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1.
Stud Appl Math ; 133(1): 18-51, 2014 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-25214676

RESUMEN

The patterning of many developing tissues is orchestrated by gradients of morphogens through a variety of elaborate regulatory interactions. Such interactions are thought to make gradients robust, that is, resistant to changes induced by genetic or environmental perturbations; but just how this might be done is a major unanswered question. Recently extensive numerical simulations suggest that robustness of signaling gradients cannot be attained by negative feedback (of the Hill's function type) on signaling receptors but can be achieved through binding with nonsignaling receptors (or nonreceptors for short) such as heparan sulfate proteoglycans with the resulting complexes degrading after endocytosis. These were followed by a number of analytical and numerical studies in support of the aforementioned observations. However, evidence of feedback regulating signaling gradients has been reported in literature. The present paper undertakes a different approach to the role of feedback in robust signaling gradients. The overall goal of the project is to investigate the effectiveness of feedback mechanisms on ligand synthesis, receptor synthesis, nonreceptor synthesis, and other regulatory processes in the morphogen gradient system. As a first step, we embark herein a proof-of-concept examination of a new spatially uniform feedback process that is distinctly different from the conventional spatially nonuniform Hill function approach.

4.
Arch Clin Neuropsychol ; 14(6): 537-43, 1999 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-14590581

RESUMEN

Impaired depth perception (astereopsis) has been observed in a variety of cerebral pathologies affecting the posterior parietal lobe. In the current study of 93 consecutive head trauma admissions, 24% had complete astereopsis and 41% performed more than 2 SDs below the orthopedic control group mean. Degree of impairment was related to Glascow Coma Scale score, length of posttraumatic amnesia, reduced visuospatial and memory abilities, and the presence of intracranial pathology of the parietal lobes. Impairment was also related to trauma severity in patients without any visualized intracranial pathology, presumably due to diffuse axonal shearing. Clinically meaningful impairment was observed in 25% of this group; 10% had complete astereopsis. Stereoacuity screening requires 1 to 2 minutes. Undetected astereopsis may increase risk for subsequent motor vehicle accidents or falls.

7.
Immigr Minor ; 18(1): 1-28, 1999.
Artículo en Inglés | MEDLINE | ID: mdl-20169682

RESUMEN

The Belgians during the First World War represented the largest refugee movement in British history. Despite the size of this influx - at its peak some 250,000 were present in Britain - there has been an almost total absence of reference to them. This article suggests that this neglect is unfortunate both with regard to our understanding of the First World War and the history of refugees during the twentieth century. In particular, this article stresses the importance of local responses and reactions to the refugees and the significance of place in the process of rebuilding lives and identities in Britain.


Asunto(s)
Aculturación , Características Culturales , Empleo , Historiografía , Dinámica Poblacional , Refugiados , Bélgica/etnología , Empleo/economía , Empleo/historia , Empleo/legislación & jurisprudencia , Empleo/psicología , Etnicidad/educación , Etnicidad/etnología , Etnicidad/historia , Etnicidad/legislación & jurisprudencia , Etnicidad/psicología , Historia del Siglo XX , Humanos , Grupos Minoritarios/educación , Grupos Minoritarios/historia , Grupos Minoritarios/legislación & jurisprudencia , Grupos Minoritarios/psicología , Salud de las Minorías/economía , Salud de las Minorías/etnología , Salud de las Minorías/historia , Salud de las Minorías/legislación & jurisprudencia , Refugiados/educación , Refugiados/historia , Refugiados/legislación & jurisprudencia , Refugiados/psicología , Factores Socioeconómicos , Reino Unido/etnología , Primera Guerra Mundial
9.
Int J Neurosci ; 93(1-2): 141-50, 1998 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-9604176

RESUMEN

The Category Test (CT) and the Wisconsin Card Sort Test (WCST) have long been the major instruments used for the assessment of "frontal lobe" brain damage. These tests have often been used interchangeably by clinicians. However, research to date has disagreed on the extent to which these tests can be interpreted in a similar manner. The current paper examined the interrelationships between the tests in 112 mixed brain injured clients. The results showed relatively small correlations between the tests in the range of .4 to .6 which were eliminated when age, education, premorbid IQ (Vocabulary) and spatial skills (Block Design) were used as covariates. Regression analyses showed clear differences in which WAIS-R tests predicted each test, while factor analysis revealed little overlap between the tests except for a small relationship between the number of WCST categories completed and CT errors. The CT appeared to reflect spatial and spatial analysis skills while the WCST reflected verbal analysis and sequential skills. The results clearly indicate that the tests are not interchangeable and do not reflect the same underlying cognitive skills nor can they be interpreted in the same manner for neuropsychological purposes.


Asunto(s)
Daño Encefálico Crónico/diagnóstico , Daño Encefálico Crónico/fisiopatología , Lóbulo Frontal/fisiopatología , Pruebas Neuropsicológicas , Adolescente , Adulto , Anciano , Daño Encefálico Crónico/psicología , Análisis Factorial , Femenino , Humanos , Inteligencia , Masculino , Persona de Mediana Edad , Análisis de Regresión
15.
Theor Med ; 12(4): 281-93, 1991 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-1801299

RESUMEN

The failure of medical codes to provide adequate guidance for physicians' moral dilemmas points to the fact that some rules of analysis, informed by moral theory, are needed to assist in resolving perplexing ethical problems occurring with increasing frequency as medical technology advances. Initially, deontological and teleological theories appear more helpful, but criticisms can be lodged against both, and neither proves to be sufficient in itself. This paper suggests that to elude the limitations of previous approaches, a method of moral decision making must be developed incorporating both coherence methodology and some independently supported theoretical foundations. Wide Reflective Equilibrium is offered, and its process described along with a theory of the person which is used to animate the process. Steps are outlined to be used in the process, leading to the application of the method to an actual case.


Asunto(s)
Discusiones Bioéticas , Toma de Decisiones , Análisis Ético , Teoría Ética , Ética Clínica , Ética Médica , Personeidad , Códigos de Ética , Humanos , Recién Nacido , Masculino , Principios Morales , Valor de la Vida , Privación de Tratamiento
16.
Diabet Med ; 7(4): 355-9, 1990 May.
Artículo en Inglés | MEDLINE | ID: mdl-2140090

RESUMEN

Therapeutic footwear with cushioned insoles was supplied to 50 diabetic patients with severe peripheral neuropathy and/or peripheral vascular disease (age 59(SD 12) years, known duration of diabetes 17(7) years), 36 of whom had a history of foot ulceration. A follow-up examination was carried out 25(14) months later, except in 8 patients who died from conditions unrelated to their foot lesions, and 1 patient who died from sepsis due to upper limb amputation. Among the surviving 41 patients, intercurrent foot lesions during follow-up occurred in significantly fewer (42%) of the 26 who had worn the shoes regularly than of the 15 who had worn the shoes irregularly (87%, p less than 0.01). At follow-up, only 15% of the 41 patients were being treated for foot-lesions, compared with 78% of these 41 patients before cushioned shoes were provided. It is concluded that the availability of therapeutic shoes with cushioned insoles for diabetic patients at risk of foot lesions decreases the morbidity due to the diabetic foot syndrome.


Asunto(s)
Angiopatías Diabéticas/terapia , Neuropatías Diabéticas/terapia , Enfermedades del Pie/terapia , Zapatos , Diabetes Mellitus Tipo 1/fisiopatología , Diabetes Mellitus Tipo 2/fisiopatología , Femenino , Humanos , Úlcera de la Pierna/terapia , Masculino , Persona de Mediana Edad , Diseño de Prótesis
17.
20.
Placenta ; 8(1): 53-64, 1987.
Artículo en Inglés | MEDLINE | ID: mdl-2954041

RESUMEN

A specific, membrane-bound, Ca2+-activated and Mg2+-dependent adenosine triphosphatase (ATPase) activity is present in the human term placenta. The enzyme activity is fractionated electrophoretically into two distinct forms which correspond to molecular weights of 120,000 and 145,000. Cytohistochemistry localized the Ca2+-ATPase to the chorionic villi of the placental labyrinth, and specific staining was primarily associated with the syncytio- and cytotrophoblast layers as well as the perivascular cells. The enzyme activity is inhibited by phenothiazin and erythrosin B which also significantly inhibit active calcium in vitro by placental microsomal membrane vesicles.


Asunto(s)
ATPasas Transportadoras de Calcio/metabolismo , Calcio/metabolismo , Placenta/enzimología , ATPasa de Ca(2+) y Mg(2+)/metabolismo , ATPasas Transportadoras de Calcio/análisis , ATPasas Transportadoras de Calcio/fisiología , Femenino , Histocitoquímica , Humanos , Embarazo
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