On the distortion of knots on embedded surfaces

Our main result is a nontrivial lower bound for the distortion of some specific knots. In particular, we show that the distortion of the torus knot $T_{p,q}$ satisfies $\delta(T_{p,q})>\frac 1{160}\min(p,q)$. This answers a 1983 question of Gromov

Commentary on A Tale of Two States

While both California and Texas have experienced declines in teen birth rates over the past three decades, declines in California have been larger, particularly among Hispanic teens. Differences in state policies may have shaped this disparity, as suggested by Tortolero and her colleagues in their article “A Tale of Two States: What We Learn from California and Texas”. Fundamental differences exist between Texas and California in their approaches to sex education, access to family planning services for teens, and public-private partnerships. However, methodological challenges are present when drawing state comparisons, including the limitations of available public health data and the difficulty of disaggregating state characteristics from state policies. Based on their comparison of state data and policies, Tortolero and her colleagues issue sensible recommendations for reducing the teen birth rate in Texas. History suggests that state policies are most effective when political commitment is linked to scientifically effective approaches. Based on our understanding of the scientific literature, the most effective strategies for reducing rates of teen childbearing in Texas would be providing comprehensive school sexuality education and improving teen access to contraceptive services

Generalized control systems

Imperial Users onl

Vasotocin receptor expression in the brain and pituitary gland during the ovulatory cycle of the fowl

Vasotocin receptors are members of seven transmembrane spanning G-protein associated receptors. Several isoforms have been recognized in mammals and birds. It has been shown that VT-1 expression occurs primarily in the brain while VT-2 expression occurs mainly in the pituitary. There is no current evidence to support that both VTR-1 and -2 are found in a single tissue. Our goal in this experiment was to see if VT-1 and VT-2 receptor mRNA expression varied in known sites of expression over the period of the ovulatory cycle of broiler breeder hens. In order to study potential changes in VT-1 and VT-2 expression, birds were sacrificed at 3 hour intervals over a 24 hour period. Blood samples were drawn. After cervical dislocation, the brain, pituitary, shell gland, and kidney were removed. Plasma was stored at -20ºC prior to determination of corticosterone levels by radioimmuno assays. Isolated mRNA from the brains and the pituitaries was transferred to nylon membranes for northern slot blot analysis. cDNA for VT-1 and VT-2 was used to make random primed cDNA probes. Corticosterone levels significantly increased at 9 hours post oviposition relative to all other times. Neither VT-1 or VT- 2 expression showed any significant variation over the 24 hour cycle. Based on these results, we conclude that VT-1 and VT-2 steady state mRNA levels do not fluctuate dramatically over the ovulatory cycle of broiler breeder hens. Further work on membrane bound receptors and on circadian variations in membrane bound receptors in the brain and pituitary is currently underway of broiler breeder hens

Experimental methodologies to support aircraft icing analysis

The experimental methodologies are illustrated by graphs, charts and line drawings. Typical ultrasonic echo signals for dry and wet ice growth, ice accretion rates for various tunnel configurations, the experimental configuration for flight tests of the ultrasonic measuring system and heat balance models used to predict ice growth are among the topics that are illustrated and briefly discussed

Experimental measurements of heat transfer from an iced surface during artificial and natural cloud icing conditions

The heat transfer behavior of accreting ice surfaces in natural (flight test) and simulated (wind tunnel) cloud icing conditions were studied. Observations of wet and dry ice growth regimes as measured by ultrasonic pulse echo techniques were made. Observed wet and dry ice growth regimes at the stagnation point of a cylinder were compared with those predicted using a quasi steady state heat balance model. A series of heat transfer coefficients were employed by the model to infer the local heat transfer behavior of the actual ice surfaces. The heat transfer in the stagnation region was generally inferred to be higher in wind tunnel icing tests than in natural flight icing conditions

Minor\u27s Personal Injury Actions and Settlements in North Carolina

This Article addresses the issues that are peculiar to claims of minors in North Carolina. Persons who are the age of majority prosecute and settle claims that raise numerous substantive and procedural issues. These issues can be compounded, however, when the claimant is a minor. The distinct issues that arise with a minor’s claim include: that a minor is often held to a different standard of conduct; that other persons are held to a higher or different standard of conduct toward a minor; that other persons may have a duty to protect the minor; that courts generally protect the interests of minors; that minors cannot enter binding contracts; and that injuries to minors typically create claims in other parties, for example, the minor’s parents. This Article addresses the settlement and litigation of these claims. While this Article focuses on claims arising from a personal injury to the minor, many of the same legal issues are also raised in other contexts in which the minor’s interests are affected. As shown by many cases cited in this Article, much of the case law in North Carolina addressing the procedures for settling and adjudicating minors’ rights has arisen in the context of a minor’s interest in an estate or real property