5,476 research outputs found
Children’s Health in a Legal Framework
The interdisciplinary periodical Future of Children has dedicated an issue to children’s health policy. This contribution to the issue maps the legal landscape influencing policy choices. The authors demonstrate that in the U.S. legal system, parents have robust rights, grounded in the Constitution, to make decisions concerning their children’s health and medical treatment. Following from its commitment to parental rights, the system typically assumes the interests of parents and children are aligned, even when that assumption seems questionable. Thus, for example, parents who would limit their children’s access to health care on the basis of the parents’ religious belief have considerable latitude to do so, unless the child’s life is imminently threatened. There are some exceptions to this legal regime. Adolescents have the right to obtain some health services independently; in these contexts, social welfare needs such as pregnancy prevention trump parental rights. Minors also have access to abortion (although this right is more restricted than for adults). Moreover, the state has the power to intervene when parents place their children’s health at risk through abuse or neglect. A hallmark feature of the legal regime based on parental rights is that the state has no affirmative obligation to help parents care for their children’s health needs. This libertarian framing of the family-state relationship has profound implications for the development of public policy. To the extent the state provides support for families and children, it is doing so as a matter of policy choice (as with Medicaid and the Children’s Health Insurance Program) and not enforceable legal obligation. The importance of family autonomy thus results in a weak conception of shared responsibility for children. The framework also means that the state often takes a reactive approach to child wellbeing, intervening primarily when families have broken down or parents have seriously defaulted on their duties. Appreciation of the legal framework underscores the need to develop political support for any initiative to improve health services for children. Often, as this article shows, the state intervenes to promote children’s health only in response to compelling social welfare needs such as crime or disease prevention, or to crises in which parents abuse their children or fail to provide adequate care
Diamond chemical vapor deposition on optical fibers for fluorescence waveguiding
A technique has been developed for depositing diamond crystals on the
endfaces of optical fibers and capturing the fluorescence generated by
optically active defects in the diamond into the fiber. This letter details the
diamond growth on optical fibers and transmission of fluorescence through the
fiber from the nitrogen-vacancy (N-V) color center in diamond. Control of the
concentration of defects incorporated during the chemical vapor deposition
(CVD) growth process is also demonstrated. These are the first critical steps
in developing a fiber coupled single photon source based on optically active
defect centers in diamond.Comment: 10 pages, 3 figure
There is silver now, where once was gold
https://digitalcommons.library.umaine.edu/mmb-vp/4469/thumbnail.jp
The Message From The U. S. A.
https://digitalcommons.library.umaine.edu/mmb-vp/4892/thumbnail.jp
Multi-Gain-Stage InGaAs Avalanche Photodiode with Enhanced Gain and Reduced Excess Noise
We report the design, fabrication, and test of an InGaAs avalanche photodiode (APD) for 950-1650 nm wavelength sensing applications. The APD is grown by molecular beam epitaxy on InP substrates from lattice-matched InGaAs and InAlAs alloys. Avalanche multiplication inside the APD occurs in a series of asymmetric gain stages whose layer ordering acts to enhance the rate of electron-initiated impact ionization and to suppress the rate of hole-initiated ionization when operated at low gain. The multiplication stages are cascaded in series, interposed with carrier relaxation layers in which the electric field is low, preventing avalanche feedback between stages. These measures result in much lower excess multiplication noise and stable linear-mode operation at much higher avalanche gain than is characteristic of APDs fabricated from the same semiconductor alloys in bulk. The noise suppression mechanism is analyzed by simulations of impact ionization spatial distribution and gain statistics, and measurements on APDs implementing the design are presented. The devices employing this design are demonstrated to operate at linear-mode gain in excess of 6000 without avalanche breakdown. Excess noise characterized by an effective impact ionization rate ratio below 0.04 were measured at gains over 1000
Welcome To Our Heroes
https://digitalcommons.library.umaine.edu/mmb-vp/5350/thumbnail.jp
Voltage-controlled wavelength conversion by terahertz electro-optic modulation in double quantum wells
An undoped double quantum well (DQW) was driven with a terahertz (THz)
electric field of frequency \omega_{THz} polarized in the growth direction,
while simultaneously illuminated with a near-infrared (NIR) laser at frequency
\omega_{NIR}. The intensity of NIR upconverted sidebands
\omega_{sideband}=\omega_{NIR} + \omega_{THz} was maximized when a dc voltage
applied in the growth direction tuned the excitonic states into resonance with
both the THz and NIR fields. There was no detectable upconversion far from
resonance. The results demonstrate the possibility of using gated DQW devices
for all-optical wavelength shifting between optical communication channels
separated by up to a few THz.Comment: 3 pages, 6 figures. Figures 5 and 6 are JPEG files, figures/fig5.jpg
and fig6.jp
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