699 research outputs found

    F-theory at order α3\alpha'^3

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    We study the effective physics of F-theory at order α3\alpha'^3 in derivative expansion. We show that the ten-dimensional type IIB eight-derivative couplings involving the graviton and the axio-dilaton naturally descend from pure gravity in twelve dimensions. Upon compactification on elliptically fibered Calabi-Yau fourfolds, the non-trivial vacuum profile for the axio-dilaton leads to a new, genuinely N=1, α3\alpha'^3 correction to the four-dimensional effective action.Comment: 24 pages, minor improvements, typos correcte

    Thermoelectric and microbattery hybrid system with its power management

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    Submitted on behalf of EDA Publishing Association (http://irevues.inist.fr/handle/2042/5920)International audienceIntegration of a power source with a MEMS to obtain an autonomous or remote system is a very challenging task. Such a device is currently being developed. It consists in hybriding an energy storage system (thin film solid state battery) with a scavenging energy system (thermogenerator) in a very small volume. It requires also power management to both control charge of the battery by the thermogenerator and discharge of the battery by the load, i.e. a sensor for instance

    In Silico clinical trial to predict the efficacy of hip protectors for preventing hip fractures

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    Osteoporosis is characterized by loss of bone mineral density and increased fracture risk. Reduction of hip fracture incidence is of major clinical importance. Hip protectors aim to attenuate the impact force transmitted to the femur upon falling, however different conclusions on their efficacy have been reported; some authors suggest this may be due to differences in compliance. The aim of this study was to apply an In Silico trial methodology to predict the effectiveness of hip protectors and its dependence on compliance. A cohort of 1044 virtual patients (Finite Element models of proximal femur) were generated. A Markov chain process was implemented to predict fracture incidence with and without hip protectors, by simulating different levels of compliance. At each simulated follow-up year, a Poisson distribution was randomly sampled to determine the number of falls sustained by each patient. Impact direction and force were stochastically sampled from a range of possible scenarios. The effect of wearing a hip protector was simulated by applying attenuation coefficients to the impact force (12.9 %, 19 % and 33.8 %, as reported for available devices). A patient was considered fractured when impact force exceeded the femur strength. Without hip protector, virtual patients experienced 66 +/- 5 fractures in 10 years. Wearing the three devices, fracture incidence was reduced to 43 +/- 4, 35 +/- 4 and 17 +/- 2 respectively, at full compliance. As expected, effectiveness was dependent on compliance. This In Silico trial technology can be applied in the future to test multiple interventions, optimise intervention strategies, improve clinical trial design and drug development

    Weather- and climate-driven power supply and demand time series for power and energy system analyses

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    Reaching net-zero carbon emissions requires large shares of intermittent renewable energy and the electrification of end-use consumption, such as heating, making the future energy system highly dependent on weather variability and climate change. Weather exhibits fluctuations on temporal scales ranging from sub-hourly to yearly while climate variations occur on decadal scales. To investigate the intricate interplay between weather patterns, climate variations, and power systems, we developed a database of time series of wind and solar power generation, hydropower inflow, heating and cooling demand using an internally consistent modeling framework. Here we focused on the European continent and generated country level time series extending between 1940 and 2100. Our database can be used for analyses aimed at understanding and addressing the challenges posed by the evolving energy landscape in the face of deep decarbonization and climate change

    Strategies to diagnose ovarian cancer: new evidence from phase 3 of the multicentre international IOTA study

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    Background: To compare different ultrasound-based international ovarian tumour analysis (IOTA) strategies and risk of malignancy index (RMI) for ovarian cancer diagnosis using a meta-analysis approach of centre-specific data from IOTA3. Methods: This prospective multicentre diagnostic accuracy study included 2403 patients with 1423 benign and 980 malignant adnexal masses from 2009 until 2012. All patients underwent standardised transvaginal ultrasonography. Test performance of RMI, subjective assessment (SA) of ultrasound findings, two IOTA risk models (LR1 and LR2), and strategies involving combinations of IOTA simple rules (SRs), simple descriptors (SDs) and LR2 with and without SA was estimated using a meta-analysis approach. Reference standard was histology after surgery. Results: The areas under the receiver operator characteristic curves of LR1, LR2, SA and RMI were 0.930 (0.917–0.942), 0.918 (0.905–0.930), 0.914 (0.886–0.936) and 0.875 (0.853–0.894). Diagnostic one-step and two-step strategies using LR1, LR2, SR and SD achieved summary estimates for sensitivity 90–96%, specificity 74–79% and diagnostic odds ratio (DOR) 32.8–50.5. Adding SA when IOTA methods yielded equivocal results improved performance (DOR 57.6–75.7). Risk of Malignancy Index had sensitivity 67%, specificity 91% and DOR 17.5. Conclusions: This study shows all IOTA strategies had excellent diagnostic performance in comparison with RMI. The IOTA strategy chosen may be determined by clinical preference

    Cumulative Prognostic Score Predicting Mortality in Patients Older Than 80 Years Admitted to the ICU.

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    OBJECTIVES: To develop a scoring system model that predicts mortality within 30 days of admission of patients older than 80 years admitted to intensive care units (ICUs). DESIGN: Prospective cohort study. SETTING: A total of 306 ICUs from 24 European countries. PARTICIPANTS: Older adults admitted to European ICUs (N = 3730; median age = 84 years [interquartile range = 81-87 y]; 51.8% male). MEASUREMENTS: Overall, 24 variables available during ICU admission were included as potential predictive variables. Multivariable logistic regression was used to identify independent predictors of 30-day mortality. Model sensitivity, specificity, and accuracy were evaluated with receiver operating characteristic curves. RESULTS: The 30-day-mortality was 1562 (41.9%). In multivariable analysis, these variables were selected as independent predictors of mortality: age, sex, ICU admission diagnosis, Clinical Frailty Scale, Sequential Organ Failure Score, invasive mechanical ventilation, and renal replacement therapy. The discrimination, accuracy, and calibration of the model were good: the area under the curve for a score of 10 or higher was .80, and the Brier score was .18. At a cut point of 10 or higher (75% of all patients), the model predicts 30-day mortality in 91.1% of all patients who die. CONCLUSION: A predictive model of cumulative events predicts 30-day mortality in patients older than 80 years admitted to ICUs. Future studies should include other potential predictor variables including functional status, presence of advance care plans, and assessment of each patient's decision-making capacity

    Hormonal Contraception and Bone Metabolism: Emerging Evidence from a Systematic Review and Meta-Analysis of Studies on Post-Pubertal and Reproductive-Age Women

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    Background/Objectives: This study aims to assess the effects of combined hormonal contraceptives (CHCs) on bone metabolism markers. It primarily measures osteocalcin and additionally examines other bone health markers, seeking to determine their responses to estrogen–progestogen treatments. Methods: This study involved a comprehensive evaluation of the pertinent literature and a meta-analysis explicitly conducted on data describing women of reproductive age. The analysis encompassed accessible papers ranging to December 2024 (i.e., those listed in PubMed/Medline, Embase, Scopus, the Cochrane Database, International Clinical Trials Registry, and ClinicalTrials.gov). We examined published randomized controlled trials (RCTs) and prospective studies. The quality of the studies was assessed using the Cochrane tool for RCTs and the Newcastle–Ottawa Scale for prospective studies. The selected indicators for primary and secondary outcomes were ascertained by standardized mean change (SMC), displaying the difference between conditions before and after treatment. Trends were evaluated using meta-regressions. Results: Ultimately, 34 articles out of 1924 identified items met the inclusion criteria, covering 33 unique studies. In EE/E4 combinations, osteocalcin dropped significantly (SMC −0.54 (CI.95 −0.64/−0.43) and −0.43 (CI.95 −0.76/−0.10)). Similar effects were observed for other bone-formation and reabsorption markers, with less significant reductions observed in E2-containing CHC (e.g., alkaline phosphatase (bone) EE combinations, SMC −0.39 (CI.95 −0.67/−0.11); P1NP E2 combination, 0.12 (CI.95 −0.10/0.33); and EE combinations, −0.55 (CI.95 −0.83/−0.26)). The reduction patterns also exhibited differences according to the women’s age (e.g., osteocalcin in EE combinations ≤21, SMC −0.63 (CI.95 −0.77/−0.49) and >21, SMC −0.42 (CI.95 −0.61/−0.24); alkaline phosphatase (bone) EE combinations ≤21, SMC −0.55 (CI.95 −0.86/−0.24) and >21, SMC −0.06 (CI.95 −0.47/0.35)). This analysis found that CHC maintains or reduces bone turnover in childbearing women, with effects varying by age and hormone combination. Moreover, bone-formation and reabsorption markers correlated positively to pro-androgenic progestins (p < 0.05). Thus, estrogen–progestogen combinations reduce bone turnover less when weak estrogens and a pro-androgenic or neutral progestin are present. Conclusions: This study found that CHCs reduce bone turnover, with natural estrogens and androgenic progestins appearing to be more beneficial than EE and anti-androgenic types. These findings would potentially influence decisions relevant to CHC prescriptions during a woman’s reproductive phases, emphasizing the need for additional research to tailor CHC usage to bone health

    One-Step Laparoscopic Management of a Female Adnexal Tumor of Wolffian Origin

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    We report a case of female adnexal tumor of Wolffian origin (FATWO), a rare neoplasm arising from the mesonephric ducts. A 48-year-old woman came first to our center for a recent discovery of a pelvic mass. Transvaginal ultrasonographic findings suggested a solid right para-ovarian mass suspected to be malignant. After thorough counseling, the patient underwent operative laparoscopy for excision of the para-ovarian mass with frozen section (FS) examination resulting in the diagnosis of a poorly differentiated adenocarcinoma. In this case, FS results allowed performing a comprehensive oncological staging, through a totally laparoscopic extrafascial hysterectomy, bilateral adnexectomy, total omentectomy, pelvic wall peritonectomy, and pelvic, parasacral and para-aortic lymphadenectomy. Final pathological and immunohistochemical results confirmed the diagnosis of FATWO. To our knowledge, this is the first case of FATWO managed entirely by a minimally invasive laparoscopic approach in a single surgical session

    Giant Sigmoid Diverticulum: A Rare Presentation of a Common Pathology

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    Although colonic diverticulum is a common disease, affecting about 35% of patients above the age of 60, giant sigmoid diverticulum is an uncommon variant of which only relatively few cases have been described in the literature. We report on our experience with a patient affected by giant sigmoid diverticulum who was treated with diverticulectomy. Resection of the diverticulum is a safe surgical procedure, provided that the colon section close to the lesion presents no sign of flogosis or diverticula; in addition, recurrences are not reported after 6-year follow-up
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