1,720,972 research outputs found
Geomorphological, palaeoenvironmental and managerial implications for the conservation of the fossil forest at Titahi Bay
No full textThe remains of a Quaternary fossil forest consisting of broken off tree stumps retaining the normal characteristics of wood is preserved on the beachface and inner surf zone along the length of the shore at Titahi Bay Bench, on the west coast of the North Island, New Zealand. The tree stumps remain in-situ, within a mud of sheltered marine origin. The results of a luminescence date from this material indicate an age of deposition of 96.0 ± 10.7 ka. BP. Buried and preserved forests provide valuable palaeoenvironmental evidence for interpreting past climate and sea level shifts and several examples exists along New Zealand's coast. Due to the geographic location and popularity of the area as a recreational resource, the example at Titahi Bay provides interest to both quaternary scientists and coastal planners. Several issues regarding the use and management of the beach remain unresolved, and until now the significance and vulnerability to natural processes of the fossil forest has not been considered as part of the overall conservation of Titahi Bay Beach. This study provides a foundation from which future conservation plans can develop by focussing on quantifying the active processes which are operating in Titahi Bay and how these processes affect the exposure of the fossil trees.
The rate of deterioration of the tree stumps due to natural and human induced effects is proportional to the amount of tree stump exposure. Waves are the greatest contributing factor in determining the level of exposure at Titahi Bay, with wave generated currents being responsible for driving sediment transport within the bay. Development of a wave climate using historical wind data and wave hindcasting techniques indicate a mean breaker height of 0.9 m and closure depth of 2.4 m, showing for the great majority of the time, sediment transport is restricted to an area shoreward of the embayment entrance, thereby decreasing the opportunity for irrecoverable erosion to occur. Support for this theory is derived from extensive surveys of the beach topography in which sediment volume changes could be monitored on the beachface and inner surf zones over a nine month period. Episodes of beach rotation operating over periods of three to four weeks may be responsible for the alternating exposure of the forest from one end to the other in the short term. Breaker heights on the order of 1.1 m eroded sand from the southern end and deposited it at the northern end. The opposite transport pattern was recorded during the recovery phase.
Vertical bed elevation changes were far more significant in the middle of the beach than at the ends. Over longer time scales (three to four years) fluctuations in the Southern Oscillation Index may be responsible for the total volume of sand present on the beach face. An accumulation rate of 61 m3 per day was recorded during the study which was conducted during a strong La Niña phase which typically produces less wave generating energy for Titahi Bay. The strengthening of an El Niño phase will likely reverse this accumulation trend. Further study using a fully morphodynamic approach preferably during an El Niño phase is required to test the robustness of these observations.
Management issues at Titahi Bay are complex, particularly if it is decided to attempt to reduce the rate of deterioration of the fossil wood as part of an overall conservation plan. Implementation of such measures will inevitably cause conflict amongst the many different beach users, and it is essential to gain an understanding of the publics attitudes towards the beach as a recreational resource and area of scientific interest before such plans can proceed
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
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
The effect of earthquake induced relative sea level change on a gravel beach: Hawke's Bay, New Zealand
No full textThis thesis assesses the response of gravel beaches to relative sea level change. It focuses on morphological characteristics and surface and sub-surface sediments. The study also examines whether the 'Bruun Rule' can be applied to gravel beaches. During the 1931 Napier Earthquake a section of the Hawke's Bay, New Zealand coastline was uplifted (relative sea level fall) while an adjacent section was downthrown (relative sea level rise). This provides a unique opportunity to study how the signature of relative sea level changes of known amounts can be recognised on gravel beaches.
Observed shoreline movements, measured off aerial photographs, are directly related to land level changes from the Earthquake. Uplifted profiles have prograded at a rate of up to 0.89 m/yr and downthrown profiles have eroded at a rate of up to 1.33 m/yr. Shore normal movement dominates in the study area, while longshore drift plays an insignificant role in coastal change. Beach morphology, determined from survey profiles, indicates that storm berms in uplifted areas are higher than berms in downthrown areas, and that beaches in prograding uplifted areas are convex while eroding beaches are concave.
The appropriateness of the Bruun rule is assessed using a new conceptual sedimentary model. The model incorporates the effects of gravel size and shape sorting on sediment movement. It predicts that a relative sea level rise could be identified from a nearshore discontinuity and beachface sediments overlying nearshore sediments. Conversely, a relative sea level fall should be identified through a stranded storm berm, or outer frame sediments overlying offshore finer sediments. Observed shoreline movements in response to relative sea level change are 3-8 times greater than predicted by the Bruun Rule. This suggests that the unmodified Bruun Rule is not appropriate for gravel beaches.
Based on relative differences between grain size parameters, the beaches are divided into three surface sediment zones: upper-beach, mid-beach, and nearshore. The upperbeach zone is characterised by coarser grain size, lowest maximum projected sphericity (MPS), positive pebble skewness, and rounder pebbles. The mid-beach zone is characterised by finer grain size, higher MPS, negative pebble skewness, and more angular pebbles. The nearshore zone is characterised by coarser grain size, highest MPS, positive pebble skewness, and more rounded pebbles. The identification of these zones may help improve the understanding of sediment sorting and transport on gravel beaches.
Trenches were dug on two profiles to study the internal structure of the beaches. No direct evidence of the 1931 Earthquake is found in the internal structure of the beaches. However, many sub-parallel, planar beds and occasionally buried surface morphological features are observed. It is proposed that these structures are formed during large storm events. Consequently, a new conceptual model of bed emplacement under storm conditions is developed. This model merges sedimentological information from this study with the proposed wave mechanisms of Orford (1977)
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
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