379 research outputs found
Indoor radon survey in university buildings: a case study of Sapienza - University of Rome
The indoor radon concentration in underground workplaces pertaining to Sapienza – University of Rome have been monitored since the 90’s according to prescription of Italian Legislative Decree 230/95. In the last years, the recommendations contained in the Council Directive 2013/59/Euratom have shifted the focus to all indoor exposure situations by promoting actions to identify workplaces and dwellings with radon concentrations exceeding the reference level of 300 Bq/m3. In response to the upcoming transposition into national legislation, Sapienza has promoted the first Italian survey addressing workplaces in university buildings, regardless of the position with respect to the ground floor.
The survey has interested more than three hundred workplaces, i.e. administration and professors’ offices, research and educational laboratories, conference rooms and classrooms, distributed in fifteen different buildings. Places monitored are strongly heterogeneous in terms of users’ habit, occupancy pattern and building characteristics. The influence of these parameters into seasonal variation have been addressed by organizing the survey in four quarters. The indoor radon concentration is measured by solid state nuclear track detectors, CR39.
The aim of the paper is to present features, methods and intermediate results of the survey. The work, relying on the analysis of previous measurements interesting underground workplaces, focuses on methodology followed during all the preliminary and preparatory phases: active measurements by ionization chamber radon continuous monitor, radon progeny equilibrium factor estimations by radon daughters monitor, strategies for occupants’ awareness, positioning protocol and provisions to maximize representativity of results
GUARIGIONE DAL TUMORE AL SENO: UN TEMA DIBATTUTO
The cure from breast cancer: a discussed subject
Cancer survivorship is a worldwide growing area of research. There are currently two main methods to measure cancer survival: relative survival and cancer-specific survival. Only recently a parametric method was proposed to model cumulative incidences with multiple possible causes of death. The method can be used to evaluate the cure fraction and may be an alternative to relative survival. Parametric crude cumulative incidence estimates are given by transformation models with an improper parametric baseline function. Precisely the originally proposed Gompertz distribution was compared with a more flexible 4 parameters Log-Logistic distribution. The goodness of fit of the two different models can be investigated by bootstrap resampling. The 4 parameters Log-Logistic distribution can model non-monotonic hazard functions and may be more appropriate to model specific deaths with respect to the more simple Gompertz distribution, e.g. in the context of diseases with complex dynamics.
The two parametric improper distributions are used in this work to estimate the fraction of cured patients with breast cancer. The literature on the estimation of the cured fraction for breast cancer patients has developed during the last decades thanks to the availability of studies with long follow-up time, which was required by the type of pathology in question. Data from a two-group randomized controlled trial were used. From 1973 to 1980, 701 women were recruited with breast cancer measuring no more than 2 cm in diameter. Were randomly assigned 349 women to radical mastectomy and 352 to breast-conserving surgery, followed by radiotherapy to the ipsilateral mammary tissue. Thanks to a reliable classification of the causes of death, it was possible to analyse data using cause-specific mortality.
The 4 parameters Log-Logistic distribution appears to fit better breast cancer specific deaths with respect to the simpler Gompertz distribution. The results of the parametric modelling of competing risks are consistent with the results obtained analysing relative survival. Although there is statistical evidence of a cure fraction, in practical terms, it seems that 30 years after breast cancer the cure cannot be claimed yet
Blood inflammatory indices in goats around kidding
AbstractThe transition period of goats is often characterized by serious metabolic problems, mainly before parturition. These troubles are related to negative energy balance status, however all causes are not totally defined. To improve the knowledge about pathogenesis in this phase we have monitored the changes of some blood indices of lipomobilization and inflammation. Six blood samples were collected from 10 primiparous and 25 multiparous "Camosciata delle Alpi" goats after morning milking. Samples were collected around 20 and 7 days before parturition and on days 0, 3, 6 and 12 of lactation. Albumin, total protein, haptoglobin, ceruloplasmin, total cholesterol, NEFA, β-OH-butyrate (BHB), Ca, Mg and Zn were determined. Goats were grouped according to their BHB level before parturition: low (≤0.6 mmol/l; LOB), average (0.6÷1.09; AVB) and high (≥1.09 mmol/l; HIB) level. Furthermore, the AVB group was divided according to plasma haptoglobin level before parturition: low (<0.5 g/l) or high. The statistical..
Bacillus spp. Probiotic Strains as a Potential Tool for Limiting the Use of Antibiotics, and Improving the Growth and Health of Pigs and Chickens
The pressure to increasingly optimize the breeding of livestock monogastric animals resulted in antimicrobials often being misused in an attempt to improve growth performance and counteract diseases in these animals, leading to an increase in the problem of antibiotic resistance. To tackle this problem, the use of probiotics, also known as direct in-feed microbials (DFM), seems to be one of the most promising strategies. Among probiotics, the interest in Bacillus strains has been intensively increased in recent decades in pigs and poultry. The aim of the present review was to evaluate the effectiveness of Bacillus strains as probiotics and as a potential strategy for reducing the misuse of antibiotics in monogastric animals. Thus, the potential modes of action, and the effects on the performance and health of pigs (weaning pigs, lactation and gestation sows) and broilers are discussed. These searches yielded 131 articles (published before January 2021). The present review showed that Bacillus strains could favor growth in terms of the average daily gain (ADG) of post-weaning piglets and broilers, and reduce the incidence of post-weaning diarrhea in pigs by 30% and mortality in broilers by 6–8%. The benefits of Bacillus strains on these parameters showed results comparable to the benefit obtained by the use of antibiotics. Furthermore, the use of Bacillus strains gives promising results in enhancing the local adaptative immune response and in reducing the oxidative stress of broilers. Fewer data were available regarding the effect on sows. Discordant effects have been reported regarding the effect on body weight (BW) and feed intake while a number of studies have supported the hypothesis that feeding probiotics to sows could benefit their reproductive performance, namely the BW and ADG of the litters. Taken all the above-mentioned facts together, this review confirmed the effectiveness of Bacillus strains as probiotics in young pigs and broilers, favoring their health and contributing to a reduction in the misuse of direct in-feed antibiotics. The continuous development and research regarding probiotics will support a decrease in the misuse of antibiotics in livestock production in order to endorse a more sustainable rearing system in the near future
Modelling of broadband light sources based on InAs / INxGA1-xAS metamorphic quantum dots
We propose a design for a semiconductor structure emitting
broadband light in the infrared, based on InAs quantum dots
(QDs) embedded into a metamorphic 4-step-graded InxGa1-
xAs buffer with x = 0.10, 0.20, 0.30, 0.40. We developed a
model to calculate metamorphic QD energy levels based on
realistic QD parameters and on strain-dependent material
properties: results of simulations were validated against
experimental values. By simulating the broadband
metamorphic structure, we demonstrated that its light
emission can cover the whole 1.0 - 1.7 μm range with a
bandwidth of 550 nm at 10K.
The emission spectrum was then assessed under realistic
electrical injection conditions, at room temperature, through
device-level simulations based on a coupled drift-diffusion
and QD dynamics model. As metamorphic QD devices have
been already fabricated with satisfying performances we
believe that this proposal is a viable option to realize broader
band light-emitting devices such as superluminescent diodes
Broadband light sources based on InAs/InGaAs metamorphic quantum dots
We propose a design for a semiconductor structure emitting broadband light in the infrared, based on InAsquantum dots(QDs) embedded into a metamorphic step-graded InxGa1−xAs buffer. We developed a model to calculate the metamorphic QD energy levels based on the realistic QD parameters and on the strain-dependent material properties; we validated the results of simulations by comparison with the experimental values. On this basis, we designed a p-i-n heterostructure with a graded index profile toward the realization of an electrically pumped guided wave device. This has been done by adding layers where QDs are embedded in InxAlyGa1−x−yAs layers, to obtain a symmetric structure from a band profile point of view. To assess the room temperature electro-luminescenceemission spectrum under realistic electrical injection conditions, we performed device-level simulations based on a coupled drift-diffusion and QD rate equation model. On the basis of the device simulation results, we conclude that the present proposal is a viable option to realize broadband light-emitting devices
Critical Strain Region Evaluation of Self-Assembled Semiconductor Quantum Dots
A novel peak finding method to map the strain from high resolution transmission electron micrographs, known as the Peak Pairs method, has been applied to In(Ga) As/AlGaAs quantum dot (QD) samples, which present stacking faults emerging from the QD edges. Moreover, strain distribution has been simulated by the finite element method applying the elastic theory on a 3D QD model. The agreement existing between determined and simulated strain values reveals that these techniques are consistent enough to qualitatively characterize the strain distribution of nanostructured materials. The correct application of both methods allows the localization of critical strain zones in semiconductor QDs, predicting the nucleation of defects, and being a very useful tool for the design of semiconductor device
High performance platinum contacts on high-flux CdZnTe detectors
The need for direct X-ray detection under high photon flux with moderate or high energies (30–100 keV range) has strongly increased with the rise of the 4th Generation Synchrotron Light Sources, characterised by extremely brilliant beamlines, and of other applications such as spectral computed tomography in medicine and non-destructive tests for industry. The novel Cadmium Zinc Telluride (CZT) developed by Redlen Technologies can be considered the reference material for high-flux applications (HF-CZT). The enhanced charge transport properties of the holes allow the mitigation of the effects of radiation induced polarization phenomena, typically observed in standard CZT materials (LF-CZT) under high photon flux. However, standard LF-CZT electrical contacts led to inacceptable high dark leakage currents on HF-CZT devices. In this work, a detailed study on the characteristics of new optimized sputtered platinum electrical contacts on HF-CZT detectors is reported. The results from electrical and spectroscopic investigations, showed the best performances on HF-CZT detectors with platinum anode, coupled with both platinum or gold cathode. The morphology, structure, and composition of Pt/CZT contact have been analysed by means of Transmission Electron Microscopy (TEM) on microscopic lamellas obtained by Focused Ion Beam (FIB), highlighting the presence of CdTeO3 oxide at the metal semiconductor interface
Evaluation of carcass quality, body and pulmonary lesions detected at the abattoir in heavy pigs subjected or not to tail docking
BackgroundNowadays, body and tail lesions and respiratory disease are some of the greatest problems affecting the health and welfare of pigs. The aim of the study was to measure the prevalence of pleurisy, bronchopneumonia (enzootic pneumonia like lesions) and lesions on tail and body of heavy pigs subjected or not to tail docking through the inspection in Italian abattoirs. Additionally, the effect of tail docking and season was investigated on carcass quality (weight, % of lean meat, and Protected Designation of Origin (PDO) classification). For this purpose, a total 17.256 carcasses belonging to 171 batches from 103 farms were inspected in an Italian abattoir between 2019 and 2022. Enzootic pneumonia (EP) like lesions were scored according to the Madec and Derrien method, while pleurisy was scored using the Italian Slaughterhouse pleuritic evaluation system (SPES). For the tail and body, the lesions were scored according to Welfare Quality. The lesion score index (LSI) was calculated for each area. Data were analysed using a general linear model (GLM) including tail caudectomy, season and distance of the farm from the abattoir.ResultsThe warm season increased the percentage of lesions in carcasses in all parts of the body observed (P < 0.0001). The presence of undocked tail increased the LSI of the tail (P < 0.0001). The percentage of limbs lesions with score 2 and limbs LSI increase with increasing duration of transport (coef. = 0.003, P < 0.001; coef. = 0.008, P < 0.001; respectively). The hot carcass weight and the percentage of carcasses included in the PDO were higher in batches with docked tails (P = 0.027; P < 0.001, respectively), while the percentage of lean meat was higher in batches with undocked tails (P < 0.001). There was a negative correlation between the percentage of carcasses included in PDO and the LSI of tail (r = - 0.422; P < 0.001).ConclusionsIn conclusion, the presence of the undocked tail and the warm season can be considered risk factors for the prevalence of tail lesions, while long transport can increase limb lesions. Furthermore, the carcass weight and meat quality were negatively influenced by tail lesions
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