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Organisation der IT-Sicherheit in der Produktion : in zehn Schritten zur sicheren Produktionsanlage
(2018)
Der folgende Beitrag befasst sich mit der IT-Sicherheit von Produktionsanlagen aus Betreibersicht. Hierbei liegt der Fokus auf den organisatorischen Aspekten der IT-Sicherheit. In einer Bestandsaufnahme werden zunächst die Probleme herausgearbeitet, die entstehen, sofern sich eine Organisation im Wesentlichen auf technische Aspekte der IT-Sicherheit konzentriert. Daraus wird die Notwendigkeit organisatorischer Maßnahmen abgeleitet. Eine Betrachtung von Normen und Standards, die sich mit den organisatorischen Aspekten der IT-Sicherheit in der Produktion befassen, liefert das Grundgerüst für die Ableitung eines Maßnahmenplans. Der daraus resultierende 10-Punkte-Plan zur Umsetzung der IT-Sicherheit in der Produktion schließt den Beitrag ab.
Background: The topographical correlations between certain extracranial and intracranial osseous points of interest (POIs), and their age-related changes, are indispensable to know for a diagnostical or surgical access to intracranial structures; however, they are difficult to assess with conventional devices.
Materials and methods: In this pilot study, the 3-dimensional coordinates of extra-/intracranial POIs were determined, thus avoiding perspective distortions that used to be intrinsic problems in 2-dimensional morphometry. The data sets were then analysed by creating virtual triangles. The sizes, shapes, and positions of these triangles described the extent and the directions of the age-related shifts of the POIs. A selection of extracranial and intracranial POIs were marked on half skulls of four warmblood horses in two age groups (young: 6 weeks, n = 2; old: 14 and 17 years, n = 2). The x-, y-, and z-coordinates of these POIs were determined with a measurement arm (FaroArm Fusion, FARO Europe®). Direct distances between the POIs as well as their indirect distances on the x-, y-, and z-axis, and angles were calculated.
Results: The analysed virtual triangles revealed that some parts of the skull grew in size, but did not change in shape/relative proportions (proportional type of growth, as displayed by POI A and POI B at the Arcus zygomaticus). The same POIs (A and B) remained in a very stable relationship to their closest intracranial POI at the Basis cranii on the longitudinal axis, however, shifted markedly in the dorso-lateral direction. In contrast, a disproportional growth of other parts of the cranium was, for example, related to POI C at the Crista nuchae, which shifted strongly in the caudal direction with age. A topographically stable reference point (so-called anchor point) at the Basis cranii was difficult to determine.
Conclusions: Two candidates (one at the Synchondrosis intersphenoidalis, another one at the Synchondrosis sphenooccipitalis) were relatively stable in their positions. However, the epicentre of (neuro-)cranial growth could only be pinpointed to an area between them.
Toward a service-based workflow for automated information extraction from herbarium specimens
(2018)
Over the past years, herbarium collections worldwide have started to digitize millions of specimens on an industrial scale. Although the imaging costs are steadily falling, capturing the accompanying label information is still predominantly done manually and develops into the principal cost factor. In order to streamline the process of capturing herbarium specimen metadata, we specified a formal extensible workflow integrating a wide range of automated specimen image analysis services. We implemented the workflow on the basis of OpenRefine together with a plugin for handling service calls and responses. The evolving system presently covers the generation of optical character recognition (OCR) from specimen images, the identification of regions of interest in images and the extraction of meaningful information items from OCR. These implementations were developed as part of the Deutsche Forschungsgemeinschaft funded a standardised and optimised process for data acquisition from digital images of herbarium specimens (StanDAP-Herb) Project.
The objective of this study was to investigate the association between teat skin colonization and intramammary infection (IMI) with Staphylococcus aureus or Streptococcus agalactiae at the quarter level in herds with automatic milking systems. Milk and teat skin samples from 1,142 quarters were collected from 300 cows with somatic cell count >200,000 cells/mL from 8 herds positive for Strep. agalactiae. All milk and teat skin samples were cultured on calf blood agar and selective media. A subset of samples from 287 quarters was further analyzed using a PCR assay (Mastit4 PCR; DNA Diagnostic A/S, Risskov, Denmark). Bacterial culture detected Staph. aureus in 93 (8.1%) of the milk samples and 75 (6.6%) of the teat skin samples. Of these, 15 (1.3%) quarters were positive in both the teat skin and milk samples. Streptococcus agalactiae was cultured in 84 (7.4%) of the milk samples and 4 (0.35%) of the teat skin samples. Of these, 3 (0.26%) quarters were positive in both the teat skin and milk samples. The PCR detected Staph. aureus in 29 (10%) of the milk samples and 45 (16%) of the teat skin samples. Of these, 2 (0.7%) quarters were positive in both the teat skin and milk samples. Streptococcus agalactiae was detected in 40 (14%) of the milk samples and 51 (18%) of the teat skin samples. Of these, 16 (5.6%) quarters were positive in both the teat skin and milk samples. Logistic regression was used to investigate the association between teat skin colonization and IMI at the quarter level. Based on bacterial culture results, teat skin colonization with Staph. aureus resulted in 7.8 (95% confidence interval: 2.9; 20.6) times higher odds of Staph. aureus IMI, whereas herd was observed as a major confounder. However, results from the PCR analyses did not support this association. Streptococcus agalactiae was isolated from the teat skin with both PCR and bacterial culture, but the number of positive teat skin samples detected by culture was too low to proceed with further analysis. Based on the PCR results, Strep. agalactiae on teat skin resulted in 3.8 (1.4; 10.1) times higher odds of Strep. agalactiae IMI. Our results suggest that Staph. aureus and Strep. agalactiae on teat skin may be a risk factor for IMI with the same pathogens. Focus on proper teat skin hygiene is therefore recommended also in AMS.
Background: Depletion of ovarian hormone in postmenopausal women has been associated with changes in the locomotor apparatus that may compromise walking function including muscle atrophy/weakness, weight gain, and bone demineralization. Therefore, handgrip strength (HGS), bone mineral density (BMD) and body composition [percentage body fat mass (%BFM), fat mass (FM), Fat-free mass (FFM) and body mass index (BMI)], may significantly vary and predict WB in postmenopausal women. Consequently, the study sought to 1. Explore body composition, BMD and muscle strength differences between premenopausal and postmenopausal women and 2. Explore how these variables [I.e., body composition, BMD and muscle strength] relate to WB in postmenopausal women.
Method: Fifty-one pre-menopausal (35.74 + 1.52) and 50 postmenopausal (53.32 + 2.28) women were selected by convenience sampling and studied. Six explanatory variables (HGS, BMD, %BFM, FFM, BMI and FM) were explored to predict WB in postmenopausal women: Data collected were analyzed using multiple linear regression, ANCOVA, independent t-test and Pearson correlation coefficient at p < 0.05.
Result: Postmenopausal women had higher BMI(t = + 1.72; p = 0.04), %BFM(t = + 2.77; p = .003), FM(t = + 1.77; p = 0.04) and lower HGS(t = − 3.05; p = 0.001),compared to the premenopausal women. The predicted main effect of age on HGS was not significant, F(1, 197) = 0.03, p = 0.06, likewise the interaction between age and %BFM, F(1, 197) = 0.02, p = 0.89; unlike the predicted main effect of %BFM, F(1, 197) = 10.34, p = .002, on HGS. HGS was the highest predictor of WB (t = 2.203; β=0.3046) in postmenopausal women and combined with T-score right big toe (Tscorert) to produce R2 = 0.11;F (2, 47)=4.11;p = 0.02 as the best fit for the predictive model. The variance (R2) change was significant from HGS model (R2 = 0.09;p = 0.03) to HGS + Tscorert model (R2 = 0.11;p = 0.02). The regression model equation was therefore given as: WB =5.4805 + 0.1578(HGS) + (− 1.3532) Tscorert.
Conclusion: There are differences in body composition suggesting re-compartmentalization of the body, which may adversely impact the (HGS) muscle strength in postmenopausal women. Muscle strength and BMD areassociated with WB, although, only contribute to a marginal amount of the variance for WB. Therefore, other factors in addition to musculoskeletal health are necessary to mitigate fall risk in postmenopausal women.
Staphylococcus aureus is recognized worldwide as one of the major agents of dairy cow intra-mammary infections. This microorganism can express a wide spectrum of pathogenic factors used to attach, colonize, invade and infect the host. The present study evaluated 120 isolates from eight different countries that were genotyped by RS-PCR and investigated for 26 different virulence factors to increase the knowledge on the circulating genetic lineages among the cow population with mastitis. New genotypes were observed for South African strains while for all the other countries new variants of existing genotypes were detected. For each country, a specific genotypic pattern was found. Among the virulence factors, fmtB, cna, clfA and leucocidins genes were the most frequent. The sea and sei genes were present in seven out of eight countries; seh showed high frequency in South American countries (Brazil, Colombia, Argentina), while sel was harboured especially in one Mediterranean country (Tunisia). The etb, seb and see genes were not detected in any of the isolates, while only two isolates were MRSA (Germany and Italy) confirming the low diffusion of methicillin resistance microorganism among bovine mastitis isolates. This work demonstrated the wide variety of S. aureus genotypes found in dairy cattle worldwide. This condition suggests that considering the region of interest might help to formulate strategies for reducing the infection spreading.
A nonblinded, positively controlled, noninferiority trial was conducted to evaluate the efficacy of an alternative, nonantibiotic therapy with Masti Veyxym® to reduce ineffective antibiotic usage in the treatment of nonsevere clinical mastitis (CM) in cows with longer lasting udder diseases. The solely intramammary treatment with Masti Veyxym® (three applications, 12 hr apart) and the combined treatment with Masti Veyxym® and antibiotics as usual on the farm according to label of the respective product were compared with the reference treatment of solely antibiotic therapy. The matched field study was conducted on eight free-stall dairy farms located in Eastern Germany. Cases of mild-to-moderate CM in cows with longer lasting high somatic cell counts in preceding dairy herd improvement test days and with previous CM cases in current lactation were randomly allocated to one of the three treatment groups. A foremilk sample of the affected quarter was taken before treatment and again approximately 14 days and 21 days after the end of therapy for cyto-bacteriological examination. Primary outcomes were clinical cure (CC) and no CM recurrence within 60 days after the end of treatment (no R60). Bacteriological cure (BC) and quarter somatic cell count (QSCC) cure were chosen as secondary outcomes although low probabilities of BC and QSCC cure for selected cows were expected. The study resulted in the following findings: the pathogens mostly cultured from pretreatment samples were Streptococcus uberis, followed by Staphylococcus aureus and coagulase-negative staphylococci. There were no significant differences between the two test treatments in comparison with the reference treatment regarding all outcome variables. The sole therapy with Masti Veyxym® resulted in a numerically lower likelihood of BC without significant differences to the reference treatment. The combined therapy group showed a numerically higher nonrecurrence rate than the two other treatment groups and noninferiority compared to the reference treatment was proven. Having regard to the selection criteria of cows in this study, the findings indicated that sole treatment with Masti Veyxym® in nonsevere CM cases may constitute an alternative therapy to reduce antibiotics. However, noninferiority evaluations were mostly inconclusive. Further investigations with a larger sample size are required to confirm the results and to make a clear statement on noninferiority.
Für die Studiengang-Auswahl existiert eine Reihe i. d. R. Fragebogen-gestützter Online-Studiengangfinder. Eine Analyse zeigte Optimierungspotenziale: Studienangebote sind meist auf ein Bundesland oder eine Hochschule beschränkt oder, allgemein beschrieben, die individuelle Studiengang-Auswahl ist nur mit Unschärfen möglich. Letzteres wirkt sich z. B. bei Bindestrich-Studiengängen (z. B. Wirtschaftsingenieurwesen) aus, die je nach Hochschule inhaltlich variieren können. Hier setzt das Portal an. Ziele sind: Bereitstellung der in der Sprachwelt Studieninteressierter gehaltenen Fragebögen, Möglichkeit für Hochschulen/Einrichtungen, Studiengänge bereitzustellen.
Background: Given both the increase of nursing home residents forecast and challenges of current interprofessional interactions, we developed and tested measures to improve collaboration and communication between nurses and general practitioners (GPs) in this setting. Our multicentre study has been funded by the German Federal Ministry of Education and Research (FK 01GY1124).
Methods: The measures were developed iteratively in a continuous process, which is the focus of this article. In part 1 “exploration of the situation”, interviews were conducted with GPs, nurses, nursing home residents and their relatives focusing on interprofessional interactions and medical care. They were analysed qualitatively. Based on these results, in part 2 “development of measures to improve collaboration”, ideas for improvement were developed in nine focus groups with GPs and nurses. These ideas were revisited in a final expert workshop. We analysed the focus groups and expert workshop using mind mapping methods, and finally drew up the compilation of measures. In an exploratory pilot study "study part 3" four nursing homes chose the measures they wanted to adopt. These were tested for three months. Feasibility and acceptance of the measures were evaluated via guideline interviews with the stakeholders which were analysed by content analyses.
Results: Six measures were generated: meetings to establish common goals, main contact person, standardised pro re nata medication, introduction of name badges, improved availability of nurse/GP and standardised scheduling/ procedure for nursing home visits. In the pilot study, the measures were implemented in four nursing homes. GPs and nurses reviewed five measures as feasible and acceptable, only the designation of a “main contact person” was not considered as an improvement.
Conclusions: Six measures to improve collaboration and communication could be compiled in a multistep qualitative process respecting the perspectives of involved stakeholders. Five of the six measures were positively assessed in an exploratory pilot study. They could easily be transferred into the daily routine of other nursing homes, as no special models have to exist in advance. Impact of the measures on patient oriented outcomes should be examined in further research.
Trial registration: Not applicable.
Delphi is a frequently used research method in the information systems (IS) field. The last fifteen years have seen many variants of the Delphi Method proposed and used in IS research. However, these variants do not seem to be properly derived; while all variants share certain characteristics, their reasoning for differentiation inconsistently varies. It seems that researchers tend to create “new” Delphi Method variants, although the underlying modification of the Delphi Method is, in fact, minor. This leads to a heterogeneity of Delphi Method variants and undermines scientific rigor when using Delphi. The study addresses this deficit and (1) identifies different variants of Delphi and determines their characteristics, (2) critically reflects to what extent a clear distinction between these variants exists, (3) shows the clearly distinguishable Delphi Method variants and their characteristics, (4) develops a proposed taxonomy of Delphi Method variants, and (5) evaluates and applies this taxonomy. The proposed taxonomy helps clearly differentiate Delphi Method variants and enhances methodological rigor when using the Delphi Method.
Objectives:
The aim was to identify theoretically expected as well as actually reported benefits from drug development and the importance of individual patient benefits compared to the collective benefits to society in general.
Background:
Ethical guidelines require that clinical research involving humans offer the potential for benefit. A number of characteristics can be applied to define research benefit. Often benefit is categorized as being either direct or indirect. Indirect benefits can involve collective benefits for society rather than any benefits to the trial patient or subject. The purpose of this review was to examine which potential individual and societal benefits were mentioned as being expected in publications from government experts and which were mentioned in publications describing completed drug development trial results.
Methods:
Literature on research benefit was first identified by searching the PubMed database using several combinations of the key words benefit and clinical research. The search was limited to articles published in English. A Google search with the same combinations of key words but without any language limitation was then performed. Additionally, the reference lists of promising articles were screened for further thematically related articles. Finally, a narrative review was performed of relevant English- and German-language articles published between 1996 and 2016 to identify which of several potential benefits were either theoretically expected or which were mentioned in publications on clinical drug development trial results.
Results:
The principal benefits from drug development discussed included 2 main types of benefit, namely individual benefits for the patients and collective benefits for society. Twenty-one of an overall total of 26 articles discussing theoretically expected benefits focused on individual patient benefits, whereas 17 out of 26 articles mentioned collective benefits to society. In these publications, the most commonly mentioned theoretically expected individual patient benefit was the chance to receive up-to-date care (38.1%). A general increase in knowledge about health care, treatments, or drugs (70.6%) was the most commonly mentioned theoretically expected benefit for society. In contrast, all 13 publications reporting actual benefits of clinical drug development trials focused on personal benefits and only 1 of these publications also mentioned a societal benefit. The most commonly mentioned individual benefit was an increased quality of life (53.9%), whereas the only mentioned collective benefit to society was a general gain of knowledge (100.0%).
Conclusions:
Both theoretically expected and actually reported benefits in the majority of the included publications emphasized the importance of individual patient benefits from drug development rather than the collective benefits to society in general. The authors of these publications emphasized the right of each individual patient or subject to look for and expect some personal benefit from participating in a clinical trial rather than considering societal benefit as a top priority. From an ethical point of view, the benefits each individual patient receives from his or her participation in a clinical trial might also be seen as a societal benefit, especially when the drug or device tested, if approved for marketing, would eventually be made available for other similar patients from the country in which the clinical trial was conducted.
Roads to Health in Developing Countries: Understanding the Intersection of Culture and Healing
(2017)
Background:
The most important attribute to which all human beings aspire is good health because it enables us to undertake different forms of activities of daily living. The emergence of scientific knowledge in Western societies has enabled scientists to explore and define several parameters of health by drawing boundaries around factors that are known to influence the attainment of good health. For example, the World Health Organization defined health by taking physical and psychological factors into consideration. Their definition of health also included a caveat that says, “not merely the absence of sickness.”
This definition has guided scientists and health care providers in the Western world in the development of health care programs in non-Western societies.
Objective:
However, ethnomedical beliefs about the cause(s) of illness have given rise to alternative theories of health, sickness, and treatment approaches in the developing world. Thus, there is another side to the story.
Method:
Much of the population in developing countries lives in rural settings where the knowledge of health, sickness, and care has evolved over centuries of practice and experience. The definition of health in these settings tends to orient toward cultural beliefs, traditional practices, and social relationships. Invariably, whereas biomedicine is the dominant medical system in Western societies, traditional medicine — or ethno-medicine — is often the first port of call for patients in developing countries.
Results:
The 2 medical systems represent, and are influenced by, the cultural environment in which they exist. On one hand, biomedicine is very effective in the treatment of objective, measurable disease conditions. On the other hand, ethnomedicine is effective in the management of illness conditions or the experience of disease states. Nevertheless, an attempt to supplant 1 system of care with another from a different cultural environment could pose enormous challenges in non-Western societies.
Conclusion:
In general, we, as human beings, are guided in our health care decisions by past experiences, family and friends, social networks, cultural beliefs, customs, tradition, professional knowledge, and intuition. No medical system has been shown to address all of these elements; hence, the need for collaboration, acceptance, and partnership between all systems of care in cultural communities. In developing countries, the roads to health are incomplete without an examination of the intersection of culture and healing. Perhaps mutual exclusiveness rather inclusiveness of these 2 dominant health systems is the greatest obstacle to health in developing countries.
Objective: To evaluate the impact of different dissemination channels on the awareness and usage of hospital performance reports among referring physicians, as well as the usefulness of such reports from the referring physicians’ perspective.
Data sources/Study setting: Primary data collected from a survey with 277 referring physicians (response rate = 26.2%) in Nuremberg, Germany (03–06/2016).
Study design: Cluster-randomised controlled trial at the practice level. Physician practices were randomly assigned to one of two conditions: (1) physicians in the control arm could become aware of the performance reports via mass media channels (Mass Media, npr MM=132, nph MM=147); (2) physicians in the intervention arm also received a printed version of the report via mail (Mass and Special Media, npr MSM=117; nph MSM=130). <br> Principal findings: Overall, 68% of respondents recalled hospital performance reports and 21% used them for referral decisions. Physicians from the Mass and Special Media group were more likely to be aware of the performance reports (OR 4.16; 95% CI 2.16–8.00, p < .001) but not more likely to be influenced when referring patients into hospitals (OR 1.73; 95% CI 0.72–4.12, p > .05). On a 1 (very good) to 6 (insufficient) scale, the usefulness of the performance reports was rated 3.67 (±1.40). Aggregated presentation formats were rated more helpful than detailed hospital quality information.
Conclusions: Hospital quality reports have limited impact on referral practices. To increase the latter, concerns raised by referring physicians must be given more weight. Those principally refer to the underlying data, the design of the reports, and the lack of important information.
Background: Physician-rating websites (PRWs) may lead to quality improvements in case they enable and establish a peer-to-peer communication between patients and physicians. Yet, we know little about whether and how physicians respond on the Web to patient ratings.
Objective: The objective of this study was to describe trends in physicians’ Web-based responses to patient ratings over time, to identify what physician characteristics influence Web-based responses, and to examine the topics physicians are likely to respond to.
Methods: We analyzed physician responses to more than 1 million patient ratings displayed on the German PRW, jameda, from 2010 to 2015. Quantitative analysis contained chi-square analyses and the Mann-Whitney U test. Quantitative content techniques were applied to determine the topics physicians respond to based on a randomly selected sample of 600 Web-based ratings and corresponding physician responses.
Results: Overall, physicians responded to 1.58% (16,640/1,052,347) of all Web-based ratings, with an increasing trend over time from 0.70% (157/22,355) in 2010 to 1.88% (6377/339,919) in 2015. Web-based ratings that were responded to had significantly worse rating results than ratings that were not responded to (2.15 vs 1.74, P<.001). Physicians who respond on the Web to patient ratings differ significantly from nonresponders regarding several characteristics such as gender and patient recommendation results (P<.001 each). Regarding scaled-survey rating elements, physicians were most likely to respond to the waiting time within the practice (19.4%, 99/509) and the time spent with the patient (18.3%, 110/600). Almost one-third of topics in narrative comments were answered by the physicians (30.66%, 382/1246).
Conclusions: So far, only a minority of physicians have taken the chance to respond on the Web to patient ratings. This is likely because of (1) the low awareness of PRWs among physicians, (2) the fact that only a few PRWs enable physicians to respond on the Web to patient ratings, and (3) the lack of an active moderator to establish peer-to-peer communication. PRW providers should foster more frequent communication between the patient and the physician and encourage physicians to respond on the Web to patient ratings. Further research is needed to learn more about the motivation of physicians to respond or not respond to Web-based patient ratings.
For indexing archived documents the Dutch Parliament uses a specialized thesaurus. For good results for full text retrieval and automatic classification it turns out to be important to add more synonyms to the existing thesaurus terms. In the present work we investigate the possibilities to find synonyms for terms of the parliaments thesaurus automatically. We propose to use distributional similarity (DS). In an experiment with pairs of synonyms and non-synonyms we train and test a classifier using distributional similarity and string similarity. Using ten-fold cross validation we were able to classify 75% of the pairs of a set of 6000 word pairs correctly.
A systematic review of the literature on survey questionnaires to assess self-medication practices
(2017)
Self-medication is of great public health importance as it often bypasses regulatory mechanisms to assure quality of health care. Nevertheless there are no established standards on how to assess self-medication. We therefore intended to systematically retrieve questionnaires and survey tools used to capture self-medication, with the aim to identify the scope of information investigated in this context and commonalities between the tools. We conducted a systematic review of the literature on questionnaires used for self-medication assessment by searching PubMed and Web of Science databases using the combinations of following keywords; self-medication, self-prescription, non-prescription, questionnaire. Truncation was used to ensure retrieval of all possible variations of search terms. The search was limited to articles published between 1st January 2000 and 31st December 2015, human studies and English language. Duplicate and irrelevant studies were excluded from the final review. A total of 158 studies were included in the review. Studies were from diverse geographical locations, most of the studies were from Nigeria 16 (10.1%) followed by India 10 (6.3%) and Iran 8 (5%). Forty-three studies (27.2%) focused on antibiotic self-medication. Majority of the studies (106; 67%) were done with adult populations. The components addressed by the questionnaires covered: reasons for self-medications in 147 (93%) studies, purchasing source in 136 (86%) studies, medical conditions to be treated in 153 (96.8%) studies, adverse events in 67 (42.4%) studies, use of prescribing information in 24 (15.1%) studies and antibiotic resistance awareness in 20 (46.5%) antibiotic studies. For 74 (46.8%) studies, survey questionnaires were self-administered and most studies (57; 36%) were done at homes of respondents. Thirty-seven (23.4%) studies did not report any recall period for self-medication practices. Study response rates varied from 17.9% to 100%, and while validity of the study questionnaire was reported for 100 (63.3%) studies, 15 (9.5%) studies reported reliability test of the study questionnaire. There is a large variety of questionnaires being used for investigating self-medication practices making comparability and meta-analyses very difficult. It is desirable to have a basic set of standardized survey questions on this topic to make available for future research groups in this field.
Antimicrobial resistance in livestock is a matter of general concern. To develop hygiene measures and methods for resistance prevention and control, epidemiological studies on a population level are needed to detect factors associated with antimicrobial resistance in livestock holdings. In general, regression models are used to describe these relationships between environmental factors and resistance outcome. Besides the study design, the correlation structures of the different outcomes of antibiotic resistance and structural zero measurements on the resistance outcome as well as on the exposure side are challenges for the epidemiological model building process. The use of appropriate regression models that acknowledge these complexities is essential to assure valid epidemiological interpretations. The aims of this paper are (i) to explain the model building process comparing several competing models for count data (negative binomial model, quasi-Poisson model, zero-inflated model, and hurdle model) and (ii) to compare these models using data from a cross-sectional study on antibiotic resistance in animal husbandry. These goals are essential to evaluate which model is most suitable to identify potential prevention measures. The dataset used as an example in our analyses was generated initially to study the prevalence and associated factors for the appearance of cefotaxime-resistant Escherichia coli in 48 German fattening pig farms. For each farm, the outcome was the count of samples with resistant bacteria. There was almost no overdispersion and only moderate evidence of excess zeros in the data. Our analyses show that it is essential to evaluate regression models in studies analyzing the relationship between environmental factors and antibiotic resistances in livestock. After model comparison based on evaluation of model predictions, Akaike information criterion, and Pearson residuals, here the hurdle model was judged to be the most appropriate model.
Background: Fall events contribute significantly to mortality, morbidity and costs in our ageing population. In order to identify persons at risk and to target preventive measures, many scores and assessment tools have been developed. These often require expertise and are costly to implement. Recent research investigates the use of wearable inertial sensors to provide objective data on motion features which can be used to assess individual fall risk automatically. So far it is unknown how well this new method performs in comparison with conventional fall risk assessment tools. The aim of our research is to compare the predictive performance of our new sensor-based method with conventional and established methods, based on prospective data.
Methods: In a first study phase, 119 inpatients of a geriatric clinic took part in motion measurements using a wireless triaxial accelerometer during a Timed Up&Go (TUG) test and a 20 m walk. Furthermore, the St. Thomas Risk Assessment Tool in Falling Elderly Inpatients (STRATIFY) was performed, and the multidisciplinary geriatric care team estimated the patients’ fall risk. In a second follow-up phase of the study, 46 of the participants were interviewed after one year, including a fall and activity assessment. The predictive performances of the TUG, the STRATIFY and team scores are compared. Furthermore, two automatically induced logistic regression models based on conventional clinical and assessment data (CONV) as well as sensor data (SENSOR) are matched.
Results: Among the risk assessment scores, the geriatric team score (sensitivity 56%, specificity 80%) outperforms STRATIFY and TUG. The induced logistic regression models CONV and SENSOR achieve similar performance values (sensitivity 68%/58%, specificity 74%/78%, AUC 0.74/0.72, +LR 2.64/2.61). Both models are able to identify more persons at risk than the simple scores.
Conclusions: Sensor-based objective measurements of motion parameters in geriatric patients can be used to assess individual fall risk, and our prediction model’s performance matches that of a model based on conventional clinical and assessment data. Sensor-based measurements using a small wearable device may contribute significant information to conventional methods and are feasible in an unsupervised setting. More prospective research is needed to assess the cost-benefit relation of our approach.
Background: In many research areas it is necessary to find differences between treatment groups with several variables. For example, studies of microarray data seek to find a significant difference in location parameters from zero or one for ratios thereof for each variable. However, in some studies a significant deviation of the difference in locations from zero (or 1 in terms of the ratio) is biologically meaningless. A relevant difference or ratio is sought in such cases.
Results: This article addresses the use of relevance-shifted tests on ratios for a multivariate parallel two-sample group design. Two empirical procedures are proposed which embed the relevanceshifted test on ratios. As both procedures test a hypothesis for each variable, the resulting multiple testing problem has to be considered. Hence, the procedures include a multiplicity correction. Both procedures are extensions of available procedures for point null hypotheses achieving exact control of the familywise error rate. Whereas the shift of the null hypothesis alone would give straight-forward solutions, the problems that are the reason for the empirical considerations discussed here arise by the fact that the shift is considered in both directions and the whole parameter space in between these two limits has to be accepted as null hypothesis.
Conclusion: The first algorithm to be discussed uses a permutation algorithm, and is appropriate for designs with a moderately large number of observations. However, many experiments have limited sample sizes. Then the second procedure might be more appropriate, where multiplicity is corrected according to a concept of data-driven order of hypotheses.