Direct and Indirect Complementarity between Workplace Reorganization and New Technology

We link survey and balance sheet data to investigate the extent of complementarity between the introduction of new technology and changes in workplace practices. Across all firms, we find that new technology is complementary with higher work intensity. Similarly, changes in work techniques yield diffuse complementarity gains, particularly in firms undergoing extensive restructuring. Changes in work organization yield, on average, complementarity gains in terms of productivity growth. Substitutability between new technology and specific workplace changes is sometimes found, consistently with the presence of costs associated to learning functions or resistance to changes.workplace practices, ICT investments, complementarity.

Interazione acido umico-metalli pesanti in un suolo boschivo

Analytical data on the heavy metal content of humic acid extracted from the surface soil samples of a wooded area in southern Sardinia and correlations between soil and humic acid metal content are reported. A tentative approach to the determination of humic acid-heavy metal complex stability constants, based upon Langmuir's isotherm is proposed

Raro caso de tumores adenomatoides múltiples derivados de la túnica vaginal de testículo y epidídimo

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Hardware design of LIF with Latency neuron model with memristive STDP synapses

In this paper, the hardware implementation of a neuromorphic system is presented. This system is composed of a Leaky Integrate-and-Fire with Latency (LIFL) neuron and a Spike-Timing Dependent Plasticity (STDP) synapse. LIFL neuron model allows to encode more information than the common Integrate-and-Fire models, typically considered for neuromorphic implementations. In our system LIFL neuron is implemented using CMOS circuits while memristor is used for the implementation of the STDP synapse. A description of the entire circuit is provided. Finally, the capabilities of the proposed architecture have been evaluated by simulating a motif composed of three neurons and two synapses. The simulation results confirm the validity of the proposed system and its suitability for the design of more complex spiking neural network

Towards Neuro-Inspired Electronic Oscillators Based on The Dynamical Relaying Mechanism

Electronic oscillators are used for the generation of both continuous and discrete signals, playing a fundamental role in today’s electronics. In both contexts, these systems require stringent performances such as spectral purity, low phase noise, frequency and temperature stability. In state of the art oscillators the preservation of some of these aspects is jeopardized by specific critical issues, e.g., the sensitivity to load capacitance or the component aging over time. This leaves room for the search of new technologies for their realization. On the other hand, in the last decade electronics has been influenced by a growing number of neuro-inspired mechanisms, which allowed for alternative techniques aimed at solving some classical critical issues.In this paper we present an exploratory study for the development of electronic oscillators based on the neuro-inspired mechanism dynamical relaying, which relies on a structure composed of three delay coupled units (as neurons or even neuron populations) able to resonate and self-organise to generate and maintain a given rhythm with great reliability over a considerable parameter range, showing robustness to noise. We used the recent leaky integrated and fire with latency (LIFL) as neuron model. We have initially developed the mathematical model of the neuro-inspired oscillator, and implemented it using Matlab®; then, we have realized the schematic of such system in PSpice®. Finally, the model has been validated to verify whether it observes the fundamental properties of the dynamical relaying mechanisms described in computational neuroscience studies, and if the circuit implementation presents the same behaviour of the mathematical model.Validation results suggest that the dynamical relaying mechanism can be proficuously taken in consideration as alternative strategy for the design of electronic oscillators

Impatto ambientale dell'attività mineraria in Sardegna: studi mineralogici e geochimici

Sardinia is characterized by a large variety of geologic and hydrologic environments, and by a rich wealth of mineral resources, that fueled a millennial history of mining activity. Therefore, it provides an excellent ground for studies of the environmental impact of mining activity. In this communication, we summarize the results of our studies, specifically concerning the deposits of Baccu Locci (polymetallic�Pb,As), Furtei (epithermal Au), Monteponi (Pb-Zn-Ag), and Montevecchio (Pb-Zn-Ag). In abandoned mining districts (Baccu Locci, Monteponi, and Montevecchio), because of a poor management of environmental issues, we observe significant heavy metal contamination. On the other hand, in the active Furtei mine the first four years of exploitation did not cause remarkable changes with respect to pre-mining baseline conditions

Characterization of circulating blood dendritic cell subsets DC123+ (lymphoid) and DC11C+ (myeloid) in prostate adenocarcinoma patients

PURPOSE. We verified whether prostate adenocarcinoma produces specific modifications in DC subsets count. METHODS. Twenty-one untreated prostate adenocarcinomas were divided on the basis of clinical stage in localized and metastatic disease. As control we used a population of 18 healthy male subjects. For DCs enumeration, peripheral blood (PB) samples were obtained in all cases. A single-platform flow cytometric assay based on Tru-COUNT was used for the enumeration of the two DCs subsets, myeloid (mDCs) and plasmacytoid (pDCs). RESULTS. We showed a statistically significant reduction in pDCs count in prostate cancer population when compared to healthy controls (P = 0.002). Comparing each clinical stage with healthy controls, significant differences were found between controls and the metastatic group in both pDCs and mDCs (P = 0.005 and P = 0.023 respectively) but not between controls and the localized group (P = 0.055 and P = 0.829 respectively). CONCLUSIONS. We showed that DCs count in PB is significantly affected by prostate adenocarcinoma progression in a metastatic disease. © 2006 Wiley-Liss, Inc

towards neuro inspired electronic oscillators based on the dynamical relaying mechanism

Electronic oscillators are used for the generation of both continuous and discrete signals, playing a fundamental role in today's electronics. In both contexts, these systems require stringent performances such as spectral purity, low phase noise, frequency and temperature stability. In state of the art oscillators the preservation of some of these aspects is jeopardized by specific critical issues, e.g., the sensitivity to load capacitance or the component aging over time. This leaves room for the search of new technologies for their realization. On the other hand, in the last decade electronics has been influenced by a growing number of neuro-inspired mechanisms, which allowed for alternative techniques aimed at solving some classical critical issues. In this paper we present an exploratory study for the development of electronic oscillators based on the neuro-inspired mechanism dynamical relaying , which relies on a structure composed of three delay coupled units (as neurons or even neuron populations) able to resonate and self-organise to generate and maintain a given rhythm with great reliability over a considerable parameter range, showing robustness to noise . We used the recent leaky integrated and fire with latency (LIFL) as neuron model. We have initially developed the mathematical model of the neuro-inspired oscillator , and implemented it using Matlab®; then, we have realized the schematic of such system in PSpice®. Finally, the model has been validated to verify whether it observes the fundamental properties of the dynamical relaying mechanisms described in computational neuroscience studies, and if the circuit implementation presents the same behaviour of the mathematical model. Validation results suggest that the dynamical relaying mechanism can be proficuously taken in consideration as alternative strategy for the design of electronic oscillators

Continuous-time spiking neural networks: paradigm and case studies

In the last decades many neuron models have been proposed in order to emulate the spiking behavior of the cortical neurons, from the simplest Integrateand- Fire to the most bio-realistic Hodgkin-Huxley model. The choice of which model have to be used depends on the trade-off between bio-plausibility and computational cost, that may be related to the specific purpose. The modeling of a continuous-time spiking neural network is the main purpose of this thesis. The “continuous-time” term refers to the fact that a spike can occur at any given time, thus in order to do exact computations without loss of information an exact ad hoc event-driven strategy for simulations has been implemented. In particular, the latter is suitable for the simplified neuron model here used. Despite its simplicity, the model shows some important bio-plausible behaviors, such as subthreshold decay, spike latency, refractoriness, etc. Moreover, some bio-inspired synaptic plasticity rules have been implemented (e.g., STDP). With the aim of taking into account non-local interconnections among populations of neurons, gammadistributed synaptic delays are also introduced. These characteristics make possible to investigate various scenarios in which the dynamics showed by the network can be more bio-realistic. Further, some case studies are illustrated: jitter phenomenon and “path multimodality” in feedforward networks, and dynamical activity groups for CNN-like topologies. Finally, future directions of this work are briefly discussed