Hydropeaking is one of the main pressures on the aquatic ecology in alpine rivers. Beside studies on abiotic process and biotic response on the local scale there is a lack in process understanding on ...the reach scale. Especially longitudinal changes of hydropeaking impacts based on retention processes have not been studied yet. Thus, based on unsteady one-dimensional and two-dimensional depth averaged modelling it was targeted to investigate possible changes in vertical ramping velocity for the discussion of possible mitigation measures at the local scale. Here, we compared artificial and natural sheltering habitats in terms of peak flow. Additionally, the hydropeaking assessment on various river scales was supported by an evaluation of tributaries in an alpine river system. Based on the modelling results and the discussion of the impact assessment of hydropeaking in different case studies we state, that on the first 5km downstream of the turbine outlet a significant decrease in vertical ramping velocity occurs. In this reach, habitat improvements should focus on increasing retention processes considering the higher risk of stranding for juvenile fish and macroinvertebrates. For morphological mitigation measures at the local scale, it turned out that self-formed, near-natural morphology should be targeted in terms of mitigation measure design compared to artificial sheltering habitats. Abundance and biomass of macroinvertebrates are directly linked to substrate variability in self-formed sheltering habitats downstream of gravel bars. Moreover, we ascertained that tributaries are able to contribute to the ‘ecological potential’ in multi-stressed hydropeaking rivers by providing spawning and rearing habitats for fish. However, for a sustainable improvement of the aquatic environment on all relevant scales, both sediment and flood dynamics have to be considered as important drivers to establish self-formed sheltering habitats in terms of hydropeaking.
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•Peak flow retention leads to a significant decrease in vertical ramping velocities at the first five kilometres downstream of the turbine outlet•Analysis of peak flow retention and thresholds for stranding of fish and macroinvertebrates allows a pre-liminary assessment for mitigation•For morphological mitigation measures self-formed, near natural morphology should be targeted•The connectivity to tributary systems with a natural flow and sediment regime is important for spawning and rearing of target fish species
Two factors complicate the ecological status classification of very large rivers in Europe according to the EU Water Framework Directive: First, current assessment methods do not fully consider the ...specific ecology of very large rivers (such as lateral connectivity and the role of floodplains for ecological status). Second, most of Europe's very large rivers have been severely altered by human activities such as flood protection, damming and navigation. The aim of our study is to develop an assessment method for very large rivers by identifying suitable biological metrics as the basis for multi-metric bioassessment using benthic invertebrates. Based on the pan-European typology of very large rivers by Borgwardt et al. (2019), we established a river type-specific assessment approach using invertebrate samples from 25 European countries and 94 very large rivers. The frequency and intensity of eight pressures jointly acting on the sampling sites were described, and a selection of suitable invertebrate community metrics were correlated with the pressure intensities to establish pressure-response relationships. The very large river types differ in terms of relevant pressures and pressure combinations, with the invertebrate communities distinctly responding to these pressure patterns. Neozoa dominance correlated strongly with ‘navigation’, being a major pressure at very large rivers, which entails severe hydro-morphological alterations such as channelization, riparian vegetation alteration and impoundment. Under combined pressures, a critical community turnover became evident in terms of neozoa outnumbering EPT taxa and the ratio of hemilimnic invertebrates decreasing. We propose ten bioassessment metrics, including measures of biological diversity as well as newly generated indicators, for the development of a European type-specific assessment method for very large rivers.
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•We analysed 1197 invertebrate samples from 94 very large European rivers.•Commonly used and newly generated metrics were correlated with eight stressors.•Navigation was allocated as the ‘super-stressor’ strongly correlating with neozoa.•We assigned between two and eight core metrics to the seven very large river types.•The study provides a basis for future multi-metric bioassessment systems.
Aberrations in optical microscopy reduce image resolution and contrast, and can limit imaging depth when focusing into biological samples. Static correction of aberrations may be achieved through ...appropriate lens design, but this approach does not offer the flexibility of simultaneously correcting aberrations for all imaging depths, nor the adaptability to correct for sample-specific aberrations for high-quality tomographic optical imaging. Incorporation of adaptive optics (AO) methods have demonstrated considerable improvement in optical image contrast and resolution in noninterferometric microscopy techniques, as well as in optical coherence tomography. Here we present a method to correct aberrations in a tomogram rather than the beam of a broadband optical interferometry system. Based on Fourier optics principles, we correct aberrations of a virtual pupil using Zernike polynomials. When used in conjunction with the computed imaging method interferometric synthetic aperture microscopy, this computational AO enables object reconstruction (within the single scattering limit) with ideal focal-plane resolution at all depths. Tomographic reconstructions of tissue phantoms containing subresolution titanium-dioxide particles and of ex vivo rat lung tissue demonstrate aberration correction in datasets acquired with a highly astigmatic illumination beam. These results also demonstrate that imaging with an aberrated astigmatic beam provides the advantage of a more uniform depth-dependent signal compared to imaging with a standard Gaussian beam. With further work, computational AO could enable the replacement of complicated and expensive optical hardware components with algorithms implemented on a standard desktop computer, making high-resolution 3D interferometric tomography accessible to a wider group of users and nonspecialists.
Artificial flow fluctuations due to the operation of hydropower plants, frequently described as hydropeaking, result in a constant decrease of biomass of specific macrozoobenthos (MZB) taxa. For the ...presented case study, we assessed three reaches in the Ziller River catchment. At each sampling reach we performed the Multi-Habitat-Sampling (MHS) method with a Water Framework Directive (WFD) compliant AQEM/MHS net according to the Austrian guideline. Additionally, a hydraulic-specific sampling was conducted with a modified Box (Surber) sampler. As a basis for predictive habitat modelling of the MZB fauna, we measured abiotic parameters like mean (v40) and bottom-near (vbottom) flow rate or water depth respectively, for each box sample. In addition, the choriotope type, representing grain size classes, was determined. One of the main results is, that the national status assessment was not capable to reflect the impact of pulse release at the investigated river stretches on the basis of status classes. Moreover, we figured out that 1) habitats of stagnophilic macroinvertebrate taxa are minimized in channelized stretches affected by hydropeaking, leading to heavy quantitative losses for populations, becoming apparent in significant decreases in total individual numbers and biomass for many taxa. 2) The minor respond of the ecological status class in affected stretches by applying the WFD compliant national assessment method for macroinvertebrates owes to the tolerance of rheobiont or rheophilic taxa commonly classified as indicators for good conditions regarding saprobity or degradation score. 3) A development of a stressor-specific sampling design is required as the MHS method largely ignores vulnerable habitats. 4) The habitat suitability of selected species provides efficient expertise for impact assessment and mitigation measure design in terms of predictive habitat modelling.
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•Habitats of stagnophilic macroinvertebrate taxa are significantly minimized in channelized stretches affected by hydropeaking.•The WFD compliant national Austrian assessment method fails to detect impacts of hydropeaking on macroinvertebrates.•The development of a stressor-specific sampling design is required as the MHS largely ignores vulnerable habitats.•The hydraulic stress analysis provides expertise on the resistance of certain taxa in terms of hydropeaking.
Using retrograde transneuronal transfer of rabies virus in combination with a conventional tracer (cholera toxin B), we studied simultaneously direct (thalamocortical) and polysynaptic inputs to the ...ventral lateral intraparietal area (LIPv) and the medial intraparietal area (MIP) in nonhuman primates. We found that these areas receive major disynaptic inputs from specific portions of the cerebellar nuclei, the ventral dentate (D), and ventrolateral interpositus posterior (IP). Area LIPv receives inputs from oculomotor domains of the caudal D and IP. Area MIP is the target of projections from the ventral D (mainly middle third), and gaze- and arm-related domains of IP involved in reaching and arm/eye/head coordination. We also showed that cerebellar cortical “output channels” to MIP predominantly stem from posterior cerebellar areas (paramedian lobe/Crus II posterior, dorsal paraflocculus) that have the required connectivity for adaptive control of visual and proprioceptive guidance of reaching, arm/eye/head coordination, and prism adaptation. These findings provide important insight about the interplay between the posterior parietal cortex and the cerebellum regarding visuospatial adaptation mechanisms and visual and proprioceptive guidance of movement. They also have potential implications for clinical approaches to optic ataxia and neglect rehabilitation.
Abstract Background First-line treatment of isolated resectable colorectal peritoneal metastases remains unclear. This study (the Swedish peritoneal study) compares cytoreductive surgery and ...intraperitoneal chemotherapy (surgery arm) with systemic chemotherapy (chemotherapy arm). Methods Patients deemed resectable preoperatively were randomised to surgery and intraperitoneal 5-fluorouracil 550 mg/m2 /d for 6 d with repeated courses every month or to systemic oxaliplatin and 5-fluorouracil regimen every second week. Both treatments continued for 6 months. Primary end-point was overall survival (OS) and secondary end-points were progression-free survival (PFS), and morbidity. Results The study terminated prematurely when 48 eligible patients (24/arm) were included due to recruitment difficulties. Two-year OS was 54% in the surgery arm and 38% in the chemotherapy arm ( p = 0.04). After 5 years, 8 versus 1 patient were alive, respectively ( p = 0.02). Median OS was 25 months versus 18 months, respectively, hazard ratio 0.51 (95% confidence interval: 0.27–0.96, p = 0.04). PFS in the surgery arm was 12 months versus 11 months in the chemotherapy arm ( p = 0.16) with 17% versus 0% 5-year PFS. Grade III–IV morbidity was seen in 42% and 50% of the patients, respectively. No mortalities. Conclusions Cytoreductive surgery with intraperitoneal chemotherapy may be superior to systemic oxaliplatin-based treatment of colorectal cancer with resectable isolated peritoneal metastases.( ClinicalTrials.gov nr: NCT01524094 ).
Hydropeaking as a result of peak-load electricity production has been identified as one of the most significant pressures in alpine streams. Scouring of macroinvertebrates leads to downstream ...transport of aquatic organisms (catastrophic drift). Additionally, invertebrates are affected by periodic drying of wetted area during the dewatering of gravel bars and exposed areas along the banks. Even though fish are physiologically better adapted to switch to suitable habitats, artificial flow fluctuations may be followed by lethal stranding and quick alteration in habitat quantity and quality. Nevertheless, the interactions between pressures on fish and macroinvertebrates in terms of hydropeaking have not been investigated so far. The aim of this paper is to evaluate effects of flow fluctuations on potential epibenthic feeding grounds. Therefore, we evaluated changes in habitat distribution resulting from rapid flow fluctuations in river reaches with different river morphological characteristics, for five different macroinvertebrate taxa. Additionally, microhabitats for brown trout at two different life stages were calculated using representative peaking events (seasonal analysis) based on mid- to long term times series. Moreover, GIS-analysis allowed the evaluation of hydropeaking impacts (interaction) on both, macroinvertebrates and fish. In this study, it could be documented that feeding from the benthos for juvenile and subadult brown trout is inhibited during peak flow and is therefore reduced to times of base flow. Moreover, potential benthic feeding areas occurring at base flow have been found to increase with the level of morphological heterogeneity within analyzed river reaches. Likewise, hydrological sensitivity testing in terms of reducing ∆Q at different levels was performed and revealed that possible positive effects required heterogeneous river morphology as a precondition. However, this approach might be applied for estimating the impacts of hydrological mitigation measures in hydropeaked rivers concerning physical condition and/or growth rate of salmonids considering the river morphology of the investigated stream.
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•Development of a novel approach in predictive habitat modelling.•Evaluation of flow fluctuations on potential epibenthic feeding grounds.•The potential for benthic feeding in hydropeaked rivers is most convenient during base flow conditions.•Potential benthic feeding areas occurring at base flow increased with the level of morphological heterogeneity.
The impact of intraoperative fluid management during cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) on postoperative outcomes has been poorly investigated. This ...study aimed to retrospectively evaluate the impact of intraoperative fluid management strategy on postoperative outcomes and survival.
509 patients undergoing CRS and HIPEC at Uppsala University Hospital/Sweden 2004–2017 were categorized into two groups according to the intraoperative fluid management strategy: pre-goal directed therapy (pre-GDT) and goal directed therapy (GDT), where a hemodynamic monitor (CardioQ or FloTrac/Vigileo) was used to optimize fluid management. Impact on morbidity, postoperative hemorrhage, length-of-stay and survival was analyzed.
The pre-GDT group received higher fluid volume compared to the GDT group (mean 19.9 vs. 16.2 ml/kg/h, p < 0.001). Overall postoperative morbidity Grade III-V was higher in the GDT group (30% vs. 22%, p = 0.03). Multivariable adjusted odds ratio (OR) for Grade III-V morbidity was 1.80 (95%CI 1.10–3.10, p = 0.02) in the GDT group. Numerically, more cases of postoperative hemorrhage were found in the GDT group (9% vs. 5%, p = 0.09), but no correlation was observed in the multivariable analysis 1.37 (95%CI 0.64–2.95, p = 0.40). An oxaliplatin regimen was a significant risk factor for postoperative hemorrhage (p = 0.03). Mean length of stay was shorter in the GDT group (17 vs. 26 days, p < 0.0001). Survival did not differ between the groups.
While GDT increased the risk for postoperative morbidity, it was associated with shortened hospital stay. Intraoperative fluid management during CRS and HIPEC did not affect the postoperative risk for hemorrhage, while the use of an oxaliplatin regimen did.
Synopsis: A cohort study to analyze the impact of intraoperative fluid management on postoperative outcome parameters.
Abstract Background Cytoreductive surgery (CRS) and intraperitoneal chemotherapy (IPC) treatment of colorectal peritoneal carcinomatosis (PC) is gaining acceptance, but controversy remains. The ...primary aims were to analyse the outcome and prognostic variables of colorectal PC patients treated with CRS and IPC, and to report on the outcome of additional surgical treatments of subsequent recurrences. Methods Patients referred for treatment of colorectal PC between 1996 and 2010 were included in a cohort. The following data was collected: clinicopathological parameters, survival, recurrences, perioperative chemotherapy and type of IPC (hyperthermic intraperitoneal chemotherapy, HIPEC; or sequential postoperative intraperitoneal chemotherapy, SPIC). Multivariable analyses were conducted on potential prognostic factors for overall survival (OS). Results In the 151-patient cohort, the median OS was 34 months (range: 2–77) for CRS and HIPEC with five-year survival predicted at 40% (five-year disease-free survival 32%). For CRS and SPIC, the OS was 25 months (range: 2–188) with five-year survival at 18%. Open-and-close patients survived 6 months (range: 0–14) with no five-year survival (HIPEC vs. SPIC p = 0.047, SPIC vs. open-and-close p < 0.001). Adjuvant systemic chemotherapy was a noteworthy independent prognostic factor in the multivariable analysis. OS for patients undergoing additional surgical treatment of recurrences was 25 months vs. 10 months with best supportive care or palliative chemotherapy ( p = 0.01). Conclusion Substantial long-term survival is possible in patients with colorectal PC. HIPEC was associated with better OS than SPIC and adjuvant systemic chemotherapy may improve the outcome in patients. Good OS is achievable in selected patients undergoing additional surgical treatment of isolated liver or peritoneal recurrences after prior complete CRS.
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