Statistical hypothesis testing and common misinterpretations: should we abandon p-value in forensic science applications?

Many people regard the concept of hypothesis testing as fundamental to inferential statistics. Various schools of thought, in particular frequentist and Bayesian, have promoted radically different solutions for taking a decision about the plausibility of competing hypotheses. Comprehensive philosophical comparisons about their advantages and drawbacks are widely available and continue to span over large debates in the literature. More recently, controversial discussion was initiated by an editorial decision of a scientific journal [1] to refuse any paper submitted for publication containing null hypothesis testing procedures. Since the large majority of papers published in forensic journals propose the evaluation of statistical evidence based on the so called p-values, it is of interest to expose the discussion of this journal's decision within the forensic science community. This paper aims to provide forensic science researchers with a primer on the main concepts and their implications for making informed methodological choices.

Comparing Etest and Broth Microdilution for Antifungal Susceptibility Testing of the Most-Relevant Pathogenic Molds.

Invasive mold infections are life-threatening diseases for which appropriate antifungal therapy is crucial. Their epidemiology is evolving, with the emergence of triazole-resistant Aspergillus spp. and multidrug-resistant non-Aspergillus molds. Despite the lack of interpretive criteria, antifungal susceptibility testing of molds may be useful in guiding antifungal therapy. The standard broth microdilution method (BMD) is demanding and requires expertise. We assessed the performance of a commercialized gradient diffusion method (Etest method) as an alternative to BMD. The MICs or minimal effective concentrations (MECs) of amphotericin B, voriconazole, posaconazole, caspofungin, and micafungin were assessed for 290 clinical isolates of the most representative pathogenic molds (154 Aspergillus and 136 non-Aspergillus isolates) with the BMD and Etest methods. Essential agreements (EAs) within ±2 dilutions of ≥90% between the two methods were considered acceptable. EAs for amphotericin B and voriconazole were >90% for most potentially susceptible species. For posaconazole, the correlation was acceptable for Mucoromycotina but Etest MIC values were consistently lower for Aspergillus spp. (EAs of <90%). Excellent EAs were found for echinocandins with highly susceptible (MECs of <0.015 μg/ml) or intrinsically resistant (MECs of >16 μg/ml) strains. However, MEC determinations lacked consistency between methods for strains exhibiting mid-range MECs for echinocandins. We concluded that the Etest method is an appropriate alternative to BMD for antifungal susceptibility testing of molds under specific circumstances, including testing with amphotericin B or triazoles for non-Aspergillus molds (Mucoromycotina and Fusarium spp.). Additional study of molecularly characterized triazole-resistant Aspergillus isolates is required to confirm the ability of the Etest method to detect voriconazole and posaconazole resistance among Aspergillus spp.

Serious games for rehabilitation using head-mounted display and haptic devices

In the health domain, the field of rehabilitation suffers from a lack specialized staff while hospital costs only increase. Worse, almost no tools are dedicated to motivate patients or help the personnel to carry out monitoring of therapeutic exercises. This paper demonstrates the high potential that can bring the virtual reality with a platform of serious games for the rehabilitation of the legs involving a head-mounted display and haptic robot devices. We first introduce SG principles and the current context regarding rehabilitation interventions followed by the description of an original haptic device called Lambda Health System. The architecture of the model is then detailed, including communication specifications showing that lag is imperceptible for user (60Hz). Finally, four serious games for rehabilitation using haptic robots and/or HMD were tested by 33 health specialists.

Emergent patterns of social organization in captive Cercocebus torquatus: Testing the GrooFiWorld agent-based model

We empirically applied the GrooFiWorld agent-based model (Puga-González et al. 2009) in a group of captive mangabeys (Cercocebus torquatus). We analysed several measurements related to aggression and affiliative patterns. The group adopted a combination of despotic and egalitarian behaviours resulting from the behavioural flexibility observed in the Cercopithecinae subfamily. Our study also demonstrates that the GrooFiWorld agent-based model can be extended to other members of the Cercopithecinae subfamily generating parsimonious hypotheses related to the social organization.

A new alternative method for testing skin irritation using a fresh human skin model

La dermatite irritative est décrite comme une réaction réversible, non immunologique caractérisée par des lésions d'aspect très variable, allant de la simple rougeur jusqu'à la formation de bulles voire d'une nécrose, accompagnée de prurit ou d'une sensation de brûlure suite à I' application d'une substance chimique. Le teste de prédiction d'irritation cutanée est traditionnellement depuis les années 1940 le Test de Draize. Ce test consiste en l'application d'une substance chimique sur une peau rasée de lapin pendant 4h et de regarder à 24h si des signes cliniques d'irritations sont présents. Cette méthode critiquable autant d'un point de vue éthique que qualitative reste actuellement le teste le plus utilisé. Depuis le début des années 2000 de nouvelles méthodes in vitro se sont développées tel que le model d'épiderme humain recombiné (RHE). Il s agit d'une multicouche de kératinocyte bien différencié obtenu depuis une culture de don d'ovocyte. Cependant cette méthode en plus d'être très couteuse n'obtient au mieux que 76% de résultat similaire comparé au test in vivo humain. Il existe donc la nécessité de développer une nouvelle méthode in vitro qui simulerait encore mieux la réalité anatomique et physiologique retrouvée in vivo. Notre objectif a été de développer cette nouvelle méthode in vitro. Pour cela nous avons travaillé avec de la peau humaine directement prélevée après une abdominoplastie. Celle ci après préparation avec un dermatome, un couteau dont la lame est réglable pour découper l'épaisseur souhaitée de peau, est montée dans un système de diffusion cellulaire. La couche cornée est alors exposée de manière optimale à 1 ml de la substance chimique testée pendant 4h. L'échantillon de peau est alors fixé dans du formaldéhyde pour permettre la préparation de lames standards d'hématoxyline et éosine. L'irritation est alors investiguée selon des critères histopathologiques de spongioses, de nécroses et de vacuolisations cellulaires. Les résultats de ce.tte première batterie de testes sont plus que prometteurs. En effet, comparé au résultat in vivo, nous obtenons 100% de concordance pour les 4 même substances testes irritantes ou non irritantes, ce qui est supérieur au model d épiderme humain recombiné (76%). De plus le coefficient de variation entre les 3 différentes séries est inférieur à 0.1 ce qui montre une bonne reproductibilité dans un même laboratoire. Dans le futur cette méthode va devoir être testée avec un plus grand nombre de substances chimiques et sa reproductibilité évaluée dans différents laboratoires. Mais cette première evaluation, très encourageante, ouvre des pistes précieuses pour l'avenir des tests irritatifs.

Preparation of a blood culture pellet for rapid bacterial identification and antibiotic susceptibility testing.

Bloodstream infections and sepsis are a major cause of morbidity and mortality. The successful outcome of patients suffering from bacteremia depends on a rapid identification of the infectious agent to guide optimal antibiotic treatment. The analysis of Gram stains from positive blood culture can be rapidly conducted and already significantly impact the antibiotic regimen. However, the accurate identification of the infectious agent is still required to establish the optimal targeted treatment. We present here a simple and fast bacterial pellet preparation from a positive blood culture that can be used as a sample for several essential downstream applications such as identification by MALDI-TOF MS, antibiotic susceptibility testing (AST) by disc diffusion assay or automated AST systems and by automated PCR-based diagnostic testing. The performance of these different identification and AST systems applied directly on the blood culture bacterial pellets is very similar to the performance normally obtained from isolated colonies grown on agar plates. Compared to conventional approaches, the rapid acquisition of a bacterial pellet significantly reduces the time to report both identification and AST. Thus, following blood culture positivity, identification by MALDI-TOF can be reported within less than 1 hr whereas results of AST by automated AST systems or disc diffusion assays within 8 to 18 hr, respectively. Similarly, the results of a rapid PCR-based assay can be communicated to the clinicians less than 2 hr following the report of a bacteremia. Together, these results demonstrate that the rapid preparation of a blood culture bacterial pellet has a significant impact on the identification and AST turnaround time and thus on the successful outcome of patients suffering from bloodstream infections.

Student Journalism 2.0 : Testing Models for Participatory Learning in the Digital Age

Many educators and educational institutions have yet to integrate web-based practices into their classrooms and curricula. As a result, it can be difficult to prototype and evaluate approaches to transforming classrooms from static endpoints to dynamic, content-creating nodes in the online information ecosystem. But many scholastic journalism programs have already embraced the capabilities of the Internet for virtual collaboration, dissemination, and reader participation. Because of this, scholastic journalism can act as a test-bed for integrating web-based sharing and collaboration practices into classrooms. Student Journalism 2.0 was a research project to integrate open copyright licenses into two scholastic journalism programs, to document outcomes, and to identify recommendations and remaining challenges for similar integrations. Video and audio recordings of two participating high school journalism programs informed the research. In describing the steps of our integration process, we note some important legal, technical, and social challenges. Legal worries such as uncertainty over copyright ownership could lead districts and administrators to disallow open licensing of student work. Publication platforms among journalism classrooms are far from standardized, making any integration of new technologies and practices difficult to achieve at scale. And teachers and students face challenges re-conceptualizing the role their class work can play online.

Conworx POCceleratoretävalvontaohjelma vierianalytiikan kehittäjänä

Vierianalytiikan (POCT = point-of-care testing) käyttäjämäärien lisääntyminen, resurssien puute ja kiire osastoilla lisäävät virhemahdollisuuksia vierianalytiikassa. Saksalainen Conworx yhtiö on kehittänyt vierianalytiikan ongelmien ehkäisyyn POCcelerator etävalvontaohjelman. Ohjelmaan saadaan yhdistettyä useimmat käytössä olevat vierianalytiikkalaitteet ja sen avulla voidaan valvoa laitteita, käyttäjiä, tarvikkeiden kulutusta ja kontrolleja. Tässä työssä arvioitiin POCcelerator etävalvontaohjelman toimittajan lupaamien toimintojen toteutumista projektiin osallistuvilla laitteilla. Projektissa tarkasteltiin ohjelman toimittajan ilmoittamien osakokonaisuuksien toimivuutta kolmella eri laitetyypillä, jotka sijaitsivat neljällä eri osastolla. Projektissa olivat mukana Radiometerin ABL 725 ja ABL 825 verikaasuanalysaattorit sekä kuusi i-Stat laitetta, joista viidellä määritettiin verikaasuja ja yhdellä INR arvoja. Toimivuutta tarkasteltiin seuraamalla tietojen siirtymistä etäohjelmaan ja vertailemalla virheilmoituksia primäärilaitteen ja etäohjelman välillä. Etävalvontaohjelmaprojektin yhteydessä toteutettiin myös kysely projektiin osallistuvilla osastoilla. Kyselyn avulla pyrittiin arvioimaan POCcelerator etävalvontaohjelman sopivuutta ja vierianalytiikan käytänteitä projektiin osallistuvilla osastoilla. Kaikki potilastulokset siirtyivät hyvin POCcelerator etävalvontaohjelmaan kaikilta projektissa mukana olleilta laitteilta. Kontrollitulokset siirtyivät kontrollitiedostoon ABL analysaattoreilta, mutta i-Stat laitteilta siirtyi vain elektroninen kontrollitulos. Potilaan identifiointi ja käyttäjän kirjautuminen viivakoodilla siirtyi hyvin kaikilta laitteilta etävalvontaohjelmaan. Kyselytutkimuksesta saatujen tulosten mukaan vierianalytiikkalaitteiden käyttö on helppoa, mutta päivittäisiä huoltoja ei kovin hyvin hallita. Etävalvontaohjelmalla ei nähty olevan apua vierianalytiikka toimintaan osastoilla. Laboratoriosta halutaan apua tarvittaessa ja lisää koulutusta laitteiden käytöstä. POCcelerator etävalvontaohjelma sisältää HUSLABin edellyttämät etävalvontaohjelman vaatimukset, mutta laboratoriosta käsin ei ole mahdollista saada ABL analysaattoreita esim. pesemään tai ajamaan kontrollinäytettä (Remote control). Tämä ominaisuus koetaan välttämättömäksi etävalvontaohjelmalle.

Conceptual Design of Embedded Weather Display

The objective of this thesis work is to describe the Conceptual Design process of an embedded electronic display device. The work presents the following sub processes: definition of device specifications, introduction to the technological alternatives for system components and their comparison, comparative photometric measurements of selected display panels, and the design and building of a functional concept prototype. This work focuses mainly on electronics design, albeit the mechanical issues and fields of the software architecture that significantly affect the decisions are also discussed when necessary. The VESA Flat Panel Display Measurement (FPDM) 2.0 Standard was applied to the appropriate extent into photometric measurements. The results were analyzed against the requirement standards of a customer-specific display development project. An Active Matrix LCD was selected as the display of concept prototype, but also the excellent visual characteristics of Active Matrix OLED technology were noted. Should the reliability of the OLED products be significantly improved in the future, utilizing such products in the described application must be reconsidered.

Food Safety Testing: Rapid Molecular Methods for Chemical and Biological Hazards

The central goal of food safety policy in the European Union (EU) is to protect consumer health by guaranteeing a high level of food safety throughout the food chain. This goal can in part be achieved by testing foodstuffs for the presence of various chemical and biological hazards. The aim of this study was to facilitate food safety testing by providing rapid and user-friendly methods for the detection of particular food-related hazards. Heterogeneous competitive time-resolved fluoroimmunoassays were developed for the detection of selected veterinary residues, that is coccidiostat residues, in eggs and chicken liver. After a simplified sample preparation procedure, the immunoassays were performed either in manual format with dissociation-enhanced measurement or in automated format with pre-dried assay reagents and surface measurement. Although the assays were primarily designed for screening purposes providing only qualitative results, they could also be used in a quantitative mode. All the developed assays had good performance characteristics enabling reliable screening of samples at concentration levels required by the authorities. A novel polymerase chain reaction (PCR)-based assay system was developed for the detection of Salmonella spp. in food. The sample preparation included a short non-selective pre-enrichment step, after which the target cells were collected with immunomagnetic beads and applied to PCR reaction vessels containing all the reagents required for the assay in dry form. The homogeneous PCR assay was performed with a novel instrument platform, GenomEra^™, and the qualitative assay results were automatically interpreted based on end-point time-resolved fluorescence measurements and cut-off values. The assay was validated using various food matrices spiked with sub-lethally injured Salmonella cells at levels of 1-10 colony forming units (CFU)/25 g of food. The main advantage of the system was the exceptionally short time to result; the entire process starting from the pre-enrichment and ending with the PCR result could be completed in eight hours. In conclusion, molecular methods using state-of-the-art assay techniques were developed for food safety testing. The combination of time-resolved fluorescence detection and ready-to-use reagents enabled sensitive assays easily amenable to automation. Consequently, together with the simplified sample preparation, these methods could prove to be applicable in routine testing.

Testing the FTPL across government tiers

Control on regional government budgets is important in a monetary union as lower tiers of government have fewer incentives to consolidate debt. According to the Fiscal Theory of the Price Level; unsustainable non-Ricardian fiscal policies eventually force monetary policy to adjust. Hence, uncoordinated and non-regulated regional fiscal policies would therefore threaten price stability for the monetary union as a whole. However, the union central bank is not without defense. A federal government that internalises the spillover effect of non-Ricardian fiscal policies on the price level can offset non-Ricardian regional fiscal policies. A federal government, which taxes and transfers resources between regions, may compensate for unsustainable regional fiscal policies so as to keep fiscal policy Ricardian on aggregate. Following Canzoneri et al. (2001), we test the validity of the Fiscal Theory of the Price Level for both federal and regional governments in Germany. We find evidence of a spillover effect of unsustainable policies on the price level for other Länder. However, the German federal government offsets this effect on the price level by running Ricardian policies. These results have implications for the regulation of fiscal policies in the EMU.

A Markov chain analysis of emotional exchange in voice-to-voice communication: Testing for the mimicry hypothesis of emotional contagion

Mimicry is a central plank of the emotional contagion theory; however, it was only tested with facial and postural emotional stimuli. This study explores the existence of mimicry in voice-to-voice communication by analyzing 8,747 sequences of emotional displays between customers and employees in a call-center context. We listened live to 967 telephone inter-actions, registered the sequences of emotional displays, and analyzed them with a Markov chain. We also explored other propositions of emotional contagion theory that were yet to be tested in vocal contexts. Results supported that mimicry is significantly present at all levels. Our findings fill an important gap in the emotional contagion theory; have practical implications regarding voice-to-voice interactions; and open doors for future vocal mimicry research.