Principles from history, community psychology and developmental psychology applied to community based programs for deinstitutionalized youth

This article analyses the issues of the deinstitutionalization of youth, and the development of community based services, using some historical data and some of the principles of community psychology. The basic premise is that there is no such thing as a social vacuum. All programs are implemented and function in an elaborate social context

Regulatory activity revealed by dynamic correlations in gene expression noise

Gene regulatory interactions are context dependent, active in some cellular states but not in others. Stochastic fluctuations, or 'noise', in gene expression propagate through active, but not inactive, regulatory links^(1,2). Thus, correlations in gene expression noise could provide a noninvasive means to probe the activity states of regulatory links. However, global, 'extrinsic', noise sources generate correlations even without direct regulatory links. Here we show that single-cell time-lapse microscopy, by revealing time lags due to regulation, can discriminate between active regulatory connections and extrinsic noise. We demonstrate this principle mathematically, using stochastic modeling, and experimentally, using simple synthetic gene circuits. We then use this approach to analyze dynamic noise correlations in the galactose metabolism genes of Escherichia coli. We find that the CRP-GalS-GalE feed-forward loop is inactive in standard conditions but can become active in a GalR mutant. These results show how noise can help analyze the context dependence of regulatory interactions in endogenous gene circuits

Principles from history, community psychology and developmental psychology applied to community based programs for deinstitutionalized youth

ABSTRACT: This article analyses the issues of the deinstitutionalization of youth, and the development of community based services, using some historical data and some of the principles of community psychology. The basic premise is that there is no such thing as a social vacuum. All programs are implemented and function in an elaborate social context.RESUMO: Este artigo analisa as questões referentes à desinstitunalização dos jovens e ao desenvolvimento de serviços na comunidade, fazendo uso de alguns dados históricos e de alguns dos princípios da psicologia comunitária. A premissa de base é de que não existe o vácuo social. Todos os programas são implementados e funcionam num elaborado contexto social.info:eu-repo/semantics/publishedVersio

Instabilities and Oscillations in Isotropic Active Gels

We present a generic formulation of the continuum elasticity of an isotropic crosslinked active gel. The gel is described by a two-component model consisting of an elastic network coupled frictionally to a permeating fluid. Activity is induced by active crosslinkers that undergo an ATP-activated cycle and transmit forces to the network. The on/off dynamics of the active crosslinkers is described via rate equations for unbound and bound motors. For large activity motors yield a contractile instability of the network. At smaller values of activity, the on/off motor dynamics provides an effective inertial drag on the network that opposes elastic restoring forces, resulting in spontaneous oscillations. Our work provides a continuum formulation that unifies earlier microscopic models of oscillations in muscle sarcomeres and a generic framework for the description of the large scale properties of isotropic active solids.Comment: 13 pages, 5 figure

A Modification of the Garrett–Munk Internal Wave Spectrum

The Garrett–Munk (GM) spectrum continues to be a useful description of the oceanic internal wave field. However, there are several inconsistencies and ambiguities that make it difficult to use in comparing internal wave fields at different latitudes, stratifications, and water depths. A modified spectral formulation is presented that treats three problems with the Garrett–Munk formulation: the normalization of the energy spectrum as a function of frequency bandwidth, the energy distribution at frequencies below the semidiurnal tide, and the treatment of vertical boundaries and turning points. Addressing these problems leads to a substitution of the GM parameters E (nondimensional energy), b (vertical length scale), and N₀ (buoyancy frequency scale) with two new dimensional scales: E[subscript]ref, the energy per unit mass, and D(ω), the Wentzel–Kramers–Brillouin (WKB)-scaled thickness of the vertical waveguide. The advantages of the modified spectrum are illustrated by comparing with observations from the equator and the continental shelf

Internal waves under the Arctic pack ice during the Arctic Internal Wave Experiment: The coherence structure

The spectral composition of internal gravity waves under the Arctic pack ice during the Arctic Internal Wave Experiment (AIWEX) was found to be strikingly different from observations at lower latitudes. Time series of vertical displacement were inferred from horizontal and vertical arrays of temperature and conductivity sensors. Frequency spectra indicate a whiter spectrum (spectral slope near −1) and a less energetic wave field (by a factor of 0.02) than observations at lower latitude. The analysis of vertical and horizontal coherences revealed a horizontally isotropic wave field that is consistent with assumptions of a random field of linear internal waves. The wavenumber bandwidth of the wave field is about a factor of 10 wider than found at lower latitude

The upper ocean internal wave field: Influence of the surface and mixed layer

A model is developed to calculate the upper ocean internal wave spectrum as modified by the surface boundary and mixed layer. The Garrett‐Munk spectrum is assumed to describe the deep ocean wave field. The main effect of the surface and mixed layer is to align the vertical structure of the waves forming vertically standing waves locally; this contrasts with the assumption of random alignment in the Garrett‐Munk model. Model spectra and coherences are calculated for idealized buoyancy frequency profiles and compared with the Garrett‐Munk model. Measurements in the upper 200 m from the Mixed Layer Dynamics Experiment in the northeast Pacific in 1983 are also compared with the model results. The most striking success of the model is predicting the observed high coherence and 180° phase difference across the mixed layer of horizontal velocity

Internal waves in the ocean: A review

This review documents the advances in our knowledge of the oceanic internal wave field during the past quadrennium. Emphasis is placed on studies that deal most directly with the measurement and modeling of internal waves as they exist in the ocean. Progress has come by realizing that specific physical processes might behave differently when embedded in the complex, omnipresent sea of internal waves. To understand fully the dynamics of the internal wave field requires knowledge of the simultaneous interactions of the internal waves with other oceanic phenomena as well as with themselves.Copyrighted by American Geophysical Union