758 research outputs found
Zygonyx annika Dijkstra, sp. nov.
No full textZygonyx annika Dijkstra sp. nov. – Annika’s Cascader (Type Photo 58, Photo 75, Fig. 35) Taxonomy Variation in markings and male genitalia suggests that a complex exists of species similar to Z. flavicosta (Sjöstedt, 1900), but thus far only Z. geminuncus Legrand, 1997 has been separated. Morphology and COI data suggest that at least six species are involved, with two or even three occurring in close proximity. Variation among specimens nearest to the true Z. flavicosta is so great that we only name three species that can be separated from sympatric relatives by both genetics and morphology (Tree 10). The present taxon is known only from a pair caught in copula, which overlaps geographically with morphologically and genetically distinct populations that were identified as Z. flavicosta. Material studied Holotype ♂ . RMNH.INS.503187, Sierra Leone, Eastern Province, 40 km SW of Kenema, Moa River at Tiwai Island, forested island in large river with rocky rapids (Photo 75), 122 m a.s.l. (7.551 ° N 11.3549 ° W), 14 -iii- 2011, leg. K.-D.B. Dijkstra, RMNH. The right Hw and leg are aberrant in shape, which is probably a developmental defect. Further material. SIERRA LEONE (Eastern Province): 1 ♀ (RMNH.INS.503188), in copula with holotype, RMNH. Genetics One unique haplotype (n = 2) is distinct and nearer to Z. dionyx sp. nov. and Z. geminuncus than the morphologically similar Z. flavicosta (Tree 10). Male morphological diagnosis Belongs to the flavicosta -complex by (a) the modest size, Hw 36.5 mm (n = 1); (b) the moderately dense venation, with 13 ½– 14 Ax in Fw; (c) the largely black hind legs; (d) the pointed and forward-curved apex of the anterior lamina (Fig. 35); and (e) the pale dorsal band on S 7 that stands out against the largely dark S 5–6. Differs from the sympatric Z. flavicosta by (1)the dorsum of the eyes being deep reddish brown, contrasting with their greyish underside, rather than uniformly grey-blue; and (2) the shorter hook of hamule, which is less than a third as long as the hamule is wide (Fig. 35). Also differs from Z. flavicosta from Sierra Leone, Liberia and Gha- na by (3) the Hw membrane being darkly stained and not clear beside the membranule; (4) the more continuous pale thoracic markings, the stripe on the metepisternum not being broken between the metastigma and wing base, while that on the metepimeron is not invaded by black posteriorly to appear T-shaped; and (5) the straighter cerci (Fig. 35). Etymology Named in honour of Dr Annika Hillers, who advanced research on the Gola rainforest ecosystem and enabled the author to make his contribution (noun in apposition). Range and ecology Rocky fast-flowing section of the large Moa River in Sierra Leone, flanked by gallery forest and about 120 m a.s.l. Similar adults and possible exuviae were seen near Kenema 35 km upstream, but Z. flavicosta is sympatric and possibly syntopic.Published as part of Dijkstra, Klaas-Douwe B., Kipping, Jens & Mézière, Nicolas, 2015, Sixty new dragonfly and damselfly species from Africa (Odonata), pp. 447-678 in Odonatologica 44 (4) on pages 661-665, DOI: 10.5281/zenodo.3538
Implementation of the Dijkstra Algorithm in Finding the Shortest Route to Al-aziziyah Islamic Boarding School – Ldii in Samarinda
No full textGlobalization Technology is growing very rapidly uncontrollably, the ease of use of technology is supported by the many emerging technology tools that are very easy to obtain, even some technology tools sold at very affordable prices. Android technology installed and packed in the form of smartphones is familiar to use even among people who are marginalized in the corners of the region. Not only are the intellect literate with technology utilizing the ease and development of this technology, even the lay people who utilize the internet network and are familiar with google can also mark the location of its place on google maps. With the globalization of this technology, the author will use the Implementation of Alghorithm Dijkstra In Finding the Shortest Route from the author's residence to Al-Aziziyah Islamic Boarding School – Ldii Di Samarinda. In this study, algorithm Dijkstra used alghorithm in determining the shortest path from the starting point to the destination point in a graff or shortest path with the help of LBS (Location Based Service), GPS, Google Maps, and Graff then found the shortest path was 4.88 km
Motivational Social Visualizations for Personalized E-Learning
No full textA large number of educational resources is now available on the Web to support both regular classroom learning and online learning. However, the abundance of available content produces at least two problems: how to help students find the most appropriate resources, and how to engage them into using these resources and benefiting from them. Personalized and social learning have been suggested as potential methods for addressing these problems. Our work presented in this paper attempts to combine the ideas of personalized and social learning. We introduce Progressor + , an innovative Web-based interface that helps students find the most relevant resources in a large collection of self-assessment questions and programming examples. We also present the results of a classroom study of the Progressor + in an undergraduate class. The data revealed the motivational impact of the personalized social guidance provided by the system in the target context. The interface encouraged students to explore more educational resources and motivated them to do some work ahead of the course schedule. The increase in diversity of explored content resulted in improving students’ problem solving success. A deeper analysis of the social guidance mechanism revealed that it is based on the leading behavior of the strong students, who discovered the most relevant resources and created trails for weaker students to follow. The study results also demonstrate that students were more engaged with the system: they spent more time in working with self-assessment questions and annotated examples, attempted more questions, and achieved higher success rates in answering them
Evolution of morphology in solidifying aluminium alloys
No full textIn the thesis two different models of solidification of aluminum alloys are presented and analyzed. The first 1--D solidification model is derived from the conservation of solute, heat and mass. With numerical experiments it is shown that simulations with the Finite Difference discretization must adhere a relation similar to the Courant-Friedrichs-Lewy relation in order to get numerical stable solutions. Furthermore, it is demonstrated that depending on the chosen discretization of the interface conditions an additional singularity which can destroy stability occurs. The occurrence of this singularity is not related to the Finite Difference discretization. Singularities are also found with application of the Collocation Method. An example of a solidifying aluminum slab is successfully solved with application of the model equations and avoiding stability infringements. The possibility to apply the model in an extended simulation, i.e. especially in the second solidification model, is discussed. The second new 2--D solidification network model is used to simulate fluid flow and solidification within the mush. It is based on the assumption that the liquid parts of the mush can up to some degree be represented by a network of geometrical simplified liquid channels. Numerical simulations with this model indicate that conduction and convection of heat and solute affects directly only the permeability of a small region of the mush. Self induced effects and the formation wormholes have not been found. Finally, a detailed study of the influence of various model parameters of the network model is presented. A more detailed abstract is included within the thesis.Mechanical Maritime and Materials Engineerin
Metabolism, oxidative stress and territorial behaviour in a female colour polymorphic cichlid fish
No full textIntrasexual selection on body coloration is thought
to play an important role in the evolution of colour polymorphism,
but its physiological underpinnings have received limited
attention. In the colour polymorphic cichlid Neochromis
omnicaeruleus, three fully sympatric female colour morphs—
a plain morph (P) and two conspicuously coloured blotched
morphs, black-and-white blotched (WB) and orange blotched
(OB)—differ in agonistic behaviour. We compared routine
metabolic rate (when females were housed in social isolation),
short-term energetic costs of interacting with a same-colour
rival housed in an adjacent transparent chamber and oxidative
stress between the three female colour morphs. WB females
had a lower routine metabolic rate compared with the other
colour morphs. WB females also had a lower active metabolic
rate during inter-female interactions than OB females, while
OB females used more oxygen per unit aggressive act than the
other two colour morphs. However, there were no consistent
differences in oxidative stress between the three morphs.
Concerted divergence in colour, behaviour and metabolism
might contribute to the evolution of these polymorphisms in
sympatry
City branding: A new start for Dutch city centres?: A research of attractiveness by the cities Hoorn and Roermond.
No full textCity branding is one of the new marketing strategies for cities. Citybranding is a comprehensive phenomenon with the main goal of setting out the city with a brand; to profile the city with an identity. The objective of this research is to investigate the phenomenon city branding and to clarify if city branding gives the city a new impulse of attractiveness. This investigation is tested on two cities, Roermond and Hoorn. The research question is: “Does citybranding offer medium-sized city centres new impulses of attractiveness?”Real Estate & HousingArchitectur
Are language production problems apparent in adults who no longer meet diagnostic criteria for attention-deficit/hyperactivity disorder?
No full textIn this study, we examined sentence production in a sample of adults (N = 21) who had had attention-deficit/hyperactivity disorder (ADHD) as children, but as adults no longer met DSM-IV diagnostic criteria (APA, 2000). This “remitted” group was assessed on a sentence production task. On each trial, participants saw two objects and a verb. Their task was to construct a sentence using the objects as arguments of the verb. Results showed more ungrammatical and disfluent utterances with one particular type of verb (i.e., participle). In a second set of analyses, we compared the remitted group to both control participants and a “persistent” group, who had ADHD as children and as adults. Results showed that remitters were more likely to produce ungrammatical utterances and to make repair disfluencies compared to controls, and they patterned more similarly to ADHD participants. Conclusions focus on language output in remitted ADHD, and the role of executive functions in language production
Entropic collapse transition of a polymer in a solvent with a nonadditive potential
No full textWe use molecular dynamics simulations to study an entropy-driven collapse transition of a flexible polymer in a solvent. Monomers and solvent particles interact with a steeply repulsive soft-sphere potential. We consider a nonadditive potential system in which the effective diameter describing the solvent-monomer interaction is greater than or equal to the diameters corresponding to the solvent-solvent and monomer-monomer interactions, which are set equal. We examine the effects of nonadditivity of the solvent-monomer potential and solvent density on the collapse transition. We find that a small degree of nonadditivity will drive the transition at sufficiently high solvent density. Increasing the density leads to a collapse transition at lower values of nonadditivity. [S1063-651X(99)06609-X].PT: J; CR: CATES ME, 1988, J PHYS-PARIS, V49, P2009 DIJKSTRA M, 1994, J CHEM PHYS, V101, P3179 DIJKSTRA M, 1994, PHYS REV LETT, V72, P298 EDWARDS SF, 1988, J CHEM PHYS, V89, P2435 ESCOBEDO FA, 1996, MOL PHYS, V89, P1733 FRENKEL D, 1992, PHYS REV LETT, V68, P3363 LUNABARCENAS G, 1996, J CHEM PHYS, V104, P9971 SUEN JKC, 1997, J CHEM PHYS, V106, P1288 WU D, 1992, J CHEM PHYS, V96, P835; NR: 9; TC: 5; J9: PHYS REV E; PG: 3; GA: 239PHSource type: Electronic(1
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