94 research outputs found
Evaluation of an optimized enzymatic biosensor for ethanol used in apple storage management with low oxygen stress
Ethanol has been proposed to be one of the target molecules to monitor the dynamic controlled atmosphere (DCA) technique during apple storage, measured in the squeezed juice or in the air of the storage chamber. One of the proposed commercial sensors for ethanol in apple juice is based on amperometry, after a two-step enzyme-based reaction that involves a diaphorase and an alcohol-dehydrogenase. Even though this method has been reported to overestimate ethanol, this difference is fairly fixed and it is industrially used to check the correct application of the treatment and to set the gas composition protocols when the maximum acceptable ethanol is reached. During the 2018 harvest, the ethanol concentration in juices measured with the commercial sensor appeared much higher than those usually reported in precedent years, particularly for the lower concentrations. Laboratory experiments suggested that differences between years could be due to the presence of a secondary enzyme activity present in the commercial diaphorase employed. In order to increase the sensitivity and accuracy, it has been evaluated the performance of the biosensor emploting a further diaphorase. The performances of both sensors were compared with those obtained with a gaschromatophy mass spectrometry approach after head space extraction (HS-GC-MS) in which the mass spectra was acquired in selected-ion monitoring mode. Samples belonging to ‘Red Delicious’ cv. were picked up at different temporary points from industrial storage rooms following the application of low oxygen stress. The new biosensor reduced 97% the mean difference respect to the values obtained with the GC-MS method. The difference between sensors was even clearer for samples with concentrations up to 100 mg/L, that could be used as a discriminating value for the evaluation of the technique success in ‘Red Delicious’ apple juice. The increased sensitivity of the sensor allowed a more accurate monitoring of the DCA at industrial conditions, limiting the risks linked to a false positive on the monitoring during storage
Detecting Recent Dynamics in Large-Scale Landslides via the Digital Image Correlation of Airborne Optic and LiDAR Datasets: Test Sites in South Tyrol (Italy)
Large-scale slow-moving deep-seated landslides are complex and potentially highly damaging phenomena. The detection of their dynamics in terms of displacement rate distribution is therefore a key point to achieve a better understanding of their behavior and support risk management. Due to their large dimensions, ranging from 1.5 to almost 4 km(2), in situ monitoring is generally integrated using satellite and airborne remote sensing techniques. In the framework of the EFRE-FESR SoLoMon project, three test-sites located in the Autonomous Province of Bolzano (Italy) were selected for testing the possibility of retrieving significant slope displacement data from the analysis of multi-temporal airborne optic and light detection and ranging (LiDAR) surveys with digital image correlation (DIC) algorithms such as normalized cross-correlation (NCC) and phase correlation (PC). The test-sites were selected for a number of reasons: they are relevant in terms of hazard and risk; they are representative of different type of slope movements (earth-slides, deep seated gravitational slope Deformation and rockslides), and different rates of displacement (from few cm/years to some m/years); and they have been mapped and monitored with ground-based systems for many years (DIC results can be validated both qualitatively and quantitatively). Specifically, NCC and PC algorithms were applied to high-resolution (5 to 25 cm/px) airborne optic and LiDAR-derived datasets (such as hillshade and slope maps computed from digital terrain models) acquired during the 2019-2021 period. Qualitative and quantitative validation was performed based on periodic GNSS surveys as well as on manual homologous point tracking. The displacement maps highlight that both DIC algorithms succeed in identifying and quantifying slope movements of multi-pixel magnitude in non-densely vegetated areas, while they struggle to quantify displacement patterns in areas characterized by movements of sub-pixel magnitude, especially if densely vegetated. Nonetheless, in all three landslides, they proved to be able to differentiate stable and active parts at the slope scale, thus representing a useful integration of punctual ground-based monitoring systems
A finer grained approach to psychological capital and work performance
Purpose
Psychological capital is a set of personal resources comprised by hope, efficacy, optimism, and resilience, which previous research has supported as being valuable for general work performance. However, in today’s organizations, a multidimensional approach is required to understanding work performance, thus, we aimed to determine whether psychological capital improves proficiency, adaptivity, and proactivity, and also whether hope, efficiency, resilience, and optimism have a differential contribution to the same outcomes. Analyzing the temporal meaning of each psychological capital dimension, this paper theorizes the relative weights of psychological capital dimensions on proficiency, adaptivity, and proactivity, proposing also that higher relative weight dimensions are helpful to cope with job demands and perform well.
Methodology
Two survey studies, the first based on cross-sectional data and the second on two waves of data, were conducted with employees from diverse organizations, who provided measures of their psychological capital, work performance, and job demands. Data was modeled with regression analysis together with relative weights analysis.
Findings
Relative weights for dimensions of psychological capital were supported as having remarkable unique contributions for proficient, adaptive, and proactive behavior, particularly when job demands were high.
Originality/Value
We concluded that organizations facing high job demands should implement actions to enhance psychological capital dimensions; however, those actions should focus on the specific criterion of performance of interest
Moderation in management research: What, why, when and how.
Many theories in management, psychology, and other disciplines rely on moderating variables: those which affect the strength or nature of the relationship between two other variables. Despite the near-ubiquitous nature of such effects, the methods for testing and interpreting them are not always well understood. This article introduces the concept of moderation and describes how moderator effects are tested and interpreted for a series of model types, beginning with straightforward two-way interactions with Normal outcomes, moving to three-way and curvilinear interactions, and then to models with non-Normal outcomes including binary logistic regression and Poisson regression. In particular, methods of interpreting and probing these latter model types, such as simple slope analysis and slope difference tests, are described. It then gives answers to twelve frequently asked questions about testing and interpreting moderator effects
Mining Big Data for Tourist Hot Spots: Geographical Patterns of Online Footprints
Understanding the complex, and often unequal, spatiality of tourist
demand in urban contexts requires other methodologies, among which the information base available online and in social networks has gained prominence. Innovation
supported by Information and Communication Technologies in terms of data access
and data exchange has emerged as a complementary supporting tool for the more traditional data collection techniques currently in use, particularly, in urban destinations
where there is the need to more (near)real-time monitoring. The capacity to collect
and analise massive amounts of data on individual and group behaviour is leading to
new data-rich research approaches. This chapter addresses the potential for discovering geographical insights regarding tourists’ spatial patterns within a destination,
based on the analysis of geotagged data available from two social networks.
·info:eu-repo/semantics/publishedVersio
Physician Practice Patterns and Variation in the Delivery of Preventive Services
BACKGROUND: Strategies to improve preventive services delivery (PSD) have yielded modest effects. A multidimensional approach that examines distinctive configurations of physician attributes, practice processes, and contextual factors may be informative in understanding delivery of this important form of care. OBJECTIVE: We identified naturally occurring configurations of physician practice characteristics (PPCs) and assessed their association with PSD, including variation within configurations. DESIGN: Cross-sectional study. PARTICIPANTS: One hundred thirty-eight family physicians in 84 community practices and 4,046 outpatient visits. MEASUREMENTS: Physician knowledge, attitudes, use of tools and staff, and practice patterns were assessed by ethnographic and survey methods. PSD was assessed using direct observation of the visit and medical record review. Cluster analysis identified unique configurations of PPCs. A priori hypotheses of the configurations likely to perform the best on PSD were tested using a multilevel random effects model. RESULTS: Six distinct PPC configurations were identified. Although PSD significantly differed across configurations, mean differences between configurations with the lowest and highest PSD were small (i.e., 3.4, 7.7, and 10.8 points for health behavior counseling, screening, and immunizations, respectively, on a 100-point scale). Hypotheses were not confirmed. Considerable variation of PSD rates within configurations was observed. CONCLUSIONS: Similar rates of PSD can be attained through diverse physician practice configurations. Significant within-configuration variation may reflect dynamic interactions between PPCs as well as between these characteristics and the contexts in which physicians function. Striving for a single ideal configuration may be less valuable for improving PSD than understanding and leveraging existing characteristics within primary care practices
Stratigrafia e facies al limite Permiano-Triassico nelle Dolomiti occidentali (Provincia di Bolzano, Italia): una revisione.
Vengono presentati in questo lavoro i risultati dell\u2019analisi stratigrafica e delle microfacies di un intervallo
che contiene il limite Permiano-Triassico (P-T), in quattro sezioni stratigrafiche ubicate nelle Dolomiti occidentali
(Masi Saracini, Sass de Putia W, Seres e Bulla), gi\ue0 oggetto di numerosi studi negli ultimi 30 anni.
Abbiamo controllato la posizione e la qualit\ue0 dei dati di campagna, originali o tratti dalla letteratura, e li abbiamo
ottimizzati in modo da evitare sia la sovrapposizione di informazioni, sia la loro ripetizione artificiale
nel record stratigrafico. Abbiamo esaminato al microscopio e interpretato le microbiofacies che compaiono nei
tre cicli trasgressivi-regressivi (C1,...,C3), ciascuno dei quali \ue8 spesso da circa 1 m ad alcune decine di metri,
che compongono la successione. Le microbiofacies basali e di tetto di ciascun ciclo sono caratteristiche rispettivamente
delle veloci fasi trasgressive e regressive; queste ultime sono visibili solo in alcuni siti, ove furono
preservate dall\u2019erosione subaerea e da quella connessa con il processo trasgressivo (ravinement) successivi. Le
microbiofacies della parte mediana dei cicli sono invece meno diagnostiche, in quanto i diversi componenti
(alghe calcaree, gasteropodi, micro- e macroforaminiferi, crinoidi e bivalvi) risultano quasi ovunque fortemente
mescolati. La causa risiede, almeno per il tratto sommitale della Formazione a Bellerophon (i.e. Membro di
Bulla) nell\u2019elevata energia delle correnti di tempesta che spazzavano il fondale, profondo alcuni metri, del
settore nord-occidentale del Bellerophon Gulf. Un aiuto per l\u2019interpretazione paleogeografica \ue8 fornito dalla
distribuzione spaziale dei grandi brachiopodi (Comelicania sp.) la cui presenza, poco-nulla rimaneggiata, indica
le aree di altofondo, ricche di nutrimento.
Il limite fra la Formazione a Bellerophon e la sovrastante Formazione di Werfen \ue8 caratterizzato da una
breve e intensa fase regressiva (shallowing), che segna l\u2019inizio del pi\uf9 forte evento di scomparsa-estinzione
(ME3) nella paleo-Tetide occidentale. Il fortissimo impoverimento dei taxa a scheletro calcareo caratterizza
l\u2019accumulo trasgressivo basale (ravinement) della Formazione di Werfen, e si accompagna con la comparsa di
microbialiti e stromatoliti anche domiformi e delle ooliti. Queste ultime divengono via via pi\uf9 grandi e meglio
formate verso l\u2019alto, ad indicare la stabilizzazione almeno momentanea dell\u2019ambiente marino. L\u2019importante
evento biologico di estinzione ME3 deriv\uf2 da un rapido e complesso cambiamento climatico (pi\uf9 caldo e arido),
che sconvolse gli habitat marini di bassa profondit\ue0 e le aree continentali intorno alla paleo-Tetide occidentale. In questo caso, infatti, la distribuzione latero-verticale
dei sedimenti e delle microbiofacies segue logiche biologiche
e meccaniche quasi-casuali, secondo modelli illustrati
recentemente in ambienti attuali di piana tidale
bahamiana. La prima apparizione evolutiva del conodonte
Hindeodus parvus avviene in questo contesto paleogeografico stressato, poco pi\uf9 di 1 m sopra ME3. Per
finire, le quattro mappe paleogeografiche presentate in
questo lavoro, pur se riferite a brevi periodi di tempo
(migliaia-decine di migliaia di anni) in corrispondenza
di eventi circa isocroni (limiti di cicli o di parasequenze
deposizionali) e corroborati da dati biostratigrafici certi,
hanno un carattere schematico
Phthalates determination in wine and spirits using GC-MS and LC-MS/MS
Phthalates, widely studied in the last years as insidious and ubiquitous contaminants
of industrially processed foods, have recently been reported also in some wines and spirits. This work presents and compares the performances of two novel analytical approaches for the simultaneous determination of seventeen phthalates (i.e. DMP, DEP, DiBP, DBP, DMEP, BMPP, DEEP, DPP, DHXP, BBP, DBEP, DCHP, DEHP, DPhP, DNOP, DNP, DiNP; EN ISO 1043-3:1999 D) using mass spectrometry in alcoholic beverages. GC-MS analysis requires a preliminary time-consuming sample extraction, the use of perfectly cleaned glassware, highlypurified
extraction solvents, and the concentration of the final organic extract. LC-MS/MS
method is faster (no LLE and concentration steps) and more sensitive, even if it requires ultrapurified eluents, or the adoption of an on-line device for the background removal. Both approaches proved to be rugged and useful for routine and high-throughput analysis. DEHP, DiBP, DBP, DMEP and DiNP were present in more than 70% of spirits, while DBP and DNOP were quantifiable in 60% of wine
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