Contact structures on open 3-manifolds

In this paper, we study contact structures on any open 3-manifold V which is the interior of a compact 3-manifold. To do this, we introduce proper contact isotopy invariants called the slope at infinity and the division number at infinity. We first prove several classification theorems for T^2 x [0, \infty), T^2 x R, and S^1 x R^2 using these concepts. This investigation yields infinitely many tight contact structures on T^2 x [0,\infty), T^2 x R, and S^1 x R^2 which admit no precompact embedding into another tight contact structure on the same space. Finally, we show that if V is irreducible and has an end of nonzero genus, then there are uncountably many tight contact structures on V that are not contactomorphic, yet are isotopic. Similarly, there are uncountably many overtwisted contact structures on V that are not contactomorphic, yet are isotopic.Comment: 18 pages, 3 figures, additions to intro, clearer statement of thm 1.1 (same proof), Modifications made to section 6 giving shorter proof of thm 1.2 and 1.

Municipal Conservation Outreach and Technical Assistance, Taylor, J

The New Hampshire Estuaries project awarded a grant of $24,700 to the Society for the Protection of New Hampshire Forests in May of 2002 for municipal conservation outreach and technical assistance in the area of municipal funds for permanent land conservation. SPNHF, working in close partnership with the Center for Land Conservation Assistance, conducted research into available mechanisms and funding sources for municipal conservation efforts. A publication summarizing the available options and providing information and case studies from a variety of New Hampshire towns was produced. Saving Special Places – Community Funding for Land Conservation, was distributed in December of 2002, just in time to assist towns seeking new municipal funding sources at the 2003 town meeting season. SPNHF/CLCA also provided a series of educational workshops on the topic of municipal fund raising for permanent land conservation. Eight workshops were held in the New Hampshire estuaries area, and seven were presented to at statewide events. Over 400 people attended the workshops. SPNHF/CLCA also provided technical assistance to twenty-four of the communities in the estuaries area over the period of the grant. Elements of the project were publicized in a wide range of print media in both statewide and estuary-area outlets.The education and outreach effort was quite successful. The number of towns applying land use change land monies to their conservation funds increased, as did the percent of the fund applied. The towns in the estuaries area that had the advantage of the new publication just as they were going into town meeting season with bond proposals in 2003 passed their bonds at a rate of 76$18,660,000 of new money available for conservation projects in those towns. Past the term of the grant, additional towns will be voting on increasing the amount of money from the Land Use Change Tax going to their conservation funds in 2004. Eight more towns in the estuaries area are considering open space bond proposals for the 2004 town meeting season, for a possible total of $19,600,000 in new funds for permanent land conservation. The coming challenge for the New Hampshire land conservation community will be to encourage the towns with these new sources of money to invest it wisely. Properties need to be selected according to guidelines that reflect a mix of natural resource values and local interests. Projects need to be conducted in a professional manner to insure long-term viability and excellent stewardship

Tracing baryons in the warm-hot intergalactic medium with broad Ly alpha absorption

We discuss physical properties and baryonic content of broad Ly alpha absorbers (BLAs) at low redshift. These absorption systems, recently discovered in high-resolution, high-signal to noise quasar absorption line spectra, possibly trace the warm-hot intergalactic medium (WHIM) in the temperature range between 10^5 and 10^6 K. To extend previous BLA measurements we have analyzed STIS data of the two quasars H 1821+643 and PG 0953+415 and have identified 13 BLA candidates along a total (unblocked) redshift path of dz=0.440. Combining our measurements with previous results for the lines of sight toward PG 1259+593 and PG 1116+215, the resulting new BLA sample consists of 20 reliably detected systems as well as 29 additional tentative cases, implying a BLA number density of dN/dz=22-53. We estimate that the contribution of BLAs to the baryon density at z=0 is Omega_b(BLA)>0.0027 h_70^-1 for absorbers with log (N/b)>11.3. This number indicates that WHIM broad Ly alpha absorbers contain a substantial fraction of the baryons in the local Universe. (Abridged abstract)Comment: 17 pages, 7 figures; Accepted for publication in A&

STEREOCHEMISTRY OF HEXENYL RADICAL CYCLIZATIONS WITH TERT-BUTYL AND RELATED LARGE GROUPS: SUBSTITUENT AND TEMPERATURE EFFECTS

The long held notion that hexenyl radicals bearing large substituents on the radical carbon cyclize to give 1,2-trans-substituted cyclopentanes is experimentally disproved by study of the radical cyclization of an assortment of simple and complex substrates coupled with careful product analysis and rigorous assignment of configurations. X-ray studies and syntheses of authentic samples establish that the published assignments for cis- and trans-1-tert-butyl-2-methylcyclopentane must be reversed. The original assignment based on catalytic hydrogenation of 1-tert-butyl-2-methylenecyclopentane was compromised by migration of the double bond prior to hydrogenation. The cyclization of 1-tert-butylhexenyl radical is moderately cis selective, and the selectivity is increased by geminal substitution on carbon 3. This selectivity trend is general and extends to relatively complex substrates. It has allowed Ihara to reduce the complexity of an important class of round trip radical cyclizations to make linear triquinanes to the point where two tricyclic products, cis-syn-cis and cis-anti-cis, account for about 80% of the products. However, the further increase in selectivity that was proposed by lowering the temperature is shown to be an artifact of the analysis methods and is not correct. This work solidifies "1,2-cis selectivity" in cyclizations of 1-subsituted hexenyl radicals as one of the most general stereochemical trends in radical cyclizations.ii

Determination of the Hubble Constant Using a Two-Parameter Luminosity Correction for Type Ia Supernovae

In this paper, we make a comprehensive determination of the Hubble constant $H_0$ by using two parameters - the B-V color and the rate of decline $\Delta m_{15}$ - to simultaneously standardize the luminosities of all nearby Cepheid-calibrated type Ia supernovae (SNe Ia) and those of a larger, more distant sample of 29 SNe Ia. Each group is treated in as similar a manner as possible in order to avoid systematic effects. A simultaneous $\chi ^2$ minimization yields a standardized absolute luminosity of the Cepheid-calibrated supernovae as well as the Hubble constant obtained from the more distant sample. We find $H_0 = 62 km/s Mpc^{-1}$ and a standardized absolute magnitude of -19.46. The sensitivity of $H_0$ to a metallicity dependence of the Cepheid-determined distances is investigated. The total uncertainty $\delta H_0$, dominated by uncertainties in the primary Cepheid distance indicator, is estimated to be 5 km/s Mpc^{-1}.Comment: To appear in Ap

Application of automobile emission control technology to light piston aircraft engines

The possibility was evaluated for achieving the EPA Standards for HC and CO emissions through the use of air-fuel ratio enleanment at selected power modes combined with improved air-fuel mixture preparation, and in some cases improved cooling. Air injection was also an effective approach for the reduction of HC and CO, particularly when combined with exhaust heat conservation techniques such as exhaust port liners

ABC of adolescence: sexual health, contraception, and teenage pregnancy

Sexual health becomes a new health priority in early adolescence. The sexual health of young people is a matter of intense public concern. The adverse consequences of unsafe sexual behaviour-such as pregnancy and sexually transmitted infections (STIs), including HIV infection-affect adolescents as well as adults. "Risk taking" behaviours are common when adolescents start being sexually intimate and are often linked with other health risk behaviours, such as substance misuse