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M L Griffiths

Publications and source records attributed to M L Griffiths.

13 recordsLinked to original sources
PubMed2000

Concentrations of suspended particulate organic carbon in the tidal Yorkshire Ouse River and Humber Estuary.

Data are presented for particulate organic carbon (POC) and particulate nitrogen (PN) concentrations in the Humber Estuary and tidal River Ouse Estuary. The POC data were derived from approximately monthly surveys and are consistent with data reported for suspended particulate matter (SPM) in the non-tidal River Ouse (the freshwater river) and with SPM, or bed sediments, in estuarine ecosystems such as the Mississippi, Delaware, San Francisco Bay, Tolo Harbour, the Vellar Estuary and Cochin Backwater, as well as the Loire, Gironde, Ems and Tamar Estuaries. Relative to the dry weight of SPM, the Humber-averaged organic carbon and nitrogen percentages during the year February 1995-March 1996 were 2.6 +/- 0.6% (mean and S.D.) and 0.21 +/- 0.04%, respectively. The ratio of Humber-averaged POC to Humber-averaged PN was 13 +/- 3. Higher POC levels were observed near the Humber's mouth and in the adjacent coastal zone during 'bloom' conditions, and in the upper estuarine reaches during large, winter and springtime freshwater inflows. At these times of high runoff, the POC content of SPM increased progressively up-estuary from the coastal zone to the tidal River Ouse. When inflows became very low, during late spring to early autumn of 1995, both the freshwater-saltwater interface (FSI) and the strengthening turbidity maximum (TM) moved further up-estuary and the POC content of SPM in the upper reaches of the Ouse became lower compared with that immediately down-estuary. This led to a poorly defined POC maximum near the confluence of the Humber, Ouse and Trent, before POC eventually decreased again towards the coastal zone. The lower POC contents in the upper estuarine reaches of the tidal Ouse may have been partly due to POC respiration by heterotrophic bacteria attached to SPM within the TM, consistent with the severe oxygen depletion observed there during high turbidity, summertime spring tides.

Carbon↗
PubMed2000

Seasonal variability of salinity, temperature, turbidity and suspended chlorophyll in the Tweed Estuary.

Results are presented from a campaign of measurements that were undertaken to examine seasonal variability in physical and chemical fluxes and processes within the Tweed Estuary during the period September 1996-August 1997. The study utilised monthly surveys, each of approximately 1 week duration. This article interprets a subset of the salinity, temperature, turbidity [suspended particulate matter (SPM) levels] and chlorophyll a data. Measurements discussed here were obtained throughout the estuary during high-speed transects that covered the region between the tidal river and the coastal zone. Longitudinal distributions of surface salinity depended strongly on freshwater runoff. During high runoff the surface salinity was low and the freshwater-saltwater interface (FSI) was located close to the mouth. The reverse was true at times of low runoff. Salinity stratification was generally strong. During the surveys, river runoff temperatures ranged from approximately 2 to 18 degrees C and coastal waters (approximately 33 salinity) from approximately 6 to 15 degrees C. Turbidity was low throughout the campaign (SPM < 30 mg l(-1)). Because of rapid flushing times (one or two tides), turbidity tended to mix conservatively between river and coastal waters. Higher coastal turbidity was associated with stronger wind events, and higher fluvial turbidity with spate events. Suspended chlorophyll a levels were usually low throughout the estuary (typically < 2 microg l(-1)) and showed large spatial variability. Because of the rapid flushing of the estuary, it is hypothesised that it was not possible for several algal cell divisions to occur before algae were flushed to the coastal zone. A 'bloom' occurred during the May 1997 survey, when chlorophyll a levels reached 14 microg l(-1). Higher chlorophyll a concentrations at that time occurred at very low salinities, indicating that these waters and algae were largely fluvially derived, and may have resulted from increasing springtime solar irradiation.

Chlorophyll↗
PubMed1987

Phenytoin overdose.

Explore the source record for details and available documents.

Administration, Oral↗
PubMed1985

Causes of death in a rural hospital in 1983.

All 749 deaths recorded by a rural hospital during 1983 were listed in five age groups according to the 9th revision of the International Classification of Diseases. The largest number of deaths were in adults aged 50 years and over and in children aged under 2 years, and the most frequent causes of death were malnutrition, hypertension, prematurity, heart failure and gastro-enteritis.

Adolescent↗
PubMed1981

A comparison of admissions to a semirural hospital between the years 1959/1960 and 1977/1978.

A survey was conducted of admissions to a semirural hospital for Black patients in Bophuthatswana for the period April - March of the years 1959/19610 and 1977/1978 to ascertain whether any measurable change had occurred in the disease pattern. No significant increase over the 18 years was found in the number of admissions for diabetes, appendicitis, peptic ulceration, or coronary heart disease. There was, however, an increase in the incidence of anorectal conditions and in admissions for hypertension.

Adolescent↗
PubMed1981

Tuberculosis management in a rural community -- factors in failure.

An investigation was carried out during 1978 to establish the proportion of tuberculosis patients who had a relapse or whose treatment had failed and who presented together with new patients with smear-positive pulmonary tuberculosis at a regional hospital. Reasons for the high number of previously treated patients found in this study (35.8%) are discussed, and include the inadequate experience of the health team in tuberculosis, non-compliance of patients and geographical factors. The hospital-centered comprehensive health scheme seems to offer advantages over the district surgeon scheme in the organization of an adequate tuberculosis programme in a country area.

Adolescent↗