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  • 1
    Electronic Resource
    Electronic Resource
    Locality-preserving hash functions for general purpose parallel computation (1994)
    Springer
    Algorithmica 12 (1994), S. 170-181 
    Details
    ISSN: 1432-0541
    Keywords: General-purpose parallel computation ; Communication latency ; Block PRAM ; Locality ; PRAM simulations ; Universal hashing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract Consider the problem of efficiently simulating the shared-memory parallel random access machine (PRAM) model on massively parallel architectures with physically distributed memory. To prevent network congestion and memory bank contention, it may be advantageous to hash the shared memory address space. The decision on whether or not to use hashing depends on (1) the communication latency in the network and (2) the locality of memory accesses in the algorithm. We relate this decision directly to algorithmic issues by studying the complexity of hashing in the Block PRAM model of Aggarwal, Chandra, and Snir, a shared-memory model of parallel computation which accounts for communication locality. For this model, we exhibit a universal family of hash functions having optimal locality. The complexity of applying these hash functions to the shared address space of the Block PRAM (i.e., by permuting data elements) is asymptotically equivalent to the complexity of performing a square matrix transpose, and this result is best possible for all pairwise independent universal hash families. These complexity bounds provide theoretical evidence that hashing and randomized routing need not destroy communication locality, addressing an open question of Valiant.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01185209
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Experimental laparoscopic aortobifemoral bypass (1995)
    Springer
    Surgical endoscopy and other interventional techniques 9 (1995), S. 894-897 
    Details
    ISSN: 1432-2218
    Keywords: Laparoscopy ; Peripheral vascular disease ; Aortobifemoral bypass ; Retroperitoneal approach ; Abdominal-wall lifting device
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The goal of the present study is to develop a technique for laparoscopic aortobifemoral bypass. Piglets weighing between 60 and 78 kg were anesthetized with halothane. The lateral retroperitoneal approach was preferred to the more familiar anterior transperitoneal approach and was successfully completed in 19 piglets. The piglets were placed in the right lateral decubitus position. The first port (2 cm) was inserted halfway between the tip of the 12th rib and the iliac crest. Four other trocars were placed in the retroperitoneum after balloon inflation had allowed creation of a space which permitted visualization of the aorta from the left renal artery down to the aorto-iliac junction. After evacuation of the retropneumoperitoneum, the cavity was maintained using an abdominal lift device and a retractor. Using this approach, we performed four aortobifemoral bypasses (end-to-end aortic anastomosis) after conventional intravenous heparinization (100 IU/kg) in less than 4 h. Blood loss did not exceed 250 ml and the hematocrit remained stable. Postmortem evaluation of the grafts revealed they were positioned as in a conventional bypass, their limbs having followed in the created retroperitoneal tunnels along the path of the native arteries. No mortality occurred before sacrifice of the animals. We believe that this first performed series of totally retroperitoneal laparoscopic aortobifemoral bypasses in the porcine model is useful in preparation for human application due to the anatomical similarities in the periaortic region.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00768886
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Effect of antihypertensive formulation on health service expenditures (1993)
    Springer
    Clinical autonomic research 3 (1993), S. 363-368 
    Details
    ISSN: 1619-1560
    Keywords: Compliance ; Health care expenditures ; Health policy ; Hypertension ; Medicaid ; Pharmaceutical formulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A Major barrier to the management of hypertension is the extent to which patients comply with the treatment regimen. Herein we report the findings of a retrospective analysis designed to discern the relationship between antihypertensive formulation, regimen compliance and the utilization of health care services. Data for this analysis were derived from the state of South Carolina's Medicaid computer archive. The study population consisted of 1 000 randomly selected beneficiaries initially prescribed one of the following antihypertensive regimens as monotheraphy: atenolol (daily); captopril (twice daily); oral clonidine (twice daily); transdermal clonidine (once a week); diltiazem (twice daily); enalapril (twice daily); metoprolol (twice daily); prazosin (twice daily); terazosin (daily); and verapamil-SR (daily). Multivariate regression analysis was used to determine the incremental influence of selected demographic characteristics, utilization of medical services prior to diagnosis for hypertension, initial antihypertensive medication, medication possession ratio for antihypertensive therapy, and the number of maintenance medications for disease state processes other than hypertension on post-period health care expenditure. Results indicate that patients initially prescribed antihypertensive medication requiring daily or weekly administration experience infrequent changes in their therapeutic regimen, far less use of concomitant therapy for blood pressure control, an increased utilization of antihypertensive medication, and a decrease in the use and cost of physician, hospital and laboratory services.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01829454
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
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