298 research outputs found

    Understanding Logical-Shift Error Propagation in Quanvolutional Neural Networks

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    Quanvolutional Neural Networks (QNNs) have been successful in image classification, exploiting inherent quantum capabilities to improve performance of the traditional convolution. Unfortunately, the qubit's reliability can be a significant issue for QNNs inference, since its logical state can be altered by both intrinsic noise and by the interaction with natural radiation. In this paper we aim at investigating the propagation of logical-shift errors (i.e. the unexpected modification of the qubit state) in QNNs. We propose a bottom-up evaluation reporting data from 13,322,547,200 logical-shift injections. We characterize the error propagation in the quantum circuit implementing a single convolution and then in various designs of the same QNN, varying the dataset and the network depth. We track the logical-shift error propagation through the qubits, channels, and subgrids identifying the faults that are more likely to cause misclassifications. We found that up to 10% of the injections in the quanvolutional layer cause misclassification and even logical-shifts of small magnitude can be sufficient to disturb the network functionality. Our detailed analysis shows that corruptions in the qubits' state that alter their probability amplitude are more critical than the ones altering their phase, that some object classes are more likely than others to be corrupted, that the criticality of subgrids depends on the dataset, and that the control qubits, once corrupted, are more likely to modify the QNN output than the target qubits

    Clinical Evidence: a useful tool for promoting evidence-based practice?

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    Background: Research has shown that many healthcare professionals have problems with guidelines as they would prefer to be given all relevent information relevent to decision-making rather than being told what they should do. This study assesses doctors' judgement of the validity, relevance, clarity and usability of the Italian translation of Clinical Evidence (CE) after its free distribution launched by the Italian Ministry of Health. Methods: Opinions elicited using a standardised questionnaire delivered either by mail or during educational or professional meetings. Results: Twenty percent (n = 1350) doctors participated the study. Most of them found CE's content valid, useful and relevant for their clinical practice, and said CE can foster communications among clinicians, particularly among GPs and specialists. Hospital doctors (63%) more often than GPs (48%) read the detailed presentation of individual chapters. Twenty-nine percent said CE brought changes in their clinical practice. Doctors appreciated CE's nature of an evidence-based information compendium and would have not preferred a collection of practice guidelines. Conclusions: Overall, the pilot initiative launched by the Italian Ministry of Health seems to have been well received and to support the subsequent decision to make the Italian edition of Clinical Evidence concise available to all doctors practising in the country. Local implementation initiatives should be warranted to favour doctor's use of CE

    Modeling of negative Poisson’s ratio (auxetic) crystalline cellulose Iβ

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    Energy minimizations for unstretched and stretched cellulose models using an all-atom empirical force field (Molecular Mechanics) have been performed to investigate the mechanism for auxetic (negative Poisson’s ratio) response in crystalline cellulose Iβ from kraft cooked Norway spruce. An initial investigation to identify an appropriate force field led to a study of the structure and elastic constants from models employing the CVFF force field. Negative values of on-axis Poisson’s ratios nu31 and nu13 in the x1-x3 plane containing the chain direction (x3) were realized in energy minimizations employing a stress perpendicular to the hydrogen-bonded cellobiose sheets to simulate swelling in this direction due to the kraft cooking process. Energy minimizations of structural evolution due to stretching along the x3 chain direction of the ‘swollen’ (kraft cooked) model identified chain rotation about the chain axis combined with inextensible secondary bonds as the most likely mechanism for auxetic response

    Rare and Insidious Toxicities from New Combination Therapies in Metastatic Renal Cell Cancer: Lessons Learned from Real-Practice

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    The advent of immune checkpoint inhibitors in combination with multitarget tyrosine kinase inhibitors has become a standard first-line treatment for metastatic renal cell cancer. Along with survival improvement, new toxicities have emerged. Such adverse events are still complex to be managed and some of them are rare and could be insidious or even fatal. Medical oncologists dispose of guidelines about the management of toxicities from immune checkpoint inhibitors but not for combinations. Therefore, it is still difficult to properly attribute and manage additive or overlapping adverse events. We report two clinical cases regarding rare treatment-related endocrine toxicities—hypophysitis and thyroiditis—with particular focus on their management. To this purpose, immune checkpoint-related toxicities guidelines represent the starting point. However, their implementation with additional measures is needed, considering the increasing complexity of current clinical scenarios. The goal is to correctly recognize adverse events and address side effects, so as not to discontinue effective treatments. We, therefore, aim at discussing the points of proper management of toxicities and individuating potential areas of improvement

    Photoionization Dynamics of the Tetraoxo Complexes OsO4 and RuO4

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    The photoionization dynamics of OsO4 and RuO4, chosen as model systems of small-size mononuclear heavy-metal complexes, has been theoretically studied by the time-dependent density functional theory (TDDFT). Accurate experimental measurements of photoionization dynamics as a benchmarking test for the theory are reported for the photoelectron asymmetry parameters of outer valence ionizations of OsO4, measured in the 17-90 eV photon energy range. The theoretical results are in good agreement with the available experimental data. The observed dynamical behavior of partial cross sections and asymmetry parameters has been related to both the coupling to the continuum of discrete excited states, giving strong modulations in the photon energy dependency, and the atomic composition of the initial ionized states, which determines the rate of decay of ionization probability for increasing excitation energies. Overall, an extensive analysis of the photoionization dynamics for valence and core orbitals is presented, showing good agreement with all the available experimental data. This provides confidence for the validity of the TDDFT approach in describing photoionization of heavy transition element compounds, with the perspective of being used for larger systems. Further experimental work is suggested for RuO4 to gather evidence of the sensitivity of the theoretical method to the nature of the metal atom

    Instrumental activities of daily living in older patients with metastatic prostate cancer: results from the meet-URO network ADHERE prospective study

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    Instrumental activities of daily living (IADL) are significant health indicators closely related to executive functions and able to detect mild cognitive impairment. A decline in IADL usually precedes ADL limitation, including taking medications, and may therefore predict a cognitive decline. We aimed to investigate the association of patients’ IADL score with other clinical factors, with a particular focus on the presence of a caregiver, and the impact on adherence to androgen receptor pathway inhibitors (ARPIs) and survival outcomes within the Meet-URO 5—ADHERE study. It was a large prospective multicentre observational cohort study monitoring adherence to ARPIs in 234 metastatic castrate-resistant PC (mCRPC) patients aged ≥ 70. We observed an association between impaired IADL and lower geriatric G8 scores (p < 0.01), and lower adherence to ARPIs whether assessed by pill counting (p = 0.01) or self-reported by the patient himself (p = 0.03). The combination of an IADL < 6 and the absence of a caregiver resulted in a significantly high risk of non-adherence to the ARPIs at the multivariable analysis (HR 9.23, 95% confidence interval 2.28–37.43, p = 0.01). IADL alongside the geriatric G8 scales represent essential tools to identify frail and less auto-sufficient patients who are extremely vulnerable particularly if not supported by a caregiver and have the highest risk of nonadherence to ARPIs

    Valutazione della bont&#224; educativa dei casi clinici di ECCE, il programma di formazione a distanza (FAD) basato sulle evidenze destinato ai medici italiani

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    OBIETTIVO. Valutare la qualit\ue0 dei percorsi clinici di un programma FAD destinato a tutti i medici italiani verificando le loro propriet\ue0 psicometriche. METODI. AIFA ha lanciato un programma nazionale di sostegno dell\u2019informazione indipendente tramite la distribuzione gratuita ai medici di Clinical Evidence (CE). Sulla base dei contenuti di CE \ue8 stato sviluppato un programma FAD all\u2019interno del sistema di Educazione Continua in Medicina (ECM) dal nome ECCE, anch\u2019esso gratuito. I medici hanno accesso a CE online e ai relativi percorsi clinici. Superandoli il medico ottiene i crediti ECM. Nel corso del 2006 \ue8 stata valutata la qualit\ue0 di un campione di venti percorsi, su un totale di 120. La valutazione formale della qualit\ue0 dei 20 casi selezionati \ue8 avvenuta attraverso le seguenti dimensioni psicometriche: Giudizio generale sui percorsi da parte degli utilizzatori (face validity); Valutazione dei contenuti da parte di clinici esperti (content validity); Valutazione della attendibilit\ue0 del test attraverso un criterio di consistenza interna (internal reliability); Difficolt\ue0 degli items; Capacit\ue0 del test di rilevare una modificazione della conoscenza (responsiveness). RISULTATI: Alcune migliaia di utenti hanno partecipato alla valutazione fornendo esiti contrastanti: mentre la face e content validity sono state valutate positivamente dagli utilizzatori e dai clinici esperti, altri parametri come l\u2019internal reliability e la difficolt\ue0 degli items hanno mostrato grande variabilit\ue0 tra i percorsi. Sette casi mostrano un valore di alpha complessivo inferiore a 0.50 (soglia minima di affidabilit\ue0). I casi si sono dimostrati nel complesso medio-facili. Facendo riferimento solo alle proprie conoscenze i partecipanti rispondevano correttamente a circa a met\ue0 delle domande. La lettura delle fonti era associata a un miglioramento della performance (miglioramento prima-dopo statisticamente significativo, p<0.05 per 19/20 percorsi). CONCLUSIONI: L\u2019importante eterogeneit\ue0 tra percorsi dimostrerebbe come differenti casi possono analizzare in maniera molto disomogenea il domino conoscenza evidence-based derivata dai contenuti di CE
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