657 research outputs found
Structural Geology of the Caddo Gap Area, Ouachita Mountains, Arkansas
The Caddo Gap quadrangle is located on the southern margin of the Benton Uplift, the orogenic core of the Ouachita Mountains. Recent field mapping focused on delineating stratigraphic and structural relationships in the southern part of the quadrangle to improve existing reconnaissance-scale maps of the area. New structures were discovered that provide further information about the structural evolution of the Ouachita fold and thrust belt.
Field work included mapping the three informal members (Lower, Middle and Upper) of the Arkansas Novaculite. Major folds within the study area include the Nelson Mountain Anticline and two synclinal folds (âSouth Caddo Mountainâ and âArrowhead Mountainâ) where south-dipping Novaculite has been folded around very sharply in map view, resulting in a âfishhook.â The backthrust interpretation for Strawn Mountain (Haley et al., 2009) was found to be more structurally complex than previously proposed.
Analysis of the Nelson Mountain Anticline shows it is steeply inclined and gently plunging: the calculated mean axial plane (n = 104) is 276°, 78°SW (N84°W, 78°SW) and mean fold axis is 22°, 101° (22°, S79°E), similar to the reconnaissance-scale findings of Evansin (1976). Two fishhook folds, both located at the west ends of east-west ridges of Arkansas Novaculite, have similar geometries. The mean axial planes are 290°, 71°SW (N70°W, 71°SW) and 289°, 81°SW (N71°W, 81°SW) and average fold axes are 37°, 125° (37°, S55°E) and 40°, 117° (40°, S63°E).
Previously unmapped, northeast-trending strike-slip faults in the Arkansas Novaculite were discovered on the east-west âSouth Ridgeâ immediately south of and adjacent to the South Caddo Mountain fold. This style of faulting differs significantly from previous regional interpretations (Haley et al., 2009) which instead show South Caddo Mountain juxtaposed against the north side of the South Ridge by thrust faulting. Field mapping found no evidence for thrust faulting on South Caddo or Arrowhead Mountains.
An alternative hypothesis is that late-stage, northwest-directed compression formed left-lateral strike-slip tear faults that cut obliquely through the regional structures of the Caddo Mountains. This style of faulting better explains the fishhook drag folds and the strike-slip faults on the South Ridge, with Strawn Mountain backthrusts accommodating the northwest-directed compression on the north limb of the Nelson Mountain Anticline
Rotational Optimizers: Simple & Robust DNN Training
The training dynamics of modern deep neural networks depend on complex
interactions between the learning rate, weight decay, initialization, and other
hyperparameters. These interactions can give rise to Spherical Motion Dynamics
in scale-invariant layers (e.g., normalized layers), which converge to an
equilibrium state, where the weight norm and the expected rotational update
size are fixed. Our analysis of this equilibrium in AdamW, SGD with momentum,
and Lion provides new insights into the effects of different hyperparameters
and their interactions on the training process. We propose rotational variants
(RVs) of these optimizers that force the expected angular update size to match
the equilibrium value throughout training. This simplifies the training
dynamics by removing the transient phase corresponding to the convergence to an
equilibrium. Our rotational optimizers can match the performance of the
original variants, often with minimal or no tuning of the baseline
hyperparameters, showing that these transient phases are not needed.
Furthermore, we find that the rotational optimizers have a reduced need for
learning rate warmup and improve the optimization of poorly normalized
networks.Comment: 23 pages, 9 figure
Evaluation of interface quality in organ-cultured lamellar corneal transplants
Background: With increasing numbers of lamellar keratoplasties, eye banks are challenged to deliver precut lamellar donor tissue. In Europe, the most common technique of corneal storage is organ culture which requires a deswelling process before surgical processing. The aim of this study was to investigate the influence of different deswelling times on the cutting plane quality after microkeratome-assisted lamellar dissection.
Methods: Eight paired donor corneas (16 specimens) not suitable for transplantation were organ cultured under standard conditions at the Eye Bank of the Ludwig-Maximilians UniversitÀt, Munich, Germany. Pairs of corneal buttons were analyzed during the deswelling process in dextrane-containing medium. While one cornea was cut at an early time point during the deswelling process and put back into deswelling medium thereafter, the partner cornea was completely deswollen and dissected after 72 hours. Specimens were then further processed for scanning electron microscopy. Surface quality was assessed both digitally using Scanning Probe Imaging Processing software, and manually by three blinded graders.
Results: The corneal buttons processed at the beginning of the deswelling process had a smoother surface when compared to the partner cornea that was cut at the end of the deswelling process. In our setting, no relevant difference was detectable between manual and automated microkeratome dissection.
Conclusion: For lamellar keratoplasty, organ-cultured corneas should be processed at an early stage during the deswelling process. We interpret the smoother dissection plane during early deswelling as a result of mechanical properties in a highly hydrated cornea
Active fluid de-resuscitation in critically ill patients with septic shock: A systematic review and meta-analysis.
PURPOSE
To evaluate the impact of active fluid de-resuscitation on mortality in critically ill patients with septic shock.
METHODS
A systematic search was performed on PubMed, EmBase, and the Cochrane Library databases. Trials investigating active fluid de-resuscitation and reporting data on mortality in patients with septic shock were eligible. The primary objective was the impact of active de-resuscitation in patients with septic shock on short-term mortality. Secondary outcomes were whether de-resuscitation lead to a fluid separation, and the impact of de-resuscitation on patient-centred outcomes.
RESULTS
Thirteen trials (8,030 patients) were included in the systematic review, whereof 5 randomised-controlled trials (RCTs) were included in the meta-analysis. None of the RCTs showed a reduction in mortality with active de-resuscitation measures (relative risk (RR) 1.12 [95%-CI 0.84 - 1.48]). Fluid separation was achieved by two RCTs. Evidence from non-randomised trials suggests a mortality benefit with de-resuscitation strategies and indicates a trend towards a more negative fluid balance. Patient-centred outcomes were not influenced in the RCTs, and only one non-randomised trial revealed an impact on the duration of mechanical ventilation and renal replacement requirement (RRT).
CONCLUSION
We found no evidence for superiority of active fluid de-resuscitation compared to usual care regarding mortality, fluid balance or patient-centred outcomes in patients with septic shock. Current evidence is limited by the lack of high-quality RCTs in patients with septic shock, the small sample sizes and the heterogeneity of the applied de-resuscitation techniques. In addition, validity of the majority of RCTs is compromised by their inability to achieve fluid separation
Ischemic preconditioning attenuates portal venous plasma concentrations of purines following warm liver ischemia in man
Background/Aims: Degradation of adenine nucleotides to adenosine has been suggested to play a critical role in ischemic preconditioning (IPC). Thus, we questioned in patients undergoing partial hepatectomy whether (i) IPC will increase plasma purine catabolites and whether (ii) formation of purines in response to vascular clamping (Pringle maneuver) can be attenuated by prior IPC. Methods: 75 patients were randomly assigned to three groups: group I underwent hepatectomy without vascular clamping; group II was subjected to the Pringle maneuver during resection, and group III was preconditioned (10 min ischemia and 10 min reperfusion) prior to the Pringle maneuver for resection. Central, portal venous and arterial plasma concentrations of adenosine, inosine, hypoxanthine and xanthine were determined by high-performance liquid chromatography. Results: Duration of the Pringle maneuver did not differ between patients with or without IPC. Surgery without vascular clamping had only a minor effect on plasma purine transiently increased. After the Pringle maneuver alone, purine plasma concentrations were most increased. This strong rise in plasma purines caused by the Pringle maneuver, however, was significantly attenuated by IPC. When portal venous minus arterial concentration difference was calculated for inosine or hypoxanthine, the respective differences became positive in patients subjected to the Pringle maneuver and were completely prevented by preconditioning. Conclusion: These data demonstrate that (i) IPC increases formation of adenosine, and that (ii) the unwanted degradation of adenine nucleotides to purines caused by the Pringle maneuver can be attenuated by IPC. Because IPC also induces a decrease of portal venous minus arterial purine plasma concentration differences, IPC might possibly decrease disturbances in the energy metabolism in the intestine as well. Copyright (C) 2005 S. Karger AG, Basel
Genomewide homozygosity mapping and molecular analysis of a candidate gene located on 22q13 (fibulin-1) in a previously undescribed vitreoretinal dystrophy
OBJECTIVES
To localize the gene that causes an autosomal recessively inherited vitreoretinal dystrophy that has not been described, to our knowledge, and to analyze a candidate gene mapped to 22q13 (fibulin-1 [FBLN1]).
METHODS
Homozygosity mapping with 500 microsatellite markers spread over the whole genome (mean distance, 7.2 centimorgans [cM]) and mutation analysis of the complete coding region of FBLN1.
RESULTS
Homozygosity for all analyzed markers was found in the 4 affected siblings in a region on chromosome 22 encompassing 12 cM from D22S444 (centromeric) to D22S1170 (telomeric). Lod scores were between 0.017 and 2.36 (theta = 0). A mutation analysis of the complete coding region of FBLN1, which encodes interacting extracellular matrix proteins, revealed 4 previously undescribed single nucleotide polymorphisms.
CONCLUSIONS
A genomewide homozygosity mapping analysis supported the hypothesis that the gene responsible for a unique vitreoretinal dystrophy is located on chromosome 22q13. No obviously pathogenic mutation was found in the candidate gene, FBLN1
Effects of climate change on reproduction,larval development, and adult health of coral trout (Plectropomus spp.)
Climate change is emerging as the single greatest threat to coral-reef ecosystems.The most immediate impacts will be a loss of diversity and changes to fish community composition and may lead to eventual declines in abundance and productivity of key fisheries species. A key component of this research is to assess effects of projected changes in environmental conditions (temperature and ocean acidity) due to climate change on reproduction, growth and development of coral trout (Plectropomus leopardis).Ultimately, this research will fill key knowledge gaps about climate change impacts on larger fishes, which are fundamental to optimizing resilience-based management, and in turn improve the adaptive capacity of industries and communities along the Great Barrier Reef
ZĂŒchtung auf Resistenz gegen Anthraknose bei Weisser Lupine
1. Hintergrund
2. Lupinen: Potential und Probleme
3. Anthraknose bei Lupinen
4. ResistenzzĂŒchtung: Stand international
5. FiBL â Lupinenprojekt: Ziele, Massnahmen, erste Ergebnisse, Ausblic
New Plant breeding Techniques and Organic Farming: scientific, regulatory and consumer issues
The LIVESEED project (Improving the performance and competitiveness of the organic sector by boosting organic seed and plant breeding efforts) will present & discuss the scientific controversies and the regulatory issues related to New Plant Breeding Techniques (NPBTs) as well as the results of a European survey on consumers attitudes and preferences on NPBTs in organic farming
Reduzierte Bodenbearbeitung - Deutliche Vorteile fĂŒr Bodenfruchtbarkeit
Eine reduzierte Bodenbearbeitung im Biolandbau bringt deutliche Vorteile in Bezug auf die Bodenfruchtbarkeit sowie teils höhere ErtrĂ€ge als beim Einsatz des Pflugs. Das zeigen erste Ergebnisse des FiBL-Forschungsprojekts âKlimaneutraler Acker- und GemĂŒsebauâ
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