Overoptimistic View Research Articles

Objective or biased? CEO overconfidence and journalists' coverage

AbstractThis study explores whether journalists report more positively or negatively on acquisitions by chief executive officers (CEOs) with greater overconfidence than those with less overconfident CEOs. The results show that journalists report acquisition events conducted by firms with overconfident CEOs more negatively than those without. Meanwhile, journalists' negativity in reporting acquisitions by overconfident CEOs is mitigated during periods of high market uncertainty. This result suggests that journalists are not biased upward because of the positive prospects presented by overconfident CEOs but instead act as information intermediaries to inform readers about the overoptimistic view of overconfident CEOs.

Universities in less developed regions: analyzing their local research impact

Abstract It is not uncommon to encounter overoptimistic views among policy-makers concerning the extent to which the research outcome of a university can have an impact on the innovation and economic performance of a local economy. Policies and expectations are usually influenced by optimal cases of top-ranked universities in highly innovative geographies. However, most universities do not function in such contexts, but in regions of weak innovation and economic development, often characterized as less developed regions (LDRs). To enrich our understanding about universities within LDRs, this study attempts to provide insights into the local research impact of a young university located within an LDR by analyzing bibliometric data. Findings show that although the university’s research output grows, there is hardly any evidence of an impact on local organizations, suggesting that the expected universities’ roles and related innovation policies should always consider the characteristics of the place within which they function.

Contrasting Characteristics and Outcomes of Sports-Related and Non–Sports-Related Traumatic Brain Injury

Exposure to traumatic brain injury (TBI) has raised widespread concern over participation in sports, particularly over possible long-term consequences. However, little is known about the outcomes of individuals presenting to hospitals with sports-related TBI. To compare the characteristics and outcomes of individuals presenting to hospitals with sports-related and non-sports-related TBI. The CENTER-TBI (Collaborative European NeuroTrauma Effectiveness Research in TBI) observational cohort study was conducted at hospitals in 18 countries. The study enrolled 4509 patients who had TBI and had an indication for computed tomography (CT), of whom 4360 were 16 years or older. Outcomes were assessed at 3 and 6 months, and groups were compared using regression analyses adjusting for clinical and demographic differences. Data were collected between December 9, 2014, and December 17, 2017, and analyzed from August 2022 to March 2023. Sports-related and non-sports-related TBI with subgroups selected by severity of injury. The main outcome was the Glasgow Outcome Scale-Extended (GOSE) at 6 months, with secondary outcomes covering postconcussion symptoms, health-related quality of life, and mental health. A total of 4360 patients were studied, including 256 (6%) with sports-related TBI (mean [SD] age, 38.9 [18.1] years; 161 [63%] male) and 4104 with non-sports-related TBI (mean [SD] age, 51.0 [20.2] years; 2773 [68%] male). Compared with patients with non-sports-related TBI, patients with sports-related TBI were younger, more likely to have tertiary education, more likely to be previously healthy, and less likely to have a major extracranial injury. After adjustment, the groups did not differ in incomplete recovery (GOSE scores <8) at 6 months (odds ratio [OR], 1.27; 95% CI, 0.90-1.78; P = .22 for all patients; OR, 1.20; 95% CI, 0.83-1.73; P = .34 for those with mild TBI; and OR, 1.19; 95% CI, 0.74-1.92; P = .65 for those with mild TBI and negative CT findings). At 6 months, there was incomplete recovery in 103 of 223 patients (46%) with outcomes in the sports-related TBI group, 65 of 168 (39%) in those with mild sports-related TBI, and 30 of 98 (31%) in those with mild sports-related TBI and negative CT findings. In contrast, at 6 months, the sports-related TBI group had lower prevalence of anxiety, depression, posttraumatic stress disorder, and postconcussion symptoms than the non-sports-related group. In this cohort study of 4360 patients with TBI, functional limitations 6 months after injury were common after sports-related TBI, even mild sports-related TBI. Persisting impairment was evident in the sports-related TBI group despite better recovery compared with non-sports-related TBI on measures of mental health and postconcussion symptoms. These findings caution against taking an overoptimistic view of outcomes after sports-related TBI, even if the initial injury appears mild.

Analysing the construction of ‘sustainability’ in lower secondary school technology syllabi in Ireland

With growing societal recognition of the need to take action in order to promote more sustainable futures, school curricula have been seen as crucial vehicles through which to promote education for sustainable development. STEM subjects in particular have been targeted as pertinent areas to best promote sustainability through curriculum development initiatives. This paper aims to explore the Irish second level educational response to the growing sustainability challenge through an analysis of the recently revised Technology Education curricula. The findings from this paper challenge the uncritical and over-optimistic views of sustainability evident within the Irish context. Furthermore, it raises questions about the ability of school curricula across any jurisdiction to respond to significant global challenges while situated within an ascendant market driven, neoliberal philosophy of education.

Attitudes of registered nurses about the end \u2013 of \u2013 life care in multi-profile hospitals: a cross sectional survey

BackgroundEnd-of-life care is provided in a variety of healthcare settings, not just palliative care hospitals. This is one reason why it is very important to assess all barriers to end-of-life care and to provide safe and quality services to patients. This study was aimed at describing nurses’ attitudes in providing end-of-life care and exploring barriers and facilitating behaviors of nurses in multi-profile hospitals in Eastern Europe.MethodsA descriptive, correlational design was applied in this study, using a cross-sectional survey of 1320 registered nurses within 7 hospitals in Lithuania.ResultsRegistered nurses working in the three different profiles emphasized safe and effective care and the importance of meeting the patient’s spiritual needs at the end of life. The main barriers assigned by nurses caring for patients at the end of life were angry family members, inadequate understanding of nursing care by the patient’s relatives; lack of time to talk to patients, lack of nursing knowledge to deal with the bereaved patient’s family, lack of evaluation of nurses’ opinions, and the evasion by physicians to talk about the diagnosis and their over-optimistic view of the situation. The main facilitating behaviors to improve nursing care were end-of-life training, volunteering, and family involvement.ConclusionsSpiritual needs were identified by nurses as the primary needs of patients at the end of life. Family-related barriers remain one of the main barriers to end-of-life care. Also, the behavior of physicians and their relationship with nurses remains one of the most sensitive issues in end-of-life care.

Validation strategy can result in an overoptimistic view of the ability of milk infrared spectra to predict methane emission of dairy cattle

Because of the environmental impact of methane (CH4), it is of great interest to reduce CH4 emission of dairy cattle and selective breeding might contribute to this. However, this approach requires a rapid and inexpensive measurement technique that can be used to quantify CH4 emission for a large number of individual dairy cows. Milk infrared (IR) spectroscopy has been proposed as a predictor for CH4 emission. In this study, we investigated the feasibility of milk IR spectra to predict breath sensor-measured CH4 of 801 dairy cows on 10 commercial farms. To evaluate the prediction equation, we used random and block cross validation. Using random cross validation, we found a validation coefficient of determination (R2val) of 0.49, which suggests that milk IR spectra are informative in predicting CH4 emission. However, based on block cross validation, with farms as blocks, a negligible R2val of 0.01 was obtained, indicating that milk IR spectra cannot be used to predict CH4 emission. Random cross validation thus results in an overoptimistic view of the ability of milk IR spectra to predict CH4 emission of dairy cows. The difference between the validation strategies could be due to the confounding of farm and date of milk IR analysis, which introduces a correlation between batch effects on the IR analyses and farm-average CH4. Breath sensor-measured CH4 is strongly influenced by farm-specific conditions, which magnifies the problem. Milk IR wavenumbers from water absorption regions, which are generally considered uninformative, showed moderate accuracy (R2val = 0.25) when based on random cross validation, but not when based on block cross validation (R2val = 0.03). These results indicate, therefore, that in the current study, random cross validation results in an overoptimistic view on the ability of milk IR spectra to predict CH4 emission. We suggest prediction based on wavenumbers from water absorption regions as a negative control to identify potential dependence structures in the data.

In vitro and in silico multidimensional modeling of oncolytic tumor virotherapy dynamics.

Tumor therapy with replication competent viruses is an exciting approach to cancer eradication where viruses are engineered to specifically infect, replicate, spread and kill tumor cells. The outcome of tumor virotherapy is complex due to the variable interactions between the cancer cell and virus populations as well as the immune response. Oncolytic viruses are highly efficient in killing tumor cells in vitro, especially in a 2D monolayer of tumor cells, their efficiency is significantly lower in a 3D environment, both in vitro and in vivo. This indicates that the spatial dimension may have a major influence on the dynamics of virus spread. We study the dynamic behavior of a spatially explicit computational model of tumor and virus interactions using a combination of in vitro 2D and 3D experimental studies to inform the models. We determine the number of nearest neighbor tumor cells in 2D (median = 6) and 3D tumor spheroids (median = 16) and how this influences virus spread and the outcome of therapy. The parameter range leading to tumor eradication is small and even harder to achieve in 3D. The lower efficiency in 3D exists despite the presence of many more adjacent cells in the 3D environment that results in a shorter time to reach equilibrium. The mean field mathematical models generally used to describe tumor virotherapy appear to provide an overoptimistic view of the outcomes of therapy. Three dimensional space provides a significant barrier to efficient and complete virus spread within tumors and needs to be explicitly taken into account for virus optimization to achieve the desired outcome of therapy.

Engines of Rebellion: Confederate Ironclads and Steam Engineering in the American Civil War by Saxon T. Bisbee

Reviewed by: Engines of Rebellion: Confederate Ironclads and Steam Engineering in the American Civil Warby Saxon T. Bisbee Thomas A. Kinney Engines of Rebellion: Confederate Ironclads and Steam Engineering in the American Civil War. By Saxon T. Bisbee. Maritime Currents: History and Archaeology. ( Tuscaloosa: University of Alabama Press, 2018. Pp. [xvi], 264. $59.95, ISBN 978-0-8173-1986-1.) Despite published studies on seemingly every conceivable aspect of the U.S. Civil War, there are yet some topics poorly understood by historians. In Engines of Rebellion: Confederate Ironclads and Steam Engineering in the American Civil War, maritime archaeologist and historian Saxon T. Bisbee takes on one of these topics, the technology and engineering of Confederate ironclads. Bisbee makes the case that Confederate ironclad building has been neglected by historians despite an abundance of extant evidence, a situation that is perhaps evidence of the chestnut that military history is written by the winners. In addition to the availability of sometimes surprisingly detailed archival resources, maritime archaeology has yielded a trove of physical artifacts. Harnessing his knowledge of both, Bisbee has studied a total of twenty-seven Confederate ironclads, those that had American-built machinery and that were actually launched, though he does include a handful of never-completed vessels featuring relatively sophisticated late-war technology. Bisbee argues that "the Confederate navy ultimately pushed the boundaries of ingenuity and changed the character of war at sea" (p. 3). Engines of Rebellionexplores this contention in a well-researched and copiously illustrated format whose chapters mirror the varied nature of ironclad vessel types. After an introductory chapter, the work proceeds through ironclad conversions and nonstandard designs, a chapter each on two sizable classes of standardized Confederate ironclads, and then on to other hull forms, [End Page 701]experimental models, and coverage of four promising but incomplete vessels. Deftly avoiding the classic pitfall of treating historical technology as a black box, Bisbee makes a concerted effort to unpack the details of nineteenth-century steam propulsion. Historians and general readers alike will benefit from the detailed glossary and the large number of illustrations that punctuate the work—even if some of the latter could be profitably enlarged. The author corrects previously misidentified equipment descriptions, ferrets out engineering drawings from private collections, and delves into some of the technicalities of the boiler explosions most historians mention only in passing. Previously ignored innovators receive similar treatment, including Confederate naval personnel such as John L. Porter, John M. Brooke, and William P. Williamson, whose collective efforts contributed so greatly to the ironclad program. Like so much of the southern side of the Civil War, however, this story abounds in questions of what might have been. Some stem from the over-optimistic views of men such as Confederate secretary of the navy Stephen Russell Mallory, whose initial hope that the Confederate navy could leverage innovative maritime technology to "overwhelm" the Union navy never came to pass (p. 5). Others emanate from an author deeply engaged with his material and sympathetic to its technical aspirations, who at times seems to claim success for a particular Confederate ironclad whose performance was at best marginal. The Confederate ironclad program was a reactive endeavor based on the necessity of combating riverine and coastal Union naval incursions, and its failure to innovate its way to victory appears inevitable given the lack of resources plaguing nearly every Confederate endeavor. The author exhibits sound scholarship and impressive detail in probing all extant corners of what ultimately proved, even in better-equipped Union and European shipyards, to be transitional technology. It should therefore come as no surprise that the much more improvised Confederate ironclads proved to be tactical disappointments and strategic dead ends. But even so, the role of ironclads in the larger evolution of nineteenth-century armored naval vessels surely deserves study. It gets that attention in abundance here. Thomas A. Kinney Bluefield College Copyright © 2019 The Southern Historical Association

Improving performance of spatio-temporal machine learning models using forward feature selection and target-oriented validation

Importance of target-oriented validation strategies for spatio-temporal prediction models is illustrated using two case studies: (1) modelling of air temperature (Tair) in Antarctica, and (2) modelling of volumetric water content (VW) for the R.J. Cook Agronomy Farm, USA. Performance of a random k-fold cross-validation (CV) was compared to three target-oriented strategies: Leave-Location-Out (LLO), Leave-Time-Out (LTO), and Leave-Location-and-Time-Out (LLTO) CV. Results indicate that considerable differences between random k-fold (R2 = 0.9 for Tair and 0.92 for VW) and target-oriented CV (LLO R2 = 0.24 for Tair and 0.49 for VW) exist, highlighting the need for target-oriented validation to avoid an overoptimistic view on models. Differences between random k-fold and target-oriented CV indicate spatial over-fitting caused by misleading variables. To decrease over-fitting, a forward feature selection in conjunction with target-oriented CV is proposed. It decreased over-fitting and simultaneously improved target-oriented performances (LLO CV R2 = 0.47 for Tair and 0.55 for VW).

Local measles vaccination gaps in Germany and the role of vaccination providers

BackgroundMeasles elimination in Europe is an urgent public health goal, yet despite the efforts of its member states, vaccination gaps and outbreaks occur. This study explores local vaccination heterogeneity in kindergartens and municipalities of a German county.MethodsData on children from mandatory school enrolment examinations in 2014/15 in Reutlingen county were used. Children with unknown vaccination status were either removed from the analysis (best case) or assumed to be unvaccinated (worst case). Vaccination data were translated into expected outbreak probabilities. Physicians and kindergartens with statistically outstanding numbers of under-vaccinated children were identified.ResultsA total of 170 (7.1%) of 2388 children did not provide a vaccination certificate; 88.3% (worst case) or 95.1% (best case) were vaccinated at least once against measles. Based on the worst case vaccination coverage, <10% of municipalities and <20% of kindergartens were sufficiently vaccinated to be protected against outbreaks. Excluding children without a vaccination certificate (best case) leads to over-optimistic views: the overall outbreak probability in case of a measles introduction lies between 39.5% (best case) and 73.0% (worst case). Four paediatricians were identified who accounted for 41 of 109 unvaccinated children and for 47 of 138 incomplete vaccinations; GPs showed significantly higher rates of missing vaccination certificates and unvaccinated or under-vaccinated children than paediatricians.ConclusionsMissing vaccination certificates pose a severe problem regarding the interpretability of vaccination data. Although the coverage for at least one measles vaccination is higher in the studied county than in most South German counties and higher than the European average, many severe and potentially dangerous vaccination gaps occur locally. If other federal German states and EU countries show similar vaccination variability, measles elimination may not succeed in Europe.

Improving patient experience in primary care: a multimethod programme of research on the measurement and improvement of patient experience

BackgroundThere has been an increased focus towards improving quality of care within the NHS in the last 15 years; as part of this, there has been an emphasis on the importance of patient feedback within policy, through National Service Frameworks and the Quality and Outcomes Framework. The development and administration of large-scale national patient surveys to gather representative data on patient experience, such as the national GP Patient Survey in primary care, has been one such initiative. However, it remains unclear how the survey is used by patients and what impact the data may have on practice.ObjectivesOur research aimed to gain insight into how different patients use surveys to record experiences of general practice; how primary care staff respond to feedback; and how to engage primary care staff in responding to feedback.MethodsWe used methods including quantitative survey analyses, focus groups, interviews, an exploratory trial and an experimental vignette study.Results(1)Understanding patient experience data. Patients readily criticised their care when reviewing consultations on video, although they were reluctant to be critical when completing questionnaires. When trained raters judged communication during a consultation to be poor, a substantial proportion of patients rated the doctor as ‘good’ or ‘very good’. Absolute scores on questionnaire surveys should be treated with caution; they may present an overoptimistic view of general practitioner (GP) care. However, relative rankings to identify GPs who are better or poorer at communicating may be acceptable, as long as statistically reliable figures are obtained. Most patients have a particular GP whom they prefer to see; however, up to 40% of people who have such a preference are unable regularly to see the doctor of their choice. Users of out-of-hours care reported worse experiences when the service was run by a commercial provider than when it was run by a not-for profit or NHS provider. (2)Understanding patient experience in minority ethnic groups. Asian respondents to the GP Patient Survey tend to be registered with practices with generally low scores, explaining about half of the difference in the poorer reported experiences of South Asian patients than white British patients. We found no evidence that South Asian patients used response scales differently. When viewing the same consultation in an experimental vignette study, South Asian respondents gave higher scores than white British respondents. This suggests that the low scores given by South Asian respondents in patient experience surveys reflect care that is genuinely worse than that experienced by their white British counterparts. We also found that service users of mixed or Asian ethnicity reported lower scores than white respondents when rating out-of-hours services. (3)Using patient experience data. We found that measuring GP–patient communication at practice level masks variation between how good individual doctors are within a practice. In general practices and in out-of-hours centres, staff were sceptical about the value of patient surveys and their ability to support service reconfiguration and quality improvement. In both settings, surveys were deemed necessary but not sufficient. Staff expressed a preference for free-text comments, as these provided more tangible, actionable data. An exploratory trial of real-time feedback (RTF) found that only 2.5% of consulting patients left feedback using touch screens in the waiting room, although more did so when reminded by staff. The representativeness of responding patients remains to be evaluated. Staff were broadly positive about using RTF, and practices valued the ability to include their own questions. Staff benefited from having a facilitated session and protected time to discuss patient feedback.ConclusionsOur findings demonstrate the importance of patient experience feedback as a means of informing NHS care, and confirm that surveys are a valuable resource for monitoring national trends in quality of care. However, surveys may be insufficient in themselves to fully capture patient feedback, and in practice GPs rarely used the results of surveys for quality improvement. The impact of patient surveys appears to be limited and effort should be invested in making the results of surveys more meaningful to practice staff. There were several limitations of this programme of research. Practice recruitment for our in-hours studies took place in two broad geographical areas, which may not be fully representative of practices nationally. Our focus was on patient experience in primary care; secondary care settings may face different challenges in implementing quality improvement initiatives driven by patient feedback. Recommendations for future research include consideration of alternative feedback methods to better support patients to identify poor care; investigation into the factors driving poorer experiences of communication in South Asian patient groups; further investigation of how best to deliver patient feedback to clinicians to engage them and to foster quality improvement; and further research to support the development and implementation of interventions aiming to improve care when deficiencies in patient experience of care are identified.FundingThe National Institute for Health Research Programme Grants for Applied Research programme.

Old Factories, New Stakhanovites: Moscow Contemporary Art-Centres as Workplaces

In the past 20 years, the increasing number of papers in cultural studies, sociology of the arts and industrial sociology has been focused on creative/cultural workers. They critically reconsidered the over-optimistic view on creative workforce presented earlier the cultural economists as R. Florida, C. Landry and others. However, there are still many topics, which remain understudied. First, most of the studies were focused on free-lancers, short contract and self-employed workers and still exclude those who are employed full-time or strongly tied with an institutional organization. Furthermore, while much research has been devoted to the UK, other regions or global concerns have gained little attention. This paper aims to bridge above mentioned gap at least partly by presenting an empirical case of full-time workers in Moscow art-centres, based on 20 in-depth interviews and 20 observations at the workplaces and public events of these centres.

Renal Denervation for Treatment of Hypertension: a Second Start and New Challenges.

Following the publication of the randomized controlled but open-label trial Symplicity HTN-2, catheter-based renal sympathetic denervation was proposed as a novel treatment for drug-resistant hypertension. Thousands of procedures were routinely performed in Europe, Australia and Asia, and many observational studies were published. A sudden shift from overoptimistic views to radical scepticism occurred later, when the large US randomized sham-controlled trial Symplicity HTN-3 failed to meet its primary blood pressure lowering efficacy endpoint. Experts are divided on the reasons accounting for the large discrepancy between the results of initial studies and those of Symplicity HTN-3. Indeed, the blood pressure lowering effect associated with renal denervation was overestimated in initial trials due to various patient and physician-related biases, whereas it could have been underestimated in Symplicity HTN-3, which was well designed but not rigorously executed. Still, there is a large consensus on the need to further study catheter-based renal denervation in more controlled conditions, with particular emphasis on identification of predictors of blood pressure response. US and European experts have recently issued very similar recommendations on design of upcoming trials, procedural aspects, drug treatment, patient population and inclusion-exclusion criteria. Application of these new standards may represent a second chance for renal denervation to demonstrate--or not--its efficacy and safety in various patient populations. With its highly standardized treatment regimen, the French trial DENERHTN paved the way for this new approach and may inspire upcoming studies testing novel renal denervation systems in different populations.

How Many Older People Are Frail? Using Multiple Imputation to Investigate Frailty in the Population

ObjectivesThe objective of this study was to establish the extent to which frailty was associated with attrition and then compare estimates of frailty prevalence and progression estimated from the observed data to those estimated after imputation. DesignPopulation-based cohort study. SettingThe Health in Men Study (HIMS) with frailty estimated at Wave 2 (2001/2004) and Wave 3 (2008) and mortality follow-up to 2010. ParticipantsParticipants were 10,305 community-dwelling men aged 70 and older, followed for up to 10 years. MeasurementsParticipants completed an extensive questionnaire covering functional activities and illnesses. Frailty was assessed using the FRAIL Scale and a 32-item Frailty Index. ResultsNonresponders at Wave 3 were more likely to have been frail at Wave 2. Imputed estimates of frailty prevalence were 8% to 10% higher than those derived from the observed data. ConclusionEpidemiological surveys may substantially underestimate the levels of frailty among older people in the general population. This selective nonresponse results in an overoptimistic view of aging populations, particularly for the very old.

Structuring the Population

Many recipes for how to do an NIR calibration begin with a step that combines rejecting outliers with splitting the available samples into calibration and validation sets. This is sometimes referred to as structuring the population, though it has other names as well. Though the aims of having clean data and a sensible split cannot be argued with, my personal view is that there is a general tendency to take things a bit too far, with the result being an over-optimistic view of how good is the resulting calibration.

Constitutional Courts as Democratic Consolidators: Insights from South Africa Twenty Years On

One of the major fault-lines running through current thinking about the role of constitutional courts in democratic consolidation has to do with the question of judicial agency. For some commentators, constitutional courts have very little capacity to act independently of their political environment. It follows that, at most, a constitutional court may be able to amplify broader trends towards democratic consolidation. In the absence of those trends, however, a court is essentially powerless, either to add to the quality of democracy or to arrest a slide back into authoritarianism. For others, constitutional courts do possess at least some measure of agency. By strategically asserting their review powers, they can build their legitimacy and become a forceful check on anti-democratic tendencies within the political system. This paper tries to find a middle path between these two views: to correct the pessimistic view by injecting into it a sense of the social-systemic distinctiveness and thus the legitimating potential of law, and to correct the overoptimistic view by emphasising the real-world constraints under which constitutional courts work. After setting out this general approach, the paper explores its explanatory power in relation to the South African case.

Salivary Cortisol in Ambulatory Assessment—Some Dos, Some Don’ts, and Some Open Questions

The impact of stress on health and disease is an important research topic in psychosomatic medicine. Because research on hypothalamic-pituitary-adrenal (HPA) axis regulation under controlled laboratory studies lacks ecological validity, it needs to be complemented by a research program that includes momentary ambulatory assessment. The measurement of salivary cortisol offers the possibility to trace the free steroid hormone concentrations in ambulant settings. Therefore, in this article, we first discuss the role of salivary cortisol in ambulatory monitoring. We start with a brief description of HPA axis regulation, and we then consider cortisol assessments in other organic materials, followed by a presentation of common salivary markers of HPA axis regulation suitable for ambulatory assessment. We further provide an overview on assessment designs and sources of variability within and between subjects (intervening variables), acknowledge the issue of (non)compliance, and address statistical aspects. We further give an overview of associations with psychosocial and health-related variables relevant for ambulatory assessment. Finally, we deal with preanalytical aspects of laboratory salivary cortisol analysis. The relative simplicity of salivary cortisol assessment protocols may lead to an overoptimistic view of the robustness of this method. We thus discuss several important issues related to the collection and storage of saliva samples and present empirical data on the stability of salivary cortisol measurements over time.

Dynamic modularity in discrete-time models of regulatory networks

We study the properties of small regulatory networks treated as non-autonomous dynamical systems, otherwise called modules when working inside larger networks. We explicit and study the conditions on the input sequences and the internal parameters of the system to behave as a transducer (finite-state automata with inputs and outputs). In the allowed families of networks, we distinguish those with and without feedback on the basis of whether the internal dynamics of the module has a role on determining their input–output behaviors or not. The input–output and non-autonomous bifurcation analysis of this class of modules rely on studying their symbolic dynamics. We consider the interplay between the internal and structural properties of the modules and the different possible inputs on them to deduce possible new functionalities as internal and external responses. Far from the over-optimistic view according to which to a module shall correspond one functionality, we obtain a trade-off between a large spectrum of behaviors and the robustness of each of them depending on the delays, non-linearities and strengths involved in the regulations.

Human assessments of document similarity

AbstractTwo studies are reported that examined the reliability of human assessments of document similarity and the association between human ratings and the results of n‐gram automatic text analysis (ATA). Human interassessor reliability (IAR) was moderate to poor. However, correlations between average human ratings and n‐gram solutions were strong. The average correlation between ATA and individual human solutions was greater than IAR. N‐gram length influenced the strength of association, but optimum string length depended on the nature of the text (technical vs. nontechnical). We conclude that the methodology applied in previous studies may have led to overoptimistic views on human reliability, but that an optimal n‐gram solution can provide a good approximation of the average human assessment of document similarity, a result that has important implications for future development of document visualization systems.

Efficient Penalty Clauses with Debiasing: Lessons from Cognitive Psychology

Efficient Penalty Clauses with Debiasing: Lessons from Cognitive Psychology