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A Borja

Publications and source records attributed to A Borja.

11 recordsLinked to original sources
PubMed2006

Maximum likelihood mixture estimation to determine metal background values in estuarine and coastal sediments within the European Water Framework Directive.

Some of the recently derived European Directives, such as the Water Framework and Marine Strategy, have, as ultimate aims, to achieve concentrations of hazardous substances in the marine environment near background values. Hence, the determination of natural background levels, in marine sediments, is highly relevant. The present study proposes the use of the maximum likelihood mixture estimation (MLME) to determine regional background levels and upper threshold of metal concentration, with the Basque Country as a case study (with a data set of 575 samples, from estuarine and littoral areas, including both intertidal and subtidal sediments). The heuristic procedure is applied with unimodal data distributions (Cd, Cr, Fe and Ni) and the mixture density estimations, based upon maximum likelihood, are carried out with polypopulational data distributions (As, Cu, Mn, Hg, Pb and Zn). The upper limits of the distribution are proposed, as the limits between 'High Status' and 'Good Status' (according to the Water Framework Directive terminology). The regional upper limits were 0.45 microg g(-1) for Cd, 71 microg g(-1) for Cr, 53,542 microg g(-1) for Fe, 57 microg g(-1) for Ni, 24 microg g(-1) for As, 64 microg g(-1) for Cu, 447 microg g(-1) for Mn, 0.27 microg g(-1) for Hg, 66 microg g(-1) for Pb, and 248 microg g(-1) for Zn. The results from this study can assist further in the determination of sediment reference conditions, to assess chemical status, within the above-mentioned directives; likewise, it will be studied as a useful methodology in determining regional metal backgrounds in other European countries.

Arsenic↗
PubMed2005

Assessing reference conditions and physico-chemical status according to the European Water Framework Directive: a case-study from the Basque Country (Northern Spain).

The European Water Framework Directive requires the development of new and accurate methodologies, addressing the assessment of the physico-chemical status of transitional and coastal waters; these are considered by the Directive as the supporting elements for the final evaluation of the Ecological Quality Status. This contribution develops new approaches in the determination of the physico-chemical status, solving some problems detected in previous contributions, i.e.: (a) fitting the classification of water bodies and typologies, by means of the stretching of the typologies, according to the natural salinity gradient of types; (b) defining reference conditions, based upon the new approach to typologies, (c) proposing accurate multivariate methodologies, in determining the physico-chemical status of the transitional and coastal waters, based upon the defined typologies and references; and (d) discussion of the results obtained by reference to methodological aspects and water quality evolution in the Basque Country, Spain (as a case-study), during the last decade.

Cluster Analysis↗
PubMed2003

The application of a Marine Biotic Index to different impact sources affecting soft-bottom benthic communities along European coasts.

Following the European Water Framework Directive (2000/60/EC), the authors proposed, in a previous contribution, a Marine Biotic Coefficient (BC) to establish the ecological quality of soft-bottom benthos within European estuarine and coastal environments. The present study examines the application of the BC to the Atlantic (North Sea; Bay of Biscay; South of Spain) and Mediterranean (Spain and Greece) European coasts. The investigation assesses also the usefulness of the BC, in relation to different impact sources (e.g. drilling cuts with ester-based mud, submarine outfalls, heavy metals, industrial and mining wastes, jetties and sewerage works). The results obtained are consistent with those obtained using several methods and parameters, such as richness, diversity, evenness, Abundance-Biomass comparison plots and univariate and multivariate statistical analyses. The BC values provide a simple and clearly defined way to establish the ecological quality of soft-bottom benthos, complementary to the above mentioned methods.

Animals↗
PubMed2001

[Intraoral non-Hodgkin's lymphoma. Presentation of 4 clinical cases].

The non-Hodgkin lymphomas (NHL) represent an heterogeneous group of malignancies of lymphoreticular histogenesis. In most cases, they initially arise within lymph nodes but so-called extranodal lymphomas are also found. The NHL has low incidence in the oral cavity. It may involve bone and/or soft tissues as a primary or secondary manifestation. We present a review of the literature and four clinical cases of intraoral NHL. The first couple of cases are primary forms, the third one is associated to HIV infection and the last one is an oral presentation as a component of more widely disseminated disease.

Adult↗
PubMed1991

Bone marrow transplantation in sickle cell anaemia.

Sickle cell anaemia is still responsible for severe crippling and death in young patients living in developing countries. Apart from prophylaxis and treatment of infections, no active treatment can be safely proposed in such areas of the world. Therefore a bone marrow transplantation was performed in 12 patients staying in Belgium and planning to return to Africa. Twelve patients, aged between 11 months and 23 years (median 4 years), underwent a HLA identical bone marrow transplantation. The conditioning regimen included oral busulphan for four consecutive days (4 mg/kg) followed by four days of intravenous cyclophosphamide (50 mg/kg). In 10 patients the engraftment was rapid and sustained. A further patient suffered transient red cell hypoplasia and another underwent a second bone marrow transplantation from the same donor at day 62 because of graft rejection. All patients are alive and well with a follow up ranging from 9-51 months (median 27 months). In all cases a complete cessation of vaso-occlusive episodes and haemolysis was observed as was a change in the haemoglobin pattern in accordance with the donor's electrophoretic pattern.

Adolescent↗