American Book Publishing Record Cumulative 1950-1977

Download American Book Publishing Record Cumulative 1950-1977 PDF Online Free

Author :
Publisher : R. R. Bowker
ISBN 13 :
Total Pages : 1446 pages
Book Rating : 4.3/5 (91 download)

DOWNLOAD NOW!


Book Synopsis American Book Publishing Record Cumulative 1950-1977 by : R.R. Bowker Company

Download or read book American Book Publishing Record Cumulative 1950-1977 written by R.R. Bowker Company and published by R. R. Bowker. This book was released on 1978 with total page 1446 pages. Available in PDF, EPUB and Kindle. Book excerpt:

American Book Publishing Record Cumulative, 1950-1977

Download American Book Publishing Record Cumulative, 1950-1977 PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 1454 pages
Book Rating : 4.4/5 (91 download)

DOWNLOAD NOW!


Book Synopsis American Book Publishing Record Cumulative, 1950-1977 by : R.R. Bowker Company. Department of Bibliography

Download or read book American Book Publishing Record Cumulative, 1950-1977 written by R.R. Bowker Company. Department of Bibliography and published by . This book was released on 1978 with total page 1454 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Foundations of Sport-Related Brain Injuries

Download Foundations of Sport-Related Brain Injuries PDF Online Free

Author :
Publisher : Springer Science & Business Media
ISBN 13 : 0387325654
Total Pages : 482 pages
Book Rating : 4.3/5 (873 download)

DOWNLOAD NOW!


Book Synopsis Foundations of Sport-Related Brain Injuries by : Semyon M. Slobounov

Download or read book Foundations of Sport-Related Brain Injuries written by Semyon M. Slobounov and published by Springer Science & Business Media. This book was released on 2006-08-25 with total page 482 pages. Available in PDF, EPUB and Kindle. Book excerpt: In summarizing current insights and controversies over concussions in athletics, this book makes the vital point that symptom resolution does not necessarily mean injury resolution. Research shows that dysfunctional pathways continue for extended periods even after a minor concussion. Until the consequences of short-term perturbations and long-term residual brain dysfunctions are better understood, concussions must be treated with respect and given a higher priority for continued research activity.

Secondary Schizophrenia

Download Secondary Schizophrenia PDF Online Free

Author :
Publisher : Cambridge University Press
ISBN 13 : 1139485229
Total Pages : pages
Book Rating : 4.1/5 (394 download)

DOWNLOAD NOW!


Book Synopsis Secondary Schizophrenia by : Perminder S. Sachdev

Download or read book Secondary Schizophrenia written by Perminder S. Sachdev and published by Cambridge University Press. This book was released on 2010-02-04 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Schizophrenia may not be a single disease, but the result of a diverse set of related conditions. Modern neuroscience is beginning to reveal some of the genetic and environmental underpinnings of schizophrenia; however, an approach less well travelled is to examine the medical disorders that produce symptoms resembling schizophrenia. This book is the first major attempt to bring together the diseases that produce what has been termed 'secondary schizophrenia'. International experts from diverse backgrounds ask the questions: does this medical disorder, or drug, or condition cause psychosis? If yes, does it resemble schizophrenia? What mechanisms form the basis of this relationship? What implications does this understanding have for aetiology and treatment? The answers are a feast for clinicians and researchers of psychosis and schizophrenia. They mark the next step in trying to meet the most important challenge to modern neuroscience – understanding and conquering this most mysterious of human diseases.

Neuroprosthetics and Brain-Computer Interfaces in Spinal Cord Injury

Download Neuroprosthetics and Brain-Computer Interfaces in Spinal Cord Injury PDF Online Free

Author :
Publisher : Springer Nature
ISBN 13 : 3030685454
Total Pages : 377 pages
Book Rating : 4.0/5 (36 download)

DOWNLOAD NOW!


Book Synopsis Neuroprosthetics and Brain-Computer Interfaces in Spinal Cord Injury by : Gernot Müller-Putz

Download or read book Neuroprosthetics and Brain-Computer Interfaces in Spinal Cord Injury written by Gernot Müller-Putz and published by Springer Nature. This book was released on 2021-04-26 with total page 377 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive overview of the current state of the art of practical applications of neuroprosthesis based on functional electrical stimulation for restoration of motor functions lost by spinal cord injury and discusses the use of brain-computer interfaces for their control. The book covers numerous topics starting with basics about spinal cord injury, electrical stimulation, electrical brain signals and brain-computer interfaces. It continues with an overview of neuroprosthetic solutions for different purposes and non-invasive and invasive brain-computer interface implementations and presents clinical use cases and practical applications of BCIs. Finally, the authors give an outlook on cutting edge research with a high potential for clinical translation in the near future. All authors committed themselves to use easy-to-understand language and to avoid very specific information, focusing instead on the essential aspects. This makes this book an ideal choice not only for researchers and clinicians at all stages of their education interested in the topic of brain-computer interface-controlled neuroprostheses, but also for end users and their caregivers who want to inform themselves about the current technological possibilities to improve paralyzed motor functions.

Movement Disorder Emergencies

Download Movement Disorder Emergencies PDF Online Free

Author :
Publisher : Springer Science & Business Media
ISBN 13 : 1592599028
Total Pages : 250 pages
Book Rating : 4.5/5 (925 download)

DOWNLOAD NOW!


Book Synopsis Movement Disorder Emergencies by : Steven J. Frucht

Download or read book Movement Disorder Emergencies written by Steven J. Frucht and published by Springer Science & Business Media. This book was released on 2008-02-10 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt: Movement Disorder Emergencies: Diagnosis and Treatment provides a fresh and unique approach to what is already a high-profile subspecialty area in clinical neurology. The disorders covered in this volume are standard fare in the field but emphasize the urgencies and emergencies that can occur. One of the very attractive features of the field of movement disorders is that diagnosis is often based on unique visible and sometimes audible phenomenological symptoms and signs. Therefore, in this era of highly sophisticated laboratory and radiological diagnostic tools, the diagnosis of many movement disorders is still largely made in the clinic where pattern recognition is key. Crucial to astute clinical diagnosis is broad clinical experience. In short, you have to have seen one to recognize one! Patients with movement disorders nearly always present as outpatients but, as aptly recognized by Drs. Frucht and Fahn, this may include acute manifestations leading to emergency presentations, often in an emergency room setting, where they are very likely to be unrecognized and therefore poorly managed. The authors define an “emergency” movement disorder as one in which failure to promptly diagnose and treat may result in significant morbidity or mortality. However, they also stress the importance of certain “can’t miss” diagnoses such as Wilson’s disease, dopa-responsive dystonia, and Whipple’s disease in which delayed diagnosis in less emergent situations can lead to slowly evolving and often irreversible neurological damage with tragic consequences.

Augmentation of Brain Function: Facts, Fiction and Controversy. Volume III: From Clinical Applications to Ethical Issues and Futuristic Ideas

Download Augmentation of Brain Function: Facts, Fiction and Controversy. Volume III: From Clinical Applications to Ethical Issues and Futuristic Ideas PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (136 download)

DOWNLOAD NOW!


Book Synopsis Augmentation of Brain Function: Facts, Fiction and Controversy. Volume III: From Clinical Applications to Ethical Issues and Futuristic Ideas by :

Download or read book Augmentation of Brain Function: Facts, Fiction and Controversy. Volume III: From Clinical Applications to Ethical Issues and Futuristic Ideas written by and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The final volume in this tripartite series on Brain Augmentation is entitled "From Clinical Applications to Ethical Issues and Futuristic Ideas". Many of the articles within this volume deal with translational efforts taking the results of experiments on laboratory animals and applying them to humans. In many cases, these interventions are intended to help people with disabilities in such a way so as to either restore or extend brain function. Traditionally, therapies in brain augmentation have included electrical and pharmacological techniques. In contrast, some of the techniques discussed in this volume add specificity by targeting select neural populations. This approach opens the door to where and how to promote the best interventions. Along the way, results have empowered the medical profession by expanding their understanding of brain function. Articles in this volume relate novel clinical solutions for a host of neurological and psychiatric conditions such as stroke, Parkinson's disease, Huntington's disease, epilepsy, dementia, Alzheimer's disease, autism spectrum disorders (ASD), traumatic brain injury, and disorders of consciousness. In disease, symptoms and signs denote a departure from normal function. Brain augmentation has now been used to target both the core symptoms that provide specificity in the diagnosis of a disease, as well as other constitutional symptoms that may greatly handicap the individual. The volume provides a report on the use of repetitive transcranial magnetic stimulation (rTMS) in ASD with reported improvements of core deficits (i.e., executive functions). TMS in this regard departs from the present-day trend towards symptomatic treatment that leaves unaltered the root cause of the condition. In diseases, such as schizophrenia, brain augmentation approaches hold promise to avoid lengthy pharmacological interventions that are usually riddled with side effects or those with limiting returns as in the case of Parkinson's disease. Brain stimulation can also be used to treat auditory verbal hallucination, visuospatial (hemispatial) neglect, and pain in patients suffering from multiple sclerosis. The brain acts as a telecommunication transceiver wherein different bandwidth of frequencies (brainwave oscillations) transmit information. Their baseline levels correlate with certain behavioral states. The proper integration of brain oscillations provides for the phenomenon of binding and central coherence. Brain augmentation may foster the normalization of brain oscillations in nervous system disorders. These techniques hold the promise of being applied remotely (under the supervision of medical personnel), thus overcoming the obstacle of travel in order to obtain healthcare. At present, traditional thinking would argue the possibility of synergism among different modalities of brain augmentation as a way of increasing their overall effectiveness and improving therapeutic selectivity. Thinking outside of the box would also provide for the implementation of brain-to-brain interfaces where techniques, proper to artificial intelligence, could allow us to surpass the limits of natural selection or enable communications between several individual brains sharing memories, or even a global brain capable of self-organization. Not all brains are created equal. Brain stimulation studies suggest large individual variability in response that may affect overall recovery/treatment, or modify desired effects of a given intervention. The subject's age, gender, hormonal levels may affect an individual's cortical excitability. In addition, this volume discusses the role of social interactions in the operations of augmenting technologies. Finally, augmenting methods could be applied to modulate consciousness, even though its neural mechanisms are poorly understood. Finally, this volume should be taken as a debate on social, moral and ethical issues on neurotechnologies. Brain enhancement may transform the individual into someone or something else. These techniques bypass the usual routes of accommodation to environmental exigencies that exalted our personal fortitude: learning, exercising, and diet. This will allow humans to preselect desired characteristics and realize consequent rewards without having to overcome adversity through more laborious means. The concern is that humans may be playing God, and the possibility of an expanding gap in social equity where brain enhancements may be selectively available to the wealthier individuals. These issues are discussed by a number of articles in this volume. Also discussed are the relationship between the diminishment and enhancement following the application of brain-augmenting technologies, the problem of "mind control" with BMI technologies, free will the duty to use cognitive enhancers in high-responsibility professions, determining the population of people in need of brain enhancement, informed public policy, cognitive biases, and the hype caused by the development of brain- augmenting approaches.

Biomechanics of the Brain

Download Biomechanics of the Brain PDF Online Free

Author :
Publisher : Springer
ISBN 13 : 3030049965
Total Pages : 353 pages
Book Rating : 4.0/5 (3 download)

DOWNLOAD NOW!


Book Synopsis Biomechanics of the Brain by : Karol Miller

Download or read book Biomechanics of the Brain written by Karol Miller and published by Springer. This book was released on 2019-08-08 with total page 353 pages. Available in PDF, EPUB and Kindle. Book excerpt: This new edition presents an authoritative account of the current state of brain biomechanics research for engineers, scientists and medical professionals. Since the first edition in 2011, this topic has unquestionably entered into the mainstream of biomechanical research. The book brings together leading scientists in the diverse fields of anatomy, neuroimaging, image-guided neurosurgery, brain injury, solid and fluid mechanics, mathematical modelling and computer simulation to paint an inclusive picture of the rapidly evolving field. Covering topics from brain anatomy and imaging to sophisticated methods of modeling brain injury and neurosurgery (including the most recent applications of biomechanics to treat epilepsy), to the cutting edge methods in analyzing cerebrospinal fluid and blood flow, this book is the comprehensive reference in the field. Experienced researchers as well as students will find this book useful.

Neurological Aspects of Spinal Cord Injury

Download Neurological Aspects of Spinal Cord Injury PDF Online Free

Author :
Publisher : Springer
ISBN 13 : 9783319834863
Total Pages : 0 pages
Book Rating : 4.8/5 (348 download)

DOWNLOAD NOW!


Book Synopsis Neurological Aspects of Spinal Cord Injury by : Norbert Weidner

Download or read book Neurological Aspects of Spinal Cord Injury written by Norbert Weidner and published by Springer. This book was released on 2018-06-12 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This clinically focused book aims to cover for the first time all of the neurological aspects relevant to the diagnosis and treatment of spinal cord disease. Furthermore, innovative neurorestorative therapeutic strategies - aiming for repair of the damaged spinal cord and/or reorganization of the remaining nervous system - with significant potential for translation into clinical routine are presented. The book covers a comprehensive list of topics, including epidemiology, neuroanatomy, etiology of compressive and non-compressive spinal cord injury, imaging, neurophysiology, neurological sequelae, and complications with emphasis on dysfunction of the autonomic nervous system. Both clinically established and preclinical therapies are discussed in detail. The book is suited for trainees and practicing clinicians including neurologists, spine surgeons, rehabilitation specialists, neuroradiologists, and occupational/physical therapists; it will also be of value to neuroscientists involved in research into spinal cord disease.

EEG Signal Processing

Download EEG Signal Processing PDF Online Free

Author :
Publisher : John Wiley & Sons
ISBN 13 : 1118691237
Total Pages : 312 pages
Book Rating : 4.1/5 (186 download)

DOWNLOAD NOW!


Book Synopsis EEG Signal Processing by : Saeid Sanei

Download or read book EEG Signal Processing written by Saeid Sanei and published by John Wiley & Sons. This book was released on 2013-05-28 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt: Electroencephalograms (EEGs) are becoming increasingly important measurements of brain activity and they have great potential for the diagnosis and treatment of mental and brain diseases and abnormalities. With appropriate interpretation methods they are emerging as a key methodology to satisfy the increasing global demand for more affordable and effective clinical and healthcare services. Developing and understanding advanced signal processing techniques for the analysis of EEG signals is crucial in the area of biomedical research. This book focuses on these techniques, providing expansive coverage of algorithms and tools from the field of digital signal processing. It discusses their applications to medical data, using graphs and topographic images to show simulation results that assess the efficacy of the methods. Additionally, expect to find: explanations of the significance of EEG signal analysis and processing (with examples) and a useful theoretical and mathematical background for the analysis and processing of EEG signals; an exploration of normal and abnormal EEGs, neurological symptoms and diagnostic information, and representations of the EEGs; reviews of theoretical approaches in EEG modelling, such as restoration, enhancement, segmentation, and the removal of different internal and external artefacts from the EEG and ERP (event-related potential) signals; coverage of major abnormalities such as seizure, and mental illnesses such as dementia, schizophrenia, and Alzheimer’s disease, together with their mathematical interpretations from the EEG and ERP signals and sleep phenomenon; descriptions of nonlinear and adaptive digital signal processing techniques for abnormality detection, source localization and brain-computer interfacing using multi-channel EEG data with emphasis on non-invasive techniques, together with future topics for research in the area of EEG signal processing. The information within EEG Signal Processing has the potential to enhance the clinically-related information within EEG signals, thereby aiding physicians and ultimately providing more cost effective, efficient diagnostic tools. It will be beneficial to psychiatrists, neurophysiologists, engineers, and students or researchers in neurosciences. Undergraduate and postgraduate biomedical engineering students and postgraduate epileptology students will also find it a helpful reference.

Brain-Computer Interface Research

Download Brain-Computer Interface Research PDF Online Free

Author :
Publisher : Springer
ISBN 13 : 3319251902
Total Pages : 133 pages
Book Rating : 4.3/5 (192 download)

DOWNLOAD NOW!


Book Synopsis Brain-Computer Interface Research by : Christoph Guger

Download or read book Brain-Computer Interface Research written by Christoph Guger and published by Springer. This book was released on 2015-12-12 with total page 133 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes ten of the most promising brain-computer-interface (BCI) projects to have emerged in recent years. BCI research is developing quickly, with many new ideas, research groups, and improved technologies. BCIs enable people to communicate just by thinking – without any movement at all. Several different groups have helped severely disabled users communicate with BCIs, and BCI technology is also being extended to facilitate recovery from stroke, epilepsy, and other conditions. Each year, hundreds of the top BCI scientists, engineers, doctors, and other visionaries compete for the most prestigious honor in the BCI research community: the annual BCI Award. The 2014 BCI Award competition was again competitive, with 69 research groups vying for a nomination. This book summarizes the 2014 BCI Award, including the ten projects that were nominated, the winner, and analyses and discussions of the submitted projects and how they reflect general trends in BCI development. Each of these ten groups provides a chapter summarizing their nominated project, including an introduction, description of methods, results, and newer work completed after the project was submitted. Hence, this book provides a cutting-edge overview of the newest BCI research trends, from top groups, in an easy to read format with numerous supporting pictures, graphs, and figures.

Brain Death

Download Brain Death PDF Online Free

Author :
Publisher : Springer Science & Business Media
ISBN 13 : 0387389776
Total Pages : 237 pages
Book Rating : 4.3/5 (873 download)

DOWNLOAD NOW!


Book Synopsis Brain Death by : C. Machado

Download or read book Brain Death written by C. Machado and published by Springer Science & Business Media. This book was released on 2007-09-10 with total page 237 pages. Available in PDF, EPUB and Kindle. Book excerpt: This text provides an overview of the processes of brain death, exploring the concepts and historical approach of human death, clinical examinations of brain-dead patients, ancillary tests in coma and brain death, bioethical discussions of brain death and its relationship with some consciousness disturbances, and the legal considerations of human death. Unlike other, narrow-focus reference this book encompasses a wide spectrum of issues including medical, legal, bioethical and historical aspects.

Recent Advances in Biological Psychiatry

Download Recent Advances in Biological Psychiatry PDF Online Free

Author :
Publisher : Springer
ISBN 13 : 1489973133
Total Pages : 357 pages
Book Rating : 4.4/5 (899 download)

DOWNLOAD NOW!


Book Synopsis Recent Advances in Biological Psychiatry by : Joseph Wortis

Download or read book Recent Advances in Biological Psychiatry written by Joseph Wortis and published by Springer. This book was released on 2013-12-11 with total page 357 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Psychoanalysis and Neuroscience

Download Psychoanalysis and Neuroscience PDF Online Free

Author :
Publisher : Springer Science & Business Media
ISBN 13 : 8847005507
Total Pages : 433 pages
Book Rating : 4.8/5 (47 download)

DOWNLOAD NOW!


Book Synopsis Psychoanalysis and Neuroscience by : Mauro Mancia

Download or read book Psychoanalysis and Neuroscience written by Mauro Mancia and published by Springer Science & Business Media. This book was released on 2007-04-29 with total page 433 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent scientific studies have brought significant advances in the understanding of basic mental functions such as memory, dreams, identification, repression, which constitute the basis of the psychoanalytical theory. This book focuses on the possibility of interactions between psychoanalysis and neuroscience: emotions and the right hemisphere, serotonin and depression. It is a unique tool for professionals and students in these fields, and for operators of allied disciplines, such as psychology and psychotherapy.

Peripheral Nerve Lesions

Download Peripheral Nerve Lesions PDF Online Free

Author :
Publisher : Springer Science & Business Media
ISBN 13 : 3642756115
Total Pages : 482 pages
Book Rating : 4.6/5 (427 download)

DOWNLOAD NOW!


Book Synopsis Peripheral Nerve Lesions by : M. Samii

Download or read book Peripheral Nerve Lesions written by M. Samii and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 482 pages. Available in PDF, EPUB and Kindle. Book excerpt: The introduction of the operating microscope as a surgical tool revolutionized the treatment of peripheral nerve lesions. A new era thus began in the early 1960s, which led to a substantial improvement in the management of nerve lesions. The results of nerve grafting techniques have demonstrated that, independent of the length of the defect, lesions can be successfully bridged. The free tissue transplants with microvascular anastomosis have also opened new, rewarding possibilities for peripheral nerve reconstruction procedures, facilitating the achievement not only of satisfactory anatomical but also of satisfactory fUhctional results. In order to evaluate the state of the art and reflect retrospectively on 25 years of microneurosurgical treatment of peripheral nerves, numerous outstanding scientists and clinicosurgical physicians were invited to Hanover in order to exchange their viewpoints and experiences. An active und fruitful discussion resulted which dealt with the many aspects of anatomy, pathology, clinical and neuro physiology, diagnosis, and with the surgery and physiotherapy which constitute modern-day peripheral nerve lesion treatment. The excit ing ongoing experimental and clinical activities have led us to support the wish and idea to publish the scientific exchange which took place during the Hanover symposium. I truly believe that the articles presented in this book cover so many interesting subjects concerned with peripheral nerve lesions that the book will serve the interested and dedicated physician involved with such cases as a reference work for the basics and also provide him with the therapeutic guidelines to assist him in his daily work.

Implantable Neural Prostheses 1

Download Implantable Neural Prostheses 1 PDF Online Free

Author :
Publisher : Springer Science & Business Media
ISBN 13 : 0387772618
Total Pages : 391 pages
Book Rating : 4.3/5 (877 download)

DOWNLOAD NOW!


Book Synopsis Implantable Neural Prostheses 1 by : David Zhou

Download or read book Implantable Neural Prostheses 1 written by David Zhou and published by Springer Science & Business Media. This book was released on 2009-06-10 with total page 391 pages. Available in PDF, EPUB and Kindle. Book excerpt: Significant progress has been made in the development of neural prostheses to restore human functions and improve the quality of human life. Biomedical engineers and neuroscientists around the world are working to improve design and performance of existing devices and to develop novel devices for artificial vision, artificial limbs, and brain–machine interfaces. This book, Implantable Neural Prostheses 1: Devices and Applications,ispart one of a two-book series and describes state-of-the-art advances in techniques associated with implantable neural prosthetic devices and their applications. Devices covered include sensory prosthetic devices, such as visual implants, cochlear implants, auditory midbrain implants, and spinal cord stimulators. Motor prosthetic devices, such as deep brain stimulators, Bion microstimu- tors, the brain control and sensing interface, and cardiac electro-stimulation devices are also included. Progress in magnetic stimulation that may offer a non-invasive approach to prosthetic devices is introduced. Regulatory approval of implantable medical devices in the United States and Europe is also discussed.

Modern Trends in Hypnosis

Download Modern Trends in Hypnosis PDF Online Free

Author :
Publisher : Springer Science & Business Media
ISBN 13 : 1468449133
Total Pages : 513 pages
Book Rating : 4.4/5 (684 download)

DOWNLOAD NOW!


Book Synopsis Modern Trends in Hypnosis by : David Waxman

Download or read book Modern Trends in Hypnosis written by David Waxman and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 513 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 9th International Congress of Hypnosis and Psychosomatic Medicine expresses the continuity in the effort to gain scientific knowledge of hypnosis and scientific status for it, ever since the 1st International Congress for Experimental and Therapeutic Hypnotism was held in Paris in 1889, attended by many of the best-remembered psychiatrists and psychologists of the day - men such as Babinski, Bernheim, Binet, Delboeuf, Freud, James, Lombroso, F. W. H. Myers, Ribot, and many others. The continuity was broken by the period of reduced interest in hypnosis between the time of the 2nd Inter national Congress for Hypnotism in Paris in 1900, and the revival of interest shown by the 3rd International Congress for Hypnosis and Psychosomatic Medicine in Paris in 1965. Since then, the Congresses have met more regularly, making the one of which this is the report, the 9th. The programs of these Congresses have become increasingly rich through the years, with many of the older problems still with us but now studied more dispassionately in the light of new knowledge and new scientific methods in the design of investigations and the vali dation of scientific findings.