2,768 research outputs found
Quasi-Rip: A New Type of Rip Model without Cosmic Doomsday
The fate of our universe is an unceasing topic of cosmology and the human
being. The discovery of the current accelerated expansion of the universe
significantly changed our view of the fate of the universe. Recently, some
interesting scenarios concerning the fate of the universe attracted much
attention in the community, namely the so-called "Little Rip" and "Pseudo-Rip".
It is worth noting that all the Big Rip, Little Rip and Pseudo-Rip arise from
the assumption that the dark energy density is monotonically
increasing. In the present work, we are interested to investigate what will
happen if this assumption is broken, and then propose a so-called "Quasi-Rip"
scenario, which is driven by a type of quintom dark energy. In this work, we
consider an explicit model of Quasi-Rip in detail. We show that Quasi-Rip has
an unique feature different from Big Rip, Little Rip and Pseudo-Rip. Our
universe has a chance to be rebuilt from the ashes after the terrible rip. This
might be the last hope in the "hopeless" rip.Comment: 9 pages, 2 figures, 1 table, revtex4; v2: discussions added, Phys.
Rev. D in press; v3: published versio
Arterialisation of the Portal Vein With an Aortoportal Jump Graft for Portal Vein Thrombosis Following Liver Resection for Malignancy
Fibrolamellar hepatocellular carcinoma (FHCC) is a
variant of hepatocellular carcinoma, which mainly affects
a young age group and carries a relatively good
prognosis. It is widely accepted that aggressive curative
resection is still the best option for FHCC. We
report here a case of successful arterialisation of the
portal vein with an aortoportal jump graft for portal
vein thrombosis, which developed postoperatively in
an already comprised portal vein with tumour invasion
following an extensive liver resection for FHCC
Fast micro-differential evolution for topological active net optimization
This paper studies the optimization problem of topological active net (TAN), which is often seen in image segmentation and shape modeling. A TAN is a topological structure containing many nodes, whose positions must be optimized while a predefined topology needs to be maintained. TAN optimization is often time-consuming and even constructing a single solution is hard to do. Such a problem is usually approached by a ``best improvement local search'' (BILS) algorithm based on deterministic search (DS), which is inefficient because it spends too much efforts in nonpromising probing. In this paper, we propose the use of micro-differential evolution (DE) to replace DS in BILS for improved directional guidance. The resultant algorithm is termed deBILS. Its micro-population efficiently utilizes historical information for potentially promising search directions and hence improves efficiency in probing. Results show that deBILS can probe promising neighborhoods for each node of a TAN. Experimental tests verify that deBILS offers substantially higher search speed and solution quality not only than ordinary BILS, but also the genetic algorithm and scatter search algorithm
Differential evolution with an evolution path: a DEEP evolutionary algorithm
Utilizing cumulative correlation information already existing in an evolutionary process, this paper proposes a predictive approach to the reproduction mechanism of new individuals for differential evolution (DE) algorithms. DE uses a distributed model (DM) to generate new individuals, which is relatively explorative, whilst evolution strategy (ES) uses a centralized model (CM) to generate offspring, which through adaptation retains a convergence momentum. This paper adopts a key feature in the CM of a covariance matrix adaptation ES, the cumulatively learned evolution path (EP), to formulate a new evolutionary algorithm (EA) framework, termed DEEP, standing for DE with an EP. Without mechanistically combining two CM and DM based algorithms together, the DEEP framework offers advantages of both a DM and a CM and hence substantially enhances performance. Under this architecture, a self-adaptation mechanism can be built inherently in a DEEP algorithm, easing the task of predetermining algorithm control parameters. Two DEEP variants are developed and illustrated in the paper. Experiments on the CEC'13 test suites and two practical problems demonstrate that the DEEP algorithms offer promising results, compared with the original DEs and other relevant state-of-the-art EAs
Choice of court agreements in international civil and commercial law: a comparative study of Chinese law, the 2005 Hague Choice of Court Convention and the Brussels I Recast Regulation
This dissertation focuses on choice of court agreements in international civil and commercial law. It introduces the terminology regarding choice of court agreements, describes different types of choice of court agreements, and examines the scopes of choice of court agreements in Chapter 2. Based on the principle of party autonomy, choice of court agreements have been an important basis of jurisdiction in many legal systems. This dissertation undertakes a detailed examination of choice of court agreements in three legal contexts, namely, Chinese law, the 2005 Hague Choice of Court Convention and the Brussels I Recast Regulation, in Chapter 3, 4 and 5 respectively. In each context, the dissertation considers severability, applicable law, and the formal and essential validity of choice of court agreements, and explores the situation when there is a breach of the choice of court agreement. The 2005 Hague Convention is a great international effort to establish harmonized jurisdiction rules on choice of court agreements. Article 25 of Brussels I
Recast is a good regional example for regulating choice of court agreements within the EU. Chinese law and judicial practices also increasingly respect choice of court agreements between the parties. As the UK and the EU are negotiating Brexit and China signed the 2005 Hague Convention but has not ratified it yet, finally, in Chapter 6, this dissertation not only examines the relationship between the 2005 Hague Convention and Brussels I Recast in terms of the UK, but also reviews the relationship between Chinese law and the 2005 Hague Convention. More importantly, this dissertation recommends some law reform measures for the future of Chinese law, which would seek to enhance the enforcement of choice of court agreements in the Chinese legal system
Pancreatic Mass with an Unusual Pathology: A Case Report
Intra-abdominal abscesses formation in patients
with no preceding symptoms is rare. Infection of the pancreas
occurs in 5–9% of patients with acute pancreatitis, more commonly
as a complication of necrotising or severe pancreatitis. We have
reported a case of a 64-year-old almost entirely asymptomatic man
who underwent a Whipple's procedure following extensive
investigation of a pancreatic mass. The pathology and histology
showed no evidence of malignancy, and instead a true pancreatic
abscess, centred around an impacted cholesterol calculus in the
distal CBD. Of suspicious pancreatic masses that are resected,
chronic choledocholithiasis is the aetiology in less than 5% of nonmalignant or “false positives.” This report describes such a
case
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