Inverse Characteristics Research Articles

Metabotropic Glutamate Receptor 5 Negative Allosteric Modulators as Novel Tools for in Vivo Investigation

Negative allosteric modulators (NAMs) of metabotropic glutamate receptor subtype 5 (mGluR5) have shown promising results in preclinical models for anxiety and drug abuse. Here we describe a series of aryl-substituted alkynyl analogues of the prototypic mGluR5 NAM 2-methyl-6-(phenylethynyl)pyridine (MPEP, 1). Displacement of [(3)H]1 binding in rat brain membranes showed that several of these novel compounds displayed high affinity binding (K(i) < 10 nM) for mGluR5, with up to a 24-fold increase in affinity over 1. Replacements of the 2-position Me on the pyridyl ring of 1 along with various 3'-CN, 5'-substitutions were generally well tolerated. All of the active analogues in this series had cLogP values in the 2-5 range and displayed inverse agonist characteristics in an ELISA-based assay of G(q)α-mediated IP3 production. Compounds 7i and 7j produced in vivo effects in mouse models of anxiety-like behaviors more potently than 1 or 3-((2-methyl-1,3-thiazol-4-yl)ethynyl)pyridine (MTEP, 2), supporting their utility as in vivo tools.

FEEDFORWARD COMPENSATION TECHNIQUE FOR COMPARATOR DELAY DISPERSION FOR LEVEL-CROSSING ADCS

The accuracy of measuring the crossing moment of a given signal to a specific reference voltage plays a crucial role in determining the bandwidth of the signal that could be converted by a level-crossing ADC. This timing accuracy is mainly determined by delay dispersion of the comparator and the accuracy of the time-to-digital converter (TDC) comprising the level-crossing ADC. With the pico-second resolution TDC, the delay dispersion of the comparator became the bottle nick of the design of a high speed level-crossing ADC. This paper presents a comparator with low delay dispersion for level-crossing analog-to-digital conversion applications. The comparator comprises a technique to compensate the delay dispersion caused by variable input overdrive. The whole circuit is composed of three main blocks, namely, conventional comparator, fixed delay block and variable delay block. The variable delay block is controlled such that it implements the inverse overdrive-delay characteristics of the conventional comparator. Therefore, the overall delay dispersion of the circuit is effectively reduced. Using the proposed technique in a level-crossing ADC would enable the sampling of a signal with 6.15X higher frequency than the case of using a conventional comparator keeping the same SNR.

Acute Cerebrovascular Disease in Pregnancy and Puerperium: Description of Cases from a Mexican Multicenter Registry (RENAMEVASC) (P01.035)

Objective: To describe CVD cases occurring during pregnancy or puerperium in Mexican hospitals. Background Pregnancy and puerperium are physiological conditions associated with a high risk of acute cerebrovascular disease (CVD). Comparative data on the association of pregnancy and puerperium among the different types of acute CVD is sparse. Design/Methods: We analyzed 2000 patients with different types of acute CVD included in a registry conducted in 25 referral hospitals. Research records of cases occurring during pregnancy or puerperium (the first 40 days after delivering) were selected. Results: We identified 45 (2.3%, 95% confidence interval: 1.7% to 3.0%) women with CVD associated with pregnancy or puerperium (mean age 26.3 years, range: 14-39): 20 (44%) in pregnant women and 25 (56%) during puerperium. A total of 26 (58%) cases corresponded to cerebral vein thrombosis (CVT), 10 (22%) to intracerebral hemorrhage (ICH) and 9 (20%) to acute ischemic stroke (AIS). No association with subarachnoid hemorrhage was identified. As compared with puerperium, pregnancy was more common among AIS (56% vs 44%, respectively) and ICH cases (90% vs 10%, respectively), but the inverse characteristic was observed in CVT cases (23% vs 77%, respectively). Ten (22%) patients presented preeclampsia/eclampsia: 7 (70%) in association with ICH, 2 (22%) with AIS and only one (4%) with CVT. The 30-day case fatality rate was 4%, (2 pregnant women: one with ICH and the other with CVT); however, the frequency of women with a modified Rankin scale >2 was 17%; more common among patients with ICH (60%), than in AIS (14%) and CVT (9%) cases. Conclusions: CVT is the main type of acute CVD occurring during pregnancy or puerperium. Preeclampsia/eclampsia was mainly associated with ICH, whereas CVT may be associated with a prothrombotic, non-hypertensive state. Mortality rate is low, but at expense of a significant proportion of disabled young women. Disclosure: Dr. Chiquete has nothing to disclose. Dr. Flores has nothing to disclose. Dr. Florez has nothing to disclose. Dr. Salas has nothing to disclose. Dr. Reyes-Melo has nothing to disclose. Dr. Villarreal-Careaga has nothing to disclose. Dr. Murillo-Bonilla has nothing to disclose. Dr. Leon-Jimenez has nothing to disclose. Dr. Ruiz-Sandoval has nothing to disclose. Dr. Gonzalez-Duarte has nothing to disclose. Dr. Garcia-Ramos has nothing to disclose. Dr. Cantu-Brito has nothing to disclose.

Invited Article: A Multiple-Input and Multiple-Output Long-Term Evolution Precoding Based on Fast Diagonal-Weighted Jacket Matrices

In this article, a fast diagonal-weighted Jacket matrix is proposed to have orthogonal architecture. The successive diagonal-weighted Jacket matrix is developed to reduce the computational load while factorizing the large-order diagonal-weighted Jacket matrices into the low-order sparse matrices with fast algorithms. The proposed diagonal-weighted Jacket matrix is then applied to the precoding multiple-input and multiple-output wireless communications because of its diagonal-weighted framework with element-wise inverse characteristics. Based on the properties of the diagonal-weighted Jacket matrix, the proposed diagonal-weighted Jacket matrix can be used as alternative open-loop cyclic delay diversity precoding, which has recently become part of the cellular communications systems. Performance of the diagonal-weighted Jacket matrix-based precoding system is verified for orthogonal space-time block code multiple-input and multiple-output long-term evolution systems.

Design and Implementation of O/C relay using Microprocessor

This work presents the design and implementation of a versatile digital overcurrent (O/C) relay using a single microprocessor. The relay is implemented by a combination of a look-up table and a counter. The software development and hardware testing are done using a microcomputer module based on a 8-bit microprocessor. The digital processing of measured currents enables a separate setting of operating values selection of all types of inverse or constant time characteristics overcurrent protection. This protection provides reasonably fast tripping, even at terminal close to the power source were the most serve faults can occur excluding the transient condition. So this method has an excellent compromise between accuracy hardware and speed.

Identification for Polynomial Wiener Model Using Improved Back Propagation Method

A new method is introduced for the identification of nonlinear dynamic system described by Wiener model, which consists of a linear dynamic block followed by a static non-linearity. Firstly, it is assumed that static non-linear part is invertible and its inverse characteristics can be expressed or approximated by a polynomial of known orders. Secondly, based on these assumptions, a novel neural network structure is designed, the weights in which are corresponding with the parameters of polynomial Wiener model. Finally, to solve the problem of non-convergence of conventional back propagation iterative, the improved one is derived, through which the non-linear and linear dynamic part can be optimized and the coefficients of the polynomial Wiener model are gotten with a higher convergence rate. A numerical example is included to show the effectiveness and the practical feasibility of the presented approach.

Rapid microwave synthesis of Pb5(VO4)3X (X = F, Cl, Br and I) vanadinite apatites for the immobilisation of halide radioisotopes.

ABSTRACTMicrowave dielectric heating was utilized to synthesize potential host phases for halide radioisotopes. Synthesis of Pb5(VO4)3I was successfully achieved, without the use of a sealed container, using a modified domestic microwave oven (DMO) operating at 2.45 GHz. Rapid synthesis of Pb5(VO4)3X (X = F, Cl, Br) was also achieved using a commercially available microwave muffle furnace, also operating at 2.45 GHz. The combination of rapid heating rate and inverse temperature profile characteristic of microwave heating was found to promote formation of the target phases whilst retarding the volatilization of the halide species. Pb5(VO4)3I ceramic bodies produced in the DMO exhibited a heterogeneous zoned microstructure, whereas Pb5(VO4)3X phases with X = F, Cl, and Br fabricated in the microwave muffle furnace were dimensionally uniform suggesting this could be a promising route to fabricating single phase, dense halide containing ceramics.

Adaptive Digital Predistortion with Iterative Noise Cancelation for Power Amplifier Linearization

In this paper, we propose a power amplifier linearization technique combined with iterative noise cancelation. This method alleviates the effect of added noises which prevents the predistorter (PD) from estimating the exact characteristics of the power amplifier (PA). To iteratively cancel the noise added in the feedback signal, the output signal of the power amplifier without noise is reconstructed by applying the inverse characteristics of the PD to the predistorted signals. The noise can be revealed by subtracting the reconstructed signals from the feedback signals. Simulation results based on the mean-square error (MSE) and power spectral density (PSD) criteria are presented to evaluate PD performance. The results show that the iterative noise cancelation significantly enhances the MSE performance, which leads to an improvement of the out-of-band power suppression. The performance of the proposed technique is verified by computer simulation and hardware test results.

Climatological Characteristics of Arctic and Antarctic Surface-Based Inversions

Surface-based inversions (SBIs) are frequent features of the Arctic and Antarctic atmospheric boundary layer. They influence vertical mixing of energy, moisture and pollutants, cloud formation, and surface ozone destruction. Their climatic variability is related to that of sea ice and planetary albedo, important factors in climate feedback mechanisms. However, climatological polar SBI properties have not been fully characterized nor have climate model simulations of SBIs been compared comprehensively to observations. Using 20 years of twice-daily observations from 39 Arctic and 6 Antarctic radiosonde stations, this study examines the spatial and temporal variability of three SBI characteristic—frequency of occurrence, depth (from the surface to the inversion top), and intensity (temperature difference over the SBI depth)—and relationships among them. In both polar regions, SBIs are more frequent, deeper, and stronger in winter and autumn than in summer and spring. In the Arctic, these tendencies increase from the Norwegian Sea eastward toward the East Siberian Sea, associated both with (seasonal and diurnal) variations in solar elevation angle at the standard radiosonde observation times and with differences between continental and maritime climates. Two state-of-the-art climate models and one reanalysis dataset show similar seasonal patterns and spatial distributions of SBI properties as the radiosonde observations, but with biases in their magnitudes that differ among the models and that are smaller in winter and autumn than in spring and summer. SBI frequency, depth, and intensity are positively correlated, both spatially and temporally, and all three are anticorrelated with surface temperature.

Auto-calibration Based Control and Its Application to a Kind of Electrohydraulic Poppet Valves

Abstract This paper describes a novel learning/adaptive state trajectory control method and its application to electronic hydraulic pressure control. The control algorithm presented herein learns the inverse input-state mapping of the plant at the same time this map is employed in the feedforward loop to force the state of the plant to asymptotically converge to a prescribed state trajectory. The algorithm accomplishes this task without requiring prior exact information about the state transition map of the plant. The novel controller is applied to an electrohydraulic poppet valve with the objective of tracking a desired supply pressure signal. In this application, the controller learns the inverse conductance characteristics of the valve. The supply pressure tracking performance subject to the proposed controller is validated through experimental data.

Characteristics of water-vapour inversions observed over the Arctic by Atmospheric Infrared Sounder (AIRS) and radiosondes

Abstract. An accurate characterization of the vertical structure of the Arctic atmosphere is useful in climate change and attribution studies as well as for the climate modelling community to improve projections of future climate over this highly sensitive region. Here, we investigate one of the dominant features of the vertical structure of the Arctic atmosphere, i.e. water-vapour inversions, using eight years of Atmospheric Infrared Sounder data (2002–2010) and radiosounding profiles released from the two Arctic locations (North Slope of Alaska at Barrow and during SHEBA). We quantify the characteristics of clear-sky water vapour inversions in terms of their frequency of occurrence, strength and height covering the entire Arctic for the first time. We found that the frequency of occurrence of water-vapour inversions is highest during winter and lowest during summer. The inversion strength is, however, higher during summer. The observed peaks in the median inversion-layer heights are higher during the winter half of the year, at around 850 hPa over most of the Arctic Ocean, Siberia and the Canadian Archipelago, while being around 925 hPa during most of the summer half of the year over the Arctic Ocean. The radiosounding profiles agree with the frequency, location and strength of water-vapour inversions in the Pacific sector of the Arctic. In addition, the radiosoundings indicate that multiple inversions are the norm with relatively few cases without inversions. The amount of precipitable water within the water-vapour inversion structures is estimated and we find a distinct, two-mode contribution to the total column precipitable water. These results suggest that water-vapour inversions are a significant source to the column thermodynamics, especially during the colder winter and spring seasons. We argue that these inversions are a robust metric to test the reproducibility of thermodynamics within climate models. An accurate statistical representation of water-vapour inversions in models would mean that the large-scale coupling of moisture transport, precipitation, temperature and water-vapour vertical structure and radiation are essentially captured well in such models.

Challenges in estimating trends in Arctic surface-based inversions from radiosonde data

[1] Because of potential connections between changes in the characteristics of surface-based inversions (SBIs) and other Arctic climate trends, and because of the availability of radiosonde observations from the 1950s to present, one might seek to investigate Arctic SBI trends using radiosonde data. However, changes in observational methods, particularly those affecting sounding vertical resolution, introduce artificial changes in radiosonde representations of SBIs that degrade trend estimates. SBI intensity and depth data are particularly sensitive to this problem, but frequency of SBI occurrence is more robust. Most previous investigations of Arctic SBI trends have erroneously neglected or dismissed this issue. Based on SBI data from the few Arctic stations with homogeneous records during 1990–2009, most trends are not statistically significant, and no clear patterns of SBI change emerge. Among the significant trends, we find SBI intensity trends are positively associated with SBI depth trends, but negatively correlated with the surface temperature trends.

Changing Temperature Inversion Characteristics in the U.S. Southwest and Relationships to Large-Scale Atmospheric Circulation

AbstractContinental temperature inversions significantly influence air quality, yet little is known about their variability in frequency and intensity with time or sensitivity to dynamical changes with climate. Inversion statistics for six upper-air stations in the American Southwest are derived for the period 1994–2008 from radiosonde data reported by the Global Telecommunication System (GTS) and National Climatic Data Center (NCDC), which use different significant level standards. GTS data indicate that low-level elevated inversions have increased in frequency at four of six sites, consistent with enhanced regional stagnation projected by models. NCDC data, in contrast, show remarkable declines in weak, near-surface inversions through 2001, indicating local surface conditions may counteract atmospheric dynamics in regulating inversion activity and air quality. To further test the sensitivity of inversion activity to climate, associations between wintertime inversion frequency and large-scale circulation are quantified using the self-organizing map technique. Twenty-four representative circulation patterns are derived from North American Regional Reanalysis (NARR) 500-hPa geopotential height fields, and these patterns are correlated with inversion frequency at each site. Inversion activity in Salt Lake City, Utah, and Albuquerque and Santa Teresa, New Mexico, is found to correspond well with large-scale anticyclonic ridging; however, sensitivities to large-scale circulation in Denver, Colorado, and Flagstaff and Tucson, Arizona, are weak. Denver stands out in exhibiting a higher percentage of near-surface inversions in winter than the other southwestern sites. These findings indicate that dynamical changes with climate will not uniformly influence inversions and hence urban air quality conditions in the American Southwest.

Rapid synthesis of Pb 5(VO 4) 3I, for the immobilisation of iodine radioisotopes, by microwave dielectric heating

Rapid synthesis of Pb 5(VO 4) 3I, a potential immobilisation host for iodine radioisotopes, was achieved in an open container by microwave dielectric heating of a mixture of PbO, PbI 2, and V 2O 5 at a power of 800 W for 180 s (at 2.45 GHz). The resulting ceramic bodies exhibited a zoned microstructure, differentiated by inter-granular porosity and phase assemblage, as a consequence of the inverse temperature gradient characteristic of microwave dielectric heating. Liquid PbI 2 within the interior of microwave processed ceramics assisted formation of Pb 5(VO 4) 3I, and reduced inter-granular porosity. In contrast, the exterior of microwave processed ceramics comprised poorly sintered Pb 5(VO 4) 3I with the presence of minor reagent relics. Quantitative microanalysis, electron diffraction and Rietveld analysis, confirmed the synthesis of stoichiometric Pb 5(VO 4) 3I within precision. The crystal structure of Pb 5(VO 4) 3I was found to adopt space group P6 3/m with a = 10.4429(3) Å and c = 7.4865(2) Å.

Effect of saturable index change on all-optical logic operations in a passive vertical cavity semiconductor saturable absorber

Semiconductor multiple quantum wells (QWs) have saturable absorption and saturable refractive index change properties. When it is embedded within a reflective Fabry-Perot cavity, the device shows forward and inverse saturation reflectivity for a radiation at cavity resonance wavelength with input intensity around the impedance matching point. Consideration of non-linear index change increases the extinction of forward saturation characteristics of the device. However its application in logic devices is very limited. Whereas, the inverse characteristics for which a number of logic devices can be proposed is severely affected in its extinction because of the consideration of non-linear index change. Here the authors optimise the parameters of vertical cavity semiconductor saturable absorber for the static and dynamic device performance of all-optical logic operations based on inverse saturation characteristics with both dispersive and absorptive saturation into consideration. The authors obtain an extinction of almost 77.5% with input intensity of the order of saturation intensity of a multiple QWs. The novelty of this work lies in the observation that the saturation of non-linear index of refraction has enormous effect on the characteristics of logic operations, which is not addressed in earlier reports. It is also observed that the detrimental effect of non-linear index saturation can be overcome by proper absorber parameters.

Weather-based Prediction of RSV Outbreaks

Weather-based Prediction of RSV Outbreaks

Variability in surface inversion characteristics over India in winter during the recent decades

The variation in surface inversions during the recent decades over 20 stations in the Indian region is documented. Radiosonde data at 00UTC for the period 1971–2000 has been used to compute the inversion frequency. The depth and strength of the inversions as well as the wind speed through the inversion layer have also been computed. The frequency of inversions at stations north of 20°N is ~20–60% higher than stations located south of 20°N. Moreover, all the stations show frequencies increasing from the 1st to the 3rd decade. Most of the stations show decreasing depth and increasing strength significant at 99% level. With the exception of Nagpur and Hyderabad which show high frequency of very deep inversions increasing from the 1st to the 3rd decade, the decadal variations of inversion depth at most of the other stations show that shallow and moderate inversions occur more frequently than deep or very deep inversions. Decadal variations in inversion strength show weak inversion frequencies decreasing from the 1st to the 3rd decade while moderate/strong inversions occur more frequently at most stations. Frequencies of very strong inversions are low or are absent. Wind speeds are either weak or moderate with frequencies increasing from the 1st to the 3rd decade. Low frequency of strong winds and negligible frequency of very strong winds are observed.

Reproduction Apparatus And Reproduction System

A reproduction apparatus comprises an inverse characteristics converting section that converts the acoustic characteristics of an acoustic space into inverse characteristics thereof, a reproducing section that reproduces music data, an acoustic characteristics output section that outputs acoustic characteristics different from the acoustic characteristics of the acoustic space, an adjusting section that adjusts the music data reproduced by the reproduction section on the basis of the inverse acoustic characteristics of the acoustic space converted by the inverse characteristics conversion section and the acoustic characteristics output from the acoustic characteristics output section and an output section that outputs the music data adjusted by the adjustment section to the acoustic space.

Characteristics of Temperature and Humidity Inversions and Low-Level Jets over Svalbard Fjords in Spring

Air temperature and specific humidity inversions and low-level jets were studied over two Svalbard fjords, Isfjorden and Kongsfjorden, applying three tethersonde systems. Tethersonde operation practices notably affected observations on inversion and jet properties. The inversion strength and depth were strongly affected by weather conditions at the 850 hPa level. Strong inversions were deep with a highly elevated base, and the strongest ones occurred in warm air mass. Unexpectedly, downward longwave radiation measured at the sounding site did not correlate with the inversion properties. Temperature inversions had lower base and top heights than humidity inversions, the former due to surface cooling and the latter due to adiabatic cooling with height. Most low-level jets were related to katabatic winds. Over the ice-covered Kongsfjorden, jets were lifted above a cold-air pool on the fjord; the jet core was located highest when the snow surface was coldest. At the ice-free Isfjorden, jets were located lower.

Curvature driven diffusion coupled with shock for image enhancement/reconstruction

Curvature driven diffusion is widely used for image denoising and inpainting. Among the curvature driven diffusion techniques Gauss Curvature Driven Diffusion (GCDD) became a prominent image denoising method due to its capability to retain some important structures with non zero curvatures, like curved edges, corners etc. Unlike many other non-linear diffusion techniques, the curvature driven diffusion hardly has any inverse diffusion characteristics. In this work we propose to introduce a shock term along with the GCDD term to enhance the edges while smoothing-out the noise. This technique will preserve some important structures and enhance them while denoising the image. The experiments clearly demonstrates the efficiency of the method.