Showing papers by "University of Southern California published in 1973"

Functional ambulation in patients with myelomeningocele.

Abstract: The factors important in achieving good walking status in myelomeningocele include level of paraplegia, the additional anomalies of brain and kidney, the intelligence, and the home environment. In a group of fifty-six patients none of those with lesions of the thoracic level walked and all of those with lesions of the sacral level walked. In those with lesions at lumbar levels (twenty-one lower and nineteen upper) fourteen were community ambulators and five household ambulators. The other twenty-one were either wheel-chair (nineteen) or non-functional ambulators (two) and the level of paraplegia did not seem to matter nor did the extent of surgery. Some very young non-functional ambulators rose in functional level, but in most instances the trend was to deteriorate.

Universal noiseless coding

Abstract: Universal coding is any asymptotically optimum method of block-to-block memoryless source coding for sources with unknown parameters. This paper considers noiseless coding for such sources, primarily in terms of variable-length coding, with performance measured as a function of the coding redundancy relative to the per-letter conditional source entropy given the unknown parameter. It is found that universal (i.e., zero redundancy) coding in a weighted sense is possible if and only if the per-letter average mutual information between the parameter space and the message space is zero. Universal coding is possible in a maximin sense if and only if the channel capacity between the two spaces is zero. Universal coding is possible in a minimax sense if and only if a probability mass function exists, independent of the unknown parameter, for which the relative entropy of the known conditional-probability mass-function is zero. Several examples are given to illustrate the ideas. Particular attention is given to sources that are stationary and ergodic for any fixed parameter although the whole ensemble is not. For such sources, weighted universal codes always exist if the alphabet is finite, or more generally if the entropy is finite. Minimax universal codes result if an additional entropy stability constraint is applied. A discussion of fixed-rate universal coding is also given briefly with performance measured by a probability of error.

Telecommunication systems engineering

Abstract: From the Publisher: This classic graduate- and research-level texty by two leading experts in the field of telecommunications is essential reading for anyone workign today in space and satellite digital communicatiions and those seeking a wider background in statistical communication theory and its applications. Ideal for practicing engineers as well as graduate students in communication systems courses, the book clearly presents and develops theory that can be used in the design and planning of telecommunication systems operating with either small or large performance margins. The book includes in its coverage a theory for use in the design of one-way and two-way phase-coherent and communication systems; and analysis and comparison of carrier and suppressed carrier synchronization techniques; treatment of the band-pass limiter theory; unification of phase-coherent detection with perfect and noisy synchronization reference signals. Convolutional codes, symbol synchronization, and noncoherent detection of M-ary signals are among the otehr subjects addressed in this comprehensive study. Dr. Lindsey, who is with the Communication Sciences Institute at the University of Southern California, and Dr. Simon, who is with the Jet Propulsion Laboratory at the California Institute of Technology, include at the end of each chapter a comprehensive set of problems that demonstrate the application of the theory developed. Unabridged Dover (1991) republication of the edition published by Prentice-Hall, Inc., Englewood Cliffs, N.J., 1973.265 line illustrations. 3 photographs. References at chapter ends. Problems. Index. xviii + 574pp. 5 3/8 x 8 1/2. Paperbound.

Level-crossing problems for random processes

Abstract: In a variety of practical problems involving random processes, it is necessary to have statistical information on their level-crossing properties. This paper presents a survey of known results on certain aspects of this problem and provides a basis for further study in the area. The goal has been to give a broad view of the problems considered in the literature and a brief indication of the techniques used in their solution. Much material of a more or less historical nature has been included since, to the authors' knowledge, no other survey of this nature exists.

Computer analysis of postanesthetic deaths

Abstract: Of 34,145 consecutive surgical patients who were attended by an anesthesiologist, 645 died within the first seven days. Two prime determinants of mortality emerged: 1) the physical status of the patient, and 2) the judgment and skill of the physicians. Mortality was highest in cardiovascular and bra

Easily Testable Iterative Systems

Abstract: It has been shown that the number of tests required to detect all faults in a one-dimensional unilateral combinational iterative array consisting of p cells will, in general, be proportional to p. In this paper we consider properties of such systems that enable them to be tested with a fixed constant number of tests independent of p, the number of cells in the system. Such systems are referred to as C-testable. Necessary and sufficient conditions on the basic cell state table are derived for an iterative system to be C-testable. It is shown that an arbitrary N-state cell table can be augmented by the addition of, at most, one row and less than [log2 N]2 columns (for N ≥ 2) so as to be C-testable.

Necrotizing sialometaplasia. A disease simulating malignancy.

Abstract: Results of a clinicopathologic study of seven cases of a previously unreported disease of minor salivary gland are presented. Necrotizing sialometaplasia is a disease of adults with four of seven patients being in the sixth decade of life. In every case, this benign inflammatory process involved only the tissues covering the hard palate, and, in six instances, it was characterized by ulceration. Lobular necrosis and marked squamous metaplasia of salivary gland are consistent features. Microscopically, necrotizing sialometaplasia shows marked similarity to mucoepidermoid carcinoma, and criteria are presented to aid in distinguishing these two conditions. There have been no recurrences following local surgical excision. Etiologic factors remain obscure.

Raman cross section of some simple gases

Abstract: The differential Raman cross sections of the main Raman-active vibrations have been measured in the gases N2, O2, H2, CO, NO, CO2, SO2, N2O, H2S, NH3, ND3, CH4, C2H6, and C6H6 using 488.0-nm laser light. The present results are compared with previous measurements made at other wavelengths. The Raman cross sections of the rotational lines in the diatomic gases were also measured, as were the vibrational-rotational lines of O2 and N2. Absolute measurement of the Raman cross sections were performed two ways: (i) by calibrating the Raman spectrometer, and (ii) by comparing the unknown against liquid benzene (for which the Raman cross section has been measured). Results of these measurements compare reasonably well with previous determinations for which corrections for the υ4 frequency dependence were made.

Gel Electrophoresis of Avian Leukosis and Sarcoma Viral RNA in Formamide: Comparison with Other Viral and Cellular RNA Species

Abstract: Class a and class b 30 to 40S RNA subunits obtained by heat dissociation from the 60 to 70S RNA complex of avian tumor viruses were compared with several RNA standards by electrophoresis in formamide-polyacrylamide gels. Class a RNA was found to have a lower electrophoretic mobility and hence probably a higher molecular weight than class b RNA. The absolute molecular weight of class a and b RNA could not be determined with accuracy, because the relationship between logarithm of molecular weight and mobility of the RNA standards was not linear. The size of class a RNA fell into the range of 2.4 × 106 to 3.4 × 106 daltons and that of class b into the range of 2.2 × 106 to 2.9 × 106 daltons, depending on the standards used. The possible biological significance of this difference is discussed.

Garlock Fault: An Intracontinental Transform Structure, Southern California

Abstract: The northeast- to east-striking Garlock fault of southern California is a major strike-slip fault with a left-lateral displacement of at least 48 to 64 km. It is also an important physiographic boundary since it separates along its length the Tehachapi–Sierra Nevada and Basin and Range provinces of pronounced topography to the north from the Mojave Desert block of more subdued topography to the south. Previous authors have considered the 260-km-long fault to be terminated at its western and eastern ends by the northwest-striking San Andreas and Death Valley fault zones, respectively. We interpret the Garlock fault as an intracontinental transform structure which separates a northern crustal block distended by late Cenozoic basin and range faulting from a southern, Mojave block much less affected by dilational tectonics. Earlier ideas that the Garlock fault terminates eastward at the Death Valley fault zone appear to us to be in error, although right-lateral offsetting of the Garlock along that zone by about 8 km is necessary. Displacement along the Garlock fault must increase westward from its eastern terminus, a point of zero offset now buried beneath alluvial deposits in Kingston Wash to the east of the Death Valley fault zone. Much of the displacement on the Garlock fault due to east-west components of basin and range faulting appears to have been derived from block faulting in the area between Death Valley and the Nopah Range. Westward displacement of the crustal block north of the Garlock by extensional tectonics within it totals 48 to 60 km in the Spangler Hills–Slate Range area and probably continues to increase westward at least as far as the eastern frontal fault of the Sierra Nevada. Westward shifting of the northern block of the Garlock has probably contributed to the westward bending or deflection of the San Andreas fault where the two faults meet. Many earlier workers have considered that the left-lateral Garlock fault is conjugate to the right-lateral San Andreas fault in a regional strain pattern of north-south shortening and east-west extension, the latter expressed in part as an eastward displacement of the Mojave block away from the junction of the San Andreas and Garlock faults. In contrast, we regard the origin of the Garlock fault as being directly related to the extensional origin of the Basin and Range province in areas north of the Garlock. Recent models for development of that province related to intracontinental spreading east of an east-dipping subduction zone along the Cenozoic margin of western North America may best account for the differential east-west extension which has occurred in the crustal blocks to the north and south of the Garlock fault. Other possible examples of intracontinental transform faults in the southwestern Cordillera with geometries similar to that of the Garlock fault include the left-lateral Santa Cruz–Sierra Madre fault zone along the southern margin of the western Transverse Ranges, and the right-lateral Las Vegas shear zone and Agua Blanca fault of Baja California.

A Spontaneous Lower Motor Neuron Disease Apparently Caused by Indigenous Type-C RNA Virus in Wild Mice

Abstract: Abstract A high incidence of spontaneous lower-limb paralysis occurred in a population of wild mice (Mus musculus) which had a high incidence of naturally occurring lymphoma and elevated indigenous type-C virus activity. Experimental transmission evidence indicated that both the neurologic and lymphomatous disorders almost certainly were caused by the indigenous type-C virus. The virus appeared to have a direct neurotropic effect on anterior horn neurons in the lower spinal cord.

Differences in Collagen Metabolism between Normal and Osteoarthritic Human Articular Cartilage

Abstract: Normal human articular cartilage synthesizes only one type of a chain, which exhibits the chromatographic behavior of the αl(II) chains described for chick and bovine cartilage. Osteoarthritic cartilage, on the other hand, synthesizes in addition a collagen containing α2 chains and β components. The different structural features of the two types of collagen may account for some of the functional defects of osteoarthritic cartilage.

Harper-dorn creep in al, pb, and sn

Abstract: High-temperature creep has been studied in lead and tin in the stress range of 10−6 to 10−4G over a range of temperatures near the melting point. A composite plot of dimensionless parameter•/γkT/DGb vsτ/G revealed a transition from a high stress region (with slope ∼4.9 for lead and ∼6.6 for tin) to a low stress region (with slope ∼1 for both metals), at stresses of ∼2 × 10-5G for lead and ∼10−5G for tin. The creep behavior in the low stress region is identical to that attributed to creep of the Harper-Dorn type. In addition, earlier work on aluminum in the low stress region is confirmed using polycrystalline as well as single crystal samples.

Intergenerational Relations and Continuities in Socialization

Abstract: The concept of “generations” is important in analyses of socialization, representing a crucial link between individual development and the broader social and historical context. Intergenerational relations are characterized in this chapter in terms of macro- and micro-perspectives on time, social structure, and socialization. The concept “generation” is defined in two ways: generation as cohort and as lineage, corresponding to these two levels of analysis. Relations between generations are seen as a continuous bilateral negotiation in which the young and the old exchange information and influence from their respective positions in developmental and historical time. There are inevitable intergenerational differences, stemming from contrasting types of contact with cultural institutions, differences in orientation toward future time, age differentials in social position, and within-cohort solidarity. There are also inevitable intergenerational similarities, resulting from interdependence, explicit attempts at transmission, and mutual effect-informational dependence. These factors which lead to difference and similarity between generations can be seen as one element in broader socio-cultural change, as generational units are involved in the production, testing, and selection of cultural alternatives in a feedback process .

Impaired Atrial Receptor Responses in Dogs with Heart Failure Due to Tricuspid Insufficiency and Pulmonary Artery Stenosis

Abstract: In a study of the effects of heart failure on the responses of cardiac receptors, ten dogs were subjected to tricuspid avulsion and pulmonary artery stenosis. One case of spontaneous heart failure was included in the series, and the electrical spike responses of atrial receptors to progressive changes in atrial stretch induced by infusion and hemorrhage were contrasted with those in normal control dogs. In the control dogs, the number of spikes per cycle increased very sharply with moderate, i.e., 5-10 cm H2O, venous pressure increments before reaching a maximum at 20 cm H2O. In the experimental dogs, the firing rate failed to increase to the same extent despite large increases in pressure. The resulting sets of curves exhibited a sharp dichotomy. This evidence for the impaired response of elements of the subendocardial receptor network is compatible with a decrease in the sensitivity of feedback mechanisms responsible for the regulation of sodium and water metabolism.

Male Pseudohermaphroditism Due to Testicular 17β-Hydroxysteroid Dehydrogenase Deficiency1

Abstract: A 46-yr-old phenotypic female with XY genotype presented an unusual form of nonfamilial male pseudohermaphroditism with gynecomastia. Seemingly a normal girl until puberty, the patient developed breasts but became virilized as well at age 13 and failed to menstruate. No uterus was found above the short and blindending vagina. Serum testosterone (T) was subnormal for a male while urinary 17-ketosteroids (17KS) were elevated. The disorder was clarified when increased serum LH concentrations and a 10-fold elevation in serum androstenedione (A) were found. Serum A and estrone (E1) concentrations doubled following HCG stimulation while little change in serum T was observed. Exogenous T suppressed scrum LH by 50% and lowered serum A, E1 and estradiol (E2) to normal or subnormal levels. Dexamethasone suppression and ACTH stimulation studies revealed normal adrenal function. Blood production, metabolic clearance, and A to T conversion rates indicated that 91% of circulating T was derived from A which was produced...

Testosterone in the Fetal Rat Testis

Abstract: Testes of fetal rats possess the enzymes necessary for converting radioactive acetate to radioactive testosterone as early as 15.5 days of intrauterine life. The fetal testis is, therefore, capable of formation do novo of testosterone through the period of sexual differentiation of the internal genitalia. Testosterone was measured in testicular tissue of fetal rats. Values ranged from as low as 0.09 ng/mg at 15.5 days of gestation to 2.76 ng/mg at 18.5 days of gestation. The sharp rise at 18.5 days of fetal age coincides with morphological evidence that relatively large amounts of testosterone are necessary for Wolifian duct stabilization at this time. Fetal testes were also incubated with [‘4C] acetate or [‘H] pregnenolone. Whereas conversion of both substrates to radioactive testosterone occurred at 15.5 and 16.5 days of gestation, no such conversion was evident at 14.5 days of fetal age with either substrate. Nonradioactive testosterone was, however, measurable in incubation from all three time periods. Neither radioactive nor nonradioactive testosterone was detectable in incubations of fetal ovaries with radioactive acetate or pregnenolone at 15 to 20 days of gestation. The influence of steroid androgens on

Treatment of displaced subcapital and transcervical fractures of the femoral neck by muscle-pedicle-bone graft and internal fixation. A preliminary report on one hundred and fifty cases.

Abstract: Beginning in 1967, all qualified patients (under seventy years of age, ambulatory with a displaced femoral fracture in the neck or subcapital) were treated either by use a fibular graft (twenty-one not considered in detail in this report) or by an iliac graft with quadriceps muscle pedicle in addition to Hagie pins Four of the 150 patients were lost to follow-up There were seven deaths and three infections which required removal of the femoral head Of the remaining 136 patients, there were fifteen non-unions (11 per cent) When, in addition, a posterior defect was found and was filled with bone graft, union occurred in 97 per cent (sixty-four of sixty-six) Of the fifteen non-unions, eight had unsatisfactory reductions or were in uncooperative patients Late segmental collapse occurred in five patients (of sixty-three followed eighteen or more months) and varus position in sixteen At follow-up, five patients were practically confined to a wheel chair, fifteen used a walker and seventeen a cane, while the rest were freely ambulatory

The absorption cross sections of N2, O2, CO, NO, CO2, N2O, CH4, C2H4, C2H6 and C4H10 from 180 to 700Å

Abstract: The absorption cross sections of N2, O2, CO, NO, CO2, N2O, CH4, C2H4, C2H6, C4H10 have been measured photoelectrically in the 180–700 A region using synchrotron radiation. The absorption cross sections in the region λ ≥ 500 A was found to be structureless and to increase monotonically with wavelength for all gases. The positions of the structure observed in the 520–720 A region for N2, O2, CO2 and N2O are consistent with the various Rydberg series reported by previous authors.

Laboratory observations of shear-layer instability in a stratified fluid

Abstract: Instability and transition to turbulence is studied in a shear layer between two streams of different salinities and velocities. The viscous layer between the two streams is 15–18 times thicker than the diffusion layer. When the initial layer Richardson number is low, the instability organizes the shear-layer vorticity into discrete lumps as in the homogeneous case. Here the similarity ends. The homogeneous shear layer continues to grow by the combination of neighboring vertical lumps (vortex pairing). In the stratified shear layer, the pairing process is stopped completely, and the vorticity is redistributed along the interface. This redistribution generates interfacial waves. The interfacial waves and the residual turbulence eventually decay, and the shear flow approaches a laminar state.