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1.
PeerJ ; 11: e15962, 2023.
Article in English | MEDLINE | ID: mdl-37790628

ABSTRACT

Declines and extirpations of American pika (Ochotona princeps) populations at historically occupied sites started being documented in the literature during the early 2000s. Commensurate with global climate change, many of these losses at peripheral and lower elevation sites have been associated with changes in ambient air temperature and precipitation regimes. Here, we report on a decline in available genetic resources for an iconic American pika metapopulation, located at the southwestern edge of the species distribution in the Bodie Hills of eastern California, USA. Composed of highly fragmented habitat created by hard rock mining, the ore dumps at this site were likely colonized by pikas around the end of the 19th century from nearby natural talus outcrops. Genetic data extracted from both contemporary samples and archived natural history collections allowed us to track population and patch-level genetic diversity for Bodie pikas across three distinct sampling points during the last half- century (1948-1949, 1988-1991, 2013-2015). Reductions in within-population allelic diversity and expected heterozygosity were observed across the full time period. More extensive sampling of extant patches during the 1988-1991 and 2013-2015 periods revealed an increase in population structure and a reduction in effective population size. Furthermore, census records from the last 51 years as well as archived museum samples collected in 1947 from a nearby pika population in the Wassuk range (Nevada, USA) provide further support of the increasing isolation and genetic coalescence occurring in this region. This study highlights the importance of museum samples and long-term monitoring in contextualizing our understanding of population viability.


Subject(s)
Lagomorpha , Animals , Nevada , Lagomorpha/genetics , Censuses , Ecosystem , Climate Change
2.
Ecol Appl ; 33(5): e2888, 2023 07.
Article in English | MEDLINE | ID: mdl-37212209

ABSTRACT

Wildfires may facilitate climate tracking of forest species moving upslope or north in latitude. For subalpine tree species, for which higher elevation habitat is limited, accelerated replacement by lower elevation montane tree species following fire may hasten extinction risk. We used a dataset of postfire tree regeneration spanning a broad geographic range to ask whether the fire facilitated upslope movement of montane tree species at the montane-to-subalpine ecotone. We sampled tree seedling occurrence in 248 plots across a fire severity gradient (unburned to >90% basal area mortality) and spanning ~500 km of latitude in Mediterranean-type subalpine forest in California, USA. We used logistic regression to quantify differences in postfire regeneration between resident subalpine species and the seedling-only range (interpreted as climate-induced range extension) of montane species. We tested our assumption of increasing climatic suitability for montane species in subalpine forest using the predicted difference in habitat suitability at study plots between 1990 and 2030. We found that postfire regeneration of resident subalpine species was uncorrelated or weakly positively correlated with fire severity. Regeneration of montane species, however, was roughly four times greater in unburned relative to burned subalpine forest. Although our overall results contrast with theoretical predictions of disturbance-facilitated range shifts, we found opposing postfire regeneration responses for montane species with distinct regeneration niches. Recruitment of shade-tolerant red fir declined with fire severity and recruitment of shade-intolerant Jeffrey pine increased with fire severity. Predicted climatic suitability increased by 5% for red fir and 34% for Jeffrey pine. Differing postfire responses in newly climatically available habitats indicate that wildfire disturbance may only facilitate range extensions for species whose preferred regeneration conditions align with increased light and/or other postfire landscape characteristics.


Subject(s)
Pinus , Wildfires , Ecosystem , Fires , Forests , Seedlings , Trees
3.
Ecol Appl ; 31(3): e02280, 2021 04.
Article in English | MEDLINE | ID: mdl-33331069

ABSTRACT

Large, severe fires are becoming more frequent in many forest types across the western United States and have resulted in tree mortality across tens of thousands of hectares. Conifer regeneration in these areas is limited because seeds must travel long distances to reach the interior of large burned patches and establishment is jeopardized by increasingly hot and dry conditions. To better inform postfire management in low elevation forests of California, USA, we collected 5-yr postfire recovery data from 1,234 study plots in 19 wildfires that burned from 2004-2012 and 18 yrs of seed production data from 216 seed fall traps (1999-2017). We used these data in conjunction with spatially extensive climate, topography, forest composition, and burn severity surfaces to construct taxon-specific, spatially explicit models of conifer regeneration that incorporate climate conditions and seed availability during postfire recovery windows. We found that after accounting for other predictors both postfire and historical precipitation were strong predictors of regeneration, suggesting that both direct effects of postfire moisture conditions and biological inertia from historical climate may play a role in regeneration. Alternatively, postfire regeneration may simply be driven by postfire climate and apparent relationships with historical climate could be spurious. The estimated sensitivity of regeneration to postfire seed availability was strongest in firs and all conifers combined and weaker in pines. Seed production exhibited high temporal variability with seed production varying by over two orders of magnitude among years. Our models indicate that during droughts postfire conifer regeneration declines most substantially in low-to-moderate elevation forests. These findings enhance our mechanistic understanding of forecasted and historically documented shifts in the distribution of trees.


Subject(s)
Fires , Tracheophyta , Wildfires , Climate , Ecosystem , Forests , Seeds , Trees
4.
Gen Comp Endocrinol ; 294: 113497, 2020 08 01.
Article in English | MEDLINE | ID: mdl-32360542

ABSTRACT

In birds, exposure to exogenous testosterone during embryonic development can suppress measures of immune function; however, it is unclear whether these effects are due to direct or indirect action via aromatization. Estradiol (E2) is synthesized from testosterone by the enzyme aromatase, and this conversion is a necessary step in many signaling pathways that are ostensibly testosterone-dependent. Many lines of evidence in mammals indicate that E2 can affect immune function. We tested the hypothesis that some of the immunomodulatory effects observed in response to in ovo testosterone exposure in birds are mediated by conversion to E2 by aromatase, by using fadrozole to inhibit aromatization of endogenous testosterone during a crucial period of embryonic immune system development in domestic chickens (Gallus gallus). We then measured total IgY antibody count, response to PHA challenge, mass of thymus and bursa of Fabricius, and plasma testosterone post-hatch on days 3 and 18. Because testosterone has a reputation for immunosuppression, we predicted that if modulation of an immune measure by testosterone is dependent on aromatization, then inhibition of estrogen production by fadrozole treatment would lead to elevated measures of that parameter. Conversely, if testosterone inhibits an immune measure directly, then fadrozole treatment would likely not alter that parameter. Fadrozole treatment reduced circulating E2 in female embryos, but had no effect on males or on testosterone in either sex. Fadrozole-treated chicks had decreased day 3 plasma IgY antibody titers and a strong trend towards increased day 18 thymic mass. Furthermore, fadrozole treatment generated a positive relationship between testosterone and thymic mass in males, and tended to increase day 18 IgY levels for a given bursal mass in females. There was no effect on PHA response, bursal mass, or plasma testosterone at either age post-hatch. The alteration of several indicators of immune function in fadrozole-treated chicks implicates aromatization as a relevant pathway through which developmental exposure to testosterone can affect immunity in birds.


Subject(s)
Aromatase Inhibitors/pharmacology , Aromatase/metabolism , Chickens/immunology , Immunity/drug effects , Animals , Animals, Newborn , Bursa of Fabricius/drug effects , Bursa of Fabricius/immunology , Chickens/blood , Chickens/growth & development , Estradiol/blood , Fadrozole/pharmacology , Female , Immunoglobulins/blood , Male , Organ Size/drug effects , Phytohemagglutinins/pharmacology , Reproducibility of Results , Testosterone/blood , Thymus Gland/drug effects , Thymus Gland/immunology
5.
PLoS One ; 14(1): e0210766, 2019.
Article in English | MEDLINE | ID: mdl-30645624

ABSTRACT

A recent global trend toward retirement of farmland presents opportunities to reclaim habitat for threatened and endangered species. We examine habitat restoration opportunities in one of the world's most converted landscapes, California's San Joaquin Desert (SJD). Despite the presence of 35 threatened and endangered species, agricultural expansion continues to drive habitat loss in the SJD, even as marginal farmland is retired. Over the next decades a combination of factors, including salinization, climate change, and historical groundwater overdraft, are projected to lead to the retirement of more than 2,000 km2 of farmland in the SJD. To promote strategic habitat protection and restoration, we conducted a quantitative assessment of habitat loss and fragmentation, habitat suitability, climatic niche stability, climate change impacts, habitat protection, and reintroduction opportunities for an umbrella species of the SJD, the endangered blunt-nosed leopard lizard (Gambelia sila). We use our suitability models, in conjunction with modern and historical land use maps, to estimate the historical and modern rate of habitat loss to development. The estimated amount of habitat lost since the species became protected under endangered species law in 1967 is greater than the total amount of habitat currently protected through public ownership and conservation easement. We document climatic niche contraction and associated range contraction away from the more mesic margins of the species' historical distribution, driven by the anthropogenic introduction of exotic grasses and forbs. The impact of exotic species on G. sila range dynamics appears to be still unfolding. Finally, we use NASA fallowed area maps to identify 610 km2 of fallowed or retired agricultural land with high potential to again serve as habitat. We discuss conservation strategies in light of the potential for habitat restoration and multiple drivers of ongoing and historical habitat loss.


Subject(s)
Conservation of Natural Resources/methods , Desert Climate , Ecosystem , Agriculture , Animals , California , Climate Change , Endangered Species , Lizards , Models, Biological , Natural Resources , Phylogeography
6.
Psychiatr Psychol Law ; 26(3): 468-479, 2019.
Article in English | MEDLINE | ID: mdl-31984090

ABSTRACT

New Zealand's legislation mandates the inclusion of several legislative criteria to assist in the determination of defendants' fitness to stand trial (FTST). However, the unlegislated Presser criteria have been described as useful to discriminate between defendants' fitness without formal research to identify them as such. The sample consisted of 252 defendants' FTST forensic assessments between 2005 and 2015 with a mean age of 30.1 years, where 87.7% were male. Defendants were primarily from Maori descent (37.3%), New Zealand European (34.1%) and Pacific Island descent (17.9%). The authors found that all Presser and legislative criteria significantly predicted whether the defendant was fit to stand trial (FST). Both the Presser and legislative criteria have excellent area under the curve (AUC) statistics. However, the Presser criteria, compared to the legislative criteria, improved specificity of court judgements. The Presser criteria may therefore assist in correct FTST court decisions, particularly for borderline-fit defendants.

7.
PLoS One ; 12(8): e0181834, 2017.
Article in English | MEDLINE | ID: mdl-28854268

ABSTRACT

Contemporary climate change has been widely documented as the apparent cause of range contraction at the edge of many species distributions but documentation of climate change as a cause of extirpation and fragmentation of the interior of a species' core habitat has been lacking. Here, we report the extirpation of the American pika (Ochotona princeps), a temperature-sensitive small mammal, from a 165-km2 area located within its core habitat in California's Sierra Nevada mountains. While sites surrounding the area still maintain pikas, radiocarbon analyses of pika fecal pellets recovered within this area indicate that former patch occupancy ranges from before 1955, the beginning of the atmospheric spike in radiocarbon associated with above ground atomic bomb testing, to c. 1991. Despite an abundance of suitable rocky habitat climate warming appears to have precipitated their demise. Weather station data reveal a 1.9°C rise in local temperature and a significant decline in snowpack over the period of record, 1910-2015, pushing pika habitat into increasingly tenuous climate conditions during the period of extirpation. This is among the first accounts of an apparently climate-mediated, modern extirpation of a species from an interior portion of its geographic distribution, resulting in habitat fragmentation, and is the largest area yet reported for a modern-era pika extirpation. Our finding provides empirical support to model projections, indicating that even core areas of species habitat are vulnerable to climate change within a timeframe of decades.


Subject(s)
Climate Change , Ecosystem , Endangered Species , Lagomorpha , Animal Distribution , Animals , California , Carbon Radioisotopes/analysis , Lagomorpha/physiology , Temperature
8.
PLoS One ; 11(5): e0154838, 2016.
Article in English | MEDLINE | ID: mdl-27136458

ABSTRACT

Extreme weather events can provide unique opportunities for testing models that predict the effect of climate change. Droughts of increasing severity have been predicted under numerous models, thus contemporary droughts may allow us to test these models prior to the onset of the more extreme effects predicted with a changing climate. In the third year of an ongoing severe drought, surveys failed to detect neonate endangered blunt-nosed leopard lizards in a subset of previously surveyed populations where we expected to see them. By conducting surveys at a large number of sites across the range of the species over a short time span, we were able to establish a strong positive correlation between winter precipitation and the presence of neonate leopard lizards over geographic space. Our results are consistent with those of numerous longitudinal studies and are in accordance with predictive climate change models. We suggest that scientists can take immediate advantage of droughts while they are still in progress to test patterns of occurrence in other drought-sensitive species and thus provide for more robust models of climate change effects on biodiversity.


Subject(s)
Climate Change , Droughts , Animals , Endangered Species , Lizards , Population Dynamics , Weather
9.
Med Device Technol ; 17(2): 8-10, 12, 2006 Mar.
Article in English | MEDLINE | ID: mdl-16610711

ABSTRACT

A dynamic novel coating, consisting of a hydrophilic polymeric matrix and a bubbling agent, has been developed for precise entry and positioning of needles, and accurate collection of biopsy samples. These coated biopsy needles have been successfully used in in vitro trials. The results are discussed here. Potential application areas include vascular, cardiovascular and orthopaedics.


Subject(s)
Coated Materials, Biocompatible , Polymers , Ultrasonography/instrumentation , United States
10.
Environ Monit Assess ; 109(1-3): 73-80, 2005 Oct.
Article in English | MEDLINE | ID: mdl-16240190

ABSTRACT

Air pollution in the workplace environment due to industrial operation have been found to cause serious occupational health hazard. Similarly, heat stress is still most neglected occupational hazard in the tropical and subtropical countries like India. The hot climate augments the heat exposure close to sources like furnaces. In this study an attempt is made to assess air pollution and heat exposure levels to workers in the workplace environment in glass manufacturing unit located in the State of Gujarat, India. Samples for workplace air quality were collected for SPM, SO(2), NO(2) and CO(2) at eight locations. Results of workplace air quality showed 8-hourly average concentrations of SPM: 165-9118 microg/m(3), SO(2): 6-9 microg/m(3) and NO(2): 5-42 microg/m(3), which were below the threshold limit values of workplace environment. The level of CO(2) in workplace air of the plant was found to be in the range 827-2886 microg/m(3), which was below TLV but much higher than the normal concentration for CO(2) in the air (585 mg/m(3)). Indoor heat exposure was studied near the furnace and at various locations in an industrial complex for glass manufacturing. The heat exposure parameters including the air temperature, the wet bulb temperature, and the globe parameters were measured. The Wet Bulb Globe Temperature (WBGT), an indicator of heat, exceeded ACGIH TLVs limits most of the time at all the locations in workplace areas. The recommended duration of work and rest have also been estimated.


Subject(s)
Air Pollutants, Occupational/analysis , Hot Temperature , Occupational Exposure , Air Pollution/analysis , Carbon Dioxide/analysis , Dust/analysis , Environmental Monitoring , Glass , Humans , India , Nitrogen Dioxide/analysis , Sulfur Dioxide/analysis , Workplace
11.
Environ Monit Assess ; 109(1-3): 227-42, 2005 Oct.
Article in English | MEDLINE | ID: mdl-16240200

ABSTRACT

Air pollution has assumed gigantic proportion killing almost half a million Asians every year. Urban pollution mainly comprises of emissions from buses, trucks, motorcycle other forms of motorized transport and its supporting activities. As Asia's cities continue to expand the number of vehicles have risen resulting in greater pollution. Fugitive emissions from retail distribution center in urban area constitute a major source. Petrol vapours escape during refueling adding pollutants like benzene, toluene, ethylbenzene and xylene to ambient air. This paper discusses a study on fugitive emissions of Volatile Organic Compounds (VOC) at some refueling station in two metropolitan cities of India, i.e., Mumbai and Delhi. Concentration of VOCs in ambient air at petrol retail distribution center is estimated by using TO-17 method. Concentration of benzene in ambient air in Delhi clearly shows the effect of intervention in use of petroleum and diesel fuel and shift to CNG. Chemical Mass Balance (CMB) model is used to estimate source contributions. At Delhi besides diesel combustion engines, refueling emissions are also major sources. At Mumbai evaporative emissions are found to contribute maximum to Total VOC (TVOC) concentration in ambient air.


Subject(s)
Air Pollutants/analysis , Gasoline , Organic Chemicals/analysis , Cities , Environmental Monitoring , India , Vehicle Emissions , Volatilization
12.
Environ Monit Assess ; 96(1-3): 263-71, 2004.
Article in English | MEDLINE | ID: mdl-15327163

ABSTRACT

The present work attempts to identify VOC's in outdoor and indoor air in Mumbai City India. Ambient air was adsorbed on especially fabricated stainless steel cartridge packed with activated coconut charcoal at uniform flow rate. Qualitative identification of VOC's was done by thermally desorbing air from the cartridges and subsequent analysis on Varian GC-MS using NIST Library. The outdoor monitoring locations include residential area, commercial area, industrial, airport, petrol pumps, traffic junctions, arterial roads, highways, slums, parking area, service garages and municipal dump sites. The indoor locations comprised of air-conditioned and non air-conditioned offices, bedrooms, shops and instrumentation laboratory. The identified VOC's include aldehydes, ketones, polynuclear aromatic hydrocarbons, aromatic acids, oxygenated hydrocarbons, amines, esters and halogenated compounds. Thirteen VOCs in outdoor air and seven in indoor air amongst those identified, figure in the list of Hazardous Air Pollutants listed in Title III of the U.S. EPA Clean Air Act Amendments of 1990.


Subject(s)
Air Pollutants/analysis , Organic Chemicals/analysis , Gas Chromatography-Mass Spectrometry , India , Volatilization
13.
Br J Radiol ; 74(886): 955-8, 2001 Oct.
Article in English | MEDLINE | ID: mdl-11675315

ABSTRACT

Invasion of the major airways is a rare manifestation of respiratory tract involvement by Aspergillus sp. and is seen almost exclusively in immunocompromised patients. We present calcification as a new feature of this condition and its demonstration by ultrasound in a 15-year-old boy with severe neutropenia secondary to aplastic anaemia.


Subject(s)
Aspergillosis/complications , Aspergillosis/diagnostic imaging , Calcinosis/diagnostic imaging , Calcinosis/microbiology , Trachea/diagnostic imaging , Tracheal Diseases/microbiology , Adolescent , Amphotericin B/therapeutic use , Anemia, Aplastic/complications , Anemia, Aplastic/diagnostic imaging , Antifungal Agents/therapeutic use , Humans , Immunocompromised Host , Male , Neutropenia/complications , Neutropenia/diagnostic imaging , Trachea/microbiology , Tracheal Diseases/diagnostic imaging , Ultrasonography
14.
BMJ ; 322(7296): 1249, 2001 May 19.
Article in English | MEDLINE | ID: mdl-11388190
15.
Health Place ; 6(3): 159-69, 2000 Sep.
Article in English | MEDLINE | ID: mdl-10936772

ABSTRACT

In New Zealand, the process of deinstitutionalization is continuing to unfold as a specific manifestation of welfare state restructuring rather than as a discrete process within the health care sector. In this paper we consider the geography of mental health care in Auckland, New Zealand's only metropolitan city. Here, a highly fluid and competitive housing market has profoundly (re)shaped the opportunities for community care. We report on findings from a survey of representatives of the key agencies providing mental health care in central Auckland. We argue that the re-placing of mental health care into the community has often involved the separation of residential and treatment issues, to the detriment of the communities, institutions and (especially) individuals involved. We trace this fragmentation back to the primacy of the ideology of restructuring over the philosophy of deinstitutionalization. We build our argument around a discussion of the Mental Health (Compulsory Assessment and Treatment) Act 1992 and the apparent subordination of the Act to the emerging of a 'contract state' and broader legislation, such as the Resource Management Act 1991, the Privacy Act 1992 and the Commerce Act 1986, which underpins the re-regulation of New Zealand society.


Subject(s)
Community Mental Health Services/organization & administration , Contract Services/organization & administration , Deinstitutionalization/organization & administration , Housing , Geography , Health Policy , Humans , Models, Organizational , New Zealand , Organizational Case Studies
16.
Soc Sci Med ; 50(7-8): 1037-45, 2000 Apr.
Article in English | MEDLINE | ID: mdl-10714925

ABSTRACT

This paper examines the extensive restructuring of community-based long-term care that was initiated in Ontario, Canada in 1996, and does so with particular reference to longstanding problems of provision in rural communities. Specifically, it draws on a case study focussed on two small rural towns to develop a 'situated understanding' of service-user and service-provider perspectives on service coordination issues and on service cuts, particularly as they affect the ability of elderly people reliant on publicly-funded community services to stay in their homes, to continue to 'age in place'. The general and specific antecedents of long-term care reform are considered prior to the presentation of the case study. General antecedents include the rapid aging of Canada's population and aggressive strategies to reduce government deficits, while specific antecedents flow from a decade of failed attempts to address longstanding issues of service coordination and from the ideologically-driven, free market stance of the provincial government elected in 1995. The analysis of interviews conducted with 14 community-service users and 17 providers suggests that the managed competition system introduced as the centerpiece of long-term care reform has resulted in increasing diversity and uncertainty on both sides of the service provision equation. Despite continued attempts by rural elderly people and their families to 'cut and paste' support packages, it seems that the restructuring of publicly-funded community services, combined with a substantial re-investment in long-term care facilities, will make some elderly people more vulnerable to institutionalization.


Subject(s)
Community Health Services , Long-Term Care , Rural Health Services , Aged , Aged, 80 and over , Community Health Services/economics , Costs and Cost Analysis , Female , Health Care Reform , Humans , Long-Term Care/economics , Male , Ontario , Rural Health Services/economics
17.
Nucl Med Commun ; 20(6): 547-50, 1999 Jun.
Article in English | MEDLINE | ID: mdl-10451867

ABSTRACT

The colonic transit of an indium-111 enteric coated capsule was imaged with a gamma camera over a period of 3 days. The geometric centre of activity in the colon was calculated from regions drawn over four segments of the colon, plus a fifth segment as the estimated passed stool activity. Fifteen healthy subjects were scanned and the results analysed. The images were analysed by two observers to assess reproducibility of the geometric centre quantitative index (correlation, r = 0.985). In conclusion, although it can be difficult to identify the anatomical segments of the colon from the gamma camera images, by following a protocol with clear guidelines for ROI placement, good inter-observer reproducibility can be obtained.


Subject(s)
Colon/diagnostic imaging , Colon/physiology , Gastrointestinal Transit , Adult , Gamma Cameras , Humans , Indium Radioisotopes , Middle Aged , Observer Variation , Radionuclide Imaging , Reproducibility of Results , Tablets, Enteric-Coated
18.
Health Soc Care Community ; 7(1): 1-8, 1999 Jan.
Article in English | MEDLINE | ID: mdl-11560616

ABSTRACT

This paper provides a regional commentary on the progress of deinstitutionalization in an era of restructuring in New Zealand. The commentary focuses on the Waikato region, where the transition to community-based psychiatric care has been underway since the announcement of the closure of Tokanui Hospital in 1993. We use media reports to construct a narrative illuminating the distinctive threads of alternative discourse on the re-placing of people with mental health problems and sites of treatment 'into the community'. Our interpretation of this local narrative is cast against a series of backdrops: firstly, we provide an abbreviated history of deinstitutionalization in New Zealand; secondly, we examine mental health care as a sector within a rapidly evolving health system; and, thirdly, we reflect on the implementation of community mental health care in a re-regulated civil society. We argue that the effective implementation of community care has been hampered by the lack of concerted policy in the mental health care sector, by a fiscal squeeze on the health care system and by the impingement of non-health care legislation (the Commerce Act, the Privacy Act and the Resource Management Act) on the local expression and management of community care. In the Waikato narrative, we also identify administrative practices that have recast people with mental health problems as criminals and re-established prisons as the site of treatment. We conclude that the media in New Zealand have a role that extends beyond simply reporting on events. Indeed, the media act as a reflexive conduit; journalists interpret issues and through their 'stories' help to shape the course of events.

19.
J Cross Cult Gerontol ; 14(2): 153-68, 1999 Jun.
Article in English | MEDLINE | ID: mdl-14617890

ABSTRACT

The majority of China's population lives in rural areas and a pattern is emerging of very uneven provision of support for rural elderly people. Local economic conditions and broad demographic trends are creating diversity in the ability both of rural families to care for their elderly kin and in the capacity of communities to support their elderly residents and family carers. In part as a consequence of China's population policy and the 'one-child policy', future Chinese families will have fewer members and be 'older', but they will continue to be regarded emotionally and in policy as the main source of economic and social support for the elderly. The increasing involvement of women in the paid workforce and the changing geographical distribution of family members resulting from work-related migration, are reducing the ability of families to care for their elderly relatives. The availability of resources other than the family for the care of older persons therefore becomes a key issue. Communities in more prosperous, modernising rural areas are often able to provide their elderly residents with welfare and social benefits previously found almost exclusively in urban areas. However, in poorly developed rural areas, provision is either very patchy or non-existent and the local economy cannot support expansion or improvement. A case study in Zhejiang Province illustrates the favourable provision for ageing in a prosperous modernising rural community, in which entitled elderly residents are provided with an impressive array of financial and social benefits. The paper concludes with a consideration of the policy implications of the growing differentiation of the social and economic capacity of rural communities to support their elderly members.

20.
Eur J Nucl Med ; 25(11): 1524-30, 1998 Nov.
Article in English | MEDLINE | ID: mdl-9799349

ABSTRACT

Patient and organ motion is a potentially limiting factor in gamma camera single-photon emission tomography (SPET) imaging, as highlighted in stress thallium myocardial SPET, where the heart may exhibit a systematic axial motion (cardiac creep) following stress. Multi-rotation SPET has previously been described as a means of obtaining better raw data for motion detection and correction. This study describes the validation of a computerised motion detection algorithm applied to multi-rotation SPET, and reports measured motions in thallium myocardial stress SPET studies from a single-headed gamma camera. Forty-two patients underwent pharmacological stress (dipyridamole) with leg raising, with injection of 75 MBq thallium-201 and imaging after a 10-min delay to detect or evaluate coronary artery disease. Multi-rotation gamma camera SPET was performed with a single-headed gamma camera, with five sequential rapid (4.5 min) continuous SPET mode rotations over 180 degrees. A one-dimensional cross-correlation alignment technique was applied to the projection images to perform motion detection and correction in the axial direction prior to combining the five data sets for tomographic reconstruction. Validation of the cross-correlation alignment analysis was carried out by performing imaging with measured whole-body axial motions in nine subjects, and by reproducibility measurements on multi-rotation data sets. The effect of the applied motion correction was evaluated by calculating mean differences between image pairs before and after shifting, and the general reliability of the automatic motion detection was checked to within one pixel by visual assessment of 160 image pairs. Validation measurements of the cross-correlation technique gave a mean absolute error of 1.5+/-0.4 mm (0.24+/-0.06pixels) with a maximum error of 3.7 mm (0.6 pixels). In 40 subjects undergoing pharmacological stress 201Tl myocardial SPET imaging, the mean cardiac axial creep movement was calculated as 3.1+/-0.7 mm (0. 49+/-0.11 pixels), with 13 out of 40 (32%) having a calculated motion of 1 pixel (6.3 mm) or more. The automatic image shift was visually judged to be within 1 pixel in all 160 image pair analyses, and the mean pixel value difference between image pairs was reduced following image shifting. It is concluded that multi-rotation 180 degrees SPET imaging provides raw data which allow objective and accurate motion detection of cardiac motion in thallium stress myocardial imaging, whilst the one-dimensional cross-correlation technique demonstrates adequate accuracy and reliability to be applied as an automatic motion screening technique on these data.


Subject(s)
Heart/diagnostic imaging , Motion , Dipyridamole , Gamma Cameras , Humans , Image Processing, Computer-Assisted , Thallium Radioisotopes , Tomography, Emission-Computed, Single-Photon , Vasodilator Agents
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