FATCHA: biometrics lends tools for CAPTCHAs

This paper presents a novel strategy to implement a CAPTCHA (Completely Automated Public Turing test to tell Computers and Humans Apart). The aim of these tests is to easily and reliably distinguish between real human users and (malicious) bots. The approach underlying FATCHA is to exploit real time capture of human actions instead of human ability to recognize visual or auditory items. The latter approach explicitly requires proposing a challenge difficult for an automatic responder but easy for a human. However, it is often the case that pursuing the first feature takes to lose the second one. Moreover the user task may be hindered by specific disabilities. According to FATCHA approach the system rather asks the user to carry out some trivial gesture, e.g., rotating or moving the head. The webcam, which is available in almost all computers or mobile devices, captures the user gesture, and the server (hosting the service to protect) matches it with the requested one. It is possible to extend the service with a second module that allows the user to authenticate himself by face recognition instead of using a password. On the contrary, FATCHA gesture challenge can be used as a liveliness test to avoid biometric spoofing. Multimodal interaction is the base for both an advanced Human Interactive Proof (HIP) test and for robust/comfortable authentication.     

Large hydrostatic piezoelectric constant and temperature dependence of the piezoelectric properties of Bi(NiTi)1/2O3: PbTiO3 ceramics

Large hydrostatic piezoelectric coefficient, d_h - 111 pC/N, for compositions in the system (1-x) Bi(NiTi)_1/2O₃: (x) PbTiO₃[BPNT] has been reported in this paper. Temperature dependencies of the dielectric, elastic, and piezoelectric properties of two compositions, x = 0.40 and x = 0.50, around the morphotropic phase boundary of Mn⁺² doped BPNT ceramics have been studied. Room temperature dielectric hysteresis loops with P_r = 37.86 μC/cm² and E_c = 25.75 kV/cm were observed for x = 0.40. Electromechanical coupling factors, k_p = 32.5%, k₃₁ = 19.7%, and k_t = 57.1% and piezoelectric constants, d₃₃ = 250 pC/N, d₃₁ = -67 pC/N, and d_h = 111 pC/N were measured in the BPNT-40 composition. The hydrophone figure of merit, d_hg_h ≈ 1055 × 10^-15 m²/N was calculated from these measurements.     

Controlled and automatic processing during animal word list generation in schizophrenia.

Controlled and automatic aspects of semantic-associative functioning in schizophrenia were investigated by evaluating performance on animal word list generation (WLG). Responses from control (n?=?47) and patient (n?=?38) participants were subjected to multidimensional scaling (MDS), cluster analysis (CA), and indices on the basis of number of shared attributes (SA) between consecutive responses. Patient MDS results accounted for less variance and contained more error than control data. CA results yielded fewer and less clear animal-response subgroups among patients yet demonstrated intact associations among strongly related exemplars. The SA indices revealed better clustering and more effective switching among response clusters in controls than patients. Results suggest that animal WLG in schizophrenia is compromised both by aberrant automatic semantic-associative network activation and by controlled processes such as search, access, and selection. This pattern is consistent with prominent frontotemporal pathology evident in the disorder. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Wheat quality in organic and conventional farming: results of a 21 year field experiment

Consumers have become more aware of healthy and safe food produced with low environmental impact. Organic agriculture is of particular interest in this respect, as manifested by 5.768 million hectares managed pursuant to Council Regulation (EEC) 2092/91 in Europe. However, there can be a considerable risk that the avoidance of chemical inputs in organic farming will result in poor food quality. Here the results of a study on the quality of wheat (Triticum aestivum L.) grown in a 21 year agrosystem comparison between organic and conventional farming in central Europe are reported. Wheat was grown in a ley (grass/clover) rotation. The 71% lower addition of plant‐available nitrogen and the reduced input of other means of production to the organic field plots led to 14% lower wheat yields. However, nutritional value (protein content, amino acid composition and mineral and trace element contents) and baking quality were not affected by the farming systems. Despite exclusion of fungicides from the organic production systems, the quantities of mycotoxins detected in wheat grains were low in all systems and did not differ. In food preference tests, as an integrative method, rats significantly preferred organically over conventionally produced wheat. The findings indicate that high wheat quality in organic farming is achievable by lower inputs, thereby safeguarding natural resources. Copyright © 2007 Society of Chemical Industry     

Towards object-oriented modelling of euclidean geometry

This paper presents an object-oriented approach to interactive modelling of geometric objects. The objects are specified by geometric constructions that are built by mimicing the compass-and-ruler manual approach in a direct manipulation graphical interface. The system adopts a programming-by-example paradigm to enrich construction methods incrementally. New constructions can be used to define new classes of objects or new methods for an existing class. Messages exchanged among objects specify geometric relationships among entities. Messages sent at construction time implicitly form a relationship network, which is preserved during subsequent geometric transformations, so that geometric constraints can be satisfied without resorting to numerical methods. The prototype GEObject is implemented under Actor in a Windows 3.0 environment.     

Activation of ErbB2 during wallerian degeneration of sciatic nerve

We used anti-phosphopeptide-immunodetecting antibodies as immunohistochemical reagents to define the location and activity state of p185(erbB2) during Wallerian degeneration. Nerve damage induces a phosphorylation event at Y1248, a site that couples p185(erbB2) to the Ras-Raf-MAP kinase signal transduction pathway. Phosphorylation of p185(erbB2) occurs within Schwann cells and coincides in time and space with Schwann cell mitotic activity, as measured by bromodeoxyuridine uptake. These visual images of receptor autophosphorylation link activation of p185(erbB2) to the Schwann cell proliferation that accompanies nerve regeneration.     

Moral development and politics a decade later: A replication and extension.

Previous investigations performed during the age of student protest indicated a curvilinear relationship between moral development and political ideology and behavior, with both higher and lower levels of moral reasoning associated with leftist inclinations. The present research determined if the linkage between moral reasoning level and political choice could be extended to former students negotiating their middle adulthood during a period of political quiescence. Consistent with the expectations of N. Haan et al (1968), data obtained from 76 persons who had been students at the University of California at Berkeley in 1964 suggest a linear relationship between moral judgment and leftist politics, with premoral reasoners no longer overrepresented among either liberal or politically active Ss. Previous investigators' substantive and directional interpretations of the relationship between moral maturity and political preference are weighed against recent challenges to the purportedly primary, structural, and value-free basis of the L. Kohlberg (1969) model of moral development. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Determination of diffusion coefficients of glycerol and glucose from starch based thermoplastic compounds on simulated physiological solution

Blends of corn starch with poly(ethylene-vinylalcohol) copolymer (SEVA-C) have been studied and reported as biodegradable. These materials are known to be sensitive to enzymatic action, evidencing a degradation of the starch phase in -amylase assays. However, from the physical-chemical point of view the degradation of the blend is mainly associated with the leaching of glycerol, since other compounds are not released and no carbohydrates were found in the degradation solution. Based on these results, the present work attempts to determinate the respective diffusion coefficients. Four different experiments were performed, using samples with different thicknesses that were immersed in a simulated physiological solution. High performance liquid chromatography (HPLC) was used to separate the sugar derivatives and glycerol from the degradation solutions. The obtained data were fitted to an empirical model to allow the estimation of the diffusion coefficient for glycerol and glucose, based on the analytical solution for Ficks law of diffusion, and a good agreement was found (R² 1). The glycerol leaches quickly out during the first few days of immersion, stabilizing thereafter, presenting greater diffusion coefficients for thicker samples. As the quantity of saccharides in the solution remains almost invariable along the experiments, this work also confirms that the degradation process is difficult without the action of enzymes.