920 research outputs found
Antioxidative Activities of Alfalfa and Timothy Varieties
The term functional foods is often used as a generic description for the beneficial effects of ingested foods that go beyond their traditional nutritive value (Bauman et al., 2001). Milk and dairy products are important dietary sources of nutrients, providing energy, high quality protein, and a variety of vitamins and minerals. Recent research has focused on altering the fat and protein content of milk and other dairy products in order to improve their nutrient content to more aptly reflect current dietary recommendations and trends. As a result, additional focus is being given to designing foods that have beneficial effects on human health. This study was carried out to investigate the antioxidative activities of forages grown in Korea
Yield and Nutritive Value of Heading and Headless Sorghum x Sudangrass Hybrids in Response to Cutting Frequency
Summer annual forages contribute greatly toward solving the problem of roughage supply for cattle in Korea. These forages support high levels of dairy and beef production during hot summer months when the quality and production of perennial herbage decreases due to unfavourable climatic conditions (Olson, 1971). This study investigated the effects of cutting frequency on dry matter (DM) yield and nutritive value of heading versus headless varieties of sorghum x sudangrass hybrid
Gravitational-wave Electromagnetic Counterpart Korean Observatory (GECKO): GECKO Follow-up Observation of GW190425
One of the keys to the success of multimessenger astronomy is the rapid
identification of the electromagnetic wave counterpart, kilonova (KN), of the
gravitational-wave (GW) event. Despite its importance, it is hard to find a KN
associated with a GW event, due to a poorly constrained GW localization map and
numerous signals that could be confused as a KN. Here, we present the
Gravitational-wave Electromagnetic wave Counterpart Korean Observatory (GECKO)
project, the GECKO observation of GW190425, and prospects of GECKO in the
fourth observing run (O4) of the GW detectors. We outline our follow-up
observation strategies during O3. In particular, we describe our
galaxy-targeted observation criteria that prioritize based on galaxy
properties. Armed with this strategy, we performed an optical and/or
near-infrared follow-up observation of GW190425, the first binary neutron star
merger event during the O3 run. Despite a vast localization area of 7460 deg^2,
we observed 621 host galaxy candidates, corresponding to 29.5% of the scores we
assigned, with most of them observed within the first 3 days of the GW event.
Ten transients were discovered during this search, including a new transient
with a host galaxy. No plausible KN was found, but we were still able to
constrain the properties of potential KNe using upper limits. The GECKO
observation demonstrates that GECKO can possibly uncover a GW170817-like KN at
a distance less than 200 Mpc if the localization area is of the order of
hundreds of square degrees, providing a bright prospect for the identification
of GW electromagnetic wave counterparts during the O4 run.Comment: 35 pages, 19 figures Accepted for publication in Ap
Evaluating implicit feedback models using searcher simulations
In this article we describe an evaluation of relevance feedback (RF) algorithms using searcher simulations. Since these algorithms select additional terms for query modification based on inferences made from searcher interaction, not on relevance information searchers explicitly provide (as in traditional RF), we refer to them as implicit feedback models. We introduce six different models that base their decisions on the interactions of searchers and use different approaches to rank query modification terms. The aim of this article is to determine which of these models should be used to assist searchers in the systems we develop. To evaluate these models we used searcher simulations that afforded us more control over the experimental conditions than experiments with human subjects and allowed complex interaction to be modeled without the need for costly human experimentation. The simulation-based evaluation methodology measures how well the models learn the distribution of terms across relevant documents (i.e., learn what information is relevant) and how well they improve search effectiveness (i.e., create effective search queries). Our findings show that an implicit feedback model based on Jeffrey's rule of conditioning outperformed other models under investigation
Effect of the GaAsP shell on optical properties of self-catalyzed GaAs nanowires grown on silicon
We realize growth of self-catalyzed core-shell GaAs/GaAsP nanowires (NWs) on
Si substrates using molecular-beam epitaxy. Transmission electron microscopy
(TEM) of single GaAs/GaAsP NWs confirms their high crystal quality and shows
domination of the zinc-blende phase. This is further confirmed in optics of
single NWs, studied using cw and time-resolved photoluminescence (PL). A
detailed comparison with uncapped GaAs NWs emphasizes the effect of the GaAsP
capping in suppressing the non-radiative surface states: significant PL
enhancement in the core-shell structures exceeding 2000 times at 10K is
observed; in uncapped NWs PL is quenched at 60K whereas single core-shell
GaAs/GaAsP NWs exhibit bright emission even at room temperature. From analysis
of the PL temperature dependence in both types of NW we are able to determine
the main carrier escape mechanisms leading to the PL quench
Deciphering the unusual stellar progenitor of GRB 210704A
GRB~210704A is a burst of intermediate duration (~s)
followed by a fading afterglow and an optical excess that peaked about 7 days
after the explosion. Its properties, and in particular those of the excess, do
not easily fit into the well established classification scheme of GRBs as being
long or short, leaving the nature of its progenitor uncertain. We present
multi-wavelength observations of the GRB and its counterpart, observed up to
160 days after the burst. In order to decipher the nature of the progenitor
system, we present a detailed analysis of the GRB high-energy properties
(duration, spectral lag, and Amati correlation), its environment, and late-time
optical excess. We discuss three possible scenarios: a neutron star merger, a
collapsing massive star, and an atypical explosion possibly hosted in a cluster
of galaxies. We find that traditional kilonova and supernova models do not
match well the properties of the optical excess, leaving us with the intriguing
suggestion that this event was an exotic high-energy merger.Comment: Revised version submitted to MNRAS after minor comments, 14 pages, 9
figure
THE TRANSFORMATIVE POTENTIAL OF CREATIVE ART PRACTICES IN THE CONTEXT OF INTERDISCIPLINARY RESEARCH
A growing body of literature addressing the need for educational innovations has also stressed the value of interdisciplinary approaches that incorporate art into teaching and learning. This paper aims to extend educators??? understanding of art???science interactions by presenting an empirical study that explores a unique art residency program created on the campus of a university that specializes in science and technology. The study reviews the art practices of three contemporary artists who participated in a program developed in conjunction with an interdisciplinary research project seeking ways to build an ecologically sustainable community and operated by a renewable energy resource-based economic system. Data that include observations, artist talks, and in-person interviews were collected from multiple sources during the residency to understand the distinguished processes involved in the development of individual art projects. A follow-up cross-case analysis revealed a few notable characteristics: connecting art with life through waste recycling, process-oriented practices highlighting resource circulation, and creating value using bricolage strategies. Regarding educational implications, discussions centered upon the potential transformational space identified from the creative art practices in the context of interdisciplinary research
The Rice SPOTTED LEAF4 (SPL4) Encodes a Plant Spastin That Inhibits ROS Accumulation in Leaf Development and Functions in Leaf Senescence
Lesion mimic mutants (LMMs) are usually controlled by single recessive mutations that cause the formation of necrotic lesions without pathogen invasion. These genetic defects are useful to reveal the regulatory mechanisms of defense-related programmed cell death in plants. Molecular evidence has been suggested that some of LMMs are closely associated with the regulation of leaf senescence in rice (Oryza sativa). Here, we characterized the mutation underlying spotted leaf4 (spl4), which results in lesion formation and also affects leaf senescence in rice. Map-based cloning revealed that the gamma ray-induced spl4-1 mutant has a single base substitution in the splicing site of the SPL4 locus, resulting in a 13-bp deletion within the encoded microtubule-interacting-and-transport (MIT) spastin protein containing an AAA-type ATPase domain. The T-DNA insertion spl4-2 mutant exhibited spontaneous lesions similar to those of the spl4-1 mutant, confirming that SPL4 is responsible for the LMM phenotype. In addition, both spl4 mutants exhibited delayed leaf yellowing during dark-induced or natural senescence. Western blot analysis of spl4 mutant leaves suggested possible roles for SPL4 in the degradation of photosynthetic proteins. Punctate signals of SPL4-fused fluorescent proteins were detected in the cytoplasm, similar to the cellular localization of animal spastin. Based on these findings, we propose that SPL4 is a plant spastin that is involved in multiple aspects of leaf development, including senescence
Ni(OH)2 Nanoplates Grown on Graphene as Advanced Electrochemical Pseudocapacitor Materials
Ni(OH)2 nanocrystals grown on graphene sheets with various degrees of
oxidation are investigated as electrochemical pseudocapacitor materials for
potential energy storage applications. Single-crystalline Ni(OH)2 hexagonal
nanoplates directly grown on lightly-oxidized, electrically-conducting graphene
sheets (GS) exhibit a high specific capacitance of ~1335F/g at a charge and
discharge current density of 2.8A/g and ~953F/g at 45.7A/g with excellent
cycling ability. The high specific capacitance and remarkable rate capability
are promising for applications in supercapacitors with both high energy and
power densities. Simple physical mixture of pre-synthesized Ni(OH)2 nanoplates
and graphene sheets show lower specific capacitance, highlighting the
importance of direct growth of nanomaterials on graphene to impart intimate
interactions and efficient charge transport between the active nanomaterials
and the conducting graphene network. Single-crystalline Ni(OH)2 nanoplates
directly grown on graphene sheets also significantly outperform small Ni(OH)2
nanoparticles grown on heavily-oxidized, electrically-insulating graphite oxide
(GO), suggesting that the electrochemical performance of these composites are
dependent on the quality of graphene substrates and the morphology and
crystallinity of the nanomaterials grown on top. These results suggest the
importance of rational design and synthesis of graphene-based nanocomposite
materials for high-performance energy applications.Comment: Published in JAC
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