ITC/USA 2007 Conference Proceedings / The Forty-Third Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2007 / Riviera Hotel & Convention Center, Las Vegas, Nevada / This paper introduced a fast scanning and waiting acquisition method for a DS/FH receiver used in the telemetry field. Mathematic model of the hybrid DS/FH system’s acquisition process is given and discussed. The average acquisition time expression using this method and generalized average acquisition time formula is derived also. The validity of the proposed algorithm is verified after simulation. In the circumstances of Additive Gauss White Noise for the channel, simulation result at Ec/N0= -15dB shows that the average acquisition time is decreased almost 4 times than that of waiting and searching method.

In this essay, I argue that Harry Frankfurt’s view of the domain of ethics is flawed. On Frankfurt’s view, what we care about falls outside the proper scope of ethics because we are bound to what we care about, not by the force of moral necessities, but by non-moral ‘volitional necessities’. I show, however, that being moved to care within the constraints of our volitional necessities requires meeting a moral obligation of self-honesty. Developing Kant’s idea of a duty to truthfulness, I show that the duty to truthfulness is a duty to self-honesty. I then contend that self-honesty is a moral duty because self-honesty is essential for self-respect. Thus, because we fulfill a moral obligation to ourselves in the course of caring about things within the constraints of our volitional necessities, what we care about is a moral matter within the domain of ethics.

Dans la société occidentale, la maîtrise ou non de la lecture a une influence majeure sur le fonctionnement d'un individu dans la société en influençant sa réussite scolaire et son insertion socioprofessionnelle. Dans ce mémoire, nous nous interrogeons à savoir quelles sont les habiletés langagières entrant en relation avec la compréhension en lecture. Une évaluation individuelle des processus d'identification des mots, de la compréhension orale et écrite de même qu'une évaluation du niveau de vocabulaire maîtrisé à l'oral ont été effectuées auprès d'adolescents âgés de 15 à 16 ans. Les analyses montrent que leurs difficultés de compréhension en lecture ne sont pas associées à des difficultés d'identification de mots, mais bien à une faiblesse au niveau du vocabulaire oral. Ces résultats vont dans le même sens que les recherches sur le sujet qui démontrent que le vocabulaire joue un rôle important dans la compréhension de texte chez les adolescents.

Thesis (MSc)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: Two fruit fly species, Ceratitis capitata (Wiedemann) and C. rosa (Karsch) (Diptera: Tephritidae) are known to attack deciduous fruit in the Western Cape Province of South Africa. The relative abundance of these two pests was studied in different kinds of fruit throughout the year. To facilitate field monitoring, using the immature stages, morphological differences between larval instars of C. capitata and C. rosa were investigated. Morphological characters of the larvae, such as the spiracles (anterior and posterior), mouth hooks and oral ridges were used. Many of these characters are only suitable to distinguish between the second and third instar larvae as these structures are not yet developed in the first instar larvae. Anterior spiracles were examined in terms of the number of tubules (papillae) and size or shape of the felt chambers. The number of papillae in both species was similar in the second and third instar larvae, but differed between the larvae of the two species (8-10 for C. capitata and 10-13 for C. rosa). In both species the felt chambers of the second instar larvae were narrow and elongate whilst those of the third instar larvae were broad and short. The major difference between the mouthhooks of the two tephritids was the presence of a sub-apical tooth in the third instar larva of C. rosa, being absent in the third instar of C. capitata. For the morphometric study, both laboratory-reared and field-collected specimens were examined. Measurements of the body dimensions (length and width) and various parts of the cephalopharyngeal skeleton (CPS) (mandible base, mandible length and distance between the tip and notch) were recorded in all three instars of both C. capitata and C. rosa. The data were analysed using finite mixture analysis (FMA-N1) and Levene's test was used to test for homogeneity of variances. The results of these analyses were used to estimate the frequency distributions of the larval measurements. In some cases overlaps in distributions were evident and were resolved using the same program, finite mixture analysis (FMA-N1), based on the probability of the overlapping measurements belonging to the designated instar (i.e. the one with highest probability). Determination of growth ratios suggested an approximate conformation to Dyar's rule thereby disputing the possibility of any hidden instar. However, in most cases measurements of the field samples did not conform to Dyar's rule. For the larval instars of C. capitata and C. rosa with overlapping morphological features, the morphometric approach as a distinguishing tool was demonstrated. In the field survey, the relative abundance of C. rosa at all experimental sites was very low in both orchards and adjacent vines. This suggested that this pest was either not a threat in these sites (crops) or the monitoring procedures applied, should be revised. Trap catches indicated high levels of infestation by C. capitata on some sites and low infestation levels at others. On the site with the highest population levels, activity peaks in the orchards did not co-incide with those in the adjacent vineyards. This suggested that these vineyards could be alternative hosts for fruit fly after the fruit in the orchards have been harvested. Forced oviposition (in vitro) studies indicated that Colombard (grown in Simonsvlei) was the most suitable host for survival of C. capitata. Other wine grape cultivars such as Chardonnay were also suitable for the total larval development of C. capitata. / AFRIKAANSE OPSOMMING: Twee spesies van die vrugtevlieg, Ceratitis capitata (Wiedemann) en C. rosa (Karsch) (Diptera: Tephritidae), val sagtevrugte in die Wes Kaap Provinsie van Suid- Afrika aan. Die groot hoeveelheid van hierdie twee plae op verskillende soorte vrugte is regdeur die jaar bestudeer. Voordat enige insekplaag gemonitor kan word, is dit belangrik dat die identiteit van die besondere plaag, insluitend sy onvolwasse stadiums, bekend moet wees. In hierdie studie word die morfologiese verskille tussen die larwe stadiums van C. capitata en C. rosa ondersoek. Kenmerke soos die spirakels (voor en agter), mondhake en mondriwwe is gebruik. Baie van hierdie morfologiese kenmerke kan net gebruik word om te onderskei tussen larwes in die tweede en derde stadiums omdat hierdie strukture nog nie in die eerste stadium ontwikkel is nie. Die voorste spirakels is ondersoek in terme van die aantal tubules (papillae) en die grootte en vorm van die vilt kamers. In beide spesies is die aantal papillae dieselfde vir die tweede en derde larwe stadiums, maar daar was en verskil tussen die larwes van die twee spesies (8-10 vir C. capitata en 10-13 vir C. rosa). In altwee spesies was die viIt kamers van die twee stadium larwes sma I en verleng, terwyl dit in die derde stadium larwes breed en kort was. Die hoof verskil tussen die mondhake van die twee vrugtevliee was die aanwesigheid van die subapikale tand in die derde stadium larwe van C. rosa, terwyl dit afwesig is in die derde stadium van C. capitata. Vir die morfometriese studie is voorbeelde van laboratorium geteelde vrugtevliee, asook vilee wat in die veld gevind is, ondersoek. Die liggaamsafmetings (Iengte en breedte) is gemeet asook die skelet (mandibel basis, mandibel lengte en die afstand tussen die punt en die kerf) in al drie stadiums van C. capitata en C. rosa. Die data is ontleed deur middel van eindige mengsel analise (FMA-N1) en Levene se toets is gebruik om vir homogeniteit en variansies te toets. Die resultate van die ontleding is gebruik om die frekwensie verspreiding van die larwale metings te skat. In sommige gevalle was daar oorvleueling en dit is opgelos met die gebruik van dieselfde program FMA-N1 baseer op die moontlikheid dat die metings wat oorvleuel, aan die aangeduide stadium (d.w.s die een met die hoogste waarskynlikheid) behoort. Die vasstelling van groei ratios dui aan dat dit naasteby ooreenstem met Dyar se reel en dus die moontlikheid van 'n versteekte stadium betwis. Maar in die meeste gevalle stem die veldmonsters nie ooreen met Dyar se reel nie. Die feit dat die morfometriese benadering die verrnoe het om larwale monsters met oorvleuelende morfologiese kenmerke, beteken dat dit kwalifiseer as In instrument om tussen die larwe stadiums van C. capitata en C. rosa te onderskei. Baie min C. rosa is in vrugteboorde en in nabygelee wingerde gevind. Dit dui of dat die plaag nie 'n bedreiging vir die vrugte inhou nie, of dat die monitor prosedures hersien moet word. Lokvalle dui aan dat daar 'n hoe vlak van infestasie van C. capitata in sommige gebeide is en In lae vlak in ander. Op die plek met die hoogste bevolking van vrugtevliee het die aktiwiteit in die boorde nie ooreengestem met die aktiwiteit in die nabygelee wingerde nie. Dit dui aan dat hierdie wingerde 'n alternatiewe blyplek bied aan die vrugtevliee nadat die vrugte in die boorde geoes is. Gedwonge oviposisie studies dui aan dat C. capitata die beste kan oorleef in Colombard (gekweek te Simonsvlei). Ander wyndruif kultivars is ook geskik vir die ontwikkeling tot by die laaste larwe stadium van C. capitata.

The proximity of the speciose South American continent to Trinidad and Tobago ensures that these islands have a rich and dynamic fauna. According to the equilibrium theory of island biogeography (MacArthur & Wilson 1967), these islands should be subjected to frequent immigrations from the nearby continent, and these additions will, in response, fuel local extinctions to maintain a balance of species richness. The aquatic habitat is further impacted by man's activities, (Government of Trinidad and Tobago 1962; Government of Trinidad and Tobago 1976b) which have the potential to amplify the natural rates of immigration and extinction. Despite the possible consequences, the effects of this disturbance on the fish fauna have not been studied. A survey of the islands' freshwater fishes was therefore carried out to investigate the natural spatial and temporal dynamics of local fish communities, and the effects of anthropogenic perturbations, on these. These baseline data can be used as a benchmark to address some of the problems that are threatening the fish diversity of Trinidad and Tobago. The fish fauna of Trinidad and Tobago is diverse. Total species richness was estimated at between 37 and 40. Four zoogeographic zones were recognised. A zone of Antillean fishes included Tobago and the north coast of Trinidad. A zone of recent colonising South American fauna existed along the south coast of Trinidad. The rest of Trinidad contained a relict South American fauna dating back to the time when Trinidad was still part of the mainland. Included here was a centrally located zone of unstable fauna at risk of local extinction. The fish fauna was temporally dynamic due to frequent colonisation and extinction events. Examination of the historic record showed that observed species richness varied from 38 to 43 between the mid 1950s and the present. During this time there were 15 introductions and 12 local extinctions. A conservative estimate was that a new species was recorded for Trinidad almost every three years. The geographic distribution of species also showed temporal changes which indicated a natural tendency of the fauna to vary over time. Human interference, particularly the introduction of exotic fish species and long-term habitat alteration, has affected species diversity. Forty seven percent of the new introductions and 43% of the extinctions were human-introduced exotics. About four fifths of sites in Trinidad, and almost one fifth of the sites in Tobago, were either perturbed or polluted. Polluted rivers coincided with areas of high urbanisation and industrial development in the west and southwest of Trinidad. Several effects of human interference on the fauna were recorded. Almost 8% of the sites examined contained one of the three exotic species still extant on the island. At each of these sites, the exotic species accounted for between 1.3% and 80.4%, by number, of the fish caught. Some of the effects of habitat disturbance on individual sites were increased frequency of diseases, extirpation of species, changes in species richness and other diversity measures, and the eventual regression of the fish community to opportunistic species (r-strategists). The potential of two fishes, Poecilia reticulata and Astyanax bimaculatus, as indicator species was examined. Astyanax showed better potential as an indicator of habitat quality as it was not found in depauperate communities, typical of severely disturbed habitats, and its proportional abundance and biomass were negatively affected by pollution. Poecilia populations, on the other hand, were found to be insensitive to habitat quality when the above-mentioned criteria were used. They did, however, have a high frequency of diseased individuals at polluted sites. One of the aims of conservation is to protect that portion of biodiversity most at risk of extinction, the rare species (Rabinowitz 1986). Over 70% of freshwater fish species found in Trinidad and Tobago were classified as rare in these islands. This fact, in addition to the loss of diversity recorded for some sites indicates that the implementation of a management strategy for the conservation of the freshwater fish fauna of Trinidad and Tobago is imperative. The management strategy should focus on the amelioration and protection of aquatic habitats since at least 80% of the rare species had either a restricted geographic distribution or narrow habitat specificity. Additionally, protection from overexploitation should be offered to commercially important species with only small populations. Finally, a minimum sample size of 35 sites, spread over different zoogeographic areas, is recommended for estimating species richness for monitoring, an intrinsic part of any management strategy.

published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy

published_or_final_version / Ecology and Biodiversity / Doctoral / Doctor of Philosophy

published_or_final_version / abstract / Computer Science / Doctoral / Doctor of Philosophy

Mosquitoes pose a serious threat to the economy, health status, and biosecurity of countries around the world. Mosquitoes kill an average of 700,000 people per year. The global expansion of air, sea, and land transport networks has greatly enhanced the spread of mosquitoes internationally. In the Pacific, the number of mosquito-borne diseases occurring has been on the rise in recent years, possibly as a result of human-mediated dispersal of larvae and adult mosquitoes. The Kingdom of Tonga has had numerous outbreaks of dengue fever and chikungunya virus in recent years. Previous research has catalogued species occurrences and distributions throughout Tonga. However, it is unknown whether new species have arrived in Tonga, and if distribution of previously found species has changed since the last comprehensive survey in 2006. Present research aims to update the literature by conducting a mosquito survey at 84 sites across the four islands of Tongatapu, Pangaimotu, ‘Oneata, and ‘Eua to record the distribution and occurrence of mosquito larvae. Nine mosquito species were collected: Aedes aegypti Linnaeus, A. albopictus Skuse, A. tongae Edwards, A. horrescens Edwards, A. vexans nocturnus Theobold, Culex annulirostris Skuse, C. albinervis Edwards, C. quinquefasciatus Say and C. sitiens Wiedemann. The collection of A. albopictus is the second time that this species has been recorded in Tonga. Moreover, the spatial extent of this species throughout Tonga was far greater than previously recorded. A major outcome of this survey has been the creation of an identification key for the mosquito larvae species of Tonga. This key should increase the accuracy of positive mosquito larvae identifications in Tonga. Mosquitoes were more frequently collected in artificial (e.g., used car tyres, fuel drums, containers) than natural (e.g., pools, ponds, tree holes) habitats. Car tyres, water containers, fuel drums, fridges, washing machines, and ponds were the most common habitats in which mosquito larvae were found. Aedes aegypti, A. albopictus, and C. quinquefasciatus were the three most common mosquito species collected, whereas A. tongae, A. horrescens, A. vexans nocturnus, C. annulirostris, C. sitiens, and C. albinervis were less frequently found. Multiple logistic regression analyses indicated that habitat volume had a significant positive effect on the presence of A. albopictus and A. tongae, whereas conductivity had a significant positive effect on the presence of C. annulirostris. Additionally, the volume by temperature interaction was a significant predictor of species presence for A. aegypti, A. albopictus, and C. annulirostris (as habitat volume increases, the effect of temperature went from neutral to negative). This suggests that larger, cooler habitats favour colonisation by these species. The number of artificial habitats (particularly used car tyres) present may have significantly increased since previous studies. Management should therefore focus on implementing community-run mosquito projects aimed at reducing the number of artificial habitats capable of being colonised by mosquito larvae. Covering, tipping out water, and infilling these habitats with soil to prevent mosquito oviposition is a pragmatic and straightforward mosquito control solution. This should immensely reduce the abundance of mosquitoes and may prevent disease outbreak in Tonga.

Recent emphasis by NASA on returning astronauts to the Moon has placed attention on the subject of lunar surface feature tracking. Although many algorithms have been proposed for lunar landmark tracking navigation, much less attention has been paid to the issue of navigational state initialization from lunar craters in a lost in low lunar orbit (LLO) scenario. A new crater detection and identification algorithm is developed in this dissertation that allows for navigation state initialization from as few as one image of the lunar surface with no a priori state knowledge. Craters are detected by a filter that is an extension of the Circular Hough Transform, after which verification is performed by a number of checks on the illuminated portion of the candidate crater interior. Detected craters are identified by matching them to entries in the USGS crater catalog via non-dimensional crater triangle parameters. False identifications are rejected based on a probability check. The algorithm was tested on Apollo 16 LLO images, and shown to perform well. / text