Alien Registration- Gaudreau, Mary J. (Westbrook, Cumberland County)

https://digitalmaine.com/alien_docs/20048/thumbnail.jp

Virtual knot groups and almost classical knots

We define a group-valued invariant of virtual knots and relate it to various other group-valued invariants of virtual knots, including the extended group of Silver-Williams and the quandle group of Manturov and Bardakov-Bellingeri. A virtual knot is called almost classical if it admits a diagram with an Alexander numbering, and in that case we show that the group factors as a free product of the usual knot group and Z. We establish a similar formula for mod p almost classical knots, and we use these results to derive obstructions to a virtual knot K being mod p almost classical. Viewed as knots in thickened surfaces, almost classical knots correspond to those that are homologically trivial. We show they admit Seifert surfaces and relate their Alexander invariants to the homology of the associated infinite cyclic cover. We prove the first Alexander ideal is principal, recovering a result first proved by Nakamura et al. using different methods. The resulting Alexander polynomial is shown to satisfy a skein relation, and its degree gives a lower bound for the Seifert genus. We tabulate almost classical knots up to 6 crossings and determine their Alexander polynomials and virtual genus.Comment: 44 page

A short empirical note on perfectionism and flourishing

Flourishing describes an optimal state of mental health characterized by emotional, psychological, and social well-being. In a recent publication, Flett and Hewitt (2015) suggested that perfectionism prevents people from flourishing. Perfectionism, however, is a multidimensional personality characteristic, and its various dimensions show different relationships with indicators of subjective well-being. In the first empirical study of perfectionism and flourishing, we examined the relationships of multidimensional perfectionism (self-oriented, other-oriented, and socially prescribed perfectionism) and self-reported flourishing in the past two weeks. Results from the sample of 388 university students revealed that only socially prescribed perfectionism showed a negative relationship with flourishing, whereas self-oriented perfectionism showed a positive relationship. These results were unchanged when positive and negative affect were controlled statistically. Our findings indicate that not all dimensions of perfectionism undermine flourishing and that it is important to differentiate perfectionistic strivings and concerns when regarding the perfectionism–flourishing relationship

Coherent Transport Through a Quadruple Point in a Few Electron Triple Dot

A few electron double electrostatic lateral quantum dot can be transformed into a few electron triple quantum dot by applying a different combination of gate voltages. Quadruple points have been achieved at which all three dots are simultaneously on resonance. At these special points in the stability diagram four occupation configurations are possible. Both charge detection and transport experiments have been performed on this device. In this short paper we present data and confirm that transport is coherent by observing a Pi phase shift in magneto-conductance oscillations as one passes through the quadruple point.Comment: To be published in ICPS Conf. Proceedings 200

New onset, transient and stable motoric cognitive risk syndrome: Clinical characteristics and association with incidence of probable dementia in the NuAge cohort.

BACKGROUND: Motoric cognitive risk syndrome (MCR) is a pre-dementia stage. The existence of stable and transient MCR, their related clinical characteristics and their association with incident dementia is a matter of debate. OBJECTIVE: This study aims to examine the clinical characteristics and the time course associated with new onset, transient and stable MCR, and their association with incidence of probable dementia in community-dwelling older adults living in the province of Quebec (Canada). DESIGN: Quebec elderly population-based observational cohort study with 3 years of follow-up. SETTING: Community dwellers. SUBJECTS: A subset of participants (n = 1,113) from the “Quebec Longitudinal Study on Nutrition and Successful Aging” (NuAge) cohort. METHODS: Participants with MCR were identified at baseline and after 1 year of follow-up. Socio-demographic characteristics, 30-item Geriatric depression scale (GDS) score, cardiovascular risk factors and diseases were recorded at baseline. Incidence of probable dementia was measured at annual follow-up visits over a 3-year period. RESULTS: Over the period of the first year of follow-up, the prevalence of MCR was 8.5% with 4.3% having new onset MCR, 2.8% transient MCR and 1.4% stable MCR. A higher 30-item GDS score was reported with new onset and transient MCR, and the highest prevalence of cerebrovascular diseases was shown with stable MCR compared to non-MCR participants (p < 0.05). MCR was associated with overall incidence of probable dementia, regardless of its status (Hazard Ratio ≥ 1.86, p ≤ 0.034). CONCLUSION: Greater prevalence of depressive symptoms and cerebrovascular diseases were reported, respectively, with new onset and transient MCR, and stable MCR. The association of MCR with incidence of probable dementia remains significant, regardless of MCR subtypes

The origin of switching noise in GaAs/AlGaAs lateral gated devices

We have studied the origin of switching (telegraph) noise at low temperature in lateral quantum structures defined electrostatically in GaAs/AlGaAs heterostructures by surface gates. The noise was measured by monitoring the conductance fluctuations around $e^2/h$ on the first step of a quantum point contact at around 1.2 K. Cooling with a positive bias on the gates dramatically reduces this noise, while an asymmetric bias exacerbates it. We propose a model in which the noise originates from a leakage current of electrons that tunnel through the Schottky barrier under the gate into the doped layer. The key to reducing noise is to keep this barrier opaque under experimental conditions. Bias cooling reduces the density of ionized donors, which builds in an effective negative gate voltage. A smaller negative bias is therefore needed to reach the desired operating point. This suppresses tunnelling from the gate and hence the noise. The reduction in the density of ionized donors also strengthens the barrier to tunneling at a given applied voltage. Support for the model comes from our direct observation of the leakage current into a closed quantum dot, around $10^{-20} \mathrm{A}$ for this device. The current was detected by a neighboring quantum point contact, which showed monotonic steps in time associated with the tunneling of single electrons into the dot. If asymmetric gate voltages are applied, our model suggests that the noise will increase as a consequence of the more negative gate voltage applied to one of the gates to maintain the same device conductance. We observe exactly this behaviour in our experiments.Comment: 8 pages, 7 figure

Theory of electronic transport through a triple quantum dot in the presence of magnetic field

Theory of electronic transport through a triangular triple quantum dot subject to a perpendicular magnetic field is developed using a tight binding model. We show that magnetic field allows to engineer degeneracies in the triple quantum dot energy spectrum. The degeneracies lead to zero electronic transmission and sharp dips in the current whenever a pair of degenerate states lies between the chemical potential of the two leads. These dips can occur with a periodicity of one flux quantum if only two levels contribute to the current or with half flux quantum if the three levels of the triple dot contribute. The effect of strong bias voltage and different lead-to-dot connections on Aharonov-Bohm oscillations in the conductance is also discussed

An electrostatically defined serial triple quantum dot charged with few electrons

A serial triple quantum dot (TQD) electrostatically defined in a GaAs/AlGaAs heterostructure is characterized by using a nearby quantum point contact as charge detector. Ground state stability diagrams demonstrate control in the regime of few electrons charging the TQD. An electrostatic model is developed to determine the ground state charge configurations of the TQD. Numerical calculations are compared with experimental results. In addition, the tunneling conductance through all three quantum dots in series is studied. Quantum cellular automata processes are identified, which are where charge reconfiguration between two dots occurs in response to the addition of an electron in the third dot.Comment: 12 pages, 9 figure