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The Empirical Mode Decomposition (EMD) is a fully non‐parametric analysis of frequency modes and trends in a given series that is based on the data alone. We have devised an improved strategy based on a series of best practicesto use EMD successfully in the analysis of the monthly time series of carbonyl sulfide (OCS) atmospheric mole fractions measured at NOAA network stations (2000–2020). Long‐term trends and intra‐ and inter‐annual variability has been assessed. After a phase of generally increasing mole fractions up to 2015, with a temporary decline around 2009, we found that the OCS atmospheric mole fraction subsequently decreased at all stations, reflecting a recent imbalance in its total sources and losses. Our analysis has revealed a characteristic time scale for variation of 8–10 years. The variance associated with this long‐term behavior ranges from ∼$\sim $15% to 40% of the total strength of the signal, depending on location. Apart from this complex long‐term behavior, the OCS time series show a strong annual cycle, which primarily results from the well‐known OCS uptake by vegetation. In addition, we have also found one more frequency of minor variance intensity in the measured mole fraction time‐history, which corresponds to periods in the range of 2–3 years. This inter‐annual variability of OCS may be linked to the Quasi‐Biennial Oscillation. The Empirical Mode Decomposition has arisen as a new paradigm for the processing and analysis of time series. The tool has been applied to multi‐year mole fraction measurements of an atmospheric gas, carbonyl sulfide (OCS), which has important implications for understanding and analyzing the carbon cycle. OCS is the most abundant sulfur‐containing trace gas in the atmosphere and has recently emerged as a putative proxy for the terrestrial photosynthetic uptake of CO2because OCS and CO2have the same diffusion pathway into leaves. The study has analyzed OCS at 14 cooperative stations, which are distributed all around the world. We have found a characteristic time scale for 8–10 years variation. Apart from this complex long‐term behavior, the OCS time series show a robust yearly cycle, primarily from OCS uptake by vegetation. Finally, we have also found one more frequency, which corresponds to periods in the range of 2–3 years. This inter‐annual variability of OCS may be linked to the Quasi‐Biennial Oscillation, which is an almost periodic oscillation of the winds of the equatorial stratosphere. Atmospheric carbonyl sulfide has decreased at NOAA network stations in recent yearsTime Series Analysis and trend identificationEmpirical Mode Decomposition identified many characteristic frequencies of variability, some compatible with Quasi Biennal Oscillation Atmospheric carbonyl sulfide has decreased at NOAA network stations in recent years Time Series Analysis and trend identification Empirical Mode Decomposition identified many characteristic frequencies of variability, some compatible with Quasi Biennal Oscillation

The levelling data at Colli Albani volcanic area in the period 1950–2006, describing the main results obtained in the last 60 years are analysed. In particular, the focus is on the last two double run levellings, carried out in 2002 and 2006 respectively. Before performing these surveys, the levelling network configuration had been improved with the installation of new benchmarks, taking into account the ground movements inferred from previous studies. The data analysis shows that the strong uplift (with a maximum value of about 30 cm), occurred in the period 1950–1994 along the NW–SE levelling line bordering the SW sector of the Colli Albani caldera—Amato and Chiarabba (Geophys Res Lett 22:1985–1988, 1995); Chiarabba et al. (Bull Volcanol 59:161–170, 1997); Feuillet et al. (J Geophys Res 109:B02308, 2004); Salvi et al. (Geophys Res Lett 31:L12606, 2004); Anzidei et al. (J Volcanol Geother Res 80:55–65, 1998); Riguzzi et al. (Phys Earth Plan Inter 177:79–87, 2009) seems to have stopped after 1994. In fact, at least for the areas covered by the 1997/1999 and 2002 levelling surveys, a subsidence was highlighted in the same area previously affected by the uplift, with maximum rates similar in modulus. On the other hand, from 2002 to 2006 there is evidence of a substantial stability in the southern part of the investigated area, while in the northern area from Albano Lake to Rome, a sharp uplift (maximum value of about 3 cm) is registered.

We have previously demonstrated that the expression of the soluble extracellular domain of the transmembrane ligand for Notch receptors, Jagged 1 (sJ1), in NIH 3T3 cells results in the formation of a matrix-dependent chord-like phenotype, the loss of contact inhibition of growth, and an inhibition of pro-alpha 1(I) collagen expression. In an effort to define the mechanism by which sJ1 induces this phenotype, we report that sJ1 transfectants display biochemical and cytoskeletal alterations consistent with the activation of Src. Indeed, cotransfection of sJ1 transfectants with a dominant-negative mutant of Src resulted in the loss of matrix-dependent chord formation and correlated with the restoration of type I collagen expression and contact inhibition of growth. We also report that the sJ1-mediated induction of Src activity and related phenotypes, including chord formation, may result from the inhibition of endogenous Jagged 1-mediated Notch signaling since it was not possible to detect an sJ1-dependent induction of CSL-dependent transcription in these cells. Interestingly, NIH 3T3 cells transfected with dominant-negative (but not constitutively active) mutants of either Notch 1 or Notch 2 displayed a similar Src-related phenotype as the sJ1 transfectants. These data suggest that the ability of sJ1 to mediate chord formation is Src-dependent and requires the repression of endogenous Jagged 1-mediated Notch signaling, which is tolerant to the destabilization of the actin cytoskeleton, a mediator of cell migration.

In this study, we propose a robuststatistical method to discern anomalous patternsin geoelectrical time series measured in a seismicarea of the Southern Apennine chain. First, a filteringprocedure to remove seasonal effects related tometeo-climatic fluctuations was carried out.Then, we selected an autoregressive model able todescribe the time fluctuations of geoelectricalsignals and propose a method to obtain an objectiveestimate of probability of occurrence for each extremeevent detected in the time series. Our applications inSouthern Italy allow us to hypothesize that theambiguity of short-term prediction is within thecomplicated dynamics of the physical processresponsible for electrical anomalies observed on theearth's surface.

Abstract:: The objective of this study has been to experimentally analyze the correlation structure of the strong temporal intermittency which characterizes pipe flow close to the transition to turbulence. In doing so transitional pipe flow has been analyzed by Laser Doppler velocimetry and the Reynolds number dependence of the covariance function has been studied. The range which has been analyzed covers the transition to turbulence and moderately developed turbulence (Reynolds number from 1 500 to 5 000). The correlation structure which has been evidenced is generally in agreement with the deterministic, dynamical, interpretation of temporal intermittency which explains the intermittent behavior as a result of a saddle node bifurcation. However, the analysis has evidenced fluctuations even before the onset of turbulence. The structure of these fluctuations is perfectly autoregressive which leads us to conclude that the transition to turbulence can be viewed as a transition from linear randomness to (non-linear) homogeneity.

This paper describes an integrated ground deformation and gravity network aimed at monitoring volcano-tectonic movements in the Campanian area (Southern Italy). It covers an area of more than 3000 km2, including the volcanic centres of Somma-Vesuvius, Campi Flegrei caldera and Ischia island. Levelling, EDM and gravity networks, as well as periodic and continuous GPS measurements are carried out. The aim of the network is twofold: monitoring ground deformations in the above mentioned volcanic areas, and studying the complex tectonics of the Campania Plain, a graben-like structure in which the Neapolitan volcanism is concentrated, in relation to the tectonics of the Southern Apennines and of the Tyrrhenian Basin. The monitoring network consists of larger-scale levelling, EDM and GPS networks covering the whole Campania Plain, connected to the relatively stable areas of Apennines, together with smaller scale networks aimed at accurately monitoring the Somma-Vesuvius volcano, one of the most dangerous over the World due to the high degree of urban development. The Somma-Vesuvius is monitored by levelling network, over 200 km long, by periodic EDM and GPS measurements and by a small network of continuously recording GPS receivers. Moreover, high precision gravimetry is also employed to deep the knowledge of the dynamic framework of the area. The main results indicate that Mt. Vesuvius and the island of Ischia are currently quiescent, while Campi Flegrei are subject to significant slow vertical ground movements, known as “bradyseism”. Recently, two large uplifts, both of about 1.8 m, affected the area respectively in 1970–72 and 1982–84.

The performance of the Infrared Atmospheric Sounding Inteferometer (IASI), which is under development at the laboratories of the French National Space Agency, has been evaluated on the basis of new radiometric noise data. An error analysis has been performed for the direct and simultaneous estimation of temperature, water vapour, and ozone profiles.

The present investigation examined the empirical and theoretical validity of an instrument developed to assess family members' perceptions of needs following the brain injury of a relative. The Family Needs Questionnaire FNQ consists of 40 items reflecting commonly reported family needs. The development of the items was based on the literature describing family reactions to brain injury and other medical disabilities. A principal-components factor analysis was executed based on the FNQ responses of 178 family members. A six-factor solution was selection as the best fit for the data, yielding the following independent subscales: 1 Need for Health Information; 2 Need for Emotional Support; 3 Need for Instrumental Support; 4 Need for Professional Support; 5 Need for a Support Network; and 6 Need for Involvement with Care. Further analysis indicated at least adequate internal reliability for each scale. Overall, the measure appears to offer unique information relevant to family members' needs after brain injury.

Measurements of aerosol optical depth are presented in the spectral interval 0.40-1.10 μm, which includes the most transparent region of the solar spectrum and the near infrared. The measurements were obtained by a grating spectrometer with a resolution ≈ 0.5 nm during the 1994 summer season at a mountain site (about 850 m above sea level) in the South of Italy. Spectral regions free from gas absorption features have been singled out and used to retrieve the aerosol columnar size distribution. Inversions have been performed by using the Phillips-Twomey inversion method along with a χ2 criterion which allows one to choose a suitable value for the regularization parameter. The result of the inversions are presented in the particle radius range 0.1 ÷ 3 μm and indicate the presence of a bimodal aerosol with the second mode radius at about 1.0 μm undergoing transformations which are well correlated with relative humidity.

Mitogenic stimulation of peripheral blood lymphocyte cultures obtained from 36 thorium workers was studied to determine whether the response of these cells was affected by the individuals' occupational exposure to alpha irradiation. The standard assay involved incubating 2 × 105 lymphocytes per test well for 72 hours in the presence of phytohemagglutinin (PHA), concanavalin A (Con A) or pokeweed mitogen (PWM). The results showed that there was a significant decrease in lymphocyte responsiveness of former thorium workers grouped by decade of life when compared with controls of the same decade of life for each mitogen tested with the exceptions of PHA in the 41-50 age group and PWM in the 51-60 age group. We are unable to correlate the decreased response observed with the measured body burdens, external gamma exposure, or thoron exhalation rates in these thorium cases. However, other occupational exposures (i.e., various chemicals used in processing thorium) cannot be eliminated as a possible cause.

This paper focuses on a method proposed for diagnosing the presence of chaotic behaviour in physical systems directly from experimental time series. The procedure relies on the concept of short-term predictability of chaotic motions. From a statistical point of view, it is completely non-parametric and works whatever the distribution function of the data points may be. The method is robust to observational noise, and can distinguish merely linear stochastic processes,e.g., fractional Brownian motion, from truly non-linear deterministic systems. The capability of the method has been evaluated by applying it to intermittent gas-liquid flows in a horizontal pipe. A weak sign of deterministic chaos has been diagnosed in plug and slug flow regimes. Our analysis fully confirms the Ruelle-Takens view about the complexity in hydrodynamical systems. However, the weak sign of chaos is in contrast with the Lorenz type systems (strong chaos) and supports the idea of Kolmogorov about irregular motion in hydrodynamical systems.

A new cloud clearing procedure applied to High-resolution Infrared Radiation Sounder (HIRS/2) radiance measurements is presented, based on knowledge of the typical statistical features of both clear and cloud contaminated radiance fields and on the application of some well known techniques for the statistical handling of data. The procedure consists of three sequential steps. In the first, the clear sky latitudinal gradient is restored using statistical correlation among HIRS/2 and MSU measurements. In the second step the scene variability (i.e. the dynamics along the longitudinal gradient) is retrieved by a discrete Fourier developments and a recursive Kalman filter. Finally, the characteristic smoothness of clear fields is introduced using a low-pass filter (third step). Applications of the whole filtering technique to measured HIRS/2 channel 5, 6 and 7 brightness temperatures are discussed and its performance is checked by comparing sets of filtered and stimulated data.

Renal formation of the vasoconstrictor prostaglandins thromboxane A "2 (TXA "2 ) and prostaglandin F "2"@a (PGF "2"@a ) was investigated in 25 patients with cardiac failure, divided into New York Heart Association functional classes I to IV, and in eight healthy control subjects. Plasma renin activity (PRA) and hemodynamic parameters were also investigated. Renal vasoconstrictor eicosanoid formation, measured in urinary daily excretion, was not different between patients in class I and control subjects. Class II to IV patients showed progressively increasing production of PGF "2"@a (F = 49.8, p < 0.001, analysis of variance) and TXA "2 (F = 37.8, p < 0.002). PGF "2"@a excretion peaked in class IV (+1266% vs class I, p < 0.001). Compared with class I, urinary excretion of thromboxane B "2 was +816% in class III and +1561% in class IV (both p < 0.001). PRA was significantly increased only in class IV (+1558%, p < 0.001). The current results indicate a progressive increase in renal production of vasoconstrictor eicosanoids directly related to New York Heart Association class and suggest that these prostanoids may have a role in deterioration of renal function. (Am Heart J 1997;133:94-100.)

The time dynamics of geoelectrical precursory time series has been investigated using autoregressive models. The approach used here allows us to obtain information on the geophysical system producing the electrical phenomena in seismic active areas when the only information about the time series comes from the time series themselves. It is based on two forecasting approaches: the global autoregressive approximation and the local autoregressive approximation. The first approach views the data as a realization of a linear stochastic process, whereas the second approach considers the data points as the results of a deterministic process, supposedly nonlinear. The comparison of the predictive skills of the two techniques is a strong test to distinguish between low-dimensional chaos and random dynamics. Our findings give us insight in the inner dynamics of the geophysical process under study: an estimate of the number of degrees of freedom of the dynamical system governing the electrical phenomena is obtained. The stochastic nature of the electrical precursory signals has been highlighted and the possible implications for the earthquake prediction problem are discussed. The processed time series are geoelectrical measurements recorded by an automatic station located in Tito (Southern Italy), which is one of the most seismic areas of the Mediterranean region. We found that the global (linear) approach is superior to the local one, and the physical system governing the phenomena of electrical nature is characterized by a large number of degrees of freedom. The results are confirmed by the presence of rich scaling properties in the power spectra of the processed electrical signals.

A procedure for forecasting and, more in general, for making statistical inference about the degree of predictability of dynamical systems given by experimental time series is presented. A parametric time series modelling approach is taken, yielding a powerful technique for analysing the structure of a given signal. The approach we propose consists in fitting autoregressive processes to the data and forecasting future values of the system on the basis of the model selected. We distinguish between two possible forecasting techniques of a dynamical system given by experimental series of observations. The «global autoregressive approximation» views the observations as a realization of a stochastic process, the autoregression coefficients are estimated by best-fitting the model to all the data at once. The «local autoregressive approximation» views the observations as realizations of a truly deterministic process and the autoregression coefficients are continuously updated by using the nearest neighbours of the current state. Then, a proper comparison between the predictive skills of the two techniques allows us to gain insight into distinguishing low-dimensional chaos from randomness. The global procedure also gives adaptive spectral filters (all-poles filters) which are able to pick the dominant oscillations of the system. As an example of the application of the procedure the author considers the Henon map and stochastic processes as well (autoregressive moving average processes). The effects of additional noise (e.g.measurement errors) are also discussed.

The dependence of Ångstrom's turbidity parameters on the wavelength has been analyzed in the wavelength interval 0.45-0.70 μm. Measurements of aerosol optical thicknesses in this range were obtained by a wide-range grating spectrometer with a resolution of ∼ 2.5 nm. Based on such measurements, two different methods for obtaining turbidity parameters have been validated and intercompared: (a) the ratio method based on processing couples of aerosol optical depths, and (b) a linear best-fitting method based on log-log plot of aerosol optical thicknesses vs. wavelength. We found that Angstr̊m's turbidity relation is quite effective in characterizing atmospheric aerosol in low-medium turbidity cases. However, the usual method of computing the turbidity parameters on the basis of a few measurements (< 10) does not produce adequate results. Accurate estimates can be only obtained using a larger number of data points

The performances of the Infrared Atmospheric Sounding Interferometer (IASI) which is under development at the aboratories of the French National Space Agency and Italian National Space Agency have been evaluated. An error analysis has been carried out on the basis of the expected radiometric noise. To this end, a linear form of the radiative transfer equation has been formulated for the direct and simultaneous estimation of temperature, water vapour and ozone profiles.

Abstract: Probes for the detection of Azospirillum strains were obtained from DNA fragments generated by random amplification of polymorphic DNA (RAPD) and tested to assess their specificity towards DNA extracted from pure cultures. The most specific probe, referred to as α4, produced a hybridization signal only with amplified DNA of A. lipoferum ATCC29731. This strain was inoculated, together with two other Azospirillum strains, in soil microcosms of different complexity and its presence tested with the probe α4. This probe confirmed its high specificity with amplified DNA extracted from the soil microcosm and in the presence of other A. lipoferum strains, indicating that the strategy for bacterial detection, based on RAPD markers, is useful for monitoring the presence of a particular strain under environment-like conditions. Other RAPD-derived probes, when tested on soil samples, did not show the same level of specificity as that shown on DNA from pure cultures. This result suggests that some precautions are necessary in the choice of a really specific RAPD marker. In a further development of this strategy, the α4 probe was sequenced and two pairs of “nested” primers were designed, which enabled a diagnostic polymerase chain reaction from soil samples that was specific for the A. lipoferum species.

In order to produce temperature or water vapour profiles from infrared radiance measurements the detection or possible cloud contamination within the field-of-view is required. In most retrieval schemes a correction phase follows so that the inversion algorithm operates on clear column infrared radiancesWe describe a new sequential objective and optimal filtering scheme aiming at processing radiances, for each infrared measuring channel, to produce a field of cloud-cleared values with sufficiently well-defined statistical properties and error structures. Basically the method uses clear measurements only and treats cloudy data as unmeasured or missing dataSimulated values of clear column radiances for HIRS/2 channel 7 are used as a test field. The results presented are retrieval of clear radiance fields from cloudy data sets, each consisting of the test field with instrumental noise added and a cloud mask defining whether each individual field of view is clear or not. Radiances defined as cloudy are consistently treated as missing data. The cloud masks used for the present exercise are obtained from the processing of real data with a very high cloud content in order to understand the behaviour and quality of the algorithm in situations close as possible to worst real cases.

A procedure to recover high resolution spectra without any intervening window from infrared Fourier spectrometer data is presented. The technique relies on the maximum entropy principle in information theory. A parametric autoregressive modelling approach is used. Numerical examples are carried using synthetic spectra computed by an high resolution radiative transfer code. The effect of additive noise is also analysed. The application of the technique to remote sensing of the atmosphere is discussed.