Executing algorithms with hypercube topology on torusmulticomputers

Many parallel algorithms use hypercubes as the communication topology among their processes. When such algorithms are executed on hypercube multicomputers the communication cost is kept minimum since processes can be allocated to processors in such a way that only communication between neighbor processors is required. However, the scalability of hypercube multicomputers is constrained by the fact that the interconnection cost-per-node increases with the total number of nodes. From scalability point of view, meshes and toruses are more interesting classes of interconnection topologies. This paper focuses on the execution of algorithms with hypercube communication topology on multicomputers with mesh or torus interconnection topologies. The proposed approach is based on looking at different embeddings of hypercube graphs onto mesh or torus graphs. The paper concentrates on toruses since an already known embedding, which is called standard embedding, is optimal for meshes. In this paper, an embedding of hypercubes onto toruses of any given dimension is proposed. This novel embedding is called xor embedding. The paper presents a set of performance figures for both the standard and the xor embeddings and shows that the latter outperforms the former for any torus. In addition, it is proven that for a one-dimensional torus (a ring) the xor embedding is optimal in the sense that it minimizes the execution time of a class of parallel algorithms with hypercube topology. This class of algorithms is frequently found in real applications, such as FFT and some class of sorting algorithms     

Large-bandwidth frequency conversion in high-NA step index opticalfibers

Using high-NA step index optical fibers, we show, theoretically, that large-bandwidth second-harmonic generation and sum frequency generation can be achieved at conversion frequencies in the visible region of the spectrum     

Long-term results after allogeneic bone marrow transplantation for chronic myelogenous leukemia in chronic phase: a report from the Chronic Leukemia Working Party of the European Group for Blood and Marrow Transplantation

The purpose of this study was to determine the long-term results of allogeneic bone marrow transplantation for chronic myeloid leukemia. A retrospective analysis was carried out of the outcome of 373 consecutive transplants performed at 38 European institutions between 1980 and 1988 and reported to the registry of the European Group for Blood and Marrow Transplantation. All transplants were carried out for first chronic phase of chronic myelogenous leukemia using unmanipulated marow cells from HLA-identical sibling donors. The probability of survival and leukemia-free survival at 8 years were 54% (95% CI: 49-59) and 47% (95% CI: 41-52) respectively. The probabilities of developing acute GVHD (II-IV) at 100 days and chronic GVHD at 4 years after transplant were 47% (95% CI: 41-53) and 52% (95% CI: 46-58) respectively. The probabilities of transplant-related mortality and leukemic relapse 8 years after BMT were 41% (95% CI: 36-48) and 19% (95% CI: 14-25), respectively. Transplant within 12 months of diagnosis was associated with reduced transplant-related mortality (34 vs 45%, P = 0.013) and resulted in improved leukemia-free survival (52 vs 44%, P = 0.03). The probability of relapse was significantly reduced in patients who developed chronic GVHD (RR = 0.33, P = 0.004). The probability of relapse occurring more than 2 years after transplant was increased more than five-fold in patients transplanted from a male donor (RR = 5.5, P = 0.006). Sixty-seven patients in hematologic remission were studied for residual disease by two-step RT/PCR for BCR-ABL mRNA and 61 (91%) tested negative. We conclude that bone marrow transplantation can induce long-term survival in approximately one-half of CML patients; the majority of survivors have no evidence of residual leukemia cells when studied by molecular techniques. The probability of late relapse is increased with use of a male donor.     

Qualitative approach: a contribution to nursing

This paper focus on some characteristics of the qualitative methodology. Some of these methods are explored such as: participatory research, phenomenology, grounded theory and ethnography critical theory Perspectives of their utilization in nursing research are examined.     

Heterogeneity in susceptibility to metronidazole among Helicobacter pylori isolates from patients with gastritis or peptic ulcer disease

Combination therapies that include metronidazole (MTZ) are the most successful therapies used in eradicating Helicobacter pylori. In this study, the prevalence and the relevance of heterogeneity in susceptibility to MTZ among H. pylori populations of 156 patients were evaluated. The results of this study show that 37 patients (24%) were infected with MTZ-resistant H. pylori (MIC > or = 8 micrograms/ml). Furthermore, 33% (52 of 156) of the patients were found to be infected with H. pylori populations heterogeneous for their susceptibility to MTZ. The reassessment of the MICs of MTZ for these 52 H. pylori populations revealed MTZ resistance in 28 of them, increasing the number of MTZ-resistant H. pylori populations among the 156 patients to 65 (42%). Out of 20 isolates, 2 (10%) heterogeneous in their susceptibility to MTZ also appeared to be heterogeneous at the genome level as determined by randomly amplified polymorphic DNA fingerprinting. In conclusion, the results show the limitations and risk of possible misinterpretations when only a single colony, picked from the primary H. pylori populations isolated from patients, is analyzed for its susceptibility to MTZ.     

Heterochromatin effects on the frequency and duration of LCR-mediated gene transcription

Organ transplantation is associated with an early bone loss that subsequently increases the risk of osteopenia and bone fractures. It is not known whether bone loss continues in long-term survivors, but persistent bone demineralization could further jeopardize an already diminished bone mass. To better define long-term bone status of kidney transplant recipients (KTR), we conducted cross-sectional and longitudinal evaluations of bone mineral density (BMD) in 70 KTR with a mean posttransplantation time of 8.1 years. BMD was determined by dual-energy X-ray absorptiometry and was repeated in 55 of the patients after a mean follow-up period of 22 +/- 5 months. Lumbar and femoral osteopenia, defined as a BMD lower than 2 standard deviations from mean value of sex- and age-matched controls, was present in 28.6% and 10.5% of patients, respectively. There was a significant negative correlation between cumulative prednisone dose and adjusted lumbar as well as femoral BMD (R = 0.45, P < 0.001 and R = 0.29, P < 0.05, respectively). Five patients had a vertebral BMD below a fracture threshold of 0.777 g/cm2. Vertebral fractures (VF) were found in four men and were associated with higher prednisone dosage (P < 0.05), larger cumulative prednisone dose (P < 0.05), and significantly lower BMD values. According to World Health Organization recent criteria for women, prevalences of lumbar and femoral osteopenia and lumbar and femoral osteoporosis in female patients reach 75%, 65%, 33%, and 10%, respectively. The longitudinal part of the study showed a persistent pathological lumbar demineralization process. Over the study period, BMD, expressed as a percentage of that of controls, decreased from 89 +/- 14% to 86 +/- 14% (P < 0.001). Annual change of bone mass was -1.7 +/- 2.8% per year. Accelerated vertebral bone loss (defined as a decrease of BMD, expressed as a percentage of that of controls, of more than 1% per year) was present in 56% of patients and was associated with higher prednisone dosage (P < 0.01). In conclusion, although VF are relatively infrequent in long-term survivors of renal transplantation, osteopenia is a frequent finding, and a substantial proportion of women present lumbar osteoporosis. An ongoing demineralization process of the spine is also demonstrated and probably contributes to long-term spinal osteoporosis incidence. Prednisone dosage remains the most constantly isolated risk factor.     

In-laboratory removal of femoral sheath following protamine administration in patients having intracoronary stent implantation

Two hundred twenty-eight patients with successful coronary stent implantation were randomized either to protamine administration and femoral sheath removal (group I, n = 117) or no heparin neutralization and delayed sheath removal (group II, n = 111). The hospital stay after treatment was shorter in patients receiving protamine; therefore, protamine use for neutralizing circulating heparin may be safely administered immediately after stent implantation.     

T cell responsiveness correlates differentially with antibody isotype levels in clinical and asymptomatic filariasis

To establish the relationships among T and B cell responses, active infection, and clinical manifestations in lymphatic filariasis, filarial-specific lymphocyte proliferation, IgG antibody isotypes, and IgE levels were determined in an exposed population: 31 asymptomatic amicrofilaremics, 43 microfilaremics, 12 symptomatic amicrofilaremics, and 52 elephantiasis patients. Lymphocyte proliferation was higher in elephantiasis patients and asymptomatic amicrofilaremics than in microfilaremics (P < .004). A proportion of asymptomatic amicrofilaremics (32%), elephantiasis patients (37%), and symptomatic amicrofilaremics (58%) showed antigen-specific lymphocyte unresponsiveness, and lymphocyte proliferation to filarial antigens correlated negatively with specific IgG4 levels (rho = -0.315, P < .001). As elevated specific IgG4 is an indicator of active infection, it is argued that active infection may result in lymphocyte hyporesponsiveness irrespective of clinical category. Of those with elevated specific IgE levels and high T cell proliferative responses, 70% had elephantiasis, suggesting these factors have a role in pathology. However, the existence of a proportion of elephantiasis patients with low anti-filarial IgE and T cell unresponsiveness to filarial antigens suggests that elephantiasis can be caused by distinct processes.     

ACAT inhibitors derived from hetero-Diels-Alder cycloadducts of thioaldehydes

Acyl-CoA:cholesterol acyltransferase (ACAT) is the enzyme largely responsible for intracellular cholesterol esterification. A systemic inhibitor of ACAT is believed to be able to slow or even reverse the atherosclerotic process. Towards that goal, a series of cyclic sulfides, derived from the hetero-Diels-Alder reaction of thioaldehydes with 1,3-dienes, and bearing carboxamide substituents, were prepared and evaluated for in vitro (in several tissues and species) and ex vivo ACAT inhibition. Minor changes in subsequent structure were found to have a significant effect in optimization of the biological activity of this series of compounds.     

Data collection: evaluation of a pilot model

The overall purpose of this study was to explore nurses' feelings about the applicability and adequacy of a pilot model of nursing assessment (PMNA) developed for coronary care units (CCU) in order to obtain data that could help in establishing a definitive model. The evaluation, performed by 11 CCU nurses, showed that they considered the development and implementation of PMNA as valuable, and that its design was adequate for interviewing cardiac patients. These results will be employed in the elaboration of a definitive model of nursing assessment.