215 research outputs found
Land Use Change and Policy in Iowa’s Loess Hills
We consider land use change in Iowa’s Loess Hills, which contain much of the state’s remaining prairie grassland. Although crop production has expanded on the landform since 2005, much of this expansion has been from soybean into corn with a clear trend toward more intensive corn rotations. Forest land has expanded in the area while we do not find evidence of extensive conversion to development. Data indicate that crop production has moved away from more heavily sloped land, but the increase in cropping does not appear to be occurring on land with high crop productivity
Land Use Change and Policy in Iowa’s Loess Hills
Land use changes have important implications on ecosystems and society. Detailed identification of the nature of land use changes in any local region is critical for policy design. In this paper, we quantify land use change in Iowa’s Loess Hills ecoregion, which contains much of the state’s remaining prairie grasslands. We employ two distinct panel datasets, the National Resource Inventory data and multi-year Cropland Data Layers, that allow us to characterize spatially-explicit land use change in the region over the period 1982-2010. We analyze land use trends, land use transitions and crop rotations within the ecoregion, and contrast these with county and state-level changes. To better comprehend the underlying land use changes, we evaluate our land use characterizing metrics conditional on soil quality variables such as slope and erodibility. We also consider the role of contemporary agricultural policy and commodity markets to seek explanations for land use changes during the period of our study. Although crop production has expanded on the Loess Hills landform since 2005, much of the expansion in corn acres has been from reduced soybean acreage. We find that out of the total 258 km2 increase in corn acreage during 2005-’10, about 100 km2 transitioned from soybeans. Data also indicate intensifying monoculture with higher percentage of corn plantings for two to four consecutive years during 2000-’10. In addition, crop production is found to have moved away from more heavily sloped land. Cropping does not appear to have increased on lands with higher crop productivity
Расчет ГИН по схеме Аркадьева-Маркса
Объектом исследования является генератор импульсного напряжения по схеме Аркадьева-Маркса. Цель работы: спроектировать и рассчитать генератор импульсных напряжений. В процессе работы рассчитаны количественные значения элементов ГИНа: значения коэффициентов использования разрядной схемы и волны; емкость и индуктивность конденсатора; количество ступеней; фронтовое и разрядное сопротивления. Был выполнен расчет ресурсов, ставки налогов, отчислений. Так же было описаны рабочее место и законодательные и нормативные документы.The object of study is the generator of pulse voltage according to the scheme Arkadiev-Marx. Objective: to design and calculate the voltage impulse generator. In the process, the calculated quantitative values of the elements of a Hin: the coefficients of use of the discharge circuit and wave; the capacitance and inductance of the capacitor; number of steps; the front and discharge resistors. Calculated resources, tax rates, deductions. As described workplace and legislative and regulatory documents
Characterizing Van Kampen Squares via Descent Data
Categories in which cocones satisfy certain exactness conditions w.r.t.
pullbacks are subject to current research activities in theoretical computer
science. Usually, exactness is expressed in terms of properties of the pullback
functor associated with the cocone. Even in the case of non-exactness,
researchers in model semantics and rewriting theory inquire an elementary
characterization of the image of this functor. In this paper we will
investigate this question in the special case where the cocone is a cospan,
i.e. part of a Van Kampen square. The use of Descent Data as the dominant
categorical tool yields two main results: A simple condition which
characterizes the reachable part of the above mentioned functor in terms of
liftings of involved equivalence relations and (as a consequence) a necessary
and sufficient condition for a pushout to be a Van Kampen square formulated in
a purely algebraic manner.Comment: In Proceedings ACCAT 2012, arXiv:1208.430
Comparing modern and presettlement forest dynamics of a subboreal wilderness: Does spruce budworm enhance fire risk?
Expanding the Repertoire of Natural Product-Inspired Ring Pairs for Molecular Recognition of DNA
A furan amino acid, inspired by the recently discovered proximicin natural products, was incorporated into the scaffold of a DNA-binding hairpin polyamide. While unpaired oligomers of 2,4-disubstituted furan amino acids show poor DNA-binding activity, furan (Fn) carboxamides paired with N-methylpyrrole (Py) and N-methylimidazole (Im) rings demonstrate excellent stabilization of duplex DNA as well as discrimination of noncognate sequences, consistent with function as a Py mimic according to the Py/Im polyamide pairing rules
Structure-Activity Relationship for the Oxadiazole Class of Antibiotics
The structure-activity relationship (SAR) for the newly discovered oxadiazole class of antibiotics is described with evaluation of 120 derivatives of the lead structure. This class of antibiotics was discovered by in silico docking and scoring against the crystal structure of a penicillin-binding protein. They impair cell-wall biosynthesis and exhibit activities against the Gram-positive bacterium Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA) and vancomycin-resistant and linezolid-resistant S. aureus. 5-(1H-Indol-5-yl)-3-(4-(4-(trifluoromethyl)phenoxy)phenyl)-1,2,4-oxadiazole (antibiotic 75b) was efficacious in a mouse model of MRSA infection, exhibiting a long half-life, a high volume of distribution, and low clearance. This antibiotic is bactericidal and is orally bioavailable in mice. This class of antibiotics holds great promise in recourse against infections by MRSA.Fil: Spink, Edward. University of Notre Dame-Indiana; Estados UnidosFil: Ding, Derong. University of Notre Dame-Indiana; Estados UnidosFil: Peng, Zhihong. University of Notre Dame-Indiana; Estados UnidosFil: Boudreau, Marc A.. University of Notre Dame-Indiana; Estados UnidosFil: Leemans, Erika. University of Notre Dame-Indiana; Estados UnidosFil: Lastochkin, Elena. University of Notre Dame-Indiana; Estados UnidosFil: Song, Wei. University of Notre Dame-Indiana; Estados UnidosFil: Lichtenwalter, Katerina. University of Notre Dame-Indiana; Estados UnidosFil: O’Daniel, Peter I.. University of Notre Dame-Indiana; Estados UnidosFil: Testero, Sebastian Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; Argentina. University of Notre Dame-Indiana; Estados UnidosFil: Pi, Hualiang. University of Notre Dame-Indiana; Estados UnidosFil: Schroeder, Valerie A.. University of Notre Dame-Indiana; Estados UnidosFil: Wolter, William R.. University of Notre Dame-Indiana; Estados UnidosFil: Antunes, Nuno T.. University of Notre Dame-Indiana; Estados UnidosFil: Suckow, Mark A.. University of Notre Dame-Indiana; Estados UnidosFil: Vakulenko, Sergei. University of Notre Dame-Indiana; Estados UnidosFil: Chang, Mayland. University of Notre Dame-Indiana; Estados UnidosFil: Mobashery, Shahriar. University of Notre Dame-Indiana; Estados Unido
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
- …