981 research outputs found
Beyond A Vision For The Future: Tangible Steps To Engage Diverse Participants In Inclusive Field Experiences
Synopsis Recent strides toward improving diversity, equity, and inclusion (DEI) in field biology present a unique opportunity for transdisciplinary exploration of the impacts and state of a topic that has remained hereto largely underexplored and under-discussed in the academic setting. Within current literature, themes of racial and gender inequity, power imbalances, unsafe environments, and underdeveloped infrastructure and resources are widespread. Thus, we organized a symposium that addressed these compelling issues in field biology DEI through a multitude of experiential and academic lenses. This article will orient the reader to the special issue and offer summative goals and outcomes of the symposium that can provide tangible steps toward creating meaningful improvements in the state of DEI and safety in field settings
Lower Critical Dimension of Ising Spin Glasses
Exact ground states of two-dimensional Ising spin glasses with Gaussian and
bimodal (+- J) distributions of the disorder are calculated using a
``matching'' algorithm, which allows large system sizes of up to N=480^2 spins
to be investigated. We study domain walls induced by two rather different types
of boundary-condition changes, and, in each case, analyze the system-size
dependence of an appropriately defined ``defect energy'', which we denote by
DE. For Gaussian disorder, we find a power-law behavior DE ~ L^\theta, with
\theta=-0.266(2) and \theta=-0.282(2) for the two types of boundary condition
changes. These results are in reasonable agreement with each other, allowing
for small systematic effects. They also agree well with earlier work on smaller
sizes. The negative value indicates that two dimensions is below the lower
critical dimension d_c. For the +-J model, we obtain a different result, namely
the domain-wall energy saturates at a nonzero value for L\to \infty, so \theta
= 0, indicating that the lower critical dimension for the +-J model exactly
d_c=2.Comment: 4 pages, 4 figures, 1 table, revte
Understanding person acquisition using an interactive activation and competition network
Face perception is one of the most developed visual skills that humans display, and recent work has attempted to examine the mechanisms involved in face perception through noting how neural networks achieve the same performance. The purpose of the present paper is to extend this approach to look not just at human face recognition, but also at human face acquisition. Experiment 1 presents empirical data to describe the acquisition over time of appropriate representations for newly encountered faces. These results are compared with those of Simulation 1, in which a modified IAC network capable of modelling the acquisition process is generated. Experiment 2 and Simulation 2 explore the mechanisms of learning further, and it is demonstrated that the acquisition of a set of associated new facts is easier than the acquisition of individual facts in isolation of one another. This is explained in terms of the advantage gained from additional inputs and mutual reinforcement of developing links within an interactive neural network system. <br/
Measurement of the Cross Sections and Analyzing Powers for Transitions in 58-Ni Using 200 MeV Proton Scattering
This research was sponsored by the National Science Foundation Grant NSF PHY-931478
Current reversal with type-I intermittency in deterministic inertia ratchets
The intermittency is investigated when the current reversal occurs in a
deterministic inertia ratchet system. To determine which type the intermittency
belongs to, we obtain the return map of velocities of particle using
stroboscopic recording, and numerically calculate the distribution of average
laminar length . The distribution follows the scaling law of , the characteristic relation of type-I
intermittency.Comment: 4 pages, 7 figure
Automated Detection of EUV Polar Coronal Holes During Solar Cycle 23
A new method for automated detection of polar coronal holes is presented.
This method, called perimeter tracing, uses a series of 171, 195, and 304 \AA\
full disk images from the Extreme ultraviolet Imaging Telescope (EIT) on SOHO
over solar cycle 23 to measure the perimeter of polar coronal holes as they
appear on the limbs. Perimeter tracing minimizes line-of-sight obscurations
caused by the emitting plasma of the various wavelengths by taking measurements
at the solar limb. Perimeter tracing also allows for the polar rotation period
to emerge organically from the data as 33 days. We have called this the Harvey
rotation rate and count Harvey rotations starting 4 January 1900. From the
measured perimeter, we are then able to fit a curve to the data and derive an
area within the line of best fit. We observe the area of the northern polar
hole area in 1996, at the beginning of solar cycle 23, to be about 4.2% of the
total solar surface area and about 3.6% in 2007. The area of the southern polar
hole is observed to be about 4.0% in 1996 and about 3.4% in 2007. Thus, both
the north and south polar hole areas are no more than 15% smaller now than they
were at the beginning of cycle 23. This compares to the polar magnetic field
measured to be about 40% less now than it was a cycle ago.Comment: 18 pagers, 7 figures, accepted to Solar Physic
Azimuthal Correlations in the Target Fragmentation Region of High Energy Nuclear Collisions
Results on the target mass dependence of proton and pion pseudorapidity
distributions and of their azimuthal correlations in the target rapidity range
are presented. The data have been taken with the
Plastic-Ball detector set-up for 4.9 GeV p + Au collisions at the Berkeley
BEVALAC and for 200 GeV/ p-, O-, and S-induced reactions on
different nuclei at the CERN-SPS. The yield of protons at backward rapidities
is found to be proportional to the target mass. Although protons show a typical
``back-to-back'' correlations, a ``side-by-side'' correlation is observed for
positive pions, which increases both with target mass and with impact parameter
of a collision. The data can consistently be described by assuming strong
rescattering phenomena including pion absorption effects in the entire excited
target nucleus.Comment: 7 pages, figures included, complete postscript available at
ftp://qgp.uni-muenster.de/pub/paper/azi-correlations.ps submitted to Phys.
Lett.
Genetic and phenotypic characterization of indolent T-cell lymphoproliferative disorders of the gastrointestinal tract.
Indolent T-cell lymphoproliferative disorders of the gastrointestinal tract are rare clonal T-cell diseases that more commonly occur in the intestines and have a protracted clinical course. Different immunophenotypic subsets have been described, but the molecular pathogenesis and cell of origin of these lymphocytic proliferations is poorly understood. Hence, we performed targeted next-generation sequencing and comprehensive immunophenotypic analysis of ten indolent T-cell lymphoproliferative disorders of the gastrointestinal tract, which comprised CD4 <sup>+</sup> (n=4), CD8 <sup>+</sup> (n=4), CD4 <sup>+</sup> /CD8 <sup>+</sup> (n=1) and CD4 <sup>-</sup> /CD8 <sup>-</sup> (n=1) cases. Genetic alterations, including recurrent mutations and novel rearrangements, were identified in 8/10 (80%) of these lymphoproliferative disorders. The CD4 <sup>+</sup> , CD4 <sup>+</sup> /CD8 <sup>+</sup> , and CD4 <sup>-</sup> /CD8 <sup>-</sup> cases harbored frequent alterations of JAK-STAT pathway genes (5/6, 82%); STAT3 mutations (n=3), SOCS1 deletion (n=1) and STAT3-JAK2 rearrangement (n=1), and 4/6 (67%) had concomitant mutations in epigenetic modifier genes (TET2, DNMT3A, KMT2D). Conversely, 2/4 (50%) of the CD8 <sup>+</sup> cases exhibited structural alterations involving the 3' untranslated region of the IL2 gene. Longitudinal genetic analysis revealed stable mutational profiles in 4/5 (80%) cases and acquisition of mutations in one case was a harbinger of disease transformation. The CD4 <sup>+</sup> and CD4 <sup>+</sup> /CD8 <sup>+</sup> lymphoproliferative disorders displayed heterogeneous Th1 (T-bet <sup>+</sup> ), Th2 (GATA3 <sup>+</sup> ) or hybrid Th1/Th2 (T-bet <sup>+</sup> /GATA3 <sup>+</sup> ) profiles, while the majority of CD8 <sup>+</sup> disorders and the CD4 <sup>-</sup> /CD8 <sup>-</sup> disease showed a type-2 polarized (GATA3 <sup>+</sup> ) effector T-cell (Tc2) phenotype. Additionally, CD103 expression was noted in 2/4 CD8 <sup>+</sup> cases. Our findings provide insights into the pathogenetic bases of indolent T-cell lymphoproliferative disorders of the gastrointestinal tract and confirm the heterogeneous nature of these diseases. Detection of shared and distinct genetic alterations of the JAK-STAT pathway in certain immunophenotypic subsets warrants further mechanistic studies to determine whether therapeutic targeting of this signaling cascade is efficacious for a proportion of patients with these recalcitrant diseases
Signatures of the slow solar wind streams from active regions in the inner corona
Some of local sources of the slow solar wind can be associated with
spectroscopically detected plasma outflows at edges of active regions
accompanied with specific signatures in the inner corona. The EUV telescopes
(e.g. SPIRIT/CORONAS-F, TESIS/CORONAS-Photon and SWAP/PROBA2) sometimes
observed extended ray-like structures seen at the limb above active regions in
1MK iron emission lines and described as "coronal rays". To verify the
relationship between coronal rays and plasma outflows, we analyze an isolated
active region (AR) adjacent to small coronal hole (CH) observed by different
EUV instruments in the end of July - beginning of August 2009. On August 1 EIS
revealed in the AR two compact outflows with the Doppler velocities V =10-30
km/s accompanied with fan loops diverging from their regions. At the limb the
ARCH interface region produced coronal rays observed by EUVI/STEREO-A on July
31 as well as by TESIS on August 7. The rays were co-aligned with open magnetic
field lines expanded to the streamer stalks. Using the DEM analysis, it was
found that the fan loops diverged from the outflow regions had the dominant
temperature of ~1 MK, which is similar to that of the outgoing plasma streams.
Parameters of the solar wind measured by STEREO-B, ACE, WIND, STEREO-A were
conformed with identification of the ARCH as a source region at the
Wang-Sheeley-Arge map of derived coronal holes for CR 2086. The results of the
study support the suggestion that coronal rays can represent signatures of
outflows from ARs propagating in the inner corona along open field lines into
the heliosphere.Comment: Accepted for publication in Solar Physics; 31 Pages; 13 Figure
The Landscape Archaeology of Knettishall Heath, Suffolk and its Implications
This paper briefly describes the results of archaeological fieldwork carried out in an area of heathland, currently managed as a nature reserve, in East Anglia. Although the earthworks recorded are for the most part unremarkable, they demonstrate the variety and intensity of human exploitation which shaped this ‘traditionally managed’ habitat. They also serve to emphasise the extent to which modern conservation management can radically change the long-term character of individual places
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