bluuebunny/crossref_metadata_2025 huggingface dataset:
Hydraulic-Fracture Design: Optimization Under Uncertainty
Authors: Wilson Adam
Published: February 2016

This article, written by Special Publications Editor Adam Wilson, contains highlights of paper OTC 25179, “Hydraulic-Fracture Design for the Lower Tertiary Gulf of Mexico: Optimization Under Uncertainty,” by S.B. Podhoretz, SPE, and P.P. Valko, SPE, Texas A&M University, prepared for the 2014 Offshore Technology Conference, Houston, 5–8 May. The paper has not been peer reviewed.

Massive hydraulic fracturing is a costly operation, particularly offshore where logistic constraints and high rig rates add significant financial risk. For the Lower Tertiary Gulf of Mexico, limited production from analogous fields and very high appraisal-drilling costs result in huge uncertainty for key reservoir parameters and a lack of consensus on best practices for fracture design. This paper provides new approaches to fracture design for thick, vertically anisotropic reservoirs, when considerable uncertainty in reservoir parameters amplifies the financial risks associated with water depth and remoteness.

Risk Analysis

Offshore applications are subject to significant risk because of hostile operating environments and the extreme costs involved. Although multistage hydraulic fracturing for productivity is common onshore, with financial risks well understood, the same cannot be said for offshore.

Compared with the entire cost of drilling and completing an offshore well, the proppant cost is nearly insignificant. However, the risk associated with fracturing is paramount because any nonproductive time could cost millions of dollars because of high day-rate costs.

For future analysis and forecasting, a Markov chain of completion time with respect to number of stages was generated. The Markov chain represents an independent transition from one state to the next. The transition does not depend on the previous states, only on the current state. Assuming a log-normal distribution, a series of Markov chains is generated to predict nonproductive time associated with fracturing additional stages.

These realizations are used to generate probability-density curves representing the time associated with fracturing more stages. The probability- density plots are given in Fig. 1.

These results can be used in determining the expected value and standard deviation of total (productive plus nonproductive) time associated with fracturing additional stages. Not surprisingly, increasing the number of stages moves the location of the peak to the right, but the spread of the curves grows even faster.
Application of Intelligent-Well Technology to an SAGD Producer: Firebag Field Trial
Authors: Carpenter Chris
Published: February 2016

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 170153, “Application of Intelligent-Well Technology to an SAGD Producer: Firebag Field Trial,” by Richard M. Stahl and Jennifer D. Smith, Suncor Energy; Scott Hobbs, Halliburton; and Colin M. Clarke, Baker Hughes, prepared for the 2014 SPE Heavy Oil Conference—Canada, Calgary, 10–12 June. The paper has not been peer reviewed.

An even temperature conformance along the length of the horizontal well is key in maximizing steam-assisted- gravity-drainage (SAGD) production rates. When temperature logs are run in SAGD producers, temperature variations of greater than 50°C between the hottest and coldest spots are commonly observed. The authors theorize that this temperature distribution is related to an inflow distribution and that production rates could be improved if this temperature variance was narrowed.

Introduction

The Firebag project in northeastern Alberta uses SAGD to recover bitumen from the McMurray formation. SAGD uses stacked horizontal-well pairs, with the top well (injector) located 4 to 6 m above the bottom well (producer). Steam is injected into the top well, warming the bitumen and decreasing its viscosity to a point at which it will flow by gravity to the bottom well. The bottom well typically uses artificial lift to draw fluid into the wellbore and push it up to the surface facilities.

Firebag production wells are designed to promote even temperature conformance to maximize bitumen-production rates. The standard Firebag mechanical-lift design is shown in Fig. 1. Temperature conformance is measured by fiber-optic temperature logging while the production well is shut down for an electrical-submersible-pump (ESP) change.

A temperature survey was performed on a typical well, indicating that the coolest temperature (150°C) is located near the heel of the well (approximately 700 m) with a maximum value of 210°C near the midpoint of the well (approximately 1050 m). Field history at Firebag suggests that well conformance and bitumen-production rates could be improved through well design.
National rural drinking water monitoring: progress and challenges with India's IMIS database
Authors: Wescoat James L. , Fletcher Sarah , Novellino Marianna
Published: February 2016

National drinking water programs seek to address monitoring challenges that include self-reporting, data sampling, data consistency and quality, and sufficient frequency to assess the sustainability of water systems. India stands out for its comprehensive rural water database known as Integrated Management Information System (IMIS), which conducts annual monitoring of drinking water coverage, water quality, and related program components from the habitation level to the district, state, and national levels. The objective of this paper is to evaluate IMIS as a national rural water supply monitoring platform. This is important because IMIS is the official government database for rural water in India, and it is used to allocate resources and track the results of government policies. After putting India's IMIS database in an international context, the paper describes its detailed structure and content. It then illustrates the geographic patterns of water supply and water quality that IMIS can present, as well as data analysis issues that were identified. In particular, the fifth section of the paper identifies limitations on the use of state-level data for explanatory regression analysis. These limitations lead to recommendations for improving data analysis to support national rural water monitoring and evaluation, along with strategic approaches to data quality assurance, data access, and database functionality.
Effects of Fe(III) on biofilm and its extracellular polymeric substances (EPS) in fixed bed biofilm reactors
Authors: Hu Xuewei , Chen Kai , Lai Xinke , Ji Siping , Kaiser Kevin
Published: February 2016

The effects of Fe(III) on the biofilm mass and activity, the biofilm micromorphology as well as the composition and functional groups characteristics of extracellular polymeric substances (EPS) in biofilm were investigated in laboratory-scale fixed bed biofilm reactors. The results showed that 2 mg/L of Fe(III) promoted the biofilm mass and improved the biofilm activity, but 16 mg/L of Fe(III) adversely affected biofilm development. Scanning electron microscopy (SEM) study indicated a high concentration (16 mg/L) of Fe(III) led to signiﬁcant reduction of the ﬁlaments, great promotion of the EPS secretion in biofilm. The result of the EPS composition suggested 2 mg/L of Fe(III) increased soluble EPS and loosely bound EPS which contributed to the microbial aggregation, while 16 mg/L of Fe(III) promoted tightly bound EPS production unfavourable for substrate mass transfer. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analysis demonstrated that Fe(III) exerted a significant influence on the –CONH– groups of proteins and the C–O groups of polysaccharides in EPS. This study reveals that Fe(III) influences biofilm development and activity not only by directly impacting the microbial physiology but by indirectly affecting the EPS constituents, and it helps to provide theoretical guidance for iron ion containing wastewater treatment.
A comparative study of the hydroxyl radical scavenging capacity of activated sludge and membrane bioreactor wastewater effluents
Authors: Grant Jacque-Ann , Hofmann Ron
Published: February 2016

This study evaluated the hydroxyl radical scavenging characteristics of wastewater from five membrane bioreactor (MBR) and five activated sludge (AS) systems. The average values of the characteristics of both wastewater types was found to be significantly different at a 90% confidence interval in terms UV absorbance at 254 nm, alkalinity, and biopolymer concentration. Effluent organic matter (EfOM), with an average kOH,EfOM of (2.75 ± 1.04) × 108 M−1s−1, was identified as the primary hydroxyl scavenger contributing to >70% of the background scavenging in all cases, except when nitrite exceeded 0.3 mg NO2−-N/L. The average scavenging capacity, EfOM scavenging capacity, and the EfOM reaction rate constant of the AS wastewaters exceeded that of the MBR. However, due to the small sample size (n = 5) and considerable variability in scavenging characteristics among the MBR wastewaters, the difference in EfOM reactivity between the two wastewaters was not statistically significant at a 90% confidence interval. Nevertheless, these preliminary findings suggest the possibility that MBR wastewaters may be more amenable to treatment by advanced oxidation. A plausible explanation is that MBRs were observed to reject biopolymers, and a strong correlation was observed between EfOM scavenging capacity and biopolymer concentration.
Determine the operational boundary of a pilot-scale single-stage partial nitritation/anammox system with granular sludge
Authors: Yang Yandong , Zhang Liang , Han Xiaoyu , Zhang Shujun , Li Baikun , Peng Yongzhen
Published: February 2016

The partial nitritation/anammox (PN/A) process has been applied to ammonium-rich wastewater treatment, but the operational boundary has not been well determined for long-term stability. This pilot-scale study was targeted at a single-stage PN/A process using a sequencing batch reactor (SBR) (volume: 53 m3) and granulated activated sludge. The maximum nitrogen removal rate reached 0.83 kg N/(m3 · d). Microbial analysis suggested that ammonium oxidizing bacteria were mainly present in small sludge flocs while anammox bacteria were prone to grow in large sludge granules. The PN/A performance was enhanced when dissolved oxygen (DO) was increased from 0.25 to 0.76 mg/L, and deteriorated at DO higher than 1.15 mg/L. The PN/A was inhibited at free ammonia (FA) over 77.0 mg/L. High DO or FA concentrations inhibited anammox activity and further induced high and inhibitory nitrite concentrations. Therefore, appropriate DO and FA concentrations should be controlled to achieve single-stage PN/A in SBRs.
Combating Diabetes Mellitus and Associated Oxidative Stress with Indigenous Medicinal Plants
Authors: Mitra Abhijit , Talukdar Anupam Das , Choudhury Manabendra Dutta , Nath Deepa , Ningthoujam Sanjoy Singh
Published: February 2016

Diabetes mellitus (DM) is an endocrine disorder affecting more than 100 million
people worldwide. It is exemplified by hyperglycemia caused by imperfect functioning of
insulin, abnormal insulin secretion or sometimes the combination of both. The long-term
persistence of high glucose concentrations in the blood leads to the generation of abnormally
high level of free radicals and reactive oxygen species (ROS), change of various oxidative
stress biomarker levels, simultaneous decline of antioxidant defense mechanisms and thereby
causes a variety of diabetic complications in the body. Increasing evidence in both
experimental and clinical studies suggests that oxidative stress plays a major role in the
pathogenesis of both types of diabetes mellitus. Abnormally increased production of free
radicals and the simultaneous decline of antioxidant defense mechanisms can lead to damage
of cellular organelles and enzymes, enhanced lipid peroxidation, and development of insulin
resistance, creating complicacies. Changes in oxidative stress biomarkers and their
consequences are discussed in this chapter. In vivo studies of the effects of various
conventional and alternative drugs on these biomarkers are surveyed. There is a need to
continue to explore the relationship between free radicals, diabetes, and its complications, and
to elucidate the mechanisms by which increased oxidative stress accelerates the development
of diabetic complications, in an effort to expand treatment options. Many ethnobotanically
important herbal plants possessing antihyperglycemic potential are known to exist in nature.
Moreover, a large number of polyherbal formulations (PHFs) derived from these plants are
presently being prescribed as medicinal/dietary supplements for the management of DM. It
has become very much essential to explore the hidden active principles present in the
traditionally used antidiabetic herbal plants in order to standardize the formulations of various
herbal drugs for the betterment of both types of DM treatment. This chapter would well
indicate about how oxidative stress is involved in the pathogenesis of diabetes and its
complications. The experimental validations and biochemical aspects of traditionally used
antidiabetic plants in phytotherapy of DM are discussed to understand and elucidate the
antidiabetic as well as associated antioxidative potentials.
Anti-Diabetic Effects of Plants Belonging to the Genus Senna: Pharmacology, Mechanism of Action and Phytochemistry
Authors: Ibrahim Mohammed Auwal , Islam Md. Shahidul
Published: February 2016

The genus Senna belongs to the family Leguminosae in the major group of
flowering plants (Angiosperms). Members of this genus are widely distributed in
different parts of the world and are mostly used for the traditional treatment of diabetes
mellitus. Scientific investigations have confirmed the anti-diabetic effects. In this
chapter, all the in vitro and in vivo anti-diabetic studies conducted on members of Senna
genus are critically reviewed with emphasis on the pharmacology, mechanism of antidiabetic
action and identified bioactive anti-diabetic agents in the plants. Among the
members of the genus, Senna auriculata, S. fistula and S. tora are perhaps the most
investigated. Other members of the genus investigated for anti-diabetic effects are S.
occidentalis, S. surratensis, S. angustifolia, S. singueana and S. siamae. Most of the
plants demonstrated potent anti-diabetic activity which is mediated via mechanisms
similar to conventional anti-diabetic drugs. Unfortunately, only few studies were
reported on the pure bioactive anti-diabetic agents but groups of phytochemicals were
postulated (as bioactive agents) for most of the studies. Findings from the in vitro and in
vivo anti-diabetic studies would be of interest for further research and subsequent
standardization (and commercialization) of anti-diabetic herbal remedy from some
members of Senna genus.
Monograph on Carum carvi L.
Authors: Moufid Abderrahmane , Farid Omar , Hebi Morad , Eddouks Mohamed
Published: February 2016

Plants have been highly valued for their healing properties in all cultures
around the world. The plant is widely used in food and traditional medicine from
ancient time. Carum carvi L. (C. carvi) is commonly known as spice and medicinal
plant in many cultures and several studies have reported that C. carvi possesses antidiabetic,
diuretic, antibacterial, antimicrobial, antiulcerogenic, antiproliferative and antispasmodic
activities. Phytochemical analyses have revealed that the main
phytochemicals in C. carvi seeds were carvone, limonene, carvacrol, carvenone, γ-
terpinene, and p-cymene. In this chapter, information about C. carvi including its
pharmacognosy, phytochemistry and pharmacology is provided.
Monograph on Premna serratifolia Linn.
Authors: Rani Smitha , Suriyaprakash T.N.K. , Prabu S. Lakshmana
Published: February 2016

Millions of people all over the world are using herbal medicines from
thousands of years, due to their great interest in traditional medicines and they believe
that herbal medicines are effective for the treatment of certain diseases. Premna
serratifolia L. is an important medicinal shrub used in traditional system of medicines
as antidiabetic, cardio tonic, antibiotic, anti-coagulant, carminative, hepatoprotective,
anti-tumor etc. The different parts of the plant like leaves, stem, stem barks, root, root
barks and wood have been used for extraction purpose. The chemical constituents or
secondary metabolites found are mainly alkaloids, terpenoids, phenolic compounds,
flavanoids and amino acids. The study suggests that the plant Premna serratifolia L. is a
potent source for phytomedicine development in the future.
Monograph on Eugenia jambolana. Lam.
Authors: Priya E. Sanmuga , Selvan P. Senthamil , Aakhil Anwar Syed Arshad
Published: February 2016

Eugenia jambolana. Lam. (EJ) is a plant belonging to Myrtaceace family.
Most of the plant parts of Eugenia jambolana are used in traditional system of medicine
in India. According to Ayurvedic scriptures, its bark is acrid, sweet, digestive and
astringent to the bowels. It is also anthelmintic and is good for sore throat, bronchitis,
asthma, thirst, biliousness, dysentery, blood impurities and to cure ulcers. Its
antidiabetic activity has been demonstrated both experimentally and clinically. In
addition, EJ has been demonstrated to exhibit several pharmacological properties
including anti-allergic, anti-oxidant, radioprotective, hepatoprotective, anti-ulcer,
antibacterial, anti-diarrhoeal, anti-hyperlipidemic, anti-depressant, nephroprotective and
chemopreventive activities. The health benefits of Eugenia jambolana are mainly
attributed to the various phytoconstituents, such as tannins, alkaloids, steroids,
flavonoids, terpenoids, fatty acids, phenols, minerals, carbohydrates and vitamins
present in the fruit. This chapter discusses the pharmacological and phytochemical
properties of this plant.
Preparing for imported Ebola cases in Israel, 2014 to 2015
Authors: Brosh-Nissimov Tal , Poles Lion , Kassirer Micha , Singer Roee , Kaliner Ehud , Shriki Dikla Dahan , Anis Emilia , Fogel Itay , Engelhard Dan , Grotto Itamar ,   on behalf of the Israeli Epidemic Management Team
Published: February 2016

During the current outbreak of Ebola virus disease (EVD) in West Africa, preventing exportation of the disease posed many challenges for economically more developed countries. In Israel, although the risk of importing single cases was assumed to be low, the implications of local transmission were great. This article describes the EVD preparedness plan of the Israeli Ministry of Health. Key elements were a sensitive case definition, designation of a single treatment centre for suspected and confirmed cases, construction of a mobile unit using customised negative-pressure tents and a vigorous national training programme. There were no patients with EVD in Israel, but a few suspected cases were assessed. The Israeli plan may provide a template for emergency infectious disease response in other geographically small countries.
Epidemiological investigation and case–control study: a Legionnaires’ disease outbreak associated with cooling towers in Warstein, Germany, August–September 2013
Authors: Maisa Anna , Brockmann Ansgar , Renken Frank , Lück Christian , Pleischl Stefan , Exner Martin , Daniels-Haardt Inka , Jurke Annette
Published: February 2016

Between 1 August and 6 September 2013, an outbreak of Legionnaires’ disease (LD) with 159 suspected cases occurred in Warstein, North Rhine-Westphalia, Germany. The outbreak consisted of 78 laboratory-confirmed cases of LD, including one fatality, with a case fatality rate of 1%. Legionella pneumophila, serogroup 1, subtype Knoxville, sequence type 345, was identified as the epidemic strain. A case–control study was conducted to identify possible sources of infection. In univariable analysis, cases were almost five times more likely to smoke than controls (odds ratio (OR): 4.81; 95% confidence interval (CI): 2.33–9.93; p < 0.0001). Furthermore, cases were twice as likely to live within a 3 km distance from one identified infection source as controls (OR: 2.14; 95% CI: 1.09–4.20; p < 0.027). This is the largest outbreak of LD in Germany to date. Due to a series of uncommon events, this outbreak was most likely caused by multiple sources involving industrial cooling towers. Quick epidemiological assessment, source tracing and shutting down of potential sources as well as rapid laboratory testing and early treatment are necessary to reduce morbidity and mortality. Maintenance of cooling towers must be carried out according to specification to prevent similar LD outbreaks in the future.
The utility of multiple molecular methods including whole genome sequencing as tools to differentiate Escherichia coli O157:H7 outbreaks
Authors: Berenger Byron M , Berry Chrystal , Peterson Trevor , Fach Patrick , Delannoy Sabine , Li Vincent , Tschetter Lorelee , Nadon Celine , Honish Lance , Louie Marie , Chui Linda
Published: February 2016

A standardised method for determining Escherichia coli O157:H7 strain relatedness using whole genome sequencing or virulence gene profiling is not yet established. We sought to assess the capacity of either high-throughput polymerase chain reaction (PCR) of 49 virulence genes, core-genome single nt variants (SNVs) or k-mer clustering to discriminate between outbreak-associated and sporadic E. coli O157:H7 isolates. Three outbreaks and multiple sporadic isolates from the province of Alberta, Canada were included in the study. Two of the outbreaks occurred concurrently in 2014 and one occurred in 2012. Pulsed-field gel electrophoresis (PFGE) and multilocus variable-number tandem repeat analysis (MLVA) were employed as comparator typing methods. The virulence gene profiles of isolates from the 2012 and 2014 Alberta outbreak events and contemporary sporadic isolates were mostly identical; therefore the set of virulence genes chosen in this study were not discriminatory enough to distinguish between outbreak clusters. Concordant with PFGE and MLVA results, core genome SNV and k-mer phylogenies clustered isolates from the 2012 and 2014 outbreaks as distinct events. k-mer phylogenies demonstrated increased discriminatory power compared with core SNV phylogenies. Prior to the widespread implementation of whole genome sequencing for routine public health use, issues surrounding cost, technical expertise, software standardisation, and data sharing/comparisons must be addressed.
Physiological and Structural Abnormalities of Coconut Plants (Cocos nucifera L.) at Different Stages of Growth and Plantation Sites under Low Temperature Condition in Bangladesh
Authors: Rashid M Mamunur , Hasan M Shamim , Rahman M H , Ahmmed Abu Noman Faruq , Khalequzzaman K M
Published: February 2016

Physiological and structural changes of coconut plants at different growth stages and plantation sites under low temperature conditions was investigated during 1997-98, 2002-03, 2005-06 and 2009-10 in the northern region of Bangladesh. Three growth stages viz. < 7, 7-15 and > 15 years and three locations viz. road side, near pond and near drain were selected for this study. Leaf area damage with characteristics lesions categorized into mildly damaged, moderately damaged and dead plants. Age and planting site revealed very significant differences. The highest percent of dead (49.84-58.49 %), moderately damaged (37.20-46.21 %) and mildly damaged plants (65.70-74.79 %) were found in road side, while the highest percent of dead plants (39.93-45.58 %), moderately (20.18-26.68 %) and mildly damaged plants (69.46-70.37 %) were found in above 15 years old plants. The lowest percent dead of plants (20.82, 18.27 and 19.55 %) were found in pond side and (11.74, 12.53 and 13.31 %) in the 7-15 years old plants. The mean temperature, sunshine hours and total precipitations remained below 16.88 °C, 10.25 hours and 11.7 cm, respectively during 1997-98, 2002-03 and 2009-10. The highest amount of potassium (0.57 me/100 g soil) was found in pond side soil, whereas the lowest amount of potassium (0.11 me/100g soil) was found in road side soil. It has been concluded that low temperature (below 16.88 °C), mean precipitation 11.7 cm and amount of potassium 0.11me/100 g in soil were responsible for severe damage of the coconut plants in the study area.The Agriculturists 2015; 13(2) 113-119
Resistance reduction on trimaran ship model by biopolymer of eel slime
Authors: Yanuar Y. , Gunawan G. , Talahatu M. A. , Indrawati R. T. , Jamaluddin A.
Published: February 2016

Resistance reduction in ship becomes an important issue to be investigated. Energy consumption and its efficiency are related toward drag reduction. Drag reduction in fluid flow can be obtained by providing polymer additives, coating, surfactants, fiber and special roughness on the surface hull. Fish skin surface coated with biopolymers viscous fluid (slime) is one method in frictional resistance reduction. The aim of this is to understanding the effect of drag reduction using eel slime biopolymer in unsymmetrical trimaran ship model. The Investigation was conducted using towing tank test with variation of velocity. The dimension of trimaran model are L = 2 m, B = 0.20 m and T = 0.065 m. The ship model resistance was precisely measured by a load cell transducer. The comparison of resistance on trimaran ship model coated and uncoated by eel slime are shown on the graph as a function of the total drag coefficient and Froude number. It is discovered the trimaran ship model by eel slime has higher drag reduction compared to trimaran with no eel slime at similar displacement. The result shows the drag reduction about 11 % at Fr 0.35.
Investigation of the mechanical properties of nanocomposite SWCNTS/epoxy by micromechanics methods and experimental works
Authors: Hedia H. S. , Aldousari S. M. , Abdellatif A. K. , Hafeez G. S. Abdel
Published: February 2016

In the present paper, the stiffening effect of carbon nanotubes is quantitatively investigated by micromechanics methods. The Mori-Tanaka effective-field method is employed to calculate the effective elastic moduli of composites with aligned or randomly oriented straight nanotubes. In addition, the epoxy resin is modified experimentally by adding SWCNT with different ratio i.e 0, 0.1, 0.3, 0.5 and 0.7 wt.-%. A comparison between the results for SWCNT/epoxy nanocomposite which obtained analytically and experimentally is done.In the experimental work the epoxy resin is modified by adding SWCNT with different ratio i.e 0, 0.1, 0.3, 0.5 and 0.7 wt.-%. The materials are characterized in tension to obtain the mechanical properties of SWCNT/epoxy nanocomposite experimentally. The results of micromechanics methods indicated that the CNTs are highly anisotropic, with Youngs modulus in the tube direction two orders of magnitude higher than that normal to the tube. The results shows a nanotube volume fraction of 0.3%of SWCNT improve all mechanical properties such as the tensile strength, modulus of elasticity and the toughness. Avoid the volume fraction greater than 0.5% SWCNT. The optimal value achieved experimentally, (at 0.3% SWCNT) lies between the analytical values (that achieved parallel to the CNT and the randomly orientated straight CNTs).
Le rôle des Pyrénées dans l'abondance de la Garonne toulousaine
Authors: Gazelle Francois
Published: February 2016

Papel de los Pirineos en el caudal del Garona hasta Toulouse. Los diversos estudios sobre el río Garona no destacan bastante el papel de « arca de agua » desempeñado por el macizo pirenaico. La parte montañosa de la cuenca-vertiente del Garona, extendida en una faja de unos 150 kilómetros por 20 o 30 de ancho, por las diversas altitudes, temperaturas y pluviometría, engendra caudales abundantes cuya influencia y fluctuaciones son notables, por no decir preponderantes, en gran parte del curso, del pedimonte a la confluencia con el río Tarn.
Le morcellement de la forêt dans la moyenne vallée de la Garonne
Authors: Lauga Jacques
Published: February 2016

Le morcellement forestier de la vallée de la Garonne consiste en une réduction de la superficie totale boisée doublée d'un émiettement des formations. Dans la zone étudiée, située au nord-ouest de Toulouse la couverture forestière n'est que de 4 %. Les effets biologiques de ce morcellement sont discutés, spécialement sur les oiseaux. Ils se traduisent surtout par un appauvrissement de la richesse biologique d'ensemble et par la disparition sélective de certaines espèces. La ripisylve des bords de la Garonne, mince ruban forestier, héberge en revanche une riche avifaune.
La qualité des eaux de la Garonne
Authors: Simonet François
Published: February 2016

La calidad de las aguas del rio Garona. Tras el examen de los medios de investigación de los que dispone la Agencia del Agua Adour-Garonne para elegir y cuantificar los parámetros de calidad de las aguas, son presentados los diversos tipos de contaminación y su origen local. En función de los resultados obtenidos de arriba para abajo, los tramos del río van clasificados en cuatro categorías. Gracias a las instalaciones de depuración de las aguas ya realizadas, se pueden fijar objetivos de calidad del Garona para el año 2000. Conviene espe- cialment limitar los riesgos de contaminación accidental (industrias) y el impacto de la contaminación difusa (agricultura).
A FORMATION SCENARIO FOR THE DISK OF SATELLITES: ACCRETION OF SATELLITES DURING MERGERS
Authors: Smith Rory , Duc Pierre Alain , Bournaud Frederic , Yi Sukyoung K.
Published: February 2016

The Disk of Satellites (DoS) observed in the Andromeda galaxy is a thin and extended group of satellites, nearly perpendicular to the disk plane, that share a common direction of rotation about the center of Andromeda. Although a DoS is also observed in the Milky Way galaxy, the prevalance of such structures in more distant galaxies remains controversial. Explanations for the formation of such DoSs vary widely from filamentary infall, or flattening due to the potential field from the large-scale structure, to galaxy interactions in a Mondian paradigm. Here we present an alternative scenario—during a merger, a galaxy may bring its own satellite population when merging with another galaxy. We demonstrate how, under the correct circumstances, during the coalescence of the two galaxies, the satellite population can be spread into an extended, flattened structure, with a common direction of rotation about the merger remnant. We investigate the key parameters of the interaction and the satellite population that are required to form a DoS in this scenario.
THE GLOBAL IMPLICATIONS OF THE HARD EXCESS. II. ANALYSIS OF THE LOCAL POPULATION OF RADIO-QUIET AGNs
Authors: Tatum M. M. , Turner T. J. , Miller L. , Reeves J. N. , DiLiello J. , Gofford J. , Patrick A. , Clayton M.
Published: February 2016

Active galactic nuclei (AGNs) show evidence for reprocessing gas, outflowing from the accreting black hole. The combined effects of absorption and scattering from the circumnuclear material likely explain the “hard excess” of X-ray emission above 20 keV, compared with the extrapolation of spectra from lower X-ray energies. In a recent Suzaku study, we established that the ubiquitous hard excess in hard, X-ray-selected, radio-quiet type 1 AGNs is consistent with a reprocessing of the X-ray continuum in an ensemble of clouds, located tens to hundreds of gravitational radii from the nuclear black hole. Here we add hard X-ray-selected, type 2 AGNs to extend our original study and show that the gross X-ray spectral properties of the entire local population of radio-quiet AGNs may be described by a simple unified scheme. We find a broad, continuous distribution of spectral hardness ratio and Fe Kα equivalent width across all AGN types, which can be reproduced by varying the observer's sightline through a single, simple model cloud ensemble, provided that the radiative transfer through the model cloud distribution includes not only photoelectric absorption but also three-dimensional (3D) Compton scattering. Variation in other parameters of the cloud distribution, such as column density or ionization, should be expected between AGNs, but such variation is not required to explain the gross X-ray spectral properties.
ON THE NATURE OF X-RAY SURFACE BRIGHTNESS FLUCTUATIONS IN M87
Authors: Arévalo P. , Churazov E. , Zhuravleva I. , Forman W. R. , Jones C.
Published: February 2016

X-ray images of galaxy clusters and gas-rich elliptical galaxies show a wealth of small-scale features that reflect fluctuations in density and/or temperature of the intracluster medium. In this paper we study these fluctuations in M87/Virgo to establish whether sound waves/shocks, bubbles, or uplifted cold gas dominate the structure. We exploit the strong dependence of the emissivity on density and temperature in different energy bands to distinguish between these processes. Using simulations we demonstrate that our analysis recovers the leading type of fluctuation even in the presence of projection effects and temperature gradients. We confirm the isobaric nature of cool filaments of gas entrained by buoyantly rising bubbles, extending to 7′ to the east and southwest, and the adiabatic nature of the weak shocks at 40″ and 3′ from the center. For features of ∼5–10 kpc, we show that the central 4′ × 4′ region is dominated by cool structures in pressure equilibrium with the ambient hotter gas while up to 30% of the variance in this region can be ascribed to adiabatic fluctuations. The remaining part of the central 14′ × 14′ region, excluding the arms and shocks described above, is dominated by apparently isothermal fluctuations (bubbles) with a possible admixture (at the level of ∼30%) of adiabatic (sound waves) and by isobaric structures. Larger features, of about 30 kpc, show a stronger contribution from isobaric fluctuations. The results broadly agree with a model based on feedback from an active galactic nucleus mediated by bubbles of relativistic plasma.
EFFECTS OF DYNAMICAL EVOLUTION OF GIANT PLANETS ON THE DELIVERY OF ATMOPHILE ELEMENTS DURING TERRESTRIAL PLANET FORMATION
Authors: Matsumura Soko , Brasser Ramon , Ida Shigeru
Published: February 2016

Recent observations started revealing the compositions of protostellar disks and planets beyond the solar system. In this paper, we explore how the compositions of terrestrial planets are affected by the dynamical evolution of giant planets. We estimate the initial compositions of the building blocks of these rocky planets by using a simple condensation model, and numerically study the compositions of planets formed in a few different formation models of the solar system. We find that the abundances of refractory and moderately volatile elements are nearly independent of formation models, and that all the models could reproduce the abundances of these elements of the Earth. The abundances of atmophile elements, on the other hand, depend on the scattering rate of icy planetesimals into the inner disk, as well as the mixing rate of the inner planetesimal disk. For the classical formation model, neither of these mechanisms are efficient and the accretion of atmophile elements during the final assembly of terrestrial planets appears to be difficult. For the Grand Tack model, both of these mechanisms are efficient, which leads to a relatively uniform accretion of atmophile elements in the inner disk. It is also possible to have a “hybrid” scenario where the mixing is not very efficient but the scattering is efficient. The abundances of atmophile elements in this case increase with orbital radii. Such a scenario may occur in some of the extrasolar planetary systems, which are not accompanied by giant planets or those without strong perturbations from giants. We also confirm that the Grand Tack scenario leads to the distribution of asteroid analogues where rocky planetesimals tend to exist interior to icy ones, and show that their overall compositions are consistent with S-type and C-type chondrites, respectively.
AN HST SURVEY OF THE HIGHEST-VELOCITY EJECTA IN CASSIOPEIA A*
Authors: Fesen Robert A. , Milisavljevic Dan
Published: February 2016

We present Hubble Space Telescope WFC3/IR images of the Cassiopeia A supernova remnant that survey its high-velocity, S-rich debris in the NE jet and SW counterjet regions through [S iii] λλ9069, 9531 and [S ii] λλ10,287–10,370 line emissions. We identify nearly 3400 sulfur emitting knots concentrated in ∼120° wide opposing streams, almost triple the number previously known. The vast majority of these ejecta knots lie at projected distances well out ahead of the remnant’s forward blast wave and main shell ejecta, extending to angular distance of

to the NE and

to the SW from the center of expansion. Such angular distances imply undecelerated ejecta knot transverse velocities of 15,600 and 12,700 km s−1, respectively, assuming an explosion date

AD and a distance of 3.4 kpc. Optical spectra of knots near the outermost tip of the NE ejecta stream show strong emission lines of S, Ca, and Ar. We estimate a total mass ∼0.1

and a kinetic energy of at least

erg for S-rich ejecta in the NE jet and SW counterjet. Although their broadness and kinetic energy argue against the Cas A SN being a jet-induced explosion, the jets are kinematically and chemically distinct from the rest of the remnant. This may reflect an origin in a jet-like mechanism that accelerated interior material from a Si-, S-, Ar-, and Ca-rich region near the progenitor’s core up through the mantle and H-, He-, N-, and O-rich outer layers with velocities that greatly exceeded that of the rapidly expanding photosphere.
FLASH SPECTROSCOPY: EMISSION LINES FROM THE IONIZED CIRCUMSTELLAR MATERIAL AROUND <10-DAY-OLD TYPE II SUPERNOVAE
Authors: Khazov D. , Yaron O. , Gal-Yam A. , Manulis I. , Rubin A. , Kulkarni S. R. , Arcavi I. , Kasliwal M. M. , Ofek E. O. , Cao Y. , Perley D. , Sollerman J. , Horesh A. , Sullivan M. , Filippenko A. V. , Nugent P. E. , Howell D. A. , Cenko S. B. , Silverman J. M. , Ebeling H. , Taddia F. , Johansson J. , Laher R. R. , Surace J. , Rebbapragada U. D. , Wozniak P. R. , Matheson T.
Published: February 2016

Supernovae (SNe) embedded in dense circumstellar material (CSM) may show prominent emission lines in their early-time spectra (≤10 days after the explosion), owing to recombination of the CSM ionized by the shock-breakout flash. From such spectra (“flash spectroscopy”), we can measure various physical properties of the CSM, as well as the mass-loss rate of the progenitor during the year prior to its explosion. Searching through the Palomar Transient Factory (PTF and iPTF) SN spectroscopy databases from 2009 through 2014, we found 12 SNe II showing flash-ionized (FI) signatures in their first spectra. All are younger than 10 days. These events constitute 14% of all 84 SNe in our sample having a spectrum within 10 days from explosion, and 18% of SNe II observed at ages <5 days, thereby setting lower limits on the fraction of FI events. We classified as “blue/featureless” (BF) those events having a first spectrum that is similar to that of a blackbody, without any emission or absorption signatures. It is possible that some BF events had FI signatures at an earlier phase than observed, or that they lack dense CSM around the progenitor. Within 2 days after explosion, 8 out of 11 SNe in our sample are either BF events or show FI signatures. Interestingly, we found that 19 out of 21 SNe brighter than an absolute magnitude M

R
 = −18.2 belong to the FI or BF groups, and that all FI events peaked above M

R
 = −17.6 mag, significantly brighter than average SNe II.
RE-INFLATED WARM JUPITERS AROUND RED GIANTS
Authors: Lopez Eric D. , Fortney Jonathan J.
Published: February 2016

Since the discovery of the first transiting hot Jupiters, models have sought to explain the anomalously large radii of highly irradiated gas giants. We now know that the size of hot Jupiter radius anomalies scales strongly with a planet's level of irradiation and numerous models like tidal heating, ohmic dissipation, and thermal tides have since been developed to help explain these inflated radii. In general, however, these models can be grouped into two broad categories: models that directly inflate planetary radii by depositing a fraction of the incident irradiation into the interior and models that simply slow a planet's radiative cooling, allowing it to retain more heat from formation and thereby delay contraction. Here we present a new test to distinguish between these two classes of models. Gas giants orbiting at moderate orbital periods around post-main-sequence stars will experience enormous increases to their irradiation as their host stars move up the sub-giant and red-giant branches. If hot Jupiter inflation works by depositing irradiation into the planet's deep interiors then planetary radii should increase in response to the increased irradiation. This means that otherwise non-inflated gas giants at moderate orbital periods of >10 days can re-inflate as their host stars evolve. Here we explore the circumstances that can lead to the creation of these “re-inflated” gas giants and examine how the existence or absence of such planets can be used to place unique constraints on the physics of the hot Jupiter inflation mechanism. Finally, we explore the prospects for detecting this potentially important undiscovered population of planets.
ON THE FATE OF UNSTABLE CIRCUMBINARY PLANETS: TATOOINE’S CLOSE ENCOUNTERS WITH A DEATH STAR
Authors: Sutherland Adam P. , Fabrycky Daniel C.
Published: February 2016

Circumbinary planets whose orbits become unstable may be ejected, accreted, or even captured by one of the stars. We quantify the relative rates of these channels, for a binary of secondary star’s mass fraction 0.1 with an orbit of 1 AU. The most common outcome is ejection, which happens ∼80% of the time. If binary systems form circumbinary planets readily and sloppily, this process may fill the Milky Way with free-floating planets. A significant fraction of the time, ∼20%, the unstable planet strikes the primary or secondary. We tracked whether a Jupiter-like planet would undergo tidal stripping events during close passages, and find that these events are rarely strong enough to capture the planet, although this may be observable via free-floating planets that are heated or spun-up by this process.
TILT ANGLE AND FOOTPOINT SEPARATION OF SMALL AND LARGE BIPOLAR SUNSPOT REGIONS OBSERVED WITH HMI
Authors: McClintock B. H. , Norton A. A.
Published: February 2016

We investigate bipolar sunspot regions and how tilt angle and footpoint separation vary during emergence and decay. The Helioseismic and Magnetic Imager on board the Solar Dynamic Observatory collects data at a higher cadence than historical records and allows for a detailed analysis of regions over their lifetimes. We sample the umbral tilt angle, footpoint separation, and umbral area of 235 bipolar sunspot regions in Helioseismic and Magnetic Imager—Debrecen Data with an hourly cadence. We use the time when the umbral area peaks as time zero to distinguish between the emergence and decay periods of each region and we limit our analysis of tilt and separation behavior over time to within ±96 hr of time zero. Tilt angle evolution is distinctly different for regions with small (≈30 MSH), midsize (≈50 MSH), and large (≈110 MSH) maximum umbral areas, with 45 and 90 MSH being useful divisions for separating the groups. At the peak umbral area, we determine median tilt angles for small (7.°6), midsize (5.°9), and large (9.°3) regions. Within ±48 hr of the time of peak umbral area, large regions steadily increase in tilt angle, midsize regions are nearly constant, and small regions show evidence of negative tilt during emergence. A period of growth in footpoint separation occurs over a 72-hr period for all of the regions from roughly 40 to 70 Mm. The smallest bipoles (<9 MSH) are outliers in that they do not obey Joy's law and have a much smaller footpoint separation. We confirm the Muñoz-Jaramillo et al. results that the sunspots appear to be two distinct populations.
THICK ACCRETION DISK MODEL FOR ULTRALUMINOUS SUPERSOFT SOURCES
Authors: Gu Wei-Min , Sun Mou-Yuan , Lu You-Jun , Yuan Feng , Liu Ji-Feng
Published: February 2016

We propose a geometrically thick, super-Eddington accretion disk model, where an optically thick wind is not necessary, to understand ultraluminous supersoft sources (ULSs). For high mass accretion rates

and not small inclination angles

, where

is the Eddington accretion rate, the hard photons from the hot inner region may be shaded by the geometrically thick inner disk, and therefore only the soft photons from the outer thin disk and the outer photosphere of the thick disk can reach the observer. Our model can naturally explain the approximate relation between the typical thermal radius and the thermal temperature,

. Moreover, the thick disk model can unify ULSs and normal ultraluminous X-ray sources, where the different observational characteristics are probably related to the inclination angle and the mass accretion rate. By comparing our model with the optically thick outflow model, we find that a lower mass accretion rate is required in our model.
A multi-laboratory comparison of two molecular methods for the detection of toxigenic Clostridium difficile
Authors: Halstead Diane C , Abid Joan , Sloan Lynne , Meza Diana , Ramsey-Walker Daphne , Hata Donna Jane
Published: January 2016

Introduction: Diarrheal disease due to toxigenic Clostridium difficile (CD) accounts for an increased number of hospitalizations and deaths each year. Published guidelines recommend reflex testing of CD antigen-positive samples to molecular testing or testing samples directly by a molecular assay. This multicenter study was designed to compare the accuracy of two different molecular methods targeting different CD genes: Xpert C. difficile Epi RUO RT-PCR assay (XPCR) which targets toxin B (Cepheid, Sunnyvale, CA) and a laboratory-developed PCR (LDPCR) which targets mutations in the tcdC regulatory gene. Methodology: Two molecular methods for toxigenic CD detection, the Xpert C. difficile Epi RUO RT-PCR assay (XPCR) [Cepheid, Sunnyvale, CA] and a laboratory-developed PCR assay (LDPCR) were compared to a consensus gold standard (CGS) or toxigenic culture (TC) as the reference method. A subset of specimens was subjected to additional molecular characterization of toxigenic CD. Results: Both molecular methods were >90% sensitive for CD detection. Discordant results were noted when molecular test results were compared to non-molecular methods. Supplemental molecular characterization illustrated inherent difficulties in comparisons using different molecular methods for CD. Conclusion: Laboratories may consider using multiple CD detection methods or combinations of methods, including molecular detection for rapid and accurate diagnosis of CD, as driven by best practices for the respective healthcare environment. Laboratories must be aware of intrinsic differences when comparing performance characteristics of different molecular assays.