Particle Dynamics in the Rising Plume at Piccard Hydrothermal Field, Mid-Cayman Rise

Processes active in rising hydrothermal plumes, such as precipitation, particle aggregation, and biological growth, affect particle size distributions and can exert important influences on the biogeochemical impact of submarine venting of iron to the oceans and their sediments. However, observations to date of particle size distribution within these systems are both limited and conflicting. In a novel buoyant hydrothermal plume study at the recently discovered high-temperature (398°C) Piccard Hydrothermal Field, Mid-Cayman Rise, we report optical measurements of particle size distributions (PSDs). We describe the plume PSD in terms of a simple, power-law model commonly used in studies of upper and coastal ocean particle dynamics. Observed PSD slopes, derived from spectral beam attenuation and laser diffraction measurements, are among the highest found to date anywhere in the ocean and ranged from 2.9 to 8.5. Beam attenuation at 650 nm ranged from near zero to a rarely observed maximum of 192 m-1 at 3.5 m above the vent. We did not find large (\u3e100 µm) particles that would settle rapidly to the sediments. Instead, beam attenuation was well-correlated to total iron, suggesting the first-order importance of particle dilution, rather than precipitation or dissolution, in the rising plume at Piccard. Our observations at Piccard caution against the assumption of rapid deposition of hydrothermal, particulate metal fluxes, and illustrate the need for more particle size and composition measurements across a broader range of sites, globally

Regional distribution of nosocomial infections due to ESBL-positive Enterobacteriaceae in Germany: data from the German National Reference Center for the Surveillance of Nosocomial Infections (KISS)

AbstractSurveillance systems for hospital infections are reporting increasing rates of extended-spectrum β-lactamase (ESBL)-positive Enterobacteriaceae in Europe. We aimed to perform a national survey on this trend and on the regional distribution of nosocomial infections due to ESBL-positive Enterobacteriaceae in German hospitals. Data from 2007 to 2012 from two components of the German national nosocomial infection surveillance system were used for this analysis. The data derive from intensive care units and surgical departments. Independent factors determining the proportion of ESBL-positive Enterobacteriaceae among nosocomial infections due to Enterobacteriaceae and changes in its regional distribution (broken down into German federal states) were calculated by regression analysis. From 2007 to 2012, the data showed a significantly increasing proportion of ESBL-positive Enterobacteriaceae in surgical site infections (from 11.46 to 15.38, 134%, p 0.003), urinary tract infections (9.36 to 16.56, 177%, p <0.001) and lower respiratory tract infections (11.91 to 14.70, 123%, p <0.001) due to Enterobacteriaceae. Factors independently associated with a growing proportion were: Thuringia (p 0.009; odds ratio (OR) 1.53), North Rhine-Westphalia (p <0.001; OR 1.41) and general surgery ward (p 0.002; OR 1.47). The proportion of ESBL-positive Enterobacteriaceae in nosocomial infections has significantly increased in Germany over the last 6 years. Hospitals in Central Germany and surgical departments in all of Germany are especially affected by this development

Mineral phase analysis of deep-sea hydrothermal particulates by a Raman spectroscopy expert algorithm : toward autonomous in situ experimentation and exploration

Author Posting. © American Geophysical Union, 2009. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 10 (2009): Q05T05, doi:10.1029/2008GC002314.This paper demonstrates that a Raman spectroscopy, point-counting technique can be used for phase analysis of minerals commonly found in deep-sea hydrothermal plumes, even for minerals with similar chemical compositions. It also presents our robust autonomous identification algorithm and spectral database, both of which were developed specifically for deep-sea hydrothermal studies. The Raman spectroscopy expert algorithm was developed and tested against multicomponent mixtures of minerals relevant to the deep-sea hydrothermal environment. It is intended for autonomous classification where many spectra must be examined with little or no human involvement to increase analytic precision, accuracy, and data volume or to enable in situ measurements and experimentation.Support for J.A.B. was provided through a RIDGE 2000 Postdoctoral Fellowship (NSF OCE-0550331)

PSYCHOSIS IN HINDSIGHT: A COLLECTIVE RECOLLECTION OF THE ONSET OF PSYCHOSIS

poster abstractPsychotic disorders cause marked cognitive, perceptual, and social impairments and may lead to significant disability. Those affected with these illnesses may have great difficulty in educational, occupational, and social functioning; especially troubling is the fact that these illness often strike when those afflicted should be entering into some of the most productive years of their lives. The primary purpose of this study is to ascertain the perspective of subjects with psychotic disorders on the mental health system and treatment, stigmatization, social functioning, and symptom experience. This information will be of use in improving treatment engagement, compliance, and education of providers. Fifty subjects with nonaffective psychoses in each of two arms (new onset psychosis and chronic psychosis) will be enrolled and asked to complete a self-administered questionnaire. After subjects complete the questionnaire, investigators will review medical records to confirm subject age and diagnosis, compare subject report with symptomatology, and look for trends or topics of interest in comparing patient survey reports with medical records which may provide for useful insight upon further investigation

Emergence of phytoplankton patchiness at small scales in mild turbulence

Phytoplankton often encounter turbulence in their habitat. As most toxic phytoplankton species are motile, resolving the interplay of motility and turbulence has fundamental repercussions on our understanding of their own ecology and of the entire ecosystems they inhabit. The spatial distribution of motile phytoplankton cells exhibits patchiness at distances of decimeter to millimeter scale for numerous species with different motility strategies. The explanation of this general phenomenon remains challenging. Furthermore, hydrodynamic cell-cell interactions, which grow more relevant as the density in the patches increases, have been so far ignored. Here, we combine particle simulations and continuum theory to study the emergence of patchiness in motile microorganisms in three dimensions. By addressing the combined effects of motility, cell-cell interaction and turbulent flow conditions, we uncover a general mechanism: the coupling of cell-cell interactions to the turbulent dynamics favors the formation of dense patches. Identification of the important length and time scales, independently from the motility mode, allows us to elucidate a general physical mechanism underpinning the emergence of patchiness. Our results shed light on the dynamical characteristics necessary for the formation of patchiness, and complement current efforts to unravel planktonic ecological interactions

Particle dynamics in the rising plume at Piccard Hydrothermal Field, Mid-Cayman Rise

Author Posting. © American Geophysical Union, 2015. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry, Geophysics, Geosystems 16 (2015): 2762–2774, doi:10.1002/2015GC005831.Processes active in rising hydrothermal plumes, such as precipitation, particle aggregation, and biological growth, affect particle size distributions and can exert important influences on the biogeochemical impact of submarine venting of iron to the oceans and their sediments. However, observations to date of particle size distribution within these systems are both limited and conflicting. In a novel buoyant hydrothermal plume study at the recently discovered high-temperature (398°C) Piccard Hydrothermal Field, Mid-Cayman Rise, we report optical measurements of particle size distributions (PSDs). We describe the plume PSD in terms of a simple, power-law model commonly used in studies of upper and coastal ocean particle dynamics. Observed PSD slopes, derived from spectral beam attenuation and laser diffraction measurements, are among the highest found to date anywhere in the ocean and ranged from 2.9 to 8.5. Beam attenuation at 650 nm ranged from near zero to a rarely observed maximum of 192 m−1 at 3.5 m above the vent. We did not find large (>100 μm) particles that would settle rapidly to the sediments. Instead, beam attenuation was well-correlated to total iron, suggesting the first-order importance of particle dilution, rather than precipitation or dissolution, in the rising plume at Piccard. Our observations at Piccard caution against the assumption of rapid deposition of hydrothermal, particulate metal fluxes, and illustrate the need for more particle size and composition measurements across a broader range of sites, globally.This work was funded by the National Science Foundation (OCE-1029223; OCE-1061863), NASA (NNX09AB75G) and Woods Hole Oceanographic Institution's Deep Ocean Exploration Institute and Ocean Ridge Initiative. Ship time (R/V Falkor cruise FK008) was funded by the Schmidt Ocean Institute and M.L.E. was supported by a WHOI Postdoctoral Scholar fellowship.2016-02-2

Investigations of Aerobic Methane Oxidation in Two Marine Seep Environments: Part 2—Isotopic Kinetics

During aerobic oxidation of methane (CH4) in seawater, a process which mitigates atmospheric emissions, the 12C‐isotopologue reacts with a slightly greater rate constant than the 13C‐isotopologue, leaving the residual CH4 isotopically fractionated. Prior studies have attempted to exploit this systematic isotopic fractionation from methane oxidation to quantify the extent that a CH4 pool has been oxidized in seawater. However, cultivation‐based studies have suggested that isotopic fractionation fundamentally changes as a microbial population blooms in response to an influx of reactive substrates. Using a systematic mesocosm incubation study with recently collected seawater, here we investigate the fundamental isotopic kinetics of aerobic CH4 oxidation during a microbial bloom. As detailed in a companion paper, seawater samples were collected from seep fields in Hudson Canyon, U.S. Atlantic Margin, and atop Woolsey Mound (also known as Sleeping Dragon) which is part of lease block MC118 in the northern Gulf of Mexico, and used in these investigations. The results from both Hudson Canyon and MC118 show that in these natural environments isotopic fraction for CH4 oxidation follows a first‐order kinetic process. The results also show that the isotopic fractionation factor remains constant during this methanotrophic bloom once rapid CH4 oxidation begins and that the magnitude of the fractionation factor appears correlated with the first‐order reaction rate constant. These findings greatly simplify the use of natural stable isotope changes in CH4 to assess the extent that CH4 is oxidized in seawater following seafloor release

Investigations of Aerobic Methane Oxidation in Two Marine Seep Environments: Part 1—Chemical Kinetics

Microbial aerobic oxidation is known to be a significant sink of marine methane (CH4), contributing to the relatively minor atmospheric release of this greenhouse gas over vast stretches of the ocean. However, the chemical kinetics of aerobic CH4 oxidation are not well established, making it difficult to predict and assess the extent that CH4 is oxidized in seawater following seafloor release. Here we investigate the kinetics of aerobic CH4 oxidation using mesocosm incubations of fresh seawater samples collected from seep fields in Hudson Canyon, U.S. Atlantic Margin and MC118, Gulf of Mexico to gain a fundamental chemical understanding of this CH4 sink. The goals of this investigation were to determine the response or lag time following CH4 release until more rapid oxidation begins, the reaction order, and the stoichiometry of reactants utilized (i.e., CH4, oxygen, nitrate, phosphate, trace metals) during CH4 oxidation. The results for both Hudson Canyon and MC118 environments show that CH4 oxidation rates sharply increased within less than one month following the CH4 inoculation of seawater. However, the exact temporal characteristics of this more rapid CH4 oxidation varied based on location, possibly dependent on the local circulation and biogeochemical conditions at the point of seawater collection. The data further suggest that methane oxidation behaves as a first‐order kinetic process and that the reaction rate constant remains constant once rapid CH4 oxidation begins

Time course of improvement with antipsychotic medication in treatment-resistant schizophrenia

Background Improvements are greatest in the earlier weeks of antipsychotic treatment of patients with non-resistant schizophrenia. Aims To address the early time-line for improvement with antipsychotics in treatment-resistant schizophrenia. Method Randomised double-blind trials of antipsychotic medication in adult patients with treatment-resistant schizophrenia were investigated (last search June 2010). A series of meta-regression analyses were carried out to examine the effect of time on the average item scores in the Positive and Negative Syndrome Scale (PANSS) or Brief Psychiatric Rating Scale (BPRS) at three or more distinct time points within the first 6 weeks of treatment. Results Study duration varied from 4 weeks to 1 year and the definitions of treatment resistance as well as of treatment response were not necessarily consistent across 19 identified studies, resulting in highly variable rates of response (0–76%). The mean standardised baseline item score in the PANSS or BPRS was 3.4 (s.e. = 0.06) in the five studies included in the meta-regression analysis, with the average baseline Clinical Global Impression – Severity score being 5.2 (marked illness). For the pooled population treated with a range of antipsychotics (n = 1019), significant reductions in the mean item scores occurred during the first 4 weeks; improvements observed in later weeks were smaller and non-significant. In contrast, weekly improvement with clozapine was significant throughout (n = 356). Conclusions Our findings provide preliminary evidence that the majority of improvement with antipsychotics may occur relatively early. More consistent improvements with clozapine may be associated with a gradual titration. To further elucidate response patterns, future studies are needed to provide data over regular intervals during earlier stages of treatment.peer-reviewe

Functional neuroanatomical correlates of episodic memory impairment in early phase psychosis

Studies have demonstrated that episodic memory (EM) is often preferentially disrupted in schizophrenia. The neural substrates that mediate EM impairment in this illness are not fully understood. Several functional magnetic resonance imaging (fMRI) studies have employed EM probe tasks to elucidate the neural underpinnings of impairment, though results have been inconsistent. The majority of EM imaging studies have been conducted in chronic forms of schizophrenia with relatively few studies in early phase patients. Early phase schizophrenia studies are important because they may provide information regarding when EM deficits occur and address potential confounds more frequently observed in chronic populations. In this study, we assessed brain activation during the performance of visual scene encoding and recognition fMRI tasks in patients with earlyphase psychosis (n = 35) and age, sex, and race matched healthy control subjects (n = 20). Patients demonstrated significantly lower activation than controls in the right hippocampus and left fusiform gyrus during scene encoding and lower activation in the posterior cingulate, precuneus, and left middle temporal cortex during recognition of target scenes. Symptom levels were not related to the imaging findings, though better cognitive performance in patients was associated with greater right hippocampal activation during encoding. These results provide evidence of altered function in neuroanatomical circuitry subserving EM early in the course of psychotic illness, which may have implications for pathophysiological models of this illness