35 research outputs found
Bofedal wetland and glacial melt contributions to dry season streamflow in a highâAndean headwater watershed
In the context of expected future melt reductions in the high-Andes, the buffering capacity of non-glacial stores, and especially of high-altitude bofedal wetlands, is of increasing importance. Isotope signatures potentially indicative of water undergoing evaporation on transit through bofedales have been found in the tropics, but end-member uncertainty has so far prevented streamflow separation using this signal. We undertook a stable isotope sampling campaign over the 2022 wet-dry season transition in a 53.6âkm2, 16% glacierized catchment in southern Peru with a bofedal coverage of 11%. Diurnal proglacial hydrographs and remote sensing were used to interpret seasonal snowmelt dynamics and identify the dry periods when glacial melt and bofedal contributions are assessed to be the two principal components of streamflow. Following the final wet season precipitation event, a rapid ~3âweek transition occurs in the main river from a stable isotope signature consistent with dynamic rainfall/snowmelt contributions to one of ice-melt. In both wet and dry seasons, the main river and tributary streams show evaporative enrichment suggesting ongoing supply from water transiting bofedales. A two-component mixing model using lc-excess during the dry season shows the bofedal source contribution varies from 9% to 20% [±9â10%], indicating that streamflow is greatly augmented by the presence of glaciers at these headwater scales. However, applying these proportions to river discharge shows a sustained bofedal contribution of around 0.09âm3/s during the dry season study window whereas the flux of glacial water halves from 0.73 to 0.36âm3/s over this timeframe. The results highlight the important role of bofedales and the connected groundwater system in buffering seasonal declines in streamflow months into the dry season, and suggests the hydrological functioning of bofedales as part of this wider system should be considered when exploring the effectiveness of potential options to sustain baseflows in a post-glacial future
Twenty-three unsolved problems in hydrology (UPH) â a community perspective
This paper is the outcome of a community initiative to identify major unsolved scientific problems in hydrology motivated by a need for stronger harmonisation of research efforts. The procedure involved a public consultation through on-line media, followed by two workshops through which a large number of potential science questions were collated, prioritised, and synthesised. In spite of the diversity of the participants (230 scientists in total), the process revealed much about community priorities and the state of our science: a preference for continuity in research questions rather than radical departures or redirections from past and current work. Questions remain focussed on process-based understanding of hydrological variability and causality at all space and time scales.
Increased attention to environmental change drives a new emphasis on understanding how change propagates across interfaces within the hydrological system and across disciplinary boundaries. In particular, the expansion of the human footprint raises a new set of questions related to human interactions with nature and water cycle feedbacks in the context of complex water management problems. We hope that this reflection and synthesis of the 23 unsolved problems in hydrology will help guide research efforts for some years to come
Molecular mechanisms of cell death: recommendations of the Nomenclature Committee on Cell Death 2018.
Over the past decade, the Nomenclature Committee on Cell Death (NCCD) has formulated guidelines for the definition and interpretation of cell death from morphological, biochemical, and functional perspectives. Since the field continues to expand and novel mechanisms that orchestrate multiple cell death pathways are unveiled, we propose an updated classification of cell death subroutines focusing on mechanistic and essential (as opposed to correlative and dispensable) aspects of the process. As we provide molecularly oriented definitions of terms including intrinsic apoptosis, extrinsic apoptosis, mitochondrial permeability transition (MPT)-driven necrosis, necroptosis, ferroptosis, pyroptosis, parthanatos, entotic cell death, NETotic cell death, lysosome-dependent cell death, autophagy-dependent cell death, immunogenic cell death, cellular senescence, and mitotic catastrophe, we discuss the utility of neologisms that refer to highly specialized instances of these processes. The mission of the NCCD is to provide a widely accepted nomenclature on cell death in support of the continued development of the field
A study of CP violation in B-+/- -> DK +/- and B-+/- -> D pi(+/-) decays with D -> (KSK +/-)-K-0 pi(-/+) final states
A first study of CP violation in the decay modes and , where labels a or meson and labels a or meson, is performed. The analysis uses the LHCb data set collected in collisions, corresponding to an integrated luminosity of 3 fb. The analysis is sensitive to the CP-violating CKM phase through seven observables: one charge asymmetry in each of the four modes and three ratios of the charge-integrated yields. The results are consistent with measurements of using other decay modes
Measurement of Upsilon production in collisions at root s=2.76 TeV
The production of , and mesons decaying into the dimuon final state is studied with the LHCb detector using a data sample corresponding to an integrated luminosity of 3.3 collected in proton-proton collisions at a centre-of-mass energy of TeV. The differential production cross-sections times dimuon branching fractions are measured as functions of the transverse momentum and rapidity, over the ranges $p_{\rm T} Upsilon(1S) X) x B(Upsilon(1S) -> mu+mu-) = 1.111 +/- 0.043 +/- 0.044 nb, sigma(pp -> Upsilon(2S) X) x B(Upsilon(2S) -> mu+mu-) = 0.264 +/- 0.023 +/- 0.011 nb, sigma(pp -> Upsilon(3S) X) x B(Upsilon(3S) -> mu+mu-) = 0.159 +/- 0.020 +/- 0.007 nb, where the first uncertainty is statistical and the second systematic
Study of forward Z + jet production in pp collisions at âs=7 TeV
A measurement of the +jet production cross-section in collisions at a centre-of-mass energy TeV is presented. The analysis is based on an integrated luminosity of recorded by the LHCb experiment. Results are shown with two jet transverse momentum thresholds, 10 and 20 GeV, for both the overall cross-section within the fiducial volume, and for six differential cross-section measurements. The fiducial volume requires that both the jet and the muons from the Z boson decay are produced in the forward direction (). The results show good agreement with theoretical predictions at the second-order expansion in the coupling of the strong interaction.A measurement of the +jet production cross-section in collisions at a centre-of-mass energy TeV is presented. The analysis is based on an integrated luminosity of recorded by the LHCb experiment. Results are shown with two jet transverse momentum thresholds, 10 and 20 GeV, for both the overall cross-section within the fiducial volume, and for six differential cross-section measurements. The fiducial volume requires that both the jet and the muons from the Z boson decay are produced in the forward direction (). The results show good agreement with theoretical predictions at the second-order expansion in the coupling of the strong interaction
ArrĂȘt "Servizio Elettrico Nazionale" : abus de position dominante dĂ©coulant de pratiques dâĂ©viction dans le contexte de la libĂ©ralisation du marchĂ© Ă©lectrique
Dans son arrĂȘt Servizio Elettrico Nazionale [2], la Cour de justice confirme - et Ă©tend - sa jurisprudence Post Danmark et Intel en soulignant l'importance de l'analyse in concreto des effets anticoncurrentiels (potentiels) des pratiques de l'entreprise dominante sur le marchĂ© concernĂ©, ce comportement devant ĂȘtre Ă©valuĂ© au regard de l'ensemble des circonstances juridiques, Ă©conomiques et factuelles pertinentes. L'arrĂȘt commentĂ© clarifie le test applicable en vue d'Ă©valuer si les pratiques concernĂ©es s'Ă©cartent de la concurrence dite « normale » ou « par les mĂ©rites », en consacrant un critĂšre gĂ©nĂ©ral de rĂ©plicabilitĂ© par un hypothĂ©tique concurrent aussi efficace. Les enseignements de cet arrĂȘt doivent nĂ©anmoins ĂȘtre lus Ă la lumiĂšre du contexte spĂ©cifique de cette affaire, qui concerne l'adoption par l'ancien titulaire d'un monopole lĂ©gal d'une stratĂ©gie claire d'Ă©viction de la concurrence au travers de l'utilisation des avantages tirĂ©s de cette ancienne situation de monopole, Ă savoir des bases de donnĂ©es relatives aux clients
Cloning and Characterization of <i>Drosophila melanogaster</i> Juvenile Hormone Epoxide Hydrolases (JHEH) and Their Promoters
Juvenile hormone epoxide hydrolase (JHEH) plays an important role in the metabolism of JH III in insects. To study the control of JHEH in female Drosophila melanogaster, JHEH 1, 2 and 3 cDNAs were cloned and sequenced. Northern blot analyses showed that the three transcripts are expressed in the head thorax, the gut, the ovaries and the fat body of females. Molecular modeling shows that the enzyme is a homodimer that binds juvenile hormone III acid (JH IIIA) at the catalytic groove better than JH III. Analyses of the three JHEH promoters and expressing short promoter sequences behind a reporter gene (lacZ) in D. melanogaster cell culture identified a JHEH 3 promoter sequence (626 bp) that is 10- and 25-fold more active than the most active promoter sequences of JHEH 2 and JHEH 1, respectively. A transcription factor (TF) Sp1 that is involved in the activation of JHEH 3 promoter sequence was identified. Knocking down Sp1 using dsRNA inhibited the transcriptional activity of this promoter in transfected D. melanogaster cells and JH III and 20HE downregulated the JHEH 3 promoter. On the other hand, JH IIIA and farnesoic acid did not affect the promoter, indicating that JH IIIA is JHEHâs preferred substrate. A transgenic D. melanogaster expressing a highly activated JHEH 3 promoter behind a lacZ reporter gene showed promoter transcriptional activity in many D. melanogaster tissues