1,721,127 research outputs found
Telemetry tails: a practical method for attaching animal-borne devices to small vertebrates in the field
Full text linkContext. Continued miniaturisation of tracking technology increases its utility in animal applications. However, species morphology often dictates the type of animal-borne device (ABD) that can be used, and how it is attached. The morphology of species within Peramelemorphia preclude them from the standard collar attachment of ABDs for terrestrial mammals. Aims. This paper describes a method for the tail-mount attachment of ABDs, and deployment results for Peramelemorphia across arid, semi-arid and temperate Australia to (a) test the performance of attachments and ABDs in the field and (b) discuss the animal welfare considerations for this attachment method. Methods. Tail-mount attachment of ABDs were field-tested on a total of 80 greater bilbies (Macrotis lagotis), and 14 long-nosed bandicoots (Perameles nasuta). Key results. Time to natural detachment (TTND) was between 2 and 52 days, with 65.74% (142 of 216) remaining on until manual removal. For ABDs that were manually removed, attachments were retained for up to 94 days. The method used for tail-mount attachment of ABDs to long-nosed bandicoots resulted in significantly shorter TTND compared with the method used for bilbies, and environmental factors (high temperatures and rainfall) had a negative effect on TTND. Tail-mount attached global positioning system (GPS) sensors collected large quantities of accurate data, with a maximum fix success rate of 83.38%. Damage to GPS (antenna breakage and water ingress) during deployment, however, impacted performance. In environments with frequent rainfall and waterlogged soils, the tape on a small proportion (6.25%) of (n = 192)attachments to bilbies caused tail injury. All injuries were resolvable, with most requiringminimal to no veterinary intervention. Key conclusions. Attachment longevity can be affectedby how the ABD is mounted to the tail, the species and the deployment environment. Theenvironment can also affect which adhesive tapes are suitable for ABD attachment. However, thismethod is highly modifiable, practical for field application and can have long retention timesrelative to other temporary methods. Implications. This ABD tail-mount attachment methodadds another tool to the telemetry tool-kit, with all the benefits of a low-tech, low-cost, passivedrop-off type attachment. This method has demonstrated practicality for Peramelemorphia, withpotential application to other suitable small vertebrates
Non-chemical control of the Red-billed Quelea (Quelea Quelea) and use of the birds as a food resource
Full text linkThe Red-billed Quelea Quelea quelea is the most numerous terrestrial bird and the most destructive avian pest of small-grain crops throughout sub-Saharan Africa. The birds occur in 60% of the cereal production areas of Tanzania almost every year. Quelea can cause serious local damage to millet, rice, wheat and sorghum and cause considerable hardship to subsistence farmers. Spraying with the organophosphate avicide Queletox®, (60% fenthion a.i.) remains the preferred control measure despite its negative impact on the environment and high cost. As an alternative control measure, the mass trapping of quelea and harvesting their chicks to use both as a source of protein and for income generation was investigated. Two traps using very large nets, based on designs used successfully to catch birds in Tunisia and the USA, failed with quelea; but success was achieved with four other methods. With traditional basket traps made of grass, an average of 286 birds could be caught per trap per day, this increased to 574 birds by using a replica wire mesh version. When using mist nets in a breeding colony the number of birds caught per day per 12 m long net varied from 445 for the first day to 231 on the tenth day. Trials with a roost trap yielded 5,000 to 17,000 birds per day. Cooking and preservation methods were investigated to maximise the potential utilization of quelea meat as a food resource. The best preservation method was achieved by boiling with added salt and drying, while the cooked product rated most highly by volunteer tasters was fresh meat. Proximate analysis was conducted on preserved, milled, quelea meat which confirmed the highly nutritive value of quelea for human consumption. It was concluded that mass-trapping and chick harvesting methods were more environmentally friendly control methods than spraying or use of explosives, with the added benefits of providing high-quality proteinaceous, uncontaminated, food and income generation for the trappers and their families
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
Efficacy of indigenous pesticidal plants for tomato and brassica pest management in Malawi
Full text linkThe cultivated tomato, Lycopersicon esculentum, and rape (Brassica napus) are the most important horticultural vegetable crops grown in southern Africa. However, their production is highly constrained by insect pests including red spider mites Tetranychus evansi and the aphids (Brevicoryne brassicae and Myzus persicae). The results on field surveys revealed that majority of smallholder farmers have considerable knowledge about pesticidal plants and reported Tephrosia vogelii, Vernonia amygdalina, Tithonia diversifolia and Azadirachta indica as particularly important. T. vogelii was the most popular species in Zambia (60.7%) and Malawi (53.4%) while brassicas constituted 34% and 44% of all vegetables grown in Malawi and Zambia respectively. Although insect pest infestation during the field trials was low but nonetheless, significant differences were observed between pesticidal plant extracts treated plots and the control. Use of pesticidal plants resulted in significantly lower damage to vegetables. The results further revealed that pesticidal plant products as compared to untreated control decreased the incidence of red mites, aphids and diamond back moth significantly. Although synthetic insecticides were most effective against these pests, the pesticidal plant extracts examined offered valuable contribution to pest management efforts. T. diversifolia was the most effective at reducing numbers of both red spider mites and aphids followed by T. vogelii. Crude extracts applied at a concentration of 10% w/v reduced effect onthe abundance of red spider mites and aphids significantly (P<0.001) when compared to control treatment. All the plant extracts tested had some level of toxic effect at 4% w/v. Yields of tomato treated with pesticidal plants ranged from 24,414 to 38,320 Kg ha-1 compared to control plots (21,590 Kgha-1). Vegetable damage due to levels of insect pest (aphids, red mites and diamondback moth) infestation varied from 6 to 45%. T. vogelii was a promising species in field and laboratory trials and analysis of the extracts identified several rotenoids as the biologically active components. Laboratory studies showed for this first time that the rotenoids tephrosin and deguelin were toxic against red mite and aphids. However, field experimentation with T vogelii showed that compounds were not present on the leaf surface when applied on bean leaves indicating total degradation of the compounds under the sun after three days. The study has also shown that there is substantial temporal and spatial variation in the occurrence of these rotenoids, which might affect harvesting protocols. Pesticidal plant extracts can improve vegetable production for resource poor farmers at controlling vegetable pests at much reduced costs as claimed by farmers since most plant materials are found locally or can easily be cultivated
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
- …
