419 research outputs found
Characteristics of Conservation Laws for Difference Equations
Each conservation law of a given partial differential equation is determined (up to equivalence) by a function known as the characteristic. This function is used to find conservation laws, to prove equivalence between conservation laws, and to prove the converse of Noether's Theorem. Transferring these results to difference equations is nontrivial, largely because difference operators are not derivations and do not obey the chain rule for derivatives. We show how these problems may be resolved and illustrate various uses of the characteristic. In particular, we establish the converse of Noether's Theorem for difference equations, we show (without taking a continuum limit) that the conservation laws in the infinite family generated by Rasin and Schiff are distinct, and we obtain all five-point conservation laws for the potential Lotka-Volterra equation
Whole body active warm up and inspiratory muscle warm up do not improve running performance when carrying thoracic loads
Whole body active warm ups (AWU) and inspiratory muscle warm up (IMW) prior to exercise improves performance on some endurance exercise tasks. This study investigated the effects of AWU with and without IMW upon 2.4 km running time-trial performance while carrying a 25 kg backpack, a common task and backpack load in physically demanding occupations. Participants (n = 9) performed five 2.4 km running time-trials with a 25 kg thoracic load preceded in random order by 1) IMW comprising 2 x 30 inspiratory efforts against a pressure-threshold load of 40 % maximal inspiratory pressure (PImax), 2) 10 min unloaded running (AWU) at lactate turnpoint (10.33 ± 1.58 km·h-1), 3) placebo IMW (PLA) comprising five min breathing using a sham device, 4) AWU+IMW and 5) AWU+PLA. Pooled baseline PImax was similar between trials and increased by 7% and 6% following IMW and AWU+IMW (P0.05). Time-trial performance was not different between any trials. Whole body AWU and IMW performed alone or combination have no ergogenic effect upon high intensity, short duration performance when carrying a 25 kg load in a backpack.N/
Behavioural inhibition and behavioural activation system scales for children: Relationships with Eysenck's personality traits and psychopathological symptoms
This study examined the psychometric properties of an age-downward version of the Carver and White (1994) BIS/BAS scales. Normal school children (N = 284) aged 8-12 years completed the BIS/BAS scales as well as scales of Neuroticism, Extraversion, and psychopathological symptoms. Results showed that the BIS/BAS scales for children had a theoretically meaningful factor structure and satisfactory reliability. Relationships with Eysenck's personality traits of Neuroticism and Extraversion, and psychopathological symptoms were generally as expected. That is, Neuroticism was positively associated with both BIS and BAS, whereas Extraversion was negatively related to BIS but positively to BAS. Further, BIS was convincingly connected to higher levels of internalizing symptoms, whereas BAS was to a certain level related to externalizing symptoms
Psychotherapy mediated by remote communication technologies: a meta-analytic review
Reproduced with permission of the publisher. © 2008 Bee et al; licensee BioMed Central Ltd. The electronic version of this article is the complete one and can be found online at: http://www.biomedcentral.com/1471-244X/8/60. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Background
Access to psychotherapy is limited by psychopathology (e.g. agoraphobia), physical disability, occupational or social constraints and/or residency in under-served areas. For these populations, interventions delivered via remote communication technologies (e.g. telephone, internet) may be more appropriate. However, there are concerns that such delivery may influence the therapeutic relationship and thus reduce therapy effectiveness. This review aimed to determine the clinical effectiveness of remotely communicated, therapist-delivered psychotherapy.
Methods
Systematic review (including electronic database searching and correspondence with authors) of randomised trials of individual remote psychotherapy. Electronic databases searched included MEDLINE (1966–2006), PsycInfo (1967–2006), EMBASE (1980–2006) and CINAHL databases (1982–2006). The Cochrane Central Register of Controlled Trials (CENTRAL) and the Cochrane Collaboration Depression, Anxiety and Neurosis Controlled Trials Register (CCDAN-CTR). All searches were conducted to include studies with a publication date to July 2006.
Results
Thirteen studies were identified, ten assessing psychotherapy by telephone, two by internet and one by videoconference. Pooled effect sizes for remote therapy versus control conditions were 0.44 for depression (95%CI 0.29 to 0.59, 7 comparisons, n = 726) and 1.15 for anxiety-related disorders (95%CI 0.81 to 1.49, 3 comparisons, n = 168). There were few comparisons of remote versus face-to-face psychotherapy.
Conclusion
Remote therapy has the potential to overcome some of the barriers to conventional psychological therapy services. Telephone-based interventions are a particularly popular research focus and as a means of therapeutic communication may confer specific advantages in terms of their widespread availability and ease of operation. However, the available evidence is limited in quantity and quality. More rigorous trials are required to confirm these preliminary estimates of effectiveness. Future research priorities should include overcoming the methodological shortcomings of published work by conducting large-scale trials that incorporate both clinical outcome and more process-orientated measures
‘Mind the Gap’ between ecosystem services classification and strategic decision making
Ecosystem services (ES) are increasingly embedded in policy agendas, but if and how policy actors are considering them is not often reported. This study assesses the extent to which ES were considered by key policy actors involved in the strategic decision-making process leading to an innovative large-scale Dutch coastal management project. We analysed retrospective interviews to ascertain which ES were considered and how they were described by policy actors. Over half of the quotes (118/228) and 16 out of the 17 interviewees referred to three broad ES categories, with high degrees of adoption: coastal safety, recreation and cognitive development (learning by doing). The broad terms ‘nature’ and ‘spatial quality’ were also referenced often (36 times). Our findings suggest that broad, unspecified ecosystem services were adopted highly by the policy actors, while specific ecosystem service categories were rarely considered. Relatable and comprehensible cultural ecosystem services also constituted critical arguments for policy actors in their strategic decision making. We reflect that ambiguous, broad terms can help to garner support and unite efforts across disciplinary and institutional boundaries. For ES to align with relevant aspects of decision making, a ‘translation step’ between ES research and decision making might be required and ambiguity should be acknowledged.</p
Cross-cultural adaptation of the condition-specific malocclusion impact questionnaire for the Malayalam-speaking population—a psychometric scale validation study
Objectives
The study aimed to develop a regional version of the Malocclusion Impact Questionnaire (MIQ-Malayalam) for the Malayalam-speaking Indian population.
Methods
The English version of MIQ was translated into Malayalam through a rigorous translation process, followed by cross-cultural adaptation. Young people aged below 18 years who were just about to start orthodontic treatment were invited to complete the Malayalam version of MIQ along with the available native version of the Psychosocial Impact of Dental Aesthetics Questionnaire (PIDAQ). The MIQ-Malayalam was readministered after 14 days to assess test-retest reliability. Treatment need was assessed normatively using the Dental Health Component of the Index of Orthodontic Treatment Need (IOTN-DHC) and subjectively using Aesthetic Component of the Index of Orthodontic Treatment Need (IOTN-AC).
Results
A total of 210 subjects completed the questionnaires (males = 47.2%; females = 52.8%; age = 12-17 years, mean = 15 years and 3 months; standard deviation = 1.9) and 50 completed repeat questionnaires. Internal consistency and test-retest reliability were high (Cronbach’s alpha = 0.952; Intra-class Correlation Coefficient = 0.93). Exploratory factor analysis derived 4 factors with exclusion of 1 item. There were significant differences (P < .05) in MIQ scores between IOTN-DHC subgroups, ensuring discriminant validity. There was a high correlation between total MIQ and total PIDAQ scores (rho = 0.884), while low between total MIQ and IOTN-AC scores (rho = 0.203).
Conclusion
The Malayalam version of MIQ was found to be valid and reliable and can serve as a useful condition-specific measure of oral health-related quality of life
Bonding in MgSi and AlMgSi Compounds Relevant to AlMgSi Alloys
The bonding and stability of MgSi and AlMgSi compounds relevant to AlMgSi
alloys is investigated with the use of (L)APW+(lo) DFT calculations. We show
that the and phases found in the precipitation sequence are
characterised by the presence of covalent bonds between Si-Si nearest neighbour
pairs and covalent/ionic bonds between Mg-Si nearest neighbour pairs. We then
investigate the stability of two recently discovered precipitate phases, U1 and
U2, both containing Al in addition to Mg and Si. We show that both phases are
characterised by tightly bound Al-Si networks, made possible by a transfer of
charge from the Mg atoms.Comment: 11 pages, 30 figures, submitted to Phys. Rev.
Prognostic impact of low muscle mass and low muscle density in patients with diffuse large B-cell lymphoma
Low muscle mass (LMM) and low muscle density (LMD) are increasingly recognized as prognostic factors for survival in different malignancies. This study determined the association of LMM and LMD with survival in DLBCL (diffuse large B-cell lymphoma) patients. CT-based measurement of muscle was performed in 164 DLBCL patients prior to chemo-immunotherapy. Z-scores adjusted for gender, age, and body mass index were derived from a healthy reference population. LMM or LMD were defined as a Z-score below −1 and were related to OS and PFS. The co-existence of both LMM and LMD was observed in 13% of the DLBCL patients and was significantly associated with shorter OS and PFS. Also, these patients more often did not complete the planned treatment. The combination of LMM and LMD is an independent prognosti
Comparisons of Supergranule Characteristics During the Solar Minima of Cycles 22/23 and 23/24
Supergranulation is a component of solar convection that manifests itself on
the photosphere as a cellular network of around 35 Mm across, with a turnover
lifetime of 1-2 days. It is strongly linked to the structure of the magnetic
field. The horizontal, divergent flows within supergranule cells carry local
field lines to the cell boundaries, while the rotational properties of
supergranule upflows may contribute to the restoration of the poloidal field as
part of the dynamo mechanism that controls the solar cycle. The solar minimum
at the transition from cycle 23 to 24 was notable for its low level of activity
and its extended length. It is of interest to study whether the convective
phenomena that influences the solar magnetic field during this time differed in
character to periods of previous minima. This study investigates three
characteristics (velocity components, sizes and lifetimes) of solar
supergranulation. Comparisons of these characteristics are made between the
minima of cycles 22/23 and 23/24 using MDI Doppler data from 1996 and 2008,
respectively. It is found that whereas the lifetimes are equal during both
epochs (around 18 h), the sizes are larger in 1996 (35.9 +/- 0.3 Mm) than in
2008 (35.0 +/- 0.3 Mm), while the dominant horizontal velocity flows are weaker
(139 +/- 1 m/s in 1996; 141 +/- 1 m/s in 2008). Although numerical differences
are seen, they are not conclusive proof of the most recent minimum being
inherently unusual.Comment: 22 pages, 5 figures. Solar Physics, in pres
- …