5,269 research outputs found
2-Selmer Parity for Hyperelliptic Curves in Quadratic Extensions
We study the 2-parity conjecture for Jacobians of hyperelliptic curves over
number fields. Under some mild assumptions on their reduction, we prove it over
quadratic extensions of the base field, providing essentially the first
examples of the 2-parity conjecture in dimension greater than one. The proof
proceeds via a generalisation of a formula of Kramer and Tunnell relating local
invariants of the curve, which may be of independent interest. Particularly
surprising is the appearance in the formula of terms that govern whether or not
the Cassels-Tate pairing on the Jacobian is alternating, which first appeared
in a paper of Poonen and Stoll. We prove this local formula in many instances
and show that in all cases it follows from standard global conjectures.Comment: 47 pages, 3 figure
Tate module and bad reduction
Let C/K be a curve over a local field. We study the natural semilinear action
of Galois on the minimal regular model of C over a field F where it becomes
semistable. This allows us to describe the Galois action on the l-adic Tate
module of the Jacobian of C/K in terms of the special fibre of this model over
F.Comment: 13 pages, final version, to appear in Proc. AM
EMPIRICALLY ANALYZING THE “FIVE PERCENT RULE OF MATERIALITY” IN FINANCIAL REPORTING DECISIONS
This study analyzes a sample of financial restatements from 2011 and 2012 as a way to assess a proposed “five percent rule of materiality” for financial reporting decisions. Such a rule claims the average investor is only influenced by income restatements greater than five percent. Market reactions are observed through stock price, volume, and bid-ask spread following the restatement in the Form 10-K/A. The study finds only some firms restating net income by more than five percent experience statistically significant reactions in two of these metrics. The study also suggests percent change in net income is a significant driver of percent change in the three metrics via a regression analysis
Design and testing of a position adaptation system for KUKA robots using photoelectric sensors
This thesis presents the development and analysis of a position monitoring and adaptation system to be used in conjunction with a KUKA KR16-2 articulated robot using components readily available in most manufacturing settings. This system could be beneficial in the manufacturing sector in areas such as polymer welding and spray painting. In the former it could be used to maintain an effective distance between a welding end effector laying molten plastic and the surface area of the parts being welded, or in the case of the latter the system would be useful in painting objects of unknown shape or objects with unknown variations in the surface level. In the case of spray painting if you spray to close to an object you will get an inconsistent amount of paint applied to an area. This system would maintain the programmed distance between the robot system and target object. Typically, systems that achieve this level of control rely on expensive sensors such as force torque sensors. This research proposes to take the first step in trying to address the technical problems by introducing a novel way of adapting to a target surface deformation using comparably low cost photoelectric diffuse sensors. The key outcomes of this thesis can be found in the form of a software package to interface the photo-electric sensors to the KUKA robot system. This system is operated by a custom-built algorithm which is capable of dynamically calculating robot movements based off the sensor input. Additionally, an optimum system setup is developed with different configurations of sensor mounting and speeds of robot operation discussed and tested. The viability of the photo-electric diffuses sensors used in this application is also considered with further works suggested. Finally, a secondary application is developed for recording and analysing KUKA robot movements for use in other research activities
SAHAJA YOGA: AN ANCIENT PATH TO MODERN MENTAL HEALTH?
The present study looks to evaluate the effectiveness of the meditative practice of Sahaja
Yoga as a treatment for the symptoms of anxiety and depression. Whilst there is a small
research literature that has investigated the efficacy of meditation (usually based upon
the Buddhist Vipassana tradition) for the treatment of such symptoms, and a smaller
literature looking at the effectiveness of Sahaja Yoga in the treatment of a number of
physical health problems, no published studies have looked at the effectiveness of Sahaja
Yoga as a treatment for mental health problems.
The present study therefore compared three independent groups, these being a 'waiting
list' control group, a cognitive-behavioural (CBT) based stress management group and a
Sahaja Yoga meditation group. Both treatment groups consisted of six, two hourly
sessions, once per week, with symptom severity being measured at pre- and post-treatment
using the Hospital Anxiety and Depression scale (HADs) and the 12 item
General Health Questionnaire (GHQ-12).
Data were analysed using MANOV A and repeated measures AN OVA tests. The results
show that, compared to controls, the participants in the Sahaja Yoga group reported
significant reductions on all measures of symptomology, however, surprisingly, the CBT
based group showed no such reductions. Limitations of the study, barriers to the use of
Sahaja Yoga in clinical practice and the need for future research, particularly regarding
process, are considered.Exeter County Council, Social Services Dept
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