bluuebunny/crossref_metadata_2025 huggingface dataset:
Transcranial magnetic resonance imaging–guided focused ultrasound thalamotomy for tremor: technical note
Authors: Wang Tony R. , Bond Aaron E. , Dallapiazza Robert F. , Blanke Aaron , Tilden David , Huerta Thomas E. , Moosa Shayan , Prada Francesco U. , Elias W. Jeffrey
Published: February 2018

Although the use of focused ultrasound (FUS) in neurosurgery dates to the 1950s, its clinical utility was limited by the need for a craniotomy to create an acoustic window. Recent technological advances have enabled efficient transcranial delivery of US. Moreover, US is now coupled with MRI to ensure precise energy delivery and monitoring. Thus, MRI-guided transcranial FUS lesioning is now being investigated for myriad neurological and psychiatric disorders. Among the first transcranial FUS treatments is thalamotomy for the treatment of various tremors. The authors provide a technical overview of FUS thalamotomy for tremor as well as important lessons learned during their experience with this emerging technology.
High-intensity focused ultrasound: past, present, and future in neurosurgery
Authors: Quadri Syed A. , Waqas Muhammad , Khan Inamullah , Khan Muhammad Adnan , Suriya Sajid S. , Farooqui Mudassir , Fiani Brian
Published: February 2018

Since Lynn and colleagues first described the use of focused ultrasound (FUS) waves for intracranial ablation in 1942, many strides have been made toward the treatment of several brain pathologies using this novel technology. In the modern era of minimal invasiveness, high-intensity focused ultrasound (HIFU) promises therapeutic utility for multiple neurosurgical applications, including treatment of tumors, stroke, epilepsy, and functional disorders. Although the use of HIFU as a potential therapeutic modality in the brain has been under study for several decades, relatively few neuroscientists, neurologists, or even neurosurgeons are familiar with it. In this extensive review, the authors intend to shed light on the current use of HIFU in different neurosurgical avenues and its mechanism of action, as well as provide an update on the outcome of various trials and advances expected from various preclinical studies in the near future. Although the initial technical challenges have been overcome and the technology has been improved, only very few clinical trials have thus far been carried out. The number of clinical trials related to neurological disorders is expected to increase in the coming years, as this novel therapeutic device appears to have a substantial expansive potential. There is great opportunity to expand the use of HIFU across various medical and surgical disciplines for the treatment of different pathologies. As this technology gains recognition, it will open the door for further research opportunities and innovation.
A review of potential applications of MR-guided focused ultrasound for targeting brain tumor therapy
Authors: Lamsam Layton , Johnson Eli , Connolly Ian D. , Wintermark Max , Hayden Gephart Melanie
Published: February 2018

Magnetic resonance–guided focused ultrasound (MRgFUS) has been used extensively to ablate brain tissue in movement disorders, such as essential tremor. At a lower energy, MRgFUS can disrupt the blood-brain barrier (BBB) to allow passage of drugs. This focal disruption of the BBB can target systemic medications to specific portions of the brain, such as for brain tumors. Current methods to bypass the BBB are invasive, as the BBB is relatively impermeable to systemically delivered antineoplastic agents. Multiple healthy and brain tumor animal models have suggested that MRgFUS disrupts the BBB and focally increases the concentration of systemically delivered antitumor chemotherapy, immunotherapy, and gene therapy. In animal tumor models, combining MRgFUS with systemic drug delivery increases median survival times and delays tumor progression. Liposomes, modified microbubbles, and magnetic nanoparticles, combined with MRgFUS, more effectively deliver chemotherapy to brain tumors. MRgFUS has great potential to enhance brain tumor drug delivery, while limiting treatment toxicity to the healthy brain.
Neuromodulation with transcranial focused ultrasound
Authors: Kubanek Jan
Published: February 2018

The understanding of brain function and the capacity to treat neurological and psychiatric disorders rest on the ability to intervene in neuronal activity in specific brain circuits. Current methods of neuromodulation incur a tradeoff between spatial focus and the level of invasiveness. Transcranial focused ultrasound (FUS) is emerging as a neuromodulation approach that combines noninvasiveness with focus that can be relatively sharp even in regions deep in the brain. This may enable studies of the causal role of specific brain regions in specific behaviors and behavioral disorders. In addition to causal brain mapping, the spatial focus of FUS opens new avenues for treatments of neurological and psychiatric conditions. This review introduces existing and emerging FUS applications in neuromodulation, discusses the mechanisms of FUS effects on cellular excitability, considers the effects of specific stimulation parameters, and lays out the directions for future work.
A meta-analysis of outcomes and complications of magnetic resonance–guided focused ultrasound in the treatment of essential tremor
Authors: Mohammed Nasser , Patra Devi , Nanda Anil
Published: February 2018

OBJECTIVE

Magnetic resonance–guided focused ultrasound (MRgFUS) is a novel technique that uses high-intensity focused ultrasound to achieve target ablation. Like a lens focusing the sun’s rays, the ultrasound waves are focused to generate heat. This therapy combines the noninvasiveness of Gamma Knife thalamotomy and the real-time ablation of deep brain stimulation with acceptable complication rates. The aim of this study was to analyze the overall outcomes and complications of MRgFUS in the treatment of essential tremor (ET).

METHODS

A meta-analysis in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was made by searching PubMed, Cochrane library database, Web of Science, and Cumulative Index to Nursing and Allied Health Literature (CINAHL). Patients with the diagnosis of ET who were treated with MRgFUS were included in the study. The change in the Clinical Rating Scale for Tremor (CRST) score after treatment was analyzed. The improvement in disability was assessed with the Quality of Life in Essential Tremor Questionnaire (QUEST) score. The pooled data were analyzed by the DerSimonian-Laird random-effects model. Tests for bias and heterogeneity were performed.

RESULTS

Nine studies with 160 patients who had ET were included in the meta-analysis. The ventral intermediate nucleus was the target in 8 of the studies. The cerebellothalamic tract was targeted in 1 study. There was 1 randomized controlled trial, 6 studies were retrospective, and 2 were prospective. The mean number of sonications given in various studies ranged from 11 ± 3.2 to 22.5 ± 7.5 (mean ± SD). The maximum delivered energy ranged from 10,320 ± 4537 to 14,497 ± 6695 Joules. The mean of peak temperature reached ranged from 53°C ± 2.3°C to 62.0°C ± 2.5°C. On meta-analysis with the random-effects model, the pooled percentage improvements in the CRST Total, CRST Part A, CRST Part C, and QUEST scores were 62.2%, 62.4%, 69.1%, and 46.5%, respectively. Dizziness was the most common in-procedure complication, occurring in 43.4%, followed by nausea and vomiting in 26.85% (pooled percentage). At 3 months, ataxia was the most common complication, occurring in 32.8%, followed by paresthesias in 25.1% of the patients. At 12 months posttreatment, the ataxia had significantly recovered and paresthesias became the most common persisting complication, at 15.3%.

CONCLUSIONS

The MRgFUS therapy for ET significantly improves the CRST scores and improves the quality of life in patients with ET, with an acceptable complication rate. Therapy with MRgFUS is a promising frontier in functional neurosurgery.
A minimally invasive catheter-based ultrasound technology for therapeutic interventions in brain: initial preclinical studies
Authors: Ghoshal Goutam , Gee Lucy , Heffter Tamas , Williams Emery , Bromfield Corinne , Rund Laurie , Ehrhardt John M. , Diederich Chris J. , Fischer Gregory S. , Pilitsis Julie G. , Burdette E. Clif
Published: February 2018

OBJECTIVE

Minimally invasive procedures may allow surgeons to avoid conventional open surgical procedures for certain neurological disorders. This paper describes the iterative process for development of a catheter-based ultrasound thermal therapy applicator.

METHODS

Using an ultrasound applicator with an array of longitudinally stacked and angularly sectored tubular transducers within a catheter, the authors conducted experimental studies in porcine liver, in vivo and ex vivo, in order to characterize the device performance and lesion patterns. In addition, they applied the technique in a rodent model of Parkinson’s disease to investigate the feasibility of its application in brain.

RESULTS

Thermal lesions with multiple shapes and sizes were readily achieved in porcine liver. The feasibility of catheter-based focused ultrasound in the treatment of brain conditions was demonstrated in a rodent model of Parkinson’s disease.

CONCLUSIONS

The authors show proof of principle of a catheter-based ultrasound system that can create lesions with concurrent thermode-based measurements.
Registration of Arkot 0705 and Arkot 0711 Cotton Germplasm Lines
Authors: Bourland Fred M. , Jones Don C.
Published: February 2018

Arkot 0705 (Reg. No. GP‐1033, PI 685636) and Arkot 0711 (Reg. No. GP‐1034, PI 685637) are conventional germplasm lines of cotton (Gossypium hirsutum L.) released by the Arkansas Agricultural Experiment Station in April 2017. The lines were released as part of an ongoing effort to develop improved genotypes having enhanced yield, yield components, earliness, host plant resistance, and fiber properties. Both Arkot 0705 and Arkot 0711 produced equal or higher lint yields than ‘DP 393’ and ‘UA48’ over 4 yr and at four test sites in Arkansas. Over all test sites, Arkot 0705 and Arkot 0711 produced 10.7 and 12.0%, respectively, higher lint yields than DP 393, and both produced over 20% more lint than UA48. Arkot 0705 has less dense stem pubescence and bract trichomes, higher lint percentage, higher lint index, and more fibers per seed than DP 393. Arkot 0711 differs from DP 393 having more dense leaf pubescence, less dense stem pubescence, lower bract trichome density, being earlier maturing, and having higher lint percentage, lint index, fibers per seed, and fiber density. Both lines displayed high resistance to bacterial blight and were similar to DP 393 in their response to other diseases and tarnished plant bugs. Fiber quality of the two lines was slightly lower than DP 393 and considerably lower than UA48.
'Atypical Localized Not Well-Specified Cases' a case study of a rare type of Localized Lichen Myxedematosus
Authors: Hye Mohammad A , Quyum Mohammad A , Begum Roushan A
Published: February 2018

Lichen Myxedematosus (LM) is an uncommon and distinct disease entity characterized by cutaneous mucin deposition in dermis. It is classified in several subtypes depending on many factors including the monoclonal gammapathy, pattern of skin involvement and systemic involvement. We now present a case of LM which is localized in respect of skin involvement but according to recent classification it falls into a diagnosis of 'atypical localized not well- specified cases'. This is a very rare case and to the best of our knowledge, it is the first case report in medical literature until now. We treated the case with a short course of oral Prednisolone and got excellent result. Patient has been followed up in every 6 month for last 13 yrs and observed no progression to scleromyxedema.Medicine Today 2018 Vol.30(1): 44-46
Les Barracs à Pierrefiche-d'Olt (Aveyron) : des tumulus accolés du Ve siècle avant J.-C
Authors: Gruat Philippe , Duday Henri , Marty Georges
Published: February 2018

The rescue excavation of a burial mound in the eastern Rouergue (Causses) demonstrated that it was the result of the agglomeration of three successive tumuli, indiscernible before the investigation. The cremated contents could be attributed to the Vth century B.C. The remnants, relatively abundant and partly recuperated from the ustrinum, show various influences and novel practices after inhumation. The protohistoric tombs have been put on top of, or modified, a level of Chalcolithic/Early Bronze occupation and graves from approximately the same period. One of these graves is a primary double inhumation, made directly in the earth and associated with what is probably a stela.
Un témoignage de la chute de la Confédération salyenne ? L'oppidum de Buffe Arnaud (Saint-Martin-de-Brômes, Alpes-de-Haute-Provence)
Authors: Garcia Dominique , Columeau Philippe , Duday Henri , Ecard Philippe , Guibal Frédéric , Bernard Loup
Published: February 2018

Recent preventive excavations led to the discovery of a hill-top habitat situated on the confluence of the Collostre and the Verdon in the Alpes-de-Hautes-Provence. Two phases of occupation were recognized ; the first attributed to the period 525-450 B.C. (construction in perishable material, hand-shaped pottery, few importations, etc.), the second to the period 225-125 B.C. The latter habitat is characterized by the presence of a wall provided with a gate-tower of an unusual type for southern Gaul, and by quarters arranged on terraces. Abundant objects allow a precise characterization of the aspect of the site which appears to be marked, as is the food production, by a crisis. The utter final destruction of this oppidum by fire, in the second half of the IInd century B.C. and the presence of catapult missiles allow to suppose that the site was abandoned in connexion with the campaigns of the Roman troops against the Salluvii in 124 B.C.
Coudounèu (Lançon-de-Provence, Bouches-du-Rhône) : une ferme-grenier et son terroir au Ve s. av. J.-C
Authors: Verdin Florence , Brien-Poitevin Françoise , Chabal Lucie , Marinval Philippe , Lippmann-Provansal Mireille
Published: February 2018

Le site de Coudounèu a été occupé durant la deuxième moitié du Ve s. av. J.-C. et détruit par un incendie entre la fin de ce siècle et le début du IVe s. L'exploration exhaustive des vestiges, de 1990 à 1992, et leur excellent état de conservation ont permis d'identifier un établissement fortifié à vocation agricole, d'une superficie de 1000 m2. Les bâtiments se composent de deux îlots séparés par une rue centrale et de quelques fonds de cabane creusés sur le sommet du rocher. La présence très nettement prédominante de récipients de stockage (doliums et vases en terre crue), associés à des graines carbonisées, montre que les bâtiments servaient de greniers. Quelques éléments de vaisselle et de parure n'excluent pas la présence d'une petite communauté résidant sur place. Les études paléoenvironnementales (carpologique, anthracologique, conchyologique et géomorphologique) permettent de replacer le site dans son contexte et d'appréhender son terroir agricole.
Nouveau regard sur le sanctuaire et les gravures de l'âge du Fer de l'oppidum des Caisses (Mouriès, B.-du-Rh)
Authors: Coignard Olivier , Coignard Roland , Marcadal Nadine , Marcadal Yves
Published: February 2018

L'enquête a porté sur un ensemble de 70 éléments lapidaires provenant du rempart de l'oppidum. Plusieurs types de critères ont été utilisés pour définir leur fonction : caractères morphologiques et technologiques, disposition des figurations par rapport à l'axe, organisation du champ figuratif. L'image du sanctuaire de la fin du premier âge du Fer ainsi obtenue est duale, avec un lieu construit (portique, murs) au sein d'un espace consacré en plein air peuplé de stèles votives. Celles-ci ont été façonnées par une multitude d'intervenants maîtrisant mal le travail de la pierre, mais certaines cependant sont l'œuvre de véritables professionnels. La formation d'une pellicule de calcin à la surface des documents est un argument en faveur d'une extraction en carrière des blocs, dès cette époque. Les gravures punctiformes (chevaux, motifs anthropomorphes) utilisent simultanément plusieurs procédés (dessin linéaire ou en double trait, champlevé, etc.) et un système de conventions allant du symbole à une tendance plus réaliste. Mais les cavités jusqu'alors interprétées comme des "cupules rituelles" sont dues à des phénomènes naturels d'altération.
Le tumulus du premier âge du Fer de Pontel à Dions (Gard)
Authors: Dedet Bernard , Gauthey Jacques , Pène Jean-Michel , Gardeisen Armelle
Published: February 2018

The excavation of the Pontel burial mound in 1996 and 1997 provides us with data relating to early Iron Age funerary practices in a region where most of the existing information is based on dated research. The sepulchral deposit of an adult on his back is on the natural soil, and is associated with burial goods (two incised vases, several shards and a piece of a bracelet, and dissarticulated bones from the hoofs of a calf and ribs from an Ovid were found in a pit). This pre-exists the built structures that could have been used in funerary rites. Teeth from other individuals ; an adult and a child of about 10-14 years of age, were scattered in two sets near the inhumation. Within the central area of the stones that form the burial mound several other elements were found, including an iron nail plus ovid and cattle bones, which could be indicative of another ceremonial phase.
Les meules des habitats protohistoriques de Martigues
Authors: Chausserie-Laprée Jean
Published: February 2018

Présentant de manière exhaustive et détaillée l'importante série (127 pièces cataloguées) d'objets de mouture issus des différents sites protohistoriques de Martigues, cette étude constitue pour la Provence occidentale le pendant des travaux menés naguère sur le même sujet pour le site de Lattes en Languedoc. Elle aborde la question d'un point de vue à la fois chronologique, technologique et fonctionnel et permet de suivre le mouvement d'innovations et de progrès techniques qui a marqué les sociétés gauloises de Martigues et de la Provence dans les pratiques quotidiennes de préparation alimentaire. En particulier l'existence de couples fonctionnels pour chaque grand type défini de meules, associée à une approche tracéologique des objets permet ici de mieux comprendre le mode d'utilisation des meules et parfois même de restituer des mécanismes jusque là inédits.
Abdominal Aortic Calcifications Predict Survival in Peritoneal Dialysis Patients
Authors: Mäkelä Satu , Asola Markku , Hadimeri Henrik , Heaf James , Heiro Maija , Kauppila Leena , Ljungman Susanne , Ots-Rosenberg Mai , Povlsen Johan V. , Rogland Björn , Roessel Petra , Uhlinova Jana , Vainiotalo Maarit , Svensson Maria K. , Huhtala Heini , Saha Heikki
Published: February 2018

Background

Peripheral arterial disease and vascular calcifications contribute significantly to the outcome of dialysis patients. The aim of this study was to evaluate the prognostic role of severity of abdominal aortic calcifications and peripheral arterial disease on outcome of peritoneal dialysis (PD) patients using methods easily available in everyday clinical practice.

Methods

We enrolled 249 PD patients (mean age 61 years, 67% male) in this prospective, observational, multicenter study from 2009 to 2013. The abdominal aortic calcification score (AACS) was assessed using lateral lumbar X ray, and the ankle-brachial index (ABI) using a Doppler device.

Results

The median AACS was 11 (range 0 – 24). In 58% of the patients, all 4 segments of the abdominal aorta showed deposits, while 19% of patients had no visible deposits (AACS 0). Ankle-brachial index was normal in 49%, low (< 0.9) in 17%, and high (> 1.3) in 34% of patients. Altogether 91 patients (37%) died during the median follow-up of 46 months. Only 2 patients (5%) with AACS 0 died compared with 50% of the patients with AACS ≥ 7 ( p < 0.001). The adjusted hazard ratio for all-cause mortality was 4.85 (95% confidence interval [CI] 1.94 – 24.46) for aortic calcification (AACS ≥ 7), 2.14 for diabetes (yes/no), 0.93 for albumin (per 1 g/L), and 1.04 for age (per year). A low or high ABI were not independently associated with mortality.

Conclusions

Severe aortic calcification was a strong predictor of all-cause mortality in PD patients. The evaluation of aortic calcifications by lateral X ray is a simple method that allows the identification of high-risk patients.
Increased Serum Lactate in Peritoneal Dialysis Patients Presenting with Intercurrent Illness
Authors: Trinh Emilie , Saiprasertkit Nalinee , Bargman Joanne M.
Published: February 2018

Background

Lactate is the most commonly used buffer in peritoneal dialysis (PD) solutions. While previous studies have shown that serum lactate is normal in stable PD patients, the purpose of our study was to evaluate whether abnormal lactate values are more common in PD patients presenting to the emergency department (ED) and have the same significance as in the general population.

Methods

This observational cohort study assessed the prevalence of elevated serum lactate in PD patients presenting to the ED and evaluated clinical factors associated with an abnormal lactate value.

Results

We studied 172 patient visits in 89 PD patients to the ED at a major academic center between January 1, 2015, and December 31, 2015. An initial venous blood lactate value was performed in 91 visits (53%) and was found to be elevated (> 2 mmol/L) in 26 cases (29%). While an abnormal lactate was associated with signs of hemodynamic compromise such as intensive care unit (ICU) admission (26.9% vs 10.8%, p = 0.05) and tachycardia (46.2% vs 9.2%, p < 0.01), in half of the cases with elevated lactate, there was no evidence of hemodynamic instability at initial presentation. Moreover, an abnormal lactate value was also associated with a greater likelihood of under going an abdominal computed tomography (CT) scan (46.2% vs 18.5%, p < 0.01), but bowel ischemia was present in only 1 case.

Conclusion

An abnormal lactate value is often seen in PD patients presenting to the ED, even in the absence of signs of hemodynamic instability, and very rarely indicates bowel ischemia. We postulate that in the setting of an acute intercurrent illness, there is a transient disruption in the metabolism of lactate absorbed from the PD fluid. This novel observation suggests that elevated serum lactate in the sick PD patient does not necessarily indicate tissue hypoperfusion or gut ischemia and may obviate unnecessary investigations.
Comprehensive Approach to Peritoneal Dialysis-Related Peritonitis by Enteric Microorganisms. Comparison between Single Organism and Polymicrobial Infections
Authors: Ribera-Sánchez Roi , Pérez-Fontán Miguel , López-Iglesias Antía , García-Enríquez Alba , Rodríguez-Carmona Ana
Published: February 2018

Background

Peritoneal infections of enteric origin (EntP) have been classically investigated using partial strategies, focused on particular subgroups of microorganisms. A more comprehensive approach may facilitate the definition of the nomenclature and clinical presentation of these infections.

Objectives

To investigate the clinical presentation and outcomes of a full spectrum of EntP, with a particular interest in the comparison between single-organism and polymicrobial infections.

Method

Following an observational design, we investigated 165 single-organism and 83 polymicrobial peritonitis episodes with isolation of at least 1 enteric bacteria ( Enterobacteriaceae, Enterococcus spp. and/or intestinal anaerobics). We compared the risk of treatment failure for these 2 types of infection and explored the significance of the isolation of specific microorganisms and of their antibacterial susceptibility patterns.

Results

Polymicrobial EntP was associated with higher rates of hospitalization, more changes to initial antibiotic therapy, more surgical explorations, and higher mortality and treatment failure rates than monobacterial EntP. However, stratified and multivariate analyses revealed that the burden of these differences rested on the isolation of intestinal anaerobics (odds ratio [OR] 12.05, 95% confidence interval [CI] 2.53–31.09, p < 0.001) and/or Enterococcus faecium (OR 3.37, 95% CI 1.02–11.30, p = 0.046), while other polymicrobial infections were more comparable with single-organism peritonitis, except for even higher mortality rates in the former group. Lower antibiotic susceptibility of the isolations (OR 1.18, 95% CI 0.51–2.70, p = 0.70) did not perform as a predictor of treatment failure.

Conclusion

A comprehensive approach to peritoneal infections by intestinal microorganisms may provide a focused perspective of the clinical presentation and outcomes of these complications of peritoneal dialysis.
Application of the Theory of Constraints in Project Based Structures
Authors: Sarapinas Martynas , Sūdžius Vytautas Pranas
Published: February 2018

The article deals with the application of the Theory of Constraints (TOC) in project management. This article involves a short introduction to TOC as a project management method and deep analysis of project management specialties using the TOC: TOC based project planning, timetable management, tasks synchronization, project control and “relay runner work ethic”. Moreover, the article describes traditional and TOC based project management theories in their comparison, and emphasize the main benefits we received as the results of the study.
PHOTOVOLTAIC CELLS / FOTOVOLTINIAI ELEMENTAI
Authors: Kiela Karolis
Published: February 2018

The article deals with an overview of photovoltaic cells that are currently manufactured and those being developed, including one or several p-n junction, organic and dye-sensitized cells using quantum dots. The paper describes the advantages and disadvantages of various photovoltaic cells, identifies the main parameters, explains the main reasons for the losses that may occur in photovoltaic cells and looks at the ways to minimize them.

Santrauka

Analizuojami rinkoje esantys ir ateityje į ją numatomi tiekti fotovoltiniai elementai: vienos, kelių p-n sandūrų, organiniai, dažais įjautrinti elementai su kvantiniais taškais. Aptariami jų privalumai ir trūkumai, įvardijami pagrindiniai fotovoltinius elementus aprašantys parametrai. Nurodomos pagrindinės dėl fotovoltinių elementų atsirandančių nuostolių priežastys ir būdai, kaip juos mažinti.
KELT-21b: A Hot Jupiter Transiting the Rapidly Rotating Metal-poor Late-A Primary of a Likely Hierarchical Triple System
Authors: Johnson Marshall C. , Rodriguez Joseph E. , Zhou George , Gonzales Erica J. , Cargile Phillip A. , Crepp Justin R. , Penev Kaloyan , Stassun Keivan G. , Gaudi B. Scott , Colón Knicole D. , Stevens Daniel J. , Strassmeier Klaus G. , Ilyin Ilya , Collins Karen A. , Kielkopf John F. , Oberst Thomas E. , Maritch Luke , Reed Phillip A. , Gregorio Joao , Bozza Valerio , Novati Sebastiano Calchi , D’Ago Giuseppe , Scarpetta Gaetano , Zambelli Roberto , Latham David W. , Bieryla Allyson , Cochran William D. , Endl Michael , Tayar Jamie , Serenelli Aldo , Aguirre Victor Silva , Clarke Seth P. , Martinez Maria , Spencer Michelle , Trump Jason , Joner Michael D. , Bugg Adam G. , Hintz Eric G. , Stephens Denise C. , Arredondo Anicia , Benzaid Anissa , Yazdi Sormeh , McLeod Kim K. , Jensen Eric L. N. , Hancock Daniel A. , Sorber Rebecca L. , Kasper David H. , Jang-Condell Hannah , Beatty Thomas G. , Carroll Thorsten , Eastman Jason , James David , Kuhn Rudolf B. , Labadie-Bartz Jonathan , Lund Michael B. , Mallonn Matthias , Pepper Joshua , Siverd Robert J. , Yao Xinyu , Cohen David H. , Curtis Ivan A. , DePoy D. L. , Fulton Benjamin J. , Penny Matthew T. , Relles Howard , Stockdale Christopher , Tan Thiam-Guan , Villanueva Steven
Published: February 2018

We present the discovery of KELT-21b, a hot Jupiter transiting the V = 10.5 A8V star HD 332124. The planet has an orbital period of P = 3.6127647 ± 0.0000033 days and a radius of

. We set an upper limit on the planetary mass of

at

confidence. We confirmed the planetary nature of the transiting companion using this mass limit and Doppler tomographic observations to verify that the companion transits HD 332124. These data also demonstrate that the planetary orbit is well-aligned with the stellar spin, with a sky-projected spin–orbit misalignment of

. The star has

K,

,

, and

km s−1, the highest projected rotation velocity of any star known to host a transiting hot Jupiter. The star also appears to be somewhat metal poor and α-enhanced, with

and [α/Fe] = 0.145 ± 0.053; these abundances are unusual, but not extraordinary, for a young star with thin-disk kinematics like KELT-21. High-resolution imaging observations revealed the presence of a pair of stellar companions to KELT-21, located at a separation of 1.″2 and with a combined contrast of

with respect to the primary. Although these companions are most likely physically associated with KELT-21, we cannot confirm this with our current data. If associated, the candidate companions KELT-21 B and C would each have masses of ∼0.12

, a projected mutual separation of ∼20 au, and a projected separation of ∼500 au from KELT-21. KELT-21b may be one of only a handful of known transiting planets in hierarchical triple stellar systems.
Turbulent Heating between 0.2 and 1 au: A Numerical Study
Authors: Montagud-Camps Victor , Grappin Roland , Verdini Andrea
Published: February 2018

The heating of the solar wind is key to understanding its dynamics and acceleration process. The observed radial decrease of the proton temperature in the solar wind is slow compared to the adiabatic prediction, and it is thought to be caused by turbulent dissipation. To generate the observed 1/R decrease, the dissipation rate has to reach a specific level that varies in turn with temperature, wind speed, and heliocentric distance. We want to prove that MHD turbulent simulations can lead to the 1/R profile. We consider here the slow solar wind, characterized by a quasi-2D spectral anisotropy. We use the expanding box model equations, which incorporate into 3D MHD equations the expansion due to the mean radial wind, allowing us to follow the plasma evolution between 0.2 and 1 au. We vary the initial parameters: Mach number, expansion parameter, plasma β, and properties of the energy spectrum as the spectral range and slope. Assuming turbulence starts at 0.2 au with a Mach number equal to unity, with a 3D spectrum mainly perpendicular to the mean field, we find radial temperature profiles close to 1/R on average. This is done at the price of limiting the initial spectral extent, corresponding to the small number of modes in the inertial range available, due to the modest Reynolds number reachable with high Mach numbers.
G331.512–0.103: An Interstellar Laboratory for Molecular Synthesis. I. The Ortho-to-para Ratios for CH3OH and CH3CN
Authors: Mendoza Edgar , Bronfman Leonardo , Duronea Nicolas U. , Lépine Jacques R. D. , Finger Ricardo , Merello Manuel , Hervías-Caimapo Carlos , Gama Diana R. G. , Reyes Nicolas , Åke-Nyman Lars
Published: February 2018

Spectral line surveys reveal rich molecular reservoirs in G331.512–0.103, a compact radio source in the center of an energetic molecular outflow. In this first work, we analyze the physical conditions of the source by means of CH3OH and CH3CN. The observations were performed with the APEX Telescope. Six different system configurations were defined to cover most of the band within (292–356) GHz; as a consequence, we detected a forest of lines toward the central core. A total of 70 lines of A/E–CH3OH and A/E–CH3CN were analyzed, including torsionally excited transitions of CH3OH (

). In a search for all the isotopologues, we identified transitions of 13CH3OH. The physical conditions were derived considering collisional and radiative processes. We found common temperatures for each A and E symmetry of CH3OH and CH3CN; the derived column densities indicate an A/E equilibrated ratio for both tracers. The results reveal that CH3CN and CH3OH trace a hot and cold component with

 K and

 K, respectively. In agreement with previous ALMA observations, the models show that the emission region is compact (

) with gas density n(H2) = (0.7–1)×107 cm−3. The CH3OH/CH3CN abundance ratio and the evidences for prebiotic and complex organic molecules suggest a rich and active chemistry toward G331.512–0.103.
Revisiting the Extended Schmidt Law: The Important Role of Existing Stars in Regulating Star Formation
Authors: Shi Yong , Yan Lin , Armus Lee , Gu Qiusheng , Helou George , Qiu Keping , Gwyn Stephen , Stierwalt Sabrina , Fang Min , Chen Yanmei , Zhou Luwenjia , Wu Jingwen , Zheng Xianzhong , Zhang Zhi-Yu , Gao Yu , Wang Junzhi
Published: February 2018

We revisit the proposed extended Schmidt law, which posits that the star formation efficiency in galaxies depends on the stellar mass surface density, by investigating spatially resolved star formation rates (SFRs), gas masses, and stellar masses of star formation regions in a vast range of galactic environments, from the outer disks of dwarf galaxies, to spiral disks and to merging galaxies, as well as individual molecular clouds in M33. We find that these regions are distributed in a tight power law as

 ∝ 

, which is also valid for the integrated measurements of disk and merging galaxies at high-z. Interestingly, we show that star formation regions in the outer disks of dwarf galaxies with

down to 10−5

yr−1 kpc−2, which are outliers of both the Kennicutt–Schmidt and Silk–Elmegreen laws, also follow the extended Schmidt law. Other outliers in the Kennicutt–Schmidt law, such as extremely metal-poor star formation regions, also show significantly reduced deviation from the extended Schmidt law. These results suggest an important role for existing stars in helping to regulate star formation through the effect of their gravity on the midplane pressure in a wide range of galactic environments.
Molecular Reconnaissance of the β Pictoris Gas Disk with the SMA: A Low HCN/(CO+CO2) Outgassing Ratio and Predictions for Future Surveys
Authors: Matrà L. , Wilner D. J. , Öberg K. I. , Andrews S. M. , Loomis R. A. , Wyatt M. C. , Dent W. R. F.
Published: February 2018

The exocometary origin of CO gas has been confirmed in several extrasolar Kuiper belts, with CO ice abundances consistent with solar system comets. We here present a molecular survey of the β Pictoris belt with the Submillimeter Array (SMA), reporting upper limits for CN, HCN, HCO+, N2H+, and H2CO, as well as for H2S, CH3OH, SiO, and DCN from archival ALMA data. Nondetections can be attributed to rapid molecular photodissociation due to the A-star’s strong UV flux. CN is the longest lasting and most easily detectable molecule after CO in this environment. We update our nonlocal thermodynamic equilibrium excitation model to include UV fluorescence, finding it plays a key role in CO and CN excitation, and we use it to turn the SMA CN/CO flux ratio constraint into an upper limit of

% on the HCN/(CO+CO2) ratio of outgassing rates. This value is consistent with, but at the low end of, the broad range observed in solar system comets. If sublimation dominates outgassing, then this low value may be caused by decreased outgassing for the less volatile molecule HCN compared to CO. If instead UV photodesorption or collisional vaporization of unbound grains dominates outgassing, then this low ratio of rates would imply a low ice abundance ratio, which would in turn indicate a variation in cometary cyanide abundances across planetary systems. To conclude, we make predictions for future molecular surveys and show that CN and HCN should be readily detectable with ALMA around β Pictoris for solar-system-like exocometary compositions.
Quenching or Bursting: The Role of Stellar Mass, Environment, and Specific Star Formation Rate to
Authors: Darvish Behnam , Martin Christopher , Gonçalves Thiago S. , Mobasher Bahram , Scoville Nick Z. , Sobral David
Published: February 2018

Using a novel approach, we study the quenching and bursting of galaxies as a function of stellar mass (M
*), local environment (Σ), and specific star formation rate (sSFR) using a large spectroscopic sample of ∼123,000 GALEX/SDSS and ∼420 GALEX/COSMOS/LEGA-C galaxies to z ∼ 1. We show that out to z ∼ 1 and at fixed sSFR and local density, on average, less massive galaxies are quenching, whereas more massive systems are bursting, with a quenching/bursting transition at

and likely a short quenching/bursting timescale (≲300 Myr). We find that much of the bursting of star formation happens in massive (

), high-sSFR galaxies (log(sSFR/Gyr−1) ≳ −2), particularly those in the field (log(Σ/Mpc−2) ≲0 and, among group galaxies, satellites more than centrals). Most of the quenching of star formation happens in low-mass (

), low-sSFR galaxies (log(sSFR/Gyr−1) ≲ −2), in particular those located in dense environments (log(Σ/Mpc−2) ≳1), indicating the combined effects of M
* and Σ in the quenching/bursting of galaxies since z ∼ 1. However, we find that stellar mass has stronger effects than environment on the recent quenching/bursting of galaxies to z ∼ 1. At any given M
*, sSFR, and environment, centrals are quenchier (quenching faster) than satellites in an average sense. We also find evidence for the strength of mass and environmental quenching being stronger at higher redshift. Our preliminary results have potential implications for the physics of quenching/bursting in galaxies across cosmic time.
Evolution of Photospheric Flow and Magnetic Fields Associated with the 2015 June 22 M6.5 Flare
Authors: Wang Jiasheng , Liu Chang , Deng Na , Wang Haimin
Published: February 2018

The evolution of photospheric flow and magnetic fields before and after flares can provide important information regarding the flare triggering and back-reaction processes. However, such studies on the flow field are rare due to the paucity of high-resolution observations covering the entire flaring period. Here we study the structural evolution of penumbra and shear flows associated with the 2015 June 22 M6.5 flare in NOAA AR 12371, using high-resolution imaging observation in the TiO band taken by the 1.6 m Goode Solar Telescope at Big Bear Solar Observatory, with the aid of the differential affine velocity estimator method for flow tracking. The accompanied photospheric vector magnetic field changes are also analyzed using data from the Helioseismic and Magnetic Imager. As a result, we found, for a penumbral segment in the negative field adjacent to the magnetic polarity inversion line (PIL), an enhancement of penumbral flows (up to an unusually high value of ∼2 km s−1) and extension of penumbral fibrils after the first peak of the flare hard X-ray emission. We also found an area at the PIL, which is co-spatial with a precursor brightening kernel, that exhibits a gradual increase of shear flow velocity (up to ∼0.9 km s−1) after the flare. The enhancing penumbral and shear flow regions are also accompanied by an increase of horizontal field and decrease of magnetic inclination angle (measured from the solar surface). These results are discussed in the context of the theory of back-reaction of coronal restructuring on the photosphere as a result of flare energy release.
Generation of Kappa Distributions in Solar Wind at 1 au
Authors: Livadiotis G. , Desai M. I. , Wilson L. B.
Published: February 2018

We examine the generation of kappa distributions in the solar wind plasma near 1 au. Several mechanisms are mentioned in the literature, each characterized by a specific relationship between the solar wind plasma features, the interplanetary magnetic field (IMF), and the kappa index—the parameter that governs the kappa distributions. This relationship serves as a signature condition that helps the identification of the mechanism in the plasma. In general, a mechanism that generates kappa distributions involves a single or a series of stochastic or physical processes that induces local correlations among particles. We identify three fundamental solar wind plasma conditions that can generate kappa distributions, noted as (i) Debye shielding, (ii) frozen IMF, and (iii) temperature fluctuations, each one prevailing in different scales of solar wind plasma and magnetic field properties. Moreover, our findings show that the kappa distributions, and thus, their generating mechanisms, vary significantly with solar wind features: (i) the kappa index has different dependence on the solar wind speed for slow and fast modes, i.e., slow wind is characterized by a quasi-constant kappa index, κ ≈ 4.3 ± 0.7, while fast wind exhibits kappa indices that increase with bulk speed; (ii) the dispersion of magnetosonic waves is more effective for lower kappa indices (i.e., further from thermal equilibrium); and (iii) the kappa and polytropic indices are positively correlated, as it was anticipated by the theory.
A Large Catalog of Multiwavelength GRB Afterglows. I. Color Evolution and Its Physical Implication
Authors: Li Liang , Wang Yu , Shao Lang , Wu Xue-Feng , Huang Yong-Feng , Zhang Bing , Ryde Felix , Yu Hoi-Fung
Published: February 2018

The spectrum of gamma-ray burst (GRB) afterglows can be studied with color indices. Here, we present a large comprehensive catalog of 70 GRBs with multiwavelength optical transient data on which we perform a systematic study to find the temporal evolution of color indices. We categorize them into two samples based on how well the color indices are evaluated. The Golden sample includes 25 bursts mostly observed by GROND, and the Silver sample includes 45 bursts observed by other telescopes. For the Golden sample, we find that 96% of the color indices do not vary over time. However, the color indices do vary during short periods in most bursts. The observed variations are consistent with effects of (i) the cooling frequency crossing the studied energy bands in a wind medium (43%) and in a constant-density medium (30%), (ii) early dust extinction (12%), (iii) transition from reverse-shock to forward-shock emission (5%), or (iv) an emergent SN emission (10%). We also study the evolutionary properties of the mean color indices for different emission episodes. We find that 86% of the color indices in the 70 bursts show constancy between consecutive ones. The color index variations occur mainly during the late GRB–SN bump, the flare, and early reverse-shock emission components. We further perform a statistical analysis of various observational properties and model parameters (spectral index

, electron spectral indices p
CI, etc.) using color indices. Overall, we conclude that ∼90% of colors are constant in time and can be accounted for by the simplest external forward-shock model, while the varying color indices call for more detailed modeling.
Communs en crise
Authors: Romagny Bruno , Aderghal Mohammed , Auclair Laurent , Ilbert Hélène , Lemeilleur Sylvaine
Published: February 2018

À travers les regards croisés de l’économie et de la géographie, et sur la base de plusieurs études de cas démonstratives des transformations en cours au Maroc des usages des ressources communautaires, à la fois endogènes et en lien avec des impulsions extérieures, l’objectif de cet article est d’interroger l’évolution de la notion de communs dans un contexte de crise de ces derniers. Est-il encore possible de parler de communs dans des situations où les communautés rurales se trouvent le plus souvent dessaisies, au profit de l’État et du secteur privé, des prérogatives qui étaient les leurs en matière de gouvernance locale de ressources collectives telles que l’eau agricole, les pâturages ou certaines forêts ? Cette réflexion nous amène à interroger le rôle actuel des pouvoirs publics marocains, notamment dans le cadre du Plan Maroc Vert, qui appuient l’émergence d’un mode d’organisation à vocation productiviste, négligeant trop souvent la préservation des ressources naturelles, des systèmes de gestion et des savoir-faire traditionnels collectifs.
Semences de blé ancien
Authors: Bucolo Elisabetta
Published: February 2018

La réflexion sur les communs apporte un éclairage significatif pour l’économie, le droit et la sociologie. En effet, elle ouvre des débats qui réhabilitent une pensée alternative à la doxa économique, au déterminisme juridique ainsi qu’à l’individualisme méthodologique. Ces approches nous aident à comprendre la capacité des acteurs à « agir ensemble » et à se mobiliser pour faire valoir des modes de gestion, de production et de consommation qui s’inscrivent dans le vécu de collectifs d’acteurs ou de communautés territoriales. Dans ce sens, nous nous sommes intéressés aux collectifs œuvrant à la préservation de variétés de semences de blé ancien en Sicile pour saisir les enjeux liés à ces initiatives et leurs apports dans le cadre du débat international sur la biodiversité et la souveraineté alimentaire.
Water, Energy, and Waste Services
Authors: Ranzato Marco , Moretto Luisa
Published: February 2018

The sustainable provision and access to water, energy, and waste services in urban areas are now being explored both as service coproduction and as an urban commons. This article aims at linking the reflection on these two streams of literature by investigating how the coproduction of urban water, energy, and waste services in the Global South can inform the reflection on the urban commons. The emphasis is on the spatiality and governance features attached to polycentrism, a concept key both to coproduction and commons.
En quête des communs urbains
Authors: Cavé Jérémie
Published: February 2018

Sur la base d’investigations empiriques dans l’agglomération de Vitória (Brésil), nous analysons ici la gestion conflictuelle des déchets urbains sous l’angle des biens communs. La mise en place du service public de collecte sélective suscite en effet des heurts entre les agents (publics et privés) du service municipal et les récupérateurs (formels et informels). À travers la mise en évidence de la dynamique propre à un bassin commun de ressources (BCR) ostromien, nous montrons qu’il peut être fécond d’appréhender le gisement urbain de déchets comme un BCR. Au-delà, la mobilisation de la notion de droits d’usage permet, à la lumière des initiatives de régulation à l’œuvre à Vitória, d’envisager un service semi-décentralisé des déchets.
Genèse d’un ouvrage collectif : le Dictionnaire des biens communs
Authors: Cornu Marie , Orsi Fabienne , Rochfeld Judith
Published: February 2018

Ce dictionnaire est né de la rencontre de juristes, d’économistes et d’historiens autour d’un projet de l’Agence nationale de la recherche (ANR) axé sur les communs de la connaissance. Cette recherche, entreprise sous une perspective pluridisciplinaire, impliquait tout d’abord de s’entendre sur les notions qu’utilise chaque discipline dans la réflexion sur les communs. Si nous sommes parties de l’approche développée par Elinor Ostrom et l’École de Bloomington, il ne s’est pas agi de réduire le champ de la confrontation à une seule notion de « commun », mais d’élargir à et de restituer toutes les notions de « commun » ainsi que les notions voisines ou concepts fondamentaux réinvestis à l’aune des communs. L’objectif était aussi de faire une place importante aux expériences novatrices, qu’elles soient savantes ou citoyennes.
M&A vs. Greenfield
Authors: Moid Sana
Published: February 2018

The chapter has raised two critically important questions. First, is the M&A boom a one-time effect of privatization, or is it likely to be followed by a rise in Greenfield investment? Second, do these two types of FDI mode have different macroeconomic consequences in terms of aggregate investment and growth? The main purpose of this chapter is to analyze the two entry modes, mergers and acquisitions and Greenfield investment, specifically, and to present a comparative view of the same and how it leads to the economic growth of a nation. It is concluded that one should choose the right mode according to the different situation about the firms in the international market. The present chapter also concludes that Greenfields and M&As do have a positive homogenous effect on growth. Additionally, the enhancement of human capital is an important condition for the host countries to derive the maximum benefits from Greenfields and M&As. Also, there is empirical evidence of a two-way linkage between FDI and growth. However, the bidirectional relationship exists only for the M&A's growth nexus.