Could the Hercules satellite be a stellar stream in the Milky Way halo?

We investigate the possibility that Hercules, a recently discovered Milky Way (MW) satellite, is a stellar stream in the process of formation. This hypothesis is motivated by Hercules' highly elongated shape as well as the measurement of a tentative radial velocity gradient along its body. The application of simple analytical techniques on radial velocity data of its member stars provides tight constraints on the tangential velocity of the system (v_t = -16^{+6}_{-22} km/s, relative to the Galactic Standard of Rest). Combining this with its large receding velocity (145 km/s) and distance (138 kpc) yields an orbit that would have taken Hercules to within 6^{+9}_{-2} kpc of the Galactic centre approximately 0.6 Gyr ago. This very small perigalacticon can naturally explain the violent tidal destruction of the dwarf galaxy in the MW's gravitational potential, inducing its transformation into a stellar stream.Comment: Conference proceedings of "A Universe of dwarf galaxies: Observations, Theories, Simulations" held in Lyon, France (June 14-18, 2010

Volatility and Agent Adaptability in a Self-Organizing Market

We present results for the so-called `bar-attendance' model of market behavior: $p$ adaptive agents, each possessing $n$ prediction rules chosen randomly from a pool, attempt to attend a bar whose cut-off is $s$. The global attendance time-series has a mean near, but not equal to, $s$. The variance, or `volatility', can show a minimum with increasing adaptability of the individual agents.Comment: 8 pages, 3 figs. [email protected], [email protected]

Chemically driven switches for online detection of pH changes in microfluidic devices

The internal walls of microfabricated fluidic channels were functionalized with a selfassembled monolayer of Rhodamine B lactam. This molecule has the capability to interconvert between its open fluorescent amide form and the closed non-fluorescent lactam form upon changes of the pH conditions. The interconversion (switch) between the two reversible forms is achieved by addition of an acid or a base and is consistent with a reaction mechanism of the first order. This paper describes the online observation of such fluorescent switch covalently anchored to the channel and proposes this method as a possible sensor for the monitoring of pH changes in microreactors

Short-term and long-term outcomes in 133 429 emergency patients admitted with angina or myocardial infarction in Scotland, 1990-2000: population-based cohort study

Objective: To analyse short- and long-term outcomes and prognostic factors in a large population-based cohort of unselected patients with a first emergency admission for suspected acute coronary syndrome between 1990 and 2000 in Scotland. Methods: All first emergency admissions for acute myocardial infarction (AMI) and all first emergency admissions for angina (the proxy for unstable angina) between 1990 and 2000 in Scotland (population 5.1 million) were identified. Survival to five years was examined by Cox multivariate modelling to examine the independent prognostic effects of diagnosis, age, sex, year of admission, socioeconomic deprivation and co-morbidity. Results: In Scotland between 1990 and 2000, 133 429 individual patients had a first emergency admission for suspected acute coronary syndrome: 96 026 with AMI and 37 403 with angina. After exclusion of deaths within 30 days, crude five-year case fatality was similarly poor for patients with angina and those with AMI (23.9% v 21.6% in men and 23.5% v 26.0% in women). The longer-term risk of a subsequent fatal or non-fatal event in the five years after first hospital admission was high: 54% in men after AMI (53% in women) and 56% after angina (49% in women). Event rates increased threefold with increasing age and 20–60% with different co-morbidities, but were 11–34% lower in women. Conclusions: Longer-term case fatality was similarly high in patients with angina and in survivors of AMI, about 5% a year. Furthermore, half the patients experienced a fatal or non-fatal event within five years. These data may strengthen the case for aggressive secondary prevention in all patients presenting with acute coronary syndrome

Role of shape and localized resonances in extraordinary transmission through periodic arrays of subwavelength holes: Experiment and theory

The effect of the aspect ratio of rectangular holes on the transmissivity of periodic arrays of subwavelength holes in optically thick metal films is investigated. The transmissivity is found to be highly dependent on the aspect ratio of the holes. Moreover, the wavelengths of maximum transmissivity show a monotonous shift as a function of the aspect ratio of the holes. We attribute the enhanced transmission of the periodic arrays to an interplay of surface plasmons at the surface of the metal and shape resonances (also known as localized modes) inside the holes. The importance of the shape resonances was confirmed by a comparison of transmission through periodic hole arrays and through randomly distributed holes. Dispersion curves of periodic and random hole arrays confirmed the existence of shape resonance as well. We suggest that the localized modes effectively act as waveguides and increase the coupling efficiency of surface plasmons between both sides of the film, which results in a higher transmissivity. The shift of the maxima of the transmissivity may in part be explained by the spectral position of the localized modes in the individual holes. Finally measurements on similar patterns in Ni and Ag revealed that the occurrence of shape resonances is independent of the material of the film

National survey of the prevalence, incidence, primary care burden, and treatment of heart failure in Scotland

Objective: To examine the epidemiology, primary care burden, and treatment of heart failure in Scotland, UK. Design: Cross sectional data from primary care practices participating in the Scottish continuous morbidity recording scheme between 1 April 1999 and 31 March 2000. Setting: 53 primary care practices (307 741 patients). Subjects: 2186 adult patients with heart failure. Results: The prevalence of heart failure in Scotland was 7.1 in 1000, increasing with age to 90.1 in 1000 among patients 85 years. The incidence of heart failure was 2.0 in 1000, increasing with age to 22.4 in 1000 among patients 85 years. For older patients, consultation rates for heart failure equalled or exceeded those for angina and hypertension. Respiratory tract infection was the most common co-morbidity leading to consultation. Among men, 23% were prescribed a ß blocker, 11% spironolactone, and 46% an angiotensin converting enzyme inhibitor. The corresponding figures for women were 20% (p = 0.29 versus men), 7% (p = 0.02), and 34% (p < 0.001). Among patients < 75 years 26% were prescribed a β blocker, 11% spironolactone, and 50% an angiotensin converting enzyme inhibitor. The corresponding figures for patients 75 years were 19% (p = 0.04 versus patients < 75), 7% (p = 0.04), and 33% (p < 0.001). Conclusions: Heart failure is a common condition, especially with advancing age. In the elderly, the community burden of heart failure is at least as great as that of angina or hypertension. The high rate of concomitant respiratory tract infection emphasises the need for strategies to immunise patients with heart failure against influenza and pneumococcal infection. Drugs proven to improve survival in heart failure are used less frequently for elderly patients and women

Shape resonances in extraordinary transmission

The paper focuses on the extraordinary transmission phenomenon, an example of plasmonics. In a periodic arrangement of sub-wavelength holes in a metal film the transmitted fraction of the incident light exceeds the open air fraction of the film for certain colours. This enhanced transmission has been attributed to a resonant excitation of surface plasmons set up by the periodicity of the array. But by merely changing the shape of the sub-wavelength holes from circular to rectangular can affect the extraordinary transmission

Fliess’s Kappa: konsesus kesepakatan pakar bagi bakat bekerja pelajar TVET di universiti teknikal

Bakat bekerja pelajar kearah negara berpendapatan tinggi merupakan cabaran besar kepada negara Malaysia menjelang 2020. Pelbagai usaha yang perlu dilakukan dalam menyediakan graduan yang berbakat serta mempunyai kepakaran dalam bidang yang diceburi bagi memastikan peluang pendidikan yang tepat kepada pelajar. Ini jelas menunjukkan bakat bekerja perlu di pertingkatan dalam mempersiap sediakan kepada graduan dengan ilmu mereka cipta sesuatu yang baru dan berinovasi. Bakat bekerja ini adalah dapat membantu negara mencapai status negara maju disamping meningkatkan kualiti hidup graduan apabila bekerja di industri kelak. Kajian ini dilakukan adalah bagi menentu sahkan domain dan komponen bakat bekerja berdasarkan konsesus kesepakatan bersama 5 orang pakar yang terlibat dalam kajian. Tujuan kajian ini adalah mengukur tahap persetujuan pakar melalui kaedah pengiraan Fliess's kappa. Hasil dapatan menunjukkan kelima-lima pakar telah sepakat terdapat 42 komponen yang telah dipersetujui dan 4 komponen yang tidak dipersetujui oleh pakar yang terlibat bagi 6 domain bakat bekerja yang terlibat. Hasil kajian ini dapat dijadikan rujukan dalam meningkatkan bakat bekerja pelajar bagi menyumbang ke arah negara maju dalam memenuhi permintaan industri dan menambah peluang bagi kemajuan kerjaya untuk pembangunan TVET negara

Mott scattering of polarized electrons in a strong laser field

We present analytical and numerical results of the relativistic calculation of the transition matrix element $S_{fi}$ and differential cross section for Mott scattering of initially polarized Dirac particles (electrons) in the presence of strong laser field with linear polarization. We use exact Dirac-Volkov wave functions to describe the dressed electrons and the collision process is treated in the first Born approximation. The influence of the laser field on the degree of polarization of the scattered electron is reported.Comment: 12 pages, 11 figures, Revte

An NMR-based nanostructure switch for quantum logic

We propose a nanostructure switch based on nuclear magnetic resonance (NMR) which offers reliable quantum gate operation, an essential ingredient for building a quantum computer. The nuclear resonance is controlled by the magic number transitions of a few-electron quantum dot in an external magnetic field.Comment: 4 pages, 2 separate PostScript figures. Minor changes included. One reference adde