6,413 research outputs found
Cardiac output in idiopathic normal pressure hydrocephalus: association with arterial blood pressure and intracranial pressure wave amplitudes and outcome of shunt surgery
No full textAbstract Background In patients with idiopathic normal pressure hydrocephalus (iNPH) responding to shunt surgery, we have consistently found elevated intracranial pressure (ICP) wave amplitudes during diagnostic ICP monitoring prior to surgery. It remains unknown why ICP wave amplitudes are increased in these patients. Since iNPH is accompanied by a high incidence of vascular co-morbidity, a possible explanation is that there is reduced vascular compliance accompanied by elevated arterial blood pressure (ABP) wave amplitudes and even altered cardiac output (CO). To investigate this possibility, the present study was undertaken to continuously monitor CO to determine if it is correlated to ABP and ICP wave amplitudes and the outcome of shunting in iNPH patients. It was specifically addressed whether the increased ICP wave amplitudes seen in iNPH shunt responders were accompanied by elevated CO and/or ABP wave amplitude levels. Methods Prospective iNPH patients (29) were clinically graded using an NPH grading scale. Continuous overnight minimally-invasive monitoring of CO and ABP was done simultaneously with ICP monitoring; the CO, ABP, and ICP parameters were parsed into 6-second time windows. Patients were assessed for shunt surgery on clinical grade, Evan's index, and ICP wave amplitude. Follow-up clinical grading was performed 12 months after surgery. Results ICP wave amplitudes but not CO or ABP wave amplitude, showed good correlation with the response to shunt treatment. The patients with high ICP wave amplitude did not have accompanying high levels of CO or ABP wave amplitude. Correlation analysis between CO and ICP wave amplitudes in individual patients showed different profiles [significantly positive in 10 (35%) and significantly negative in 16 (55%) of 29 recordings]. This depended on whether there was also a correlation between ABP and ICP wave amplitudes and on the average level of ICP wave amplitude. Conclusions These results gave no evidence that the increased levels of ICP wave amplitudes seen in iNPH shunt responders prior to surgery were accompanied by elevated levels of ABP wave amplitudes or elevated CO. In the individual patients the correlation between CO and ICP wave amplitude was partly related to an association between ABP and ICP wave amplitudes which can be indicative of the state of cerebrovascular pressure regulation, and partly related to the ICP wave amplitude which can be indicative of the intracranial compliance.</p
K Wizdom Pte Ltd (Optimate)
No full textIn the current industry, there exist many marketing platforms that provide digital marketing
services to the clients. The services range from Video Campaigns, to Pay-Per-Click and to
Search Advertisements. The platforms which are already in the market target multiple kinds of
audience, ranging from small businesses to multinational companies. This report emphasizes and
elaborates on what the author has learnt and done during the entire Final Year Project with K
Wizdom Pte Ltd (Optimate). Chapter One will showcase introduction, give the nature of the
projects assigned, and also background information about K Wizdom Pte Ltd (Optimate).
Chapter Two and Chapter Three will provide a detailed description of the projects which were
allocated to the author. Chapter Four of this report is the summary to give an overview of what
the author has learnt and what was accomplished during the author’s Final Year Project. Finally,
Chapter Five and Chapter Six of this report document the key learning and the references to the
materials that the author has used.Bachelor of Engineering (Computer Science
Comparison of several author indices for gauging academic productivity
No full textBackground
Many author indices exist to gauge academic productivity. Several of these indices are calculated based upon an author's scholarly publication record, but the measurement methodology to calculate each index varies considerably, and the precise function being used, as well as the end result, is often complex and difficult to assess.
Method
Two straightforward methods to weigh author productivity from the publication and citation record were evaluated as possible means for providing a clearer assessment of scholarly activity. The author characteristic index (termed c-index) assigns author rank for each publication based upon author position. The characteristic prime (c') -index normalizes author rank from author position, so that the total weight per publication is unity. The top 10 scholars with keyword 'celiac disease' in the Google Scholar database were then assessed using these metrics. Rankings according to total number of publications, h-index, and c- and c'-indices were compared, then tabulated along with total papers included for assessment, and mean values per paper for author position, number of authors, citations, and year of publication.
Results
The order of the top ten authors with keyword 'celiac disease' varied substantially depending upon whether the h-index, c-index, or c'-index was used as a gauge. The characteristic indices assign credit to authors according to their position in an author list. The affiliated metrics provided a more complete picture of scholarly activity.
Conclusions
Academic achievement by scholars, based upon quantitative publication characteristics, has recently become of interest for evaluating job candidates, for determining work performance, and for bestowing awards and honors. The characteristic indices as described herein are readily calculated and interpreted, and may improve the assessment of scholarly activity
The baseline pressure of intracranial pressure (ICP) sensors can be altered by electrostatic discharges
No full textAbstract Background The monitoring of intracranial pressure (ICP) has a crucial role in the surveillance of patients with brain injury. During long-term monitoring of ICP, we have seen spontaneous shifts in baseline pressure (ICP sensor zero point), which are of technical and not physiological origin. The aim of the present study was to explore whether or not baseline pressures of ICP sensors can be affected by electrostatics discharges (ESD's), when ESD's are delivered at clinically relevant magnitudes. Methods We performed bench-testing of a set of commercial ICP sensors. In our experimental setup, the ICP sensor was placed in a container with 0.9% NaCl solution. A test person was charged 0.5 - 10 kV, and then delivered ESD's to the sensor by touching a metal rod that was located in the container. The continuous pressure signals were recorded continuously before/after the ESD's, and the pressure readings were stored digitally using a computerized system Results A total of 57 sensors were tested, including 25 Codman ICP sensors and 32 Raumedic sensors. When charging the test person in the range 0.5-10 kV, typically ESD's in the range 0.5 - 5 kV peak pulse were delivered to the ICP sensor. Alterations in baseline pressure ≥ 2 mmHg was seen in 24 of 25 (96%) Codman sensors and in 17 of 32 (53%) Raumedic sensors. Lasting changes in baseline pressure > 10 mmHg that in the clinical setting would affect patient management, were seen frequently for both sensor types. The changes in baseline pressure were either characterized by sudden shifts or gradual drifts in baseline pressure. Conclusions The baseline pressures of commercial solid ICP sensors can be altered by ESD's at discharge magnitudes that are clinically relevant. Shifts in baseline pressure change the ICP levels visualised to the physician on the monitor screen, and thereby reveal wrong ICP values, which likely represent a severe risk to the patient.</p
Cerebrospinal fluid pulse pressure amplitude during lumbar infusion in idiopathic normal pressure hydrocephalus can predict response to shunting
No full textAbstract Background We have previously seen that idiopathic normal pressure hydrocephalus (iNPH) patients having elevated intracranial pressure (ICP) pulse amplitude consistently respond to shunt surgery. In this study we explored how the cerebrospinal fluid pressure (CSFP) pulse amplitude determined during lumbar infusion testing, correlates with ICP pulse amplitude determined during over-night ICP monitoring and with response to shunt surgery. Our goal was to establish a more reliable screening procedure for selecting iNPH patients for shunt surgery using lumbar intrathecal infusion. Methods The study population consisted of all iNPH patients undergoing both diagnostic lumbar infusion testing and continuous over-night ICP monitoring during the period 2002-2007. The severity of iNPH was assessed using our NPH grading scale before surgery and 12 months after shunting. The CSFP pulse was characterized from the amplitude of single pressure waves. Results Totally 62 iNPH patients were included, 45 of them underwent shunt surgery, in whom 78% were shunt responders. Among the 45 shunted patients, resistance to CSF outflow (Rout) was elevated (≥ 12 mmHg/ml/min) in 44. The ICP pulse amplitude recorded over-night was elevated (i.e. mean ICP wave amplitude ≥ 4 mmHg) in 68% of patients; 92% of these were shunt responders. In those with elevated overnight ICP pulse amplitude, we found also elevated CSFP pulse amplitude recorded during lumbar infusion testing, both during the opening phase following lumbar puncture and during a standardized period of lumbar infusion (15 ml Ringer over 10 min). The clinical response to shunting after 1 year strongly associated with the over-night ICP pulse amplitude, and also with the pulsatile CSFP during the period of lumbar infusion. Elevated CSFP pulse amplitude during lumbar infusion thus predicted shunt response with sensitivity of 88 and specificity of 60 (positive and negative predictive values of 89 and 60, respectively). Conclusions In iNPH patients, shunt response can be anticipated in 9/10 patients with elevated overnight ICP pulse amplitude, while in only 1/10 with low ICP pulse amplitude. Additionally, the CSFP pulse amplitude during lumbar infusion testing was elevated in patients with elevated over-night ICP pulse amplitude. In particular, measurement of CSFP pulse amplitude during a standardized infusion of 15 ml Ringer over 10 min was useful in predicting response to shunt surgery and can be used as a screening procedure for selection of iNPH patients for shunting.</p
Increased prevalence of cardiovascular disease in idiopathic normal pressure hydrocephalus patients compared to a population-based cohort from the HUNT3 survey
No full textBackground
Idiopathic normal pressure hydrocephalus (iNPH) is one of few types of dementia that can be treated with shunt surgery and cerebrospinal fluid (CSF) diversion. It is frequently present with cerebral vasculopathy; however, how the prevalence of cardiovascular disease compares between iNPH patients and the general population has not yet been established. Therefore, a case–control study was performed to examine whether the prevalence of cardiovascular disease (arterial hypertension, angina pectoris, cardiac infarction, and diabetes) was different in 440 iNPH patients, when compared to 43,387 participants of the Nord-Trøndelag Health 3 Survey (The HUNT3 Survey), which was considered as the general control population.
Findings
In iNPH patients aged 35–70 years, we found increased prevalence for arterial hypertension (males), angina pectoris (females and males), and cardiac infarction (males), as compared with the HUNT3 control group with significant odds ratio estimates. In addition, the prevalence of diabetes was increased in both age groups 35–70 years (males) and 70–90 years (females and males).
Conclusions
The data show significantly increased prevalence of cardiovascular disease iNPH patients, which provide evidence that cardiovascular disease is involved as an exposure in the development of iNPH
Copyright, contratto e accesso alla conoscenza: un’analisi comparata = Copyright, contract and access to knowledge: a comparative analysis.
No full textIl processo di digitalizzazione e lo sviluppo dei media, stravolgendo il paradigma tradizionale del copyright/diritto d’autore conducono a reazioni opposte. Da un lato, estendendo in vario modo l’ampiezza dell’esclusiva autorale favoriscono l’adozione di regole restrittive di accesso e uso dei contenuti; dall’altro, alimentano le logiche di condivisione, specie in alcune aree di produzione del sapere.
Il contratto, pur mutata la propria natura nella dimensione digitale, rappresenta la prima leva per l’affermazione di tali divergenti dinamiche, che, in entrambe le direzioni, riguardano anche la circolazione della conoscenza scientifica. Nel senso dell’apertura, lo strumento negoziale consente di perseguire i principi affermati dal movimento dell’Open Access (OA), abbattendo le barriere economiche e giuridiche all’accesso e utilizzo dei contenuti.
Dal deposito e pubblicazione su archivi istituzionali e disciplinari di opere transitate già attraverso i canali editoriali convenzionali, comunemente definita green road, alla pubblicazione su riviste ad accesso aperto, gold road, il fenomeno si sviluppa dal basso verso l’alto grazie alle dichiarazioni di principio e alle norme informali che hanno sin ora guidato le comunità accademiche nell’affermazione dell’OA. Di recente, tuttavia, i principi dell’OA sono oggetto di attenzione da parte del decisore pubblico che, pur timidamente, ne “impone” l’attuazione a tutte le comunità accademiche. Eppure, il diritto formale non sembra da solo sufficiente: è soltanto il primo tassello di una disciplina organica tesa a definire regole e incentivi per la produzione e la disseminazione della conoscenza scientifica, allo scopo di bilanciare la libertà “accademica” con il diritto di accesso alla conoscenza. = ENGLISH VERSION = Along with a comparative perspective that takes account of the U.S. and Italian law, this work aims to explore the interface between copyright and contract lae in publishing process.
In the current publishing environment, contracts and technology play a dominant role in the exploitation of copyrighted works. Publishers are granted by assignment of all copyright rights to reproduce and publish the work, but also to exercise control over its contents through technological protection measures. At the same time, mass digitization allows libraries and other organizations to make contents available online, which it entails a redefinition of the traditional publishing process and introduces new players to the scene (e.g., Google Books).
Hence, technology proves to be a powerful instrument for the spread of knowledge and it is on this pattern that Open Access (OA) is rapidly gaining ground.
Mostly based on a bottom-up approach that is on soft law, institutional policies and contracts, OA designs a new legal environment targeting the objectives of free accessibility, further distribution, and proper archiving of publications. These aims can be achieved through the creation of new open access business models to publish on OA journals (gold road) or to self-archive in institutional or disciplinary repositories works that have been originally published in conventional journals (green road).
However, in order for OA to be fully developed it is necessary to devise a principled and feasible approach to the dissemination of scholarly works against the current social, economic and legal background.
Indeed, the importance of OA is steadily recognized by legislators who integrate OA provisions into their legal system. This is an innovation of great significance, which was first fostered in the USA, and then extended in some European countries such as Italy and Germany in the European framework. Nevertheless, considering the different law systems, the formal law need to be combined with national strategies and institutional policies providing adequate incentives to the authors, while also promoting academic freedom and the right to knowledge access
The shannon capacity on C(n,k)
No full textThis thesis focuses on a problem formulated by Claude Shannon named the Shannon capacity. This problem is about information rate per time unit over a noisy channel. The noisy channel is here represented by a graph. We specifically focus on a class of circulant graphs that are denoted by C(n,k) with vertex set z/nz, where all vertices are connected with the k-1 vertices before and after it. We will discuss upper bounds that were found for the Shannon capacity and how C(n,k) behaves with these upper bounds. After that we will focus on multiple ways to calculate lower bounds for the Shannon capacity of . For these three search methods will be used. These are exhaustive searching for optimal values, optimal ways to make packagings and solutions created by using a special form. As last the answers will be discussed by combining the upper and lower bounds for C(n,k). From this conclusions are drawn after which some possibilities will be given for further research. Applied Mathematic
Pharmacogenetics of ophthalmic topical β-blockers
No full textGlaucoma is the second leading cause of blindness worldwide. The primary glaucoma risk factor is elevated intraocular pressure. Topical β-blockers are affordable and widely used to lower intraocular pressure. Genetic variability has been postulated to contribute to interpersonal differences in efficacy and safety of topical β-blockers. This review summarizes clinically significant polymorphisms that have been identified in the β-adrenergic receptors (ADRB1, ADRB2 and ADRB3). The implications of polymorphisms in CYP2D6 are also discussed. Although the candidate-gene approach has facilitated significant progress in our understanding of the genetic basis of glaucoma treatment response, most drug responses involve a large number of genes, each containing multiple polymorphisms. Genome-wide association studies may yield a more comprehensive set of polymorphisms associated with glaucoma outcomes. An understanding of the genetic mechanisms associated with variability in individual responses to topical β-blockers may advance individualized treatment at a lower cost
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