A bottom–up model of spatial attention predicts human error patterns in rapid scene recognition

Humans demonstrate a peculiar ability to detect complex targets in rapidly presented natural scenes. Recent studies suggest that (nearly) no focal attention is required for overall performance in such tasks. Little is known, however, of how detection performance varies from trial to trial and which stages in the processing hierarchy limit performance: bottom–up visual processing (attentional selection and/or recognition) or top–down factors (e.g., decision-making, memory, or alertness fluctuations)? To investigate the relative contribution of these factors, eight human observers performed an animal detection task in natural scenes presented at 20 Hz. Trial-by-trial performance was highly consistent across observers, far exceeding the prediction of independent errors. This consistency demonstrates that performance is not primarily limited by idiosyncratic factors but by visual processing. Two statistical stimulus properties, contrast variation in the target image and the information-theoretical measure of “surprise” in adjacent images, predict performance on a trial-by-trial basis. These measures are tightly related to spatial attention, demonstrating that spatial attention and rapid target detection share common mechanisms. To isolate the causal contribution of the surprise measure, eight additional observers performed the animal detection task in sequences that were reordered versions of those all subjects had correctly recognized in the first experiment. Reordering increased surprise before and/or after the target while keeping the target and distractors themselves unchanged. Surprise enhancement impaired target detection in all observers. Consequently, and contrary to several previously published findings, our results demonstrate that attentional limitations, rather than target recognition alone, affect the detection of targets in rapidly presented visual sequences

Assessing and countering reaction attacks against post-quantum public-key cryptosystems based on QC-LDPC codes

Code-based public-key cryptosystems based on QC-LDPC and QC-MDPC codes are promising post-quantum candidates to replace quantum vulnerable classical alternatives. However, a new type of attacks based on Bob's reactions have recently been introduced and appear to significantly reduce the length of the life of any keypair used in these systems. In this paper we estimate the complexity of all known reaction attacks against QC-LDPC and QC-MDPC code-based variants of the McEliece cryptosystem. We also show how the structure of the secret key and, in particular, the secret code rate affect the complexity of these attacks. It follows from our results that QC-LDPC code-based systems can indeed withstand reaction attacks, on condition that some specific decoding algorithms are used and the secret code has a sufficiently high rate.Comment: 21 pages, 2 figures, to be presented at CANS 201

Local detection of enzymatic ion generation with polycrystalline silicon interdigitated electrodes and its application to biosensing

Chips containing polycrystalline silicon interdigitated electrodes are modified with the enzyme urease. The sensors are able to detect changes in the resitivity of the solution near their surface, where the enzymatic reaction generates charged species. The electrodes are also grafted with an antigen and queried with different amounts of urease labeled antibody. The response of the modified electrodes is proportional to the amount of enzyme attached to the surface by the biorecognition event, thus validating the assay for biosensing applications

Aquaculture production and use of insects for feed: a consumer perspective

Worldwide, aquaculture is assuming ever more importance in diminishing the pressure on wild stocks in the seas. Prices of feed used in farming fish are increasing, due the rise in demand. Research on sustainable sources of feed was recently intensified and insects as meal to substitute soybean and fish meals and oils seems a promising field. Consequently we explored future consumer attitude toward the consumption of fish farmed on insect meals, as a mean of enhancing the sustainability of the farming system in aquaculture. We focused our attention on Italian consumers of fish and the results show a sensitive consumer, willing to try an innovative product, interested in research to improve the safe-guarding of marine resources

Aquaculture production and use of insects for feed: a consumer perspective

Worldwide, aquaculture is assuming ever more importance in diminishing the pressure on wild stocks in the seas. Prices of feed used in farming fish are increasing, due the rise in demand. Research on sustainable sources of feed was recently intensified and insects as meal to substitute soybean and fish meals and oils seems a promising field. Consequently we explored future consumer attitude toward the consumption of fish farmed on insect meals, as a mean of enhancing the sustainability of the farming system in aquaculture. We focused our attention on Italian consumers of fish and the results show a sensitive consumer, willing to try an innovative product, interested in research to improve the safe-guarding of marine resources

LEDAkem: a post-quantum key encapsulation mechanism based on QC-LDPC codes

This work presents a new code-based key encapsulation mechanism (KEM) called LEDAkem. It is built on the Niederreiter cryptosystem and relies on quasi-cyclic low-density parity-check codes as secret codes, providing high decoding speeds and compact keypairs. LEDAkem uses ephemeral keys to foil known statistical attacks, and takes advantage of a new decoding algorithm that provides faster decoding than the classical bit-flipping decoder commonly adopted in this kind of systems. The main attacks against LEDAkem are investigated, taking into account quantum speedups. Some instances of LEDAkem are designed to achieve different security levels against classical and quantum computers. Some performance figures obtained through an efficient C99 implementation of LEDAkem are provided.Comment: 21 pages, 3 table

Analysis of reaction and timing attacks against cryptosystems based on sparse parity-check codes

In this paper we study reaction and timing attacks against cryptosystems based on sparse parity-check codes, which encompass low-density parity-check (LDPC) codes and moderate-density parity-check (MDPC) codes. We show that the feasibility of these attacks is not strictly associated to the quasi-cyclic (QC) structure of the code but is related to the intrinsically probabilistic decoding of any sparse parity-check code. So, these attacks not only work against QC codes, but can be generalized to broader classes of codes. We provide a novel algorithm that, in the case of a QC code, allows recovering a larger amount of information than that retrievable through existing attacks and we use this algorithm to characterize new side-channel information leakages. We devise a theoretical model for the decoder that describes and justifies our results. Numerical simulations are provided that confirm the effectiveness of our approach

Long-term disease-free survival of patients with radically resected thymomas: relevance of cell-cycle protein expression

BACKGROUND. Despite radical Surgical resection, thymomas often recur. The objective of the current retrospective Study was to investigate the prognostic relevance of the expression of cell-cycle proteins in these neoplasms to formulate a possible therapeutic Surveillance strategy for the prevention of recurrence. METHODS. The authors retrospectively reviewed the main clinicopathologic factors, including the World Health Organization (WHO) classification, of patients with thymoma who had undergone radical surgical resection. Specimens were studied using immunohistochemistry and the expression of cell-cycle proteins (i.e., p21, p27, and p53) was assessed. Univariate and multivariate analysis of predicting survival prognostic factors were performed. RESULTS. The authors analyzed 88 patients with thymoma who underwent radical surgical resection at the study institution. According to the Masaoka staging system, 41 patients had Stage I disease, 31 patients had Stage II disease, and 16 patients had Stage III disease. There were 24 tumor recurrences (27.3%), 4 of which were local, 16 of which were distant intrathoracic, and 4 of which were extrathoracic. The second radical resection provided a disease-free Survival rate that was similar to the first. Only Masaoka stage (P=0.001), WHO classification (P=0.001), high expression of p53 (P=0.03), and low expression of p21 (P=0.02) and p27 (P=0.001) were found to he correlated with a reduced disease-free survival. Low p27 expression was found to be the most significant predictive factor of a short disease-free Survival (P=0.001), especially when associated with low p21 expression and high p53 expression (P=0.0001). CONCLUSIONS. Long-term disease-free survival in thymoma patients treated with radical surgical resection Was found to be correlated with Masaoka stage, WHO classification, and expression of cell-cycle proteins, with the latter found to be the most significant predictive factor. Functional cooperation between cell-cycle proteins might constitute another level of regulation in tumor growth. More careful surveillance should be adopted whenever there is negative cell-cycle protein expression. (c) 2005 American Cancer Society

Glass reflow on 3-dimensional micro-apertures for electrophysiological measurements on-chip

We propose a new method to fabricate micro-apertures for on-chip electrophysiological measurements of living cells. Thermal reflow of phosphosilicate glass (PSG) is applied to funnel- or nozzle-type microstructures to generate very smooth surfaces on the finalized chip. Such 3-dimensional microstructures show close similarities to fire-polished glass pipette tips. Immobilized cells fit perfectly to these structures offering a large contact area for sealing between the cell membrane and the oxide surface. A tight cell/chip-aperture seal is an important requirement for the present application. We demonstrate the formation of stable gigaseals with Chinese hamster ovary (CHO) cells for both types of microstructures without the need of any post-fabrication surface treatment. By adjusting the PSG reflow parameters, the shape of the apertures can be modified and diameters down to the sub-micrometer range may be achieved. The application of PSG reflow to MEMS fabrication is an interesting new option to create unconventional microstructure