1,721,450 research outputs found
Análisis descriptivo del proceso de desmonte y habilitación de tierras en el Chaco Argentina
Full text linkLa República Argentina, aún con las discontinuidades institucionales y altibajos de un país en vías de desarrollo, ha logrado crear y mantener estructuras institucionales reguladoras del patrimonio ambiental a todos los niveles de la administración pública (Morello y Rodríguez, 2007). Hacia fines del siglo xx, los eventos vinculados con el ambiente más relevante a nivel nacional y regional habían sido: a) la creación, entre 1950 y 1975 de grupos de trabajo en ambiente acuático y terrestre auspiciados y financiados por CONICET, INTA y las Univ. Nacionales; b) El creciente interés en el Gran Buenos Aires monitoreo de la contaminación aérea en áreas industriales (partidos Avellaneda, Lanús, Quilmes, La Matanza); c) la elaboración de propuestas de desarrollo sostenible en zonas áridas elaborados por grupos técnico-científicos del INTA y por lo menos 4 universidades: Bahía Blanca, La Pampa, Comahue y Cuyo; d) manejo de sobrepastoreo e incendios en ambiente serrano, Univ. de Córdoba, Univ. de Santiago del Estero; e) análisis de ambiente humano (Fundación Bariloche y desde 1972 la Secretaria de Ambiente y Desarrollo Sustentable (en adelante SAyDS); f) climatología ambiental (SMN, INTA, SAyDS, UBA); g) degradación de ambientes de bosques nativos (Univ. de Córdoba, UNLP, Univ. Misiones, Univ. Tucumán, Instituto Forestal Nacional); h) ambientes agroproductivos y agroecología (UNCO, UBA, Univ. de Cuyo y fundamentalmente INTA); i) ambiente urbano (UNNE, FADU-UBA, Univ. Rosario); j) ambiente de pastizales y arbustales (UBA, Univ. Río Cuarto, INTA, Univ. de Córdoba, Univ. de La Pampa, Univ. de Bahía Blanca); k) ambientes protegidos para conservación de la biodiversidad APN, INTA, SAyDS, Univ. de Cuyo, gobiernos provinciales en especial Santiago del Estero, San Juan y Chubut; l) ambientes de bosque nativo y plantaciones de exóticas (Univ. Comahue, APN); m) restauración de ambientes naturales y seminaturales (APN, UNLP, Univ. de Comahue, Univ. de Córdoba, Univ. Cuyo; Univ. de Tucumán); n) ordenamiento territorial y planificación ambiental, (UNNE, UBA, Univ. de Tucumán); o) estudio y control de procesos erosivos periurbanos y rurales (INTA, APN, UBA, Univ. de Bahía Blanca)...Fil: Morello, Jorge Helios. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria; Argentina. Universidad de Buenos Aires. Facultad de Arquitectura y Urbanismo. Grupo de Ecología del Paisaje y Medio Ambiente; ArgentinaFil: Rodriguez, Andrea Fernanda. Universidad de Buenos Aires. Facultad de Arquitectura y Urbanismo. Grupo de Ecología del Paisaje y Medio Ambiente; ArgentinaFil: Pengue, Walter Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria; Argentina. Universidad de Buenos Aires. Facultad de Arquitectura y Urbanismo. Grupo de Ecología del Paisaje y Medio Ambiente; Argentina. Universidad Nacional de General Sarmiento; Argentin
Adversidades climáticas en fruticultura
Full text linkLas condiciones climáticas son consideradas adversidades cuando producen daños sobre la calidad y cantidad de la producción. Las pérdidas ocasionadas pueden ser muy importantes.EEA Alto ValleFil: Rodriguez, Andrea Betiana. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Alto Valle; ArgentinaFil: Muñoz, Angel Rafael. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Alto Valle; Argentin
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
Event-related potentials and pathology in rodent models of Alzheimer's disease and Absence Epilepsy
No full textL'elettroencefalografia (EEG), ed in particolare lo studio dei potenziali e delle oscillazioni correlate ad eventi (ERPs e EROs, dall'inglese event-related potentials, event-related oscillations), costituisce uno strumento ampiamente utilizzato sia in clinica, sia nel campo della ricerca preclinica, dei disordini cerebrali, grazie anche a sui bassi costi e la non invasività. L'attività elettrica cerebrale dell'uomo e dei roditori sono accumunate da diverse caratteristiche; ciò ha reso tali tecniche di particolare interesse anche dal punto di vista traslazionale. In questa tesi di dottorato sono state effettuate registrazioni encefalografiche in topi “wild-type”, in modelli sperimentali di topi transgenici della malattia di Alzheimer, in modelli sperimentali di ratto della epilessia tipo assenza giovanile (absence epilepsy) e in topi spontaneamente affetti da epilessia legata al sonno.1) Lo studio dei potenziali correlati ad eventi sonori (AERPs, dall'inglese auditory event-related potentials) e delle EROs in risposta a diversi tipi di manipolazioni durante un paradigma oddball uditivo passivo in topi C56Bl/6 sani hanno costituito l’oggetto del primo studio presentato nella tesi. Le componenti evocate mostrano lo stesso ordine di polarità descritto in uomo e ratto ma con latenze più brevi, differenza probabilmente determinata dalle diverse dimensioni dell'encefalo. A differenza delle componenti precoci, la componente P3 è risultata sensibile alla probabilità di presentazione dello stimolo; in particolare è stata osservata una riduzione all'aumentare della probabilità di presentazione dello stimolo. Inoltre, le EROs associate alla componente P3 risultano essere simili a quelle umane in termini di evoked power e di phase-locking index (PLI). I dati sperimentali qui presentati indicano, quindi, che la componente P3 nel modello murino presenta caratteristiche simili alla componete P300 umana in termini di elaborazione dello stimolo.2) La seconda parte della tesi è focalizzato sullo studio dei topi TASTPM, un modello sperimentale di roditore della malattia di Alzheimer. In particolare, lo studio delle AERPs, delle EROs, e più in generale dell'EEG, hanno mostrato un incremento nella latenza della componente P3 e una riduzioni nell’ampiezza delle componenti N1, P2, e P3 durante l’elaborazione dello stimolo target. Inoltre, i dati neurofisiologici hanno mostrato un incremento dell’attività delta e theta pre-stimolo associato ad una scarsa sincronizzazione dopo lo stimolo target, indici di un deficit nella connettività tra le regioni frontale e parietali, e uno scarso aumento di potenza theta con lo stimolo target. Inoltre, sono state osservate alterazioni elettroencefalografiche a carico del sonno non-REM, quali l’aumento del potere di theta, alpha e beta. Questi risultati supportano l'ipotesi che nel modello sperimentale di topo transgenico TASTPM della malattia di Alzheimer, EEG, AERPs ed EROs potrebbe essere utilizzato come biomarker in quanto riflettono alterazioni dei circuiti neuronali tipici della malattia.3) Nel terzo studio sperimentale della tesi sono state studiate le interazioni tra la corteccia somatosensoriale e i diversi nuclei del talamo, che costituiscono il sistema cortico-talamo-corticale, nel modello di ratto WAG / Rij mediante potenziali evocati elettrici. I dati dello studio hanno mostrato che i nuclei talamici appartenenti alla rete somatosensoriale e alla rete limbica hanno patterns di risposte evocate intensità-dipendente. In particolare, sono state osservate risposte molto diverse tra la parte rostrale e caudale del nucleo reticolare del talamo. Tali risposte evocate riflettono la diversa interazione della corteccia somatosensoriale ipereccitabile con questi circuiti ed indicano, inoltre, che parte caudale e rostrale del nucleo talamico reticolare possono giocare ruoli diversi nel mantenimento delle scariche di onde durante il sonno.4) Nella quarta parte sperimentale della tesi è stata focalizzata sullo studio della struttura del sonno, e dei ritmi sonno-veglia, e sulla caratterizzazione delle scariche spike-waves (di tipo punta-onda) nel modello di topi AJ/JAX. Le nostre analisi indicano che questo ceppo murino presenta scariche spike-waves ed alterazioni nell'architettura sonno-veglia equivalenti a quelle riportate in pazienti con epilessia di tipo assenza e in modelli genetici di ratto. I risultati dello studio sottolineano, quindi, l'importanza dell’EEG come biomarcatore translazionale nei modelli preclinici.Nel loro complesso, i dati sperimentali qui presentati forniscono informazioni utili alla comprensione delle proprietà dei potenziali evocati nei modelli sperimentali di roditori e sostengono l’ipotesi per cui l'analisi dei segnali EEG posssa costituire uno strumento prezioso sia nello studio dei meccanismi di elaborazione neurosensoriale, sia come biomarker traslazionale nello studio di malattie neurologiche.Electroencephalography (EEG), including the study of event-related potentials (ERPs) and event-related oscillations (EROs), are cost-effective tools in both the clinical practice and in preclinical research field of brain disorders. The electrical activity in the human vs. the rodent’s brain share strong similarities, which make these techniques very attractive from a translational standpoint, but much still needs to be accomplished in order to fully characterize the EEG response as a viable biomarker.We carried out recording experiments in: 1) a wild-type mouse strain; 2) a transgenic mouse regarded as a model of Alzheimer’s disease; 3) a rat model of absence epilepsy; and 4) and inbred mouse spontaneously affected by sleep-related epilepsy. 1) In wild-type C56Bl/6 mice, we tested the sensitivity of auditory event-related potentials (AERPs) and EROs to different manipulations during a passive auditory oddball paradigm. The evoked components showed the same order of polarity described in human and rats, but with shorter latencies, possibly due to the differences in brain size. The P3 component, unlike the earlier components, was sensitive to the probability of stimulus presentation, i.e. it was reduced when the probability of stimulus presentation increased. Also, the EROs associated with the P3 component in mice exhibited similarities with human EROs in terms of evoked power and phase-locking index (PLI). These findings suggest that the P3 component in mice could share features of the human P300, in terms of stimulus processing correlates.2) In TASTPM mice, we analyzed changes in the AERPs, EROs and EEG. An increase in P3 latency and reductions in the amplitudes of N1, P2, and P3 components during target stimulus processing were found in these transgenic mice. Also, these mice exhibited increased delta and theta pre-stimulus activity associated to poor synchronization after the auditory stimulus, connectivity deficits between frontal and parietal sites, and a poor increase of theta total power for the target stimulus. Additionally, specific EEG abnormalities during non-REM sleep characterized by an increase in the power of theta, alpha and beta bands were detected. These findings support the hypothesis that in the TASTPM transgenic model, EEG, AERPs and EROs exhibit anomalies that reflect neural network disturbances typical of AD, and therefore, could be used as biomarkers in transgenic mouse models of AD.3) In WAG/Rij rats, we used electrical evoked potentials to study the interactions between the somatosensorial cortex and different thalamic nuclei, which constitute the cortico-thalamo-cortical system. We detected that the thalamic nuclei that belong to the somatosensorial loop and to the limbic loop have different patterns of electrical evoked responses that are intensity-dependent. In particular, very different responses were detected between the rostral and caudal parts of the thalamic reticular nucleus. These evoked responses reflect the diverse interaction of the hyperexcitable somatosensorial cortex on these circuits and hint the different role of the rostral and caudal parts of the reticular thalamic nucleus in the maintenance of sleep-wave discharges.4) In AJ/JAX mice, we described the sleep-wake architecture and characterized the spike-wave discharges. Our analysis suggest that this strain shows spike-wave discharges and disturbances in the sleep-wake architecture, that are equivalent to the hallmarks reported in patients with absence epilepsy and in genetic rat models. These results highlight the importance of EEG as translatable biomarker in preclinical models. Taken together, these findings strengthen our understanding of the properties of evoked potentials in rodents and support the view that the analysis of EEG signals will prove an invaluable tool, both in the investigation of neurosensory processing mechanisms and as a translational biomarker in studies of neurological diseases
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
Cosecha de peras y manzanas. Temporada 2018-2019. Características y pautas de manejo poscosecha - Abril 2019
Full text linkCaracterísticas climáticas generales de la temporada. El momento y las condiciones climáticas en las que se desarrolla la floración y posteriormente el cuaje de los frutos determinan su crecimiento y desarrollo. Para que estos procesos se desarrollen normalmente es necesaria una acumulación de horas de frio y una posterior acumulación de horas de calor.EEA Alto ValleFil: Calvo, Gabriela. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Alto Valle; ArgentinaFil: Colodner, Adrian Dario. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Alto Valle; ArgentinaFil: Rodriguez, Andrea Betiana. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Alto Valle; ArgentinaFil: Aragón, Jorge. JANUS S.A.; Argentin
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
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