Fractional generalization of Fick's law: a microscopic approach

In the study of transport in inhomogeneous systems it is common to construct transport equations invoking the inhomogeneous Fick law. The validity of this approach requires that at least two ingredients be present in the system. First, finite characteristic length and time scales associated to the dominant transport process must exist. Secondly, the transport mechanism must satisfy a microscopic symmetry: global reversibility. Global reversibility is often satisfied in nature. However, many complex systems exhibit a lack of finite characteristic scales. In this Letter we show how to construct a generalization of the inhomogeneous Fick law that does not require the existence of characteristic scales while still satisfying global reversibility.Comment: 4 pages. Published versio

Continuous Time Random Walks in periodic systems: fluid limit and fractional differential equations on the circle

In this article, the continuous time random walk on the circle is studied. We derive the corresponding generalized master equation and discuss the effects of topology, especially important when Levy flights are allowed. Then, we work out the fluid limit equation, formulated in terms of the periodic version of the fractional Riemann-Liouville operators, for which we provide explicit expressions. Finally, we compute the propagator in some simple cases. The analysis presented herein should be relevant when investigating anomalous transport phenomena in systems with periodic dimensions.Comment: 14 pages, 1 figure. References added. Published versio

Gender- and age-related differences in clinical presentation and management of outpatients with stable coronary artery disease

<br>Introduction: Contemporary generalizable data on the demographics and management of outpatients with stable coronary artery disease (CAD) in routine clinical practice are sparse. Using the data from the CLARIFY registry we describe gender- and age-related differences in baseline characteristics and management of these patients across broad geographic regions.</br> <br>Methods: This international, prospective, observational, longitudinal registry enrolled stable CAD outpatients from 45 countries in Africa, Asia, Australia, Europe, the Middle East, and North, Central, and South America.</br> <br>Results: Baseline data were available for 33 280 patients. Mean (SD) age was 64 (10.5) years and 22.5% of patients were female. The prevalence of CAD risk factors was generally higher in women than in men. Women were older (66.6 vs 63.4 years), more frequently diagnosed with diabetes (33% vs 28%), hypertension (79% vs 69%), and higher resting heart rate (69 vs 67 bpm), and were less physically active. Smoking and a history of myocardial infarction were more common in men. Women were more likely to have angina (28% vs 20%), but less likely to have undergone revascularization procedures. CAD was more likely to be asymptomatic in older patients perhaps because of reduced levels of physical activity. Prescription of evidence-based medication for secondary prevention varied with age, with patients ≥ 75 years treated less often with beta blockers, aspirin and angiotensin-converting enzyme inhibitors than patients < 65 years.</br> <br>Conclusions: Important gender-related differences in clinical characteristics and management continue to exist in all age groups of outpatients with stable CAD.</br&gt

Tuning the Mass of Chameleon Fields in Casimir Force Experiments

We have calculated the chameleon pressure between two parallel plates in the presence of an intervening medium that affects the mass of the chameleon field. As intuitively expected, the gas in the gap weakens the chameleon interaction mechanism with a screening effect that increases with the plate separation and with the density of the intervening medium. This phenomenon might open up new directions in the search of chameleon particles with future long range Casimir force experiments

The clinical effectiveness of transurethral incision of the prostate : a systematic review of randomised controlled trials

The original publication is available at www.springerlink.com.Peer reviewedPostprin

Characterizing a new class of variability in GRS 1915+105 with simultaneous INTEGRAL/RXTE observations

We report on the analysis of 100 ks INTEGRAL observations of the Galactic microquasar GRS 1915+105. We focus on INTEGRAL Revolution number 48 when the source was found to exhibit a new type of variability as preliminarily reported in Hannikainen et al. (2003). The variability pattern, which we name $\xi$, is characterized by a pulsing behaviour, consisting of a main pulse and a shorter, softer, and smaller amplitude precursor pulse, on a timescale of 5 minutes in the JEM-X 3-35 keV lightcurve. We also present simultaneous RXTE data. From a study of the individual RXTE/PCA pulse profiles we find that the rising phase is shorter and harder than the declining phase, which is opposite to what has been observed in other otherwise similar variability classes in this source. The position in the colour-colour diagram throughout the revolution corresponds to State A (Belloni et al. 2000) but not to any previously known variability class. We separated the INTEGRAL data into two subsets covering the maxima and minima of the pulses and fitted the resulting two broadband spectra with a hybrid thermal--non-thermal Comptonization model. The fits show the source to be in a soft state characterized by a strong disc component below ~6 keV and Comptonization by both thermal and non-thermal electrons at higher energies.Comment: Accepted for publication in A&A. 11 pages, 10 figures, 4 in colour. Original figures can be found at http://www.astro.helsinki.fi/~diana/grs1915_rev48. Author affiliations correcte

Dynamic Scaling of Magnetic Flux Noise Near the KTB Transition in Overdamped Josephson Junction Arrays

We have used a dc Superconducting QUantum Interference Device to measure the magnetic flux noise generated by the equilibrium vortex density fluctuations associated with the Kosterlitz-Thouless-Berezinskii (KTB) transition in an overdamped Josephson junction array. At temperatures slightly above the KTB transition temperature, the noise is white for $f<f_\xi$ and scales as $1/f$ for $f>f_\xi$. Here $f_\xi\propto\xi^{-z}$, where $\xi$ is the correlation length and $z$ is the dynamic exponent. Moreover, when all frequencies are scaled by $f_\xi$, data for different temperatures and frequencies collapse on to a single curve. In addition, we have extracted the dynamic exponent $z$ and found $z=1.98\pm0.03$.Comment: 5 pages, LaTeX (REVTeX) format, requires epsfig and amstex style files. 3 figures included. Tentatively scheduled for publication in Physical Review Letters, 18 March, 199

Fluctuation-dissipation theorem and flux noise in overdamped Josephson junction arrays

The form of the fluctuation-dissipation theorem for a resistively shunted Josephson juction array is derived with the help of the method which explicitely takes into acoount screening effects. This result is used to express the flux noise power spectrum in terms of frequency dependent sheet impedance of the array. The relation between noise amplitude and parameters of the detection coil is analysed for the simplest case of a single-loop coil.Comment: ReVTeX, 8 page

Cytoglobin is upregulated by tumour hypoxia and silenced by promoter hypermethylation in head and neck cancer

Background: Cytoglobin (Cygb) was first described in 2002 as an intracellular globin of unknown function. We have previously shown the downregulation of cytoglobin as a key event in a familial cancer syndrome of the upper aerodigestive tract. Methods: Cytoglobin expression and promoter methylation were investigated in sporadic head and neck squamous cell carcinoma (HNSCC) using a cross-section of clinical samples. Additionally, the putative mechanisms of Cygb expression in cancer were explored by subjecting HNSCC cell lines to hypoxic culture conditions and 5-aza-2-deoxycitidine treatment. Results: In clinically derived HNSCC samples, CYGB mRNA expression showed a striking correlation with tumour hypoxia (measured by HIF1A mRNA expression P=0.013) and consistent associations with histopathological measures of tumour aggression. CYGB expression also showed a marked negative correlation with promoter methylation (P=0.018). In the HNSCC cell lines cultured under hypoxic conditions, a trend of increasing expression of both CYGB and HIF1A with progressive hypoxia was observed. Treatment with 5-aza-2-deoxycitidine dramatically increased CYGB expression in those cell lines with greater baseline promoter methylation. Conclusion: We conclude that the CYGB gene is regulated by both promoter methylation and tumour hypoxia in HNSCC and that increased expression of this gene correlates with clincopathological measures of a tumour's biological aggression.</p