Relevant Scales in Zooplankton Ecology: Distribution, Feeding, and Reproduction of the Copepod Acartia Hudsonica in Response to Thin Layers of the Diatom Skeletonema Costatum

We investigated the interaction of the copepod Acartia hudsonica in relation to thin layers of the diatom Skeletonema costatum. Thin layers have recently received much attention, since they are common and persistent features in the water column, often overlooked by traditional sampling methods. Their frequent abundance in coastal oceans and the high biomass associated with them has led to the assumption that they are important grazing sites of calanoid copepods. We employed 2-m tall tower tanks that allowed us to simulate thin layers. Three variables representative of three time scales were considered: the distribution of copepods in the tanks (time scale of minutes), fecal pellet production as a proxy for ingestion rate (time scale of hours), and egg production rate (time scale of \u3e12 h). A. hudsonica responded significantly but very little to the thin layers in terms of their distribution. Given a choice, there was a slightly higher tendency to swim through a patch of diatoms than to swim around it. Fecal pellet production was slightly lower in the thin-layer treatments than in the homogeneous controls. Egg production was not influenced by differential distribution of diatoms in the tanks, which indicated that the copepods dealt equally well with patchy food as when the same numbers of cells were available in a homogeneous distribution. Time series experiments showed that ingested carbon is integrated over time scales of \u3e12 h. Therefore, small-scale fluctuations of food in space and time do not necessarily translate into small-scale fluctuations in reproductive output

Approach to endoscopic extraperitoneal radical prostatectomy (EERPE): the impact of previous laparoscopic experience on the learning curve

BACKGROUND: We report our approach regarding the technique of endoscopic extraperitoneal radical prostatectomy (EERPE) and analyze the learning curve of two surgeons after thorough technical training under expert monitoring. The purpose of this study was to investigate the influence of expert monitoring on the surgical outcome and whether previous laparoscopic experience influences the surgeon's learning curve. METHODS: EERPE was performed on 120 consecutive patients by two surgeons with different experience in laparoscopy. An analysis and comparison of their learning curve was made. RESULTS: Median operation time: 200 (110-415) minutes. Complications: no conversion, blood transfusion (1.7%), rectal injury (3.3%). Median catheterisation time: 6 (5-45) days. Histopathological data: 55% pT2, 45% pT3 with a positive surgical margin rate of 6.1% and 46%, respectively. After 12 months, 78% of the patients were continent, 22% used 1 or more pad. Potency rate with or without PDE-5-inhibitors was 66% with bilateral and 31% with unilateral nerve-sparing, respectively. Operation time was the only parameter to differ significantly between the two surgeons. CONCLUSION: EERPE can be learned within a short teaching phase. Previous laparoscopic experience is reflected by shorter operation times, not by lower complication rates or superior early oncological data

Vertical distribution and diel patterns of zooplankton abundance and biomass at Conch Reef, Florida Keys (USA)

Zooplankton play an important role in the trophic dynamics of coral reef ecosystems. Detailed vertical and temporal distribution and biomass of zooplankton were evaluated at four heights off the bottom and at six times throughout the diel cycle over a coral reef in the Florida Keys (USA). Zooplankton abundance averaged 4396 ± 1949 SD individuals m−3, but temporal and spatial distributions varied for individual zooplankton taxa by time of day and by height off the bottom. Copepods comprised 93–96% of the abundance in the samples. Taxon-based zooplankton CHN values paired with abundance data were used to estimate biomass. Average daily biomass ranged from 3.1 to 21.4 mg C m−3 and differed by both height off the bottom and by time of day. While copepods were the numerically dominant organisms, their contribution to biomass was only 35% of the total zooplankton biomass. Our findings provide important support for the new emerging paradigm of how zooplankton are distributed over reefs

Managing contested spaces: Public managers, obscured mechanisms and the legacy of the past in Northern Ireland

Societies emerging from ethno-political and inter-communal conflict face a range of complex problems that stem directly from the recent lived experience of bloodshed and injury, militarisation, securitisation and segregation. As institutional agents in such an environment, public managers perform the dual role of both interpreting public policy and implementing it within a politically contested space and place. In this article we address how managers cope with the outworking of ethno-nationalist conflict and peace building within government processes and policy implementation and contend this is a subject of emerging concern within the wider public administration, urban studies and conflict literature. Using data from a witness seminar initiative on the Northern Ireland conflict transformation experience, we explain how public sector managers make sense of their role in post-agreement public management and highlight the importance of three identified mechanisms; ‘bricolage’, ‘diffusion’ and ‘translation’ in the management of public sector organisations and urban spaces in a context of entrenched conflict and an uncertain path to peace

Learning from Jerusalem: Rethinking urban conflicts in the 21st century Introduction

Jerusalem - its past, present and future - will serve as the foundation of our understanding of the geographies of cities within contemporary urban theory and practice in the 21st century. The underlying theoretical supposition in this special feature1 is that what have been labelled con- tested cities have growing similarities to less polarized cities similarities found in the expansion of ethnic, racial and class conflicts that revolve around issues of housing, infrastructure, participation and identity. In this sense, Jerusalem represents a rather exceptional case study and demonstrates a powerful spatio-political urban pattern in the field of urban studies. The examination of Jerusalem can advance our understanding of the relationship between planning conflicts and urban geopolitics in a growing number of cities worldwide

Beyond incommensurability: Jerusalem and Stockholm from an ordinary cities perspective

This paper’s core argument is that we should start creating theories that encompass different cities and include them in a more flexible and relational comparative framework. This must include a new urban terminology which does not continue the all-too-fashionable labelling of cities on a continuum between first world and third world, global North-West and South-East or as I emphasize below, including what have been labelled extremely contested cities in a more flexible and relational ordinary cities framework. To introduce such a comparative approach, I will examine Jerusalem and Stockholm via three contrastive and relational patterns: institutional segregation; urban violence; and non-governmental organization involvement in planning. In so doing, I point towards the necessity to open up research on extreme urban conflicts, suggesting that when assessing specific contextual patterns, those labelled as extremely contested cities (such as Jerusalem) share more similarities with other more ordinary cities (represented by Stockholm) than was previously perceived, often stemming from ethnic, racial and class conflicts revolving around issues of politics, culture and identity, among others

Effect of sampling effort and sampling frequency on the composition of the planktonic crustacean assemblage: a case study of the river Danube

Although numerous studies have focused on the seasonal dynamics of riverine zooplankton, little is known about its short-term variation. In order to examine the effects of sampling frequency and sampling effort, microcrustacean samples were collected at daily intervals between 13 June and 21 July of 2007 in a parapotamal side arm of the river Danube, Hungary. Samples were also taken at biweekly intervals from November 2006 to May 2008. After presenting the community dynamics, the effect of sampling effort was evaluated with two different methods; the minimal sample size was also estimated. We introduced a single index (potential dynamic information loss; to determine the potential loss of information when sampling frequency is reduced. The formula was calculated for the total abundance, densities of the dominant taxa, adult/larva ratios of copepods and for two different diversity measures. Results suggest that abundances may experience notable fluctuations even within 1 week, as do diversities and adult/larva ratios

Fractal analyses reveal independent complexity and predictability of gait

Locomotion is a natural task that has been assessed for decades and used as a proxy to highlight impairments of various origins. So far, most studies adopted classical linear analyses of spatio-temporal gait parameters. Here, we use more advanced, yet not less practical, non-linear techniques to analyse gait time series of healthy subjects. We aimed at finding more sensitive indexes related to spatio-temporal gait parameters than those previously used, with the hope to better identify abnormal locomotion. We analysed large-scale stride interval time series and mean step width in 34 participants while altering walking direction (forward vs. backward walking) and with or without galvanic vestibular stimulation. The Hurst exponent α and the Minkowski fractal dimension D were computed and interpreted as indexes expressing predictability and complexity of stride interval time series, respectively. These holistic indexes can easily be interpreted in the framework of optimal movement complexity. We show that α and D accurately capture stride interval changes in function of the experimental condition. Walking forward exhibited maximal complexity (D) and hence, adaptability. In contrast, walking backward and/or stimulation of the vestibular system decreased D. Furthermore, walking backward increased predictability (α) through a more stereotyped pattern of the stride interval and galvanic vestibular stimulation reduced predictability. The present study demonstrates the complementary power of the Hurst exponent and the fractal dimension to improve walking classification. Our developments may have immediate applications in rehabilitation, diagnosis, and classification procedures