bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of pingers on the behaviour of bottlenose dolphins
Authors: Leeney Ruth H. , Berrow Simon , McGrath David , O'Brien Joanne , Cosgrove Ronan , Godley Brendan J.
Published: February 2007

Trials were carried out in the Shannon estuary, Ireland, to test the effects of continuous (CPs) and responsive pingers (RPs) on bottlenose dolphin behaviour. In controlled trials, active and control pingers were deployed on fixed moorings, with T-PODs—acoustic monitoring devices to detect cetacean activity. In a separate trial, pingers were deployed from a moving boat which actively located dolphin groups in the estuary, and dolphin behaviour was recorded. In the static trials, overall detection rates of dolphin vocalizations on the T-POD were significantly lower in the presence of active CPs, but this was not the case for RPs. Mean inter-click interval values were longer for click trains produced in the presence of inactive RPs than for active RPs, active or inactive CPs. In boat-based trials, both active CPs and RPs appeared to affect bottlenose dolphin behaviour, whereby dolphins immediately left the area at speed and in a highly directional manner, involving frequent leaps.
SST fronts and the summer sperm whale distribution in the north-west Mediterranean Sea
Authors: Gannier Alexandre , Praca Emilie
Published: February 2007

The relative distribution of sperm whales (Physeter macrocephalus) and sea surface temperature (SST) fronts have been studied in summer in the north-western Mediterranean Sea. We used passive acoustic data (778 samples) obtained offshore during dedicated surveys between 1999 and 2004 and Pathfinder/Modis remote sensing data to compute front maps and to calculate mean distances from sperm whale detections (N=132) to SST-fronts. Mean distances from sperm whale acoustic detections to SST-fronts were significantly lower (10.4 km) than from other acoustic samples to those fronts (17.0 km). The same result was obtained when calculating distances from sperm whales to the North Balearic Front surface signature. If sperm whales are commonly observed along the continental slope, we showed that offshore individuals were located close to SST-fronts. This bimodal distribution in the north-western Mediterranean is linked to sperm whale feeding strategy, demonstrating ecological opportunistic behaviour in this high level predator.
Neural network-based sperm whale click classification
Authors: van der Schaar M. , Delory E. , Català A. , André M.
Published: February 2007

Recordings of a group of foraging sperm whales usually result in a mixture of clicks from different animals. To analyse the click sequences of individual whales these clicks need to be separated, and for this an automatic classifier would be preferred. Here we study the use of a radial basis function network to perform the separation. The neural network's ability to discriminate between different whales was tested with six data sets of individually diving males. The data consisted of five shorter click trains and one complete dive which was especially important to evaluate the capacity of the network to generalize. The network was trained with characteristics extracted from the six click series with the help of a wavelet packet-based local discriminant basis. The selected features were separated in a training set containing 50 clicks of each data set and a validation set with the remaining clicks. After the network was trained it could correctly classify around 90% of the short click series, while for the entire dive this percentage was around 78%.
Passive acoustic tomography: new concepts and applications using marine mammals: a review
Authors: Gervaise C. , Vallez S. , Ioana C. , Stephan Y. , Simard Y.
Published: February 2007

This paper presents the new concept of passive acoustic tomography which allows ocean data collection with a passive acoustic remote sensing process. The originality lies in using acoustic sources of opportunity such as surface noise, radiated ship noise and marine mammal calls. Such use of passive tomography is a promising way to reduce acoustic emissions in oceans. A review is first presented, including the description of new concepts of covert active, assisted passive and autonomous tomography, followed by applications on real world data. Under the assumptions of multipath propagation and measurements performed by a sparse network of hydrophones, a time–frequency processor is proposed to simultaneously estimate the source location and the impulse response of the propagation channel for marine mammal calls used as opportunistic sources (multipath structure, time delay and attenuation are estimated). Promising results are obtained on real data coming from the Laurentian channel where wideband beluga calls (1 to 3 kHz) are measured by a sparse network of 6 bottom hydrophones.
Using T-PODs to investigate the echolocation of coastal bottlenose dolphins
Authors: Philpott E. , Englund A. , Ingram S. , Rogan E.
Published: February 2007

We investigated the feasibility of using a T-POD, a passive acoustic dolphin detector system, to monitor bottlenose dolphins in the Shannon Estuary, Ireland, from 27 June to 18 August 2005. A v.3 T-POD, logging alternate minutes, was moored in view of an observation site. Land-based theodolite tracking was used to record the position of the closest animal, school size and activity of the closest dolphin school to the T-POD. All cetacean detections on the T-POD synchronous with shore watches in sea states ≤2 were analysed. A total of 94 schools were observed at distances up to 8000 m from the observer. Acoustic detections corresponded well with visual detections, with 82% of the dolphin schools observed within 500 m of the T-POD detected acoustically. The furthest distance dolphins were observed from the T-POD during periods of acoustic detection was 1246 m. Twelve acoustic encounters were logged without corresponding visual detections, four of which may represent false positives. School size did not affect the acoustic detectability of the dolphins, as there was no difference in the size of schools observed with or without corresponding acoustic detections (Kruskal–Wallis, P=0.64). Similarly no relationship was found between acoustic detections and school sizes at different distances to the T-POD (linear regression P=0.5, r2=0.01). Acoustic encounters did not vary in relation to diel patterns (Mann–Whitney, P=0.13) but were related to tidal state (χ2=40.2, P=0.00, df=11) with more encounters logged in the 4 h after high water, probably reflecting prey-related changes in habitat use. T-POD detections correlated well with visual observations and although detection is likely to vary according to T-POD specification, sensitivity and the conditions at the deployment site, the T-POD is a useful tool that has been shown to offer the possibility of continuous monitoring, something that is difficult to achieve with visual methods alone.
On the possibility of detecting surfacing sperm whales at risk of collision using others' foraging clicks
Authors: Delory E. , André M. , Navarro Mesa J.-L. , van der Schaar M.
Published: February 2007

Cetaceans are prone to collisions with fast vessels, and in areas of high cetacean and vessel density such as in the Canary Islands, the sperm whale (Physeter macrocephalus) is of great concern. Sperm whales are highly vocal and can be localized with passive sonar, but, when at or near the surface, they tend to stop vocalizing, i.e. when they are most at risk. Regrettably, ship-borne active solutions have proven inefficient due to the short detection range and the ships' high-speeds. Our objective in this paper is to evaluate the efficiency of an original passive sonar solution that would use vocalizing whale clicks at depth as acoustic sources to detect silent whales. This solution could be a non-invasive complementary component of a more complex passive localization whale anti-collision system. To meet this aim, a simulation tool for 3D acoustic propagation was designed in which a wideband Nx2D ray solution of the wave equation simulates a passive solution consisting of an arbitrary number of active acoustic sources, an illuminated object, and a receiver, all positioned in a three-dimensional space with arbitrary bathymetry. Both curved and straight ray solutions were implemented, the latter providing greater computational speeds at the expense of temporal and angular precision. The software recreates the resulting sound mixture of direct, reverberated and target back-scattered signals arriving at the array sensors for any array configuration, any number of sources and one target. Simulations show the application of the concept for the Canary Islands, with a detection range upper bound of the order of one kilometre.
Methods for investigating measurement error in cetacean line-transect surveys
Authors: Williams Rob , Leaper Russell , Zerbini Alexandre N. , Hammond Philip S.
Published: February 2007

Line-transect estimates of abundance generally assume that distances and angles to animals are measured without error. Biased distance measurements will lead to corresponding bias in abundance estimates. Efforts to address this have been made, but measuring distance to cetaceans at sea remains problematic. Four distance-estimation experiments were conducted to explore relationships between estimated and measured distance. Heteroscedasticity was found in all four cases. Preliminary evidence suggested that an observer differed in the ability to judge distance to fixed, continuously-visible cues and ephemeral, cetacean cues, which calls into the question the common practice of using marker buoys as cetacean proxies in distance-estimation experiments. Two studies found visual estimates to be positively biased, and two studies found reticule measurements to be negatively biased. Suitable correction factors were developed to address systematic bias from visual estimates, but these varied widely among observers and were sometimes non-linear. Errors in three studies showed positive skew, suggesting that ranges were overestimated to a larger degree than they were underestimated. If reticule and photogrammetric measurements yield log-normally distributed errors generally, then a least-squares regression will always overestimate the correction factor, underestimate range, and overestimate abundance. Photogrammetric methods to measure range to cetaceans performed well, and their use is encouraged. When measurements cannot be made to all sightings, however, it is recommended that experiments be conducted that generate sufficient sample size (of the target species, across typical survey conditions, and beyond the maximum range that most estimates will be made during the survey) to assess error distributions, examine evidence for non-linearity, and to consider inter-observer differences. Distance experiments, and training on survey protocols, can be conducted using ships of opportunity prior to the beginning of a dedicated survey, which would improve observer efficiency while reducing the costs of dedicated vessel time.
Variability in the diet of bottlenose dolphin, Tursiops truncatus, in Galician waters, north-western Spain, 1990–2005
Authors: Santos M.B. , Fernández R. , López A. , Martínez J.A. , Pierce G.J.
Published: February 2007

We describe the diet of bottlenose dolphins Tursiops truncatus in Galician waters, north-western Spain, based on 82 non-empty stomachs recovered and analysed from stranded animals between 1990 and 2005, quantifying interannual and seasonal variation in the diet, as well as dietary variation related to sex and size. The most important prey species (in terms of numerical importance and biomass) were blue whiting (Micromesistius poutassou) and hake (Merluccius merluccius), both of high commercial importance in Galician waters. Most blue whiting eaten by dolphins were mature fish but the estimated total consumption was relatively low (around 10%) compared to Spanish fishery landings of this species. In contrast, most hake eaten by dolphins were probably immature but the estimated total consumption is more than 20% of current annual fishery landings. The diet of by-caught animals, which made up around one third of the sample, was very similar to that in the overall sample. Although bottlenose dolphins are often seen close inshore, evidence from the diet suggests that they feed at the shelf edge. Evidence was found of ontogenetic dietary shifts and differences between diets of male and female dolphins. There were also clear changes in average diet over the 16-year study period, although there was no evidence that they were in response to changes in fish abundance. The amount of hake in the diet remained stable against a background of falling local abundance while the amount of blue whiting declined despite an increase in spawning stock size.
The impact of stress on cytokine and haptoglobin mRNA expression in blood samples from harbour porpoises (Phocoena phocoena)
Authors: Fonfara S. , Siebert U. , Prange A. , Colijn F.
Published: February 2007

Cytokines are important cell mediators involved in immune responses. Their expression can be modulated by numerous factors, including stress. The aim of this study was to compare cytokine mRNA expression from harbour porpoises exposed to different environments. Blood samples were taken from two healthy porpoises living in captivity at the Fjord and Belt Centre Kerteminde, Denmark, and from four wild porpoises accidentally caught in Danish waters. Real-time RT-PCR was used to quantify the transcription of interleukin-(IL)-1β, IL-2, -4, -6, -10, tumour necrosis factor-(TNF)-α, transforming growth factor-(TGF)-β and the acute phase protein haptoglobin. This revealed downregulation of the pro-inflammatory cytokines IL-1β, IL-2, IL-6 and TNFα, and a switch towards the T-helper-cell-(Th)2- and Th3-cytokines, IL-4 and TGFβ, in blood samples of the wild-captured animals. This indicated a shift towards immunomodulatory cytokines. In addition, cortisol levels were increased in the wild-caught porpoises. These results are suggestive of stress-induced modulation of the immune responses in the accidentally caught animals. The current study indicates that the expression pattern of these cytokines and the estimation of the Th1- to Th2- and Th3-cytokine mRNA ratios might be a useful indicator to analyse the influence of stress on the immune system in harbour porpoises.
Twenty years of marine mammal research in Europe
Authors: Evans Peter G.H. , Pierce Graham J. , André Michel
Published: February 2007

This special issue on marine mammals marks the 20th anniversary of the European Cetacean Society (ECS). The Society's 2006 conference was held in Gdynia, Poland in April, with the theme of ‘Marine mammals and man in coastal ecosystems: can they co-exist?’ Several of the papers contained in this volume describe work that was presented at this conference, and most relate to research carried out by ECS members.
An analysis of the population genetics of potential multi-drug resistance inWuchereria bancroftidue to combination chemotherapy
Authors: SCHWAB A. E. , CHURCHER T. S. , SCHWAB A. J. , BASÁÑEZ M.-G. , PRICHARD R. K.
Published: February 2007

Currently, annual mass treatments with albendazole (ABZ) plus ivermectin (IVM) or diethylcarbamazine (DEC) are administered under the Global Programme to Eliminate Lymphatic Filariasis (GPELF). Drug resistance against both ABZ and IVM is prevalent in nematodes of veterinary importance, raising awareness that if anthelmintic resistance were to develop amongWuchereria bancroftipopulations, this would jeopardize GPELF's goals. Genetic structure was incorporated into an existing transmission dynamics model for lymphatic filariasis (LF) to investigate the potential development of concurrent resistance to ABZ and IVM. The resultant models explore the impact of different inheritance modes of resistance to ABZ and IVM on the likely risk of treatment failure under our model assumptions. Results indicate that under ABZ+IVM combination, selection for resistance to one drug is enhanced if resistance to the other drug is already present. Excess parasite homozygosity may increase selection for dominant IVM resistanceviaenhancing the frequency of recessive ABZ resistance. The model predicts that if multiple resistance genes are associated with different efficacy properties of a drug combination, then examining changes at single loci may be misleading. Sampling schemes in genetic epidemiological surveys investigating the frequency of an allele under selection should consider host age, as individuals of different ages may acquire parasites at different rates.
System-controlled user interaction within the service robotic control architecture MASSiVE
Authors: Prenzel Oliver , Martens Christian , Cyriacks Marco , Wang Chao , Gräser Axel
Published: February 2007

This paper presents an approach to reduce the technical complexity of a service robotic system by means of systematic and well-balanced user-involvement. By taking advantage of the user's cognitive capabilities during task execution, a technically manageable robotic system, which is able to execute tasks on a high level of abstraction reliably and robustly, emerges. For the realisation of this approach, the control architecture MASSiVE has been implemented, which is used for the control of the rehabilitation robot FRIEND II. It supports task execution on the basis of a priori defined and formally verified task-knowledge. This task-knowledge contains all possible sequences of operations as well as the symbolic representation of objects required for the execution of a specific task. The seamless integration of user interactions into this task-knowledge, in combination with MASSiVE's user-adapted human–machine interface layer, enables the system to deliberately interact with the user during run-time.
The Limits of Censorship
Authors: REINELT JANELLE
Published: February 2007

The rhetoric of censorship is increasingly invoked in the West in response to the curtailment of civil liberties, often as a result of new repressive legislation arising from efforts to fight terrorism. However, while agreeing that serious issues concerning censorship are arising for artists with more frequency, this essay argues that caution needs to be exercised concerning the charge of ‘censorship’, and that theatre artists and scholars need sustained and nuanced analyses of what constitutes censorship and what extenuating circumstances may accompany events that at first glance bear the marks of the censor.
Inside Fateh Azzam's Baggage: Monologue and Forced Migration
Authors: PAGAN NICHOLAS O.
Published: February 2007

The work of Palestinian playwright Fateh Samih Azzam arises from his experience growing up as a refugee and from his strong commitment to human rights. His latest play, Baggage, is set in a crowded airport where a lone Traveler re-enacts the Catastrophe of 1948 and its consequences. This article begins by positioning Azzam's work in relation to post-1948 Palestinian theatre. It then looks in detail at how Baggage, written as a monodrama, incorporates a number of devices including airport announcements and other voiceovers to imbue monologue with dialogue. The question of the relationship between monologue and dialogue is examined in the context of the emergence of the ‘political’ in performance and especially in relation to Jon Erickson's recent contention that dialogues facilitate the representation of conflicting world views whereas monologues tend to be ‘vehicles for the overarching world view of the playwright’. Next, it discusses a recent staging of Baggage in Famagusta, North Cyprus, focusing in particular on the way in which the production was able to embellish and extend devices contained in the written text of the play to facilitate a movement from monologue to dialogue. In its conclusion, the article returns to the prevalence of monologue in Palestinian drama and to Erickson's idea that monologue involves partiality to one side of a dispute. The article contends that productions of Baggage, which, like the one in Famagusta, accentuate the dialogical, will make it clear that the play is not just a memory play for Palestinians, but that it also cries out for all those forced out of their homes and into what Edward Saïd has called ‘the trauma of exile’. Furthermore, it argues that the Traveler's monologues need to be heard and should initiate dialogues, which in some parts of the world have not yet even begun. Finally, it suggests that the universal appeal of this and other Palestinian plays could be even more striking were the heavy use of politically oriented symbolism counterbalanced by a more minimalist Beckett-like aestheticism.
Scenography and Submedial Space: Frank Castorf's Final Destination America (2000) and Forever Young (2003) at the Volksbühne Berlin
Authors: VAN DEN BERG KLAUS
Published: February 2007

German director Frank Castorf and his designer Bert Neumann have created a series of productions that have altered the dramaturgy of visual space. Their scenography integrates stage space with other spaces mediated by technology and interlocks taped and/or live mediated images with live performance. Castorf exposes spaces hidden from the audience's direct view to address the question of what ‘truth’ inheres in an image. The philosopher Boris Groys has called this spatial dramaturgy ‘submedial space’. I flesh out Groy's concept with reference to the writings of Walter Benjamin and analyse how Castorf and Neumann create such spaces through performance strategies that blend live and mediated elements. Using Castorf's productions of Final Destination America (2000) and Forever Young (2003) at the Volksbühne Berlin as examples, I argue that the multilayered images and complex spatial configurations thereby created effectively serve Castorf's purposes of political critique.
‘I Was Those Thousands!’: Memory, Identity and Space in John Kani'sNothing But the Truth
Authors: GRAHAM SHANE
Published: February 2007

John Kani'sNothing But the Truth(2002) dramatizes South Africa's collective confrontation with its traumatic past – played out on the public stage most visibly in the Truth and Reconciliation Commission (TRC) hearings – through the personal situation of Sipho Makhaya and his family. This essay analyses the obstacles Sipho and his daughter face in their attempts to negotiate new identities within the shifting social and physical geographies of post-apartheid South Africa. Identities in the apartheid era were rooted in specific places and socio-spatial configurations that are now being radically and rapidly transformed; Kani's play implies that this transitional moment in the country's history provides the opportunity to rewrite the codes that determine the ways that space is produced and used, and in the process to alter the ways that people form identities and memories in relation to both social space and other people.
Differential regulation of neuregulin 1 expression by progesterone in astrocytes and neurons
Authors: Lacroix-Fralish Michael L. , Tawfik Vivianne L. , Nutile-Mcmenemy Nancy , Harris Brent T. , Deleo Joyce A.
Published: February 2007

Glial−neuronal interactions are crucial processes in neuromodulation and synaptic plasticity. The neuregulin 1 family of growth and differentiation factors have been implicated as bidirectional signaling molecules that are involved in mediating some of these interactions. We have shown previously that neuregulin 1 expression is regulated by the gonadal hormones progesterone and 17β-estradiol in the CNS, which might represent a novel, indirect mechanism of the neuromodulatory actions of these gonadal hormones. In the present study, we sought to determine the effects of progesterone and 17β-estradiol on neuregulin 1 expression in rat cortical astrocytes and neurons in vitro. We observed that progesterone increased the expression of neuregulin 1 mRNA and protein in a dose-dependent manner in cultured astrocytes, which was blocked by the progesterone receptor antagonist RU-486. In contrast, 17β-estradiol did not increase either neuregulin 1 mRNA or protein in astrocytes. We observed no effect of either progesterone or 17β-estradiol on neuregulin 1 mRNA and protein in rat cortical neurons in vitro. Finally, we observed that treatment of cortical neurons with recombinant NRG1-β1 caused PSD-95 to localize in puncta similar to that observed following treatment with astrocyte-conditioned medium. These results demonstrate that progesterone regulates neuregulin 1 expression, principally in astrocytes. This might represent a novel mechanism of progesterone-mediated modulation of neurotransmission through the regulation of astrocyte-derived neuregulin 1.
Zuwendung – eine bedrohte Kunst der symptomatischen Therapie?
Authors: Gurtner
Published: February 2007

Einfühlende Zuwendung als unverzichtbare Grundhaltung ärztlicher Tätigkeit hat ihre Bedeutung in der technisch hocheffizienten Medizin scheinbar eingebüßt, ist aber für kranke Menschen nach wie vor hilfreich und wertvoll. Sie wird im Medizinstudium verdrängt, in der Weiterbildungszeit durch administrative Überlastung gehemmt und im späteren Erwerbsleben schlecht bezahlt, doch vertieft Zuwendung alle therapeutischen Begegnungen und schützt – richtig dosiert – vor Burnout. Einige praktische Hinweise erinnern an diese im durchrationalisierten Gesundheitswesen gefährdete berufliche Qualität.
Symptomatische Chirurgie
Authors: Huber
Published: February 2007

Wir unterscheiden zwischen symptomatischer und ätiologischer Chirurgie. Symptomatische Chirurgie umfasst Operationen, welche die Symptome einer Krankheit beseitigen, allerdings ohne die ihr zu Grunde liegende Pathologie zu beheben. Auf der anderen Seite versteht man unter ätiologischer Chirurgie die kurative Beseitigung der ursächlichen Pathologie. Man kann mit Recht sagen, dass jede Art Chirurgie symptomatisch ist, dass aber nur ein Teil von ihr ätiologisch sprich kurative Chirurgie ist. Nun existiert zusätzlich zur symptomatischen und ätiologisch-kurativen Chirurgie auch noch die prophylaktische Chirurgie. Prophylaktische Chirurgie ist ein kontroverses Thema, weil sich die Frage erhebt, ob es überhaupt eine Indikation für prophylaktische Chirurgie gäbe. Man kann nämlich sagen, dass es wohl schwierig ist durch eine Operation das Befinden eines beschwerdefreien Patienten zu bessern. Auf der anderen Seite muss man natürlich fragen, ob es nicht intelligenter sei, eine vorliegende Pathologie chirurgisch zu entfernen, bevor diese Pathologie symptomatisch wird und durch ein chirurgisches oder anderweitiges Vorgehen nicht mehr beherrscht werden kann.
Husten – wann abklären, wann behandeln?
Authors: Thurnheer
Published: February 2007

Husten ist eines der häufigsten Symptome, für welches Patienten einen Arzt aufsuchen. Der Hustenreflex schützt die Atemwege vor Aspiration und kann als diagnostisches Frühsymptom dienen. Meist wird Husten bei längerer Dauer jedoch als störend empfunden und kann die Lebensqualität erheblich beeinträchtigen. Falls möglich, sollte nach der Ursache gesucht und gezielt behandelt werden. Oft hilft jedoch erst das Ansprechen auf eine empirische Therapie, die Arbeitshypothese oder initiale Vermutung zu stützen. Die drei häufigsten behandelbaren Ursachen eines chronischen Hustens sind «Post-nasal Drip», Asthma bronchiale und gastrooesophagealer Reflux. Falls eine symptomatische oder probatorische Behandlung nicht zum Ziel führt, sind oft spezialärztliche Untersuchungen wie z.B. Bronchoprovokation, Endoskopie oder radiologische Untersuchungen zur Diagnosestellung notwendig. Bei einem produktiven Husten findet sich häufiger eine pulmonale Ursache, bei einem Reizhusten ist auch eine extrapulmonale Ursache zu suchen.
Dyspnoe – vom Verständnis des Mechanismus zur richtigen, symptomatischen Therapie
Authors: Breitenbücher
Published: February 2007

Dyspnoe ist eines der häufigsten und unangenehmsten Symptome, welches Patienten empfinden können. Mittels guter Anamnese, gründlicher Untersuchung und schrittweisem Einsatz der Hilfsuntersuchungen kann die Ursache einer Dyspnoe zu einem großen Teil bereits in der Praxis diagnostiziert werden. Die Behandlung der Dyspnoe beinhaltet selbstverständlich eine möglichst optimale Behandlung der zu Grunde liegenden Erkrankung. Leider erweist sich bei vielen Patienten die Behandlung der Grundkrankheit als nicht genügend wirksam, so dass zusätzlich eine symptomatische Therapie erforderlich ist. Dabei sollen die bei einem individuellen Patienten zu Grunde liegenden pathophysiologischen Mechanismen beachtet werden. Mögliche Ansatzpunkte sind die Verbesserung der Atemmechanik, die Verminderung einer übermäßigen Ventilation, die Verbesserung der Funktion der Atemmuskulatur und des Atemmusters, die Sauerstofftherapie sowie Maßnahmen zur Verminderung der zentralen Perzeption der Dyspnoe. Häufig ist eine Kombination mehrerer dieser Behandlungsmöglichkeiten erforderlich, um eine relevante Reduktion der Symptome zu bewirken.
Blood-flow of the inferior mesenteric and internal iliac arteries among patients undergoing open surgery for abdominal aortic aneurysm
Authors: Björck  , Bergqvist
Published: February 2007

Background: The blood-flows in the inferior mesenteric artery (IMA) and internal iliac arteries (IIAs) among patients operated on for abdominal aortic aneurysm (AAA) need to be characterized. Patients and methods: The blood-flows in the IMA and IIAs were measured with transit-time flowmeter in 26 consecutive patients who underwent open surgery for AAA. The blood-flow of the superior mesenteric artery was not studied. Results: The IMA could be measured in 25 patients, was occluded at its origin from the aorta in ten, one of whom had a collateral blood-flow of 31 ml/min distal to the occlusion. In 16 with a measurable IMA blood-flow, the median blood-flow was 26 ml/min (range 14–57 ml/min). In all 25 patients the median blood-flow in the IMA was 18 ml/min. The IIAs were occluded bilaterally in two patients and unilaterally in five. The median blood-flow in the right IIA was 111 ml/min (0–268), in the left 94 ml/min (0–340). The median blood-flow in the three studied arteries was 256 ml/min (0–506). The median proportion of the blood-flow originating from the IMA, compared to the blood-flow of all three arteries, was 10% (0–100%). One patient with no flow in any of three arteries developed colonic ischaemia. Conclusions: The relative blood-flow of the IMA, in relation to that of the IIAs, is small in most patients. In patients with IIA aneurysms or simultaneous occlusive disease, blood-flow measurements may be valuable for clinical decision-making.
Proximal deep venous thrombosis following PTA of the superficial femoral artery – an obligation to disclose a complication that is rarely taken into account
Authors: Klein-Weigel  , Pillokat  , Klemens  , Köning  , Wolbergs  , Schröder  , Wissgott  , Flessenkämper  , Steinkamp
Published: February 2007

We report two cases of femoral vein thrombosis after arterial PTA and subsequent pressure stasis. We discuss the legal consequences of these complications for information policies. Because venous thrombembolism following an arterial PTA might cause serious sequel or life threatening complications, there is a clear obligation for explicit information of the patients about this rare complication.
Superselective embolization of deep femoral artery branch pseudoaneurysm with a coaxial microcatheter system
Authors: Waldherr  , Kickuth  , Ludwig  , Do  , Triller
Published: February 2007

This report describes the use of transluminal coil embolization to treat pseudoaneurysm of deep femoral artery branch in two patients. The pseudoaneurysms had developed after coronary angiography in one patient and after hip replacement in the other. Immediate control angiography after embolization procedures demonstrated complete closure of the pseudoaneurysms. During follow-up of 19 and 3 months, respectively, there was no recurrent bleeding. The aim of this case report is to show the advances in endovascular microcatheter technology, and embolic materials, that made percutaneous transluminal embolization of arterial pseudoaneurysms safe and efficient. In addition, it keeps the medical personnel aware of vascular injuries at the access site related to endovascular procedures as well as vascular complications of total hip arthroplasty. It calls their attention to the possibility of endovascular treatment as an alternative to surgery.
The influence of downstream arterial perfusion parameters on Doppler pulsatility index and resistance index in an in-vitro perfusion model
Authors: Schmidt  , Ockert  , Deußen  , Schellong
Published: February 2007

Background: To investigate in vitro how downstream perfusion parameters influence pulsatility index (PI), resistance index (RI) and their constituting Doppler velocities. Materials and methods: We analyzed the influence of resistance, compliance, reflection coefficient and input impedance on PI and RI in an in-vitro model of arterial flow. Results: The nominators of PI and RI were determined by resistance. The numerators were determined by compliance and by the reflection coefficient. There were close relationships of PI and RI with resistance under the condition of constant compliance, but not when compliance was variable. Conclusion: PI and RI consist of velocity terms which are independently influenced by different parameters of impedance: compliance, reflection coefficient and resistance. These findings explain the contradictory results reported for the relationship between the indices and peripheral resistance in studies where compliance and reflection effects were not considered.
Endovascular repair of a traumatic popliteal arteriovenous fistula
Authors: Papavassiliou  , Dervisis  , Argitis  , Xanthopoulos  , Loupou  , Arvanitis
Published: February 2007

We report a case of an arteriovenous fistula (AVF) following osteosynthetic treatment of a fracture of the lower limb 13 years ago. A stent-graft technique had been used to close a high flow traumatic AVF between the popliteal artery and the popliteal vein. The failure to properly evaluate traumatic AVF may sometimes lead to remarkable delay in diagnosis with devastating consequences including edema, ischaemia, ulceration and high output heart failure. Endovascular treatment of these lesions is promising but long-term follow-up will be required to determine the durable patency and the onset of potential complications.
Nichtsteroidale Antirheumatika und Coxibe – die sanften Herzensbrecher?
Authors: Zellweger  , Pfisterer
Published: February 2007

Die Coxibe haben sich in den letzten Jahren sehr gut als Analgetika etabliert; dies unter anderem wegen ihrer besseren gastro-intestinalen Verträglichkeit. Ihre hoch-selektive Hemmung des Cox-2-Rezeptors ist wahrscheinlich einer der Gründe, weshalb es zu thrombotischen und kardio-vaskulären Ereignissen kommen kann. Zudem führen die Coxibe wie zum Teil die älteren nicht-steroidalen Antirheumatika (NSAR) zu einer Erhöhung des kardiovaskulären Risikoprofils. Diese Nebenwirkungen sind multifaktoriell bedingt: Wirkung auf die Thrombozytenfunktion, Gerinnung, Gefässphysiologie und Blutdruck. Mehrere Studien belegten ein erhöhtes kardiovaskuläres Risiko der Coxibe, aber auch der älteren NSAR. Wichtig für die Beurteilung dieser Studien sind die Tatsachen, dass es sich immer um niedrige Ereignisraten und in der Mehrzahl der Fälle um eine Häufung von nicht-fatalen Ereignissen bei Patienten mit bereits breitem Risikoprofil für eine kardio-vaskuläre Erkrankung handelte. Für die tägliche Praxis kann aus dieser Beobachtung der Schluss gezogen werden, dass gerade bei chronischen Schmerzen diese Analgetika nach sorgfältiger Nutzen- Nebenwirkungsanalyse weiterhin eine Therapieoption darstellen können.
Fibrothekom des Ovars: MR-Bildgebung und Differentialdiagnose
Authors: Knüsel  , Kubik-Huch  , Komminoth  , Siragusa  , Otto
Published: February 2007

Wir berichten über die präoperative Magnetresonanz(MR)-Bildgebung bei einer 70-jährigen Patientin mit grossem Unterbauchtumor. Die MRT zeigte eine sehr grosse, T2-hypointense Raumforderung im kleinen Becken, deren Ursprung entweder im linken Ovar oder im Uterus liegen musste. Die Differentialdiagnose umfasste ein grosses, subseröses, gestieltes Leiomyom oder einen zellarmen, in erster Linie benignen Tumor des Ovars. Die Histologie ergab ein benignes, nicht-hormonproduzierendes Fibrothekom des linken Ovars.
Diskusluxation: Stressbewältigung über das Kiefergelenk
Authors: Rohner
Published: February 2007

Parafunktionen wie Bruxismus und Pressen sind häufig stressbedingt und in der heutigen turbulenten Zeit vermehrt anzutreffen. In Abhängigkeit zur Zeit entwickeln diese Kräfte Schädigungen im Kiefergelenk, speziell am Discus articularis mit seinem Halteapparat. Die Diskusluxation stellt demzufolge eine häufige Erkrankung dar, welche mehrheitlich das weibliche Geschlecht betrifft. In der Mehrzahl der Fälle ist die konservative Therapie mit Physiotherapie und Muskellockerung ausreichend, um die Patienten beschwerdefrei zu machen. Eine restituto ad integrum ist auch chirurgisch nicht mehr möglich, weshalb eine operative Intervention eher zurückhaltend indiziert ist.
84-jähriger Rentner mit progredienten sensomotorischen Ausfällen
Authors: Ozimek  , Fischli  , Vetter  , Stanga  , Cottagnoud  , Stucki
Published: February 2007

Die zervikale Spinalkanalstenose ist eine Einengung des Wirbelkanals im Bereich der HWS mit konsekutiver Kompression von Rückenmark und/oder Nervenwurzeln auf einer oder mehreren Ebenen. Die klinische Symptomatik zervikaler Spinalkanalstenosen ist nicht pathognomonisch. Aufgrund der hohen Prävalenz von zervikalen Spinalkanalstenosen bei armbetonten Hyp- und Dysästhesien mit motorischen Ausfällen sowie Blasenentleerungsstörungen sollte differentialdiagnostisch immer an diese Möglichkeit gedacht werden. Idealerweise erfolgt die bildgebende Diagnostik mittels einer Magnetresonanztomographie. Therapeutisch sollte die Option einer Operation möglichst frühzeitig erwogen werden, da sich zervikale Myelopathien postoperativ meist vollständig zurückbilden.
Iron links river runoff and shelf width to phytoplankton biomass along the U.S. West Coast
Authors: Chase Zanna , Strutton Peter G. , Hales Burke
Published: February 2007

A poleward increase in phytoplankton biomass along the West Coast of North America has been attributed to increasing river runoff towards the north. We combine streamflow and shelf width data with satellite‐derived estimates of phytoplankton biomass to quantify the relationship between these variables. We find that a combination of winter streamflow and shelf width can account for over 80% of the spatial variance in summer chlorophyll within 50 km of the coast. At a given location, interannual variability in streamflow is not associated with interannual variability in chlorophyll. We attribute these relationships to the role of rivers as suppliers of the micronutrient iron, and the role of the shelf as a ‘capacitor’ for riverine iron, charging during the high‐flow winter season and discharging during the upwelling season. Data from the Oregon shelf confirm that, during winter, a significant fraction of riverine iron escapes the estuary and reaches the coastal ocean.
Estimates of atmospheric dry deposition and associated input of nutrients to Gulf of Aqaba seawater
Authors: Chen Ying , Mills Sally , Street Joseph , Golan Dorit , Post Anton , Jacobson Mark , Paytan Adina
Published: February 2007

Dry deposition rates and associated inputs of soluble inorganic nitrogen (N) phosphorus (P) and iron (Fe) were calculated for the north coast of the Gulf of Aqaba in Eilat, Israel, between August 2003 and September 2005. The main inorganic N compounds in the water soluble fraction of aerosol particles were nitrate (60%) and ammonium (38%), with mean concentrations of 35 and 22 nmol m−3 of air, respectively. Soluble phosphate ranged between 0.09 and 2 nmol m−3 of air with a mean value of 0.4 nmol m−3 of air. The soluble inorganic nitrogen and soluble phosphate account for approximately 86% and 69% of total soluble nitrogen and total soluble phosphorus, respectively; the difference is assigned to organic N and P compounds. The mean concentration of soluble aerosol Fe was 0.3 nmol m−3 of air. Our measurements of the soluble nutrient concentrations are comparable to data previously reported for the eastern Mediterranean area. Dry deposition fluxes of nutrients were estimated for each sampling date using a size‐dependent deposition model. The estimated fluxes were highly variable over the sampling period with the mean fluxes of 38, 0.2 and 0.02 μmol m−2 d−1 for seawater soluble inorganic N, P and Fe, respectively. The soluble phosphate flux shows a seasonal pattern with higher input during the winter (September to December) than in other seasons. The inorganic N/P molar ratios in the seawater‐soluble fraction of the dry deposition (ranging from 32 to 541) were well above the Redfield ratio (N/P = 16), suggesting that atmospheric inputs of nutrients increase the likelihood for P limitation in the Gulf. Atmospheric deposition could contribute a substantial fraction (35%) of dissolved inorganic N to the euphotic zone during the stratification period (April to October), and the N flux from this source could support over 10% of surface primary production and possibly all of the new production during the summer; however, these estimates have a relatively large uncertainty due to error associated with deposition flux calculation and the temporal variability in dust flux. Atmospheric input of seawater‐soluble Fe is in large excess compared to that required for the phytoplankton growth driven by the N deposition.
Hydrologic effects on methane dynamics in riparian wetlands in a temperate forest catchment
Authors: Itoh Masayuki , Ohte Nobuhito , Koba Keisuke , Katsuyama Masanori , Hayamizu Kana , Tani Makoto
Published: February 2007

To understand how hydrological processes affect biogeochemical and methane (CH4) cycles in temperate riparian wetlands, we measured CH4 fluxes and dissolved chemical constituents and CH4 concentrations in groundwater, and monitored several environmental factors in wetlands located within a forested headwater catchment in a warm, humid climate in Japan. Variation in redox components dissolved in groundwater, including nitrate (NO3−), Mn, Fe, and sulfate (SO42−), depended on temperature and soil‐water conditions. Strongly reducing conditions usually occurred in the high‐temperature months of July, August, and September. Dissolved CH4 in groundwater changed with redox conditions and was highest in summer and lowest in winter. CH4 emissions from riparian wetlands were observed almost throughout the year and displayed clear seasonality. Occasionally in summer, emission rates were more than 4 orders of magnitude greater than hillslope uptake rates. Although CH4 emissions increased markedly during most of the summer, they were constrained by (1) fluctuation of the water table, which when lowered can shift the subsurface zone to a more oxidized condition, and (2) the oxygen‐rich water such as precipitation and lateral subsurface flow from the hillslope. These results suggest that hydrological processes in forest headwater catchments play an important role in supplying oxygen to soils and consequently affect biogeochemical cycles, including CH4 formation, and that small wetlands in forest watersheds function as large sources of CH4, especially in regions with warm humid summers.
Diurnal variations of ELF transients and background noise in the Schumann resonance band
Authors: Greenberg Eran , Price Colin
Published: February 2007

Schumann resonances (SR) are resonant electromagnetic waves in the Earth‐ionosphere cavity, induced primarily by lightning discharges, with a fundamental frequency of about 8 Hz and higher‐order modes separated by approximately 6 Hz. The SR are made up of the background signal resulting from global lightning activity and extremely low frequency (ELF) transients resulting from particularly intense lightning discharges somewhere on the planet. Since transients within the Earth‐ionosphere cavity due to lightning propagate globally in the ELF range, we can monitor and study global ELF transients from a single station. Data from our Negev Desert (Israel) ELF site are collected using two horizontal magnetic induction coils and a vertical electric field ball antenna, monitored in the 5–40 Hz range with a sampling frequency of 250 Hz. In this paper we present statistics related to the probability distribution of ELF transients and background noise in the time domain and its temporal variations during the day. Our results show that the ELF signal in the time domain follows the normal distribution very well. The σ parameter exhibits three peaks at 0800, 1400, and 2000 UT, which are related to the three main global lightning activity centers in Asia, Africa, and America, respectively. Furthermore, the occurrence of intense ELF events obeys the Poisson distribution, with such intense events occurring every ∼10 s, depending on the time of the day. We found that the diurnal changes of the σ parameter are several percent of the mean, while for the number of intense events per minute, the diurnal changes are tens of percent about the mean. We also present the diurnal changes of the SR intensities in the frequency domain as observed at our station. To better understand the diurnal variability of the observations, we simulated the measured ELF background noise using space observations as input, as detected by the Optical Transient Detector (OTD). The most active center which is reflected from both ELF measurements and OTD observations is in Africa. However, the second most active center on the basis of ELF measurements appears to be Asia, while OTD observations show that the American center is more active than the Asian center. These differences are discussed. This paper contributes to our understanding of the origin of the SR by comparing different lightning data sets: background electromagnetic radiation and optical emission observed from space.
Polarity asymmetry of sprite‐producing lightning: A paradox?
Authors: Williams E. , Downes E. , Boldi R. , Lyons W. , Heckman S.
Published: February 2007

Sprites and halos in the mesosphere are produced electrostatically by lightning ground flashes whose polarity is positive, by a margin of at least 1000 to 1 in collected observations. The initiation of these events is controlled by the vertical charge moment change of the flash. Schumann resonance ELF methods have been used to measure the charge moments of millions of flashes worldwide. The bipolar distributions of these events show stronger positive than negative tails, consistent with the predominance of “positive” sprites, but the negative tail of supercritical events is still of the order of 10% of the total supercritical population, more than 1 order of magnitude larger than the observed fraction of “negative” sprites. This juxtaposition constitutes a paradox. The suggested resolution of the paradox is that the more impulsive population of supercritical negative flashes is producing dim halos that are not readily detected in conventional video imagery. Additional sensitive, high‐resolution, and high‐speed imager (<1 ms) studies of halos and their lightning parents are needed to verify this hypothesis.