456 research outputs found
Reviving Marriage in America: Strategies for Donors
In 1997 a group of Tennessee businessmen began to talk about the direction of their city. "We wanted to know how we could really make a difference in Chattanooga," says Hugh O. Maclellan Jr., president of the Maclellan Foundation. "We realized that the city's biggest problem was the breakdown of families, and that every part of Chattanooga was being affected by it."Maclellan and his colleagues confronted grim statistics that showed Chattanooga families were suffering from unusually high rates of divorce, absentee fathers and teen pregnancies, which were hurting not only the individuals immediately involved, but the community as a whole. The numbers told the story:The divorce rate in Chattanooga was 50 percent higher than the national average. (The state of Tennessee as a whole ranked fourth worst in the nation for divorce.) Chattanooga had the fifth-worst out-of-wedlock birth rate of 128 leading cities in the United States. A 1994 study showed 50 percent of births in the city and 39 percent of births in the county were to unwed mothers. One in three Tennessee families were headed by a single parent, compared to one in four nationwide; in 2000, the state ranked eighth worst in the nation
Synthesis and Optimisation of P3 Substituted Vinyl Sulfone-Based Inhibitors as Anti-Trypanosomal Agents
A series of lysine-based vinyl sulfone peptidomimetics were synthesised and evaluated for anti-trypanosomal activity against bloodstream forms of T. brucei. This focused set of compounds, varying in the P3 position, were accessed in a divergent manner from a common intermediate (ammonium salt 8). Several P3 analogues exhibited sub-micromolar EC50 values, with thiourea 14, urea 15 and amide 21 representing the most potent anti-trypanosomal derivatives of the series. In order to establish an in vitro selectivity index the most active anti-trypanosomal compounds were also assessed for their impact on cell viability and cytotoxity effects in mammalian cells. Encouragingly, all compounds only reduced cellular metabolic activity in mammalian cells to a modest level and little, or no cytotoxicity, was observed with the series
Optimisation of Scalable Ion-Cavity Interfaces for Quantum Photonic Networks
In the design optimisation of ion-cavity interfaces for quantum networking
applications, difficulties occur due to the many competing figures of merit and
highly interdependent design constraints, many of which present `soft-limits',
amenable to improvement at the cost of engineering time. In this work we
present a systematic approach to this problem which offers a means to identify
efficient and robust operating regimes, and to elucidate the trade-offs
involved in the design process, allowing engineering efforts to be focused on
the most sensitive and critical parameters. We show that in many relevant cases
it is possible to approximately separate the geometric aspects of the
cooperativity from those associated with the atomic system and the mirror
surfaces themselves, greatly simplifying the optimisation procedure. Although
our approach to optimisation can be applied to most operating regimes, here we
consider cavities suitable for typical ion trapping experiments, and with
substantial transverse misalignment of the mirrors. We find that cavities with
mirror misalignments of many micrometres can still offer very high photon
extraction efficiencies, offering an appealing route to the scalable production
of ion-cavity interfaces for large scale quantum networks
The convex Positivstellensatz in a free algebra
Given a monic linear pencil L in g variables let D_L be its positivity
domain, i.e., the set of all g-tuples X of symmetric matrices of all sizes
making L(X) positive semidefinite. Because L is a monic linear pencil, D_L is
convex with interior, and conversely it is known that convex bounded
noncommutative semialgebraic sets with interior are all of the form D_L. The
main result of this paper establishes a perfect noncommutative
Nichtnegativstellensatz on a convex semialgebraic set. Namely, a noncommutative
polynomial p is positive semidefinite on D_L if and only if it has a weighted
sum of squares representation with optimal degree bounds: p = s^* s + \sum_j
f_j^* L f_j, where s, f_j are vectors of noncommutative polynomials of degree
no greater than 1/2 deg(p). This noncommutative result contrasts sharply with
the commutative setting, where there is no control on the degrees of s, f_j and
assuming only p nonnegative, as opposed to p strictly positive, yields a clean
Positivstellensatz so seldom that such cases are noteworthy.Comment: 22 page
ACE-ASIA - Regional climatic and atmospheric chemical effects of Asian dust and pollution
Although continental-scale plumes of Asian dust and pollution reduce the amount of solar radiation reaching the earth's surface and perturb the chemistry of the atmosphere, our ability to quantify these effects has been limited by a lack of critical observations, particularly of layers above the surface. Comprehensive surface, airborne, shipboard, and satellite measurements of Asian aerosol chemical composition, size, optical properties, and radiative impacts were performed during the Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia) study. Measurements within a massive Chinese dust storm at numerous widely spaced sampling locations revealed the highly complex structure of the atmosphere, in which layers of dust, urban pollution, and biomass-burning smoke may be transported long distances as distinct entities or mixed together. The data allow a first-time assessment of the regional climatic and atmospheric chemical effects of a continental-scale mixture of dust and pollution. Our results show that radiative flux reductions during such episodes are sufficient to cause regional climate change
Indications for thyroid FNA and pre-FNA requirements: A synopsis of the National Cancer Institute Thyroid Fine-Needle Aspiration State of the Science Conference
The National Cancer Institute (NCI) sponsored the NCI Thyroid Fine-Needle Aspiration (FNA) State of the Science Conference on October 22–23, 2007 in Bethesda, MD. The 2-day meeting was accompanied by a permanent informational website and several on-line discussions between May 1 and December 15, 2007 ( http://thyroidfna.cancer.gov ). This document summarizes the indications for performing an FNA of a nodule discovered by physical examination or an imaging study; the indications for using ultrasound versus palpation for guidance when performing a thyroid FNA; the issues surrounding informed consent for thyroid FNA; and the information required on a requisition form that accompanies a thyroid FNA specimen. ( http://thyroidfna.cancer.gov/pages/info/agenda/ ) Diagn. Cytopathol. 2008;36:390–399. © 2008 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/58658/1/20827_ftp.pd
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