Settlement and society in the Welsh Marches during the first millennium BC.

SIGLEAvailable from British Library Document Supply Centre-DSC:DXN041726 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Nutritional Ecology: A First Vegetarian Spider

SummaryMutualisms are ubiquitous in nature and equally commonplace is their exploitation. A well-known mutualism has been found to be exploited from a surprising source: the first described vegetarian spider dines on trophic structures produced by acacia trees to reward their mutualistic protective ants

An application of the theory of planned behavior to student retention

Although student integration theory, a sociologically-based model, has been the dominant explanation for student drop-out from colleges for over 40 years, it has received only mixed empirical support in residential colleges and less in non-residential colleges. Psychological theories of active choice and behavior change offer an alternative explanation for drop-out. In research at a non-residential UK university, structural equation modeling was used in two separate studies to compare a model of student dropout based on student integration theory with a psychological model based on the theory of planned behavior (TPB). In the first study (N=633), a model including TPB variables and two key student integration theory variables (academic integration, and social integration) showed good fit to the data, Although all three TPB variables predicted intention to quit, neither of the two student integration theory variables did so. The TPB variables explained over 60% of the variance in student's intention to voluntarily withdraw from college before completing their studies, and intention to withdraw was associated with actual dropout behavior. In the second study (N=180), using alternative measures of student integration theory factors, a model including both student integration theory and TPB variables had acceptable fit, and over 70% of the variance in intention to quit was explained. But only the TPB variables predicted intention to quit significantly. The benefits of adopting a process-based psychological explanation to student retention are discussed

When effects are confounded, they cannot be interpreted: A study of confounding in assessment centre ratings

Background. Dimensions (e.g., communication skills, health awareness) measured through multifaceted measures hold a key position across a vast array of disciplines relevant to health and organisations. However, the measurement properties of dimensions have long been affected by confounds. The outcome of confounding in the context of multifaceted measurement is that the extent to which reliable variance in ratings reflects dimensions is difficult or impossible to establish. Nowhere have dimensions been scrutinized more closely than in the literature on assessment centres (ACs). In recent years, dimensions have enjoyed a revival in the AC literature and now feature as important, meaningful, and impactful variables of interest in a range of different studies published in leading journals (e.g., Journal of Applied Psychology, Personnel Psychology). However, none of these studies have fully accounted for confounding. As a consequence, the extent to which the effects found in these studies are attributable to dimensions, or to a multitude of other variables relevant to ACs, is unclear. This issue has implications for any context in which the aim is to measure dimensions using multiple samples of behaviour. Study Aim. Our aim is to disentangle the different effects in AC ratings in order to establish what role dimensions have in AC ratings as distinct from other effects in AC ratings (i.e., different samples, rating items, assessors, and exercises). Doing so would work towards informing the discipline about the "real" basis for AC ratings and, more widely, about the role of dimensions in multifaceted measures. Method. Ratings were collected from an operational AC used in a public institution. The AC under study was developed according to international guidelines. Data were subjected to a Bayesian random effects analysis. Results. Results suggested that when confounding is (properly) taken into account, AC ratings have little to do with dimensions. The lion's share of variance in AC ratings is accounted for by (a) a general performance factor and (b) exercise-related effects. Discussion. The findings of the current study call into question the interpretation of much of the "dimension revival" literature on ACs and the role of dimensions in organization-related studies. They suggest that if dimensions are the intended focus for assessment in ACs, an AC does not allow sufficient high fidelity behavioural sampling for such variables to manifest. In the light of these findings, we call for an alternative direction for AC research and practice

Evaluation of forensic DNA traces when propositions of interest relate to activities: analysis and discussion of recurrent concerns

When forensic scientists evaluate and report on the probative strength of single DNA traces, they commonly rely on only one number, expressing the rarity of the DNA profile in the population of interest. This is so because the focus is on propositions regarding the source of the recovered trace material, such as “the person of interest is the source of the crime stain.” In particular, when the alternative proposition is “an unknown person is the source of the crime stain,” one is directed to think about the rarity of the profile. However, in the era of DNA profiling technology capable of producing results from small quantities of trace material (i.e., non-visible staining) that is subject to easy and ubiquitous modes of transfer, the issue of source is becoming less central, to the point that it is often not contested. There is now a shift from the question “whose DNA is this?” to the question “how did it get there?” As a consequence, recipients of expert information are now very much in need of assistance with the evaluation of the meaning and probative strength of DNA profiling results when the competing propositions of interest refer to different activities. This need is widely demonstrated in day-to-day forensic practice and is also voiced in specialized literature. Yet many forensic scientists remain reluctant to assess their results given propositions that relate to different activities. Some scientists consider evaluations beyond the issue of source as being overly speculative, because of the lack of relevant data and knowledge regarding phenomena and mechanisms of transfer, persistence and background of DNA. Similarly, encouragements to deal with these activity issues, expressed in a recently released European guideline on evaluative reporting (Willis et al., 2015), which highlights the need for rethinking current practice, are sometimes viewed skeptically or are not considered feasible. In this discussion paper, we select and discuss recurrent skeptical views brought to our attention, as well as some of the alternative solutions that have been suggested. We will argue that the way forward is to address now, rather than later, the challenges associated with the evaluation of DNA results (from small quantities of trace material) in light of different activities to prevent them being misrepresented in court

Everything that you have ever been told about assessment center ratings is confounded

Despite a substantial research literature on the influence of dimensions and exercises in assessment centers (ACs), the relative impact of these two sources of variance continues to raise uncertainties because of confounding. With confounded effects, it is not possible to establish the degree to which any one effect, including those related to exercises and dimensions, influences AC ratings. In the current study (N = 698) we used Bayesian generalizability theory to unconfound all of the possible effects contributing to variance in AC ratings. Our results show that ≤ 1.11% of the variance in AC ratings was directly attributable to behavioral dimensions, suggesting that dimension-related effects have no practical impact on the reliability of ACs. Even when taking aggregation level into consideration, effects related to general performance and exercises accounted for almost all of the reliable variance in AC ratings. The implications of these findings for recent dimension- and exercise-based perspectives on ACs are discussed

Comparison of Different Minimal Velocity Thresholds to Establish Deadlift One Repetition Maximum

The aim of this study was to compare the actual deadlift one repetition maximum (1RM) and the deadlift 1RM predicted from individualised load-velocity profiles. Twelve moderately resistance-trained men participated in three deadlift sessions. During the first, 1RM was assessed; during the second, load-velocity profiles were recorded with six loads (65% to 90% 1RM) using a linear position transducer recording at 1000 Hz; and during the third, minimal velocity thresholds (MVT) were recorded from the velocity of the last repetition during sets to volitional fatigue with 70% and 80% 1RM with a linear position transducer recording at 1000 Hz. Regression was then used to generate individualised load-velocity profiles and the MVT was used as a cut-off value from which to predict deadlift 1RM. In general, velocity reliability was poor to moderate. More importantly, predicted deadlift 1RMs were significantly and meaningfully less than actual deadlift 1RMs (p < 0.05, d = 1.03–1.75). The main practical application that should be taken from the results of this study is that individualized load-velocity profiles should not be used to predict deadlift 1RM. Practitioners should not use this method in combination with the application of MVT obtained from the last repetition of sets to volitional fatigue

Multi-mycotoxin exposure assessment in UK children using urinary biomarkers - a pilot survey

Peer reviewedPostprin

Evaluation of Forensic DNA Traces When Propositions of Interest Relate to Activities : Analysis and Discussion of Recurrent Concerns

When forensic scientists evaluate and report on the probative strength of single DNA traces, they commonly rely on only one number, expressing the rarity of the DNA profile in the population of interest. This is so because the focus is on propositions regarding the source of the recovered trace material, such as “the person of interest is the source of the crime stain.” In particular, when the alternative proposition is “an unknown person is the source of the crime stain,” one is directed to think about the rarity of the profile. However, in the era of DNA profiling technology capable of producing results from small quantities of trace material (i.e., non-visible staining) that is subject to easy and ubiquitous modes of transfer, the issue of source is becoming less central, to the point that it is often not contested. There is now a shift from the question “whose DNA is this?” to the question “how did it get there?” As a consequence, recipients of expert information are now very much in need of assistance with the evaluation of the meaning and probative strength of DNA profiling results when the competing propositions of interest refer to different activities. This need is widely demonstrated in day-to-day forensic practice and is also voiced in specialized literature. Yet many forensic scientists remain reluctant to assess their results given propositions that relate to different activities. Some scientists consider evaluations beyond the issue of source as being overly speculative, because of the lack of relevant data and knowledge regarding phenomena and mechanisms of transfer, persistence and background of DNA. Similarly, encouragements to deal with these activity issues, expressed in a recently released European guideline on evaluative reporting (Willis et al., 2015), which highlights the need for rethinking current practice, are sometimes viewed skeptically or are not considered feasible. In this discussion paper, we select and discuss recurrent skeptical views brought to our attention, as well as some of the alternative solutions that have been suggested. We will argue that the way forward is to address now, rather than later, the challenges associated with the evaluation of DNA results (from small quantities of trace material) in light of different activities to prevent them being misrepresented in court