Accretion and photodesorption of CO ice as a function of the incident angle of deposition

Non-thermal desorption of inter- and circum-stellar ice mantles on dust grains, in particular ultraviolet photon-induced desorption, has gained importance in recent years. These processes may account for the observed gas phase abundances of molecules like CO toward cold interstellar clouds. Ice mantle growth results from gas molecules impinging on the dust from all directions and incidence angles. Nevertheless, the effect of the incident angle for deposition on ice photo-desorption rate has not been studied. This work explores the impact on the accretion and photodesorption rates of the incidence angle of CO gas molecules with the cold surface during deposition of a CO ice layer. Infrared spectroscopy monitored CO ice upon deposition at different angles, ultraviolet-irradiation, and subsequent warm-up. Vacuum-ultraviolet spectroscopy and a Ni-mesh measured the emission of the ultraviolet lamp. Molecules ejected from the ice to the gas during irradiation or warm-up were characterized by a quadrupole mass spectrometer. The photodesorption rate of CO ice deposited at 11 K and different incident angles was rather stable between 0 and 45$^{\circ}$. A maximum in the CO photodesorption rate appeared around 70$^{\circ}$-incidence deposition angle. The same deposition angle leads to the maximum surface area of water ice. Although this study of the surface area could not be performed for CO ice, the similar angle dependence in the photodesorption and the ice surface area suggests that they are closely related. Further evidence for a dependence of CO ice morphology on deposition angle is provided by thermal desorption of CO ice experiments

Interaction Effects on the Magneto-optical Response of Magnetoplasmonic Dimers

The effect that dipole-dipole interactions have on the magneto-optical (MO) properties of magnetoplasmonic dimers is theoretically studied. The specific plasmonic versus magnetoplasmonic nature of the dimer's metallic components and their specific location within the dimer plays a crucial role on the determination of these properties. We find that it is possible to generate an induced MO activity in a purely plasmonic component, even larger than that of the MO one, therefore dominating the overall MO spectral dependence of the system. Adequate stacking of these components may allow obtaining, for specific spectral regions, larger MO activities in systems with reduced amount of MO metal and therefore with lower optical losses. Theoretical results are contrasted and confirmed with experiments for selected structures

Finding positive health in “fortalezas” and “comunidad”: A case study of Latinos/X in Sonoma Valley

Background: Psychological literature and needs-assessment reports emphasize that Latinos/X in Sonoma Valley continue to be impacted by the detrimental effects of the 2017 Northern California wildfires (Domínguez & Yeh, 2018), current immigration enforcement practices, higher rates of poverty, lower educational attainment, persistent barriers to health care access, and obstacles to proportionate leadership representation compared to White American families. To cope with these disparities and navigate life adversities, Sonoma Valley Latinos/X often rely on “fortalezas” [strengths] and community, political, spiritual, cultural, and physical assets. These assets, which often include meaningful interactions with family, friends, neighbors, folk healers, faith-based organizations, and community members, must be incorporated when health care, community, and social service initiatives are designed and implemented. Method: Our community-engaged research team (CERT) used asset-based community development (ABCD) as a conceptual framework (Kretzmann & McKnight, 1993) and community-based participatory research (CBPR) (Wallerstein & Duran, 2003) as a methodological approach to explore the assets and “fortalezas” [strengths] that have enabled Latinos/X to overcome adverse experiences i n Sonoma Valley. Five focus groups and 29 in-depth interviews were conducted because these methods are well-suited for Latino/X relational styles of “platicando” [small talk] (Delgado-Romero, Singh, & De Los Santos, 2018) . Participants were 18 years or older, lived or worked i n Sonoma Valley, and self-identified as Latino/X. Our sample included Latino/X parents, grandparents, artists, folk healers, health and social service providers, community leaders, students, and school personnel. Specific locations where interviews took place include the Hanna Institute, Nuestra Voz, La Luz Center, Center for Well-Being, Boys and Girls Clubs of Sonoma Valley, the Family Resource Center in El Verano, the Sonoma Valley Community Health Center, participants’ houses, and the broader Sonoma Valley community. Our research prioritized depth of relational engagement rather than sample size (Bowden, Caine, Yohani, 2017). We discontinued data collection once our research objectives were achieved and data saturation was accomplished. For data analysis, we used quasi-statistics to quantify the frequency of asset endorsement; open, axial, and selective coding to identify and categorize the assets; and GIS software for the creation of our two asset maps. Findings: Findings indicate that Latinos/X are marginally positioned within Sonoma Valley society. Latinos/X have coped with and adapted to adverse conditions and disparities using and relying on a variety of informal networks and formal sources of support. Their decision to rely on one source of support over another is often based on (a) the extent to which they can afford the services or support required; (b) their particular needs, goals, or objectives at the time the help i s needed; (c) their preference for support resources that honor “respeto” [respect], “personalismo” [a preference for close personal attention i n relationships], and stable and welcoming intimate relationships with others; (d) the accessibility associated with pursuing these support services (e.g., geographic and transportation limitations); and (e) the extent to which culturally relevant and Spanish-speaking support can be found. Dissemination: All data i n this study i s co-owned with the Sonoma Valley community. With the help of our community partners, this report was disseminated in Sonoma Valley during community meetings and forums, offering residents the opportunity to provide feedback, debate preliminary results, and assess whether their voices were captured accurately. Once the community expressed that the findings were representative of the Latino/X experience in Sonoma Valley, we finalized recommendations to assist community members, government officials, and health care and social service providers in designing culturally informed social, health, and/or community programs

General Non-equilibrium Theory of Colloid Dynamics

A non-equilibrium extension of Onsager's canonical theory of thermal fluctuations is employed to derive a self-consistent theory for the description of the statistical properties of the instantaneous local concentration profile n(r,t) of a colloidal liquid in terms of the coupled time evolution equations of its mean value n(r,t) and of the covariance {\sigma}(r,r';t) \equiv of its fluctuations {\delta}n(r, t) = n(r, t) - n(r, t). These two coarse-grained equations involve a local mobility function b(r, t) which, in its turn, is written in terms of the memory function of the two-time correlation function C(r, r' ; t, t') \equiv <{\delta}n(r, t){\delta}n(r',t')>. For given effective interactions between colloidal particles and applied external fields, the resulting self-consistent theory is aimed at describing the evolution of a strongly correlated colloidal liquid from an initial state with arbitrary mean and covariance n^0(r) and {\sigma}^0(r,r') towards its equilibrium state characterized by the equilibrium local concentration profile n^(eq)(r) and equilibrium covariance {\sigma}^(eq)(r,r'). This theory also provides a general theoretical framework to describe irreversible processes associated with dynamic arrest transitions, such as aging, and the effects of spatial heterogeneities

First report of Solanum sisymbriifolium and S. americanum as Natural weed hosts of Tomato chlorosis virus (Genus Crinivirus) in South America.

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The Wigner function associated to the Rogers-Szego polynomials

We show here that besides the well known Hermite polynomials, the q-deformed harmonic oscillator algebra admits another function space associated to a particular family of q-polynomials, namely the Rogers-Szego polynomials. Their main properties are presented, the associated Wigner function is calculated and its properties are discussed. It is shown that the angle probability density obtained from the Wigner function is a well-behaved function defined in the interval [-Pi,Pi), while the action probability only assumes integer values greater or equal than zero. It is emphasized the fact that the width of the angle probability density is governed by the free parameter q characterizing the polynomial.Comment: 12 pages, 2 (mathemathica) figure

Entropy and equilibrium state of free market models

Many recent models of trade dynamics use the simple idea of wealth exchanges among economic agents in order to obtain a stable or equilibrium distribution of wealth among the agents. In particular, a plain analogy compares the wealth in a society with the energy in a physical system, and the trade between agents to the energy exchange between molecules during collisions. In physical systems, the energy exchange among molecules leads to a state of equipartition of the energy and to an equilibrium situation where the entropy is a maximum. On the other hand, in the majority of exchange models, the system converges to a very unequal condensed state, where one or a few agents concentrate all the wealth of the society while the wide majority of agents shares zero or almost zero fraction of the wealth. So, in those economic systems a minimum entropy state is attained. We propose here an analytical model where we investigate the effects of a particular class of economic exchanges that minimize the entropy. By solving the model we discuss the conditions that can drive the system to a state of minimum entropy, as well as the mechanisms to recover a kind of equipartition of wealth