p-Adic and p-cotorsion completions of nilpotent groups

AbstractThe theory of cotorsion Abelian groups is extended to the category of nilpotent groups, and applications are given to the theory of p-adic completions and exactness properties of the p-adic completion functor. The p-cotorsion completion functor was first extended from Abelian to nilpotent groups by Bousfield and Kan, who defined and studied it using topological methods. We develop the theory group-theoretically, and additional results and applications

Revised protocols for baseline port surveys for introduced marine species - Survey design, sampling protocols and specimen handling

A prerequisite for any attempt to control the introduction and spread by shipping of non-indigenous marine pest species in Australian waters is knowledge of the current distribution and abundance of introduced species in Australian ports. This information base is lacking for a majority of Australian ports. The Australian Ballast Water Management Advisory Council (ABWMAC), the Standing Committee on Agriculture and Resource Management (SCARM), and the Australia and New Zealand Environment and Conservation Council (ANZECC) State of the Environment (SoE) Reporting Task Force, have all recognised the need for baseline studies to determine the extent to which introduced species have established in Australian waters. In response to these needs, the CSIRO Centre for Research on Introduced Marine Species (CRIMP) and various state agencies have commenced a national port survey program designed to define the occurrence of non-indigenous species in Australian ports. Given the number of agencies and research organisations that will potentially participate in a national port survey program, a high priority was given to developing a standardised set of survey methods that would provide a consistent basis on which to assess the introduced species status of individual ports. Surveys designed to identify all non-indigenous species in a port will inevitably be subject to scientific, logistic and cost constraints that will limit both their taxonomic and spatial scope. Recognition of these constraints led CRIMP to adopt a targeted approach that concentrates on a known group of species and provides a cost-effective collection of baseline data for all ports. While these surveys specifically target designated pest species, they are also designed to determine the distribution and abundance of other introduced species in a port. The surveys will also identify species of uncertain status (cryptogenic, that is not known if they are endemic or introduced) that are abundant in a port and/or are likely to become major pest species. This report reviews the general protocols developed by CRIMP for introduced species port surveys in 1996, and updates and provides evidence to support the recommended methodologies. The survey design and sampling protocols are outlined to encourage the adoption of a broad and consistent approach to the problem. Triggers for post survey monitoring regimes and factors influencing the frequency of resurveying are also discussed

Long Cycles in a Perturbed Mean Field Model of a Boson Gas

In this paper we give a precise mathematical formulation of the relation between Bose condensation and long cycles and prove its validity for the perturbed mean field model of a Bose gas. We decompose the total density $\rho=\rho_{{\rm short}}+\rho_{{\rm long}}$ into the number density of particles belonging to cycles of finite length ($\rho_{{\rm short}}$) and to infinitely long cycles ($\rho_{{\rm long}}$) in the thermodynamic limit. For this model we prove that when there is Bose condensation, $\rho_{{\rm long}}$ is different from zero and identical to the condensate density. This is achieved through an application of the theory of large deviations. We discuss the possible equivalence of $\rho_{{\rm long}}\neq 0$ with off-diagonal long range order and winding paths that occur in the path integral representation of the Bose gas.Comment: 10 page

Diffractive Dijet Production

We explore the diffractive interaction of a proton with an anti-proton which results in centrally produced dijets. This process has been recently studied at the Tevatron. We make predictions within an Ingelman-Schlein approach and compare them to the recent data presented by the CDF collaboration. Earlier calculations resulted in theoretical cross-sections which are much larger than those observed by CDF. We find that, after consideration of hadronisation effects and the parton shower, and using parton density functions extracted from diffractive deep inelastic scattering at HERA, it is possible to explain the CDF data. We need to assume a gap survival probability of around 10% and this is in good agreement with the value predicted by theory. We also find that the non-diffractive contribution to the process is probably significant in the kinematical region probed by the Tevatron.Comment: 12 pages, 6 figures, 3 table

A Project Module of E-Commerce Planning

The development of a pedagogy that integrates scholastic knowledge and practical skills of e-commerce for business students is imperative. Students typically learn e-commerce planning through course projects. This note provides tips for designing and teaching an e-commerce planning project module for the e-commerce course

The quantitative soil pit method for measuring belowground carbon and nitrogen stocks

Many important questions in ecosystem science require estimates of stocks of soil C and nutrients. Quantitative soil pits provide direct measurements of total soil mass and elemental content in depth-based samples representative of large volumes, bypassing potential errors associated with independently measuring soil bulk density, rock volume, and elemental concentrations. The method also allows relatively unbiased sampling of other belowground C and nutrient stocks, including roots, coarse organic fragments, and rocks. We present a comprehensive methodology for sampling these pools with quantitative pits and assess their accuracy, precision, effort, and sampling intensity as compared to other methods. At 14 forested sites in New Hampshire, nonsoil belowground pools (which other methods may omit, double-count, or undercount) accounted for upward of 25% of total belowground C and N stocks: coarse material accounted for 4 and 1% of C and N in the O horizon; roots were 11 and 4% of C and N in the O horizon and 10 and 3% of C and N in the B horizon; and soil adhering to rocks represented 5% of total B-horizon C and N. The top 50 cm of the C horizon contained the equivalent of 17% of B-horizon carbon and N. Sampling procedures should be carefully designed to avoid treating these important pools inconsistently. Quantitative soil pits have fewer sources of systematic error than coring methods; the main disadvantage is that because they are time-consuming and create a larger zone of disturbance, fewer observations can be made than with cores

Congenital diaphragmatic hernia: Comparison of animal models and relevance to the human situation

Congenital diaphragmatic hernia (CDH) occurs in 1 in 3,000 newborns. Mortality and morbidity are due to the amount of pulmonary hypoplasia (PH), the response on artificial ventilation and the presence of therapy-resistant pulmonary hypertension. The pathogenesis and etiology of CDH and its associated anomalies are still largely unknown despite all research efforts over the past years. Several animal models have been proposed to study CDH. In this review we compare surgical, pharmacological and transgenic models, and discuss their strengths and limitations to study PH

On the Tensor/Scalar Ratio in Inflation with UV Cutoff

Anisotropy of the cosmic microwave background radiation (CMB) originates from both tensor and scalar perturbations. To study the characteristics of each of these two kinds of perturbations, one has to determine the contribution of each to the anisotropy of CMB. For example, the ratio of the power spectra of tensor/scalar perturbations can be used to tighten bounds on the scalar spectral index. We investigate here the implications for the tensor/scalar ratio of the recent discovery (noted in astro-ph/0410139) that the introduction of a minimal length cutoff in the structure of spacetime does not leave boundary terms invariant. Such a cutoff introduces an ambiguity in the choice of action for tensor and scalar perturbations, which in turn can affect this ratio. We numerically solve for both tensor and scalar mode equations in a near-de-sitter background and explicitly find the cutoff dependence of the tensor/scalar ratio during inflation.Comment: 19 pages, 14 figures, to appear in Nucl. Phys. B; v4: typos corrected, matched with the published versio

Ten simple rules for interpreting and evaluating a meta-analysis

A systematic review with meta-analysis is often considered the highest level of evidence in ranking the literature. The term “systematic review” refers to the overall publication, while the term “meta-analysis” indicates that the review includes a statistical synthesis of results from at least 2 of the included studies. Not all systematic reviews include a meta-analysis, but meta-analyses are always within a systematic review. There are different types of metaanalyses in which statistical analysis can be performed, including network meta-analysis and Bayesian meta-analysis. While these meta-analysis methods can vary, the majority are “variations on a weighted average of the effect estimates from the different studies.

The extended empirical process test for non-Gaussianity in the CMB, with an application to non-Gaussian inflationary models

In (Hansen et al. 2002) we presented a new approach for measuring non-Gaussianity of the Cosmic Microwave Background (CMB) anisotropy pattern, based on the multivariate empirical distribution function of the spherical harmonics a_lm of a CMB map. The present paper builds upon the same ideas and proposes several improvements and extensions. More precisely, we exploit the additional information on the random phases of the a_lm to provide further tests based on the empirical distribution function. Also we take advantage of the effect of rotations in improving the power of our procedures. The suggested tests are implemented on physically motivated models of non-Gaussian fields; Monte-Carlo simulations suggest that this approach may be very promising in the analysis of non-Gaussianity generated by non-standard models of inflation. We address also some experimentally meaningful situations, such as the presence of instrumental noise and a galactic cut in the map.Comment: 15 pages, 6 figures, submitted to Phys. Rev.