bluuebunny/crossref_metadata_2025_split huggingface dataset:
Organic carbon preservation in Southeastern Arabian Sea sediments since mid‐Holocene: Implications to South Asian Summer Monsoon variability
Authors: Nagoji Siddhesh S. , Tiwari Manish 
Published: August 2017

AbstractThe earlier studies show a contrasting long‐term trend of the South Asian Summer Monsoon (SASM) after attaining the precessional forcing induced mid‐Holocene maximum. The increasing total organic carbon (TOC) concentration of marine sediments in the Southeastern Arabian Sea (SEAS) has been interpreted to imply strengthening SASM since mid‐Holocene by a few studies. However, TOC concentration is also influenced by redox conditions, sedimentation rate, and an influx of terrigenous matter depending on the regional settings. So, it needs to be ascertained whether the TOC concentration of the sediments in the SEAS is a signal of productivity related to the SASM strength or preservation. Therefore, we studied multiple proxies (TOC, total nitrogen, atomic C/N, δ13Corg, CaCO3, and major and trace elements concentration) for determining the productivity, redox conditions, detrital supply, and provenance in a sediment core from the upper continental slope of the SEAS spanning the past ∼4700 years at centennial scale resolution. The present study shows that the observed increase in the TOC values since the mid‐Holocene is a result of better preservation caused by increased sedimentation rate and enhanced reducing conditions. We further show that the SASM has been declining since mid‐Holocene after attaining a precession‐forced maximum, which corroborates the earlier model ensemble studies.
Tracking precipitation events in time and space in gridded observational data
Authors: White R. H. , Battisti D. S. , Skok G. 
Published: August 2017

AbstractNovel precipitation event data sets are created by tracking 3‐hourly observed rainfall in both time and space in the TRMM 3B42 and ERA‐Interim data sets. Relative to TRMM, ERA‐Interim data undersimulate the total number of events (factor of ∼0.5), and oversimulate the frequency of events lasting >5 days (factor of 1.6). Longer‐lasting events tend to have larger spatial footprints and higher intensity precipitation at any point in their lifetime, and thus contribute significantly more to total precipitation than shorter events. Precipitation changes in selected tropical and subtropical regions are attributed to different event characteristics: some to changes in event rainfall intensity, others to changes in the number of events. In the 40°S–40°N spatial average, the number of events lasting 1–5 days significantly increased from 1998 to 2014 in both the TRMM 3B42 and ERA‐Interim data. The event data sets, analysis scripts, and selected processed data are freely available online.
On production of gamma rays and relativistic runaway electron avalanches from Martian dust storms
Authors: Arabshahi Shahab , Majid Walid A. , Dwyer Joseph R. , Rassoul Hamid K. 
Published: August 2017

AbstractProduction of runaway electron avalanches and gamma rays originating inside Martian dust storms are studied using Monte Carlo simulations. In the absence of in situ measurements, we use theoretical predictions of electric fields inside dust storms. Electrons are produced through the relativistic runaway electron avalanches process, and energetic photons are results of the bremsstrahlung scattering of the electrons with the air. Characteristic lengths of the runaway electron avalanche for different electric fields and the energy spectrum of electrons are derived and compared to their terrestrial counterparts. It is found that it is possible for Martian dust storms to develop energetic electron avalanches and produce large fluxes of gamma ray photons similar to terrestrial gamma ray flashes from Earth's thunderstorms. The phenomenon could be called Martian gamma ray flash, and due to the very thin atmosphere on Mars, it can be observed by both ground‐based instruments or satellites orbiting the planet.
Considerable contribution of the Montreal Protocol to declining greenhouse gas emissions from the United States
Authors: Hu Lei , Montzka Stephen A. , Lehman Scott J. , Godwin David S. , Miller Benjamin R. , Andrews Arlyn E. , Thoning Kirk , Miller John B. , Sweeney Colm , Siso Caroline , Elkins James W. , Hall Bradley D. , Mondeel Debra J. , Nance David , Nehrkorn Thomas , Mountain Marikate , Fischer Marc L. , Biraud Sébastien C. , Chen Huilin , Tans Pieter P. 
Published: August 2017

AbstractOzone depleting substances (ODSs) controlled by the Montreal Protocol are potent greenhouse gases (GHGs), as are their substitutes, the hydrofluorocarbons (HFCs). Here we provide for the first time a comprehensive estimate of U.S. emissions of ODSs and HFCs based on precise measurements in discrete air samples from across North America and in the remote atmosphere. Derived emissions show spatial and seasonal variations qualitatively consistent with known uses and largely confirm U.S. Environmental Protection Agency (EPA) national emissions inventories for most gases. The measurement‐based results further indicate a substantial decline of ODS emissions from 2008 to 2014, equivalent to ~50% of the CO2‐equivalent decline in combined emissions of CO2 and all other long‐lived GHGs inventoried by the EPA for the same period. Total estimated CO2‐equivalent emissions of HFCs were comparable to the sum of ODS emissions in 2014, but can be expected to decline in the future in response to recent policy measures.
A reduction in the asymmetry of ENSO amplitude due to global warming: The role of atmospheric feedback
Authors: Ham Yoo‐Geun 
Published: August 2017

AbstractThis study analyzes a reduction in the asymmetry of El Niño Southern–Oscillation (ENSO) amplitude due to global warming in Coupled Model Intercomparison Project Phase 5 models. The multimodel‐averaged Niño3 skewness during December–February season decreased approximately 40% in the RCP4.5 scenario compared to that in the historical simulation. The change in the nonlinear relationship between sea surface temperature (SST) and precipitation is a key factor for understanding the reduction in ENSO asymmetry due to global warming. In the historical simulations, the background SST leading to the greatest precipitation sensitivity (SST for Maximum Precipitation Sensitivity, SST_MPS) occurs when the positive SST anomaly is located over the equatorial central Pacific. Therefore, an increase in climatological SST due to global warming weakens the atmospheric response during El Niño over the central Pacific. However, the climatological SST over this region in the historical simulation is still lower than the SST_MPS for the negative SST anomaly; therefore, a background SST increase due to global warming can further increase precipitation sensitivity. The atmospheric feedbacks during La Niña are enhanced and increase the La Niña amplitude due to global warming.
The spatial extent of rainfall events and its relation to precipitation scaling
Authors: Lochbihler Kai , Lenderink Geert , Siebesma A. Pier 
Published: August 2017

AbstractObservations show that subdaily precipitation extremes increase with dew point temperature at a rate exceeding the Clausius‐Clapeyron (CC) relation. The understanding of this so‐called super CC scaling is still incomplete, and observations of convective cell properties could provide important information. Here the size and intensity of rain cells are investigated by using a tracking of rainfall events in high‐resolution radar data. Higher intensities are accompanied by larger rainfall areas. However, whereas small rain cells mainly follow CC scaling, larger cells display super CC behavior. Even more, for dew point exceeding 15°C, the rain cell size has to increase in order to sustain super CC scaling and a remarked increase in rain cell area is found. Our results imply that the source area of moisture, the cloud size, and the degree of mesoscale organization play key roles in the context of a warming climate.
On the diurnal cycle of surface energy fluxes in the North American monsoon region using the WRF‐Hydro modeling system
Authors: Xiang Tiantian , Vivoni Enrique R. , Gochis David J. , Mascaro Giuseppe 
Published: August 2017

AbstractThe diurnal cycles of surface energy fluxes are important drivers of atmospheric boundary layer development and convective precipitation, particularly in regions with heterogeneous land surface conditions such as those under the influence of the North American monsoon (NAM). Characterization of diurnal surface fluxes and their controls has not been well constrained due to the paucity of observations in the NAM region. In this study, we evaluate the performance of the uncoupled WRF‐Hydro modeling system in its ability to represent soil moisture, turbulent heat fluxes, and surface temperature observations and compare these to operational analyses from other commonly used land surface models (LSMs). After a rigorous model evaluation, we quantify how the diurnal cycles of surface energy fluxes vary during the warm season for the major ecosystems in a regional basin. We find that the diurnal cycle of latent heat flux is more sensitive to ecosystem type than sensible heat flux due to the response of plant transpiration to variations in soil water content. Furthermore, the peak timing of precipitation affects the shape and magnitude of the diurnal cycle of plant transpiration in water‐stressed ecosystems, inducing mesoscale heterogeneity in land surface conditions between the major ecosystems within the basin. Comparisons to other LSMs indicate that ecosystem differences in the diurnal cycle of turbulent fluxes are underestimated in these products. While this study shows how land surface heterogeneity affects the simulated diurnal cycle of turbulent fluxes, additional coupled modeling efforts are needed to identify the potential impacts of these spatial differences on convective precipitation.
Impact of ocean warming on tropical cyclone track over the western north pacific: A numerical investigation based on two case studies
Authors: Sun Yuan , Zhong Zhong , Li Tim , Yi Lan , Camargo Suzana J. , Hu Yijia , Liu Kefeng , Chen Haishan , Liao Qianfeng , Shi Jian 
Published: August 2017

AbstractThe impact of ocean warming on tropical cyclone (TC) track over the western North Pacific is an open issue. Relatively little is known about possible changes in TC tracks under ocean warming conditions due to both inhomogeneous observation networks and large natural variability over a relatively short observational period. A suite of semiidealized numerical experiments on two TC cases is conducted to investigate the response of TC tracks to increases in sea surface temperature (SST). It is found that the simulated TC track is highly sensitive to underlying SST. Specifically, through its influence on the radial distribution of sea surface enthalpy, ocean warming can lead to changes in the tangential wind profile and thus increase the TC size in terms of the radius of gale force wind, which is attributed to the increase in maximum wind speed, the expansion of the radius of maximum wind, and the additional increase in outer winds. The increased TC size, as suggested by previous studies, further leads to the eastward withdrawal of the western Pacific subtropical high (WPSH) and thus a northward turning of the TC. Results of climate simulations in the present study provide further evidence for the aforementioned impact of ocean warming on TC size and thus the WPSH and TC track. Results of the present study also imply that the threat of storms to countries in East Asia may be reduced due to possible changes in TC tracks if ocean warming continues in the future.
Impacts of northern Tibetan Plateau on East Asian summer rainfall via modulating midlatitude transient eddies
Authors: Deng Jiechun , Xu Haiming , Shi Ning , Zhang Leying , Ma Jing 
Published: August 2017

AbstractRoles of the Tibetan Plateau (TP) in forming and changing the seasonal Asian climate system have been widely explored. However, little is known about modulation effects of the TP on extratropical transient eddies (TEs) and subsequent synoptic responses of the East Asian rainfall. In this study, the Community Atmosphere Model version 5.1 coupled with a slab ocean model is employed to highlight the important role of the TP in regulating the upper‐tropospheric transient wave train. Comparison between sensitivity experiments with and without the TP shows that the northern TP excites a strong anomalous anticyclone, which shifts the upper‐level East Asian westerly jet northward and helps transfer barotropic and baroclinic energy from the mean flow to the synoptic TE flow. The transient wave train is primarily shifted northward by northern TP and is forced to propagate southeastward along the eastern flank of the TP until reaching eastern China. Before the strengthening of monsoonal southerlies, the TP‐modulated transient wave train cools the troposphere, which decreases the static stability over northern China. Meanwhile, the associated anomalous warm advection induces ascending motion, leading to excessive rainfall by releasing unstable energy as the southerly strengthens. Due to the southeastward propagation of the wave train, anomalous heavy rainfall subsequently appears over eastern China from north to south, which increases day‐to‐day rainfall variation in this region. Additionally, occurrence of this upper‐tropospheric transient wave train associated with low‐level southerly peak is substantially increased by northern TP.
Reassessing the role of temperature in precipitation oxygen isotopes across the eastern and central United States through weekly precipitation‐day data
Authors: Akers Pete D. , Welker Jeffrey M. , Brook George A. 
Published: August 2017

AbstractAir temperature is correlated with precipitation oxygen isotope (δ18Oprcp) variability for much of the eastern and central United States, but the nature of this δ18Oprcp‐temperature relationship is largely based on data coarsely aggregated at a monthly resolution. We constructed a database of 6177 weeks of isotope and precipitation‐day air temperature data from 25 sites to determine how more precise data change our understanding of this classic relationship. Because the δ18Oprcp‐temperature relationship is not perfectly linear, trends in the regression residuals suggest the influence of additional environmental factors such as moisture recycling and extratropical cyclone interactions. Additionally, the temporal relationships between δ18Oprcp and temperature observed in the weekly data at individual sites can explain broader spatial patterns observed across the study region. For 20 of 25 sites, the δ18Oprcp‐temperature relationship slope is higher for colder precipitation than for warmer precipitation. Accordingly, northern and western sites with relatively more cold precipitation events have steeper overall relationships with higher slope values than southeastern sites that have more warm precipitation events. Although the magnitude of δ18Oprcp variability increases to the north and west, the fraction of δ18Oprcp variability explained by temperature increases due to wider annual temperature ranges, producing stronger relationships in these regions. When our δ18Oprcp‐temperature data are grouped by month, we observe significant variations in the relationship from month to month. This argues against a principal causative role for temperature and suggests the existence of an alternative environmental control on δ18Oprcp values that simply covaries seasonally with temperature.
Coordinating water conservation efforts through tradable credits: A proof of concept for drought response in the San Francisco Bay area
Authors: Gonzales Patricia , Ajami Newsha , Sun Yujie 
Published: August 2017

AbstractWater utilities are increasingly relying on water efficiency and conservation to extend the availability of supplies. Despite spatial and institutional interdependency of many utilities, these demand‐side management initiatives have traditionally been tackled by individual utilities operating in isolation. In this study, we introduce a policy framework for water conservation credits that enables collaboration at the regional scale. Under the proposed approach, utilities have the flexibility to invest in water conservation measures that are appropriate for their specific service area. When utilities have insufficient capacity for local cost‐effective measures, they may opt to purchase credits, contributing to fund subsidies for utilities that do have that capacity and can provide the credits, while the region as a whole benefits from more reliable water supplies. This work aims to provide insights on the potential impacts of a water conservation credit policy framework when utilities are given the option to collaborate in their efforts. We model utility decisions as rational cost‐minimizing actors subject to different decision‐making dynamics and water demand scenarios, and demonstrate the institutional characteristics needed for the proposed policy to be effective. We apply this model to a counterfactual case study of water utility members of the Bay Area Water Supply and Conservation Agency in California during the drought period of June 2015 to May 2016. Our scenario analysis indicates that when the institutional structure and incentives are appropriately defined, water agencies can achieve economic benefits from collaborating in their conservation efforts, especially if they coordinate more closely in their decision‐making.
Base flow recession from unsaturated‐saturated porous media considering lateral unsaturated discharge and aquifer compressibility
Authors: Liang Xiuyu , Zhan Hongbin , Zhang You‐Kuan , Schilling Keith 
Published: August 2017

AbstractUnsaturated flow is an important process in base flow recessions and its effect is rarely investigated. A mathematical model for a coupled unsaturated‐saturated flow in a horizontally unconfined aquifer with time‐dependent infiltrations is presented. The effects of the lateral discharge of the unsaturated zone and aquifer compressibility are specifically taken into consideration. Semianalytical solutions for hydraulic heads and discharges are derived using Laplace transform and Cosine transform. The solutions are compared with solutions of the linearized Boussinesq equation (LB solution) and the linearized Laplace equation (LL solution), respectively. A larger dimensionless constitutive exponent
(a smaller retention capacity) of the unsaturated zone leads to a smaller discharge during the infiltration period and a larger discharge after the infiltration. The lateral discharge of the unsaturated zone is significant when
, and becomes negligible when
100. The compressibility of the aquifer has a nonnegligible impact on the discharge at early times. For late times, the power index
of the recession curve
∼
, is 1 and independent of
, where Q is the base flow and a is a constant lumped aquifer parameter. For early times,
is approximately equal to 3 but it approaches infinity when
. The present solution is applied to synthetic and field cases. The present solution matched the synthetic data better than both the LL and LB solutions, with a minimum relative error of 16% for estimate of hydraulic conductivity. The present solution was applied to the observed streamflow discharge in Iowa, and the estimated values of the aquifer parameters were reasonable.
Electroenhanced Antimicrobial Coating Based on Conjugated Polymers with Covalently Coupled Silver Nanoparticles Prevents Staphylococcus aureus Biofilm Formation
Authors: Gomez‐Carretero Salvador , Nybom Rolf , Richter‐Dahlfors Agneta 
Published: August 2017

AbstractThe incidence of hospital‐acquired infections is to a large extent due to device‐associated infections. Bacterial attachment and biofilm formation on surfaces of medical devices often act as seeding points of infection. To prevent such infections, coatings based on silver nanoparticles (AgNPs) are often applied, however with varying clinical success. Here, the traditional AgNP‐based antibacterial technology is reimagined, now forming the base for an electroenhanced antimicrobial coating. To integrate AgNPs in an electrically conducting polymer layer, a simple, yet effective chemical strategy based on poly(hydroxymethyl 3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT‐MeOH:PSS) and (3‐aminopropyl)triethoxysilane is designed. The resultant PEDOT‐MeOH:PSS–AgNP composite presents a consistent coating of covalently linked AgNPs, as shown by scanning electron microscopy and surface plasmon resonance analysis. The efficacy of the coatings, with and without electrical addressing, is then tested against Staphylococcus aureus, a major colonizer of medical implants. Using custom‐designed culturing devices, a nearly complete prevention of biofilm growth is obtained in AgNP composite devices addressed with a square wave voltage input. It is concluded that this electroenhancement of the bactericidal effect of the coupled AgNPs offers a novel, efficient solution against biofilm colonization of medical implants.
Phase II study on early start of chemotherapy after excising primary colorectal cancer with distant metastases (Pearl Star 02)
Authors: Yoshida Yoichiro , Aisu Naoya , Kojima Daibo , Mera Toshiyuki , Kiyomi Fumiaki , Yamashita Yuichi , Hasegawa Suguru 
Published: August 2017

AbstractInitiating chemotherapy usually requires a delay of more than 4 weeks after surgically resecting colorectal cancer. However, there is little evidence regarding the required delay interval. We have previously reported a pilot study to determine the safety and feasibility of early initiation of chemotherapy after resecting primary colorectal cancer with distant metastases. We aimed to determine the safety and efficacy of early initiation of chemotherapy after resecting colorectal cancer with distant metastases.This phase II study (trial number UMIN000006310) was a prospective, single‐arm trial. A total of 20 patients (men, 15 and women, 5) were enrolled. They underwent XELOX therapy (130 mg/m2 oxaliplatin on day 1+1000 mg/m2 capecitabine twice daily on days 1‐4) on postoperative day 7 and XELOX+bevacizumab (7.5 mg/kg bevacizumab on day 1) after the second chemotherapy cycle.Baseline characteristics included a median age of 64 (range, 43‐72) years. Surgical procedures included right hemicolectomy in six patients, sigmoidectomy in three, anterior resection in five, and Hartmann procedure in six. All patients started chemotherapy on postoperative day 7. Median progression‐free survival was 14.9 months; overall response rate was 80%. Disease control rate was 100%. Grade 3 or higher hemotoxicity and grade 3 or higher non‐hematological toxicity was noted in 5.0% and 25.0% of patients, respectively. Postoperative complications were observed in two patients (superficial incisional surgical site infection and ileus).Early initiation of chemotherapy after surgery is feasible. These findings suggest future changes of the start time of chemotherapy after surgery.
Output Tracking for One‐Dimensional Schrödinger Equation subject to Boundary Disturbance
Authors: Liu Jun‐Jun , Wang Jun‐Min , Guo Ya‐Ping 
Published: August 2017

AbstractIn this paper, we are concerned with the output reference signal tracking for a one dimensional Schrödinger equation subject to general harmonic disturbance at one end and the control at the another end. Based on the reference signal, we design a state reference system and the output feedback control to cancel the disturbance and track the output reference signal. We show that the whole closed‐loop system is well‐posed and the performance output is tracking the reference signal. The numerical experiments are carried out to illustrate the approach effective.