Deep Near-Infrared Observations of L1014: Revealing the nature of the core and its embedded source

Recently, the Spitzer Space Telescope discovered L1014-IRS, a mid-infrared source with protostellar colors, toward the heretofore "starless" core L1014. We present deep near-infrared observations that show a scattered light nebula extending from L1014-IRS. This nebula resembles those typically associated with protostars and young stellar objects, tracing envelope cavities presumably evacuated by an outflow. The northern lobe of the nebula has an opening angle of ~100 degrees, while the southern lobe is barely detected. Its morphology suggests that the bipolar cavity and inferred protostellar disk is not inclined more than 30 degrees from an edge-on orientation. The nebula extends at least 8" from the source at Ks, strongly suggesting that L1014-IRS is embedded within L1014 at a distance of 200 pc rather than in a more distant cloud associated with the Perseus arm at 2.6 kpc. In this case, the apparently low luminosity of L1014-IRS, 0.090 Lsun, is consistent with it having a substellar mass. However, if L1014-IRS is obscured by a circumstellar disk, its luminosity and inferred mass may be greater. Using near-infrared colors of background stars, we investigate characteristics of the L1014 molecular cloud core. We determine a mass of 3.6 Msun for regions of the core with Av > 2 magnitudes. A comparison of the radial extinction profile of L1014 with other cores suggests that L1014 may be among the most centrally condensed cores known, perhaps indicative of the earliest stages of brown dwarf or star formation processes.Comment: Replacement includes revision to mass of core. 22 pages, 6 figures. Accepted by Ap

A Comparison of Measured Creatinine Clearance versus Calculated Glomerular Filtration Rate for Assessment of Renal Function before Autologous and Allogeneic BMT

AbstractCommon blood and marrow transplantation (BMT) eligibility criteria include a minimum glomerular filtration rate (GFR) that may vary by regimen intensity. GFR is often estimated by measurement of creatinine clearance in a 24-hour urine collection (24-hr CrCl), an inconvenient and error-prone method that overestimates GFR. The study objectives were to determine which of 6 GFR calculations: Cockroft-Gault (CG), modified CG (mCG), Modification of Diet in Renal Disease 1 (MDRD1), MDRD2, Jelliffe, and Wright, consistently underestimated measured 24-hr CrCl pre-BMT. We retrospectively analyzed 98 consecutive allogeneic (n = 48) or autologous (n = 50) adult BMT patients from January 2006 to April 2007. All 6 formulas were significantly (P < .001) correlated with 24-hr CrCl with R = 0.64 (Wright), 0.63 (CG), 0.61 (mCG), 0.61 (Jelliffe), 0.54 (MDRD2), and 0.50 (MDRD1). When compared to the measured 24-hr CrCl, MDRD2 consistently underestimated it in the highest proportion of patients (66%, P < .001), compared with MDRD1 (65%, P < .001), Jelliffe (61%, P = NS), mCG (55%, P = NS), Wright (34%, P < .001), and CG (34%, P = .001). Measured 24-hr CrCl, pre-BMT serum Cr, and all 6 equations were not predictive of renal regimen-related toxicity (RRT) post-BMT. The Wright and CG formulas are closest to, but overestimate 24-hr CrCl in 66% of patients. In comparison, MDRD2 consistently underestimates 24-hr CrCl in 66%. Although MDRD2 is the most conservative formula, all 6 formulas gave reasonable estimates of GFR and any of the 6 equations can replace the measured 24-hr CrCl. Larger analyses and transplantation of patients with GFR <50 mL/min may better define subgroups at risk for renal RRT

Common Genetic Variants Are Associated with Accelerated Bone Mineral Density Loss after Hematopoietic Cell Transplantation

BACKGROUND: Bone mineral density (BMD) loss commonly occurs after hematopoietic cell transplantation (HCT). Hypothesizing that genetic variants may influence post-HCT BMD loss, we conducted a prospective study to examine the associations of single nucleotide polymorphisms (SNP) in bone metabolism pathways and acute BMD loss after HCT. METHODS AND FINDINGS: We genotyped 122 SNPs in 45 genes in bone metabolism pathways among 121 autologous and allogeneic HCT patients. BMD changes from pre-HCT to day +100 post-HCT were analyzed in relation to these SNPs in linear regression models. After controlling for clinical risk factors, we identified 16 SNPs associated with spinal or femoral BMD loss following HCT, three of which have been previously implicated in genome-wide association studies of bone phenotypes, including rs2075555 in COL1A1, rs9594738 in RANKL, and rs4870044 in ESR1. When multiple SNPs were considered simultaneously, they explained 5-35% of the variance in post-HCT BMD loss. There was a significant trend between the number of risk alleles and the magnitude of BMD loss, with patients carrying the most risk alleles having the greatest loss. CONCLUSION: Our data provide the first evidence that common genetic variants play an important role in BMD loss among HCT patients similar to age-related BMD loss in the general population. This infers that the mechanism for post-HCT bone loss is a normal aging process that is accelerated during HCT. A limitation of our study comes from its small patient population; hence future larger studies are warranted to validate our findings

The Role of Cytotoxic Therapy with Hematopoietic Stem Cell Transplantation in the Therapy of Acute Lymphoblastic Leukemia in Adults: An Evidence-based Review

AbstractEvidence supporting the role of hematopoietic stem cell transplantation (SCT) in the therapy of acute lymphoblastic leukemia in adults (≥15 years) is presented and critically evaluated in this systematic evidence-based review. Specific criteria were used for searching the published medical literature and for grading the quality and strength of the evidence, and the strength of the treatment recommendations. Treatment recommendations based on the evidence are presented and were reached unanimously by a panel of acute lymphoblastic leukemia experts. The priority areas of needed future research for adult acute lymphoblastic leukemia are: definition of patients at high risk in first complete remission, beyond Philadelphia chromosome positive; outcomes of SCT in older (>50 years) adults; determination if reduced intensity versus myeloablative conditioning regimens yield an equivalent graft-versus-leukemia effect with reduced toxicity; monitoring of minimal residual disease to achieve disease control before SCT; and the use of cord blood and other alternative sources of stem cells for use in adult SCT recipients

Controls on Ice Cliff Distribution and Characteristics on Debris-Covered Glaciers

Ice cliff distribution plays a major role in determining the melt of debris-covered glaciers but its controls are largely unknown. We assembled a data set of 37,537 ice cliffs and determined their characteristics across 86 debris-covered glaciers within High Mountain Asia (HMA). We find that 38.9% of the cliffs are stream-influenced, 19.5% pond-influenced and 19.7% are crevasse-originated. Surface velocity is the main predictor of cliff distribution at both local and glacier scale, indicating its dependence on the dynamic state and hence evolution stage of debris-covered glacier tongues. Supraglacial ponds contribute to maintaining cliffs in areas of thicker debris, but this is only possible if water accumulates at the surface. Overall, total cliff density decreases exponentially with debris thickness as soon as the debris layer reaches a thickness of over 10 cm

Analysis of detector performance in a gigahertz clock rate quantum key distribution system

We present a detailed analysis of a gigahertz clock rate environmentally robust phase-encoded quantum key distribution (QKD) system utilizing several different single-photon detectors, including the first implementation of an experimental resonant cavity thin-junction silicon single-photon avalanche diode. The system operates at a wavelength of 850 nm using standard telecommunications optical fibre. A general-purpose theoretical model for the performance of QKD systems is presented with reference to these experimental results before predictions are made about realistic detector developments in this system. We discuss, with reference to the theoretical model, how detector operating parameters can be further optimized to maximize key exchange rates