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The sensitivity of snowpack sublimation estimates to instrument and measurement uncertainty perturbed in a Monte Carlo framework

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Frontiers of Earth Science 2018年第4期12卷 728-738页

作者： d.M.HULTSTRANd S.R.FASSNACHT EASC-Watershed Science Colorado State UniversityFort CollinsCO 80523-1482USA ESS-Watershed Science Colorado State UniversityFort CollinsCO 80523-1476USA Cooperative Institute for Research in the Atmosphere Fort CollinsCO 80523-1375USA Geographisches Institut Abt.KartographieGIS &FemerkundungGeorg-August-Universitat Gottingen37077GottingenGermany Natural Resources Ecology Laboratory Fort CollinsCO 80523-1499USA

The bulk aerodynamic flux equation is often used to estimate snowpack sublimation since it requires meteorological measurements at only one height above the snow surface. However, to date the uncertainty of these estimates and the individual input variables and input parameters uncertainty have not been quantified. We modeled sublimation for three (average snowpack in 2005, deep snowpack in 2011, and shallow snowpack in 2012) different water years (October 1 to September 30) at West Glacier Lake watershed within the Glacier Lakes Ecosystem Experiments Site in *** performed a Monte Carlo analysis to evaluate the sensitivity of modeled sublimation to uncertainties of the input variables and parameters from the bulk aerodynamic flux equation. Input variable time series were uniformly adjusted by a normally distributed random variable with a standard deviation given as follows: 1) the manufacturer’s stated instrument accuracy of 0.3°C for temperature (T), 0.3 m/s for wind speed (Uz), 2% for relative humidity (RH), and 1 mb for pressure (P); 2) 0.0093 m for the aerodynamic roughness length (z0) based on z0 profiles calculations from multiple heights; and 3) 0.08 m for measurement height (z). Often z is held constant; here we used a constant z compared to the ground surface, and subsequently altered z to account for the change in snow depth (ds). The most important source of uncertainty was z0, then RH. Accounting for measurement height as it changed due to snowpack accumulation/ablation was also relevant for deeper snow. Snow surface sublimation uncertainties, from this study, are in the range of 1% to 29% for individual input parameter perturbations. The mean cumulative uncertainty was 41% for the three water years with 55%, 37%, and 32% occurring for the wet, average, and low water years. The top three variables (z varying with ds, z0, and RH) accounted for 74% to 84% of the cumulative sublimation uncertainty.

关键词： snow sublimation uncertainty aerodynamic methods

The role of p53 in developmental syndromes

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Journal of Molecular Cell Biology 2019年第3期11卷 200-211页

作者： Margot E.Bowen Laura d.Attardi division of Radiation and Cancer Biology in the department of Radiation Oncology Stanford University School of MedicineStanfordCA 94305USA department of Genetics Stanford University School of MedicineStanfordCA 94305USA

While it is well appreciated that loss of the p53 tumor suppressor protein promotes cancer,growing evidence indicates that increased p53 activity underlies the developmental defects in a wide range of genetic *** inherited or de novo mutations that cause these syndromes affect diverse cellular processes,such as ribosome biogenesis,dNA repair,and centriole duplication,and analysis of human patient samples and mouse models demonstrates that disrupting these cellular processes can activate the p53 ***,many of the developmental defects in mouse models of these syndromes can be rescued by loss of p53,indicating that inappropriate p53 activation directly contributes to their pathogenesis.A role for p53 in driving developmental defects is further supported by the observation that mouse strains with broad p53 hyperactivation,due to mutations affecting p53 pathway components,display a host of tissue-specific developmental defects,including hematopoietic,neuronal,craniofacial,cardiovascular,and pigmentation ***,germline activating mutations in TP53 were recently identified in two human patients exhibiting bone marrow failure and other developmental *** in mice suggest that p53 drives developmental defects by inducing apoptosis,restraining proliferation,or modulating other developmental programs in a cell type-dependent ***,we review the growing body of evidence from mouse models that implicates p53 as a driver of tissue-specific developmental defects in diverse genetic syndromes.

关键词： p53 Mdm2 development embryo congenital defect syndrome genetic disorder

γ-ray emission and pairs production in radiation pressure acceleration of colliding foils

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γ-ray emission and pairs production in radiation pressure a...

Modeling Pain Using fMRI:From Regions to Biomarkers

第十八届全国等离子体科学技术会议

作者： H.z.Li 余同普 College of Science National University of Defense Technology

Matter can be transferred into energy and the opposite transformation is also possible by using high-power *** photon-photon annihilation,a laser pulse can convert its energy intoγ-rays and then matter and antimatter,i.e.,e-e+*** of overdense e-e+pairs at Ge V energies usually requires extremely high laser *** we propose an all-optical scheme for ultra-brightγ-rays emission and dense positrons production by irradiating 10Wcm colliding lasers onto two diamondlike carbon *** electrons in the center area of the foil are rapidly accelerated by the laser radiation pressure,forming a flying relativistic plasma mirror,and collide with the other laser pulse which penetrates through the second foil from the other side due to the relativistically induced *** introducing the moving foil’s dynamics,this symmetric configuration enables efficient Compton back-scatterings and results in ultra-brightγ-photons emission with an unprecedented brightness of～10/ph/s/mm/mrad/0.1%BW at 15 MeV and intensityof *** firstthree-dimensionalparticle-in-cellsimulationwith quantumelectrodynamics(QEd)effects incorporated shows that a positron beam with a maximal density of 2.5×10cmand flux of 1.6×1010/shot at GeV energies is achieved and e-e+-plasma collective effects could be triggered,offering a new window on investigating QEd physics at PW laser facilities.

关键词： radiation pressure acceleration(RPA) QEd bright γ-ray emission electron positron pairs

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Neuroscience Bulletin 2018年第1期34卷 208-215页

作者： Marianne C.Reddan Tor d.Wager department of Psychology and Neuroscience University of Colorado Boulder

Pain is a subjective and complex phenomenon. Its complexity is related to its heterogeneity： multiple component processes, including sensation, affect, and cognition, contribute to pain experience and reporting. These components are likely to be encoded in distributed brain networks that interact to create pain experience and pain-related decision-making. Therefore, to understand pain, we must identify these networks and build models of these interactions that yield testable predictions about pain-related outcomes. We have developed several such models or ＇signatures＇ of pain, by （1） integrating activity across multiple systems, and （2） using pattern-recognition to identify processes related to pain experience. One model, the Neurologic Pain Signature, is sensitive and specific to pain in individuals, involves brain regions that receive nociceptive afferents, and shows little effect of expectation or self-regulation in tests to date. Another, the ＇Stimulus Intensity-Independent Pain Signature＇, explains substantial additional variation in trial-to-trial pain reports. It involves many brain regions that do not show increased activity in proportion to noxious stimulus intensity, includ- ing medial and lateral prefrontal cortex, nucleus accum- bens, and hippocampus. Responses in this system mediate expectancy and perceived control effects in several studies. Overall, this approach provides a pathway to understanding pain by identifying multiple systems that track different aspects of pain. Such componential models can be combined in unique ways on a subject-by-subject basis to explain an individual＇s pain experience.

关键词： Pain Biomarkers - fMRI - Models - Machine learning

The role of gut microbiota in the gut-brain axis:current challenges and perspectives

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Protein & Cell 2013年第6期4卷 403-414页

作者： Xiao Chen Roshan d’Souza Seong-Tshool Hong BdRd Research Institute JINIS Biopharmaceuticals Inc948-9 DunsanBongdongWanjuChonbuk 565-902South Korea department of Microbiology and Genetics and Institute for Medical Science Chonbuk National University Medical SchoolJeonju 561-712South Korea

Brain and the gastrointestinal(GI)tract are intimately con-nected to form a bidirectional neurohumoral communica-tion *** communication between gut and brain,knows as the gut-brain axis,is so well established that the functional status of gut is always related to the condi-tion of *** researches on the gut-brain axis were traditionally focused on the psychological status affecting the function of the GI ***,recent evidences showed that gut microbiota communicates with the brain via the gut-brain axis to modulate brain development and behavioral *** recent fi ndings on the new role of gut microbiota in the gut-brain axis implicate that gut microbiota could associate with brain functions as well as neurological diseases via the gut-brain *** elucidate the role of gut microbiota in the gut-brain axis,precise identification of the composition of microbes constituting gut microbiota is an essential ***,identifi cation of microbes constituting gut microbiota has been the main technological challenge currently due to massive amount of intestinal microbes and the diffi culties in culture of gut *** methods for identifi ca-tion of microbes constituting gut microbiota are depend-ent on omics analysis methods by using advanced high tech ***,we review the association of gut microbiota with the gut-brain axis,including the pros and cons of the current high throughput methods for identi-fi cation of microbes constituting gut microbiota to eluci-date the role of gut microbiota in the gut-brain axis.

关键词： gut microbiota the gut-brain axis central nervous system high throughput methods next-generation sequencings

Open and Closed： The Roles of Linker Histones in Plants and Animals

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Molecular Plant 2014年第3期7卷 481-491页

作者： Ryan S. Over Scott d. Michaels departments of Biology/Molecular and Cellular Biochemistry Indiana University 915 E. Third Street Bloomington IN 47405 USA

Histones package dNA in all eukaryotes and play key roles in regulating gene expression. Approximately 150 base pairs of dNA wraps around an octamer of core histones to form the nucleosome, the basic unit of chromatin. Linker histones compact chromatin further by binding to and neutralizing the charge of the dNA between nucleosomes. It is well established that chromatin packing is regulated by a complex pattern of posttranslational modifications （PTMs） to core histones, but linker histone function is less well understood. In this review, we describe the current understand- ing of the many roles that linker histones play in cellular processes, including gene regulation, cell division, and devel- opment, while putting the linker histone in the context of other nuclear proteins. Although intriguing roles for plant linker histones are beginning to emerge, much of our current understanding comes from work in animal systems. Many unanswered questions remain and additional work is required to fully elucidate the complex processes mediated by linker histones in plants.

关键词： linker histone histone H1 chromatin gene regulation development differentiation imprinting posttrans-lational modifications dNA methylation high mobility group proteins.

Artificial Neural Network （ANN） and Regression Tree （CART） applications for the indirect estimation of unsaturated soil shear strength parameters

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Frontiers of Earth Science 2014年第3期8卷 439-456页

作者： d.P. KANUNGO Shaifaly SHARMA Anindya PAIN Geotechnical Engineering Group CSIR - Central Building Research Institute (CBRI) Roorkee 247667 India

The shear strength parameters of soil （cohesion and angle of internal friction） are quite essential in solving many civil engineering problems. In order to determine these parameters, laboratory tests are used. The main objective of this work is to evaluate the potential of Artificial Neural Network （ANN） and Regression Tree （CART） techniques for the indirect estimation of these parameters. Four different models, considering different combinations of 6 inputs, such as gravel %, sand %, silt %, clay %, dry density, and plasticity index, were investigated to evaluate the degree of their effects on the prediction of shear parameters. A performance evaluation was carried out using Correlation Coefficient and Root Mean Squared Error measures. It was observed that for the prediction of friction angle, the performance of both the techniques is about the same. However, for the prediction of cohesion, the ANN technique performs better than the CART technique. It was further observed that the model considering all of the 6 input soil parameters is the most appropriate model for the prediction of shear parameters. Also, connection weight and bias analyses of the best neural network （i.e., 6/2/2） were attempted using Connec- tion Weight, Garson, and proposed Weight-bias approaches to characterize the influence of input variables on shear strength parameters. It was observed that the Connection Weight Approach provides the best overall methodology for accurately quantifying variable importance, and should be favored over the other approaches examined in this study.

关键词： cohesion friction angle Artificial NeuralNetwork Regression Tree Connection Weight Weight-bias Approach

Studies of the 2α and 3α channels of the ^(12)C+^(12)C reaction in the range of E_(c.m.)=8.9 MeV to 21 MeV using the active target Time Projection Chamber

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Chinese Physics C 2022年第10期46卷 116-125页

作者： X.Y.Wang N.T.zhang z.C.zhang C.G.Lu T.L.Pu J.L.zhang L.M.duan B.S.Gao K.A.Li Y.T.Li Y.Qian L.H.Ru B.Wang X.d.Xu H.Y.zhao W.P.Lin z.W.Cai B.F.Ji Q.T.Li J.Y.Xu X.d.Tang Joint department for nuclear physics Institute of Modern Physics and Lanzhou UniversityChinese Academy of SciencesLanzhou 730000China Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China School of Nuclear Science and Technology Lanzhou UniversityLanzhou 730000China School of Nuclear Science and Technology University of Chinese Academy of SciencesBeijing 100049China Key Laboratory of Radiation Physics and Technology of the Ministry of Education Institute of Nuclear Science and TechnologySichuan UniversityChengdu 610064China School of Physics and State Key Laboratory of Nuclear Physics and Technology Peking UniversityBeijing 100871China

The ^(12)C+^(12)C fusion reaction was studied in the range of E_(c.m.)=8.9 to 21 MeV using the active-target Time Projection *** full information on all tracks of the reaction products,cross sections of the^(12)C(^(12)C,^(8)Be)^(16)O_(g.s.)channel and the ^(12)C(^(12)C,3a)^(12)C channel could be measured down to the level of a few *** ^(12)C(^(12)C,^(8)Be)^(16)O_(g.s.)reaction channel was determined to be 10_(-8)^(+24) mb at E_(c.m.)=11.1 MeV,supporting the direct a transfer reaction *** ^(12)C(^(12)C,3α)^(12)C reaction channel was studied for the first time using an exclusive *** result does not confirm the anomaly behavior reported in the previous inclusive measurement by Kolata et al.[***.C 21,579(1980)].Our comparisons with statistical model calculations suggest that the 3 a channel is dominated by the fusion evaporation process at E_(c.m.)>19 *** additional contribution of the 3 a channel increases the fusion reaction cross section by 10% at energies above 20 *** also find that an additional reaction mechanism is needed to explain the measured cross section at E_(c.m.)del prediction vanishes.

关键词： fusion cross section Coulomb barrier Time Projection Chamber active target

Friedmann Cosmology with Bulk Viscosity:A Concrete Model for dark Energy

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Communications in Theoretical Physics 2009年第8期52卷 377-382页

作者： MENG Xin-He d0U Xu department of Physics Nankai University Tianjin 300071 China Kavli Institute for Theoretical Physics China at the Chinese Academy of Sciences （KITPC-CAS） Beijing 100190 China

The universe content is considered as a non-perfect fluid with bulk viscosity and can be described by a general equation of state （endowed some deviation from the conventionally assumed cosmic perfect fluid model）. An explicitly bulk viscosity dark energy model is proposed to confront consistently with the current observational data sets by statistical analysis and is shown consistent with （not deviated away much from） the concordant A Cold dark Matter （CdM） model by comparing the decelerating parameter. Also we compare our relatively simple viscosity dark energy model with a more complicated one by contrast with the concordant ACdM model and find our model improves for the viscosity dark energy model building. Finally we discuss the perspectives of dark energy probes for the coming years with observations.

关键词： dark energy cosmology bulk viscosity unification of dark matter and dark energy