As masterclasses internacionais em física de partículas em Portugal

Todos os anos, desde 2005, institutos de investigação e universidades de todo o mundo convidam estudantes do ensino secundário a experimentar a linha da frente da investigação fundamental. São as Masterclasses Internacionais em Física de Partículas, um programa do International Particle Physics Outreach Group (IPPOG) que oferece aos estudantes a oportunidade de serem cientistas por um dia, analisando dados reais recolhidos no acelerador LHC (Large Hadron Collider) do CERN, o Centro Europeu de Física de Partículas. Em 2015, participaram nas Masterclasses estudantes de 42 países, recebidos em 210 universidades e laboratórios. A participação de países de todo o mundo reflete a internacionalização das colaborações em Física de Partículas. Os estudantes vivenciam este aspeto na videoconferência com que terminam o seu dia de pesquisa, apresentando os resultados aos participantes de outros países, com a moderação de cientistas no CERN. Portugal participa desde a primeira edição, com a colaboração do LIP - Laboratório de Instrumentação e Física Experimental de Partículas, promotor nacional da atividade, e o apoio da Agência Ciência Viva. Em 2014, cerca de dois mil estudantes e centena e meia de professores participaram nas Masterclasses organizadas em 13 instituições do ensino superior um pouco por todo o País: de Faro a Braga e de Bragança a Ponta Delgada, passando por Beja, Évora, Lisboa, Covilhã, Coimbra, Aveiro, Porto e Vila Real. Foi ainda prestado apoio à realização das Masterclasses na Universidade de São Tomé e Príncipe. A dimensão e o sucesso das Masterclasses em Portugal não são a regra na generalidade dos países europeus, tendo-se notado um crescimento acentuado desde o inicio da realização de Escola de Física no CERN para professores em língua portuguesa. Nos últimos anos, verifica-se que cerca de 20% dos participantes nas Masterclasses são portugueses. Além da aquisição de conhecimentos ou da perceçâo do fascínio da investigação fundamental, aspetos como a cooperação internacional na ciência, a comunicação entre cientistas de diferentes línguas e culturas, ou a estreita relação de interdependência entre ciência fundamental e tecnologia, que o CERN tão bem representa, são aprendizagens a valorizar. Neste contexto, importa hoje sobretudo refletir sobre as formas de maximizar o ganho para todos os participantes

Limited effect of chronic valproic acid treatment in a mouse model of Machado-Joseph disease

Machado-Joseph disease (MJD) is an inherited neurodegenerative disease, caused by a CAG repeat expansion within the coding region of ATXN3 gene, and which currently lacks effective treatment. In this work we tested the therapeutic efficacy of chronic treatment with valproic acid (VPA) (200mg/kg), a compound with known neuroprotection activity, and previously shown to be effective in cell, fly and nematode models of MJD. We show that chronic VPA treatment in the CMVMJD135 mouse model had limited effects in the motor deficits of these mice, seen mostly at late stages in the motor swimming, beam walk, rotarod and spontaneous locomotor activity tests, and did not modify the ATXN3 inclusion load and astrogliosis in affected brain regions. However, VPA chronic treatment was able to increase GRP78 protein levels at 30 weeks of age, one of its known neuroprotective effects, confirming target engagement. In spite of limited results, the use of another dosage of VPA or of VPA in a combined therapy with molecules targeting other pathways, cannot be excluded as potential strategies for MJD therapeuticsPM received funding from Ataxia UK Grant (Project: Pharmacologic therapy for Machado-Joseph disease: from a C. elegans drug screen to a mouse model validation). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.info:eu-repo/semantics/publishedVersio

Habitat area and climate stability determine geographical variation in plant species range sizes

Despite being a fundamental aspect of biodiversity, little is known about what controls species range sizes. This is especially the case for hyperdiverse organisms such as plants. We use the largest botanical data set assembled to date to quantify geographical variation in range size for ∼ 85 000 plant species across the New World. We assess prominent hypothesised range-size controls, finding that plant range sizes are codetermined by habitat area and long- and short-term climate stability. Strong short- and long-term climate instability in large parts of North America, including past glaciations, are associated with broad-ranged species. In contrast, small habitat areas and a stable climate characterise areas with high concentrations of small-ranged species in the Andes, Central America and the Brazilian Atlantic Rainforest region. The joint roles of area and climate stability strengthen concerns over the potential effects of future climate change and habitat loss on biodiversity

Neuronal cell-based high-throughput screen for enhancers of mitochondrial function reveals luteolin as a modulator of mitochondria-endoplasmic reticulum coupling

Background: Mitochondrial dysfunction is a common feature of aging, neurodegeneration, and metabolic diseases. Hence, mitotherapeutics may be valuable disease modifiers for a large number of conditions. In this study, we have set up a large-scale screening platform for mitochondrial-based modulators with promising therapeutic potential. Results: Using differentiated human neuroblastoma cells, we screened 1200 FDA-approved compounds and identified 61 molecules that significantly increased cellular ATP without any cytotoxic effect. Following dose response curve-dependent selection, we identified the flavonoid luteolin as a primary hit. Further validation in neuronal models indicated that luteolin increased mitochondrial respiration in primary neurons, despite not affecting mitochondrial mass, structure, or mitochondria-derived reactive oxygen species. However, we found that luteolin increased contacts between mitochondria and endoplasmic reticulum (ER), contributing to increased mitochondrial calcium (Ca2+) and Ca2+-dependent pyruvate dehydrogenase activity. This signaling pathway likely contributed to the observed effect of luteolin on enhanced mitochondrial complexes I and II activities. Importantly, we observed that increased mitochondrial functions were dependent on the activity of ER Ca2+-releasing channels inositol 1,4,5-trisphosphate receptors (IP3Rs) both in neurons and in isolated synaptosomes. Additionally, luteolin treatment improved mitochondrial and locomotory activities in primary neurons and Caenorhabditis elegans expressing an expanded polyglutamine tract of the huntingtin protein. Conclusion: We provide a new screening platform for drug discovery validated in vitro and ex vivo. In addition, we describe a novel mechanism through which luteolin modulates mitochondrial activity in neuronal models with potential therapeutic validity for treatment of a variety of human diseases

Black Male Success in Mathematics: The Development of a Positive Mathematics Identity in Urban Schools

This study examined how Black males in rigorous mathematics courses at one U.S. urban high school explained the development of their positive mathematics identity. Drawing on students’ own voices, it aimed to provide a counter-narrative to dominant accounts depicting Black males as academic failures and to theories about their underachievement. The academic achievement gap, specifically in mathematics, between Black students and their White counterparts is well documented by quantitative studies. Researchers have developed several theories to explain the underachievement of Black males in mathematics. These studies position Black males as academically inferior and mathematics as a White male space. As researchers seek to bridge this gap, more nuanced approaches that include the socio-cultural and -political explanations Black males give for their success are essential. This study theorized the multi-dimensionality of Black male math identity and its relationship to the achievement gap. Positive mathematics identity development can account for the success of Black males who oppose the deficit-based rationale for Black male low performance. Drawing on critical race theory and phenomenological in-depth interview methods, this study documented a set of counter-stories that challenge the majoritarian discourse of racial privilege and explain how Black males develop their mathematics identity. The counter-stories illuminated the synthesis of two domains leading to the development of strong racial and academic identities, in defiance of racist stereotypes: (1) school supports that foster trust cultures in which discriminatory structures are dismantled and “otherness” opposed, and (2) families and community members who actively uphold the value of education. The findings suggest that the alignment of actions and messages from adults at home and at school can provide a consistent web of support for academic identities to flourish as students mediate their experience of societal racism in tandem with their mathematics achievement. Embedded in this counter-narrative is the intersectionality of race and immigrant identities, further complicating the dominant discourse on both Black males and immigrants and their academic identities. The implications for educators and policymakers wishing to close the achievement gap prompt a rethinking of schools to offer more equitable and humanizing spaces for Black males to learn and thrive

Depth Profiling of Defects in He Implanted SiO2SiO_2

Thin layer of $SiO_2$ thermally grown on p-type Si was implanted with $He^+$ ions at 30 keV with a dose of $5×10^{15}$ ions/$cm^2$. $SiO_2//Si$ samples were depth profiled by Doppler broadening positron annihilation spectroscopy to identify induced defects in the silicon oxide, at the interface and in the Si substrate. In one sample the silicon dioxide layer was removed by etching after implantation. It is shown that removing the silicon dioxide layer some more information about defects into the substrate can be found