On the spatial distribution of dark matter halos

We study the spatial distribution of dark matter halos in the Universe in terms of their number density contrast, related to the underlying dark matter fluctuation via a non-local and non-linear bias random field. The description of the matter dynamics is simplified by adopting the `truncated' Zel'dovich approximation to obtain both analytical results and simulated maps. The halo number density field in our maps and its probability distribution reproduce with excellent accuracy those of halos in a high-resolution N-body simulation with the same initial conditions. Our non-linear and non-local bias prescription matches the N-body halo distribution better than any Eulerian linear and local bias.Comment: 4 pages, LaTeX (uses emulateapj; included psfig.tex), 3 figures, 1 table. Shortened version, matching the size requirements of ApJ Letters. Accepted for publicatio

Imported African histoplasmosis by Histoplasma capsulatum var. duboisii in an HIV-2 infected patient

Objectives: African histoplasmosis caused by the fungus Histoplasma capsulatum var. duboisii, is a rare endemic mycosis occuring in western and central regions of sub-Saharian Africa. For unknown reasons, although HIV infection and H. capsulatum var. duboisii coexist in Africa, this coinfection remains rare. In Europe, diagnosed cases of African histoplasmosis are all imported. We describe a case of African histoplasmosis on a Portuguese war veteran co-infected with HIV-2 who fought in Guiné-Bissau in 1963-65 and Angola in 1972. Methods: We report a case of a 76-year-old man, diagnosed with HIV-2 infection in the previous year (under combined antiretroviral therapy) presenting an ulcerated skin lesion on the right tight (image 1), just above the knee. He was diagnosed pulmonary tuberculosis the year before and was finishing one year treatment. The solitary skin lesion begun as a small non-pruriginous eritematous papule, evolving in 6 month to a painless 3-4cm ulcer with raised borders surrounded by a hiperpigmented halo. There were no adenopathies or bone lesions. Respiratory samples and blood cultures were systematically negative for Histoplasma capsulatum. He was treated with IV liposomal Amphotericin-B for one month, followed by oral itraconazol (now on the first month), with a favourable clinical outcome. Results: Histopathology of skin biopsy revealed a superficial ulceration with underlying granulomatous infiltrate with many giant cells, where numerous round mononucleated yeasts measuring 7-8µm were evident and highlighted with PAS and Grocott stain (image 2, left side). Skin biopsy was observed on a wet mount with KOH and revealed numerous round yeasts that were also seen on Gram stain, measuring 7-8µm. Culture of skin biopsy on two Sabouraud dextrose agar (with and without cicloheximide) showed growth of a filamentous fungus compatible with Histoplasma capsulatum (image 2, right side), with large thick-walled spherical macroconidia with finger-like projections (tuberculate conidia) that arise from short conidiophores, and small oval microconidia arising on short stalks from undifferentiated hyphae. Reversion to the yeast fase has not been succeed yet. Identification was further confirmed by sequencing of genomic DNA fragments using the universal fungal primers ITS1 and ITS4. The sequences obtained were compared with sequences deposited in the GenBank and the result was: Histoplasma capsulatum var. duboisii (99% homology). Conclusion: With banalization of business or leisure trips, endemic mycosis are becoming frequently diagnosed in countries outside their natural geographic endemic areas and only a high index of suspicion makes the diagnosis possible. Apart from trips, nowadays in Portugal 4% of the resident population is immigrant, mostly from Brasil (25.5%) but also from Angola and Guiné-Bissau (9.2%), being the former an endemic country of American histoplasmosis and the later of both American and African histoplasmosis. We consider histoplasmosis a probable underdiagnosed disease that should be suspected mainly in immunodeficient HIV positive individuals with a past history of travel or residence in an endemic area

Absolute Hyperglycemia versus Stress Hyperglycemia Ratio for the Prognosis of Hospitalized Patients with COVID-19 in the First Months of the Pandemic: A Retrospective Study

Diabetes is a risk factor for greater severity of coronavirus disease 2019 (COVID-19). The stress hyperglycemia ratio (SHR) is an independent predictor of critical illness, and it is reported to have a stronger association than absolute hyperglycemia. The aim of this study was to assess the relationship of absolute hyperglycemia and SHR with the severity of COVID-19, since there are no studies investigating SHR in patients with COVID-19. We conducted a retrospective observational study on hospitalized patients with COVID-19 in the first months of the pandemic, regarding absolute hyperglycemia, SHR, and severity outcomes. Of the 374 patients, 28.1% had a previous diagnosis of type 2 diabetes. Absolute hyperglycemia (64.8% versus 22.7%; p < 0.01) and SHR [1.1 (IQR 0.9-1.3) versus 1.0 (IQR 0.9-1.2); p < 0.001] showed a statistically significant association with previous diabetes. Absolute hyperglycemia showed a significant association with clinical severity of COVID-19 (79.0% versus 62.7%; p < 0.001), need for oxygen therapy (74.8% versus 54.4%; p < 0.001), invasive mechanical ventilation (28.6% versus 11.6%; p < 0.001), and intensive care unit (30.3% versus 14.9%; p = 0.002), but not with mortality; by contrast, there was no statistically significant association between SHR and all these parameters. Our results are in agreement with the literature regarding the impact of absolute hyperglycemia on COVID-19 severity outcomes, while SHR was not a significant marker. We therefore suggest that SHR should not be evaluated in all patients admitted in the hospital for COVID-19, and we encourage the standard measures at admission of blood glucose and HbA1c levels.info:eu-repo/semantics/publishedVersio

The Asiago-ESO/RASS QSO Survey. III. Clustering analysis and its theoretical interpretation

This is the third paper of a series describing the Asiago-ESO/RASS QSO survey (AERQS), a project aimed at the construction of an all-sky statistically well-defined sample of relatively bright QSOs (B<15) at z<0.3. We present here the clustering analysis of the full spectroscopically identified database (392 AGN). The clustering signal at 0.02<z<0.22 is detected at a 3-4 sigma level and its amplitude is measured to be r_0=8.6\pm 2.0 h^{-1} Mpc (in a LambdaCDM model). The comparison with other classes of objects shows that low-redshift QSOs are clustered in a similar way to Radio Galaxies, EROs and early-type galaxies in general, although with a marginally smaller amplitude. The comparison with recent results from the 2QZ shows that the correlation function of QSOs is constant in redshift or marginally increasing toward low redshift. We discuss this behavior with physically motivated models, deriving interesting constraints on the typical mass of the dark matter halos hosting QSOs, M_DMH= 10^{12.7} h^{-1} M_sun (10^{12.0}-10^{13.5}h^{-1} M_sun at 1 sigma confidence level). Finally, we use the clustering data to infer the physical properties of local AGN, obtaining M_BH=2 10^8 h^{-1} M_sun (10^7-3 10^9 h^{-1} M_sun) for the mass of the active black holes, tau_{AGN}= 8 10^6 yr (2 10^{6}-5 10^{7} yr) for their life-time and eta = 0.14 for their efficiency (always for a LambdaCDM model).Comment: 37 pages, Astronomical Journal in press. Changes to match the referee comment

Role of cGMP and cAMP in the hemodynamic response to intrathecal sildenafil administration

INTRODUCTION: Results from our laboratory have demonstrated that intracerebroventricular administration of sildenafil to conscious rats promoted a noticeable increase in both lumbar sympathetic activity and heart rate, with no change in the mean arterial pressure. The intracerebroventricular administration of sildenafil may have produced the hemodynamic effects by activating sympathetic preganglionic neurons in the supraspinal regions and spinal cord. It is well documented that sildenafil increases intracellular cGMP levels by inhibiting phosphodiesterase type 5 and increases cAMP levels by inhibiting other phosphodiesterases. OBJECTIVE: To examine and compare, in conscious rats, the hemodynamic response following the intrathecal administration of sildenafil, 8-bromo-cGMP (an analog of cGMP), forskolin (an activator of adenylate cyclase), or dibutyryl-cAMP (an analog of cAMP) in order to elucidate the possible role of the sympathetic preganglionic neurons in the observed hemodynamic response. RESULTS: The hemodynamic responses observed following intrathecal administration of the studied drugs demonstrated the following: 1) sildenafil increased the mean arterial pressure and heart rate in a dose-dependent manner, 2) increasing doses of 8-bromo-cGMP did not alter the mean arterial pressure and heart rate, 3) forskolin did not affect the mean arterial pressure but did increase the heart rate and 4) dibutyryl-cAMP increased the mean arterial pressure and heart rate, similar to the effect observed following the intrathecal injection of the highest dose of sildenafil. CONCLUSION: Overall, the findings of the current study suggest that the cardiovascular response following the intrathecal administration of sildenafil to conscious rats involves the inhibition of phosphodiesterases other than phosphodiesterase type 5 that increase the cAMP level and the activation of sympathetic preganglionic neurons

Structural determination of Bi-doped magnetite multifunctional nanoparticles for contrast imaging

To determine with precision how Bi atoms are distributed in Bi-doped iron oxide nanoparticles their structural characterization has been carried out by X-ray absorption spectroscopy (XAS) recorded at the K edge of Fe and at the L edge of Bi. The inorganic nanoparticles are nominally hybrid structures integrating an iron oxide core and a bismuth oxide shell. Fe K-edge XAS indicates the formation of a structurally ordered, non-stoichiometric magnetite (FeO) phase for all the nanoparticles. The XAS spectra show that, in the samples synthesized by precipitation in aqueous media and laser pyrolysis, the Bi atoms neither enter into the iron oxide spinel lattice nor form any other mixed Bi-Fe oxides. No modification of the local structure around the Fe atoms induced by the Bi atoms is observed at the Fe K edge. In addition, contrary to expectations, our results indicate that the Bi atoms do not form a well-defined Bi oxide structure. The XAS study at the Bi L edge indicates that the environment around Bi atoms is highly disordered and only a first oxygen coordination shell is observed. Indefinite [BiO(OH)] units (isolated or aggregated forming tiny amorphous clusters) bonded through hydroxyl bridges to the nanoparticle, rather than a well defined BiO shell, surround the nanoparticle. On the other hand, the XAS study indicates that, in the samples synthesized by thermal decomposition, the Bi atoms are embedded in a longer range ordered structure showing the first and second neighbors

Penalized likelihood and multi-objective spatial scans for the detection and inference of irregular clusters

Background: Irregularly shaped spatial clusters are difficult to delineate. A cluster found by an algorithm often spreads through large portions of the map, impacting its geographical meaning. Penalized likelihood methods for Kulldorff's spatial scan statistics have been used to control the excessive freedom of the shape of clusters. Penalty functions based on cluster geometry and non-connectivity have been proposed recently. Another approach involves the use of a multi-objective algorithm to maximize two objectives: the spatial scan statistics and the geometric penalty function. Results & Discussion: We present a novel scan statistic algorithm employing a function based on the graph topology to penalize the presence of under-populated disconnection nodes in candidate clusters, the disconnection nodes cohesion function. A disconnection node is defined as a region within a cluster, such that its removal disconnects the cluster. By applying this function, the most geographically meaningful clusters are sifted through the immense set of possible irregularly shaped candidate cluster solutions. To evaluate the statistical significance of solutions for multi-objective scans, a statistical approach based on the concept of attainment function is used. In this paper we compared different penalized likelihoods employing the geometric and non-connectivity regularity functions and the novel disconnection nodes cohesion function. We also build multi-objective scans using those three functions and compare them with the previous penalized likelihood scans. An application is presented using comprehensive state-wide data for Chagas' disease in puerperal women in Minas Gerais state, Brazil. Conclusions: We show that, compared to the other single-objective algorithms, multi-objective scans present better performance, regarding power, sensitivity and positive predicted value. The multi-objective non-connectivity scan is faster and better suited for the detection of moderately irregularly shaped clusters. The multi-objective cohesion scan is most effective for the detection of highly irregularly shaped clusters

CMB Anisotropies at Second Order I

We present the computation of the full system of Boltzmann equations at second-order describing the evolution of the photon, baryon and cold dark matter fluids. These equations allow to follow the time evolution of the Cosmic Microwave Background (CMB) anisotropies at second-order at all angular scales from the early epoch, when the cosmological perturbations were generated, to the present through the recombination era. This paper sets the stage for the computation of the full second-order radiation transfer function at all scales and for a a generic set of initial conditions specifying the level of primordial non-Gaussianity. In a companion paper, we will present the computation of the three-point correlation function at recombination which is so relevant for the issue of non-Gaussianity in the CMB anisotropies.Comment: 26 pages, LaTeX file, typos correcte

Patterns of immigration in the new immigration countries

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