191 research outputs found

    1-1 SFO and Hypothalamic Activation by

    Get PDF
    ABSTRACT Introduction/Hypothesis

    Empirical Photometric Redshifts of Luminous Red Galaxies and Clusters in SDSS

    Full text link
    In this work I discuss the necessary steps for deriving photometric redshifts for luminous red galaxies (LRGs) and galaxy clusters through simple empirical methods. The data used is from the Sloan Digital Sky Survey (SDSS). I show that with three bands only ({\it gri}) it is possible to achieve results as accurate as the ones obtained by other techniques, generally based on more filters. In particular, the use of the (g−i)(g-i) color helps improving the final redshifts (especially for clusters), as this color monotonically increases up to z∼0.8z \sim 0.8. For the LRGs I generate a catalog of ∼1.5\sim 1.5 million objects at z<0.70z < 0.70. The accuracy of this catalog is σ=0.027\sigma = 0.027 for z≤0.55z \le 0.55 and σ=0.049\sigma = 0.049 for 0.55<z≤0.700.55 < z \le 0.70. The photometric redshift technique employed for clusters is independent of a cluster selection algorithm. Thus, it can be applied to systems selected by any method or wavelength, as long as the proper optical photometry is available. When comparing the redshift listed in literature to the photometric estimate, the accuracy achieved for clusters is σ=0.024\sigma = 0.024 for z≤0.30z \le 0.30 and σ=0.037\sigma = 0.037 for 030<z≤0.55030 < z \le 0.55. However, when considering the spectroscopic redshift as the mean value of SDSS galaxies on each cluster region, the accuracy is at the same level as found by other authors: σ=0.011\sigma = 0.011 for z≤0.30z \le 0.30 and σ=0.016\sigma = 0.016 for 030<z≤0.55030 < z \le 0.55. The photometric redshift relation derived here is applied to thousands of cluster candidates selected elsewhere. I have also used galaxy photometric redshifts available in SDSS to identify groups in redshift space and then compare the redshift peak of the nearest group to each cluster redshift (ABRIDGED).Comment: 14 pages, 6 figures. Accepted to MNRAS. Minor changes in response to referee repor

    Over-expression of copper/zinc superoxide dismutase in the median preoptic nucleus attenuates chronic angiotensin II-induced hypertension in the rat.

    Get PDF
    The brain senses circulating levels of angiotensin II (AngII) via circumventricular organs, such as the subfornical organ (SFO), and is thought to adjust sympathetic nervous system output accordingly via this neuro-hormonal communication. However, the cellular signaling mechanisms involved in these communications remain to be fully understood. Previous lesion studies of either the SFO, or the downstream median preoptic nucleus (MnPO) have shown a diminution of the hypertensive effects of chronic AngII, without providing a clear explanation as to the intracellular signaling pathway(s) involved. Additional studies have reported that over-expressing copper/zinc superoxide dismutase (CuZnSOD), an intracellular superoxide (O2·-) scavenging enzyme, in the SFO attenuates chronic AngII-induced hypertension. Herein, we tested the hypothesis that overproduction of O2·- in the MnPO is an underlying mechanism in the long-term hypertensive effects of chronic AngII. Adenoviral vectors encoding human CuZnSOD (AdCuZnSOD) or control vector (AdEmpty) were injected directly into the MnPO of rats implanted with aortic telemetric transmitters for recording of arterial pressure. After a 3 day control period of saline infusion, rats were intravenously infused with AngII (10 ng/kg/min) for ten days. Rats over-expressing CuZnSOD (n = 7) in the MnPO had a blood pressure increase of only 6 ± 2 mmHg after ten days of AngII infusion while blood pressure increased 21 ± 4 mmHg in AdEmpty-infected rats (n = 9). These results support the hypothesis that production of O2·- in the MnPO contributes to the development of chronic AngII-dependent hypertension

    Angiotensin II-Induced Hypertension Is Attenuated by Overexpressing Copper/Zinc Superoxide Dismutase in the Brain Organum Vasculosum of the Lamina Terminalis.

    Get PDF
    Angiotensin II (AngII) can access the brain via circumventricular organs (CVOs), including the subfornical organ (SFO) and organum vasculosum of the lamina terminalis (OVLT), to modulate blood pressure. Previous studies have demonstrated a role for both the SFO and OVLT in the hypertensive response to chronic AngII, yet it is unclear which intracellular signaling pathways are involved in this response. Overexpression of copper/zinc superoxide dismutase (CuZnSOD) in the SFO has been shown to attenuate the chronic hypertensive effects of AngII. Presently, we tested the hypothesis that elevated levels of superoxide (O2 (∙-)) in the OVLT contribute to the hypertensive effects of AngII. To facilitate overexpression of superoxide dismutase, adenoviral vectors encoding human CuZnSOD or control adenovirus (AdEmpty) were injected directly into the OVLT of rats. Following 3 days of control saline infusion, rats were intravenously infused with AngII (10 ng/kg/min) for ten days. Blood pressure increased 33 ± 8 mmHg in AdEmpty rats (n = 6), while rats overexpressing CuZnSOD (n = 8) in the OVLT demonstrated a blood pressure increase of only 18 ± 5 mmHg after 10 days of AngII infusion. These results support the hypothesis that overproduction of O2 (∙-) in the OVLT plays an important role in the development of chronic AngII-dependent hypertension

    Angiotensin II-Induced Hypertension Is Attenuated by Overexpressing Copper/Zinc Superoxide Dismutase in the Brain Organum Vasculosum of the Lamina Terminalis

    Get PDF
    Angiotensin II (AngII) can access the brain via circumventricular organs (CVOs), including the subfornical organ (SFO) and organum vasculosum of the lamina terminalis (OVLT), to modulate blood pressure. Previous studies have demonstrated a role for both the SFO and OVLT in the hypertensive response to chronic AngII, yet it is unclear which intracellular signaling pathways are involved in this response. Overexpression of copper/zinc superoxide dismutase (CuZnSOD) in the SFO has been shown to attenuate the chronic hypertensive effects of AngII. Presently, we tested the hypothesis that elevated levels of superoxide (O2∙-) in the OVLT contribute to the hypertensive effects of AngII. To facilitate overexpression of superoxide dismutase, adenoviral vectors encoding human CuZnSOD or control adenovirus (AdEmpty) were injected directly into the OVLT of rats. Following 3 days of control saline infusion, rats were intravenously infused with AngII (10 ng/kg/min) for ten days. Blood pressure increased 33±8 mmHg in AdEmpty rats (n=6), while rats overexpressing CuZnSOD (n=8) in the OVLT demonstrated a blood pressure increase of only 18±5 mmHg after 10 days of AngII infusion. These results support the hypothesis that overproduction of O2∙- in the OVLT plays an important role in the development of chronic AngII-dependent hypertension

    The academic, economic and societal impacts of Open Access: an evidence-based review

    Get PDF
    Ongoing debates surrounding Open Access to the scholarly literature are multifaceted and complicated by disparate and often polarised viewpoints from engaged stakeholders. At the current stage, Open Access has become such a global issue that it is critical for all involved in scholarly publishing, including policymakers, publishers, research funders, governments, learned societies, librarians, and academic communities, to be well-informed on the history, benefits, and pitfalls of Open Access. In spite of this, there is a general lack of consensus regarding the potential pros and cons of Open Access at multiple levels. This review aims to be a resource for current knowledge on the impacts of Open Access by synthesizing important research in three major areas: academic, economic and societal. While there is clearly much scope for additional research, several key trends are identified, including a broad citation advantage for researchers who publish openly, as well as additional benefits to the non-academic dissemination of their work. The economic impact of Open Access is less well-understood, although it is clear that access to the research literature is key for innovative enterprises, and a range of governmental and non-governmental services. Furthermore, Open Access has the potential to save both publishers and research funders considerable amounts of financial resources, and can provide some economic benefits to traditionally subscription-based journals. The societal impact of Open Access is strong, in particular for advancing citizen science initiatives, and leveling the playing field for researchers in developing countries. Open Access supersedes all potential alternative modes of access to the scholarly literature through enabling unrestricted re-use, and long-term stability independent of financial constraints of traditional publishers that impede knowledge sharing. However, Open Access has the potential to become unsustainable for research communities if high-cost options are allowed to continue to prevail in a widely unregulated scholarly publishing market. Open Access remains only one of the multiple challenges that the scholarly publishing system is currently facing. Yet, it provides one foundation for increasing engagement with researchers regarding ethical standards of publishing and the broader implications of 'Open Research'

    Discovery of optically faint obscured quasars with Virtual Observatory tools

    Full text link
    We use Virtual Observatory (VO) tools to identify optically faint, obscured (i.e., type 2) active galactic nuclei (AGN) in the two Great Observatories Origins Deep Survey (GOODS) fields. By employing publicly available X-ray and optical data and catalogues we discover 68 type 2 AGN candidates. The X-ray powers of these sources are estimated by using a previously known correlation between X-ray luminosity and X-ray-to-optical flux ratio. Thirty-one of our candidates have high estimated powers (Lx > 10^44 erg/s) and therefore qualify as optically obscured quasars, the so-called ``QSO 2''. Based on the derived X-ray powers, our candidates are likely to be at relatively high redshifts, z ~ 3, with the QSO 2 at z ~ 4. By going ~ 3 magnitudes fainter than previously known type 2 AGN in the two GOODS fields we are sampling a region of redshift - power space which was previously unreachable with classical methods. Our method brings to 40 the number of QSO 2 in the GOODS fields, an improvement of a factor ~ 4 when compared to the only 9 such sources previously known. We derive a QSO 2 surface density down to 10^-15 erg/cm^2/s in the 0.5 - 8 keV band of >~ 330/deg^2, ~ 30% of which is made up of previously known sources. This is larger than current estimates and some predictions and suggests that the surface density of QSO 2 at faint flux limits has been underestimated. This work demonstrates that VO tools are mature enough to produce cutting-edge science results by exploiting astronomical data beyond ``classical'' identification limits (R <~ 25) with interoperable tools for statistical identification of sources using multiwavelength information.Comment: 16 pages, 6 figures, accepted for publication in Astronomy & Astrophysics. PDF file with higher resolution figures available at http://www.eso.org/~ppadovan/AVO-paper.pd

    Implementation of PhotoZ under Astro-WISE - A photometric redshift code for large datasets

    Full text link
    We describe the implementation of the PhotoZ code in the framework of the Astro-WISE package and as part of the Photometric Classification Server of the PanSTARRS pipeline. Both systems allow the automatic measurement of photometric redshifts for the millions of objects being observed in the PanSTARRS project or expected to be observed by future surveys like KIDS, DES or EUCLID.Comment: Accepted for publication in topical issue of Experimental Astronomy on Astro-WISE information system, references update

    The Relationship of the Facial Nerve to the Condylar Process: A Cadaveric Study with Implications for Open Reduction Internal Fixation

    Get PDF
    Introduction. The mandibular condyle is the most common site of mandibular fracture. Surgical treatment of condylar fractures by open reduction and internal fixation (ORIF) demands direct visualization of the fracture. This project aimed to investigate the anatomic relationship of the tragus to the facial nerve and condylar process. Materials and Methods. Twelve fresh hemicadavers heads were used. An extended retromandibular/preauricular approach was utilized, with the incision being based parallel to the posterior edge of the ramus. Measurements were obtained from the tragus to the facial nerve and condylar process. Results. The temporozygomatic division of the facial nerve was encountered during each approach, crossing the mandible at the condylar neck. The mean tissue depth separating the facial nerve from the condylar neck was 5.5 mm (range: 3.5 mm–7 mm, SD 1.2 mm). The upper division of the facial nerve crossed the posterior border of the condylar process on average 2.31 cm (SD 0.10 cm) anterior to the tragus. Conclusions. This study suggests that the temporozygomatic division of the facial nerve will be encountered in most approaches to the condylar process. As visualization of the relationship of the facial nerve to condyle is often limited, recognition that, on average, 5.5 mm of tissue separates condylar process from nerve should help reduce the incidence of facial nerve injury during this procedure

    Clustering of Radio Galaxies and Quasars

    Full text link
    We compute the cross-correlation between a sample of 14,000 radio-loud AGN (RLAGN) with redshifts between 0.4 and 0.8 selected from the Sloan Digital Sky Survey and a reference sample of 1.2 million luminous red galaxies in the same redshift range. We quantify how the clustering of radio-loud AGN depends on host galaxy mass and on radio luminosity. Radio-loud AGN are clustered more strongly on all scales than control samples of radio-quiet galaxies with the same stellar masses and redshifts, but the differences are largest on scales less than 1 Mpc. In addition, the clustering amplitude of the RLAGN varies significantly with radio luminosity on scales less than 1 Mpc. This proves that the gaseous environment of a galaxy on the scale of its dark matter halo, plays a key role in determining not only the probability that a galaxy is radio-loud AGN, but also the total luminosity of the radio jet. Next, we compare the clustering of radio galaxies with that of radio-loud quasars in the same redshift range. Unified models predict that both types of active nuclei should cluster in the same way. Our data show that most RLAGN are clustered more strongly than radio-loud QSOs, even when the AGN and QSO samples are matched in both black hole mass and radio luminosity. Only the most extreme RLAGN and RLQSOs in our sample, with radio luminosities in excess of 10^26 W/Hz, have similar clustering properties. The majority of the strongly evolving RLAGN population at z~0.5 are found in different environments to the quasars, and hence must be triggered by a different physical mechanism.Comment: 12 pages, 13 Figures, submitted to MNRA
    • …
    corecore