299 research outputs found
Langdon Park Forest Patch: How three women turned their tree rescue efforts into a public-private partnership in community-based forest stewardship.
Early in the COVID-19 pandemic, community tree activists engaged in tree rescue activities in Washington, D.C.’s Langdon Park. They cleared non-native invasive vines and cataloged native tree species within the park’s 2.2-acre forest patch. Over the last 2+ years, they endeavored to share their story of forest stewardship, garnering support from district agencies and local non-profit Casey Trees. The ensuing collaboration has led to a healthier forest with greater community connection
Thermal transport measurements of individual multiwalled nanotubes
The thermal conductivity and thermoelectric power of a single carbon nanotube
were measured using a microfabricated suspended device. The observed thermal
conductivity is more than 3000 W/K m at room temperature, which is two orders
of magnitude higher than the estimation from previous experiments that used
macroscopic mat samples. The temperature dependence of the thermal conductivity
of nanotubes exhibits a peak at 320 K due to the onset of Umklapp phonon
scattering. The measured thermoelectric power shows linear temperature
dependence with a value of 80 V/K at room temperature.Comment: 4 pages, figures include
Effects of Methylprednisolone on the Neural Conduction of the Motor Evoked Potentials in Spinal Cord Injured Rats
Methylprednisolone (MP), a glucocorticoid steroid, has an anti-inflammatory action and seems to inhibit the formation of oxygen free radicals produced during lipid peroxidation in a spinal cord injury (SCI). However, the effects of MP on the functional recovery after a SCI is controversial. The present study was conducted to determine the effects of MP on the recovery of neural conduction following a SCI. A SCI was produced using the NYU spinal cord impactor. A behavioral test was conducted to measure neurological disorders, and motor evoked potentials (MEPs) were recorded. According to the behavioral test, using BBB locomotor scaling, MP-treated animals showed improved functional recoveries when compared to salinetreated animals. MEP latencies in the MP-treated group were shortened when compared to those in the control group. Peak amplitudes of MEPs were larger in the MP-treated group than those in the control group. The thresholds of MEPs tended to be lower in the MP-treated group than those in the control group. These results suggest that MP may improve functional recovery after a SCI
Computer-supported collaborative learning with digital video cases in teacher education: the impact of teaching experience on knowledge convergence
Case-based learning is ascribed high potential with respect to the education of pre-service teachers as well as the further education of experienced in-service teachers, as it can provide opportunities for the application of professional knowledge to authentic classroom situations. In addition to the application and acquisition of knowledge, the aspect of knowledge convergence (i.e., increasing similarity of collaborative learners with respect to their knowledge) should be taken into account when homogeneous benefits are desired for all participants of a case-based training. A field study with 29 pre-service teachers and 24 in-service teachers from adult education was conducted to examine effects of different levels of teaching experience on knowledge application, knowledge acquisition, and knowledge convergence in a computer-supported collaborative case-based learning environment. An innovative approach to measuring knowledge convergence was introduced, using the positions of annotations (i.e., flags placed on the timeline of the case video) made by learners during their case analyses as an indicator of their shared focus of attention. This measure was found to positively correlate with the application and acquisition of professional knowledge. Teaching experience affected both processes and outcomes of case-based learning, suggesting different means of instructional support for pre-service and in-service teachers
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Photochemically active DNA-intercalating ruthenium and related complexes – insights by combining crystallography and transient spectroscopy
Recent research on the study of the interaction of ruthenium polypyridyl compounds and defined sequence nucleic acids is reviewed. Particular emphasis is paid to complexes [Ru(LL)2(Int)]2+ containing potentially intercalating ligands (Int) such as dipyridophenazine (dppz), which are known to display light-switching or photo-oxidising behaviour, depending on the nature of the ancillary ligands. X-ray crystallography has made a key contribution to our understanding, and the first complete survey of structural results is presented. These include sequence, enantiomeric, substituent and structural specificities. The use of ultrafast transient spectrocopic methods to probe the ultrafast processes for complexes such as [Ru(TAP)2(dppz)]2+ and [Ru(phen)2(dppz)]2+ when bound to mixed sequence oligonucleotides are reviewed with particular attention being paid to the complementary advantages of transient (visible) absorption and time-resolved (mid) infra-red techniques to probe spectral changes in the metal complex and in the nucleic acid. The observed photophysical properties are considered in light of the structural information obtained from X-ray crystallography. In solution, metal complexes can be expected to bind at more than one DNA step, so that a perfect correlation of the photophysical properties and factors such as the orientation or penetration of the ligand into the intercalation pocket should not be expected. This difficulty can be obviated by carrying out TRIR studies in the crystals. Dppz complexes also undergo insertion, especially with mismatched sequences. Future areas for study such as those involving non-canonical forms of DNA, such as G-quadruplexes or i-motifs are also briefly considered
Metabolism within the tumor microenvironment and its implication on cancer progression: an ongoing therapeutic target
Since reprogramming energy metabolism is considered a new hallmark of cancer, tumor metabolism is again in the spotlight of cancer research. Many studies have been carried out and many possible therapies have been developed in the last years. However, tumor cells are not alone. A series of extracellular components and stromal cells, such as endothelial cells, cancer-associated fibroblasts, tumor-associated macrophages and tumor-infiltrating T cells, surround tumor cells in the so-called tumor microenvironment. Metabolic features of these cells are being studied in deep in order to find relationships between metabolism within the tumor microenvironment and tumor progression. Moreover, it cannot be forgotten that tumor growth is able to modulate host metabolism and homeostasis, so that tumor microenvironment is not the whole story. Importantly, the metabolic switch in cancer is just a consequence of the flexibility and adaptability of metabolism and should not be surprising. Treatments of cancer patients with combined therapies including anti-tumor agents with those targeting stromal cell metabolism, anti-angiogenic drugs and/or immunotherapy are being developed as promising therapeutics.Mª Carmen Ocaña is recipient of a predoctoral FPU grant from the Spanish Ministry of Education, Culture and Sport. Supported by grants BIO2014-56092-R (MINECO and FEDER), P12-CTS-1507 (Andalusian Government and FEDER) and funds from group BIO-267 (Andalusian Government). The "CIBER de Enfermedades Raras" is an initiative from the ISCIII (Spain). The funders had no role in the study design, data collection and analysis, decision to publish or preparation of the manuscript
The When and Why: Student Entrepreneurial Aspirations
Although connections between university enterprise courses and entrepreneurial activity have been examined, less work has investigated the intended timing of future entrepreneurial activities. Using data from a survey of U.K. business students, it is found that those intending to enter entrepreneurship right away place less emphasis on avoiding stress and responsibility, seeing themselves as natural leaders. They were also more confident of succeeding, but not because of superior knowledge. A greater emphasis on entrepreneurial activities in all institutional environments, including the corporate, may help balance the need to harness enthusiasm while it
lasts with the need to acquire relevant experience
Formation of dense partonic matter in relativistic nucleus-nucleus collisions at RHIC: Experimental evaluation by the PHENIX collaboration
Extensive experimental data from high-energy nucleus-nucleus collisions were
recorded using the PHENIX detector at the Relativistic Heavy Ion Collider
(RHIC). The comprehensive set of measurements from the first three years of
RHIC operation includes charged particle multiplicities, transverse energy,
yield ratios and spectra of identified hadrons in a wide range of transverse
momenta (p_T), elliptic flow, two-particle correlations, non-statistical
fluctuations, and suppression of particle production at high p_T. The results
are examined with an emphasis on implications for the formation of a new state
of dense matter. We find that the state of matter created at RHIC cannot be
described in terms of ordinary color neutral hadrons.Comment: 510 authors, 127 pages text, 56 figures, 1 tables, LaTeX. Submitted
to Nuclear Physics A as a regular article; v3 has minor changes in response
to referee comments. Plain text data tables for the points plotted in figures
for this and previous PHENIX publications are (or will be) publicly available
at http://www.phenix.bnl.gov/papers.htm
Osteopontin: A Novel Regulator at the Cross Roads of Inflammation, Obesity and Diabetes
Since its first description more than 20 years ago osteopontin has emerged as an active player in many physiological and pathological processes, including biomineralization, tissue remodeling and inflammation. As an extracellular matrix protein and proinflammatory cytokine osteopontin is thought to facilitate the recruitment of monocytes/macrophages and to mediate cytokine secretion in leukocytes. Modulation of immune cell response by osteopontin has been associated with various inflammatory diseases and may play a pivotal role in the development of adipose tissue inflammation and insulin resistance. Here we summarize recent findings on the role of osteopontin in metabolic disorders, particularly focusing on diabetes and obesity
Unraveling hadron structure with generalized parton distributions
The generalized parton distributions, introduced nearly a decade ago, have
emerged as a universal tool to describe hadrons in terms of quark and gluonic
degrees of freedom. They combine the features of form factors, parton densities
and distribution amplitudes--the functions used for a long time in studies of
hadronic structure. Generalized parton distributions are analogous to the
phase-space Wigner quasi-probability function of non-relativistic quantum
mechanics which encodes full information on a quantum-mechanical system. We
give an extensive review of main achievements in the development of this
formalism. We discuss physical interpretation and basic properties of
generalized parton distributions, their modeling and QCD evolution in the
leading and next-to-leading orders. We describe how these functions enter a
wide class of exclusive reactions, such as electro- and photo-production of
photons, lepton pairs, or mesons. The theory of these processes requires and
implies full control over diverse corrections and thus we outline the progress
in handling higher-order and higher-twist effects. We catalogue corresponding
results and present diverse techniques for their derivations. Subsequently, we
address observables that are sensitive to different characteristics of the
nucleon structure in terms of generalized parton distributions. The ultimate
goal of the GPD approach is to provide a three-dimensional spatial picture of
the nucleon, direct measurement of the quark orbital angular momentum, and
various inter- and multi-parton correlations.Comment: 370 pages, 62 figures; Dedicated to Anatoly V. Efremov on occasion of
his 70th anniversar
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