We develop a theoretical analysis of the performance of the regularized least-square algorithm on a reproducing kernel Hilbert space in the supervised learning setting. The presented results hold in ...the general framework of vector-valued functions; therefore they can be applied to multitask problems. In particular, we observe that the concept of effective dimension plays a central role in the definition of a criterion for the choice of the regularization parameter as a function of the number of samples. Moreover, a complete minimax analysis of the problem is described, showing that the convergence rates obtained by regularized least-squares estimators are indeed optimal over a suitable class of priors defined by the considered kernel. Finally, we give an improved lower rate result describing worst asymptotic behavior on individual probability measures rather than over classes of priors. PUBLICATION ABSTRACT
Uno studio retrospettivo è stato condotto su 31 pazienti, giunti all’osservazione della cinica ORL Audiologia e Foniatria dell’Università di Pisa dal 2007 al 2013, affetti da ipoacusia ...neurosensoriale improvvisa, fluttuante o progressiva nell’unico orecchio udente. L’intero gruppo di pazienti è stato valutato con una adeguata anamnesi, otomicroscopia, esami di imaging (TC RMN), test audiologici (audiometria tonale e vocale, impedenziometria, potenziali evocati uditivi e otoemissioni acustiche). Questo gruppo di pazienti è stato sottoposto anche a una valutazione genetica (ricerca mutazioni CX 26, CX 30 e DNA mitocondriale A1555G) e a test di laboratorio. I pazienti con ipoacusia improvvisa o rapidamente progressiva sono stati trattati con diuretici osmotici e corticosteroidi (endovena o intratimpanici). I pazienti che non hanno recuperato in maniera adeguata dopo il trattamento sono stati avviati a un percorso di protesizzazione. Nei pazienti con insufficiente resa protesica sono stati sottoposti ad impianto cocleare. Lo scopo di questo studio è quello di discutere l’epidemiologia, l’eziopatogenesi e le caratteristiche cliniche di pazienti affetti da ipoacusia neurosensoriale nell’unico orecchio udente e inoltre discutere le indicazioni e la scelta dell’orecchio da impiantare in questa categoria di pazienti.
We discuss how a large class of regularization methods, collectively known as spectral regularization and originally designed for solving ill-posed inverse problems, gives rise to regularized ...learning algorithms. All of these algorithms are consistent kernel methods that can be easily implemented. The intuition behind their derivation is that the same principle allowing for the numerical stabilization of a matrix inversion problem is crucial to avoid overfitting. The various methods have a common derivation but different computational and theoretical properties. We describe examples of such algorithms, analyze their classification performance on several data sets and discuss their applicability to real-world problems.
The regularization parameter choice is a fundamental problem in Learning Theory since the performance of most supervised algorithms crucially depends on the choice of one or more of such parameters. ...In particular a main theoretical issue regards the amount of prior knowledge needed to choose the regularization parameter in order to obtain good learning rates. In this paper we present a parameter choice strategy, called the balancing principle, to choose the regularization parameter without knowledge of the regularity of the target function. Such a choice adaptively achieves the best error rate. Our main result applies to regularization algorithms in reproducing kernel Hilbert space with the square loss, though we also study how a similar principle can be used in other situations. As a straightforward corollary we can immediately derive adaptive parameter choices for various kernel methods recently studied. Numerical experiments with the proposed parameter choice rules are also presented.
•Hypercapnia in Pompe disease can be caused by blunted respiratory drive.•This new phenotype may have therapeutic implications.•Enzyme therapy might affect differently patients with blunted ...respiratory drive.
Subjects with late-onset Pompe disease (LOPD) typically present as slowly progressive proximal muscle weakness. Respiratory muscle weakness and diaphragmatic paralysis are common features, and may be the initial manifestation of the disease. There is often a poor correlation between the severity of limb and respiratory muscle weakness. Early clinical observations about disproportionate hypercapnia to the respiratory muscular weakness in late-onset Pompe disease were recognized and will be discussed with special reference to blunted respiratory drive, and the connections between early clinical observations, respiratory functional studies and anatomical findings. According to new evidence about blunted respiratory drive in Pompe disease, it is necessary to rethink what is meant by “asymptomatic Pompe disease” and propose a new phenotype with its therapeutic implications. The conceptual model of the mechanisms leading to respiratory failure in this disease could be considered according to these new findings. It may broaden the diagnostic spectrum of the adult forms and warrants a closer interaction between neurologists and pulmonologists. The recognition of this new phenotype of predominant central alveolar hypoventilation in Pompe disease will improve the understanding of the underlying mechanisms of ventilatory failure and could lead to improved future therapeutic strategies.
A new, simple, and selective method for preconcentration and determination of Cr(VI) in aqueous samples. After adsorption in “batch mode” on Aliquat 336-AC, determinations were made directly on the ...solid by X-ray fluorescence spectrometry, which had the advantage of not requiring the step of elution of the chromium retained. The enrichment factor was calculated considering that the tablets obtained from 10 mL solution of Cr(VI) (1000 μg L⁻¹) had a final thickness of 0.64 mm and a diameter of 16.7 mm; the volume deposited on the pellet was 0.14 cm³. The preconcentration factor obtained was 71-fold, which was highly satisfactory for chromium trace analysis by XRF. Finally, the method was successfully applied to the determination of Cr(VI) in drinking water samples. graphic removed
The catalytic growth of carbon nanotubes is performed at 580
°C with iron catalyst using a hot-wall CVD technique. It is shown that the growth mode can be switched from ‘tip’ to ‘base’ growth mode by ...an insertion of plasma pre-treatment of catalyst at room temperature before growth. To understand this phenomenon, the oxidation state of catalyst is compared using XPS before and after the pre-treatment. Growth mechanisms induced by different oxidation states of catalyst are proposed to explain the switching of the growth mode. A thermodynamic calculation shows the relation between induced growth mode and resulting CNT diameter.
•Glycerol did not modify ruminal fatty acid composition when incubated with oils.•Proportion of Anaerovibrio lipolytica increased in all diets with glycerol.•Glycerol was ineffective to reduce ...negative effects of oils on fermentation.•Glycerol combined with soybean oil decreased methane production.
Three runs of in vitro incubations were conducted to evaluate the effect of glycerol (0 or 150g/kg DM) combined with three different diets: Tifton 85 hay at 850g/kg DM without oil seeds (HWO), Tifton 85 hay+80g of soybean oil/kg DM (HSO) and Tifton 85 hay+80g of linseed oil/kg DM (HLO) incubated for 0, 6, 12 and 24h on fatty acid composition and ruminal fermentation parameters. Real-time PCR was used to quantify microbial population at 24h. Methanogens, fibrolitic and lipolityc bacteria were expressed as a proportion of total rumen bacterial 16S rDNA. Separately, kinetic of gas production was assessed at 2, 4, 6, 8, 10, 12, 14, 18, 22, 24, 36, 42 and 48h. In vitro true digestibility, g/kg (IVTD) and CH4 (%/g DMD) production were evaluated at 48h. The experimental design for fatty acid composition and ruminal parameters was a randomized block in a factorial arrangement 2×3×4, glycerol, diets and time, respectively. Microbial quantification, IVTD and methane were evaluated with the same design but without time as a factor. The pH value and ammonia concentration were lower in HWO compared with HSO and HLO diets, independent of glycerol addition. Ruminococcus albus, Ruminococcus flavefaciens, Butyrivrio vaccenic acid and stearic acid subgroup did not change with glycerol and oil addition (P>0.05). Among all cellulolytic bacteria, Fibrobacter succinogenes was the most sensitive to the addition of vegetable oil in the diet. Methane production decreased in HSO diet combined with glycerol and HLO diets with or without glycerol addition. Lag time (h) from the gas production kinetics decreased in HWO and HSO diets combined with glycerol. The C2:C3 ratio decreased in diets with glycerol addition. Glycerol inclusion did not reduce biohydrogenation of unsaturated fatty acids in vitro. Glycerol was ineffective to reduce the potentially negative effects of vegetable oils on ruminal fermentation and digestibility in vitro. Indeed, the proportion of Anaerovibrio lipolytica increased in all diets with glycerol added and unsaturated fatty acids profile remained unchanged.
In this article, we present an innovative approach for congenital hypothyroidism (CHT) screening. This pathology is the most common preventable cause of mental retardation, affecting newborns around ...the world. Its consequences could be avoided with an early diagnosis through the thyrotropin (TSH) level measurement. To accomplish the determination of TSH, synthesized zinc oxide (ZnO) nanobeads (NBs) covered by chitosan (CH), ZnO-CH NBs, were covalently attached to the central channel of the designed microfluidic device. These beads were employed as platform for anti-TSH monoclonal antibody immobilization to specifically recognize and capture TSH in neonatal samples without any special pretreatment. Afterwards, the amount of this trapped hormone was quantified by horseradish peroxidase (HRP)-conjugated anti-TSH antibody. HRP reacted with its enzymatic substrate in a redox process, which resulted in the appearance of a current whose magnitude was directly proportional to the level of TSH in the neonatal sample. The structure and morphology of synthesized ZnO-CH NBs were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The calculated detection limits for electrochemical detection and the enzyme-linked immunosorbent assay procedure were 0.00087 μUI mL
−1
and 0.015 μUI mL
−1
, respectively, and the within- and between-assay coefficients of variation were below 6.31 % for the proposed method. According to the cut-off value for TSH neonatal screening, a reasonably good limit of detection was achieved. These above-mentioned features make the system advantageous for routine clinical analysis adaptation.
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