Physical inactivity is a significant issue in the United States that has been linked to multiple health concerns. Few studies have used behavioral interventions during opportunities available in school, such as recess. There is a need for low effort and accessible interventions to increase children’s physical activity during these opportunities. The purpose of the current study was to evaluate the efficacy of a peer-implemented recess intervention that uses student pairing and feedback to increase physical activity. Step count was recorded by a pedometer. Peer leaders were trained in a group using behavioral skills training. A new leader performed the task-analyzed duties each week of intervention. An ABAB reversal design was used to evaluate the efficacy of the intervention. The results were mixed across the participants, but generally this study did not achieve experimental control in an ABAB design.

Drosophila male is an example of achiasmatic meiosis which lacks crossingover and chiasmata during meiosis. Previous studies showed that homologous pairing of both euchromatin and centromeres is lost during middle prophase I, however, homologs are still connected as they form bivalents. The X-Y pair utilizes a specific repeated sequence within the heterochromatic ribosomal DNA blocks as a pairing site. No pairing sites have yet been identified for the autosomes. To search for such sites, we utilized probes specifically targeting heterochromatin regions to assay pairing sequences and behavior in meiosis by fluorescence in situ hybridization (FISH). We found that the fourth homologs pair at the heterochromatic region 61 and associate with the X chromosome throughout prophase I. The pairing of the fourth homologs is disrupted in the homolog conjunction complex mutants. Conversely, six tested heterochromatic regions of the major autosomes (second and third chromosomes) have proved to be largely unpaired after early prophase I. This suggests that pairing mechanism of the major autosomes may differ from the sex and fourth chromosomes; stable connections between major autosomal homologs might occur at different sites along chromosomes in different cells by analogy to chiasmata. Moreover, FISH analysis also revealed two distinct patterns of sister chromatid cohesion in heterochromatin: regions with stable cohesion and regions lacking cohesion, suggesting that sister chromatid cohesion is incomplete within heterochromatin but with preferential sites in male meiosis.Modifier of Mdg4 in Meiosis (MNM) and Stromalin in Meiosis (SNM) are components of homolog conjunction complex and essential for homolog pairing and segregation in male meiosis. Using yeast two-hybrid assay and co-immunoprecipitation, we showed that the MNM and SNM interact with each other. Specifically, the BTB domain of MNM is responsible for the interaction with SNM, whereas FLYWCH domain of MNM is crucial for this interaction but does not directly interact with SNM. Additionally, point mutation analysis revealed that L9K replacement of the BTB domain weakened the MNM-SNM interaction and caused high frequencies of chromosome nondisjunction. In conclusion, these results provide a biochemical basis for the mechanism of homolog pairing and support the role of homolog conjunction complex in male meiosis.

Bilinear pairings on elliptic curves have many cryptographic applications such as identity based encryption, one-round three-party key agreement protocols, and short signature schemes. The elliptic curves which are suitable for pairing-based cryptography are called pairing friendly curves. The prime-order pairing friendly curves with embedding degrees k=3,4 and 6 were characterized by Miyaji, Nakabayashi and Takano. We study this characterization of MNT curves in details. We present explicit algorithms to obtain suitable curve parameters and to construct the corresponding elliptic curves. We also give a heuristic lower bound for the expected number of isogeny classes of MNT curves. Moreover, the related theoretical findings are compared with our experimental results.

Mental causation between the material and the immaterial has been problematic for interactionist substance dualism ever since its first major proponent René Descartes. The contemporary philosopher Jaegwon Kim believes he has found an argument that shows exactly why an immaterial event cannot be said to cause a material event; he calls this the pairing problem argument. This thesis will argue that there is actually sufficient empirical evidence to suggest that Kim’s argument is unsuccessful due to one of its premises being false. Furthermore, this thesis will also argue that interactionist substance dualism is actually a philosophically viable alternative, and lastly ways are sketched of how one might go about constructing such a view responsibly.

It was recently discovered by Joux [30] and Sakai, Ohgishi and Kasahara [47] that bilinear maps could be used to construct cryptographic schemes. Since then, bilinear maps have been used in applications as varied as identity-based encryption, short signatures and one-round tripartite key agreement. This thesis explains the notion of bilinear maps and surveys the applications of bilinear maps in the three main fields of cryptography: encryption, signature and key agreement. We also show how these maps can be constructed using the Weil and Tate pairings in elliptic curves.

Bilinear pairings on elliptic curves have many cryptographic applications such as identity based encryption, one-round three-party key agreement protocols, and short signature schemes. The elliptic curves which are suitable for pairing-based cryptography are called pairing friendly curves. The prime-order pairing friendly curves with embedding degrees k=3,4 and 6 were characterized by Miyaji, Nakabayashi and Takano. We study this characterization of MNT curves in details. We present explicit algorithms to obtain suitable curve parameters and to construct the corresponding elliptic curves. We also give a heuristic lower bound for the expected number of isogeny classes of MNT curves. Moreover, the related theoretical findings are compared with our experimental results.

Abstract Attribute-Based Encryption (ABE) is a relatively new encryption technology which is similar to multi-receiver encryption but the privacy of ciphertext receivers is protected by a set of attributes such that no one, even the encryptor, knows the identities of the receivers. Although the identities of those receivers remain unknown, the encryptor can ensure that all of the receivers cannot decrypt the ciphertext except for those who match the restrictions on predefined attribute values associated with the ciphertext. However, maintaining the correctness of users¡¦ attributes will take huge cost because the interactions between all users and the key generation center (KGC) are required to renew all of their private keys whenever a user joins, leaves the group, or updates the value of any of his attributes. Since user joining, leaving, and attribute updating may occur frequently in real situations, membership management will become a quite important issue in an ABE system but no existing scheme can perfectly cope with this problem. In this manuscript, we will present an ABE scheme which aims at the issue on dynamic membership management. Our work keeps high flexibility of the constrains on attributes and makes it possible for the procedures of user joining, leaving, and attribute updating to be dynamic, that is, it is not necessary for those users who do not update their attribute statuses to renew their private keys when some user changes his status. Finally, we also formally prove the security of the proposed scheme.

Giant Polyoxometalates : Dynamic Structure and Reactivity. In this thesis different methods were used to study several systems in which giant polyoxometalates are involved. The validity of the theoretical methods applied and the results obtained were always contrasted with the experimental evidence provided by the groups of Prof. Achim Müller (Bielefeld) and Prof. Marcella Bonchio (Padova). In certain cases the theoretical results provided an explanation for experimental observations and in other cases they had allowed prediction as main objective.Chapter IV presents the results regarding encapsulated water molecules inside the giant polyoxometalate cavities. Chapter V presents the results of the studies about ion pairing on polyoxometalates. Chapters VI and VII presents the results of two different polyoxometalates and their catalytic activity. Finally Chapter VIII presents a theoretical study on the effect of counterions on the growth of giant uranium polyperoxometalates. / Polioxometal·lats Gegants: Estructura Dinàmica i Reactivitat.En la present tesi diferents mètodes han estat utilitzats per estudiar diversos sistemes on els polyoxometalats gegants juguen un paper fonamental. La validesa dels mètodes computacionals utilitzats i dels resultats obtinguts han estat sempre contrastats amb les evidencies experimentals facilitades pels grups del Prof. Achim Müller (Bielefeld) i Prof. Marcella Bonchio (Padova). En alguns casos els resultats computacionals han permès explicar les observacions experimentals i en d'altres han permet fer prediccions com a principal objectiu.En el capítol IV es presenten els resultats referents a l'estructura de l'aigua encapsulada en les cavitats presents a polioxometal·lats gegants. El capítol V presenta els resultats dels estudis sobre ion pairing en polioxometal·lats. Els capítols VI i VII presenten els resultats de dos sistemes diferents i la seva activitat com a catalitzadors. Finalment, el capítol VIII presenta un estudi teòric sobre l'efecte dels contraions en el creixement de poliperoxometal·lats gegants d'urani.

The common understanding of proton-neutron pairing, whose fingerprints are currently investigated in N = Z nuclei, relies on Cooper pair mechanism and BCS-type models. In the present thesis we present an alternative approach which, contrary to BCS models, conserves exactly the particle number and the isospin. In this approach the ground state of N=Z nuclei is described as a condensate of alpha-like quartets built by two neutrons and two protons coupled to the total isospin T=0 and total spin J=0. The comparison with exact shell model calculations shows that the quartet condensation model (QCM) gives a very accurate description of pairing correlations in N=Z nuclei, much better than the BCS models. It is also shown that proton-neutron pairing and alpha-type condensation are important not only for N=Z nuclei but also for nuclei with excess neutrons. In the latter case the condensate of alpha-like quartets coexist with the condensate of the neutron pairs in excess relative to the N=Z isotope. Using the framework of QCM we have also studied the competition between the isovector and the isoscalar proton-neutron pairing in nuclei with N=Z. Our results indicate that the contribution of isoscalar pairing to the ground state pairing correlations is very small compared to the isovector pairing.

For pairing-based cryptographic protocols to be both efficient and secure, the underlying genus 2 curves defined over finite fields used must satisfy pairing-friendly conditions, and have small rho-value, which are not likely to be satisfied with random curves. In this thesis, we study two specific families of genus 2 curves defined over finite fields whose Jacobians do not split over the ground fields into a product of elliptic curves, but geometrically split over an extension of the ground field of prescribed degree n=3, 4, or 6. These curves were also studied extensively recently by Kawazoe and Takahashi in 2008, and by Freeman and Satoh in 2009 in their searches of pairing-friendly curves. We present a new method for constructing and identifying suitable curves in these two families which satisfy the pairing-friendly conditions and have rho-values around 4. The computational results of the rho-values obtained in this thesis are consistent with those found by Freeman and Satoh in 2009. An extension of our new method has led to a cryptographic example of a pairing-friendly curve in one of the two families which has rho-value 2.969, and it is the lowest rho-value ever recorded for curves of this type. Our method is different from the method proposed by Freeman and Satoh, since we can prescribe the minimal degree n =3,4 or 6 extension of the ground fields which the Jacobians of the curves split over. / Thesis (Ph.D, Mathematics & Statistics) -- Queen's University, 2011-11-08 18:57:59.988