Deploy diverse renewables to save tropical rivers.

A strategic mix of solar, wind and storage technologies around river basins would be safer and cheaper than building large dams, argue Rafael J. P. Schmitt, Noah Kittner and colleagues

The Flushing Flow Problem: Defining and Evaluating Objectives

Reservoir releases may be specified for the purpose of maintaining or improving the downstream channel and habitat. A wide variety of ecological or management objectives may be defined for such flushing flows (which may be broadly divided into sediment maintenance and channel maintenance flows). To specify a particular discharge and water volume for a flushing flow requires that the ecological or management objectives be translated into specific physical objectives for which flows can be specified. Flushing objectives that cannot be translated into definable flows are of little practical use, regardless of their intrinsic importance. Once defined, flushing flow objectives may be shown to conflict in some cases. For example, no flushing flow can satisfy the typical sediment maintenance objectives of maximizing sand removal and minimizing gravel loss. A discharge that mobilizes sediment throughout the channel cross section for channel maintenance purposes will often produce comparable transport rates of sand and gravel, thereby eliminating the selective transport of sand needed to reduce the sand content in the bed. Some nonflushing alternatives, such as artificial gravel replenishment and pool dredging, can be used to improve the performance of flushing flows. Selection among these alternatives and specification of a flushing flow discharge and volume depend directly on quantitative estimates of sand and gravel transport as a function of flow rate and volume

Sediment Starvation from Dams in the Lower Mekong River Basin: Magnitude of the Effect and Potential Mitigation Opportunities

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchive

River research and applications across borders

Rivers flow across national borders, unfettered by political distinctions, and the ecological health of rivers is closely linked to their degree of connectivity. River research today is more global than it has ever been, but we show that river research, engineering, and management still operate within homegrown local paradigms. As a basis for this discussion, we studied the citation networks surrounding the most widely cited papers in our field, assessing the degree to which researchers have collaborated across geographical boundaries and fully drawn from the international literature. Despite gains over time, our field remains surprisingly and pervasively provincial. The likely explanation for provincial bias is that researchers are generally more familiar and comfortable with their own research methods, sites, and agendas. However, local focus has tangible consequences. For example, contrasting paradigms and differing approaches to river restoration and to flood-risk management show that opportunities are lost when we fail to learn from the successes and failures of other regions. As Sharp and Leshner (2014; p. 579) have argued, "the search for solutions needs to draw upon the talents and innovative ideas of scientists, engineers, and societal leaders worldwide to overcome traditional and nationalistic paradigms that have so far been inadequate to meeting these challenges.

Biomic river restoration: A new focus for river management

River management based solely on physical science has proven to be unsustainable and unsuccessful, evidenced by the fact that the problems this approach intended to solve (e.g., flood hazards, water scarcity, and channel instability) have not been solved and long‐term deterioration in river environments has reduced the capacity of rivers to continue meeting the needs of society. In response, there has been a paradigm shift in management over the past few decades, towards river restoration. But the ecological, morphological, and societal benefits of river restoration have, on the whole, been disappointing. We believe that this stems from the fact that restoration overrelies on the same physical analyses and approaches, with flowing water still regarded as the universally predominant driver of channel form and structural intervention seen as essential to influencing fluvial processes. We argue that if river restoration is to reverse long‐standing declines in river functions, it is necessary to recognize the influence of biology on river forms and processes and re‐envisage what it means to restore a river. This entails shifting the focus of river restoration from designing and constructing stable channels that mimic natural forms to reconnecting streams within balanced and healthy biomes, and so levering the power of biology to influence river processes. We define this new approach as biomic river restoration

A review of assessment methods for river hydromorphology

The work leading to this paper has received funding for the EU’s FP7 under Grant Agreement No. 282656 (REFORM

Статеві особливості метаболізму міокарда в динаміці розвитку експериментального гіпертиреозу

В экспериментах на половозрелых самцах и самках крыс исследовано активность перекисного окислення липидов, антиоксидантной защиты и энергообразования в динамике развития тироксиновой кардиомиопатии, которую моделировали введением L-тироксина (500 мг/кг, внутрижелудочно, ежедневно). В миокарде желудочков через 5, 10 и 15 дней с начала эксперимента определяли содержание диеновых и триеновых коньюгат (ДК, ТК), ТБК-активных продуктов (ТБК-АП), активность супероксиддисмутазы (СОД), каталазы, глутатионпероксидазы (ГП) и глутатионредуктазы (ГР), сукцинатдегидрогеназы (СДГ), цитохромоксидазы (ЦО). Установили, что гипертироксинемия визывала накопление в миокарде желудочков крыс ДК, ТК и ТБК-АП, что в самок было более существенным, чем у самцов, несмотря на большую активность ГП та ГР. Недостаточная протекторная эффективность ферментов системы глутатиона была результатом значительного угнетения активности СОД и каталазы, что свидетельствовало о существенном накоплении активных форм кислорода. Активность энергообразования в таких условиях уменьшалась, о чем свидетельствовало угнетение активности СДГ, которое было аналогичным в самцов и самок, и ЦО, что было более существенным в самок. Полученные результаты свидетельствуют о том, что развитие тироксиновой кардиомиопатии вызывает существенный метаболический дисбаланс в миокарде желудочков самок крыс, что разрешает ожидать болем интенсивные структурные нарушения.Lipid peroxidation, antioxidant protection and energy production were studied in adult male and female rats with thyroxin cardiomyopathy, which simulated by introduction of L-thyroxine (500 mg / kg, intraperitoneally, daily). In the myocardium of the ventricles after 5, 10 and 15 days from the start of the experiment determined the content of diene and triene conjugate (DC, TC), TBA-active metabolits (TBA-am), activity of superoxide dismutase (SOD), catalase, glutathione peroxidase (GP) and glutathione reductase (GR), succinate dehydrogenase (SDH), cytochrome oxidase (CO). Found that hyperthyroxinemia caused accumulation in myocardium of the ventricles DC, TC and TBA-am mostly in females despite the higher activity of GP and GR. Lack of protective effects of glutathione system enzymes resulted from significant inhibition of SOD and catalase, indicating a significant accumulation of reactive species of oxygen. Activity of the energy production in these conditions decreased. That was proved by the inhibition of SDH in myocardium both sex animals and CO mostly in females. We conclude that the development of thyroxin cardiomyopathy causes metabolic disbalance in myocardium of the ventricles mostly in female rats, which can results in more intense structural damage

Restoring Rivers and Floodplains for Habitat and Flood Risk Reduction: Experiences in Multi-Benefit Floodplain Management From California and Germany

Conventional flood control has emphasized structural measures such as levees, reservoirs, and engineered channels—measures that typically simplify river channels and cut them off from their floodplain, both with adverse environmental consequences. Structural measures tend to be rigid and not easily adapted to increased flooding regimes resulting from environmental change. Such actions also limit the natural hydrologic benefits of floodplains such as storing floodwaters, improving water quality, providing habitat for invertebrates and fish during periods of inundation, and supporting a multitude of cultural services. As these benefits are more widely recognized, policies are being adopted to encourage projects that reduce flood risks and restore floodplain ecosystems, while acknowledging the social-ecological context. The number of such projects, however, remains small. We assessed four multi-benefit floodplain projects (two in California, United States, and two in Germany) and characterized their drivers, history, and measures implemented. In both United States cases, the dominant driver behind the project was flood risk reduction, and ecosystem restoration followed, in one case inadvertently, in the other as a requirement to receive a subsidy for a flood risk reduction project. One German case was motivated by ecosystem restoration, but it was more widely accepted because it also offered flood management benefits. The fourth case was conceived in terms of balanced goals of flood risk reduction, ecosystem restoration, and recreation. We conclude that projects that both reduce flood risk and restore ecosystems are clearly possible and often cost-effective, and that they could be more widely implemented. The principal barriers are often institutional and regulatory, rather than technical

Prioritization of fish communities with a view to conservation and restoration on a large scale European basin, the Loire (France)

The hierarchical organization of important sites for the conservation or the restoration of fish communities is a great challenge for managers, especially because of financial or time constraints. In this perspective, we developed a methodology, which is easy to implement in different locations. Based on the fish assemblage characteristics of the Loire basin (France), we created a synthetic conservation value index including the rarity, the conservation status and the species origin. The relationship between this new synthetic index and the Fish-Based Index allowed us to establish a classification protocol of the sites along the Loire including fish assemblages to be restored or conserved. Sites presenting disturbed fish assemblages, a low rarity index, few threatened species, and a high proportion of non-native species were considered as important for the restoration of fish biodiversity. These sites were found mainly in areas where the assemblages are typical of the bream zone, e.g. with a higher number of eurytopic and limnophilic species. On the contrary, important sites for conservation were defined as having an important conservation potential (high RI, a lot of threatened species, and few nonnatives fish species) and an undisturbed fish assemblage similar to the expected community if habitats are undisturbed. Important sites for conservation were found in the Loire basin’s medium reaches which host assemblages typical for the grayling and the barbell zones, e.g. with a higher number of rheophilic species. The synthetic conservation value index could be adapted and completed with other criteria according to management priorities and capacities

Mosaic RAS/MAPK variants cause sporadic vascular malformations which respond to targeted therapy.

BACKGROUND: Sporadic vascular malformations (VMs) are complex congenital anomalies of blood vessels that lead to stroke, life-threatening bleeds, disfigurement, overgrowth, and/or pain. Therapeutic options are severely limited, and multidisciplinary management remains challenging, particularly for high-flow arteriovenous malformations (AVM). METHODS: To investigate the pathogenesis of sporadic intracranial and extracranial VMs in 160 children in which known genetic causes had been excluded, we sequenced DNA from affected tissue and optimized analysis for detection of low mutant allele frequency. RESULTS: We discovered multiple mosaic-activating variants in 4 genes of the RAS/MAPK pathway, KRAS, NRAS, BRAF, and MAP2K1, a pathway commonly activated in cancer and responsible for the germline RAS-opathies. These variants were more frequent in high-flow than low-flow VMs. In vitro characterization and 2 transgenic zebrafish AVM models that recapitulated the human phenotype validated the pathogenesis of the mutant alleles. Importantly, treatment of AVM-BRAF mutant zebrafish with the BRAF inhibitor vemurafinib restored blood flow in AVM. CONCLUSION: Our findings uncover a major cause of sporadic VMs of different clinical types and thereby offer the potential of personalized medical treatment by repurposing existing licensed cancer therapies. FUNDING: This work was funded or supported by grants from the AVM Butterfly Charity, the Wellcome Trust (UK), the Medical Research Council (UK), the UK National Institute for Health Research, the L'Oreal-Melanoma Research Alliance, the European Research Council, and the National Human Genome Research Institute (US)