The rare and elusive wood-living beetle Tragosoma depsarium, once widespread all over Sweden, is associated with large, sun-exposed pine logs required for breeding. Due to modern forestry and fire suppression, this type of substrate has become so rare in the landscape that the beetles’ existence in Sweden is threatened. Recently, the female sex pheromone of this species was synthesised, providing a new method to monitor beetle populations using pheromone traps. Such a method was used in the current study to relate the presence-absence of T. depsarium with different landscape variables at different scales; 100, 500, 1000 and 2000 meters, respectively. The occurrence of T. depsarium in Östergötland County was associated with the amount of protected areas and clear-cuts at 500 and 1000 meters, respectively. Additionally, the amount of pine forest within 2000 m from the trap showed a weak, positive effect on the number of beetles. In the whole south-east boreo-nemoral zone of Sweden, a positive correlation between beetle occurrence and protected areas were found at 2000 m together with a negative correlation for volume pine wood within 100 m. Also, emergence holes on pine logs around each trap were strongly associated with beetle occurrences. To conclude, using pheromone traps were an easy way of detecting beetles. Although the number of caught T. depsarium varied greatly over time, the sampling period matched the flight period well. For long-term survival of this beetle, the forests must contain breeding substrates and be opened up through prescribed burning, selective cutting and active forestry.

In a series of works, Jun-Muk Hwang and Ngaiming Mok have developed a geometric theory of uniruled projective manifolds, especially those of Picard Number 1, relying on the study of Varieties of Minimal Rational Tangents (VMRT) from both the algebro-geometric and the G-structure perspectives. Based on this theory, Ngaiming Mok and Jaehyun Hong studied the standard embedding between two Rational Homogeneous Spaces (RHS) associated to long simple roots which are of different dimensions. In this thesis, I consider admissible pairs of RHS (X0, X) of Picard number 1 and locally closed complex submanifolds S ⊂ X inheriting VMRT sub-structures modeled on X0 = G0/P0 ⊂ X = G/P de_ned by taking intersections of VMRT of X with tangent space of S. Moreover, if any such S modeled on (X0, X) is necessarily the image of a standard embedding i : X0 → X, (X0, X) is said to be rigid. In this thesis, it is proved that an admissible pair (X0, X) is rigid whenever X is associated to a long simple root and X0 is non-linear and de_ned by a marked Dynkin sub-diagram. In the case of the pair (S0, S) of compact Hermitian Symmetric Spaces (cHSS), all the admissible pairs (S0, S) are completely classified. Based on this classification, a sufficient condition for the pair (S0, S) to be non-rigid is established through explicitly constructing a submanifold S ⊂ S such that S can never be obtained from the image of any standard embedding i : S0 → S. Besides, the term special pair is coined for those (S0; S) sorted out through classification, and the algebraicity of submanifolds modeled on special pairs is confirmed by checking a modified form of the non-degeneracy condition defined by Hong and Mok is satisfied. However, the question as to whether these special pairs are rigid, as pointed out in this thesis, remains to be investigated. Finally, pairs of hyperquadrics (Q^n, Q^m) are studied separately. Since non-rigidity is trivial, in these cases it is interesting to establish a characterization of the standard embedding i : Q^n→Q^m under some stronger condition. In this thesis, the latter problem is solved in terms of the partial vanishing of second fundamental forms. / published_or_final_version / Mathematics / Doctoral / Doctor of Philosophy

This thesis presents observational studies of long-term and extreme variability of stars with the Digital Access to a Sky Century@Harvard (DASCH) project. Stellar variations over decades are poorly explored. With the unique 100 years coverage of DASCH, for the first time, we are able to study the variable sky over long timescales in a systematic way. I have developed photometric calibration and variable search algorithms for DASCH. I have discovered exciting new types of long-term variables, which do not match any of the common classes, and studied the physical processes involved. Following a brief introduction on variable stars and DASCH in the first chapter, I describe my work on DASCH pipeline, including photometric development and defect filtering in chapter 2. I present our discovery of a group of peculiar long-term K giant variables with \(\sim1\) mag variations over decades in chapter 3. Follow-up observations show that they consist of two subgroups, including a subgroup of RS CVn binaries with strong magnetic activity, and another subgroup of single stars. In both cases, the variation amplitudes and timescales are abnormal, and may be related to either ultra strong star spots, or novel dust formation processes. In chapter 4, I present the discovery of a 5 yr dip around 1900 in the eclipsing binary KU Cyg consisting of a F star and a K giant, which is related to the accretion disk surrounding the F star. It showed a slow fading \((\sim 4 yr)\), which is probably caused by increases in dust extinction in the disk, and a relatively fast brightening \((\sim 1 yr)\), which may be due to the evaporation of dust transported inward through the disk. The extinction excess which caused the fading may arise from an increased mass transfer rate in the system or from dust clump ejections from the K giant, in accordance with K giant “dimming” as discussed above. In chapter 5, I present a 10 yr nova-like outburst in a peculiar symbiotic system. With P = 119 days, it is interestingly located in the period gap region between classical novae and symbiotic novae. The most probable explanation of the outburst is hydrogen shell-burning on the white dwarf (WD) without significant mass loss, which suggests a promising new channel for Type Ia Supernovae (SNe). In chapter 6, I present the DASCH light curves of Kepler planet-candidate host stars. We found no variation for these host stars. In chapter 7, I present my variable search algorithms and the resulting DASCH variable catalog for the Kepler field. The conclusion is presented in chapter 8. / Astronomy

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No description available.

Separata del curso Estadística Aplicada 1 (MA131), que corresponde al ciclo 2013-1. Contenido: 1. Estadística: estadística descriptiva e inferencial. 2. Definiciones básicas. 3. Escala de mediciones: escala nominal, escala ordinal, escala de intervalos y escala de razón. 4. Tipos de variables: variables cualitativas y variables cuantitativas. 5. Problemas resueltos de conceptos básicos. 6. Problemas propuestos de conceptos básicos.

Separata del curso de Estadística para Ingeniería 1 (CE54 / CE56), que corresponde al año 2013. Este curso es una asignatura destinada al análisis estadístico.

Cuaderno de trabajo del curso Estadística Aplicada 1 (MA131), que corresponde al ciclo 2013-2. Contenido: 1. Estadística: estadística descriptiva e inferencial. 2. Definiciones básicas. 3. Escala de mediciones: escala nominal, escala ordinal, escala de intervalos y escala de razón. 4. Tipos de variables: variables cualitativas y variables cuantitativas. 5. Problemas resueltos de conceptos básicos. 6. Problemas propuestos de conceptos básicos.

Le contexte actuel dans lequel opèrent les enseignes de grande distribution est caractérisé par un besoin de légitimité, de compétitivité et de différenciation. Dans ce contexte, nous observons deux phénomènes : d'une part un engouement des différents acteurs pour l'argument socialement responsable et d'autre part, un rôle de plus en plus important donné aux marques de distributeurs dans les stratégies de différenciation suivies par les enseignes. L'objectif de cette recherche est de déterminer les réponses des consommateurs à la qualité sociale de la MDD parce qu'elle est la garantie du respect des droits humains et des travailleurs tout au long du processus de fabrication et de commercialisation des MDD. Une expérimentation menée auprès de 800 individus représentatifs de la population française montre que communiquer la qualité sociale de la MDD améliore de façon significative la qualité perçue de la MDD et la fidélité intentionnelle des consommateurs à la marque et à l'enseigne (fidélité globale). La compétitivité des Marques De Distributeur semble avoir le pouvoir explicatif le plus important de la qualité perçue et de la fidélité globale du consommateur. En outre, les réponses positives des consommateurs à la qualité sociale de la MDD semblent motivées par les valeurs d'universalisme qui sont plus saillantes pour les consommateurs engagés socialement que pour les autres.

A haptic system is a robotic computer interface which aims to provide tactile feedback for human operators when they manipulate virtual environments (VEs) or remote environments (REs). The tactile feedback is emulated by applying forces, vibrations, or motions to the human users through a haptic device/interface, e.g. a robot arm. Transparency and stability are two important criteria for designing a haptic system. Transparency is related to the realism of user's touch sensation and stability guarantees the safety of the user while interacting with VEs/REs. Because of the nature of the human tactile sensory system, a transparent haptic system demands an update rate greater than 500 Hz, i.e. most commercial haptic devices work at 1 KHz. On the other hand, many haptic applications are multirate systems. The multirate property of a haptic system is due to either the slow update rate of the VE or the impairments of computer networks such as limited transmission bandwidth or packet loss. Wave transformation is wildly used in teleoperation to cope with both constant and varying time delays. This work aims to use wave transformation to tackle the challenges imposed by multirate property of a haptic system. First, passive multirate wave variables control (PMWVC) is introduced. PMWVC guarantees the passivity of the communication channels through which the fast haptic device is connected to the slow VE/RE. It is shown that to maintain the passivity of the system, aliasing should be avoided in the communication channels, i.e. by using anti-aliasing filters. Next, PMWVC strategy is applied to two different applications: i) multiuser cooperative haptics and ii) haptic interaction with an unknown VE. In the first application, two users at two different locations manipulate a common virtual object simulated on a central server. The users are connected to the central server through a LAN network. The second application is a single user application in which PMWVC is used to connect the haptic device to an unknown slowly updated VE. Since in this application the VE is unknown, the computational delay of the VE significantly affects the stability of the overall system. To tackle this problem, a nonlinear algorithm based on passivity analysis is proposed. In both examples, numerical and experimental results validating the analytical results are provided. The results show that by using PMWVC, it is possible to significantly improve the performance of a multirate haptic system in terms of transparency and stability. The second half of this work is devoted to improving the performance of PMWVC in all frequency ranges. In order to study the performance of PMWVC, lifting is used to convert the multirate haptic system to a unirate system. By using this technique, it is shown that velocity estimation plays a critical role in a haptic application with PMWVC, especially in high frequencies. Considering this fact, a method for designing a passive velocity filter in wave domain is proposed. Finally, a filter bank structure is introduced which enables utilizing a local model in conjunction with PMWVC. In this structure, the outgoing signal sent to the VE is split into two frequency ranges. Low frequency content of the signal is fed to the original VE and high frequency content of the signal is sent to the local model. By using lifting the performance of the proposed structure is studied. The results show that the proposed method improves the transparency of the system in all frequency ranges and unlike utilizing a local model in power domain, it does not impose any restriction on the stability of the system. / Graduate / 0548 / 0544 / 0771 / nyasrebi@uvic.ca