444 research outputs found

    Chlorpromazine for schizophrenia: a Cochrane systematic review of 50 years of randomised controlled trials

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    BACKGROUND: Chlorpromazine (CPZ) remains one of the most common drugs used for people with schizophrenia worldwide, and a benchmark against which other treatments can be evaluated. Quantitative reviews are rare; this one evaluates the effects of chlorpromazine in the treatment of schizophrenia in comparison with placebo. METHODS: We sought all relevant randomised controlled trials (RCT) comparing chlorpromazine to placebo by electronic and reference searching, and by contacting trial authors and the pharmaceutical industry. Data were extracted from selected trials and, where possible, synthesised and random effects relative risk (RR), the number needed to treat (NNT) and their 95% confidence intervals (CI) calculated. RESULTS: Fifty RCTs from 1955–2000 were included with 5276 people randomised to CPZ or placebo. They constitute 2008 person-years spent in trials. Meta-analysis of these trials showed that chlorpromazine promotes a global improvement (n = 1121, 13 RCTs, RR 0.76 CI 0.7 to 0.9, NNT 7 CI 5 to 10), although a considerable placebo response is also seen. People allocated to chlorpromazine tended not to leave trials early in both the short (n = 945, 16 RCTs, RR 0.74 CI 0.5 to 1.1) and medium term (n = 1861, 25 RCTs, RR 0.79 CI 0.6 to 1.1). There were, however, many adverse effects. Chlorpromazine is sedating (n = 1242, 18 RCTs, RR 2.3 CI 1.7 to 3.1, NNH 6 CI 5 to 8), increases a person's chances of experiencing acute movement disorders, Parkinsonism and causes low blood pressure with dizziness and dry mouth. CONCLUSION: It is understandable why the World Health Organization (WHO) have endorsed and included chlorpromazine in their list of essential drugs for use in schizophrenia. Low- and middle-income countries may have more complete evidence upon which to base their practice compared with richer nations using recent innovations

    Gaps in the cloud cover? Comparing extinction measures in spiral disks

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    Dust in galaxies can be mapped by either the FIR/sub-mm emission, the optical or infrared reddening of starlight, or the extinction of a known background source. We compare two dust extinction measurements for a set of fifteen sections in thirteen nearby galaxies, to determine the scale of the dusty ISM responsible for disk opacity: one using stellar reddening and the other a known background source. In our earlier papers, we presented extinction measurements of 29 galaxies, based on calibrated counts of distant background objects identified though foreground disks in HST/WFPC2 images. For the 13 galaxies that overlap with the Spitzer Infrared Nearby Galaxies Survey (SINGS), we now compare these results with those obtained from an I-L color map. Our goal is to determine whether or not a detected distant galaxy indicates a gap in the dusty ISM, and hence to better understand the nature and geometry of the disk extinction. We find that distant galaxies are predominantly in low-extinction sections marked by the color maps, indicating that their number depends both on the cloud cover of {\it Spitzer}-resolved dust structures --mostly the spiral arms--and a diffuse, unresolved underlying disk. We note that our infrared color map (E[I-L]) underestimates the overall dust presence in these disks severely, because it implicitly assumes the presence of a dust screen in front of the stellar distribution.Comment: 22 pages, 2 figures, 3 tables, accepted for publication in A

    The Density and Temperature of Molecular Clouds in M33

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    We have observed the 12^{12}CO J=2-1, J=3-2, and 13^{13}CO J=2-1 lines in a sample of seven giant molecular clouds in the Local Group spiral galaxy M33. The 12^{12}CO/13^{13}CO J=2-1 line ratio is constant across the entire sample, while the observed 12^{12}CO J=3-2/J=2-1 line ratio has a weak dependence on the star formation environment of the cloud, with large changes in the line ratio seen only for clouds in the immediate vicinity of an extremely luminous HII region. A large velocity gradient analysis indicates that clouds without HII regions have temperatures of 10-20 K, clouds with HII regions have temperatures of 15-100 K, and the cloud in the giant HII region has a temperature of at least 100 K. Interestingly, the giant HII region appears capable of raising the kinetic temperature of the molecular gas only for clouds that are quite nearby (<100< 100 pc). The continuous change of physical conditions across the observed range of star formation environments suggests that the unusual physical conditions in the cloud in the giant HII region are due to post-star formation changes in the molecular gas, rather than intrinsic properties of the gas related to the formation of the giant HII region.Comment: 14 pages, aastex, 4 postscript figures; accepted for publication in ApJ; also available at http://www.physics.mcmaster.ca/Wilson_Preprint

    Infrared Spectral Energy Distributions of Nearby Galaxies

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    The Spitzer Infrared Nearby Galaxies Survey (SINGS) is carrying out a comprehensive multi-wavelength survey on a sample of 75 nearby galaxies. The 1-850um spectral energy distributions are presented using broadband imaging data from Spitzer, 2MASS, ISO, IRAS, and SCUBA. The infrared colors derived from the globally-integrated Spitzer data are generally consistent with the previous generation of models that were developed based on global data for normal star-forming galaxies, though significant deviations are observed. Spitzer's excellent sensitivity and resolution also allow a detailed investigation of the infrared spectral energy distributions for various locations within the three large, nearby galaxies NGC3031 (M81), NGC5194 (M51), and NGC7331. Strong correlations exist between the local star formation rate and the infrared colors f_nu(70um)/f_nu(160um) and f_nu(24um)/f_nu(160um), suggesting that the 24 and 70um emission are useful tracers of the local star formation activity level. Preliminary evidence indicates that variations in the 24um emission, and not variations in the emission from polycyclic aromatic hydrocarbons at 8um, drive the variations in the f_nu(8.0um)/f_nu(24um) colors within NGC3031, NGC5194, and NGC7331. If the galaxy-to-galaxy variations in spectral energy distributions seen in our sample are representative of the range present at high redshift then extrapolations of total infrared luminosities and star formation rates from the observed 24um flux will be uncertain at the factor-of-five level (total range). The corresponding uncertainties using the redshifted 8.0um flux (e.g. observed 24um flux for a z=2 source) are factors of 10-20. Considerable caution should be used when interpreting such extrapolated infrared luminosities.Comment: 32 pages including 16 figures; accepted for publication in the Astrophysical Journa

    The Calibration of Mid-Infrared Star Formation Rate Indicators

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    With the goal of investigating the degree to which the mid-infrared emission traces the star formation rate (SFR), we analyze Spitzer 8 um and 24 um data of star-forming regions in a sample of 33 nearby galaxies with available HST/NICMOS images in the Paschen-alpha (1.8756 um) emission line. The galaxies are drawn from the Spitzer Infrared Nearby Galaxies Survey (SINGS) sample, and cover a range of morphologies and a factor ~10 in oxygen abundance. Published data on local low-metallicity starburst galaxies and Luminous Infrared Galaxies are also included in the analysis. Both the stellar-continuum-subtracted 8 um emission and the 24 um emission correlate with the extinction-corrected Pa-alpha line emission, although neither relationship is linear. Simple models of stellar populations and dust extinction and emission are able to reproduce the observed non-linear trend of the 24 um emission versus number of ionizing photons, including the modest deficiency of 24 um emission in the low metallicity regions, which results from a combination of decreasing dust opacity and dust temperature at low luminosities. Conversely, the trend of the 8 um emission as a function of the number of ionizing photons is not well reproduced by the same models. The 8 um emission is contributed, in larger measure than the 24 um emission, by dust heated by non-ionizing stellar populations, in agreement with previous findings. Two SFR calibrations, one using the 24 um emission and the other using a combination of the 24 um and H-alpha luminosities (Kennicutt et al. 2007), are presented. No calibration is presented for the 8 um emission, because of its significant dependence on both metallicity and environment. The calibrations presented here should be directly applicable to systems dominated by on-going star formation.Comment: 67 pages, 15 figures, accepted for publication on the Astrophysical Journal; replacement contains: correction to equation 8; important tweaks to equation 9; various typos correcte

    Mid-Infrared IRS Spectroscopy of NGC 7331: A First Look at the SINGS Legacy

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    The nearby spiral galaxy NGC 7331 was spectrally mapped from 5-38um using all modules of Spitzer's IRS spectrograph. A strong new dust emission feature, presumed due to PAHs, was discovered at 17.1um. The feature's intensity is nearly half that of the ubiquitous 11.3um band. The 7-14um spectral maps revealed significant variation in the 7.7 and 11.3um PAH features between the stellar ring and nucleus. Weak [OIV] 25.9um line emission was found to be centrally concentrated in the nucleus, with an observed strength over 10% of the combined neon line flux, indicating an AGN or unusually active massive star photo-ionization. Two [SIII] lines fix the characteristic electron density in the HII regions at n_e < ~200 cm^-3. Three detected H_2 rotational lines, tracing warm molecular gas, together with the observed IR continuum, are difficult to match with standard PDR models. Either additional PDR heating or shocks are required to simultaneously match lines and continuum.Comment: 6 pages, 5 figures, accepted for publication in ApJS Spitzer Special Issu

    Warm molecular hydrogen in the Spitzer SINGS galaxy sample

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    (simplified) Results on the properties of warm H2 in 57 normal galaxies are derived from H2 rotational transitions, obtained as part of SINGS. This study extends previous extragalactic surveys of H2, the most abundant constituent of the molecular ISM, to more common systems (L_FIR = e7 to 6e10 L_sun) of all morphological and nuclear types. The S(1) transition is securely detected in the nuclear regions of 86% of SINGS galaxies with stellar masses above 10^9.5 M_sun. The derived column densities of warm H2 (T > ~100 K), even though averaged over kiloparsec-scale areas, are commensurate with those of resolved PDRs; the median of the sample is 3e20 cm-2. They amount to between 1% and >30% of the total H2. The power emitted in the sum of the S(0) to S(2) transitions is on average 30% of the [SiII] line power, and ~4e-4 of the total infrared power (TIR) within the same area for star-forming galaxies, which is consistent with excitation in PDRs. The fact that H2 emission scales tightly with PAH emission, even though the average radiation field intensity varies by a factor ten, can also be understood if both tracers originate predominantly in PDRs, either dense or diffuse. A large fraction of the 25 LINER/Sy targets, however, strongly depart from the rest of the sample, in having warmer H2 in the excited states, and an excess of H2 emission with respect to PAHs, TIR and [SiII]. We propose a threshold in H2 to PAH power ratios, allowing the identification of low-luminosity AGNs by an excess H2 excitation. A dominant contribution from shock heating is favored in these objects. Finally, we detect, in nearly half the star-forming targets, non-equilibrium ortho to para ratios, consistent with FUV pumping combined with incomplete ortho-para thermalization by collisions, or possibly non-equilibrium PDR fronts advancing into cold gas.Comment: ApJS, in pres

    Bioenergy as climate change mitigation option within a 2 °C target—uncertainties and temporal challenges of bioenergy systems

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    Bioenergy is given an important role in reaching national and international climate change targets. However, uncertainties relating to emission reductions and the timeframe for these reductions are increasingly recognised as challenges whether bioenergy can deliver the required reductions. This paper discusses and highlights the challenges and the importance of the real greenhouse gas (GHG) reduction potential of bioenergy systems and its relevance for a global 450 ppm CO2e stabilisation target in terms of uncertainties and temporal aspects. The authors aim to raise awareness and emphasise the need for dynamic and consequential approaches for the evaluation of climate change impacts of bioenergy systems to capture the complexity and challenges of their real emission reduction potential within a 2 °C target. This review does not present new research results. This paper shows the variety of challenges and complexity of the problem of achieving real GHG emission reductions from bioenergy systems. By reflecting on current evaluation methods of emissions and impacts from bioenergy systems, this review points out that a rethinking and going beyond static approaches is required, considering each bioenergy systems according to its own characteristics, context and feedbacks. With the development of knowledge and continuously changing systems, policies should be designed in a way that they provide a balance between flexibility to adapt to new information and planning security for investors. These will then allow considering if a bioenergy system will deliver the required emission saving in the appropriate timeframe or not

    The Nature of Infrared Emission in the Local Group Dwarf Galaxy NGC 6822 As Revealed by Spitzer

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    We present Spitzer imaging of the metal-deficient (Z ~30% Z_sun) Local Group dwarf galaxy NGC 6822. On spatial scales of ~130 pc, we study the nature of IR, H alpha, HI, and radio continuum emission. Nebular emission strength correlates with IR surface brightness; however, roughly half of the IR emission is associated with diffuse regions not luminous at H alpha (as found in previous studies). The global ratio of dust to HI gas in the ISM, while uncertain at the factor of ~2 level, is ~25 times lower than the global values derived for spiral galaxies using similar modeling techniques; localized ratios of dust to HI gas are about a factor of five higher than the global value in NGC 6822. There are strong variations (factors of ~10) in the relative ratios of H alpha and IR flux throughout the central disk; the low dust content of NGC 6822 is likely responsible for the different H alpha/IR ratios compared to those found in more metal-rich environments. The H alpha and IR emission is associated with high-column density (> ~1E21 cm^-2) neutral gas. Increases in IR surface brightness appear to be affected by both increased radiation field strength and increased local gas density. Individual regions and the galaxy as a whole fall within the observed scatter of recent high-resolution studies of the radio-far IR correlation in nearby spiral galaxies; this is likely the result of depleted radio and far-IR emission strengths in the ISM of this dwarf galaxy.Comment: ApJ, in press; please retrieve full-resolution version from http://www.astro.wesleyan.edu/~cannon/pubs.htm
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