Dark matter, singlet extensions of the nuMSM, and symmetries

We consider an extension of the nuMSM in which sterile neutrino masses originate from the VEV of a Higgs singlet phi and dark matter is produced through the decays of phi rather than through active-sterile neutrino mixing. This model, which we refer to as the nuNMSM, can readily satisfy or escape the constraints on warm dark matter from the Lyman-alpha forest and other small scale structure. However, it requires a particular hierarchy of Majorana masses and Yukawa couplings without an obvious origin. We show that the hierarchical parameters of the nuNMSM can arise from symmetries broken at or near the Planck scale for two specific examples of this model: one in which phi helps stabilize the electroweak vacuum through a scalar threshold effect and one in which phi is a light inflaton. Both examples require a complex phi and have several experimental signatures that are distinct from the nuMSM. These signatures include additional dark radiation that is relativistic at both primordial nucleosynthesis and CMB decoupling and, for the former, a large invisible branching ratio of the Higgs.Comment: 22 pages, 3 tables. v2: Discussion clarified and references added. Matches published versio

Ultra-weak sector, Higgs boson mass, and the dilaton

The Higgs boson mass may arise from a portal coupling to a singlet field $\sigma$ which has a very large VEV $f \gg m_\text{Higgs}$. This requires a sector of "ultra-weak" couplings $\zeta_i$, where $\zeta_i \lesssim m_\text{Higgs}^2 / f^2$. Ultra-weak couplings are technically naturally small due to a custodial shift symmetry of $\sigma$ in the $\zeta_i \rightarrow 0$ limit. The singlet field $\sigma$ has properties similar to a pseudo-dilaton. We engineer explicit breaking of scale invariance in the ultra-weak sector via a Coleman-Weinberg potential, which requires hierarchies amongst the ultra-weak couplings.Comment: 6 page

An ultra-weak sector, the strong CP problem and the pseudo-Goldstone dilaton

In the context of a Coleman-Weinberg mechanism for the Higgs boson mass, we address the strong CP problem. We show that a DFSZ-like invisible axion model with a gauge-singlet complex scalar field S, whose couplings to the Standard Model are naturally ultra-weak, can solve the strong CP problem and simultaneously generate acceptable electroweak symmetry breaking. The ultra-weak couplings of the singlet S are associated with underlying approximate shift symmetries that act as custodial symmetries and maintain technical naturalness. The model also contains a very light pseudo-Goldstone dilaton that is consistent with cosmological Polonyi bounds, and the axion can be the dark matter of the universe. We further outline how a SUSY version of this model, which may be required in the context of Grand Unification, can avoid introducing a hierarchy problem.Comment: 9 page

Observations and models for needle-tissue interactions

The asymmetry of a bevel-tip needle results in the needle naturally bending when it is inserted into soft tissue. In this study we present a mechanics-based model that calculates the deflection of the needle embedded in an elastic medium. Microscopic observations for several needle- gel interactions were used to characterize the interactions at the bevel tip and along the needle shaft. The model design was guided by microscopic observations of several needle- gel interactions. The energy-based model formulation incor- porates tissue-specific parameters such as rupture toughness, nonlinear material elasticity, and interaction stiffness, and needle geometric and material properties. Simulation results follow similar trends (deflection and radius of curvature) to those observed in macroscopic experimental studies of a robot- driven needle interacting with different kinds of gels. These results contribute to a mechanics-based model of robotic needle steering, extending previous work on kinematic models

Increased Perceived Stress is Associated with Blunted Hedonic Capacity: Potential Implications for Depression Research

Preclinical studies suggest that stress exerts depressogenic effects by impairing hedonic capacity, in humans, however, the precise mechanisms linking stress and depression are largely unknown. As an initial step towards better understanding the association between stress and anhedonia, the present study tested, in two independent samples, whether individuals reporting elevated stress exhibit decreased hedonic capacity. The Perceived Stress Scale (PSS) measured the decree to which participants appraised their daily life as unpredictable, uncontrollable, and overwhelming. Hedonic capacity was objectively assessed using a signal-detection task based on a differential reinforcement schedule. Decreased reward responsiveness (i.e., the participants propensity to modulate behavior as a function of reward) was used as an operational measure of hedonic capacity. In both Study 1 (n = 88) and Study 2 (n = 80), participants with high PSS scores displayed blunted reward responsiveness and reported elevated anhedonic symptoms. Additionally, PSS scores predicted reduced reward responsiveness even after controlling for general distress and anxiety symptoms. These findings are consistent with preclinical data highlighting links between stress and anhedonia, and offer promising insights into potential mechanisms linking stress to depression.Psycholog

Increased Perceived Stress is Associated with Blunted Hedonic Capacity: Potential Implications for Depression Research

Preclinical studies suggest that stress exerts depressogenic effects by impairing hedonic capacity, in humans, however, the precise mechanisms linking stress and depression are largely unknown. As an initial step towards better understanding the association between stress and anhedonia, the present study tested, in two independent samples, whether individuals reporting elevated stress exhibit decreased hedonic capacity. The Perceived Stress Scale (PSS) measured the decree to which participants appraised their daily life as unpredictable, uncontrollable, and overwhelming. Hedonic capacity was objectively assessed using a signal-detection task based on a differential reinforcement schedule. Decreased reward responsiveness (i.e., the participants propensity to modulate behavior as a function of reward) was used as an operational measure of hedonic capacity. In both Study 1 (n = 88) and Study 2 (n = 80), participants with high PSS scores displayed blunted reward responsiveness and reported elevated anhedonic symptoms. Additionally, PSS scores predicted reduced reward responsiveness even after controlling for general distress and anxiety symptoms. These findings are consistent with preclinical data highlighting links between stress and anhedonia, and offer promising insights into potential mechanisms linking stress to depression.Psycholog

Recruitment Facilitation and Spatial Pattern Formation in Soft-Bottom Mussel Beds

Mussels (Mytilus edulis) build massive, spatially complex, biogenic structures that alter the biotic and abiotic environment and provide a variety of ecosystem services. Unlike rocky shores, where mussels can attach to the primary substrate, soft sediments are unsuitable for mussel attachment. We used a simple lattice model, field sampling, and field and laboratory experiments to examine facilitation of recruitment (i.e., preferential larval, juvenile, and adult attachment to mussel biogenic structure) and its role in the development of power-law spatial patterns observed in Maine, USA, soft-bottom mussel beds. The model demonstrated that recruitment facilitation produces power-law spatial structure similar to that in natural beds. Field results provided strong evidence for facilitation of recruitment to other mussels—they do not simply map onto a hard-substrate template of gravel and shell hash. Mussels were spatially decoupled from non-mussel hard substrates to which they can potentially recruit. Recent larval recruits were positively correlated with adult mussels, but not with other hard substrates. Mussels made byssal thread attachments to other mussels in much higher proportions than to other hard substrates. In a field experiment, mussel recruitment was highest to live mussels, followed by mussel shell hash and gravel, with almost no recruitment to muddy sand. In a laboratory experiment, evenly dispersed mussels rapidly self-organized into power-law clusters similar to those observed in nature. Collectively, the results indicate that facilitation of recruitment to existing mussels plays a major role in soft-bottom spatial pattern development. The interaction between large-scale resource availability (hard substrate) and local-scale recruitment facilitation may be responsible for creating complex power-law spatial structure in soft-bottom mussel beds

Evaluating outcomes from an integrated health service for older patients

Background: Hospital-associated disability is the loss of the ability to complete one activity of daily living (ADL), with this decline occurring between the onset of acute illness and discharge from the hospital. Approximately 30% of patients who are >70 years old and admitted to hospitals are discharged with an ADL disability. Comprehensive geriatric assessment (CGA) models use a multidimensional, interdisciplinary process of diagnosis and treatment with the goal of improving outcomes and decreasing lengths of stay. Methods: A retrospective clinical audit of Ipswich Hospital’s medical records included patients for random selection who were >75 years of age and had an acute admission to the Older Person Evaluation Review and Assessment (OPERA) or general medicine (GM) service from July 2012 to December 2012. Data were collected for the entire admission period on length of stay, comorbidities, allied health visits, functional ability, and delirium and dementia at admission. Results: Of the 267 patients evaluated, 133 were admitted to the OPERA service, and 134 were admitted to the GM service. Patients admitted to the OPERA service were significantly more ill than patients admitted to the GM service as measured by the Charlson Comorbidity Index scores (6.53 - 1.83 vs 6.02 - 1.96, respectively, P¼0.02), Katz Index of Independence in ADL scores (3.77 - 2.22 vs 4.72 - 2.00, respectively,

What is "gender expression"? How a New and Nebulous Human Rights Construct Is Taking Shape in Ontario School Board Policy Documents

In 2002, jurisdictions across Canada began adding two new protected grounds to their human rights laws: gender identity and/or gender expression. Gender identity protections generally apply only to transgender people, whereas gender expression protections may apply to all Canadians in places like K–12 schools. However, it remains legally unclear what kind of action, utterance, or pattern constitutes gender expression discrimination, and who can access related protections. In search of clarification, this article explores how the meaning of gender expression is being constructed within policy documents (N = 206) authored at the level of Ontario’s English public secular school boards. Keywords: gender expression, gender identity, transgender, education policy, education law, K–12, Ontario, CanadaEn 2002, des ressorts dans l’ensemble du Canada ont commencé à ajouter deux nouveaux motifs de discrimination interdits à leurs lois sur les droits de la personne, soit l’identité sexuelle et/ou l’expression de l’identité sexuelle ou de genre. Les protections entourant l’identité ne s’appliquent en général qu’aux personnes transgenres, alors que les protections entourant l’expression sexuelle ou de genre peuvent s’appliquer à tous les Canadiens et Canadiennes dans des endroits tels que les écoles élémentaires et secondaires. Une incertitude juridique demeure toutefois à l’égard du type d’action, de propos ou de schéma de comportement qui constitue une discrimination à l’égard de l’expression sexuelle ou de genre et à savoir qui peut se prévaloir des protections qui en découlent. Dans le but de clarifier cet aspect, cet article explore la manière dont la signification de l’expression sexuelle ou de genre est façonnée dans le cadre des politiques (N = 206) adoptées à l’échelon des conseils scolaires publics laïques de l’Ontario. Mots-clés : l’expression de l’identité sexuelle, l’identité sexuelle, transgenre, politique d’éducation, droit de l’éducation, écoles élémentaires et secondaires, Ontario, Canad

Technology and Opportunity: People with Serious Mental Illness and Social Connection

Objective: Little information exists regarding how individuals with serious mental illness use technology and whether this usage facilitates social connections. This study contributes to filling this knowledge gap by examining ways in which a sample of persons with serious mental illness use cell phones and the Internet. Methods: Interviews with 50 consumers living in supported housing were asked about their use of cell phones and computers and their perceptions of social connections. Results: Cell phones and computers allowed greater linkage with social, medical, mental health, and employment resources. Nearly all obtained phones through publicly funded programs. “Running out of minutes” was common and associated with disrupted communication and safety concerns. Few people owned computers, resulting in restricted access. Conclusion: Policymakers should consider providing free or discounted hardware, subsidizing unlimited plans, and promoting computer literacy