13,903 research outputs found
RETINAL ANGIOMATOUS PROLIFERATION: A Quantitative Analysis of the Fundoscopic Features of the Fellow Eye
PURPOSE:
To quantitatively analyze and compare the fundoscopic features between fellow eyes of retinal angiomatous proliferation and typical exudative age-related macular degeneration and to identify possible predictors of neovascularization.
METHODS:
Retrospective case-control study. Seventy-nine fellow eyes of unilateral retinal angiomatous proliferation (n = 40) and typical exudative age-related macular degeneration (n = 39) were included. Fundoscopic features of the fellow eyes were assessed using digital color fundus photographs taken at the time of diagnosis of neovascularization in the first affected eye. Grading was performed by two independent graders using RetmarkerAMD, a computer-assisted grading software based on the International Classification and Grading System for age-related macular degeneration.
RESULTS:
Baseline total number and area (square micrometers) of drusen in the central 1,000, 3,000, and 6,000 μm were considerably inferior in the fellow eyes of retinal angiomatous proliferation, with statistically significant differences (P 510,196 μm2 in the central 6,000 μm was associated with an increased risk of neovascularization (hazard ratio, 4.35; 95% confidence interval [1.56-12.15]; P = 0.005).
CONCLUSION:
Baseline fundoscopic features of the fellow eye differ significantly between retinal angiomatous proliferation and typical exudative age-related macular degeneration. A large area (>510,196 μm2) of soft drusen in the central 6,000 μm confers a significantly higher risk of neovascularization and should be considered as a phenotypic risk factor
Modelling the progression of treatment scenarios in the HIV/AIDS epidemic
Advances in recent treatments for HIV/AIDS patients have shown dramatic outcomes in extending the incubation period and AIDS survival time, whilst also providing significant improvements in the quality of patients' lives. This thesis establishes a model of the HIV/AIDS epidemic that incorporates the effects of treatments, in particular, the introduction of highly active antiretroviral therapy (HAART), which became widely available during 1996. The technique of compartmental modelling is employed in an attempt to reproduce observed AIDS incidence/prevalence, HIV incidence/prevalence, and deaths from AIDS data. There are movements between compartments (sub-populations affected by the HIV/AIDS epidemic) each with an associated parameter. Each sub-population has a differential-difference equation associated with it. Once these equations have been solved numerically they give a set of steady-state solutions, from which it is possible to estimate HIV/AIDS incidence and prevalence. Some parameter values within the model are obtained from surveys, census results, etc., but others are derived using a maximum likelihood estimation (MLE) procedure. The use of realistic values gives impressive results, creating a remarkable fit with routinely collected data relating to levels of HIV/AIDS incidence and prevalence in the UK homosexual population. Finally, the model is used to project levels of incidence and prevalence over the next few years, and to investigate several possible 'what-if' scenarios, with a brief investigation into the consequent cost implications.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
A comparison of the galaxy peculiar velocity field with the PSCz gravity field-- A Bayesian hyper-parameter method
We constructed a Bayesian hyper-parameter statistical method to quantify the
difference between predicted velocities derived from the observed galaxy
distribution in the \textit{IRAS}-PSC redshift survey and peculiar
velocities measured using different distance indicators. In our analysis we
find that the model--data comparison becomes unreliable beyond 70 \hmpc
because of the inadequate sampling by \textit{IRAS} survey of prominent,
distant superclusters, like the Shapley Concentration. On the other hand, the
analysis of the velocity residuals show that the PSC gravity field provides
an adequate model to the local, \le 70 \hmpc, peculiar velocity field. The
hyper-parameter combination of ENEAR, SN, A1SN and SFI++ catalogues in the
Bayesian framework constrains the amplitude of the linear flow to be
. For an rms density fluctuations in the PSC galaxy
number density , we obtain an estimate of the
growth rate of density fluctuations ,
which is in excellent agreement with independent estimates based on different
techniques.Comment: 14 pages, 32 figures, MNRAS in press, matched the MNRAS published
versio
Doctor, how much weight will I lose? - a new individualized predictive model for weight loss
Bariatric surgery is an effective treatment for weight loss, but the patient’s ability to reach a sustained weight loss depends upon several technical and individual factors. Creating an easy model that adapts bariatric surgery’s weight loss goals for each patient is very important for pre-surgery and follow-up evaluations.info:eu-repo/semantics/publishedVersio
A new method of measuring the cluster peculiar velocity power spectrum
We propose to use spatial correlations of the kinetic Sunyaev-Zeldovich (KSZ)
flux as an estimator of the peculiar velocity power spectrum. In contrast with
conventional techniques, our new method does not require measurements of the
thermal SZ signal or the X-ray temperature. Moreover, this method has the
special advantage that the expected systematic errors are always sub-dominant
to statistical errors on all scales and redshifts of interest. We show that
future large sky coverage KSZ surveys may allow a peculiar velocity power
spectrum estimates of an accuracy reaching ~10%.Comment: 5 pages, 2 figures, MNRAS in Press (doi:
10.1111/j.1365-2966.2008.13454.x
Automatic Network Fingerprinting through Single-Node Motifs
Complex networks have been characterised by their specific connectivity
patterns (network motifs), but their building blocks can also be identified and
described by node-motifs---a combination of local network features. One
technique to identify single node-motifs has been presented by Costa et al. (L.
D. F. Costa, F. A. Rodrigues, C. C. Hilgetag, and M. Kaiser, Europhys. Lett.,
87, 1, 2009). Here, we first suggest improvements to the method including how
its parameters can be determined automatically. Such automatic routines make
high-throughput studies of many networks feasible. Second, the new routines are
validated in different network-series. Third, we provide an example of how the
method can be used to analyse network time-series. In conclusion, we provide a
robust method for systematically discovering and classifying characteristic
nodes of a network. In contrast to classical motif analysis, our approach can
identify individual components (here: nodes) that are specific to a network.
Such special nodes, as hubs before, might be found to play critical roles in
real-world networks.Comment: 16 pages (4 figures) plus supporting information 8 pages (5 figures
Modality, Potentiality and Contradiction in Quantum Mechanics
In [11], Newton da Costa together with the author of this paper argued in
favor of the possibility to consider quantum superpositions in terms of a
paraconsistent approach. We claimed that, even though most interpretations of
quantum mechanics (QM) attempt to escape contradictions, there are many hints
that indicate it could be worth while to engage in a research of this kind.
Recently, Arenhart and Krause [1, 2, 3] have raised several arguments against
this approach and claimed that, taking into account the square of opposition,
quantum superpositions are better understood in terms of contrariety
propositions rather than contradictory propositions. In [17] we defended the
Paraconsistent Approach to Quantum Superpositions (PAQS) and provided arguments
in favor of its development. In the present paper we attempt to analyze the
meanings of modality, potentiality and contradiction in QM, and provide further
arguments of why the PAQS is better suited, than the Contrariety Approach to
Quantum Superpositions (CAQS) proposed by Arenhart and Krause, to face the
interpretational questions that quantum technology is forcing us to consider.Comment: Published in: New Directions in Paraconsistent Logic, J-Y B\'eziau M.
Chakraborty & S. Dutta (Eds.), Springer, in press. arXiv admin note: text
overlap with arXiv:1404.518
The metallicity gradient as a tracer of history and structure : the Magellanic Clouds and M33 galaxies
Original article can be found at: http://www.aanda.org/ Copyright The European Southern Observatory (ESO) DOI: 10.1051/0004-6361/200912138Context. The stellar metallicity and its gradient place constraints on the formation and evolution of galaxies. Aims. This is a study of the metallicity gradient of the LMC, SMC and M33 galaxies derived from their asymptotic giant branch (AGB) stars. Methods. The [Fe/H] abundance was derived from the ratio between C- and M-type AGB stars and its variation analysed as a function of galactocentric distance. Galaxy structure parameters were adopted from the literature. Results. The metallicity of the LMC decreases linearly as −0.047±0.003 dex kpc−1 out to ∼8 kpc from the centre. In the SMC, [Fe/H] has a constant value of ∼−1.25 ± 0.01 dex up to ∼12 kpc. The gradient of the M33 disc, until ∼9 kpc, is −0.078 ± 0.003 dex kpc−1 while the outer disc/halo, out to ∼25 kpc, has [Fe/H] ∼ −1.7 dex. Conclusions. The metallicity of the LMC, as traced by different populations, bears the signature of two major star forming episodes: the first one constituting a thick disc/halo population and the second one a thin disc and bar due to a close encounter with the Milky Way and SMC. The [Fe/H] of the recent episode supports an LMC origin for the Stream. The metallicity of the SMC supports star formation, ∼3 Gyr ago, as triggered by LMC interaction and sustained by the bar in the outer region of the galaxy. The SMC [Fe/H] agrees with the present-day abundance in the Bridge and shows no significant gradient. The metallicity of M33 supports an “insideout” disc formation via accretion of metal poor gas from the interstellar medium.Peer reviewe
Catalysts based on Co-Birnessite and Co-Todorokite for the efficient production of hydrogen by ethanol steam reforming
[EN] Two structured manganese oxides (Birnessite and Todorokite) containing Co have been studied in the steam reforming of ethanol. It has been found that both materials are active in the hydrogen production, exhibiting high values of conversion of ethanol and selectivities to hydrogen (100% and 70%, respectively). The best results have been obtained with the catalyst based on Todorokite material. Characterization by DRX, BET area, TPR and TEM has allowed to find that the excellent performance exhibited by this material could be attributed to the lower size of the Co metallic particles present in this sample (6 nm vs 12 nm in Birnessite). This lower size could be related to the especial microporous structure of Todorokite precursor, which could provide high-quality positions for the stabilization of the Co metal particles during calcination and reduction steps. Catalytic deactivation has also been considered. Deactivation was found higher for Todorokite-based catalyst, which presented the largest amount of deposited carbon (26.2 wt% for Co-TOD vs 10.6 wt% for Co-BIR). On the other hand, the degree of metal sintering was found similar in both catalysts. Therefore, the deactivation of the catalysts has been attributed primarily to the deposition of coke. The results presented here show that it is possible to prepare new catalysts based on manganese oxides with Birnessite and Todorokite structure and promoted with Co with high catalytic performance in the steam reforming of ethanol. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.The doctor Javier Francisco Da Costa Serra acknowledges the CSIC for granted the scholarship predoctoral-JAE-CSIC. Moreover, Electronic Microscopy Service of UPV for TEM images.Da Costa Serra, JF.; Chica, A. (2018). Catalysts based on Co-Birnessite and Co-Todorokite for the efficient production of hydrogen by ethanol steam reforming. International Journal of Hydrogen Energy. 43(35):16859-16865. https://doi.org/10.1016/j.ijhydene.2017.12.114S1685916865433
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