3,098 research outputs found
Response of Fishes to Revetment Placement
Routine fish sampling with hoop nets was conducted monthly from April through December 1978 along natural and revetted riverbanks on the lower Mississippi River near Eudora, Arkansas, to monitor changes in fish populations affected by placement of new revetment for bank protection. Eighteen species of fish were collected with four species comprising over 75% of the total catch. During the months prior to revetment placement, freshwater drum, Aplodinotus grunniens, was the most abundant (32.7% of the catch) species collected. Following in abundance were the flathead catfish, Pylodictis olivaris, (9.8%), common carp, Cyprinus carpio, (7.8%), and blue catfish, Ictalurus furcatus, (3.3%). After revetment placement in August 1978, the freshwater drum was again the most abundant component, comprising 9.7% of the catch. Gizzard shad, Dorosoma cepedianum, flathead catfish, and blue catfish followed in abundance and comprised 8.9, 4.1, and 3.4% of the total catch, respectively. Catch per effort data indicated that fish were generally more abundant at natural bank stations than revetted bank stations but the difference was not significant. The study suggests that fish inhabiting natural riverbank habitat recover quite rapidly from bank perturbation caused by the placement of revetment
The preparation, identification and properties of chlorophyll derivatives
In the investigation of 10-hydroxy chlorophylls a and b novel techniques included modification of chromatography and the use of fully-deuterated compounds isolated from fully-deuterated autotropic algae to determine the molecular structure of the chlorophylls
Biogeographic Barriers in the Andes: Is the Amotape—Huancabamba Zone a Dispersal Barrier for Dry Forest Plants?
This is the final version of the article. Available from Missouri Botanical Garden Press via the DOI in this record.We investigate whether the Amotape—Huancabamba zone in the Andes acts as a barrier or corridor for plant species migration. We test this hypothesis based on data on trees, shrubs, and herbs collected in dry inter-Andean valleys (DIAVs) of Ecuador. We found that 72% of the species cross the Amotape—Huancabamba zone in a north—south direction and 13% of the species cross the Andes in an east—west direction. Southern DIAVs concentrate the highest numbers of endemic species. At the regional level we found that 43% of the species are exclusively Andean, while the remaining 57% are found in the Pacific lowlands, the Caribbean, and Mesoamerica. These results showing many species crossing the Amotape—Huancabamba zone in a north—south direction and also frequently found in neighboring lowland and highland ecosystems suggest that the Amotape—Huancabamba zone acts as a corridor for species migration of dry inter-Andean flora.This research was funded by the
SENESCYT scholarship “Convocatoria 2011,” the Oticon Foundation, Pontificia Universidad Catolica del Ecuador, and
SYNTHESYS research visiting grant 201
Acoustic Waveform Logging - Advances In Theory And Application
Full-waveform acoustic logging has made significant advances in both theory and application in recent years, and these advances have greatly increased the capability of log analysts to measure the physical properties of formations. Advances in theory provide
the analytical tools required to understand the properties of measured seismic waves,
and to relate those properties to such quantities as shear and compressional velocity and
attenuation, and primary and fracture porosity and permeability of potential reservoir
rocks. The theory demonstrates that all parts of recorded waveforms are related to
various modes of propagation, even in the case of dipole and quadrupole source logging.
However, the theory also indicates that these mode properties can be used to design
velocity and attenuation picking schemes, and shows how source frequency spectra can
be selected to optimize results in specific applications. Synthetic microseismogram computations are an effective tool in waveform interpretation theory; they demonstrate how shear arrival picks and mode attenuation can be used to compute shear velocity and
intrinsic attenuation, and formation permeability for monopole, dipole and quadrupole
sources. Array processing of multi-receiver data offers the opportunity to apply even
more sophisticated analysis techniques. Synthetic microseismogram data is used to illustrate the application of the maximum-likelihood method, semblance cross-correlation,
and Prony's method analysis techniques to determine seismic velocities and attenuations. The interpretation of acoustic waveform logs is illustrated by reviews of various
practical applications, including synthetic seismogram generation, lithology determination, estimation of geomechanical properties in situ, permeability estimation, and design of hydraulic fracture operations
Molecular orientational dynamics of the endohedral fullerene ScN@C as probed by C and Sc NMR
We measure 13C and 45Sc NMR lineshapes and spin-lattice relaxation times (T1)
to probe the orientational dynamics of the endohedral metallofullerene
Sc3N@C80. The measurements show an activated behavior for molecular
reorientations over the full temperature range with a similar behavior for the
temperature dependence of the 13C and 45Sc data. Combined with spectral data
from Magic Angle Spinning (MAS) NMR, the measurements can be interpreted to
mean the motion of the encapsulated Sc3N molecule is independent of that of the
C80 cage, although this requires the similar temperature dependence of the 13C
and 45Sc spin-lattice relaxation times to be coincidental. For the Sc3N to be
fixed to the C80 cage, one must overcome the symmetry breaking effect this has
on the Sc3N@C80 system since this would result in more than the observed two
13C lines.Comment: 6 pages, 5 figure
T-helper cell polarisation following severe polytrauma
Introduction
Severe polytrauma induces an immunosuppressive response and is associated with a very high incidence of nosocomial infections. Previous studies have inferred that this detrimental immune response results from polarisation of the T helper (Th) response towards an anti-inflammatory, TH2 dominated, response at the expense of a bactericidal, Th1 response [1].
Objectives
1) To define alterations in TH cell subsets following severe blunt polytrauma.
Methods
Patients presenting to the emergency department within 2 hours of severe polytrauma were eligible if intubated either at the scene or in ED. Isolated head injuries and those not expected to survive 24 hours were excluded. EDTA anti-coagulated blood was drawn at 0hr (within 2 hours of injury), at 24 and 72hrs. Samples were immediately lysed, washed, stained and analysed using a standardised human 8-colour TH 1, 2 & 17 panel [2] on an LSR II flow cytometer. A paired white cell count differential was obtained at each sampling point. Patients were followed until discharge or death. Data were analysed using non-parametric statistics, with results presented as median and IQR.
Results
15 consecutive severe polytrauma patients requiring Intensive Care Unit (ICU) admission were recruited. Demographic and clinical data are outlined in Figure 1. Twelve (80%) lymphocytosis (3.3x109/L, 2.5 - 4.4x109/L) (Figyre 2A). At 72 hours leukocytes had fallen (P < 0.01, figure 2A) such that 6 (54%) of those surviving were lymphopenic (0.9x109/L, 0.6 - 1.2x109/L). Circulating CD4+ (P = 0.01; Figure 2B) and CD4+CD25+ (P < 0.05) lymphocytes increased over 72 hours. When expressed as a percentage of total circulating lymphocytes no significant change in the proportions of the TH 1, 2 & 17 subpopulations was detected (Figure 2C-E).
Conclusions
Severe polytrauma patients swiftly become lymphopenic. Although a failure to normalise this during the ICU stay correlates with higher mortality [3] our study of TH cell subtypes demonstrates no evidence of a switch to a detrimental anti-inflammatory TH2 subtype at the expense of the potentially protective bactericidal TH1 subtype
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Distributed fibre optic sensors for measuring strain and temperature of cast-in-situ concrete test piles
In this paper we present the use of distributed fibre optic sensor (DFOS) technology to measure the temperature and strain of reinforced concrete test piles during construction and during static load tests. Eight test piles were recently instrumented with DFOS, on three construction sites in London, by the Cambridge Centre for Smart Infrastructure and Construction (CSIC), in collaboration with Ove Arup & Partners Ltd. The concrete curing temperature profiles of the piles were used to detect the presence of significant defects in the piles. The load test strain profiles along the length of the piles were used to determine the load capacity of the piles and estimate the design parameters of the various soil strata, as well as the internal relative displacement of the piles under various loads. Being distributed in nature, DFOS give a much more detailed picture of the performance of a test pile, as compared to traditional embedded point sensors, such as vibrating wire strain gauges and extensometers. This is demonstrated with a sample of data obtained from one of the instrumented test piles.This is the author accepted manuscript. It is currently under an indefinite embargo pending publication by ICE Publishing
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