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Abstract Spontaneous brain activity at rest is spatially and temporally organized in networks of cortical and subcortical regions specialized for different functional domains. Even though brain networks were first studied individually through functional Magnetic Resonance Imaging, more recent studies focused on their dynamic ‘integration’. Integration depends on two fundamental properties: the structural topology of brain networks and the dynamics of functional connectivity. In this scenario, cortical hub regions, that are central regions highly connected with other areas of the brain, play a fundamental role in serving as way stations for network traffic. In this review, we focus on the functional organization of a set of hub areas that we define as the ‘dynamic core’. In the resting state, these regions dynamically interact with other regions of the brain linking multiple networks. First, we introduce and compare the statistical measures used for detecting hubs. Second, we discuss their identification based on different methods (functional Magnetic Resonance Imaging, Diffusion Weighted Imaging, Electro/Magneto Encephalography). Third, we show that the degree of interaction between these core regions and the rest of the brain varies over time, indicating that their centrality is not stationary. Moreover, alternating periods of strong and weak centrality of the core relate to periods of strong and weak global efficiency in the brain. These results indicate that information processing in the brain is not stable, but fluctuates and its temporal and spectral properties are discussed. In particular, the hypothesis of ‘ pulsed’ information processing, discovered in the slow temporal scale, is explored for signals at higher temporal resolution. Highlights • The dynamics of network integration through cortical cores is reviewed. • The statistical measures used for their definition are introduced and compared. • The degree of interaction and centrality between these hubs and the brain is dynamic. • A dynamic core architecture is presented corresponding to high global efficiency of information transfer. • These findings are linked to computational and modeling studies. [ABSTRACT FROM AUTHOR]

Abstract: In this work an Empirical Markov Chain Monte Carlo Bayesian approach to analyse fMRI data is proposed. The Bayesian framework is appealing since complex models can be adopted in the analysis both for the image and noise model. Here, the noise autocorrelation is taken into account by adopting an AutoRegressive model of order one and a versatile non-linear model is assumed for the task-related activation. Model parameters include the noise variance and autocorrelation, activation amplitudes and the hemodynamic response function parameters. These are estimated at each voxel from samples of the Posterior Distribution. Prior information is included by means of a 4D spatio-temporal model for the interaction between neighbouring voxels in space and time. The results show that this model can provide smooth estimates from low SNR data while important spatial structures in the data can be preserved. A simulation study is presented in which the accuracy and bias of the estimates are addressed. Furthermore, some results on convergence diagnostic of the adopted algorithm are presented. To validate the proposed approach a comparison of the results with those from a standard GLM analysis, spatial filtering techniques and a Variational Bayes approach is provided. This comparison shows that our approach outperforms the classical analysis and is consistent with other Bayesian techniques. This is investigated further by means of the Bayes Factors and the analysis of the residuals. The proposed approach applied to Blocked Design and Event Related datasets produced reliable maps of activation. [Copyright &y& Elsevier]

Abstract: Five clones of sour orange (Citrus aurantium L.) showing significant morphological differences were selected from our germplasm collection and characterized both by genetic and leaf volatiles analysis. The genetic studies were undertaken by the use of molecular markers developed by PCR-based techniques (ISSR and RAPD), while the leaf essential oil patterns were obtained by chromatographic and mass spectrometric determination. Data obtained suggest that reasonably similar information can be achieved from the two techniques, supporting each other in characterization studies. [Copyright &y& Elsevier]

A faecal pollution monitoring of coastal Messina waters was performed by comparing three (microscopic, enzyme, and culture) methods. Evidence of Escherichia coli cells (29.99 to 96.79% of the total enteropathogenic serotypes) retaining their viability into the marine environment was shown. β‐Glucuronidase activity rates suggested that living cells were also metabolically active. Heavily polluted sites were detected, where improperly treated urban wastes were discharged. Significant relationships between microscopic and enzymatic data proved both methods to be suitable alternatives to the culture method for E. coli detection, improving environmental quality assessment. [ABSTRACT FROM AUTHOR]

We introduce a new definition of ordered phase in a magnetic system based on properties of the local spin state probability. A statistical functional associated to this quantity depends both on amplitude and direction of the local magnetization. We show that it is possible to introduce an expansion at fixed magnetization amplitude in the inverse of lattice coordination number if the direction is selected by an extremum condition. In the limit of infinite coordination number we recover the mean field results. First order corrections are derived for the Ising model in the presence of a transverse field and for the XY model. Our results concerning critical temperature and order parameter compare favorably with other approaches. [ABSTRACT FROM AUTHOR]

We apply the dynamical mean field theory to calculate the low-density limit of the small polaron optical conductivity in the Holstein model. Classical schemes of approximation are recovered in weak coupling and in the adiabatic and antiadiabatic strong coupling limits. Such schemes are not suitable for the intermediate coupling regime, where our theory gives an anomalous behaviour of the spectral weight at low energy as the temperature decreases. [ABSTRACT FROM AUTHOR]

The brain is a dynamic system that generates a broad repertoire of perceptual, motor, and cognitive states by the integration and segregation of different functional domains represented in large-scale brain networks. However, the fundamental mechanisms underlying brain network integration remain elusive. Here, for the first time to our knowledge, we found that in the resting state the brain visits few synchronization modes defined as clusters of temporally aligned functional hubs. These modes alternate over time and their probability of switching leads to specific temporal loops among them. Notably, although each mode involves a small set of nodes, the brain integration seems highly vulnerable to a simulated attack on this temporal synchronization mechanism. In line with the hypothesis that the resting state represents a prior sculpted by the task activity, the observed synchronization modes might be interpreted as a temporal brain template needed to respond to task/environmental demands. [ABSTRACT FROM AUTHOR]

Embryo development in vivo has been studied in four Citrus aurantium L. polyembryonic genotypes. Seeds were collected 65, 85, 105, 125 and 220 days after pollination (DAP). None of the immature seeds harvested 65 and 85 DAP contained visible embryos. A single embryo at a more advanced developmental stage was observed in the central position at the micropylar apex of the embryo sac in about 74% of seeds harvested at 105 DAP, while at 125 and 220 DAP the majority of seeds had two or more embryos at the same developmental stage crowded together. Restriction fragment length polymorphism (RFLP) analysis of low- and high-copy-number nuclear DNA was used to distinguish zygotic from nucellar seedlings, Analysis of plantlets derived from in vitro culture of the bigger embryos, located in the central position at the micropylar apex of the embryo sac of seeds harvested at 105 DAP, established that the frequencies of zygotic embryos ranged from 82 to 88%. Media for immature embryo germination in vitro were based on the nutrients and vitamins of Murashige and Skoog (MS) and Murashige and Tucker (MT) media supplemented with various concentrations of sucrose and growth regulators. A total of 76% of globular stage embryos (<0.3 mm) germinated on MT medium containing 150mM sucrose and 14.4 μM gibberellic acid. Heart stage embryos (0.3 - 0.8 mm) germinated at 95% on MT medium supplemented with 150mM sucrose and 2.9 μM gibberellic acid. The addition of 500 mg/I malt extract to MS medium increased the germination of early cotyledon stage (0.8-2.0 mm) embryos to 98%. The optimum sucrose concentration for embryo rescue was 150 mM for the three embryo developmental stages. The ability to form plants in vitro strongly increased with increasing embryo developmental stage. [ABSTRACT FROM AUTHOR]

Somatic embryos were obtained from stylar tissues of three lemon plants, one of cv Lunario, one of Femminello Zagara Bianca, and one of Femminello Santa Teresa. These plants, as shown by visual observations and indexing on woody indicators, were affected by exocortis and two or more virus-like diseases such as psorosis, concave gum, impietratura and cristacortis. Two of the sources contained also mechanically transmissible viruses. Twelve 18-month-old plantlets originating from style culture-derived somatic embryos, four from each source, consistently gave negative reactions when assayed by grafting, mechanical inoculation, and serologically for the presence of viruses, virus-like agents and viroids. It was concluded that, similar to other woody species (e.g. grapevine), somatic embryogenesis opens new possibilities for the sanitary improvement of Citrus. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine cerebrospinal fluid (CSF) and serum neuron-specific enolase (NSE) concentrations in a normal population and to analyse their relationship with sex and age. The sample was recruited among patients undergoing spinal anaesthesia, without neurological diseases. NSE was determined by means of immunometric assay. One hundred and eight patients (68 men) were recruited. CSF-NSE concentration was (mean ± SD) 17.3 ± 4.6 ng/ml (men 17.4 ± 4.2, women 17.0 ± 5.2,P = 0.62); serum concentration was 8.7 ± 3.9 ng/ml (men 8.9 ± 3.9, women 8.3 ± 4.0,P = 0.06). The mean CSF/serum NSE ratio was 2.3 ± 0.8 (men 2.2 ± 0.8, women 2.4 ± 0.9,P = 0.22). In both sexes, simple regression analysis showed not significantly increasing concentrations with advancing age for both CSF and serum NSE. Serum and CSF concentrations did not correlate in both sexes. In our study, CSF-NSE was twice the serum concentration; both were not influenced by sex or age. Serum and CSF-NSE values vary widely among different studies on normal populations because of different determination methods; therefore, each laboratory should obtain its own reference values. Finally, serum NSE should be used with caution as an indicator of CSF concentration as no correlation could be demonstrated between them in our study. [ABSTRACT FROM AUTHOR]

Studies the elimination of Citrus psorosis virus (CPV) by somatic embryogenesis from stigma and style cultures. CPV detection; Loss of juvenile characters in the first year of growth; Germination of somatic embryos; Potential of somatic embryogenesis as a technique for the production of health citrus stocks.

Presents a study that investigated the frequency selection and transient dynamics in single-mode semiconductor lasers with optical feedback. Analysis of the individual switch-on events in the laser; Calculation of the steady-state spectra; Examination of the transient intensity and frequency statistics.

Abstract: The Human Connectome Project (HCP) seeks to map the structural and functional connections between network elements in the human brain. Magnetoencephalography (MEG) provides a temporally rich source of information on brain network dynamics and represents one source of functional connectivity data to be provided by the HCP. High quality MEG data will be collected from 50 twin pairs both in the resting state and during performance of motor, working memory and language tasks. These data will be available to the general community. Additionally, using the cortical parcellation scheme common to all imaging modalities, the HCP will provide processing pipelines for calculating connection matrices as a function of time and frequency. Together with structural and functional data generated using magnetic resonance imaging methods, these data represent a unique opportunity to investigate brain network connectivity in a large cohort of normal adult human subjects. The analysis pipeline software and the dynamic connectivity matrices that it generates will all be made freely available to the research community. [Copyright &y& Elsevier]

Abstract: Resting state networks (RSNs) are sets of brain regions exhibiting temporally coherent activity fluctuations in the absence of imposed task structure. RSNs have been extensively studied with fMRI in the infra-slow frequency range (nominally <10−1 Hz). The topography of fMRI RSNs reflects stationary temporal correlation over minutes. However, neuronal communication occurs on a much faster time scale, at frequencies nominally in the range of 100–102 Hz. We examined phase-shifted interactions in the delta (2–3.5Hz), theta (4–7Hz), alpha (8–12Hz) and beta (13–30Hz) frequency bands of resting-state source space MEG signals. These analyses were conducted between nodes of the dorsal attention network (DAN), one of the most robust RSNs, and between the DAN and other networks. Phase shifted interactions were mapped by the multivariate interaction measure (MIM), a measure of true interaction constructed from the maximization of imaginary coherency in the virtual channels comprised of voxel signals in source space. Non-zero-phase interactions occurred between homologous left and right hemisphere regions of the DAN in the delta and alpha frequency bands. Even stronger non-zero-phase interactions were detected between networks. Visual regions bilaterally showed phase-shifted interactions in the alpha band with regions of the DAN. Bilateral somatomotor regions interacted with DAN nodes in the beta band. These results demonstrate the existence of consistent, frequency specific phase-shifted interactions on a millisecond time scale between cortical regions within RSN as well as across RSNs. [Copyright &y& Elsevier]

Three microbial enzymatic activities involved in organic matter transformation (Leucine AminoPeptidase, LAP, β-glucosidase, β-GLU and Alkaline Phosphatase, AP) and prokaryotic abundance were studied in the Straits of Messina upwelling system. Samplings were performed monthly, between June 2003 and March 2004, at three stations with different hydrodynamic patterns. Potential hydrolysis rates were estimated using specific fluorogenic substrates. Unlike total prokaryotic abundances, quite spatially homogeneous, enzymatic values described different scenarios for each examined station. At the southern Sicilian side (Scaletta) the highest average activity rates were recorded (LAP: 72.19 ± 19.14 nmol Cleudm−3h−1, β-GLU, 12.53 ± 3.15 nmol Cgludm−3h−1, AP, 113.59 ± 35.47 nmol PO4dm−3h−1), while at the Calabrian side (Pellaro) the minimum values of LAP, β-GLU and AP were measured. Enzymatic activity values showed seasonal patterns everywhere, with summer values which were one order of magnitude higher than those recorded in other seasons and autumn values which sharply decreased. During winter, the enhanced rates of β-GLU and AP suggested the occurrence of active polysaccharide decomposition and phosphorus regeneration. The variability in the enzymatic activity patterns recorded in the Straits area was indicative of biogeochemical features differing among the examined stations; this resulted in changes in the balance between production and decomposition processes. [ABSTRACT FROM AUTHOR]

Objective: To investigate the effects of carvedilol therapy on autonomic cardiovascular regulation and baroreflex sensitivity, by short-term spectral analysis of heart rate (R-R) and systolic blood pressure (S-S) variability. Patients and Methods: The trial was conducted in 12 adults (seven men and five women, mean age 37 ± 7 years) with newly diagnosed hypertension. Patients were classified as having mild or moderate hypertension (stages I to II). R-R, S-S and respiratory signals were recorded during rest and after sympathetic activation by head-up tilt, before and after receiving a 15-day course of carvedilol (25mg once daily). Cross-spectral analysis of R-R and S-S signals was used to determine the baroreflex sensitivity index (α index). Results: At rest after carvedilol therapy, the R-R and S-S LF (low frequency) normalised units (nu) significantly decreased (p = 0.0002 and p = 0.003, respectively), while the HF (high frequency) component reciprocally increased. The R-R LF/HF ratio decreased significantly (1.28 ± 1.58 vs 0.41 ± 0.29, p = 0.008). The α index also increased significantly (12.04 ± 6.25 vs 16.05 ± 7.45, p = 0.002). During tilt, carvedilol therapy reduced the R-R and S-S LF (p = 0.0003 and 0.002, respectively), but preserved the LF increase normally induced by passive orthostatism, and significantly increased the α index (6.18 ± 1.97 vs 8.89 ± 3.29, p = 0.014). Conclusion: Our findings suggested that carvedilol attenuates cardiovascular sympathetic responsiveness and improves baroreflex sensitivity. [ABSTRACT FROM AUTHOR]