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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Valutazione quantitativa di task motori in pazienti con malattia di Parkinson pre e post trattamento farmacologico
No full textLAUREA MAGISTRALELa valutazione delle funzionalità motorie in pazienti affetti da disturbi del movimento richiede al clinico di osservare l’esecuzione di task motori specifici al fine di determinare sia lo stato di disabilità globale del paziente, sia l’efficacia di trattamenti farmacologici, chirurgici e riabilitativi. Per effettuare tale analisi nel corso degli anni sono state quindi elaborate numerose scale cliniche dedicate alla valutazione delle diverse patologie sotto differenti aspetti (stadiazione della patologia, grado di disabilità motoria e cognitiva), al fine di fornire, a chi esegue la valutazione, un valido strumento di supporto per l’assegnazione di un punteggio in relazione alle performance motorie eseguite dai pazienti. Tuttavia, la valutazione funzionale basata unicamente sull’utilizzo di una scala clinica non garantisce appieno i requisiti di oggettività e ripetibilità richiesti da un metodo di analisi clinica con finalità relative alla gestione sanitaria assistenziale del paziente. Infatti la valutazione eseguita mediante la sola osservazione dei task motori da parte del clinico risulta affetta da una forte componente di soggettività, legata inevitabilmente ai limiti delle sue percezioni sensoriali. La valutazione così ottenuta si rivela quindi caratterizzata da fenomeni di variabilità sia intra che inter-soggettiva che aumentano notevolmente l’incertezza dell’esito clinico. Inoltre l’attività clinica giornaliera delle strutture che si occupano di effettuare queste valutazioni non consente ai clinici di osservare sul paziente fenomeni legati alla variabilità temporale dell’efficacia del trattamento proposto sul paziente, in quanto richiederebbe analisi ripetute ad intervalli di tempo troppo estesi.
Questo lavoro di tesi nasce dall’esigenza di definire un metodo di valutazione quantitativa delle facoltà motorie dei pazienti affetti da Malattia di Parkinson che consenta di monitorare la variabilità giornaliera dell’efficacia del trattamento farmacologico somministratogli. La Malattia di Parkinson è una patologia neurodegenerativa del sistema nervoso centrale legata ad una degenerazione dei neuroni dopaminergici della sostanza nera che porta ad una rapida scomparsa di queste strutture, causando l’insorgenza di sintomatologie motorie e non motorie che sono causa di una progressiva disabilità del paziente. I sintomi motori caratteristici di questa patologia risultano essere bradicinesia, rigidità degli arti e del tronco e tremore (triade sintomatologica del Parkinson), a cui si associano instabilità posturale e disturbi della deambulazione, mentre nella sintomatologia non motoria si annoverano costipazione intestinale e della vescica, ipertensione ortostatica e l’insorgenza di stati psicologici come la depressione. La Malattia di Parkinson è contemplata come disturbo del movimento, in quanto la sintomatologia motoria risulta essere la causa principale della disabilità che il paziente incontra nelle prime fasi della patologia, mentre i sintomi non motori tendono ad essere maggiormente determinanti nelle fasi più avanzate. Non disponendo di una terapia risolutiva in grado di ostacolare il processo degenerativo patologico, si ricorre unicamente ad un’azione di contrasto della sintomatologia. Il trattamento farmacologico più diffuso è la somministrazione di levodopa, farmaco in grado di sopperire alla carenza di dopamina a livello centrale e quindi di contrastare i sintomi motori dopaminergici. Questo trattamento comporta l’insorgenza di fluttuazioni motorie giornalieri dovute alla sua ridotta emivita e di ulteriori fluttuazioni sul lungo periodo, dovute al progredire della degenerazione a livello centrale, che richiedono un continuo aumento del dosaggio. È di fondamentale importanza di conseguenza operare un’accurata valutazione periodica della sintomatologia di questi pazienti, al fine di garantirne una corretta gestione clinica e terapeutica. Nel processo di valutazione trovano utilizzo diverse scale cliniche finalizzate all’analisi motoria e cognitiva dei pazienti: tra queste la scala clinica MDS-UPDRS risulta avere un ruolo predominante come principale strumento di supporto alla valutazione. Al suo interno è possibile riscontrare una sezione interamente dedicata all’analisi motoria mediante l’esecuzione di specifici task motori concepiti per caratterizzare la disabilità motoria del paziente. Ogni task viene valutato dal clinico secondo un punteggio da 0 a 4 crescente in maniera proporzionale alla gravità delle condizioni riscontrate.
Nel corso dello studio descritto all’interno di questo lavoro sono state analizzate le principali tecniche di valutazione quantitativa delle funzionalità motorie dei soggetti affetti da Malattia di Parkinson proposte in letteratura, basati su misure dei movimenti effettuate mediante sistemi opto-elettronici, dispositivi indossabili (costituiti da accelerometri triassiali, sensori inerziali e sensori di forza) e dispositivi mobile. Questi ultimi in particolare hanno di dimostrato di possedere un grande potenziale per consentire la valutazione motoria domiciliare del paziente, riuscendo di conseguenza a fornire al medico ulteriori informazioni sulle fluttuazioni motorie causate dal trattamento farmacologico.
Successivamente è stato ci si è prefissato l’obiettivo di definire un metodo di valutazione quantitativo, basato sull’analisi di quattro task motori della scala MDS-UPDRS (agilità gambe, movimenti rapidi delle mani, movimenti rapidi delle dita delle mani e prono-supinazione delle mani) scelti in modo tale da poter osservare i principali effetti della levodopa sulla sintomatologia motoria (sono stati infatti scartati i task motori relativi a sintomatologie come instabilità posturale e tremore, in quanto poco responsivi al trattamento farmacologico). I task motori presentano una forte analogia, in quanto sono caratterizzati da movimenti ripetuti che si chiede di eseguire alla maggiore ampiezza e velocità possibile. La valutazione del task deve basarsi sull’entità di tali ampiezze e velocità e sulla capacità del soggetto di mantenere costante l’ampiezza e regolare il ritmo.
Sono stati quindi selezionati sedici pazienti affetti da forma idiopatica della Malattia di Parkinson a cui è stato chiesto di eseguire i task motori selezionati per l’indagine, sia precedentemente all’assunzione della levodopa (fase OFF), sia successivamente alla sua somministrazione (fase ON). Il metodo di valutazione quantitativa è stato infatti testato per quantificare l’efficacia della levodopa sui task motori. Ogni movimento è stato acquisito mediante sistema opto-elettronico e successivamente elaborato mediante appositi protocolli di analisi cinematica. Ogni task motorio è stato caratterizzato da due successioni di valori:
Ampiezza: intesa come la successione delle differenze fra valore massimo e valore minimo di ogni ripetizione del movimento eseguito;
Frequenza: intesa come la successione degli inversi degli intervalli di tempo che intercorrono fra un massimo dell’ampiezza e successivo.
Per garantire un approccio multidimensionale all’analisi dei diversi movimenti, per ogni successione è stato calcolato il relativo coefficiente di variazione, ovvero il rapporto fra la deviazione standard e la media campionaria della successione. In questo modo il coefficiente di variazione dell’ampiezza assume un valore adimensionale tanto maggiore quanto più il movimento risulta di ampiezza ridotta e irregolare e il coefficiente di variazione della frequenza assume un valore adimensionale tanto più elevato quanto più la velocità è ridotta e di ritmo irregolare.
L’analisi multidimensionale è stata operata mediante un metodo grafico, rappresentando, per ogni task, sull’asse delle ascisse il coefficiente di variazione delle ampiezze e in ordinata il coefficiente di variazione delle frequenze. In questo modo ogni performance motoria viene rappresentata da un punto sul piano definito dai due coefficienti che, presentando un andamento analogo in relazione alle condizioni motorie del paziente, fanno sì che tale punto si trovi ad una distanza tanto maggiore dall’origine degli assi tanto più il movimento è di ampiezza e velocità ridotta e con ritmo e ampiezze irregolari, corrispondente ad un livello di disabilità motoria più elevato. È stato di conseguenza scelto come indicatore della disabilità motoria relativa ad ogni task, la distanza motoria del punto definito dai coefficienti dall’origine degli assi, ricavando poi dalla loro somma un indicatore delle condizioni globali del paziente.
I risultati ottenuti dalla valutazione dei task motori di ogni paziente hanno dimostrato la validità del metodo proposto, riscontrando infatti una correlazione di circa il 56% con il punteggio clinico MDS-UPDRS, evidenziando però come l’approccio quantitativo consenta di cogliere dinamiche del movimento non percepite durante l’esame clinico tradizionale perché mascherate dalla variazione predominante di uno degli aspetti cinematici. Inoltre è stato possibile analizzare l’azione del farmaco sui singoli parametri cinematici, osservando un’entità media dell’efficacia confrontabile su ampiezza e frequenza dei movimenti, riscontrando però una maggior occorrenza dei miglioramenti in velocità di esecuzione. I risultati hanno anche evidenziato una diversa azione del farmaco fra lato sinistro e lato destro, in particolar modo sui task motori degli arti superiori, evidenziando maggiori benefici riscontrati sul lato destro, e di conseguenza oggetto di studi futuri per comprendere al meglio le dinamiche di risposte al trattamentoThe evaluation of the motor functions of patients affected by movement disorders requires the observation of specifically motor tasks, in order to define the effectiveness of pharmacological, surgical and rehabilitative treatments. During the years, the research has provided several clinical scales in order to enable physicians to evaluate different aspects of the pathological states (staging the disease, motor and cognitive disability) by assigning a numerical score to the performance of patients. However, the only use of a clinical scale does not meet requirements of objectivity and repeatability needed to consent the correct clinical management of the patient because of subjectivity caused by the limited perception of the physician. The evaluation performed by clinical scales introduces high variability of the scores obtained in different analysis, causing the loss of reliability of the clinical results found. Furthermore, the functional evaluation performed only within follow-up session makes impossible for the physicist to observe the daily variation of the effectiveness of the pharmacological treatment.
The motivation of this work is found in the need to provide a quantitative method for the motor evaluation of patients with Parkinson’s Disease, capable of monitoring the daily effectiveness of the pharmacological therapy. Parkinson Disease is a neurodegenerative pathology of the central nervous system characterized by a loss of dopaminergic neurons causing a progressive disability connected to motor and not-motor symptoms. The main motor issues that characterize the Parkinson’s Disease are bradykinesia, tremor and arm and trunk rigidity, which cause postural instability and deambulation problems. The not-motor symptomatology, that becomes prevailing in the advanced phase of the disease, is characterized by bowel and bladder constipation, orthostatic hypertension and rising of persistent psychological states like depression. The Parkinson’s Disease is considered a movement disorder because motor symptoms are the first cause of disability met by patients in the early stages of the disease.
Currently there is not pharmacological or surgical solution to arrest the degeneration of dopaminergic neurons, so the only therapeutic solution available is to contrast symptoms. Levodopa is the most diffused pharmacological treatment for Parkinson’s Disease that consents to oppose at the loss of dopamine in the central nervous system and contrast dopaminergic motor symptoms. However, the weak of half-life of Levodopa causes the rise of motor fluctuations during the day (alternate of phase ON and phase OFF), whereas the progressive degeneration of the neural structures causes long-term motor fluctuations, connected to the worsening of the neural conditions, that requires a continuous increase of the dose of Levodopa. Then, it is very important to perform an accurate evaluation of the effectiveness variability during the treatment to consent a correct management of patients. Several clinical scales are used to provide this evaluation, in particular the MDS-UPDRS, the most diffused support devices to analyse the effectiveness of therapeutic treatments, which contains a part dedicated to motor evaluation. It is composed by motor task performed by patients in which the physician assigns a score between 0 and 4 proportionally to the severity of motor conditions.
The main evaluation techniques of motor functions in Parkinson’s Disease, based on opt-electronic systems, wearable devices (consist of accelerometers, inertial and forces sensor) and mobile devices, were analysed in literature. Mobile devices like smartphones in particular show a big potential to define evaluation methods based on measures taken at patient home, giving physicians information about daily motor fluctuations caused by the treatment.
The purpose of the study was to define quantitative method based on analysis of four MDS-UPDRS tasks, selected to observe main effects of levodopa on motor symptoms. Every motor task presents similarities with others; in fact, everyone requires the execution of a periodic movement at maximum speed and amplitude. The evaluation of the movements is based on the entities of amplitude and speed and the ability of the patient to maintain them regular.
Sixteen subjects affected by Parkinson’s Disease and medicated with levodopa were recruited for this study. Every patient was asked to perform every motor task chosen for the evaluation (leg agility, hand movements, finger tapping and prono-supination movements of hands) prior to assume the levodopa (phase OFF) and after the assumption (phase ON). Every movement was acquired by an opto-electronic system and subsequently processed in order to analyse its kinematic. Each motor task was characterized by two successions:
Amplitude: succession of the difference between maximum and minimum value of the each movement amplitude;
Frequency: succession of the inverse of the time interval between a maximum of the amplitude and the following one;
A multi-dimensional approach was chosen to realize the evaluation: for each succession, the relative variation coefficient was calculated. This coefficient is defined as the ratio between the standard deviation and the average value of each succession. Therefore, the variation coefficient of amplitude assumes a higher value as the movement amplitude results limited and not regular, while the variation coefficient of the frequency assumes higher values as the movement frequency results limited with an irregular rhythm.
The multi-dimensional analysis was realized with a graphic method, representing on the axes the variation coefficient of the amplitude and the variation coefficient of the frequency for each task. So, the performed movement was represented by a point which is farther from the origin as the execution reveals limited and irregular amplitude and speed. The Euclidean distance between the point and the origin consequently represents the motor impairment of the patient during the performance and it was chosen as a quantitative indicator of the disability. The sum of every Euclidean distance was selected as a global indicator of motor disability of each patient.
The results given by this work demonstrated the validity of the proposed method, characterized by a middle-high correlation with the scores obtained by the clinical scale MDS-UPDRS (56%). The method evdences also the ability to detect kinematic aspects not recognizable using an observational approach, because of the masking caused by prevailing variation on the movement kinematic. The multi-dimensional approach has made possible to analyse the action of levodopa on each kinematic aspect of the movement: the effectiveness on frequency and amplitude presents comparable average entities, but the effectiveness on frequency occurs more often than the effectiveness on amplitude. Results also show a different action of levodopa between left and right side, with an average effectiveness higher on the right side, especially for upper limbs motor tasks, so the main reasons will be research in next studies
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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