The ratio of carbon dioxide consumption to oxygen evolution in sea water in the light

The production of organic matter in sea water by the phytoplankton community has frequently been computed (Nielsen, 1937; Riley 1941) by measuring the oxygen evolution in bottled sea water samples and calculating the organic matter on the assumption that the phytoplankton organisms produced glucose by photosynthesis according to the equation:..

Money, (Co)Production and Power in Digital

This article discusses the contribution of critical political economy approaches to digital journalism studies and argues that these offer important correctives to celebratory perspectives. The first part offers a review and critique of influential claims arising from self-styled new studies of convergence culture, media and creative industries. The second part discusses the contribution of critical political economy in examining digital journalism and responding to celebrant claims. The final part reflects on problems of restrictive normativity and other limitations within media political economy perspectives and considers ways in which challenges might be addressed by more synthesising approaches. The paper proposes developing radical pluralist, media systems and comparative analysis, and advocates drawing on strengths in both political economy and culturalist traditions to map and evaluate practices across all sectors of digital journalism

Recreational and occupational field exposure to freshwater cyanobacteria – a review of anecdotal and case reports, epidemiological studies and the challenges for epidemiologic assessment

Cyanobacteria are common inhabitants of freshwater lakes and reservoirs throughout the world. Under favourable conditions, certain cyanobacteria can dominate the phytoplankton within a waterbody and form nuisance blooms. Case reports and anecdotal references dating from 1949 describe a range of illnesses associated with recreational exposure to cyanobacteria: hay fever-like symptoms, pruritic skin rashes and gastro-intestinal symptoms are most frequently reported. Some papers give convincing descriptions of allergic reactions while others describe more serious acute illnesses, with symptoms such as severe headache, pneumonia, fever, myalgia, vertigo and blistering in the mouth. A coroner in the United States found that a teenage boy died as a result of accidentally ingesting a neurotoxic cyanotoxin from a golf course pond. This death is the first recorded human fatality attributed to recreational exposure to cyanobacteria, although uncertainties surround the forensic identification of the suspected cyanotoxin in this case. We systematically reviewed the literature on recreational exposure to freshwater cyanobacteria. Epidemiological data are limited, with six studies conducted since 1990. Statistically significant increases in symptoms were reported in individuals exposed to cyanobacteria compared to unexposed counterparts in two Australian cohort studies, though minor morbidity appeared to be the main finding. The four other small studies (three from the UK, one Australian) did not report any significant association. However, the potential for serious injury or death remains, as freshwater cyanobacteria under bloom conditions are capable of producing potent toxins that cause specific and severe dysfunction to hepatic or central nervous systems. The exposure route for these toxins is oral, from ingestion of recreational water, and possibly by inhalation. A range of freshwater microbial agents may cause acute conditions that present with features that resemble illnesses attributed to contact with cyanobacteria and, conversely, acute illness resulting from exposure to cyanobacteria or cyanotoxins in recreational waters could be misdiagnosed. Accurately assessing exposure to cyanobacteria in recreational waters is difficult and unreliable at present, as specific biomarkers are unavailable. However, diagnosis of cyanobacteria-related illness should be considered for individuals presenting with acute illness following freshwater contact if a description is given of a waterbody visibly affected by planktonic mass development

Prosaccade errors in the antisaccade task: differences between corrected and uncorrected errors and links to neuropsychological tests

The relations among spatial memory, Stroop-like colour-word subtests, and errors on antisaccade and memory-guided saccadic eye-movement trials for older and younger adults were tested. Two types of errors in the antisaccade task were identified: short latency prosaccade errors that were immediately corrected and longer latency uncorrected prosaccade errors. The age groups did not differ on percentages of either corrected or uncorrected errors, but the latency and time to correct prosaccade errors were shorter for younger than older adults. Uncorrected prosaccade errors correlated significantly with spatial memory accuracy and errors on the colour-word subtests, but neither of these neuropsychological indices correlated with corrected prosaccade errors. These findings suggest that uncorrected prosaccade errors may be a result of cognitive factors involving a failure to maintain the goal of the antisaccade task in working memory. In contrast, corrected errors may be a consequence of a fixation system involving an initial failure to inhibit a reflexive prosaccade but with active goal maintenance enabling correction to take place

Mild intraoperative hypothermia during surgery for intracranial aneurysm

BACKGROUND: Surgery for intracranial aneurysm often results in postoperative neurologic deficits. We conducted a randomized trial at 30 centers to determine whether intraoperative cooling during open craniotomy would improve the outcome among patients with acute aneurysmal subarachnoid hemorrhage. METHODS: A total of 1001 patients with a preoperative World Federation of Neurological Surgeons score of I, II, or III ("good-grade patients"), who had had a subarachnoid hemorrhage no more than 14 days before planned surgical aneurysm clipping, were randomly assigned to intraoperative hypothermia (target temperature, 33 degrees C, with the use of surface cooling techniques) or normothermia (target temperature, 36.5 degrees C). Patients were followed closely postoperatively and examined approximately 90 days after surgery, at which time a Glasgow Outcome Score was assigned. RESULTS: There were no significant differences between the group assigned to intraoperative hypothermia and the group assigned to normothermia in the duration of stay in the intensive care unit, the total length of hospitalization, the rates of death at follow-up (6 percent in both groups), or the destination at discharge (home or another hospital, among surviving patients). At the final follow-up, 329 of 499 patients in the hypothermia group had a Glasgow Outcome Score of 1 (good outcome), as compared with 314 of 501 patients in the normothermia group (66 percent vs. 63 percent; odds ratio, 1.14; 95 percent confidence interval, 0.88 to 1.48; P=0.32). Postoperative bacteremia was more common in the hypothermia group than in the normothermia group (5 percent vs. 3 percent, P=0.05). CONCLUSIONS: Intraoperative hypothermia did not improve the neurologic outcome after craniotomy among good-grade patients with aneurysmal subarachnoid hemorrhage

A Photon Counting Imager

The Remote Low Light Imaging (RULLI) system responds to individual photons using a modification to conventional image intensifier technology and fast timing electronics. Each photon received at the detector is resolved in three dimensions (X, Y, and time). The accumulation of photons over time allows the system to image with very low light levels, such as starlight illumination. Using a low power pulsed laser and very fine time discrimination, three dimensional imaging has been accomplished with a vertical resolution of five cm

Demonstration of Literal Three-Dimensional Imaging

In a recent paper a new technique was proposed for remote ranging and topographical mapping by using a system with a single-photon-counting detector and a low-power pulsed laser @Appl. Opt. 35, 441 ~1996!#. We report on the results from the laboratory and the field demonstration of this literal three-dimensional imaging technique. Using a detector system developed at Los Alamos with a commercial pulsed laser and observing from a single remote vantage point, we demonstrate use of this technique in the literal mapping of three-dimensional topography and the probing of a complex scene. With a reasonably short exposure this system can resolve features with height variations as small as 5 cm. © 1999 Optical Society of Americ