Mechanistic Modeling of Microtopographic Impacts on CO2 and CH4 Fluxes in an Alaskan Tundra Ecosystem Using the CLM-Microbe Model

Spatial heterogeneities in soil hydrology have been confirmed as a key control on CO2 and CH4 fluxes in the Arctic tundra ecosystem. In this study, we applied a mechanistic ecosystem model, CLM-Microbe, to examine the microtopographic impacts on CO2 and CH4 fluxes across seven landscape types in Utqiaġvik, Alaska: trough, low-centered polygon (LCP) center, LCP transition, LCP rim, high-centered polygon (HCP) center, HCP transition, and HCP rim. We first validated the CLM-Microbe model against static-chamber measured CO2 and CH4 fluxes in 2013 for three landscape types: trough, LCP center, and LCP rim. Model application showed that low-elevation and thus wetter landscape types (i.e., trough, transitions, and LCP center) had larger CH4 emissions rates with greater seasonal variations than high-elevation and drier landscape types (rims and HCP center). Sensitivity analysis indicated that substrate availability for methanogenesis (acetate, CO2 + H2) is the most important factor determining CH4 emission, and vegetation physiological properties largely affect the net ecosystem carbon exchange and ecosystem respiration in Arctic tundra ecosystems. Modeled CH4 emissions for different microtopographic features were upscaled to the eddy covariance (EC) domain with an area-weighted approach before validation against EC-measured CH4 fluxes. The model underestimated the EC-measured CH4 flux by 20% and 25% at daily and hourly time steps, suggesting the importance of the time step in reporting CH4 flux. The strong microtopographic impacts on CO2 and CH4 fluxes call for a model-data integration framework for better understanding and predicting carbon flux in the highly heterogeneous Arctic landscape

Pedestrian Trajectory Prediction with Structured Memory Hierarchies

This paper presents a novel framework for human trajectory prediction based on multimodal data (video and radar). Motivated by recent neuroscience discoveries, we propose incorporating a structured memory component in the human trajectory prediction pipeline to capture historical information to improve performance. We introduce structured LSTM cells for modelling the memory content hierarchically, preserving the spatiotemporal structure of the information and enabling us to capture both short-term and long-term context. We demonstrate how this architecture can be extended to integrate salient information from multiple modalities to automatically store and retrieve important information for decision making without any supervision. We evaluate the effectiveness of the proposed models on a novel multimodal dataset that we introduce, consisting of 40,000 pedestrian trajectories, acquired jointly from a radar system and a CCTV camera system installed in a public place. The performance is also evaluated on the publicly available New York Grand Central pedestrian database. In both settings, the proposed models demonstrate their capability to better anticipate future pedestrian motion compared to existing state of the art.Comment: To appear in ECML-PKDD 201

On the Kinematic Signature of the Galactic Warp As Revealed by the LAMOST-TGAS Data

Using a sample of about 123,000 stars with accurate 3D velocity measurements from the LAMOST-TGAS data, we confirm the kinematic signature of the Galactic warp recently found by Schonrich & Dehnen. The data reveal a clear trend of increasing mean vertical velocity Vz as a function of absolute vertical angular momentum Lz and azimuthal velocity Vφ for guiding center radius Rg between 6.0 and 10.5 kpc. The trend is consistent with a largescale Galactic warp. Similar to Schonrich & Dehnen, we also find a wave-like pattern of Vz versus Lz with an amplitude of ∼0.9 km s-1 on a scale of ∼2.0 kpc, which could arise from bending waves or a winding warp. Finally, we confirm a prominent, localized peak in Vz near Lz ∼ 2150 kpc km s-1 (corresponding to Rg ∼ 9 kpc and Vφ ∼ 255 km s-1). The additional line-of-sight velocity information from LAMOST reveals that stars in this feature have a large, inward radial velocity of VR ∼ -13.33 ± 0.59 km s-1 and a small radial velocity dispersion of σR ∼ 25.27 ± 0.89 km s-1, suggesting that a stellar stream gives rise to this feature

Higgs boson enhancement effects on squark-pair production at the LHC

We study the Higgs boson effects on third-generation squark-pair production in proton-proton collision at the CERN Large Hadron Collider (LHC), including \Stop \Stop^*, \Stop\Sbot^*, and \Sbot \Sbot^*. We found that substantial enhancement can be obtained through s-channel exchanges of Higgs bosons at large $\tan\beta$, at which the enhancement mainly comes from $b\bar b$, $b\bar c$, and $c\bar b$ initial states. We compute the complete set of electroweak (EW) contributions to all production channels. This completes previous computations in the literature. We found that the EW contributions can be significant and can reach up to 25% in more general scenarios and at the resonance of the heavy Higgs boson. The size of Higgs enhancement is comparable or even higher than the PDF uncertainties and so must be included in any reliable analysis. A full analytical computation of all the EW contributions is presented.Comment: 23 pages, 7 figures, 1 tabl

The effect of cigarette price increase on the cigarette consumption in Taiwan: evidence from the National Health Interview Surveys on cigarette consumption

BACKGROUND: This study uses cigarette price elasticity to evaluate the effect of a new excise tax increase on cigarette consumption and to investigate responses from various types of smokers. METHODS: Our sample consisted of current smokers between 17 and 69 years old interviewed during an annual face-to-face survey conducted by Taiwan National Health Research Institutes between 2000 to 2003. We used Ordinary Least Squares (OLS) procedure to estimate double logarithmic function of cigarette demand and cigarette price elasticity. RESULTS: In 2002, after Taiwan had enacted the new tax scheme, cigarette price elasticity in Taiwan was found to be -0.5274. The new tax scheme brought about an average annual 13.27 packs/person (10.5%) reduction in cigarette consumption. Using the cigarette price elasticity estimate from -0.309 in 2003, we calculated that if the Health and Welfare Tax were increased by another NT$ 3 per pack and cigarette producers shifted this increase to the consumers, cigarette consumption would be reduced by 2.47 packs/person (2.2%). The value of the estimated cigarette price elasticity is smaller than one, meaning that the tax will not only reduce cigarette consumption but it will also generate additional tax revenues. Male smokers who had no income or who smoked light cigarettes were found to be more responsive to changes in cigarette price. CONCLUSIONS: An additional tax added to the cost of cigarettes would bring about a reduction in cigarette consumption and increased tax revenues. It would also help reduce incidents smoking-related illnesses. The additional tax revenues generated by the tax increase could be used to offset the current financial deficiency of Taiwan's National Health Insurance program and provide better public services

Are voltage-gated sodium channels on the dorsal root ganglion involved in the development of neuropathic pain?

Neuropathic pain is a common clinical condition. Current treatments are often inadequate, ineffective, or produce potentially severe adverse effects. Understanding the mechanisms that underlie the development and maintenance of neuropathic pain will be helpful in identifying new therapeutic targets and developing effective strategies for the prevention and/or treatment of this disorder. The genesis of neuropathic pain is reliant, at least in part, on abnormal spontaneous activity within sensory neurons. Therefore, voltage-gated sodium channels, which are essential for the generation and conduction of action potentials, are potential targets for treating neuropathic pain. However, preclinical studies have shown unexpected results because most pain-associated voltage-gated channels in the dorsal root ganglion are down-regulated after peripheral nerve injury. The role of dorsal root ganglion voltage-gated channels in neuropathic pain is still unclear. In this report, we describe the expression and distribution of voltage-gated sodium channels in the dorsal root ganglion. We also review evidence regarding changes in their expression under neuropathic pain conditions and their roles in behavioral responses in a variety of neuropathic pain models. We finally discuss their potential involvement in neuropathic pain

Strain- and Adsorption-Dependent Electronic States and Transport or Localization in Graphene

The chapter generalizes results on influence of uniaxial strain and adsorption on the electron states and charge transport or localization in graphene with different configurations of imperfections (point defects): resonant (neutral) adsorbed atoms either oxygen- or hydrogen-containing molecules or functional groups, vacancies or substitutional atoms, charged impurity atoms or molecules, and distortions. To observe electronic properties of graphene-admolecules system, we applied electron paramagnetic resonance technique in a broad temperature range for graphene oxides as a good basis for understanding the electrotransport properties of other active carbons. Applied technique allowed observation of possible metal-insulator transition and sorption pumping effect as well as discussion of results in relation to the granular metal model. The electronic and transport properties are calculated within the framework of the tight-binding model along with the Kubo-Greenwood quantum-mechanical formalism. Depending on electron density and type of the sites, the conductivity for correlated and ordered adsorbates is found to be enhanced in dozens of times as compared to the cases of their random distribution. In case of the uniaxially strained graphene, the presence of point defects counteracts against or contributes to the band-gap opening according to their configurations. The band-gap behaviour is found to be nonmonotonic with strain in case of a simultaneous action of defect ordering and zigzag deformation. The amount of localized charge carriers (spins) is found to be correlated with the content of adsorbed centres responsible for the formation of potential barriers and, in turn, for the localization effects. Physical and chemical states of graphene edges, especially at a uniaxial strain along one of them, play a crucial role in electrical transport phenomena in graphene-based materials.Comment: 16 pages, 10 figure

On the selection and design of proteins and peptide derivatives for the production of photoluminescent, red-emitting gold quantum clusters

Novel pathways of the synthesis of photoluminescent gold quantum clusters (AuQCs) using biomolecules as reactants provide biocompatible products for biological imaging techniques. In order to rationalize the rules for the preparation of red-emitting AuQCs in aqueous phase using proteins or peptides, the role of different organic structural units was investigated. Three systems were studied: proteins, peptides, and amino acid mixtures, respectively. We have found that cysteine and tyrosine are indispensable residues. The SH/S-S ratio in a single molecule is not a critical factor in the synthesis, but on the other hand, the stoichiometry of cysteine residues and the gold precursor is crucial. These observations indicate the importance of proper chemical behavior of all species in a wide size range extending from the atomic distances (in the AuI-S semi ring) to nanometer distances covering the larger sizes of proteins assuring the hierarchical structure of the whole self-assembled system

); fax 886-4-2236-1230; hylane@gmail

The WCST, a widely used measure of prefrontal cognitive functions (including executive function, abstraction and working memory), is sensitive to a person's ability to generate hypotheses, establish response sets and fluently shift sets. 9,10 A recent meta-analysis 11 suggests that there is a small but significant relation between Val158Met genotype and WCST performance in healthy people but not in those with schizophrenia. Because the COMT Val158Met polymorphism accounts for a small portion of the variability in prefrontal cognition, it is warranted to explore whether other genetic mutations have potential effects. Of dopamine receptors, D 1 and D 3 may deserve foremost attention. D 1 receptors play a critical role in the activation of prefrontal cognition such as working memory. 3 In addition, D 1 activation modulates rodents' social cognition, 13 which depends substantially on prefrontal function. 14 Among genetic variants of D 1 receptors, the A-48G polymorphism is associated with glucose metabolic rates in human brain regions, including the prefrontal cortex. 15 The D 3 receptor, although structurally highly homologous to other D 2 -like dopamine receptors, differs from them in regulating neuropsychological performance. 6 D 2 may also regulate spatial working memory, but the latter is principally attributed to D 1 receptor-mediated mechanisms. 22 By interacting with the dopaminergic system, serotonergic transmission also plays a significant role in prefrontal cognitive function. 23 Its action is mediated via specific receptors, possibly serotonin 5-HT 2A and 5-HT 6 , located in crucial brain structures, primarily the nucleus basalis magnocellularisfrontal cortex. In rats, 5-HT 2A receptors regulate prefrontal cortex-related execution of primed responses. 3 In healthy volunteers, 5-HT 2A agonists impair the continuous performance task, 24 which is mainly determined by prefrontal function. 25 Among 5-HT 2A receptor polymorphisms, T102C has received considerable attention. For instance, this genetic variance affects treatment response to antipsychotics. The 5-HT 6 receptor is responsible for endogenous 5-HT-mediated facilitation of dopamine release in the rat prefrontal cortex 30 and regulates brain cholinergic neurotransmission. 31,32 It has been indicated that, among 5-HT 6 receptor polymorphisms, 33 T267C is associated with Alzheimer disease. 35 The current study aims to explore the effects of the aforementioned genetic variances of D 1 , D 3 , 5-HT 2A and 5-HT 6 on WCST performance, which reflects prefrontal executive function, in a healthy population. Methods Participants This study was approved by the institutional review board of China Medical University Hospital and carried out in accordance with the Declaration of Helsinki (www.wma.net /e/policy/b3.htm). The participants were 216 unrelated healthy volunteers (81 men and 135 women) with a mean age of 48.6 (standard deviation [SD] 9.4) years (range 20-65 y) and a mean education level of 10.9 (SD 3.7) years (range 0-20 y). All were Han Chinese living in Taiwan. The subjects in this study gave their consent to participate after procedures were explained to them. All subjects were free of any axis I or II psychiatric disorders, as determined by a research psychiatrist using the Structured Clinical Interview for DSM-IV. WCST assessments An experienced psychologist (Y-LC) administered the WCST. Genotyping Genomic DNA was extracted from the subjects' white blood cells. The 4 polymorphisms were genotyped according to the polymerase chain reaction-restriction fragment length polymorphism technique. Forward and reverse primers and restriction enzymes for each polymorphism were as follows: 5′-ACT GAC CCC TAT TCC CTG CT-3′, 5′-AGC ACA GAC CAG CGT GTT C-3′, DdeI for A-48G polymorphisms in the promoter region of the dopamine D 1 receptor gene; 38 5′-GCT CTA TCT CCA ACT CTC ACA-3′, 5′-AAG TCT ACT CAC CTC CAG GTA-3′, MscΙ for the D 3 Ser9Gly polymorphism; 39,40 5′-TCT GCT ACA AGT TCT GGC TT-3′, 5′-CTG CAG CTT TTT CTC TAG GG-3′, MspI for 5-HT 2A T102C; 41,42 and 5′-AAC TTC TTC CTG GTG TCG CTC TTC-3′, 5′-ATG AGC AGG TAG CGG TCC AGG-3′, RsaI for T267C polymorphisms in the 5-HT 6 receptor gene. Data analyses We used a 2-tailed Mann-Whitney U test for WCST performance comparisons between male and female subjects. Kruskal-Wallis tests were carried out with each genetic polymorphism as the independent variable and percentage of perseverative errors and number of categories as the dependent measures. These nonparametric statistical methods were used because the distributions of perseverative errors and categories numbers were skewed to the right (data not shown). We also compared the subjects' demographic characteristics among genotypes of each genetic polymorphism, using Kruskal-Wallis tests for continuous variables and χ 2 tests for categorical variables. Statistical significance was defined as p < 0.05 or corrected for multiple comparisons as needed (p < 0.0125 = 0.05/4 [genetic polymorphisms]). To control for the effects of other confounding factors, we used multiple linear regression in a single analysis to evaluate impacts of sex, age, sex × age interaction, education level and the 4 genetic polymorphisms simultaneously on WCST performance. Because all these comparisons were performed in a single multiple regression analysis, no correction for multiple comparisons was required. However, the distributions of the WCST data were skewed to the right and unsuitable for regression analyses. To convert the skewed distribution to a normal one, we measured each perseverative error value in its natural logarithmic scale before the regression analysis. 44,45 Results In all 216 subjects, the mean percentage of WCST perseverative errors was 20.1% (SD 13.1%) and the mean number of WCST categories completed was 4.18 (SD 3.08). Men and women had comparable mean perseverative errors at 18.7 (SD 12.0) and 20.9 (SD 13.8) (p = 0.46), respectively, and comparable mean numbers of categories completed at 4.4 (SD 3.2) and 4.1 (SD 3.0) (p = 0.55). Allele frequencies of the genetic polymorphisms in our Han Chinese sample are similar to those in other Han Chinese populations but may be different from those in white populations WCST perseverative errors and genotype

Macrocyclic colibactin induces DNA double-strand breaks via copper-mediated oxidative cleavage.

Colibactin is an assumed human gut bacterial genotoxin, whose biosynthesis is linked to the clb genomic island that has a widespread distribution in pathogenic and commensal human enterobacteria. Colibactin-producing gut microbes promote colon tumour formation and enhance the progression of colorectal cancer via cellular senescence and death induced by DNA double-strand breaks (DSBs); however, the chemical basis that contributes to the pathogenesis at the molecular level has not been fully characterized. Here, we report the discovery of colibactin-645, a macrocyclic colibactin metabolite that recapitulates the previously assumed genotoxicity and cytotoxicity. Colibactin-645 shows strong DNA DSB activity in vitro and in human cell cultures via a unique copper-mediated oxidative mechanism. We also delineate a complete biosynthetic model for colibactin-645, which highlights a unique fate of the aminomalonate-building monomer in forming the C-terminal 5-hydroxy-4-oxazolecarboxylic acid moiety through the activities of both the polyketide synthase ClbO and the amidase ClbL. This work thus provides a molecular basis for colibactin's DNA DSB activity and facilitates further mechanistic study of colibactin-related colorectal cancer incidence and prevention