7,550 research outputs found
EXPANDING ORGANIZATIONAL TRANSACTIVE MEMORY ASYNCHRONOUSLY: THE EFFECT OF EXPERTISE
Organizations learn by sharing information. While filtering may exclude potentially valuable information, information overload may prevent the adequate identification of important information. Lee andBrooks [1993] report on the introduction of a document classification and information dissemination system for soft information. There was an initial concern that users would use high priority categories excessively within the grapeVINE system, thereby reducing the effectiveness of the filtering process. In fact, Lee and Brook found that people tended to undervalue their contributions and not put a high enough priority on their contribution. A large percent of the information in the grapeVINE system was added at low priority, causing the information not to be shared. A major advantage touted of groups is the potential for pooling unshared information and thereby improving task accomplishment. Stasser found that groups tend to discuss topics that they have in common(shared information) more then their unique knowledge (unshared information) [Stewart, 1992]. Based on social validation theory, Stewart [1992] predicted and found evidence that telling someone he or she is an expert, separately and in front of the other members of a group, increased the proportion of unshared information. This paper explores the affect of expertise on organizational transactive memory with respect to the filtering and sharing of information. First transactive organizational memory is briefly discussed, followed by relevant aspects of social validation theory and a description of the filtering and sharing model embodied in Brook\u27s classification and dissemination system. We then describe the experimental design used to isolate the effects of expertise on the filtering and sharing of information, present results, and discuss their implications
First Results from the KMOS Lens-Amplified Spectroscopic Survey (KLASS): Kinematics of Lensed Galaxies at Cosmic Noon
We present the first results of the KMOS Lens-Amplified Spectroscopic Survey
(KLASS), a new ESO Very Large Telescope (VLT) large program, doing multi-object
integral field spectroscopy of galaxies gravitationally lensed behind seven
galaxy clusters selected from the HST Grism Lens-Amplified Survey from Space
(GLASS). Using the power of the cluster magnification we are able to reveal the
kinematic structure of 25 galaxies at , in four
cluster fields, with stellar masses . This sample includes 5 sources at with lower stellar masses
than in any previous kinematic IFU surveys. Our sample displays a diversity in
kinematic structure over this mass and redshift range. The majority of our
kinematically resolved sample is rotationally supported, but with a lower ratio
of rotational velocity to velocity dispersion than in the local universe,
indicating the fraction of dynamically hot disks changes with cosmic time. We
find no galaxies with stellar mass in our sample
display regular ordered rotation. Using the enhanced spatial resolution from
lensing, we resolve a lower number of dispersion dominated systems compared to
field surveys, competitive with findings from surveys using adaptive optics. We
find that the KMOS IFUs recover emission line flux from HST grism-selected
objects more faithfully than slit spectrographs. With artificial slits we
estimate slit spectrographs miss on average 60% of the total flux of emission
lines, which decreases rapidly if the emission line is spatially offset from
the continuum.Comment: Accepted for publication in Ap
Scalar Matter Coupled to Quantum Gravity in the Causal Approach: Finite One-Loop Calculations and Perturbative Gauge Invariance
Quantum gravity coupled to scalar massive matter fields is investigated
within the framework of causal perturbation theory. One-loop calculations
include matter loop graviton self-energy and matter self-energy and yield
ultraviolet finite and cutoff-free expressions. Perturbative gauge invariance
to second order implies the usual Slavnov-Ward identities for the graviton
self-energy in the loop graph sector and generates the correct quartic
graviton-matter interaction in the tree graph sector. The mass zero case is
also discussed.Comment: 37 pages, latex, no figures, some typos corrected, section 3 modifie
The Isolation, Culture, and Cryopreservation of Human Rectus Sheath Fibroblasts
The vast majority of pelvic and intra-abdominal surgery is undertaken through at least one incision, through either the linea alba or the rectus sheath. These connective tissue layers are formed from the aponeuroses of the rectus muscles (anterior and posterior rectus sheath) and are vital for the structural integrity of the abdominal wall. Poor healing of these connective tissues after surgery can lead to significant morbidity for patients, who can develop unsightly and painful incisional hernias. Fibroblasts within the rectus sheath are responsible for laying down and remodeling collagen during the healing process after surgery. Despite their importance for this healing process, such cells have not been studied in vitro. In order to carry out such work, researchers must first be able to isolate these cells from human tissue and culture them successfully so they may be used for experimentation. This article provides an extensive and detailed protocol for the isolation, culture, cryopreservation, and thawing of human rectus sheath fibroblasts (RSFs). In our hands, this protocol develops confluent cultures of primary fibroblasts within 2 weeks, and sufficient cultures ready for freezing and storage after a further 2 to 4 weeks. © 2023 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol: Collagenase digestion of human rectus sheath and isolation of RSFs Alternate Protocol: Collagenase digestion of human rectus sheath and isolation of RSFs, digestion in flask Support Protocol: Cryopreservation and thawing of human RSFs
Impacts of COVID-19 on the value chain of the hake small scale fishery in northern Peru
The supply chain mapping and analysis of secondary sources was supported by The Walton Family Foundation (Grant 2019-319) and the estimation of COVID-19 impacts by a 2019–20 SFC-ODA GCRF (University of St Andrews) Grant.All aspects of fish supply chains have been severely affected by the COVID-19 pandemic, with jobs, income and food security at risk. In Peru, small scale fisheries are fundamental for food security, contributing to about 2/3 of all fish consumed nationally. One of the most important resources which is more affordable for local and regional consumption is hake (Merluccius gayi peruanus). This study is a first attempt to describe the small-scale hake fishery value chain and to quantify the impact of COVID-19 from March to August 2020 in two fishing communities in northern Peru. The levels of fishing and primary buying were the most affected, and we estimate that ~ 23,000 fishing trips were not conducted, ~ 1680 t of hake was not landed (83% decrease), and 620 jobs were negatively impacted during this period. The gross income of vessel owners and primary buyers decreased by ~ $US 913,000. Marked differences were observed in the way each community responded to the pandemic and in their resilience to cope with COVID-19, despite being located less than 10 km away. In El Ñuro, which relied more heavily on the international market for hake trade, the value chain was affected for longer, while in Los Órganos which supplied national markets, the chain was restored after an initial period of adjustment. Our study suggests that government efforts should focus on facilitating a formalisation process in all levels of the chain, develop indicators to monitor the resumption of activities and the inclusion of a value chain approach to small-scale fisheries management.Publisher PDFPeer reviewe
A highly-ionized region surrounding SN Refsdal revealed by MUSE
Supernova (SN) Refsdal is the first multiply-imaged, highly-magnified, and
spatially-resolved SN ever observed. The SN exploded in a highly-magnified
spiral galaxy at z=1.49 behind the Frontier Fields Cluster MACS1149, and
provides a unique opportunity to study the environment of SNe at high z. We
exploit the time delay between multiple images to determine the properties of
the SN and its environment, before, during, and after the SN exploded. We use
the integral-field spectrograph MUSE on the VLT to simultaneously target all
observed and model-predicted positions of SN Refsdal. We find MgII emission at
all positions of SN Refsdal, accompanied by weak FeII* emission at two
positions. The measured ratios of [OII] to MgII emission of 10-20 indicate a
high degree of ionization with low metallicity. Because the same high degree of
ionization is found in all images, and our spatial resolution is too coarse to
resolve the region of influence of SN Refsdal, we conclude that this high
degree of ionization has been produced by previous SNe or a young and hot
stellar population. We find no variability of the [OII] line over a period of
57 days. This suggests that there is no variation in the [OII] luminosity of
the SN over this period, or that the SN has a small contribution to the
integrated [OII] emission over the scale resolved by our observations.Comment: 5 pages, 4 figures, accepted for publication in A&
The story of supernova 'Refsdal' told by MUSE
We present MUSE observations in the core of the HFF galaxy cluster MACS
J1149.5+2223, where the first magnified and spatially-resolved multiple images
of SN 'Refsdal' at redshift 1.489 were detected. Thanks to a DDT program with
the VLT and the extraordinary efficiency of MUSE, we measure 117 secure
redshifts with just 4.8 hours of total integration time on a single target
pointing. We spectroscopically confirm 68 galaxy cluster members, with redshift
values ranging from 0.5272 to 0.5660, and 18 multiple images belonging to 7
background, lensed sources distributed in redshifts between 1.240 and 3.703.
Starting from the combination of our catalog with those obtained from extensive
spectroscopic and photometric campaigns using the HST, we select a sample of
300 (164 spectroscopic and 136 photometric) cluster members, within
approximately 500 kpc from the BCG, and a set of 88 reliable multiple images
associated to 10 different background source galaxies and 18 distinct knots in
the spiral galaxy hosting SN 'Refsdal'. We exploit this valuable information to
build 6 detailed strong lensing models, the best of which reproduces the
observed positions of the multiple images with a rms offset of only 0.26". We
use these models to quantify the statistical and systematic errors on the
predicted values of magnification and time delay of the next emerging image of
SN 'Refsdal'. We find that its peak luminosity should should occur between
March and June 2016, and should be approximately 20% fainter than the dimmest
(S4) of the previously detected images but above the detection limit of the
planned HST/WFC3 follow-up. We present our two-dimensional reconstruction of
the cluster mass density distribution and of the SN 'Refsdal' host galaxy
surface brightness distribution. We outline the roadmap towards even better
strong lensing models with a synergetic MUSE and HST effort.Comment: 21 pages, 9 figures, 6 tables; accepted for publication in the
Astrophysical Journal - extra information on data analysis added, all model
predictions and results unchange
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