Alternating groups and moduli space lifting Invariants

Main Theorem: Spaces of r-branch point 3-cycle covers, degree n or Galois of degree n!/2 have one (resp. two) component(s) if r=n-1 (resp. r\ge n). Improves Fried-Serre on deciding when sphere covers with odd-order branching lift to unramified Spin covers. We produce Hurwitz-Torelli automorphic functions on Hurwitz spaces, and draw Inverse Galois conclusions. Example: Absolute spaces of 3-cycle covers with +1 (resp. -1) lift invariant carry canonical even (resp. odd) theta functions when r is even (resp. odd). For inner spaces the result is independent of r. Another use appears in, http://www.math.uci.edu/~mfried/paplist-mt/twoorbit.html, "Connectedness of families of sphere covers of A_n-Type." This shows the M(odular) T(ower)s for the prime p=2 lying over Hurwitz spaces first studied by, http://www.math.uci.edu/~mfried/othlist-cov/hurwitzLiu-Oss.pdf, Liu and Osserman have 2-cusps. That is sufficient to establish the Main Conjecture: (*) High tower levels are general-type varieties and have no rational points.For infinitely many of those MTs, the tree of cusps contains a subtree -- a spire -- isomorphic to the tree of cusps on a modular curve tower. This makes plausible a version of Serre's O(pen) I(mage) T(heorem) on such MTs. Establishing these modular curve-like properties opens, to MTs, modular curve-like thinking where modular curves have never gone before. A fuller html description of this paper is at http://www.math.uci.edu/~mfried/paplist-cov/hf-can0611591.html .Comment: To appear in the Israel Journal as of 1/5/09; v4 is corrected from proof sheets, but does include some proof simplification in \S

Superwind-driven Intense H2_2 Emission in NGC 6240 II: Detailed Comparison of Kinematical and Morphological Structures of the Warm and Cold Molecular Gas

We report on our new analysis of the spatial and kinematical distribution of warm and cold molecular gas in NGC 6240, which was undertaken to explore the origin of its unusually luminous H$_2$ emission. By comparing three-dimensional emission-line data (in space and velocity) of CO (J=2-1) in the radio and H$_2$ in the near infrared, we are able to study the H$_2$ emitting efficiency, defined in terms of the intensity ratio of H$_2$ to CO [$I$(H$_2$)/$I$(CO)], as a function of velocity. The integrated H$_2$ emitting efficiency is calculated by integrating the velocity profile of H$_2$ emitting efficiency in blue, red, and total (blue + red) velocity regions of the profile. We find that (1) both the total H$_2$ emitting efficiency and the blue-to-red ratio of the efficiency are larger in regions surrounding the CO and H$_2$ intensity peaks, and (2) the H$_2$ emitting efficiency and the kinematical conditions in the warm molecular gas are closely related to each other. A collision between the molecular gas concentration and the external superwind outflow from the southern nucleus seems plausible to explain these characteristics, since it can reproduce the enhanced emitting efficiency of blueshifted H$_2$ around the molecular gas concentration, if we assume that the superwind blows from the southern nucleus toward us, hitting the entire gas concentration from behind. In this model, internal cloud-cloud collisions within the molecular gas concentration are enhanced by the interaction with the superwind outflow, and efficient and intense shock-excited H$_2$ emission is expected as a result of the cloud-crushing mechanism.Comment: 12 pages, 6 figures, accepted for publication in A

Cumulative effect of Weibel-type instabilities in counterstreaming plasmas with non-Maxwellian anisotropies

Counterstreaming plasma structures are widely present in laboratory experiments and astrophysical systems, and they are investigated either to prevent unstable modes arising in beam-plasma experiments or to prove the existence of large scale magnetic fields in astrophysical objects. Filamentation instability arises in a counterstreaming plasma and is responsible for the magnetization of the plasma. Filamentationally unstable mode is described by assuming that each of the counterstreaming plasmas has an isotropic Lorentzian (kappa) distribution. In this case, the filamentation instability growth rate can reach a maximum value markedly larger than that for a a plasma with a Maxwellian distribution function. This behaviour is opposite to what was observed for the Weibel instability growth rate in a bi-kappa plasma, which is always smaller than that obtained for a bi-Maxwellian plasma. The approach is further generalized for a counterstreaming plasma with a bi-kappa temperature anisotropy. In this case, the filamentation instability growth rate is enhanced by the Weibel effect when the plasma is hotter in the streaming direction, and the growth rate becomes even larger. These effects improve significantly the efficiency of the magnetic field generation, and provide further support for the potential role of the Weibel-type instabilities in the fast magnetization scenarios

Robust Forecasting of Non-Stationary Time Series

This paper proposes a robust forecasting method for non-stationary time series. The time series is modelled using non-parametric heteroscedastic regression, and fitted by a localized MM-estimator, combining high robustness and large efficiency. The proposed method is shown to produce reliable forecasts in the presence of outliers, non-linearity, and heteroscedasticity. In the absence of outliers, the forecasts are only slightly less precise than those based on a localized Least Squares estimator. An additional advantage of the MM-estimator is that it provides a robust estimate of the local variability of the time series.Heteroscedasticity;Non-parametric regression;Prediction;Outliers;Robustness

About the morphology of dwarf spheroidal galaxies and their dark matter content

The morphological properties of the Carina, Sculptor and Fornax dwarfs are investigated using new wide field data with a total area of 29 square degrees. The stellar density maps are derived, hinting that Sculptor possesses tidal tails indicating interaction with the Milky Way. Contrary to previous studies we cannot find any sign of breaks in the density profiles for the Carina and Fornax dwarfs. The possible existence of tidal tails in Sculptor and of King limiting radii in Fornax and Carina are used to derive global M/L ratios, without using kinematic data. By matching those M/L ratios to kinematically derived values we are able to constrain the orbital parameters of the three dwarfs. Fornax cannot have M/L smaller than 3 and must be close to its perigalacticon now. The other extreme is Sculptor that needs to be on an orbit with an eccentricity bigger than 0.5 to be able to form tidal tails despite its kinematic M/L.Comment: 9 pages, 7 figures, accepted by A&

Calmly Coping: A Motivational Interviewing via Co-Active Life Coaching (MI-via-CALC) Intervention For University Students Suffering From Stress

The purpose of this semester-long pilot study was to assess the impact of Motivational Interviewing via Co-Active Life Coaching (MI-via-CALC) on the stress management experiences of 30 full-time, English-speaking students aged 17-24 years. Participants’ experiences were assessed quantitatively using the previously validated Perceived Stress Scale and Hospital Anxiety and Depression Scale (which is divided into Anxiety and Depression scales) at pre-, mid-, and post-intervention. Three one-way, repeated-measures ANOVAs were completed for each scale and statistically significant differences in stress reduction were found for all scales between pre-intervention to mid-intervention, and between pre-intervention to post- intervention; no statistically significant differences occurred between mid-intervention to post- intervention. Inductive content analysis of the qualitative interviews at pre-, mid-, and post- intervention revealed participants’ positive experiences with the intervention. Methods were employed throughout to enhance qualitative data trustworthiness. MI-via-CALC is a promising approach for university students struggling with stress and additional research on a larger sample is warranted

Breaking Under/Grad - Assessing and Addressing Stress, Anxiety, and Resiliency Among Undergraduate and Graduate Students via Motivational Interviewing and A Smart, Healthy Campus Intervention

The purpose of this dissertation was to assess mental health among students, as well as innovative interventions designed to provide tools to cope with the mental health challenges of stress and anxiety while building resiliency. Three distinct, yet related, studies were conducted. Study I: This academic-year-long pilot study explored senior students’ (‘mentors’; N= 30) experiences interacting with first-years to build resilience via physical activity (PA) and mentorship. Mentors’ psychosocial experiences were tracked via qualitative interviews and validated questionnaires at pre-, mid-, and immediate post-intervention. Inductive content analysis revealed the program’s positive influence on PA, resilience, and mental health; and some added stressors. One-way, repeated-measures ANOVAs indicated few statistically significant findings regarding participants’ levels of resilience, behavioural control, and positive affect. Study II: This mixed methods pilot study investigated graduate students’ (n = 11) experiences in an 8-month peer coaching program. Participants’ psychosocial experiences were assessed via individual semi-structured interviews and validated questionnaires (BRS, MHI, SF-36) at pre-, mid-, and immediate post-intervention. Inductive content analysis revealed peer coaching as having positively impacted participants’ ability to cope with stress and anxiety, and enhanced resilience. One-way, repeated-measures ANOVAs indicated no statistical significance for any of the questionnaires/surveys. Study III:Through the distribution of three campus-wide surveys/questionnaires (i.e. BRS, n= 598; MHI, n= 619; SF-36, n= 696),information was gathered about the current state of mental health and wellness, and resiliency among undergraduate (UGS) and graduate students(GS). Focus groups were conducted to enhance and put in context the quantitative information. Both UGS and GS indicated more services are needed to address mental health, with a need for more counsellors. PA positively affected mental health and resilience for both groups. The need for easier/increased access to PA was voiced. The findings from these studies have demonstrated that while GS experience some different stressors than UGS, and that they would prefer to access mental health-related services in an environment separate from UGS, both groups: (a) struggle with stress and anxiety; (b) voiced the need for more counsellors; and (c) described PA and peer-coaching/mentorship as benefitting their mental health and resilience

The formation of ion acoustic shocks

Recent experiments performed in the double plasma (DP) device have verified the existence of electrostatic ion acoustic laminar shocks. The influence of the piston on the shock structure is investigated by modeling the DP device and by numerically solving the temporal and spatial evolution of the shock. In order to isolate piston effects, as opposed to kinetic theory effects such as reflected ions and trapped electrons, the DP plasma is modeled as a cold ion fluid with isothermal Boltzmann electrons. It is shown that laminar shock transitions with structure agreeing with DP shock experiments can be excited