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https://www.readbyqxmd.com/read/28991965/meta-analysis-of-phosphorus-loss-from-no-till-soils
#1
Stefani Daryanto, Lixin Wang, Pierre André Jacinthe
Agriculture is a significant contributor to phosphorus (P) enrichment in aquatic ecosystems. No-till (NT) farming has been proposed as an alternative approach to conventional tillage (CT) in reducing soil P export, but published data have shown contrasting impacts, likely due to the interacting effects of different physical (climate region, rainfall variability, transport pathway, slope gradient) and management variables (NT duration, crop species). We conducted a meta-analysis to understand the extent to which each of these variables controls the concentration and load of different P fractions (dissolved P, particulate P) in agricultural runoff and leaching...
September 2017: Journal of Environmental Quality
https://www.readbyqxmd.com/read/28987730/excess-lead-210-and-plutonium-239-240-two-suitable-radiogenic-soil-erosion-tracers-for-mountain-grassland-sites
#2
K Meusburger, P Porto, L Mabit, C La Spada, L Arata, C Alewell
The expected growing population and challenges associated with globalisation will increase local food and feed demands and enhance the pressure on local and regional upland soil resources. In light of these potential future developments it is necessary to define sustainable land use and tolerable soil loss rates with methods applicable and adapted to mountainous areas. Fallout-radionuclides (FRNs) are proven techniques to increase our knowledge about the status and resilience of agro-ecosystems. However, the use of the Caesium-137 ((137)Cs) method is complicated in the European Alps due to its heterogeneous input and the timing of the Chernobyl fallout, which occurred during a few single rain events on partly snow covered ground...
October 5, 2017: Environmental Research
https://www.readbyqxmd.com/read/28982080/predicting-pesticide-fate-in-small-cultivated-mountain-watersheds-using-the-dynaplus-model-toward-improved-assessment-of-peak-exposure
#3
Melissa Morselli, Chiara Maria Vitale, Alessio Ippolito, Sara Villa, Roberto Giacchini, Marco Vighi, Antonio Di Guardo
The use of plant protection products (PPPs) in agricultural areas implies potential chemical loadings to surface waters, which can pose a risk to aquatic ecosystems and human health. Due to the spatio-temporal variability of PPP applications and of the processes regulating their transport to surface waters, aquatic organisms are typically exposed to pulses of contaminants. In small mountain watersheds, where runoff fluxes are more rapid due to the steep slopes, such exposure peaks are particularly likely to occur...
October 2, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28981654/temporal-trends-in-sperm-count-a-systematic-review-and-meta-regression-analysis
#4
Hagai Levine, Niels Jørgensen, Anderson Martino-Andrade, Jaime Mendiola, Dan Weksler-Derri, Irina Mindlis, Rachel Pinotti, Shanna H Swan
BACKGROUND: Reported declines in sperm counts remain controversial today and recent trends are unknown. A definitive meta-analysis is critical given the predictive value of sperm count for fertility, morbidity and mortality. OBJECTIVE AND RATIONALE: To provide a systematic review and meta-regression analysis of recent trends in sperm counts as measured by sperm concentration (SC) and total sperm count (TSC), and their modification by fertility and geographic group...
July 25, 2017: Human Reproduction Update
https://www.readbyqxmd.com/read/28977343/trajectories-of-igf-i-predict-mortality-in-older-adults-the-cardiovascular-health-study
#5
Jason L Sanders, Wensheng Guo, Ellen S O'Meara, Robert C Kaplan, Michael N Pollak, Traci M Bartz, Anne B Newman, Linda P Fried, Anne R Cappola
Background: Disruption of insulin-like growth factor-I (IGF-I) increases health and life span in animal models, though this is unconfirmed in humans. If IGF-I stability indicates homeostasis, the absolute level of IGF-I may be less clinically relevant than maintaining an IGF-I setpoint. Methods: Participants were 945 U.S. community-dwelling individuals aged ≥65 years enrolled in the Cardiovascular Health Study with IGF-I levels at 3-6 timepoints. We examined the association of baseline IGF-I level, trajectory slope, and variability around the trajectory with mortality...
July 23, 2017: Journals of Gerontology. Series A, Biological Sciences and Medical Sciences
https://www.readbyqxmd.com/read/28976183/ion-source-with-laser-triangulation-for-ambient-mass-spectrometry-of-non-planar-samples
#6
Jan Rejsek, Vladimír Vrkoslav, Vít Pokorný, Vladimír Přibyl, Josef Cvačka
The analysis of non-planar samples in ambient mass spectrometry poses a formidable challenge. Here, an ion source equipped with laser triangulation for analyzing non-planar surfaces was constructed. It was designed as a two-position device, where the sample height was measured using laser triangulation and the target compounds were then analyzed. Thanks to a stage movable in xyz the ion source maintained an optimal vertical distance between the sample and the sampling capillary for each measured spot during the surface analysis...
October 4, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28956534/internal-current-amplification-induced-by-dielectric-hole-trapping-in-monolayer-mos-sub-2-sub-transistor
#7
Pang-Shiuan Liu, Ching-Ting Lin, Boris Hudec, Tuo-Hung Hou
Carrier transport in layered transition-metal dichalcogenides is highly sensitive to surrounding charges because of the atomically thin thickness. By exploiting this property, we report a new internal current amplification mechanism through positive feedback induced by dielectric hole trapping in a MoS<sub>2</sub> back-gate transistor on a tantalum oxide substrate. The device exhibits an extremely steep subthreshold slope of 17 mV/decade, which is strongly dependent on the substrate material and drain bias...
September 28, 2017: Nanotechnology
https://www.readbyqxmd.com/read/28883045/breath-to-breath-variability-of-exhaled-co2-as-a-marker-of-lung-dysmaturity-in-infancy
#8
Sotirios Fouzas, Ilias Theodorakopoulos, Edgar Wilfried Delgado-Eckert, Philipp Latzin, Urs Frey
The concept of diffusional screening implies that breath-to-breath variations in CO2 clearance, when related to the variability of breathing, may contain information on the quality and utilization of the available alveolar surface. We explored the validity of the above hypothesis in a cohort of young infants of comparable post-menstrual age but born at different stages of lung maturity, namely, in term-born infants (N = 128), preterm-born infants without chronic lung disease of infancy (CLDI) (N = 53) and preterm infants with moderate/severe CLDI (N = 87)...
September 7, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28877547/comparing-excitability-at-37%C3%A2-c-versus-at-20%C3%A2-c-differences-between-motor-and-sensory-axons
#9
Maria O Kovalchuk, Hessel Franssen, Leonard J Van Schelven, Boudewijn T H M Sleutjes
INTRODUCTION: In some peripheral nervous system disorders, cold induces symptoms of muscle weakness without loss of sensation. To understand this selective effect on motor function, it is first essential to delineate the effects of cooling in motor and sensory axons of healthy subjects. METHODS: In 17 healthy volunteers, we performed excitability and clinical tests of median nerve motor and sensory axons at 37°C and at 20°C. Clinical tests consisted of assessing thenar muscle strength, 2-point discrimination, and joint position sense of the third finger...
September 6, 2017: Muscle & Nerve
https://www.readbyqxmd.com/read/28860675/changes-of-forest-cover-and-disturbance-regimes-in-the-mountain-forests-of-the-alps
#10
P Bebi, R Seidl, R Motta, M Fuhr, D Firm, F Krumm, M Conedera, C Ginzler, T Wohlgemuth, D Kulakowski
Natural disturbances, such as avalanches, snow breakage, insect outbreaks, windthrow or fires shape mountain forests globally. However, in many regions over the past centuries human activities have strongly influenced forest dynamics, especially following natural disturbances, thus limiting our understanding of natural ecological processes, particularly in densely-settled regions. In this contribution we briefly review the current understanding of changes in forest cover, forest structure, and disturbance regimes in the mountain forests across the European Alps over the past millennia...
March 15, 2017: Forest Ecology and Management
https://www.readbyqxmd.com/read/28846492/planktonic-subsidies-to-surf-zone-and-intertidal-communities
#11
Steven G Morgan, Alan L Shanks, Jamie H MacMahan, Ad J H M Reniers, Falk Feddersen
Plankton are transported onshore, providing subsidies of food and new recruits to surf-zone and intertidal communities. The transport of plankton to the surf zone is influenced by wind, wave, and tidal forcing, and whether they enter the surf zone depends on alongshore variation in surf-zone hydrodynamics caused by the interaction of breaking waves with coastal morphology. Areas with gently sloping shores and wide surf zones typically have orders-of-magnitude-higher concentrations of plankton in the surf zone and dense larval settlement in intertidal communities because of the presence of bathymetric rip currents, which are absent in areas with steep shores and narrow surf zones...
August 28, 2017: Annual Review of Marine Science
https://www.readbyqxmd.com/read/28846015/evaluation-of-a-web-based-error-reporting-surveillance-system-in-a-large-iranian-hospital
#12
Mehrdad Askarian, Mahboobeh Ghoreishi, Hourvash Akbari Haghighinejad, Charles John Palenik, Maryam Ghodsi
BACKGROUND: Proper reporting of medical errors helps healthcare providers learn from adverse incidents and improve patient safety. A well-designed and functioning confidential reporting system is an essential component to this process. There are many error reporting methods; however, web-based systems are often preferred because they can provide; comprehensive and more easily analyzed information. This study addresses the use of a web-based error reporting system. METHODS: This interventional study involved the application of an in-house designed "voluntary web-based medical error reporting system...
August 2017: Archives of Iranian Medicine
https://www.readbyqxmd.com/read/28841519/reduction-of-soil-erosion-and-mercury-losses-in-agroforestry-systems-compared-to-forests-and-cultivated-fields-in-the-brazilian-amazon
#13
Annie Béliveau, Marc Lucotte, Robert Davidson, Serge Paquet, Frédéric Mertens, Carlos J Passos, Christine A Romana
In addition to causing physical degradation and nutrient depletion, erosion of cultivated soils in the Amazon affects aquatic ecosystems through the release of natural soil mercury (Hg) towards lakes and rivers. While traditional agriculture is generally cited as being among the main causes of soil erosion, agroforestry practices are increasingly appreciated for soil conservation. This study was carried out in family farms of the rural Tapajós region (Brazil) and aimed at evaluating soil erosion and associated Hg release for three land uses...
August 22, 2017: Journal of Environmental Management
https://www.readbyqxmd.com/read/28833612/a-1d-vanadium-dioxide-nanochannel-constructed-via-electric-field-induced-ion-transport-and-its-superior-metal-insulator-transition
#14
Wuhong Xue, Gang Liu, Zhicheng Zhong, Yuehua Dai, Jie Shang, Yiwei Liu, Huali Yang, Xiaohui Yi, Hongwei Tan, Liang Pan, Shuang Gao, Jun Ding, Xiao-Hong Xu, Run-Wei Li
Nanoscale manipulation of materials' physicochemical properties offers distinguished possibility to the development of novel electronic devices with ultrasmall dimension, fast operation speed, and low energy consumption characteristics. This is especially important as the present semiconductor manufacturing technique is approaching the end of miniaturization campaign in the near future. Here, a superior metal-insulator transition (MIT) of a 1D VO2 nanochannel constructed through an electric-field-induced oxygen ion migration process in V2 O5 thin film is reported for the first time...
August 21, 2017: Advanced Materials
https://www.readbyqxmd.com/read/28818453/two-locus-clines-on-the-real-line-with-a-step-environment
#15
Reinhard Bürger
The shape of allele-frequency clines maintained by migration-selection balance depends not only on the properties of migration and selection, but also on the dominance relations among alleles and on linkage to other loci under selection. We investigate a two-locus model in which two diallelic, recombining loci are subject to selection caused by an abrupt environmental change. The habitat is one-dimensional and unbounded, selection at each locus is modeled by step functions such that in one region one allele at each locus is advantageous and in the other deleterious...
October 2017: Theoretical Population Biology
https://www.readbyqxmd.com/read/28811195/epileptic-interictal-discharges-are-more-frequent-during-nrem-slow-wave-downstates
#16
Péter Przemyslaw Ujma, Péter Halász, Anna Kelemen, Dániel Fabó, Loránd Erőss
Epileptiform activity in various but not all epilepsy and recording types and cerebral areas is more frequent in NREM sleep, and especially during sleep periods with high-amplitude EEG slow waves. Slow waves synchronize high-frequency oscillations: physiological activity from the theta through the gamma band usually appears during scalp-positive upstates while epileptiform activity occurs at transitory phases and the scalp-negative downstate. It has been proposed that interictal discharges (IIDs) are facilitated by the high degree of neuronal firing synchrony during slow wave transitory and downstates...
September 29, 2017: Neuroscience Letters
https://www.readbyqxmd.com/read/28800546/mr-based-respiratory-and-cardiac-motion-correction-for-pet-imaging
#17
Thomas Küstner, Martin Schwartz, Petros Martirosian, Sergios Gatidis, Ferdinand Seith, Christopher Gilliam, Thierry Blu, Hadi Fayad, Dimitris Visvikis, F Schick, B Yang, H Schmidt, N F Schwenzer
PURPOSE: To develop a motion correction for Positron-Emission-Tomography (PET) using simultaneously acquired magnetic-resonance (MR) images within 90 s. METHODS: A 90 s MR acquisition allows the generation of a cardiac and respiratory motion model of the body trunk. Thereafter, further diagnostic MR sequences can be recorded during the PET examination without any limitation. To provide full PET scan time coverage, a sensor fusion approach maps external motion signals (respiratory belt, ECG-derived respiration signal) to a complete surrogate signal on which the retrospective data binning is performed...
August 3, 2017: Medical Image Analysis
https://www.readbyqxmd.com/read/28794520/iran-s-land-suitability-for-agriculture
#18
Mohsen B Mesgaran, Kaveh Madani, Hossein Hashemi, Pooya Azadi
Increasing population has posed insurmountable challenges to agriculture in the provision of future food security, particularly in the Middle East and North Africa (MENA) region where biophysical conditions are not well-suited for agriculture. Iran, as a major agricultural country in the MENA region, has long been in the quest for food self-sufficiency, however, the capability of its land and water resources to realize this goal is largely unknown. Using very high-resolution spatial data sets, we evaluated the capacity of Iran's land for sustainable crop production based on the soil properties, topography, and climate conditions...
August 9, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28768512/theory-of-synergistic-effects-hill-type-response-surfaces-as-null-interaction-models-for-mixtures
#19
Michael Schindler
BACKGROUND: The classification of effects caused by mixtures of agents as synergistic, antagonistic or additive depends critically on the reference model of 'null interaction'. Two main approaches are currently in use, the Additive Dose (ADM) or concentration addition (CA) and the Multiplicative Survival (MSM) or independent action (IA) models. We compare several response surface models to a newly developed Hill response surface, obtained by solving a logistic partial differential equation (PDE)...
August 2, 2017: Theoretical Biology & Medical Modelling
https://www.readbyqxmd.com/read/28768317/hue-shifts-produced-by-temporal-asymmetries-in-chromatic-signals
#20
Andrew Stockman, G Bruce Henning, Peter West, Andrew T Rider, Hannah E Smithson, Caterina Ripamonti
Observers viewed M- or L-cone-isolating stimuli and compared slowly-on and slowly-off sawtooth waveforms of the same mean chromaticity and luminance. Between 6 and 13 Hz, the mean hue of slowly-on L-cone and slowly-off M-cone sawtooth flicker appeared redder, and the mean hue of slowly-off L-cone and slowly-on M-cone sawtooth stimuli appeared greener-despite all the waveforms' having the same mean, near-yellow-appearing chromaticity. We measured the effect of the modulation depth and the slope of the sawtooth on the mean hue shifts as a function of temporal frequency...
August 1, 2017: Journal of Vision
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