Root numbers and ranks in positive characteristic

For a global field K and an elliptic curve E_eta over K(T), Silverman's specialization theorem implies that rank(E_eta(K(T))) <= rank(E_t(K)) for all but finitely many t in P^1(K). If this inequality is strict for all but finitely many t, the elliptic curve E_eta is said to have elevated rank. All known examples of elevated rank for K=Q rest on the parity conjecture for elliptic curves over Q, and the examples are all isotrivial. Some additional standard conjectures over Q imply that there does not exist a non-isotrivial elliptic curve over Q(T) with elevated rank. In positive characteristic, an analogue of one of these additional conjectures is false. Inspired by this, for the rational function field K = kappa(u) over any finite field kappa with odd characteristic, we construct an explicit 2-parameter family E_{c,d} of non-isotrivial elliptic curves over K(T) (depending on arbitrary c, d in kappa^*) such that, under the parity conjecture, each E_{c,d} has elevated rank.Comment: 40 pages; last version; to appear in Adv. Mat

The Bradford & Airedale Health of Men initiative: a study of its effectiveness in engaging with men

The Health of Men (HoM) network received funding from the Big Lottery Fund in 2003 to establish a five year programme of dedicated work with men and boys. This enabled a team of practitioners to be creative and to build upon their existing skills to generate models of working with those men in the community that are usually seen as hard to reach. The research which has accompanied of the work of team has explored why men use these new services and has demonstrated the following: • Men do care about their health • Men are willing and able to engage with their health when services are tailored to their needs • Men from different culture groups and socio-economic backgrounds who are normally seen as hard to reach were accessed. • A model encompassing a dedicated team working with men is worthy of further development Much has been learnt from this project that has great relevance to the local Primary Care Trust (PCT), but has also proved a great source of information for the development of services to men on a Regional, National and International level

Search for rare leptonic B decays at the Tevatron

Results of a search for the Flavor-Changing Neutral Current decay $B^0_{s,d} \to \mu^+ \mu^-$ using $p\bar{p}$ collision data at $\sqrt{s}=1.96$ TeV collected at Fermilab Tevatron collider by the CDF and D{\O}detectors are presented. CDF reports upper limits on ${\cal B} (B^0_{s} \to \mu^+ \mu^-) \leq 7.5 \cdot10^{-7}$ and ${\cal B}(B^0_{d} \to \mu^+ \mu^-) \leq 1.9 \cdot10^{-7}$ at the 95% C.L. using 171 pb$^{-1}$. The D{\O}Collaboration used 240 pb$^{-1}$ to set an even more stringent limit on the branching ratio for $B^0_{s} \to \mu^+ \mu^-$ of $5.0\cdot 10^{-7}$ at the 95% C.L.Comment: 5 pages, 2 figures, submitted to DPF 2004 conference proceedings, UC Riverside, C

A Comparison of Decision-Making Variables Used by Dual-Career Couples

The increasing number of households transitioning from traditional oneworker families to dual-career families has created complex issues for the individual, the family, employers, and society in general. Learning more about how these dual-career couples make decisions will help provide a better capability to tailor counseling needs to these individuals, as well as guide policy for employers. This study examined 115 dual-career spouses from four different occupational groups: Air Force, Army, Navy, and civilian organizations. The participants consisted of 54 husbands and 61 wives who completed a questionnaire designed for this study. The survey measured 12 decision-making variables identified in a previous study by the author. Specifically, this study investigated whether dual-career couples ascribe the same importance to decision-making variables and if the weights they assigned to these variables differ as a function of the type of career. Results of the multivariate and univariate analyses of variance suggested that there are signi6cant differences between gender groups and among career groups. These differences were discussed along with the implications of these findings for both the employers and counselors

Abundance of small individuals influences the effectiveness of processing techniques for deep-sea nematodes

Nematodes are the most abundant metazoans of deep-sea benthic communities, but knowledge of their distribution is limited relative to larger organisms. Whilst some aspects of nematode processing techniques, such as extraction, have been extensively studied, other key elements have attracted little attention. We compared the effect of (1) mesh size (63, 45, and 32 μm) on estimates of nematode abundance, biomass, and body size, and (2) microscope magnification (50 and 100×) on estimates of nematode abundance at bathyal sites (250-3100 m water depth) on the Challenger Plateau and Chatham Rise, south-west Pacific Ocean. Variation in the effectiveness of these techniques was assessed in relation to nematode body size and environmental parameters (water depth, sediment organic matter content, %silt/clay, and chloroplastic pigments). The 63-μm mesh retained a relatively low proportion of total nematode abundance (mean ±SD = 55 ±9%), but most of nematode biomass (90 ± 4%). The proportion of nematode abundance retained on the 45-μm mesh in surface (0-1 cm) and subsurface (1-5 cm) sediment was significantly correlated (P < 0.01) with %silt/clay (R² = 0.39) and chloroplastic pigments (R² = 0.29), respectively. Variation in median nematode body weight showed similar trends, but relationships between mean nematode body weight and environmental parameters were either relatively weak (subsurface sediment) or not significant (surface sediment). Using a low magnification led to significantly lower (on average by 43%) nematode abundance estimates relative to high magnification (P < 0.001), and the magnitude of this difference was significantly correlated (P < 0.05) with total nematode abundance (R²p = 0.53) and the number of small (≤ 250 μm length) individuals (R²p = 0.05). Our results suggest that organic matter input and sediment characteristics influence the abundance of small nematodes in bathyal communities. The abundance of small individuals can, in turn, influence abundance estimates obtained using different mesh sizes and microscope magnifications