Rewarding civil service performance through team bonuses : findings, analysis and recommendations

Performance-related pay within public organizations is continuing to spread. Although it can help to strengthen an entrepreneurial spirit in civil servants, its implementation is marred by technical, financial, managerial and cultural problems. This article identifies an added problem, namely the contradiction that exists between a managerial discourse that emphasizes the team and collective performance, on the one hand, and the use of appraisal and reward tools that are above all individual, on the other. Based on an empirical survey carried out within Swiss public organizations, the analysis shows that the team is currently rarely taken into account and singles out the principal routes towards an integrated system for the management and rewarding of civil servants.

A comparison of the performance of modern screen-film and digital mammography systems.

This work compares the detector performance and image quality of the new Kodak Min-R EV mammography screen-film system with the Fuji CR Profect detector and with other current mammography screen-film systems from Agfa, Fuji and Kodak. Basic image quality parameters (MTF, NPS, NEQ and DQE) were evaluated for a 28 kV Mo/Mo (HVL = 0.646 mm Al) beam using different mAs exposure settings. Compared with other screen-film systems, the new Kodak Min-R EV detector has the highest contrast and a low intrinsic noise level, giving better NEQ and DQE results, especially at high optical density. Thus, the properties of the new mammography film approach those of a fine mammography detector, especially at low frequency range. Screen-film systems provide the best resolution. The presampling MTF of the digital detector has a value of 15% at the Nyquist frequency and, due to the spread size of the laser beam, the use of a smaller pixel size would not permit a significant improvement of the detector resolution. The dual collection reading technology increases significantly the low frequency DQE of the Fuji CR system that can at present compete with the most efficient mammography screen-film systems.

Firm's network capability and innovation performance: evidences from China hi-tech industry

ABSTRACT : A firm's competitive advantage can arise from internal resources as well as from an interfirm network. -This dissertation investigates the competitive advantage of a firm involved in an innovation network by integrating strategic management theory and social network theory. It develops theory and provides empirical evidence that illustrates how a networked firm enables the network value and appropriates this value in an optimal way according to its strategic purpose. The four inter-related essays in this dissertation provide a framework that sheds light on the extraction of value from an innovation network by managing and designing the network in a proactive manner. The first essay reviews research in social network theory and knowledge transfer management, and identifies the crucial factors of innovation network configuration for a firm's learning performance or innovation output. The findings suggest that network structure, network relationship, and network position all impact on a firm's performance. Although the previous literature indicates that there are disagreements about the impact of dense or spare structure, as well as strong or weak ties, case evidence from Chinese software companies reveals that dense and strong connections with partners are positively associated with firms' performance. The second essay is a theoretical essay that illustrates the limitations of social network theory for explaining the source of network value and offers a new theoretical model that applies resource-based view to network environments. It suggests that network configurations, such as network structure, network relationship and network position, can be considered important network resources. In addition, this essay introduces the concept of network capability, and suggests that four types of network capabilities play an important role in unlocking the potential value of network resources and determining the distribution of network rents between partners. This essay also highlights the contingent effects of network capability on a firm's innovation output, and explains how the different impacts of network capability depend on a firm's strategic choices. This new theoretical model has been pre-tested with a case study of China software industry, which enhances the internal validity of this theory. The third essay addresses the questions of what impact network capability has on firm innovation performance and what are the antecedent factors of network capability. This essay employs a structural equation modelling methodology that uses a sample of 211 Chinese Hi-tech firms. It develops a measurement of network capability and reveals that networked firms deal with cooperation between, and coordination with partners on different levels according to their levels of network capability. The empirical results also suggests that IT maturity, the openness of culture, management system involved, and experience with network activities are antecedents of network capabilities. Furthermore, the two-group analysis of the role of international partner(s) shows that when there is a culture and norm gap between foreign partners, a firm must mobilize more resources and effort to improve its performance with respect to its innovation network. The fourth essay addresses the way in which network capabilities influence firm innovation performance. By using hierarchical multiple regression with data from Chinese Hi-tech firms, the findings suggest that there is a significant partial mediating effect of knowledge transfer on the relationships between network capabilities and innovation performance. The findings also reveal that the impacts of network capabilities divert with the environment and strategic decision the firm has made: exploration or exploitation. Network constructing capability provides a greater positive impact on and yields more contributions to innovation performance than does network operating capability in an exploration network. Network operating capability is more important than network constructing capability for innovative firms in an exploitation network. Therefore, these findings highlight that the firm can shape the innovation network proactively for better benefits, but when it does so, it should adjust its focus and change its efforts in accordance with its innovation purposes or strategic orientation.

Music Performance Anxiety (MPA) : cardiorespiratory activity in high- and low-anxious professional music students before a performance situation

Descriptors: music performance anxiety, respiration, hyperventilation Surveys indicate that high-anxious musicians may suffer from hyperventilation (HV) before or during performance. Reported symptoms include shortness of breath, fast/ deep breathing and thumping heart. However, no study has yet tested if these selfreported symptoms reflect actual cardiorespiratory activity. Themain goal of this study was to determine if MPA is manifested physiologically in specific correlates of cardiorespiratory activity associated with HV.We studied 74 professional music students from Swiss Music Academies. In this study, we compared the most anxious students (highanxious; n 5 20) with the least anxious students (low-anxious; n 5 23) based on their self-reported performance anxiety. We measured cardiorespiratory patterns with the Lifeshirt system, end-tidal CO2 with a capnograph (EtCO2, a good non-invasive estimator of HV), self-perceived physiological activation and affective experience in three situations on different days: baseline, performance without audience, and performance with audience. Comparing measures for the private vs. the public concert, high- compared to low-anxious students showed a significant drop in EtCO2 before the public concert and reported larger increases in anxiety, tension, palpitations and breathing difficulties. In contrast, heart rate, respiratory rate and volume did not differ significantly between groups. The results of this study support the hypothesis thatMPA may be associated with a tendency to hyperventilate and, thus, point to a potential hyperventilation problem in high-anxious music students.

Use of the Cognitive Performance Scale (CPS) to detect cognitive impairment in the acute care setting: concurrent and predictive validity.

The Cognitive Performance Scale (CPS) was initially designed to assess cognition in long term care residents. Subsequently, the CPS has also been used among in-home, post-acute, and acute care populations even though CPS' clinimetric performance has not been studied in these settings. This study aimed to determine CPS agreement with the Mini Mental Status Exam (MMSE) and its predictive validity for institutionalization and death in a cohort (N=401) of elderly medical inpatients aged 75 years and over. Medical, physical and mental status were assessed upon admission. The same day, the patient's nurse completed the CPS by interview. Follow-up data were gathered from the central billing system (nursing home stay) and proxies (death). Cognitive impairment was present in 92 (23%) patients according to CPS (score >or= 2). Agreement with MMSE was moderate (kappa 0.52, P<.001). Analysis of discordant results suggested that cognitive impairment was overestimated by the CPS in dependent patients with comorbidities and depressive symptoms, and underestimated in older ones. During follow-up, subjects with abnormal CPS had increased risks of death (adjusted hazard ratio (adjHR) 1.7, 95% CI 1.0-2.8, P=.035) and institutionalization (adjHR 2.7, 95% CI 1.3-5.3, P=.006), independent of demographic, health and functional status. Interestingly, subjects with abnormal CPS were at increased risk of death only if they also had abnormal MMSE. The CPS predicted death and institutionalization during follow-up, but correlated moderately well with the MMSE. Combining CPS and MMSE provided additional predictive information, suggesting that domains other than cognition are assessed by professionals when using the CPS in elderly medical inpatients.

Intraneuronal angiotensinergic system in rat and human dorsal root ganglia.

To elucidate the local formation of angiotensin II (Ang II) in the neurons of sensory dorsal root ganglia (DRG), we studied the expression of angiotensinogen (Ang-N)-, renin-, angiotensin converting enzyme (ACE)- and cathepsin D-mRNA, and the presence of protein renin, Ang II, Substance P and calcitonin gene-related peptide (CGRP) in the rat and human thoracic DRG. Quantitative real time PCR (qRT-PCR) studies revealed that rat DRG expressed substantial amounts of Ang-N- and ACE mRNA, while renin mRNA as well as the protein renin were untraceable. Cathepsin D-mRNA and cathepsin D-protein were detected in the rat DRG indicating the possibility of existence of pathways alternative to renin for Ang I formation. Angiotensin peptides were successfully detected with high performance liquid chromatography and radioimmunoassay in human DRG extracts. In situ hybridization in rat DRG confirmed additionally expression of Ang-N mRNA in the cytoplasm of numerous neurons. Intracellular Ang II staining could be shown in number of neurons and their processes in both the rat and human DRG. Interestingly we observed neuronal processes with angiotensinergic synapses en passant, colocalized with synaptophysin, within the DRG. In the DRG, we also identified by qRT-PCR, expression of Ang II receptor AT(1A) and AT(2)-mRNA while AT(1B)-mRNA was not traceable. In some neurons Substance P and CGRP were found colocalized with Ang II. The intracellular localization and colocalization of Ang II with Substance P and CGRP in the DRG neurons may indicate a participation and function of Ang II in the regulation of nociception. In conclusion, these results suggest that Ang II may be produced locally in the neurons of rat and human DRG and act as a neurotransmitter.

MOLECULAR MECHANISMS OF A ROOT SYSTEM TO SOIL ADAPTATION

Contrairement aux animaux, les plantes sont des organismes sessiles qui ne possèdent pas de mécanismes de fuite quand les conditions environnementales ne sont plus optimales. Les plantes sont physiquement ancrées à l'endroit où elles ont germées et aux conditions environnementales qui parfois peuvent être extrêmes. Les possibilités d'acclimatation de différentes espèces, parfois même de groupes de plantes au sein d'une même espèce, peuvent varier mais repose sur une adaptation génétique de la plante. L'adaptation est un long processus qui repose sur l'apparition spontanée de mutations génétiques, leur mise à l'épreuve face aux conditions environnementales, et dans le cas où la mutation a un impact positif sur la survie dans cet habitat particulier, elle sera maintenue dans une population donnée de plantes. De telles populations, appelées écotypes, sont le matériel de départ pour la découverte de gènes qui induisent un bénéfice pour la plante dans un environnement donné. La plante la plus étudiée en biologie moléculaire est Arabidopsis thaliana, l'arabette des prés. Dans une étude précédente, les racines d'écotypes naturels d'Arabidopsis ont été comparées et un écotype, Uk-1, avait le système racinaire le plus particulier. Cet écotype possède des racines beaucoup plus courtes et plus ramifiées que tous les autres écotypes. Des analyses plus poussées ont montré qu'une seule mutation dans un gène était la cause de ce phénotype, le gène BREVIS RADIX (BRX), mot latin signifiant 'racine courte'. Bien que l'on connaisse le gène BRX, on connaît finalement peu de choses sur son importance adaptative. Dans cette étude, nous avons montré que la mutation dans le gène BRX rend la plante plus résistante aux sols acides. Dans l'optique de mieux comprendre cette valeur adaptative du mutant brx, nous avons analysé dans quels tissus le gène BRX jouait un rôle important. Nous avons pu mettre en évidence que BRX est important pour le développement du protophloème. Le protophloème est un élément du système vasculaire de la plante. En général, les plantes supérieures possèdent deux systèmes de transport à longue distance. L'un d'eux, appelé xylème, transporte l'eau et les nutriments absorbés du sol par les racines vers les feuilles. Les feuilles sont le siège du processus de photosynthèse au cours duquel sont produits des sucres qui devront être distribués partout dans les autres parties de la plante. Le tissu cellulaire chargé de livrer les produits de la photosynthèse, ainsi que les régulateurs de croissance, est le phloème. Ce dernier regroupe le métaphloème et le protophloème. Le protophloème est essentiel pour la livraison des sucres synthétisés ainsi que des signaux de croissance aux pointes des racines, centres organogéniques responsables de la production de nouvelles cellules durant la phase de croissance de la racine. La structure du protophloème peut être décrite comme des tubes continus, vides et résistants, faits de cellules spécialisées qui permettent un transport efficace et rapide. Nous avons montré que dans les mutants brx ces canaux de transports sont discontinus car certaines cellules n'ont pas terminé leur cycle de différenciation. Ces cellules obstruent le conduit ce qui fait que les sucres et les signaux de croissance, comme l'auxine, ne peuvent plus être transportés aux méristèmes. En conséquence, la prolifération de l'activité des méristèmes est compromise, ce qui explique les racines courtes. Au lieu d'être délivré aux méristèmes, l'auxine se concentre en amont des méristèmes où cela provoque l'apparition de nouvelles racines branchées et, très probablement, l'activation des pompes à protons. Sur des sols acides, la concentration en ion H+ est très élevée. Ces ions entrent dans les cellules de la racine par diffusion et perturbent notablement la croissance des racines et de la plante en général. Si les cellules de la racine possédaient des pompes à protons hyperactives, elles seraient capable d'évacuer le surplus d'ions H+ en dehors de la cellule, ce qui leur assurerait de meilleures chances de survie sur sols acides. De fait, le mutant brx est capable d'acidifier le milieu de culture dans lequel il est cultivé plus efficacement que la plante sauvage. Ce mutant est également capable de donner plus de progéniture sur ce type de milieu de croissance que les plantes sauvages. Finalement, nous avons trouvé d'autres mutants brx en milieu naturel poussant sur sols acides, ce qui suggère fortement que la mutation du gène BRX est une des causes de l'adaptation aux sols acides. -- Plants as sessile organisms have developed different mechanisms to cope with the complex environmental conditions in which they live. Adaptation is the process through which traits evolve by natural selection to functionally improve in a given environmental context. An adaptation to the environment is characterized by the genetic changes in the entire populations that have been fixed by natural selection over many generations. BREVIS RADIX (BRX) gene was found through natural Arabidopsis accessions screen and was characterized as a root growth regulator since loss-of-function mutants exhibit arrested post-embryonic primary root growth in addition to a more branched root system. Although brx loss-of-function causes a complete alteration in root architecture, BRX activity is only required in the root vasculature, in particular in protophloem cell file. Protophloem is a part of the phloem transport network and is responsible for delivery of photo-assimilates and growth regulators, coming from the shoot through mature phloem component - metaphloem, to the all plant primary meristems. In order to perform its function, protophloem is the first cell file to differentiate within the root meristem. During this process, protophloem cells undergo a partial programmed cell death, during which they build a thicker cell wall, degrade nucleus and tonoplast while plasma membrane stays functional. Interestingly, protophloem cells enter elongation process only after differentiation into sieve elements is completed. Here we show that brx mutants fail to differentiate protophloem cell file properly, a phenotype that can be distinguished by a presence of a "gap" cells, non-differentiated cells between two flanking differentiated cells. Discontinuity of protophloem differentiation in brx mutants is considered to be a consequence of local hyperactivity of CLAVATA3/EMBRYO SURROUNDING REGION 45 (CLE45) - BARELY ANY MERISTEM 3 (BAM3) signaling module. Interestingly, a CLE45 activity, most probably at the level of receptor binding, can be modulated by apoplastic pH. Altogether, our results imply that the activity of proton pumps, expressed in non-differentiated cells of protophloem, must be maintained under certain threshold, otherwise CLE45-BAM3 signaling pathway will be stimulated and in turn protophloem will not differentiate. Based on vacuolar morphology, a premature cell wall acidification in brx mutants stochastically prevents the protophloem differentiation. Only after protophloem differentiates, proton pumps can be activated in order to acidify apoplast and to support enucleated protophloem multifold elongation driven by surrounding cells growth. Finally, the protophloem differentiation failure would result in an auxin "traffic jam" in the upper parts of the root, created from the phloem-transported auxin that cannot be efficiently delivered to the meristem. Physiologically, auxin "leakage" from the plant vasculature network could have various consequences, since auxin is involved in the regulation of almost every aspect of plant growth and development. Thus, given that auxin stimulates lateral roots initiation and growth, this scenario explains more branched brx root system. Nevertheless, auxin is considered to activate plasma membrane proton pumps. Along with this, it has been shown that brx mutants acidify media much more than the wild type plants do, a trait that was proposed as an adaptive feature of naturally occurring brx null alleles in Arabidopsis populations found on acidic soils. Additionally, in our study we found that most of accessions originally collected from acidic sampling sites exhibit hypersensitivity to CLE45 treatment. This implies that adaptation of plants to acidic soil involves a positive selection pressure against upstream negative regulators of CLE45-BAM3 signaling, such as BRX. Perspective analysis of these accessions would provide more profound understanding of molecular mechanisms underlying plant adaptation to acidic soils. All these results are suggesting that targeting of the factors that affect protophloem differentiation is a good strategy of natural selection to change the root architecture and to develop an adaptation to a certain environment. -- Les plantes comme organismes sessiles ont développé différents mécanismes pour s'adapter aux conditions environnementales complexes dans lesquelles elles vivent. L'adaptation est le processus par lequel des traits vont évoluer via la sélection naturelle vers une amélioration fonctionnelle dans un contexte environnemental donné. Une adaptation à l'environnement est caractérisée par des changements génétiques dans des populations entières qui ont été fixés par la sélection naturelle sur plusieurs générations. Le gène BREVIS RADIX (BRX) a été identifié dans le crible d'une collection d'accessions naturelles d'Arabidopsis et a été caractérisé comme un régulateur de la croissance racinaire étant donné que le mutant perte-de-fonction montre une croissance racinaire primaire arrêtée au stade post-embryonnaire et présente de plus un système racinaire plus ramifié que la plante sauvage. Bien que le mutant perte-de-fonction brx cause une altération complète de l'architecture racinaire, l'activité de BRX n'est requise que dans la vascularisation racinaire, en particulier au niveau du protophloème. Le protophloème est un composant du réseau de transport du phloème et est responsable du transit des dérivés de la photosynthèse ainsi que des régulateurs de croissances, venant de la partie aérienne par le phloème mature (métaphloème) vers tous les méristèmes primaires de la plante. Pour pouvoir réaliser sa fonction, le protophloème est la première file de cellules à se différencier à l'intérieur du méristème de la racine. Pendant ce processus, les cellules du protophloème subissent une mort cellulaire programmée partielle durant laquelle elles épaississent leur paroi cellulaire, dégradent le noyau et le tonoplaste tandis que la membrane plasmique demeure fonctionnelle. De manière intéressante, les cellules du protophloème entament le processus d'allongement seulement après que la différenciation en tubes criblés soit complète. Ce travail montre que le mutant brx est incapable de mener à bien la différenciation de la file de cellules du protophloème, phénotype qui peut être visualisé par la présence de cellules 'trous', de cellules non différenciées entourées de deux cellules différenciées. La discontinuité de la différenciation du phloème dans le mutant brx est considérée comme la conséquence de l'hyperactivité localisée du module de signalisation CLA VA TA3/EMBRYO SURROUNDING REGION 45 (CLE45) - BARELY ANY MERISTEM 3 (BAM3). De manière intéressante, l'activité de CLE45, très probablement au niveau de la liaison avec le récepteur, peut être modulé par le pH apoplastique. Pris ensemble, nos résultats impliquent que l'activité des pompes à protons, actives dans les cellules non différenciées du protophloème, doit être maintenue en dessous d'un certain seuil autrement la cascade de signalisation CLE45-BAM3 serait stimulée, en conséquence de quoi le protophloème ne pourrait se différencier. D'après la morphologie vacuolaire, une acidification prématurée de la paroi cellulaire dans le mutant brx empêche la différenciation du protophloème de manière stochastique. Une fois que le protophloème se différencie, les pompes à protons peuvent alors être activées afin d'acidifier l'apoplaste et ainsi faciliter l'allongement des cellules énuclées du protophloème, entraînées par la croissance des cellules environnantes. Finalement, la différenciation défectueuse du protophloème produit une accumulation d'auxine dans la partie supérieure de la racine car le phloème ne peut plus acheminer efficacement l'auxine au méristème. Physiologiquement, la 'fuite' d'auxine à partir du réseau vasculaire de la plante peut avoir des conséquences variées puisque l'auxine est impliquée dans la régulation de la majorité des aspects de la croissance et développement de la plante. Etant donné que l'auxine stimule l'initiation et développement des racines latérales, ce scénario pourrait expliquer le système racinaire plus ramifié du mutant brx. En plus, l'auxine est considérée comme un activateur des pompes à protons. Par ailleurs, nous avons montré que les mutants brx ont la capacité d'acidifier le milieu plus efficacement que les plantes sauvages, une caractéristique des populations sauvages <¥Arabidopsis poussant sur des sols acides et contenant les allèles délétés brx. De plus, dans nos résultats nous avons mis en évidence que la plupart des accessions collectées originellement sur des sites acidophiles montre une hypersensibilité au traitement par CLE45. Ceci implique que l'adaptation des plantes aux sols acides repose sur la pression de sélection positive à rencontre des régulateurs négatifs de CLE45- BAM3, situés en amont de la cascade, tel le produit du gène BRX. Les analyses de ces accessions pourraient aboutir à une meilleure compréhension des mécanismes moléculaires responsables de l'adaptation des plantes aux sols acides. Tous nos résultats suggèrent que le ciblage des facteurs affectant la différenciation du protophloème serait une stratégie gagnante dans la sélection naturelle pour changer l'architecture de la racine et ainsi s'adapter efficacement à un nouvel environnement.

A new ambulatory system for comparative evaluation of the three-dimensional knee kinematics, applied to anterior cruciate ligament injuries

The aim of this study was to develop an ambulatory system for the three-dimensional (3D) knee kinematics evaluation, which can be used outside a laboratory during long-term monitoring. In order to show the efficacy of this ambulatory system, knee function was analysed using this system, after an anterior cruciate ligament (ACL) lesion, and after reconstructive surgery. The proposed system was composed of two 3D gyroscopes, fixed on the shank and on the thigh, and a portable data logger for signal recording. The measured parameters were the 3D mean range of motion (ROM) and the healthy knee was used as control. The precision of this system was first assessed using an ultrasound reference system. The repeatability was also estimated. A clinical study was then performed on five unilateral ACL-deficient men (range: 19-36 years) prior to, and a year after the surgery. The patients were evaluated with the IKDC score and the kinematics measurements were carried out on a 30 m walking trial. The precision in comparison with the reference system was 4.4 degrees , 2.7 degrees and 4.2 degrees for flexion-extension, internal-external rotation, and abduction-adduction, respectively. The repeatability of the results for the three directions was 0.8 degrees , 0.7 degrees and 1.8 degrees . The averaged ROM of the five patients' healthy knee were 70.1 degrees (standard deviation (SD) 5.8 degrees), 24.0 degrees (SD 3.0 degrees) and 12.0 degrees (SD 6.3 degrees for flexion-extension, internal-external rotation and abduction-adduction before surgery, and 76.5 degrees (SD 4.1 degrees), 21.7 degrees (SD 4.9 degrees) and 10.2 degrees (SD 4.6 degrees) 1 year following the reconstruction. The results for the pathologic knee were 64.5 degrees (SD 6.9 degrees), 20.6 degrees (SD 4.0 degrees) and 19.7 degrees (8.2 degrees) during the first evaluation, and 72.3 degrees (SD 2.4 degrees), 25.8 degrees (SD 6.4 degrees) and 12.4 degrees (SD 2.3 degrees) during the second one. The performance of the system enabled us to detect knee function modifications in the sagittal and transverse plane. Prior to the reconstruction, the ROM of the injured knee was lower in flexion-extension and internal-external rotation in comparison with the controlateral knee. One year after the surgery, four patients were classified normal (A) and one almost normal (B), according to the IKDC score, and changes in the kinematics of the five patients remained: lower flexion-extension ROM and higher internal-external rotation ROM in comparison with the controlateral knee. The 3D kinematics was changed after an ACL lesion and remained altered one year after the surgery

A comparison of the imaging characteristics of the new Kodak Hyper Speed G film with the current T-MAT G/RA film and the CR 9000 system.

Three standard radiation qualities (RQA 3, RQA 5 and RQA 9) and two screens, Kodak Lanex Regular and Insight Skeletal, were used to compare the imaging performance and dose requirements of the new Kodak Hyper Speed G and the current Kodak T-MAT G/RA medical x-ray films. The noise equivalent quanta (NEQ) and detective quantum efficiencies (DQE) of the four screen-film combinations were measured at three gross optical densities and compared with the characteristics for the Kodak CR 9000 system with GP (general purpose) and HR (high resolution) phosphor plates. The new Hyper Speed G film has double the intrinsic sensitivity of the T-MAT G/RA film and a higher contrast in the high optical density range for comparable exposure latitude. By providing both high sensitivity and high spatial resolution, the new film significantly improves the compromise between dose and image quality. As expected, the new film has a higher noise level and a lower signal-to-noise ratio than the standard film, although in the high frequency range this is compensated for by a better resolution, giving better DQE results--especially at high optical density. Both screen-film systems outperform the phosphor plates in terms of MTF and DQE for standard imaging conditions (Regular screen at RQA 5 and RQA 9 beam qualities). At low energy (RQA 3), the CR system has a comparable low-frequency DQE to screen-film systems when used with a fine screen at low and middle optical densities, and a superior low-frequency DQE at high optical density.

A wearable system to time gate crossing during alpine skiing slalom

INTRODUCTION: In alpine skiing, chronometry analysis is currently the most common tool to assess performance. It is widely used to rank competitors during races, as well as to manage athletes training and to evaluate material. Usually, this measurement is accurately realized using timing cells. Nevertheless, these devices are too complex and expensive to allow chronometry of every gates crossing. On the other side, differential GPS can be used for measuring gate crossing time (Waegli et al). However, this is complex (e.g. recording gate position with GPS) and mainly used in research applications. The aim of the study was to propose a wearable system to time gates crossing during alpine skiing slalom (SL), which is suitable for routine uses. METHODS: The proposed system was composed of a 3D accelerometer (ADXL320®, Analog Device, USA) placed at the sacrum of the athlete, a matrix of force sensors (Flexiforce®, Tekscan, USA) fixed on the right shin guard and a data logger (Physilog®, BioAGM, Switzerland). The sensors were sampled at 500 Hz. The crossing time were calculated in two phases. First, the accelerometer was used to detect the curves by considering the maximum of the mediolateral peak acceleration. Then, the force sensors were used to detect the impacts with the gates by considering maximum force variation. In case of non impact, the detection was realized based on the acceleration and features measured at the other gates. In order to assess the efficiency of the system, two different SL were monitored twice for two world cup level skiers, a male SL expert and a female downhill expert. RESULTS AND DISCUSSION: The combination of the accelerometer and force sensors allowed to clearly identify the gate crossing times. When comparing the runs of the SL expert and the downhill expert, we noticed that the SL expert was faster. For example for the first SL, the overall difference between the best run of each athlete was of 5.47s. At each gate, the SL expert increased the time difference slower at the beginning (0.27s/gate) than at the end (0.34s/gate). Furthermore, when comparing the runs of the SL expert, a maximum time difference of 20ms at each gate was noticed. This showed high repeatability skills of the SL expert. In opposite, the downhill expert with a maximum difference time of 1s at each gate was clearly less repeatable. Both skiers were not disturbed by the system. CONCLUSION: This study proposed a new wearable system to automatically time gates crossing during alpine skiing slalom combining force and accelerometer sensors. The system was evaluated with two professional world cup skiers and showed a high potential. This system could be extended to time other parameters. REFERENCES Waegli A, Skaloud J (2007). Inside GNSS, Spring, 24-34.

Evaluation of a piezoelectric system as an alternative to electroencephalogram/ electromyogram recordings in mouse sleep studies.

STUDY OBJECTIVES: Traditionally, sleep studies in mammals are performed using electroencephalogram/electromyogram (EEG/EMG) recordings to determine sleep-wake state. In laboratory animals, this requires surgery and recovery time and causes discomfort to the animal. In this study, we evaluated the performance of an alternative, noninvasive approach utilizing piezoelectric films to determine sleep and wakefulness in mice by simultaneous EEG/EMG recordings. The piezoelectric films detect the animal's movements with high sensitivity and the regularity of the piezo output signal, related to the regular breathing movements characteristic of sleep, serves to automatically determine sleep. Although the system is commercially available (Signal Solutions LLC, Lexington, KY), this is the first statistical validation of various aspects of sleep. DESIGN: EEG/EMG and piezo signals were recorded simultaneously during 48 h. SETTING: Mouse sleep laboratory. PARTICIPANTS: Nine male and nine female CFW outbred mice. INTERVENTIONS: EEG/EMG surgery. MEASUREMENTS AND RESULTS: The results showed a high correspondence between EEG/EMG-determined and piezo-determined total sleep time and the distribution of sleep over a 48-h baseline recording with 18 mice. Moreover, the piezo system was capable of assessing sleep quality (i.e., sleep consolidation) and interesting observations at transitions to and from rapid eye movement sleep were made that could be exploited in the future to also distinguish the two sleep states. CONCLUSIONS: The piezo system proved to be a reliable alternative to electroencephalogram/electromyogram recording in the mouse and will be useful for first-pass, large-scale sleep screens for genetic or pharmacological studies. CITATION: Mang GM, Nicod J, Emmenegger Y, Donohue KD, O'Hara BF, Franken P. Evaluation of a piezoelectric system as an alternative to electroencephalogram/electromyogram recordings in mouse sleep studies.

Variation in performance in low-volume mammography screening programmes: experience from Switzerland.

BACKGROUND: Reading volume and mammography screening performance appear positively correlated. Quality and effectiveness were compared across low-volume screening programmes targeting relatively small populations and operating under the same decentralised healthcare system. Except for accreditation of 2nd readers (restrictive vs non-restrictive strategy), these organised programmes had similar screening regimen/procedures and duration, which maximises comparability. Variation in performance and its determinants were explored in order to improve mammography practice and optimise screening performance. METHODS: Circa 200,000 screens performed between 1999 and 2006 (4 rounds) in 3 longest standing Swiss cantonal programmes (of Vaud, Geneva and Valais) were assessed. Indicators of quality and effectiveness were assessed according to European standards. Interval cancers were identified through linkage with cancer registries records. RESULTS: Swiss programmes met most European standards of performance with a substantial, favourable cancer stage shift. Up to a two-fold variation occurred for several performance indicators. In subsequent rounds, compared with programmes (Vaud and Geneva) that applied a restrictive selection strategy for 2nd readers, proportions of in situ lesions and of small cancers (≤1cm) were one third lower and halved, respectively, and the proportion of advanced lesions (stage II+) nearly 50% higher in the programme without a restrictive selection strategy. Discrepancy in second-year proportional incidence of interval cancers appears to be multicausal. CONCLUSION: Differences in performance could partly be explained by a selective strategy for second readers and a prior experience in service screening, but not by the levels of opportunistic screening and programme attendance. This study provides clues for enhancing mammography screening performance in low-volume programmes.

Effect of water velocity on the uptake of polychlorinatedd biphenyls (PCBs) by silicone rubber (SR) and low-density polyethylene (LDPE) passive samplers: an assessment of the efficiency of performance reference compounds (PRCs) in river-like flow conditions

One aim of this study is to determine the impact of water velocity on the uptake of indicator polychlorinated biphenyls (iPCBs) by silicone rubber (SR) and low-density polyethylene (LDPE) passive samplers. A second aim is to assess the efficiency of performance reference compounds (PRCs) to correct for the impact of water velocity. SR and LDPE samplers were spiked with 11 or 12 PRCs and exposed for 6 weeks to four different velocities (in the range of 1.6 to 37.7 cm s−1) in river-like flow conditions using a channel system supplied with river water. A relationship between velocity and the uptakewas found for each iPCB and enables to determine expected changes in the uptake due to velocity variations. For both samplers, velocity increases from 2 to 10 cm s−1, 30 cm s−1 (interpolated data) and 100 cm s−1 (extrapolated data) lead to increases of the uptake which do not exceed a factor of 2, 3 and 4.5, respectively. Results also showed that the influence of velocity decreased with increasing the octanol-water coefficient partition (log Kow) of iPCBs when SR is used whereas the opposite effect was observed for LDPE. Time-weighted average (TWA) concentrations of iPCBs in water were calculated from iPCB uptake and PRC release. These calculations were performed using either a single PRC or all the PRCs. The efficiency of PRCs to correct the impact of velocity was assessed by comparing the TWA concentrations obtained at the four tested velocities. For SR, a good agreement was found among the four TWA concentrations with both methods (average RSD b 10%). Also for LDPE, PRCs offered a good correction of the impact of water velocity (average RSD of about 10 to 20%). These results contribute to the process of acceptance of passive sampling in routine regulatory monitoring programs.