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Selected AbstractsThe effect of sward structure as influenced by ryegrass genotype on bite dimensions and short-term intake rate by dairy cowsGRASS & FORAGE SCIENCE, Issue 1 2003P. D. Barrett Abstract The effects of genotypic variation in ryegrasses on sward structure, bite dimensions and intake rate by dairy cows were investigated. Two experiments were conducted. In Experiment 1, swards were in a vegetative state whereas, in Experiment 2, they were partly reproductive and were taller with higher herbage mass but lower leaf proportion than in Experiment 1. Applicability of relationships between sward structure and bite characteristics, previously established from artificial or hand-constructed swards, to field conditions were tested. Additional short-term intake rates and/or sward structural characteristics were considered as indicators of potential intake for use in protocols for the evaluation of grass varieties. Four cultivars were studied: AberElan, Twins (diploid and tetraploid perennial ryegrasses respectively), Polly, a hybrid ryegrass (perennial × Italian ryegrass) and Multimo (Italian ryegrass), each established in 200-m2 plots in four replicated blocks. Herbage intake rate was determined by short-term liveweight change (taking account of insensible weight loss) using 16 dairy cows allocated to four balanced groups with each plot grazed by one group for a 1-h assessment period. One block was grazed per day, over a 4-d experimental period, with each group grazing each variety in a complete crossover design. Sward characteristics and bite rate were also measured in both experiments. Bite dimensions were subsequently estimated, with bite depth being determined as a function of extended tiller height (ETH) in both experiments. Within both experiments, bite mass and intake rate did not differ significantly between swards of different cultivars despite swards containing Multimo generally having a higher ETH and water-soluble carbohydrate concentration and lower green leaf mass, sward bulk density and neutral-detergent fibre concentration than the other swards. However, bite depth was significantly higher (P < 0·01) in swards containing Multimo swards than in the others and, in Experiment 1, bite depth, as a proportion of ETH, was higher in swards containing Multimo and lower in those containing Twins than in the other two cultivars, whereas there was no difference in Experiment 2. Taking both experiments together, the mean bite depth was 0·5 of ETH with sward bulk density accounting for almost half the variance in the relationship between bite depth and ETH. The bulk density of the bite (bite mass per unit bite volume), measured in Experiment 2, followed a similar pattern to sward bulk density, increasing in the order Multimo, Polly, AberElan and Twins. It is concluded that the relationships between sward characteristics and bite dimensions, derived from artificial swards, are applicable to field swards, although the range in natural ryegrass sward characteristics is usually not as wide as in experiments using artificial swards. Lack of precision in the measurement of short-term intake and in sward-based measurements is likely to preclude their use in the evaluation of grass varieties. [source] Rain forest invasion of eucalypt-dominated woodland savanna, Iron Range, north-eastern Australia: II.JOURNAL OF BIOGEOGRAPHY, Issue 8 2004Rates of landscape change Abstract Aim, To explore rates of rain forest expansion and associated ecological correlates in Eucalyptus -dominated woodland savanna vegetation in north-eastern Australia, over the period 1943,91. Location, Iron Range National Park and environs, north-east Queensland, Australia. This remote region supports probably the largest extent of lowland (< 300 m) rain forest extant in Australia. Rainfall (c. 1700 mm p.a.) occurs mostly between November and June, with some rain typically occurring even in the driest months July,October. Methods, Interpretation of change in lowland rain forest vegetation cover was undertaken for a 140 km2 area comprising complex vegetation, geology and physiography using available air photos (1943, 1970 and 1991). A GIS database was assembled comprising rain forest extent for the three time periods, geology, elevation, slope, aspect, proximity to streams and roads. Using standard GIS procedures, a sample of 6996 10 × 10 m cells (0.5% of study area) was selected randomly and attributed for vegetation structure (rain forest and non-rain forest), and landscape features. Associations of rain forest expansion with landscape features were examined with logistic regression using the subset of cells that had changed from other vegetation types to rain forest, and remained rain forest over the assessment period, and comparing them with cells that showed no change from their original, non-rain forest condition. Results, Rain forest in the air photo study area increased from 45 km2 in 1943 to 78.1 km2 by 1970, and to 82.6 km2 by 1991. Rainfall (and atmospheric CO2 concentration) was markedly lower in the first assessment period (1943,70). Modelled rates of rain forest invasion differed predominantly with respect to substrate type, occurring faster on substrates possessing better moisture retention properties, and across all elevation classes. Greatest expansion, at least in the first assessment period, occurred on the most inherently infertile substrates. Expansion was little constrained by slope, aspect and proximity to streams and roads. On schist substrates, probability of invasion remained high (> 60%) over distances up to 1500 m from mature rain forest margins; on less favourable substrates (diorite, granites), probability of expansion was negligible at sites more than 400 m from mature margins. Main conclusions, (i) Rain forest expansion was associated primarily with release from burning pressure from c. the 1920s, following major disruption of customary Aboriginal lifestyles including hunting and burning practices. (ii) Decadal-scale expansion of rain forest at Iron Range supports extensive observations from the palaeoecological literature concerning rapid rain forest invasion under conducive environmental conditions. (iii) The generality of these substrate-mediated observations requires further testing, especially given that landscape-scale rain forest invasion of sclerophyll-dominated communities is reported from other regions of north-eastern Australia. [source] The effect of rizatriptan, ergotamine, and their combination on human peripheral arteries: a double-blind, placebo-controlled, crossover study in normal subjectsBRITISH JOURNAL OF CLINICAL PHARMACOLOGY, Issue 1 2002Peer Tfelt-Hansen Aims, To compare the peripheral vasoconstrictor effects of ergotamine, rizatriptan, and their combination, in normal subjects. Methods, This was a double-blind, four-way, crossover study. Sixteen young male volunteers, selected as responders to the vasoconstrictor effect of 0.5 mg ergotamine i.v., were administered 10 mg oral rizatriptan, 0.25 mg i.v. ergotamine, 10 mg oral rizatriptan+0.25 mg i.v. ergotamine, and placebo. The vasoconstrictor effect on peripheral arteries was measured with strain gauge plethysmography up to 8 h after dosing. The 8 h assessment period was divided into two 4 h intervals to assess the immediate (0,4 h) vs sustained effect (4,8 h) of treatment. Results, For the 0,4 h interval, the decreases in peripheral systolic blood pressure gradients were: placebo (,1 mmHg [95% CI: ,3, 1]) Diagnoses at the first psychotic episode and cognitive functioningACTA PSYCHIATRICA SCANDINAVICA, Issue 2002J. Addington Objectives, To determine the relationship between diagnosis and cognitive functioning in a first-episode sample. Methods, 175 subjects were diagnosed (SCID) on admission to a comprehensive treatment programme for early psychosis and 1 year later. Symptoms (PANSS), social functioning and cognitive functioning (using a comprehensive cognitive battery) were assessed initially and at 1 year. Subjects were divided into three groups: (1) Stable diagnosis of schizophrenia over 1 year (n=84). (2) Initial diagnosis of schizophreniform, brief psychotic disorder, substance induced psychosis or psychosis NOS but who met criteria for schizophrenia at 1 year (n=49) and (3) Stable diagnosis over 1 year of schizophreniform, brief psychotic disorder, substance induced psychosis or psychosis NOS (n=44). Results, There were significant differences amongst the three groups at both assessment periods in positive and negative symptoms and social functioning. There were no differences amongst the groups in cognitive functioning. Conclusions, Individuals with psychotic disorders who do not go on to develop schizophrenia do not differ significantly in neurocognition from those who do develop schizophrenia, although they may have advantages in other areas. [source] Social integration in young adulthood and the subsequent onset of substance use and disorders among a community population of urban African AmericansADDICTION, Issue 3 2010Kerry M. Green ABSTRACT Aims This paper examines the association between social integration in young adulthood and the later onset of substance use and disorders through mid-adulthood. Design Data come from a community cohort of African Americans followed longitudinally from age 6,42 years with four assessment periods. Setting The cohort all lived in the Woodlawn neighborhood of Chicago in 1966, an urban disadvantaged setting. Participants All Woodlawn first graders in 1966 were asked to participate; 13 families declined (n = 1242). Measurement Substance use was measured via interview at age 42 and includes the onset of alcohol and drug use disorders and the onset of cocaine/heroin use between ages 32 and 42 years. Social integration measures were assessed via interview at age 32 and include social roles (employee, spouse, parent), participation in religious and social organizations and a measure of overall social integration. Control variables were measured in childhood and later in the life course. Findings Multivariate regression analyses suggest that unemployment, being unmarried, infrequent religious service attendance and lower overall social integration in young adulthood predict later adult-onset drug use disorders, but not alcohol use disorders once confounders are taken into consideration. Unemployment and lower overall social integration predict onset of cocaine/heroin use later in adulthood. Conclusions Results show meaningful onset of drug use and substance use disorders during mid-adulthood and that social integration in young adulthood seems to play a role in later onset of drug use and drug disorders, but not alcohol disorders. [source] Effects of a multi-vitamin/mineral supplement on cognitive function and fatigue during extended multi-tasking,HUMAN PSYCHOPHARMACOLOGY: CLINICAL AND EXPERIMENTAL, Issue 6 2010Crystal F. Haskell Abstract Objectives A significant minority of the population consume multi-vitamins/minerals for their putative health benefits, including potentially beneficial effects on cognitive performance, fatigue and mood. The current study investigated the effect of supplementation with a multi-vitamin/mineral on fatigue and cognitive function in healthy females. Methods In this placebo-controlled, double blind, randomized, parallel groups trial the effect of a multi-vitamin/mineral (Supradyn®) was assessed in 216 females aged 25,50 years. Participants attended the laboratory before and 9 weeks after commencing treatment. During both visits cognitive function and the modulation of task related mood/fatigue were assessed in two discrete 20-min assessment periods during which participants completed a four-module version of the Multi-Tasking Framework. Results Those in the vitamin/mineral group exhibited an attenuation of the negative effects of extended task completion on mood/fatigue. Multi-tasking performance for this group was also improved in terms of accuracy across all tasks, and on two of the individual tasks (Mathematical Processing and Stroop) in terms of both faster and more accurate responses. Analysis of a subsection (N,=,102) demonstrated significant reductions in homocysteine levels following the vitamins/mineral supplement. Conclusions These findings suggest that healthy members of the general population may benefit from augmented levels of vitamins/minerals via direct dietary supplementation. Copyright © 2010 John Wiley & Sons, Ltd. [source] Parent , Adolescent Relationships and Girls' Unhealthy Eating: Testing Reciprocal EffectsJOURNAL OF RESEARCH ON ADOLESCENCE, Issue 4 2002Andrea Bastiani Archibald This longitudinal study tested the direction of associations between parent ,adolescent relationships and adolescent girls' unhealthy eating. Girls (N= 184) were seen at Time 1 (M age = 14.30 years), and then again 2 years later (Time 2; M age = 16.04 years). At both assessment periods, they completed measures that assessed their eating attitudes and behaviors, relationships with their parents, height, weight, and age of menarche. Whereas unhealthy family relationships have been hypothesized as a precursor to unhealthy eating attitudes and behaviors, it is also possible that increases in these behaviors contribute to more negative relationships within the family. Structural equation modeling was employed to simultaneously investigate the longitudinal influence of parent , adolescent relationships on girls' unhealthy eating, and girls' unhealthy eating on parent , adolescent relationships. The model was tested with the following controls: body mass (kg/m2), pubertal timing and age. A longitudinal direct effect was found for unhealthy eating on parent, adolescent relationships; however, no direct effect was found for parent, adolescent relationships on unhealthy eating over time. For middle, and late,adolescent girls, it appears that unhealthy eating behaviors and attitudes are predictive of less positive parent , adolescent relationships over time. [source] Dental Erosion: In Vitro Model of Wine Assessor's ErosionAUSTRALIAN DENTAL JOURNAL, Issue 4 2001Tong Bee Mok Background: Wine makers and assessors frequently experience severe dental erosion. The objectives of this study were to develop an in vitro model of dental erosion caused by frequent wine contact with teeth, and to use this model to assess the effectiveness of a variety of methods which might protect against this form of erosion. Methods: An initial pilot study found that riesling style wine was more erosive than champagne style, and both more than claret. Wine tasting was simulated by subjecting exposed windows of enamel and root surfaces on 50 intact, extracted human teeth to 1400 one minute exposures to white wine (pH 3.2). A variety of dental materials were applied to the exposed windows on groups of teeth prior to erosive challenge, to assess their protective ability. Results: Protective resin coatings and fluoride varnishes protected both enamel and roots against wine induced erosion. A high degree of protection was provided by APF gel, with less by NaF gel. Conclusions: It was concluded that dentists may be able to help minimise erosion resulting from frequent wine-tasting in their patients by the clinical application of one or a combination of these agents at times prior to prolonged assessment periods. [source] Patients' Evaluation of Two Occlusal Schemes for Implant OverdenturesCLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 3 2008BHealSc, John M. Aarts BEd, MhealSc, PGDipCDTech ABSTRACT Background: There is an absence of conclusive evidence for occlusal schemes in implant overdentures. Purpose: To investigate the consequences of two different occlusal schemes on levels of satisfaction for patients wearing implant overdentures. Materials and Methods: Within an existing randomized controlled clinical trial, a physiologic occlusal scheme was compared with a lingualized occlusal scheme for 18 selected participants all with implant overdentures. Nine participants had conventional maxillary complete dentures opposing mandibular 2-implant overdentures; a further nine participants had maxillary 3-implant overdentures opposing mandibular 2-implant overdentures. All participants recruited had been wearing their original prostheses for 3 years with a bilateral balance occlusal scheme. The participants' existing satisfaction levels, as a baseline, were determined using visual analogue scale questionnaires. They were followed by similar assessments of two further occlusal schemes using 2-month assessment periods. On completion of the study, the participants selected their preferred occlusal scheme and semiformal interviews were conducted to assess the rationale for their choices. Results: Baseline data showed all the participants had pre-existing high satisfaction levels. Thereafter, of those participants that received lingualized occlusion first, 55.6% reported that the physiologic occlusion was better than lingualized occlusion. For those participants who received the physiologic occlusion first, 85.7% reported that physiologic occlusion was better than lingualized occlusion. On completion of the study, 64.7% of the participants preferred the physiologic occlusion, 35.3% preferred the lingualized occlusion. However, when the two groups' satisfaction scores were modeled using the three main key indicator questions (general satisfaction, general ability to chew, or general function), there were no significant differences between them. Conclusions: Within the limitations of a small number of participants, the majority of them still indicated a preference for a physiologic occlusion for implant overdentures. Improved function was given as the main indicator for that preference. Having implant overdentures in one or both jaws is not a formative factor in patient's opinions on occlusal schemes. [source]
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