Gain In Capacity Research Articles

The effects of early mobilisation and immobilisation on the healing process following muscle injuries.

The biological processes following muscle injury include 2 competitive events; regeneration of muscle fibres and the simultaneous production of granulation tissue. We have studied the effects of early mobilisation and immobilisation on the healing of rat gastrocnemius muscle following partial rupture by a controlled contusion mechanism. Muscle fibre regeneration is inhibited by the formation of dense connective tissue scar. Immobilisation following injury limits the size of the connective tissue area formed within the site of injury; the penetration of muscle fibres through the connective tissue is prominent but their orientation is complex and not parallel with the uninjured muscle fibres. Immobilisation for longer than 1 week is followed by marked atrophy of the injured gastrocnemius muscle. Mobilisation started immediately after injury is followed by a dense scar formation in the injury area prohibiting muscle regeneration. When mobilisation is started after a short period of immobilisation a better penetration of muscle fibre through the connective tissue is found and the orientation of regenerated muscle fibres is aligned with the uninjured muscle fibres. Although a little delay in healing processes in muscles mobilised after short immobilisation was found morphologically, the gain in strength and energy absorption capacity was quite similar and as good as that of muscles treated by early mobilisation alone.

Traffic capacity of cellular mobile communications systems

In a cellular mobile communication system, the traffic capacity of the system is an important quantity, and depends on the way that channels are allocated to calls. Many channel allocation algorithms have been proposed, and this paper makes a direct comparison of some of them. Specifically, the operating regimes considered are fixed channel assignment, dynamic channel assignment, directed retry, and directed handoff. The main conclusion is that directed handoff gives a strong gain in traffic capacity and traffic adaptability for these systems. The paper also discusses some of the factors affecting the future development of mobile communication systems.

Theoretical propositions of life-span developmental psychology: On the dynamics between growth and decline.

Life-span developmental psychology involves the study of constancy and change in behavior throughout the life course. One aspect of life-span research has been the advancement of a more general, metatheoretical view on the nature of development. The family of theoretical perspectives associated with this metatheoretical view of life-span developmental psychology includes the recognition of multidirectionality in ontogenetic change, consideration of both age-connected and disconnected developmental factors, a focus on the dynamic and continuous interplay between growth (gain) and decline (loss), emphasis on historical embeddedness and other structural contextual factors, and the study of the range of plasticity in development. Application of the family of perspectives associated with life-span developmental psychology is illustrated for the domain of intellectual development. Two recently emerging perspectives of the family of beliefs are given particular attention. The first proposition is methodological and suggests that plasticity can best be studied with a research strategy called testing-the-limits. The second proposition is theoretical and proffers that any developmental change includes the joint occurrence of gain (growth) and loss (decline) in adaptive capacity. To assess the pattern of positive (gains) and negative (losses) consequences resulting from development, it is necessary to know the criterion demands posed by the individual and the environment during the lifelong process of adaptation. The study of life-span development is not a homogeneous field. It comes in two major interrelated modes. The first mode is the extension of developmental studies across the life course without a major effort at the construction of metatheory that emanates from life-span work. The second mode includes the endeavor to explore whether life-span research has specific implications for the general nature of developmental theory. The second approach represents the topic of this article. Specifically, the purpose of this article is twofold. First, after a brief introduction to the field of life-span developmental psychology, some prototypical features of the life-span approach in developmental psychology are presented. Second, these features are illustrated by work in one domain: intellectual development. Although the focus of this paper is on life-span developmental psychology and its theoretical thrust, it is important to recognize at the outset that similar perspectives on developmental theory have been advanced in other quarters of developmental scholarship as well (Hetherington & Baltes, in press; Scan; 1986). There is, however, a major difference in the gestalt in which the features of the theoretical perspective of life-span psychology are organized.

Role of Load Tests in Friction Pile Design

In situ measurements of stresses and pore pressures on a model pile shaft, the Piezo‐Lateral Stress (PLS) cell, are combined with theoretical analyses to reconstruct the conditions of a large‐scale pile load test at a site in Empire, LA. Results show that the mode of penetration of open‐ended piles has an important effect on the performance of pile shafts. Pile plugging during driving retards the rates of soil consolidation and the gain in shaft capacity after installation. The Empire experience is used to identify important factors affecting shaft‐soil interaction which require control and/or evaluation during pile load tests. Methods of enhancing the value of pile load test data in the future are recommended.

Analytical and simulation study of simple rearrangeable multiexchange networks

Congestion probabilities for calls in simple three-exchange networks operated with and without rearrangements are determined analytically and by digital simulation. Load-loss curves are obtained, from which the gain in traffic capacity due to rearrangement and degradation due to overload can be found. It is concluded that routing control with rearrangements possesses a potential traffic-handling advantage over conventional automatic alternative routing.

Large state sequential machine realization with minimum ROM capacity

Sequential machines of all types can be implemented using ROMs for the combinational circuit portion of the realization. When large state sequential machines are to be implemented, the capacity of ROMs needed will also be large. A given machine can be implemented by decomposing it in either serial or parallel form (Hartmanis 1960). It is shown in this paper that when a machine M is decomposed under certain prescribed conditions, there is always a saving (gain) in the ROM capacity, compared with the memory capacity needed when the machine is realized without decomposition. A set of formulae for gains associated with serial and parallel decompositions of a p-state machine M is presented. This is followed by an approximate cost analysis.

Delineation of the development of T lymphocytes from leukemic null lymphocytes upon induction by conditioned medium

Null lymphocytes, lacking B- and T-lymphocyte markers, were isolated from PBL of patients with acute lymphocytic leukemia. Upon culture in the presence of medium produced from PHA-stimulated allogeneic lymphocytes, induction of these cells to T lymphocytes occurred. Within 18 hr, they acquired the capacity to form SRBC rosettes and bind complement components, IgG or IgM. This differentiation, as supported by cell cycle kinetic analysis, was accompanied by lymphocyte activation, inferable from warm SRBC rosetting. Capping of these rosettes was identified as indicative of early T lymphocytes. During T-lymphocyte development subclasses bearing complement receptors, followed by IgG and finally IgM receptors appeared. The emergence of subclasses, functionally expressed by a gain in MLC responsiveness and stimulatory capacity reflected T-lymphocyte maturation. Simultaneous with the later decrease of the subclasses was a decrease in MLC reactivity. This elucidation of T-lymphocyte development may help in dissection of the lymphoid system.

Experiences with high tetraplegics.

Of the 1468 patients with traumatic spinal cord injury who were admitted to the Texas Institute for Rehabilitation and Research (TIRR) between 1959 and 1977, 67 patients were complete tetraplegics with motor levels of C4 and above. The age, sex, motor level, aetiology of injury, and initial and final vital capacity of these patients are analysed. A substantial gain in vital capacity was attained in all C4 motor tetraplegics regardless of their initial vital capacity. Twenty patients with motor levels of C3 and above have been admitted to TIRR since 1963. Five of these 20 C3 and above tetraplegics have had bilateral phrenic stimulators implanted. The mortality rates and causes of death in these groups of patients are presented. Survival curves are presented on 615 traumatic spinal cord injuried patients as compared to a standard matched group. Survival curves are also presented for the two groups of high tetraplegics who were admitted to TIRR from 1963 through 1969 and from 1970 through 1977.

Título en español.

Pastos de yerba Estrella en la región húmeda montañosa de Puerto Rico respondieron favorablemente en términos de ganancia de peso y capacidad de pastoreo según se aumentaron los niveles de abonamiento de 1,792 a 3,136 a 4,480 Kg./Ha. (1,600, 2,800 y 4,000 libras/acre) de abono 15-5-10 al año. Con la aplicación de 3,136 Kg./Ha (2,800 libras por acre) al año los pastos de yerba Estrella produjeron 1,337 Kg./Ha. (1,194 libras por acre) de aumento de peso al año y alcanzaron una capacidad de pastoreo equivalente a 6.8 novillos de 273 Kg./Ha. (2.72 novillos de 600 libras por acre). El aumento de peso medio por día y cabeza fue de .61 kg. (1.35 libras). Este no fue afectado por el abonamiento. La digestibilidad aparente del forraje, ya fuera determinada in vitro o calculada a base de los nutrimentos digeribles utilizados por el ganado y el forraje que éste consumió, tampoco fue afectada por el abonamiento. El contenido de proteína del forraje ingerido por el ganado fue muy alto en todos los niveles de abonamiento, variando de 17.4 a 29.1 por 100 a través del año. El contenido en calcio, fósforo y lignina del forraje no fue afectado por el abonamiento ni por la época del año.

Phase Transition of Gonococci in Mammalian Cell Cultures

Neisseria gonorrhoeae was cultivated in mammalian cell cultures in an effort to determine if this environment will elicit a T4 --> T1 transition. Of four avirulent (T4) isolates tested, only one, H4, yielded T1 colonies. This change was consistently obtained in HeLa, WI-38, and MK2 cells, even when the multiplicity of the gonococcal infection was less than 1 per culture. Growth of the gonococci took place primarily on the surface of the cells, as demonstrated by light and electron microscopy, but occasional bacteria were undoubtedly intracellular. T1 colonies were seen at 24 h and were the major population at 48 h. This shift was favored by the presence of viable cells, since smaller yields of T1 were obtained when the cells were irradiated or heat inactivated. It was also favored by low pH, since T1 recovery was reduced when the buffering capacity of the medium was increased. Although the results suggest that T1 gonococci derived from H4 have a selective advantage over T4 in cell cultures, this is not true of all T1 and T4 colony types. F62 T4, which does not undergo a T4 --> T1 shift, propagated as well as T1 in HeLa cell cultures. The change in colony type of strain H4 to T1 was accompanied by formation of pili and by gain in capacity for deoxyribonucleic acid-mediated transformation. It is concluded that gonococci can undergo T4 --> T1 phase transition in mammalian cell cultures, but this property is not retained by all strains.

Accumulation of pyruvate in phenylhydrazine-treated avian red blood cells.

Loss in oxygen capacity which occurs when avian erythrocytes are treated in vitro with phenylhydrazine is completely or partially restored (depending on the initial concentration of phenylhydrazine) on incubation of the cells for 1 hour in the presence of glucose or lactate under anaerobic conditions. Restoration in oxygen capacity is always accompanied by a proportional accumulation of pyruvate (the proportion differs for each substrate) which bears the same relationship to the gain in oxygen capacity as that found for the metabolic reduction of methemoglobin by the avian erythrocyte. However under aerobic conditions pyruvate continued to accumulate after all measurable oxygen capacity restoration (methemoglobin reduction) ceased. This is taken as evidence that in the presence of oxygen either methemoglobin formation continues in the treated cell, after all phenylhydrazine is destroyed or washed out, or that some other ferric iron compound is reduced which will not augment oxygen capacity. At the higher concentrations of phenylhydrazine used not all the oxygen capacity initially lost is restored on incubation even under anaerobic conditions. This inactive molecule is thought to be verdoglobin.