bluuebunny/crossref_metadata_2025 huggingface dataset:
Hysteresis Compensation of Piezoresistive Carbon Nanotube/Polydimethylsiloxane Composite-Based Force Sensors
Authors: Kim Ji-Sik , Kim Gi-Woo
Published: January 2017

This paper provides a preliminary study on the hysteresis compensation of a piezoresistive silicon-based polymer composite, poly(dimethylsiloxane) dispersed with carbon nanotubes (CNTs), to demonstrate its feasibility as a conductive composite (i.e., a force-sensitive resistor) for force sensors. In this study, the potential use of the nanotube/polydimethylsiloxane (CNT/PDMS) as a force sensor is evaluated for the first time. The experimental results show that the electrical resistance of the CNT/PDMS composite changes in response to sinusoidal loading and static compressive load. The compensated output based on the Duhem hysteresis model shows a linear relationship. This simple hysteresis model can compensate for the nonlinear frequency-dependent hysteresis phenomenon when a dynamic sinusoidal force input is applied.
Decreasing Net Primary Productivity in Response to Urbanization in Liaoning Province, China
Authors: Chen Tan , Huang Qiuhao , Liu Miao , Li Manchun , Qu Le’an , Deng Shulin , Chen Dong
Published: January 2017

Regional ecosystems have been greatly affected by the rapid expansion of urban areas. In order to explore the impact of land use change on net primary productivity (NPP) in rapidly developing cities during the current urbanization process, we quantified land use change in Liaoning province between 2000 and 2010 using net primary productivity as an indicator of ecosystem productivity and health. The Carnegie–Ames–Stanford Approach model was used to estimate NPP by region and land use. We used a unit circle-based evaluation model to quantify local urbanization effects on NPP around eight representative cities. The dominant land use types were farmland, woodland and urban, with urban rapidly replacing farmland. Mean annual NPP and total NPP decreased faster from 2005 to 2010 than from 2000 to 2005, reflecting increasing urbanization rates. The eastern, primarily woodland part of Liaoning province had the greatest reduction in NPP, while the western part, which was primarily farmland and grassland, had the lowest reduction.
Environmental Sustainability: A Case of Policy Implementation Failure?
Authors: Howes Michael , Wortley Liana , Potts Ruth , Dedekorkut-Howes Aysin , Serrao-Neumann Silvia , Davidson Julie , Smith Timothy , Nunn Patrick
Published: January 2017

For a generation, governments around the world have been committed to sustainable development as a policy goal. This has been supported by an array of new policies ranging from international agreements, to national strategies, environmental laws at many levels of government, regional programs, and local plans. Despite these efforts, decades of scientific monitoring indicate that the world is no closer to environmental sustainability and in many respects the situation is getting worse. This paper argues that a significant contributing factor to this situation is policy implementation failure. A systematic review of the literature reveals that the failure to achieve the intended outcomes of environmental policies is due to economic, political and communication factors. Conflict between the objectives of environmental policies and those focused on economic development, a lack of incentives to implement environmental policies, and a failure to communicate objectives to key stakeholders are all key factors that contribute to the inability to attain environmental sustainability.
Efficiency Allocation of Provincial Carbon Reduction Target in China’s “13·5” Period: Based on Zero-Sum-Gains SBM Model
Authors: Guo Wen , Sun Tao , Dai Hongjun
Published: January 2017

Firstly, we introduce the “Zero Sum Gains” game theory into the SBM (Slacks-based Measure) model, and establish the ZSG-SBM model. Then, set up 4 development scenarios for the China’s economic system in “13·5” (The Chinese government formulates a Five-Year Planning for national economic and social development every five years, “13·5” means 2016 to 2020.) period through two dimensions as economic growth and energy consumption structure, and make the efficient allocation in provincial level of carbon reduction target by using the above ZSG-SBM model based on the China’s overall carbon reduction constraint (18%) which is set in “13·5” planning. Finally, we analyze the provincial development path of low-carbon economy by comparing the economic development status with the allocated result of carbon reduction target. Results show that: After the ZSG-SBM model being applied to the efficiency allocation of carbon emission, the input and output indicators of the 30 provinces realize the effective allocation, and the carbon emission efficiency reaches the efficiency frontier. The equity-oriented administrative allocation scheme of government will bring about efficiency loss in a certain degree, and the efficiency allocation scheme, based on the ZSG-SBM model, fits better with the long-term development requirement of low-carbon economy. On the basis of carbon intensity constraint, the re-constraint of energy intensity will force the provinces to optimize their energy consumption structure, thereby enhancing the overall carbon emission efficiency of China. Sixteen provinces’ allocation results of carbon reduction target are above China’s average (18%) in “13·5” period, all the provinces should select appropriate development path of low-carbon economy according to the status of their resource endowment, economic level, industrial structure and energy consumption structure.
New Coal-Fired Plants Jeopardise Paris Agreement
Authors: González-Eguino Mikel , Olabe Antxón , Ribera Teresa
Published: January 2017

Global greenhouse gas emissions need to peak soon and be reduced practically to zero in the second half of this century in order to not exceed the climate targets adopted in the Paris Agreement. However, there are currently numerous coal-fired power stations around the world at different stages of construction and planning that could be completed in the next decade. If all these plants are actually built, their expected future emissions will make it very difficult to reach these targets, even in an optimistic scenario with the deployment of carbon capture and storage technologies. Policy makers around the world need to react quickly and help to redirect investment plans for new coal-fired power stations towards low-carbon technologies.
Involvement of FvSet1 in Fumonisin B1 Biosynthesis, Vegetative Growth, Fungal Virulence, and Environmental Stress Responses in Fusarium verticillioides
Authors: Gu Qin , Tahir Hafiz , Zhang Hao , Huang Hai , Ji Tiantian , Sun Xiao , Wu Liming , Wu Huijun , Gao Xuewen
Published: January 2017

Fusarium verticillioides (teleomorph, Gibberella moniliformis) is an important plant pathogen that causes seedling blight, stalk rot, and ear rot in maize (Zea mays). During infection, F. verticillioides produce fumonsins B1 (FB1) that pose a serious threat to human and animal health. Recent studies showed that Set1, a methyltransferase of H3K4, was responsible for toxin biosynthesis in filamentous fungi. However, to date, the regulation of FvSet1 on FB1 biosynthesis remains unclear. In the current study, we identified only one Set1 ortholog in F. verticillioides (FvSet1) and found that the deletion of FvSET1 led to various defects in fungal growth and pathogenicity. More interestingly, the FvSET1 deletion mutant (ΔFvSet1) showed a significant defect in FB1 biosynthesis and lower expression levels of FUM genes. FvSet1 was also found to play an important role in the responses of F. verticillioides to multiple environmental stresses via regulating the phosphorylation of FvMgv1 and FvHog1. Taken together, these results indicate that FvSet1 plays essential roles in the regulation of FB1 biosynthesis, fungal growth and virulence, as well as various stress responses in F. verticillioides.
Shape Variation in the Craniomandibular System and Prevalence of Dental Problems in Domestic Rabbits: A Case Study in Evolutionary Veterinary Science
Authors: Böhmer Christine , Böhmer Estella
Published: January 2017

In contrast to wild lagomorphs, pet rabbits exhibit a noticeably high frequency of dental problems. Although dietary habits are considered as a major factor contributing to acquired malocclusions, the exact causes and interrelationships are still under debate. In this regard, an important aspect that has not been considered thoroughly to date is the effect of diet-induced phenotypic plasticity in skull morphology. Therefore, we conducted a geometric morphometric analysis on skull radiological images of wild and pet rabbits in order to quantify intraspecific variation in craniomandibular morphology. The statistical analyses reveal a significant morphological differentiation of the craniomandibular system between both groups. Furthermore, the analysis of covariance shows that the force-generating modules (cranium and mandible) vary independently from the force-receiving module (hypselodont teeth) in pet rabbits, which is in contrast to their wild relatives. Our findings suggest that the phenotypic changes in domestic rabbits impact mastication performance and, consequently, oral health. An adequate close-to-nature nutrition throughout the whole life and especially beginning early parallel to weaning (phase of increased phenotypic plasticity) is necessary to ensure a normal strain on the teeth by promoting physiological lateral gliding movements and avoiding direct axial loads.
La fructification d'Ascocybe grovesii Wells (=Cephaloascus fragans Hanawa) au microscope électronique
Authors: Besson Michèle
Published: January 2017

Les spores d 'Ascocybe grovesii sont semblables en tous points à celles du genre Pichia ; l'ascophore très particulier présente des pores septaux médians.
Une excursion entomologique à l'île de Quelpart (Cheju-do) et découverte d'une espèce nouvelle pour la Corée de Chrysolina Moltschulky (Col. Chrysomelidae). Réflexions sur la plantagophagie
Authors: Jolivet Pierre
Published: January 2017

Chrysolina staphylea, espèce nouvelle pour la Corée, vivant dans la région alpine du Mont Halla, île de Quelpart, a été découverte à l'intérieur et autour du cratère qui surmonte le volcan. La plante-hôte, in situ, est encore inconnue, mais en basse altitude et expérimentalement le plantain est parfaitement accepté. Cette espèce appartient vraisemblablement à un groupe boréo-alpin qui, sans aucun doute, a gagné cette île au début du pléistocène, au plus tard, quand un pont reliait la péninsule coréenne et l'île de Quelpart et quand la température était basse à cause des glaciations. Il faut remarquer que l'espèce a disparu du continent coréen, mais elle peut encore exister dans la zone alpine du Mont Giri, au sud, où peu ou pas de prospections entomologiques ont été effectuées. Lors des glaciations pléistocènes le hêtre disparut de Quelpart et de Corée continentale, mais a survécu à l'île de Dagelet dans la mer jaune. C'est à cette époque qu'il faut sans doute placer les migrations de C. staphylea vers Quelpart, île devenue par la suite subtropicale. La distribution de C. staphylea est actuellement holarctique froide.
Agrochola wautieri n. sp., espèce méconnue de Macédoine (Lep., Noctuidae Cucullinae)
Authors: Dufay Claude
Published: January 2017

Agrochola wautieri n. sp., espèce confondue jusqu'à présent avec Agrochola lactiflora Drdt. d'Anatolie orientale, est décrit d'après une série d'exemplaires capturés en Macédoine yougoslave. Il s'agit très probablement d'un endémique de cette région, comme d'autres Agrochola découverts il y a quelques années.
Agaricales rares ou nouvelles pour la région du Velay et ses environs
Authors: Bon M.
Published: January 2017

L'auteur décrit Pholiota (Flammula) Henningsii (Br.) Ort., Inocybe agardhii (Lund.) Ort., Phaeocollybia lateraria Sm., Ripartites strigiceps (Fr.) Karst., espèces rares ou nouvelles pour la région, peut-être même pour la France. Dermocybe vulcanica (proche de D. aureifolia Peck) et Amanitopsis submembranacea (proche d'A. inaurata Secr.) sont deux espèces nouvelles. Une section spéciale «Inauratae» est créée pour les Amanitopsis du groupe inaurata avec une clé concernant les trois espèces européennes. Enfin dans une courte note, l'existence d'Armillaria luteovirens, Tricholoma helviodor et divers Tricholomes, dont une variété nouvelle arvernensis (ad int.) de Tr. sejunctum, est signalée dans la dition. 5 planches en noir accompagnent le texte.
Diagnoses de 17 nouvelles espèces de Noctuidae d'Ethiopie et du Kenya (Lépidoptères)
Authors: Laporte Bernard
Published: January 2017

17 nouvelles espèces, 15 d'Ethiopie, 2 du Kenya, sont brièvement décrites ; il s'agit de cinq Noctuinae, de différents genres, un Cuculliinae, quatre Acronyctinae (dont deux du genre Eutamsia), quatre Catocalinae, un Stictoperinae et deux Ophiderinae.
Cochenilles des plantes cultivées en République Dominicaine (Homoptera, Coccoidea) (première liste)
Authors: Panis André , Martin H.E
Published: January 2017

Nine species of Coccids from Dominican Republic are discussed, with their host-plants. One poorly known species, Conchaspis cordiae Mamet, is found on Sea Grape and Mahogany but no morphological difference seems to happen, between specimens at hand from these two hosts.
Microflore des aiguilles de sapin Abies alba Mill. : Bactéries et levures
Authors: Faure-Raynaud M. , Gourbière G.
Published: January 2017

Mise en évidence de bactéries et levures sur les aiguilles de sapin Abies alba Mill. Evolution lors de la sénescence des aiguilles — variations saisonnières. Importance des bactéries dans cette microflore.
Une zoocécidie de la fleur de Polygonium convolvulus
Authors: Petrescu A.-D.
Published: January 2017

Après un rappel de quelques généralités sur les cécidies, spécialement des plantes du genre Polygonum, notamment en Roumanie, l'auteur étudie particulièrement une zoocécidie de la fleur de P. convolvulus, découverte par lui à Bucarest.

Cette galle, provoquée par un Microlépidoptère, ressemble à un ergot de Seigle, avec six carènes ; elle est habituellement de coloration verte, mais devient parfois rougeâtre vers la maturité.

Les sections transversales de cette zoocécidie montrent au centre une seule cavité où se développe la chenille ; dans la zone interne du parenchyme, s'observent six faisceaux libéro-ligneux.

L'analyse chimique de cette production végétale montre surtout la présence de tanin.

Dans quelques cas, il a été observé un hyperparasite, Diptère ou Hyménoptère, dont les larves se développent dans la galle aux dépens des stades jeunes du Lépidoptère cécidiogène.
Can 3D Gamified Simulations Be Valid Vocational Training Tools for Persons with Intellectual Disability?
Authors: von Barnekow Ariel , Bonet-Codina Núria , Tost Dani
Published: January 2017

Objective: To investigate if 3D gamified simulations can be valid vocational training tools for persons with intellectual disability.

Methods: A 3D gamified simulation composed by a set of training tasks for cleaning in hostelry was developed in collaboration with professionals of a real hostel and pedagogues of a special needs school. The learning objectives focus on the acquisition of vocabulary skills, work procedures, social abilities and risk prevention. Several accessibility features were developed to make the tasks easy to do from a technological point-of-view. A pilot experiment was conducted to test the pedagogical efficacy of this tool on intellectually disabled workers and students.

Results: User scores in the gamified simulation follow a curve of increasing progression. When confronted with reality, they recognized the scenario and tried to reproduce what they had learned in the simulation. Finally, they were interested in the tool, they showed a strong feeling of immersion and engagement, and they reported having fun.

Conclusions: On the basis of this experiment we believe that 3D gamified simulations can be efficient tools to train social and professional skills of persons with intellectual disabilities contributing thus to foster their social inclusion through work.
An Immersive Virtual Reality Platform to Enhance Walking Ability of Children with Acquired Brain Injuries
Authors: Beretta Elena , Cesareo Ambra , Maghini Cristina , Turconi Anna C. , Reni Gianluigi , Strazzer Sandra , Biffi Emilia
Published: January 2017

Background: Acquired brain injury (ABI) may result in lifelong impairment of physical, cognitive, and psychosocial functions. Several rehabilitative treatments are often needed to support walking recovery, thus participants’ engagement becomes a crucial aspect, especially when patients are children. In the last few years, traditional physiotherapy (PT) has been flanked by innovative technologies for rehabilitation in the fields of robotics and Virtual Reality (VR). Preliminary results have shown interesting perspectives in the use of a VR system, the GRAIL (Gait Real-time Analysis Interactive Lab), in improving walking abilities in a small group of children with ABI, although further insights are needed about its use as rehabilitative tool in the pediatric population.

Objectives: To evaluate the efficacy of a rehabilitation treatment on a GRAIL system for the improvement of walking abilities, in a group of children suffering from ABI.

Methods: 12 children with ABI (study group – SG; mean age = 12.1 ± 3.8 years old) underwent a 10-session treatment with the GRAIL, an instrumented multi-sensor platform based on immersive VR for gait training and rehabilitation in engaging VR environments. Before (T0) and at the end of the treatment (T1), the participants were assessed by means of functional scales (Gross Motor Function Measure (GMFM), Functional Assessment Questionnaire (FAQ), 6-Minute Walk Test (6minWT) and the 3D-Gait Analysis, over ground (OGA) and on GRAIL (GGA).

Results: All the participants completed the rehabilitative treatment. The functional evaluations showed an improvement in Gross Motor abilities (GMFM-88, p = 0.008), especially in standing (GMFM-D, p = 0.007) and walking (GMFM-E, p = 0.005), an increase of the endurance (6minWT, p = 0.002), and enhanced autonomy in daily life activities (FAQ, p = 0.025). OGA identified a significant decrease of the Gillette Gait Index for the impaired side and a general increase of symmetry. GGA showed improvements in spatiotemporal parameters and joints range of motion that moved towards normality and symmetry recovery.

Conclusions: A 10-session treatment with GRAIL on children with ABI led to improvements in their walking abilities and enhanced their engagement during the training. This is desirable when long life impairments are faced and children’s motor functions have to be regained and it supports the leading role that VR might have in the rehabilitation field.
Three Combined Treatments, a Novel HDAC Inhibitor OBP-801/YM753, 5-Fluorouracil, and Paclitaxel, Induce G2 Phase Arrest Through the p38 Pathway in Human Ovarian Cancer Cells
Authors: Akiyama Makoto , Sowa Yoshihiro , Taniguchi Tomoyuki , Watanabe Motoki , Yogosawa Shingo , Kitawaki Jo , Sakai Toshiyuki
Published: January 2017

Ovarian cancer is the most lethal disease among gynecological malignancies. More effective therapy is required to counter high recurrence rates and chemotherapy resistance. We investigated the efficacy and molecular mechanisms of three combined treatments (TCTs)—a novel histone
deacetylase (HDAC) inhibitor OBP-801/YM753, 5-fluorouracil (5-FU), and paclitaxel (PTX)—in human ovarian cancer SKOV-3 and OVCAR-3 cells. The inhibition of cell growth was stronger with TCTs than with each single agent and with two combined treatments. The TCTs significantly induce G2
phase arrest in both cell lines. We then analyzed the molecular mechanisms and found that the TCTs increased the phosphorylation of p38 (Thr180/Tyr182), decreased the expression of CDC25C, and increased the phosphorylation of CDC2 (Tyr15), an inactive form of CDC2. To examine the responsibilities
of the p38 pathway for G2 phase arrest induced by the TCTs, we employed the p38 inhibitor SB203580. SB203580 inhibited G2 phase arrest, suppression of CDC25C, and phosphorylation of CDC2 (Tyr15) induced by the TCTs. These results suggest that the TCTs can induce G2
phase arrest through activation of the p38 signaling pathway. We therefore believe that this combination is promising as a novel therapeutic strategy against ovarian cancer.
Self-optimisation and model-based design of experiments for developing a C–H activation flow process
Authors: Echtermeyer Alexander , Amar Yehia , Zakrzewski Jacek , Lapkin Alexei
Published: January 2017

A recently described C(sp3)–H activation reaction to synthesise aziridines was used as a model reaction to demonstrate the methodology of developing a process model using model-based design of experiments (MBDoE) and self-optimisation approaches in flow. The two approaches are compared in terms of experimental efficiency. The self-optimisation approach required the least number of experiments to reach the specified objectives of cost and product yield, whereas the MBDoE approach enabled a rapid generation of a process model.
Effects of the single supplementation and multiple doses of Passiflora incarnata L. on human anxiety: A Clinical Trial, Double-blind, Placebo-controlled, Randomized
Authors: Avelino da Silva Janilson , De Carvalho da Costa Maria José , Rodrigues da Alves Maria da Conceição , Fernandes da Braga João Euclides , Bezerra Luna da Lima Caliandra Maria , De Morais da Pordeus Liana Clébia
Published: January 2017

Object: This study aimed to investigate the effects of Passiflora incarnata L. on anxiety in humans.

Method: The individuals were randomly assigned to one of the following groups: Placebo or experimental, n =30, single dose, as well as Placebo or Experimental, n =15, multiple dose.  The experimental human anxiety was induced by simulated public speaking test in the following phases: Basal (B), stressful (A), speech 1 (S1), speech 2 (S2) and Final (F). We evaluated the Systolic Blood Pressure (SBP), and Diastolic (DBP), Heart Rate (HR), Electrical Conductance of Skin and extremities temperature (ET) and filled The state-trait anxiety inventory (STAI S e T).

Results: During the single dose, the HR was reduced at the end of the speech (86±2,0 to 74±3,0 bpm) the experimental group compared to the placebo group (p<0,05); the STAI-S did not change. In the delineation of multiple doses, SBP was reduced, in mmHg, in the experimental group compared to the placebo group during all phases. Experimental: 106±1,0 (B), 111±1,0 (A), 121±2,0 (S1), 115±3 (S2), 104±2,0 (F) e Placebo: 121±3,0; 127±3,0; 130±3,0; 130±4,5; 117±3,0 (p<0,05).

Conclusions: It is suggested that supplementation using Passiflora incarnata L. Capsules (500 mg) decreased cardiovascular signals both in single and in multiple doses, associated with the stress of public speaking.
Ejection of the Massive Hydrogen-rich Envelope Timed with the Collapse of the Stripped SN 2014C
Authors: Margutti Raffaella , Kamble A. , Milisavljevic D. , Zapartas E. , de Mink S. E. , Drout M. , Chornock R. , Risaliti G. , Zauderer B. A. , Bietenholz M. , Cantiello M. , Chakraborti S. , Chomiuk L. , Fong W. , Grefenstette B. , Guidorzi C. , Kirshner R. , Parrent J. T. , Patnaude D. , Soderberg A. M. , Gehrels N. C. , Harrison F.
Published: January 2017

We present multi-wavelength observations of SN 2014C during the first 500 days. These observations represent the first solid detection of a young extragalactic stripped-envelope SN out to high-energy X-rays ∼40 keV. SN 2014C shows ordinary explosion parameters (E
k ∼ 1.8 × 1051 erg and M
ej ∼ 1.7 M
⊙). However, over an ∼1 year timescale, SN 2014C evolved from an ordinary hydrogen-poor supernova into a strongly interacting, hydrogen-rich supernova, violating the traditional classification scheme of type-I versus type-II SNe. Signatures of the SN shock interaction with a dense medium are observed across the spectrum, from radio to hard X-rays, and revealed the presence of a massive shell of ∼1 M
⊙ of hydrogen-rich material at ∼6 × 1016 cm. The shell was ejected by the progenitor star in the decades to centuries before collapse. This result challenges current theories of massive star evolution, as it requires a physical mechanism responsible for the ejection of the deepest hydrogen layer of H-poor SN progenitors synchronized with the onset of stellar collapse. Theoretical investigations point at binary interactions and/or instabilities during the last nuclear burning stages as potential triggers of the highly time-dependent mass loss. We constrain these scenarios utilizing the sample of 183 SNe Ib/c with public radio observations. Our analysis identifies SN 2014C-like signatures in ∼10% of SNe. This fraction is reasonably consistent with the expectation from the theory of recent envelope ejection due to binary evolution if the ejected material can survive in the close environment for 103–104 years. Alternatively, nuclear burning instabilities extending to core C-burning might play a critical role.
Preconditioning of Interplanetary Space Due to Transient CME Disturbances
Authors: Temmer M. , Reiss M. A. , Nikolic L. , Hofmeister S. J. , Veronig A. M.
Published: January 2017

Interplanetary space is characteristically structured mainly by high-speed solar wind streams emanating from coronal holes and transient disturbances such as coronal mass ejections (CMEs). While high-speed solar wind streams pose a continuous outflow, CMEs abruptly disrupt the rather steady structure, causing large deviations from the quiet solar wind conditions. For the first time, we give a quantification of the duration of disturbed conditions (preconditioning) for interplanetary space caused by CMEs. To this aim, we investigate the plasma speed component of the solar wind and the impact of in situ detected interplanetary CMEs (ICMEs), compared to different background solar wind models (ESWF, WSA, persistence model) for the time range 2011–2015. We quantify in terms of standard error measures the deviations between modeled background solar wind speed and observed solar wind speed. Using the mean absolute error, we obtain an average deviation for quiet solar activity within a range of 75.1–83.1 km s−1. Compared to this baseline level, periods within the ICME interval showed an increase of 18%–32% above the expected background, and the period of two days after the ICME displayed an increase of 9%–24%. We obtain a total duration of enhanced deviations over about three and up to six days after the ICME start, which is much longer than the average duration of an ICME disturbance itself (∼1.3 days), concluding that interplanetary space needs ∼2–5 days to recover from the impact of ICMEs. The obtained results have strong implications for studying CME propagation behavior and also for space weather forecasting.
Triggered O Star Formation in M20 via Cloud–Cloud Collision: Comparisons between High-resolution CO Observations and Simulations
Authors: Torii K. , Hattori Y. , Hasegawa K. , Ohama A. , Haworth T. J. , Shima K. , Habe A. , Tachihara K. , Mizuno N. , Onishi T. , Mizuno A. , Fukui Y.
Published: January 2017

Understanding high-mass star formation is one of the top-priority issues in astrophysics. Recent observational studies have revealed that cloud–cloud collisions may play a role in high-mass star formation in several places in the Milky Way and the Large Magellanic Cloud. The Trifid Nebula M20 is a well-known Galactic H ii region ionized by a single O7.5 star. In 2011, based on the CO observations with NANTEN2, we reported that the O star was formed by the collision between two molecular clouds ∼0.3 Myr ago. Those observations identified two molecular clouds toward M20, traveling at a relative velocity of

. This velocity separation implies that the clouds cannot be gravitationally bound to M20, but since the clouds show signs of heating by the stars there they must be spatially coincident with it. A collision is therefore highly possible. In this paper we present the new CO J = 1–0 and J = 3–2 observations of the colliding clouds in M20 performed with the Mopra and ASTE telescopes. The high-resolution observations revealed that the two molecular clouds have peculiar spatial and velocity structures, i.e., a spatially complementary distribution between the two clouds and a bridge feature that connects the two clouds in velocity space. Based on a new comparison with numerical models, we find that this complementary distribution is an expected outcome of cloud–cloud collisions, and that the bridge feature can be interpreted as the turbulent gas excited at the interface of the collision. Our results reinforce the cloud–cloud collision scenario in M20.
The Origin of the Near-infrared Excess in SN Ia 2012dn: Circumstellar Dust around the Super-Chandrasekhar Supernova Candidate
Authors: Nagao Takashi , Maeda Keiichi , Yamanaka Masayuki
Published: January 2017

The nature of progenitors of the so-called super-Chandrasekhar candidate Type Ia supernovae (SC-SNe Ia) has been actively debated. Recently, Yamanaka et al. reported a near-infrared (NIR) excess for SN 2012dn and proposed that the excess originates from an echo by circumstellar (CS) dust. In this paper, we examine a detailed distribution of the CS dust around SN 2012dn and investigate implications of the CS dust echo scenario for general cases of SC-SNe Ia. We find that a disk/bipolar CS medium configuration reproduces the NIR excess fairly well, where the radial density distribution is given by a stationary mass loss. The inner radius of the CS dust is 0.04 pc. The mass-loss rate of the progenitor system is estimated to be

and

M
⊙ yr−1 for the disk and bipolar CS medium configurations, respectively, which adds further support for the single-degenerate scenario. Our models limit SN 2009dc, another SC-SN Ia, to have a dust mass less than 0.16 times that of SN 2012dn. While this may merely indicate some variation on the CS environment among SC-SNe Ia, this could raise another interesting possibility. There could be two classes among SC-SNe Ia: the brighter SC-SNe Ia in a clean environment (SN 2009dc) and the fainter SC-SNe Ia in a dusty environment (SN 2012dn).
iPTF Discovery of the Rapid “Turn-on” of a Luminous Quasar
Authors: Gezari S. , Hung T. , Cenko S. B. , Blagorodnova N. , Yan Lin , Kulkarni S. R. , Mooley K. , Kong A. K. H. , Cantwell T. M. , Yu P. C. , Cao Y. , Fremling C. , Neill J. D. , Ngeow C.-C. , Nugent P. E. , Wozniak P.
Published: January 2017

We present a radio-quiet quasar at z = 0.237 discovered “turning on” by the intermediate Palomar Transient Factory (iPTF). The transient, iPTF 16bco, was detected by iPTF in the nucleus of a galaxy with an archival Sloan Digital Sky Survey spectrum with weak narrow-line emission characteristic of a low-ionization nuclear emission-line region (LINER). Our follow-up spectra show the dramatic appearance of broad Balmer lines and a power-law continuum characteristic of a luminous (

erg s−1) type 1 quasar 12 yr later. Our photometric monitoring with PTF from 2009–2012 and serendipitous X-ray observations from the XMM-Newton Slew Survey in 2011 and 2015 constrain the change of state to have occurred less than 500 days before the iPTF detection. An enhanced broad Hα/[O iii] λ5007 line ratio in the type 1 state relative to other changing-look quasars also is suggestive of the most rapid change of state yet observed in a quasar. We argue that the >10 increase in Eddington ratio inferred from the brightening in UV and X-ray continuum flux is more likely due to an intrinsic change in the accretion rate of a preexisting accretion disk than an external mechanism such as variable obscuration, microlensing, or the tidal disruption of a star. However, further monitoring will be helpful in better constraining the mechanism driving this change of state. The rapid “turn-on” of the quasar is much shorter than the viscous infall timescale of an accretion disk and requires a disk instability that can develop around a

black hole on timescales less than 1 yr.
Internal Gravity Waves in the Magnetized Solar Atmosphere. I. Magnetic Field Effects
Authors: Vigeesh G. , Jackiewicz J. , Steiner O.
Published: January 2017

Observations of the solar atmosphere show that internal gravity waves are generated by overshooting convection, but are suppressed at locations of magnetic flux, which is thought to be the result of mode conversion into magnetoacoustic waves. Here, we present a study of the acoustic-gravity wave spectrum emerging from a realistic, self-consistent simulation of solar (magneto)convection. A magnetic field free, hydrodynamic simulation and a magnetohydrodynamic (MHD) simulation with an initial, vertical, homogeneous field of 50 G flux density were carried out and compared with each other to highlight the effect of magnetic fields on the internal gravity wave propagation in the Sun’s atmosphere. We find that the internal gravity waves are absent or partially reflected back into the lower layers in the presence of magnetic fields and argue that the suppression is due to the coupling of internal gravity waves to slow magnetoacoustic waves still within the high-β region of the upper photosphere. The conversion to Alfvén waves is highly unlikely in our model because there is no strongly inclined magnetic field present. We argue that the suppression of internal waves observed within magnetic flux concentrations may also be due to nonlinear breaking of internal waves due to vortex flows that are ubiquitously present in the upper photosphere and the chromosphere.
Application of the Nonballistic Model to the Black Hole Candidate XTE J1752-223 and the Quasar NRAO 150
Authors: Zheng T. Y. , Gong B. P.
Published: January 2017

Optical and radio observations of the black hole candidate XTE J1752-223 have exhibited a slightly curved motion of the jet components, which is associated with its radio light curve. In addition, observations of the quasar NRAO 150 have revealed a core–jet structure wobbling with a high angular speed. In this paper, the phenomena displayed in these two different sources are interpreted as the precession of a bent jet. In such a scenario, hot spots reproduced at different separations from the core precess on the same precession cone, in which different components correspond to different propagation times to the observer. By fitting the kinematics of the components of XTE J1752-223 and its light curve with a curved pattern of precession period 314 days, we find that the propagation time can make an earlier event appear later, and the jet axis can oscillate during its precession. Simulating the quasar NRAO 150 with the same scenario reveals that the knots at larger separation from the core precess at a slower speed than those closer in. A possible mechanism relating to the cooling time of a component is proposed. These three new results are of importance in understanding the physics underlying the curved jet as well as the activity of the central engine of different black hole systems.
AR Sco: A Precessing White Dwarf Synchronar?
Authors: Katz J. I.
Published: January 2017

The emission of the white dwarf–M dwarf binary AR Sco is driven by the rapid synchronization of its white dwarf, rather than by accretion. Synchronization requires a magnetic field ∼100 Gauss at the M dwarf and

Gauss at the white dwarf, larger than the fields of most intermediate polars but within the range of fields of known magnetic white dwarfs. The spindown power is dissipated in the atmosphere of the M dwarf, within the near zone of the rotating white dwarf’s field, by magnetic reconnection, accelerating particles that produce the observed synchrotron radiation. The displacement of the optical maximum from conjunction may be explained either by dissipation in a bow wave as the white dwarf’s magnetic field sweeps past the M dwarf or by a misaligned white dwarf rotation axis and oblique magnetic moment. In the latter case the rotation axis precesses with a period of decades, predicting a drift in the orbital phase of the optical maximum. Binaries whose emission is powered by synchronization may be termed synchronars, in analogy to magnetars.
Testing Metal-poor Stellar Models and Isochrones with HST Parallaxes of Metal-poor Stars
Authors: Chaboyer B. , McArthur B. E. , O’Malley E. , Benedict G. F. , Feiden G. A. , Harrison T. E. , McWilliam A. , Nelan E. P. , Patterson R. J. , Sarajedini A.
Published: January 2017

Hubble Space Telescope (HST) fine guidance sensor observations were used to obtain parallaxes of eight metal-poor ([Fe/H] < −1.4) stars. The parallaxes of these stars determined by the new Hipparcos reduction average 17% accuracy, in contrast to our new HST parallaxes, which average 1% accuracy and have errors on the individual parallaxes ranging from 85 to 144 μas. These parallax data were combined with HST Advanced Camera for Surveys photometry in the F606W and F814W filters to obtain the absolute magnitudes of the stars with an accuracy of 0.02–0.03 mag. Six of these stars are on the main sequence (MS) (with −2.7 < [Fe/H] < −1.8) and are suitable for testing metal-poor stellar evolution models and determining the distances to metal-poor globular clusters (GCs). Using the abundances obtained by O’Malley et al., we find that standard stellar models using the VandenBerg & Clem color transformation do a reasonable job of matching five of the MS stars, with HD 54639 ([Fe/H] = −2.5) being anomalous in its location in the color–magnitude diagram. Stellar models and isochrones were generated using a Monte Carlo analysis to take into account uncertainties in the models. Isochrones that fit the parallax stars were used to determine the distances and ages of nine GCs (with −2.4 ≤ [Fe/H] ≤ −1.9). Averaging together the age of all nine clusters led to an absolute age of the oldest, most metal-poor GCs of 12.7 ± 1.0 Gyr, where the quoted uncertainty takes into account the known uncertainties in the stellar models and isochrones, along with the uncertainty in the distance and reddening of the clusters.
Galaxy Environment in the 3D-HST Fields: Witnessing the Onset of Satellite Quenching at z ∼ 1–2
Authors: Fossati M. , Wilman D. J. , Mendel J. T. , Saglia R. P. , Galametz A. , Beifiori A. , Bender R. , Chan J. C. C. , Fabricius M. , Bandara K. , Brammer G. B. , Davies R. , Förster Schreiber N. M. , Genzel R. , Hartley W. , Kulkarni S. K. , Lang P. , Momcheva I. G. , Nelson E. J. , Skelton R. , Tacconi L. J. , Tadaki K. , Übler H. , van Dokkum P. G. , Wisnioski E. , Whitaker K. E. , Wuyts E. , Wuyts S.
Published: January 2017

We make publicly available a catalog of calibrated environmental measures for galaxies in the five 3D-Hubble Space Telescope (HST)/CANDELS deep fields. Leveraging the spectroscopic and grism redshifts from the 3D-HST survey, multiwavelength photometry from CANDELS, and wider field public data for edge corrections, we derive densities in fixed apertures to characterize the environment of galaxies brighter than

mag in the redshift range

. By linking observed galaxies to a mock sample, selected to reproduce the 3D-HST sample selection and redshift accuracy, each 3D-HST galaxy is assigned a probability density function of the host halo mass, and a probability that it is a central or a satellite galaxy. The same procedure is applied to a z = 0 sample selected from Sloan Digital Sky Survey. We compute the fraction of passive central and satellite galaxies as a function of stellar and halo mass, and redshift, and then derive the fraction of galaxies that were quenched by environment specific processes. Using the mock sample, we estimate that the timescale for satellite quenching is

it is longer at lower stellar mass or lower redshift, but remarkably independent of halo mass. This indicates that, in the range of environments commonly found within the 3D-HST sample (

), satellites are quenched by exhaustion of their gas reservoir in the absence of cosmological accretion. We find that the quenching times can be separated into a delay phase, during which satellite galaxies behave similarly to centrals at fixed stellar mass, and a phase where the star formation rate drops rapidly (

Gyr), as shown previously at z = 0. We conclude that this scenario requires satellite galaxies to retain a large reservoir of multi-phase gas upon accretion, even at high redshift, and that this gas sustains star formation for the long quenching times observed.
Origin and Properties of Quiet-time 0.11–1.28 MeV Nucleon−1 Heavy-ion Population Near 1 au
Authors: Dayeh M. A. , Desai M. I. , Mason G. M. , Ebert R. W. , Farahat A.
Published: January 2017

Using measurements from the Advanced Composition Explorer/Ultra-Low Energy Isotope Spectrometer near 1 au, we surveyed the composition and spectra of heavy ions (He-through-Fe) during quiet times from 1998 January 1 to 2015 December 31 at suprathermal energies between ∼0.11 and ∼1.28 MeV nucleon−1. The selected time period covers the maxima of solar cycles 23 and 24 and the extended solar minimum in between. We find the following. (1) The number of quiet hours in each year correlates well with the sunspot number, year 2009 was the quietest for about 82% of the time. (2) The composition of the quiet-time suprathermal heavy-ion population (3He, C-through-Fe) correlates well with the level of solar activity, exhibiting SEP-like composition signatures during solar maximum, and CIR- or solar wind-like composition during solar minimum. (3) The heavy-ion (C–Fe) spectra exhibit suprathermal tails at energies of 0.11–0.32 MeV nucleon−1 with power-law spectral indices ranging from 1.40 to 2.97. Fe spectra soften (steepen, i.e., spectral index increases) smoothly with increasing energies compared with Fe, indicating a rollover behavior of Fe at higher energies (0.45–1.28 MeV nucleon−1). (4) Spectral indices of Fe and O do not appear to exhibit clear solar cycle dependence. (2) and (3) imply that during IP quiet times and at energies above ∼0.1 MeV nucleon−1, the IP medium is dominated by material from prior solar and interplanetary events. We discuss the implications of these extended observations in the context of the current understanding of the suprathermal ion population near 1 au.
Le chaînon manquant ? Les modèles institutionnels pour expliquer l’évolution du 1 % le plus riche
Authors: Zorn Nicolas
Published: January 2017

Depuis le milieu des années 1980, la part des revenus captée par le 1 % le plus riche des pays développés a connu deux tendances distinctes ; les pays anglophones ont vécu une hausse importante alors que les pays non anglophones ont plutôt connu une hausse modérée et parfois même un recul. Les facteurs institutionnels (sans lien avec l’aspect linguistique) permettent le mieux d’expliquer ces différentes évolutions. Or, l’importance des institutions dans l’économie serait avant tout de nature combinatoire. Comme le soulignent les théories des modèles/variétés de capitalisme, une même institution n’aura pas nécessairement le même impact dans un contexte institutionnel différent, et deux combinaisons différentes d’institutions peuvent produire des effets similaires. Nous postulons que les modèles institutionnels permettent d’expliquer l’évolution du 1 % le plus riche. Ce texte examine la compatibilité des facteurs institutionnels identifiés par la littérature avec quatre théories de modèles institutionnels différenciant les pays anglophones des autres pays développés. Cette approche ajoute un élément important dans la compréhension de l’évolution des hauts revenus.
Recent Economic Developments and the Implications for Fiscal Policy in Open Economy Macroeconomics
Authors: Zeyneloğlu İrem , Koenig Gilbert
Published: January 2017

Cet article présente et commente les apports récents de la macroéconomie internationale à l’analyse de la politique budgétaire face à trois évolutions économiques de ces dernières années : l’intégration internationale croissante des marchés, la crise de la dette publique et l’émergence d’une union monétaire, comme celle de l’Europe. Ces apports se placent dans le cadre de modèles d’équilibre général à deux pays. Le processus d’intégration internationale croissante des marchés financiers et des marchés de biens a suscité des travaux qui reconsidèrent l’impact de ce processus sur les incidences économiques de la politique budgétaire. En second lieu, la crise de la dette publique qui se manifeste dans la plupart des pays développés a conduit à une analyse de la politique budgétaire fondée sur une meilleure gestion des dépenses publiques et à la spécification d’une expansion budgétaire qui internalise la nécessité de préserver le caractère soutenable du déficit et de l’endettement public. En troisième lieu, la création de l’Union monétaire européenne et la récente crise économique globale ont suscité l’intérêt pour les gains potentiels que peuvent générer la stabilisation et la coopération budgétaires et stimulé les recherches sur la combinaison optimale des politiques budgétaires et monétaires dans un cadre dynamique et stochastique.
Rueff, Allais, et le chômage d’équilibre
Authors: Prat Georges
Published: January 2017

Le concept de chômage « permanent » proposé par Rueff [1925, 1931] représente une forme de chômage d’équilibre attribuable à une rigidité salariale à la baisse conduisant à un excès persistant du salaire réel par rapport à sa valeur correspondant à un équilibre concurrentiel. Eu égard à cet aspect connu des travaux de l’auteur sur le sujet, cet article montre que Rueff considérait aussi la possibilité d’un chômage « temporaire » dû à un niveau insuffisant de l’activité économique et d’un chômage « minimal » de type frictionnel prévalant dans le fonctionnement normal de toute économie. Sur la base d’une étude empirique, l’auteur soutenait que le chômage « permanent » constituait la cause majeure du chômage dans l’Angleterre des années 1920 ( « loi de Rueff » ). Nous présentons des tests économétriques simples sur les données utilisées par Rueff confirmant cette conclusion, tout en montrant que le relâchement de l’hypothèse d’une productivité du travail constante (admise par Rueff) permet d’améliorer la précision de la « loi de Rueff » . Dans le droit fil de ces résultats, nous montrons que l’analyse théorique d’Allais [1943] repose sur les trois types de chômage évoqués par Rueff, qualifiés désormais respectivement de « chronique » , « conjoncturel » et « technologique » . Bien plus tard, Allais [1980] a proposé une équation économétrique méconnue intégrant ces trois composantes du chômage et montré que cette dernière décrit l’évolution du chômage français au cours des années 1952-78. Nous montrons que cette équation peut aussi représenter les grands traits des évolutions du chômage anglais des années 1920 et du chômage français des années 1970-2008, mais aussi qu’elle présente un défaut de spécification. Enfin, sous certaines conditions restrictives, nous suggérons que les trois types de chômage distingués par Rueff et Allais peuvent être vus sous le prisme du taux de chômage d’équilibre déduit d’une version simple du modèle de concurrence imparfaite WS-PS (Layard-Nickel-Jackman [1991]), cet exercice indiquant des raisons plausibles au défaut de spécification constatés sur l’équation simple d’Allais, mettant ainsi en évidence les importants progrès scientifiques accomplis depuis.