Ewing’s Sarcoma

Ewing’s sarcoma is the second most common malignant tumor of the bone occurring in children and adolescents. Typically, patients present between the ages of 10 and 20, with the disease having a slight predilection for males.1 Tumors often arise in the mid-shaft with the femur being the most frequently affected bone. The most common chromosome translocation, t(11;22)(q24;q12), occurs between the EWS gene and the FLI-1 gene. This translocation has been implicated in these aggressive and malignant tumors.1–4 Oftentimes, patients present with pain and swelling in the area of the affected bone or joint.5 While there has been some improvement in survival for patients that present with localized tumors, patients presenting with metastases continue to have a poor prognosis.3,6 Current treatment options include surgical resection coupled with chemotherapy and radiation therapy. Recent molecular studies have demonstrated some promise for the development of targeted gene therapy.4 We present a case of a 16-year old boy that presented with leg pain and a mass in his left fibula

Positronium emission from mesoporous silica studied by laser-enhanced time-of-flight spectroscopy

The use of mesoporous silica films for the production and study of positronium (Ps) atoms has become increasingly important in recent years, providing a robust source of free Ps in vacuum that may be used for a wide variety of experiments, including precision spectroscopy and the production of antihydrogen. The ability of mesoporous materials to cool and confine Ps has also been utilized to conduct measurements of Ps–Ps scattering and Ps2 molecule formation, and this approach offers the possibility of making a sufficiently dense and cold Ps ensemble to realize a Ps Bose–Einstein condensate. As a result there is great interest in studying the dynamics of Ps atoms inside such mesoporous structures, and how their morphology affects Ps cooling, diffusion and emission into vacuum. It is now well established that Ps atoms are initially created in the bulk of such materials and are subsequently ejected into the internal voids with energies of the order of 1 eV, whereupon they rapidly cool via hundreds of thousands of wall collisions. This process can lead to thermalisation to the ambient sample temperature, but will be arrested when the Ps deBroglie wavelength approaches the size of the confining mesopores. At this point diffusion through the pore network can only proceed via tunneling, at a much slower rate. An important question then becomes, how long does it take for the Ps atoms to cool and escape into vacuum? In a direct measurement of this process, conducted using laser-enhanced positronium time-of-flight spectroscopy, we show that cooling to the quantum confinement regime in a film with approximately 5 nm diameter pores is nearly complete within 5 ns, and that emission into vacuum takes ~10 ns when the incident positron beam energy is 5 keV. The observed dependence of the Ps emission time on the positron implantation energy supports the idea that quantum confined Ps does not sample all of the available pore volume, but rather is limited to a subset of the mesoporous network

A community based cross sectional study on feasibility of lay interviewers in ascertaining causes of adult deaths by using verbal autopsy in rural Wardha

Background & objectives: 1) To study the causes of adult (15 years and above) deaths using verbal autopsy (VA) and its socio-demographic characteristics. 2) To study the feasibility of use of the lay interviewer to ascertain causes of adult death using verbal autopsy and a simple algorithm. Methods: The present study was done in Wardha district, Maharashtra, India. Taking into account feasibility, out of 23 villages of Primary Health Centre, Anji, 15 villages were chosen having total population of 14,590. Out of 273 estimated adult deaths during the study period, 209 (77%) could be traced by house to house visit and a lay interviewer, interviewed the close caretakers of the deceased. Both lay interviewer and a physician individually derived their diagnosis using verbal autopsy report and a simplified algorithm. The data was entered and analyzed by using Epi_info 6.04. The inter-observer reliability between the lay interviewer and a physician for each possible diagnosis was assessed by using the Kappa statistics. Considering the diagnosis made by a physician as a gold standard, the diagnostic and predictive accuracy for each diagnosis made by the lay interviewer was calculated. Results: The communicable diseases accounted for 52 percent of the adult deaths while non-communicable for 32 percent and injuries for nine percent deaths. The overall agreement between the lay interviewer and a physician for communicable diseases was found to be good (k = 0.65 + 0.06) and for non-communicable diseases it was found to be excellent (k = 0.80 + 0.06). The lay interviewer using VA performed adequately for individual conditions of public health importance like acute febrile illness, diarrheal diseases, tuberculosis and injuries. Interpretation & conclusions: The present study has been successful to demonstrate feasibility of use of the lay interviewer to provide useful information on population-level estimation of broad causes of adult deaths and its socio-demographic characteristics that are reasonably reliable. The study suggests the possible utility of the method for rural India, where the majority of deaths occur at home. Further research work on development of sensitive and specific yet simple algorithms for lay interviewers to ascertain causes of adult deaths is required

Crossover and coexistence of quasiparticle excitations in the fractional quantum Hall regime at nu <= 1/3

New low-lying excitations are observed by inelastic light scattering at filling factors nu=p/(phip+/-1) of the fractional quantum Hall regime with phi=4. Coexisting with these modes throughout the range nuless than or equal to1/3 are phi=2 excitations seen at 1/3. Both phi=2 and phi=4 excitations have distinct behaviors with temperature and filling factor. The abrupt first appearance of the new modes in the low-energy excitation spectrum at nuless than or similar to1/3 suggests a marked change in the quantum ground state on crossing the phi=2-->phi=4 boundary at nu=1/3

The use of happiness research for public policy

Research on happiness tends to follow a "benevolent dictator" approach where politicians pursue people's happiness. This paper takes an antithetic approach based on the insights of public choice theory. First, we inquire how the results of happiness research may be used to improve the choice of institutions. Second, we show that the policy approach matters for the choice of research questions and the kind of knowledge happiness research aims to provide. Third, we emphasize that there is no shortcut to an optimal policy maximizing some happiness indicator or social welfare function since governments have an incentive to manipulate this indicator

Creative use of BIPV materials: barriers and solutions

Inventive use of photovoltaic (PV) materials in architecture can be developed through use of PV in artworks. This is particularly important in increasing the uptake of building-integrated building-integrated photovoltaics (BIPV), by developing novel methods of combining and installing PV materials. Current examples of PV artwork and design are examined, from small to large scale, to assess the current design limitations. The design of two PV artworks is discussed in detail, including an artwork that uses the principle of the luminescent solar concentrator (LSC), to show the way in which design hurdles are discovered and overcome. Challenges range from difficulties in obtaining small quantities of PV materials; the balance between efficiency and artistic effect; through to technical and siting issues that an artist must address when designing a functional PV structure. Methods of overcoming these barriers are explored, including the use of lumogen dyes in encapsulant materials

Selective Production of Rydberg-Stark States of Positronium

Rydberg positronium (Ps) atoms have been prepared in selected Stark states via two-step (1s→2p→nd/ns) optical excitation. Two methods have been used to achieve Stark-state selection: a field ionization filter that transmits the outermost states with positive Stark shifts, and state-selected photoexcitation in a strong electric field. The former is demonstrated for n=17 and 18 while the latter is performed for n=11 in a homogeneous electric field of 1.9  kV/cm. The observed spectral intensities and their dependence on the polarization of the laser radiation are in agreement with calculations that include the perturbations of the intermediate n=2 manifold. Our results pave the way for the generation of Rydberg Ps atoms with large electric dipole moments that are required for the realization of schemes to control their motion using inhomogeneous electric fields, an essential feature of some proposed Ps free-fall measurements requiring focused beams of long-lived atoms