Informed consent has become the most obvious instantiation of patient autonomy in contemporary medicine, though as a practice it does not encompass all spheres of medicine. While diagnostic radiological procedures carry some risk due to the use of radiation, there is no standardized practice of informed consent in the United States. The authors describe the ethical justification of informed consent, the legal background surrounding it, and a brief history of radiology and radiological protection. They ultimately argue that informed consent should (...) become a common practice in computed tomography given the risks involved due to radiation exposure, especially considering the overuse of this technology, since it respects patient autonomy. (shrink)

IntroductionDeep brain stimulation is an effective treatment for advanced Parkinson’s disease with the targeting bilateral subthalamic nucleus or globus pallidus internus. So far, detailed studies on the efficacy of unilateral STN-DBS for motor symptoms have been reported, but few studies have been conducted on unilateral GPi-DBS.Materials and MethodsSeventeen patients with Parkinson’s disease who underwent unilateral GPi-DBS were selected. We conducted comparison analyses between scores obtained 6–42 months pre- and postoperatively using the following measurement tools: the Movement Disorder Society Unified Parkinson’s (...) Disease Rating Scale part III, the Hoehn and Yahr stage, the presence/absence of dyskinesia, Mini-Mental State Examination, Frontal Assessment Battery, Geriatric Depression Scale, levodopa equivalent dose, and cerebral blood flow by single photon emission computed tomography. Patient backgrounds were compared between four cohorts with favorable and unfavorable postoperative outcome.ResultsSignificant improvement was observed postoperatively in the following: total MDS-UPDRS Part III scores during the off period, contralateral scores, ipsilateral scores, and axial scores. Similarly, the Hoehn and Yahr stages during the off period, and GDS also showed significant decrease. In contrast, LED, MMSE, and FAB remained unchanged while the number of patients who scored positive for dyskinesia decreased by 40%. Abnormal cerebral blood flow preoperatively seen in the cerebral cortex had normalized in the total score-based good responder cohort. In the ipsilateral score-based good responder cohort, cerebral blood flow increased in the contralateral frontal lobe including in the premotor cortex, contralateral to the DBS. Compared to the poor responders, postoperative good responders demonstrated significantly higher preoperative MMSE scores.DiscussionUnilateral GPi-DBS therapy was effective in improving contralateral, ipsilateral, and axial motor symptoms of patients with advanced PD; in particular, it was found to be especially beneficial in PwPD whose cognitive function was unimpaired; the treatment efficacy rivaled that of bilateral counterparts up till at least 6 months postoperatively. Finally, normalization of preoperative abnormalities in cerebral blood flow and increased cerebral blood flow in the contralateral frontal lobe indicated the beneficial potential of this therapy on ipsilateral motor symptoms. (shrink)

Preoperative diagnosis of gastric cancer and primary gastric lymphoma is challenging and has important clinical significance. Inspired by the inductive reasoning learning of the human brain, transfer learning can improve diagnosis performance of target task by utilizing the knowledge learned from the other domains (source domain). However, most studies focus on single-source transfer learning and may lead to model performance degradation when a large domain shift exists between the single-source domain and target domain. By simulating the multi-modal information learning and (...) transfer mechanism of human brain, this study designed a multisource transfer learning feature extraction and classification framework, which can enhance the prediction performance of the target model by using multisource medical data (domain). First, this manuscript designs a feature extraction network that takes the maximum mean difference based on the Wasserstein distance as an adaptive measure of probability distribution and extracts the domain-specific invariant representations between source and target domain data. Then, aiming at the random generation of parameters bringing uncertainties to prediction accuracy and generalization ability of extreme learning machine network, the 1-norm regularization is used to implement sparse constraints of the output weight matrix and improve the robustness of the model. Finally, some experiments are carried out on the data of two medical centers. The experimental results show that the area under curves (AUCs) of the method are 0.958 and 0.929 in the two validation cohorts, respectively. The method in this manuscript can provide doctors with a better diagnostic reference, which has certain practical significance. (shrink)

This paper aims to trace individual as well as collective aspects of ‘sight styles’ in diagnostic computed tomography. Radiologists need to efficiently translate the visualized data from the living human body into a reliable and significant diagnosis. During this process, their visual thinking and the created images are incorporated into a complex network of other visualizations, communication strategies, professional traditions, and (tacit) visual knowledge. To investigate the interplay of collective as well as individual dimensions of diagnostic seeing, the (...) concept of ‘sight collective’ (Sehkollektiv) is developed. On the one hand, this concept is based on critical reading of Ludwik Fleck’s epistemological writings and his notions of thought collective (Denkkollektiv) and thought style (Denkstil). On the other hand, it is tested by means of qualitative empirical studies in a radiological university clinic (participatory observations and informal interviews). By employing this approach, the paper traces the collective foundations of a certain diagnostic sight. Moreover, it shows how the individual abilities of radiologists to perform stylized seeing rely remarkably on software-based interactions with the processed images and on tacit dimensions of visual knowledge. (shrink)

Transfer learning can improve the robustness of deep learning in the case of small samples. However, when the semantic difference between the source domain data and the target domain data is large, transfer learning easily introduces redundant features and leads to negative transfer. According the mechanism of the human brain focusing on effective features while ignoring redundant features in recognition tasks, a brain-like classification method based on adaptive feature matching dual-source domain heterogeneous transfer learning is proposed for the preoperative aided (...) diagnosis of lung granuloma and lung adenocarcinoma for patients with solitary pulmonary solid nodule in the case of small samples. The method includes two parts: (1) feature extraction and (2) feature classification. In the feature extraction part, first, By simulating the feature selection mechanism of the human brain in the process of drawing inferences about other cases from one instance, an adaptive selected-based dual-source domain feature matching network is proposed to determine the matching weight of each pair of feature maps and each pair of convolution layers between the two source networks and the target network, respectively. These two weights can, respectively, adaptive select the features in the source network that are conducive to the learning of the target task, and the destination of feature transfer to improve the robustness of the target network. Meanwhile, a target network based on diverse branch block is proposed, which made the target network have different receptive fields and complex paths to further improve the feature expression ability of the target network. Second, the convolution kernel of the target network is used as the feature extractor to extract features. In the feature classification part, an ensemble classifier based on sparse Bayesian extreme learning machine is proposed that can automatically decide how to combine the output of base classifiers to improve the classification performance. Finally, the experimental results (the AUCs were 0.9542 and 0.9356, respectively) on the data of two center data show that this method can provide a better diagnostic reference for doctors. (shrink)

During the past decade, screening tests using computed tomography have disseminated into practice and been marketed to patients despite neither conclusive evidence nor professional agreement about their efficacy and cost-effectiveness at the population level. This phenomenon raises questions about physicians' professional roles and responsibilities within the setting of medical innovation, as well as the appropriate scope of patient autonomy and access to unproven screening technology. This article explores how physicians ought to respond when new screening examinations that lack (...) conclusive evidence of overall population benefit emerge in the marketplace and are requested by individual patients. To this end, the article considers the nature of evidence and how it influences decision-making for screening at both the public policy and individual patient levels. We distinguish medical and ethical differences between screening recommended for a population and screening considered on an individual patient basis. Finally, we discuss specific cases to explore how evidence, patient risk factors and preferences, and physician judgment ought to balance when making individual patient screening decisions. (shrink)

New technologies can upset scientific workplaces’ established practices and social order. Scientists may therefore prefer preserving skilled manual work and the social status quo to revolutionary technological change. For example, digital imaging of rock-encased fossils is a valuable way for scientists to “see” a specimen without traditional rock removal. However, interviews in vertebrate paleontology laboratories reveal workers’ skepticism toward computed tomography imaging. Scientists criticize replacing physical fossils with digital images because, they say, images are more subjective than the (...) “real thing.” I argue that these scientists are also implicitly supporting rock-removal technicians, who are skilled and trusted experts whose work would be made obsolete by widespread implementation of CT scanning. Scientists’ view of CT as a sometimes useful tool rather than a universal new approach to accessing fossils preserves the laboratory community’s social structure. Specifically, by privileging “real” specimens and trusted specimen-processing technicians over images and imaging experts, scientists preserve the lab community’s division of labor and skill, hierarchy between scientists and technicians, and these groups’ identity and mutual trust. (shrink)

Technology has outpaced the capacity of researchers performing research on human participants to interpret all data generated and handle those data responsibly. This poses a critical challenge to existing rules governing human subjects research. The technologies used in research to generate images, scans, and data can now produce so much information that there is significant potential for incidental findings, findings generated in the course of research but beyond the aims of the study. Neuroimaging scans may visualize the entire brain and (...) even the entire head; computed tomography colonography research may visualize the entire torso, from the base of the lungs to the pubis; genetics studies may reveal “extra” and sometimes unwanted information about the family, such as misattributed paternity and undisclosed adoption; and genomic microarray research increasingly involves whole-genome analysis revealing an individual’s complete genotype, with enormous potential for uncovering unexpected information about an individual’s genetics and risks of developing future conditions. (shrink)

ObjectivesTo simulate hemodynamic changes after extraluminal compression in pulsatile tinnitus patients with a prominent transverse-sigmoid sinus junction.MethodsOne patient-specific case was reconstructed based on computed tomography venography images of a PT patient. The compression degree served as a new index in this study. Cases with 10, 20, 30, 40, 50, 60, 70, 80, and 90% of the compression degree of the control subject were constructed. Steady-state computational fluid dynamics were assessed. The wall pressure distribution, wall maximum pressure and flow (...) pattern of the PTSJ were calculated to evaluate hemodynamic differences among all cases.ResultsWith increasing compression, the wall pressure at the compression point and downstream of the PTSJ decreased but increased upstream. When the compression degree exceeded 70%, the upstream pressure increased significantly. Above 50% compression, the blood flow pattern downstream of the sigmoid sinus tended to spiral, especially after 80% compression. Beyond 60% compression, the blood flow pattern under the compression axis became more medial.ConclusionMechanical compression of PTSJ changes wall pressure and blood flow patterns. The degree of compression should be carefully observed to avoid possible complications or reoccurrence. (shrink)

Today, advances in medicine and biotechnology occur at a rapid pace and have a profound impact on our lives. Mechanical devices can sustain an injured person's life indefinitely. Computed tomography (CT) and magnetic resonance imaging (MRI) scans of the body and brain can reveal disorders before symptoms appear. Genetic testing of embryos can predict whether people will have diseases earlier or later in life. It may even become possible to clone human beings. These and other developments raise difficult (...) ethical questions. Biomedical Ethics is an engaging philosophical introduction to the most important ethical positions and arguments in six areas of biomedicine: the patient-doctor relationship, medical research on humans, reproductive rights and technologies, genetics, medical decisions at the end of life, and the allocation of scarce medical resources. Concisely capturing the historical, contemporary, and future-oriented aspects of the field, author Walter Glannon discusses both perennial issues in medicine, such as doctors' duties to patients, and recent and emerging issues in scientific innovation, including gene therapy and cloning. Ideal for undergraduate courses in contemporary moral problems, introduction to ethics, and introduction to bioethics, Biomedical Ethics is accessible to students who have little or no background in ethical theory, medicine, or biotechnology. (shrink)

The ongoing coronavirus 2019 pandemic caused by the severe acute respiratory syndrome coronavirus 2 has resulted in a severe ramification on the global healthcare system, principally because of its easy transmission and the extended period of the virus survival on contaminated surfaces. With the advances in computer-aided diagnosis and artificial intelligence, this paper presents the application of deep learning and adversarial network for the automatic identification of COVID-19 pneumonia in computed tomography scans of the lungs. The complexity and (...) time limitation of the reverse transcription-polymerase chain reaction swab test makes it disadvantageous to depend solely on as COVID-19’s central diagnostic mechanism. Since CT imaging systems are of low cost and widely available, we demonstrate that the drawback of the RT-PCR can be alleviated with a faster, automated, and reduced contact diagnostic process via the use of a neural network model for the classification of infected and noninfected CT scans. In our proposed model, we explore the benefit of transfer learning as a means of resolving the problem of inadequate dataset and the importance of semisupervised generative adversarial network for the extraction of well-mapped features and generation of image data. Our experimental evaluation indicates that the proposed semisupervised model achieves reliable classification, taking advantage of the reflective loss distance between the real data sample space and the generated data. (shrink)

The chapters published in this volume developed from presentations, and their associated discussions at a conference organised by the Scottish Branch of the British Psychological Society, held at Rothesay, Isle of Bute, Scotland in September 1987. The goal of the conference was to bring together workers across a wide area of neuropsychological research to discuss recent technological advances, developments in assessment and rehabilitation, and to address theoretical issues of current interest. Thus, the chapters in this book include contributions on the (...) use of Magnetic Resonance Imaging and Single Photon Emission Computed Tomography in neuropsychological research, studies of hemi spheric specialisation and cooperation, alcoholic and Alzheimer type dementia, prosopagnosia and facial processing, the assessment, management and rehabilitation of memory problems, the assessment of premorbid intellectual status and issues in developmental neuropsychology. Many of those engaged in research and clinical practice in neuropsychology encounter a range of topic at least as wide as this in their professional lives. The opportunity for researchers and clinicians to discuss some of the key issues in the field was invaluable and we hope that readers gain as much from the material presented here as the participants did from the meeting itself. (shrink)

Concussion is a form of mild traumatic brain injury that can occur as a result of contact to the head or other parts of the body that causes a rapid acceleration-deceleration force to the brain that may cause a functional disturbance in an individual’s ability to concentrate or learn new information. Contrary to popular belief, it is not a bruise to the brain, and there is usually nothing detectable on standard imaging such as a computed tomography or magnetic (...) resonance imaging. Symptoms and signs are therefore important to detect and include decreased levels of consciousness, headache, nausea, difficulty concentrating, memory loss, and poor coordination. These signs and symptoms usually occur within minutes after the injury but may also appear several hours or even days later. (shrink)

Precise and timely diagnosis of Parkinson’s disease is important to control its progression among subjects. Currently, a neuroimaging technique called dopaminergic imaging that uses single photon emission computed tomography (SPECT) with 123I-Ioflupane is popular among clinicians for detecting Parkinson’s disease in early stages. Unlike other studies, which consider only low-level features like gray matter, white matter, or cerebrospinal fluid, this study explores the non-linear relation between different biomarkers (SPECT + biological) using deep learning and multivariate logistic regression. Striatal (...) binding ratios are obtained using 123I-Ioflupane SPECT scans from four brain regions which are further integrated with five biological biomarkers to increase the diagnostic accuracy. Experimental results indicate that this investigated approach can differentiate subjects with 100% accuracy. The obtained results outperform the ones reported in the literature. Furthermore, logistic regression model has been developed for estimating the Parkinson’s disease onset probability. Such models may aid clinicians in diagnosing this disease. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:My Ability to FlourishPaulette KoehlerIn twenty years of convulsions, I’ve never heard a neurologist mention the word “epilepsy.” Over this time, the intensity of my original simple partial seizures, “simple” signifying retained consciousness and “partial” indicating disturbances restricted to a specific area of my brain, grew to the complex level on my left temporal lobe. I believe this development was influenced by my use of prescribed medications. Several neurologists (...) from Los Angeles to San Francisco directed various electroencephalograms (EEGs), including a week–long, prescription–free EEG in the hospital; magnetic resonance imaging tests (MRIs); computed tomography (CT) scans anywhere from forty–five minutes to four hours each; and blood profiles to help determine my situation. For legal reasons, one neurologist even had me sign a release stating that he was not able to diagnose my situation.Test results present limited information about my brain and without ever saying, “I don’t know,” these neurologists communicated my test results by utilizing technical terms and thus not always answering my questions. After explaining that my head turns to the left while my right hand shakes, symptoms that have been recognized and reported by several friends and family members, my doctor replied that a seizure on the left side of my brain should cause my head to turn to the right and then changed the subject. I felt like asking, “Am I doing it wrong?”The brain is different from other parts of our anatomy in that it can’t be replaced like a kidney, heart or other organ. It cannot be removed like tonsils, an appendix or even a limb. It can be physically studied or repaired while functioning but the resulting percentage of survival or proper operation of the body after surgery is minimal and the number of people requiring such attention is so low that the amount is scanty. A dead brain limits the analysis of its functions.My “disabilities” involve spontaneous uncontrolled loss of consciousness, exhaustion, mood swings, and the suspension of driving privileges. Activity interference, extra naps, losing friends and not being able to get around are definite disadvantages. However, everyone needs to manage personal problems. No one is perfect.Public transit schedules and directions don’t always offer me the transportation I need. Fortunately, the combination of a bus ride with walking or running can serve my needs while also helping me to keep physically healthy.Limited benefits include discounted transit and the option to ride instead of walking or running. A trip to Nana’s on the train is always a treat.I’d rather not be branded “disabled” even though those who understand my situation address me with compassionate, sympathetic attention, [End Page E4] always asking how I physically feel. I feel fine. A seizure is only a quick, conscious loss of time and an occasional scrape on the knee. I’m more annoyed when I notice strangers looking suspiciously at my public transport discount card as if I don’t really deserve it.Like the “disability” brand, the medications I’ve taken, Dilantin, Neurontin, Depakote, Keppra and Lamictal, among others, all of which produced serious side effects without reducing the frequency of my seizures have only been a cover–up, preventing a search for the true cause and effective treatment of my seizures. Being identified as disabled has only limited my daily schedule. I am not disabled, as society has unfortunately characterized me.My seizures began in 1993, the year our FDA started approving rBGH, recombinant bovine growth hormone, man–made for the use on dairy cows to enhance their milk production. As a result, milk on the market increased while keeping the price from rising, as demonstrated in Economics I. Can the use of rBGH act on my brain in any way?One neurologist, in order to avoid the responsibility of inappropriate recommendations, presented his thoughts in the form of questions, encouraging me to consider options.“You’ve tried all of these medications?”“Has your diet alteration made any difference in your seizures?”“Have you tried organic foods?”His inquiries persuaded me to contemplate whether drugs are an answer to my problem, pay attention to differences in my life and... (shrink)

BackgroundThe prognosis of hypertensive intracerebral hemorrhage is poor at high altitudes. The objective of this study was to explore whether hyperbaric oxygen can improve the results of computed tomography perfusion imaging and the neurological function of patients with HICH, and influence the hemoglobin concentration.MethodThe patients with HICH were treated with puncture and drainage. Twenty-one patients were treated with HBO after the operation, and the other patients received conventional treatment. CTP was performed twice, and all indices were measured. Scatter (...) plots were used to determine the effect of hemoglobin concentration on CTP imaging. Receiver operating characteristic curves were plotted to analyze the effects of hemoglobin concentration and hematoma volume on recovery results. The patients were followed up for 6 months.ResultsForty-one patients with HICH were treated with puncture and drainage. In total, 21 were treated with HBO after the operation, and 20 received conventional treatment as the control group. No significant differences in the CBV and CBF values of the two groups were noted before treatment. After 10 days, the values of CBV and CBF in the HBO group were significantly higher than those in the control group. A scatter diagram showed there was no significant in the HBO group, but significant correlation for the CBV and CBF values in the control group’s hematoma center and margin. The ROC curves showed that hematoma volume had an influence on prognosis of the control group. The Glasgow Coma Scale scores of the HBO group were significantly higher than those of the control group.ConclusionsHBO therapy can improve the postoperative CBV and CBF values of patients with HICH and ameliorate their prognoses. There was no significant correlation between HBO group and hemoglobin concentration on admission. (shrink)

Incidental fndings of potential medical signifcance are seen in approximately 5-8 percent of asymptomatic subjects and 16 percent of symptomatic subjects participating in large computed tomography colonography studies, with the incidence varying further by CT acquisition technique. While most CTC research programs have a well-defned plan to detect and disclose IFs, such plans are largely communicated only verbally. Written consent documents should also inform subjects of how IFs of potential medical signifcance will be detected and reported in CTC (...) research studies. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Sweating the Small StuffTim CunninghamAs an emergency nurse, I often do not notice the small stressors as compared to the loads of intense physical and emotional suffering I witness while working at a level–one–trauma center. The horrendous deaths and injuries caused by gun violence, motorized vehicles, people in emotional distress and those suffering from chronic diseases build up on the mind as a veritable ‘scrapbook of nightmares.’ Emergency providers (...) know, in taking on this profession, that this is ‘all in a day’s work.’ Consequently, we put our selves at risk for emotional burnout as we bear witness to profound suffering while trying to improve lives.I see the traumas, the end–of–life decision making thrust upon families amidst a medical crisis and the other aspects of emergent suffering as bails of hay, against which I tried to build coping mechanisms in order to experience them but also be able to let go. For the most part I am confident to report that I have been able to work through major traumatic situations without belaboring the emotional residue. What I have failed to notice though are not the bails of hay, but individual straws of which they are made.A straw that nearly broke my back came to my pediatric emergency room as a 9–year–old girl who was involved in a low speed motor vehicle collision. She was restrained in the passenger seat; and although she was walking at the scene and crying, she was backboarded by EMS and placed in a cervical spine brace. On arrival to our emergency department she presented with normal vital signs and mutation. Her only complaint was diffuse abdominal pain. We preformed a FAST (Focused Assessment with Sonography for Trauma) exam, which was negative for free abdominal blood. Despite our efforts to make the patient comfortable, we were unable to ease her pain. The patient reported that her pain decreased after we took her off the backboard, but she still did not feel herself.Our attending and resident physicians decided that this child should have an abdominal computed tomography scan (CT) to rule out organ damage with subsequent bleeding. According to hospital protocol, this decision was within our standards of care. I stood by the family when the physician team discussed the plan of care and noticed the parents’ collective body language, which was troubled. I left the room with the physicians but not long after, the family subtly requested that I speak with them.The family was concerned about the radiation to which their child would be exposed. At the same time, they too were concerned about her abdominal pain and understood that a CT could confirm serious abdominal injury. They knew the gravity of the worst–case scenario and wanted to do what was best for their child.The mother asked me if this girl were my child what would I do.My first thought was: No CT, go home, watch her and return if symptoms worsen. My second thought conflicted with the first as I realized this was instruction that fell out of protocol differing from the opinions of the physician team. I paused before responding and found myself sputtering some pointless information about CT scans and mechanisms of injuries sustained from car accidents—I [End Page E9] was filling space, avoiding their question as I pondered the best answer.The girl’s parents told me that one was leaning towards the CT and the other against, they wanted my advice to make a decision. They pressed me saying, “What would you do.” Although I felt an uneasiness and nausea in that moment, I told them my truth, which was that I would go home without the CT.The family appeared relieved and I felt the sensation of stress leaving my body as if I had just taken a deep breath. Contented, but a daughter still with abdominal pain, the family left that evening with specific instructions to watch for adverse symptoms.In that moment, I felt like I had done the right thing but by the end of my shift I left work questioning my choice. I lost sleep that night because of... (shrink)

The proposed work describes an approach for the segmentation of abnormal lung CT scans of COVID-19. Lung diseases are the leading killer in both men and women. The pulmonary experts normally make attempts, such as early detection of patients by tomography tests before lung specialists treat patients who are tortured by lung disease. Moreover, lung specialists do their best to detect the presence of lung conditions. X rays or CT scan checks are performed for tomography tests. The finest (...) approach for medical diagnosis and a wide range of uses is computed tomography. This kind of imaging offers elaborate cross-sectional pictures of skinny slices of the organic structure. However, the preprocessing and denoising methods of Lung CT scans may mask some important image features. To address this challenge, we propose a novel framework involving an optimization technique algorithm to solve a multilevel thresholding problem based on information theory to segment abnormal lung CT scans. The proposed framework will evaluate a sample of CT scan images taken from a well-known benchmark database. The evaluation results will assess subjectively and objectively to demonstrate the effectiveness of the proposed framework. (shrink)

In “Body, Cyborgs and the Politics of Incarnation,” Bruno Latour recounts the story of Professor Paul Churchland, his colleague, carrying a portrait of his wife. “Nothing unusual in this,” Latour writes. “No, except that this picture was an image produced by computed tomography, a CT scan of his wife’s inner brain, in full colour”. The image of Professor Church-land proudly showing off a full-color CT of his wife’s beautiful brain has a wonderful sense of absurdity to it, and (...) its punch line depends on the reader being jolted by the strangeness of medical imagery standing in place of portraiture—no matter how stunning the cerebellum.However.. (shrink)

This article presents a case study of a recent controversy over the use of computed tomography as a diagnostic technology in South Korean hospitals. The controversy occurred in the wake of a series of conflicts in the late twentieth century over the legitimate placement of healing practices, medicinal substances, and medical technologies within Korea’s separate “Western Medicine” and “Korean Medicine” systems of health care and pharmaceutical distribution. The controversy concerned an attempt to use hi-tech imaging technology—the epitome of (...) modern medicine—in a clinic that maintains a strong ideological attachment to Korean healing traditions. A close study of this dispute, based on interviews, participant observation, and documentary analysis, showed that discursive positions taken about the translatability of medical technologies changed with the context of dispute, and did not reflect a stable epistemic boundary between rival medical paradigms. (shrink)

Mathematical models of tumour invasion appear as interesting tools for connecting the information extracted from medical imaging techniques and the large amount of data collected at the cellular and molecular levels. Most of the recent studies have used stochastic models of cell translocation for the comparison of computer simulations with histological solid tumour sections in order to discriminate and characterise expansive growth and active cell movements during host tissue invasion. This paper describes how a deterministic approach based on reaction-diffusion models (...) and their generalisation in the mechano-chemical framework developed in the study of biological morphogenesis can be an alternative for analysing tumour morphological patterns. We support these considerations by reviewing two studies. In the first example, successful comparison of simulated brain tumour growth with a time sequence of computerised tomography (CT) scans leads to a quantification of the clinical parameters describing the invasion process and the therapy. The second example considers minimal hypotheses relating cell motility and cell traction forces. Using this model, we can simulate the bifurcation from an homogeneous distribution of cells at the tumour surface toward a nonhomogeneous density pattern which could characterise a pre-invasive stage at the tumour-host tissue interface. (shrink)

The neural substrates of context effects in word perception are still largely unclear. Interhemispheric priming phenomena in word recognition, typically observed in normal subjects, are absent in commissurotomized patients. This suggests that callosal fibers may provide contextual integration. In addition, certain characteristics of human frontal cortical fields subserving sensorimotor learning, as investigated by positron emission tomography, provide evidence for contextual integration not confined to the visual system. This supports the notion of common aspects of cortical computations in different cerebral (...) areas. (shrink)

For more than a century the paradigm inspiringcognitive neuroscience has been modular and localist.Contemporary research in functional brain imaginggenerally relies on methods favorable to localizingparticular functions in one or more specific brainregions. Meanwhile, connectionist cognitive scientistshave celebrated the computational powers ofdistributed processing, and pioneered methods forinterpreting distributed representations. This papertakes a connectionist approach to functionalneuroimaging. A tabulation of 35 PET (positronemission tomography) experiments strongly indicatesdistributed function for at least the ''medium sized''anatomical units, the cortical Brodmann areas. Moreimportant, when these (...) PET experiments were interpretedas distributed representations, multidimensionalscaling revealed a ''brain activation space'' with asalient structure organized primarily by the sensorymodality of the stimulus, and secondarily by the typeof motor response. These results suggest that currentanalytical techniques in functional neuroimagingshould be augmented by distributed processinganalyses, and that these analyses may lead to manydiscoveries about the structure of ''inner space.''. (shrink)

One recursively enumerable real α dominates another one β if there are nondecreasing recursive sequences of rational numbers (a[n] : n ∈ ω) approximating α and (b[n] : n ∈ ω) approximating β and a positive constant C such that for all n, C(α − a[n]) ≥ (β − b[n]). See [R. M. Solovay, Draft of a Paper (or Series of Papers) on Chaitin’s Work, manuscript, IBM Thomas J. Watson Research Center, Yorktown Heights, NY, 1974, p. 215] and [G. J. (...) Chaitin, IBM J. Res. Develop., 21 (1977), pp. 350–359]. We show that every recursively enumerable random real dominates all other recursively enumerable reals. We conclude that the recursively enumerable random reals are exactly the Ω-numbers [G. J. Chaitin, IBM J. Res. Develop., 21 (1977), pp. 350–359]. Second, we show that the sets in a universal Martin-Lof test for randomness have random measure, and every recursively enumerable random number is the sum of the measures represented in a universal Martin-Lof test. (shrink)

This book constitutes the strictly refereed post-workshop proceedings of the 11th International Workshop on Computer Science Logic, CSL '97, held as the 1997 Annual Conference of the European Association on Computer Science Logic, EACSL, in Aarhus, Denmark, in August 1997. The volume presents 26 revised full papers selected after two rounds of refereeing from initially 92 submissions; also included are four invited papers. The book addresses all current aspects of computer science logics and its applications and thus presents the state (...) of the art in the area. (shrink)

Hydranencephaly is a developmental malady, where the cerebral hemispheres of the brain are reduced partly or entirely too membranous sacs filled with cerebrospinal fluid. Infants with this malady are presumed to have reduced life expectancy with a survival of weeks to few years and which solely depends on care and fostering of these individuals. During their life span these individuals demonstrate behaviours that are termed “vegetative” by neuroscientists but can be comparable to the state of being “aware” or “conscious”. Based (...) on the most simplified definition for consciousness i.e. “awareness” or “to be aware”, these individuals are undeniably aware of their existence and therefore should be termed “conscious”. The bigoted approach of neuroscience towards understanding consciousness is usually linked with the cortex of the brain and therefore a malady as hydranencephaly poses a great challenge to this field. This paper is a compilation of behaviours and aptitudes observed in several cases of hydranencephaly which suggests, that consciousness is not just a brain process, but is a highly quantum computed process that follows laws of quantum physics, giving rise to the subjective experience of consciousness in these individuals. (shrink)

Since Horn (1972) the notion of conversational implicature proposed by Grice has been put to use to explain certain interpretive differences between expressions in natural language and their counterparts in formal logic. For example, the sentences in (1) seem to convey more than they would be expected to if the natural language disjunction or had the same meaning as the logical disjunction ∨, or if the quantificational determiner some was interpreted as the existential quantifier ∃.

This volume is a guide to two types of transcendence of academic borders which seem necessary for understanding and modelling brain function.

; Some students in the audience liked the talk, but not all. The intuitive meaning of the sentences in (1) imposes restrictions (the material underlined in the glosses) that go beyond the meaning of logical disjunction or existential quantification: in formal logic, P ∨ Q is true if both disjuncts are, and ∃xP (x) is true if the P holds of all entities in the domain of quantification.

Since its conception nearly 20 years ago, Logic Programming - the idea of using logic as a programming language - has been developed to the point where it now plays an important role in areas such as database theory, artificial intelligence and software engineering. However, there are still many challenging research issues to be addressed and the UK branch of the Association for Logic Programming was set up to provide a forum where the flourishing research community could discuss important issues (...) of Logic Programming which were often by-passed at the large international conferences. This volume contains the twelve papers which were presented at the ALPUK's 3rd conference which was held in Edinburgh, 10-12 April 1991. The aim of the conference was to give a broad but detailed technical insight into the work currently being done in this field, both in the UK and by researchers as far afield as Canada and Bulgaria. The breadth of interest in this area of Computer Science is reflected in the range of the papers which cover - amongst other areas - massively parallel implementation, constraint logic programming, circuit modelling, algebraic proof of program properties, deductive databases, specialised editors and standardisation. The resulting volume gives a good overview of the current progress being made in the field and will be of interest to researchers and students of any aspects of logic programming, parallel computing or database techniques and management. (shrink)

Preface : consciousness redux -- What is consciousness? -- Who is conscious? -- Animal consciousness -- Consciousness and the rest -- Consciousness and the brain -- Tracking the footprints of consciousness -- Why we need a theory of consciousness -- Of wholes -- Tools to measure consciousness -- The uber-mind and pure consciousness -- Does consciousness have a function? -- Computationalism and experience -- Computers can't simulate experience -- Consciousness : here, there but not everywhere -- Coda : why this (...) matters -- References -- Notes. (shrink)

Lexical ambiguity is pervasive in language, and the nature of the representations of an ambiguous word's multiple meanings is yet to be fully understood. With a special focus on Chinese characters, the present study first established that native speaker's perception about a character's number of meanings was heavily influenced by the availability of its distinct word formations, while whether these meanings would be perceived to be closely related was driven by further conceptual analysis. These notions were operationalized as two (...) class='Hi'>computed metrics, which assessed the degree of dispersion across individual word formations and the degree of propinquity across clusters of word formations, respectively, in a distributional semantic space. The observed correlations between the computed and the perceived metrics indicated that the utility of word formations to tap into meaning representations of Chinese characters was indeed cognitively plausible. The results have demonstrated the extent to which distributional semantics could inform about meaning representations of Chinese characters, which has theoretical implications for the representation of ambiguous words more generally. (shrink)