32 research outputs found
Kinetics of Radioiodinated Heptadecanoic Acid and Metabolites in the Normal and Ischaemic Canine Heart
This study was undertaken to elucidate if the myocardial elimination rate of the radioactivity after administration of radioiodinated heptadecanoic acid was related to beta-oxidation of the fatty acid or related to washout of free radioiodide. In samples of normal and ischaemic myocardium the distribution of the radioactivity over free radioiodide, heptadecanoic acid and lipids was determined. In normal myocardium the major component was free radioiodide, only a small percentage being heptadecanoic acid. In ischaemic myocardium more radiolabelled lipids were present and less free iodide when compared with normal myocardium. The percentage heptadecanoic acid was slightly increased. It is concluded that radioiodinated heptadecanoic acid behaves like the natural analogues regarding uptake and distribution. However, washout of free radioiodide determines the elimination rate as observed during a scintigraphic stud
Interplay among critical temperature, hole content, and pressure in the cuprate superconductors
Within a BCS-type mean-field approach to the extended Hubbard model, a
nontrivial dependence of T_c on the hole content per unit CuO_2 is recovered,
in good agreement with the celebrated non-monotonic universal behaviour at
normal pressure. Evaluation of T_c at higher pressures is then made possible by
the introduction of an explicit dependence of the tight-binding band and of the
carrier concentration on pressure P. Comparison with the known experimental
data for underdoped Bi2212 allows to single out an `intrinsic' contribution to
d T_c / d P from that due to the carrier concentration, and provides a
remarkable estimate of the dependence of the inter-site coupling strength on
the lattice scale.Comment: REVTeX 8 pages, including 5 embedded PostScript figures; other
required macros included; to be published in Phys. Rev. B (vol. 54
High Fat Diet Increases Circulating Endocannabinoids Accompanied by Increased Synthesis Enzymes in Adipose Tissue
The endocannabinoid system (ECS) controls energy balance by regulating both energy intake and energy expenditure. Endocannabinoid levels are elevated in obesity suggesting a potential causal relationship. This study aimed to elucidate the rate of dysregulation of the ECS, and the metabolic organs involved, in diet-induced obesity. Eight groups of age-matched male C57Bl/6J mice were randomized to receive a chow diet (control) or receive a high fat diet (HFD, 45% of calories derived from fat) ranging from 1 day up to 18 weeks before euthanasia. Plasma levels of the endocannabinoids 2-arachidonoylglycerol (2-AG) and anandamide (N-arachidonoylethanolamine, AEA), and related N-acylethanolamines, were quantified by UPLC-MS/MS and gene expression of components of the ECS was determined in liver, muscle, white adipose tissue (WAT) and brown adipose tissue (BAT) during the course of diet-induced obesity development. HFD feeding gradually increased 2-AG (+132% within 4 weeks, P < 0.05), accompanied by upregulated expression of its synthesizing enzymes DaglĪ± and Ī² in WAT and BAT. HFD also rapidly increased AEA (+81% within 1 week, P < 0.01), accompanied by increased expression of its synthesizing enzyme Nape-pld, specifically in BAT. Interestingly, Nape-pld expression in BAT correlated with plasma AEA levels (R2 = 0.171, Ī² = 0.276, P < 0.001). We conclude that a HFD rapidly activates adipose tissue depots to increase the synthesis pathways of endocannabinoids that may aggravate the development of HFD-induced obesity
Using the Autism-Spectrum Quotient to Discriminate Autism Spectrum Disorder from ADHD in Adult Patients With and Without Comorbid Substance Use Disorder
It is unknown whether the Autism-spectrum quotient (AQ) can discriminate between Autism Spectrum Disorder (ASD) and Attention Deficit and Hyperactivity Disorder (ADHD) with or without comorbid Substance Use Disorder (SUD). ANOVAās were used to analyse the mean AQ (sub)scores of 129 adults with ASD or ADHD. We applied receiver operating characteristic (ROC) computations to assess discriminant power. All but one of the mean AQ (sub)scores were significantly higher for adults with ASD compared to those with ADHD. The SUD status in general was not significantly associated with AQ (sub)scores. On the Social Skills subscale patients with ASD and comorbid SUD showed less impairment than those without SUD. The cut-off score 26 yielded 73% correct classifications. The clinical use of the AQ in differentiating between ASD and ADHD is limited
Note on the approximation of distribution on Z+ by mixtures of negative binomial distributions Note on the approximation of distributions on Z Z + by mixtures of negative binomial distributions
Abstract It is shown that the distributions on Z Z + that can be approximated by mixtures of negative binomial distributions, are precisely the so-called Poisson mixtures, i.e., mixtures of Poisson distributions
A Decision Support System for Integrated Airport Performance Assessment and Capacity Management
Notwithstanding the global economic crisis, long-term forecasts of air transport growth
speak about a doubling in air transport demand in Europe by 2030 (Eurocontrol, 2008).
Characteristically, although the planned capacity of 138 Eurocontrol Statistical Reference
Area (ESRA) airports is planned to increase by 41% in total by 2030, the demand will still
exceed capacity of the airport system by as many as 7.0 million flights in a high-growth
scenario
for 2030 (Eurocontrol, 2008). Under such a scenario, 14\u201339 European airports will
need to operate at full capacity 8 h per day to accommodate only a part of the demand, similar
to what most severely congested airports do now (Eurocontrol, 2008). A direct consequence
of the mismatch between capacity and traffic growth is the increase of congestion and delays
both in the air and on the ground (at airports). Airports constitute the terminal nodes of
a continuously
expanding air transport network that should both efficiently and safely
accommodate
growing traffic.
The anticipated traffic growth in decades to come will again push capacity to the limit, thus
triggering unprecedented levels of congestion with far reaching impact on the environment
and the safety of operations. The latter concerns will pose serious challenges towards close
airport performance monitoring and improvement. Airport decision makers should be able
to cope with multiple \u2013 even conflicting \u2013 objectives and priorities assigned by various
stakeholders
regarding the multifaceted performance of the airport system such as the level
of service offered to the travelling public, the efficiency of airport and air traffic management
(ATM) operations, the quality of the surrounding environment, and the safety of the entire air
transport system. The assessment of the airport performance requires a deep understanding
of the manifold aspects of airport performance supported by advanced modelling capabilities
and decision support systems, or tools for measuring it. Such decision aids should be diverse
in that they should: (1) capture the behaviour of various entities (e.g. aircraft, passenger,
baggage)
processed through the system, (2) address different airport elements simultaneously
(e.g. runway system, taxiway system, apron area, terminal), and (3) consider a large set of
airport performance measures like capacity, delays, safety, security, noise and costs.
In order to deal with the multi-faceted aspects of the airport decision making process, a
wealth of decision support models and tools have appeared in both literature and practice
(Odoni, 1991; Tosic, 1992; Odoni et al., 1997; Lucic et al., 2007; Correia et al., 2008; Long
et al., 2009). Early modelling efforts developed rather focused applications (e.g. models, tools)
both in terms of integration scope and degree of coverage. They basically constituted \u2018monolithic\u2019
modelling structures exhibiting either analytical or simulation modelling approaches
with focused decision support capabilities mainly with view to a single airport performance
measure, for example, runway capacity (not accounting for trade-offs). At the same time, early
modelling efforts had a targeted/narrow coverage of specific elements of either airside (mainly
runways) or landside. Since their early stages of development in the 1960s, airport performance
models and tools have evolved substantially with a common orientation
being the pursuit of
more integration and expanded coverage capabilities. More recent research initiatives since
1990s attempted the integration of pre-selected and pre-existing
tool configurations in order to
model and evaluate simultaneously airport airside and landside and assess their interdependencies
(Andreatta et al., 1999; Zografos and Madas, 2006). These efforts primarily suffered
from the lack of a harmonized, fully integrated and automated computing environment needed
to execute the various models, as well as limited trade-off analysis capabilities.
Despite the rich experience in both models and tools for airport performance assessment,
modelling capabilities until 10 years ago or so addressed only partial aspects of the airport
performance and exhibited several deficiencies: (1) they were concerned with specific flows
or entities (e.g. aircraft, passengers, baggage), (2) they focused on specific airport elements
(e.g. runway system, apron, terminal), (3) they considered one (or very few) airport performance
indicator at a time (e.g. capacity, noise, safety, emissions), and (4) they were tailored for a
specific level of decision making, either strategic, tactical or operational. At the outset, there
was a clear lack of integrated modelling capabilities for assessing multiple performance
measures
simultaneously (and their trade-offs) for the airport system in its entirety (i.e. \u2018total
airport\u2019), that is, for both airport airside and landside simultaneously.
The latest developments in the airport modelling landscape involve the emergence of integrated
platforms or systems1. Currently, there are a limited number of software products/decision support
systems (mainly \u2018off-the-shelf\u2019) with integrated impact analysis capabilities for total airport
operations.
Most of them are purely simulation platforms basically integrating detailed simulation tools at a microscopic level. As a result, they do not exhibit macroscopic/aggregate analysis
capabilities
at the strategic decision making level with the use of analytical models. Furthermore,
the existing, simulation based tools are quite complicated, rather data intensive, have a costly set
up process for different airports, and require substantial tool familiarity
and prior computational
expertise. Another common feature for most of these tools is that they capture the airside-landside
interaction, but still provide limited trade-off analysis capabilities, since they primarily focus
on capacity and delay metrics. As a result, the basic modelling challenge remains, that is, to
develop systems and tools that will not only capture the manifold aspects of airport performance
in isolation, but will be also able to analyse, with reasonable effort, the various trade-offs and
interdependencies among these performance measures, entities, or airport elements.
In response to the identified modelling needs, an integrated Decision Support System (DSS),
the \u2018Supporting Platform for Airport Decision Making and Efficiency Analysis\u2019 (SPADE DSS),
has been developed recently. The proposed system has the form of a computational platform that
seamlessly integrates a variety of existing analytical models and simulation
tools in order to
capture the interdependencies among various measures of airport effectiveness (e.g. capacity,
delays, level of service, noise, safety, costs and benefits) and enable performance trade-off
analyses at various levels of detail (e.g. strategic, tactical/operational).
Furthermore, the SPADE
DSS allows decision makers and analysts to evaluate the efficiency of the entire airport complex
simultaneously (including also interaction effects among airport elements). However, the most
important and innovative element of the proposed
modelling approach is the adoption of the \u2018use
case\u2019 paradigm as the main building component
of the system implementation structure. The use
case driven implementation approach supports a problem or decision oriented approach that is
capable of addressing airport planning decisions in a user-friendly manner and at a reasonable
effort without requiring prior familiarity of the user with the selected tools (e.g. build
baseline/\u2018what-if\u2019 scenarios, prepare and exchange data sets, perform trade-off analysis).
The objective of this chapter is twofold:
1. to introduce the structure and constituting elements of the SPADE system; and
2. to demonstrate the decision support capabilities of the system under \u2018real-world\u2019 conditions by
means of two manifestations of the system for strategic decision making (Athens International
Airport) and operational/tactical decision making (Amsterdam Airport Schiphol).
The remainder of this chapter consists of four main sections. Section 2.2 provides an overall
description of the high level structure of the SPADE DSS with special emphasis placed on the
use case driven modelling concept. Section 2.3 provides a demonstration of two application
instances of the system for strategic and operational/tactical decision making, respectively.
Section 2.4 presents the concluding remarks and lessons learnt during the system implementation,
whilst reporting some brief results from the evaluation of the system. Finally, the final
sections present the acknowledgements and a list of reference sources
Kinetics of radioiodinated heptadecanoic acid and metabolites in the normal and ischaemic canine heart
This study was undertaken to elucidate if the myocardial elimination rate of the radioactivity after administration of radioiodinated heptadecanoic acid was related to beta-oxidation of the fatty acid or related to washout of free radioiodide. In samples of normal and ischaemic myocardium the distribution of the radioactivity over free radioiodide, heptadecanoic acid and lipids was determined. In normal myocardium the major component was free radioiodide, only a small percentage being heptadecanoic acid. In ischaemic myocardium more radiolabelled lipids were present and less free iodide when compared with normal myocardium. The percentage heptadecanoic acid was slightly increased. It is concluded that radioiodinated heptadecanoic acid behaves like the natural analogues regarding uptake and distribution. However, washout of free radioiodide determines the elimination rate as observed during a scintigraphic stud