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Biomedical subjects

A Abelson

Publications and source records attributed to A Abelson.

7 recordsLinked to original sources
PubMed2004

Deterioration Index (DI): a suggested criterion for assessing the health of coral communities.

The extensive deterioration of coral reefs worldwide highlights the importance of creating efficient monitoring methods to best assess their state of health. At present, several suggested parameters serve such indicators. None of these, however, is well accepted as reliably representing reef community health. In the present study we examine a new approach based on the ratio between mortality and recruitment rates of branching corals, which we term 'Deterioration Index' (DI). It aims at providing a quantitative indication of the state of health of reef-building coral communities. The method was developed and tested on 16 coral communities on artificially laid rocks along the coast of Eilat, Red Sea (Gulf of Aqaba). In contrast to frequently used indices (i.e. mortality rate, abundance and species richness), which did not demonstrate a consistent result in comparing disturbed vs. undisturbed coral communities, the DI revealed significant differences between these communities. Our results suggest that the use of the DI may enable the detection of disturbed coral communities in one instance monitoring, where the other parameters had failed. The DI, therefore, may provide a comparable quantitative assessment of the deterioration process and its intensity in a coral community. We propose the DI approach as an efficient and applicable tool for coral reef monitoring.

Animals↗
PubMed2002

The two sides of man-induced changes in littoral marine communities: Eastern Mediterranean and the Red Sea as an example.

Over the last two centuries, the marine life of the Eastern Mediterranean has been influenced by two major factors: one is beneficial, and concerns species migration, such as the opening of the Suez Canal, which enriched the impoverished eastern Mediterranean Sea with over 300 species of fish and invertebrates of Red Sea origin; while the other, a negative and possibly wider-reaching factor, is that of man-made pollution, which has induced unpredictable changes, destabilizing the biological world in both magnitude and duration. Initially cryptic, the effects caused by pollutants first occur at the biochemical and cellular levels of an organism, causing alterations and deviations from the normal, strongly mobilizing its defense systems. Conventional methodologies of ecological analyses, based on species and specimen numbers, cannot detect such alterations. Studying several mollusk populations from polluted and reference sites of the Red Sea and Mediterranean littoral of Israel, we used specific markers for in vivo and in vitro studies to expose the state of micronucleation; levels of defense transport systems such as membrane transport system of organic anions (SATOA) and organic cations (OCT); the state of the multi-xenobiotic resistance-mediating transporter (MXRtr). Based on fluorescent microscopy and microfluorometry, these markers offer powerful tools to expose cryptic changes in the affected populations and provide data necessary for planning and management to protect animal communities and preserve their biological diversity. Comparative analysis of general gene-expression in polluted and reference sites indicates that stress factors have differentially affected the various biological taxa and separated phenotypic sub-populations, producing a novel type of punctuated selection. Such factors, although negative in their influences, in some instances altering the qualities of organisms, and establishing alterations in their hereditary information, pre-adapt them to survive and succeed in new situations.

Adaptation, Physiological↗
PubMed1988

Complications of chiropractic treatment for back pain.

Back pain often causes patients great despair, and they expect the primary care physician or orthopedic surgeon to provide a quick, simple solution. Rest and analgesia are the most commonly prescribed treatments, and muscle relaxants, heat, traction, and physiotherapy are also used. If these treatments do not help, the patient may search for relief through faith healing, acupuncture, chiropractic treatment, or other nonconventional forms of treatment. Although chiropractic treatment is a popular alternative, its long-term effect is questionable and the medical literature contains numerous reports of patients whose condition worsened as a result of it. Physicians should be aware of the dangers of chiropractic treatment, particularly in patients with severe spondylitic changes, osteoporosis, fractures, tumors, ankylosing spondylitis, infections, or signs of nerve root pressure.

Back Pain↗
PubMed1978

Population structure in the Western Pyrenees: social class, migration and the frequency of consanguineous marriage, 1850 to 1910.

The effects of social class on migration distances and on the frequency of consanguineous marriages in Errazu, a Pyrenean village in Navarre, Spain, have been studied using data from parish records of baptisms and marriages, 1850-1910, and the census data for the year 1897. Migration distances are greater for tenants than for land-owners. Mean marital distances are not significantly different for the two social classes, but the movement of tenant families during married life results in significantly different parent-offspring distances for the two classes, at the 0.001 level for fathers and at the 0.002 level for mothers, by a t-test. Consanguineous marriages, up to and including third cousin marriages, are more frequent among land-owners (16.3 per cent) than among tenants (3.7 per cent). These frequencies are consistent with estimates based on the demographic characteristics of the population. Some implications of these results are discussed with reference to the findings of communities elsewhere in Europe and studies of communities in Japan. The implications of variation in the social class composition of populations with population density, for pedigree inbreeding values, are also considered.

Consanguinity↗