8,757 research outputs found
Regional clinical registry data show increased incidence of cutaneous melanoma in Cape Town
Cutaneous melanoma is a skin tumour that continues to result in a high mortality rate, particularly in the case of thick tumours and those that are deeply invasive histologically. It occurs in all populations but is most common in fair-skinned individuals, especially those with skin types 1 and 2 that tan poorly or not at all. There is epidemiological evidence for the pathogenetic role of ultraviolet light, particularly intense childhood exposure, although the relationship is complex. Genetic factors also play a role, as exemplified by families with both atypical naevi and melanoma. The rising incidence of melanoma, noted initially in countries with high levels of UV light, appears to be levelling off or decreasing in some areas. The pattern of these trends is inconsistent, with even European countries showing great variation. An epidemiological study performed in Cape Town from 1990 to 1995 demonstrated an incidence of melanoma of 24.4 per 100 000 white people per annum. We conducted a methodologically identical study in the same geographical area after a 10-year interval, to identify whether there is a trend in the incidence of melanoma in this area
Final-State Phases in Baryon-Antibaryon Decays
The recent observation of the decay \ob \to \Lambda_c^+ \bar p suggests
that related decays may soon be visible at colliders. It is shown how
these decays can shed light on strong final-state phases and amplitudes
involving the spectator quark, both of which are normally expected to be small
in B decays.Comment: 14 pages, LaTeX, 2 figures, submitted to Phys. Rev. D, references and
discussion of helicity amplitudes adde
Enhanced Direct CP Violation in
We study direct CP violation in the hadronic decay , including the effect of mixing. We find
that the CP violating asymmetry is strongly dependent on the CKM matrix
elements, especially the Wolfenstein parameter . For fixed (the
effective parameter associated with factorization), the CP violating asymmetry,
, has a maximum of order when the invariant mass of the
pair is in the vicinity of the resonance. The
sensitivity of the asymmetry, , to is small. Moreover, if is
constrained using the latest experimental branching ratios from the CLEO
collaboration, we find that the sign of is always positive. Thus,
a measurement of direct CP violation in would
remove the mod ambiguity in .Comment: 37 pages, 7 figure
Urinary Levoglucosan as a Biomarker of Wood Smoke Exposure: Observations in a Mouse Model and in Children
BACKGROUND: Biomass smoke is an important source of particulate matter (PM), and much remains to be discovered with respect to the human health effects associated with this specific PM source. Exposure to biomass smoke can occur in one of two main categories: short-term exposures consist of periodic, seasonal exposures typified by communities near forest fires or intentional agricultural burning, and long-term exposures are chronic and typified by the use of biomass materials for cooking or heating. Levoglucosan (LG), a sugar anhydride released by combustion of cellulose-containing materials, is an attractive candidate as a biomarker of wood smoke exposure. OBJECTIVES: In the present study, Balb/c mice and children were assessed for LG in urine to determine its feasibility as a biomarker. METHODS: We performed urinary detection of LG by gas chromatography/mass spectrometry after intranasal instillations of LG or concentrated PM (mice) or biomass exposure (mice or humans). RESULTS: After instillation, we recovered most of the LG within the first 4 hr. Experiments using glucose instillation proved the specificity of our system, and instillation of concentrated PM from wood smoke, ambient air, and diesel exhaust supported a connection between wood smoke and LG. In addition, LG was detected in the urine of mice exposed to wood smoke. Finally, a pilot human study proved our ability to detect LG in urine of children. CONCLUSIONS: These results demonstrate that LG in the lungs is detectable in the urine of both mice and humans and that it is a good candidate as a biomarker of exposure to biomass smoke
From planning the port/city to planning the port-city : exploring the economic interface in European port cities
In last three decades, planning agencies of most ports have institutionally evolved into a (semi-) independent port authority. The rationale behind this process is that port authorities are able to react more quickly to changing logistical and spatial preferences of maritime firms, hence increasing the competitiveness of ports. Although these dedicated port authorities have proven to be largely successful, new economic, social, and environmental challenges are quickly catching up on these port governance models, and particularly leads to (spatial) policy âconflictsâ between port and city. This chapter starts by assessing this conflict and argue that the conflict is partly a result of dominantâoften also academicâspatial representations of the port city as two separate entities. To escape this divisive conception of contemporary port cities, this chapter presents a relational visualisation method that is able to analyse the economic interface between port and city. Based on our results, we reflect back on our proposition and argue that the core challenge today for researchers and policy makers is acknowledging the bias of port/city, being arguably a self-fulfilling prophecy. Hence, we turn the idea of (planning the) port/city conflicts into planning the port-cityâs strengths and weaknesses
The Big Society and the Conjunction of Crises: Justifying Welfare Reform and Undermining Social Housing
The idea of the âBig Societyâ can be seen as culmination of a long-standing debate about the regulation of welfare. Situating the concept within governance theory, the article considers how the UK coalition government has justified a radical restructuring of welfare provision, and considers its implications for housing provision. Although drawing on earlier modernization processes, the article contends that the genesis for welfare reform was based on an analysis that the government was forced to respond to a unique conjunction of crises: in morality, the state, ideology and economics. The government has therefore embarked upon a programme, which has served to undermine the legitimacy of the social housing sector (most notably in England), with detrimental consequences for residents and raising significant dilemmas for those working in the housing sector
Scherk-Schwarz Supersymmetry Breaking for Quasi-localized Matter Fields and Supersymmetry Flavor Violation
We examine the soft supersymmetry breaking parameters induced by the
Scherk-Schwarz (SS) boundary condition in 5-dimensional orbifold field theory
in which the quark and lepton zero modes are quasi-localized at the orbifold
fixed points to generate the hierarchical Yukawa couplings. In such theories,
the radion corresponds to a flavon to generate the flavor hierarchy and at the
same time plays the role of the messenger of supersymmetry breaking. As a
consequence, the resulting soft scalar masses and trilinear -parameters of
matter zero modes at the compactification scale are highly flavor-dependent,
thereby can lead to dangerous flavor violations at low energy scales. We
analyze in detail the low energy flavor violations in SS-dominated
supersymmetry breaking scenario under the assumption that the compactification
scale is close to the grand unification scale and the 4-dimensional effective
theory below the compactification scale is given by the minimal supersymmetric
standard model. Our analysis can be applied to any supersymmetry breaking
mechanism giving a sizable -component of the radion superfield, e.g. the
hidden gaugino condensation model.Comment: revtex4, 22 pages, some numerical errors are corrected in
phenomenological analysis, main conclusion does not chang
Cabibbo-suppressed non-leptonic B- and D-decays involving tensor mesons
The Cabibbo-suppressed non-leptonic decays of B (and D) mesons to final
states involving tensor mesons are computed using the non-relativistic quark
model of Isgur-Scora-Grinstein-Wise with the factorization hypothesis. We find
that some of these B decay modes, as B --> (K^*, D^*)D^*_2, can have branching
ratios as large as 6 x 10^{-5} which seems to be at the reach of future B
factories.Comment: Latex, 11 pages, to appear in Phys. Rev.
Are MNCs norm entrepreneurs or followers? The changing relationship between host country institutions and MNC HRM practices
Rooted in the literature on comparative capitalism, we examine the effects of host country institutions on the intra-organizational practices of multinational corporations (MNCs), using transnational level survey data, exploring change over time. We found that the less comprehensive institutional mediation of the Liberal Market Economies correlated with greater diversity and a more pronounced difference between domestic firms and foreign MNCs. However, rather than being the predicted norm entrepreneurs, MNCs tended to follow the lead of local firms in adjusting HRM policies and practices towards liberalization. Those most prone to challenging existing orders were in industries facing particular crises of competitiveness. Finally, we found that single regulatory features rather than complex assemblies of institutions exerted particularly strong effects on the individual firmsâ practices encompassed in this study
Testing QCD factorisation and charming penguins in charmless
We try a global fit of the experimental branching ratios and CP-asymmetries
of the charmless decays according to QCD factorisation. We find it
impossible to reach a satisfactory agreement, the confidence level (CL) of the
best fit is smaller than .1 %.
The main reason for this failure is the difficulty to accomodate several
large experimental branching ratios of the strange channels. Furthermore,
experiment was not able to exclude a large direct CP asymmetry in , which is predicted very small by QCD factorisation.
Trying a fit with QCD factorisation complemented by a charming-penguin inspired
model we reach a best fit which is not excluded by experiment (CL of about 8 %)
but is not fully convincing.
These negative results must be tempered by the remark that some of the
experimental data used are recent and might still evolve significantly.Comment: 21 pages, 4 figures; several typos corrected, added one footnote and
two references, comments added about PQCD. To appear in Phys.Rev.
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