A family of perfect hashing methods

Minimal perfect hash functions are used for memory efficient storage and fast retrieval of items from static sets. We present an infinite family of efficient and practical algorithms for generating order preserving minimal perfect hash functions. We show that almost all members of the family construct space and time optimal order preserving minimal perfect hash functions, and we identify the one with minimum constants. Members of the family generate a hash function in two steps. First a special kind of function into an r-graph is computed probabilistically. Then this function is refined deterministically to a minimal perfect hash function. We give strong theoretical evidence that the first step uses linear random time. The second step runs in linear deterministic time. The family not only has theoretical importance, but also offers the fastest known method for generating perfect hash functions.

On the spectrum for K_{m+2}/K_m designs

The spectrum problem for the decomposition of K-n into copies of the graph K_{m+2}\K_m is solved for n = 0 or 1 (mod 2m + 1). (C) 1997 John Wiley & Sons, Inc.

MHCPEP, a database of MHC-binding peptides: Update 1996

MHCPEP is a curated database comprising over 9000 peptide sequences known to bind MHC molecules. Entries are compiled from published reports as well as from direct submissions of experimental data. Each entry contains the peptide sequence, its MHC specificity and, when available, experimental method, observed activity, binding affinity, source protein, anchor positions and publication references. The present format of the database allows text string matching searches but can easily be converted for use in conjunction with sequence analysis packages. The database can be accessed via Internet using WWW, FTP or Gopher.

The intersection problem for K_4-e designs

A G-design of order n is a pair (P,B) where P is the vertex set of the complete graph K-n and B is an edge-disjoint decomposition of K-n into copies of the simple graph G. Following design terminology, we call these copies ''blocks''. Here K-4 - e denotes the complete graph K-4 with one edge removed. It is well-known that a K-4 - e design of order n exists if and only if n = 0 or 1 (mod 5), n greater than or equal to 6. The intersection problem here asks for which k is it possible to find two K-4 - e designs (P,B-1) and (P,B-2) of order n, with \B-1 boolean AND B-2\ = k, that is, with precisely k common blocks. Here we completely solve this intersection problem for K-4 - e designs.

d-cube decompositions of K-n/K-m

Necessary conditions on n, m and d are given for the existence of an edge-disjoint decomposition of K-n\K-m into copies of the graph of a d-dimensional cube. Sufficiency is shown when d = 3 and, in some cases, when d = 2(t). We settle the problem of embedding 3-cube decompositions of K-m into 3-cube decompositions of K-n; where n greater than or equal to m.

CD4+T cells from HIV-1-infected patients recognize wild-type and mutant human immunodeficiency virus-1 protease epitopes

P>Human immunodeficiency virus (HIV)-1 protease is a known target of CD8+ T cell responses, but it is the only HIV-1 protein in which no fully characterized HIV-1 protease CD4 epitopes have been identified to date. We investigated the recognition of HIV-1 protease by CD4+ T cells from 75 HIV-1-infected, protease inhibitor (PI)-treated patients, using the 5,6-carboxyfluorescein diacetate succinimidyl ester-based proliferation assay. In order to identify putative promiscuous CD4+ T cell epitopes, we used the TEPITOPE algorithm to scan the sequence of the HXB2 HIV-1 protease. Protease regions 4-23, 45-64 and 73-95 were identified; 32 sequence variants of the mentioned regions, encoding frequent PI-induced mutations and polymorphisms, were also tested. On average, each peptide bound to five of 15 tested common human leucocyte antigen D-related (HLA-DR) molecules. More than 80% of the patients displayed CD4+ as well as CD8+ T cell recognition of at least one of the protease peptides. All 35 peptides were recognized. The response was not associated with particular HLA-DR or -DQ alleles. Our results thus indicate that protease is a frequent target of CD4+ along with CD8+ proliferative T cell responses by the majority of HIV-1-infected patients under PI therapy. The frequent finding of matching CD4+ and CD8+ T cell responses to the same peptides may indicate that CD4+ T cells provide cognate T cell help for the maintenance of long-living protease-specific functional CD8+ T cells.

Breast cancer five-year survival in New South Wales women, 1972 to 1991

This study of breast cancer survival is based on analysis of five-year relative survival of 38 362 cases of invasive breast cancer in New South Wales (NSW) women, incident between 1972 and 1991, with follow-up to 1992, using data from the population-based NSW Central Cancer Registry. Survival was ascertained by matching the registry file of breast cancers against NSW death certificates from 1972 to 1992, mainly by automated probabilistic linkage. Absolute survival of cases was compared with expected survival of age- and period-matched NSW women. Proportional hazard regression analysis was used for examination of the effects on excess mortality of age, period of diagnosis and degree of spread at diagnosis. Relative survival at five years increased from 70 per cent in 1972-1976 to 77 per cent in 1987-1991. Survival improved during the 1970s and in the late 1980s. Regression analysis suggested that part of the improved survival in the late 1980s was due to lesser degree of spread at diagnosis, whereas the improved survival during the 1970s may have been due to treatment. Survival was better for those aged 40-49 years (RR = 0.86) and worse for those aged greater than or equal to 70 years (RR = 1.22) compared with the referent group (60-69 years). Excess mortality was much less for those with invasive localised disease than those with regional spread (RR = 3.1) or metastatic cancer (RR = 15.5) at diagnosis. For the most recent period (1987-1991), relative five-year survival was 90, 70 and 18 per cent, respectively, for the three degree-of-spread categories.

The effect of internal thoracic artery grafts on long-term clinical outcomes after coronary bypass surgery

Objectives: We sought to compare long-term outcomes after coronary bypass surgery with and without an internal thoracic artery graft. Methods: We analyzed clinical outcomes over a median follow-up of 6.7 years among 3,087 patients who received coronary bypass surgery as participants in one of 8 clinical trials comparing surgical intervention with angioplasty. We used 2 statistical methods (covariate adjustment and propensity score matching) to adjust for the nonrandomized selection of internal thoracic artery grafts. Results: Internal thoracic artery grafting was associated with lower mortality, with hazard ratios of 0.77 (confidence interval, 0.62-0.97; P = .02) for covariate adjustment and 0.77 (confidence interval, 0.57-1.05; P = .10) for propensity score matching. The composite end point of death or myocardial infarction was reduced to a similar extent, with hazard ratios of 0.83 (confidence interval, 0.69-1.00; P = .05) for covariate adjustment to 0.78 (confidence interval, 0.61-1.00; P = .05) for propensity score matching. There was a trend toward less angina at 1 year, with odds ratios of 0.81 (confidence interval, 0.61-1.09; P = .16) in the covariate-adjusted model and 0.81 (confidence interval, 0.55-1.19; P = .28) in the propensity score-adjusted model. Conclusions: Use of an internal thoracic artery graft during coronary bypass surgery seems to improve long-term clinical outcomes. (J Thorac Cardiovasc Surg 2011; 142: 829-35)

Infrared seeded parametric four-wave mixing for sensitive detection of molecules

We have developed a sensitive resonant four-wave mixing technique based on two-photon parametric four-wave mixing with the addition of a phase matched ''seeder'' field. Generation of the seeder field via the same four-wave mixing process in a high pressure cell enables automatic phase matching to be achieved in a low pressure sample cell. This arrangement facilitates sensitive detection of complex molecular spectra by simply tuning the pump laser. We demonstrate the technique with the detection of nitric oxide down to concentrations more than 4 orders of magnitude below the capability of parametric four-wave mixing alone, with an estimated detection threshold of 10(12) molecules/cm(3).

Semantic memory impairment in temporal lobe epilepsy associated with hippociampal sclerosis

Episodic memory impairment is a well-recognized feature of mesial temporal lobe epilepsy. Semantic memory has received much less attention in this patient population. In this study, semantic memory aspects (word-picture matching, word definition, confrontation and responsive naming, and word list generation) in 19 patients with left and right temporal lobe epilepsy secondary to mesial temporal sclerosis (MTS) were compared with those of normal controls. Patients with LMTS showed impaired performance in word definition (compared to controls and RMTS) and in responsive naming (compared to controls). RMTS and LMTS patients performed worse than controls in word-picture matching. Both patients with left and right mesial temporal lobe epilepsy performed worse than controls in word list generation and in confrontation naming tests. Attentional-executive dysfunction may have contributed to these deficits. We conclude that patients with left and right NITS display impaired aspects of semantic knowledge. A better understanding of semantic processing difficulties in these patients will provide better insight into the difficulties with activities of daily living in this patient population. (C) 2007 Elsevier Inc. All rights reserved.

2m-cycle systems of K2m+1/C-m

For all m greater than or equal to 3 the edges of complete graph on 2m + 1 vertices can he partitioned into m 2m-cycles and an m-cycle.

Phase-dependent fluorescence linewidth narrowing in a three-level atom damped by a finite-bandwidth squeezed vacuum

We examine subnatural phase-dependent linewidths in the fluorescence spectrum of a three-level atom damped by a narrow-bandwidth squeezed vacuum in a cavity. Using the dressed-atom model approach of a strongly driven three-level cascade system, we derive the master equation of the system from which we obtain simple analytical expressions for the fluorescence spectrum. We show that the phase effects depend on the bandwidths of the squeezed vacuum and the cavity relative to the Rabi frequency of the driving fields. When the squeezing bandwidth is much larger than the Rabi frequency, the spectrum consists of five lines with only the central and outer sidebands dependent on the phase. For a squeezing bandwidth much smaller than the Rabi frequency the number of lines in the spectrum and their phase properties depend on the frequency at which the squeezing and cavity modes are centered. When the squeezing and cavity modes are centered on the inner Rabi sidebands, the spectrum exhibits five lines that are completely independent of the squeezing phase with only the inner Rabi sidebands dependent on the squeezing correlations. Matching the squeezing and cavity modes to the outer Rabi sidebands leads to the disappearance of the inner Rabi sidebands and a strong phase dependence of the central line and the outer Rabi sidebands. We find that in this case the system behaves as an individual two-level system that reveals exactly the noise distribution in the input squeezed vacuum. [S1050-2947(97)00111-X].

Vascularized Bone Grafts for Upper Limb Reconstruction: Defects at the Distal Radius, Wrist, and Hand

Vascularized bone grafts have been successfully applied for the reconstruction of bone defects at the forearm, distal radius, carpus, and hand. Vascularized bone grafts are most commonly used in revision cases in which other approaches have failed. Vascularized bone grafts can be obtained from a variety of donor sites, including the fibula, the iliac crest, the distal radius (corticocancellous segments and vascularized periosteum), the metacarpals and metatarsals, and the medial femoral condyle (corticoperiosteal flaps). Their vascularity is preserved as either pedicled autografts or free flaps to carry the optimum biological potential to enhance union. The grafts can also be transferred as composite tissue flaps to reconstruct compound tissue defects. Selection of the most appropriate donor flap site is multifactorial. Considerations include size matching between donor and defect, the structural characteristics of the graft, the mechanical demands of the defect, proximity to the donor area, the need for an anastomosis, the duration of the procedure, and the donor site morbidity. This article focuses on defects of the distal radius, the wrist, and the hand. (J Hand Surg 2010;35A:1710-1718. (C) 2010 Published by Elsevier Inc. on behalf of the American Society for Surgery of the Hand.)

Air Pollution and Mortality in Latin America The Role of Education

Background: People with less education in Europe, Asia, and the United States are at higher risk of mortality associated with daily and longer-term air pollution exposure. We examined whether educational level modified associations between mortality and ambient particulate pollution (PM(10)) in Latin America, using several timescales. Methods: The study population included people who died during 1998-2002 in Mexico City, Mexico; Santiago, Chile; and Sao Paulo, Brazil. We fit city-specific robust Poisson regressions to daily deaths for nonexternal-cause mortality, and then stratified by age, sex, and educational attainment among adults older than age 21 years (none, some primary, some secondary, and high school degree or more). Predictor variables included a natural spline for temporal trend, linear PM(10) and apparent temperature at matching lags, and day-of-week indicators. We evaluated PM(10) for lags 0 and I day, and fit an unconstrained distributed lag model for cumulative 6-day effects. Results: The effects of a 10-mu g/m(3) increment in lag 1 PM(10) on all nonextemal-cause adult mortality were for Mexico City 0.39% (95% confidence interval = 0.131/-0.65%); Sao Paulo 1.04% (0.71%-1.38%); and for Santiago 0.61% (0.40%-0.83%. We found cumulative 6-day effects for adult mortality in Santiago (0.86% [0.48%-1.23%]) and Sao Paulo (1.38% [0.85%-1.91%]), but no consistent gradients by educational status. Conclusions: PM(10) had important short- and intermediate-term effects on mortality in these Latin American cities, but associations did not differ consistently by educational level.