Gamma-Ray Burst Progenitors

Levan, A.,Crowther, P.,Grijs, R.,Langer, N.,Xu, D.,Yoon, S. C. D. Reidel Pub. Co 2016 Space science reviews Vol.202 No.1

<P>We review our current understanding of the progenitors of both long and short duration gamma-ray bursts (GRBs). Constraints can be derived from multiple directions, and we use three distinct strands; (i) direct observations of GRBs and their host galaxies, (ii) parameters derived from modelling, both via population synthesis and direct numerical simulation and (iii) our understanding of plausible analog progenitor systems observed in the local Universe. From these joint constraints, we describe the likely routes that can drive massive stars to the creation of long GRBs, and our best estimates of the scenarios that can create compact object binaries which will ultimately form short GRBs, as well as the associated rates of both long and short GRBs. We further discuss how different the progenitors may be in the case of black hole engine or millisecond-magnetar models for the production of GRBs, and how central engines may provide a unifying theme between many classes of extremely luminous transient, from luminous and super-luminous supernovae to long and short GRBs.</P>

Positive biodiversity-productivity relationship predominant in global forests

Liang, Jingjing,Crowther, Thomas W.,Picard, Nicolas,Wiser, Susan,Zhou, Mo,Alberti, Giorgio,Schulze, Ernst-Detlef,McGuire, A. David,Bozzato, Fabio,Pretzsch, Hans,de-Miguel, Sergio,Paquette, Alain,H&eac American Association for the Advancement of Scienc 2016 Science Vol.354 No.6309

<P>The biodiversity-productivity relationship (BPR) is foundational to our understanding of the global extinction crisis and its impacts on ecosystem functioning. Understanding BPR is critical for the accurate valuation and effective conservation of biodiversity. Using ground-sourced data from 777,126 permanent plots, spanning 44 countries and most terrestrial biomes, we reveal a globally consistent positive concave-down BPR, showing that continued biodiversity loss would result in an accelerating decline in forest productivity worldwide. The value of biodiversity in maintaining commercial forest productivity alone-US$166 billion to 490 billion per year according to our estimation-is more than twice what it would cost to implement effective global conservation. This highlights the need for a worldwide reassessment of biodiversity values, forest management strategies, and conservation priorities.</P>

Regulating Access to Content in the European Union

Martin Cave,Peter Crowther 서울대학교 공익산업법센터 2011 경제규제와 법 Vol.4 No.1

[번역문] 유럽연합에서의 콘텐츠에 대한 접근의 규제

Martin Cave,Peter Crowther,황성기(번역자) 서울대학교 공익산업법센터 2011 경제규제와 법 Vol.4 No.1

이 글은 방송분야에서의 콘텐츠 접근에 관한 EU 경쟁법과 정책, 그리고 몇 가지 규제적 측면들을 검토하고 있다. 이 글은 먼저 콘텐츠 생성, 프로그램방송권(program rights)의 도매판매, 채널 패키징, 전달 또는 전송, 수익 창출 또는 소매판매로 구성되는 가치사슬 내에서 방송 콘텐츠의 위치를 설정한다. 이러한 구조적 틀 안에서 콘텐츠와 관련하여 두 종류의 경쟁법적 문제가 발생한다. 하나는 콘텐츠 생성 및 /또는 프로그램 도매시장의 독점화 문제이고 다른 하나는 프로그램 도매판매와 전달체계 사이의 (양쪽방향 모두) 시장지배력 전이(leveraging)의 문제이다. 유럽의 방송시장 분석의 출발점은 시장획정이다. 이 글은 유럽에서 다뤄진 경쟁법 사건들 중 프로그램 방송권과 관련하여 제기된 시장획정의 문제를 검토한다. 이러한 사건들에서 스포츠 방송권은, 보다 엄밀히 말하면 축구경기 방송권은 별개의 독립된 시장으로 정의된 바 있다. 유료방송 콘텐츠와 무료방송 콘텐츠 사이의 관계 역시 중요하다. 많은 유럽의 경쟁법 사건들은 스포츠 리그 클럽들의 방송권 일괄판매(collective selling)를 다루고 있다. 경쟁당국의 역할을 하는 유럽집행위원회는 방송판매기간을 제한하고, 방송권을 여러 개의 패키지로 분할하여 판매하게 하는 등 그러한 방송권의 판매행위에 대하여 다양한 규제를 해왔다. 할리우드 영화제작사들이 판매하는 영화방영권에 대해서도 다양한 규제를 하고 있다. 영국의 경우, 경쟁당국이 유료TV방송 지배사업자가 부과하는 소매가격과 동 사업자가 소매 경쟁사업자에게 부과하는 프로그램 도매가격 간의 가격 압착의 가능성을 조사하였다. 영국 경쟁당국은 분석을 위하여 개념상 방송사업자의 도매활동과 유통회사를 구별하였다. 분석결과는 경계선상에 위치하였으며, 당국은 남용을 입증할 만한 충분한 근거를 제시하지 못했다. 유럽에서는 유료TV방송사업자들의 기업결합의 조건으로 국가경쟁당국이나 유럽집행위원회가 결합된 방송사업자에게 대개는 다른 플랫폼 사업자인 실제 또는 잠재적 소매경쟁사업자에게 프로그램을 제공하도록 하고 있다. 이 경우 가격문제가 핵심문제이며, 가격에 대한 대안적 접근방법은 원가기반요금산정방식(cost-based prices), 소매요금 차감방식(retail minus prices) 그리고 협상에 근거한 방식 등이 있다. 대개는 분쟁해결절차가 사용된다. 이 글은 또한 영국의 규제당국이 유료TV방송 지배사업자에게 특정 프리미엄 스포츠 채널에 대한 접근을 소매경쟁사업자에게 허용하도록 한 현행 규제에 대하여 제기된 소송에 관한 배경설명도 포함하고 있다. 마지막으로, 유럽공동체의 규제방식은 적법한 공익을 목적으로 콘텐츠의 보편적 접근을 가능하도록 하기 위하여 전송서비스제공사업자에게 특정 채널을 전송할 의무를 부과할 수 있다. 이를 의무전송규칙(must-carry rules)이라고 한다. 방송사업자(일반적으로 공역무 방송사업자)에게 다른 플랫폼에 채널을 제공하도록 하는 의무제공규칙(must-offer rules)은 덜 일반적이다. 요컨대, 유럽의 방송 영역에서 가장 주요한 경쟁법적 현안은 방송권의 일괄판매와 도매시장의 지배사업자가 소유한 프로그램에 대한 의무적 접근의 문제이다. 그러나 비디오 콘텐츠 산업은 급변하고 있기 때문에 머지않아 새로운 쟁점들이 출현하게 될 것이다.

Development of Fast Prototyping Pneumatic Actuated Grippers

Nolan Jackson,Paul Chastain,Mitch Crowther,Minchul Shin 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.20 No.12

The goal of this paper is to develop biologically inspired soft robotic hands by using cheap commercial materials. Through finite elemental analysis and material testing, this paper shows effectiveness of a soft pneumatic finger for gripping and lifting. Using ANSYS simulations, the designs were analyzed in pressures, 0.0035 MPa and 0.007 MPa. This low pressure could output high deformations of the actuators. A single finger was able to withstand 25.3 N before failure, while being able to lift 15.3 g by itself under a low voltage air pump. When combing into a claw like gripper of four fingers it was able to lift roughly 8 times that of a single finger, around 130 g. This demonstration of a functional low-cost bio-inspired pneumatic finger showcases the potential for everyday use where a delicate touch is needed. Also, the high dexterity makes it a good design for use in manufacturing or medical areas.

Perioperative Anticoagulation in Patients with Mechanical Heart Valves Undergoing Elective Surgery: Results of a Survey Conducted among Korean Physicians

오도연,김세현,임창영,이종석,박선양,David Garcia,Mark A. Crowther,Walter Ageno 연세대학교의과대학 2005 Yonsei medical journal Vol.46 No.1

The optimal perioperative anticoagulation management in patients on warfarin therapy is poorly defined due to the lack of randomized trials. Because guidelines are heterogeneous, it was hypothesized that “treatment strategies are not uniform in clinical practice”. Between February 2003 and May 2003, a questionnaire with 4 different clinical scenarios was distributed to physicians by e-mail, or direct contact was made by a survey monitor. Two scenarios described the cases of patients with a mechanical heart valve (MHV) in the mitral position, with additional risk factors for a systemic embolism; one undergoing major (scenario 1) and the other minor surgery (scenario 3). Two scenarios described patients with an aortic MHV; one undergoing major (scenario 2) and the other minor (scenario 4) surgery. Different preoperative and postoperative management options were offered. The treatment options for all scenarios were the same. Of the 90 questionnaires distributed, 52 (57.8%) were returned. Hospitalization for full-dose intravenous unfractionated heparin (IV UH) was the most commonly selected strategy in the preoperative phase for scenarios 1 (59%), 2 (42%) and 3 (44%). In scenario 4, 34% chose IV UH. Outpatient, full- dose, subcutaneous UH or low-molecular-weight heparin (LMWH) was the most selected option in the postoperative phase for all scenarios, with the exception of number 4 (52.9% in scenario 1, 34% in scenario 2, 32%, in scenario 3 and 28% in scenario 4). Even among expert clinicians, the management of perioperative anticoagulation is heterogeneous. In particular, the definition of risk categories and the optimal intensity of antithrombotic drugs need to be defined by well-designed prospective studies.

Intratympanic Gentamicin Versus Labyrinthectomy: Inner Ear Sensitivity to Gentamicin and Impact on the Contralateral Labyrinth

Georgios Kontorinis,Hiteshkumar Tailor,Margaret Gaggin,John A. Crowther 대한이비인후과학회 2019 Clinical and Experimental Otorhinolaryngology Vol.12 No.4

Objectives. To investigate the impact of labyrinthectomy and intratympanic (IT) gentamicin injections on the contralateral labyrinth, we also assessed the response of each individual semicircular canal to each IT gentamicin application. Methods. We performed a pilot observational study on tertiary, referral, academic settings. Thirteen patients with unilateral vestibular pathology were organized into two groups, group I (seven patients) receiving IT gentamicin and group II undergoing labyrinthectomy (six patients). All patients underwent six-canal video-head-impulse test in predetermined time intervals. Patients receiving gentamicin were additionally tested 3 to 5 days after every sequential injection, until all ipsilateral canals were ablated, to determine the order of response to gentamicin. We recorded the vestibular-ocular reflex gains and the presence of covert/overt saccades for each canal. Results. The posttreatment ipsilateral gains were abnormal. No patient from the gentamicin group developed abnormal contralateral responses, while patients undergoing labyrinthectomy had abnormal contralateral responses from at least one canal, even several months posttreatment. Finally, the lateral semicircular canal was the first one to be affected by IT gentamicin followed by the posterior canal: the superior canal was ablated last. Conclusion. In our study, labyrinthectomy had an impact on the responses recorded from the contralateral ear, while IT gentamicin ablated the ipsilateral labyrinthine function without affecting the contralateral responses, possibly because of a milder, more gradual impact. We also show for the first time the order that IT gentamicin application affects the semicircular canals, with the lateral being the first to be affected.