On the Hydrogen-Ion Concentration in the Alimentary Canal of Certain Orthopteroid Insects.

The hydrogenion concentration of the foregut, midgut and hindgut in the fifteen species of orthopteroid insects studied ranges from 5.4 to 6.6, 6.0 to 6.8 and 5.4 to 7.0 respectively. The data at our disposal leads us to the following conclusions: -(1) that different groups of insects may differ widely from each other in respect to the pH of the alimentary canal but within a group the range of variation is limited and determined by the group to which the insects belong;(2) that, while insects with different feeding habits may show different midgut pH, the midgut pH of the same insect is not markedly affected by different food given to it, i. e., the midgut pH shows a 'constancy'; (3) that the pH in the foregut and the hindgut may show a variation with change of food; and (4) that there exists a marked degree of correspondence between the pH of the midgut and that of the blood.The hydrogenion concentration of the foregut, midgut and hindgut in the fifteen species of orthopteroid insects studied ranges from 5.4 to 6.6, 6.0 to 6.8 and 5.4 to 7.0 respectively. The data at our disposal leads us to the following conclusions: -(1) that different groups of insects may differ widely from each other in respect to the pH of the alimentary canal but within a group the range of variation is limited and determined by the group to which the insects belong;(2) that, while insects with different feeding habits may show different midgut pH, the midgut pH of the same insect is not markedly affected by different food given to it, i. e., the midgut pH shows a 'constancy'; (3) that the pH in the foregut and the hindgut may show a variation with change of food; and (4) that there exists a marked degree of correspondence between the pH of the midgut and that of the blood

Neural Priming in Human Prefrontal Cortex: Multiple Forms of Learning Reduce Demands on the Prefrontal Executive System.

Past experience is hypothesized to reduce computational demands in PFC by providing bottom-up predictive information that informs subsequent stimulus-action mapping. The present fMRI study measured cortical activity reductions ("neural priming"/"repetition suppression") during repeated stimulus classification to investigate the mechanisms through which learning from the past decreases demands on the prefrontal executive system. Manipulation of learning at three levels of representation-stimulus, decision, and response-revealed dissociable neural priming effects in distinct frontotemporal regions, supporting a multiprocess model of neural priming. Critically, three distinct patterns of neural priming were identified in lateral frontal cortex, indicating that frontal computational demands are reduced by three forms of learning: (a) cortical tuning of stimulus-specific representations, (b) retrieval of learned stimulus-decision mappings, and (c) retrieval of learned stimulus-response mappings. The topographic distribution of these neural priming effects suggests a rostrocaudal organization of executive function in lateral frontal cortex

Polymorphisms in ARMS2/HTRA1 and complement genes and age-related macular degeneration in India: findings from the INDEYE study.

PURPOSE: Association between genetic variants in complement factor H (CFH), factor B (CFB), component 2 (C2), and in the ARMS2/HTRA1 region with age-related macular degeneration (AMD) comes mainly from studies of European ancestry and case-control studies of late-stage disease. We investigated associations of both early and late AMD with these variants in a population-based study of people aged 60 years and older in India. METHODS: Fundus images were graded using the Wisconsin Age-Related Maculopathy Grading System and participants assigned to one of four mutually exclusive stages based on the worse affected eye (0 = no AMD, 1-3 = early AMD, 4 = late AMD). Multinomial logistic regression was used to derive risk ratios (RR) accounting for sampling method and adjusting for age, sex, and study center. RESULTS: Of 3569 participants, 53.2% had no signs of amd, 45.6% had features of early amd, and 1.2% had late amd. CFH (RS1061170), C2 (RS547154), OR CFB (RS438999) was not associated with early or late AMD. In the ARMS2 locus, RS10490924 was associated with both early (adjusted RR 1.22, 95% confidence interval [CI]: 1.13-1.33, P < 0.0001) and late AMD (adjusted RR 1.81, 95% CI: 1.15-2.86; P = 0.01); rs2672598 was associated only with early AMD (adjusted RR 1.12, 95% CI: 1.02-1.23; P = 0.02); rs10490923 was not associated with early or late AMD. CONCLUSIONS: Two variants in ARMS2/HTRA1 were associated with increased risk of early AMD, and for one of these, the increased risk was also evident for late AMD. The study provides new insights into the role of these variants in early stages of AMD in India

Analytic preconditioners for decoupled potential integral equations for wideband analysis of scattering from PEC objects

Many integral equations used to analyze scattering, such as the standard combined field integral equation (CFIE), are not well-conditioned for a wide range of frequencies and multi-scale geometries. There has been significant effort to alleviate this problem. A more recent one is using a set of decoupled potential integral equations (DPIE). These equations have been shown to be robust at low frequencies and immune to topology breakdown. But they mimic the behavior of CFIE at high frequencies. This paper addresses this deficiency. We do so by deriving new Calder\'{o}n-type identities through the Vector Potential Integral Equation (VPIE) and Scalar Potential Integral Equation (SPIE), and constructing novel analytic preconditioners for the vector potential integral equation (VPIE) and scalar potential integral equation (SPIE) constrained to perfect electric conductors (PEC). These new formulations are wide-band well-conditioned and converge rapidly for multi-scale geometries. This is demonstrated though a number of examples that use analytic and piecewise basis sets

Trapping dust particles in the outer regions of protoplanetary disks

In order to explain grain growth to mm sized particles and their retention in outer regions of protoplanetary disks, as it is observed at sub-mm and mm wavelengths, we investigate if strong inhomogeneities in the gas density profiles can slow down excessive radial drift and can help dust particles to grow. We use coagulation/fragmentation and disk-structure models, to simulate the evolution of dust in a bumpy surface density profile which we mimic with a sinusoidal disturbance. For different values of the amplitude and length scale of the bumps, we investigate the ability of this model to produce and retain large particles on million years time scales. In addition, we introduced a comparison between the pressure inhomogeneities considered in this work and the pressure profiles that come from magnetorotational instability. Using the Common Astronomy Software Applications ALMA simulator, we study if there are observational signatures of these pressure inhomogeneities that can be seen with ALMA. We present the favorable conditions to trap dust particles and the corresponding calculations predicting the spectral slope in the mm-wavelength range, to compare with current observations. Finally we present simulated images using different antenna configurations of ALMA at different frequencies, to show that the ring structures will be detectable at the distances of the Taurus Auriga or Ophiucus star forming regions.Comment: Pages 15, Figures 14. Accepted for publication in Astronomy and Astrophysic

Driven Morse Oscillator: Model for Multi-photon Dissociation of Nitrogen Oxide

Within a one-dimensional semi-classical model with a Morse potential the possibility of infrared multi-photon dissociation of vibrationally excited nitrogen oxide was studied. The dissociation thresholds of typical driving forces and couplings were found to be similar, which indicates that the results were robust to variations of the potential and of the definition of dissociation rate. PACS: 42.50.Hz, 33.80.WzComment: old paper, 8 pages 6 eps file

On the shock behaviour and response of Ovis Aries vertebrae

When investigating a biological system during shock loading, it is best practice to isolate different components to fully comprehend each individual part [1,2] before building up the system as a whole. Due to the high acoustic impedance of bone in comparison to other biological tissues [3] the majority of the shock will be transmitted into this medium, and as such can cause large amounts of damage to other parts of the body potentially away from the impact area

Evidence on triggered seismicity associated with the October 20, 1991 Uttarkashi earthquake (Garhwal Himalaya)

Two swarms of small earthquakes occurred on 22-24 October, 1995 and 13-18 September, 1996 about 15 km to the West-South-West (WSW) of the 1991 Uttarkashi earthquake (mb = 6.6) in Himalayas. The later swarm has migrated 5 km to the WSW of the former. Analyses of their seismicity rates, width of apertures and migration rates show that these swarms are triggered by a disturbance caused by the occurrence of the Uttarkashi earthquake thus triggered by this event. The disturbance, having slow propagation, rate represents evidence of creep of the earth material transferring stresses to the WSW direction. Occurrence  of creep (stable-slip) motion is supported by the inferred south-west (SW) orientation of compressive stresses in  Uttarkashi earthquake and presence of the north-west (NW) trending shear zones in the region. Ongoing convergence between India and Tibet would have provided the necessary tectonic forces transverse to the NW-SE trend of the Garhwal Himalayas indicating the future seismic activity of the region