Isolation and characterization of thermophilic, calcium-precipitating bacteria form calcite deposits at Yucca Mountain

Calcite deposits, composed of a mixture of calcium carbonate and silicon dioxide, were found in fractures and small cavities within the welded tuff of Yucca Mountain. This research investigation involves determining the presence of thermophilic, calciumprecipitating bacteria within these deposits. The possible existence of thermophilic bacteria may help to resolve the issue of whether these calcite deposits formed from precipitation of dissolved calcium carbonate in rain water transported from the overlying soil environment or as a result of upwelling of geothermally-heated waters transported from below the mountain. Evidence for microbially-influenced calcite precipitation in these deposits is indicated by the presence of moderately-thermophilic, calciumprecipitating bacteria. Growth of bacteria enriched from crushed calcite and calcite/tuff mixed samples collected from tunnels within Yucca Mountain indicate a tendency for thermophiles to be found in calcite deposits and mixed rock samples compared to tuff samples (no calcite) which lacked bacterial growth at temperatures of 50° C and higher. Calcite isolates growing at 60 and 70° C were identified as thermophiles, the most common identification being Bacillus stearothermophilus. SEM and electron dispersion spectroscopy (EDS) results showed that bacteria, isolated from Yucca Mountain calcite and calcite/tuff, produced calcite (CaCO3) when grown on calcium-enriched medium. This evidence indicates a possible warm water influence in the history of Yucca Mountain

Contrast Adaptation Contributes to Contrast-Invariance of Orientation Tuning of Primate V1 Cells

BACKGROUND: Studies in rodents and carnivores have shown that orientation tuning width of single neurons does not change when stimulus contrast is modified. However, in these studies, stimuli were presented for a relatively long duration (e. g., 4 seconds), making it possible that contrast adaptation contributed to contrast-invariance of orientation tuning. Our first purpose was to determine, in marmoset area V1, whether orientation tuning is still contrast-invariant with the stimulation duration is comparable to that of a visual fixation. METHODOLOGY/PRINCIPAL FINDINGS: We performed extracellular recordings and examined orientation tuning of single-units using static sine-wave gratings that were flashed for 200 msec. Sixteen orientations and three contrast levels, representing low, medium and high values in the range of effective contrasts for each neuron, were randomly intermixed. Contrast adaptation being a slow phenomenon, cells did not have enough time to adapt to each contrast individually. With this stimulation protocol, we found that the tuning width obtained at intermediate contrast was reduced to 89% (median), and that at low contrast to 76%, of that obtained at high contrast. Therefore, when probed with briefly flashed stimuli, orientation tuning is not contrast-invariant in marmoset V1. Our second purpose was to determine whether contrast adaptation contributes to contrast-invariance of orientation tuning. Stationary gratings were presented, as previously, for 200 msec with randomly varying orientations, but the contrast was kept constant within stimulation blocks lasting >20 sec, allowing for adaptation to the single contrast in use. In these conditions, tuning widths obtained at low contrast were still significantly less than at high contrast (median 85%). However, tuning widths obtained with medium and high contrast stimuli no longer differed significantly. CONCLUSIONS/SIGNIFICANCE: Orientation tuning does not appear to be contrast-invariant when briefly flashed stimuli vary in both contrast and orientation, but contrast adaptation partially restores contrast-invariance of orientation tuning

A statewide approach to systematising hand hygiene behaviour in hospitals : clean hands save lives, part I

OBJECTIVE: To describe the planning and execution of a statewide campaign aimed at improving compliance with hand hygiene practices in New South Wales public hospitals. DESIGN AND SETTING: The campaign was conducted in all area health services (AHSs) in NSW (covering 208 public hospitals) between February 2006 and February 2007. Clinical practice improvement methods and campaign strategies were used to improve the availability and use of alcohol-based hand rub (AHR) at the point of patient care, using staff champions and local leaders, engaging patients and families, and measuring compliance. Staff were given regular feedback on their performance. Project officers funded by the Clinical Excellence Commission (CEC) provided local project management support and implemented the campaign in a standardised format orchestrated by the CEC. MAIN OUTCOME MEASURES: Proportion of available beds with secured and unsecured AHR containers nearby; amount of AHR used (based on purchasing patterns). RESULTS: Hospital visits before the campaign identified a lack of appropriately placed AHR at the point of care. The number of AHR containers per available bed in near-patient locations increased to 13 280/18 951 (70%) after the campaign. The quantity of AHR purchased per month across NSW public hospitals increased from 1477 L to 5568 L (a 377% increase). CONCLUSION: The CEC was successful in systematising the placement of AHR in all NSW public hospitals at the point of patient care. Although the use of AHR increased substantially, some staff were resistant to changing their hand hygiene practices.5 page(s

Improvements in hand hygiene across New South Wales public hospitals : clean hands save lives, part III

OBJECTIVE: To describe improvements in hand hygiene compliance after a statewide hand hygiene campaign conducted in New South Wales public hospitals. DESIGN AND SETTING: The campaign was conducted in all area health services in NSW (covering all 208 public hospitals). Alcohol-based hand rub (AHR) was introduced into all hospitals between March and June 2006. In each hospital, five overt observation surveys of hand hygiene compliance by health care workers (HCWs) were conducted: one pre-implementation survey and four post-implementation surveys (in August 2006, November 2006, February 2007 and July 2008). MAIN OUTCOME MEASURES: Overtly observed hand hygiene compliance rates by HCWs, stratified by before- and after-patient contact, Fulkerson's contact risk categories, and four health care professional groupings. RESULTS: The overall hand hygiene compliance rate improved from 47% before the intervention to an average of 61% over the last three observation periods (P < 0.001). All professional groups sustained improved compliance rates except medical staff, whose practices reverted to pre-intervention rates. Nursing staff maintained significantly improved compliance, with an average rate of 67% after the intervention. Overall hand hygiene compliance before patient contact improved from 39% (pre-campaign) to 52% (July 2008) (P < 0.001). Overall compliance after patient contact improved from 57% to 64% (P < 0.001) over the same period. Compliance associated with medium-risk contacts increased from an average of 51% in the first two observation periods to an average of 62% over the last three observation periods (P < 0.001). The corresponding compliance rates associated with low-risk contacts were 35% and 56%, respectively (P < 0.001). CONCLUSION: An overall improvement in hand hygiene rates was achieved with the introduction of AHR. Increased adherence to before-patient contact compliance, especially by nursing staff, contributed to the progress made, but an acceptable overall level of hand hygiene practice is yet to be achieved. It is now time to focus on a long-term behavioural change program directed specifically at medical staff.7 page(s