185 research outputs found

    Multi-objective evolutionary fuzzy clustering for high-dimensional problems

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    This paper deals with the application of unsupervised fuzzy clustering to high dimensional data. Two problems are addressed: groups (clusters) number discovery and feature selection without performance losses. In particular we analyze the potential of a genetic fuzzy system, that is the integration of a multi-objective evolutionary algorithm with a fuzzy clustering algorithm. The main characteristic of the integrated approach is the ability to handle the two problems at the same time, suggesting a Pareto set of trade-off solutions which could have a better chance of matching the real needs. We exhibit the high quality clustering and features selection results by applying our approach to a real-world data set

    A Low-Power CMOS Bandgap Voltage Reference for Supply Voltages Down to 0.5 V

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    A voltage reference is strictly required for sensor interfaces that need to perform nonratiometric data acquisition. In this work, a voltage reference capable of working with supply voltages down to 0.5 V is presented. The voltage reference was based on a classic CMOS bandgap core, properly modified to be compatible with low-threshold or zero-threshold MOSFETs. The advantages of the proposed circuit are illustrated with theoretical analysis and supported by numerical simulations. The core was combined with a recently proposed switched capacitor, inverter-like integrator implementing offset cancellation and low-frequency noise reduction techniques. Experimental results performed on a prototype designed and fabricated using a commercial 0.18 μm CMOS process are presented. The prototype produces a reference voltage of 220 mV with a temperature sensitivity of 45 ppm/°C across a 10–50 °C temperature range. The proposed voltage reference can be used to source currents up to 100 μA with a quiescent current consumption of only 630 nA

    Thermal Noise-Boosting Effects in Hot-Wire-Based Micro Sensors

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    This article proposes an original approach aimed at modelling the noise density in sensors based on a single hot wire or pairs of thermally coupled wires. The model consists in an original combination of a previous electrothermal model of the wire with well-established assumptions on the thermal noise in conductors that carry moderate current densities. A simple method for estimating the model parameters with simple impedance spectroscopy is suggested. The predicted power spectral densities of the wire thermal noise differ from the result of previously presented analytical models, stimulating further experimental studies. The effects of the electrothermal feedback of both hot wires and hot-wire pairs on flicker noise is also intrinsically covered by the proposed approach

    Normal computed tomographic features and reference values for the coelomic cavity in pet parrots

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    BACKGROUND: The increasing popularity gained by pet birds over recent decades has highlighted the role of avian medicine and surgery in the global veterinary scenario; such a need for speciality avian medical practice reflects the rising expectation for high-standard diagnostic imaging procedures. The aim of this study is to provide an atlas of matched anatomical cross-sections and contrast-enhanced CT images of the coelomic cavity in three highly diffused psittacine species. RESULTS: Contrast-enhanced computed tomographic studies of the coelomic cavity were performed in 5 blue-and-gold macaws, 4 African grey parrots and 6 monk parakeets by means of a 4-multidetector-row CT scanner. Both pre- and post-contrast scans were acquired. Anatomical reference cross-sections were obtained from 5 blue-and-gold macaw, 7 African grey parrot, and 9 monk parakeet cadavers. The specimens were stored in a −20 °C freezer until completely frozen and then sliced at 5-mm intervals by means of a band saw. All the slices were photographed on both sides. Individual anatomical structures were identified by means of the available literature. Pre- and post-contrast attenuation reference values for the main coelomic organs are reported in Hounsfield units (HU). CONCLUSIONS: The results provide an atlas of matched anatomical cross-sections and contrast-enhanced CT images of the coelomic cavity in three highly diffused psittacine species

    Quantifying the Role of Homophily in Human Cooperation Using Multiplex Evolutionary Game Theory.

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    Nature shows as human beings live and grow inside social structures. This assumption allows us to explain and explore how it may shape most of our behaviours and choices, and why we are not just blindly driven by instincts: our decisions are based on more complex cognitive reasons, based on our connectedness on different spaces. Thus, human cooperation emerges from this complex nature of social network. Our paper, focusing on the evolutionary dynamics, is intended to explore how and why it happens, and what kind of impact is caused by homophily among people. We investigate the evolution of human cooperation using evolutionary game theory on multiplex. Multiplexity, as an extra dimension of analysis, allows us to unveil the hidden dynamics and observe non-trivial patterns within a population across network layers. More importantly, we find a striking role of homophily, as the higher the homophily between individuals, the quicker is the convergence towards cooperation in the social dilemma. The simulation results, conducted both macroscopically and microscopically across the network layers in the multiplex, show quantitatively the role of homophily in human cooperation

    Hospitalizations for tuberculosis in Sicily over the years 2009–2021: Clinical features, comorbidities, and predictors of mortality

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    Background: Very few data are available in the literature regarding tuberculosis (TB) hospitalization, and few studies have reported the clinical characteristics and comorbidities of admitted patients and burden and cost of hospitalization. In our study, we described the occurrence of TB hospital admissions in the southern Italian region of Sicily over 13 years (2009–2021), explored the characteristics of patients with TB, and determined the comorbidities associated with mortality. Method: Data on the hospital discharge of all patients with TB hospitalized in all Sicilian hospitals were retrospectively collected from hospital standard discharge forms. Age, sex, nationality, length of hospital stay, comorbidities, and TB localization were evaluated using univariate analysis according to in-hospital mortality. The factors associated with mortality were included in the logistic regression model. Results: In Sicily, 3745 people were hospitalized for TB, with 5239 admissions and 166 deaths from 2009 to 2021. Most hospitalizations involved Italian-born people (46.3%), followed by African-born people (32.8%) and Eastern European-born people (14.1%). The average hospitalization cost was EUR 5259 ± 2592, with a median length of stay of 16 days (interquartile range, 8–30) days. Multivariate analysis showed that the development of acute kidney failure (adjusted odds ratio [aOR]=7.2, p < 0.001), alcohol consumption (aOR=8.9, p = 0.001), malignant tumors (aOR=2.1, p = 0.022), human immunodeficiency virus infection (aOR=3.4, p < 0.001), sepsis (aOR=15.2, p < 0.001), central nervous system involvement (aOR=9.9, p < 0.001), and miliary TB (aOR=2.5, p = 0.004) were independent predictors of mortality. Conclusion: TB in Sicily remains an important cause of hospitalization. HIV infection and comorbidities may complicate patient management and worsen patient outcomes

    Serum low density lipoprotein subclasses in asthma

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    Background: The levels of serum low-density lipoproteins (LDL) have been implicated in the inflammatory cascade in a murine model of asthma. Recent findings suggest that LDL may modulate the inflammatory state of the asthmatic airways in humans. Objective: We explored whether LDL subclasses are associated with the occurrence and severity of asthma. Methods: 24 asthmatics (M/F: 11/13) and 24 healthy individuals, with normal BMI and absence of metabolic syndrome, matched for age and gender. Serum concentrations of LDL subclasses were distributed as seven bands (LDL-1 and -2 defined as large, least pro-inflammatory LDL, and LDL-3 to 7 defined as small, most pro-inflammatory LDL), using the LipoPrintª System (Quantimetrix Corporation, Redondo Beach, CA, USA). Results: LDL-1 was similar in the two groups (56 ± 16% vs. 53 ± 11, p = NS), while LDL-2 was significantly lower in asthmatics as compared to controls (35 ± 8% vs. 43 ± 10%, p = 0.0074). LDL-3 levels were two-fold higher in the asthmatics, but the difference did not reach the statistical significance (8± 7.3% vs. 4±3%, p=NS). Smaller subclasses LDL-4 to LDL-7 were undetectable in controls. In asthmatics, LDL-1 was positively associated with VC% predicted (r=+0.572, pZ0.0035) and FEV1% predicted (r=+0.492, p=+.0146). LDL-3 was inversely correlated with both VC% predicted (r =-0.535, p =0.0071) and FEV1% predicted (r =-0.465, p = 0.0222). Conclusions: The findings of this pilot study suggest a role of LDL in asthma, and advocate for larger studies to confirm the association between asthma and dyslipidemia

    CTLA-4 and PD-1 ligand gene expression in epithelial thyroid cancers

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    The dysregulation of PD-1 ligands (PD-L1 and PD-L2) and CTLA-4 ligands (CD80 and CD86) represents a tumor strategy to escape the immune surveillance. Here, the expression of PD-L1, PD-L2, CD80 and CD86 was evaluated at mRNA level in 94 patients affected by papillary thyroid carcinoma (PTC) and 11 patients affected by anaplastic thyroid carcinoma (ATC). Variations in the mRNAs in PTC patients were then correlated with clinicopathological features. The expression of all genes was deregulated in PTC and ATC tissues compared to normal tissues. In particular, the down-regulation of CD80 was observed in above all ATC. In addition, the increased expression of CD80 associated to longer disease-free survival in PTC. Higher expression of PD-L1 associated with the classical histological variant and with the presence of BRAFV600E mutation in PTC. The increased PD-L2 expression correlated with BRAFV600E mutation and lymph node metastasis, while its lower expression correlated with the follicular PTC variant. The latter was also associated with the CD80 down-regulation, which was also related to the absence of lymph node metastasis. In conclusion, we documented the overall dysregulation of PD-1 and CTLA-4 ligands in PTC and ATC tissues and a possible prognostic value for CD80 gene expression in PTC

    Risk Factors for Surgical Site Infection in Neonates: A Systematic Review of the Literature and Meta-Analysis

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    Purpose: Surgical site infections (SSI) contribute to postoperative morbidity and mortality in children. Our aim was to evaluate the prevalence and identify risk factors for SSI in neonates.Methods: Using a defined strategy, three investigators searched articles on neonatal SSI published since 2000. Studies on neonates and/or patients admitted to neonatal intensive care unit following cervical/thoracic/abdominal surgery were included. Risk factors were identified from comparative studies. Meta-analysis was conducted according to PRISMA guidelines using RevMan 5.3. Data are (mean ± SD) prevalence.Results: Systematic review—of 885 abstracts screened, 48 studies (27,760 neonates) were included. The incidence of SSI was 5.6% (1,564 patients). SSI was more frequent in males (61.8%), premature babies (77.4%), and following gastrointestinal surgery (95.4%). Meta-analysis—10 comparative studies (16,442 neonates; 946 SSI 5.7%) showed that predictive factors for SSI development were gestational age, birth weight, age at surgery, length of surgical procedure, number of procedure per patient, length of preoperative hospital stay, and preoperative sepsis. Conversely, preoperative antibiotic use was not significantly associated with development of SSI.Conclusions: Younger neonates and those undergoing abdominal procedures are at higher risk for SSI. Given the lack of evidence-based literature, prospective studies may help determine the risk factors for SSI in neonates
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