590 research outputs found
Agricultural inventory capabilities of machine processed LANDSAT digital data
Agricultural crop identification and acreage determination analysis of LANDSAT digital data was performed for two study areas. A multispectral image processing and analysis system was utilized to perform the manmachine interactive analysis. The developed techniques yielded crop acreage estimate results with accuracy greater than 90% and as high as 99%. These results are encouraging evidence of agricultural inventory capabilities of machine processed LANDSAT digital data
Behavioral metabolution: the adaptive and evolutionary potential of metabolism-based chemotaxis
We use a minimal model of metabolism-based chemotaxis to show how a coupling between metabolism and behavior can affect evolutionary dynamics in a process we refer to as behavioral metabolution. This mutual influence can function as an in-the-moment, intrinsic evaluation of the adaptive value of a novel situation, such as an encounter with a compound that activates new metabolic pathways. Our model demonstrates how changes to metabolic pathways can lead to improvement of behavioral strategies, and conversely, how behavior can contribute to the exploration and fixation of new metabolic pathways. These examples indicate the potentially important role that the interplay between behavior and metabolism could have played in shaping adaptive evolution in early life and protolife. We argue that the processes illustrated by these models can be interpreted as an unorthodox instantiation of the principles of evolution by random variation and selective retention. We then discuss how the interaction between metabolism and behavior can facilitate evolution through (i) increasing exposure to environmental variation, (ii) making more likely the fixation of some beneficial metabolic pathways, (iii) providing a mechanism for in-the-moment adaptation to changes in the environment and to changes in the organization of the organism itself, and (iv) generating conditions that are conducive to speciatio
The results of using a tendon autograft as a new rotator cable for patients with a massive rotator cuff tear:a technical note and comparative outcome analysis
Background: Several surgical reconstructive options are available to treat massive rotator cuff tears (MRCTs). The rotator cable has an important function and we evaluated the clinical result after arthroscopic reconstruction of the rotator cable with an autograft tendon. Methods: A prospective pilot study was performed with inclusion of four patients, average age of 64 years, with an irreparable MRCT. The patients underwent an arthroscopic reconstruction of the rotator cable with the use of the long head of biceps tendon autograft, except for one which was reconstructed with a hamstring tendon. Pre- and postsurgically, the Constant-Murley Score (CMS), Western Ontario Rotator Cuff Index (WORC), Simple Shoulder Test (SST), visual analog scale (VAS) scores, and an MRI was performed. Clinical results of the study group were compared with clinical results of comparable cohort of patients with a MRCT, treated non-operatively with physiotherapy. Results: The CMS score increased after surgery in three of the four patients. The improvement of CMS score was comparable to the improvement of the CMS score encountered in a comparable cohort. The MRI at 12 months follow-up showed that the reconstructed rotator cable was disintegrated in all patients and the rotator cuff was detached and retracted. Conclusions: In our pilot study, arthroscopic reconstruction of the rotator cable using a tendon autograft failed over time and showed no clinical benefit in comparison to the non-operative treatment with physiotherapy. Trial registration: The regional Medical Ethical Committee (Zwolle) gave approval at 14th of October 2016 and assigned no. 16.06100
Using the Long Head of Biceps Tendon Autograft as an Anatomical Reconstruction of the Rotator Cable:An Arthroscopic Technique for Patients With Massive Rotator Cuff Tears
The treatment of massive rotator cuff tears (MRCT) is challenging. Insufficient tissue quality, size, and retraction of the cuff often lead to failures of repair. Different techniques like direct repair, partial repair, and graft applications have been developed, but results are not yet predictable. In this arthroscopic technique the objective is not to reconstruct the rotator cuff as a tissue layer but to restore the biomechanical function of the rotator cable with an autograft of the long head of the biceps tendon. After glenohumeral inspection, the long head of the biceps tendon is harvested and the retracted cuff is released and, if possible, closed partially side-to-side. The biceps graft is positioned from the posterior aspect of the greater tubercle to the superior part of the lesser tubercle and fixed with 2 biotenodesis anchors. Finally, the cuff remnants are securely sutured to the biceps graft with standard cuff repair sutures. This arthroscopic technique has several advantages because the biceps autograft is easily harvested, autologous, and rich in collagen. Previous studies show use of the biceps tendon differently for reconstruction of the rotator cuff, with promising results. Future studies are needed to evaluate clinical outcomes
Arthroscopic isolated long head of biceps tenotomy in patients with degenerative rotator cuff tears:mid-term clinical results and prognostic factors
INTRODUCTION: The long head of biceps tendon is frequently involved in degenerative rotator cuff tears. Therefore, this study explored the clinical results of an isolated biceps tenotomy and identified prognostic factors for improvement in pain and function. MATERIALS AND METHODS: Between 2008 and 2017, an arthroscopic isolated biceps tenotomy was performed on 64 patients with a degenerative rotator cuff tear (> 65 years). Primary outcome was patient-perceived improvement in pain and function. Potential prognostic factors for improvement in pain and function were identified. RESULTS: A perceived improvement in pain was reported in 78% of the patients at three months after surgery and in 75% at a mean follow-up of 4.2 years (1-7 years; n = 55). A perceived improvement in function was observed in 49% of patients at three months and in 76% of patients at follow-up. Patients with a preoperatively normal acromiohumeral distance (> 10 mm) reported an improvement in pain and function significantly more often. Retraction of the supraspinatus tendon Patte 3 was significantly associated with worse functional outcome. CONCLUSIONS: A biceps tenotomy can be a reliable treatment option for patients with symptomatic degenerative cuff tears who fail conservative treatment and have a normal acromiohumeral distance (> 10 mm)
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Variational assimilation of satellite observations in a coastal ocean model off Oregon
Satellite along-track sea surface height (SSH) and multisatellite sea surface temperature (SST) maps are assimilated in a coastal ocean circulation model off Oregon. The study period is June–October 2005, featuring intensive separation of the coastal upwelling jets in the eddy-dominated coastal transition zone (CTZ). The data assimilation (DA) system combines the nonlinear Regional Ocean Modeling System (ROMS) and the Advanced Variational Regional Ocean Representer Analyzer (AVRORA) tangent linear and adjoint codes developed by our group. The variational representer DA method is implemented in a series of 6 day time windows, with initial conditions corrected at the beginning of each window. To avoid the problem of matching the model and observed SSH mean levels, the observed SSH slope has been assimilated. Location, timing, and intensity of jets and eddies in the CTZ are constrained, to improve accuracy of nonlinear model analyses and forecasts. In the case assimilating SSH alone, the geometry of the SST front is improved. SSH assimilation results in the cross-shore transport more uniformly distributed along the coast than in the free run model. An outer front is identified in the DA analyses at a distance of 200 km from the coast. A strong subsurface horizontal temperature gradient across this front influences the depth of the thermocline in an area between the front and the continental slope. The DA correction term is comparable in magnitude to dominant terms in the volume-integrated heat equation. The time-averaged DA correction term in the volume-integrated heat balance is closer to 0 in the combined SSH-SST assimilation case, than in the case assimilating SSH alone.This is the publisher's final pdf. The published article is copyrighted by American Geophysical Union and can be found at: http://www.agu.org/journals/jc/index.shtm
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Spatial and Temporal Variability of the M2 Internal Tide Generation and Propagation on the Oregon Shelf
A 1-km-horizontal-resolution model based on the Regional Ocean Modeling System is implemented along the Oregon coast to study average characteristics and intermittency of the M₂ internal tide during summer upwelling. Wind-driven and tidally driven flows are simulated in combination, using realistic bathymetry, atmospheric forcing, and boundary conditions. The study period is April through August 2002, when mooring velocities are available for comparison. Modeled subtidal and tidal variability on the shelf are in good quantitative agreement with moored velocity time series observations. Depth-integrated baroclinic tidal energy flux (EF), its divergence, and topographic energy conversion (TEC) from the barotropic to baroclinic tide are computed from high-pass-filtered, harmonically analyzed model results in a series of 16-day time windows. Model results reveal several “hot spots” of intensive TEC on the slope. At these locations, TEC is well balanced by EF divergence. Changes in background stratification and currents associated with wind-driven upwelling and downwelling do not appreciably affect TEC hot spot locations but may affect intensity of internal tide generation at those locations. Relatively little internal tide is generated on the shelf. Areas of supercritical slope near the shelf break partially reflect baroclinic tidal energy to deeper water, contributing to spatial variability in seasonally averaged on-shelf EF. Despite significant temporal and spatial variability in the internal tide, the alongshore-integrated flux of internal tide energy onto the Oregon shelf, where it is dissipated, does not vary much with time. Approximately 65% of the M₂ baroclinic tidal energy generated on the slope is dissipated there, and the rest is radiated toward the shelf and interior ocean in roughly equal proportions. An experiment with smoother bathymetry reveals that slope-integrated TEC is more sensitive to bathymetric roughness than on-shelf EF.KEYWORDS: Continental shelf/slope, Tides, Internal waves, Hindcasts, North Pacific Ocean, Regional model
Torsion of the Gallbladder
A 77-year-old woman was seen with progressive abdominal pain. A CT scan was made and showed a large gallbladder extending into the right lower abdomen. Ultrasound was performed but demonstrated no gallstones. Laparoscopy showed a tordated, necrotic gallbladder that was attached to the liver only by the cystic artery and cystic duct. Cholecystectomy was performed. Torsion of the gallbladder is a rare but clinically important condition in which the diagnosis seldom is made preoperatively. In radiological and clinical signs of cholecystitis without gallstones, this condition should be considered
Cryo-EM structure of a tetrameric photosystem I from Chroococcidiopsis TS-821, a thermophilic, unicellular, non-heterocyst-forming cyanobacterium
Photosystem I (PSI) is one of two photosystems involved in oxygenic photosynthesis. PSI of cyanobacteria exists in monomeric, trimeric, and tetrameric forms, in contrast to the strictly monomeric form of PSI in plants and algae. The tetrameric organization raises questions about its structural, physiological, and evolutionary significance. Here we report the ∼3.72 Å resolution cryo-electron microscopy structure of tetrameric PSI from the thermophilic, unicellular cyanobacterium Chroococcidiopsis sp. TS-821. The structure resolves 44 subunits and 448 cofactor molecules. We conclude that the tetramer is arranged via two different interfaces resulting from a dimer-of-dimers organization. The localization of chlorophyll molecules permits an excitation energy pathway within and between adjacent monomers. Bioinformatics analysis reveals conserved regions in the PsaL subunit that correlate with the oligomeric state. Tetrameric PSI may function as a key evolutionary step between the trimeric and monomeric forms of PSI organization in photosynthetic organisms
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