AdS (In)stability: Lessons From The Scalar Field

We argued in arXiv:1408.0624 that the quartic scalar field in AdS has features that could be instructive for answering the gravitational stability question of AdS. Indeed, the conserved charges identified there have recently been observed in the full gravity theory as well. In this paper, we continue our investigation of the scalar field in AdS and provide evidence that in the Two-Time Formalism (TTF), even for initial conditions that are far from quasi-periodicity, the energy in the higher modes at late times is exponentially suppressed in the mode number. Based on this and some related observations, we argue that there is no thermalization in the scalar TTF model within time-scales that go as $\sim 1/\epsilon^2$, where $\epsilon$ measures the initial amplitude (with only low-lying modes excited). It is tempting to speculate that the result holds also for AdS collapse.Comment: 10 pages, 4 figure

Distributed development and product line decisions

Distributed product development is becoming increasingly prevalent in a number of industries. We study how the global distribution of product development impacts the profit-maximizing product line that a firm offers. Specifically, we formulate a model to understand the linkage between cost arbitrage as a driver of distributed development and consequent market implications such as customer perceived quality loss to remotely developed products. Analysis of the model reveals that a firm should expand the product line for a development-intensive good only at intermediate values of cost advantage and quality loss. We modify the base model to include development capacity constraints as a driver of distributed development and find that the results are robust to this change. Our analysis affirms the need for product managers to incorporate the implications of distributed development in making their product line design decision

Potential of Pandanus odoratissimus as a CNS depressant in Swiss albino mice

In this study, several neuropharmacological effects of methanolic leaf extract of Pandanus odoratissimus (PO) (family; Pandanaceae) were studied in albino mice using various experimental models. The effect of PO on the CNS was studied by using different neuropharmacological paradigms including spontaneous motor activity, rota-rod performance and potentiation of Pentobarbital sodium sleeping time in albino mice. Preliminary phytochemical evaluation and acute toxicity studies were also carried out where LD50 >;2000 mg/kg was considered non-toxic through acute exposure in rats by the oral route. The methanolic leaf extract (50,100 and 200 mg/kg i. p.) produced a reduction in spontaneous motor activity, motor coordination and prolonged Pentobarbital sodium sleeping time. Preliminary qualitative chemical studies indicated the presence of steroids, saponins, terpinoids, glycosides, tannins, flavonoids and phenolics in the extract. These observations suggest that the leaf of Pandanus odoratissimus contains some active principles which possess potential CNS-depressant actionEstudaram-se alguns efeitos neurofarmacológicos do extrato metanólico de Pandanus odoratissimus (PO) (família Pandanaceae) em camundongos albinos, usando vários modelos experimentais. O efeito do PO no SNC foi estudado por meio de diferentes paradigmas neurofarmacológicos, como atividade motora espontânea, desempenho na haste rotatória e a potenciação do tempo de sono em camundongos albinos pelo pentobarbital sódico. A avaliação fitoquímica preliminar e os estudos de toxicidade aguda foram realizados e a DL50 >;2000 mg/kg é considerada não tóxica, por meio da exposição aguda, por via oral, em ratos. O extrato metanólico de folha (50,100 e 200 mg/kg i. p.) produziu redução da atividade motora espontânea, da coordenação motora e tempo prolongado de sono pelo pentobarbital sódico. Estudos químicos qualitativos preliminares indicaram a presença de esteróide, saponinas, terpenóides, glicosídios, taninos, flavonóides e fenólicos no extrato. As observações sugerem que a folha de Pandanus odoratissimus contém alguns princípios ativos com atividade potencial como depressores do SNC

Digitization and analysis of capnography using image processing technique

The study of carbon dioxide expiration is called capnometry. The graphical representation of capnometry is called capnography. There is a growing interest in the usage of capnography as the usage has expanded toward the study of metabolism, circulation, lung perfusion and diffusion, quality of spontaneous respiration, and patency of airways outside of its typical usage in the anesthetic and emergency medicine field. The parameters of the capnograph could be classified as carbon dioxide (CO2) concentration and time points and coordinates, slopes angle, volumetric studies, and functional transformation of wave data. Up to date, there is no gold standard device for the calculation of the capnographic parameters. Capnography digitization using the image processing technique could serve as an option. From the algorithm we developed, eight identical breath waves were tested by four investigators. The values of the parameters chosen showed no significant difference between investigators. Although there were no significant differences between any of the parameters tested, there were a few related parameters that were not calculable. Further testing after refinement of the algorithm could be done. As more capnographic parameters are being derived and rediscovered by clinicians and researchers alike for both lung and non-lung-related diseases, there is a dire need for data analysis and interpretation. Although the proposed algorithm still needs minor refinements and further large-scale testing, we proposed that the digitization of the capnograph via image processing technique could serve as an intellectual option as it is fast, convenient, easy to use, and efficient

Acute fluid shifts influence the assessment of serum vitamin D status in critically ill patients

Recent reports have highlighted the prevalence of vitamin D deficiency and suggested an association with excess mortality in critically ill patients. Serum vitamin D concentrations in these studies were measured following resuscitation. It is unclear whether aggressive fluid resuscitation independently influences serum vitamin D.Nineteen patients undergoing cardiopulmonary bypass were studied. Serum 25(OH)D(3), 1α,25(OH)(2)D(3), parathyroid hormone, C-reactive protein (CRP), and ionised calcium were measured at five defined timepoints: T1 - baseline, T2 - 5 minutes after onset of cardiopulmonary bypass (CPB) (time of maximal fluid effect), T3 - on return to the intensive care unit, T4 - 24 hrs after surgery and T5 - 5 days after surgery. Linear mixed models were used to compare measures at T2-T5 with baseline measures.Acute fluid loading resulted in a 35% reduction in 25(OH)D(3) (59 ± 16 to 38 ± 14 nmol/L, P < 0.0001) and a 45% reduction in 1α,25(OH)(2)D(3) (99 ± 40 to 54 ± 22 pmol/L P < 0.0001) and i(Ca) (P < 0.01), with elevation in parathyroid hormone (P < 0.0001). Serum 25(OH)D(3) returned to baseline only at T5 while 1α,25(OH)(2)D(3) demonstrated an overshoot above baseline at T5 (P < 0.0001). There was a delayed rise in CRP at T4 and T5; this was not associated with a reduction in vitamin D levels at these time points.Hemodilution significantly lowers serum 25(OH)D(3) and 1α,25(OH)(2)D(3), which may take up to 24 hours to resolve. Moreover, delayed overshoot of 1α,25(OH)(2)D(3) needs consideration. We urge caution in interpreting serum vitamin D in critically ill patients in the context of major resuscitation, and would advocate repeating the measurement once the effects of the resuscitation have abated

Fabrication of transmissive dielectric elastomer actuator driven tunable optical gratings with improved tunability

We present an electrically actuated tunable optical grating based on dielectric elastomer actuators. A simple fabrication protocol is presented, which integrates the grating with the actuating mechanism both made of soft elastomers, improving the tunability of the grating. The device is designed to be operated in the transmission mode. It exhibits a continuous period tunability of 34.4% at an actuation voltage of 5.5 kV, which is an improvement over reported tunable optical gratings