Cold periods and coronary events: an analysis of populations worldwide

Study objective: To investigate the association between cold periods and coronary events, and the extent to which climate, sex, age, and previous cardiac history increase risk during cold weather. Design: A hierarchical analyses of populations from the World Health Organisation's MONICA project. Setting: Twenty four populations from the WHO's MONICA project, a 21 country register made between 1980 and 1995. Patients: People aged 35 - 64 years who had a coronary event. Main results: Daily rates of coronary events were correlated with the average temperature over the current and previous three days. In cold periods, coronary event rates increased more in populations living in warm climates than in populations living in cold climates, where the increases were slight. The increase was greater in women than in men, especially in warm climates. On average, the odds for women having an event in the cold periods were 1.07 higher than the odds for men (95% posterior interval: 1.03 to 1.11). The effects of cold periods were similar in those with and without a history of a previous myocardial infarction. Conclusions: Rates of coronary events increased during comparatively cold periods, especially in warm climates. The smaller increases in colder climates suggest that some events in warmer climates are preventable. It is suggested that people living in warm climates, particularly women, should keep warm on cold days.

High resolution provenancing of long travelled dust deposited on the Southern Alps, New Zealand

On 7 February 2000 an atypical orange discolouration of snowfields in the central Southern Alps, New Zealand occurred following the passage of a cold front. Analysis of snow samples identified fine orangey-brown dust mixed with much coarser grey dust. Air parcel forward trajectories from dust sources in southern and central Australia, where dust storms were reported on 4 February 2000, were computed to identify the deposits source. Geochemical analyses of the dust deposit using 26 trace elements, unaffected by regional air pollution and gravitational sorting, indicate that 20% of the dust was sourced from western New South Wales, with 45% from the eastern Eyre Peninsula of South Australia and the remaining 35% was local New Zealand dust. This provenancing approach provides a spatial resolution of long travelled dust sourcing not previously achieved. (c) 2005 Elsevier B.V. All rights reserved.

Minimising cold damage during reproductive development among temperate rice genotypes. I. Avoiding low temperature with the use of appropriate sowing time and photoperiod-sensitive varieties

Multiple-sown field trials in 4 consecutive years in the Riverina region of south-eastern Australia provided 24 different combinations of temperature and day length, which enabled the development of crop phenology models. A crop model was developed for 7 cultivars from diverse origins to identify if photoperiod sensitivity is involved in determining phenological development, and if that is advantageous in avoiding low-temperature damage. Cultivars that were mildly photoperiod-sensitive were identified from sowing to flowering and from panicle initiation to flowering. The crop models were run for 47 years of temperature data to quantify the risk of encountering low temperature during the critical young microspore stage for 5 different sowing dates. Cultivars that were mildly photoperiod-sensitive, such as Amaroo, had a reduced likelihood of encountering low temperature for a wider range of sowing dates compared with photoperiod-insensitive cultivars. The benefits of increased photoperiod sensitivity include greater sowing flexibility and reduced water use as growth duration is shortened when sowing is delayed. Determining the optimal sowing date also requires other considerations, e. g. the risk of cold damage at other sensitive stages such as flowering and the response of yield to a delay in flowering under non-limiting conditions. It was concluded that appropriate sowing time and the use of photoperiod-sensitive cultivars can be advantageous in the Riverina region in avoiding low temperature damage during reproductive development.

Bifurcations in the non-dissipative dynamics of ultra cold atoms

We present the first experimental observation of several bifurcations in a controllable non-linear Hamiltonian system. Dynamics of cold atoms are used to test predictions of non-linear, non-dissipative Hamiltonian dynamics.

A new equation for macroscopic description of capillary rise in porous media

Capillary rise in porous media is frequently modeled using the Washburn equation. Recent accurate measurements of advancing fronts clearly illustrate its failure to describe the phenomenon in the long term. The observed underprediction of the position of the front is due to the neglect of dynamic saturation gradients implicit in the formulation of the Washburn equation. We consider an approximate solution of the governing macroscopic equation, which retains these gradients, and derive new analytical formulae for the position of the advancing front, its speed of propagation, and the cumulative uptake. The new solution properly describes the capillary rise in the long term, while the Washburn equation may be recovered as a special case. (C) 2004 Elsevier Inc. All rights reserved.

Optimization of pipeline transport for CO2 sequestration

Coal fired power generation will continue to provide energy to the world for the foreseeable future. However, this energy use is a significant contributor to increased atmospheric CO2 concentration and, hence, global warming. Capture and disposal Of CO2 has received increased R&D attention in the last decade as the technology promises to be the most cost effective for large scale reductions in CO2 emissions. This paper addresses CO2 transport via pipeline from capture site to disposal site, in terms of system optimization, energy efficiency and overall economics. Technically, CO2 can be transported through pipelines in the form of a gas, a supercritical. fluid or in the subcooled liquid state. Operationally, most CO2 pipelines used for enhanced oil recovery transport CO2 as a supercritical fluid. In this paper, supercritical fluid and subcooled liquid transport are examined and compared, including their impacts on energy efficiency and cost. Using a commercially available process simulator, ASPEN PLUS 10.1, the results show that subcooled liquid transport maximizes the energy efficiency and minimizes the Cost Of CO2 transport over long distances under both isothermal and adiabatic conditions. Pipeline transport of subcooled liquid CO2 can be ideally used in areas of cold climate or by burying and insulating the pipeline. In very warm climates, periodic refrigeration to cool the CO2 below its critical point of 31.1 degrees C, may prove economical. Simulations have been used to determine the maximum safe pipeline distances to subsequent booster stations as a function of inlet pressure, environmental temperature and ground level heat flux conditions. (c) 2005 Published by Elsevier Ltd.

Genotypic variation for cold tolerance during reproductive development in rice: Screening with cold air and cold water

Rice (Oryza sativa L.) plants are susceptible to low temperature during the young microspore stage, which occurs 10-12 days before heading. Low temperature at this time increases spikelet sterility which can cause massive yield loss. Increasing the cold tolerance of cultivars can reduce yield variability in temperate rice-growing environments. Two experiments were conducted in cold air screenings and two were conducted in cold water screenings to examine genotypic variation for cold tolerance, explore flowering traits related to spikelet sterility, and investigate whether the results reflect the level of cold tolerance determined previously in the field. Cold air screenings imposed day/night temperatures of 27 degrees C/13 degrees C, 25 degrees C/15 degrees C and 32 degrees C/25 degrees C following particle initiation until 50% heading, while cold water screenings maintained a relatively constant 19 degrees C. The variation in the commencement of low air temperature treatment did not have an effect on the level of spikelet sterility, indicating that exposure to low temperature during the young microspore stage was more important than the duration of exposure. Spikelet sterility of common cultivars showed a significant correlation between cold air and cold water screenings (r(2) = 0.63, p < 0.01), cold air and field screenings (r(2) = 0.52, p < 0.01) and cold water and field screenings (r(2) = 0.53, p < 0.01), indicating that cold air and cold water can be used for screening genotypes for low temperature tolerance. HSC55, M 103 and Jyoudeki were identified as cold tolerant and Doongara, Sasanishiki and Nipponbare as susceptible cultivars. There was a significant negative relationship between spikelet sterility and both the number of engorged pollen grains per anther and anther area only after imposing cold air and cold water treatment hence, it was concluded that these flowering traits were facultative in nature. In addition, cultivars originating from Australia and California were inefficient at producing filled grain with similar sized anthers containing a similar number of engorged pollen grains as cultivars from other origins. One suggested reason for this poor conversion to filled grain of cultivars from Australia and California may be associated with their small stigma area, particularly when exposed to low temperature conditions. (c) 2006 Elsevier B.V. All rights reserved.

Fighting fit: thermal plasticity of metabolic function and fighting success in the crayfish Cherax destructor

1. We examined the effect of thermal acclimation on fighting success and underlying performance traits in the crayfish Cherax destructor. We tested the hypothesis that animals will be more successful when fighting at their acclimation temperature than at a colder or warmer temperature, and that changes in metabolic capacity underlie differences in behavioural performance. 2. Thermal acclimation (to 20 degrees C and to 30 degrees C) had a significant effect on behavioural contests, and the likelihood of winning was significantly greater when individuals fought at their acclimation temperature against an individual from an alternate acclimation temperature. 3. The ratio of ADP stimulated respiration to proton leak (respiratory control ratio) of isolated mitochondria increased significantly in chelae muscle of the cold-acclimated group, and differences in respiratory control ratio between winners and losers were significantly correlated with the outcome of agonistic encounters. However, acclimation did not affect tall muscle mitochondria or the activity of pyruvate kinase in either chelae or tail muscle. 4. The force produced by closing chelae was thermally insensitive within acclimation groups, and there were no significant differences between acclimation treatments. None the less, differences in chelae width between contestants were significantly correlated with the outcome of agonistic encounters, but this perceived resource holding power did not reflect the actual power of force production. 5. Thermal acclimation in C destructor has beneficial consequences for dominance and competitive ability, and the success of cold acclimated animals at the cold temperatures can be at least partly explained by concomitant up-regulation of oxidative ATP production capacity.

40Ar/39Ar geochronological constraints on the evolution of lateritic iron deposits in the Quadrilatero Ferrifero, Minas Gerais, Brazil

Weathering profiles overlying the Sapecado, Pico and Andaime iron ore deposits, Quadrilátero Ferrífero (QF), Minas Gerais, Brazil, reach depths of 150–400 m and host world-class supergene iron orebodies. In addition to hosting supergene ore bodies of global economic significance, weathered banded iron-formations at the Quadrilátero Ferrífero and elsewhere (e.g., Carajás, Hamersley) are postulated to underlie some of the most ancient continuously exposed weathering profiles on earth. Laser incremental-heating 40Ar/39Ar results for 69 grains of hollandite-group manganese oxides extracted from 23 samples collected at depths ranging from 5 to 150 m at the Sapecado, Pico and Andaime deposits reveal ages ranging from ca. 62 to 14 Ma. Older Mn-oxides occur near the surface, while younger Mn-oxides occur at depth. However, many samples collected at the weathering–bedrock interface yield ages in the 51–41 Ma range, suggesting that the weathering profiles in the Quadrilátero Ferrífero had already reached their present depth in the Paleogene. The antiquity of the weathering profiles in the Quadrilátero Ferrífero is comparable to the antiquity of dated weathering profiles on banded iron-formations in the Carajás Region (Brazil) and the Hamersley Province, Western Australia. The age versus depth distributions obtained in this study, but not available for other regions containing similar supergene iron deposits, suggest that little further advance of the weathering front has occurred in the Quadrilátero Ferrífero lateritic profiles during the Neogene. The results suggest that weathering in some of these ancient landscapes is not controlled by the steady-state advance of weathering fronts through time, but may reflect climatic and geomorphological conditions prevailing in a remote past. The geochronological results also confirm that the ancient landsurfaces in the Quadrilátero Ferrífero probably remained immune to erosion for tens of millions of years. Deep weathering, mostly in the Paleogene, combined with low erosion rates, account for the abundance and widespread distribution of supergene iron, manganese, and aluminum orebodies in this region.