Internal gravity waves, the subsurface analogue of the familiar surface gravity waves that break on beaches, are ubiquitous in the ocean. Because of their strong vertical and horizontal currents, and ...the turbulent mixing caused by their breaking, they affect a panoply of ocean processes, such as the supply of nutrients for photosynthesis, sediment and pollutant transport and acoustic transmission; they also pose hazards for man-made structures in the ocean. Generated primarily by the wind and the tides, internal waves can travel thousands of kilometres from their sources before breaking, making it challenging to observe them and to include them in numerical climate models, which are sensitive to their effects. For over a decade, studies have targeted the South China Sea, where the oceans' most powerful known internal waves are generated in the Luzon Strait and steepen dramatically as they propagate west. Confusion has persisted regarding their mechanism of generation, variability and energy budget, however, owing to the lack of in situ data from the Luzon Strait, where extreme flow conditions make measurements difficult. Here we use new observations and numerical models to (1) show that the waves begin as sinusoidal disturbances rather than arising from sharp hydraulic phenomena, (2) reveal the existence of .200- metre-high breaking internal waves in the region of generation that give rise to turbulence levels .10,000 times that in the open ocean, (3) determine that the Kuroshio western boundary current noticeably refracts the internal wave field emanating from the Luzon Strait, and (4) demonstrate a factor-of-two agreement between modelled and observed energy fluxes, which allows us to produce an observationally supported energy budget of the region. Together, these findings give a cradle-to-grave picture of internal waves on a basin scale, which will support further improvements of their representation in numerical climate predictions.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK
DM Broda, DJ Saul, RG Bell and DR Musgrave
Department of Biological Sciences, University of Waikato, Hamilton, New Zealand
A psychrotolerant Clostridium species was isolated from vacuum-packed,
...temperature-abused raw lamb. Colonies of this micro-organism on sheep-blood
agar were circular with an entire margin, grey-white, translucent and
beta-haemolytic. Cells were single, tapered, motile rods. Elliptical
subterminal spores were produced in the late stationary growth phase.
Spores did not cause swelling of the maternal cells. The micro-organism was
obligately anaerobic. In peptone yeast extract glucose starch (PYGS) broth
at pH 7.0, the micro-organism grew optimally between 25.5 and 30.0 degrees
C. The temperature range for growth was 2.5--32.2 degrees C. At 26 degrees
C, the micro-organism grew optimally at pH 6.8 to 7.0. The pH range for
anaerobic growth was 4.7--9.1. The micro-organism was saccharoclastic,
hydrolysed starch and degraded xylan. The fermentation products formed in
PYGS broth were acetate, formate, lactate, ethanol, butyrate, butanol,
hydrogen and carbon dioxide. The G+C content of the DNA was 38.4 mol%.
Phylogenetic analyses indicated that the strain belongs to cluster XIVa of
the genus Clostridium (sensu Collins et al. 1994). The new strain differed
from phylogenetically related clostridia in terms of cellular fatty acid
composition, soluble protein profiles and phenotypic properties. On the
basis of phenotypic and genotypic characterization data, the strain was
assigned to a new species, namely Clostridium algidixylanolyticum. The type
strain is strain SPL73(T) (=DSM 12273(T)).
Elderly women are at increased risk for bone loss and fractures. In previous cross-sectional and longitudinal studies of women residing in northern latitudes, bone loss was most pronounced during ...winter months and in those consuming less than 1 g calcium per day. In this study we sought to test the hypothesis that calcium supplementation by either calcium carbonate or dietary means would prevent seasonal bone loss and preserve bone mass. Sixty older postmenopausal women without osteoporosis were randomized to one of three treatment arms: Dietary milk supplementation (D-4 glasses of milk/day), Calcium carbonate (CaCO3-1000 mg/day in two divided doses), or placebo (P). After 2 yr, placebo-treated women consumed a mean of 683 mg/day of calcium and lost 3.0% of their greater trochanteric (GT) bone mineral density (BMD) (P < 0.03 vs. baseline); Dietary supplemented women averaged a calcium intake of 1028 mg/day and sustained minimal loss from the GT (-1.5%; P = 0.30), whereas CaCO3-treated women (total Ca intake, 1633 mg/day) suffered no bone loss from the GT and showed a significant increase in spinal and femoral neck BMD (P < 0.05). Femoral bone loss occurred exclusively during the two winters of the study (i.e. total loss, -3.2%; P < 0.02 in placebo-treated women) with virtually no change in GT BMD during summer. Serum 25-OH vitamin D declined by more than 20% (P < 0.001) in all groups during the winter months but returned to baseline in summer; PTH levels rose approximately 20% (P < 0.001) during winter but did not return to baseline during the summers. Urine N-telopeptide and osteocalcin levels increased significantly but only in the P-treated women and only during winter. Serum insulin growth factor binding protein 4, an inhibitory insulin growth factor binding protein, rose 15% (P < 0.03) from summer to winter, but this increase was significant only in those women consuming <1000 mg/day of calcium. By multivariate analysis, total calcium intake was the strongest predictor of bone loss from the hip. Urinary N-telopeptide also closely correlated with GT BMD but only during winter (P = 0.003). We conclude that calcium supplementation prevents bone loss in elderly women by suppressing bone turnover during the winter when serum 25-OH vitamin D declines and serum PTH increases. The precise amount of calcium necessary to preserve BMD in elderly women requires further studies, although in this study, at least 1000 mg/day of supplemental calcium was adequate prophylaxis against femoral bone loss.
A series of mono(cyclopentadienyl)titanium TEMPO (2,2,6,6-tetramethylpiperidine-N-oxyl) complexes were investigated by density functional theory (DFT) calculations to study the influence of the ...ligands on the Ti−O bond energies. Mono-Cp complexes with pendant amino groups were found to possess significantly weaker Ti−O bonds than those lacking pendant donor ligands. On the basis of DFT predictions, a novel mono-Cp pendant dimethylamino complex, CpNTiCl2(TEMPO) (12; CpN = C5H4CH2CH2N(CH3)2), was identified as a mono-Cp titanium TEMPO complex with a weak Ti−O bond (25 kcal/mol). The calculated bond energy of this complex is comparable to that of Cp2TiCl(TEMPO) (3; 17 kcal/mol). Thermolysis of 12 in the presence of CCl4 at 100 °C resulted in the formation of CpNTiCl3, consistent with the predicted low Ti−O bond energy.
A deep, nonlinear warm eddy advecting water that was also anomalously saltier, lower in oxygen, and higher in nutrients relative to surrounding waters was observed in moored current and temperature ...measurements and in hydrographic data obtained at a site ∼400 km off the coast of northern California. The eddy was reproduced using a nonlinear quasi‐geostrophic model, initialized by an iterative procedure using time series of 2‐day averaged moored current measurements. The procedure demonstrates how a data assimilative technique synthesizes and enhances the resolution of a relatively sparse data set by incorporating time‐dependence and model physics. The model forecast showed significant skill above persistence or climatology for 40 days. Our hypothesis, that the eddy was generated at the coast in winter and subsequently moved 400 km offshore by May, is consistent with the eddy movement diagnosed by the model and with the observations and coastal climatology. The model evolution significantly underpredicted the temperature anomaly in the eddy owing in part to unmodeled salinity compensation in trapped California Undercurrent water. Together, observations and model results show a stable nonlinear eddy in the California Current System that transported water and properties southwestward through the energetic eastern boundary region. Coherent features such as this one may be a mechanism for property transfer between the eddy‐rich coastal zone and the eddy desert of the eastern North Pacific Ocean.
The contribution of germline copy number variants (CNVs) to risk of developing cancer in individuals with pathogenic BRCA1 or BRCA2 variants remains relatively unknown. We conducted the largest ...genome-wide analysis of CNVs in 15,342 BRCA1 and 10,740 BRCA2 pathogenic variant carriers. We used these results to prioritise a candidate breast cancer risk-modifier gene for laboratory analysis and biological validation. Notably, the HR for deletions in BRCA1 suggested an elevated breast cancer risk estimate (hazard ratio (HR) = 1.21), 95% confidence interval (95% CI = 1.09-1.35) compared with non-CNV pathogenic variants. In contrast, deletions overlapping SULT1A1 suggested a decreased breast cancer risk (HR = 0.73, 95% CI 0.59-0.91) in BRCA1 pathogenic variant carriers. Functional analyses of SULT1A1 showed that reduced mRNA expression in pathogenic BRCA1 variant cells was associated with reduced cellular proliferation and reduced DNA damage after treatment with DNA damaging agents. These data provide evidence that deleterious variants in BRCA1 plus SULT1A1 deletions contribute to variable breast cancer risk in BRCA1 carriers.
Psychological morbidity after an acute myocardial infarction (AMI) is known to be common, but can be addressed by appropriate rehabilitation. The area in which this research was conducted experiences ...high rates of deprivation and of coronary heart disease and limited access to hospital-based rehabilitation. Responding to concern about psychological needs of AMI patients, a self-help package was introduced and evaluated alongside standard hospital-based cardiac rehabilitation.
To evaluate the impact of a home-based self-help package (the Heart Manual), alongside existing cardiac rehabilitation provision, on psychological morbidity and health status after AMI. A secondary aim was to assess the suitability of the Heart Manual for older patients aged over 80 years.
A controlled observational study, comparing two cohorts of patients discharged from hospital after AMI. The intervention group was given the self-help package in addition to standard care. The control group received standard care alone. Outcome measures used were the Hospital Anxiety and Depression Scale and the EuroQol.
The intervention group showed significant improvement in anxiety and depression scores after 3 months and nonsignificant improvement in general health status. Patients who attended hospital-based rehabilitation classes, and those aged over 80 years, also benefited from the intervention.
A home-based self-help rehabilitation package is an effective tool alongside hospital-based rehabilitation classes and can be given to all age groups.
The timing of flood basalt volcanism associated with formation of the Ontong Java Plateau (OJP) is estimated from paleomagnetic and paleontologic data. Much of OJP formed rapidly in less than 3 ...million years during the early Aptian, at the beginning of the Cretaceous Normal Polarity Superchron. Crustal emplacement rates are inferred to have been several times those of the Deccan Traps. These estimates are consistent with an origin of the OJP by impingement at the base of the oceanic lithosphere by the head of a large mantle plume. Formation of the OJP may have led to a rise in sea level that induced global oceanic anoxia. Carbon dioxide emissions likely contributed to the mid-Cretaceous greenhouse climate but did not provoke major biologic extinctions.
Sixty-four patients (66 elbows) treated for refractory cubital tunnel syndrome had minimal medial epicondylectomy and in situ decompression to minimize the potential disadvantages of classic medial ...epicondylectomy. After a mean followup of 27 months results were excellent in 27 patients (44%), good in 23 patients (35%), fair in 10 patients (15%), and poor in four patients (6%). No ulnar nerve palsy, ulnar nerve subluxation, or medial elbow instability were seen. The main complaint of patients regarding the procedure was tenderness at the osteotomy site. The results show that minimal medial epicondylectomy and in situ decompression of the ulnar nerve is a safe and effective method to treat patients with cubital tunnel syndrome. This procedure minimizes the disadvantage of medial instability and recurrent symptoms attributable to nerve trauma after a classic medial epicondylectomy.
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