bluuebunny/crossref_metadata_2025 huggingface dataset:
Understanding of the chopping frequency effect on IPCE measurements for dye-sensitized solar cells: from the viewpoint of electron transport and extinction spectrum
Authors: Xue Guogang , Yu Xirui , Yu Tao , Bao Chunxiong , Zhang Jiyuan , Guan Jie , Huang Huan , Tang Zekun , Zou Zhigang
Published: October 2012

The incident monochromatic photon to electron conversion efficiency (IPCE) is an essential characterization method for the photoelectrical performance of solar cells. An IPCE measurement apparatus involving alternating current (ac) and direct current (dc) methods was set up. A chopping frequency effect on IPCE measurements was found for dye-sensitized solar cells (DSSCs), that is, with the increase in chopping frequency, the IPCE spectrum decreased significantly, and the different bands of the IPCE spectrum declined to different degrees. The chopping frequency effect was studied in detail by measuring the short-circuit current waveform, the extinction spectrum of the dye-coated TiO2 photoelectrode film and electrochemical impedance spectroscopy. The mechanism of the chopping frequency effect was investigated from the electron transport and extinction spectrum. The electron transport properties of the TiO2 photoelectrode film determined the slow response of DSSCs. From the extinction spectrum, the transport distance of electrons in the TiO2 film varied under the illumination of different monochromatic light. For DSSCs, the ac method was remarkably influenced by the trap states of electrons and the optical penetration depth, while the dc method was a steady-state measurement avoiding the impact of these two factors. Thus, the dc method is more suitable than the ac method for IPCE measurements of DSSCs.
Bipolar and unipolar resistive switching effects in Al/DLC/W structure
Authors: Peng Pinggang , Xie Dan , Yang Yi , Zhou Changjian , Ma Shuo , Feng Tingting , Tian He , Ren Tianling
Published: October 2012

The full text of this corrigendum is available in the PDF.
Numerical simulation of current evolution in the Compact Toroidal Hybrid
Authors: Schlutt M.G. , Hegna C.C. , Sovinec C.R. , Knowlton S.F. , Hebert J.D.
Published: October 2012

Nonlinear magnetohydrodynamic computation is applied to study magnetic topology evolution for current-driven discharges in the Compact Toroidal Hybrid (CTH). In these simulations, ohmic currents are driven with a constant applied loop voltage in zero-beta plasmas. These driven currents initially are aligned with the vacuum flux surfaces. The rotational transform increases with rising plasma current, exhibiting a broad profile during the current rise. Island structures appear as low-order rational surfaces come into resonance. Because CTH is a five field period device, island structures have a toroidal periodicity of n = 5. There is special significance when the rotational transform exceeds 1/2. At this point m/n = 10/5 island chains appear that subsequently evolve to m/n = 2/1 islands through a coalescence process. With more driven current, a region of magnetic stochasticity grows that ultimately destroys flux surfaces. UW-CPTC Report 12-5.
Pathogen Variation and Urea Influence Selection and Success of Streptomyces Mixtures in Biological Control
Authors: Otto-Hanson L. K. , Grabau Z. , Rosen C. , Salomon C. E. , Kinkel L. L.
Published: October 2012

Success in biological control of plant diseases remains inconsistent in the field. A collection of well-characterized Streptomyces antagonists (n = 19 isolates) was tested for their capacities to inhibit pathogenic Streptomyces scabies (n = 15 isolates). There was significant variation among antagonists in ability to inhibit pathogen isolates and among pathogens in their susceptibility to inhibition. Only one antagonist could inhibit all pathogens, and antagonist–pathogen interactions were highly specific, highlighting the limitations of single-strain inoculum in biological control. However, the collection of pathogens could be inhibited by several combinations of antagonists, suggesting the potential for successful antagonist mixtures. Urea generally increased effectiveness of antagonists at inhibiting pathogens in vitro (increased mean inhibition zones) but its specific effects varied among antagonist–pathogen combinations. In greenhouse trials, urea enhanced the effectiveness of antagonist mixtures relative to individual antagonists in controlling potato scab. Although antagonist mixtures were frequently antagonistic in the absence of urea, all n= 2 and n = 3 antagonist–isolate combinations were synergistic in the presence of urea. This work provides insights into the efficacy of single- versus multiple-strain inocula in biological control and on the potential for nutrients to influence mixture success.
A mechanistic model for bromodeoxyuridine dilution naturally explains labelling data of self-renewing T cell populations
Authors: Ganusov Vitaly V. , De Boer Rob J.
Published: October 2012

Bromodeoxyuridine (BrdU) is widely used in immunology to detect cell division, and several mathematical models have been proposed to estimate proliferation and death rates of lymphocytes from BrdU labelling and de-labelling curves. One problem in interpreting BrdU data is explaining the de-labelling curves. Because shortly after label withdrawal, BrdU
+
cells are expected to divide into BrdU
+
daughter cells, one would expect a flat down-slope. As for many cell types, the fraction of BrdU
+
cells decreases during de-labelling, previous mathematical models had to make debatable assumptions to be able to account for the data. We develop a mechanistic model tracking the number of divisions that each cell has undergone in the presence and absence of BrdU, and allow cells to accumulate and dilute their BrdU content. From the same mechanistic model, one can naturally derive expressions for the mean BrdU content (MBC) of all cells, or the MBC of the BrdU
+
subset, which is related to the mean fluorescence intensity of BrdU that can be measured in experiments. The model is extended to include subpopulations with different rates of division and death (i.e. kinetic heterogeneity). We fit the extended model to previously published BrdU data from memory T lymphocytes in simian immunodeficiency virus-infected and uninfected macaques, and find that the model describes the data with at least the same quality as previous models. Because the same model predicts a modest decline in the MBC of BrdU
+
cells, which is consistent with experimental observations, BrdU dilution seems a natural explanation for the observed down-slopes in self-renewing populations.
Stochastic dynamics of snow avalanche occurrence by superposition of Poisson processes
Authors: Perona Paolo , Daly Edoardo , Crouzy Benoît , Porporato Amilcare
Published: October 2012

We study the dynamics of systems with deterministic trajectories randomly forced by instantaneous discontinuous jumps occurring according to two different compound Poisson processes. One process, with constant frequency, causes instantaneous positive random increments, whereas the second process has a state-dependent frequency and describes negative jumps that force the system to restart from zero (renewal jumps). We obtain the probability distributions of the state variable and the magnitude and intertimes of the jumps to zero. This modelling framework is used to describe snow-depth dynamics on mountain hillsides, where the positive jumps represent snowfall events, whereas the jumps to zero describe avalanches. The probability distributions of snow depth, together with the statistics of avalanche magnitude and occurrence, are used to explain the correlation between avalanche occurrence and snowfall as a function of hydrologic, terrain slope and aspect parameters. This information is synthesized into a ‘prediction entropy’ function that gives the level of confidence of avalanche occurrence prediction in relation to terrain properties.
Flow of a liquid layer over heated topography
Authors: Blyth M. G. , Bassom Andrew P.
Published: October 2012

The flow of a viscous liquid layer over an inclined uneven wall heated from below is considered. The flow is assumed to occur at zero Reynolds number and the thermal Péclet number is taken to be sufficiently small that the temperature field inside the layer is governed by Laplace’s equation. With a prescribed wall temperature distribution and Newton’s Law of cooling imposed at the layer surface, the emphasis is placed on describing the surface profile of the liquid layer and, in particular, on studying how this is affected by wall heating. A linearized theory, valid when the amplitude of the wall topography is small, is derived and this is complemented by some nonlinear results computed using the boundary element method. It is shown that for flow over a sinusoidally shaped wall the liquid layer can be completely flattened by differential wall heating. For flow over a flat wall with a downwards step, it is demonstrated how the capillary ridge that has been identified by previous workers may be eliminated by suitable localized wall cooling in the vicinity of the step.
The influence of male age and simulated pathogenic infection on producing a dishonest sexual signal
Authors: Copeland Emily K. , Fedorka Kenneth M.
Published: October 2012

In recent years, studies have shown that reproductive effort decelerates in response to pathogenic infection. If infection substantially reduces a host's residual reproductive value (RRV), however, then an acceleration of effort may instead occur (e.g. terminal investment). Reproductive acceleration would theoretically allow hosts to maintain or exaggerate their sexual signal upon infection. This would create a deceptive message from the perspective of the chooser, who may unwittingly copulate with an infected mate to their detriment. Using the cricket
Allonemobius socius
, we assessed the potential for reduced RRV to accelerate male reproductive effort and create a dishonest signal. RRV was manipulated through male age and simulated pathogenic insult. Reproductive effort was measured as calling song energetics, mating success, latency to mate and nuptial gift size. We show that males adopted either an accelerated or decelerated reproductive strategy upon infection, and that this decision was probably mediated by RRV. Moreover, males who accelerated their effort produced a dishonest signal by increasing their song energetics while providing fewer paternal resources (i.e. smaller gifts). Our study is one of the few to document the existence of dishonest signals and relate dishonesty to a potential reduction in female fitness, underscoring the conflict inherent in sexual reproduction.
Genome and transcriptome sequencing of lung cancers reveal diverse mutational and splicing events
Authors: Liu Jinfeng , Lee William , Jiang Zhaoshi , Chen Zhongqiang , Jhunjhunwala Suchit , Haverty Peter M. , Gnad Florian , Guan Yinghui , Gilbert Houston N. , Stinson Jeremy , Klijn Christiaan , Guillory Joseph , Bhatt Deepali , Vartanian Steffan , Walter Kimberly , Chan Jocelyn , Holcomb Thomas , Dijkgraaf Peter , Johnson Stephanie , Koeman Julie , Minna John D. , Gazdar Adi F. , Stern Howard M. , Hoeflich Klaus P. , Wu Thomas D. , Settleman Jeff , de Sauvage Frederic J. , Gentleman Robert C. , Neve Richard M. , Stokoe David , Modrusan Zora , Seshagiri Somasekar , Shames David S. , Zhang Zemin
Published: October 2012

Lung cancer is a highly heterogeneous disease in terms of both underlying genetic lesions and response to therapeutic treatments. We performed deep whole-genome sequencing and transcriptome sequencing on 19 lung cancer cell lines and three lung tumor/normal pairs. Overall, our data show that cell line models exhibit similar mutation spectra to human tumor samples. Smoker and never-smoker cancer samples exhibit distinguishable patterns of mutations. A number of epigenetic regulators, including KDM6A, ASH1L, SMARCA4, and ATAD2, are frequently altered by mutations or copy number changes. A systematic survey of splice-site mutations identified 106 splice site mutations associated with cancer specific aberrant splicing, including mutations in several known cancer-related genes. RAC1b, an isoform of the RAC1 GTPase that includes one additional exon, was found to be preferentially up-regulated in lung cancer. We further show that its expression is significantly associated with sensitivity to a MAP2K (MEK) inhibitor PD-0325901. Taken together, these data present a comprehensive genomic landscape of a large number of lung cancer samples and further demonstrate that cancer-specific alternative splicing is a widespread phenomenon that has potential utility as therapeutic biomarkers. The detailed characterizations of the lung cancer cell lines also provide genomic context to the vast amount of experimental data gathered for these lines over the decades, and represent highly valuable resources for cancer biology.
Making public management work in the global economy: lessons from Europe and North America
Authors: Roberge Ian , Jesuit David K.
Published: October 2012

Purpose

The purpose of this paper is to present the main themes in this special issue focusing on the impact of transformations in the global economy on public management.

Design/methodology/approach

This paper takes the from of a presentation of articles in this special issue.

Findings

The paper finds that focusing on examples form Europe and North America, public management adaptability varies across states and regions. Capacity is identified as an important indicator of adaptability.

Originality/value

The paper introduces an issue that highlights concrete examples of adaptability in public management. It opens the door to further research tracing linkages between changes in the global environment and the practice of public management.
Estimating the effect of racino restaurant sales on slot wagering volume
Authors: Kalargyrou Valentini , Singh A.K. , Lucas Anthony F.
Published: October 2012

Purpose

The purpose of this paper is to estimate the effects of onsite restaurant business volume on slot machine gaming volume at a Midwestern racino property. The results provide management with critical estimates for use in determining the overall value of the restaurant space. Additionally, operators are able to examine whether it makes sense to operate restaurants at a loss, based on the notion that the dining outlets are contributing to gaming volumes.

Design/methodology/approach

Time series multiple regression analysis is used to analyze daily performance data, providing an estimate of the change in the dollar amount of slot wagers resulting from a one‐unit increase in the dollar value of restaurant sales.

Findings

The theoretical model advanced herein explained 81 percent of the variation in the aggregate, daily dollar value of slot wagers. A one‐dollar increase in the variable representing overall restaurant sales produced a $91 increase in slot wagers (or $7.44 in slot win).

Research limitations/implications

Regression analysis does not prove cause and effect. The result was produced from a single data set. Operators are encouraged to examine their own data via the method and model advanced herein.

Practical implications

The results provide management an opportunity to examine whether the slot win associated with the restaurant operations exceeds the operating losses incurred by the restaurants, and, if so, by how much.

Originality/value

This is the first study to examine empirically the relationship between restaurant and gaming business volumes at a racino. Specifically, no published study includes statistically derived estimates of the impact of changes in on‐site restaurant volume on a racino's slot wagering volume.
Chinese employees' interpersonal conflict management strategies
Authors: Nguyen Hannah‐Hanh D. , Yang Jie
Published: October 2012

Purpose

The main research purposes of this paper are to: conceptualize Chinese conflict management behaviors as contingent on the hierarchical relations of conflict parties in an organizational context; and investigate individual characteristics as moderators in this contingency framework.

Design/methodology/approach

This emic study consisted of two steps: using nine subject matter experts to develop conflict scenarios and conflict management strategies, and using this instrument to collect data from 704 actual employees across China. Multinomial logistic analysis was used to analyze respondents' choice of strategies.

Findings

The findings supported the hypotheses. Chinese role‐playing a supervisor in a conflict with their subordinate tended to use direct, assertive strategies to resolve the conflict, but the results depended on age, education, gender, region and work experience. As a subordinate in a conflict with their supervisor, Chinese chose indirect, harmony‐preserving strategies, particularly when they were older and more interaction adept. In a conflict with a peer, respondents used a broader spectrum of conflict management strategies, depending on their individual characteristics. No “best practices” were found or universal strategies adopted.

Research limitations/implications

The limitations include the lack of random sampling and a scenario‐based method. The emic evidence for a contingency perspective of conflict resolution framework was provided. The conflict scenarios may be used in organizational training of conflict management.

Originality/value

Conflict scenarios and management strategies developed by local subject matter experts were used to evaluate Chinese workers' choices of conflict management strategies. The findings call for the re‐conceptualization of conflict management strategies as a contingent and culture‐specific construct.
Examining the role of identity in negotiation decision making:the case of Cyprus
Authors: Sirin Cigdem V.
Published: October 2012

Purpose

This study aims to examine the effects of ethnic and social identities on negotiation decision making in the context of the Cyprus conflict.

Design/methodology/approach

The author conducts a theory‐driven case study of the 1959 Zurich‐London agreements on Cyprus, analyzing the positions of Turkey, Greece, Britain, and the Turkish and Greek Cypriot communities during the negotiation process. The analytical method is the applied decision analysis procedure.

Findings

The analysis of the Zurich‐London negotiations over Cyprus suggests that even in the presence of adversarial ethnic ties, decision makers who have a shared (and salient) social identity are more likely to employ collective‐serving decision strategies and seek even‐handed solutions that will not jeopardize their mutual interests. Here, Turkey and Greece – both NATO members – decided to settle on a commonly agreed negotiation outcome despite their ethnicity‐driven, clashing interests over Cyprus. In contrast, decision makers with severe ethnic fragmentation with no shared social identity (as with the Turkish and Greek Cypriot communities) are more prone to employ self‐serving decision strategies and seek zero‐sum negotiation outcomes that will exclusively benefit them.

Research limitations/implications

Regarding the applied decision analysis procedure employed in this study, it is necessary to acknowledge the subjective nature of the construction of the decision matrices with respective values/ratings, even though such procedure is based on empirical and situational evidence.

Originality/value

The study introduces a novel theoretical and analytical framework to the literature on negotiation decision making in identity‐based conflicts by combining the social contextualist perspective with the polyheuristic decision model and using applied decision analysis. By anchoring the analysis in the historical context of the Cyprus conflict, the study also contributes to the relatively underdeveloped literature on conflict management in the Middle East.
Ireland's new Innovation Academy: academic‐practitioner partnerships in action
Authors: Jarvis Suzi , Mitchell Frances
Published: October 2012

Purpose

In November 2010 Ireland launched a new multi‐institutional academic initiative called The Innovation Academy to provide credited teaching programmes in innovation and entrepreneurial thinking to be taken in parallel with university doctoral programmes of any discipline. This article aims to examine the design and development of this new initiative, how it integrates external organizations into its teaching programmes and how this practically translates into employment and job creation.

Design/methodology/approach

The authors approached this paper using a standard qualitative data gathering approach, analyzing student reflection documents and enterprise partner feedback as well as quantitative data on participation from both academic and enterprise sources.

Findings

It was found that working with enterprises as part of the Innovation Academy Graduate Certificate in innovation and entrepreneurship has a significant impact on both the student and the enterprise partner. Students describe an increase in confidence, creativity and team‐working skills. Enterprise partners find that having student teams in their workplace reinvigorates their own staff.

Originality/value

The Innovation Academy is a new initiative in Ireland that promotes entrepreneurial thinking in postgraduate students. The structure of the course is designed to be broadly appealing so that it easily translates to an undergraduate and professional student base. The tight integration of industry (public, private and charitable) ensures that the programme consistently has its finger on the pulse of the current economic climate.
Creative management in TAMK Proacademy
Authors: Nevalainen Timo , Maijala Miia
Published: October 2012

Purpose

This paper aims to focus on the management of creative learning process in Proacademy, an entrepreneurship education unit of Tampere University of Applied Sciences (TAMK) where all coaching, learning and business development activities are focused on facilitating the entrepreneurial path, which consists of five core value‐activities of trust, courage, actions, learning and success.

Design/methodology/approach

TAMK Proacademy implements a unique approach to continuous development of a learning community, based on team learning and self‐managed development of relevant knowledge and skills. The paper describes this process, part of its theoretical basis and major outcomes.

Findings

The shared decision making in Proacademy allows for student‐entrepreneurs to take an active and responsible role in the management of the study programme and leaves enough room for creativity and innovation in practice. Capability of self‐leadership of teams and individuals is enabled by a shared vision and values, and the shared domain of entrepreneurship as the focus of learning activities.

Originality/value

This paper demonstrates the key factors found to be most important in managing a creative organization and it will be of value for anyone investigating learning organizations. It presents an example on how an organization that supports active co‐operation between the university staff and the students can be structured.
The new competitive advantage of automobile manufacturers
Authors: Rugraff Eric
Published: October 2012

Purpose

The literature identifies different sources of competitive advantages. The purpose of this paper is to suggest that an efficient articulation of a Voice behavioral model and an Exit behavioral model can result in a sustained competitive advantage for automobile manufacturers.

Design/methodology/approach

The paper builds on the analytical framework of the global value chain literature to analyze how the combination of hierarchy, relational linkages and market linkages creates additional assets. The case of Volkswagen‐Skoda in the Czech Republic is used to illustrate the combination of Voice and Exit relationships.

Findings

The paper suggests that the competitive advantage of automobile manufacturers crucially depends today on the combination, on the one hand, of the “relational rent” provided by the cooperation with global suppliers, and on the other hand, of the “switching rent” provided by the absence of implication in the relationship with lower‐tier suppliers.

Originality/value

The paper represents an original research initiative that considers the combination of three types of linkages as the source of competitive advantage. The paper uses a case study to exemplify the declination and articulation of the three types of linkages.
Complementarities and coopetition in presence of intangible resources
Authors: Biondi Yuri , Giannoccolo Pierpaolo
Published: October 2012

Purpose

The purpose of this paper is to develop a model of innovative industries which face coopetition: firms compete while committing at the same time to R&D joint ventures and other cooperative agreements. These joint activities are likely to occur in presence of complementarities on demand or supply sides; they raise specific accounting issues concerned with recognition and measurement of intangible resources committed to, and generated from them.

Design/methodology/approach

The paper develops a heuristic industrial economic model characterized by joint utility of outputs for custumers on the demand side, and potential complementarities in R&D activities on the supply side. The authors’ model describes different scenarios generated by alternative corporate pricing strategies. In particular, these strategies (as implemented by firms or imposed by regulators) influence both infrastructure corporate investments and the creation and stability of coopetitive relationships.

Findings

The model scenarios show that especially accounting for intangible resources – related to processes of innovation and R&D – should deserve specific attention. Firms and regulators need to properly account for both hard intangibles that have market prices of reference, and soft and ethereal intangibles that factually have not. A stock method of accounting for intangibles results then which is narrow and biased, because of its focus on hard intangibles alone. A flow method of accounting should be preferred, which tracks the cumulated investment flow of direct and indirect expenditures in innovation and development, properly allocated within and between firms.

Originality/value

The paper argues for regulatory frameworks that enable increasing the positive effects of cooperation while repressing collusive behaviours (technological standardization, fiscal incentives to welfare‐improving innovation and strategy, public research, costumers’ protection, and so forth). Concerning the overall industrial organization, the paper's theoretical analysis shows the need for better recognition and measurement of intangibles and complementarities in costing and pricing, for both corporate and regulatory purposes.
Leveraging tourism social capital: the case of the 2010 Olympic tourism consortium
Authors: Williams Peter W. , Elkhashab Aliaa
Published: October 2012

Purpose

The purpose of this paper is to explore social capital emerging from the collective set of activities pursued by a network of stakeholders leveraging tourism benefits from the 2010 Vancouver Winter Olympic and Paralympic Games (the Games).

Design/methodology/approach

A case study of an Olympic tourism consortium (the Consortium) established to garner tourism benefits from the Games illustrates the forms of social capital development emerging from this initiative. A three‐phased research process involving a literature review, key informant interviews with Consortium stakeholders, and a follow‐up on‐line survey with these representatives informs the study's data collection and analysis process. Aspects of bonding, bridging and linking social capital creation are examined.

Findings

Varying levels of confidence, trust, mutual respect, personal ties, shared values, and human capacity were generated through the Consortium's activities. This social capital was perceived as a valuable but fragile legacy capable of nurturing increased leadership and organizational capacity particularly when tackling issues confronting the industry's overall sustained prosperity. They also felt that the value and momentum of the social capital legacy might be imperiled by a limited appreciation of how to effectively activate it in a post‐Games environment.

Practical implications

Insights are provided into the social capital that networks of stakeholders can generate when working collectively to leverage benefits from sport mega‐events such as the Games.

Originality/value

The research contributes to emerging discussions concerning social capital leveraging in tourism related sport mega‐event management settings.
Six Sigma sales and marketing: application to NCAA basketball
Authors: Salzarulo Peter A. , Krehbiel Timothy C. , Mahar Stephen , Emerson Lance S.
Published: October 2012

Purpose

Today's economic climate has fueled intense competition for entertainment dollars, including those spent on professional and intercollegiate sports. The purpose of this paper is to provide insight and demonstrate the use of the Six Sigma methodology as a way to improve event attendance in a sports marketing setting.

Design/methodology/approach

The research utilizes the define‐measure‐analyze‐improve‐control (DMAIC) sequence to evaluate customer requirements and develop recommendations. Surveys, focus groups, and descriptive statistics comprise an important set of tools utilized to accomplish this aim.

Findings

The paper concludes that Six Sigma can be readily applied to a sports marketing setting by explicitly demonstrating the steps employed to reverse a four‐year decline in attendance for a collegiate men's basketball program.

Originality/value

The paper is unique in detailing the use of Six Sigma, a traditional quality improvement methodology, in a sports marketing setting. It also highlights the unique elements associated with fully implementing a Six Sigma project in such a seasonal setting as an athletic enterprise.
Nocturia: current concepts and future perspectives
Authors: Osman N. I. , Chapple C. R. , Wein A. J.
Published: October 2012

Nocturia is a prevalent highly bothersome urinary symptom that may significantly detriment the health and well‐being of sufferers. It is characterized by waking at night to void, each void preceded and followed by sleep, hence leading to fragmentation of sleep and day‐time tiredness. This may result in reduced productivity in the workplace, which contributes to the significant burden to the wider society that nocturia incurs. Nocturia was traditionally viewed as one of the many urinary tract symptoms that occur due to lower urinary tract dysfunction. However, recently it has been recognized that due to its multi‐factorial aetio‐pathogenesis, nocturia should be viewed as distinct clinical condition in its own right. Careful assessment of the nocturic patient is essential so that treatment strategies are guided by the likely causes. Much research is currently being undertaken into the underlying causes and the optimal management approaches. This review will explore the contemporary status of research on nocturia with a focus on the current and newly available pharmacotherapies.
Transrectal specimen extraction after laparoscopic left colectomy: a case‐matched study
Authors: Christoforidis D. , Clerc D. , Demartines N.
Published: October 2012

Aim  Avoiding ‘mini‐laparotomy’ to extract a colectomy specimen may decrease wound complications and further improve recovery after laparoscopic surgery. The aim of this study was to develop a new technique for transrectal specimen extraction (TRSE) and to compare it with conventional laparoscopy (CL) for left sided colectomy.

Method  Eleven patients with benign disease requiring either sigmoid or left colon resection underwent TRSE. The unfired circular stapler was inserted transanally and used as a guide to suture‐close the recto‐sigmoid junction laparoscopically and as a handle to pull the sutured sigmoid through the opened rectum inside a laparoscopic camera bag. The anvil was inserted into the lumen of the intussuscepted sigmoid and pushed to the level of the anastomosis. The anastomosis was fashioned end‐to‐end in the first patients and side‐to‐end in the following patients to improve safety. Intra‐operative and postoperative outcomes of patients undergoing TRSE were compared with those of a group of 20 patients undergoing CL, who were matched for type of resection, body mass index and age.

Results  The procedure was successful in all but the first patient who was converted to conventional laparoscopic colectomy without any additional morbidity. Two patients in the end‐to‐end anastomosis group, but none in the side‐to‐end group, developed peri‐anastomotic sepsis. Compared with CL, patients undergoing TRSE did not show any significant differences in operative time, recovery or morbidity.

Conclusion  Transrectal specimen extraction after left colectomy using the circular stapler technique is feasible. A side‐to‐end anastomosis appears safer than an end‐to‐end anastomosis. Further studies are needed to explore the potential advantages of this procedure over CL.
Perceptual experience modulates cortical circuits involved in visual awareness
Authors: de Jong Maartje C. , Kourtzi Zoe , van Ee Raymond
Published: October 2012

Successful interactions with the environment entail interpreting ambiguous sensory information. To address this challenge it has been suggested that the brain optimizes performance through experience. Here we used functional magnetic resonance imaging (fMRI) to investigate whether perceptual experience modulates the cortical circuits involved in visual awareness. Using ambiguous visual stimuli (binocular rivalry or ambiguous structure‐from‐motion) we were able to disentangle the co‐occurring influences of stimulus repetition and perceptual repetition. For both types of ambiguous stimuli we observed that the mere repetition of the stimulus evoked an entirely different pattern of activity modulations than the repetition of a particular perceptual interpretation of the stimulus. Regarding stimulus repetition, decreased fMRI responses were evident during binocular rivalry but weaker during 3‐D motion rivalry. Perceptual repetition, on the other hand, entailed increased activity in stimulus‐specific visual brain regions – for binocular rivalry in the early visual regions and for ambiguous structure‐from‐motion in both early as well as higher visual regions. This indicates that the repeated activation of a visual network mediating a particular percept facilitated its later reactivation. Perceptual repetition was also associated with a response change in the parietal cortex that was similar for the two types of ambiguous stimuli, possibly relating to the temporal integration of perceptual information. We suggest that perceptual repetition is associated with a facilitation of neural activity within and between percept‐specific visual networks and parietal networks involved in the temporal integration of perceptual information, thereby enhancing the stability of previously experienced percepts.
Natural selection, plasticity and the emergence of a behavioural syndrome in the wild
Authors: Adriaenssens Bart , Johnsson Jörgen I.
Published: October 2012

Individuals often show consistent behavioural differences where behaviours can form integrated units across functionally different contexts. However, the factors causing and maintaining behavioural syndromes in natural populations remain poorly understood. In this study, we provide evidence for the emergence of a behavioural syndrome during the first months of life in wild brown trout (Salmo trutta). Behavioural traits of trout were scored before and after a 2‐month interval covering a major survival bottleneck, whereupon the consistency and covariance of behaviours were analysed. We found that selection favoured individuals with high activity levels in an open‐field context, a personality trait consistent throughout the duration of the experiment. In addition, a behavioural syndrome emerged over the 2 months in the wild, linking activity to aggressiveness and exploration tendency. These novel results suggest that behavioural syndromes can emerge rapidly in nature from interaction between natural selection and behavioural plasticity affecting single behaviours.
Suspected collagen disorders in the bleeding disorder clinic: A case–control study
Authors: Jackson S. C. , Odiaman L. , Card R. T. , van der Bom J. G. , Poon M‐C.
Published: October 2012

Disorders of collagen are associated with a mild bleeding tendency because of the potential abnormal interaction of collagen, von Willebrand factor (VWF) and platelets required during primary haemostasis and due to generalized soft tissue fragility. Abnormal collagen may contribute to bleeding in existing mucocutaneous bleeding disorders, but the prevalence in this setting is unknown. Generalized symptomatic joint hypermobility (SJH) is common in collagen disorders and may be objectively measured. To assess the association between symptomatic joint hypermobility and mucocutaneous bleeding disorders, we performed a case–control study in which case subjects were 55 consecutive individuals who had visited our bleeding disorder clinic with a diagnosis of von Willebrand disease, low von Willebrand factor levels, mild platelet function disorder or undefined bleeding disorder. Controls were 50 subjects without a bleeding disorder, and were age and gender matched to the cases. All subjects were assessed with: (i) Beighton score for joint hypermobility, (ii) revised Brighton criteria, (iii) Condensed MCMDM1‐VWD bleeding questionnaire, and (iv) haemostasis laboratory studies. The prevalence of SJH/suspected collagen disorder in the bleeding disorder clinic was 24% (13/55) compared with 2% (1/50) in the control population (OR 15, 95% CI 2–121). Seventy‐seven per cent of bleeding disorder clinic SJH subjects (10/13) had a prior personal or family history of Ehlers‐Danlos, Benign Joint Hypermobility Syndrome or Osteogenesis Imperfecta (OI). Symptomatic joint hypermobility was associated with increased odds of an underlying mucocutaneous bleeding disorder. These findings suggest that a collagen disorder is common and often unrecognized in the bleeding disorder clinic as a potential contributor to the bleeding symptoms.
Efficacy of lasers as an adjunct to chemo‐mechanical disinfection of infected root canals: a systematic review
Authors: Fransson H. , Larsson K. M. , Wolf E.
Published: October 2012

The aim was to evaluate the efficacy of various types of lasers used as an adjunct to chemo‐mechanical disinfection of infected root canals with the outcome measures ‘normal periapical condition’ or ‘reduction of microbial load’. PubMed, CENTRAL and ISI Web of Knowledge literature searches with specific indexing terms and a subsequent hand search were made with stated limits and criteria. Relevant publications were retrieved, followed by interpretation. The quality of each included publication was assessed as high, moderate or low. The initial search process yielded 234 publications. All abstracts of these publications were read, and the reference lists of relevant publications were hand‐searched. Ten articles were read in full text and interpreted according to a data extraction form. Five were included in the systematic review and were assessed. A meta‐analysis was impossible to perform because the included studies were heterogeneous with regard to study design, treatment and outcome measures. Positive effects were reported; however, no concluding evidence grade could be made because each included study was judged to have low quality, primarily due to lack of a power analysis, blinding and reproducibility. The evidence grade for whether lasers can be recommended as an adjunct to chemo‐mechanical disinfection of infected root canals was insufficient. This does not necessarily imply that laser should not be used as an adjunct to root canal treatment but instead underscores the need for future high‐quality studies.
Automated, semi‐automated, and manual analyses of anti‐cardiolipin and anti‐β2‐glycoprotein I antibodies in women with a history of miscarriage
Authors: Gutensohn K. , Vossen D. , Strate A. , Kersten J. F. , Hofbauer M. , Krieger T.
Published: October 2012

Introduction

Anti‐cardiolipin and β2‐glycoprotein I antibodies represent important diagnostic parameters in routine hematology. In this study, five different automated, semi‐automated, and manual immunoassays detecting IgG/IgM anti‐cardiolipin and anti‐β2‐glycoprotein I antibodies were tested.

Methods

A total of 162 samples from women with a history of miscarriage were recruited from 110 different G&O outpatient centers in Germany.

Results

For both anti‐cardiolipin and anti‐β2‐glycoprotein I antibodies, considerable differences in the percentage of positive results were seen between all five methods, and itemization of all positive test results revealed a poor accordance. These findings were confirmed by Cohen's kappa coefficients.

Conclusion

Our study revealed a moderate to poor accordance between five different test systems for anti‐cardiolipin and anti‐β2‐glycoprotein I antibodies. Such deviations may result in clinical misinterpretation of data and may lead to wrong therapeutic consequences. Therefore, further standardization of all tests for anti‐phospholipid antibodies should be achieved.
Phylogeny of the Liliales (Monocotyledons) with special emphasis on data partition congruence and RNA editing
Authors: Petersen Gitte , Seberg Ole , Davis Jerrold I.
Published: October 2012

A phylogenetic analysis of the monocot order Liliales was performed using sequence data from three mitochondrial (atp1, cob, nad5) and two plastid genes (rbcL, ndhF). The complete data matrix includes 46 terminals representing all 10 families currently included in Liliales. The two major partitions, mitochondrial and plastid data, were congruent, and parsimony analysis resulted in 50 equally parsimonious trees and a well resolved consensus tree confirming monophyly of all families. Mitochondrial genes are known to include RNA edited sites, and in some cases unprocessed genes are replaced by retro‐processed gene copies, that is processed paralogs. To test the effects on phylogeny reconstruction of predicted edited sites and potentially unintentionally sampled processed paralogs, a number of analyses were performed using subsets of the complete data matrix. In general, predicted edited sites were more homoplasious than the other characters and increased incongruence among most data partitions. The predicted edited sites have a non‐random phylogenetic signal in conflict with the signal of the non‐edited sites. The potentially misleading signal was caused partially by the apparent presence of processed paralogs in Galanthus (Amaryllidaceae), part of the outgroup, but also by a deviating evolutionary pattern of predicted edited sites in Liliaceae compared with the remainder of the Liliales. Despite the problems that processed paralogs may cause, we argue that they should not a priori be excluded from phylogenetic analysis.
Shifting thresholds and changing degradation patterns: climate change effects on the simulated long‐term response of a semi‐arid savanna to grazing
Authors: Lohmann Dirk , Tietjen Britta , Blaum Niels , Joubert David F. , Jeltsch Florian
Published: October 2012

1. The complex, nonlinear response of dryland systems to grazing and climatic variations is a challenge to management of these lands. Predicted climatic changes will impact the desertification of drylands under domestic livestock production. Consequently, there is an urgent need to understand the response of drylands to grazing under climate change.

2. We enhanced and parameterized an ecohydrological savanna model to assess the impacts of a range of climate change scenarios on the response of a semi‐arid African savanna to grazing. We focused on the effects of temperature and CO2 level increase in combination with changes in inter‐ and intra‐annual precipitation patterns on the long‐term dynamics of three major plant functional types.

3. We found that the capacity of the savanna to sustain livestock grazing was strongly influenced by climate change. Increased mean annual precipitation and changes in intra‐annual precipitation pattern have the potential to slightly increase carrying capacities of the system. In contrast, decreased precipitation, higher interannual variation and temperature increase are leading to a severe decline of carrying capacities owing to losses of the perennial grass biomass.

4. Semi‐arid rangelands will be at lower risk of shrub encroachment and encroachment will be less intense under future climatic conditions. This finding holds in spite of elevated levels of atmospheric CO2 and irrespective of changes in precipitation pattern, because of the drought sensitivity of germination and establishment of encroaching species.

5. Synthesis and applications. Changes in livestock carrying capacities, both positive and negative, mainly depend on the highly uncertain future rainfall conditions. However, independent of the specific changes, shrub encroachment becomes less likely and in many cases less severe. Thus, managers of semi‐arid rangelands should shift their focus from woody vegetation towards perennial grass species as indicators for rangeland degradation. Furthermore, the resulting reduced competition from woody vegetation has the potential to facilitate ecosystem restoration measures such as re‐introduction of desirable plant species that are only little promising or infeasible under current climatic conditions. On a global scale, the reductions in standing biomass resulting from altered degradation dynamics of semi‐arid rangelands can have negative impacts on carbon sequestration.
Implementation uncertainty when using recreational hunting to manage carnivores
Authors: Bischof Richard , Nilsen Erlend B. , Brøseth Henrik , Männil Peep , Ozoliņš Jaānis , Linnell John D. C.
Published: October 2012

1. Wildlife managers often rely on resource users, such as recreational or commercial hunters, to achieve management goals. The use of hunters to control wildlife populations is especially common for predators and ungulates, but managers cannot assume that hunters will always fill annual quotas set by the authorities. It has been advocated that resource management models should account for uncertainty in how harvest rules are realized, requiring that this implementation uncertainty be estimated.

2. We used a survival analysis framework and long‐term harvest data from large carnivore management systems in three countries (Estonia, Latvia and Norway) involving four species (brown bear, grey wolf, Eurasian lynx and wolverine) to estimate the performance of hunters with respect to harvest goals set by managers.

3. Variation in hunter quota‐filling performance was substantial, ranging from 40% for wolverine in Norway to nearly 100% for lynx in Latvia. Seasonal and regional variation was also high within country–species pairs. We detected a positive relationship between the instantaneous potential to fill a quota slot and the relative availability of the target species for both wolverine and lynx in Norway.

4. Survivor curves and hazards – with survival time measured as the time from the start of a season until a quota slot is filled – can indicate the extent to which managers can influence harvest through adjustments of season duration and quota limits.

5. Synthesis and applications. We investigated seven systems where authorities use recreational hunting to manage large carnivore populations. The variation and magnitude of deviation from harvest goals was substantial, underlining the need to incorporate implementation uncertainty into resource management models and decisions‐making. We illustrate how survival analysis can be used by managers to estimate the performance of resource users with respect to achieving harvest goals set by managers. The findings in this study come at an opportune time given the growing popularity of management strategy evaluation (MSE) models in fisheries and a push towards incorporating MSE into terrestrial harvest management.