Radiation effects on shock propagation in Al target relevant to equation of state measurements

We present one-dimensional simulations performed using the multi group radiation hydro code MULTI with the goal of analyzing the target preheating effect under conditions similar to those of recent experiments aimed at studying the Equation of State (EOS) of various materials. In such experiments, aluminum is often used as reference material; therefore its behavior under strong shock compression and high-intensity laser irradiation (1013–1014 W/cm2) should be studied in detail. Our results reveal that at high laser irradiance, the laser energy available to induce shock pressure is reduced due to high X-rays generation. Simultaneously X-rays preheat the bulk of the reference material causing significant heating prior to shock propagation. Such effects induce deviations in shock propagation with respect to cold aluminum

Quark Mass Matrices with Four and Five Texture Zeroes, and the CKM Matrix, in terms of Mass Eigenvalues

Using the triangular matrix techniques of Kuo et al and Chiu et al for the four and five texture zero cases, with vanishing (11) elements for U and D matrices, it is shown, from the general eigenvalue equations and hierarchy conditions, that the quark mass matrices, and the CKM matrix can be expressed (except for the phases) entirely in terms of quark masses. The matrix structures are then quite simple and transparent. We confirm their results for the five texture zero case but find, upon closer examination of all the CKM elements which our results provide, that six of their nine patterns for the four texture zero case are not compatible with experiments. In total, only one five-texture zero and three four-texture zero patterns are allowed.Comment: 15 pages, 3 table

High-Redshift Dust Obscured Galaxies: A Morphology-Spectral Energy Distribution Connection Revealed by Keck Adaptive Optics

A simple optical to mid-IR color selection, R – [24]>14, i.e., f_ν(24 μm)/f_ν(R) ≳ 1000, identifies highly dust obscured galaxies (DOGs) with typical redshifts of z ~ 2 ± 0.5. Extreme mid-IR luminosities (L_(IR) > 10^(12-14)) suggest that DOGs are powered by a combination of active galactic nuclei (AGNs) and star formation, possibly driven by mergers. In an effort to compare their photometric properties with their rest-frame optical morphologies, we obtained high-spatial resolution (0."05-0."1) Keck Adaptive Optics K'-band images of 15 DOGs. The images reveal a wide range of morphologies, including small exponential disks (eight of 15), small ellipticals (four of 15), and unresolved sources (two of 15). One particularly diffuse source could not be classified because of low signal-to-noise ratio. We find a statistically significant correlation between galaxy concentration and mid-IR luminosity, with the most luminous DOGs exhibiting higher concentration and smaller physical size. DOGs with high concentration also tend to have spectral energy distributions (SEDs) suggestive of AGN activity. Thus, central AGN light may be biasing the morphologies of the more luminous DOGs to higher concentration. Conversely, more diffuse DOGs tend to show an SED shape suggestive of star formation. Two of 15 in the sample show multiple resolved components with separations of ~1 kpc, circumstantial evidence for ongoing mergers

The Spectral Energy Distribution and Infrared Luminosities of z ≈ 2 Dust-obscured Galaxies from Herschel and Spitzer

Dust-obscured galaxies (DOGs) are a subset of high-redshift (z ≈ 2) optically-faint ultra-luminous infrared galaxies (ULIRGs, e.g., L_(IR) > 10^(12) L_☉). We present new far-infrared photometry, at 250, 350, and 500 μm (observed-frame), from the Herschel Space Telescope for a large sample of 113 DOGs with spectroscopically measured redshifts. Approximately 60% of the sample are detected in the far-IR. The Herschel photometry allows the first robust determinations of the total infrared luminosities of a large sample of DOGs, confirming their high IR luminosities, which range from 10^(11.6) L_☉ 10^(13) L_☉. The rest-frame near-IR (1-3 μm) spectral energy distributions (SEDs) of the Herschel-detected DOGs are predictors of their SEDs at longer wavelengths. DOGs with "power-law" SEDs in the rest-frame near-IR show observed-frame 250/24 μm flux density ratios similar to the QSO-like local ULIRG, Mrk 231. DOGs with a stellar "bump" in their rest-frame near-IR show observed-frame 250/24 μm flux density ratios similar to local star-bursting ULIRGs like NGC 6240. None show 250/24 μm flux density ratios similar to extreme local ULIRG, Arp 220; though three show 350/24 μm flux density ratios similar to Arp 220. For the Herschel-detected DOGs, accurate estimates (within ~25%) of total IR luminosity can be predicted from their rest-frame mid-IR data alone (e.g., from Spitzer observed-frame 24 μm luminosities). Herschel-detected DOGs tend to have a high ratio of infrared luminosity to rest-frame 8 μm luminosity (the IR8 = L_(IR)(8-1000 μm)/νL_ν(8 μm) parameter of Elbaz et al.). Instead of lying on the z = 1-2 "infrared main sequence" of star-forming galaxies (like typical LIRGs and ULIRGs at those epochs) the DOGs, especially large fractions of the bump sources, tend to lie in the starburst sequence. While, Herschel-detected DOGs are similar to scaled up versions of local ULIRGs in terms of 250/24 μm flux density ratio, and IR8, they tend to have cooler far-IR dust temperatures (20-40 K for DOGs versus 40-50 K for local ULIRGs) as measured by the rest-frame 80/115 μm flux density ratios (e.g., observed-frame 250/350 μm ratios at z = 2). DOGs that are not detected by Herschel appear to have lower observed-frame 250/24 μm ratios than the detected sample, either because of warmer dust temperatures, lower IR luminosities, or both

Helios-2 Vela-Ariel-5 gamma-ray burst source position

The gamma-ray burst of 28 January 1976, one of 18 events thus far detected in interplanetary space with Helios-2, was also observed with the Vela-5A, -6A and the Ariel-5 satellites. A small source field is obtained from the intersection of the region derived from the observed time delays between Helios-2 and Vela-5A and -6A with the source region independently found with the Ariel-5 X-ray detector. This area contains neither any steady X-ray source as scanned by HEAO-A nor any previously catalogued X-ray, radio or infrared sources, X-ray transients, quasars, seyferts, globular clusters, flare stars, pulsars, white dwarfs or high energy gamma-ray sources. The region is however, within the source field of a gamma-ray transient observed in 1974, which exhibited nuclear gamma-ray line structure

Help-seeking behaviours, opportunistic treatment and psychological implications of adolescent acne: cross-sectional studies in schools and hospital outpatient departments in the UK

BACKGROUND: Acne vulgaris (acne) is a common adolescent skin condition. It is associated with negative psychological impacts and sufferers do not easily seek help, hence is undertreated. OBJECTIVES: We investigated the self-reported prevalence, severity and psychological sequelae of acne, together with assessing help-seeking behaviour and its barriers, in separate school and hospital samples. We explored opportunistic treatment by paediatricians. METHODS: Self-reported survey with participants drawn from: (1) 120 adolescents aged 13–18 in a London tertiary paediatric outpatient department and (2) 482 adolescents from two London schools, aged 11–18. Adolescents confidentially and anonymously completed a questionnaire (paper or online) and those with acne completed the Cardiff Acne Disability Index (CADI) questionnaire. OUTCOME MEASURES: To explore if acne is being addressed opportunistically in outpatient appointments and the behaviours associated with seeking help and psychological implications of acne. RESULTS: Acne prevalence was reported as 58.3% in the clinic and 42.3% in schools, with 34.3% and 20.6% of participants having moderate acne (MA) or severe acne (SA), respectively. The correlation between acne severity and CADI was significant (regression coefficient=4.86, p<0.005 (MA) and 9.08, p<0.005 (SA) in the hospital; 1.92, p<0.001 (MA) and 7.41, p<0.005 (SA) in schools). Severity of acne was associated with increased likelihood of seeing a doctor in both samples (OR=8.95, 2.79–28.70 (MA) in the clinic and 1.31, 1.30–2.90 (MA) and 3.89, 0.66–22.98 (SA) in the community). Barriers to help seeking included embarrassment and believing doctors were unapproachable. Doctors addressed acne opportunistically in 2.9% of the sample, although 16.7% of those with MA and SA wished their doctor had raised it. CONCLUSION: Acne is common and has negative psychological implications, correlating with severity. Young people often forego seeking help and hospital clinicians rarely address acne opportunistically. Further work is needed to investigate how to reduce barriers to help seeking for acne

The Star Formation Histories of z ~ 2 Dust-obscured Galaxies and Submillimeter-selected Galaxies

The Spitzer Space Telescope has identified a population of ultraluminous infrared galaxies (ULIRGs) at z ~ 2 that may play an important role in the evolution of massive galaxies. We measure the stellar masses (M_*) of two populations of Spitzer-selected ULIRGs that have extremely red R – [24] colors (dust-obscured galaxies, or DOGs) and compare our results with submillimeter-selected galaxies (SMGs). One set of 39 DOGs has a local maximum in their mid-infrared (mid-IR) spectral energy distribution (SED) at rest frame 1.6 μm associated with stellar emission ("bump DOGs"), while the other set of 51 DOGs have power-law mid-IR SEDs that are typical of obscured active galactic nuclei ("power-law DOGs"). We measure M_* by applying Charlot & Bruzual stellar population synthesis models to broadband photometry in the rest-frame ultraviolet, optical, and near-infrared of each of these populations. Assuming a simple stellar population and a Chabrier initial mass function, we find that power-law DOGs and bump DOGs are on average a factor of 2 and 1.5 more massive than SMGs, respectively (median and inter-quartile M_* values for SMGs, bump DOGs, and power-law DOGs are log(M_*/M_☉) = 10.42^(+0.42)_(–0.36), 10.62^(+0.36)_(–0.32), and 10.71^(+0.40)_(–0.34), respectively). More realistic star formation histories drawn from two competing theories for the nature of ULIRGs at z ~ 2 (major merger versus smooth accretion) can increase these mass estimates by up to 0.5 dex. A comparison of our stellar masses with the instantaneous star formation rate (SFR) in these z ~ 2 ULIRGs provides a preliminary indication supporting high SFRs for a given M_*, a situation that arises more naturally in major mergers than in smooth accretion-powered systems

Immunohistochemical evidence of tissue hypoxia and astrogliosis in the rostral ventrolateral medulla of spontaneously hypertensive rats

Increased activity of the sympathetic nervous system has been highlighted as a key factor that contributes to the development and maintenance of arterial hypertension. However, the factors that precipitate sustained increases in sympathetic activity remain poorly understood. Resting tissue oxygen partial pressure (PtO2) in the brainstem of anesthetized spontaneously hypertensive rats (SHRs) has been shown to be lower than in normotensive rats despite normal levels of arterial PO2. A hypoxic environment in the brainstem has been postulated to activate astroglial signalling mechanisms in the rostral ventrolateral medulla (RVLM) which in turn increase the excitability of presympathetic neuronal networks. In this study, we assessed the expression of indirect markers of tissue hypoxia and astroglial cell activation in the RVLM of SHRs and age-matched normotensive Wistar rats. Immunohistochemical labelling for hypoxia-induced factor-1α (HIF-1α) and bound pimonidazole adducts revealed the presence of tissue hypoxia in the RVLM of SHRs. Double immunostaining showed co-localization of bound pimonidazole labelling in putative presympathetic C1 neurons and in astroglial cells. Quantification of glial fibrillary acidic protein (GFAP) immunofluorescence showed relatively higher number of astrocytes and increased GFAP mean grey value density, whilst semi-quantitative analysis of skeletonized GFAP-immunoreactive processes revealed greater % area covered by astrocytic processes in the RVLM of adult SHRs. In conclusion, the morphological findings of tissue hypoxia and astrogliosis within brainstem presympathetic neuronal networks in the SHR support previous observations, showing that low brainstem PtO2 and increased astroglial signalling in the RVLM play an important role in pathological sympathoexcitation associated with the development of arterial hypertension

Plasmin Regulation through Allosteric, Sulfated, Small Molecules

Plasmin, a key serine protease, plays a major role in clot lysis and extracellular matrix remodeling. Heparin, a natural polydisperse sulfated glycosaminoglycan, is known to allosterically modulate plasmin activity. No small allosteric inhibitor of plasmin has been discovered to date. We screened an in-house library of 55 sulfated, small glycosaminoglycan mimetics based on nine distinct scaffolds and varying number and positions of sulfate groups to discover several promising hits. Of these, a pentasulfated flavonoid-quinazolinone dimer 32 was found to be the most potent sulfated small inhibitor of plasmin (IC50 = 45 μM, efficacy = 100%). Michaelis-Menten kinetic studies revealed an allosteric inhibition of plasmin by these inhibitors. Studies also indicated that the most potent inhibitors are selective for plasmin over thrombin and factor Xa, two serine proteases in coagulation cascade. Interestingly, different inhibitors exhibited different levels of efficacy (40%–100%), an observation alluding to the unique advantage offered by an allosteric process. Overall, our work presents the first small, synthetic allosteric plasmin inhibitors for further rational design