Biomedical subjects

John B Davies

Publications and source records attributed to John B Davies.

7 recordsLinked to original sources

PubMed2005

Encoding during the attentional lapse: accuracy of encoding during the semantic sustained attention to response task.

An experiment investigated the relationship between the ability to encode verbal stimuli during an attentional lapse. The task employed a variation on the sustained attention to response task (SART, Robertson, Manly, Andrade, Baddeley, & Yiend, 1997) which involved the detection of an infrequent target against a background of words. As a manipulation, participants were either instructed to encode the stimuli or were merely exposed to the stimuli. Retrieval was measured using process dissociation. Irrespective of the instructions given to the participants during the task, participants were more likely to retrieve information on the basis of recollection after an error was made than before, whilst the likelihood of retrieving information on the basis of familiarity remained invariant over the same period. The implications of this result for methods of investigating subjective experience are discussed.

Adult↗

PubMed2005

Variability in lay perceptions of depression: a vignette study.

This paper describes a study investigating lay perceptions of depression in terms of perceived severity. Students (N = 128) were presented with vignettes describing individuals with symptoms of depression based on DSM-IV. The descriptions were varied in terms of gender, social status, and a self-referent manner of communicating depressive symptomatology. Participants were asked to rate the degree to which vignette characters were thought to be depressed on a Likert-type scale. Results indicate that a non-self-referent style of communicating depressive symptoms by female vignette characters was seen as an indication of elevated levels of depression, and these findings are discussed with reference to the literature.

Adult↗

PubMed2004

An exploration of street drinking in Drumchapel, Scotland.

This paper describes the results of a survey undertaken to contribute to a health needs assessment of persistent street drinkers in Drumchapel, Greater Glasgow. Street drinkers, members of the public and local service providers [including agency professionals (community workers; health workers; social workers) and others (e.g. shopkeepers)] were interviewed. Street drinkers were generally male, single, unemployed and living in their own (rented) accommodation. Not being homeless, they gave volitional reasons for drinking in the street, centred on social aspects and the cost of drinking in traditional establishments/public houses. Half the group said they did not do all their drinking on the street, suggesting alternatives may be possible. Uptake of food offered to respondents being interviewed was low, and self-reported diet was poor in vitamins and unvaried. Awareness of services was low in the street drinking group, with friends/family remaining the most common source of support. Public concern was mainly with the visibility of the group and the negative impact this was perceived to have on the community; however, service providers focused on health risks associated with street drinking. Consensus on the need for some accommodation/centre for drinkers with access to services was established across all groups.

Adult↗

PubMed2004

Subjective experience and the attentional lapse: task engagement and disengagement during sustained attention.

Three experiments investigated the relationship between subjective experience and attentional lapses during sustained attention. These experiments employed two measures of subjective experience (thought probes and questionnaires) to examine how differences in awareness correspond to variations in both task performance (reaction time and errors) and psycho-physiological measures (heart rate and galvanic skin response). This series of experiments examine these phenomena during the Sustained Attention to Response Task (SART, Robertson, Manly, Adrade, Baddeley, & Yiend, 1997). The results suggest we can dissociate between two components of subjective experience during sustained attention: (A) task unrelated thought which corresponds to an absent minded disengagement from the task and (B) a pre-occupation with one's task performance that seems to be best conceptualised as a strategic attempt to deploy attentional resources in response to a perception of environmental demands which exceed ones ability to perform the task. The implications of these findings for our understanding of how awareness is maintained on task relevant material during periods of sustained attention are discussed.

Adult↗

PubMed2003

Delivery of several forms of DNA, DNA-RNA hybrids, and dyes across human sclera by electrical fields.

PURPOSE: Iontophoresis has been used for drug delivery across the cornea for many years. We sought to test whether small charged dyes and DNA can be transferred across human sclera by an electric field. METHODS: Full-thickness human scleral fragments were embedded vertically in an agarose gel and positioned to completely span individual gel lanes. The scleral fragments were located approximately 1 cm downstream from the gel wells. DNA or dyes were loaded into the wells and electrophoresis was carried out at about 3.3 V/cm for approximately 2 h per run. Movement of DNA and dyes through the agarose and sclera was measured with either digital time-lapse photography or through DNA extraction and purification from the gel. SYBR green stain was used as a sensitive method to detect DNA. RESULTS: Digital time-lapse photography of agarose gel electrophoresis revealed that two dyes, xylene cyanol and bromphenol blue, passed through the sclera in the presence of an electric field. Xylene cyanol was driven through the sclera virtually unimpeded except for some spreading of the dye. Bromphenol blue was slowed markedly by the sclera, but it too eventually passed through the tissue. Small DNAs, including a single stranded 51-mer and a double hairpin 68-mer oligonucleotide, passed through the sclera as detected by SYBR green staining. Linear double stranded DNAs ranging from 50 bp to 12,000 bp passed through the sclera. The larger the DNA, the slower the rate of passage through the sclera, and the greater the band spreading. pEGFP-1 (a 3 kb plasmid) passed through the sclera but was accompanied by a great amount of band spreading. Following completion of the initial electrophoresis run, the plasmid DNA was extracted from the smeared bands in the agarose distal to the sclera and re-run on a second gel without sclera. The initially smeared plasmid bands resolved into 2 distinct bands after extraction and purification and matched well with control plasmid bands. CONCLUSIONS: Charged molecules such as xylene cyanol, bromphenol blue, and DNAs ranging from 51 bp oligonucleotides to a 3 kb plasmid can be driven across human sclera by an electric field and directly detected. Passage of plasmids was efficient, but the plasmid bands were diffuse after transit. This technique offers promise as a noninvasive DNA delivery tool, where gene therapy can be accomplished by small RNA or DNA synthetic oligonucleotides, larger double stranded fragments, or even plasmids.

Adolescent↗

PubMedDate not supplied

An alternative method for predicting attrition from an alcohol treatment programme.

AIMS: To test the predictive validity of a vignette methodology based on a Signal Detection model by examining treatment attrition within an alcohol clinic. METHODS: Participants were asked to categorize vignettes that described individuals drinking alcohol as problem or nonproblem alcohol use at the beginning of a 4-week intensive course of treatment. These participants were divided retrospectively into two groups: those who completed treatment and those who dropped-out of treatment. A matched post-treatment long-term abstainer group was also tested. RESULTS: Signal Detection analyses demonstrated that response bias scores predicted who would drop out of treatment (P = 0.01). CONCLUSIONS: The vignette methodology provided useful levels of prediction in an applied clinical setting. It was argued that verbal reports from problem alcohol users may be more usefully conceptualized in terms of sensitivity and response bias than in terms of memory or 'truth'.

Adult↗

PubMedDate not supplied

Alcohol consumption, perceptions of community responses and attitudes to service provision: results from a survey of Indian, Chinese and Pakistani young people in Greater Glasgow, Scotland, UK.

AIMS: To gather prevalence data regarding alcohol consumption and gauge perceptions of community responses to alcohol and service provision in a sample of Pakistani, Indian and Chinese young people aged 16-25 years, in Greater Glasgow, Scotland, UK. METHODS: A survey methodology utilizing purposive sampling techniques (n = 174) was employed. Data were collected using an interviewer-administered questionnaire. RESULTS: Alcohol consumption amongst the target populations is currently lower than that of the general population. Predictors of alcohol consumption were found to include self-reported importance of religion (a negative association with consumption) and having same-ethnicity friends who drink alcohol. There was a lack of consensus amongst participants regarding whether service provision should be part of the mainstream or specialist for black and minority ethnic individuals. CONCLUSIONS: Alcohol consumption in the target populations may be increasing and service provision could benefit by including specialist services for black and minority ethnic groups, in addition to mainstream services that need to be culturally sensitive.

Adolescent↗