Binary Biometrics: An Analytic Framework to Estimate the Bit Error Probability under Gaussian Assumption

In recent years the protection of biometric data has gained increased interest from the scientific community. Methods such as the helper data system, fuzzy extractors, fuzzy vault and cancellable biometrics have been proposed for protecting biometric data. Most of these methods use cryptographic primitives and require a binary representation from the real-valued biometric data. Hence, the similarity of biometric samples is measured in terms of the Hamming distance between the binary vector obtained at the enrolment and verification phase. The number of errors depends on the expected error probability Pe of each bit between two biometric samples of the same subject. In this paper we introduce a framework for analytically estimating Pe under the assumption that the within-and between-class distribution can be modeled by a Gaussian distribution. We present the analytic expression of Pe as a function of the number of samples used at the enrolment (Ne) and verification (Nv) phases. The analytic expressions are validated using the FRGC v2 and FVC2000 biometric databases

A 19-channel d.c. SQUID magnetometer system for brain research

A 19-channel d.c. SQUID magnetometer system for neuromagnetic investigations is under constuction. The first-order gradiometers for sensing the signal are placed in a hexagonal configuration. D.c. SQUIDs based on niobium/aluminium technology have been developed, leading to a field sensitivity of about 5 fT/ Hz. SQUID read-out is realized with a resonant transformer circuit at 100 kHz. The multichannel control and detection electronics are compactly built

Transfer of photosynthetic products in gelatinous colonies of Phaeocystis pouchetii (Haptophyceae) and its effect on the measurement of excretion rate

Colonies of the alga Phaeocystispouchetj~ (average colony diameter ca 4 mm) were subjected to light/dark periods in culture, and production and consumption of macromolecules of the colony matrix were measured. In the light, up to ca 32 % of the total photosynthetic carbon fixation, consisting mostly of large-molecular-weight products (MW > 1800), were accumulated in the colonial matrix. In the dark, these macromolecular compounds disappeared, whereas monomeric and oligomeric compounds were found, suggesting reassimilation of colonial substances by P. pouchetii cells. Stepw~se filtration allowed separate analysis of cells, colonial matrix and surrounding medium. The latter 2 compartments differed widely in size spectra of organic compounds (as determined by gel-permeation) and in fluctuations over a light/dark cycle, suggesting that the very high rates of carbon excretion during P. pouchetii blooms in previous reports should be reconsidered

Structure of the Cytoplasmic Loop between Putative Helices II and III of the Mannitol Permease of Escherichia coli: A Tryptophan and 5-Fluorotryptophan Spectroscopy Study

In this work, four single tryptophan (Trp) mutants of the dimeric mannitol transporter of Escherichia coli, EIImtl, are characterized using Trp and 5-fluoroTrp (5-FTrp) fluorescence spectroscopy. The four positions, 97, 114, 126, and 133, are located in a region shown by recent studies to be involved in the mannitol translocation process. To spectroscopically distinguish between the Trp positions in each subunit of dimeric EIImtl, 5-FTrp was biosynthetically incorporated because of its much simpler photophysics compared to those of Trp. The steady-state and time-resolved fluorescence methodologies used point out that all four positions are in structured environments, both in the absence and in the presence of a saturating concentration of mannitol. The fluorescence decay of all 5-FTrp-containing mutants was highly homogeneous, suggesting similar microenvironments for both probes per dimer. However, Stern-Volmer quenching experiments using potassium iodide indicate different solvent accessibilities for the two probes at positions 97 and 133. A 5 Å two-dimensional (2D) projection map of the membrane-embedded IICmtl dimer showing 2-fold symmetry is available. The results of this work are in better agreement with a 7 Å projection map from a single 2D crystal on which no symmetry was imposed.

G protein-coupled receptors are dynamic regulators of digestion and targets for digestive diseases

G protein-coupled receptors (GPCRs) are the largest family of transmembrane signaling proteins. Within the gastrointestinal tract, GPCRs expressed by epithelial cells sense contents of the lumen, and GPCRs expressed by epithelial cells, myocytes, neurons, and immune cells participate in communication amongst cells. GPCRs control digestion, mediate digestive diseases, and coordinate repair and growth. GPCRs are the target of over one third of therapeutic drugs, including many drugs used to treat digestive diseases. Recent advances in structural, chemical, and cell biology research have revealed that GPCRs are not static binary switches that operate from the plasma membrane to control a defined set of intracellular signals. Rather, GPCRs are dynamic signaling proteins that adopt distinct conformations and subcellular distributions when associated with different ligands and intracellular effectors. An understanding of the dynamic nature of GPCRs has provided insights into the mechanism of activation and signaling of GPCRs, and has revealed opportunities for drug discovery. We review the allosteric modulation, biased agonism, oligomerization, and compartmentalized signaling of GPCRs that control digestion and digestive diseases. We highlight the implications of these concepts for the development of selective and effective drugs to treat diseases of the gastrointestinal tract

The Higgs Mass as the Discriminator of Electroweak Models

In the Minimal Supersymmetric Model (MSSM) and the Next to Minimal Supersymmetric Model [(M+1)SSM], an upper bound on the lightest higgs mass can be calculated. On the other hand, vacuum stability implies a lower limit on the mass of the higgs boson in the Standard Model (SM). We find that a gap exists for $m_t \stackrel{>}{\sim} 165$ GeV between the SM and both the MSSM and the (M+1)SSM bounds. Thus, if the new top quark mass measurement by CDF remains valid, a first measurement of the higgs mass will serve to exclude either the SM or the MSSM/(M+1)SSM higgs sectors. In addition, we discuss Supersymmetric Grand Unified Theories, other extentions of the SM, the discovery potential of the lightest higgs, and the assumptions on which our conclusions are based.Comment: 9 pages, 2 figures, VAND-TH-94-1

Paclitaxel, ifosfamide and cisplatin with granulocyte colony-stimulating factor or recombinant human interleukin 3 and granulocyte colony-stimulating factor in ovarian cancer: a feasibility study.

The tolerability and efficacy of four courses of paclitaxel and ifosfamide plus cisplatin every 3 weeks was evaluated in patients with residual or refractory ovarian cancer. Additionally, supportive haematological effects of recombinant human interleukin 3 (rhIL-3) and recombinant human granulocyte colony-stimulating factor (G-CSF) were studied. Paclitaxel starting dose was 135 mg m(-2) (day 1), with ifosfamide dose 1.2 g m(-2) day(-1) (days 2-4) and cisplatin dose 30 mg m(-2) day(-1) (days 2-4). All 16 patients received 5.0 microg kg(-1) day(-1) G-CSF (days 7-16) and, in addition, eight patients were randomized to receive 10 microg kg(-1) day(-1) rhIL-3 (days 5-9). Paclitaxel and ifosfamide doses were reduced when grade IV haematological toxicity occurred. In the absence of grade IV haematological toxicity and normal recovery of haematopoiesis, paclitaxel dose was escalated. Toxicity was evaluable in 56 courses, with haematological effects in 52. Despite antiemetic treatment, nausea and vomiting (> or = grade I) occurred in 50 courses. Five patients had persisting peripheral neuropathy. Renal and liver function were not affected. Grade IV neutropenia occurred in 12 out of 52 courses, with neutropenic fever in two patients, both of whom died from fatal septicaemia. Grade IV thrombocytopenia without bleeding was observed in 15 courses. Grade IV haematological toxicity was associated with hepatic metastases and concurrent increases in alkaline phosphatase (P <0.001) and gamma-glutamyltransferase (P=0.007). No relation was found between haematological toxicity and pharmacokinetic parameters of paclitaxel. Patients treated with rhIL-3 showed a tendency to a faster platelet recovery (not affecting platelet nadir), and the cisplatin dose intensity was higher (P=0.025). Six of the nine evaluable patients had a tumour response. The overall median progression-free survival was 7 months and the overall mean survival was 13 months. In conclusion, this potentially interesting combination as second-line treatment showed a low tolerability with unexpected mortality, while rhIL-3 administration tended to induce a more rapid platelet recovery