Design and Analysis of Mirror Modules for IXO and Beyond

Advancements in X-ray astronomy demand thin, light, and closely packed thin optics which lend themselves to segmentation of the annular mirrors and, in turn, a modular approach to the mirror design. The functionality requirements of such a mirror module are well understood. A baseline modular concept for the proposed International X-Ray Observatory (IXO) Flight Mirror Assembly (FMA) consisting of 14,000 glass mirror segments divided into 60 modules was developed and extensively analyzed. Through this development, our understanding of module loads, mirror stress, thermal performance, and gravity distortion have greatly progressed. The latest progress in each of these areas is discussed herein. Gravity distortion during horizontal X-ray testing and on-orbit thermal performance have proved especially difficult design challenges. In light of these challenges, fundamental trades in modular X-ray mirror design have been performed. Future directions in module X-ray mirror design are explored including the development of a 1.8 m diameter FMA utilizing smaller mirror modules. The effect of module size on mirror stress, module self-weight distortion, thermal control, and range of segment sizes required is explored with advantages demonstrated from smaller module size in most cases

799-2 Left Ventricular (LV) and Myocyte Electrophysiology with the Development of Dilated Cardiomyopathy (DCM); Effects of Angiotensin II Receptor (AT1 AT-II) Blockade

Ventricular arrhythmias are a significant cause of morbidity and mortality with DCM, and AT1 AT-II receptor activation has been implicated to play a role in arrhythmogenesis. However, the effects of AT1, AT-II receptor activation on changes in LV function and myocyte electrophysiology during the progression of DCM remain unexplored. Accordingly, this study measured weekly changes in LV function (ejection fraction, LVEF; peak systolic wall stress, LVWS) and surface electrocardiography (R-R interval, QRS duration, QTc interval), and myocyte action potentials (resting membrane, RM; upstroke velocity, Vmax; duration at 90% repolarization, APD90) at terminal study in 3 groups of dogs (n=6/group): DCM, chronic pace (216 bpm, 4 weeks); DCM/AT-BLOCK, chronic pace and treatment with a specific non-peptide AT1 AT-II antagonist (SR 47436 (BMS 186295); 30mg/kg BID); and control (CON). All measurements were made with the pacemaker deactivated.LVEF (%)LVWS (g/cm2)R-R (ms).QRS (ms).QTc (ms)Week 2:CON68.7±3.2133±14646±9958.4±1.3291±13DCM40.9±4.1*184±16*519±4060.7±1.9316±9DCM/AT-Block44.1±3.7*138±10+540±566.32±1.2*325±9Week4:CON73.1±2.4127±10629±4557.6±1.4314±9DCM35.2±3.5*223±16*505±41*62.0±1.9313±9DCM/AT-Block35.2±2.7*160±13*+578±4865.7±1.5*296±6*p<0.05 vs CON+p<0.05 vs DCMWith DCM, RM (-71±l* vs -78±1mV) and APD90 (257±9* vs 226±7ms) increased, and Vmax decreased (121±5* vs 158±9V/s) compared to CON. In contrast, with AT-BLOCK, RM became more negative (-76±1+mV), APD90 was reduced (183±14*+) and Vmax increased (165±13+).SummaryAT1 AT-II receptor blockade during the progression of DCM caused significant changes in LV myocardial conduction and myocyte action potentials. These results suggest that AT1 AT-II receptor activation plays a contributory role toward the changes in LV electrophysiology with DCM

Slow roll in simple non-canonical inflation

We consider inflation using a class of non-canonical Lagrangians for which the modification to the kinetic term depends on the field, but not its derivatives. We generalize the standard Hubble slow roll expansion to the non-canonical case and derive expressions for observables in terms of the generalized slow roll parameters. We apply the general results to the illustrative case of ``Slinky'' inflation, which has a simple, exactly solvable, non-canonical representation. However, when transformed into a canonical basis, Slinky inflation consists of a field oscillating on a multi-valued potential. We calculate the power spectrum of curvature perturbations for Slinky inflation directly in the non-canonical basis, and show that the spectrum is approximately a power law on large scales, with a ``blue'' power spectrum. On small scales, the power spectrum exhibits strong oscillatory behavior. This is an example of a model in which the widely used solution of Garriga and Mukhanov gives the wrong answer for the power spectrum.Comment: 9 pages, LaTeX, four figures. (V2: minor changes to text. Version submitted to JCAP.

Inflationary potentials in DBI models

We study DBI inflation based upon a general model characterized by a power-law flow parameter $\epsilon(\phi)\propto\phi^{\alpha}$ and speed of sound $c_s(\phi)\propto\phi^{\beta}$, where $\alpha$ and $\beta$ are constants. We show that in the slow-roll limit this general model gives rise to distinct inflationary classes according to the relation between $\alpha$ and $\beta$ and to the time evolution of the inflaton field, each one corresponding to a specific potential; in particular, we find that the well-known canonical polynomial (large- and small-field), hybrid and exponential potentials also arise in this non-canonical model. We find that these non-canonical classes have the same physical features as their canonical analogs, except for the fact that the inflaton field evolves with varying speed of sound; also, we show that a broad class of canonical and D-brane inflation models are particular cases of this general non-canonical model. Next, we compare the predictions of large-field polynomial models with the current observational data, showing that models with low speed of sound have red-tilted scalar spectrum with low tensor-to-scalar ratio, in good agreement with the observed values. These models also show a correlation between large non-gaussianity with low tensor amplitudes, which is a distinct signature of DBI inflation with large-field polynomial potentials.Comment: Minor changes, reference added. Version submitted to JCA

Tensors, non-Gaussianities, and the future of potential reconstruction

We present projections for reconstruction of the inflationary potential expected from ESA's upcoming Planck Surveyor CMB mission. We focus on the effects that tensor perturbations and the presence of non-Gaussianities have on reconstruction efforts in the context of non-canonical inflation models. We consider potential constraints for different combinations of detection/null-detection of tensors and non-Gaussianities. We perform Markov Chain Monte Carlo and flow analyses on a simulated Planck-precision data set to obtain constraints. We find that a failure to detect non-Gaussianities precludes a successful inversion of the primordial power spectrum, greatly affecting uncertainties, even in the presence of a tensor detection. In the absence of a tensor detection, while unable to determine the energy scale of inflation, an observable level of non-Gaussianities provides correlations between the errors of the potential parameters, suggesting that constraints might be improved for suitable combinations of parameters. Constraints are optimized for a positive detection of both tensors and non-Gaussianities.Comment: 12 pages, 5 figures, LaTeX; V2: version submitted to JCA

Impact of operative indication and surgical complexity on outcomes after thoracic endovascular aortic repair at National Surgical Quality Improvement Program Centers

IntroductionThoracic endovascular aortic repair (TEVAR) devices are increasingly being utilized to treat aortic pathologies outside of the original Food & Drug Administration (FDA) approval for nonruptured descending thoracic aorta aneurysms (DTAs). The objective of this study was to evaluate the outcomes of patients undergoing TEVAR, elucidating the role of surgical and pathologic variables on morbidity and mortality.MethodsNational Surgical Quality Improvement Program (NSQIP) data were reviewed for all patients undergoing endovascular thoracic aorta repair from 2005 to 2007. The patients' operative indication and surgical complexity were used to divide them into study and control populations. Comorbid profiles were assessed utilizing a modified Charlson Comorbidity Index (CCI). Thirty-day occurrences of mortality and serious adverse events (SAEs) were used as study endpoints. Univariate and multivariate models were created using demographic and clinical variables to assess for significant differences in endpoints (P ≤ .05).ResultsA total of 440 patients undergoing TEVAR were identified. When evaluating patients based on operative indication, the ruptured population had increased mortality and SAE rates compared to the nonruptured DTA population (22.6% vs 6.2%;P < .01 and 35.5% vs 9.1%;P < .01, respectively). Further analysis by surgical complexity revealed increased mortality and SAE rates when comparing the brachiocephalic aortic debranching population to the noncovered left subclavian artery population (23.1% vs 6.5%; P = .02 and 30.8% vs 9.1%; P < .01, respectively). Multivariate analysis demonstrated that operative indication was not a correlate of mortality or SAEs (odds ratio [OR], 0.95; P = .92 and OR, 1.42; P = .39, respectively); however, brachiocephalic aortic debranching exhibited a deleterious effect on mortality (OR, 8.75; P < .01) and SAE rate (OR, 6.67; P = .01).ConclusionThe operative indication for a TEVAR procedure was not found to be a predictor of poor patient outcome. Surgical complexity, specifically the need for brachiocephalic aortic debranching and aortoiliac conduit, was shown to influence the occurrence of SAEs in a multivariate model. Comparative data, such as these, illustrate real-world outcomes of patients undergoing TEVAR outside of the original FDA-approved indications. This information is of paramount importance to various stakeholders, including third-party payers, the device industry, regulatory agencies, surgeons, and their patients

Evolution of Integrated Crop-Livestock Production Systems

Many factors contribute to changes in the crop-livestock systems, but no logical end-point in the evolution process exists. While benefits of integrated crop-livestock systems over specialised crop and livestock systems are well documented, there has been a move to specialised crop and livestock production. Sustainability issues (manure nutrient concentration, soil quality maintenance, salinity, herbicide resistance, economic instability) have created a renewed interest in integrated crop-livestock systems. Farmer adaptability is as an important link in the evolution between ‘states of integration’

Evolution of Integrated Crop-Livestock Production Systems

Key points 1. Many factors contribute to changes in the crop-livestock systems, but no logical end-point in the evolution process exists. 2. While benefits of integrated crop-livestock systems over specialised crop and livestock systems are well documented, there has been a move to specialised crop and livestock production. 3. Sustainability issues (manure nutrient concentration, soil quality maintenance, salinity, herbicide resistance, economic instability) have created a renewed interest in integrated crop-livestock systems. 4. Farmer adaptability is as an important link in the evolution between ‘states of integration’