Central urocortin activation of sympathetic-regulated energy metabolism in Wistar rats

The corticotropin-releasing hormone (CRH) system, including CRH and urocortin (UCN), is implicated in the central control of appetite and energy metabolism. Urocortin, a recently isolated neuropeptide closely related to CRH is involved in the central signaling cascade that inhibits energy intake. When administered intracerebroventricularly and intra-hypothalamically, UCN potently decreases food intake. Receptors for UCN, while widely distributed, are expressed in hypothalamic nuclei. As the hypothalamus is involved in modulating autonomic outflow, UCN may also act as a catabolic neuropeptide to facilitate energy expenditure through sympathetic-regulated thermogenesis. To test the hypothesis that UCN also enhances regulatory energy expenditure via the activation of the sympathetic nervous system, we examined whole body oxygen consumption (VO2) and colonic temperature in male Wistar rats in response to central UCN administration. That is, the intracerebroventricular injection of 1.0 μg of UCN in male Wistar rats (n=10) significantly increased whole body oxygen consumption compared to PBS control. In addition, colonic temperature was significantly increased (Δ0.7±0.08 °C) in UCN- vs. PBS-administered rats, which was prevented by pretreatment with the ganglionic blocker chlorisondamine. These studies suggest that UCN acutely increased whole body oxygen consumption and body temperature via central activation of sympathetic outflow

ISO observations of a sample of Compact Steep Spectrum and GHz Peaked Spectrum Radio Galaxies

We present results from observations obtained with ISOPHOT, on board the ISO satellite, of a representative sample of seventeen CSS/GPS radio galaxies and of a control sample of sixteen extended radio galaxies spanning similar ranges in redshift (0.2 = 10^26 W/Hz). The observations have been performed at lambda = 60, 90, 174 and 200 microns. Seven of the CSS/GPS sources have detections >= 3 sigma at one or more wavelengths, one of which is detected at >= 5 sigma. By co-adding the data we have obtained average flux densities at the four wavelengths. We found no evidence that the FIR luminosities of the CSS/GPS sources are significantly different from those of the extended objects and therefore there is not any support for CSS/GPS sources being objects "frustrated" by an abnormally dense ambient medium. The two samples were then combined, providing FIR information on a new sample of radio galaxies at intermediate redshifts. We compare this information with what previously known from IRAS and discuss the average properties of radio galaxies in the redshift range 0.2 - 0.8. The FIR emission cannot be accounted for by extrapolation of the synchrotron radio spectrum and we attribute it to thermal dust emission. The average FIR luminosity is >= 6*10^11 L_sun. Over the observed frequency range the infrared spectrum can be described by a power law with spectral index alpha >~1.0 +/- 0.2. Assuming the emission to be due to dust, a range of temperatures is required, from >=80 K to \~25 K. The dust masses required to explain the FIR emission range from 5*10^5 M_sun for the hotter component up to 2*10^8 M_sun for the colder one. (abridged)Comment: Astronomy & Astrophysics, in press, 16 pages, 2 Figure

The B3-VLA CSS sample. VIII: New optical identifications from the Sloan Digital Sky Survey. The ultraviolet-optical spectral energy distribution of the young radio sources

Compact steep-spectrum radio sources and giga-hertz peaked spectrum radio sources (CSS/GPS) are generally considered to be mostly young radio sources. In recent years we studied at many wavelengths a sample of these objects selected from the B3-VLA catalog: the B3-VLA CSS sample. Only ~ 60 % of the sources were optically identified. We aim to increase the number of optical identifications and study the properties of the host galaxies of young radio sources. We cross-correlated the CSS B3-VLA sample with the Sloan Digital Sky Survey (SDSS), DR7, and complemented the SDSS photometry with available GALEX (DR 4/5 and 6) and near-IR data from UKIRT and 2MASS. We obtained new identifications and photometric redshifts for eight faint galaxies and for one quasar and two quasar candidates. Overall we have 27 galaxies with SDSS photometry in five bands, for which we derived the ultraviolet-optical spectral energy distribution (UV-O-SED). We extended our investigation to additional CSS/GPS selected from the literature. Most of the galaxies show an excess of ultra-violet (UV) radiation compared with the UV-O-SED of local radio-quiet ellipticals. We found a strong dependence of the UV excess on redshift and analyzed it assuming that it is generated either from the nucleus (hidden quasar) or from a young stellar population (YSP). We also compare the UV-O-SEDs of our CSS/GPS sources with those of a selection of large size (LSO) powerful radio sources from the literature. If the major process of the UV excess is caused by a YSP, our conclusion is that it is the result of the merger process that also triggered the onset of the radio source with some time delay. We do not see evidence for a major contribution from a YSP triggered by the radio sources itself.Comment: 38 pages, 21 figures, 6 tables. Accepted for publication on A&

Optical spectroscopy of faint gigahertz peaked spectrum sources

We present spectroscopic observations of a sample of faint Gigahertz Peaked Spectrum (GPS) radio sources drawn from the Westerbork Northern Sky Survey (WENSS). Redshifts have been determined for 19 (40%) of the objects. The optical spectra of the GPS sources identified with low redshift galaxies show deep stellar absorption features. This confirms previous suggestions that their optical light is not significantly contaminated by AGN-related emission, but is dominated by a population of old (>9 Gyr) and metal-rich (>0.2 [Fe/H]) stars, justifying the use of these (probably) young radio sources as probes of galaxy evolution. The optical spectra of GPS sources identified with quasars are indistinguishable from those of flat spectrum quasars, and clearly different from the spectra of Compact Steep Spectrum (CSS) quasars. The redshift distribution of the GPS quasars in our radio-faint sample is comparable to that of the bright samples presented in the literature, peaking at z ~ 2-3. It is unlikely that a significant population of low redshift GPS quasars is missed due to selection effects in our sample. We therefore claim that there is a genuine difference between the redshift distributions of GPS galaxies and quasars, which, because it is present in both the radio-faint and bright samples, can not be due to a redshift-luminosity degeneracy. It is therefore unlikely that the GPS quasars and galaxies are unified by orientation, unless the quasar opening angle is a strong function of redshift. We suggest that the GPS quasars and galaxies are unrelated populations and just happen to have identical observed radio-spectral properties, and hypothesise that GPS quasars are a sub-class of flat spectrum quasars.Comment: LaTeX, 13 pages. Accepted by MNRAS. For related papers see http://www.ast.cam.ac.uk/~snelle

Encephalitis due to herpes zoster without rash in an immunocompetent 12-year-old girl: Case report and review of the literature

Background: Neurological complications due to reactivation of varicella-zoster virus (VZV) are very uncommon in immunocompetent patients. Generally a vesicular rash is present on one or more dermatomes, preceding or following the main manifestation. Few cases are reported in the international literature, but they concern mainly adult or elderly patients. Case presentation: A 12-year-old girl was referred to our hospital for persisting headache, cough and rhinitis for six days. After first examination, diagnosis of anterior sinusitis was made by nasal endoscopy. The day after, the girl developed psychotic symptoms and altered mental status. Computed tomography (CT) scan was immediately performed but was unremarkable; lumbar puncture revealed leukocytosis with lymphocytic predominance and cerebrospinal fluid polymerase chain reaction (PCR) detected varicella-zoster virus DNA. The diagnosis of acute VZV encephalitis was made. The patient was promptly treated with acyclovir infused intravenously and her clinical conditions rapidly improved. Tests made did not show any condition of immunosuppression. Conclusions: Although if rare, reactivation of VZV can occur in immunocompetent children and its complications can involve central nervous system. Among these complications, meningitis is more common, but cerebral parenchyma can also be involved leading to a severe medical condition that is defined meningoencephalitis. In rare cases vesicular rash may be absent; therefore high level of suspicion is required even in those patients in which suggestive clinical features are not present to guide the diagnosis. Intravenous acyclovir represents the treatment of choice to obtain a fast clinical response and to prevent the onset of late-term complications

HST images of B2 radio galaxies: the link between circum-nuclear dust and radio properties

We discuss HST images in V and I of radio galaxies selected from the B2 sample of low luminosity radio galaxies. Absorption maps were constructed which highlight the presence of circumnuclear dust on scales of typically few kpc or less.Comment: 4 pages, 4 figures, in "The Central kpc of Starbursts and AGN: The La Palma Connection", ASP Conf Series, in press, eds J.H. Knapen, J.E. Beckman, I. Shlosman and T.J. Mahone

Adiabatic relativistic models for the jets in the radio galaxy 3C 31

We present a general approach to the modelling of the brightness and polarization structures of adiabatic, decelerating relativistic jets, based on the formalism of Matthews & Scheuer (1990). We compare the predictions of adiabatic jet models with deep, high-resolution observations of the radio jets in the FR I radio galaxy 3C 31. Adiabatic models require coupling between the variations of velocity, magnetic field and particle density. They are therefore more tightly constrained than the models previously presented for 3C 31 by Laing & Bridle (2002). We show that adiabatic models provide a poorer description of the data in two crucial respects: they cannot reproduce the observed magnetic-field structures in detail, and they also predict too steep a brightness decline along the jets for plausible variations of the jet velocity. We find that the innermost regions of the jets show the strongest evidence for non-adiabatic behaviour, and that the adiabatic models provide progressively better descriptions of the jet emission at larger distances from the galactic nucleus. We briefly discuss physical processes which might contribute to this non-adiabatic behaviour. In particular, we develop a parameterized description of distributed particle injection, which we fit to the observed total intensities. We show that particles are preferentially injected where bright X-ray emission is observed, and where we infer that the jets are over-pressured.Comment: 16 pages, 11 figures, accepted for publication in MNRA

High Frequency Peakers: young radio sources or flaring blazars?

We present new, simultaneous, multifrequency observations of 45 out of the 55 candidate High Frequency Peakers (HFP) selected by Dallacasa et al. (2000), carried out 3 to 4 years after a first set of observations. Our sub-sample consists of 10 galaxies, 28 stellar objects (``quasars'') and 7 unidentified sources. Both sets of observations are sensitive enough to allow the detection of variability at the 10% level or lower. While galaxies do not show significant variability, most quasars do. Seven of them no longer show the convex spectrum which is the defining property of Gigahertz Peaked Spectrum (GPS)/HFP sources and are interpreted as blazars caught by Dallacasa et al. (2000) during a flare, when a highly self-absorbed component dominated the emission. In general, the variability properties (amplitude, timescales, correlation between peak luminosity and peak frequency of the flaring component) of the quasar sub-sample resemble those of blazars. We thus conclude that most HFP candidates identified with quasars may well be flaring blazars.Comment: 20 pages, 18 figures, accepted for publication in Astronomy & Astrophysic

Avaliação agronômico de coleção de guandu (Cajanus Cajan(L.)Millsp) forrageiro proveniente do ICRISAT.

Com a finalidade de avaliar agronomicamente coleção de guandu fornecida pelo Internacional Crops Research Institute for the Semi-arid Tropics, ICRISAT, India, foi instalado ensaio em blocos ao acaso, com 3 repetições e 76 tratamentos.Resum