3,958 research outputs found

    Two-Dimensional Cutting Problem

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    This paper deals with two-dimensional cutting problems. Firstly the complexity of the problem in question is estimated. Then, several known approaches for the regular (rectangular) and irregular (not necessarily rectangular) cutting problems are described. In the second part, a decision support system for cutting a rectangular sheet of material into pieces of arbitrary shapes, is presented. The system uses two earlier described methods which prefer different types of data and the user may decide which one is more suitable for the problem in question. After brief description of system data files and its manual, some experimental results are presented

    H-index in medicine is driven by original research

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    Aim To investigate the contribution of selected types of articles to h-indices of medical researchers. Methods We used the Web of Science to export the publication records of various members from 26 scientific medical societies (13 European, 13 North American) associated with 13 medical specialties. Those included were presidents (n = 26), heads of randomly chosen committees (n = 52), and randomly selected members of those committees (n = 52). Publications contributing to h-index were categorized as research articles, reviews, guidelines, metaanalyses, or other published work. Results Overall, 3259 items authored by 129 scholars were analyzed. The median h-index was 19.5. The median contribution of research articles to h-index was 84.4%. Researchers in the upper h-index tercile (≄28.5) had a larger share of research articles that contributed to h-index in comparison with those in the lower h-index tercile (≀12.5) (median 87.3% [1st-3rd quartile: 80.0%-93.1%] vs 80.0% [50.0%- 88.9%], P = 0.015). We observed an analogous difference with regard to guidelines (1.1% [0%-3.7%] vs 0% [0%-0%], P = 0.007). Conclusions Original research drives h-indices in medicine. Although guidelines contribute to h-indices in medicine, their influence is low. The specific role of randomized controlled trials in building h-index in medicine remains to be assessed

    Wood Quality in Pine Stands Damaged by Industrial Pollutants in Poland

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    Information on the impact of industrial air pollutants on forest stands aid consequences on wood quality are a little mixed up and misleading. Some experiments made on pines 130-230 years old did not reveal serious changes of wood quality. In this work, we present results of investigations on wood from 60-year-old pine trees which were under the influence of air pollutants for about 40 years. Such pine stands, of an age near the mean for the present forests in Poland, were the basis for some evaluations of financial losses in Poland due to the effects of air pollution on forests. Detailed data on the properties of the pine wood, which were the basis of the above-mentioned calculations, are also presented. The factors influencing economic losses are given based on the findings presented

    Fecal pancreatic elastase-1 levels in older individuals without known gastrointestinal diseases or diabetes mellitus

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    Background - Structural changes occur in the pancreas as a part of the natural aging process. With aging, also the incidence of maldigestive symptoms and malnutrition increases, raising the possibility that these might be caused at least in part by inadequate pancreatic enzyme secretion due to degenerative processes and damage of the gland. Fecal elastase-1 is a good marker of pancreatic exocrine secretion. The aim of this study was to investigate the fecal elastase-1 levels among over 60 years old Finnish and Polish healthy individuals without any special diet, known gastrointestinal disease, surgery or diabetes mellitus. Methods - A total of 159 patients participated in this cross-sectional study. 106 older individuals (aged 60-92 years) were recruited from outpatient clinics and elderly homes. They were divided to three age groups: 60-69 years old (n = 31); 70-79 years old (n = 38) and over 80 years old (n = 37). 53 young subjects (20-28 years old) were investigated as controls. Inclusion criteria were age over 60 years, normal status and competence. Exclusion criteria were any special diet, diabetes mellitus, any known gastrointestinal disease or prior gastrointestinal surgery. Fecal elastase-1 concentration was measured from stool samples with an ELISA that uses two monoclonal antibodies against different epitopes of human elastase-1. Results - Fecal elastase-1 concentrations correlated negatively with age (Pearson r = -0,3531, P < 0.001) and were significantly lower among subjects over 70 years old compared to controls (controls vs. 70-79 years old and controls vs. over 80 years old, both P < 0.001). Among the over 60 years old subjects, the fecal elastase-1 concentrations were below the cut off level of 200 ÎŒg/g in 23 of 106 (21.7%) individuals [mean 112 (86-138) ÎŒg/g] indicating pancreatic exocrine insufficiency. Of those, 9 subjects had fecal elastase-1 level below 100 ÎŒg/g as a marker of severe pancreatic insufficiency. Conclusion - In our study one fifth of healthy older individuals without any gastrointestinal disorder, surgery or diabetes mellitus suffer from pancreatic exocrine insufficiency and might benefit from enzyme supplementation therapy.peerReviewe

    Service encounters, experiences and the customer journey: defining the field and a call to expand our lens

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    Service researchers have emphasized the importance of studying the service experience, which encompasses multiple service encounters. Although the reflection on a series of service encounters has increased, the scope of research in this space remains narrow. Service research has traditionally concentrated on understanding, measuring and optimizing the core service delivery. While this focused lens has generated extraordinary knowledge and moved service research and practice forward, it has also resulted in a narrowly focused research field. The authors present a framework to guide comprehensive service experience research. Broadly, they define (1) pre-core service encounter, (2) core service encounter, and (3) post-core service encounter as distinct periods within a service experience. Further, they review the literature and put forward important research questions to be addressed within and across these periods. Finally, they argue that researchers need to consider simultaneously all periods of the service experience to make valuable contributions to the literature.info:eu-repo/semantics/publishedVersio

    Cultural determinants of the gap between self-estimated navigation ability and wayfinding performance: evidence from 46 countries

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    Cognitive abilities can vary widely. Some people excel in certain skills, others struggle. However, not all those who describe themselves as gifted are. One possible influence on self-estimates is the surrounding culture. Some cultures may amplify self-assurance and others cultivate humility. Past research has shown that people in different countries can be grouped into a set of consistent cultural clusters with similar values and tendencies, such as attitudes to masculinity or individualism. Here we explored whether such cultural dimensions might relate to the extent to which populations in 46 countries overestimate or underestimate their cognitive abilities in the domain of spatial navigation. Using the Sea Hero Quest navigation test and a large sample (N = 383,187) we found cultural clusters of countries tend to be similar in how they self-rate ability relative to their actual performance. Across the world population sampled, higher self-ratings were associated with better performance. However, at the national level, higher self-ratings as a nation were not associated with better performance as a nation. Germanic and Near East countries were found to be most overconfident in their abilities and Nordic countries to be most under-confident in their abilities. Gender stereotypes may play a role in mediating this pattern, with larger national positive attitudes to male stereotyped roles (Hofstede's masculinity dimension) associated with a greater overconfidence in performance at the national level. We also replicate, with higher precision than prior studies, evidence that older men tend to overestimate their navigation skill more than other groups. These findings give insight into how culture and demographics may impact self-estimates of our abilities

    Taxing construction minerals: a contribution to a resource-efficient Europe

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    This paper focuses on market incentives by the introduction of a construction minerals tax as an example of a resource tax. Currently, various European countries levy taxes or duties on primary construction materials, but a harmonisation of the taxation is not planned. Provided the tax rate has a perceptible price effect, the taxation of a resource can foster a demand management or the reduction of the raw material consumption and the governance of side and secondary effects. A construction minerals tax can target the stimulation of demand for secondary raw materials and recycled products, and—because the reuse of construction and demolition waste has technical limits—a stronger emphasis on the conservation of buildings and infrastructures. This has positive effects on the environment and the innovation efforts and it helps to internalise externalities. Germany, used as a case study in this paper, does not raise any taxes on other raw materials than energy sources at the federal level. For this reason, potential impacts of the introduction of a construction minerals tax will be explored and the results of a simulation will be provided

    Regulation of human chorionic gonadotropin beta subunit expression in ovarian cancer

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    Expression of human chorionic gonadotropin beta subunit by cancers is extensively documented, yet regulation of the multiple genes that can code for this protein is poorly understood. The aim of the study was to examine the mechanisms regulating CGB gene expression in ovarian cancer. Expression of CGB genes and SP1, SP3, TFAP2A transcription factor genes was evaluated by RT-qPCR. The methylation status of CGB genes promoter regions was examined by methylation-specific PCR. mRNA arising from multiple CGB genes was detected in both ovarian control and malignant tissues. However, expression of CGB3-9 genes was shown to be significantly higher in malignant than healthy ovarian tissues. CGB1 and CGB2 transcripts were shown to be present in 20% of ovarian cancers, but were not detected in any of the control samples. Malignant tissues were characterized by DNA demethylation of CGB promoter regions. In ovarian cancer CGB expression positively correlated with TFAP2A transcripts level and expression of TFAP2A transcription factor was significantly higher in cancer than in control tissues. In contrast SP3 expression level was significantly lower in ovarian tumours than in control ovarian tissue. In ovarian cancers increased expression of human chorionic gonadotropin beta subunit is associated with demethylation of CGB promoter regions. CGB3-9 expression level strongly correlates with expression of the TFAP2A transcription factor. Presence of mRNA arising from CGB1 and CGB2 genes appears to be a unique feature of a subset of ovarian cancers
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