The Infrared Properties of Submillimeter Galaxies: Clues From Ultra-Deep 70 Micron Imaging

We present 70 micron properties of submillimeter galaxies (SMGs) in the Great Observatories Origins Deep Survey (GOODS) North field. Out of thirty submillimeter galaxies (S_850 > 2 mJy) in the central GOODS-N region, we find two with secure 70 micron detections. These are the first 70 micron detections of SMGs. One of the matched SMGs is at z ~ 0.5 and has S_70/S_850 and S_70/S_24 ratios consistent with a cool galaxy. The second SMG (z = 1.2) has infrared-submm colors which indicate it is more actively forming stars. We examine the average 70 micron properties of the SMGs by performing a stacking analysis, which also allows us to estimate that S_850 > 2 mJy SMGs contribute 9 +- 3% of the 70 micron background light. The S_850/S_70 colors of the SMG population as a whole is best fit by cool galaxies, and because of the redshifting effects these constraints are mainly on the lower z sub-sample. We fit Spectral Energy Distributions (SEDs) to the far-infrared data points of the two detected SMGs and the average low redshift SMG (z_{median}= 1.4). We find that the average low-z SMG has a cooler dust temperature than local ultraluminous infrared galaxies (ULIRGs) of similar luminosity and an SED which is best fit by scaled up versions of normal spiral galaxies. The average low-z SMG is found to have a typical dust temperature T = 21 -- 33 K and infrared luminosity L_{8-1000 micron} = 8.0 \times 10^11 L_sun. We estimate the AGN contribution to the total infrared luminosity of low-z SMGs is less than 23%.Comment: Accepted by ApJ. 14 pages, 6 figures. Minor revisions 20th Dec 200

The Radial Structure of SNR N103B

We report on the results from a Chandra ACIS observation of the young, compact, supernova remnant N103B. The unprecedented spatial resolution of Chandra reveals sub-arcsecond structure, both in the brightness and in spectral variations. Underlying these small-scale variations is a surprisingly simple radial structure in the equivalent widths of the strong Si and S emission lines. We investigate these radial variations through spatially resolved spectroscopy using a plane-parallel, non-equilibrium ionization model with multiple components. The majority of the emission arises from components with a temperature of 1 keV: a fully ionized hydrogen component; a high ionization timescale (n_e*t > 10^12 s cm^-3) component containing Si, S, Ar, Ca, and Fe; and a low ionization timescale (n_e*t ~ 10^{11} s cm^-3) O, Ne, and Mg component. To reproduce the strong Fe Kalpha line, it is necessary to include additional Fe in a hot (> 2 keV), low ionization (n_e*t ~ 10^10.8 s cm^-3) component. This hot Fe may be in the form of hot Fe bubbles, formed in the radioactive decay of clumps of 56Ni. We find no radial variation in the ionization timescales or temperatures of the various components. Rather, the Si and S equivalent widths increase at large radii because these lines, as well as those of Ar and Ca, are formed in a shell occupying the outer half of the remnant. A shell of hot Fe is located interior to this, but there is a large region of overlap between these two shells. In the inner 30% of the remnant, there is a core of cooler, 1 keV Fe. We find that the distribution of the ejecta and the yields of the intermediate mass species are consistent with model prediction for Type Ia events.Comment: 34 pages, including 7 tables and 7 figures, Accepted by Ap

The anatomy of exhumed river-channel belts: Bedform to belt‐scale river kinematics of the Ruby Ranch Member, Cretaceous Cedar Mountain Formation, Utah, USA

Many published interpretations of ancient fluvial systems have relied on observations of extensive outcrops of thick successions. This paper, in contrast, demonstrates that a regional understanding of palaeoriver kinematics, depositional setting and sedimentation rates can be interpreted from local sedimentological measurements of bedform and barform strata. Dune and bar strata, channel planform geometry and bed topography are measured within exhumed fluvial strata exposed as ridges in the Ruby Ranch Member of the Cretaceous Cedar Mountain Formation, Utah, USA. The ridges are composed of lithified stacked channel belts, representing at least five or six re‐occupations of a single‐strand channel. Lateral sections reveal well‐preserved barforms constructed of subaqueous dune cross‐sets. The topography of palaeobarforms is preserved along the top surface of the outcrops. Comparisons of the channel‐belt centreline to local palaeotransport directions indicate that channel planform geometry was preserved through the re‐occupations, rather than being obscured by lateral migration. Rapid avulsions preserved the state of the active channel bed and its individual bars at the time of abandonment. Inferred minimum sedimentation durations for the preserved elements, inferred from cross‐set thickness distributions and assumed bedform migration rates, vary within a belt from one to ten days. Using only these local sedimentological measurements, the depositional setting is interpreted as a fluvial megafan, given the similarity in river kinematics. This paper provides a systematic methodology for the future synthesis of vertical and planview data, including the drone‐equipped 2020 Mars Rover mission, to exhumed fluvial and deltaic strata

Ecosystem uptake and transfer of Sellafield-derived radiocarbon (14C). Part 1. The Irish Sea

Ecosystem uptake and transfer processes of Sellafield-derived radiocarbon (14C) within the Irish Sea were examined. Highly variable activities in sediment, seawater and biota indicate complex 14C dispersal and uptake dynamics. All east basin biota exhibited 14C enrichments above ambient background while most west basin biota had 14C activities close to background, although four organisms including two slow-moving species were significantly enriched. The western Irish Sea gyre is a suggested pathway for transfer of 14C to the west basin and retention therein. Despite ongoing Sellafield 14C discharges, organic sediments near Sellafield were significantly less enriched than associated benthic organisms. Rapid scavenging of labile, 14C-enriched organic material by organisms and mixing to depth of 14C-enriched detritus arriving at the sediment/water interface are proposed mechanisms to explain this. All commercially important fish, crustaceans and molluscs showed 14C enrichments above background; however, the radiation dose from their consumption is extremely low and radiologically insignificant

Illness-Related Cognition, Distress and Adjustment in Functional Stroke Symptoms, Vascular Stroke, and Chronic Fatigue Syndrome

Background: High rates of psychological distress are reported in functional conditions and vascular stroke, but there is limited understanding of how patients with functional neurological symptoms in stroke settings respond to symptoms. Aims: This study compared patients with functional stroke symptoms to those with vascular stroke and chronic fatigue syndrome (CFS). Methods: A prospective cohort of 56 patients with functional stroke symptoms were age-gender matched to patients with vascular stroke and CFS. Analysis of variance compared groups on cognitive and behavioral responses to symptoms, psychological distress, and functioning. Sensitivity analyses controlled for known confounders. The proportions of clinical anxiety and depression were compared between groups. Results: The functional stroke symptom group had a higher proportion of clinical anxiety cases than the CFS group, and a higher proportion of clinical depression cases than the vascular stroke group. Patients with functional stroke symptoms reported the highest rate of “damage beliefs” and “all-or-nothing” behaviors and greater symptom focusing and resting behavior than patients with vascular stroke. Limitations: Larger cohorts and a longitudinal design would strengthen study findings. Conclusion: Compared to patients with vascular stroke or CFS, patients with functional stroke symptoms show a somewhat distinct profile of illness-related beliefs and behaviors, as well as higher rates of clinical anxiety. Understanding such group differences provides some insights into aetiology and cognitive-behavioral responses. Appropriate support and referral should be available to patients with functional stroke symptoms to address distress and reduce the likelihood of severe impairment

Probing the Relation Between X-ray-Derived and Weak-Lensing-Derived Masses for Shear-Selected Galaxy Clusters: I. A781

We compare X-ray and weak-lensing masses for four galaxy clusters that comprise the top-ranked shear-selected cluster system in the Deep Lens Survey. The weak-lensing observations of this system, which is associated with A781, are from the Kitt Peak Mayall 4-m telescope, and the X-ray observations are from both Chandra and XMM-Newton. For a faithful comparison of masses, we adopt the same matter density profile for each method, which we choose to be an NFW profile. Since neither the X-ray nor weak-lensing data are deep enough to well constrain both the NFW scale radius and central density, we estimate the scale radius using a fitting function for the concentration derived from cosmological hydrodynamic simulations and an X-ray estimate of the mass assuming isothermality. We keep this scale radius in common for both X-ray and weak-lensing profiles, and fit for the central density, which scales linearly with mass. We find that for three of these clusters, there is agreement between X-ray and weak-lensing NFW central densities, and thus masses. For the other cluster, the X-ray central density is higher than that from weak-lensing by 2 sigma. X-ray images suggest that this cluster may be undergoing a merger with a smaller cluster. This work serves as an additional step towards understanding the possible biases in X-ray and weak-lensing cluster mass estimation methods. Such understanding is vital to efforts to constrain cosmology using X-ray or weak-lensing cluster surveys to trace the growth of structure over cosmic time.Comment: 14 pages, 7 figures, matches version in Ap

The GLINT10 field trial results

Autonomous underwater vehicles (AUVs) have gained more interest in recent years for military as well as civilian applications. One potential application of AUVs is for the purpose of undersea surveillance. As research into undersea surveillance using AUVs progresses, issues arise as to how an AUV acquires, acts on, and shares information about the undersea battle space. These issues naturally touch on aspects of vehicle autonomy and underwater communications, and need to be resolved through a spiral development process that includes at sea experimentation. This paper presents a recent AUV implementation for active anti-submarine warfare tested at sea in the summer of 2010. On-board signal processing capabilities and an adaptive behavior are discussed in both a simulation and experimental context. The implications for underwater surveillance using AUVs are discussed

Making sense of IL-6 signalling cues in pathophysiology

Unravelling the molecular mechanisms that account for functional pleiotropy is a major challenge for researchers in cytokine biology. Cytokine–receptor cross-reactivity and shared signalling pathways are considered primary drivers of cytokine pleiotropy. However, reports epitomized by studies of Jak-STAT cytokine signalling identify interesting biochemical and epigenetic determinants of transcription factor regulation that affect the delivery of signal-dependent cytokine responses. Here, a regulatory interplay between STAT transcription factors and their convergence to specific genomic enhancers support the fine-tuning of cytokine responses controlling host immunity, functional identity, and tissue homeostasis and repair. In this review, we provide an overview of the signalling networks that shape the way cells sense and interpret cytokine cues. With an emphasis on the biology of interleukin-6, we highlight the importance of these mechanisms to both physiological processes and pathophysiological outcomes

An Odorant Receptor from the Southern House Mosquito Culex pipiens quinquefasciatus Sensitive to Oviposition Attractants

Insect odorant receptors (ORs) are heteromers comprised of highly variable odorant-binding subunits associated with one conserved co-receptor. They are potential molecular targets for the development of novel mosquito attractants and repellents. ORs have been identified in the malaria mosquito, Anopheles gambiae, and in the yellow fever mosquito, Aedes aegypti. However, they are still unknown in the Southern house mosquito, Culex quinquefasciatus, which transmits pathogens that cause human diseases throughout the world, including West Nile Virus in the United States.We have employed a combination of bioinformatics, molecular cloning and electrophysiology approaches to identify and characterize the response profile of an OR in Cx. quinquefasciatus. First, we have unveiled a large multigenic family of one-hundred-fifty-eight putative ORs in this species, including a subgroup of conserved ORs in three mosquito species. Using the Xenopus oocytes expression system, we have determined the response profile of CquiOR2, an antennae-specific OR, which shares high identity with putative orthologs in Anopheles gambiae (AgamOR2) and Aedes aegypti (AaegOR2).We show that CquiOR2 is highly sensitive to indole, an oviposition attractant for Cx. quinquefasciatus. The response profile of CquiOR2 expressed in Xenopus oocytes resembles that of an olfactory receptor neuron housed in the antennal short blunt-tipped sensilla (A2) of Cx. quinquefasciatus, which are natural detectors for oviposition attractants. This first Culex OR de-orphanized is, therefore, a potential molecular target for screening oviposition attractants