Is a low sacral ratio associated with primary vesicoureteral reflux in children?

Introduction: The association of sacral anomalies with fecal incontinence and lower urinary tract dysfunction is known. The sacral ratio is proposed as a tool for evaluation of sacral development. The aim of this cross-sectional study was to evaluate the prevalence and severity of vesicoureteral reflux in children with a low sacral ratio. Materials and Methods: Six hundred and sixty nine children who were referred to a radiology clinic for a standard (fluoroscopic) VCUG to detect vesicoureteral reflux and other anomalies of the lower urinary tract after an episode of urinary tract infection were included in the study and their sacral ratios were measured. Results: All children were younger than 14 years of age (mean 3.44±3.20). Of 669 children, 593 (88.6%) had normal sacral ratios out of whom 423 (71.3%) did not have VUR and 170 (28.7%) had VUR. Seventy-six (11.3%) children out of 669 cases had low sacral ratios; 49 (64.5%) of them had no VUR and 27 (35.5%) had VUR. There was no significant difference in the prevalence of VUR between children with and without a low sacral ratio (p value=0.217). Also, there was no significant difference or trend between a low sacral ratio and the severity of reflux (Chi2 for trend). Conclusions: Although sacral anomalies may be related to some cases of VUR by producing lower urinary tract dysfunction, the sacral ratio is not associated with VUR

Oil Exports and the Iranian Economy

This paper develops a long run growth model for a major oil exporting economy and derives conditions under which oil revenues are likely to have a lasting impact. This approach contrasts with the standard literature on the "Dutch disease" and the "resource curse", which primarily focus on short run implications of a temporary resource discovery. Under certain regularity conditions and assuming a Cobb Douglas production function, it is shown that (log) oil exports enter the long run output equation with a coefficient equal to the share of capital. The long run theory is tested using a new quarterly data set on the Iranian economy over the period 1979Q1-2006Q4. Building an error correction specification in real output, real money balances, inflation, real exchange rate, oil exports, and foreign real output, the paper finds clear evidence for two long run relations: an output equation as predicted by the theory and a standard real money demand equation with inflation acting as a proxy for the (missing) market interest rate. Real output in the long run is shaped by oil exports through their impact on capital accumulation, and the foreign output as the main channel of technological transfer. The results also show a significant negative long run association between inflation and real GDP, which is suggestive of economic inefficiencies. Once the effects of oil exports are taken into account, the estimates support output growth convergence between Iran and the rest of the world. We also find that the Iranian economy adjusts quite quickly to the shocks in foreign output and oil exports, which could be partly due to the relatively underdeveloped nature of Iran’s financial markets

Non-linear response to electric field in extended Hubbard models

The electric-field response of a one-dimensional ring of interacting fermions, where the interactions are described by the extended Hubbard model, is investigated. By using an accurate real-time propagation scheme based on the Chebyshev expansion of the evolution operator, we uncover various non-linear regimes for a range of interaction parameters that allows modeling of metallic and insulating (either charge density wave or spin density wave insulators) rings. The metallic regime appears at the phase boundary between the two insulating phases and provides the opportunity to describe either weakly or strongly correlated metals. We find that the {\it fidelity susceptibility} of the ground state as a function of magnetic flux piercing the ring provides a very good measure of the short-time response. Even completely different interacting regimes behave in a similar manner at short time-scales as long as the fidelity susceptibility is the same. Depending on the strength of the electric field we find various types of responses: persistent currents in the insulating regime, dissipative regime or damped Bloch-like oscillations with varying frequencies or even irregular in nature. Furthermore, we also consider the dimerization of the ring and describe the response of a correlated band insulator. In this case the distribution of the energy levels is more clustered and the Bloch-like oscillations become even more irregular

Uncertainty aversion in Australian regulation of agricultural gene technology

There is potential for over-provision of environmental harms and under-provision of environmental benefits associated with GM crops. As a result, strong public regulation is needed to ensure that full social values are considered. However, one reason for opposition to GM crops is a lack of public trust in regulatory institutions and science, and the limited opportunities afforded to public-participation and nonscientific concerns. We aim to demonstrate the trade-off between social cost and managing the risks of gene flow arising from environmental release of GM canola in Australia, using the framework of a probabilistic risk assessment and safety-rule decision mechanism.safety-rule, uncertainty, biotechnology regulation, canola, Crop Production/Industries, Institutional and Behavioral Economics, Research and Development/Tech Change/Emerging Technologies, Risk and Uncertainty,

3D Simulation of the Effects of Surface Defects on Field Emitted Electrons

The ev­er-grow­ing de­mand for high­er beam en­er­gies has dra­mat­i­cal­ly in­creased the risk of RF break­down, lim­it­ing the max­i­mum achiev­able ac­cel­er­at­ing gra­di­ent. Field emis­sion is the most fre­quent­ly en­coun­tered RF break­down where it oc­curs at re­gions of lo­cal­ly en­hanced elec­tric field. Elec­trons ac­cel­er­at­ed across the cav­i­ty as they tun­nel through the sur­face in the pres­ence of mi­cro­scop­ic de­fects. Upon Im­pact, most of the ki­net­ic en­er­gy is con­vert­ed into heat and stress. This can in­flict ir­re­versible dam­age to the sur­face, cre­at­ing ad­di­tion­al field emis­sion sites. This work aims to in­ves­ti­gate, through sim­u­la­tion, the physics in­volved dur­ing both emis­sion and im­pact of elec­trons. A newly de­vel­oped 3D field model of an 805 MHz cav­i­ty is gen­er­at­ed by COM­SOL Mul­ti­physics. Elec­tron track­ing is per­formed using a Mat­lab based code, cal­cu­lat­ing the rel­e­vant pa­ram­e­ters need­ed by em­ploy­ing fourth Order Runge Kutta in­te­gra­tion. By study­ing such be­haviours in 3D, it is pos­si­ble to iden­ti­fy how the cav­i­ty sur­face can alter the local RF field and lead to break­down and sub­se­quent dam­ages. The ul­ti­mate aim is to in­tro­duce new sur­face stan­dards to en­sure bet­ter cav­i­ty per­for­mance