Management options for restoring estuarine dynamics and implications for ecosystems: a quantitative approach for the Southwest Delta in the Netherlands

The Delta Works, a series of dams and barriers constructed in the 1960's–1980's changed the estuarine landscape of the Rhine-Meuse-Scheldt delta (SW Netherlands) into more stagnant and disengaged freshwater, brackish water or saltwater lakes. The remaining tidal systems were adapted by building a storm surge barrier in the Oosterschelde and dike reinforcement works along the Westerschelde. The Delta Works brought protection against flooding, but at the same time resulted in environmental and socio-economic problems, such as degradation of ecological quality and ecosystem functioning, disruption of fish migration routes, water and sediment quality problems.In this study we explore in an integrated, quantitative way the consequences of a number of management options for the Southwest Delta and their implications for the occurrence and distribution of aquatic and estuarine habitats, considering the mutual coherence between the water basins. Five scenarios were evaluated using a 1D hydraulic, water quality and primary production numerical model and GIS habitat mapping. Scenarios vary from small-scale interventions, such as changes in day-to-day management of hydraulic infrastructures or creation of small inlets in dams, feasible in the short term, to restoration of an open delta by removing dams and barriers, as a long term potential. We evaluate the outcomes in relation to the restoration of estuarine dynamics, as this is in policy plans proposed as a generic solution for the current ecological and environmental problems. Net water flow rates show more complex patterns when connectivity between water basins is increased and when sluice management is less strict. Estuarine transition zones and fish migration routes are partly restored, but only fully develop when basins are in open connection with each other. Area of intertidal habitats, tidal flats and tidal marshes, increases in each scenario, ranging between 7 and 83%, 1–56%, and 8–100% respectively, depending on scenario. Large scale infrastructural adaptations are needed to restore estuarine dynamics at large scale.The use of a 1D numerical model allowed to quantify the effect of different management measures for all water basins simultaneously, but also has its limitations. The model does not resolve more complex processes such as vertical mixing and morphodynamic changes. This requires expert judgment and more detailed 3D modelling

The prognosis of oncologic patients in the pediatric intensive care unit

Objective: To evaluate the predicted mortality rate of oncologic patients in the PICU using the PRISM score and factors that might influence short-term outcomes. Design: Retrospective study. Setting: Pedriatic ICU in a university hospital. Patients and Methods: The medical charts of all oncologic patients admitted to the PICU during the period from January 1983 to December 1992 were reviewed. Main Results: Over a period of 10 years, 51 oncologic patients were admitted on 57 occasions to the PICU. The mortality was 32%. This is significantly higher than the overall mortality in the PICU (8%). Comparison of observed and predicted mortality, derived from the PRISM score, using chi square goodness-of-fit tests showed a significantly higher observed mortality (χ2(5) = 20.1, P < 0.01). Patients admitted for circulatory failure had the highest mortality (47%), followed by those with respiratory failure due to tachypnea/cyanosis (36%), central nervous system deterioration (27%), respiratory failure due to airway obstruction (25%), and metabolic disorders (20%). Of the 31 patients who needed mechanical ventilation, 17 died (55%), and when they needed inotropic support as well, the mortality increased to 69%. The mortality rose to 100% when the patient was admitted with a septic shock, necessitating mechanical ventilation and inotropic support. The median PRISM score was 5 in the survivor group and 18.5 in the non-survivor group; this difference was found to be significant using the Wilcoxon test (P = 0.01). However, some patients with high scores were found in the survivor group, as well as some with low scores in the non-survivor group. Conclusion: The decision to treat oncologic patients in a PICU remains difficult and has to be considered on an individual basis. However, oncologic patients do benefit from admission to the PICU. The PRISM score is not suitable for oncologic patients in the PICU, because it underestimates the observed mortality. Other factors like neutropenia, septic shock, the need for mechanical ventilation, and inotropic support should be taken into consideration

Ambulatory Estimation of Relative Foot Positions using Ultrasound

The recording of human movement is used for biomedical applications like physical therapy and sports training. Over the last few years inertial sensors have been proven to be a useful ambulatory alternative to traditional optical systems. An example of a successful application is the instrumented shoe, which contains two 6D force/moment sensors beneath the heel and the forefoot and two inertial sensors rigidly attached to the force/moment sensors [1]. These shoes can be used for ambulatory assessment of walking kinetics and kinematics. The relative position of the feet is currently not measured directly but estimated from double integration of feet accelerations. However, this method immediately leads to large position errors (drift) when the estimated inertial accelerations are inaccurate. In this study we investigated the ambulatory estimation of the relative positions of the feet using ultrasound transducers. On one shoe we mounted a 400PT120 Air Ultrasonic Ceramic Transducer (13 mm diameter, 10 mm height, 85º beam angle) sending a 40 kHz pulse to a similar transducer on the other shoe. Using the time of flight, the distance is estimated. Under static conditions a mean error of 5.7 ±0.8 mm was obtained over a range of 5 till 75 cm [2]. From this pilot study we concluded that the distance between the feet can be estimated ambulatory using small and low-cost ultrasound transducers. Future research includes the use of multiple transducers on each foot for a distance measure during different daily-life activities. Also the relative positions of the feet will be investigated by fusing the distance estimates with inertial sensor data

Рівняння електромагнітної механіки пористого насиченого середовища

За двоконтинуумного наближення отримано повну систему співвідношень моделі електромагнітомеханіки статистично однорідного та ізотропного пористого насиченого середовища. Враховано наявність подвійного електричного шару в околі межі контакту твердої і рідкої фаз.Complete set of the model equations for electromagnetic mechanics of the porous saturated medium being statistically homogeneous and isotropic is obtained in two-continuum approximation. The presence of a double electrical layer in an environ of contact boundary of solid and liquid phases is taken into account.В двухконтинуумном приближении получено полную систему соотношений модели электромагнитомеханики статистически однородной и изотропной пористой насыщенной среды. Учтено наличие двойного электрического слоя в окрестности границы контакта твердой и жидкой фаз

On-line Excited-State Laser Spectroscopy of Trapped Short-Lived Ra+^+ Ions

As an important step towards an atomic parity violation experiment in one single trapped Ra$^+$ ion, laser spectroscopy experiments were performed with on-line produced short-lived $^{212,213,214}$Ra$^+$ ions. The isotope shift of the 6\,^2D$_{3/2}$\,-\,7\,^2P$_{1/2}$ and 6\,^2D$_{3/2}$\,-\,7\,^2P$_{3/2}$ transitions and the hyperfine structure constant of the 7\,^2S$_{1/2}$ and 6\,^2D$_{3/2}$ states in $^{213}$Ra$^+$ were measured. These values provide a benchmark for the required atomic theory. A lower limit of $232(4)$ ms for the lifetime of the metastable 6\,^2D$_{5/2}$ state was measured by optical shelving.Comment: 4.2 pages, 6 figures, 2 tables

Self-poisoning in rural Sri Lanka: small-area variations in incidence

<p>Abstract</p> <p>Background</p> <p>Self-poisoning is one of the most common methods of suicide worldwide. The intentional ingestion of pesticides is the main contributor to such deaths and in many parts of rural Asia pesticide self-poisoning is a major public health problem. To inform the development of preventive measures in these settings, this study investigates small-area variation in self-poisoning incidence and its association with area-based socioeconomic and agricultural factors.</p> <p>Methods</p> <p>Ecological analysis of intentional self-poisoning in a rural area (population 267,613) of Sri Lanka in 2002. The geographic distribution of cases was mapped to place of residence. Using administrative division (GN), median population size 1416, as unit of analysis, associations with socioeconomic and agricultural indicators were explored using negative binomial regression models.</p> <p>Results</p> <p>The overall incidence of intentional self-poisoning in the study area was 315 per 100,000 (range: 0 – 2168 per 100,000 across GNs). Socioeconomic disadvantage, as indexed by poor housing quality (p = 0.003) and low levels of education (p < 0.001) but not unemployment (p = 0.147), was associated with a low self-poisoning incidence. Areas where a high proportion of the population worked in agriculture had low overall levels of self-poisoning (p = 0.002), but a greater proportion of episodes in these areas involved pesticides (p = 0.01). An association with extent of cultivated land was found only for non-pesticide poisoning (p = 0.01).</p> <p>Conclusion</p> <p>Considerable small-area variation in incidence rates of intentional self-poisoning was found. The noteworthy concentration of cases in certain areas and the inverse association with socioeconomic deprivation merit attention and should be investigated using individual-level exposure data.</p

Low Surface Brightness Galaxies around the HDF-S: II. Distances and volume densities

With this study we aim at the spectroscopic verification of a photometrically selected sample of Low Surface Brightness (LSB) galaxy candidates in a field around the Hubble Deep Field-South (HDF-S). The sample helps to extend the parameter space for LSB galaxies to lower central surface brightnesses and to provide better estimates on the volume densities of these objects. To derive redshifts for the LSB candidates, long-slit spectra were obtained covering a spectral range from 3400{\AA} to 7500{\AA}. The observations have been obtained using the ESO 3.6m telescope, equipped with the EFOSC2 spectrograph. From the measured radial velocities, distances could be estimated. With this distance information, it is possible to differentiate between true LSB galaxies and higher redshift High Surface Brightness (HSB) galaxies which may contaminate the sample. A correction for the surface brightnesses can then be applied, accounting for the cosmological dimming effect (``Tolman Dimming''). We show that ~70% of the LSB candidates, selected based on their location in the color-color space, are real LSB galaxies. Their position in the color-color diagrams, therefore, indicate that the LSB galaxies have a different stellar population mix resulting from a different star formation history compared to HSBs. Our LSB galaxy sample consists only of large disk galaxies with scale-length between 2.5kpc and 7.3kpc. We confirm the flat central surface brightness distribution of previous surveys and extend this distribution down to central surface brightnesses of 27 B mag arcsec^-2.Comment: 12 pages, 20 figures, accepted by A&