170 research outputs found

    Probing modifications of General Relativity using current cosmological observations

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    We test General Relativity (GR) using current cosmological data: the cosmic microwave background (CMB) from WMAP5 (Komatsu et al. 2009), the integrated Sachs-Wolfe (ISW) effect from the cross-correlation of the CMB with six galaxy catalogs (Giannantonio et al. 2008), a compilation of supernovae Type Ia (SNe) including the latest SDSS SNe (Kessler et al. 2009), and part of the weak lensing (WL) data from CFHTLS (Fu et al. 2008, Kilbinger et al. 2009) that probe linear and mildly non-linear scales. We first test a model where the effective Newton's constant, mu, and the ratio of the two gravitational potentials, eta, transit from the GR value to another constant at late times; in this case, we find that standard GR is fully consistent with the combined data. The strongest constraint comes from the ISW effect which would arise from this gravitational transition; the observed ISW signal imposes a tight constraint on a combination of mu and eta that characterizes the lensing potential. Next, we consider four pixels in time and space for each function mu and eta, and perform a Principal Component Analysis (PCA) finding that seven of the resulting eight eigenmodes are consistent with GR within the errors. Only one eigenmode shows a 2-sigma deviation from the GR prediction, which is likely to be due to a systematic effect. However, the detection of such a deviation demonstrates the power of our time- and scale-dependent PCA methodology when combining observations of structure formation and expansion history to test GR.Comment: 14 pages, 10 figures. Minor modifications, version published by Phys. Rev.

    Bessel beam illumination reduces random and systematic errors in quantitative functional studies using light-sheet microscopy

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    Light-sheet microscopy (LSM), in combination with intrinsically transparent zebrafish larvae, is a choice method to observe brain function with high frame rates at cellular resolution. Inherently to LSM, however, residual opaque objects cause stripe artifacts, which obscure features of interest and, during functional imaging, modulate fluorescence variations related to neuronal activity. Here, we report how Bessel beams reduce streaking artifacts and produce high-fidelity quantitative data demonstrating a fivefold increase in sensitivity to calcium transients and a 20 fold increase in accuracy in the detection of activity correlations in functional imaging. Furthermore, using principal component analysis, we show that measurements obtained with Bessel beams are clean enough to reveal in one-shot experiments correlations that can not be averaged over trials after stimuli as is the case when studying spontaneous activity. Our results not only demonstrate the contamination of data by systematic and random errors through conventional Gaussian illumination and but,furthermore, quantify the increase in fidelity of such data when using Bessel beams

    Does Value Co-Creation Really Matter? An Investigation of Italian Millennials Intention to Buy Electric Cars

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    The present research aims to explore the determinants of (full) electric vehicle (EV) buying intention of Italian millennials focusing on the role that value co-creation initiatives might play in the buying decision-making process. Value co-creation initiatives in the EV domain are studied employing an enhanced version of the Theory of Reasoned Action which, in addition to the traditional variables of the model, also includes perceived importance of cars’ attributes. Structural Equation Modeling (SEM) is used to analyze the data collected though an online survey on 523 Italians aged 18–35. The outcomes provide recommendations to tailor proper initiatives to encourage millennials’ buying intention of electric vehicles supporting private companies in favoring the adoption of wide-spread pro-environmental behaviors among Italian youngsters

    Italian family with two independent mutations:3358T/A in BRCA1 and 8756delA in BRCA2 genes.

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    Hereditary breast/ovarian cancer is a well-characterized clinical entity, largely attributed to the inheritance of BRCA1 or BRCA2 mutations. Among general population, the mutation's frequency of these genes is very low; therefore, the identification of two independent mutations in the same family is a rare event. This study reports the presence of two mutations, one in the BRCA1 and the second in the BRCA2 gene in an Italian Caucasian kindred. This family is composed of more than 250 individuals, spanning through five generations, among which endogamy was a common phenomenon. Considering the tumor spectrum, this family is characterized by a high incidence of different types of cancer. In our study, we considered only three out of seven family units for BRCA1 and BRCA2 analysis. In one of the family units, we found independent mutations of both BRCA genes. The BRCA1 mutation on exon 11 (3358TA) was identified originally in the index case and subsequently in 18 members of this family, whereas the same mutation was not detected in a related family member with male breast cancer. The male breast cancer patient led to the identification, through mutational analysis, of a new BRCA2 mutation (8756delA). This BRCA2 mutation was also found in the male breast cancer patient's daughter. The discovery of the BRCA2 mutation allowed us to alert the patient's daughter who, otherwise, could be falsely reassured since she had a negative BRCA1 test

    Reliable Prediction of Post-Operative Complications’ Rate Using the G8 Screening Tool: A Prospective Study on Elderly Patients Undergoing Surgery for Kidney Cancer

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    Abstract: In the last years the incidence of renal neoplasms has been steadily increasing, along with the average age of patients at the time of diagnosis. Surgical management for localized disease is becoming more challenging because of patients’ frailty. We conducted a multi-center prospective study to evaluate the role of the G8 as a screening tool in the assessment of intra and post-operative complications of elderly patients ( 70 y.o.) undergoing surgery for kidney cancer. A total of 162 patients were prospectively enrolled between January 2015 to January 2019 and divided into two study groups (frail vs. not-frail) according to their geriatric risk profile based on G8 score. Several factors (i.e., age, CCI, ASA score, preoperative anemia, RENAL score, surgical procedures, and techniques) were analyzed to identify whether any of them would configure as a statistically significant predictor of surgical complications. According to the G8 Score, 90 patients were included in the frail group. A total of 52 frail patients vs. 4 non-frail patients developed a postoperative complication of any kind (p < 0.001). Of these, 11 were major complications and all occurred in the frail group. Our results suggest that the G8 screening tool is an effective and useful instrument to predict the risk of overall complications in elderly patients prior to renal surgery

    Energy management and load profile optimisation of 10 kWh BESS integrated into a Smart Polygeneration Grid subnetwork

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    Smart Polygeneration Grids integrate different prime movers, such as traditional generators, renewable energy sources and energy storage systems to locally supply electrical and thermal power to achieve high conversion efficiencies and increase self-consumption. Integrating different energy systems poses some challenges on the plant Energy Management Systems (EMS), which must accommodate different operational requirements while following the electrical and thermal loads. Battery Energy Storage Systems (BESSs) can provide additional flexibility to the system. This paper intends to evaluate the impact of integrating a Ni-Zn-based BESS into an existing cogeneration plant through a dedicated sensitivity analysis over the operative characteristics of the BESS itself (maximum power and capacity). The IES LAB of the Savona’s Campus already contains different energy systems: a cogenerative micro gas turbine, a heat-pump, solar thermal panels and two thermal energy storage systems that provide electricity and thermal power to the Smart Polygeneration Grid of the Campus. A new developed energy scheduler accommodates the integration of the new battery and meets the electrical and thermal demands. The aim is to demonstrate that integrating the BESS provides additional benefits in the system management and can reduce fuel usage and OPEX
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