Circuit development in the master clock network of mammals

Daily rhythms are generated by the circadian timekeeping system, which is orchestrated by the master circadian clock in the suprachiasmatic nucleus (SCN) of mammals. Circadian timekeeping is endogenous and does not require exposure to external cues during development. Nevertheless, the circadian system is not fully formed at birth in many mammalian species and it is important to understand how SCN development can affect the function of the circadian system in adulthood. The purpose of the current review is to discuss the ontogeny of cellular and circuit function in the SCN, with a focus on work performed in model rodent species (i.e., mouse, rat, and hamster). Particular emphasis is placed on the spatial and temporal patterns of SCN development that may contribute to the function of the master clock during adulthood. Additional work aimed at decoding the mechanisms that guide circadian development is expected to provide a solid foundation upon which to better understand the sources and factors contributing to aberrant maturation of clock function

How to quantify heavy mineral fertility from point‐counting data

Heavy minerals (HM) are widely used in provenance studies, for example, for reconstructing source areas and quantifying sediment budgets. Source rock mineral fertility influences the composition and concentration of HM in sediments. The resulting bias is of particular interest when interpreting single-grain data such as detrital age distributions. However, the quantification of fertility is complex and there are no robust data for most HM, which prevents the routine implementation of fertility in many studies. In this study, we test whether mineral fertility can be assessed by quantifying mineral concentrations in detrital samples through point counting and quantitative evaluation of minerals by scanning electron microscopy (QEMSCAN). The challenge is to transform the resulting area percentage into mass percentage, which is a prerequisite for comparing those data with grain size or geochemical data. We suggest overcoming this problem by recording grain-size and shape metrics of minerals using image analysis, and applying several transformation steps. We test our method by (a) using a series of detrital grain mixtures of known density and mass, and (b) applying it to a natural sediment from the European Alps. Our results agree with existing methods developed for apatite and zircon, that is, the quantification of fertility through geochemistry (with P2O5 and Zr concentrations as proxies for apatite and zircon) and the separation of pure apatite and zircon concentrates using additional separation steps. The advantage of our method is its applicability to all HM (not only apatite and zircon) and the redundancy of additional separation steps, which might create bias

Glacial catchment erosion from detrital zircon (U‐Th)/he thermochronology: Patagonian Andes

Alpine glacial erosion exerts a first-order control on mountain topography and sediment production, but its mechanisms are poorly understood. Observational data capable of testing glacial erosion and transport laws in glacial models are mostly lacking. New insights, however, can be gained from detrital tracer thermochronology. Detrital tracer thermochronology works on the premise that thermochronometer bedrock ages vary systematically with elevation, and that detrital downstream samples can be used to infer the source elevation sectors of sediments. We analyze six new detrital samples of different grain sizes (sand and pebbles) from glacial deposits and the modern river channel integrated with data from 18 previously analyzed bedrock samples from an elevation transect in the Leones Valley, Northern Patagonian Icefield, Chile (46.7°S). We present 622 new detrital zircon (U-Th)/He (ZHe) single-grain analyses and 22 new bedrock ZHe analyses for two of the bedrock samples to determine age reproducibility. Results suggest that glacial erosion was focused at and below the Last Glacial Maximum and neoglacial equilibrium line altitudes, supporting previous modeling studies. Furthermore, grain age distributions from different grain sizes (sand, pebbles) might indicate differences in erosion mechanisms, including mass movements at steep glacial valley walls. Finally, our results highlight complications and opportunities in assessing glacigenic environments, such as dynamics of sediment production, transport, transient storage, and final deposition, that arise from settings with large glacio-fluvial catchments

How steady are steady-state mountain belts? A reexamination of the Olympic Mountains (Washington state, USA)

The Olympic Mountains of Washington state (USA) represent the aerially exposed accretionary wedge of the Cascadia Subduction Zone and are thought to be in flux steady state, whereby the mass outflux (denudation) and influx (tectonic accretion) into the mountain range are balanced. We use a multi-method approach to investigate how temporal variations in the influx and outflux could affect previous interpretations of flux steady state. This includes the analysis of published and new thermochronometric ages for (U–Th)&thinsp;∕&thinsp;He dating of apatite and zircon (AHe and ZHe, respectively), fission-track dating of apatite and zircon (AFT and ZFT, respectively), 1-D thermo-kinematic modeling of thermochronometric data, and independent estimates of outflux and influx. In total, we present 61 new AHe, ZHe, AFT, and ZFT thermochronometric ages from 21 new samples. AHe ages are generally young (&lt;&thinsp;4&thinsp;Ma), and, in some samples, AFT ages (5–8&thinsp;Ma) overlap ZHe ages (7–9&thinsp;Ma) within uncertainties. Thermo-kinematic modeling shows that exhumation rates are temporally variable, with rates decreasing from &gt;&thinsp;2 to &lt;&thinsp;0.3&thinsp;km&thinsp;Myr−1 around 5–7&thinsp;Ma. With the onset of Plio–Pleistocene glaciation, exhumation rates increased to values &gt;&thinsp;1&thinsp;km&thinsp;Myr−1. This demonstrates that the material outflux varies through time, requiring a commensurate variation in influx to maintain flux steady state. Evaluation of the offshore and onshore sediment record shows that the material influx is also variable through time and that the amount of accreted sediment in the wedge is spatially variable. This qualitatively suggests that significant perturbations of steady state occur on shorter timescales (105–106 years), like those created by Plio–Pleistocene glaciation. Our quantitative assessment of influx and outflux indicates that the Olympic Mountains could be in flux steady state on long timescales (107 years).</p

Indicators for relational values of nature’s contributions to good quality of life:The IPBES approach for Europe and Central Asia

Relational values are values of desirable relationships between people and nature and among people (through nature). We report on the approach to capture relational values of nature s contributions to people in the regional assessment for Europe and Central Asia of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES). We present a framework considering indicators along four relational value dimensions about people s relationships with nature: security and sovereignty; health; equity and justice; and heritage, social identity and stewardship. The framework has been operationalized for three nature s contributions to people (NCP): regulation of freshwater quality and quantity, food and feed, and physical and psychological experiences derived from nature. We identify ways to empirically assess relational values of nature s contributions to people at regional and continental scales with social-ecological indicators and proxies, ranging from biophysical indicators to indicators that intersect socio-economic with biophysical data. We conclude that many of the identified indicators can be considered as useful proxies of relational values in a quantitative way. The analysis shows that relational values are essential to consider at the science-policy interface as they are an important set of values that people hold about nature and that go beyond instrumental relations. © 2020, © 2020 The Author(s). Published by Informa UK Limited, trading as Taylor and Francis Group

Home parenteral nutrition with an omega-3-fatty-acid-enriched MCT/LCT lipid emulsion in patients with chronic intestinal failure (the HOME study):study protocol for a randomized, controlled, multicenter, international clinical trial

BACKGROUND: Home parenteral nutrition (HPN) is a life-preserving therapy for patients with chronic intestinal failure (CIF) indicated for patients who cannot achieve their nutritional requirements by enteral intake. Intravenously administered lipid emulsions (ILEs) are an essential component of HPN, providing energy and essential fatty acids, but can become a risk factor for intestinal-failure-associated liver disease (IFALD). In HPN patients, major effort is taken in the prevention of IFALD. Novel ILEs containing a proportion of omega-3 polyunsaturated fatty acids (n-3 PUFA) could be of benefit, but the data on the use of n-3 PUFA in HPN patients are still limited. METHODS/DESIGN: The HOME study is a prospective, randomized, controlled, double-blind, multicenter, international clinical trial conducted in European hospitals that treat HPN patients. A total of 160 patients (80 per group) will be randomly assigned to receive the n-3 PUFA-enriched medium/long-chain triglyceride (MCT/LCT) ILE (Lipidem/Lipoplus® 200 mg/ml, B. Braun Melsungen AG) or the MCT/LCT ILE (Lipofundin® MCT/LCT/Medialipide® 20%, B. Braun Melsungen AG) for a projected period of 8 weeks. The primary endpoint is the combined change of liver function parameters (total bilirubin, aspartate transaminase and alanine transaminase) from baseline to final visit. Secondary objectives are the further evaluation of the safety and tolerability as well as the efficacy of the ILEs. DISCUSSION: Currently, there are only very few randomized controlled trials (RCTs) investigating the use of ILEs in HPN, and there are very few data at all on the use of n-3 PUFAs. The working hypothesis is that n-3 PUFA-enriched ILE is safe and well-tolerated especially with regard to liver function in patients requiring HPN. The expected outcome is to provide reliable data to support this thesis thanks to a considerable number of CIF patients, consequently to broaden the present evidence on the use of ILEs in HPN. TRIAL REGISTRATION: ClinicalTrials.gov, ID: NCT03282955. Registered on 14 September 2017

Integrating Spatial Educational Experiences (Isee) – Mapping a New Approach to Teaching and Learning Soil Science

The purpose of the Integrating Spatial Educational Experiences project is to develop the ability of our students to use digital maps: (1) to learn how and why soils and landscapes vary spatially at scales ranging from fields, to counties, states, and globally and (2) to learn how the spatial distribution of soils and landscapes impacts the distributions of land use, and environmental and ecosystem services across various scales. Our immediate audience is undergraduate students in soil, crop, natural resource, and environmental science curricula in colleges and universities, but the products created by this project will have broader uses for outreach to other clientele. Products to support teaching and learning include: (1) a revised and expanded Integrating Spatial Educational Experiences (Isee) web site, (2) maps of soil properties for Indiana, West Virginia, Ohio, Kentucky, Illinois, Wisconsin, and Texas, (3) a community of practice dedicated to Integrating Spatial Educational Experiences in soil science education on STEMEdhub.org, and (4) lessons, worksheets, exercises, and experiences shared with the Isee community of practice

Was sind negative Emissionen, und warum brauchen wir sie? Akademienprojekt ‘Energiesysteme der Zukunft’ (ESYS)

Selbst mit ambitionierteren Maßnahmen zur Vermeidung von Emissionen lässt sich Klimaneutralität und damit die Stabilisierung der Temperatur nicht mehr erreichen. Darauf weist der Weltklimarat in seinem sechsten Sachstandsbericht hin. Zusätzlich zu einer schnelleren Reduktion der Emissionen muss CO2 der Atmosphäre entzogen und anschließend eingelagert werden, um nicht vermeidbare Restemissionen auszugleichen, etwa aus der Landwirtschaft. Sogenannte „negative Emissionen“ können zum Beispiel durch Aufforstung erzeugt werden. Es gibt aber eine Reihe weiterer natürlicher und technischer Verfahren, den entnommenen Kohlenstoff dauerhaft einzulagern und aus der Atmosphäre fernzuhalten. In diesem „Kurz erklärt“ skizzieren Fachleute des Akademienprojekts ESYS den aktuellen Forschungsstand, erläutern Verfahren zur CO2-Entnahme und benennen deren jeweiligen Vor- und Nachteile