scholarly journals On toric geometry and K-stability of Fano varieties

2021 ◽  
Vol 8 (19) ◽  
pp. 548-577
Author(s):  
Anne-Sophie Kaloghiros ◽  
Andrea Petracci

We present some applications of the deformation theory of toric Fano varieties to K-(semi/poly)stability of Fano varieties. First, we present two examples of K-polystable toric Fano 3 3 -fold with obstructed deformations. In one case, the K-moduli spaces and stacks are reducible near the closed point associated to the toric Fano 3 3 -fold, while in the other they are non-reduced near the closed point associated to the toric Fano 3 3 -fold. Second, we study K-stability of the general members of two deformation families of smooth Fano 3 3 -folds by building degenerations to K-polystable toric Fano 3 3 -folds.

1999 ◽  
Vol 91 (1) ◽  
pp. 105-111 ◽  
Author(s):  
Kenji Ohata ◽  
Toshihiro Takami ◽  
Alaa El-Naggar ◽  
Michiharu Morino ◽  
Akimasa Nishio ◽  
...  

✓ The treatment of spinal intramedullary arteriovenous malformations (AVMs) with a diffuse-type nidus that contains a neural element poses different challenges compared with a glomus-type nidus. The surgical elimination of such lesions involves the risk of spinal cord ischemia that results from coagulation of the feeding artery that, at the same time, supplies cord parenchyma. However, based on evaluation of the risks involved in performing embolization, together with the frequent occurrence of reperfusion, which necessitates frequent reembolization, the authors consider surgery to be a one-stage solution to a disease that otherwise has a very poor prognosis. Magnetic resonance (MR) imaging revealed diffuse-type intramedullary AVMs in the cervical spinal cords of three patients who subsequently underwent surgery via the posterior approach. The AVM was supplied by the anterior spinal artery in one case and by both the anterior and posterior spinal arteries in the other two cases. In all three cases, a posterior median myelotomy was performed up to the vicinity of the anterior median fissure that divided the spinal cord together with the nidus, and the feeding artery was coagulated and severed at its origin from the anterior spinal artery. In the two cases in which the posterior spinal artery fed the AVM, the feeding artery was coagulated on the dorsal surface of the spinal cord. Neurological outcome improved in one patient and deteriorated slightly to mildly in the other two patients. Postoperative angiography demonstrated complete disappearance of the AVM in all cases. Because of the extremely poor prognosis of patients with spinal intramedullary AVMs, this surgical technique for the treatment of diffuse-type AVMs provides acceptable operative outcome. Surgical intervention should be considered when managing a patient with a diffuse-type intramedullary AVM in the cervical spinal cord.


2019 ◽  
Vol 11 (3) ◽  
pp. 328-341
Author(s):  
Rifki Ismal ◽  
Nurul Izzati Septiana

Purpose The demand for Saudi Arabian real (SAR) is very high in the pilgrimage (hajj) season while the authority, unfortunately, does not hedge the hajj funds. As such, the hajj funds are potentially exposed to exchange rate risk, which can impact the value of hajj funds and generate extra cost to the pilgrims. The purpose of this paper is to conduct simulations of Islamic hedging for pilgrimage funds to: mitigate and minimize exchange rate risk, identify and recommend the ideal time, amount and tenors of Islamic hedging for hajj funds, estimate cost saving by pursuing Islamic hedging and propose technical and general recommendations for the authority. Design/methodology/approach Forward transaction mechanism is adopted to compute Islamic forward between SAR and Rupiah (Indonesian currency) or IDR. Findings – based on simulations, the paper finds that: the longer the Islamic hedging tenors, the better is the result of Islamic hedging, the decreasing of IDR/USD is the right time to hedge the hajj funds and, on the other hand, the IDR/SAR appreciation is not the right time to hedge the hajj funds. Findings Based on simulations, the paper finds that: the longer the Islamic hedging tenors, the better is the result of Islamic hedging, the decreasing of IDR/USD is the right time to hedge the hajj funds and, on the other hand, the IDR/SAR appreciation is not the right time to hedge the hajj funds. Research limitations/implications The research suggests the authority to (and not to) hedge the hajj fund, depending on economic conditions and market indicators. Even though the assessment is for the Indonesian case, other countries maintaining hajj funds might also learn from this paper. Originality/value To the best of author’s knowledge, this is the first paper in Indonesia that attempts to simulate the optimal hedging of hajj funds.


Author(s):  
Lie Fu ◽  
Robert Laterveer ◽  
Charles Vial

AbstractGiven a smooth projective variety, a Chow–Künneth decomposition is called multiplicative if it is compatible with the intersection product. Following works of Beauville and Voisin, Shen and Vial conjectured that hyper-Kähler varieties admit a multiplicative Chow–Künneth decomposition. In this paper, based on the mysterious link between Fano varieties with cohomology of K3 type and hyper-Kähler varieties, we ask whether Fano varieties with cohomology of K3 type also admit a multiplicative Chow–Künneth decomposition, and provide evidence by establishing their existence for cubic fourfolds and Küchle fourfolds of type c7. The main input in the cubic hypersurface case is the Franchetta property for the square of the Fano variety of lines; this was established in our earlier work in the fourfold case and is generalized here to arbitrary dimension. On the other end of the spectrum, we also give evidence that varieties with ample canonical class and with cohomology of K3 type might admit a multiplicative Chow–Künneth decomposition, by establishing this for two families of Todorov surfaces.


1971 ◽  
Vol 34 (4) ◽  
pp. 537-543 ◽  
Author(s):  
Richard A. Lende ◽  
Wolff M. Kirsch ◽  
Ralph Druckman

✓ Cortical removals which included precentral and postcentral facial representations resulted in relief of facial pain in two patients. Because of known failures following only postcentral (SmI) ablations, these operations were designed to eliminate also the cutaneous afferent projection to the precentral gyrus (MsI) and the second somatic sensory area (SmII). In one case burning pain developed after a stroke involving the brain stem and was not improved by total fifth nerve section; prompt relief followed corticectomy and lasted until death from heart disease 20 months later. In the other case persistent steady pain that developed after fifth rhizotomy for trigeminal neuralgia proved refractory to frontal lobotomy; relief after corticectomy was immediate and has lasted 14 months. Cortical localization was established by stimulation under local anesthesia. Each removal extended up to the border of the arm representation and down to the upper border of the insula. Such a resection necessarily included SmII, and in one case responses presumably from SmII were obtained before removal. The suggestions of Biemond (1956) and Poggio and Mountcastle (1960) that SmII might be concerned with pain sensibility may be pertinent in these cases.


2021 ◽  
Vol 27 (4) ◽  
Author(s):  
Harold Blum ◽  
Daniel Halpern-Leistner ◽  
Yuchen Liu ◽  
Chenyang Xu
Keyword(s):  

2018 ◽  
Vol 13 (2) ◽  
pp. 179-190 ◽  
Author(s):  
T.M. Wong

Purpose The purpose of this paper is to identify the teaching innovations that have been implemented in higher education institutions in Asia and the perspectives of educators on them. Design/methodology/approach Semi-structured interviews were conducted with 28 educators who were affiliated with 23 higher education institutions in ten Asian countries/regions. The interviews covered information about the teaching innovations of the participants’ institutions, the characteristics of the innovative practices and the participants’ views on them. The relationships between the characteristics of institutions and their teaching innovations were also examined. Findings The results showed that the teaching innovations included two main categories, namely, those which involved the use of advanced technologies and those which did not. The innovations that involved the use of advanced technologies were mainly from larger institutions, while the other category was mainly from smaller ones and had been practised for less than 1.5 years. Differences were also identified between the two categories in terms of the aims and importance of innovations, innovative features, the evaluation of innovations and improvements needed for them. Originality/value The results highlighted that technology is only one of the many aspects of teaching innovations, which is different from the view prevailing in the literature. They also suggested that differences in the scale of institutions (in terms of number of students) possibly influences the kind of teaching innovations adopted.


2017 ◽  
Vol 21 (3) ◽  
pp. 208-223
Author(s):  
Byung Mun Lee

Purpose The purpose of this paper is to describe and analyze the rules on the formation of contracts under Korean law and the Contracts for the International Sale of Goods (CISG) in a comparative way and introduce the relevant proposed rules under the Amendment Draft of the Korean Civil Code (KCC). In addition, it attempts to compare and evaluate them in light of the discipline of comparative law. Design/methodology/approach In order to achieve the purposes of the study, it executes a comparative study of the rules as to the formation of contracts of the CISG, Korean law and the Amendment Draft of the KCC. The basic question for this comparative study is placed on whether a solution from one jurisdiction is more logical than the others and to what extent each jurisdiction has responded to protect the reasonable expectations of the parties in the rules as to the formation of contracts. Findings The comparative study finds that most of the rules under the CISG are quite plausible and logical and they are more or less well reflected in the proposals advanced by the KCC amendment committee. On the other hand, the other rules under the CISG which have brought criticisms in terms of their complexity and inconsistent case law invite us their revision or consistent interpretation. The drawbacks of the CISG have also been well responded in the Amendment Draft of the KCC. Nevertheless, it is quite unfortunate that the Amendment Draft of the KCC still has a rule that regards any purported performance with non-material alteration of the terms of an offer as an acceptance. Originality/value This study may provide legal and practical advice to both the seller and the buyer when they enter into a contract for international sales of goods. In addition, it may render us an insight into newly developed or developing rules in this area and show us how they interact with each other. Furthermore, it may be particularly useful in Korea where there is an ongoing discussion for revision of the KCC.


2016 ◽  
Vol 23 (5) ◽  
pp. 1111-1131 ◽  
Author(s):  
AbdulLateef Olanrewaju

Purpose – The opportunities that the emerging markets present to the players in the construction industry means that the players need to expand on the scope and size of their responsibilities and duties to the stakeholders. Each of the professionals now demands more specialised and sophisticated services from one another. The other players in the construction industry now require more emerging responsibilities and duties from the quantity surveyors. The purpose of this paper is to examine the roles that “modern” quantity surveyors play by measuring the gaps that exist in the services that the quantity surveyors provide. Design/methodology/approach – Primary data are collected through survey questionnaires. In total, 23 roles played by modern quantity surveyors are identified and addressed to the respondents to rank the rate at which quantity surveyors provide these “emerging” services. The collected data were analysed statistically. Findings – The results of the findings led to the conclusion that the quantity surveyors were not meeting the expectations of other players. Therefore, for competitiveness, quantity surveyors need to better meet demand expectations. Research limitations/implications – This findings of this research are constrained to the services or functions that the quantity provide in the construction industry. Practical implications – This knowledge is valuable to academic institutions that offer quantity surveying programmes, to practicing quantity surveyors, governments, and other players in the construction industry. It will allow quantity surveyors to reconcile supply and demand expectations. Originality/value – There is no known conclusive empirical study on services offered by quantity surveyors in any emerging markets. Therefore, the findings offer a fresh understanding on the services of quantity surveyors not only in Nigeria but elsewhere. While some of the services are common, others are peculiar to emerging markets.


Target ◽  
2017 ◽  
Vol 29 (2) ◽  
pp. 319-338 ◽  
Author(s):  
Teresa Iribarren

This article explores translational literary Web 2.0 practices and user-generated cultural creations on the Internet, focusing on video poetry that re-creates canonical poets’ bodies of work. It will be argued that the use of for-profit platforms like YouTube and Vimeo by indie creators and translators of video poetry favours the emergence of new translational attitudes, practices and objects that have positive but also contentious effects. One the one hand, these online mediators explore new poetic expressions and tend to make the most of the potential for dissemination of poetic heritage, providing visibility to non-hegemonic literatures. On the other hand, however, these translational digitally-born practices and creations by voluntary and subaltern mediators might reinforce the hegemonic position of large American Internet corporations at the risk of commodifying cultural capital, consolidating English as a lingua franca and perhaps, in the long run, even fostering a potentially monocultural and internationally homogeneous aesthetics.


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