Elimination of cusps in dimension 4 and its applications

We study a class of homotopies between maps from 4-manifolds to surfaces which we call cusp merges. These homotopies naturally appear in the uniqueness problems for certain pictorial descriptions of 4-manifolds derived from maps to the 2-sphere (for example, broken Lefschetz fibrations, wrinkled fibrations, or Morse 2-functions). Our main results provide a classification of cusp merge homotopies in terms of suitably framed curves in the source manifold, as well as a fairly explicit description of a parallel transport diffeomorphism associated to a cusp merge homotopy. The latter is the key ingredient in understanding how the aforementioned pictorial descriptions change under homotopies involving cusp merges. We apply our methods to the uniqueness problem of surface diagrams of 4-manifolds and describe algorithms to obtain surface diagrams for total spaces of (achiral) Lefschetz fibrations and 4-manifolds of the form M×S1, where M is a 3-manifold. Along the way we provide extensive background material about maps to surfaces and homotopies thereof and develop a theory of parallel transport that generalizes the use of gradient flows in Morse theory

Scatter factor : molecular characteristics and effect on the invasiveness of epithelial cells

The generation of invasiveness in transformed cells represents an essential step of tumor progression. We have previously shown that MDCK epithelial cells, which are deprived of intracellular adhesion by the addition of anti-Arc-1/uvomorulin antibodies, become invasive for collagen gels and embryonal heart tissue (Behrens, J., M. M. Mareel, F. M. Van Roy, and W. Birchmeier. 1989. J. Cell Biol. 108: 2435-2447.). Here we examined whether invasiveness is also induced by scatter factor, which is known to dissociate epithelial cells (Stoker, M., E. Gherardi, M. Perryman, and J. Gray. 1987. Nature (Lond.). 327:239-242.). Scatter factor was purified to homogeneity from conditioned medium of human fibroblasts by heparin-Sepharose chromatography, followed by cation exchange chromatography, gel filtration, or preparative SDS gel electrophoresis. We found that scatter factor represents a 92,000 mol wt glycoprotein which, apparently, is converted by limited proteolysis into disulfide-linked 62,000 and 34/32,000 mol wt subunits. Reversed phase HPLC and sequence analysis of tryptic peptides confirmed the suggested molecular structure, and revealed further that scatter factor exhibits sequence similarities to hepatocyte growth factor and to plasminogen. Purified scatter factor in fact induces the invasiveness into collagen matrices of MDCK epithelial cells, and induces or promotes the invasiveness of a number of human carcinoma cell lines. Apparently, the effect on the human cells depends on their respective degree of differentiation, i.e., cell lines with a less pronounced epithelial phenotype were more susceptible to the factor. Scatter factor does not seem to influence synthesis, steady-state level, and phosphorylation of the cell adhesion molecule Arc-1/uvomorulin. Thus, scatter factor represents a clearly defined molecular species which induces, in vitro, the progression of epithelial cells to a more motile, i.e., invasive phenotype

Traditional male circumcision : Balancing cultural rights and the prevention of serious, avoidable harm.

PKThe right to participate in cultural practices should be protected. However, it is a limited right, and does not entail a right to activities that cause serious and avoidable harms. I argue that the harms currently resulting from traditional circumcision are very serious, and that we have an obligation to ensure that the practice is effectively regulated so as to minimise the

Validity of participant recorded pedometer step logs in free-living adults.

Purposes. The purposes of this study were to (1) examine the validity of participant recorded pedometer step logs, (2) examine the relationship between steps per day and percent bodyfat (% BF), and (3) examine differences in steps per day by BMI category (< 25 m/kg2 vs. ≥ 25 kg/m2). Methods . Participants (N = 89; Male: n = 29, age = 37.97 +/- 9.41 years, BMI = 25.87 +/- 4.42 kg/m2, % BF = 21.66 +/- 6.21%; Female: n = 60, age = 40.07 +/- 10.72, BMI = 24.83 +/- 4.72 kg/m 2, % BF = 33.73 +/- 8.11%) in this cross-sectional, descriptive study simultaneously wore a sealed pedometer, unsealed pedometer, and Actigraph accelerometer for nine consecutive days. Body composition was assessed via air-displacement plethysmography (BOD POD). Descriptive statistics, tests of equivalence, correlation coefficients, and independent t-tests were calculated. Three conditions were examined for validity: raw Actigraph steps per day (RAW) vs. participant recorded steps per day (PSD), Actigraph steps corrected for vehicular travel (CORRECTED) vs. PSD, and total accumulated steps from the sealed pedometer (SEALED) vs. total accumulated steps from the participant recorded pedometer (PTOT). Results. There was a strong correlation between RAW and PSD (r = 0.88, p < 0.0001). However, RAW and PSD were not equivalent. Similarly, CORRECTED and PSD resulted in a strong correlation (r = 0.88, p < 0.0001), but they were not equivalent. Comparing SEALED and PTOT indicated a strong correlation (r = 0.96, p < 0.0001) and equivalence. All correlations for steps per day and % BF were moderate (range: r = 0.40 to 0.45). There was a significant difference in steps per day by BMI category in PSD (p = 0.03), but not in RAW and CORRECTED. Conclusions. These results indicate (1) acceptable validity for participant recorded pedometer step logs, (2) moderate relationships between steps per day and % BF, and (3) a significant difference in steps per day by BMI category in PST, but not in RAW and CORRECTED. Future research should attempt to further explain the relationship between Actigraph and pedometer-derived steps

Algal culture studies for CELSS

Microalgae are well-suited as a component of a Closed Environmental Life Support System (CELSS), since they can couple the closely related functions of food production and atmospheric regeneration. The objective was to provide a basis for predicting the response of CELSS algal cultures, and thus the food supply and air regeneration system, to changes in the culture parameters. Scenedesmus growth was measured as a function of light intensity, and the spectral dependence of light absorption by the algae as well as algal respiration in the light were determined as a function of cell concentration. These results were used to test and confirm a mathematical model that describes the productivity of an algal culture in terms of the competing processes of photosynthesis and respiration. The relationship of algal productivity to cell concentration was determined at different carbon dioxide concentrations, temperatures, and light intensities. The maximum productivity achieved by an air-grown culture was found to be within 10% of the computed maximum productivity, indicating that CO2 was very efficiently removed from the gas stream by the algal culture. Measurements of biomass productivity as a function of cell concentration at different light intensities indicated that both the productivity and efficiency of light utilization were greater at higher light intensities

The use of Moses traditions in the Gospel of John: a contribution to John's use of the Old Testament

This thesis investigates the ways in which Moses traditions are used in the Gospel of John. The term "Moses traditions" is meant to refer to the stories connected with the person of Moses in Exodus, Leviticus, Numbers, and Deuteronomy. Later developments of these traditions are taken into account, if they are relevant to John's use of Moses traditions. The study addresses three areas of concern: First, the literary context and narrative significance of each instance of a use of a Moses tradition in John's Gospel is investigated. Secondly, the probability of the suggested links to the Old Testament Vorlagen is assessed. It is argued that in many cases the identification of a suggested link cannot be strictly separated from the interpretation of the link. Thirdly, the theological significance of each suggested link is presented. It is argued that the most significant theological inference from the use of Moses traditions in John is the sociological function of the christological use of Moses traditions. Although Moses traditions are used to illuminate the person of Jesus, the function of that use is time and again to define the identity of Christian believers in relation to mainstream Judaism. The introductory chapter presents a short survey of scholarly work on John's use of the OT. It also tackles the details involved in detecting and interpreting OT allusions in a NT text. Finally, it discusses the explicit use of the name "Moses" in John's Gospel and establishes the thesis of the sociological function of the use of Moses traditions. Chapter Two discusses the use of Sinai traditions in John 1 and 2. It is argued that Ex 33-34 provides the crucial OT background to Jn 1: 14-18, and that Ex 19-24 illuminates several details of John 1: 19-2: 11. Chapter Three follows the use of Passover traditions throughout the whole Gospel. It is argued that Passover traditions serve mainly to illuminate aspects of Jesus' death. Chapter Four presents the use of wilderness traditions in John 3 and 6-8. A multifaceted picture emerges that includes a variety of ways in which wilderness traditions are evoked. Also, an excursus is added that discusses the question of how John's use of the OT affects the theological value of the OT revelation. Chapter Five tackles several instances in which the prophet like Moses is evoked or in which Moses and Jesus are compared as persons. Chapter Six summarizes the main results of the study

Characterization of Photosynthetic Efficiency and Growth of Selected Microalgae in Dense Culture

An objective of the Aquatic Species Program is the development of large scale culturing systems for the production of fuels from lipid-rich microalgae. A major constraint to any such culturing system is the provision of sufficient light in the most economical manner possible, which has led to the use of shallow outdoor ponds that are illuminated using natural sunllght

A population-based case-control study on social factors and risk of testicular germ cell tumours

Objectives Incidence rates for testicular cancer have risen over the last few decades. Findings of an association between the risk of testicular cancer and social factors are controversial. The association of testicular cancer and different indicators of social factors were examined in this study.<p></p> Design Case–control study.<p></p> Setting Population-based multicentre study in four German regions (city states Bremen and Hamburg, the Saarland region and the city of Essen).<p></p> Participants The study included 797 control participants and 266 participants newly diagnosed with testicular cancer of which 167 cases were classified as seminoma and 99 as non-seminoma. The age of study participants ranged from 15 to 69 years.<p></p> Methods Social position was classified by educational attainment level, posteducational training, occupational sectors according to Erikson-Goldthorpe-Portocarrero (EGP) and the socioeconomic status (SES) on the basis of the International SocioEconomic Index of occupational status (ISEI). ORs and corresponding 95% CIs (95% CIs) were calculated for the whole study sample and for seminoma and non-seminoma separately.<p></p> Results Testicular cancer risk was modestly increased among participants with an apprenticeship (OR=1.7 (95% CI 1.0 to 2.8)) or a university degree (OR=1.6 (95% CI 0.9 to 2.8)) relative to those whose education was limited to school. Analysis of occupational sectors revealed an excess risk for farmers and farm-related occupations. No clear trend was observed for the analyses according to the ISEI-scale.<p></p> Conclusions Social factors based on occupational measures were not a risk factor for testicular cancer in this study. The elevated risk in farmers and farm-related occupations warrants further research including analysis of occupational exposures.<p></p&gt

The Arctic Sea ice in the CMIP3 climate model ensemble – variability and anthropogenic change

The strongest manifestation of global warming is observed in the Arctic. The warming in the Arctic during the recent decades is about twice as strong as in the global average and has been accompanied by a summer sea ice decline that is very likely unprecedented during the last millennium. Here, Arctic sea ice variability is analyzed in the ensemble of CMIP3 models. Complementary to several previous studies, we focus on regional aspects, in particular on the Barents Sea. We also investigate the changes in the seasonal cycle and interannual variability. In all regions, the models predict a reduction in sea ice area and sea ice volume during 1900–2100. Toward the end of the 21st century, the models simulate higher sea ice area variability in September than in March, whereas the variability in the preindustrial control runs is higher in March. Furthermore, the amplitude and phase of the sea ice seasonal cycle change in response to enhanced greenhouse warming. The amplitude of the sea ice area seasonal cycle increases due to the very strong sea ice area decline in September. The seasonal cycle amplitude of the sea ice volume decreases due to the stronger reduction of sea ice volume in March. Multi-model mean estimates for the late 20th century are comparable with observational data only for the entire Arctic and the Central Arctic. In the Barents Sea, differences between the multi-model mean and the observational data are more pronounced. Regional sea ice sensitivity to Northern Hemisphere average surface warming has been investigated