1,167 research outputs found
Satellite-Based Management Tool for Oak Savanna Ecosystem Restoration
The structure and function of oak Quercus spp. savanna ecosystems in the North American Midwest were originally maintained by an active disturbance regime (often fire). Subsequent reductions in the frequency of disturbance after European settlement have facilitated rapid, regional conversion of these ecosystems to more closed-canopy forest. Hence, regional-scale management strategies are now needed to restore critical spatial gradients of light, temperature, soil moisture, and soil organic matter for recovery and sustenance of the unique mosaic of understory grass and forb species assemblages that define oak savannas. Tree species composition, distribution, mortality, basal area, and canopy cover are important forest structural parameters that are intrinsically linked to oak savanna restoration ecology. In this benchmark study, we seek to determine whether Landsat-based monitoring protocols can be developed as a tool to guide and monitor regional-scale restoration and management efforts. Using the Sherburne National Wildlife Refuge in central Minnesota as a test case, ground-based forest-structure data were collected and used with multitemporal Landsat sensor data and iterative exclusion partial least-squares regression to calibrate six predictive overstory structure models. Model calibrations produced moderate- to high-accuracy results with respective adjusted coefficient of determination and root mean-squared error values as follows: 0.859, 9.3% (canopy cover); 0.855, 2.95 m2 ha−1 (total basal area); 0.741, 11.6% (red oaks relative basal area); 0.781, 11.9% (bur oak relative basal area); 0.861, 3.20 m2 ha−1 (living oak basal area); and 0.833, 9.1% (dead oak relative basal area). We used the resulting structure models for the Sherburne test site to demonstrate how these data could be applied to help managers prioritize areas within management zones for restorative treatments. Although our Sherburne oak savanna test ecosystem is small (12,424 ha) compared with the size of a full Landsat scene (3.4 million ha), resulting structure models can be extended to the whole Landsat scene, which demonstrates how such modeling protocols can be used for repeated (e.g., annual to decadal), regional-scale analysis and assessment to improve management, planning, and implementation of oak savanna restoration efforts elsewhere
Low Temperature Co-Fired Ceramics for Micro-Fluidics
The miniaturization of analytical instruments and packaging of novel sensors is an area that has attracted significant research interest and offers many opportunities for product commercialization. Low Temperature Co-fired Ceramics (LTCC) is a materials system composed of alumina and glass in an organic binder. LTCC is a good choice for sensor development because of the ease of incorporating features in the ‘green’ or unfired state such as electrical traces, fluidic pathways and passive electrical components. After a firing cycle, what remains is a robust, monolithic device with features embedded in the package. In order for LTCC to be a successful medium for small scale sensors or lab-in-package devices, fluid flow through channels and inlet/outlet ports must be perfected. Device inlet/outlet ports have been demonstrated by embedding sapphire tubes in LTCC, allowing external connections using compression fittings. Channels and cavities have been fabricated through the use of sacrificial carbon tapes and pastes. A field flow fractionation device used for separating or concentrating constituent components in a fluid and a multi-electrode electrochemical cell were fabricated with the techniques described in this paper
Breastfeeding duration and residential isolation amid Aboriginal children in Western Australia
Objectives: To examine factors that impact on breastfeeding duration among Western Australian Aboriginal children. We hypothesised that Aboriginal children living in remote locations in Western Australia were breastfed for longer than those living in metropolitan locations. Methods: A population-based cross-sectional survey was conducted from 2000 to 2002 in urban, rural and remote settings across Western Australia. Cross-tabulations and multivariate logistic regression analyses were performed, using survey weights to produce unbiased estimates for the population of Aboriginal children. Data on demographic, maternal and infant characteristics were collected from 3932 Aboriginal birth mothers about their children aged 0–17 years (representing 22,100 Aboriginal children in Western Australia). Results: 71% of Aboriginal children were breastfed for three months or more. Accounting for other factors, there was a strong gradient for breastfeeding duration by remoteness, with Aboriginal children living in areas of moderate isolation being 3.2 times more likely to be breastfed for three months or more (p <0.001) compared to children in metropolitan Perth. Those in areas of extreme isolation were 8.6 times more likely to be breastfed for three months or longer (p <0.001). Conclusions: Greater residential isolation a protective factor linked to longer breastfeeding duration for Aboriginal children in our West Australian cohort
Defining a Flexible Notion of “Good” STEM Writing Across Contexts: Lessons Learned From a Cross-Institutional Conversation
We respond to a surging interest in science communication training for graduate scientists by advocating for a focus on rhetorically informed approaches to STEM writing and its assessment. We argue that STEM communication initiatives would benefit by shifting from a strategic focus on products to a flexible understanding of writing as a practice worthy of attention and study. To do that, we use our experience across two universities and two distinct programmatic contexts to train STEM graduate students in writing and communication. We draw from cross-disciplinary conversations to identify four facets of “good” STEM writing: (1) connecting to the big picture; (2) explaining science; (3) adhering to genre conventions; and (4) choosing context-appropriate language. We then describe our ongoing conversations across contexts to develop and implement flexible rubrics that capture and foster conversations around “good” writing. In doing so, we argue for a notion of writing rubrics as boundary objects, capable of fostering cross-disciplinary, integrative conversations and collaborations that strengthen student writing, shift STEM students toward a rhetorically informed sense of “good” writing, and offer that kinds of assessment data that make for persuasive evidence of the power of writing-centric approaches for STEM administrators and funders
Beyond the Bandwagon: Curating Cultural Memory at Milner Library
Archival and manuscript materials record human experience; they document how people have lived, worked, interacted, and thought about the world. These unique or rare materials make visible the experience and impact of individuals and organizations within their respective cultural, geographical, historical, local, and educational milieu. By exploring such documents and objects, patrons can see and investigate these relationships firsthand. Primary sources form the bedrock of humanistic research, personal inquiry, and engaged teaching. With this volume, we invite you to explore the unique and rare materials housed in Milner Library’s Special Collections and Dr. Jo Ann Rayfield University Archives as well as the services that bring them to life for readers worldwide. Contributed essays from scholars and collection stewards highlight how a small sample of these rich collections facilitate teaching and learning within the Illinois State University community and beyond.https://ir.library.illinoisstate.edu/mlp/1032/thumbnail.jp
Decidable fragments of first-order temporal logics
Accepted versio
The XMM Cluster Survey: X-ray analysis methodology
The XMM Cluster Survey (XCS) is a serendipitous search for galaxy clusters
using all publicly available data in the XMM-Newton Science Archive. Its main
aims are to measure cosmological parameters and trace the evolution of X-ray
scaling relations. In this paper we describe the data processing methodology
applied to the 5,776 XMM observations used to construct the current XCS source
catalogue. A total of 3,675 > 4-sigma cluster candidates with > 50
background-subtracted X-ray counts are extracted from a total non-overlapping
area suitable for cluster searching of 410 deg^2. Of these, 993 candidates are
detected with > 300 background-subtracted X-ray photon counts, and we
demonstrate that robust temperature measurements can be obtained down to this
count limit. We describe in detail the automated pipelines used to perform the
spectral and surface brightness fitting for these candidates, as well as to
estimate redshifts from the X-ray data alone. A total of 587 (122) X-ray
temperatures to a typical accuracy of < 40 (< 10) per cent have been measured
to date. We also present the methodology adopted for determining the selection
function of the survey, and show that the extended source detection algorithm
is robust to a range of cluster morphologies by inserting mock clusters derived
from hydrodynamical simulations into real XMM images. These tests show that the
simple isothermal beta-profiles is sufficient to capture the essential details
of the cluster population detected in the archival XMM observations. The
redshift follow-up of the XCS cluster sample is presented in a companion paper,
together with a first data release of 503 optically-confirmed clusters.Comment: MNRAS accepted, 45 pages, 38 figures. Our companion paper describing
our optical analysis methodology and presenting a first set of confirmed
clusters has now been submitted to MNRA
Interannual variations in continental-scale net carbon exchange and sensitivity to observing networks estimated from atmospheric CO2 inversions for the period 1980 to 2005
Author Posting. © American Geophysical Union, 2008. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Global Biogeochemical Cycles 22 (2008): GB3025, doi:10.1029/2007GB003082.Interannually varying net carbon exchange fluxes from the TransCom 3 Level 2 Atmospheric Inversion Intercomparison Experiment are presented for the 1980 to 2005 time period. The fluxes represent the model mean, net carbon exchange for 11 land and 11 ocean regions after subtraction of fossil fuel CO2 emissions. Both aggregated regional totals and the individual regional estimates are accompanied by a model uncertainty and model spread. We find that interannual variability is larger on the land than the ocean, with total land exchange correlated to the timing of both El Niño/Southern Oscillation (ENSO) as well as the eruption of Mt. Pinatubo. The post-Pinatubo negative flux anomaly is evident across much of the tropical and northern extratropical land regions. In the oceans, the tropics tend to exhibit the greatest level of interannual variability, while on land, the interannual variability is slightly greater in the tropics and northern extratropics. The interannual variation in carbon flux estimates aggregated by land and ocean across latitudinal bands remains consistent across eight different CO2 observing networks. The interannual variation in carbon flux estimates for individual flux regions remains mostly consistent across the individual observing networks. At all scales, there is considerable consistency in the interannual variations among the 13 participating model groups. Finally, consistent with other studies using different techniques, we find a considerable positive net carbon flux anomaly in the tropical land during the period of the large ENSO in 1997/1998 which is evident in the Tropical Asia, Temperate Asia, Northern African, and Southern Africa land regions. Negative anomalies are estimated for the East Pacific Ocean and South Pacific Ocean regions. Earlier ENSO events of the 1980s are most evident in southern land positive flux anomalies
A Large Sample of BL Lacs from SDSS and FIRST
We present a large sample of 501 radio-selected BL Lac candidates from the
combination of the Sloan Digital Sky Survey (SDSS) Data Release 5 optical
spectroscopy and from the Faint Images of the Radio Sky at Twenty-Centimeters
(FIRST) radio survey; this is one of the largest BL Lac samples yet assembled,
and each object emerges with homogeneous data coverage. Each candidate is
detected in the radio from FIRST and confirmed in SDSS optical spectroscopy to
have: (1) no emission feature with measured rest equivalent width larger than 5
Angstroms; and (2) no measured Ca II H/K depression larger than 40%. We
subdivide our sample into 426 higher confidence candidates and 75 lower
confidence candidates. We argue that contamination from other classes of
objects that formally pass our selection criteria is small, and we identify a
few very rare radio AGN with unusual spectra that are probably related to broad
absorption line quasars. About one-fifth of our sample were known BL Lacs prior
to the SDSS. A preliminary analysis of the sample generally supports the
standard beaming paradigm. While we recover sizable numbers of low-energy and
intermediate-energy cutoff BL Lacs (LBLs and IBLs, respectively), there are
indications of a potential bias toward recovering high-energy cutoff BL Lacs
(HBLs) from SDSS spectroscopy. Such a large sample may eventually provide new
constraints on BL Lac unification models and their potentially peculiar cosmic
evolution; in particular, our sample contains a significant number of higher
redshift objects, a sub-population for which the standard paradigm has yet to
be rigorously constrained.Comment: 16 pages, 13 figures, 6 tables. Accepted for Publication in the
Astronomical Journa
Search for Kaluza-Klein Graviton Emission in Collisions at TeV using the Missing Energy Signature
We report on a search for direct Kaluza-Klein graviton production in a data
sample of 84 of \ppb collisions at = 1.8 TeV, recorded
by the Collider Detector at Fermilab. We investigate the final state of large
missing transverse energy and one or two high energy jets. We compare the data
with the predictions from a -dimensional Kaluza-Klein scenario in which
gravity becomes strong at the TeV scale. At 95% confidence level (C.L.) for
=2, 4, and 6 we exclude an effective Planck scale below 1.0, 0.77, and 0.71
TeV, respectively.Comment: Submitted to PRL, 7 pages 4 figures/Revision includes 5 figure
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