bluuebunny/crossref_metadata_2025 huggingface dataset:
ChemInform Abstract: COBALT(II), NICKEL(II), AND COPPER(II) NITRATE COMPLEXES WITH PYRAZINE N‐OXIDE
Authors: SPECA A. N. , KARAYANNIS N. M. , PYTLEWSKI L. L. , OWENS C.
Published: March 2016

Die Umsetzung von Pyrazin‐N‐oxid mit 3d‐Metallnitraten liefert die Verbindungen (I) und (II).
ChemInform Abstract: SPECTROSCOPIC STUDY OF THE EQUILIBRIUM OF ADDUCT FORMATION BY ACETYLACETONATES OF OXOVANADIUM(IV) AND COPPER(II) WITH NITROGEN BASES
Authors: KWIATKOWSKI E. , TROJANOWSKI J.
Published: March 2016

Es werden die Gleichgewichtskonstanten der 1:1‐Adduktbildung mit 30 N‐Basen wie z.B. Amine, Chinoline und Pyridine in Methylenchlorid bestimmt.
ChemInform Abstract: Stabile Cu(III) Complex Prepared.
Authors: MARGERUM D. W.
Published: March 2016

Nach Untersuchungen an der Purdue Univ., W. Lafayette, werden Cu(II)‐Ionen, die mit deprotonierten Amiden oder Peptiden komplexiert sind, unter Bildung von Cu(III)‐Komplexen oxidiert.
ChemInform Abstract: CATALYSIS BY METAL COMPLEXES. XXXIV. CATALYTIC ACTIVITY OF RHODIUM(I) COMPLEXES IN HYDROSILYLATION OF ALKENES
Authors: REJHON J. , HETFLEJS J.
Published: March 2016

Die katalytische Aktivität einer Reihe von Rh(I)‐phosphin‐ und ‐phosphit‐Komplexen bei der Hydrosilylierung von Hexen‐(1) und von Styrol unter Bildung von l‐silyliertem Hexan bzw. 1‐ und 2‐silyliertem Phenyläthan wird untersucht.
ChemInform Abstract: SULFUR DIOXIDE INSERTIONS INTO PALLADIUM AND PLATINUM‐OXYGEN BONDS
Authors: ROS RENZO , CARTURAN GIOVANNI , GRAZIANI MAURO
Published: March 2016

In Methanol, Äthanol oder n‐Propanol suspendierte Pd(II)‐halogenide reagieren mit SO2 zu Zweikernkomplexen, die als Tetraphenylarsonium‐ und ‐phosphonium‐Salze (I) isoliert werden.
ChemInform Abstract: ENOL DERIVATIVES OF THE CHLOROPHYLL SERIES. PREPARATION OF 132,173‐CYCLOPHEOPHORBIDE ENOLS
Authors: FALK HEINZ , HOORNAERT GEORGES , ISENRING HANS‐PETER , ESCHENMOSER ALBERT
Published: March 2016

Die Titelverbindungen (II), (IV) und (VI) werden als Modellsysteme für Untersuchungen des Einflusses der Enolisierung des E‐Ringes auf die Eigenschaften von Chlorophyllderivaten dargestellt.
ChemInform Abstract: New Chemical Route to Pure L‐Lysine.
Authors: SIFNIADES S.
Published: March 2016

Eine übersättigte Lösung des α‐Aminocaprolactam‐Nickel‐Komplexes (I) wird durch Umsetzung von DL‐Aminocaprolactam mit Nickel(II)‐chlorid in siedendem Äthanol in Gegenwart von Nickeläthylat hergestellt.
ChemInform Abstract: AMINO SUGARS. XXXIII. PREPARATION OF SOME METHYL 3‐ACETAMIDO‐3,6‐DIDEOXY‐β‐D‐HEXOPYRANOSIDES
Authors: CAPEK K. , STANEK J. JUN. , CAPKOVA J. , JARY J.
Published: March 2016

Die Azidolyse des Galaktopyranosids (I) führt zum Glucosederivat (II), das als Diacetat isoliert wird, und zum Gulosederivat (IIIa), das mittels katalytischer Hydrierung in den Aminozucker (IIIb) übergeführt wird.
ChemInform Abstract: SYNTHESIS OF FLUORINATED BRANCHED‐CHAIN SUGARS
Authors: BISCHOFBERGER KARL , BRINK ABRAHAM J. , JORDAAN AMOR
Published: March 2016

Die Reaktion der Glucofuranose (I) mit Fluoroxy‐trifluormethan in reinem CHQCI, gibt den Iminoester (IIa) und in Gegenwart von Spuren Wasser und Äthanol den Ketoester (IIb) und den Äthoxyester (III).
ChemInform Abstract: CONSTITUENTS OF EUPOMATIA SPECIES. IV. STRUCTURE AND SYNTHESIS OF EUPOLAURIDINE (EL BASE‐1) AND SOME OBSERVATIONS ON THE STRUCTURES OF EUPOLAURAMINE (EL BASE‐2) AND HYDROXYEUPOLAURAMINE (EL BASE‐3)
Authors: BOWDEN BRUCE F. , PICKER KELVIN , RITCHIE ERNEST , TAYLOR WALTER C.
Published: March 2016

Eupolauridin (EL Base‐1) besitzt die Struktur (Vc) und nicht, wie aufgrund spektroskopischer Untersuchungsergebnisse zunächst ebenfalls möglich erscheint, die isomere Struktur (IXc).
ChemInform Abstract: 5‐ALLYL‐9‐OXOBENZOMORPHANS. 2. CRYSTAL AND MOLECULAR STRUCTURE OF AN UNUSUAL PRODUCT OF DEQUATERNIZATION OF 5‐ALLYL‐9‐OXOBENZOMORPHAN METHOBROMIDE
Authors: AHMED FARID R. , SAUCIER MICHEL , MONKOVIC IVO
Published: March 2016

Die der in der l. Mitt. beschriebenen Synthese von (VIa) analog verlaufende Synthese des Benzomorphanons (VIb) aus dem Tetralon (Ib) über die Stufen (IIb) bis (Vb) wird beschrieben.
ChemInform Abstract: REACTIONS OF CYTOSINE AND CYTIDINE WITH O‐SUBSTITUTED HYDROXYLAMINES
Authors: SCHALKE PETER M. , HALL C. DENNIS
Published: March 2016

Bei der Reaktion von Cytosin (Ia) oder Cytidin (Ib) mit einem Überschuß des Hydroxylamins (II) in Methanol‐Wasser bei einem pH‐Wert von 4‐5 erfolgt Substitution und Addition zu den Cytosinderivaten (III).
ChemInform Abstract: SYNTHESIS OF TRITIUM‐LABELED JUVENILE‐HORMONE‐EFFICIENT 10,11‐EPOXY‐6,7‐TRANS‐2,3‐TRANS‐FARNESYL 2‐PROPENYL ETHER WITH VERY HIGH SPECIFIC RADIOACTIVITY
Authors: SCHMIALEK P.
Published: March 2016

Aus Famesylbromid (I) und dem Na‐alkoholat (II) wird der Äther (III) dargestellt, der zu dem Epoxid (IV) oxidiert wird.
Relative Stereochemistry and Absolute Configuration of Farinosin, a Eudesmanolide From Encelia farinosa
Authors: Ortega Alfredo R. , Sánchez‐Castellanos Mariano , Pérez‐Hernández Nury , Robles‐Zepeda Ramón E. , Joseph‐Nathan Pedro , Quijano Leovigildo
Published: March 2016

The naturally occurring eudesmanolide farinosin (1) is now fully characterized for the first time despite its original isolation almost half a century ago. The early assumed relative stereochemistry and absolute configuration were confirmed by vibrational circular dichroism together with evaluation of the Hooft X‐ray parameters. The molecular conformation is very similar in the gas stage and in the solid state. Chirality 28:415–419, 2016. © 2016 Wiley Periodicals, Inc.
Nanostructure Architectures of Tungsten Carbide for Methanol Electrooxidation Catalyst
Authors: Jiang Yekun , Shi Meiqin , Tong Xue , Chu Youqun , Ma Chunan
Published: March 2016

We reported a novel protocol to efficiently synthesize tungsten carbide (WC) nanomaterials with pure crystal structure and certain specific morphology. The key step in this protocol is the preparation of the catalyst precursor W18O49 with surface oxygen vacancies. The existence of large quantities of oxygen vacancies gives plenty channels for diffusion and keeps the specific morphology of WC in the carbonization process. Efforts to build WC blocks with well‐defined geometrical shapes (e.g., rods, wires, spheres and flakes) have further expanded its possibility to be the support for methanol electrooxidation catalyst. The platinum supported on pure phase WC materials served as an effective CO tolerant electrocatalyst for methanol oxidation. Electrochemical experiments indicated that the improved catalytic activity was related to the special morphologies of WC supports. Its sea urchin like feature leads to substantial interfaces between WC and Pt by preparing more anchor points for Pt loading and also the barriers for the subsequent crystal growth, which enhances the synergistic effect between WC and Pt.
Cadmium–Aluminum Layered Double Hydroxide Microspheres for Photocatalytic CO2 Reduction
Authors: Saliba Daniel , Ezzeddine Alaa , Sougrat Rachid , Khashab Niveen M. , Hmadeh Mohamad , Al‐Ghoul Mazen
Published: March 2016

We report the synthesis of cadmium–aluminum layered double hydroxide (CdAl LDH) using the reaction‐diffusion framework. As the hydroxide anions diffuse into an agar gel matrix containing the mixture of aluminum and cadmium salts at a given ratio, they react to give the LDH. The LDH self‐assembles inside the pores of the gel matrix into a unique spherical‐porous shaped microstructure. The internal and external morphologies of the particles are studied by electron microscopy and tomography revealing interconnected channels and a high surface area. This material is shown to exhibit a promising performance in the photoreduction of carbon dioxide using solar light. Moreover, the palladium‐decorated version shows a significant improvement in its reduction potential at room temperature.
Dynamic joint model of capacitive charge pumps and on‐chip photovoltaic cells for CMOS micro‐energy harvesting
Authors: Ferro Esteban , López Paula , Brea Víctor Manuel , Cabello Diego
Published: March 2016

On‐chip energy harvesting by means of integrated photovoltaic cells in standard CMOS technology can be successfully used to recharge or power‐up integrated circuits with the use of charge pumps for voltage boosting. In this paper, a tool to facilitate the design of such structures is proposed consisting of an accurate model of the joint dynamics of the micro‐photovoltaic cell and a capacitive DC/DC converter in the slow‐switching limit regime. The model takes into account both the top and bottom parasitic capacitances of the flying capacitors. We assume a classical model for the photodiode whose photogenerated current is extracted from device‐level simulations. The joint model is verified by circuit‐level simulations achieving high accuracy and computation time savings of up to 1700×. The joint model shows that the voltage generated by an integrated photovoltaic cell connected to a capacitive DC/DC converter is not constant even under constant illumination. This phenomenon can only be reproduced through the joint model and failing to take it into account results in an error in the estimation of the time needed by the DC/DC converter to reach a given output voltage. We also demonstrate that the maximum output voltage reached by a DC/DC converter in the slow‐switching limit regime when a photovoltaic cell is used as energy transducer depends on the switching frequency. Finally, the applicability of the model is illustrated through the optimization of time response and charge efficiency for the Dickson, Fibonacci, and exponential topologies in the case of implantable devices. Copyright © 2016 John Wiley & Sons, Ltd.
Mowing strategies for controlling Cirsium arvense in a permanent pasture in New Zealand compared using a matrix model
Authors: Bourdôt Graeme W. , Basse Britta , Cripps Michael G.
Published: March 2016

Defoliation has frequently been proposed as a means of controlling Cirsium arvense (L.) Scop. (Californian thistle, Canada thistle, creeping thistle, perennial thistle), an economically damaging pastoral weed in temperate regions of the world, but its optimization has remained obscure. We developed a matrix model for the population dynamics of C. arvense in sheep‐grazed pasture in New Zealand that accounts for the effects of aerial shoot defoliation on a population's photosynthetic opportunity and consequential overwintered root biomass, enabling mowing regimes varying in the seasonal timing and frequency of defoliation to be compared. The model showed that the long‐term population dynamics of the weed is influenced by both the timing and frequency of mowing; a single‐yearly mowing, regardless of time of year, resulted in stasis or population growth, while in contrast, 14 of 21 possible twice‐yearly monthly mowing regimes, mainly those with mowing in late spring, summer, and early autumn, resulted in population decline. Population decline was greatest (with population density halving each year) with twice‐yearly mowing either in late spring and late summer, early summer and late summer, or early summer and early autumn. Our results indicate that mowing can be effective in reducing populations of C. arvense in pasture in the long term if conducted twice each year when the initial mowing is conducted in mid spring followed by a subsequent mowing from mid summer to early autumn. These mowing regimes reduce the photosynthetic opportunity of the C. arvense population and hence its ability to form the overwintering creeping roots upon which population growth depends.
Internal concentration as a better predictor of metal toxicity than the fractional coverage of metals on biotic ligand: Comparison of 3 modeling approaches
Authors: Gao Yongfei , Feng Jianfeng , Zhu Lin
Published: March 2016

Modeling toxicity of metal mixtures poses unique challenges to the incorporation of bioavailability and metal speciation in metal exposures. Three models (models I, II, and III) were compared in the present study to predict and interpret the toxicity exerted by binary metal mixtures to zebrafish larvae, with the assumption of competition between metals based on the biotic ligand model and toxic potencies of individual metals. In addition, 3 models were developed by substituting binding constants (fMBL) for internal metal concentrations (CM,int) to directly delineate single-metal and mixture effects on mortality of zebrafish larvae. The results indicated that the 3 developed models appeared to be much better (p < 0.01) than 3 previous models at assessing the toxicity of different metal mixtures and showed 10% to 20% predictive improvement for each metal combination, with the toxic equivalency factor–based model II showing the best performance at quantifying metal mixture toxicity. The 3 developed models generally provided a reasonable framework and descriptions of bioavailability and additive (or nearly additive) toxicity for a number of binary metal mixtures. Environ Toxicol Chem 2016;35:2721–2733. © 2016 SETAC
Glyphosate and aminomethylphosphonic acid chronic risk assessment for soil biota
Authors: von Mérey Georg , Manson Philip S. , Mehrsheikh Akbar , Sutton Peter , Levine Steven L.
Published: March 2016

Glyphosate is a broad-spectrum herbicide used widely in agriculture, horticulture, private gardens, and public infrastructure, where it is applied to areas such as roadsides, railway tracks, and parks to control the growth of weeds. The exposure risk from glyphosate and the primary soil metabolite aminomethylphosphonic acid (AMPA) on representative species of earthworms, springtails, and predatory soil mites and the effects on nitrogen-transformation processes by soil microorganisms were assessed under laboratory conditions based on internationally recognized guidelines. For earthworms, the reproductive no-observed-effect concentration (NOEC) was 472.8 mg glyphosate acid equivalent (a.e.)/kg dry soil, which was the highest concentration tested, and 198.1 mg/kg dry soil for AMPA. For predatory mites, the reproductive NOEC was 472.8 mg a.e./kg dry soil for glyphosate and 320 mg/kg dry soil for AMPA, the highest concentrations tested. For springtails, the reproductive NOEC was 472.8 mg a.e./kg dry soil for glyphosate and 315 mg/kg dry soil for AMPA, the highest concentrations tested. Soil nitrogen-transformation processes were unaffected by glyphosate and AMPA at 33.1 mg a.e./kg soil and 160 mg/kg soil, respectively. Comparison of these endpoints with worst-case soil concentrations expected for glyphosate (6.62 mg a.e./kg dry soil) and AMPA (6.18 mg/kg dry soil) for annual applications at the highest annual rate of 4.32 kg a.e./ha indicate very low likelihood of adverse effects on soil biota. Environ Toxicol Chem 2016;35:2742–2752. © 2016 The Authors. Environmental Toxicology and Chemistry Published by Wiley Periodicals, Inc. on behalf of SETAC.
An Investigation of the Use and Predictive Validity of Scores From the GRE® revised General Test in a Singaporean University
Authors: Liu Ou Lydia , Klieger David M. , Bochenek Jennifer L. , Holtzman Steven L. , Xu Jun
Published: March 2016

International institutions have been increasingly using the GRE® revised General Test to admit students to graduate programs. However, little is known about how scores from the GRE revised General Test are used in the admission process outside of the United States and their validity in predicting graduate students' performance (e.g., their graduate school grade point averages [GGPAs]). As the GRE revised General Test was launched in August 2011, there is a compelling need to investigate its predictive validity, particularly in an international context. A large percentage of examinees who take the GRE revised General Test from outside of the United States are citizens of Asian countries. Consequently, we examined how scores from the GRE revised General Test predict a range of graduate student performance outcomes at a Singaporean institution that represents the highest caliber of academic excellence in Asian countries. We also interviewed key members of the admissions committees to understand how the GRE revised General Test and its individual sections are used in the admission process. Our analyses revealed that scores from the GRE revised General Test predicted GGPA and program standing. In particular, these scores showed incremental value beyond undergraduate GPA (UGPA) for predicting GGPA. Furthermore, among enrolled students, those who submitted scores from the GRE revised General Test in application had significantly higher GGPAs than those who did not. These findings largely apply to both doctoral and master's students.
An event simulation approach to the assessment of flood level frequencies: risk maps for the Warsaw reach of the River Vistula
Authors: Romanowicz R. J. , Kiczko A.
Published: March 2016

Flood risk assessment is customarily performed using a design flood. Observed past flows are used to derive a flood frequency curve which forms the basis for a construction of a design flood. The simulation of a distributed model with the 1‐in‐T year design flood as an input gives information on the possible inundation areas, which are used to derive flood risk maps. The procedure is usually performed in a deterministic fashion, and its extension to take into account the design flood‐and flow routing model uncertainties is computer time consuming. In this study we propose a different approach to flood risk assessment which consists of the direct simulation of a distributed flow routing model for an observed series of annual maximum flows and the derivation of maps of probability of inundation of the desired return period directly from the obtained simulations of water levels at the model cross sections through an application of the Flood Level Frequency Analysis. The hydraulic model and water level quantile uncertainties are jointly taken into account in the flood risk uncertainty evaluation using the Generalized Likelihood Uncertainty Estimation (GLUE) approach. An additional advantage of the proposed approach lies in smaller uncertainty of inundation predictions for long return periods compared to the standard approach. The approach is illustrated using a design flood level and a steady‐state solution of a hydraulic model to derive maps of inundation probabilities. Copyright © 2016 John Wiley & Sons, Ltd.
TET2 regulates LncRNA‐ANRIL expression and inhibits the growth of human gastric cancer cells
Authors: Deng Wei , Wang Jin , Zhang Jun , Cai Jun , Bai Zhigang , Zhang Zhongtao
Published: March 2016

Ten‐eleven translocation (TET) family enzymes convert 5‐methylcytosine to 5‐hydroxymethylcytosine in DNA. However, the role of TET enzymes in human gastric cancer remains unknown. Here, we show that TET2 mRNA and protein levels are downregulated in human gastric cancer tissues when compared with normal gastric mucosa. Low expression of TET2 predicts poor overall and disease‐free survival. Furthermore, we demonstrate that TET2 inhibits the proliferation and colony formation of human gastric cancer cells by using loss‐of‐function and gain‐of‐function strategies. Overexpression of TET2 induces apoptosis in human gastric cancer cells. The mechanism study shows that TET2 binds to the promoter region of the oncogenic long noncoding RNA (lncRNA‐ANRIL) and regulates the expression of ANRIL and its downstream genes (INK4a, INK4b, and ARF). Finally, we demonstrate that ANRIL knockdown blocks the effects of TET2 on gastric cancer cell proliferation and colony formation. © 2016 IUBMB Life 68(5):355–364, 2016
Induction Chemotherapy for p16 Positive Oropharyngeal Squamous Cell Carcinoma
Authors: Saito Yuki , Ando Mizuo , Omura Go , Yasuhara Kazuo , Yoshida Masafumi , Takahashi Wataru , Yamasoba Tatsuya
Published: March 2016

Objectives/Hypothesis

We aimed to determine the effectiveness of induction chemotherapy for treating p16‐positive oropharyngeal cancer in our department.

Study Design

This was a retrospective case series to assess treatment effectiveness.

Methods

We administered induction chemotherapy to patients with stage III to IV oropharyngeal p16‐positive squamous cell carcinoma between 2008 and 2013. Induction chemotherapy was administered using combinations of docetaxel, cisplatin, and 5‐fluorouracil. We measured the survival rates using the Kaplan‐Meier method and log‐rank test.

Results

We reviewed 23 patients (18 men and 5 women; age, 42–79 years). Induction chemotherapy resulted in partial or complete remission (20 patients) and in stable (2 patients) or progressive (1 patient) disease. In partial or complete remission, subsequent radiotherapy was performed in 16 patients, chemoradiotherapy in two, and transoral resection in two. In stable or progressive disease, subsequent open surgery was performed. Overall, one patient died of cervical lymph node metastasis, one died of kidney cancer, and one died of myocardial infarction. Event‐free, distant‐metastasis–free survival was present for 20 patients. The 3‐year disease‐specific survival was 95%; the overall survival was 87%. Two patients required gastrostomies during chemoradiotherapy and three required tracheotomies, but these were closed in all patients.

Conclusion

The therapeutic response to induction chemotherapy for p16‐positive oropharyngeal cancer was good. Partial or complete remission was achieved in almost 90% patients, and control of local and distant metastases was possible when it was followed by radiotherapy alone or with transoral resection of the primary tumor. A multicenter study is required to confirm these findings.

Level of Evidence

4.
Bazedoxifene and Conjugated Equine Estrogen: A Combination Product for the Management of Vasomotor Symptoms and Osteoporosis Prevention Associated with Menopause
Authors: Umland Elena M. , Karel Lauren , Santoro Nanette
Published: March 2016

Bazedoxifene (BZA), a third‐generation selective estrogen receptor modulator (SERM), has been combined with conjugated equine estrogen (CE) to create a tissue selective estrogen complex (TSEC) for the management of vasomotor symptoms (VMS) and the prevention of osteoporosis (OP) associated with menopause. Both of these outcomes of menopause contribute to significant negative effects on quality of life and increases in utilization of health care resources and dollars. Current treatment modalities for VMS and OP include estrogen therapy that requires the use of progestin in women who have a uterus to reduce the risk of endometrial hyperplasia and resultant cancer. However, progestin use results in nuisance bleeding as well as a further increased risk of breast cancer when combined with estrogen. And while SERMs can be used to prevent OP, their use alone has been shown to increase hot flashes. The combination of BZA and CE does not require progestin treatment with CE as the BZA component acts as an antagonist on endometrial tissue. The U.S. Food and Drug Administration approval of BZA/CE in 2013 was based on a series of five phase 3 studies known as the Selective estrogens, Menopause And Response to Therapy (SMART) trials. These trials, in their entirety, evaluated the impact of BZA/CE on VMS frequency and severity, bone mineral density, bone turnover markers, vaginal symptoms, lipid profiles, sleep, quality of life, breast density, and endometrial safety. The approved dose of BZA/CE is 20 mg BZA and 0.45 mg CE. Although this TSEC manages VMS while opposing breast and endometrial proliferation, preventing bone resorption, and improving lipid profiles, long‐term experience with BZA/CE is currently lacking.
The influence of zirconia precursor/binding polymer mass ratio in the intermediate electrospun composite fibers on the phase transformation of final zirconia nanofibers
Authors: Rodaev Vyacheslav V. , Zhigachev Andrey O. , Korenkov Viktor V. , Golovin Yuri I.
Published: March 2016

Nanofibrous zirconia was fabricated by calcination of electrospun zirconium oxychloride/polyethylene oxide (PEO) composite fibers with different mass fraction of the components. ZrO2 nanofibers were characterized by scanning electron microscopy (SEM), nitrogen adsorption at 77 K, and X‐ray diffractometry (XRD). It was revealed that increase in ZrOCl2/PEO mass ratio above the threshold value significantly decreases tetragonal phase (t‐ZrO2) content and increases monoclinic phase (m‐ZrO2) content in final ceramic nanofibers. Distinct t‐ZrO2 → m‐ZrO2 transformation takes place when average ZrO2 grain size approaches to 30 nm.
It's Time for the Genetic Counseling Profession to Embrace Social Media
Authors: Gallagher Lauren , McCuaig Jeanna , Benoit Lacey , Davies Christine
Published: March 2016

Social Media is a powerful and emerging method of communication that is becoming increasingly popular in genetic counseling and other health care communities. Despite its multiple benefits, the Social Media revolution has been met with some resistance in the healthcare setting. Herein, we will describe the potential benefits of Social Media for the genetic counseling profession specifically and explore ways in which any risks can be mitigated and barriers overcome to ensure responsible Social Media use by the profession.
Spatial patterns of soil and ecosystem respiration regulated by biological and environmental variables along a precipitation gradient in semi‐arid grasslands in China
Authors: Xu Wenfang , Li Xianglan , Liu Wei , Li Linghao , Hou Longyu , Shi Huiqiu , Xia Jiangzhou , Liu Dan , Zhang Haicheng , Chen Yang , Cai Wenwen , Fu Yang , Yuan Wenping
Published: March 2016

Precipitation is a key environmental factor in determining ecosystem structure and function. Knowledge of how soil and ecosystem respiration responds to climate change (e.g., precipitation) and human activities (e.g., grazing or clipping) is crucial for assessing the impacts of climate change on terrestrial ecosystems and for improving model simulations and predictions of future global carbon (C) cycling in response to human activities. In this study, we examined the spatial patterns of soil and ecosystem respiration along a precipitation gradient from 167.7 to 398.1 mm in a semi‐arid grassland. Our results showed that soil and ecosystem respiration increased linearly with increasing mean annual precipitation. The trends were similar to those of shoot biomass, litter and soil total C content along the precipitation gradient. Our results indicated that precipitation was the primary controlling factor in determining the spatial pattern of soil and ecosystem respiration in semi‐arid grasslands in China. The linear/nonlinear relationships in this study describing the variations of the ecosystem carbon process with precipitation can be useful for model development, parameterization and validation at the regional scale to improve predictions of how carbon processes in grasslands respond to climate change, land use and grassland management.
Phenomenal Intentionality and the Problem of Representation
Authors: OTT WALTER
Published: March 2016

According to the phenomenal intentionality research program, a state's intentional content is fixed by its phenomenal character. Defenders of this view have little to say about just how this grounding is accomplished. I argue that without a robust account of representation, the research program promises too little. Unfortunately, most of the well-developed accounts of representation—asymmetric dependence, teleosemantics, and the like—ground representation in external relations such as causation. Such accounts are inconsistent with the core of the phenomenal intentionality program. I argue that, however counterintuitive it may seem, the best prospect for explaining how phenomenal character represents is an appeal to resemblance.
Non-equilibrium dynamics of dense gas under tight confinement
Authors: Wu Lei , Liu Haihu , Reese Jason M. , Zhang Yonghao
Published: March 2016

The force-driven Poiseuille flow of dense gases between two parallel plates is investigated through the numerical solution of the generalized Enskog equation for two-dimensional hard discs. We focus on the competing effects of the mean free path ${\it\lambda}$, the channel width $L$ and the disc diameter ${\it\sigma}$. For elastic collisions between hard discs, the normalized mass flow rate in the hydrodynamic limit increases with $L/{\it\sigma}$ for a fixed Knudsen number (defined as $Kn={\it\lambda}/L$), but is always smaller than that predicted by the Boltzmann equation. Also, for a fixed $L/{\it\sigma}$, the mass flow rate in the hydrodynamic flow regime is not a monotonically decreasing function of $Kn$ but has a maximum when the solid fraction is approximately 0.3. Under ultra-tight confinement, the famous Knudsen minimum disappears, and the mass flow rate increases with $Kn$, and is larger than that predicted by the Boltzmann equation in the free-molecular flow regime; for a fixed $Kn$, the smaller $L/{\it\sigma}$ is, the larger the mass flow rate. In the transitional flow regime, however, the variation of the mass flow rate with $L/{\it\sigma}$ is not monotonic for a fixed $Kn$: the minimum mass flow rate occurs at $L/{\it\sigma}\approx 2{-}3$. For inelastic collisions, the energy dissipation between the hard discs always enhances the mass flow rate. Anomalous slip velocity is also found, which decreases with increasing Knudsen number. The mechanism for these exotic behaviours is analysed.
On the Acceleration of the Multi-Level Monte Carlo Method
Authors: Debrabant Kristian , Röβler Andreas
Published: March 2016

The multi-level Monte Carlo method proposed by Giles (2008) approximates the expectation of some functionals applied to a stochastic process with optimal order of convergence for the mean-square error. In this paper a modified multi-level Monte Carlo estimator is proposed with significantly reduced computational costs. As the main result, it is proved that the modified estimator reduces the computational costs asymptotically by a factor (p / α)2 if weak approximation methods of orders α and p are applied in the case of computational costs growing with the same order as the variances decay.
On the Behaviour of the Backward Interpretation of Feynman-Kac Formulae Under Verifiable Conditions
Authors: Jasra Ajay
Published: March 2016

We consider the time behaviour associated to the sequential Monte Carlo estimate of the backward interpretation of Feynman-Kac formulae. This is particularly of interest in the context of performing smoothing for hidden Markov models. We prove a central limit theorem under weaker assumptions than adopted in the literature. We then show that the associated asymptotic variance expression for additive functionals grows at most linearly in time under hypotheses that are weaker than those currently existing in the literature. The assumptions are verified for some hidden Markov models.
Asymptotic Properties of a Random Graph with Duplications
Authors: Backhausz Ágnes , Móri Tamás F.
Published: March 2016

We deal with a random graph model evolving in discrete time steps by duplicating and deleting the edges of randomly chosen vertices. We prove the existence of an almost surely asymptotic degree distribution, with stretched exponential decay; more precisely, the proportion of vertices of degreedtends to some positive numbercd> 0 almost surely as the number of steps goes to ∞, andcd~ (eπ)1/2d1/4e-2√dholds asd→ ∞.
Quantitative Convergence Rates for Subgeometric Markov Chains
Authors: Andrieu Christophe , Fort Gersende , Vihola Matti
Published: March 2016

We provide explicit expressions for the constants involved in the characterisation of ergodicity of subgeometric Markov chains. The constants are determined in terms of those appearing in the assumed drift and one-step minorisation conditions. The results are fundamental for the study of some algorithms where uniform bounds for these constants are needed for a family of Markov kernels. Our results accommodate also some classes of inhomogeneous chains.
New Results on a Generalized Coupon Collector Problem Using Markov Chains
Authors: Anceaume Emmanuelle , Busnel Yann , Sericola Bruno
Published: March 2016

In this paper we study a generalized coupon collector problem, which consists of determining the distribution and the moments of the time needed to collect a given number of distinct coupons that are drawn from a set of coupons with an arbitrary probability distribution. We suppose that a special coupon called the null coupon can be drawn but never belongs to any collection. In this context, we obtain expressions for the distribution and the moments of this time. We also prove that the almost-uniform distribution, for which all the nonnull coupons have the same drawing probability, is the distribution which minimizes the expected time to obtain a fixed subset of distinct coupons. This optimization result is extended to the complementary distribution of the time needed to obtain the full collection, proving by the way this well-known conjecture. Finally, we propose a new conjecture which expresses the fact that the almost-uniform distribution should minimize the complementary distribution of the time needed to obtain any fixed number of distinct coupons.
The Coalescent in Peripatric Metapopulations
Authors: Lambert Amaury , Ma Chunhua
Published: March 2016

We consider a dynamic metapopulation involving one large population of sizeNsurrounded by colonies of size εNN, usually called peripheral isolates in ecology, whereN→ ∞ and εN→ 0 in such a way that εNN→ ∞. The main population, as well as the colonies, independently send propagules to found new colonies (emigration), and each colony independently, eventually merges with the main population (fusion). Our aim is to study the genealogical history of a finite number of lineages sampled at stationarity in such a metapopulation. We make assumptions on model parameters ensuring that the total outer population has size of the order ofNand that each colony has a lifetime of the same order. We prove that under these assumptions, the scaling limit of the genealogical process of a finite sample is a censored coalescent where each lineage can be in one of two states: an inner lineage (belonging to the main population) or an outer lineage (belonging to some peripheral isolate). Lineages change state at constant rate and (only) inner lineages coalesce at constant rate per pair. This two-state censored coalescent is also shown to converge weakly, as the landscape dynamics accelerate, to a time-changed Kingman coalescent.
Approximations: replacing random variables with their means
Authors: Gani Joe
Published: March 2016

One of the standard methods for approximating a bivariate continuous-time Markov chain {X(t), Y(t): t ≥ 0}, which proves too difficult to solve in its original form, is to replace one of its variables by its mean, This leads to a simplified stochastic process for the remaining variable which can usually be solved, although the technique is not always optimal. In this note we consider two cases where the method is successful for carrier infections and mutating bacteria, and one case where it is somewhat less so for the SIS epidemics.
The naming game in language dynamics revisited
Authors: Lanchier Nicolas
Published: March 2016

In this article we study a biased version of the naming game in which players are located on a connected graph and interact through successive conversations in order to select a common name for a given object. Initially, all the players use the same word B except for one bilingual individual who also uses word A. Both words are attributed a fitness, which measures how often players speak depending on the words they use and how often each word is spoken by bilingual individuals. The limiting behavior depends on a single parameter, ϕ, denoting the ratio of the fitness of word A to the fitness of word B. The main objective is to determine whether word A can invade the system and become the new linguistic convention. From the point of view of the mean-field approximation, invasion of word A is successful if and only if ϕ > 3, a result that we also prove for the process on complete graphs relying on the optimal stopping theorem for supermartingales and random walk estimates. In contrast, for the process on the one-dimensional lattice, word A can invade the system whenever ϕ > 1.053, indicating that the probability of invasion and the critical value for ϕ strongly depend on the degree of the graph. The system on regular lattices in higher dimensions is also studied by comparing the process with percolation models.
Stackelberg equilibria in a continuous-time vertical contracting model with uncertain demand and delayed information
Authors: Øksendal Bernt , Sandal Leif , Ubøe Jan
Published: March 2016

We consider explicit formulae for equilibrium prices in a continuous-time vertical contracting model. A manufacturer sells goods to a retailer, and the objective of both parties is to maximize expected profits. Demand is an Itô-Lévy process, and to increase realism, information is delayed. We provide complete existence and uniqueness proofs for a series of special cases, including geometric Brownian motion and the Ornstein-Uhlenbeck process, both with time-variable coefficients. Moreover, explicit solution formulae are given, so these results are operational. An interesting finding is that information that is more precise may be a considerable disadvantage for the retailer.
Two-node fluid network with a heavy-tailed random input: the strong stability case
Authors: Foss Sergey , Miyazawa Masakiyo
Published: March 2016

We consider a two-node fluid network with batch arrivals of random size having a heavy-tailed distribution. We are interested in the tail asymptotics for the stationary distribution of a two-dimensional workload process. Tail asymptotics have been well studied for two-dimensional reflecting processes where jumps have either a bounded or an unbounded light-tailed distribution. However, the presence of heavy tails totally changes these asymptotics. Here we focus on the case of strong stability where both nodes release fluid at sufficiently high speeds to minimise their mutual influence. We show that, as in the one-dimensional case, big jumps provide the main cause for workloads to become large, but now they can have multidimensional features. We first find the weak tail asymptotics of an arbitrary directional marginal of the stationary distribution at Poisson arrival epochs. In this analysis, decomposition formulae for the stationary distribution play a key role. Then we employ sample-path arguments to find the exact tail asymptotics of a directional marginal at renewal arrival epochs assuming one-dimensional batch arrivals.
Return to the Poissonian city
Authors: Kendall Wilfrid S.
Published: March 2016

Consider the following random spatial network: in a large disk, construct a network using a stationary and isotropic Poisson line process of unit intensity. Connect pairs of points using the network, with initial/final segments of the connecting path formed by travelling off the network in the opposite direction to that of the destination/source. Suppose further that connections are established using ‘near geodesics’, constructed between pairs of points using the perimeter of the cell containing these two points and formed using only the Poisson lines not separating them. If each pair of points generates an infinitesimal amount of traffic divided equally between the two connecting near geodesics, and if the Poisson line pattern is conditioned to contain a line through the centre, then what can be said about the total flow through the centre? In Kendall (2011) it was shown that a scaled version of this flow has asymptotic distribution given by the 4-volume of a region in 4-space, constructed using an improper anisotropic Poisson line process in an infinite planar strip. Here we construct a more amenable representation in terms of two ‘seminal curves’ defined by the improper Poisson line process, and establish results which produce a framework for effective simulation from this distribution up to anL1error which tends to 0 with increasing computational effort.
Exact boundaries in sequential testing for phase-type distributions
Authors: Albrecher Hansjörg , Asadi Peiman , Ivanovs Jevgenijs
Published: March 2016

Consider Wald's sequential probability ratio test for deciding whether a sequence of independent and identically distributed observations comes from a specified phase-type distribution or from an exponentially tilted alternative distribution. Exact decision boundaries for given type-I and type-II errors are derived by establishing a link with ruin theory. Information on the mean sample size of the test can be retrieved as well. The approach relies on the use of matrix-valued scale functions associated with a certain one-sided Markov additive process. By suitable transformations, the results also apply to other types of distributions, including some distributions with regularly varying tails.
The extended hypergeometric class of Lévy processes
Authors: Kyprianou A. E. , Pardo J. C. , Watson A. R.
Published: March 2016

We review and extend the class of hypergeometric Lévy processes explored in Kuznetsov and Pardo (2013) with a view to computing fluctuation identities related to stable processes. We give the Wiener-Hopf factorisation of a process in the extended class, characterise its exponential functional, and give three concrete examples arising from transformations of stable processes.
Optimal control policy for a Brownian inventory system with concave ordering cost
Authors: Yao Dacheng , Chao Xiuli , Wu Jingchen
Published: March 2016

In this paper we consider an inventory system with increasing concave ordering cost and average cost optimization criterion. The demand process is modeled as a Brownian motion. Porteus (1971) studied a discrete-time version of this problem and under the strong condition that the demand distribution belongs to the class of densities that are finite convolutions of uniform and/or exponential densities (note that normal density does not belong to this class), an optimal control policy is a generalized (s, S) policy consisting of a sequence of (si
, Si
). Using a lower bound approach, we show that an optimal control policy for the Brownian inventory model is determined by a single pair (s, S).
Randomisation and recursion methods for mixed-exponential Lévy models, with financial applications
Authors: Mijatović Aleksandar , Pistorius Martijn R. , Stolte Johannes
Published: March 2016

We develop a new Monte Carlo variance reduction method to estimate the expectation of two commonly encountered path-dependent functionals: first-passage times and occupation times of sets. The method is based on a recursive approximation of the first-passage time probability and expected occupation time of sets of a Lévy bridge process that relies in part on a randomisation of the time parameter. We establish this recursion for general Lévy processes and derive its explicit form for mixed-exponential jump-diffusions, a dense subclass (in the sense of weak approximation) of Lévy processes, which includes Brownian motion with drift, Kou's double-exponential model, and hyperexponential jump-diffusion models. We present a highly accurate numerical realisation and derive error estimates. By way of illustration the method is applied to the valuation of range accruals and barrier options under exponential Lévy models and Bates-type stochastic volatility models with exponential jumps. Compared with standard Monte Carlo methods, we find that the method is significantly more efficient.
Large deviations for multidimensional state-dependent shot-noise processes
Authors: Budhiraja Amarjit , Nyquist Pierre
Published: March 2016

Shot-noise processes are used in applied probability to model a variety of physical systems in, for example, teletraffic theory, insurance and risk theory, and in the engineering sciences. In this paper we prove a large deviation principle for the sample-paths of a general class of multidimensional state-dependent Poisson shot-noise processes. The result covers previously known large deviation results for one-dimensional state-independent shot-noise processes with light tails. We use the weak convergence approach to large deviations, which reduces the proof to establishing the appropriate convergence of certain controlled versions of the original processes together with relevant results on existence and uniqueness.
On degenerate sums of m-dependent variables
Authors: Janson Svante
Published: March 2016

It is well known that the central limit theorem holds for partial sums of a stationary sequence (Xi
) of m-dependent random variables with finite variance; however, the limit may be degenerate with variance 0 even if var(Xi
) ≠ 0. We show that this happens only in the case when Xi
– EXi
= Yi
– Yi

–1 for an (m − 1)-dependent stationary sequence (Yi
) with finite variance (a result implicit in earlier results), and give a version for block factors. This yields a simple criterion that is a sufficient condition for the limit not to be degenerate. Two applications to subtree counts in random trees are given.
Erratum to: Mixture representations of residual lifetimes of used systems
Authors: Kamińska-Zabierowska Maria , Navarro Jorge
Published: March 2016

We have found a mistake in the proofs of Navarro (2008, Theorem 2.3(b) and 2.3(c)) due to misapplication of properties of hazard rate and likelihood ratio orders. In this paper we show with an example that the stated results do not hold. This example is interesting since it proves some unexpected properties for these orderings under the formation of coherent systems. The result stated in Navarro (2008, Theorem 2.3(a)) for the usual stochastic order is correct.
Reversible Markov structures on divisible set partitions
Authors: Crane Harry , McCullagh Peter
Published: March 2016

We studyk-divisible partition structures, which are families of random set partitions whose block sizes are divisible by an integerk= 1, 2, …. In this setting, exchangeability corresponds to the usual invariance under relabeling by arbitrary permutations; however, fork> 1, the ordinary deletion maps on partitions no longer preserve divisibility, and so a random deletion procedure is needed to obtain a partition structure. We describe explicit Chinese restaurant-type seating rules for generating families of exchangeablek-divisible partitions that are consistent under random deletion. We further introduce the notion ofMarkovian partition structures, which are ensembles of exchangeable Markov chains onk-divisible partitions that are consistent under a random process ofMarkovian deletion. The Markov chains we study are reversible and refine the class of Markov chains introduced in Crane (2011).
The Kalman-Bucy filter for integrable Lévy processes with infinite second moment
Authors: Applebaum David , Blackwood Stefan
Published: March 2016

We extend the Kalman-Bucy filter to the case where both the system and observation processes are driven by finite dimensional Lévy processes, but whereas the process driving the system dynamics is square-integrable, that driving the observations is not; however it remains integrable. The main result is that the components of the observation noise that have infinite variance make no contribution to the filtering equations. The key technique used is approximation by processes having bounded jumps.
The moments of the discounted loss and the discounted dividends for a spectrally negative Lévy risk process
Authors: Frostig Esther
Published: March 2016

Consider a spectrally negative risk process where, on ruin, the deficit is immediately paid, and the process restarts from 0. When the process reaches a threshold b, all the surplus above b is paid as dividend. Applying the theory of exit times for a spectrally negative Lévy process and its reflection at the maximum and at the minimum, we obtain recursive formulae for the following moments. (i) The moments of the discounted loss until the process reaches b. This is equivalent to the moments of the discounted dividends in the dual model under the barrier strategy. (ii) The moments of the discounted loss for models with and without a dividend barrier for the infinite horizon. (iii) The moments of the discounted dividends for the infinite horizon.