Discovery of Resolved Debris Disk Around HD 131835

We report the discovery of the resolved disk around HD 131835 and present the analysis and modeling of its thermal emission. HD 131835 is a ~15 Myr A2 star in the Scorpius-Centaurus OB association at a distance of 122.7 +16.2 -12.8 parsec. The extended disk has been detected to ~1.5" (200 AU) at 11.7 {\mu}m and 18.3 {\mu}m with T-ReCS on Gemini South. The disk is inclined at an angle of ~75{\deg} with the position angle of ~61{\deg}. The flux of HD 131835 system is 49.3+-7.6 mJy and 84+-45 mJy at 11.7 {\mu}m and 18.3 {\mu}m respectively. A model with three grain populations gives a satisfactory fit to both the spectral energy distribution and the images simultaneously. This best-fit model is composed of a hot continuous power-law disk and two rings. We characterized the grain temperature profile and found that the grains in all three populations are emitting at temperatures higher than blackbodies. In particular, the grains in the continuous disk are unusually warm; even when considering small graphite particles as the composition.Comment: 11 pages, 5 figures, Accepted for Publication in Ap

Travelers’ diarrhea and other gastrointestinal symptoms among Boston-area international travelers

INTRODUCTION: Travelers' diarrhea (TD) and non-TD gastrointestinal (GI) symptoms are common among international travelers. In a study of short-term travelers from Switzerland to developing countries, the most common symptom experienced was severe diarrhea (8.5%) followed by vomiting or abdominal cramps (4%).1 GI illnesses were the most frequently reported diagnoses (34%) among ill-returned travelers to GeoSentinel clinics.2 Of those returning to U.S. GeoSentinel clinics, acute diarrhea (30%) was the most common diagnosis.3 In one cohort of U.S. travelers, 46% reported diarrhea.4 GI illnesses can last from 2 days to weeks or longer,5 disrupting plans during travel or after returning home. Eighty percent of those who experienced diarrhea during travel treated themselves with medication and 6% sought medical care. METHODS: The Boston Area Travel Medicine Network (BATMN) is a research collaboration of travel clinics in the greater Boston area representing urban-, suburban-, academic-, and university-affiliated facilities. A convenience sample of travelers ≥ 18 years of age attending three BATMN clinics between 2009 and 2011 for pre-travel consultations completed pre-travel surveys, at least one survey weekly during travel, and a post-travel survey 2–4 weeks after return. Travelers were asked to complete a survey at the end of each week of their trip. Institutional review board approvals were obtained at all sites and the Centers for Disease Control and Prevention, and participants provided written informed consent. Information collected included demographic and trip characteristics, vaccines and medications recommended/prescribed before travel, medications taken during travel, dietary practices during travel (consumption of tap water, ice in drinks, unpasteurized dairy products, and salads), symptoms experienced, and impact of illness during and after travel. Vaccinations, prescriptions, and travel health advice given during the pre-travel consultation were recorded by a clinician, and the remainder of the surveys were completed by the traveler. Data were entered into a password-protected database (CS Pro, U.S. Census Bureau, Washington, DC). RESULTS: We enrolled 987 travelers; 628 (64%) completed all three parts (pre-, during, and post-travel) and were included in the study. Comparison of the 628 to the 359 who did not complete all three parts (noncompleters) revealed no differences, except that completion rates were higher for white travelers than all other racial/ethnic groups (P < 0.001) and for older travelers (median age 47 years versus 32 years in noncompleters, P < 0.001).11 Of those 628 travelers, 208 (33%) experienced TD, 45 (7%) experienced non-TD GI symptoms, 147 (23%) experienced non-GI symptoms, and 228 (36%) did not experience any symptoms during or after travel. Of the 208 with TD, 140 (67%) reported diarrhea as their only symptom, whereas 33 (16%) also experienced nausea/vomiting, 23 (11%) abdominal pain, and 27 (13%) fever (Table 1). Of the 45 who reported non-TD GI symptoms, 21 (47%) experienced nausea/vomiting, 19 (42%) experienced constipation, and 10 (22%) experienced abdominal pain during or after travel (Table 2). Almost all travelers (99%) received advice about food and water precautions and diarrhea management during pre-travel consultation

Quantum Hacking: Experimental demonstration of time-shift attack against practical quantum key distribution systems

Quantum key distribution (QKD) systems can send signals over more than 100 km standard optical fiber and are widely believed to be secure. Here, we show experimentally for the first time a technologically feasible attack, namely the time-shift attack, against a commercial QKD system. Our result shows that, contrary to popular belief, an eavesdropper, Eve, has a non-negligible probability (~4%) to break the security of the system. Eve's success is due to the well-known detection efficiency loophole in the experimental testing of Bell inequalities. Therefore, the detection efficiency loophole plays a key role not only in fundamental physics, but also in technological applications such as QKD.Comment: 5 pages, 3 figures. Substantially revised versio

Self-reported illness among Boston-area international travelers: A prospective study

This is the Accepted Manuscript version and was published in final edited form as: Travel Med Infect Dis. 2016 ; 14(6): 604–613. doi:10.1016/j.tmaid.2016.09.009.BACKGROUND: The Boston Area Travel Medicine Network surveyed travelers on travel-related health problems. METHODS: Travelers were recruited 2009-2011 during pre-travel consultation at three clinics. The investigation included pre-travel data, weekly during-travel diaries, and a post-travel questionnaire. We analyzed demographics, trip characteristics, health problems experienced, and assessed the relationship between influenza vaccination, influenza prevention advice, and respiratory symptoms. RESULTS:Of 987 enrolled travelers, 628 (64%) completed all surveys, of which 400 (64%) reported health problems during and/or after travel; median trip duration was 12 days. Diarrhea affected the most people during travel (172) while runny/stuffy nose affected the most people after travel (95). Of those with health problems during travel, 25% stopped or altered plans; 1% were hospitalized. After travel, 21% stopped planned activities, 23% sought physician or other health advice; one traveler was hospitalized. Travelers who received influenza vaccination and influenza prevention advice had lower rates of respiratory symptoms than those that received influenza prevention advice alone (18% vs 28%, P = 0.03). CONCLUSIONS:A large proportion of Boston-area travelers reported health problems despite pre-travel consultation, resulting in inconveniences. The combination of influenza prevention advice and influenza immunization was associated with fewer respiratory symptoms than those who received influenza prevention advice alone

The Exozodiacal Dust Problem for Direct Observations of ExoEarths

Debris dust in the habitable zones of stars - otherwise known as exozodiacal dust - comes from extrasolar asteroids and comets and is thus an expected part of a planetary system. Background flux from the Solar System's zodiacal dust and the exozodiacal dust in the target system is likely to be the largest source of astrophysical noise in direct observations of terrestrial planets in the habitable zones of nearby stars. Furthermore, dust structures like clumps, thought to be produced by dynamical interactions with exoplanets, are a possible source of confusion. In this paper, we qualitatively assess the primary impact of exozodical dust on high-contrast direct imaging at optical wavelengths, such as would be performed with a coronagraph. Then we present the sensitivity of previous, current, and near-term facilities to thermal emission from debris dust at all distances from nearby solar-type stars, as well as our current knowledge of dust levels from recent surveys. Finally, we address the other method of detecting debris dust, through high-contrast imaging in scattered light. This method is currently far less sensitive than thermal emission observations, but provides high spatial resolution for studying dust structures. This paper represents the first report of NASA's Exoplanet Exploration Program Analysis Group (ExoPAG).Comment: 21 pages, 5 figures, 2 tables. Accepted for publication in PASP 2012-06-0

The effects of acute experimental hip muscle pain on dynamic single-limb balance performance in healthy middle-aged adults

Middle-aged adults with painful hip conditions show balance impairments that are consistent with an increased risk of falls. Pathological changes at the hip, accompanied by pain, may accelerate pre-existing age-related balance deficits present in midlife. To consider the influence of pain alone, we investigated the effects of acute experimental hip muscle pain on dynamic single-limb balance in middle-aged adults. Thirty-four healthy adults aged 40–60 years formed two groups (Group-1: n\ua0=\ua016; Group-2: n\ua0=\ua018). Participants performed four tasks: Reactive Sideways Stepping (ReactSide); Star Excursion Balance Test (SEBT); Step Test; Single-Limb Squat; before and after an injection of hypertonic saline into the right gluteus medius muscle (Group-1) or ∼5\ua0min rest (Group-2). Balance measures included the range and standard deviation of centre of pressure (CoP) movement in mediolateral and anterior-posterior directions, and CoP total path velocity (ReactSide, Squat); reach distance (SEBT); and number of completed steps (Step Test). Data were assessed using three-way analysis of variance. Motor outcomes were altered during the second repetition of tasks irrespective of exposure to experimental hip muscle pain or rest, with reduced SEBT anterior reach (−1.2\ua0±\ua04.1\ua0cm, P\ua0=\ua00.027); greater step number during Step Test (1.5\ua0±\ua01.7 steps, P\ua