2,000 research outputs found
Low-temperature bonding of temperature-resistant electronic connections
Bonding of flat metal surfaces utilizes low temperature melting intermediate material, pulse heating, and pressure application to produce strong, electrically conductive bond resistant to melting at temperatures well above melting point of intermediate material. Little or no intermediate material remains at the interface
A Bayesian High-Frequency Estimator of the Multivariate Covariance of Noisy and Asynchronous Returns
A multivariate positive definite estimator of the integrated covariance matrix of noisy and asynchronously observed asset returns is proposed. We adopt a Bayesian Dynamic Linear Model where microstructure noise is interpreted as measurement error, and asynchronous trading as missing observations in an otherwise synchronous series. Missing observations are treated as any other parameter, as typical in a Bayesian framework. An augmented Gibbs algorithm is used since all full conditionals are available and its convergence and robustness are discussed. A realistic simulation study compares our estimator with existing alternatives, under different liquidity and microstructure noise conditions. The results suggest that our estimator is superior in terms of RMSE particularly under severe conditions, such as portfolios of assets with heterogeneous liquidity and high level of microstructure noise. The application to the empirical dataset of ten tick-by-tick stock price series confirms the simulation results
10/26/1990 - Marching Panthers Morgan Humphrey and Tina Kramer
“Misurare la soddisfazione” è la sfida di approfondite ricerche e l’obiettivo di molte strategie di marketing. L’assunto di base è che un consumatore soddisfatto tende a reiterare i suoi comportamenti d’acquisto, a parità di ogni altra condizione o vincolo. Tradizionalmente, la soddisfazione è stata misurata come l’esito di un raffronto positivo tra le attese sviluppate prima dell’acquisto e i risultati ottenuti con l’utilizzo del bene acquistato. Tuttavia, nelle società di oggi, con la prevalenza dei consumi simbolici su quelli materiali, la frammentazione delle richieste del mercato, la vicinanza in tempo reale alle comunità di clienti, il rapporto instaurato coi beni acquistati non è quasi mai solo razionale, ma assume i connotati di un’esperienza totalitaria, emotiva e coinvolgente. Questo lavoro parte dall’assunto che la soddisfazione derivi, piuttosto che dalla specifica performance del prodotto, dalla valutazione dell’intera esperienza di consumo, dal momento in cui il prodotto è scelto a quello in cui ci si disfa. Sulla base di un innovativo approccio, il Modello conoscenze-speranze, essa è vista come un incremento dello stock di benessere soggettivo, esito di un raffronto con quanto razionalmente atteso ed emotivamente sperato. In quest’ottica, la soddisfazione risulta connessa con gli aspetti delle esperienze legati alla curiosità , alla divergenza, alla capacità di comportarsi e relazionarsi e, al contempo, con gli aspetti più propriamente sensoriali, simbolici ed estetici del consumo, che fanno appello alle emozioni più profonde ed agli affetti delle persone.
Il volume è articolato in quattro parti – a vantaggio di quanti, studiosi e operatori, desiderino misurare con validità scientifica e rigore la soddisfazione nei diversi ambiti di consumo. Nella prima, sono passati in rassegna i principali studi sulla soddisfazione, come base per una revisione critica del paradigma tradizionale realizzata con la proposizione del nuovo modello interpretativo. Nella seconda parte, è sviluppata la scala di soddisfazione derivante dalle esperienze di consumo, rispettivamente, in rapporto ai prodotti shopping, convenience, specialty e ai servizi. Nella terza parte, sono presentate delle applicazioni della scala in campo bancario, assicurativo e distributivo, oltre che in relazione ad un costrutto alternativo collegato, la customer delight, concludendo con una rassegna sistematica degli effetti comportamentali, positivi o negativi, e delle conseguenti strategie di marketing da parte delle imprese. La quarta parte, infine, fornisce una vasta appendice didattica contenente tutti i passaggi statistici, gli output e i comandi del software SPSS-PASW, per condurre le analisi contenute nel volume
Application of cross-linked rice starches as drug delivery matrices in monolithic tablets
The sustained release properties of regular and waxy rice starches and their derivatives were studied in tablets. The starches were cross-linked to different levels with epichlorohydrin, and the sustained release properties, swelling power, and rheological characteristics of the matrices prepared were determined. Propranolol hydrochloride was used as a model drug. The sustained release properties of waxy rice starch improved with increasing cross-linking levels, whereas cross-linking had little impact on the functionality of regular rice starch matrices. There was an increase in swelling power for both regular and waxy rice starches as cross-linking levels increased. Both starches showed an increase in the storage modulus when cross-linking was increased, with the regular rice starch matrices showing greater differences among samples. Regular rice starch matrices showed an independence of frequency as cross-linking increased, indicating a “true gel” characteristic, whereas waxy rice matrices behaved as a “weak gel.” Both regular and waxy rice starches displayed a decrease in creep and recovery profiles with an increase in cross-linking level. Waxy rice starch showed potential as a sustained release agent in tablets
Analisi di variabili climatiche in funzione della comprensione della variabilit? planctonica (caso di studio: Golfo di Trieste)
No abstract available in english.Con questo lavoro si presenta il confronto fra le rianalisi ERA-40 e i dati osservati alla stazione meteo di Trieste, finalizzato all\u27individuazione delle variabili pi? appropriate per lo studio degli effetti del clima sul plancton. Per quello che riguarda pressione a livello del mare, i primi risultati indicano un accordo quasi completo (r=0,99) fra rianalisi e osservazioni. Si riscontra invece una generale sottostima della velocit? del vento da parte degli ERA-40 rispetto ai dati locali. Le rianalisi ERA-40, per via della loro omogeneit? spazio-temporale, restano appropriate per la costruzione di mappe di regressione temporale rispetto alla serie planctoniche. Sono indicati gli anni anomali rispetto a queste due variabili e alla SST
Enabling monocular depth perception at the very edge
Depth estimation is crucial in several computer vision applications, and a recent trend aims at inferring such a cue from a single camera through computationally demanding CNNs - precluding their practical deployment in several application contexts characterized by low-power constraints. Purposely, we develop a tiny network tailored to microcontrollers, processing low-resolution images to obtain a coarse depth map of the observed scene. Our solution enables depth perception with minimal power requirements (a few hundreds of mW), accurately enough to pave the way to several high-level applications at-the-edge
Effect of layered double hydroxide intercalated with fluoride ions on the physical, biological and release properties of a dental composite resin
OBJECTIVES:
The aim of this work was the preparation of a new fluoride-releasing dental material characterized by a release of fluoride relatively constant over time without any initial toxic burst effect. This type of delivery is obtained by a matrix controlled elution and elicits the beneficial effect of a low amount of fluoride on human dental pulp stem cells (hDPSCs) towards mature phenotype.
METHODS:
The modified hydrotalcite intercalated with fluoride ions (LDH-F), used as filler, was prepared via ion exchange procedure and characterized by X-ray diffraction and FT-IR spectroscopy. The LDH-F inorganic particles (0.7, 5, 10, 20wt.%) were mixed with a photo-activated Bis-GMA/TEGDMA (45/55wt/wt) matrix and novel visible-light cured composites were prepared. The dynamic thermo-mechanical properties were determined by dynamic mechanical analyzer. The release of fluoride ions in physiological solution was determined using a ionometer. Total DNA content was measured by a PicoGreen dsDNA quantification kit to assess the proliferation rate of hDPSCs. Alkaline phosphatase activity (ALP) was measured in presence of fluoride resins.
RESULTS:
Incorporation of even small mass fractions (e.g. 0.7 and 5wt.%) of the fluoride LDH in Bis-GMA/TEGDMA dental resin significantly improved the mechanical properties of the pristine resin, in particular at 37°C. The observed reinforcement increases on increasing the filler concentration. The release of fluoride ions resulted very slow, lasting months. ALP activity gradually increased for 28 days in hDPSCs cell grown, demonstrating that low concentrations of fluoride contributed to the cell differentiation.
CONCLUSIONS:
The prepared composites containing different amount of hydrotalcite filler showed improved mechanical properties, slow fluoride release and promoted hDPSCs cell proliferation and cell differentiation
A Neural-based Algorithm for Landslide Detection at Stromboli Volcano: Preliminary Results.
This study presents a neural-based algorithm for the automatic detection
of landslides on Stromboli volcano (Italy). It has been shown that landslides are an
important short-term precursor of effusive eruptions of Stromboli. In particular, an
increase in the occurrence rate of landslides was observed a few hours before the
beginning of the February 2007 effusive eruption. Automating the process of
detection of these signals will help analysts and represents a useful tool for the
monitoring of the stability of the Sciara del Fuoco flank of Stromboli volcano. A
multi-layer perceptron neural network is here applied to continuously discriminate
landslides from other signals recorded at Stromboli (e.g., explosion quakes, tremor
signals), and its output is used by an automatic system for the detection task. To
correctly represent the seismic data, coefficients are extracted from both the
frequency domain, using the linear predictive coding technique, and the time
domain, using temporal waveform parameterization. The network training and
testing was carried out using a dataset of 537 signals, from 267 landslides and 270
records that included explosion quakes and tremor signals. The classification
results were 99.5% predictive for the best net performance, and 98.7% when the
performance was averaged over the different net configurations. Thus, this
detection system was effective when tested on the 2007 effusive eruption period.
However, continuing investigations into different time intervals are needed, to
further define and optimize the algorithm
Sistemi di trasmissione WiFi per il monitoraggio sismico del Vesuvio
First-year engineering students at the University of Queensland used an interactive webbook to acquire information skills. These helped them search information resources for their projects, which they are required to undertake as part of the subject Introduction to professional engineering. The information skills exercise was an integral part of the project and worth 10% of the overall assessment. The exercises were only available on the Web, allowing the students to enter their answers from home or wherever they had access to the Internet. All answers were marked automatically using a database of all possible answers. Students were able to go back to check their answers. Students were assessed on both their responses to the exercises and also their final bibliography which largely reflected the impact of the webbook. The entire process was evaluated. This paper presents the process and the outcomes of the first-year engineering project involving use of WWW for information skills instruction. The webbooks can be found at http://www.library.uq.edu.au/9e105/
Expression of progesterone receptor membrane component-1 in bovine reproductive system during estrous cycle
Several reports suggest the participation of progesterone receptor membrane component 1 (PGRMC1) in progesterone signaling in the reproductive system. This study aimed at investigating the presence and localization of PGRMC1 in bovine ovary, oviduct and uterus, during the follicular and luteal phases of the estrous cycle. In the ovary, PGRMC1 has been detected in surface germinal epithelium, granulosa cells, theca cells and in the germinal vesicle of the oocytes at all stages of folliculogenesis. In the corpus luteum the expression of PGRMC1 was influenced by the stage of the estrous cycle. In the oviducts and in the uterus horns, PGRMC1 was immunolocalized in the luminal epithelium, in the muscle layer cells and in the endothelial cells. In the uterus, PGRMC1 was intensely localized also in the glandular endometrium. However, in the oviducts and in the uterus horns, the localization of PGRMC1 was independent on the stage of the estrous cycle and on whether evaluating the ipsilateral or the contralateral organ. In conclusion, the present immunohistochemical study showed that PGRMC1 is located in various compartments of the bovine female reproductive organs. With the exception of the corpora lutea, PGRMC1 localization showed similar pattern during different stages of the estrous cycle
- …