393 research outputs found

    PECCI Code (Python Estimation for Carbon Concentration and Isotopes) for Calculating the Concentration and Stable Carbon Isotopic Composition of Dissolved Inorganic Carbon (DIC) in Precipitation for northwestern Arkansas

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    In karst settings, hydrograph separations using isotopic tracers are commonly and effectively used to quantify the proportions of rain rapidly delivered to springs along fractures and conduits during storm events. Dissolved inorganic carbon (DIC) is an effective, non‐conservative tracer for use in hydrograph separations of karst waters because of the ubiquitous nature of carbon in the sources of waters to caves and springs and unique concentrations and isotopic compositions of carbon inputs. DIC concentration and isotopic composition (ÎŽÂčÂłC‐DIC) in rain are typically calculated based on atmospheric carbon dioxide (CO₂) using equilibrium carbonate reactions and stable carbon isotope fractionation values. As atmospheric CO₂ changes, traditional assumptions applied in attaining calculated values can result in error, and better estimates of rain DIC are needed. The concentration and isotopic composition of rain DIC in the karst of northwestern Arkansas was calculated using Pythonℱ programming language based on local atmospheric CO₂ and rain pH data from 2011 to 2013. Pythonℱ provides an open‐source code and rapid means to complete iterative calculations, and the PECCI code (Pythonℱ Estimation for Carbon Concentration and Isotopes) can be used for rain DIC calculations in other areas. Measured northwestern Arkansas atmospheric CO₂ had a median concentration of 397.7 ± 4.3 ppm and increased slightly over three years and median ÎŽÂčÂłC‐CO₂ was ‐8.5 ±0.4 ‰. Rain samples exhibited a median pH of 5.6 ±0.4. Calculated rain DIC ranged from 0.17 to 0.34 mg/L and ÎŽ13C‐DIC ranged from ‐8.5‰ to ‐8.2‰ between 5 and 30 °C. At an average annual temperature of 14.6 °C, rain DIC was calculated to be 0.25 mg/L and ÎŽÂčÂłC‐DIC was ‐8.34 ‰. Although the variations in DIC are small, the concentration and isotopic composition of end‐member sources in hydrograph separations controls the final hydrologic budget calculations. The PECCI code can be modified to calculate rain DIC for otherstudy sites or time periods

    Sensory Feedback, Error Correction, and Remapping in a Multiple Oscillator Model of Place-Cell Activity

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    Mammals navigate by integrating self-motion signals (“path integration”) and occasionally fixing on familiar environmental landmarks. The rat hippocampus is a model system of spatial representation in which place cells are thought to integrate both sensory and spatial information from entorhinal cortex. The localized firing fields of hippocampal place cells and entorhinal grid-cells demonstrate a phase relationship with the local theta (6–10 Hz) rhythm that may be a temporal signature of path integration. However, encoding self-motion in the phase of theta oscillations requires high temporal precision and is susceptible to idiothetic noise, neuronal variability, and a changing environment. We present a model based on oscillatory interference theory, previously studied in the context of grid cells, in which transient temporal synchronization among a pool of path-integrating theta oscillators produces hippocampal-like place fields. We hypothesize that a spatiotemporally extended sensory interaction with external cues modulates feedback to the theta oscillators. We implement a form of this cue-driven feedback and show that it can retrieve fixed points in the phase code of position. A single cue can smoothly reset oscillator phases to correct for both systematic errors and continuous noise in path integration. Further, simulations in which local and global cues are rotated against each other reveal a phase-code mechanism in which conflicting cue arrangements can reproduce experimentally observed distributions of “partial remapping” responses. This abstract model demonstrates that phase-code feedback can provide stability to the temporal coding of position during navigation and may contribute to the context-dependence of hippocampal spatial representations. While the anatomical substrates of these processes have not been fully characterized, our findings suggest several signatures that can be evaluated in future experiments

    Einsatz von gekeimtem Getreide in der GeflĂŒgelfĂŒtterung

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    Ab August 2005 muss die Bio-GeflĂŒgelfĂŒtterung laut EU-Bio-Verordnung (1804/1999/EG) zu 100 % mit ökologisch erzeugten Komponenten erfolgen. FĂŒr die Rationsgestaltung fallen hochwertige, konventionell erzeugte EiweißtrĂ€ger weg. Es wurde geprĂŒft, inwieweit gekeimter Weizen in 100 % Bio-Rationen zur Proteinversorgung von KĂŒken, Jung- und Legehennen beitragen kann und ob diese Rationen bedarfsgerecht sind. In zehn Bodenhaltungs-Stallabteilen ohne Außenauslauf wurden jeweils 19 Hennen und ein Hahn zweier HerkĂŒnfte (Lohmann Tradition –LT-, ISA Brown) vom Schlupf bis zur 40. Lebenswoche (LW) bei einer Besatzdichte von 5 Tieren/qm (ab der 5. LW) gehalten. Acht Versuchsgruppen wurden kombiniert mit 100 % Bio-ErgĂ€nzer und Weizenkeimen (4 Gruppen) oder -körnern (4 Gruppen) gefĂŒttert, zwei Kontrollgruppen mit Alleinfutter mit bis zu 15 % konventionellen Komponenten. Die 48-stĂŒndige Keimung des Weizens fĂŒhrte zu keinen Änderungen in den Gehalten der RohnĂ€hrstoffe, außer StĂ€rke und Zucker, und damit auch zu keiner Verbesserung der Proteinversorgung der Tiere. Einige Vitamingehalte (B1, B2, K, C) und der Gehalt der essentiellen LinolensĂ€ure stiegen an. Es gab keine signifikanten Unterschiede zwischen den Futtergruppen (Keim-, Körner und AlleinfĂŒtterung) und HerkĂŒnften in der Legeleistung, verschiedenen EiqualitĂ€tsparametern und im Gefiederzustand, außer einer Tendenz zu höheren Eigewichten in der KeimfĂŒtterungsgruppe und höheren Lebendgewichten der LT-Hennen in der 14. und 21. LW. Unter den gegebenen Bedingungen gewĂ€hrleistete die 100 % Bio-FĂŒtterung einen sehr guten Gesundheits- und Gefiederzustand der Tiere bei zufrieden stellenden Leistungen. Biophotonenmessungen ergaben signifikant höhere Dotter-Lumineszenz-Werte als bei zugekauften Eiern aus konventioneller Boden- und KĂ€fighaltung. Lediglich die nochmals höheren Werte bei den Eiern der Kontrollgruppe deuteten möglicherweise darauf hin, dass die 100 % Bio-FĂŒtterung weniger bedarfsgerecht war als die FĂŒtterung mit Alleinfutter. Zudem bestanden beim 100 % Bio-ErgĂ€nzer ein hoher Futterverbrauch und eine höhere Futtervergeudung. Weitere Untersuchung zur Bestimmung des NĂ€hrstoffbedarfs von Jung- und Legehennen unter ökologischen Haltungsbedingungen sowie zur Entwicklung bedarfsgerechter ökologischer Futterrationen sind notwendig

    Backward Shift of Head Direction Tuning Curves of the Anterior Thalamus: Comparison with CA1 Place Fields

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    SummaryThe head direction cell system is composed of multiple regions associated with the hippocampal formation. The dynamics of head direction tuning curves (HDTCs) were compared with those of hippocampal place fields. In both familiar and cue-altered environments, as a rat ran an increasing number of laps on a track, the center of mass (COM) of the HDTC tended to shift backward, similar to shifting observed in place cells. However, important differences existed between these cells in terms of the shift patterns relative to the cue-altered conditions, the proportion of backward versus forward shifts, and the time course of shift resetting. The demonstration of backward COM shifts in head direction cells and place cells suggests that similar plasticity mechanisms (such as temporally asymmetric LTP induction or spike timing-dependent plasticity) may be at work in both brain systems, and these processes may reflect a general mechanism for storing learned sequences of neural activity patterns

    Using isotopes of dissolved inorganic carbon species and water to separate sources of recharge in a cave spring, northwestern Arkansas, USA Blowing Spring Cave

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    Blowing Spring Cave in northwestern Arkansas is representative of cave systems in the karst of the Ozark Plateaus, and stable isotopes of water (ή18O and ή2H) and inorganic carbon (ή13C) were used to quantify soil-water, bedrock-matrix water, and precipitation contributions to cave-spring flow during storm events to understand controls on cave water quality. Water samples from recharge-zone soils and the cave were collected from March to May 2012 to implement a multicomponent hydrograph separation approach using ή18O and ή2H of water and dissolved inorganic carbon (ή13C–DIC). During baseflow, median ή2H and ή18O compositions were –41.6‰ and –6.2‰ for soil water and were –37.2‰ and –5.9‰ for cave water, respectively. Median DIC concentrations for soil and cave waters were 1.8 mg/L and 25.0 mg/L, respectively, and median ή13C–DIC compositions were –19.9‰ and –14.3‰, respectively. During a March storm event, 12.2 cm of precipitation fell over 82 h and discharge increased from 0.01 to 0.59 m3/s. The isotopic composition of precipitation varied throughout the storm event because of rainout, a change of 50‰ and 10‰ for ή2H and ή18O was observed, respectively. Although, at the spring, ή2H and ή18O only changed by approximately 3‰ and 1‰, respectively. The isotopic compositions of precipitation and pre-event (i.e., soil and bedrock matrix) water were isotopically similar and the two-component hydrograph separation was inaccurate, either overestimating (>100%) or underestimating (<0%) the precipitation contribution to the spring. During the storm event, spring DIC and ή13C–DIC decreased to a minimum of 8.6 mg/L and –16.2‰, respectively. If the contribution from precipitation was assumed to be zero, soil water was found to contribute between 23 to 72% of the total volume of discharge. Although the assumption of negligible contributions from precipitation is unrealistic, especially in karst systems where rapid flow through conduits occurs, the hydrograph separation using inorganic carbon highlights the importance of considering vadose-zone soil water when analyzing storm chemohydrographs.Keywords: carbon, stable isotopes, cave, hydrograph, Arkansas.DOI: 10.3986/ac.v42i2-3.66

    LBT/LUCIFER Observations of the z~2 Lensed Galaxy J0900+2234

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    We present rest-frame optical images and spectra of the gravitationally lensed, star-forming galaxy J0900+2234 (z=2.03). The observations were performed with the newly commissioned LUCIFER1 near-infrared instrument mounted on the Large Binocular Telescope (LBT). We fit lens models to the rest-frame optical images and find the galaxy has an intrinsic effective radius of 7.4 kpc with a lens magnification factor of about 5 for the A and B components. We also discovered a new arc belonging to another lensed high-z source galaxy, which makes this lens system a potential double Einstein ring system. Using the high S/N rest-frame optical spectra covering H+K band, we detected Hbeta, OIII, Halpha, NII and SII emission lines. Detailed physical properties of this high-z galaxy were derived. The extinction towards the ionized HII regions (E_g(B-V)) is computed from the flux ratio of Halpha and Hbeta and appears to be much higher than that towards stellar continuum (E_s(B-V)), derived from the optical and NIR broad band photometry fitting. The metallicity was estimated using N2 and O3N2 indices. It is in the range of 1/5-1/3 solar abundance, which is much lower than the typical z~2 star-forming galaxies. From the flux ratio of SII 6717 and 6732, we found that the electron number density of the HII regions in the high-z galaxy were >1000 cm^-3, consistent with other z~2 galaxies but much higher than that in local HII regions. The star-formation rate was estimated via the Halpha luminosity, after correction for the lens magnification, to be about 365\pm69 Msun/yr. Combining the FWHM of Halpha emission lines and the half-light radius, we found the dynamical mass of the lensed galaxy is 5.8\pm0.9x10^10 Msun. The gas mass is 5.1\pm1.1x10^10~Msun from the H\alpha flux surface density by using global Kennicutt-Schmidt Law, indicating a very high gas fraction of 0.79\pm0.19 in J0900+2234.Comment: 11 pages, 6 figures accepted by ApJ, revised based on referee repor

    Novel bi-allelic variants expand the SPTBN4-related genetic and phenotypic spectrum

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    Neurodevelopmental disorder with hypotonia, neuropathy, and deafness (NEDHND, OMIM #617519) is an autosomal recessive disease caused by homozygous or compound heterozygous variants in SPTBN4 coding for type 4 beta IV-spectrin, a non-erythrocytic member of the beta-spectrin family. Variants in SPTBN4 disrupt the cytoskeletal machinery that controls proper localization of ion channels and the function of axonal domains, thereby generating severe neurological dysfunction. We set out to analyze the genetic causes and describe the clinical spectrum of suspected cases of NEDHND. Variant screening was done by whole exome sequencing; clinical phenotypes were described according to the human phenotype ontology, and histochemical analysis was performed with disease-specific antibodies. We report four families with five patients harboring novel homozygous and compound heterozygous SPTBN4 variants, amongst them a multi-exon deletion of SPTBN4. All patients presented with the key features of NEDHND; severe muscular hypotonia, dysphagia, absent speech, gross motor, and mental retardation. Additional symptoms comprised horizontal nystagmus, epileptiform discharges in EEG without manifest seizures, and choreoathetosis. Muscle histology revealed both characteristics of myopathy and of neuropathy. This report expands the SPTBN4 variant spectrum, highlights the spectrum of morphological phenotypes of NEDHND-patients, and reveals clinical similarities between the NEDHND, non-5q SMA, and congenital myopathies

    Agricultural land use changes – a scenario-based sustainability impact assessment for Brandenburg, Germany

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    AbstractDecisions for agricultural management are taken at farm scale. However, such decisions may well impact upon regional sustainability. Two of the likely agricultural management responses to future challenges are extended use of irrigation and increased production of energy crops. The drivers for these are high commodity prices and subsidy policies for renewable energy. However, the impacts of these responses upon regional sustainability are unknown. Thus, we conducted integrated impact assessments for agricultural intensification scenarios in the federal state of Brandenburg, Germany, for 2025. One Irrigation scenario and one Energy scenario were contrasted with the Business As Usual (BAU) scenario. We applied nine indicators to analyze the economic, social and environmental effects at the regional, in this case district scale, which is the smallest administrative unit in Brandenburg. Assessment results were discussed in a stakeholder workshop involving 16 experts from the state government.The simulated area shares of silage maize for fodder and energy were 29%, 37% and 49% for the BAU, Irrigation, and Energy scenarios, respectively. The Energy scenario increased bio-electricity production to 41% of the demand of Brandenburg, and it resulted in CO2 savings of up to 3.5milliontons. However, it resulted in loss of biodiversity, loss of landscape scenery, increased soil erosion risk, and increased area demand for water protection requirements. The Irrigation scenario led to yield increases of 7% (rapeseed), 18% (wheat, sugar beet), and 40% (maize) compared to the BAU scenario. It also reduced the year-to-year yield variability. Water demand for irrigation was found to be in conflict with other water uses for two of the 14 districts. Spatial differentiation of scenario impacts showed that districts with medium to low yield potentials were more affected by negative impacts than districts with high yield potentials.In this first comprehensive sustainability impact assessment of agricultural intensification scenarios at regional level, we showed that a considerable potential for agricultural intensification exists. The intensification is accompanied by adverse environmental and socio-economic impacts. The novelty lies in the multiscale integration of comprehensive, agricultural management simulations with regional level impact assessment, which was achieved with the adequate use of indicators. It provided relevant evidence for policy decision making. Stakeholders appreciated the integrative approach of the assessment, which substantiated ongoing discussions among the government bodies. The assessment approach and the Brandenburg case study may stay exemplary for other regions in the world where similar economic and policy driving forces are likely to lead to agricultural intensification

    Nematology in the North Central Region, 1956-1966

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    There have been many accomplishments in nematology in the North Central Region during the past decade. As a result of the organization of a regional nematology committee, research and teaching in the area have been greatly expanded. New problems of major agricultural significance have been discovered, and some of suspected significance have been revealed. An awareness has developed of a large and important group of animals, many of them plant parasites. Because of sheer numbers alone, nematodes deserve more attention by biologists in all aspects.https://lib.dr.iastate.edu/specialreports/1055/thumbnail.jp

    Functional Differences in the Backward Shifts of CA1 and CA3 Place Fields in Novel and Familiar Environments

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    Insight into the processing dynamics and other neurophysiological properties of different hippocampal subfields is critically important for understanding hippocampal function. In this study, we compared shifts in the center of mass (COM) of CA3 and CA1 place fields in a familiar and completely novel environment. Place fields in CA1 and CA3 were simultaneously recorded as rats ran along a closed loop track in a familiar room followed by a session in a completely novel room. This process was repeated each day over a 4-day period. CA3 place fields shifted backward (opposite to the direction of motion of the rat) only in novel environments. This backward shift gradually diminished across days, as the novel environment became more familiar with repeated exposures. Conversely, CA1 place fields shifted backward across all days in both familiar and novel environments. Prior studies demonstrated that CA1 place fields on average do not exhibit a backward shift during the first exposure to an environment in which the familiar cues are rearranged into a novel configuration, although CA3 place fields showed a strong backward shift. Under the completely novel conditions of the present study, no dissociation was observed between CA3 and CA1 during the first novel session (although a strong dissociation was observed in the familiar sessions and the later novel sessions). In summary, this is the first study to use simultaneous recordings in CA1 and CA3 to compare place field COM shift and other associated properties in truly novel and familiar environments. This study further demonstrates functional differentiation between CA1 and CA3 as the plasticity of CA1 place fields is affected differently by exposure to a completely novel environment in comparison to an altered, familiar environment, whereas the plasticity of CA3 place fields is affected similarly during both types of environmental novelty
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