The Late Time Light Curve of SN 1998bw Associated with GRB980425

We report 139 photometric observations through the B, V, and I filters of the supernova SN 1998bw, an object which is associated with the Gamma-Ray Burst GRB 980425. Detailed light curves of this unique supernova can be compared to theoretical models, so we report here our light curve for 123 days between 27 June 1998 and 28 October 1998. The light curve of SN 1988bw is consistent with those of the Type Ic class. We find that the magnitude-versus-time relation for this supernova is linear to within 0.05 mags in all colors over the entire duration of our study. Our measured uniform decline rates are $0.0141 \pm 0.0002$, $0.0184 \pm 0.0003$, and $0.0181 \pm 0.0003$ magnitudes per day in the B, V, and I bands. The linear decline and the rate of that decline suggest that late time light curve is powered by the radioactive decay of cobalt with some leakage of the gamma rays.Comment: 15 pages, 1 figure, 1 table, Accepted for publication in PAS

Chronoprints: Identifying Samples by Visualizing How They Change over Space and Time.

The modern tools of chemistry excel at identifying a sample, but the cost, size, complexity, and power consumption of these instruments often preclude their use in resource-limited settings. In this work, we demonstrate a simple and low-cost method for identifying a sample based on visualizing how the sample changes over space and time in response to a perturbation. Different types of perturbations could be used, and in this proof-of-concept we use a dynamic temperature gradient that rapidly cools different parts of the sample at different rates. We accomplish this by first loading several samples into long parallel channels on a "microfluidic thermometer chip." We then immerse one end of the chip in liquid nitrogen to create a dynamic temperature gradient along the channels, and we use an inexpensive USB microscope to record a video of how the samples respond to the changing temperature gradient. The video is then converted into several bitmap images (one per sample) that capture each sample's response to the perturbation in both space (the y-axis; the distance along the dynamic temperature gradient) and time (the x-axis); we call these images "chronological fingerprints" or "chronoprints" of each sample. If two samples' chronoprints are similar, this suggests that the samples are the same chemical substance or mixture, but if two samples' chronoprints are significantly different, this proves that the samples are chemically different. Since chronoprints are just bitmap images, they can be compared using a variety of techniques from computer science, and in this work we use three different image comparison algorithms to quantify chronoprint similarity. As a demonstration of the versatility of chronoprints, we use them in three different applications: distinguishing authentic olive oil from adulterated oil (an example of the over $10 billion global problem of food fraud), identifying adulterated or counterfeit medication (which represents around 10% of all medication in low- and middle-income countries), and distinguishing the occasionally confused pharmaceutical ingredients glycerol and diethylene glycol (whose accidental or intentional substitution has led to hundreds of deaths). The simplicity and versatility of chronoprints should make them valuable analytical tools in a variety of different fields

Metal-insulator transition in the one-dimensional Holstein model at half filling

We study the one-dimensional Holstein model with spin-1/2 electrons at half-filling. Ground state properties are calculated for long chains with great accuracy using the density matrix renormalization group method and extrapolated to the thermodynamic limit. We show that for small electron-phonon coupling or large phonon frequency, the insulating Peierls ground state predicted by mean-field theory is destroyed by quantum lattice fluctuations and that the system remains in a metallic phase with a non-degenerate ground state and power-law electronic and phononic correlations. When the electron-phonon coupling becomes large or the phonon frequency small, the system undergoes a transition to an insulating Peierls phase with a two-fold degenerate ground state, long-range charge-density-wave order, a dimerized lattice structure, and a gap in the electronic excitation spectrum.Comment: 6 pages (LaTex), 10 eps figure

An IR-Selected Galaxy Cluster at z = 1.41

We report the discovery of a galaxy cluster at z = 1.41. ISCS J143809+341419 was found in the Spitzer/IRAC Shallow Survey of the Bootes field in the NOAO Deep Wide-Field Survey carried out by IRAC. The cluster candidate was initially identified as a high density region of objects with photometric redshifts in the range 1.3 < z < 1.5. Optical spectroscopy of a limited number of objects in the region shows that 5 galaxies within a ~120 arcsec diameter region lie at z = 1.41 +/- 0.01. Most of these member galaxies have broad--band colors consistent with the expected spectral energy distribution of a passively--evolving elliptical galaxy formed at high redshift. The redshift of ISCS J143809+341419 is the highest currently known for a spectroscopically-confirmed cluster of galaxies.Comment: Accepted for publication in The Astrophysical Journal Letters; 5 pages and 5 figure

The Discovery of Three New z>5 Quasars in the AGN and Galaxy Evolution Survey

We present the discovery of three z>5 quasars in the AGN and Galaxy Evolution Survey (AGES) spectroscopic observations of the NOAO Deep Wide-Field Survey (NDWFS) Bootes Field. These quasars were selected as part of a larger Spitzer mid-infrared quasar sample with no selection based on optical colors. The highest redshift object, NDWFS J142516.3+325409, z=5.85, is the lowest-luminosity z>5.8 quasar currently known. We compare mid-infrared techniques for identifying z>5 quasars to more traditional optical techniques and show that mid-infrared colors allow for selection of high-redshift quasars even at redshifts where quasars lie near the optical stellar locus and at z>7 where optical selection is impossible. Using the superb multi-wavelength coverage available in the NDWFS Bootes field, we construct the spectral energy distributions (SEDs) of high-redshift quasars from observed Bw-band to 24 microns (rest-frame 600 Angstroms - 3.7 microns). We show that the three high-redshift quasars have quite similar SEDs, and the rest-frame composite SED of low-redshift quasars from the literature shows little evolution compared to our high-redshift objects. We compare the number of z>5 quasars we have discovered to the expected number from published quasar luminosity functions. While analyses of the quasar luminosity function are tenuous based on only three objects, we find that a relatively steep luminosity function with Psi L^(-3.2) provides the best agreement with the number of high-redshift quasars discovered in our survey.Comment: 9 page, 7 figures. Accepted for publication in A

The Impact of HAART on the Respiratory Complications of HIV Infection: Longitudinal Trends in the MACS and WIHS Cohorts

Objective: To review the incidence of respiratory conditions and their effect on mortality in HIV-infected and uninfected individuals prior to and during the era of highly active antiretroviral therapy (HAART). Design: Two large observational cohorts of HIV-infected and HIV-uninfected men (Multicenter AIDS Cohort Study [MACS]) and women (Women's Interagency HIV Study [WIHS]), followed since 1984 and 1994, respectively. Methods: Adjusted odds or hazards ratios for incident respiratory infections or non-infectious respiratory diagnoses, respectively, in HIV-infected compared to HIV-uninfected individuals in both the pre-HAART (MACS only) and HAART eras; and adjusted Cox proportional hazard ratios for mortality in HIV-infected persons with lung disease during the HAART era. Results: Compared to HIV-uninfected participants, HIV-infected individuals had more incident respiratory infections both pre-HAART (MACS, odds ratio [adjusted-OR], 2.4; 95% confidence interval [CI], 2.2-2.7; p<0.001) and after HAART availability (MACS, adjusted-OR, 1.5; 95%CI 1.3-1.7; p<0.001; WIHS adjusted-OR, 2.2; 95%CI 1.8-2.7; p<0.001). Chronic obstructive pulmonary disease was more common in MACS HIV-infected vs. HIV-uninfected participants pre-HAART (hazard ratio [adjusted-HR] 2.9; 95%CI, 1.02-8.4; p = 0.046). After HAART availability, non-infectious lung diseases were not significantly more common in HIV-infected participants in either MACS or WIHS participants. HIV-infected participants in the HAART era with respiratory infections had an increased risk of death compared to those without infections (MACS adjusted-HR, 1.5; 95%CI, 1.3-1.7; p<0.001; WIHS adjusted-HR, 1.9; 95%CI, 1.5-2.4; p<0.001). Conclusion: HIV infection remained a significant risk for infectious respiratory diseases after the introduction of HAART, and infectious respiratory diseases were associated with an increased risk of mortality. © 2013 Gingo et al

IL-22 mediates goblet cell hyperplasia and worm expulsion in intestinal helminth infection.

Type 2 immune responses are essential in protection against intestinal helminth infections. In this study we show that IL-22, a cytokine important in defence against bacterial infections in the intestinal tract, is also a critical mediator of anti-helminth immunity. After infection with Nippostrongylus brasiliensis, a rodent hookworm, IL-22-deficient mice showed impaired worm expulsion despite normal levels of type 2 cytokine production. The impaired worm expulsion correlated with reduced goblet cell hyperplasia and reduced expression of goblet cell markers. We further confirmed our findings in a second nematode model, the murine whipworm Trichuris muris. T.muris infected IL-22-deficient mice had a similar phenotype to that seen in N.brasiliensis infection, with impaired worm expulsion and reduced goblet cell hyperplasia. Ex vivo and in vitro analysis demonstrated that IL-22 is able to directly induce the expression of several goblet cell markers, including mucins. Taken together, our findings reveal that IL-22 plays an important role in goblet cell activation, and thus, a key role in anti-helminth immunity

Efficacy of D-cycloserine augmented brief intensive cognitive-behavioural therapy for paediatric obsessive-compulsive disorder: A randomised clinical trial

Objective: To examine the efficacy of weight-adjusted D-cycloserine (DCS) (35 or 70 mg) relative to placebo augmentation of intensive exposure therapy for youth with obsessive-compulsive disorder (OCD) in a double-blind, randomised controlled trial, and examine whether antidepressant medication or patient age moderated outcomes. Methods: Youth (n = 100, 7–17 years) with OCD were randomised in a 1:1 ratio to either DCS + exposure (n = 49) or placebo + exposure (n = 51). Assessments occurred posttreatment, 1 month later, and at 3 and 6 months. Pills were ingested immediately before sessions. Results: Significant improvements on all outcomes were observed at posttreatment, and to 6-month follow-up. Treatment arms did not differ across time, with no significant time-by-medication interactions on symptom severity (T1 to T2 estimate: 9.3, 95% confidence interval [CI]: −11.2 to −7.4, and estimate −10.7, 95% CI: −12.6 to −8.7), diagnostic severity (T1 to T2 estimate: −2.0, 95% CI: −2.4 to −1.5 and estimate −2.5, 95% CI: −3.0 to −2.0) or global functioning (T1 to T2 estimate: 13.8, 95% CI: 10.6 to 17.0, and estimate 16.6, 95% CI: 13.2 to 19.9). Neither antidepressants at baseline nor age moderated primary outcomes. There were significantly fewer responders/remitters at 1- and 6-month follow-up among youth in the DCS condition stabilised on SSRIs, relative to youth not taking SSRIs. Conclusions: DCS augmented intensive exposure therapy did not result in overall additional benefits relative to placebo. Intensive exposure proved effective in reducing symptoms for the overall sample