Early recoil after balloon angioplasty of tibial artery obstructions in patients with critical limb ischemia.

PURPOSE To assess the extent of early recoil in patients with critical limb ischemia (CLI) undergoing conventional tibial balloon angioplasty. METHODS Our hypothesis was that early recoil, defined as lumen compromise >10%, is frequent and accounts for considerable luminal narrowing after tibial angioplasty, promoting restenosis. To test this theory, 30 consecutive CLI patients (18 men; mean age 76.2±12.1 years) were angiographically evaluated immediately after tibial balloon angioplasty and 15 minutes later. Half the patients were diabetics. Target lesions included anterior and posterior tibial arteries and the peroneal artery with / without the tibioperoneal trunk. Mean tibial lesion length was 83.8 mm. Early elastic recoil was determined on the basis of minimal lumen diameter (MLD) measurements at baseline (MLDbaseline), immediately after tibial balloon angioplasty (MLDpostdilation), and 15 minutes thereafter (MLD15min). RESULTS Elastic recoil was observed in 29 (97%) patients with a mean luminal compromise of 29% according to MLD measurements (MLDbaseline 0.23 mm, MLD postdilation 2.0 mm, and MLD15min 1.47 mm). CONCLUSION Early recoil is frequently observed in CLI patients undergoing tibial angioplasty and may significantly contribute to restenosis. These findings support the role of dedicated mechanical scaffolding approaches for the prevention of restenosis in tibial arteries.

Visual disturbance following sclerotherapy for varicose veins, reticular veins and telangiectasias: a systematic literature review.

The objective of the study was to review the literature reporting visual disturbance (VD)following sclerotherapy for varicose veins. Underlying mechanisms will be discussed. A literature search of the databases Medline and Google Scholar was performed. Original articles including randomized trials, case series and case reports reporting VD in humans following sclerotherapy for varicose veins were included. Additional references were also obtained if they had been referenced in related publications. The search yielded 4948 results of which 25 reports were found to meet the inclusion criteria. In larger series with at least 500 included patients the prevalence of VD following sclerotherapy ranges from 0.09% to 2%. In most reports foam sclerotherapy was associated with VD (19); exclusive use of liquid sclerosant was reported in two cases, some reports included foam and liquid sclerosant (4). There were no persistent visual disorders reported. VD occurred with polidocanol and sodium tetradecyl sulphate in different concentrations (0.25–3%). Various forms of foam preparation including various ways of foam production and the liquid –air ratio (1 or 2 parts of liquid mixed with 3, 4 or 5 parts of air) were reported in association with the occurrence of VD. VDs following sclerotherapy for varicose veins are rare and all reported events were transient. Bubble embolism or any kind of embolism seems unlikely to be the only underlying mechanism. A systemic inflammatory response following sclerotherapy has been suggested. Further research to clarify the mechanism of action of sclerosants is required.

Persistence of Artemisia steppe in the Tangra Yumco Basin, west-central Tibet, China: despite or in consequence of Holocene lake-level changes?

The closed Tangra Yumco Basin underwent the strongest Quaternary lake-level changes so far recorded on the Tibetan Plateau. It was hitherto unknown what effect this had on local Holocene vegetation development. A 3.6-m sediment core from a recessional lake terrace at 4,700 m a.s.l., 160 m above the present lake level of Tangra Yumco, was studied to reconstruct Holocene flooding phases (sedimentology and ostracod analyses), vegetation dynamics and human influence (palynology, charcoal and coprophilous fungi analyses). Peat at the base of the profile proves lake level was below 4,700 m a.s.l. during the Pleistocene/Holocene transition. A deep-lake phase started after 11 cal ka BP, but the ostracod record indicates the level was not higher than similar to 4,720 m a.s.l. (180 m above present) and decreased gradually after the early Holocene maximum. Additional sediment ages from the basin suggest recession of Tangra Yumco from the coring site after 2.6 cal ka BP, with a shallow local lake persisting at the site until similar to 1 cal ka BP. The final peat formation indicates drier conditions thereafter. Persistence of Artemisia steppe during the Holocene lake high-stand resembles palynological records from west Tibet that indicate early Holocene aridity, in spite of high lake levels that may have resulted from meltwater input. Yet pollen assemblages indicate humidity closer to that of present potential forest areas near Lhasa, with 500-600 mm annual precipitation. Thus, the early mid-Holocene humidity was sufficient to sustain at least juniper forest, but Artemisia dominance persisted as a consequence of a combination of environmental disturbances such as (1) strong early Holocene climate fluctuations, (2) inundation of habitats suitable for forest, (3) extensive water surfaces that served as barriers to terrestrial diaspore transport from refuge areas, (4) strong erosion that denuded the non-flooded upper slopes and (5) increasing human influence since the late glacial.

An Architecture to offer Cloud-Based Radio Access Network as a Service

This paper addresses the novel notion of offering a radio access network as a service. Its components may be instantiated on general purpose platforms with pooled resources (both radio and hardware ones) dimensioned on-demand, elastically and following the pay-per-use principle. A novel architecture is proposed that supports this concept. The architecture's success is in its modularity, well-defined functional elements and clean separation between operational and control functions. By moving much processing traditionally located in hardware for computation in the cloud, it allows the optimisation of hardware utilization and reduction of deployment and operation costs. It enables operators to upgrade their network as well as quickly deploy and adapt resources to demand. Also, new players may easily enter the market, permitting a virtual network operator to provide connectivity to its users.

The use of unmanned aerial vehicles and wireless sensor networks for spraying pesticides

The application of pesticides and fertilizers in agricultural areas is of crucial importance for crop yields. The use of aircrafts is becoming increasingly common in carrying out this task mainly because of their speed and effectiveness in the spraying operation. However, some factors may reduce the yield, or even cause damage (e.g., crop areas not covered in the spraying process, overlapping spraying of crop areas, applying pesticides on the outer edge of the crop). Weather conditions, such as the intensity and direction of the wind while spraying, add further complexity to the problem of maintaining control. In this paper, we describe an architecture to address the problem of self-adjustment of the UAV routes when spraying chemicals in a crop field. We propose and evaluate an algorithm to adjust the UAV route to changes in wind intensity and direction. The algorithm to adapt the path runs in the UAV and its input is the feedback obtained from the wireless sensor network (WSN) deployed in the crop field. Moreover, we evaluate the impact of the number of communication messages between the UAV and the WSN. The results show that the use of the feedback information from the sensors to make adjustments to the routes could significantly reduce the waste of pesticides and fertilizers.

Agent-based Content Retrieval for Opportunistic Content-Centric Networks

In this paper, we describe agent-based content retrieval for opportunistic networks, where requesters can delegate content retrieval to agents, which retrieve the content on their behalf. The approach has been implemented in CCNx, the open source CCN framework, and evaluated on Android smart phones. Evaluations have shown that the overhead of agent delegation is only noticeable for very small content. For content larger than 4MB, agent-based content retrieval can even result in a throughput increase of 20% compared to standard CCN download applications. The requester asks every probe interval for agents that have retrieved the desired content. Evaluations have shown that a probe interval of 30s delivers the best overall performance in our scenario because the number of transmitted notification messages can be decreased by up to 80% without significantly increasing the download time.

Information-Centric Networking in Mobile and Opportunistic Networks

Information Centric Networking (ICN) as an emerging paradigm for the Future Internet has initially been rather focusing on bandwidth savings in wired networks, but there might also be some significant potential to support communication in mobile wireless networks as well as opportunistic network scenarios, where end systems have spontaneous but time-limited contact to exchange data. This chapter addresses the reasoning why ICN has an important role in mobile and opportunistic networks by identifying several challenges in mobile and opportunistic Information-Centric Networks and discussing appropriate solutions for them. In particular, it discusses the issues of receiver and source mobility. Source mobility needs special attention. Solutions based on routing protocol extensions, indirection, and separation of name resolution and data transfer are discussed. Moreover, the chapter presents solutions for problems in opportunistic Information-Centric Networks. Among those are mechanisms for efficient content discovery in neighbour nodes, resume mechanisms to recover from intermittent connectivity disruptions, a novel agent delegation mechanisms to offload content discovery and delivery to mobile agent nodes, and the exploitation of overhearing to populate routing tables of mobile nodes. Some preliminary performance evaluation results of these developed mechanisms are provided.

Expectation-based types of volunteers in Swiss sports clubs

Volunteer research in sports clubs has paid hardly any attention to the individual expectations even though matching conditions to the specific volunteer’s expectations represents a major management challenge. This article presents a person-oriented approach to the expectation profiles of volunteers that delivers the basis for identifying different volunteer segments. The approach assumes explicitly that volunteers in sports clubs develop specific expectations regarding their working conditions. These expectations were determined in a sample of 441 members of 45 selected sports clubs. Proximately, a cluster analysis revealed that volunteers vary in their expectations regarding voluntary work. Four different types of volunteers could be identified: (1) recognition seekers, (2) material incentive seekers, (3) participation and communication seekers, and (4) support seekers. These “expectation-based volunteer types” could also be characterized in socioeconomic, membershiprelated, and volunteer-work-related terms. These types could serve as a basis for designing specific voluntary work conditions in sports clubs.

Does culture really matter in sports participation? The impact of socio-cultural factors on sports behaviour in Switzerland

The physical activity of the Swiss population differs considerably depending on the linguistic region. German speakers are more often physically active than people living in the French or Italian-speaking part of Switzerland (Stamm & Lamprecht, 2011). This study analyses how socio-cultural factors correlate with sports participation for adolescents and young adults. In order to analyse this research question, Bourdieu’s concept of habitus (1984) has been adapted and used as a theoretical background. This sport-related concept of habitus considers culturally determined values, the attribution of meaning and patterns of action such as the understanding of sports, the importance of sports, body, health or leisure. On this basis, the sport-related habitus and the practical relevance of sports participation has been empirically reconstructed for adolescents and young adults aged 15 to 25 through a qualitative study including guideline-based interviews with German (n=6) and French (n=4) speaking adolescents and young adults, as well as a quantitative survey in a German (n=106) and a French (n=99) speaking commune of Switzerland. Initial findings reveal that young German speakers associate sports with self-discipline (χ²(1, N=205)= 8.223, p<.005, V=.200) and fitness (χ²(1, N=205)= 21.989, p<.005, V=.328) whereas young French speakers are more likely to relate health (χ²(1, N=205)= 9.455, p<.005, V=.215), effort and perspiration (χ²(1, N=205)= 18.835, p<.005, V=.303) to sports. Similarly, the understanding of body and health as well as the attitude towards leisure differs between the German and French speaking parts of Switzerland. This study illustrates that the concept of sports habitus is culturally shaped and therefore may be fruitful in further analyses. Bourdieu, P. (1984). Distinction. A Social Critique of the Judgement of Taste. Cambridge: Harvard University Press. Stamm, H. & Lamprecht, M. (2008). Swiss sports participation in an international perspective. European Journal for Sport and Society, 8 (1+2), 15-29.

Entscheidungsprozesse in Sportvereinen in Zusammenhang mit externer Beratung

Introduction: Verbunden mit den steigenden Mitgliederzahlen, fällt es Sportvereinen zunehmend schwer, die vielfältige Nachfrage zu bedienen und die hohen Erwartungen zu erfüllen. Viele Schweizer Sportvereine bekunden Probleme, insbesondere im Bereich der Gewinnung und Bindung von ehrenamtlichen Mitarbeitern (Lamprecht, Fischer & Stamm, 2012). Da ca. 90 % der Schweizer Sportvereine ehrenamtlich organisiert sind und die Erfüllung des Vereinszwecks direkt mit dem ehrenamtlichen Engagement der Vereinsmitglieder zusammenspielt, führt der Mangel an Ehrenamtlichen zu erheblichen Problemen. Sportvereine können diese skizzierten Herausforderungen aufgrund deren Komplexität und den eigenen begrenzten Ressourcen nicht mehr alleine bewältigen und sind deshalb auf Wissen von aussen angewiesen (Bette, 2009). Damit stellt sich zugleich die Frage, inwieweit von aussen an Sportvereine herangetragene Steuerungspraktiken und Beratungsprogramme (z.B. durch Sportverbände) in Bezug auf den Umgang mit personalen Problemlagen wirksam sind oder nicht. So lässt sich vielfach beobachten, dass standardisierte Beratungsinputs im Verein zu unterschiedlichen Konsequenzen führen. Demnach ist zu vermuten, dass externe Impulse vereinsintern in unterschiedlicher Art und Weise interpretiert und in Vereinsrealität übersetzt (programmiert) werden. Solche Prozesse sind in hohem Masse an die vereinsspezifischen Reproduktionsbedingungen, also Entscheidungsprozesse gebunden. Deshalb stellt sich die Frage: Welche organisationalen Entscheidungsprozesse im Allgemeinen und speziell in Zusammenhang mit externer Beratung sind in Sportvereinen zu beobachten? Methods: Die Daten zur Analyse der Entscheidungsprozesse wurden im Rahmen des Projekts „Mehr Freiwillige im Fussballverein“ (MFiF) in Kooperation mit dem Schweizerischen Fussballverband (SFV) in elf Fussballvereinen erhoben. Die Interventionsstudie umfasst vier Aspekte: (1) systematischer Ansatz, (2) Einbezug aller Vereinsmitglieder, (3) konsequente Implementation in den Fussballvereinen und (4) eine längerfristige Bindungsstrategie für ehrenamtliche Mitarbeiter. Die Daten wurden einerseits über Fragebogen zur Struktur des Vereins und den Ergebnissen des Projekts erhoben, andererseits wurden leitfadengestützte Interviews mit den führenden Vereinsvertretern in den Projektgruppen durchgeführt und anschliessend anhand qualitativer Inhaltsanalyse ausgewertet (Mayring, 2010). Results: Die Auswertung der Interviews zeigt auf, dass verschiedene Faktoren für eine erfolgreiche Umsetzung einer Gewinnungs- und Bindungsstrategie entscheidend sind. Einerseits wird die Rolle der zuständigen Personen unterschiedlich interpretiert und deshalb fällt das Engagement im Entscheidungsprozess unterschiedlich aus. Die Bandbreite reicht vom Informator über den Moderator bis hin zum aktiven Promotor. Mit Blick auf die externe Beratung lässt sich erkennen, dass die Fussballvereine die Unterstützung unterschiedlich einordnen. Dem traditionellen Beratungskonzept folgend anerkennen Vereine die externe Beratung als bewährte Musterlösung und verfolgen unreflektiert die vorgeschlagene Lösungsstrategie. Gleichzeitig lässt sich eine zweite Gruppe von Vereinen entsprechend dem systemischen Beratungskonzept durch die externe Beratung irritieren und hinterfragt die eigene Struktur und sucht nach eine passenden Lösungsstrategie. Discussion/Conclusion: Die Untersuchung zeigt auf, dass externe Vereinsberatung sowohl mimetisch, wie auch als systemische Beratung interpretiert zu Verbesserungen im Bereich des Ehrenamtmanagements in Sportvereinen führen kann. References: Bette, K.-H. (2009). Beratung von Sportorganisationen: Konzepte und Voraussetzungen. In C. Breuer & A. Thiel (Hrsg.), Handbuch Sportmanagement (2. Aufl., S. 139-155). Schorndorf: Hofmann. Lamprecht, M., Fischer, A., & Stamm, H.-P. (2012). Sportvereine in der Schweiz. Strukturen, Leistungen, Herausforderungen. Zürich: Seismo. Mayring, P. (2010). Qualitative Inhaltsanalyse: Grundlagen und Techniken (11. Aufl.). Hemsbach: Beltz.