1,247 research outputs found
Direct and Inverse Variational Problems on Time Scales: A Survey
We deal with direct and inverse problems of the calculus of variations on
arbitrary time scales. Firstly, using the Euler-Lagrange equation and the
strengthened Legendre condition, we give a general form for a variational
functional to attain a local minimum at a given point of the vector space.
Furthermore, we provide a necessary condition for a dynamic
integro-differential equation to be an Euler-Lagrange equation (Helmholtz's
problem of the calculus of variations on time scales). New and interesting
results for the discrete and quantum settings are obtained as particular cases.
Finally, we consider very general problems of the calculus of variations given
by the composition of a certain scalar function with delta and nabla integrals
of a vector valued field.Comment: This is a preprint of a paper whose final and definite form will be
published in the Springer Volume 'Modeling, Dynamics, Optimization and
Bioeconomics II', Edited by A. A. Pinto and D. Zilberman (Eds.), Springer
Proceedings in Mathematics & Statistics. Submitted 03/Sept/2014; Accepted,
after a revision, 19/Jan/201
Optimal planning of renewable energy-integrated electricity generation schemes with CO2 reduction target
This paper presents a Mixed Integer Linear Programming (MILP) model that was developed for the optimalplanning of electricitygenerationschemes for a nation to meet a specified CO2 emission target. The model was developed and implemented in General Algebraic Modeling System (GAMS) for the fleet of electricitygeneration in Peninsular Malaysia. In order to reduce the CO2 emissions by 50% from current CO2 emission level, the optimizer selected a scheme which includes Integrated Gasification Combined Cycle (IGCC), Natural Gas Combined Cycle (NGCC), nuclear and biomass from landfill gas and palm oil residues. It was predicted that Malaysia has potential to generate up to nine percent of electricity from renewableenergy (RE) based on the available sources of RE in Malaysia
On Arnold's 14 `exceptional' N=2 superconformal gauge theories
We study the four-dimensional superconformal N=2 gauge theories engineered by
the Type IIB superstring on Arnold's 14 exceptional unimodal singularities
(a.k.a. Arnold's strange duality list), thus extending the methods of 1006.3435
to singularities which are not the direct sum of minimal ones. In particular,
we compute their BPS spectra in several `strongly coupled' chambers.
From the TBA side, we construct ten new periodic Y-systems, providing
additional evidence for the existence of a periodic Y-system for each isolated
quasi-homogeneous singularity with (more generally, for each N=2
superconformal theory with a finite BPS chamber whose chiral primaries have
dimensions of the form N/l).Comment: 73 pages, 7 figure
Effect of fossil fuel price fluctuations on electricity planning comprising renewable energy
Electricity generation mix in Malaysia largely relies on fossil fuel including coal, natural gas (NG), diesel and fuel oil. In the Ninth Malaysia Plan, the government aims to achieve 5% electricity generation mix from renewable energy (RE). Nevertheless, until now, RE contributes less than 1% of the national electricity generation mix. In spite of its emission benefits, NG prices volatility have encouraged calls for investments in RE. Unfortunately, NG price in Malaysia is highly subsidized, thereby making RE implementation unattractive. This article addresses the impact of NG price (with and without subsidies) on RE-integrated electricity generation in Malaysia. The results show that a small increment in NG price will not affect the selection of RE source for electricity generation. If RE electricity generation is chosen, it will slightly increase the cost of electricity (COE) by 2.2 cents/kWh. Without NG subsidies, this cost can be translated to an additional 3 cents/kWh of CO
Breast MRI and tumour biology predict axillary lymph node response to neoadjuvant chemotherapy for breast cancer
The grinch who stole wisdom
Dr. Seuss is wise. How the Grinch Stole Christmas (Seuss, 1957) could serve as a parable for our time. It can also be seen as a roadmap for the development of contemplative wisdom. The abiding popularity of How the Grinch Stole Christmas additionally suggests that contemplative wisdom is more readily available to ordinary people, even children, than is normally thought. This matters because from the point of view of contemplatives in any of the world's philosophies or religions, people are confused about wisdom. The content of the nascent field of wisdom studies, they might say, is largely not wisdom at all but rather what it's like to live in a particular kind of prison cell, a well appointed cell perhaps, but not a place that makes possible either personal satisfaction or deep problem solving. I believe that what the contemplative traditions have to say is important; they offer a different orientation to what personal wisdom is, how to develop it, and how to use it in the world than is presently contained in either our popular culture or our sciences. In order to illustrate this I will examine, in some detail, one contemplative path within Buddhism. Buddhism is particularly useful in this respect because its practices are nontheistic and thus avoid many of the cultural landmines associated with the contemplative aspects of Western religions
Litigation after hip and knee replacement in the national health service
The results of hip and knee replacement surgery are generally regarded as positive for patients. Nonetheless, they are both major operations and have recognised complications. We present a review of relevant claims made to the National Health Service Litigation Authority. Between 1995 and 2010 there were 1004 claims to a value of £41.5 million following hip replacement surgery and 523 claims to a value of £21 million for knee replacement. The most common complaint after hip surgery was related to residual neurological deficit, whereas after knee replacement it was related to infection. Vascular complications resulted in the highest costs per case in each group.Although there has been a large increase in the number of operations performed, there has not been a corresponding relative increase in litigation. The reasons for litigation have remained largely unchanged over time after hip replacement. In the case of knee replacement, although there has been a reduction in claims for infection, there has been an increase in claims for technical errors. There has also been a rise in claims for non-specified dissatisfaction. This information is of value to surgeons and can be used to minimise the potential mismatch between patient expectation, informed consent and outcome
Neutrino-electron scattering in noncommutative space
Neutral particles can couple with the gauge field in the adjoint
representation at the tree level if the space-time coordinates are
noncommutative (NC). Considering neutrino-photon coupling in the NC QED
framework, we obtain the differential cross section of neutrino-electron
scattering. Similar to the magnetic moment effect, one of the NC terms is
proportional to , where is the electron recoil energy.
Therefore, this scattering provides a chance to achieve a stringent bound on
the NC scale in low energy by improving the sensitivity to the smaller electron
recoil energy.Comment: 12 pages, 2 figure
The Union of Hearts Depicted: Gladstone, Home Rule and United Ireland
First paragraph: William Ewart Gladstone detested political cartoons. They embodied caricature, the exaggeration of a particular feature into a deformity to excite ridicule or hatred. Cartoons, Gladstone once pointed out, had not existed in ancient Greece. There the ideal of human beauty was so deeply cherished that its distortion was not tolerated. Yet cartoons did the statesman powerful service during his long career. Their very frequency consolidated his image as a popular politician, bringing out qualities such as courage and tenacity that he was happy to have publicised. Nowhere, however, did they advance his cause more than in Ireland after the introduction of Home Rule. The nationalist journal United Ireland, as the illustrations in this paper will show, gave currency to striking depictions of Gladstone; and they vividly portrayed the union of hearts between England and Ireland that he preached so persistently in the late 1880s. The purpose of this article is to examine a sample of the cartoons, but first they need to be placed in their context
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