Towards microbiological quality assurance in radiation sterilization processing: a limiting case model

A Limiting Case Model has been developed which describes the dependence on radiation dose of the proportion of items, in a population of items subjected to irradiation, which are contaminated by one or more organisms. This model is independent of the initial distribution of numbers of micro-organisms on items and represents a conservative approach to estimation of the proportions of non-sterile items in an irradiated population of items.     

Towards microbiological quality assurance in radiation sterilization processing: the limiting case model applied to a microbial population having a distribution of radiation responses

A limiting case model, developed earlier to provide a conservative estimate of the proportion of non-sterile items ( P ) in an irradiated population of items contaminated with micro-organisms of a single type, has been extended to include items having organisms of different types. Estimates of P are compared with exact values derived on purely theoretical grounds and with values obtained by computer simulation of microbiological inactivation on items.     

Ordinal-To-Interval Scale Conversion Tables and National Items for the New Zealand Version of the WHOQOL-BREF

The World Health Organisation Quality of Life (WHOQOL) questionnaires are widely used around the world and can claim strong cross-cultural validity due to their development in collaboration with international field centres. To enhance conceptual equivalence of quality of life across cultures, optional national items are often developed for use alongside the core instrument. The present study outlines the development of national items for the New Zealand WHOQOL-BREF. Focus groups with members of the community as well as health experts discussed what constitutes quality of life in their opinion. Based on themes extracted of aspects not contained in the existing WHOQOL instrument, 46 candidate items were generated and subsequently rated for their importance by a random sample of 585 individuals from the general population. Applying importance criteria reduced these items to 24, which were then sent to another large random sample (n = 808) to be rated alongside the existing WHOQOL-BREF. A final set of five items met the criteria for national items. Confirmatory factor analysis identified four national items as belonging to the psychological domain of quality of life, and one item to the social domain. Rasch analysis validated these results and generated ordinal-to-interval conversion algorithms to allow use of parametric statistics for domain scores with and without national items.     

口唇部活体测量及生长发育研究

报告４３０８例幼儿至青少年期口唇部１１项指标活体测量的均数及性别差异。发现少年以前口部无显著性的性差,唇高等８项指标自１３岁开始,红唇高等３项开始,红唇高等３项指标在１８岁后开始出现明显性差。唇高等６项指标生长发育曲线随年龄增长上升平缓,无生长发育高峰。口裂宽等５项指标的曲线则随年龄增长上升较陡,有明显的发育高峰。     

Visual categorization of natural and abstract items in forest monkeys and humans

A preference for novelty paradigm was used to investigate whether mangabeys (Lophocebus albigena), an arboreal non-human primate species, were able to discriminate and to categorize different visual stimuli belonging to natural (food items) and abstract (non-food items) categories. In a comparative perspective human subjects were tested with the same procedure and the same stimuli. Two out of four mangabeys and three out of the four humans showed significant preference for novelty when comparing food versus non-food items. Hence they discriminated between these two sets of items. The two mangabeys and one non-adult human subject sorted the food items in one category, showing no preference for novelty when comparing known and unknown food-items and different views of the same food items. In contrast the two adult human subjects who showed preference for novelty in the between-category, did not show preference for novelty when comparing known and unknown food-items but did show such a preference when comparing different views of the same food items. Compared to human performances, the results suggest that mangabeys are able to form at least a perceptual category of natural, ecologically relevant stimuli.     

Optimal foraging by the swallow (Hirundo rustica, L): Prey size selection

The foraging ecology of the swallow (Hirundo rustica) was investigated in the field and compared with predictions of optimal foraging theory. Prey items were selected primarily by size. The inclusion of an item in the diet depended on the absolute abundance of the high-ranking prey and not of the low-ranking ones. Small items of low profitability were, however, included when food was abundant and more small items were taken when they were relatively abundant. Energetics data are used to show that it is profitable in terms of net energy gain for the swallow to take a mixture of large and small items, whereas optimal foraging theory would predict exclusive specialization on large, high-ranking items. Other possible explanations for the inclusion of small items in the diet are discussed.     

Priming picture naming with a semantic task: an fMRI investigation

Prior semantic processing can enhance subsequent picture naming performance, yet the neurocognitive mechanisms underlying this effect and its longevity are unknown. This functional magnetic resonance imaging study examined whether different neurological mechanisms underlie short-term (within minutes) and long-term (within days) facilitation effects from a semantic task in healthy older adults. Both short- and long-term facilitated items were named significantly faster than unfacilitated items, with short-term items significantly faster than long-term items. Region of interest results identified decreased activity for long-term facilitated items compared to unfacilitated and short-term facilitated items in the mid-portion of the middle temporal gyrus, indicating lexical-semantic priming. Additionally, in the whole brain results, increased activity for short-term facilitated items was identified in regions previously linked to episodic memory and object recognition, including the right lingual gyrus (extending to the precuneus region) and the left inferior occipital gyrus (extending to the left fusiform region). These findings suggest that distinct neurocognitive mechanisms underlie short- and long-term facilitation of picture naming by a semantic task, with long-term effects driven by lexical-semantic priming and short-term effects by episodic memory and visual object recognition mechanisms.     

Food of White Catfish,Ictalurus catus (LINN.) (Ictaluridae) Stocked in Farm Ponds

Stomach contents of 124 white catfish, Ictalurus catus, ranging from 51 to 431 mm collected from farm ponds of Auburn University, Auburn, Alabama were examined. Fishes in these ponds were given supplemental feed six days a week. Juvenile catfish below 100 mm fed more actively on a variety of food items than larger fish. White catfish measuring 201 mm and above preferred dipterans to other natural food items. In all size groups supplemental feed occupied a dominant position when compared to other food items. Other food items present in the stomachs in varying quantities included detritus, micro-crustaceans, trichopterans, fish remains and miscellaneous items, thus indicating the omnivorous feeding of white catfish.     

Seasonal changes in food resource distribution and feeding sites selected by Japanese macaques on Koshima Islet,Japan

Feeding sites of Japanese macaques (Macaca fuscata) change according to seasonal fluctuations in food resource distribution. To examine what characteristics of food items affect feeding site selection, I describe herein the seasonal changes in food items, feeding sites, and food resource distributions of this species. Feeding behavior of monkeys and their food resource distributions were investigated on Koshima Islet, southern Japan, for four study periods (i.e., seasons) in 2002. Monkeys showed large variations in their diet between seasons. To weigh the relative influence of the distribution and abundance of food items on feeding site selection in each season, multiple regression analyses were performed by 100 m × 100 m grid. In the analyses, feeding time was a dependent variable and the abundance of staple food items, for which feeding time was over 5% in each season, in each grid square was an independent variable. There was no correlation between the resource distribution of most food items and the distribution of feeding time by monkeys in each season. Monkeys spent more feeding time where multiple staple food items were available. Food items that affected feeding site selection by monkeys had the following three characteristics: (1) clumped distribution, (2) seasonal availability, and (3) fruit. This suggests that monkeys are likely to select feeding sites to consume food items whose availability is limited temporally and spatially, which may enable them to simultaneously use other widely distributed, abundant food items efficiently.     

Construction of a scale to signal personality disorders in the elderly

Till now, no specific diagnostic instruments to detect personality disorders in the elderly are available. The aim of our study was to contribute to the construction of a reliable en valid instrument for the detection of personality disorders in older adults. Therefore, a draft version of the instrument was constructed both for the patient and the informant. Both the patient and the informant version of the instrument included 52 items with the same content. These items concerned Habitual behaviour (HAB), Biographical information (BIO) and Observation of actual behaviour (OBS). 159 clients of 60 years and older of a Dutch ambulatory mental health care organisation were assessed with the screening instrument. In 96 of the 159 outpatients one or more informants were included. The results indicate that the internal consistency of seven HAB items, nine BIO items and five OBS items was moderate to good with regard to both the patient and informant instrument. Test-retest reliability of the 21 items of the patient instrument was moderate with regard to HAB, excellent with regard to BIO and moderate with regard to OBS. Interrater reliability of OBS was also moderate. The criterion validity (criterion: DSM-IV TR Axis II classification) of HAB, BIO and OBS based on the 21 items of the patient instrument was fair and with regard to the same 21 items of the informant instrument insufficient. In conclusion, sixteen out of 52 potential items of the patient's draft version of the screening instrument can be used to detect a possible personality disorder. These sixteen items from the HAB and BIO scale are named the Gerontological Personality disorder Scale (GPS). Medical doctors, psychologists and nurses working in ambulatory mental health organisation can use the GPS as a resource during the diagnostic process. Whether the GPS can be used beyond mental health organisations, for example by general practitioners is a subject for future studies.     

Zygosity diagnosis in young twins by questionnaire for twins' mothers and twins' self-reports.

The present study deals with the determination of zygosity in twins of childhood age by simple questionnaire. The subjects were 224 twin pairs and their mothers, consisting of 159 monozygotic and 65 same-sex dizygotic pairs, identified by genetic markers including DNA samples. Mothers of twins responded to 19 questionnaire items dealing with twin similarity in 16 items about physical features and 3 items about the degree of similarity and frequency of being mistaken (confusion of identity) when twins were about 1 year of age. The twins themselves responded to three questionnaire items dealing with only confusion of identity items. The results of stepwise logistic regression analysis were as follows: the total accuracy of the mothers' questionnaire was 91.5% when using only the items dealing with confusion of identity. This accuracy was slightly lower than that obtained by twins' self-reports dealing with nearly the same question items of confusion of identity, answered by both twins separately with 93.3% accuracy. The total accuracy of mothers' questionnaire responses rose to 95.1% when we used all 19 items. In addition to "the frequency of being mistaken", two physical features, namely "shape of fingers" and "shape of eyebrow", were very informative. In conclusion, twin zygosity can be estimated by the use of the mothers' simple questionnaire with sufficient accuracy even in very young twins about 1 year of age.     

Ineffectiveness of Reverse Wording of Questionnaire Items: Let’s Learn from Cows in the Rain

Objective

We examined the effectiveness of reverse worded items as a means of reducing or preventing response bias. We first distinguished between several types of response bias that are often confused in literature. We next developed arguments why reversing items is probably never a good way to address response bias. We proposed testing whether reverse wording affects response bias with item-level data from the Multidimensional Fatigue Inventory (MFI-20), an instrument that contains reversed worded items.

Methods

With data from 700 respondents, we compared scores on items that were similar with respect either to content or to direction of wording. Psychometric properties of sets of these items worded in the same direction were compared with sets consisting of both straightforward and reversed worded items.

Results

We did not find evidence that ten reverse-worded items prevented response bias. Instead, the data suggest scores were contaminated by respondent inattention and confusion.

Conclusions

Using twenty items, balanced for scoring direction, to assess fatigue did not prevent respondents from inattentive or acquiescent answering. Rather, fewer mistakes are made with a 10-item instrument with items posed in the same direction. Such a format is preferable for both epidemiological and clinical studies.     

Development and assessment of floor and ceiling items for the PROMIS physical function item bank

Introduction

Disability and Physical Function (PF) outcome assessment has had limited ability to measure functional status at the floor (very poor functional abilities) or the ceiling (very high functional abilities). We sought to identify, develop and evaluate new floor and ceiling items to enable broader and more precise assessment of PF outcomes for the NIH Patient-Reported-Outcomes Measurement Information System (PROMIS).

Methods

We conducted two cross-sectional studies using NIH PROMIS item improvement protocols with expert review, participant survey and focus group methods. In Study 1, respondents with low PF abilities evaluated new floor items, and those with high PF abilities evaluated new ceiling items for clarity, importance and relevance. In Study 2, we compared difficulty ratings of new floor items by low functioning respondents and ceiling items by high functioning respondents to reference PROMIS PF-10 items. We used frequencies, percentages, means and standard deviations to analyze the data.

Results

In Study 1, low (n = 84) and high (n = 90) functioning respondents were mostly White, women, 70 years old, with some college, and disability scores of 0.62 and 0.30. More than 90% of the 31 new floor and 31 new ceiling items were rated as clear, important and relevant, leaving 26 ceiling and 30 floor items for Study 2. Low (n = 246) and high (n = 637) functioning Study 2 respondents were mostly White, women, 70 years old, with some college, and Health Assessment Questionnaire (HAQ) scores of 1.62 and 0.003. Compared to difficulty ratings of reference items, ceiling items were rated to be 10% more to greater than 40% more difficult to do, and floor items were rated to be about 12% to nearly 90% less difficult to do.

Conclusions

These new floor and ceiling items considerably extend the measurable range of physical function at either extreme. They will help improve instrument performance in populations with broad functional ranges and those concentrated at one or the other extreme ends of functioning. Optimal use of these new items will be assisted by computerized adaptive testing (CAT), reducing questionnaire burden and insuring item administration to appropriate individuals.     

The ZZP Questionnaire. Reliability of a new resource utilization measure

Data to determine the resource utilization of care recipients need to be reliable and the items that are measured need to be useful. In 2006, the Dutch Ministry of Health and Welfare has mandated all nursing homes and homes for the elderly to measure the Resource Utilization of all residents with the ZZP Questionnaire. Are the data resulting from this measurement reliable and is each of the 54 items of the ZZP Questionnaire useful? To answer this we tested the reliability of the data in a nursing home and a home for the elderly in two wards each. For 122 residents questionnaires were completed such that the inter- and intra-rater reliability of the answers could be assessed. Ten of the 54 items in the questionnaire showed insufficient inter rater reliability (<0.40) on the weighted Cohen kappa and another sixteen moderate (0.40 - 0.60). On the intra rater reliability test seven items had an insufficient kappa and another fifteen moderate. Besides, ten clusters of items could be formed with in-cluster Spearman correlation rates of .75 or higher. From the results of the reliability tests and the item intercorrelation rates we concluded that a substantial number of items needs to be improved and that in the ZZP Questionnaire 15 of the 54 items appear to be redundant on statistical grounds.     

Observations of floating anthropogenic litter in the Barents Sea and Fram Strait,Arctic

Although recent reports indicate that anthropogenic waste has made it to the remotest parts of our oceans, there is still only limited information about its spread, especially in polar seas. Here, we present litter densities recorded during ship- and helicopter-based observer surveys in the Barents Sea and Fram Strait (Arctic). Thirty-one items were recorded in total, 23 from helicopter and eight from research vessel transects. Litter quantities ranged between 0 and 0.216 items km^?1 with a mean of 0.001 (±SEM 0.005) items km^?1. All of the floating objects observed were plastic items. Litter densities were slightly higher in the Fram Strait (0.006 items km^?1) compared with the Barents Sea (0.004 items km^?1). More litter was recorded during helicopter-based surveys than during ship-based surveys (0.006 and 0.004 items km^?1, respectively). When comparing with the few available data with the same unit (items km^?1 transect), the densities found herein are slightly higher than those from Antarctica but substantially lower than those from temperate waters. However, since anthropogenic activities in the Fram Strait are expanding because of sea ice shrinkage, and since currents from the North Atlantic carry a continuous supply of litter to the north, this problem is likely to worsen in years to come unless serious mitigating actions are taken to reduce the amounts of litter entering the oceans.     

Summation and quantity judgments of sequentially presented sets by capuchin monkeys (Cebus apella)

Capuchin monkeys (Cebus apella) were presented with two sets of food items, identical in food type but differing in number. Animals selected one set and were permitted to consume their choice. Set sizes ranged from 1 to 6 items. In experiment 1, each set was uncovered and recovered before a response was made, and the monkeys selected the larger set at high levels. Experiment 2 presented sets that had both visible and nonvisible food items in them at the time of the response, thus requiring the monkeys to sum the total amount of food that was available. The monkeys again selected the larger set with no decrement in performance. Overall, the data indicate that capuchins, like other more extensively studied primate species in this area of research, are responsive to quantitative differences between sets. Capuchins succeed in making these quantity judgments when sets are nonvisible at choice time and when summation of items must be performed, thus demonstrating coordination of quantification skills and memory. Capuchins also inhibit responses to visible food items when those items are only part of an overall smaller quantity of food compared with a completely nonvisible set.     

Risky Business: Factor Analysis of Survey Data – Assessing the Probability of Incorrect Dimensionalisation

This paper undertakes a systematic assessment of the extent to which factor analysis the correct number of latent dimensions (factors) when applied to ordered-categorical survey items (so-called Likert items). We simulate 2400 data sets of uni-dimensional Likert items that vary systematically over a range of conditions such as the underlying population distribution, the number of items, the level of random error, and characteristics of items and item-sets. Each of these datasets is factor analysed in a variety of ways that are frequently used in the extant literature, or that are recommended in current methodological texts. These include exploratory factor retention heuristics such as Kaiser’s criterion, Parallel Analysis and a non-graphical scree test, and (for exploratory and confirmatory analyses) evaluations of model fit. These analyses are conducted on the basis of Pearson and polychoric correlations. We find that, irrespective of the particular mode of analysis, factor analysis applied to ordered-categorical survey data very often leads to over-dimensionalisation. The magnitude of this risk depends on the specific way in which factor analysis is conducted, the number of items, the properties of the set of items, and the underlying population distribution. The paper concludes with a discussion of the consequences of over-dimensionalisation, and a brief mention of alternative modes of analysis that are much less prone to such problems.     

Maintenance of delay of gratification by four chimpanzees (Pan troglodytes): the effects of delayed reward visibility, experimenter presence, and extended delay intervals

Previous research in our laboratory has demonstrated that chimpanzees can delay gratification by inhibiting consumption of available food items for as long as 3 min as an experimenter transfers additional food items from a transparent container to a bowl placed in front of the subject. In this study, we examined the influence of the visibility of the food source, as well as the presence of the experimenter, on four chimpanzees' self-control in this paradigm. In Experiment 1 an experimenter transferred 15 preferred food items between a distant opaque container and a bowl placed in front of the subject. In Experiment 2 we tested the chimpanzees with an automated system that (in the absence of the experimenter) transferred up to 36 highly preferred food items from a universal food dispenser to a container located either inside or outside of the subject's enclosure. There were no differences in self-directed behaviors or attentiveness to the food items between the self-imposed and externally imposed delay conditions. A final experiment with the automated paradigm indicated that individuals could delay gratification for up to 11min in order to obtain all 36 food items.     

Lacking Control over the Trade-Off between Quality and Quantity in Visual Short-Term Memory

Visual short-term memory (VSTM) is limited in the quantity and quality of items that can be retained over time. Importantly, these two mnemonic parameters interact: increasing the number of items in VSTM reduces the quality with which they are represented. Here, we ask whether this trade-off is under top-down control. Specifically, we test whether participants can strategically optimise the trade-off between quality and quantity for VSTM according to task demands. We manipulated strategic trade-off by varying expectations about the number of to-be-remembered items (Experiments 1-2) or the precision required for the memory-based judgement (Experiment 3). In a final experiment, we manipulated both variables in a complementary way to maximise the motivation to strategically control the balance between number and the quality of items encoded into VSTM. In different blocks, performance would benefit most either by encoding a large number of items with low precision or by encoding a small number of items with high precision (Experiment 4). In all experiments, we compared VSTM performance on trials matched for mnemonic demand, but within contexts emphasising the quality or quantity of VSTM representations. Across all four experiments, we found no evidence to suggest that participants use this contextual information to bias the balance between the number and precision of items in VSTM. Rather, our data suggest that the trade-off may be determined primarily by stimulus-driven factors at encoding.