School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ, UK. email@example.com
Observations of internal wave velocity fluctuations show that enhanced turbulent mixing over rough topography in the Southern Ocean is remarkably intense and widespread. Mixing rates exceeding background values by a factor of 10 to 1000 are common above complex bathymetry over a distance of 2000 to 3000 kilometers at depths greater than 500 to 1000 meters. This suggests that turbulent mixing in the Southern Ocean may contribute crucially to driving the upward transport of water closing the ocean's meridional overturning circulation, and thus needs to be represented in numerical simulations of the global ocean circulation and the spreading of biogeochemical tracers.
Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA, UK. firstname.lastname@example.org
Although the Antarctic Circumpolar Current (ACC) is the longest and the strongest oceanic current on the Earth and is the primary means of inter-basin exchange, it remains one of the most poorly represented components of global climate models. Accurately describing the circulation of the ACC is made difficult owing to the prominent role that mesoscale eddies and jets, oceanic equivalents of atmospheric storms and storm tracks, have in setting the density structure and transport properties of the current. The successes and limitations of different representations of eddy processes in models of the ACC are considered, with particular attention given to how the circulation responds to changes in wind forcing. The dynamics of energetic eddies and topographically steered jets may both temper and enhance the sensitivity of different aspects of the ACC's circulation to changes in climate.
Variations in behavior and condition of a Southern Ocean top predator in relation to in situ oceanographic conditions.
M Biuw, L Boehme, C Guinet, M Hindell, D Costa, J-B Charrassin, F Roquet, F Bailleul, M Meredith, S Thorpe, Y Tremblay, B McDonald, Y-H Park, S R Rintoul, N Bindoff, M Goebel, D Crocker, P Lovell, J Nicholson, F Monks, M A Fedak
Natural Environment Research Council Sea Mammal Research Unit, Gatty Marine Laboratory, University of St. Andrews, St. Andrews, Fife KY16 8LB, United Kingdom. email@example.com
Responses by marine top predators to environmental variability have previously been almost impossible to observe directly. By using animal-mounted instruments simultaneously recording movements, diving behavior, and in situ oceanographic properties, we studied the behavioral and physiological responses of southern elephant seals to spatial environmental variability throughout their circumpolar range. Improved body condition of seals in the Atlantic sector was associated with Circumpolar Deep Water upwelling regions within the Antarctic Circumpolar Current, whereas High-Salinity Shelf Waters or temperature/salinity gradients under winter pack ice were important in the Indian and Pacific sectors. Energetic consequences of these variations could help explain recently observed population trends, showing the usefulness of this approach in examining the sensitivity of top predators to global and regional-scale climate variability.
Department of Earth and Atmospheric Sciences, Purdue University, West Lafayette, Indiana 47907, USA.
Ocean mixing affects global climate and the marine biosphere because it is linked to the ocean's ability to store and transport heat and nutrients. Observations have constrained the magnitude of upper ocean mixing associated with certain processes, but mixing rates measured directly are significantly lower than those inferred from budget analyses, suggesting that other processes may play an important role. The winds associated with tropical cyclones are known to lead to localized mixing of the upper ocean, but the hypothesis that tropical cyclones are important mixing agents at the global scale has not been tested. Here we calculate the effect of tropical cyclones on surface ocean temperatures by comparing surface temperatures before and after storm passage, and use these results to calculate the vertical mixing induced by tropical cyclone activity. Our results indicate that tropical cyclones are responsible for significant cooling and vertical mixing of the surface ocean in tropical regions. Assuming that all the heat that is mixed downwards is balanced by heat transport towards the poles, we calculate that approximately 15 per cent of peak ocean heat transport may be associated with the vertical mixing induced by tropical cyclones. Furthermore, our analyses show that the magnitude of this mixing is strongly related to sea surface temperature, indicating that future changes in tropical sea surface temperatures may have significant effects on ocean circulation and ocean heat transport that are not currently accounted for in climate models.
School of Ocean and Earth Science, National Oceanography Centre, Southampton SO14 3ZH, UK. firstname.lastname@example.org
The oceanic overturning circulation has a central role in the Earth's climate system and in biogeochemical cycling, as it transports heat, carbon and nutrients around the globe and regulates their storage in the deep ocean. Mixing processes in the Antarctic Circumpolar Current are key to this circulation, because they control the rate at which water sinking at high latitudes returns to the surface in the Southern Ocean. Yet estimates of the rates of these processes and of the upwelling that they induce are poorly constrained by observations. Here we take advantage of a natural tracer-release experiment-an injection of mantle helium from hydrothermal vents into the Circumpolar Current near Drake Passage-to measure the rates of mixing and upwelling in the current's intermediate layers over a sector that spans nearly one-tenth of its circumpolar path. Dispersion of the tracer reveals rapid upwelling along density surfaces and intense mixing across density surfaces, both occurring at rates that are an order of magnitude greater than rates implicit in models of the average Southern Ocean overturning. These findings support the view that deep-water pathways along and across density surfaces intensify and intertwine as the Antarctic Circumpolar Current flows over complex ocean-floor topography, giving rise to a short circuit of the overturning circulation in these regions.
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Tob Control. 2012 Sep 27;: 23019273
A cross-country comparison of secondhand smoke exposure among adults: findings from the Global Adult Tobacco Survey (GATS).
Office on Smoking and Health, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, Atlanta, Georgia, USA.
OBJECTIVE: Exposure to secondhand smoke (SHS) from burning tobacco products causes disease and premature death among non-smoking adults and children. The objective of this study was to determine the nature, extent and demographic correlates of SHS exposure among adults in low- and middle-income countries with a high burden of tobacco use. METHODS: Data were obtained from the Global Adult Tobacco Survey (GATS), a nationally representative household survey of individuals 15 years of age or older. Interviews were conducted during 2008-2010 in Bangladesh, Brazil, China, Egypt, India, Mexico, the Philippines, Poland, Russia, Thailand, Turkey, Ukraine, Uruguay and Vietnam. Descriptive statistics were used to determine the prevalence and correlates of SHS exposure in homes, workplaces, government buildings, restaurants, public transportation and healthcare facilities. RESULTS: Exposure to SHS in the home ranged from 17.3%(Mexico) to 73.1%(Vietnam). Among those who work in an indoor area outside the home, SHS exposure in the workplace ranged from 16.5%(Uruguay) to 63.3%(China). Exposure to SHS ranged from 6.9%(Uruguay) to 72.7%(Egypt) in government buildings, 4.4%(Uruguay) to 88.5%(China) in restaurants, 5.4%(Uruguay) to 79.6%(Egypt) on public transportation, and 3.8%(Uruguay) to 49.2%(Egypt) in healthcare facilities. CONCLUSIONS: A large proportion of adults living in low- and middle-income countries are exposed to SHS in their homes, workplaces, and other public places. Countries can enact and enforce legislation requiring 100% smoke-free public places and workplaces, and can also conduct educational initiatives to reduce SHS exposure in homes.
Am J Public Health. 2012 Sep 20;: 22994278
Current Tobacco Use Among Adults in the United States: Findings From the National Adult Tobacco Survey.
The authors are with the Office on Smoking and Health, National Center for Chronic Disease Prevention and Health Promotion, and Brian A. King is also with the Epidemic Intelligence Service, Division of Applied Sciences, Scientific Education and Professional Development Program Office, Centers for Disease Control and Prevention, Atlanta, GA.
Objectives. We assessed the prevalence and sociodemographic correlates of tobacco use among US adults. Methods. We used data from the 2009-2010 National Adult Tobacco Survey, a national landline and cell phone survey of adults aged 18 years and older, to estimate current use of any tobacco; cigarettes; cigars, cigarillos, or small cigars; chewing tobacco, snuff, or dip; water pipes; snus; and pipes. We stratified estimates by gender, age, race/ethnicity, education, income, sexual orientation, and US state. Results. National prevalence of current use was 25.2% for any tobacco; 19.5% for cigarettes; 6.6% for cigars, cigarillos, or small cigars; 3.4% for chewing tobacco, snuff, or dip; 1.5% for water pipes; 1.4% for snus; and 1.1% for pipes. Tobacco use was greatest among respondents who were male, younger, of non-Hispanic "other" race/ethnicity, less educated, less wealthy, and lesbian, gay, bisexual, or transgender. Prevalence ranged from 14.1%(Utah) to 37.4%(Kentucky). Conclusions. Tobacco use varies by geography and sociodemographic factors, but remains prevalent among US adults. Evidence-based prevention strategies are needed to decrease tobacco use and the health and economic burden of tobacco-related diseases.(Am J Public Health. Published online ahead of print September 20, 2012: e1-e8. doi:10.2105/AJPH.2012.301002).
Nicotine Tob Res. 2012 Aug 27;: 22927687
Flavored Cigar Smoking Among U.S. Adults: Findings From the 2009-2010 National Adult Tobacco Survey.
Corresponding Author: Brian A. King, Ph.D., M.P.H., Office on Smoking and Health, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, 4770 Buford Highway, MS K-50, Atlanta, GA 30341, USA. Telephone: 770-488-5107; Fax: 770-488-5848; E-mail: email@example.com.
INTRODUCTION: Under its authority to regulate tobacco products, the U.S. Food and Drug Administration prohibited certain characterizing flavors in cigarettes in September 2009; however, flavored cigars are still permitted to be manufactured, distributed, and sold. This study assessed the prevalence and correlates of flavored cigar smoking among U.S. adults. METHODS: Data were obtained from the 2009-2010 National Adult Tobacco Survey, a national landline and cell phone survey of adults aged ≥18 years old residing in the 50U.S. states and the District of Columbia. National and state estimates of flavored cigar use were calculated overall and among current cigar smokers; national estimates were calculated by sex, age, race/ethnicity, educational attainment, annual household income, U.S. Census Region, and sexual orientation. RESULTS: The national prevalence of flavored cigar smoking was 2.8%(95% confidence interval [CI]= 2.6%-3.1%; state range: 0.6%-5.7%) and was greater among those who were male, younger in age, non-Hispanic Other race, less educated, less wealthy, and lesbian, gay, bisexual, or transgendered (LGBT). Nationally, the prevalence of flavored cigar use among cigar smokers was 42.9%(95% CI = 40.1%-45.7%; state range: 11.1%-71.6%) and was greater among those who were female, younger in age, Hispanic, non-Hispanic Other race, less educated, less wealthy, and LGBT.Conclusions:More than two fifths of current cigar smokers report using flavored cigars. Disparities in flavored cigar use also exist across states and subpopulations. Efforts to curb flavored cigar smoking have the potential to reduce the prevalence of overall cigar smoking among U.S. adults, particularly among subpopulations with the greatest burden.
Am J Public Health. 2012 Aug 16;: 22897557
At the time of the study, Andrea S. Licht, Brian A. King, Mark J. Travers, Cheryl Rivard, and Andrew J. Hyland were with the Department of Health Behavior, Roswell Park Cancer Institute, Buffalo, NY. Andrea S. Licht is also with the Department of Social and Preventive Medicine, State University of New York at Buffalo, Buffalo.
We assessed factors related to smoke-free policies among a cross-sectional, nationally representative, random-digit-dial sample (landline and cell phone) of US multiunit housing residents (n = 418). Overall, 29% reported living in smoke-free buildings, while 79% reported voluntary smoke-free home rules. Among those with smoke-free home rules, 44% reported secondhand smoke incursions in their unit. Among all respondents, 56% supported smoke-free building policy implementation. These findings suggest that smoke-free building policies are needed to protect multiunit housing residents from secondhand smoke in their homes.(Am J Public Health. Published online ahead of print August 16, 2012: e1-e4. doi:10.2105/AJPH.2012.300717).
Pediatrics. 2012 Mar ;129 (3):446-52 22311992
Office on Smoking and Health, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, Atlanta, GA 30341, USA. firstname.lastname@example.org
OBJECTIVES Exposure to secondhand smoke (SHS) from cigarettes poses a significant health risk to nonsmokers. Among youth, the home is the primary source of SHS. However, little is known about youth exposure to SHS in other nonpublic areas, particularly motor vehicles. METHODS Data were obtained from the 2000, 2002, 2004, 2006, and 2009 waves of the National Youth Tobacco Survey, a nationally representative survey of US students in grades 6 to 12. Trends in SHS exposure in a car were assessed across survey years by school level, gender, and race/ethnicity by using binary logistic regression. RESULTS From 2000 to 2009, the prevalence of SHS exposure in cars declined significantly among both nonsmokers (39.0%-22.8%; trend P <.001) and smokers (82.3%-75.3%; trend P <.001). Among nonsmokers, this decline occurred across all school level, gender, and race/ethnicity subgroups. CONCLUSIONS SHS exposure in cars decreased significantly among US middle and high school students from 2000 to 2009. Nevertheless, in 2009, over one-fifth of nonsmoking students were exposed to SHS in cars. Jurisdictions should expand comprehensive smoke-free policies that prohibit smoking in worksites and public places to also prohibit smoking in motor vehicles occupied by youth.
Socioeconomic variation in the prevalence, introduction, retention, and removal of smoke-free policies among smokers: findings from the International Tobacco Control (ITC) Four Country Survey.
Department of Health Behavior, Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo, NY 14263, USA. email@example.com
Exposure to secondhand smoke causes premature death and disease in non-smokers and indoor smoke-free policies have become increasingly prevalent worldwide. Although socioeconomic disparities have been documented in tobacco use and cessation, the association between socioeconomic status (SES) and smoke-free policies is less well studied. Data were obtained from the 2006 and 2007 Waves of the International Tobacco Control Four Country Survey (ITC-4), a prospective study of nationally representative samples of smokers in Canada, the United States, the United Kingdom, and Australia. Telephone interviews were administered to 8,245 current and former adult smokers from October 2006 to February 2007. Between September 2007 and February 2008, 5,866 respondents were re-interviewed. Self-reported education and annual household income were used to create SES tertiles. Outcomes included the presence, introduction, and removal of smoke-free policies in homes, worksites, bars, and restaurants. Smokers with high ses had increased odds of both having [OR: 1.54, 95% CI: 1.27-2.87] and introducing [OR: 1.49, 95% CI: 1.04-2.13] a total ban on smoking in the home compared to low SES smokers. Continuing smokers with high SES also had decreased odds of removing a total ban [OR: 0.44, 95% CI: 0.26-0.73]. No consistent association was observed between SES and the presence or introduction of bans in worksites, bars, or restaurants. The presence, introduction, and retention of smoke-free homes increases with increasing SES, but no consistent socioeconomic variation exists in the presence or introduction of total smoking bans in worksites, bars, or restaurants. Opportunities exist to reduce SES disparities in smoke-free homes, while the lack of socioeconomic differences in public workplace, bar, and restaurant smoke-free policies suggest these measures are now equitably distributed in these four countries.
Evaluation of an Intervention to Enhance the Delivery of Smoking Cessation Services to Patients with Cancer.
Marie-Helene Gosselin, Martin C Mahoney, K Michael Cummings, Thom R Loree, Maureen Sullivan, Brian A King, Graham Warren, Andrew Hyland
Division of Cancer Prevention and Population Sciences, Department of Health Behavior, Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo, NY, 14263, USA.
We describe a brief staff training program to improve the delivery of tobacco cessation services to patients with head and neck cancers. This study utilized a quasi-experimental design to compare the delivery of smoking cessation components and outcomes among patients exposed to either usual care (UC) or an enhanced cessation (EC) program implemented following a 1-h staff education program. Of the 179 subjects enrolled, 112 were recontacted by phone 1 month after their clinic visit. More patients in EC compared to UC reported that they were asked about their smoking status (94.2% vs. 76.6%, p = 0.01), advised to quit (92.3% vs. 72.3%, p = 0.01), prescribed cessation medications (30.8% vs. 3.3%, p < 0.001), and received a support call (53.8% vs. 11.7%, p < 0.001) at the 1-month follow-up. Quit attempts and quit rates between groups were similar. The EC intervention improved the delivery of cessation services in a busy clinical setting, but this failed to increase cessation rates after 1 month.
Department of Health Behavior, Division of Cancer Prevention and Population Sciences, Roswell Park Cancer Institute, Buffalo, New York 14263, USA.
OBJECTIVE To assess the efficacy of an intervention to encourage the adoption of smoke-free policies among owners and managers of multiunit housing. DESIGN A pretest-posttest quasi-experimental design was employed. PARTICIPANTS The study population included 287 multiunit housing operators (MUHOs) from across New York State who were recruited to complete a baseline survey designed to assess policies about smoking in the housing units that they owned and/or managed. Subjects were surveyed between March and July 2008 (n = 128 intervention, n = 159 control) and recontacted 1 year later to complete a follow-up survey (n = 59 intervention, n = 95 control). INTERVENTION An informational packet on the benefits of implementing a smoke-free policy was mailed to MUHOs in the New York State counties of Erie and Niagara between March and July 2008. For comparison purposes, a sample of MUHOs located outside of Erie and Niagara counties who did not receive the information packet were identified to serve as control subjects. MAIN OUTCOME MEASURES Logistic regression was used to assess predictors of policy interest, concern, and implementation at follow-up. Predictors included: intervention group, baseline status, respondent smoking status, survey type, government-subsidy status, quantity of units operated, and average building size, construction type, and age. RESULTS Multiunit housing operators who received the information packet were more likely to report interest in adopting a smoke-free policy (OR = 6.49, 95% CI = 1.44-29.2), and less likely to report concerns about adopting such a policy (OR = 0.16, 95% CI = 0.04-0.66) compared to MUHOs who did not receive the information packet; however, the rate of adoption of smoke-free policies was comparable between the groups. CONCLUSION Sending MUHOs an information packet on the benefits of adopting a smoke-free policy was effective in addressing concerns and generating interest toward smoke-free policies but was not sufficient in itself to generate actual policy adoption.
Department of Health Behavior, Division of Cancer Prevention and Population Sciences, Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo, NY 14263, USA. firstname.lastname@example.org
INTRODUCTION Secondhand smoke (SHS) causes significant disease and death. A person's home represents a prominent source of SHS, and the potential for exposure is elevated among those who live in close proximity to smokers in multiunit housing (MUH). This study assessed the prevalence and predictors of SHS exposure and smoke-free policy support among MUH residents. METHODS Data were obtained from 5,936 MUH residents who participated in the New York State Adult Tobacco Survey between May 2007 and May 2009. Bivariate analyses were used to assess the prevalence of smoke-free home policies, SHS incursions, and support for smoke-free policies. Logistic regression was used to identify predictors of these measures while adjusting for gender, age, ethnicity, education, region, children in household, and housing type. RESULTS A total of 73.1% of respondents reported a personal smoke-free home policy in their home. Among these individuals, 46.2% indicated that SHS has ever entered their home in the past year, while 9.2% reported daily incursions. Overall, a majority of respondents (55.6%) support a policy that bans smoking in all areas of their building, including residential units; support was significantly higher among ethnic minorities and individuals who reside with children. DISCUSSION Nearly half of New York MUH residents with a smoke-free home policy have experienced a SHS incursion in their home. Since a majority of MUH residents support smoke-free policies and nearly three quarters already prohibit smoking in their home, opportunities exist for initiatives to promote smoke-free building policies.
Prevalence and predictors of smoke-free policy implementation and support among owners and managers of multiunit housing.
Department of Health Behavior, Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo, NY 14263, USA. email@example.com
INTRODUCTION Exposure to secondhand smoke causes disease and premature death. Although many municipalities have instituted policies prohibiting smoking in public areas, personal living areas remain largely unregulated. Individuals who reside in multiunit housing (MUH) facilities where smoking is permitted are particularly susceptible to involuntary exposure. This study assessed the prevalence and predictors of smoke-free policy implementation and support among owners and managers of MUH throughout Western New York State. METHODS A telephone survey was administered to a sample of owners and managers of MUH buildings in the Erie and Niagara counties, New York. A total of 127 respondents completed the survey between March and July 2008 (62% response rate). Logistic regression was used to assess predictors of policy implementation and support, while adjusting for participant smoking status, quantity of units owned/managed, government subsidy status, as well as building age, construction type, and size. RESULTS Only 13% of participants reported smoking restrictions within any of their buildings. Among those without a smoke-free policy, 75% would be interested in restricting smoking in at least one of their units, with interest being significantly higher among participants with government-subsidized units (odds ratio = 3.12, 95% CI = 1.14-8.52). Primary barriers to policy implementation included concern over increased vacancy (27%) and a decreased market base (21%). DISCUSSION Few Western New York MUH owners and managers have implemented smoke-free policies in their buildings, but most are receptive to doing so. Therefore, opportunities exist for interventions to enhance policy acceptance, implementation, and enforcement among these individuals.
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Ann Rev Mar Sci. 2012 ;4 :317-43 22457978
Department of Physical Oceanography, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA. firstname.lastname@example.org
The inner continental shelf, which spans water depths ofa few meters to tens of meters, is a dynamically defined region that lies between the surf zone (where waves break) and the middle continental shelf (where the along-shelf circulation is usually in geostrophic balance). Many types of forcing that are often neglected over the deeper shelf-such as tides, buoyant plumes, surface gravitywaves, and cross-shelfwind stress-drive substantial circulations over the inner shelf. Cross-shelf circulation over the inner shelf has ecological and geophysical consequences: It connects the shore to the open ocean by transporting pollutants, larvae, phytoplankton, nutrients, and sediment. This review of circulation and momentum balances over the inner continental shelf contrasts prior studies, which focused mainly on the roles of along-shelfwind and pressure gradients, with recent understanding of the dominant roles of cross-shelf wind and surface gravity waves.
Ann Rev Mar Sci. 2011 ;3 :173-95 21329203
Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, Florida 33149, USA. email@example.com
An advantage of using chlorofluorocarbons (CFCs) and sulfur hexafluoride (SF6) as tracers of ocean circulation is that the time-dependent source functions permit calculation of rates for ocean processes. These compounds are also sensitive indicators highlighting interior ocean regions where surface-derived anomalies can be transported on timescales of decades. Significant applications for CFCs have been for the deep limb of the Atlantic meridional overturning circulation, upper ocean ventilation, and biogeochemical rates, including apparent oxygen utilization rates and anthropogenic CO2 inventories. Although CFCs have started to decrease in the atmosphere, SF6 continues to increase. There are benefits to measuring both CFCs and SF6: A large global CFC data set exists; CFCs are still increasing in older waters; SF6 expands estimates of age; and calculations of anthropogenic CO2 inventory are enhanced. Thus, the outlook for using CFCs as tracers for oceanic processes, and in particular in concert with SF6, remains very positive.
Shuhei Masuda, Toshiyuki Awaji, Nozomi Sugiura, John Philip Matthews, Takahiro Toyoda, Yoshimi Kawai, Toshimasa Doi, Shinya Kouketsu, Hiromichi Igarashi, Katsuro Katsumata, Hiroshi Uchida, Takeshi Kawano, Masao Fukasawa
Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokohama 236-0001, Japan. firstname.lastname@example.org
Recent observational surveys have shown significant oceanic bottom-water warming. However, the mechanisms causing such warming remain poorly understood, and their time scales are uncertain. Here, we report computer simulations that reveal a fast teleconnection between changes in the surface air-sea heat flux off the Adélie Coast of Antarctica and the bottom-water warming in the North Pacific. In contrast to conventional estimates of a multicentennial time scale, this link is established over only four decades through the action of internal waves. Changes in the heat content of the deep ocean are thus far more sensitive to the air-sea thermal interchanges than previously considered. Our findings require a reassessment of the role of the Southern Ocean in determining the impact of atmospheric warming on deep oceanic waters.
University of Nevada, Reno, 5625 Fox Avenue, Reno, Nevada 89506, USA. email@example.com
The first measurement of the threshold for thermal ionization of the surface of thick metal by pulsed magnetic field (B) is reported. Thick aluminum-with depth greater than the magnetic skin layer-was pulsed with partial differential B/ partial differential t from 30-80 MG/micros. Novel loads avoided nonthermal plasma (from electron avalanche, or energetic particles or photons from arcs). Thermal plasma forms from 6061-alloy aluminum when the surface magnetic field reaches 2.2 MG, in qualitative agreement with numerical simulation results by Garanin et al.[J. Appl. Mech. Tech. Phys. 46, 153 (2005)].
Department of Electrical Engineering, University of California-Los Angeles,Los Angeles, California 90095-1594, USA.
In silicon devices, the spectral bandwidth of coherent anti-Stokes Raman scattering (CARS) is limited by the narrowband nature of the Raman process in this medium. In this Letter, we report the observation of broadband wavelength conversion in silicon through CARS enhanced by the self-phase-modulation-induced spectral broadening of the optical pump. The CARS conversion over a bandwidth substantially greater than the intrinsic Raman linewidth is demonstrated yielding conversion efficiencies as high as 1%. Numerical simulations are performed to explain the spectral features observed in the spectrum of the anti-Stokes signal.
Internal waves generated by tidal currents concentrated and transported an oil spill (liquid asphalt) onshore. Plankton net samples were collected in front of and behind a set of internal waves as well as in the convergence and divergence zones over the waves. Tar "balls" were most abundant (greater than 30-fold) in the samples from the convergence zone. Comparison of the abundance of tar balls in front of and behind the set of waves suggests that the internal waves "caught" about 68% of the asphalt encountered and concentrated and swept shoreward tar balls from almost 8 kilometers of ocean.
A layer of water at a depth of 200 meters containing 3 to 12 milligrams per liter of oil was found during February and March 1978 over a distance of 800 nautical miles in the southwest North Atlantic and the eastern Caribbean. The geochemistry and carbon-14 activity of the oil shows it to be a weathered crude, probably from a submarine seep. Although the dimensions of the oily layer were not determined, conservative estimates indicate that more than I megaton could have been present.
High-speed movies of splash formation caused by waterdrop impact at terminal velocity in thin water layers show that splash size increases with drop size. For increasing water depth, splash size increases to a maximum at a depth of one-third drop diameter; splash size then decreases to a constant size for depths greater than three drop diameters.
Nature. 2007 Aug 9;448 (7154):680-3 17687321
Department of Oceanography, Florida State University, Tallahassee, Florida 32306, USA. firstname.lastname@example.org
Buoyancy exchange between the deep and the upper ocean, which is essential for maintaining global ocean circulation, mainly occurs through turbulent mixing. This mixing is thought to result primarily from instability of the oceanic internal wave field, but internal waves tend to radiate energy away from the regions in which they are generated rather than dissipate it locally as turbulence and the resulting distribution of turbulent mixing remains unknown. Another, more direct, mixing mechanism involves the generation of turbulence as strong flows pass through narrow passages in topography, but the amount of turbulence generated at such locations remains poorly quantified owing to a lack of direct measurements. Here we present observations from the crest of the Mid-Atlantic Ridge in the subtropical North Atlantic Ocean that suggest that passages in rift valleys and ridge-flank canyons provide the most energetic sites for oceanic turbulence. Our measurements show that diffusivities as large as 0.03 m2 s(-1) characterize the mixing downstream of a sill in a well-stratified boundary layer, with mixing levels remaining of the order of 10(-4) m2 s(-1) at the base of the main thermocline. These mixing rates are significantly higher than the diffusivities of the order of 10(-5) m2 s(-1) that characterize much of the global thermocline and the abyssal ocean. Our estimates suggest that overflows associated with narrow passages on the Mid-Atlantic Ridge in the North Atlantic Ocean produce as much buoyancy flux as has previously been estimated for the entire Romanche fracture zone, a large strait in the Mid-Atlantic Ridge that connects the North and South Atlantic basins. This flux is equivalent to the interior mixing that occurs in the entire North Atlantic basin at the depth of the passages, suggesting that turbulence generated in narrow passages on mid-ocean ridges may be important for buoyancy flux at the global scale.
Department of Physics, Oakland University, Rochester, Michigan, USA.
Experiments using optical mapping suggest that electroporation occurs in cardiac tissue when the transmembrane potential, Vm, is observed to be significantly less than +/- 400 mV. Our hypothesis, which we test by numerical simulation, is that Vm is greater than +/- 400 mV at the tissue surface, but optical mapping underestimates Vm because it averages over depth. Results indicate a significant underestimation of Vm. Experimental studies indicate a depolarization of the resting transmembrane potential, Vrest, after a strong shock. In a homogeneous model, electroporation only occurs near the tissue surface. Just as Vm during the stimulus is underestimated due to averaging, we hypothesize that the depolarization of Vrest is also underestimated.