coots is favored by selection within families, not benefits to conspecific brood parasites
Offspring ornamentation typically occurs in taxa with parental care, suggesting that selection arising from social interactions between parents and offspring may underlie signal evolution. American coot babies are among the most ornamented offspring found in nature, sporting vividly orange-red natal plumage, a bright red beak, and other red parts around the face and pate. Previous plumage manipulation experiments showed that ornamented plumage is favored by strong parental choice for chicks with more extreme ornamentation but left unresolved the question as to why parents show the preference. Here we explore natural patterns of variation in coot chick plumage color, both within and between families, to understand the context of parental preference and to determine whose fitness interests are served by the ornamentation. Conspecific brood parasitism is common in coots and brood parasitic chicks could manipulate hosts by tapping into parental choice for ornamented chicks. However, counter to expectation, parasitic chicks were duller (less red) than nonparasitic chicks. This pattern is explained by color variation within families: Chick coloration increases with position in the egg-laying order, but parasitic eggs are usually the first eggs a female lays. Maternal effects influence chick coloration, but coot females do not use this mechanism to benefit the chicks they lay as parasites. However, within families, chick coloration predicts whether chicks become âfavoritesâ when parents begin control over food distribution, implicating a role for the chick ornamentation in the parental life-history strategy, perhaps as a reliable signal of a chickâs size or age.
(Includes Supporting information.
Magnetic Fields in Core Collapse Supernovae: Possibilities and Gaps
Spectropolarimetry of core collapse supernovae has shown that they are
asymmetric and often, but not universally, bi-polar. The Type IIb SN1993J and
similar events showed large scatter in the Stokes parameter plane.
Observational programs clearly have much more to teach us about the complexity
of asymmetric supernovae and the physics involved in the asymmetry. Jet-induced
supernova models give a typical jet/torus structure that is reminiscent of some
objects like the Crab nebula, SN1987A and perhaps Cas A. Jets, in turn, may
arise from the intrinsic rotation and magnetic fields that are expected to
accompany core collapse. We summarize the potential importance of the
magneto-rotational instability for the core collapse problem and sketch some of
the effects that large magnetic fields, ~10^{15} G, may have on the physics of
the supernova explosion. Open issues in the problem of multi-dimensional
magnetic core collapse are summarized and a critique is given of some recent
MHD collapse calculations.Comment: 20 pages, 2 figures, to appear in the proceedings of the INT workshop
"Open Issues in Understanding Core Collapse Supernovae," Seattle, 2004, ed.
T. Mezzacappa (World Scientific
Extreme offspring ornamentation in American coots is favored by selection within families, not benefits to conspecific brood parasites
Offspring ornamentation typically occurs in taxa with parental care, suggesting that selection arising from social interactions between parents and offspring may underlie signal evolution. American coot babies are among the most ornamented offspring found in nature, sporting vividly orange-red natal plumage, a bright red beak, and other red parts around the face and pate. Previous plumage manipulation experiments showed that ornamented plumage is favored by strong parental choice for chicks with more extreme ornamentation but left unresolved the question as to why parents show the preference. Here we explore natural patterns of variation in coot chick plumage color, both within and between families, to understand the context of parental preference and to determine whose fitness interests are served by the ornamentation. Conspecific brood parasitism is common in coots and brood parasitic chicks could manipulate hosts by tapping into parental choice for ornamented chicks. However, counter to expectation, parasitic chicks were duller (less red) than nonparasitic chicks. This pattern is explained by color variation within families: Chick coloration increases with position in the egg-laying order, but parasitic eggs are usually the first eggs a female lays. Maternal effects influence chick coloration, but coot females do not use this mechanism to benefit the chicks they lay as parasites. However, within families, chick coloration predicts whether chicks become âfavoritesâ when parents begin control over food distribution, implicating a role for the chick ornamentation in the parental life-history strategy, perhaps as a reliable signal of a chickâs size or age.
(Includes Supporting information.
MHD Simulations of Core Collapse Supernovae with Cosmos++
We performed 2D, axisymmetric, MHD simulations with Cosmos++ in order to
examine the growth of the magnetorotational instability (MRI) in core--collapse
supernovae. We have initialized a non--rotating 15 solar mass progenitor,
infused with differential rotation and poloidal magnetic fields. The collapse
of the iron core is simulated with the Shen EOS, and the parametric Ye and
entropy evolution. The wavelength of the unstable mode in the post--collapse
environment is expected to be only ~ 200 m. In order to achieve the fine
spatial resolution requirement, we employed remapping technique after the iron
core has collapsed and bounced.
The MRI unstable region appears near the equator and angular momentum and
entropy are transported outward. Higher resolution remap run display more
vigorous overturns and stronger transport of angular momentum and entropy. Our
results are in agreement with the earlier work by Akiyama et al. (2003) and
Obergaulinger et al. (2009).Comment: 3 pages, 2 figures. To appear in the proceedings of the "Deciphering
the Ancient Universe with Gamma-Ray Bursts", April 2010, Kyoto, Japan, eds.
N. Kawai and S. Nagataki (AIP
Tax Reform in Japan: The Case of Personal Taxes
In this paper, we conduct a theoretical analysis of personal taxes (defined to include consumption and income taxes), describe and evaluate the past and present structure of personal taxes in Japan, and based on our findings, make a number of policy recommendations about how to reform personal taxes in Japan. We find that the structure of Japan's current consumption and income taxes is problematic from the viewpoints of both efficiency and equity and propose a reform package that improves both the efficiency and equity of Japan's personal taxes and, at the same time, achieves fiscal reconstruction.
The Role of Nestling Acoustic Experience in Song Discrimination in a Sparrow
Oscine songbirds are an ideal system for investigating how early experience affects vocal behavior. Young songbirds face a challenging task: how to recognize and selectively learn only their own speciesâ song, often during a time-limited window. Because birds are capable of hearing birdsong very early in life, early exposure to song could plausibly affect recognition of appropriate models; however, this idea conflicts with the traditional view that song learning occurs only after a bird leaves the nest. Thus, it remains unknown whether natural variation in acoustic exposure prior to song learning affects the template for recognition. In a population where sister species, golden-crowned and white-crowned sparrows, breed syntopically, we found that nestlings discriminate between heterospecific and conspecific song playbacks prior to the onset of song memorization. We then asked whether natural exposure to more frequent or louder heterospecific song explained any variation in golden-crowned nestling response to heterospecific song playbacks. We characterized the amount of each speciesâ song audible in golden-crowned sparrow nests and showed that even in a relatively small area, the ratio of heterospecific to conspecific song exposure varies from 0 to 20%. However, although many songbirds hear and respond to acoustic signals before fledging, golden-crowned sparrow nestlings that heard different amounts of heterospecific song did not behave differently in response to heterospecific playbacks. This study provides the first evidence that song discrimination at the onset of song learning is robust to the presence of closely related heterospecifics in nature, which may be an important adaptation in sympatry between potentially interbreeding taxa
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