19,601 research outputs found
Profiling of micrometer sized laser beams in restricted volumes
We present a method for determining the 3D intensity distribution of directed
laser radiation with micrometer resolution in restricted volumes. Our method is
based on in-coupling and guiding properties of optical fibers, with the current
version requiring only few hundred micrometers. We characterize the performance
of the method and experimentally demonstrate profiling of micrometer sized
laser beams. We discuss the limiting factors and routes towards a further
increase of the resolution and beam profiling in even more restricted volumes.
Finally, as an application example, we present profiling of laser beams inside
a micro ion trap with integrated optical fibers
IMPACT OF US AND EUROPEAN BIOFUEL POLICIES ON FOREST CARBON
This paper develops a dynamic, regional analysis of the effects of US and European biofuel mandates on land use, forestry stocks, and carbon emissions. The results suggest that these mandates may cause an additional 23-26 million hectares of forestland losses globally, but additional carbon emissions of 1.2 – 1.6 billion t CO2. The estimates are found to be sensitive to the elasticity parameter on the land supply function in the model, with the higher elasticity estimates associated with larger carbon losses. The regional analysis turns out to be quite important, because some regions end up gaining forestland and increasing carbon stocks. The regional and dynamic effects have been missed by most other noteworthy analyses of the induced land use effects of biofuel policies, potentially leading the authors to overstate the impacts by 3-6 times.Biofuel policy, Indirect land use effects, Forest carbon sequestration, Environmental Economics and Policy, Land Economics/Use, Resource /Energy Economics and Policy,
U.S. Gun Violence in 2021: An Accounting of a Public Health Crisis
Each year it is our mission to provide policymakers and the public accurate and up-to date data on gun fatalities and illustrate the enormous toll gun violence has on our country. This report is an update of "A Year in Review: 2020 Gun Deaths in the U.S." It uses 2021 firearm fatality data released by the CDC in January 2023.We recognize that each data point discussed in this report is a person who died by gun violence. This loss has an immeasurable impact on families, friends, and communities; data can only partly illuminate the true burden of gun violence. In addition to analyzing the data, we must listen to and uplift the voices of those directly impacted by gun violence, their loved ones, and their communities.Yet even on its own, the 2021 CDC data paints an alarming picture of the epidemic of gun violence. It illustrates how people from all walks of life are impacted. These deaths, and the associated pain and suffering, can be prevented. By leveraging the data outlined in this report, we can improve gun violence prevention strategies and create a more peaceful future, free from gun violence
The 2HA line of Medicago truncatula has characteristics of an epigenetic mutant that is weakly ethylene insensitive
BACKGROUND The Medicago truncatula 2HA seed line is highly embryogenic while the parental line Jemalong rarely produces embryos. The 2HA line was developed from one of the rare Jemalong regenerates and this method for obtaining a highly regenerable genotype in M. truncatula is readily reproducible suggesting an epigenetic mechanism. Microarray transcriptomic analysis showed down regulation of an ETHYLENE INSENSITIVE 3-like gene in 2HA callus which provided an approach to investigating epigenetic regulation of genes related to ethylene signalling and the 2HA phenotype. Ethylene is involved in many developmental processes including somatic embryogenesis (SE) and is associated with stress responses. RESULTS Microarray transcriptomic analysis showed a significant number of up-regulated transcripts in 2HA tissue culture, including nodule and embryo specific genes and transposon-like genes, while only a few genes were down-regulated, including an EIN3-like gene we called MtEIL1. This reduced expression was associated with ethylene insensitivity of 2HA plants that was further investigated. The weak ethylene insensitivity affected root and nodule development. Sequencing of MtEIL1 found no difference between 2HA and wild-type plants. DNA methylation analysis of MtEIL1 revealed significant difference between 2HA and wild-type plants. Tiling arrays demonstrated an elevated level of miRNA in 2HA plants that hybridised to the antisense strand of the MtEIL1 gene. AFLP-like methylation profiling revealed more differences in DNA methylation between 2HA and wild-type. Segregation analysis demonstrated the recessive nature of the eil1 phenotype and the dominant nature of the SE trait. CONCLUSIONS We have demonstrated that EIL1 of Medicago truncatula (MtEIL1) is epigenetically silenced in the 2HA seed line. The possible cause is an elevated level of miRNA that targets its 3'UTR and is also associated with DNA methylation of MtEIL1. Down regulation of MtEIL1 makes it possible to form nodules in the presence of ethylene and affects root growth under normal conditions. Segregation analysis showed no association between MtEIL1 expression and SE in culture but the role and mechanism of ethylene signalling in the process of plant regeneration through SE requires further investigation. The work also suggests that epigenetic changes to a particular gene induced in culture can be fixed in regenerated plants.This work was funded by the Australian Research Council (CEO348212) through the ARC Centre of Excellence for Integrative Legume Research (CILR)
Solid-state metathesis reactions under pressure: A rapid route to crystalline gallium nitride
High pressure chemistry has traditionally involved applying pressure and increasing temperature until conditions become thermodynamically favorable for phase transitions or reactions to occur. Here, high pressure alone is used as a starting point for carrying out rapid, self-propagating metathesis reactions. By initiating chemical reactions under pressure, crystalline phases, such as gallium nitride, can be synthesized which are inaccessible when initiated from ambient conditions. The single-phase gallium nitride made by metathesis reactions under pressure displays significant photoluminescence intensity in the blue/ultraviolet region. The absence of size or surface-state effects in the photoluminescence spectra show that the crystallites are of micron dimensions. The narrow lines of the x-ray diffraction patterns and scanning electron microscopy confirm this conclusion. Brightly luminescent thin films can be readily grown using pulsed laser deposition
CAN DESIGN SCIENCE BE USED FOR DESIGN?
Design Science is currently much discussed in Information Systems research. In our analysis we distinguish two distinct threads in this discussion. The first thread is a meta-debate about the nature of IS research, and (in particular) how design work can properly be enacted as research. The second thread is a normative discussion of how design work should be conducted – important in a field where the principle objects of study are designed artefacts called information systems. If these principles for design have any consequence at all, they should be verifiable and they should be evaluated. In this research, conducted with student software designers at Aalborg University, we pose the question ‘can design science be used to build software?’ Ten experienced students in the Department of Computer Science participated in experiments to use design science theory as the principle inspiration for small software development projects. They studied the literature, chose appropriate starting theories, designed their own development processes, used them to build small mobile applications, documented their experiences and evaluated those experiences by writing research articles. A more experienced researcher helped organise the experiments and supervised the research. Students were surprisingly positive about their experiences with design science and the causes for this enthusiasm, and the underlying contribution of design science to the software developments are discussed
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The multikinase inhibitor RXDX-105 is effective against neuroblastoma in vitro and in vivo.
Neuroblastoma is the most common extracranial solid tumor of childhood and accounts for 15% of all pediatric cancer-related deaths. New therapies are needed to improve outcomes for children with high-risk and relapsed tumors. Inhibitors of the RET kinase and the RAS-MAPK pathway have previously been shown to be effective against neuroblastoma, suggesting that combined inhibition may have increased efficacy. RXDX-105 is a small molecule inhibitor of multiple kinases, including the RET and BRAF kinases. We found that treatment of neuroblastoma cells with RXDX-105 resulted in a significant decrease in cell viability and proliferation in vitro and in tumor growth and tumor vascularity in vivo. Treatment with RXDX-105 inhibited RET phosphorylation and phosphorylation of the MEK and ERK kinases in neuroblastoma cells and xenograft tumors, and RXDX-105 treatment induced both apoptosis and cell cycle arrest. RXDX-105 also showed enhanced efficacy in combination with 13-cis-retinoic acid, which is currently a component of maintenance therapy for children with high-risk neuroblastoma. Our results demonstrate that RXDX-105 shows promise as a novel therapeutic agent for children with high-risk and relapsed neuroblastoma
Characterisation of the legume SERK-NIK gene superfamily including splice variants: Implications for development and defence
<p>Abstract</p> <p>Background</p> <p><it>SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASE </it>(<it>SERK</it>) genes are part of the regulation of diverse signalling events in plants. Current evidence shows SERK proteins function both in developmental and defence signalling pathways, which occur in response to both peptide and steroid ligands. <it>SERKs </it>are generally present as small gene families in plants, with five <it>SERK </it>genes in Arabidopsis. Knowledge gained primarily through work on Arabidopsis SERKs indicates that these proteins probably interact with a wide range of other receptor kinases and form a fundamental part of many essential signalling pathways. The <it>SERK1 </it>gene of the model legume, <it>Medicago truncatula </it>functions in somatic and zygotic embryogenesis, and during many phases of plant development, including nodule and lateral root formation. However, other <it>SERK </it>genes in <it>M. truncatula </it>and other legumes are largely unidentified and their functions unknown.</p> <p>Results</p> <p>To aid the understanding of signalling pathways in <it>M. truncatula</it>, we have identified and annotated the <it>SERK </it>genes in this species. Using degenerate PCR and database mining, eight more <it>SERK</it>-like genes have been identified and these have been shown to be expressed. The amplification and sequencing of several different PCR products from one of these genes is consistent with the presence of splice variants. Four of the eight additional genes identified are upregulated in cultured leaf tissue grown on embryogenic medium. The sequence information obtained from <it>M. truncatula </it>was used to identify <it>SERK </it>family genes in the recently sequenced soybean (<it>Glycine max</it>) genome.</p> <p>Conclusions</p> <p>A total of nine <it>SERK </it>or <it>SERK-like </it>genes have been identified in <it>M. truncatula </it>and potentially 17 in soybean. Five <it>M. truncatula SERK </it>genes arose from duplication events not evident in soybean and Lotus. The presence of splice variants has not been previously reported in a <it>SERK </it>gene. Upregulation of four newly identified <it>SERK </it>genes (in addition to the previously described <it>MtSERK1</it>) in embryogenic tissue cultures suggests these genes also play a role in the process of somatic embryogenesis. The phylogenetic relationship of members of the <it>SERK </it>gene family to closely related genes, and to development and defence function is discussed.</p
Promoting Diversity, Equity, and Inclusion: An Examination of Diversity-Infused Faculty Professional Development Programs
Given the national and global demographic trends, diversity, equity, and inclusion (DEI) are topics of discussion in U.S. higher education institutions. Most post-secondary institutions include DEI initiatives and mission statements, including implementing inclusive frameworks and approaches. These approaches include universal design for learning (UDL), inclusive pedagogy, or multicultural education. The UDL approach and inclusive teaching practices allow university faculty and staff to teach with a structural design that could accommodate diverse learning needs and provide the additional support or differentiation needed for vulnerable or marginalized students. In this study, we infused DEI-focused inclusive pedagogy into faculty professional development (PD) programs such as workshops, events, courses, and additional resources. Qualitative data from the follow-up survey demonstrated the instructors’ positive attitudes and adoption of inclusive teaching practices reflecting UDL principles. The findings of this study indicate practical implications for instructional design and the development of faculty PD programs in higher education
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