AUTHENTIC EVALUATION OF COMPETENCE

Describe competence is a problematic operation that depends on the context and, at school, on the disciplinary character involved. It is believed that the competence is inherent to individual and that this represents his knowledge, experiences and abilities (Le Boterf, 1992). According to social constructivist model, competence refers to the subject intimate mental processes, that allow to break a critical situation and then implement original strategies for solution. McClelland (1973) to whom is attributed the authorship of word, believes that the competence needs motivation , occurs in a context and is achieved by means of appropriate behaviors. Particularly at school, active teaching strategies using the competence to indicate the student’s ability to independently solve a problem, deploying their knowledge in practice (Pellerey, 2004). To assess the competence you need to design tests of authentic assessment that encourage students to active their knowledge to solve complex tasks

Firm Opacity Lies in the Eye of the Beholder

We classify and test empirical measures of firm opacity and document theoretical and empirical inconsistencies across these proxies by testing the relative opacity of banks versus non-banks. We evaluate the effectiveness of these proxies by observing the effect of two cleanly identified shocks to firm-specific information: credit rating initiation and inclusion in the S&P 500 index. Using a difference-in-difference approach, we compare firms that are newly rated and firms that are included in the S&P 500 index with a propensity matched sample of “unchanged” firms. We find that only the number of analysts and Amihud's illiquidity ratio provide consistent patterns across different estimation specifications and different econometric settings. These two proxies show that banks are more opaque than non-banks. Based on our tests, we recommend that these proxies be used as the primary measures of firm opacity

Surface doping in T6/ PDI-8CN2 Heterostructures investigated by transport and photoemission measurements

In this paper, we discuss the surface doping in sexithiophene (T6) organic field-effect transistors by PDI-8CN2. We show that an accumulation heterojunction is formed at the interface between the organic semiconductors and that the consequent band bending in T6 caused by PDI-8CN2 deposition can be addressed as the cause of the surface doping in T6 transistors. Several evidences of this phenomenon have been furnished both by electrical transport and photoemission measurements, namely the increase in the conductivity, the shift of the threshold voltage and the shift of the T6 HOMO peak towards higher binding energies.Comment: 5 pages, 5 figure

A simple and quick method for loading proteins in extracellular vesicles

Extracellular vesicles (EVs) mediate intercellular transport of biomolecular cargo in the body, making them promising delivery vehicles for bioactive compounds. Genetic engineering of producer cells has enabled encapsulation of therapeutic proteins in EVs. However, genetic engineering approaches can be expensive, time-consuming, and incompatible with certain EV sources, such as human plasma and bovine milk. The goal of this study was to develop a quick, versatile, and simple method for loading proteins in EVs post-isolation. Proteins, including CRISPR associated protein 9 (Cas9), were bound to cationic lipids that were further complexed with MDA-MB-231 cell-derived EVs through passive incubation. Size-exclusion chromatography was used to remove components that were not complexed with EVs. The ability of EVs to mediate intracellular delivery of proteins was compared to conventional methods, such as electroporation and commercial protein transfection reagents. The results indicate that EVs retain native features following protein-loading and obtain similar levels of intracellular protein delivery as conventional methods, but display less toxicity. This method opens up opportunities for rapid exploration of EVs for protein delivery

Emulation with Organic Memristive Devices of Impairment of LTP Mechanism in Neurodegenerative Disease Pathology

© 2017 Silvia Battistoni et al. We explore and demonstrate the extension of the synapse-mimicking properties of memristive devices to a dysfunctional synapse as it occurs in the Alzheimer's disease (AD) pathology. The ability of memristive devices to reproduce synapse properties such as LTP, LTD, and STDP has been already widely demonstrated, and moreover, they were used for developing artificial neuron networks (perceptrons) able to simulate the information transmission in a cell network. However, a major progress would be to extend the common sense of neuromorphic device even to the case of dysfunction of natural synapses. Can memristors efficiently simulate them? We provide here evidences of the ability of emulating the dysfunctional synaptic behavior typical of the AD pathology with organic memristive devices considering the effect of the disease not only on a single synapse but also in the case of a neural network, composed by numerous synapses

Optimizing picene molecular assembling by supersonic molecular beam deposition

Here we report an investigation of the growth of picene by supersonic molecular beam deposition on thermal silicon oxide and on a self-assembled monolayer of hexamethyldisiloxane (HMDS). In both cases film morphology shows a structure with very sharp island edges and well-separated islands which size and height depend on the deposition conditions. Picene films growth on bare silicon covered with hydrophobic HDMS shows islands characterized by large regular crystallites of several micrometers; on the other hand, films growth on silicon oxide shows smaller and thicker islands. We analyzed the details of the growth model and describe it as a balancing mechanism involving the weak interaction between molecules and surface and the strong picene-picene interaction that leads to a different Schwoebel-Ehrlich barrier in the first layer with respect to the successive one. Finally, we study the charge transport properties of these films by fabricating field-effect transistors devices in both top and bottom contact configuration. We notice that substrate influences the electrical properties of the device and we obtained a maximum mobility value of 1.2 cm2 V-1 s-1 measured on top contact devices in air. © 2012 American Chemical Society

PEDOT:PSS Morphostructure and ion-to-electron transduction and amplification mechanisms in organic electrochemical transistors

Organic electrochemical transistors (OECTs) represent a powerful and versatile type of organic-based device, widely used in biosensing and bioelectronics due to potential advantages in terms of cost, sensitivity, and system integration. The benchmark organic semiconductor they are based on is poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), the electrical properties of which are reported to be strongly dependent on film morphology and structure. In particular, the literature demonstrates that film processing induces morphostructural changes in terms of conformational rearrangements in the PEDOT:PSS in-plane phase segregation and out-of-plane vertical separation between adjacent PEDOT-rich domains. Here, taking into account these indications, we show the thickness-dependent operation of OECTs, contextualizing it in terms of the role played by PEDOT:PSS film thickness in promoting film microstructure tuning upon controlled-atmosphere long-lasting thermal annealing (LTA). To do this, we compared the LTA-OECT response to that of OECTs with comparable channel thicknesses that were exposed to a rapid thermal annealing (RTA). We show that the LTA process on thicker films provided OECTs with an enhanced amplification capability. Conversely, on lower thicknesses, the LTA process induced a higher charge carrier modulation when the device was operated in sensing mode. The provided experimental characterization also shows how to optimize the OECT response by combining the control of the microstructure via solution processing and the effect of postdeposition processing

Nanomolar detection of the antitumor drug tamoxifen by flexible organic electrochemical devices

Organic Electrochemical Transistors (OECTs) represent a versatile tool successfully exploited in the field of Bioelectronics. In particular, OECTs have been used for the detection of a wide set of bioanalytes, often showing superior performance compared to that of commonly used sensors. In this study, we propose a flexible, disposable OECT, based on poly (3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) channels and few layers graphene (FLG) sheets gate electrodes, for the detection of Tamoxifen (TAM), an important antitumor drug widely used in breast cancer therapy. The optimal device operation conditions in terms of sensitivity and limit of detection (LOD) have been investigated too

Communication for Cultural Integration : The Case of a Secondary Reception Centre

The language, a human species-specific activity, permits of knowing, organizing and recounting the reality that around us. Although the vocal level represents the preferred channel of expression, everyday experiences are shared in many ways in the community. Facial expressions, gestures, but in general, our action are reflection of the culture that has shaped us. In this paper, the authors report some considerations about the typical communication dynamics of a Secondary Reception Centre, in the context of the province of Avellino (Italy). The descriptive observation realised in the fieldwork, shows that a designed and oriented educational communication looks after of the distinctive characteristics of each. Consequently, a reflection on the individual and collective communication practices could allow overcoming the mere reception and predicting a real introduction into the social substratum of the Host Country