623 research outputs found
Maximal quadratic modules on *-rings
We generalize the notion of and results on maximal proper quadratic modules
from commutative unital rings to -rings and discuss the relation of this
generalization to recent developments in noncommutative real algebraic
geometry. The simplest example of a maximal proper quadratic module is the cone
of all positive semidefinite complex matrices of a fixed dimension. We show
that the support of a maximal proper quadratic module is the symmetric part of
a prime -ideal, that every maximal proper quadratic module in a
Noetherian -ring comes from a maximal proper quadratic module in a simple
artinian ring with involution and that maximal proper quadratic modules satisfy
an intersection theorem. As an application we obtain the following extension of
Schm\" udgen's Strict Positivstellensatz for the Weyl algebra: Let be an
element of the Weyl algebra which is not negative semidefinite
in the Schr\" odinger representation. It is shown that under some conditions
there exists an integer and elements such
that is a finite sum of hermitian squares. This
result is not a proper generalization however because we don't have the bound
.Comment: 11 page
A Survey of Satisfiability Modulo Theory
Satisfiability modulo theory (SMT) consists in testing the satisfiability of
first-order formulas over linear integer or real arithmetic, or other theories.
In this survey, we explain the combination of propositional satisfiability and
decision procedures for conjunctions known as DPLL(T), and the alternative
"natural domain" approaches. We also cover quantifiers, Craig interpolants,
polynomial arithmetic, and how SMT solvers are used in automated software
analysis.Comment: Computer Algebra in Scientific Computing, Sep 2016, Bucharest,
Romania. 201
Multicentre observational study of adherence to Sepsis Six guidelines in emergency general surgery
Background
Evidence-based interventions may reduce mortality in surgical patients. This study documented the prevalence of sepsis, adherence to guidelines in its management, and timing of source control in general surgical patients presenting as an emergency.
Methods
Patients aged 16 years or more presenting with emergency general surgery problems were identified over a 7-day period and then screened for sepsis compliance (using the Sepsis Six standards, devised for severe sepsis) and the timing of source control (whether radiological or surgical). Exploratory analyses examined associations between the mode (emergency department or general practitioner) and time of admission, adherence to the sepsis guidelines, and outcomes (complications or death within 30 days).
Results
Of a total of 5067 patients from 97 hospitals across the UK, 911 (18·0 per cent) fulfilled the criteria for sepsis, 165 (3·3 per cent) for severe sepsis and 24 (0·5 per cent) for septic shock. Timely delivery of all Sepsis Six guidelines for patients with severe sepsis was achieved in four patients. For patients with severe sepsis, 17·6–94·5 per cent of individual guidelines within the Sepsis Six were delivered. Oxygen was the criterion most likely to be missed, followed by blood cultures in all sepsis severity categories. Surgery for source control occurred a median of 19·8 (i.q.r. 10·0–35·4) h after diagnosis. Omission of Sepsis Six parameters did not appear to be associated with an increase in morbidity or mortality.
Conclusion
Although sepsis was common in general surgical patients presenting as an emergency, adherence to severe sepsis guidelines was incomplete in the majority. Despite this, no evidence of harm was apparent
Planning and Leveraging Event Portfolios: Towards a Holistic Theory
This conceptual paper seeks to advance the discourse on the leveraging and legacies of events by examining the planning, management, and leveraging of event portfolios. This examination shifts the common focus from analyzing single events towards multiple events and purposes that can enable cross-leveraging among different events in pursuit of attainment and magnification of specific ends. The following frameworks are proposed: (1) event portfolio planning and leveraging, and (2) analyzing events networks and inter-organizational linkages. These frameworks are intended to provide, at this infancy stage of event portfolios research, a solid ground for building theory on the management of different types and scales of events within the context of a portfolio aimed to obtain, optimize and sustain tourism, as well as broader community benefits
A symbol of carnival or menace? Sojourner perceptions of the St George Cross flag during the FIFA 2010 World Cup
Plastic buckling of a rectangular plate under edge thrusts
The fundamental equations for the plastic buckling of a rectangular plate under edge thrusts are developed on the basis of a new set of stress-strain relations for the behavior of a metal in the plastic range. These relations are derived for buckling from a state of uniform compression. The fundamental equation for the buckling of a simply compressed plate together with typical boundary conditions is then developed and the results are applied to calculating the buckling loads of a thin strip, a simply supported plate, and a cruciform section. Comparisons with the theories of Timoshenko and Ilyushin are made. Finally, an energy method is given which can be used for finding approximate values of the critical load
Keeping it liminal. The Mondiali Antirazzisti (Anti-racist World Cup) as a multifocal interaction ritual
© 2013 Taylor & Francis. This paper examines how social mixing and celebration of diversity can be enabled through sports festivals marked by their carnivalesque atmosphere. Our analysis draws on a longitudinal ethnographic study of the Mondiali Antirazzisti (Anti-racist World Cup), a non-competitive football tournament and intercultural festival featuring the yearly participation of hardcore football fans (ultras), migrant groups, third-sector associations and other informal groups. We consider how the multifocal ritual form of the event helps to create a liminal space in which discrimination and stereotypes can be temporarily challenged. The sources of collective effervescence are multiplied by placing sport games within a wider range of other leisure and cultural activities, thus promoting internal diversity and the inclusion of outsiders. Additionally, social boundaries are also blurred by not emphasising the competitive dimension of the sporting activities, making sporting categorisations more fluid, and breaking down the separation between protagonists and spectators. Nonetheless, considering the transient character of liminality, we also investigate problems and limitations implied by the pursuit of these objectives. It is concluded that, despite a certain degree of self-referentiality, the festival fosters the spreading of anti-discriminatory cultures by enhancing the participants’ reflexivity and feeding their commitment in generating spin-off activities in different local contexts
Russia’s Legal Transitions: Marxist Theory, Neoclassical Economics and the Rule of Law
We review the role of economic theory in shaping the process of legal change in Russia during the two transitions it experienced during the course of the twentieth century: the transition to a socialist economy organised along the lines of state ownership of the means of production in the 1920s, and the transition to a market economy which occurred after the fall of the Soviet Union in the 1990s. Despite differences in methodology and in policy implications, Marxist theory, dominant in the 1920s, and neoclassical economics, dominant in the 1990s, offered a similarly reductive account of law as subservient to wider economic forces. In both cases, the subordinate place accorded to law undermined the transition process. Although path dependence and history are frequently invoked to explain the limited development of the rule of law in Russia during the 1990s, policy choices driven by a deterministic conception of law and economics also played a role.This is the author accepted manuscript. The final version is available from Springer via http://dx.doi.org/10.1007/s40803-015-0012-
Paricalcitol reduces oxidative stress and inflammation in hemodialysis patients
Background: Treatment with selective vitamin D receptor activators such as paricalcitol have been shown to exert
an anti-inflammatory effect in patients on hemodialysis, in addition to their action on mineral metabolism and
independently of parathyroid hormone (PTH) levels. The objective of this study was to evaluate the additional
antioxidant capacity of paricalcitol in a clinical setting.
Methods: The study included 19 patients with renal disease on hemodialysis, of whom peripheral blood was
obtained for analysis at baseline and three months after starting intravenous paricalcitol treatment. The following
oxidizing and inflammatory markers were quantified: malondialdehyde (MDA), nitrites and carbonyl groups,
indoleamine 2,3-dioxygenase (IDO), tumor necrosis factor alfa (TNF-α), interleukin-6 (IL-6), interleukin-18 (IL-18) and
C-reactive protein (CRP). Of the antioxidants and anti-inflammatory markers, superoxide dismutase (SOD), catalase,
reduced glutathione (GSH), thioredoxin, and interleukin-10 (IL-10) levels were obtained.
Results: Baseline levels of oxidation markers MDA, nitric oxide and protein carbonyl groups significantly decreased
after three months on paricalcitol treatment, while levels of GSH, thioredoxin, catalase and SOD activity significantly
increased. After paricalcitol treatment, levels of the inflammatory markers CRP, TNF-α, IL-6 and IL-18 were
significantly reduced in serum and the level of anti-inflammatory cytokine IL-10 was increased.
Conclusions: In renal patients undergoing hemodialysis, paricalcitol treatment significantly reduces oxidative stress
and inflammation, two well known factors leading to cardiovascular damageBackground: Treatment with selective vitamin D receptor activators such as paricalcitol have been shown to exert an anti-inflammatory effect in patients on hemodialysis, in addition to their action on mineral metabolism and independently of parathyroid hormone (PTH) levels. The objective of this study was to evaluate the additional antioxidant capacity of paricalcitol in a clinical setting.
Methods: The study included 19 patients with renal disease on hemodialysis, of whom peripheral blood was obtained for analysis at baseline and three months after starting intravenous paricalcitol treatment. The following oxidizing and inflammatory markers were quantified: malondialdehyde (MDA), nitrites and carbonyl groups, indoleamine 2,3-dioxygenase (IDO), tumor necrosis factor alfa (TNF-α), interleukin-6 (IL-6), interleukin-18 (IL-18) and C-reactive protein (CRP). Of the antioxidants and anti-inflammatory markers, superoxide dismutase (SOD), catalase,
reduced glutathione (GSH), thioredoxin, and interleukin-10 (IL-10) levels were obtained.
Results: Baseline levels of oxidation markers MDA, nitric oxide and protein carbonyl groups significantly decreased after three months on paricalcitol treatment, while levels of GSH, thioredoxin, catalase and SOD activity significantly increased. After paricalcitol treatment, levels of the inflammatory markers CRP, TNF-α, IL-6 and IL-18 were significantly reduced in serum and the level of anti-inflammatory cytokine IL-10 was increased.
Conclusions: In renal patients undergoing hemodialysis, paricalcitol treatment significantly reduces oxidative stress and inflammation, two well known factors leading to cardiovascular damage
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