Changes In Physical Conditions Research Articles

Risk Indexing Tool to Assist in Prioritizing Improvements to Embankment Dam Inventories

A risk indexing tool is proposed to assist in the prioritization of maintenance, repair, and evaluation tasks on embankment dams that are generally less than 33 m (100 ft) high and for which there is little or no instrumentation, limited or no information concerning as-built conditions, and little or no information on the performance history. Under such circumstances, there may not be enough information available to perform anything other than an ''indexing'' type of analysis to assist in prioritization. The risk indexing tool is based upon identifying potential deficiencies in the physical condition of the dam and rating the overall importance of these deficiencies to the safety of the structure. It is meant as an index of risk (indication) and not as a direct measure of risk. Checklists are presented for onsite inspections to determine current physical condition. Condition is defined in terms of a condition function that is based upon a condition indexing scale. Four potential failure modes are considered: (1) overtopping; (2) external erosion; (3) piping; and (4) mass movement (slope insta- bility). Absolute probabilities are specifically not factored into the analysis. Conditional probabilities are esti- mated for each failure mode using a Bayesian updating procedure based on dam attributes. A simple failure criticality analysis is performed wherein specific changes in physical condition of the dam are considered to contribute to the probability of failure for each mode. From this failure criticality analysis and the conditional probabilities of failure, the relative importance of the various changes in physical condition is determined. The physical condition and the relative importance are then combined for each observable deficiency to form a risk index. These risk indices are used to prioritize expenditures for improvements on the premise that actions to address the most significant physical deficiencies are preferred.

Embodiment-Based Object Recognition for Vision-Based Mobile Agents

In this paper, we propose a new architecture for object recognition based on the concept of ""embodiment"" as a primitive function for a cognitive robot. We define the term ""embodiment"" as the extent of the agent itself, locomotive ability, and its sensor. Based on this concept, an object is represented by reaching action paths, which correspond to a set of sequences of movement by the agent for reaching the object. Such behavior is acquired by trial-and-error based on visual and tactile information. Visual information is used to obtain sensorimotor mapping, which represents the relationship between the change of an object's appearance and the movement of the agent. Tactile information is used to evaluate the change of physical condition of the object caused by such movement. By such means, the agent can recognize an object regardless of its position and orientation in the environment. To demonstrate the feasibility of our method, we detail experimental results of computer simulation.

Burrowing activity in the sand‐bubbler crab, Dotilla fenestrata (Crustacea, Ocypodidae), inhabiting a mangrove swamp in Kenya

AbstractSeveral species of crabs belonging to the family Ocypodidae are burrowers; they inhabit tropical sandy and muddy shores, including mangrove swamps, exposed to extreme conditions of intertidal areas. Dotilla fenestrata, the only East African representative of the subfamily Scopimerinae, exhibits high flexibility in its burrowing activity. Only part of the population has an exclusively burrow‐orientated activity, whereas most individuals form dense aggregations or droves, that during the phase of diurnal low water move away from the normal distribution zone. Burrows are built according to two different architectural designs, the feeding‐trench burrow and the igloo, which then constitute their territory. A resident will lose a contest for the burrow when the attacker is larger. When the ground is uncovered at low tide, emergence can be delayed or even fail to occur, and some crabs remain buried during the entire low water period. Only 50+ of crabs remain faithful to the original burrow, while the others either leave it to occupy an empty one or dig a new burrow, or join the wandering drove. The spatial distribution of burrows from the high water neap level (our reference point) to the sea, differs during both spring and neap tides, and both diurnal and nocturnal tides. The differences may be due partly to the change of physical conditions, such as drainage and substrate grade (although within a mangrove swamp these do not follow a consistent gradient), but mostly may be related to the trade‐off between the benefits and costs of living at different intertidal levels. With its burrowing and feeding activity leading to the re‐deposition of excavated and pseudofaecal pellets, Dotilla plays a role as a sediment mover in this very specialized habitat. The results obtained from this study are compared with those reported in other ocypodids.

電話による退院患者のフォローアップ

Follow-up case by telephone was conducted for the discharged patients, who had received the medication consulting services from clinical pharmacists of Kobe university hospital. In this trial, we focused on the patients in the Department of Circulation and Respiratory Diseases. The follow-up case by telephone was carried out from the time of discharge until the next visit (almost 2 weeks after discharge). The patients consisted of 30 men and 17 women (average age was 66.9 years old). By telephone, the following issues were questioned; 1 : medication compliance, 2 : side effects and/or the changes of physical condition, 3 : other issues (such a when an inappropriate use of medicine had been suspected during hospitalization). When the patients so desire they could come in for a check-up anytime. More than about 90% of patients reported to keep good medication compliance and to have no significant side effects. However, 34% of patients claimed a slight of change in their physical condition including dropsical swelling, boiling and gasping. The claims were found more frequency in patients who had been suspected of inappropriately taking their medication. Follow-up care by telephone was found to be an effective way to avoid any kind of risks including the discontinuation of medicine. As a result, although further examinations should be addressed, follow-up care by telephone appears to be a good way to ensure the appropriate use of medicine.

LONG-TOED SALAMANDERS IN HARVESTED AND INTACT DOUGLAS-FIR FORESTS OF WESTERN MONTANA

There is little known about how timber harvest practices have affected ter- restrial amphibians in the northern Rocky Mountains. Especially lacking is information on the effects of revised harvest methods that fall within the framework of environmental or New Forestry. We estimated the relative abundance of a common forest amphibian, the long-toed salamander (Ambystoma macrodactylum) captured in pitfall arrays on intact, environmentally harvested, and overstory-removal harvested sites in mixed-conifer forests of western Montana. Pitfall data from 1994 through 1996 showed that previously logged sites contained significantly fewer long-toed salamanders regardless of harvest method used. The number of salamanders captured on intact sites (3.1 salamanders.(array)-1.(100 d)-') was nearly three times the number captured on logged sites (1.2 salamanders4(array)-14(100 d)-1). Habitat conditions measured in conjunction with trapping efforts indicated that lower amphibian abundance was associated with decreased numbers of large live trees. Declines in amphibian abundance occurred in the absence of changes in understory vegetation that typically occur when forest canopy is reduced. Our findings suggest that long-toed sala- manders responded to changes in the physical environment, probably increased temperatures and decreased moisture. That salamanders should respond so dramatically indicates that immediate changes in physical conditions may profoundly alter habitat quality even when other components of the habitat are unaffected.

Jornada Experimental Range: A Unique Arid Land Location for Experiments to Validate Satellite Systems

The Jornada Experimental Range (Jornada) in southern New Mexico provides a unique opportunity to use remote sensing techniques to study arid rangeland and the responses of vegetation to changing hydrologic fluxes and atmospheric driving forces. Research by the United States Department of Agriculture Forest Service and Agricultural Research Service at Jornada has been continuous since 1912. The Jornada has been a National Science Foundation Long-Term Ecological Research site since 1981. These long-term investigations have provided ground data on vegetation characteristics, ecosystem dynamics, and vegetation response to changing physical and biological conditions. To complement the programs of ground measurements, a campaign called JORNEX (JORNada EXperiment) began in 1995 to collect remotely sensed data from aircraft and satellite platforms to provide spatial and temporal data on physical and biological states of the Jornada rangeland. A wide range of ground, aircraft, and satellite data have been collected on the physical, vegetative, thermal, and radiometric properties of three ecosystems (grass, grass/shrub transition, and shrub) typical of the Jornada rangeland and of southwestern U.S. deserts. Spatial surface energy balance estimates were made from a combination of parameters and state variables estimated from aircraft and ground data. Landscape surface roughness was evaluated with the laser altimetry data and used to estimate aerodynamic roughness. Data from different platforms allowed the evaluation of the landscape at different scales. These measurements are being used to quantify hydrologic budgets and plant responses to change in components in the water and energy balance at the Jornada.

Use of ‘functional habitats’ to link ecology with morphology and hydrology in river rehabilitation

1. This paper examines the influence of channel morphology and hydraulics on the occurrence and diversity of ‘functional habitats’ (also called ‘meso-habitats’) in semi-natural and physically degraded rivers. 2. The depths and velocities at which each functional habitat is most likely to be found are described using ‘occurrence matrices’. In most cases, each habitat was associated with distinct depth-velocity conditions. 3. The relationship between habitat occurrence, diversity and river degradation was examined. The deviation of a site from its predicted natural summer wetted width was used as an index of physical degradation. Habitat diversity (measured as the Shannon index) was low for sites that were wider than expected for natural conditions. This was independent of the type of physical perturbation causing the width deviation. 4. Two main types of physical perturbation were identified in the degraded river: over-widening and ponding. Over-widened sites were shallow, slow and dominated by silt and emergent macrophyte habitats. Ponded sites were deep, slow and dominated by floating-leaved macrophyte and macroalgal habitats. 5. River reaches of uniform depth had low habitat diversity compared with reaches containing both shallow and deep areas. 6. It is recommended that objective assessment of the type and extent of physical degradation, prior to restoration, should be made by measurement of depth, velocity, width and functional habitat distribution. Changes in channel morphology should then be designed to create the necessary range of depths and widths, and therefore velocities and habitat types, deemed desirable for that river site. Habitats that are over-dominant or rare can be identified and the ‘occurrence matrices’ used to inform decisions about the change in physical conditions needed to enhance or suppress that habitat. 7. The approach is a cost-effective way to link ecology with morphology and hydrology in river channel rehabilitation. Copyright © 1999 John Wiley & Sons, Ltd.

Testing Dutch and French Translations of the SF-36 Health Survey among Belgian Angina Patients

The psychometric properties of the Belgian Dutch and French translations of the SF-36 Health Survey were evaluated in a sample of 4448 Belgian patients with angina enrolled in a 6-month treatment study. Missing data were rare (<2%), and tests of both item internal consistency and item discriminant validity were satisfactory in both languages. Cronbach’s alpha coefficient ranged from 0.81 to 0.91 (Dutch) and 0.82 to 0.92 (French). SF-36 scales discriminated between groups of patients differing in age and in the number of weekly angina attacks. change over 6 months in the number of weekly angina attacks and physician assessment of change in physical condition both were significantly related to changes in SF-36 scale scores. On average, scale scores for French-speaking patients were lower than for Dutch-speaking patients, most notably for Vitality and Mental Health. The average change in SF-36 scale scores over 6 months, in relation to change in clinical criteria, was similar in both language groups. The psychometric properties of the Belgian Dutch and French translations should be tested further in Belgium to determine whether the generally favorable results reported here can be replicated in other samples.

Plant uncertainty analysis in a duct active noise control problem by using the H∞ theory

Plant uncertainty is one of the major contributing factors that could affect the performance as well as stability of active noise control (ANC) systems. Plant uncertainty may be caused by either the errors in modeling, computation, and measurement, or the perturbations in physical conditions. These factors lead to deviations of the plant from the nominal model, which will in turn affect the robustness of the control system. In this paper, the effects due to changes in physical conditions on the ANC system are investigated. The analysis is carried out in terms of performance and robustness by using a general framework of the H∞ robust control theory. The size of plant uncertainty is estimated according to the infinity norm of the perturbations to physical conditions, which provides useful information for subsequent controller design that accommodates both performance and stability in an optimal and robust manner. The guidelines for designing the ANC systems with reference to plant uncertainties are also addressed.

Metabolic Rate, Temperature Regulation, and the Energetic Implications of Roost Nests in the Bananaquit (Coereba flaveola)

identification guide to the ducks, geese and swans of the world. Houghton Mifflin, Boston. MAINGUY, S. K., AND V. G. THOMAS. 1985. Comparisons of body reserve buildup and use in several groups of Canada Geese. Canadian Journal of Zoology 63:1765-1772. MILLER, M. R. 1986. Molt chronology of Northern Pintails in California. Journal of Wildlife Management 50:57-64. OWENS, N. W. 1977. Responses of wintering Brent Geese to human disturbance. Wildfowl 28:5-14. PAYNE, R. B. 1972. Mechanisms and control of molt. Pages 104-157 in Avian biology, vol. 2 (D. S. Farner and J. R. King, Eds.). Academic Press, New York. PETRIE, S. A. 1996. Red-billed Teal foods in semiarid South Africa: A north-temperate contrast. Journal of Wildlife Management 60:874-881. PETRIE, S. A. 1998. Nutrient reserve dynamics, foraging strategies, molt patterns and movements of White-faced Whistling Ducks in South Africa. Ph.D. dissertation, University of the Witwatersrand, Johannesburg, South Africa. PETRIE, S. A., AND V. PETRIE. 1998. Activity budget of White-faced Whistling Ducks during winter and spring in northern KwaZulu-Natal, South Africa. Journal of Wildlife Management 62:11191126. PETRIE, S. A., AND K. H. ROGERS. 1996. Foods consumed by breeding White-faced Whistling Ducks on the Nyl River floodplain, South Africa. Proceedings of the Anatidae 2000 Conference, Strasbourg, France, 5-9 December 1994 (M. Birkan, J. van Vessem, P. Havet, J. Madsen, B. Trolliet, and M. Moser, Eds.). Gibier Faune Sauvage 13:755-771. RAVELING, D. G. 1979. The annual cycle of body composition of Canada Geese with special reference to control of reproduction. Auk 96:234-252. SIEGFRIED, W. R. 1970. Wildfowl distribution, conservation and research in southern Africa. Wildfowl 21:89-98. SIEGFRIED, W. R. 1974. Brood care, pair bonds and plumage in southern African Anatini. Wildfowl 25:33-40. SMITH, L. M., AND D. G. SHEELEY. 1993. Molt patterns of wintering Northern Pintails in the Southern High Plains. Journal of Wildlife Management 57: 229-238. WATKEYS, M. K., T. R. MASON, AND P. S. GOODMAN. 1993. The role of geology in the development of Maputuland, South Africa. Journal of African Earth Sciences 16:205-221. WISHART, R. A. 1985. Moult chronology of American Wigeon, Anas americana, in relation to reproduction. Canadian Field-Naturalist 99:172-178. YOUNG, D. A., AND D. A. BOAG. 1982. Changes in physical condition of male Mallards (Anas platyrhynchos) during moult. Canadian Journal of Zoology 60:3220-3226.

On the origin of medium-period ionospheric waves and their possible modelling: a short review

This article introduces the concept of ionospheric waves with periods from about 15 min to about 4 h as one of the acoustic-gravity wave-induced phenomena. The existence of these medium-period ionospheric waves in the various ionospheric layers is supported by the results of a data analysis which has shown remarkable characteristics in occurrence and direction of the waves with a period not longer than about 2 h. The explanation offered is based on the assumption that a unique phenomenon capable to launch acoustic-gravity waves related to such ionospheric waves is the sudden change in physical conditions of the atmosphere due to the passage of the solar terminator.

Calibration of [formula omitted] fractionation during subcritical phase separation of seawater: Possible halite at 9 to 10°N East Pacific Rise

Experiments were conducted to assess Br Cl fractionatiodn during phase separation of seawater at 400°C and 250 to 275 bars. These conditions are applicable to the 9–10°N EPR system where low Cl concentrations and low Br Cl rations in vent fluids have been attributed to phase separation of seawater at conditions below the critical point of seawater (408°C, 300 bars). The level of Br Cl fractionation observed in experiments is well below that needed to account for Br Cl systematics at EPR 9–10°N. Based on our experimental results, we propose an alternative model involving dissolution and precipitation of halite to account for the anomalous Br Cl data at 9–10°N. Halite can be predicted to form at pressure and temperature conditions prevailing during eruption of magma at mid-ocean ridges. Subsequent changes in physical conditions, however, would induce halite to dissolve, and thus, decrease Br Cl ratios of vent fluids.

The Density and Temperature of Molecular Clouds in M33

We have observed the 12CO J = 2-1,13CO J = 2-1, and 12CO J = 3-2 lines in a sample of seven giant molecular clouds in the Local Group spiral galaxy M33 using the James Clerk Maxwell Telescope. The 12CO/13CO J = 2-1 line ratio is constant across the entire sample, while the observed 12CO J = 3-2/J = 2-1 line ratio has a weak dependence on the star formation environment of the cloud, with large changes in the line ratio seen only for clouds in the immediate vicinity of an extremely luminous H II region. A large velocity gradient analysis indicates that clouds without H II regions have temperatures of 10-20 K, clouds with H II regions have temperatures of 15-100 K, and the cloud in the giant H II region has a temperature of at least 100 K. Interestingly, the giant H II region appears capable of raising the kinetic temperature of the molecular gas only for clouds that are quite nearby (<100 pc). The continuous change of physical conditions across the observed range of star formation environments suggests that the unusual physical conditions in the cloud in the giant H II region are due to post-star formation changes in the molecular gas, rather than intrinsic properties of the gas related to the formation of the giant H II region. The results from this study of M33 suggest that similar observations of ensembles of giant molecular clouds in more distant normal spiral galaxies are likely to give meaningful measurements of the average physical conditions inside the molecular clouds. These results also imply that clouds with a factor of 3 difference in metallicity have similar density and temperature, which in turn implies that the differences in the CO-to-H2 conversion factor seen in these clouds can be attributed to metallicity effects entirely.

Zooplankton community response to reservoir aging

Changes in zooplankton diversity and density in response to reservoir aging in Pawnee Reservoir were investigated. Zooplankton samples collected from April 1992 through April 1993, were compared to a similar study conducted after initial impoundment by Helzer (1971), in 1968–1970. Since this initial study, increases in turbidity and resulting changes in biotic interactions significantly altered the zooplankton community. A significant increase in total zooplankton density and a decrease in species richness were observed between study periods. Density increased from 24.6 to 95.4 individuals L−1, while the number of taxa declined from fourteen to ten. During this time period, Cyclops vernalis became the dominant zooplankter in the reservoir. The density of this predatory copepod increased significantly, from ≤ 0.1 l−1 in 1968–1970, to 44.3 l−1 in 1992–1993, which accounted for most of the increase in total zooplankton density. Though a greater spring maximum of another dominant, Bosmina spp. was found during the 1992–1993 study period, the annual density of this cladoceran was not significantly different between study periods. Similar trends for Daphnia ambigua and D. parvula were also observed, as greater spring maxima levels were attained, however overall annual densities were not significantly different. The dominance of C. vernalis (46% of annual density) and Bosmina spp. (33%), indicate that these two zooplankters were tolerant of changes in physical conditions resulting from reservoir aging and biotic interactions that followed in the reservoir during the 22 years between study periods.

Seismic anisotropy near source region in subduction zones around Japan

Broad-band seismographs have been distributed widely over the Japanese islands and have provided us with high-quality digital waveform data in recent years. We have investigated splitting of ScS waves from deep earthquakes in the Kuril and Izu-Bonin subduction zones recorded on the STS seismograms. We used ScS waves from 13 events observed in Japan and recognized shear-wave splitting which is mainly caused by anisotropy in the lithospheric slab. The anisotropy was confirmed around the source region by comparing ScS-wave splitting from deep earthquakes in different regions and at different depths with S-wave splitting from deep events just beneath central Japan. We have found that the anisotropic regions exist within the subducting slab, although they are distributed locally in and around the source, possibly as patches with a diameter of 100 km or less. Discrepancy in the direction of the fast polarized shear waves between two nearby events is observed in the Izu-Bonin subduction zone: the splitting of the shallower event (289 km) shows its fast polarization direction to be parallel to the fossil motion of the Pacific plate, but that of the deeper event (361 km) immediately beneath is parallel to the current motion. These observations suggest that the change in shear-wave splitting with depth comes from the modification of preferred orientation of minerals depending on depth. We propose in this study that the reorientation of minerals (olivine) occurs owing to the change in physical conditions associated with the phase transformation of olivine (α phase) to modified spinel (β phase).

Stream Channelization and Changing Vegetation Patterns in the U. S. Coastal Plain

The southeastern U.S. Coastal Plain contains high-density stream networks and the largest area of alluvial wetlands in North America. Among the most common flood-control methods in this region is stream channelization. Its purpose is to increase channel capacity and flow velocity so that water moves more efficiently downstream and thereby reduces flooding. Channelization typically includes deepening and widening the stream channel and shortening it by cutting off meanders. Landowners and those who cultivate in the adjacent floodplains are the primary beneficiaries. In addition to closely involved government agencies, such as the U.S. Army Corps of Engineers and the U.S. Soil Conservation Service, local landowners have been the strongest advocates for channelization. Awareness of the physical and biological problems caused by channelization is growing. Environmental degradation of alluvial habitats has been given serious attention in channelization project planning in recent years. Less destructive channel modifications have been implemented, and some attempts have been made to restore riparian habitats affected by channelization. For example, the Kissimmee River in south Florida, which was channelized in the 1960s, is being restored by reintroducing river flow into remnant channels (Loftin, Toth, and Obeysekera 1990; Shen, Tabios, and Harder 1994). The primary justification is the reestablishment of natural hydrologic conditions and the consequent enhancement of the river's biological resources. A similar restoration project is in the early planning stages for the Obion-Forked Deer River system in western Tennessee, also channelized in the 1960s. The destructive effects of channelization on water quality and aquatic ecosystems are well documented in Brookes's review of 1988. But until recently, little attention has been paid to the effects of channelization on bottomland terrestrial ecosystems. Flood frequency and related physical conditions (including the depth of surface water and the water table, as well as the accumulation of sediment and organic matter) are among the most important factors controlling the presence and distribution of bottomland terrestrial species and are the basis for most classifications of floodplain plant communities (Penfound 1952; Huffman and Forsythe 1981; Wharton and others 1982). Stream channelization significantly alters these conditions in the adjacent bottomlands. But few attempts have been made to link changes in floodplain hydrogeomorphic conditions following stream channelization directly to plant-community composition. Western Tennessee and northwestern Mississippi is an area of the Gulf Coastal Plain in which almost all of the major streams and many of their large and small tributaries have been channelized [ILLUSTRATION FOR FIGURE 1 OMITTED]. These river systems have been studied extensively, and much is known about channel behavior, floodplain hydrology, and bottomland vegetation (Schumm, Harvey, and Watson 1984; Hupp 1987; Simon and Hupp 1987; Simon 1989, 1994; Shankman and Drake 1990; Shankman and Pugh 1992). But the response of forest communities to changing physical conditions is by no means clear. Most floodplain tree species in this region live for decades or centuries, which greatly exceeds the amount of time that has elapsed since extensive channelization began. As a result, short-term observations of bottomland forest are, in all but a few cases, unlikely to reveal forthcoming changes. In this article I examine the potential effects of channelization on bottomland terrestrial habitats in the southeastern United States. Probable changes induced by channelization in forest communities are assessed based on geomorphic processes and life-history characteristics of common bottomland species. In addition, changes in flooding, sedimentation, and restricted-channel migration that follow channelization are evaluated. Changes in natural hydrogeomorphic conditions are directly linked to floodplain habitats and to regeneration of bottomland species. …

Gas geochemical changes at mineral springs associated with the 1995 southern Hyogo earthquake (M = 7.2), Japan

Gas concentrations monitored at a mineral spring in central Japan over the past 15 years showed similar changes before and after two large earthquakes (September 1984, M = 6.9, 50 km distant: and January 1995, M = 7.2, 220 km distant); namely, a concurrent and abrupt drop in all three gas ratios, HeAr, N2Ar, and CH4Ar, several months before the events. Improved measurements of gas compositions since 1991 and the addition of gas discharge rate monitoring since 1993 disclosed the following features for anomalies in response to small earthquakes as well as the large 1995 event: (1) the gas ratios increased for both large and small earthquakes, but they did not return to the preseismic values for the large event, as they did within a few hours for the small events; (2) at the 1995 event, the gas discharge rate decreased remarkably 3 h before the event and then increased to higher than preseismic level for several months. In contrast, coseismic rates at small events generally increased for less than 15 min; (3) during a seismically quiet period, from January 1993 to December 1994, the variation in the HeAr ratio was well correlated with that of gas discharge rate. Such correlation disappeared in August and September, 1994, when the three gas ratios dropped before the large event; (4) gas compositions at an auxiliary monitoring site revealed a coseismic change similar to that described above for the 1995 event. These lines of evidence show that subsurface fluids may habitually respond to changes in physical conditions relating to earthquake occurrences, and thus suggest the usefulness of monitoring subsurface fluids for earthquake prediction.

Spectroscopic measurements of element abundances in the solar corona: Variations on the FIP theme

Solar wind and solar energetic particle (SEP) data yield systematic differences between elemental abundances in the corona and in the photosphere related to the first ionization potential (FIP) of the elements: low-FIP elements are preferentially enhanced relative to high-FIP elements by about a factor of four. Spectroscopic studies of the inner corona show that such a pattern may apply on average but not in detail for coronal loops: substantial abundance differences occur between different types of coronal structures, and variations have been found from flare to flare, from one active region to another, and over time in the same region; further, in some flares, anomalies such as enhanced Ne:O ratios, distinctly at odds with the FIP pattern, show that a competing element selection mechanism sometimes operates. Details of the observed abundance variability — such as the magnitude of the variations, the relevant temporal and spatial scales, and correlations with other properties of the given coronal structure — may give important clues to the processes which supply and heat the corona, or they may reflect the changing physical conditions or locations where those processes take place. However, many such details remain to be established definitively. At present, abundance variability is primarily a major complication to data analysis and interpretation. However, once it is better understood, it may provide a new diagnostic tool for probing the lower layers of the solar atmosphere.

Problems of cardiac patients in early recovery

Most studies of the problems and information needs of patients describe these only for the period of hospitalization. In this study, however, the authors focused on the first 6 months after discharge. Eighty-two cardiac patients, admitted to a university hospital with a myocardial infarction (MI) or for coronary artery bypass surgery (CABS), were interviewed 6 months after discharge. Questions required them to describe problems they experienced in early recovery and what information they needed. All but one of the 82 patients stated they had experienced problems during the first 6 months after discharge. Most problems described concerned: emotional reactions (59%), their change in physical condition (59%), deleterious effects of treatment (56%) and convalescence (54%). Topics on which most patients needed additional or different information were: deleterious effects of the treatment (26%), physical condition (24%), risk factors (24%), convalescence (24%) and knowledge of the disease (24%).

Fluctuation in porosity and fluid pressure during hydrothermal events: textural evidence in the Emuford District, Australia

The Upper Paleozoic granites of the Emu Suite, north Queensland, show varying degrees of alteration. The petrographic and microstructural survey of albite-rich zones reveals the spatial overprint of hydrothermal events which are more correlated with changes in physical conditions (permeability, fluid pressure and flow regime) rather than with chemical variations of the percolating fluids. The sequence of alteration events chronologically comprises: (1) in situ substitution of primary microline to chessboard albite; (2) dissolution of magmatic quartz resulting in the formation of interconnected vugs; (3) formation of concentric cracks around some vugs; (4) infilling of vugs; and (5) development of a dense system of closely spaced, sheeted veinlets by a crack-seal process. The first two stages indicate an increase of the global permeability of the albite zones (chemically induced porosity), whereas the vug- and vein-filling stages indicate the reverse, resulting in an increase of fluid pressure from nearly hydrostatic to nearly lithostatic values (mechanically induced porosity). This contrast is discussed from micro- and mesostructural arguments and from results of a fluid inclusion investigation; it is explained by the progressive focusing of the circulating fluids via grain boundaries, then vugs, and through tapping by late-stage microfracturing.