Effects of diamagnetic levitation on bacterial growth in liquid

Diamagnetic levitation is a technique that uses a strong, spatially-varying magnetic field to levitate diamagnetic materials, such as water and biological cells. This technique has the potential to simulate aspects of weightlessness, on the Earth. In common with all ground-based techniques to simulate weightlessness, however, there are effects introduced by diamagnetic levitation that are not present in space. Since there have been few studies that systematically investigate these differences, diamagnetic levitation is not yet being fully exploited. For the first time, we critically assess the effect of diamagnetic levitation on a bacterial culture in liquid. We used a superconducting magnet to levitate growing bacterial cultures for up to 18 hours, in a series of experiments to determine the effect of diamagnetic levitation on all phases of the bacterial growth cycle. We find that diamagnetic levitation increases the rate of population growth in a liquid culture. The speed of sedimentation of the bacterial cells to the bottom of the container is considerably reduced. Further experiments and microarray gene analysis show that the growth enhancement is due to greater oxygen availability in the magnetically levitated sample. We demonstrate that the magnetic field that levitates the cells also induces convective stirring in the liquid, an effect not present in microgravity. We present a simple theoretical model, showing how the paramagnetic force on dissolved oxygen can cause the liquid to become unstable to convection when the consumption of oxygen by the bacteria generates an oxygen concentration gradient. We propose that this convection enhances oxygen availability by transporting oxygen around the sample. Since convection is absent in space, these results are of significant importance and timeliness to researchers considering using diamagnetic levitation to explore weightless effects on living organisms and a broad range of other topics in the physical and life sciences

“Because we have really unique art”: Decolonizing Research with Indigenous Youth Using the Arts

Indigenous communities in Canada share a common history of colonial oppression. As a result, many Indigenous populations are disproportionately burdened with poor health outcomes, including HIV. Conventional public health approaches have not yet been successful in reversing this trend. For this study, a team of community- and university-based researchers came together to imagine new possibilities for health promotion with Indigenous youth. A strengths-based approach was taken that relied on using the energies and talents of Indigenous youth as a leadership resource. Art-making workshops were held in six different Indigenous communities across Canada in which youth could explore the links between community, culture, colonization, and HIV. Twenty artists and more than 85 youth participated in the workshops. Afterwards, youth participants reflected on their experiences in individual in-depth interviews. Youth participants viewed the process of making art as fun, participatory, and empowering; they felt that their art pieces instilled pride, conveyed information, raised awareness, and constituted a tangible achievement. Youth participants found that both the process and products of arts-based methods were important. Findings from this project support the notion that arts-based approaches to the development of HIV-prevention knowledge and Indigenous youth leadership are helping to involve a diverse cross-section of youth in a critical dialogue about health. Arts-based approaches represent one way to assist with decolonization for future generations

Childhood abuse and the content of delusions

Original article can be found at: http://www.sciencedirect.com/science/journal/01452134 Copyright Elsevier Ltd.We aimed to investigate possible associations between histories of childhood abuse and the content of delusions for individuals with psychotic disorders. 39 participants with a psychotic disorder including one or more delusional beliefs successfully completed structured interviews about childhood trauma, delusional beliefs and associated anomalous perceptual experiences including hallucinations. The presence of hallucinations was predicted by greater physical abuse. Greater abuse in general was associated with delusions involving ‘special abilities’ (grandiosity) and, at trend levels, with those involving ‘defective self’. Though preliminary, these results suggest that further investigation is warranted. The presence and nature of abuse may be relevant to delusional presentations and should form an essential part of clinical assessment of psychotic disorder.Peer reviewe

'Culture' as HIV prevention: Indigenous youth speak up!

This article explores the ways in which (a) Indigenous youth involved in an HIV intervention took up and reclaimed their cultures as a project of defining ‘self’, and (b) how Indigenous ‘culture’ can be used as a tool for resistance, HIV prevention and health promotion. Data were drawn from the Taking Action Project: Using arts-based approaches to develop Aboriginal youth leadership in HIV prevention. ‘By youth, for youth’ HIV education and awareness workshops were facilitated in six Indigenous communities across Canada, incorporating traditional and contemporary art forms to explore how youth perceived the links between structural inequality and HIV vulnerability. Over 100 youth participated, with 70 partaking in individual interviews to reflect on their experiences at the workshops. Interviews were audio-recorded, transcribed verbatim and analysed using NVivo software. Indigenous youth understood culture as a complex construct that included reconnecting to land, body, history, community and ceremony. For many youth, being Aboriginal and participating in cultural activities was seen as important for intergenerational healing, empowerment, health and combatting HIV. Youth spoke excitedly of their attempts to reclaim their languages and cultures despite barriers. They also understood art as a medium for self-expression and as an important site of cultural evolution.Our project demonstrates that the incorporation of culture within health strategies is important for effective HIV prevention amongst Indigenous youth. Reclaiming Indigenous cultures, languages and ceremonies may help to nurture future generations, diminish cycles of victimisation and combat hopelessness by reconnecting youth to stories of resistance and survival.Keywords: Indigenous youth, culture, HIV prevention, arts-based researc

Web Audio Modules 2.0: An Open Web Audio Plugin Standard

International audienceA group of academic researchers and developers from the computer music industry have joined forces for over a year to propose a new version of Web Audio Modules, an open source framework facilitating the development of high-performance Web Audio plugins (instruments, realtime audio effects and MIDI processors). While JavaScript and Web standards are becoming increasingly flexible and powerful, C, C++, and domain-specific languages such as FAUST or Csound remain the prevailing languages used by professional developers of native plugins. Fortunately, it is now possible to compile them in WebAssembly, which means they can be integrated with the Web platform. Our work aims to create a continuum between native and browser based audio app development and to appeal to programmers from both worlds. This paper presents our proposal including guidelines and implementations for an open Web Audio plugin standard-essentially the infrastructure to support high level audio plugins for the browser

Meristematic cell proliferation and ribosome biogenesis are decoupled in diamagnetically levitated Arabidopsis seedlings

Background: Cell growth and cell proliferation are intimately linked in the presence of Earth’s gravity, but are decoupled under the microgravity conditions present in orbiting spacecraft. New technologies to simulate microgravity conditions for long-duration experiments, with stable environmental conditions, in Earth-based laboratories are required to further our understanding of the effect of extraterrestrial conditions on the growth, development and health of living matter. Results: We studied the response of transgenic seedlings of Arabidopsis thaliana, containing either the CycB1-GUS proliferation marker or the DR5-GUS auxin-mediated growth marker, to diamagnetic levitation in the bore of a superconducting solenoid magnet. As a control, a second set of seedlings were exposed to a strong magnetic field, but not to levitation forces. A third set was exposed to a strong field and simulated hypergravity (2 g). Cell proliferation and cell growth cytological parameters were measured for each set of seedlings. Nucleolin immunodetection was used as a marker of cell growth. Collectively, the data indicate that these two fundamental cellular processes are decoupled in root meristems, as in microgravity: cell proliferation was enhanced whereas cell growth markers were depleted. These results also demonstrated delocalisation of auxin signalling in the root tip despite the fact that levitation of the seedling as a whole does not prevent the sedimentation of statoliths in the root cells. Conclusions:In our model system, we found that diamagnetic levitation led to changes that are very similar to those caused by real- [e.g. on board the International Space Station (ISS)] or mechanically-simulated microgravity [e.g. using a Random Positioning Machine (RPM)]. These changes decoupled meristematic cell proliferation from ribosome biogenesis, and altered auxin polar transport

X Chromosome Evolution in Cetartiodactyla

The mammalian X chromosome is characterized by high level of conservation. On the contrary the Cetartiodactyl X chromosome displays variation in morphology and G-banding pattern. It is hypothesized that X chromosome has undergone multiple rearrangements during Cetartiodactyla speciation. To investigate the evolution of this sex chromosome we have selected 26 BAC clones from cattle CHORI-240 library evenly distributed along the cattle X chromosome. High-resolution maps were obtained by fluorescence in situ hybridisation in a representative range of cetartiodactyl species from different families: pig (Suidae), gray whale (Eschrichtiidae), pilot whale (Delphinidae), hippopotamus (Hippopotamidae), Java mouse deer (Tragulidae), pronghorn (Antilocapridae), Siberian musk deer (Moschidae), giraffe (Giraffidae). To trace the X chromosome evolution during fast radiation in speciose families, we mapped more than one species in Cervidae (moose, Siberian roe deer, fallow deer and Pere David’s deer) and Bovidae (musk ox, goat, sheep, sable antelope, nilgau, gaur, saola, and cattle). We have identified three major conserved synteny blocks and based on this data reconstructed the structure of putative ancestral cetartiodactyl X chromosome. We demonstrate that intrachromosomal rearrangements such as inversions and centromere reposition are main drivers of cetartiodactyl’s chromosome X evolution

CUDASW++2.0: enhanced Smith-Waterman protein database search on CUDA-enabled GPUs based on SIMT and virtualized SIMD abstractions

<p>Abstract</p> <p>Background</p> <p>Due to its high sensitivity, the Smith-Waterman algorithm is widely used for biological database searches. Unfortunately, the quadratic time complexity of this algorithm makes it highly time-consuming. The exponential growth of biological databases further deteriorates the situation. To accelerate this algorithm, many efforts have been made to develop techniques in high performance architectures, especially the recently emerging many-core architectures and their associated programming models.</p> <p>Findings</p> <p>This paper describes the latest release of the CUDASW++ software, CUDASW++ 2.0, which makes new contributions to Smith-Waterman protein database searches using compute unified device architecture (CUDA). A parallel Smith-Waterman algorithm is proposed to further optimize the performance of CUDASW++ 1.0 based on the single instruction, multiple thread (SIMT) abstraction. For the first time, we have investigated a partitioned vectorized Smith-Waterman algorithm using CUDA based on the virtualized single instruction, multiple data (SIMD) abstraction. The optimized SIMT and the partitioned vectorized algorithms were benchmarked, and remarkably, have similar performance characteristics. CUDASW++ 2.0 achieves performance improvement over CUDASW++ 1.0 as much as 1.74 (1.72) times using the optimized SIMT algorithm and up to 1.77 (1.66) times using the partitioned vectorized algorithm, with a performance of up to 17 (30) billion cells update per second (GCUPS) on a single-GPU GeForce GTX 280 (dual-GPU GeForce GTX 295) graphics card.</p> <p>Conclusions</p> <p>CUDASW++ 2.0 is publicly available open-source software, written in CUDA and C++ programming languages. It obtains significant performance improvement over CUDASW++ 1.0 using either the optimized SIMT algorithm or the partitioned vectorized algorithm for Smith-Waterman protein database searches by fully exploiting the compute capability of commonly used CUDA-enabled low-cost GPUs.</p