814 research outputs found
The Columbus logistics support at the APMC: Requirements and implementation aspects
This paper focuses on the logistics support to be provided by the APM Center (APMC). Among the Columbus ground infrastructures, this center is tasked to provide logistics, sustaining engineering and P/L integration support to the ongoing missions of the APM, i.e. the Columbus Laboratory attached to the Freedom Space Station. The following is illustrated: an analysis of the requirements that are levied on the logistics support of the APM; how such requirements are reflected in the corresponding support to be available on-ground and at APMC; the functional components of the APMC logistics support and how such components interact each other; how the logistics support function interfaces with the other functions of the ground support; and how the logistics support is being designed in terms of resources (such as hardware, data bases, etc.). Emphasis is given to the data handling aspects and to the related data bases that will constitute for the logistics activities the fundamental source of information during the APM planned lifetime. Functional and physical architectures, together with trades for possible implementation, are addressed. Commonalities with other centers are taken into account and recommendations are made for possible reuse of tools already developed in the C/D phase. Finally, programmatic considerations are discussed for the actual implementation of the center
Efficient three-dimensional survey techniques and their comparison in open software in the archaeological test site of "Ninfeo Maggiore" and "Ninfeo Minore" of Formia (Latina, Italy)
In Europe and beyond, the cultural and archaeological heritage may have considerable extensions of hundreds of square metres if not kilometres. It is then necessary to study highly efficient techniques able , at the same time, to maintain centimetric accuracy. In these contexts, the SLAM technique can be an efficient solution. We tested the latter in a survey of a portion of the so-called Roman Villa of Caposele, also known as Villa Rubino in Formia, (Italy): the "Ninfeo Maggiore"and "Ninfeo Minore"(Major and Minor nymphaeum). The two structures had to be surveyed for both conservation and study purposes and to allow a virtual visit, which is particularly important since they are located inside a private property. The structure is complex, with a succession of rooms and environments in an archaeological complex extending approximately 480 metres in an east-west direction and approximately 50 metres in a south-north direction. We decided to survey both nymphaea with the "GEOSLAM Zeb Horizon", also surveying all the internal connecting rooms and corridors between them. Both nymphaea were also surveyed with a "Faro"terrestrial laser scanning, to allow comparison. To verify the validity of the SLAM on the outside, a survey was carried out using a DJI Matrix drone with laser scanning. The comparison showed very limited deviations whose statistical validation is in progress, demonstrating that the SLAM technique can advantageously be used in such vast archaeological complexes where the efficiency and completeness of the survey is more important than the millimetric accuracy.</p
Ferroelectric order driven Eu3+ photoluminescence in BaZrxTi1−xO3 perovskite
The ability to tune and enhance the properties of luminescent materials is essential for enlarging their application potential. Recently, the modulation of the photoluminescence emission of lanthanide-doped ferroelectric perovskites by applying an electric field has been reported. Herein, we show that the ferroelectric order and, more generally the polar order, has a direct effect on the photoluminescence of Eu3+ in the model BaZrxTi1-xO3 perovskite even in the absence of an external field. The dipole arrangement evolves with increasing xfrom long-range ferroelectric order to short-range order typical of relaxors until the non-polar paraelectric BaZrO3 is achieved. The cooperative polar interactions existing in the lattice (x < 1) promote the off-center displacement of the Eu3+ ion determining a change of the lanthanide site symmetry and, consequently, an abrupt variation of the photoluminescence emission with temperature. Each type of polar order is characterized by a distinct photoluminescence behaviour
Rejection sensitivity and social outcomes of young adult men with ADHD.
ABSTRACT Objective: Attention-Deficit/Hyperactivity Disorder (ADHD) has been consistently linked to social maladjustment. This study investigated whether elevated rejection sensitivity (RS) could contribute to the relational problems that adults with ADHD encounter. Method: Undergraduate men in ADHD-Combined Type (ADHD-C; n = 31), ADHD-Primarily Inattentive Type (ADHD-IA; n = 22), and nondiagnosed control (NC; n = 25) groups completed questionnaires concerning RS, relational history, current relationships, and self-esteem. Results: The hypothesis that those with ADHD would have elevated RS (versus NC peers) was not supported. However, low RS predicted divergent outcomes across groups. Furthermore, ADHD-IA men reported more negative relational outcomes than their ADHD-C peers, although both groups reported lower general self-esteem than controls. Conclusion: Perhaps the positive illusory bias associated with childhood ADHD could buffer RS development. Findings provide evidence of ADHD-related impairment in adult relationships, further differentiate the principal ADHD subtypes, and extend the RS literature to this clinical population
An Exploratory Assessment of Applying Risk Management Practices to Engineered Nanomaterials
The widespread industrial application of nanotechnology has increased the number of workers exposed to engineered nanomaterials (ENMs), but it is not clear to what extent prevention guidance is practiced. Our aim was to explore the extent that companies manufacturing and/or using ENMs apply risk assessment and management measures. Thirty-four companies were surveyed with an international 35-item questionnaire investigating company and workforce features, types of ENM handled, and risk evaluation and preventive measures adopted. Among participating companies, 62% had a maximum of 10 employees. Metal-based nanomaterials were most frequently identified (73%). Environmental monitoring was performed by 41% of the companies, while engineering exposure controls were approximately reported by 50%. Information and training programs were indicated by 85% of the sample, only 9% performed specific health surveillance for ENM workers. Personal protective equipment primarily included gloves (100%) and eye/face protection (94%). This small-scale assessment can contribute to the limited amount of published literature on the topic. Future investigations should include a greater number of companies to better represent ENM workplaces and a direct access to industrial settings to collect information on site. Finally, deeper attention should be paid to define standardized frameworks for ENM risk assessment that may guide nano-specific preventive actions
Psychometric properties of burnout measures: a systematic review.
Occupational Burnout (OB) is currently measured through several Patient-Reported Outcome Measures (PROMs) and some of them have become widely used in occupational health research and practice. We, therefore, aimed to review and grade the psychometric validity of the five OB PROMs considered as valid for OB measure in mental health professionals (the Maslach Burnout Inventory (MBI), the Pines' Burnout Measure (BM), the Psychologist Burnout Inventory (PBI), the OLdenburg Burnout Inventory (OLBI) and the Copenhagen Burnout Inventory (CBI)).
We conducted systematic literature searches in MEDLINE, PsycINFO and EMBASE databases. We reviewed studies published between January 1980 and September 2018 following a methodological framework, in which each step of PROM validation, the reference method, analytical technics and result interpretation criteria were assessed. Using the COnsensus-based Standards for the selection of health Measurement Instruments we evaluated the risk of bias in studies assessing content and criterion validity, structural validity, internal consistency, reliability, measurement error, hypotheses testing and responsiveness of each PROM. Finally, we assessed the level of evidence for the validity of each PROM using the GRADE approach.
We identified 6541 studies, 19 of which were included for review. Fifteen studies dealt with MBI whereas BM, PBI, OLBI and CBI were each examined in only one study. OLBI had the most complete validation, followed by CBI, MBI, BM and PBI, respectively. When examining the result interpretation correctness, the strongest disagreement was observed for MBI (27% of results), BM (25%) and CBI (17%). There was no disagreement regarding PBI and OLBI. For OLBI and CBI, the quality of evidence for sufficient content validity, the crucial psychometric property, was moderate; for MBI, BM and PBI, it was very low.
To be validly and reliably used in medical research and practice, PROM should exhibit robust psychometric properties. Among the five PROMs reviewed, CBI and, to a lesser extent, OLBI meet this prerequisite. The cross-cultural validity of these PROMs was beyond the scope of our work and should be addressed in the future. Moreover, the development of a diagnostic standard for OB would be helpful to assess the sensitivity and specificity of the PROMs and further reexamine their validity.The study protocol was registered in PROSPERO (CRD 42019124621)
Venice lagoon chlorophyll-a evaluation under climate change conditions: A hybrid water quality machine learning and biogeochemical-based framework
Climate change presents a significant challenge to lagoon ecosystems, which are highly valued coastal environments known for their provision of unique ecosystem services. As important as fragile, lagoons are vulnerable to both natural processes and anthropogenic activities, and this vulnerability is exacerbated by the impacts of climate change, which are likely to result in severe ecological consequences. The complexity of water quality (WQ) processes, characterized by compounding and interconnected pressures, highlights the importance of adequate sophisticated methods to estimate future ecological impacts on lagoon environments. In this setting, a hybrid framework is introduced where Machine Learning (ML) and biogeochemical (BGC) models are integrated in a sequential modelling approach. This integration exploits the unique strengths offered by both models. The ML model allows capturing and learning linear and nonlinear correlations from historical data; the BGC interprets and simulates complex environmental systems subject to compounded pressures, building on identified causal relationships. Multi-Layer Perceptron (MLP) and Random Forest (RF) ML algorithms are trained, validated and tested within the Venice lagoon case study to assimilate historical WQ data (i.e., water temperature, salinity, and dissolved oxygen) and spatio-temporal information (i.e., monitoring station location and month), and to predict changes in chlorophyll-a (Chl-a) conditions. Then, projections from the BGC model SHYFEM-BFM for 2019, 2050, and 2100 timeframes under RCP 8.5 are integrated into the ML model (composing the hybrid ML-BGC model) to evaluate Chl-a variations under future biogeochemical conditions forced by climate change projections. Moreover, the SHYFEM-BFM standalone Chl-a projections are also used to compare the hybrid and the BGC scenarios. Annual and seasonal Chl-a predictions are developed by classes based on two classification modes (median and quartiles) established on the descriptive statistics computed on historical data. Results from the case study showed as the RF successfully classifies Chl-a with an overall model accuracy of about 80% for the median and 61% for the quartiles modes. Concerning future climate change scenarios, results revealed a decreasing trend for the lowest Chl-a values (below the first quartile, i.e. 0.85 µg/l) moving to the far future (2100), with an opposite rising trend for the highest Chl-a values (above the fourth quartile, i.e. 2.78 µg/l). On the seasonal level, summer remains the season with the highest Chl-a values in all scenarios, although in 2100 a strong increase in higher Chl-a values is also expected during the springtime one. The proposed hybrid framework represents a valuable approach to strengthen both multivariate Chl-a modelling and scenarios analysis, by placing artificial intelligence-based models alongside biogeochemical models
Cometary ion drift energy and temperature at comet 67P-Churyumov/Gerasimeko
The Ion Composition Analyzer (ICA) on the Rosetta spacecraft observed both
the solar wind and the cometary ionosphere around comet
67P/Churyumov-Gerasimenko for nearly two years. However, observations of low
energy cometary ions were affected by a highly negative spacecraft potential,
and the ICA ion density estimates were often much lower than plasma densities
found by other instruments. Since the low energy cometary ions are often the
highest density population in the plasma environment, it is nonetheless
desirable to understand their properties. To do so, we select ICA data with
densities comparable to those of Rosetta's Langmuir Probe (LAP)/Mutual
Impedance Probe throughout the mission. We then correct the cometary ion energy
distribution of each energy-angle scan for spacecraft potential and fit a
drifting Maxwell-Boltzmann distribution, which gives an estimate of the drift
energy and temperature for 3521 scans. The resulting drift energy is generally
between 11--18 eV and the temperature between 0.5--1 eV. The drift energy shows
good agreement with published ion flow speeds from LAP during the same time
period and is much higher than the cometary neutral speed. We see additional
higher energy cometary ions in the spectra closest to perihelion, which can
either be a second Maxwellian or a kappa distribution. The energy and
temperature are negatively correlated with heliocentric distance, but the slope
of the change is small. It cannot be quantitatively determined whether this
trend is primarily due to heliocentric distance or spacecraft distance to the
comet, which increased with decreasing heliocentric distance.Comment: 9 pages, 10 figure
Cognitive Functions and White Matter Tract Damage in Amyotrophic Lateral Sclerosis: A Diffusion Tensor Tractography Study
BACKGROUND AND PURPOSE: ALS is predominantly a disease of the motor system, but cognitive and behavioral symptoms also are observed. DT MR imaging is sensitive to microstructural changes occurring in WM tracts of patients with ALS. In this study, we investigated the association between cognitive functions and extramotor WM tract abnormalities in ALS patients. MATERIALS AND METHODS: DT MR imaging was obtained from 16 nondemented patients with ALS and 15 healthy controls. Patients with ALS underwent a neuropsychologic and behavioral evaluation. DT tractography was used to asses the integrity of the CST, corpus callosum, and the major long-range association tracts. The relationship between DT MR imaging metrics and cognitive functions was tested by using linear model analyses, adjusting for age and clinical disability. RESULTS: Eleven patients (69%) scored below the fifth percentile in at least 1 cognitive test, and 2 of them had a mild executive impairment. Performances at tests assessing attention and executive functions correlated with DT MR imaging metrics of the corpus callosum, CST, and long association WM tracts bilaterally, including the cingulum, inferior longitudinal, inferior fronto-occipital, and uncinate fasciculi. Verbal learning and memory test scores were associated with fornix DT MR imaging values, whereas visual-spatial abilities correlated with left uncinate fractional anisotropy. CONCLUSIONS: WM tract degeneration is associated with neuropsychologic deficits in patients with ALS. DT tractography holds promise to gain insight into the role of the brain WM network abnormalities in the development of cognitive impairment in patients with ALS
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