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The state of American management.

Every year, the president of the United States offers his State of the Union address. Here, from one of the most respected managers in America, is a report on the State of American Management. The state of management, says Walter B. Wriston, is good. Despite the predictions of America's decline, our economy continues to prosper. That is because of this fundamental truth: the United States is the only country in the world that renews itself daily. This is the Age of Pluralism, and U.S. business is based on pluralism. The spirit of the entrepreneur has entered the mainstream of U.S. management, transforming bureaucracy and emphasizing leadership. Today's top executives need to be more like politicians than the number-crunchers of yesterday. At the same time, information is flowing more freely, so corporations are eliminating layers of managers who were really just transmission lines. And top managers are learning to listen to the people who are closest to the work. Everyone today is a knowledge worker. The accelerating pace of knowledge has put a greater premium than ever on talent. Globalization is a big part of this new world. From the manager's viewpoint, globalization means that "you're in a marketplace where you're suddenly waking up with a guy...from a country you're not too sure where it is, who's eating your lunch in your hometown." To understand global competition, managers in large and small companies need broad vision. Finally, to deal with change, U.S. managers must confront some issues at home. For instance, our accounting systems are obsolete, both in companies and in our national accounts.(ABSTRACT TRUNCATED AT 250 WORDS)

Administrative Personnel↗
PubMed2006

Neural blackboard architectures of combinatorial structures in cognition.

Human cognition is unique in the way in which it relies on combinatorial (or compositional) structures. Language provides ample evidence for the existence of combinatorial structures, but they can also be found in visual cognition. To understand the neural basis of human cognition, it is therefore essential to understand how combinatorial structures can be instantiated in neural terms. In his recent book on the foundations of language, Jackendoff described four fundamental problems for a neural instantiation of combinatorial structures: the massiveness of the binding problem, the problem of 2, the problem of variables, and the transformation of combinatorial structures from working memory to long-term memory. This paper aims to show that these problems can be solved by means of neural "blackboard" architectures. For this purpose, a neural blackboard architecture for sentence structure is presented. In this architecture, neural structures that encode for words are temporarily bound in a manner that preserves the structure of the sentence. It is shown that the architecture solves the four problems presented by Jackendoff. The ability of the architecture to instantiate sentence structures is illustrated with examples of sentence complexity observed in human language performance. Similarities exist between the architecture for sentence structure and blackboard architectures for combinatorial structures in visual cognition, derived from the structure of the visual cortex. These architectures are briefly discussed, together with an example of a combinatorial structure in which the blackboard architectures for language and vision are combined. In this way, the architecture for language is grounded in perception. Perspectives and potential developments of the architectures are discussed.

Cognition↗
PubMed2000

A comparison of natural-image-based models of simple-cell coding.

Models such as that of Olshausen and Field (O&F, 1997 Vision Research 37 3311-3325) and principal components analysis (PCA) have been used to model simple-cell receptive fields, and to try to elucidate the statistical principles underlying visual coding in area V1. They connect the statistical structure of natural images with the statistical structure of the coding used in V1. The O&F model has created particular interest because the basis functions it produces resemble the receptive fields of simple cells. We evaluate these models in terms of their sparseness and dispersal, both of which have been suggested as desirable for efficient visual coding. However, both attributes have been defined ambiguously in the literature, and we have been obliged to formulate specific definitions in order to allow any comparison between models at all. We find that both attributes are strongly affected by any preprocessing (e.g. spectral pseudo-whitening or a logarithmic transformation) which is often applied to images before they are analysed by PCA or the O&F model. We also find that measures of sparseness are affected by the size of the filters--PCA filters with small receptive fields appear sparser than PCA filters with larger spatial extent. Finally, normalisation of the means and variances of filters influences measures of dispersal. It is necessary to control for all of these factors before making any comparisons between different models. Having taken these factors into account, we find that the code produced by the O&F model is somewhat sparser than the code produced by PCA. However, the difference is rather smaller than might have been expected, and a measure of dispersal is required to distinguish clearly between the two models.

Models, Neurological↗
PubMed1997

[Structure of human resources in a public hospital in Chile: an experience in introducing changes].

This article discusses the structural and operational reform process that took place beginning in 1994 in Luis Calvo Mackenna Hospital, a tertiary pediatric care facility run by Oriente Metropolitan Health Center in Santiago, Chile. The formation of the Chilean health care system is briefly outlined, along with the changes brought about by the military government in 1979 and other transformations introduced by the first democratic government in 1990 and by the second one, in 1994. In spite of Chile's favorable health indicators and of the current government's desire to establish equitable services and to launch a decentralized system, the health care system that was fundamentally modeled in the fifties and sixties has failed to respond successfully to the demographic transition and to the population's new epidemiologic profile. One of the main problems is that services at the secondary and tertiary levels lack what is necessary to respond to the demand. Under a new leadership with an interest in modern administrative methods, clinical services at Luis Calvo Mackenna Hospital were restructured with new departments and units, a study of the organizational climate was carried out, the entire staff was intensively trained so as to generate a spirit of involvement and a new vision of the hospital's mission and teamwork, and a strategic plan was drawn up that is still being implemented.

Chile↗
PubMed1998

Temporal aspects of slant and inclination perception.

Linear transformations (shear or scale transformations) of either horizontal or vertical disparity give rise to the percept of slant or inclination. It has been proposed that the percept of slant induced by vertical size disparity, known as Ogle's induced-size effect, and the analogous induced-shear effect, compensate for scale and shear distortions arising from aniseikonia, eccentric viewing, and cyclodisparity. We hypothesised that these linear transformations of vertical disparity are processed more slowly than equivalent transformations of horizontal disparity (horizontal shear and size disparity). We studied the temporal properties of the stereoscopic slant and inclination percepts that arose when subjects viewed stereograms with various combinations of horizontal and vertical size or shear disparities. We found no evidence to support our hypothesis. There were no clear differences in the build-up of percepts of slant or inclination induced by step changes in horizontal size or shear disparity and those induced by step changes in vertical size or shear disparity. Perceived slant and inclination decreased in a similar manner with increasing temporal frequency for modulations of transformations of both horizontal and vertical disparity. Considerable individual differences were found and several subjects experienced slant reversal, particularly with oscillating stimuli. An interesting finding was that perceived slant induced by modulations of dilation disparity was in the direction of the vertical component. This suggests the vertical size disparity mechanism has a higher temporal bandwidth than the horizontal size disparity mechanism. However, conflicting perspective information may play a dominant role in determining the temporal properties of perceived slant and inclination.

Form Perception↗
PubMed2004

Corneal and lenticular components of total astigmatism in a preschool sample.

PURPOSE: To examine the contribution of corneal and lenticular components to total astigmatism in preschool low and high astigmats to determine whether there was any compensation for high astigmatism by the lenticular component. METHODS: Cycloplegic refractive and keratometric measures using the Retinomax K-Plus (Nikon Inc., Melville, NY) were conducted on 129 children (mean age, 51.1 +/- 8.4 mo) in Oxford County, Canada. We divided the sample into high astigmats (total cylinder > or =1 D; mean, 1.38 +/- 0.43 D; n = 29) and normal astigmats (total cylinder < or =0.75 D; mean, 0.22 +/- 0.20 D; n = 100). Measures of total and corneal cylinder were transposed into J0 and J45 components, where positive and negative J0 values quantified with-the-rule (WTR) and against-the-rule astigmatisms, respectively, and J45 quantified oblique astigmatism. RESULTS: WTR astigmatism was dominant in both the high and normal astigmatic group. J0 and J45 components of corneal astigmatism were highly correlated with total astigmatism in high astigmats, whereas only J0 was significantly correlated with total astigmatism in normal astigmats. Although the magnitude of total and corneal cylinder was significantly greater in high astigmats, overall lenticular cylinder was similar in both groups. However, the Fourier transforms showed high astigmats to have significantly lower lenticular J0 and higher lenticular J45 than the normal astigmats. CONCLUSIONS: Astigmatism in 3- to 5-year-old children is primarily corneal. In preschool children, the lens does not vary in response to high amounts of corneal WTR astigmatism, and in fact, it increases the oblique astigmatism component when the corneal component is high. In high astigmats, lenticular astigmatism contributes to both J0 and J45 components, whereas the corneal contribution is primarily J0.

Astigmatism↗
PubMed1993

[Homeostasis, diabetes and cancer].

There is a large body of evidence to consider that the functional aspects of the metabolism of the cancer cell and hypoinsulinemic diabetes mellitus dwell at both ends of a biochemico-metabolic spectrum representing two opposite homeostatic and pathological tendencies. Furthermore, an initial homeostatic approach based up the acid-base balance and/or its hydrogen ion dynamics, systematically considered at multiple dimensions of knowledge and in different areas and fields of biomedical research, allows to reach a systematic vision and an all-comprehensive and hierarchically organized perspective for the integrated study of both malignant and non-malignant, as well as diabetic, metabolism, while at the same time opens new avenues reaching out towards a better understanding of both the etiopathogenesis of certain epithelial tumors and the chronic complications of diabetes mellitus. Besides, such a unitarian outlook may very well open new ways towards a more comprehensive understanding of the interrelationships among both degenerative processes, and from the bioenergetic to the clinical levels, hopefully leading to better preventive and treatment strategies.

Alkalosis↗
PubMed1994

Viewpoint--invariance of contour-curvature discrimination over extended performance levels.

A traditional approach to the problem of human object recognition is to assume that the visual system represents an object in terms of invariant quantities. This study considers a generalization of this approach to the problem of visually recognizing differences in shape, specifically between contour markings on a planar surface, as the position of the surface varies in space. For a given 'shape cue', perceived differences in contour may be quantified by threshold values--Weber fractions--at a particular criterion level of performance. A necessary theoretical condition for the Weber fraction to be constant with the relative viewpoint of the observer is that the cue should be a relative invariant under the natural spatial transformations of the image. Some data are reviewed showing how statistically efficient some cues are in explaining the observed discriminability of symmetric curved contours at a fixed criterion performance level of 75%. A new, fuller analysis is presented showing that the efficiency of the most efficient cue satisfying the invariance condition is maintained over a wide range of criterion performance levels, from 53% to 92% correct, corresponding to discrimination index values of 0.1 to 2.0. Over these levels, Weber's law was found empirically to hold almost exactly.

Animals↗
PubMed1993

Factor analysis and computerized EEG: preliminary data on schizophrenic patients.

Factor Analysis can extract salient features from EEG data and reduce redundancy of multi-channel computerized EEG data. A 16-channel computerized frequency analysis of background brain electrical activity during 3 functional conditions (eyes closed, eyes open and hyperventilation) was carried out in two groups, fifty healthy subjects and twenty-three schizophrenics. The power log-transformed relative values of normal subjects and schizophrenic patients were submitted to Factor Analysis and the resulting factor scores were compared. Schizophrenics showed EEG abnormalities in delta 2, theta 1 and alpha 2 bands for the first factor, accounting for the eyes closed condition, and in theta 2 and beta 2 bands for the second factor, accounting for the eyes open condition. This preliminary study demonstrates the utility of Factor Analysis in managing and comparing computerized EEG data.

Adult↗
PubMed2006

Dark adaptation of human rod bipolar cells measured from the b-wave of the scotopic electroretinogram.

To examine the dark adaptation of human rod bipolar cells in vivo, we recorded ganzfeld ERGs to (a) a family of flashes of increasing intensity, (b) dim test flashes presented on a range of background intensities, and (c) dim test flashes presented before, and up to 40 min after, exposure to intense illumination eliciting bleaches from a few per cent to near total. The dim flash ERG was characterized by a prominent b-wave response generated principally by rod bipolar cells. In the presence of background illumination the response reached peak earlier and desensitized according to Weber's Law. Following bleaching exposures, the response was initially greatly desensitized, but thereafter recovered slowly with time. For small bleaches, the desensitization was accompanied by acceleration, in much the same way as for real light. Following a near-total bleach, the response was unrecordable for >10 min, but after approximately 23 min half-maximal sensitivity was reached, and full sensitivity was restored between approximately 35 and 40 min. With smaller bleaches, recovery commenced earlier. We converted the post-bleach measurements of desensitization into 'equivalent background intensities' using a Crawford transformation. Across the range of bleaching levels, the results were described by a prominent 'S2' component (0.24 decades min(-1)) together with a smaller and slower 'S3' component (0.06 decades min(-1)), as is found for dark adaptation of the scotopic visual system. We attribute the S2 component to the presence of unregenerated opsin, and we speculate that the S3 component results from ion channel closure by all-trans retinal.

Adaptation, Ocular↗
PubMed1996

Extracellular regulators and pattern formation in the developing Drosophila retina.

The compound eye of Drosophila melanogaster is composed of about 800 similar facets (or ommatidia) each of which contains 20 cells (8 photoreceptor neurons and 12 accessory cells). The fly's vision depends on the precise geometry of these components, and the developmental systems that produce pattern and cell fate have become models for nervous system development in general. The development of this pattern is progressive and appears to involve several levels of induction and inhibition, mediated by diffusible signals. The analysis of genes identified by mutation has revealed that several diffusible factors act in the early patterning steps of the eye. Genes that encode these factors include hedgehog, decapentaplegic, wingless, spitz and scabrous.

Animals↗
PubMed2000

Comprehensive integrated primary mental health care for South Africa. Pipedream or possibility?

While the vision for restructuring health care in South Africa is based on a comprehensive primary health care system, care at the primary level remains largely biomedical in orientation. Given this, I argue that whilst adding mental health care to primary level care may increase accessibility of psychiatric care. it will not, however, provide for comprehensive integrated primary mental health care as planned. This would require a paradigm shift towards a comprehensive discourse of care which includes mental health care. While efforts towards reorienting health care personnel in South Africa towards the primary health care approach have been initiated, an examination of the primary health care system in one sub-district in South Africa, reveals that the delivery of biomedical care is sustained by a number of factors within the primary health care system as well as within the macro-context. A shift in the paradigm of care provided would therefore require the transformation of the system on many fronts. Of central importance would be the restructuring of the primary health care system to be supportive of emotional labour, health promotion, empowerment of service users and of care which takes the subjectivity of the illness experience for the patient into account.

Culture↗
PubMed1996

A model of multiplicative neural responses in parietal cortex.

Visual responses of neurons in parietal area 7a are modulated by a combined eye and head position signal in a multiplicative manner. Neurons with multiplicative responses can act as powerful computational elements in neural networks. In the case of parietal cortex, multiplicative gain modulation appears to play a crucial role in the transformation of object locations from retinal to body-centered coordinates. It has proven difficult to uncover single-neuron mechanisms that account for neuronal multiplication. Here we show that multiplicative responses can arise in a network model through population effects. Specifically, neurons in a recurrently connected network with excitatory connections between similarly tuned neurons and inhibitory connections between differently tuned neurons can perform a product operation on additive synaptic inputs. The results suggest that parietal responses may be based on this architecture.

Animals↗
PubMed1992

Health care and AIDS.

The acquired immune deficiency syndrome (AIDS) is a harbinger for change in health care. There are many powerful forces poised to transform the industrialized health care structure of the twentieth century, and AIDS may act as either a catalyst or an amplifier for these forces. AIDS could, for example, swamp local resources and thereby help trigger national reform in a health care system that has already lost public confidence. AIDS can also hasten the paradigm shift that is occurring throughout health care. Many of the choices society will confront when dealing with AIDS carry implications beyond health care. Information about who has the disease, for example, already pits traditional individual rights against group interests. Future information systems could make discrimination based upon medical records a nightmare for a growing number of individuals. Yet these systems also offer the hope of accelerated progress against not only AIDS but other major health threats as well. The policy choices that will define society's response to AIDS can best be made in the context of a clearly articulated vision of a society that reflects our deepest values.

Acquired Immunodeficiency Syndrome↗
PubMed2007

[Signal reception and processing by the retina].

Phototransduction occurs in the retina, which, as an outsourced part of the brain, fulfills important tasks in neuronal processing for image analysis relevant to perception. Interlinked biochemical cycles with immense amplification factors transform the electromagnetic waves of light into neuronal activity, and photochemical adaptation allows adjustment to light intensities of over more than 10 logarithmic units. Beginning with its dual system of photoreceptors with highly sensible rods and a color sensitive cone system, the retina, with between 50 and 100 main cell types, is characterized by complex neuronal circuits. The resulting center-surround antagonism of the receptive fields serves, amongst other things, to amplify intensity and color contrasts. Specialized ganglion cell types give rise to parallel signaling pathways into the higher visual centers of the brain.

Humans↗
PubMed1984

Monomorphous plurihormonal adenoma of the human pituitary. A histologic, immunocytologic and ultrastructural study.

A well-developed 23-year-old man, complaining of blurred vision but with no endocrine symptoms, was found to have a large pituitary adenoma spreading outside the sella. Endocrine investigations disclosed growth hormone deficiency, hyperprolactinemia (responsive to thyrotropin-releasing hormone), and very high blood alpha-subunit (72 ng/ml) level. Histology showed a chromophobic, slightly acidophilic pituitary adenoma with focal fibrosis and calcification. The immunoperoxidase technique revealed prolactin and alpha-subunit in the cytoplasm of a single-cell type, at the light and electron microscopic level, indicating that monomorphous, plurihormonal adenomas exist in the human pituitary. Immunostaining with antibodies raised against beta-thyroid stimulating hormone, beta-follicle stimulating hormone and alpha-endorphin were observed in scattered cells. Those cells that contained immunoreactive alpha-endorphin did not appear to contain alpha-subunit. The ultrastructural features of adenoma cells showed no resemblance to any known cells in nontumorous or tumorous pituitaries. It can be postulated that adenohypophysial cells, after neoplastic transformation, may have the ability to secrete a number of biochemically unrelated hormones, suggesting that during embryologic development they pass through a common progenitor cell stage, capable of plurihormonal activity.

Adenoma↗
PubMed1980

A spatial perturbation technique for the investigation of discrete internal representations of visual patterns.

A technique is proposed for the investigation of discrete internal representations assumed to be formed by the visual system in response to pattern stimuli. The proposed technique involves applying a local L-parameter group of spatial transformations to a pattern to generate a "continuum" of patterns. The visual discriminability of pairs of perturbed patterns corresponding to small fixed increments in the transformation parameter is determined at various points in the parameter range. By means of a simple rule, the characteristics of this discrimination performance are then related to the probability density functions assumed to underlie the hypothesized discrete internal representations. Two experimental applications of the proposed technique are described. The first is concerned with a discrete internal representation involving the specification of the colinearity or noncolinearity of the points in a pattern; the second is concerned with a discrete internal representation involving the specification of the acuteness or obtuseness of the angle between two lines in a pattern.

Humans↗
PubMed1980

The posterior median eyes of the dinopid spider Menneus.

The posterior median (pm) eyes of the dinopid spider Menneus unifasciatus L. Koch are described and compared with the pm eyes of Dinopis, which are highly specialised for night vision. The lenses of Menneus have F-numbers of 0.72 compared to 0.58 in Dinopis, the distance between receptors is ca. 4.0 microns compared to 20-22 microns for Dinopis, and image quality is matched to receptor spacing. The lens of Menneus is simple, while that of Dinopis comprises two components of different refractive indices (Blest and Land 1977). Receptive segments of the pm eyes of Dinopis are hexagonal in transverse section and those of adjacent cells are tightly contiguous, allowing the possibility of both optical and electrical coupling (Blest 1978). Receptive segments of Menneus are separated from each other by glial processes containing little pigment, and each segment possesses two rhabdomeres on opposite faces of the cell. Rhabdomere volumes undergo a daily cycle similar to that described for Dinopis, but of relatively minor extent. It is shown that the pm eye of Dinopis could have evolved from that of Menneus by a simple series of transformations, and that a gain of two logarithmic units of sensitivity can be attributed to changes in optical design alone.

Animals↗