Chirp filtering in the fractional Fourier Domain

Cataloged from PDF version of article.In the Wigner domain of a one-dimensional function, a certain chirp term represents a rotated line delta function. On the other hand, a fractional Fourier transform (FRT) can be associated with a rotation of the Wigner-distribution function by an angle connected with the FRT order. Thus with the FRT tool a chirp and a delta function can be transformed one into the other. Taking the chirp as additive noise, the FRT is used for filtering the line delta function in the appropriate fractional Fourier domain. Experimental filtering results for a Gaussian input function, which is modulated by an additive chirp noise, are shown. Excellent agreement between experiments and computer simulations is achieved

Anamorphic Fractional Fourier Transforming--Optical Implementation and Applications

Cataloged from PDF version of article.An additional degree of freedom is introduced to fractional-Fourier-transform systems by use of anamorphic optics. A different fractional Fourier order along the orthogonal principal directions is performed. A laboratory experimental system shows preliminary results that demonstrate the proposed theory. Applications such as anamorphic fractional correlation and multiplexing in fractional domains are briefly suggested. (C) 1995 Optical Society of Americ

Fractional Fourier Transform- Simulations and experimental results

Cataloged from PDF version of article.Recently two optical interpretations of the fractional Fourier transform operator were introduced. We address implementation issues of the fractional-Fourier-transform operation. We show that the original bulk-optics configuration for performing the fractional-Fourier-transform operation 3J. Opt. Soc. Am. A 10, 2181 1199324 provides a scaled output using a fixed lens. For obtaining a non-scaled output, an asymmetrical setup is suggested and tested. For comparison, computer simulations were performed. A good agreement between computer simulations and experimental results was obtained

A computational analysis of lower bounds for big bucket production planning problems

In this paper, we analyze a variety of approaches to obtain lower bounds for multi-level production planning problems with big bucket capacities, i.e., problems in which multiple items compete for the same resources. We give an extensive survey of both known and new methods, and also establish relationships between some of these methods that, to our knowledge, have not been presented before. As will be highlighted, understanding the substructures of difficult problems provide crucial insights on why these problems are hard to solve, and this is addressed by a thorough analysis in the paper. We conclude with computational results on a variety of widely used test sets, and a discussion of future research

Electrophysiological Evidence of Attentional Biases in Social Anxiety Disorder

Background: Previous studies investigating attentional biases in social anxiety disorder (SAD) have yielded mixed results. Recent event-related potential (ERP) studies using the dot-probe paradigm in non-anxious participants have shown that the P1 component is sensitive to visuospatial attention towards emotional faces. We used a dot-probe task in conjunction with high-density ERPs and source localization to investigate attentional biases in SAD. Method: Twelve SAD and 15 control participants performed a modified dot-probe task using angry–neutral and happy–neutral face pairs. The P1 component elicited by face pairs was analyzed to test the hypothesis that SAD participants would display early hypervigilance to threat-related cues. The P1 component to probes replacing angry, happy or neutral faces was used to evaluate whether SAD participants show either sustained hypervigilance or decreased visual processing of threat-related cues at later processing stages. Results: Compared to controls, SAD participants showed relatively (a) potentiated P1 amplitudes and fusiform gyrus (FG) activation to angry–neutral versus happy–neutral face pairs; (b) decreased P1 amplitudes to probes replacing emotional (angry and happy) versus neutral faces; and (c) higher sensitivity (d′) to probes following angry–neutral versus happy–neutral face pairs. SAD participants also showed significantly shorter reaction times (RTs) to probes replacing angry versus happy faces, but no group differences emerged for RT. Conclusions: The results provide electrophysiological support for early hypervigilance to angry faces in SAD with involvement of the FG, and reduced visual processing of emotionally salient locations at later stages of information processing, which might be a manifestation of attentional avoidance.Psycholog

The Nuclear Bulge of the Galaxy. III. Large-Scale Physical Characteristics of Stars and Interstellar Matter

We analyse IRAS and COBE DIRBE data at wavelengths between 2.2 and 240 mu of the central 500pc of the Galaxy and derive the large-scale distribution of stars and interstellar matter in the Nuclear Bulge. Models of the Galactic Disk and Bulge are developed in order to correctly decompose the total surface brightness maps and to apply proper extinction corrections. The Nuclear Bulge appears as a distinct, massive disk-like complex of stars and molecular clouds which is, on a large scale, symmetric with respect to the Galactic Centre. It is distinguished from the Galactic Bulge by its flat disk-like morphology, very high density of stars and molecular gas, and ongoing star formation. The Nuclear Bulge consists of an R^-2 Nuclear Stellar Cluster at the centre, a large Nuclear Stellar Disk with radius 230+-20 pc and scale height 45+-5 pc, and a Nuclear Molecular Disk of same size. Its total stellar mass and luminosity are 1.4+-0.6 10^9 M_sun and 2.5+-1 10^9 L_sun, respectively. The total mass of interstellar hydrogen in the Nuclear Bulge is 2+-0.3 10^7 M_sun. Interstellar matter in the Nuclear Bulge is very clumpy with ~90% of the mass contained in dense and massive molecular clouds with a volume filling factor of only a few per cent. This extreme clumpiness enables the strong interstellar radiation field to penetrate the entire Nuclear Bulge and explains the relatively low average extinction towards the Galactic Centre. In addition, we find 4 10^7 M_sun of cold and dense material located outside the Nuclear Bulge, which gives rise to the observed asymmetry in the distribution of interstellar matter in the Central Molecular Zone.Comment: 28 pages, 22 figures, accepted for publication in A&

Spectral imaging of the Central Molecular Zone in multiple 3-mm molecular lines

We have mapped 20 molecular lines in the Central Molecular Zone (CMZ) around the Galactic Centre, emitting from 85.3 to 93.3 GHz. This work used the 22-m Mopra radio telescope in Australia, equipped with the 8-GHz bandwidth UNSW-MOPS digital filter bank, obtaining \sim 2 km/s spectral and \sim 40 arcsec spatial resolution. The lines measured include emission from the c-C3H2, CH3CCH, HOCO+, SO, H13CN, H13CO+, SO, H13NC, C2H, HNCO, HCN, HCO+, HNC, HC3N, 13CS and N2H+ molecules. The area covered is Galactic longitude -0.7 to 1.8 deg. and latitude -0.3 to 0.2 deg., including the bright dust cores around Sgr A, Sgr B2, Sgr C and G1.6-0.025. We present images from this study and conduct a principal component analysis on the integrated emission from the brightest 8 lines. This is dominated by the first component, showing that the large-scale distribution of all molecules are very similar. We examine the line ratios and optical depths in selected apertures around the bright dust cores, as well as for the complete mapped region of the CMZ. We highlight the behaviour of the bright HCN, HNC and HCO+ line emission, together with that from the 13C isotopologues of these species, and compare the behaviour with that found in extra-galactic sources where the emission is unresolved spatially. We also find that the isotopologue line ratios (e.g. HCO+/H13CO+) rise significantly with increasing red-shifted velocity in some locations. Line luminosities are also calculated and compared to that of CO, as well as to line luminosities determined for external galaxies.Comment: 27 pages, 15 figures, 12 tables, accepted by MNRA

The rise of noncommunicable diseases in Latin America and the Caribbean: challenges for public health policies

The health landscape in Latin America and the Caribbean is changing quickly. The region is undergoing a demographic and epidemiological transition in which health problems are highly concentrated on noncommunicable diseases (NCDs). In light of this, the region faces two main challenges: (1) develop cost-effective policies to prevent NCD risk factors, and (2) increase access to quality healthcare in a scenario in which a large share of the labor force is employed in the informal sector. This paper describes both alternative interventions to expand health insurance coverage and their trade-off with labor informality and moral hazard problems. The paper also focuses on obesity as a case example of an NCD, and emphasizes how lack of knowledge along with self-control problems would lead people to make suboptimal decisions related to food consumption, which may later manifest in obesity problems.Fil: Anauati, Maria Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de San Andrés; ArgentinaFil: Galiani, Sebastian. University of Maryland; Estados UnidosFil: Weinschelbaum, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de San Andrés; Argentin

Healthy Eating as Potential Mediator of Inverse Association between Purpose in Life and Waist Circumference: Emerging Evidence from US and Chilean Cohorts

High sense of purpose in life, a fundamental domain of eudaimonic well-being, has been consistently associated with lower risk for various obesity-related chronic diseases. Although this psychological feature correlates with some health behaviors as potential mediators, its association with healthy eating remains less explored. In addition, studies of these psycho-behavioral and health relationships in the South American population are lacking. This research sought to assess: (1) the cross-sectional association between self-reported purpose in life and overall healthy eating patterns, and (2) healthy food intake as a potential mediator of the inverse relationship between purpose in life and waist circumference. Data collected of 2060 US adults from the MIDUS study (5 ± 12 years, 55% women, mostly white people, and 42.5% obese) and 223 Chilean adults from the CHILEMED study (46.6 ± 9 years, 58.3% women, and 71.3% obese) were used. Anthropometric and sociodemographic variables were collected. Sense of purpose was assessed using the purpose in life subscale of the Ryff’s psychological well-being questionnaire. Diet quality was evaluated using healthy eating or low-fat diet indexes, according to extant food intake data in each cohort. The relationship between these variables was estimated by bivariate and multivariate linear regressions with appropriate adjustments. To establish whether a better diet quality could mediate a link of purpose in life and improved nutritional status (assessed by waist circumference), the association between these three variables was tested by bootstrapping-based mediation analysis. Our results show significant associations of sense of purpose with healthy eating and low-fat dietary patterns in both US and Chilean cohorts, respectively, even after adjusting for sociodemographic variables. According to the mediation analysis, the relationship between sense of purpose and waist circumference, as an indicator of abdominal obesity, appears to be partially mediated by healthier food intake in both samples. In conclusion, our findings suggest a plausible mechanism underlying the favorable impact of this well-being dimension on physical health. Given its protective effects, interventions aimed at increasing purpose in life may facilitate adherence to better dietary patterns, which, in turn, will reduce the risk for obesity-related chronic diseases