A laser diode based system for calibration of fast time-of-flight detectors

A system based on commercially available items, such as a laser diode, emitting in the visible range $\sim 400$ nm,and multimode fiber patches, fused fiber splitters and optical switches may be assembled,for time calibration of multi-channels time-of-flight (TOF) detectors with photomultipliers' (PMTs') readout. As available laser diode sources have unfortunately limited peak power, the main experimental problem is the tight light power budget of such a system. In addition, while the technology for fused fiber splitters is common in the Telecom wavelength range ($\lambda \sim 850, 1300-1500$ nm), it is not easily available in the visible one. Therefore, extensive laboratory tests had to be done on purpose, to qualify the used optical components, and a full scale timing calibration prototype was built. Obtained results show that with such a system, a calibration resolution ($\sigma$) in the range 20-30 ps may be within reach. Therefore, fast multi-channels TOF detectors, with timing resolutions in the range 50-100 ps, may be easily calibrated in time. Results on tested optical components may be of interest also for time calibration of different light detection systems based on PMTs, as the ones used for detection of the vacuum ultraviolet scintillation light emitted by ionizing particles in large LAr TPCs.Comment: submitted to JINS

Proton Pump Inhibitors and Corticosteroids as Synergistic Risk Factors for Candida Esophagitis

Abstract: Introduction: Inhaled & systemic steroids are one of the well-documented risks factors for Candida esophagitis. However, the role of gastric acid suppression remains controversial. Methods: We conducted a retrospective case-control study of 420 patients consisting of 84 cases of Candida esophagitis and 336 matched controls. Our cohort was gathered from subjects evaluated from 2001 to 2012. The diagnosis of Candida esophagitis was based on endoscopic and/or histological criteria. Results: On univariate analysis, proton pump inhibitors were associated with higher risk (OR = 2.14; 95 % CI: 1.30 to 3.54); steroid use also increased the risk (OR = 3.55; 95% CI: 2.10 to 6.00). Furthermore, concurrent use of proton pump inhibitors & steroids substantially raised this risk (OR = 13.8; 95% CI 5.07 to 37.5), suggesting a synergistic effect. When adjusted for covariates (cancer, chemotherapy/radiation, antibiotic use, hypothyroidism, anemia, chronic liver disease & diabetes), anemia decreased the odds ratio for proton pump inhibitors to 1.67 (95% CI 1.02 to 2.75) and steroids to 1.69 (95% CI to 1.03 to 2.87). Hypothyroidism also substantially reduced the observed risk associated with steroid use. However, neither anemia nor hypothyroidism reduced the odds ratio for combined use of steroids and proton pump inhibitors. Conclusions: Our data suggests that patients who have been treated with steroids or proton pump inhibitors are at an increased risk for developing Candida esophagitis. Our data also suggests that steroids and proton pump inhibitors act synergistically to greatly increase the likelihood of Candida esophagitis

Role of Non-Selective Beta Blockers in Hepatocellular Carcinoma: An Analysis in Patients with Cirrhosis and Portal Hypertension

There are many different biochemical processes responsible for the hepatocelluar carcinoma (HCC) development that can be targeted for the prevention or halt progression of the HCC. Non-selective betablockers (NSBB) affects a multitude of intracellular biochemical and signaling pathways involved in carcinogenesis. Aim: To determine if NSBB may be protective for HCC in patients with cirrhosis and portal hypertension. Methods: We retrospectively enrolled 200 patients from medical records diagnosed with cirrhosis and portal hypertension between January 2001 and December 2013. Eighteen patients were excluded (taking selective beta-blocker and/or unavailable medical records). The etiology of cirrhosis, use of NSBB, demographics and the presence of HCC was collected. Result: There were 140 males and 42 females. The mean age for portal hypertension with cirrhosis without HCC was 53.5 ± 11.4 & with HCC was 62.2 ± 9.5 years. Univariate analysis of the association of NSBB with HCC yielded OR = 0. 11 (95% CI: 0.04 to 0.25); p \u3c 0.0001, suggesting a protective effect of NSBB. Multivariable analysis suggests virtually no change when the Odds ratio (OR) was adjusted for diabetes mellitus (DM), alcohol use, Hepatitis B virus (HBV) status, Black race and age ≥ 53. There was a slight increase in the OR adjusted for statin use. Conclusion: This study highlights association of NSBB use in the patients with liver cirrhosis and portal hypertension for prevention of HCC

Serum magnesium levels and acute exacerbation of chronic obstructive pulmonary disease: a retrospective study

A decrease in serum Mg+ 2 is associated with airway hyper-reactivity and impaired pulmonary function. The purpose of this study was to determine if decreased serum Mg+ 2 levels in patients with chronic obstructive pulmonary disease (COPD) are associated with acute exacerbations. In a retrospective study, the charted serum Mg+ 2 levels in 100 COPD patients were examined. These included 50 patients who presented with an acute exacerbation of COPD and 50 stable patients. Chart review was sequential within both groups. Serum Mg 2+ levels in the stable COPD patients averaged 0.91±0.10 mmol/L (mean±SD) with a 95% CI of 0.88–0.94 mmol/L. Patients undergoing an exacerbation had significantly lower serum Mg+ 2 levels (0.77±0.10 mmol/L; CI, 0.74–0.79; p< 0.0001). Logistic regression of the dichotomous outcomes as a function of serum Mg+ 2 concentration demonstrated a highly significant

Building Arc Crust: Plutonic to Volcanic Connections in an Extensional Oceanic Arc, the Southern Alisitos Arc, Baja California

The ~50 km long Rosario segment of the Cretaceous Alisitos oceanic arc terrane provides undeformed three-dimensional exposures of the upper 7 km of an oceanic extensional arc, where crustal generation processes are recorded in both the volcanic and underlying plutonic rocks. These exceptional exposures allow for the study of the physical and chemical links between the rock units and help constrain the differentiation processes active during the growth and evolution of arc crust. This study focuses on the southern third of the Rosario segment, previously referred to as the southern volcano-bounded basin, and its plutonic underpinnings. Upper crustal rocks in the Rosario segment consist of a 3–5 km thick volcanic–volcaniclastic section with hypabyssal intrusions. Plutons intrude these units at various levels along-strike, but at each intrusive contact the transition is complete over a distance of \u3c150 \u3em, where stoped volcanic blocks are present. There is striking compositional overlap in whole-rock and mineral chemistry between the plutonic and volcanic units, suggesting a comagmatic source. Whole-rock geochemistry shows coherent trends in major and trace elements in mafic to intermediate compositions, but less coherent trends above 63 wt % SiO2. Units are predominantly low-K with flat rare earth element patterns, and show large ion lithophile element enrichment and high field strength element depletion. Initial Nd and Pb isotope ratios overlap for all units and imply no cratonic continental involvement. This agrees with low Sr/Y ratios of all rock types, indicative of thin, immature oceanic arc crust. Modeling results show that closed-system fractional crystallization drove crustal differentiation from mafic to intermediate compositions, but open-system processes likely occurred to produce some of the felsic compositions. Differentiation occurred in a two-step fractionation process. Step 1, from basaltic andesite to andesite, fractionated an anhydrous gabbroic cumulate (~40% crystallization). Step 2, from andesite to rhyolite, fractionated a hydrous amphibole cumulate (~65% crystallization, total), which is similar to what fluid dynamical models suggest for production of rhyolite (between 50 – 70% crystallization). Our results can be used as a reference model for differentiation processes relating to the growth of the middle and upper crust within active extensional arc systems. The Rosario segment plutonic rocks may be analogous to the low-velocity zone (Vp = 6.0–6.5 km s–1) imaged within the extensional Izu–Bonin arc. The chemistry of the plutonic and volcanic rocks is most similar to those of volcanic rocks in the Izu–Bonin active rift

Arc-continent collision: The making of an orogen

Peer Reviewe

Hazardous explosive eruptions of a recharging multi-cyclic island arc caldera

Caldera-forming eruptions of silicic volcanic systems are among the most devastating events on Earth. By contrast, post-collapse volcanic activity initiating new caldera cycles is generally considered less hazardous. Formed after Santorini’s latest caldera-forming eruption of ~1600 bce, the Kameni Volcano in the southern Aegean Sea enables the eruptive evolution of a recharging multi-cyclic caldera to be reconstructed. Santorini’s eruptive record has been documented by onshore products and historical descriptions of mainly effusive eruptions dating back to 197 bce. Here we combine high-resolution seismic reflection data with cored lithologies from International Ocean Discovery Program Expedition 398 at four sites to determine the submarine architecture and volcanic history of intra-caldera deposits from Kameni. Our shore-crossing analysis reveals the deposits of a submarine explosive eruption that produced up to 3.1 km3 of pumice and ash, which we relate to a historical eruption in 726 ce. The estimated volcanic explosivity index of magnitude 5 exceeds previously considered worst-case eruptive scenarios for Santorini. Our finding that the Santorini caldera is capable of producing large explosive eruptions at an early stage in the caldera cycle implies an elevated hazard potential for the eastern Mediterranean region, and potentially for other recharging silicic calderas

Expedition 350 methods

Introduction This chapter of the International Ocean Discovery Program (IODP) Expedition 350 Proceedings volume documents the procedures and tools employed in the various shipboard laboratories of the R/V JOIDES Resolution during Expedition 350. This information applies only to shipboard work described in the Expedition Reports section of this volume. Methods for shore-based analyses of Expedition 350 samples and data will be described in the individual scientific contributions to be published in the open literature or in the Expedition Research Results section of this volume. This section describes procedures and equipment used for drilling, coring, and hole completion; core handling; computation of depth for samples and measurements; and sequence of shipboard analyses. Subsequent sections describe specific laboratory procedures and instruments in more details