Significance of streambed sediments as a reservoir of Cryptosporidium Oocysts (The)

The identification of the sources and mechanisms for the fate and transport ofCryptosporidium is important to its control by water suppliers and public health officials. This study examines the role that sediments have in concentrating and resuspending Cryptosporidium oocysts in the environment and its potential impact on water column concentrations. To investigate these aspects of sediment, a new analytical method was successfully developed in this study to isolate and recover Cryptosporidium oocysts from sediment matrices. The new method observed recoveries within the requirements for all ranges established in USEPA Method 1623. A field study was also performed to characterize the presence and concentrations of Cryptosporidium oocysts in local streambed sediments. Cryptosporidium oocysts were detected in the sediments at a frequency similar to that observed in the water column (33%). Comparing the mean concentrations in the sediment and in the water column, concentrations of Giardia and Cryptosporidium in the sediment were 80 and 147 times greater than in the water column respectively. The equivalent median concentration of Cryptosporidium in sediment was statistically greater than that in the water column during the study period. Streambed sediment resuspension was estimated to comprise from 4% to 27% of the total Cryptosporidium flux for the Wissahickon Creek depending upon the depth of sediment resuspended and the range of concentrations in the sediment and water column. It was also estimated that resuspension of the top 1 to inches of sediment could increase concentrations in a standing water body (lake or reservoir) by a factor of ten. Based on these findings, sediment has the potential to play a significant role in any watershed as a significant source and sink of Cryptosporidium oocysts and therefore must be factoredinto most, if not all, watershed management and public health strategies. The most effective approach may include employing combined strategies focused on reduction or treatment of elevated levels of Cryptosporidium from constant discharge sources, overland sources, or sediment loading and bed load transport in a manner that is complimentary to existing programs designed to address other contaminants and balanced against cost effectiveness measures.Ph.D., Environmental Engineering -- Drexel University, 200

Obstructive Sleep Apnea Syndrome in Children with 22q11.2 Deletion Syndrome after Operative Intervention for Velopharyngeal Insufficiency

Introduction: Surgical treatment of velopharyngeal insufficiency (VPI) in 22q11.2 deletion syndrome is often warranted. In this patient population, VPI is characterized by poor palatal elevation and muscular hypotonia with an intact palate. We hypothesize that 22q11.2 deletion patients are at greater risk of obstructive sleep apnea (OSA) after surgical correction of VPI, due, in part, to their functional hypotonia, large velopharyngeal gap size, and the need to surgically obstruct the velopharynx. Methods: We performed a retrospective analysis of patients with 22q11.2 deletion syndrome treated at a tertiary pediatric hospital between the years of 2002-2012. The incidence of VPI, need for surgery, post-operative polysomnogram, post-operative VPI assessment, and OSA treatments were evaluated. Results: Forty-three patients (18 males, 25 females, ages 1-14 years) fitting the inclusion criteria were identified. Twenty-eight patients were evaluated by speech pathology due to hypernasality. Twenty-one patients had insufficient velopharyngeal function and required surgery. Fifteen underwent pharyngeal flap surgery, three underwent sphincter pharyngoplasty, two underwent Furlow palatoplasty, and one underwent combined sphincter pharyngoplasty with Furlow palatoplasty. Of these, eight had post-operative snoring. Six of these underwent polysomnography. Four patients were found to have OSA based on the results of the polysomnography (average apnea/hypopnea index of 4.9 events/hour, median=5.1, SD=2.1). Two required continuous positive airway pressure (CPAP) due to moderate OSA.Conclusion: Surgery is often necessary to correct VPI in patients with 22q11.2 deletion syndrome. Monitoring for OSA should be considered after surgical correction of VPI due to a high occurrence in this population. Furthermore, families should be counseled of the risk of OSA after surgery and the potential need for treatment with CPAP

Starspot-induced optical and infrared radial velocity variability in T Tauri star Hubble 4

We report optical (6150 Ang) and K-band (2.3 micron) radial velocities obtained over two years for the pre-main sequence weak-lined T Tauri star Hubble I 4. We detect periodic and near-sinusoidal radial velocity variations at both wavelengths, with a semi-amplitude of 1395\pm94 m/s in the optical and 365\pm80 m/s in the infrared. The lower velocity amplitude at the longer wavelength, combined with bisector analysis and spot modeling, indicates that there are large, cool spots on the stellar surface that are causing the radial velocity modulation. The radial velocities maintain phase coherence over hundreds of days suggesting that the starspots are long-lived. This is one of the first active stars where the spot-induced velocity modulation has been resolved in the infrared.Comment: Accepted for publication in The Astrophysical Journa

CSO and CARMA Observations of L1157. I. A Deep Search for Hydroxylamine (NH2_2OH)

A deep search for the potential glycine precursor hydroxylamine (NH$_2$OH) using the Caltech Submillimeter Observatory (CSO) at $\lambda = 1.3$ mm and the Combined Array for Research in Millimeter-wave Astronomy (CARMA) at $\lambda = 3$ mm is presented toward the molecular outflow L1157, targeting the B1 and B2 shocked regions. We report non-detections of NH$_2$OH in both sources. We a perform non-LTE analysis of CH$_3$OH observed in our CSO spectra to derive kinetic temperatures and densities in the shocked regions. Using these parameters, we derive upper limit column densities of NH$_2$OH of $\leq1.4 \times 10^{13}$~cm$^{-2}$ and $\leq1.5 \times 10^{13}$~cm$^{-2}$ toward the B1 and B2 shocks, respectively, and upper limit relative abundances of $N_{NH_2OH}/N_{H_2} \leq1.4 \times 10^{-8}$ and $\leq1.5 \times 10^{-8}$, respectively.Comment: Accepted in the Astrophysical Journa

A Candidate Young Massive Planet in Orbit around the Classical T Tauri Star CI Tau

The ~2 Myr old classical T Tauri star CI Tau shows periodic variability in its radial velocity (RV) variations measured at infrared (IR) and optical wavelengths. We find that these observations are consistent with a massive planet in a ~9-day period orbit. These results are based on 71 IR RV measurements of this system obtained over 5 years, and on 26 optical RV measurements obtained over 9 years. CI Tau was also observed photometrically in the optical on 34 nights over ~one month in 2012. The optical RV data alone are inadequate to identify an orbital period, likely the result of star spot and activity induced noise for this relatively small dataset. The infrared RV measurements reveal significant periodicity at ~9 days. In addition, the full set of optical and IR RV measurements taken together phase coherently and with equal amplitudes to the ~9 day period. Periodic radial velocity signals can in principle be produced by cool spots, hot spots, and reflection of the stellar spectrum off the inner disk, in addition to resulting from a planetary companion. We have considered each of these and find the planet hypothesis most consistent with the data. The radial velocity amplitude yields an Msin(i) of ~8.1 M_Jup; in conjunction with a 1.3 mm continuum emission measurement of the circumstellar disk inclination from the literature, we find a planet mass of ~11.3 M_Jup, assuming alignment of the planetary orbit with the disk.Comment: 61 pages, 13 figures, accepted for publication in The Astrophysical Journa

The birth place of the type Ic Supernova 2007gr

We report our attempts to locate the progenitor of the peculiar type Ic SN 2007gr in HST pre-explosion images of the host galaxy, NGC 1058. Aligning adaptive optics Altair/NIRI imaging of SN 2007gr from the Gemini (North) Telescope with the pre-explosion HST WFPC2 images, we identify the SN position on the HST frames with an accuracy of 20 mas. Although nothing is detected at the SN position we show that it lies on the edge of a bright source, 134+/-23 mas (6.9 pc) from its nominal centre. Based on its luminosity we suggest that this object is possibly an unresolved, compact and coeval cluster and that the SN progenitor was a cluster member, although we note that model profile fitting favours a single bright star. We find two solutions for the age of this assumed cluster; 7-/+0.5 Myrs and 20-30 Myrs, with turn-off masses of 28+/-4 Msun and 12-9 Msun respectively. Pre-explosion ground-based K-band images marginally favour the younger cluster age/higher turn-off mass. Assuming the SN progenitor was a cluster member, the turn-off mass provides the best estimate for its initial mass. More detailed observations, after the SN has faded, should determine if the progenitor was indeed part of a cluster, and if so allow an age estimate to within ~2 Myrs thereby favouring either a high mass single star or lower mass interacting binary progenitor.Comment: 12 pages, 3 figures, resolution of fig 1. has been reduced, some revision based on referee's comments, Accepted ApJL 27 Nov 200

Is environmental radon gas associated with the incidence of neurodegenerative conditions? A retrospective study of multiple sclerosis in radon affected areas in England and Wales

To test whether an association exists between radon gas concentration in the home and increased multiple sclerosis (MS) incidence, a retrospective study was undertaken of MS incidence in known areas of raised domestic radon concentration in England and Wales, using The Health Improvement Network (THIN) clinical research database.The study population comprised 20,140,498 person-years of clinical monitoring (males: 10,056,628: 49.93%; females: 10,083,870: 50.07%), representing a mean annual population of 2.5 million individuals. To allow for the possible latency of MS initiation following exposure, data extraction was limited to patients with at least five years registration history with the same GP practice before first diagnosis. Patient records were allocated to one of nine radon concentration bands depending on the average radon level in their postcode sector.MS incidence was analysed by searching for patients with first MS diagnosis over the eight calendar years 2005-2012 inclusive. 1512 new MS cases were diagnosed, 1070 females, 442 males, equivalent to raw incidence rates of 7.51, 10.61 and 4.40 per 105person-years respectively, comparable to previously reported results. Of these new cases, 115 could be allocated to one of the radon bands representing high radon areas.Standardising to the UK 2010 population, excess relative risk (ERR) figures for MS were calculated for each radon band. Linear regression of ERR against mean band radon concentration shows a positive gradient of 0.22 per 100 Bq·m-3(R2= 0.25, p = 0.0961) when forced through the origin to represent a linear-no-threshold response. The null hypothesis falls inside the 95% confidence interval for the linear fit and therefore this fit is not statistically significant. We conclude that, despite THIN sampling around 5% of the population, insufficient data was available to confirm or refute the hypothesised association between MS incidence and radon concentration

An assessment of the effectiveness of UK building regulations for new homes in Radon Affected Areas

Radon, a naturally occurring radioactive gas generated underground by radioactive decay of nuclides contained in certain types of rocks, can concentrate inside buildings, where it poses the second-largest risk factor for lung cancer, after smoking. The highest concentrations of domestic radon in the UK occur in the south-western counties of Devon and Cornwall, but certain areas in Northamptonshire and surrounding counties in the English Midlands also have high levels. It has been shown that it is possible both to reduce the radon concentrations in existing houses and to build new homes with appropriate protection. Since 1999, the UK's Building Regulations have specified that all new homes should be built with a combined radon-proof/damp-proof membrane plus, in Radon Affected Areas, a sump under the building. However, the building regulations do not require that the radon level is measured once the house is built and so there is little information on the effectiveness of these measures. Builders generally do not mention radon, and when asked, just confirm that their houses are built to current standards. To better understand the efficacy or otherwise of the currently mandated radon-protection measures, a cross-sectional investigation was carried out in 26 new housing developments in high-radon areas in Northamptonshire. In a targeted mail-shot, 1056 householders were invited to apply for a free radon test; 124 replied (11.7%). In total, 94 pairs of detectors were returned (70.1% of responders), of which two were spoiled, giving a total of 92 results. Following processing and seasonal correction, the arithmetic mean radon concentration in the target houses was 45% of the arithmetic mean radon concentration in existing houses in the postcode sectors where the houses were built and were approximately log-normally distributed. No results exceeded the UK Action Level of 200 Bq. m−3 but three were above the Target Level of 100 Bq. m−3. The results suggest that the radon-proof membranes in general ensure that radon concentrations in new homes constructed in accordance with the Building Regulations in Radon Affected Areas (RAAs) are satisfactorily low. However, there is a very small statistical probability that levels in a small number of homes will be close to or above the Action Level, particularly in areas of high radon potential. As a result, the Public Health England (PHE) recommendation for testing in the first year of occupation should be adopted as a legal requirement