A Call for a Humanistic Stance Toward K–12 Data Science Education

There is growing interest in how to better prepare K–12 students to work with data. In this article, we assert that these discussions of teaching and learning must attend to the human dimensions of data work. Specifically, we draw from several established lines of research to argue that practices involving the creation and manipulation of data are shaped by a combination of personal experiences, cultural tools and practices, and political concerns. We demonstrate through two examples how our proposed humanistic stance highlights ways that efforts to make data personally relevant for youth also necessarily implicate cultural and sociopolitical dimensions that affect the design and learning opportunities in data-rich learning environments. We offer an interdisciplinary framework based on literature from multiple bodies of educational research to inform design, teaching and research for more effective, responsible, and inclusive student learning experiences with and about data

Colloidal transport through optical tweezer arrays

Viscously damped particles driven past an evenly spaced array of potential energy wells or barriers may become kinetically locked in to the array, or else may escape from the array. The transition between locked-in and free-running states has been predicted to depend sensitively on the ratio between the particles' size and the separation between wells. This prediction is confirmed by measurements on monodisperse colloidal spheres driven through arrays of holographic optical traps.Comment: 4 pages, 4 figure

Condensation in ideal Fermi gases

I investigate the possibility of condensation in ideal Fermi systems of general single particle density of states. For this I calculate the probability $w_{N_0}$ of having exactly $N_0$ particles in the condensate and analyze its maxima. The existence of such maxima at macroscopic values of $N_0$ indicates a condensate. An interesting situation occurs for example in 1D systems, where $w_{N_0}$ may have two maxima. One is at $N_0=0$ and another one may exist at finite $N_0$ (for temperatures bellow a certain condensation temperature). This suggests the existence of a first order phase transition. % The calculation of $w_{N_0}$ allows for the exploration of ensemble equivalence of Fermi systems from a new perspective.Comment: 8 pages with 1 figure. Will appear in J. Phys. A: Math. Gen. Changes (minor): I updated Ref. [9] and its citation in the text. I introduced citation for figure 1 in the tex

Quasi-Gaussian Statistics of Hydrodynamic Turbulence in 3/4+\epsilon dimensions

The statistics of 2-dimensional turbulence exhibit a riddle: the scaling exponents in the regime of inverse energy cascade agree with the K41 theory of turbulence far from equilibrium, but the probability distribution functions are close to Gaussian like in equilibrium. The skewness \C S \equiv S_3(R)/S^{3/2}_2(R) was measured as \C S_{\text{exp}}\approx 0.03. This contradiction is lifted by understanding that 2-dimensional turbulence is not far from a situation with equi-partition of enstrophy, which exist as true thermodynamic equilibrium with K41 exponents in space dimension of $d=4/3$. We evaluate theoretically the skewness \C S(d) in dimensions ${4/3}\le d\le 2$, show that \C S(d)=0 at $d=4/3$, and that it remains as small as \C S_{\text{exp}} in 2-dimensions.Comment: PRL, submitted, REVTeX 4, 4 page

Antifungal susceptibility and phenotypic characterization of oral isolates of a black fungus from a nasopharyngeal carcinoma patient under radiotherapy

10.1186/s12903-015-0023-9BMC Oral Health15

Modelling Carbon Emissions in Calluna vulgaris-Dominated Ecosystems when Prescribed Burning and Wildfires Interact

A present challenge in fire ecology is to optimize management techniques so that ecological services are maximized and C emissions minimized. Here, we modeled the effects of different prescribed-burning rotation intervals and wildfires on carbon emissions (present and future) in British moorlands. Biomass-accumulation curves from four Calluna-dominated ecosystems along a north-south gradient in Great Britain were calculated and used within a matrix-model based on Markov Chains to calculate above-ground biomass-loads and annual C emissions under different prescribed-burning rotation intervals. Additionally, we assessed the interaction of these parameters with a decreasing wildfire return intervals. We observed that litter accumulation patterns varied between sites. Northern sites (colder and wetter) accumulated lower amounts of litter with time than southern sites (hotter and drier). The accumulation patterns of the living vegetation dominated by Calluna were determined by site-specific conditions. The optimal prescribed-burning rotation interval for minimizing annual carbon emissions also differed between sites: the optimal rotation interval for northern sites was between 30 and 50 years, whereas for southern sites a hump-backed relationship was found with the optimal interval either between 8 to 10 years or between 30 to 50 years. Increasing wildfire frequency interacted with prescribed-burning rotation intervals by both increasing C emissions and modifying the optimum prescribed-burning interval for minimum C emission. This highlights the importance of studying site-specific biomass accumulation patterns with respect to environmental conditions for identifying suitable fire-rotation intervals to minimize C emissions.This project was supported financially by the BiodivERsA FIREMAN program (NERC/Defra: NE/G002096/1), the Ecological Continuity Trust and the Heather Trust. VMS was supported by ªBeatriu de PinoÂsº fellowship (2014BP-B 00056) from the Generalitat de Catalunya. JGA was supported by Juan de la Cierva-fellowship (IJCI- 2014-21393)

Synthetic alpha-synuclein fibrils cause mitochondrial impairment and selective dopamine neurodegeneration in part via iNOS-mediated nitric oxide production

Producción CientíficaIntracellular accumulation of α-synuclein (α-syn) are hallmarks of synucleinopathies, including Parkinson's disease (PD). Exogenous addition of preformed α-syn fibrils (PFFs) into primary hippocampal neurons induced α-syn aggregation and accumulation. Likewise, intrastriatal inoculation of PFFs into mice and non-human primates generates Lewy bodies and Lewy neurites associated with PD-like neurodegeneration. Herein, we investigate the putative effects of synthetic human PFFs on cultured rat ventral midbrain dopamine (DA) neurons. A time- and dose-dependent accumulation of α-syn was observed following PFFs exposure that also underwent phosphorylation at serine 129. PFFs treatment decreased the expression levels of synaptic proteins, caused alterations in axonal transport-related proteins, and increased H2AX Ser139 phosphorylation. Mitochondrial impairment (including modulation of mitochondrial dynamics-associated protein content), enhanced oxidative stress, and an inflammatory response were also detected in our experimental paradigm. In attempt to unravel a potential molecular mechanism of PFFs neurotoxicity, the expression of inducible nitric oxide synthase was blocked; a significant decline in protein nitration levels and protection against PFFs-induced DA neuron death were observed. Combined exposure to PFFs and rotenone resulted in an additive toxicity. Strikingly, many of the harmful effects found were more prominent in DA rather than non-DA neurons, suggestive of higher susceptibility to degenerate. These findings provide new insights into the role of α-syn in the pathogenesis of PD and could represent a novel and valuable model to study DA-related neurodegeneration

Local lung hypoxia determines epithelial fate decisions during alveolar regeneration.

After influenza infection, lineage-negative epithelial progenitors (LNEPs) exhibit a binary response to reconstitute epithelial barriers: activating a Notch-dependent ΔNp63/cytokeratin 5 (Krt5) remodelling program or differentiating into alveolar type II cells (AEC2s). Here we show that local lung hypoxia, through hypoxia-inducible factor (HIF1α), drives Notch signalling and Krt5pos basal-like cell expansion. Single-cell transcriptional profiling of human AEC2s from fibrotic lungs revealed a hypoxic subpopulation with activated Notch, suppressed surfactant protein C (SPC), and transdifferentiation toward a Krt5pos basal-like state. Activated murine Krt5pos LNEPs and diseased human AEC2s upregulate strikingly similar core pathways underlying migration and squamous metaplasia. While robust, HIF1α-driven metaplasia is ultimately inferior to AEC2 reconstitution in restoring normal lung function. HIF1α deletion or enhanced Wnt/β-catenin activity in Sox2pos LNEPs blocks Notch and Krt5 activation, instead promoting rapid AEC2 differentiation and migration and improving the quality of alveolar repair