6,116 research outputs found
Relative entropy via non-sequential recursive pair substitutions
The entropy of an ergodic source is the limit of properly rescaled 1-block
entropies of sources obtained applying successive non-sequential recursive
pairs substitutions (see P. Grassberger 2002 ArXiv:physics/0207023 and D.
Benedetto, E. Caglioti and D. Gabrielli 2006 Jour. Stat. Mech. Theo. Exp. 09
doi:10.1088/1742.-5468/2006/09/P09011). In this paper we prove that the cross
entropy and the Kullback-Leibler divergence can be obtained in a similar way.Comment: 13 pages , 2 figure
Effects of blood transfusion on exercise capacity in thalassemia major patients
Anemia has an important role in exercise performance. However, the direct link between rapid changes of hemoglobin and exercise performance is still unknown.To find out more on this topic, we studied 18 beta-thalassemia major patients free of relevant cardiac dysfunction (age 33.5±7.2 years,males = 10). Patients performed a maximal cardiopulmolmonary exercise test (cycloergometer, personalized ramp protocol, breath-by-breath measurements of expired gases) before and the day after blood transfusion (500 cc of red cell concentrates). After blood transfusion, hemoglobin increased from 10.5±0.8 g/dL to 12.1±1.2 (p<0.001), peak VO2 from 1408 to 1546mL/min (p<0.05), and VO2 at anaerobic threshold from 965 to 1024mL/min (p<0.05). No major changes were observed as regards heart and respiratory rates either at peak exercise or at anaerobic threshold. Similarly, no relevant changes were observed in ventilation efficiency, as evaluated by the ventilation vs. carbon dioxide production relationship, or in O2 delivery to the periphery as analyzed by the VO2 vs. workload relationship. The relationship between hemoglobin and VO2 changes showed, for each g/dL of hemoglobin increase, a VO2 increase = 82.5 mL/min and 35 mL/min, at peak exercise and at anaerobic threshold, respectively. In beta-thalassemia major patients, an acute albeit partial anemia correction by blood transfusion determinates a relevant increase of exercise performance, observed both at peak exercise and at anaerobic threshold
Neural Mechanisms Underlying Paradoxical Performance for Monetary Incentives Are Driven by Loss Aversion
Employers often make payment contingent on
performance in order to motivate workers. We used
fMRI with a novel incentivized skill task to examine
the neural processes underlying behavioral responses
to performance-based pay. We found that
individuals’ performance increased with increasing
incentives; however, very high incentive levels led
to the paradoxical consequence of worse performance.
Between initial incentive presentation and
task execution, striatal activity rapidly switched
between activation and deactivation in response
to increasing incentives. Critically, decrements in
performance and striatal deactivations were directly
predicted by an independent measure of behavioral
loss aversion. These results suggest that incentives
associated with successful task performance are
initially encoded as a potential gain; however, when
actually performing a task, individuals encode the
potential loss that would arise from failure
Hide-and-Seek with Directional Sensing
We consider a game played between a hider, who hides a static object in one
of several possible positions in a bounded planar region, and a searcher, who
wishes to reach the object by querying sensors placed in the plane. The
searcher is a mobile agent, and whenever it physically visits a sensor, the
sensor returns a random direction, corresponding to a half-plane in which the
hidden object is located. We first present a novel search heuristic and
characterize bounds on the expected distance covered before reaching the
object. Next, we model this game as a large-dimensional zero-sum dynamic game
and we apply a recently introduced randomized sampling technique that provides
a probabilistic level of security to the hider. We observe that, when the
randomized sampling approach is only allowed to select a very small number of
samples, the cost of the heuristic is comparable to the security level provided
by the randomized procedure. However, as we allow the number of samples to
increase, the randomized procedure provides a higher probabilistic security
level.Comment: A short version of this paper (without proofs) will be presented at
the 18th IFAC World Congress (IFAC 2011), Milan (Italy), August 28-September
2, 201
Dispersal of larval and juvenile seabream: Implications for Mediterranean marine protected areas
In the marine context, information about dispersal is essential for the design of networks of marine protected areas (MPAs). Generally, most of the dispersal of demersal fishes is thought to be driven by the transport of eggs and larvae in currents, with the potential contribution of dispersal in later life stages relatively minimal.Using otolith chemistry analyses, we estimate dispersal patterns across a spatial scale of approximately 180. km at both propagule (i.e. eggs and larvae) and juvenile (i.e. between settlement and recruitment) stages of a Mediterranean coastal fishery species, the two-banded seabream Diplodus vulgaris. We detected three major natal sources of propagules replenishing local populations in the entire study area, suggesting that propagule dispersal distance extends to at least 90. km. For the juvenile stage, we detected dispersal of up to 165. km. Our work highlights the surprising and significant role of dispersal during the juvenile life stages as an important mechanism connecting populations. Such new insights are crucial for creating effective management strategies (e.g. MPAs and MPA networks) and to gain support from policymakers and stakeholders, highlighting that MPA benefits can extend well beyond MPA borders, and not only via dispersal of eggs and larvae, but also through movement by juveniles
Fundamental Limits of Low-Density Spreading NOMA with Fading
Spectral efficiency of low-density spreading non-orthogonal multiple access
channels in the presence of fading is derived for linear detection with
independent decoding as well as optimum decoding. The large system limit, where
both the number of users and number of signal dimensions grow with fixed ratio,
called load, is considered. In the case of optimum decoding, it is found that
low-density spreading underperforms dense spreading for all loads. Conversely,
linear detection is characterized by different behaviors in the underloaded vs.
overloaded regimes. In particular, it is shown that spectral efficiency changes
smoothly as load increases. However, in the overloaded regime, the spectral
efficiency of low- density spreading is higher than that of dense spreading
Real Options for risk analysis in estimating the capitalization rate
A suitable cap-rate is generally determined
through an analogical process in order to estimate the value of
any real estate through the capitalization of the incomes. The
analogy relates to the risk and duration of similar investments.
There are numerous methods to rationalize the valuation of the
cap-rate. Appraisals have a certain degree of uncertainty in all
these methods. This paper proposes a methodology which
removes any uncertainty when evaluating the cap-rate. This is
achieved through the combination of the formal logic of the
Ellwood’s model and the Real Options Analysis
Promotion of proliferation and metastasis of hepatocellular carcinoma by LncRNA00673 based on the targeted-regulation of notch signaling pathway
we read with great interest the paper by Dr. Chen et al1, recently published in European
Review for Medical and Pharmacological Sciences and titled ‘‘Promotion of proliferation and
metastasis of hepatocellular carcinoma by LncRNA00673 based on the targeted-regulation
of notch signaling pathway’’. Authors concluded that lncRNA00673 is highly expressed and
may be a potential target for the treatment of Hepatocellular Carcinoma (HCC). Moreover,
according to authors, it can promote the proliferation and metastasis of HCC by the regulation
of Notch signaling pathway. We congratulate the authors for their interesting work
Urban transport management and customer perceived quality: a case study in the metropolitan area of Cagliari, Italy
Liberalization processes and the threats posed by ever increasing competition have forced public transport
companies in Italy to pay a closer attention to their customers, so to enhance loyalty and demand for transport.
These customer-targeted strategies have been responsible for some significant changes of otherwise consolidated
practices, in an attempt to lure new transit riders and discourage potential competitors from entering local markets.
The present study describes the results of an on-board survey implemented within the Cagliari’s metropolitan area
and aimed at discovering the degree of perceived quality toward the offer of public transport managed by CTM
S.p.A, the local transport agency in charge for the planning and management of public mobility around the
Sardinian’ regional capital. The research focuses on the implementation of an Impact Score methodology which,
following the suggestions included in the Transit Cooperative Research Program Report n°47 (1999), assesses
the degree of perceived quality with reference to ten core attributes of the public transport. The survey results
show a substantial lack of structural problems and a high level of perceived quality, although some attributes need
to be addressed if CTM aims to preserve and strengthen the central role so far enjoyed
Blocking CD248 molecules in perivascular stromal cells of patients with systemic sclerosis strongly inhibits their differentiation toward myofibroblasts and proliferation: A new potential target for antifibrotic therapy
Background: Fibrosis may be considered the hallmark of systemic sclerosis (SSc), the end stage triggered by different pathological events. Transforming growth factor-β (TGF-β) and platelet-derived growth factor BB (PDGF-BB) are profibrotic molecules modulating myofibroblast differentiation and proliferation, respectively. There is evidence linking CD248 with these two molecules, both highly expressed in patients with SSc, and suggesting that CD248 may be a therapeutic target for several diseases. The aim of this work was to evaluate the expression of CD248 in SSc skin and its ability to modulate SSc fibrotic process. Methods: After ethical approval was obtained, skin biopsies were collected from 20 patients with SSc and 10 healthy control subjects (HC). CD248 expression was investigated in the skin, as well as in bone marrow mesenchymal stem cells (MSCs) treated with TGF-β or PDGF-BB, by immunofluorescence, qRT-PCR, and Western blotting. Finally, in SSc-MSCs, the CD248 gene was silenced by siRNA. Results: Increased expression of CD248 was found in endothelial cells and perivascular stromal cells of SSc skin. In SSc-MSCs, the levels of CD248 and α-smooth muscle actin expression were significantly higher than in HC-MSCs. In both SSc- and HC-MSCs, PDGF-BB induced increased expression of Ki-67 when compared with untreated cells but was unable to modulate CD248 levels. After CD248 silencing, both TGF-β and PDGF-BB signaling were inhibited in SSc-MSCs. Conclusions: CD248 overexpression may play an important role in the fibrotic process by modulating the molecular target, leading to perivascular cells differentiation toward myofibroblasts and interfering with its expression, and thus might open a new therapeutic strategy to inhibit myofibroblast generation during SSc
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