High-Resolution, Mobile Doppler Radar Observations of Cyclic Mesocyclogenesis in a Supercell

2008 ◽  
Vol 136 (12) ◽  
pp. 4997-5016 ◽  
Author(s):  
Michael M. French ◽  
Howard B. Bluestein ◽  
David C. Dowell ◽  
Louis J. Wicker ◽  
Matthew R. Kramar ◽  
...  
Keyword(s):  
High Resolution ◽  
Wind Shear ◽  
Doppler Radar ◽  
Cyclic Behavior ◽  
Vorticity Generation ◽  
The Mean ◽  
Multiple Levels ◽  
The Individual ◽  
Mean Circulation ◽  
Short Time

Abstract On 15 May 2003, two ground-based, mobile, Doppler radars scanned a supercell that moved through the Texas Panhandle and cyclically produced mesocyclones. The two radars collected data from the storm during a rapid cyclic mesocyclogenesis stage and a more slowly evolving tornadic period. A 3-cm-wavelength radar scanned the supercell continuously for a short time after it was cyclic but close to the time of tornadogenesis. A 5-cm-wavelength radar scanned the supercell the entire time it exhibited cyclic behavior and for an additional 30 min after that. The volumetric data obtained with the 5-cm-wavelength radar allowed for the individual circulations to be analyzed at multiple levels in the supercell. Most of the circulations that eventually dissipated moved rearward with respect to storm motion and were located at distances progressively farther away from the region of rear-flank outflow. The circulations associated with a tornado did not move nearly as far rearward relative to the storm. The mean circulation diameters were approximately 1–4 km and had lifetimes of 10–30 min. Circulation dissipation often, but not always, occurred following decreases in circulation diameter, while changes in maximum radial wind shear were not reliable indicators of circulation dissipation. In one instance, a pair of circulations rotated cyclonically around, and moved toward, each other; the two circulations then combined to form one circulation. Single-Doppler radial velocities from both radars were used to assess the differences between the pretornadic circulations and the tornadic circulations. Storm outflow in the rear flank of the storm increased notably during the time cyclic mesocyclogenesis slowed and tornado formation commenced. Large storm-relative inflow likely advected the pretornadic circulations rearward in the absence of organized outflow. The development of strong outflow in the rear flank probably balanced the strong inflow, allowing the tornadic circulations to stay in areas rich in vertical vorticity generation.

scholarly journals Wind Shear Effects on Radiatively and Evaporatively Driven Stratocumulus Tops

2018 ◽  
Vol 75 (9) ◽  
pp. 3245-3263 ◽  
Author(s):  
Bernhard Schulz ◽  
Juan Pedro Mellado
Keyword(s):  
Critical Velocity ◽  
Wind Shear ◽  
Radiative Cooling ◽  
Entrainment Rate ◽  
Entrainment Velocity ◽  
Velocity Jump ◽  
Individual Contributions ◽  
Shear Effects ◽  
The Mean ◽  
The Individual

Abstract Direct numerical simulations resolving meter and submeter scales in the cloud-top region of stratocumulus are used to investigate the interactions between a mean vertical wind shear and in-cloud turbulence driven by evaporative and radiative cooling. There are three major results. First, a critical velocity jump exists, above which shear significantly broadens the entrainment interfacial layer (EIL), enhances cloud-top cooling, and increases the mean entrainment velocity; shear effects are negligible when the velocity jump is below . Second, a depletion velocity jump exists, above which shear-enhanced mixing reduces cloud-top radiative cooling, thereby weakening the large convective motions; shear effects remain localized within the EIL when the velocity jump is below . The critical velocity jump and depletion velocity jump are provided as a function of in-cloud and free-tropospheric conditions, and one finds and for typical subtropical conditions. Third, the individual contributions to the mean entrainment velocity from mixing, radiative cooling, and evaporative cooling strongly depend on the choice of the reference height where the entrainment velocity is calculated. This result implies that the individual contributions to the mean entrainment velocity should be estimated at a comparable height while deriving entrainment-rate parameterizations. A strong shear alters substantially the magnitude and the height where these individual contributions reach their maxima, which further demonstrates the importance of shear on the dynamics of stratocumulus clouds.

scholarly journals Year-to-Year Reoutcropping of Eighteen Degree Water in an Eddy-Resolving Ocean Simulation

2015 ◽  
Vol 45 (4) ◽  
pp. 1189-1204 ◽  
Author(s):  
Young-Oh Kwon ◽  
Jong-Jin Park ◽  
Stefan F. Gary ◽  
M. Susan Lozier
Keyword(s):  
Surface Temperature ◽  
Time Scale ◽  
Sea Surface ◽  
Model Simulations ◽  
Temperature Anomalies ◽  
The Family ◽  
Sea Surface Temperature Anomalies ◽  
The Mean ◽  
The Individual ◽  
Mean Circulation

AbstractWinter outcropping of the Eighteen Degree Water (EDW) and its subsequent dispersion are studied using a ° eddy-resolving simulation of the Family of Linked Atlantic Modeling Experiments (FLAME). Outcropped EDW columns in the model simulations are detected in each winter from 1990 to 1999, and particles are deployed in the center of each outcropped EDW column. Subsequently, the trajectories of these particles are calculated for the following 5 yr. The particles slowly spread away from the outcropping region into the nonoutcropping/subducted EDW region south of ~30°N and eventually to the non-EDW region in the greater subtropical gyre. Approximately 30% of the particles are found in non-EDW waters 1 yr after deployment; after 5 yr, only 25% of the particles are found within EDW. The reoutcropping time is defined as the number of years between when a particle is originally deployed in an outcropping EDW column and when that particle is next found in an outcropping EDW column. Of the particles, 66% are found to reoutcrop as EDW in 1 yr, and less than 5% of the particles outcrop in each of the subsequent 4 yr. While the individual trajectories exhibit significant eddy-like motions, the time scale of reoutcropping is primarily set by the mean circulation. The dominance of reoutcropping in 1 yr suggests that EDW outcropping contributes considerably to the persistence of surface temperature anomalies from one winter to the next, that is, the reemergence of winter sea surface temperature anomalies.

scholarly journals Quantitative measurement of bubble textures in pumice clasts using a digital stereo microscope with low-angled ring illumination

2020 ◽  
Vol 72 (1) ◽  
Author(s):  
Masatoshi Ohashi ◽  
Mie Ichihara ◽  
Fukashi Maeno ◽  
Ben Kennedy ◽  
Darren Gravley
Keyword(s):  
Bubble Radius ◽  
Eruption Dynamics ◽  
Deformation Degree ◽  
Size And Shape ◽  
The Matrix ◽  
Stereo Microscope ◽  
The Mean ◽  
Distinctive Difference ◽  
The Individual ◽  
Short Time

AbstractQuantitative analysis of bubble textures in a large number of volcanic pyroclasts is critical to investigating the eruption dynamics in a volcanic conduit. Here, we used a digital stereo microscope with low-angled ring illumination (DSM-LaRI) to measure bubble textures on unpolished cutting surfaces of pumice clasts. As the DSM-LaRI enhances brightness contrast between the bubbles (pores) and the matrix, we easily obtained the two-dimensional data on the size and shape of bubbles by image analysis. The DSM-LaRI imaging provided the distributions of size and shape of bubbles at least 50 µm across. We applied the DSM-LaRI to analyze more than 1000 pumice clasts from the 232 AD Taupo eruption and measured the mean bubble radius ($$\overline{R}$$ R ¯ ) and the mean deformation degree ($$\overline{D}$$ D ¯ ) in the individual clasts. The distribution of $$\overline{R}$$ R ¯ and $$\overline{D}$$ D ¯ in each layer showed a distinctive difference between the fallout and the flow deposits. These quantitative data are consistent with a qualitative classification in a previous study. Although the new DSM-LaRI method has the disadvantage of the low spatial resolution, it allows for the analysis of a large number of pumice clasts in a short time, which can address larger scale heterogeneity, by efficiently generating a large representative suite of bubble size and shape data to link bubble textures to conduit processes. This provides vital information for quantitatively modeling eruption dynamics.

Algorithms for automated montage synthesis of images from laser-scanning confocal microscopes

1995 ◽  
Vol 53 ◽  
pp. 650-651
Author(s):  
D. E. Becker
Keyword(s):  
Image Analysis ◽  
High Resolution ◽  
Laser Scanning ◽  
Cell Counting ◽  
Wide Area ◽  
Data Set ◽  
Computational Synthesis ◽  
Automated Cell Counting ◽  
Partial View ◽  
The Individual

An efficient, robust, and widely-applicable technique is presented for computational synthesis of high-resolution, wide-area images of a specimen from a series of overlapping partial views. This technique can also be used to combine the results of various forms of image analysis, such as segmentation, automated cell counting, deblurring, and neuron tracing, to generate representations that are equivalent to processing the large wide-area image, rather than the individual partial views. This can be a first step towards quantitation of the higher-level tissue architecture. The computational approach overcomes mechanical limitations, such as hysterisis and backlash, of microscope stages. It also automates a procedure that is currently done manually. One application is the high-resolution visualization and/or quantitation of large batches of specimens that are much wider than the field of view of the microscope.The automated montage synthesis begins by computing a concise set of landmark points for each partial view. The type of landmarks used can vary greatly depending on the images of interest. In many cases, image analysis performed on each data set can provide useful landmarks. Even when no such “natural” landmarks are available, image processing can often provide useful landmarks.

A Simple Method for the Evaluation of Internal Doses in Nuclear Medicine

1974 ◽  
Vol 13 (02) ◽  
pp. 193-206
Author(s):  
L. Conte ◽  
L. Mombelli ◽  
A. Vanoli
Keyword(s):  
Nuclear Medicine ◽  
Close Agreement ◽  
Whole Body ◽  
Simple Method ◽  
Rapid Estimation ◽  
Absorbed Doses ◽  
The Mean ◽  
The Individual ◽  
Estimation Of Risk

SummaryWe have put forward a method to be used in the field of nuclear medicine, for calculating internally absorbed doses in patients. The simplicity and flexibility of this method allow one to make a rapid estimation of risk both to the individual and to the population. In order to calculate the absorbed doses we based our procedure on the concept of the mean absorbed fraction, taking into account anatomical and functional variability which is highly important in the calculation of internal doses in children. With this aim in mind we prepared tables which take into consideration anatomical differences and which permit the calculation of the mean absorbed doses in the whole body, in the organs accumulating radioactivity, in the gonads and in the marrow; all this for those radionuclides most widely used in nuclear medicine. By comparing our results with dose obtained from the use of M.I.R.D.'s method it can be seen that when the errors inherent in these types of calculation are taken into account, the results of both methods are in close agreement.

SERUM THYROTROPHIN AND THE RESPONSE TO THYROTROPHIN RELEASING HORMONE IN SYMPTOMLESS AUTOIMMUNE THYROIDITIS AND IN BORDERLINE AND OVERT HYPOTHYROIDISM

1974 ◽  
Vol 75 (2) ◽  
pp. 274-285 ◽  
Author(s):  
A. Gordin ◽  
P. Saarinen ◽  
R. Pelkonen ◽  
B.-A. Lamberg
Keyword(s):  
Autoimmune Thyroiditis ◽  
Elevated Serum ◽  
Mean Value ◽  
Primary Hypothyroidism ◽  
Overt Hypothyroidism ◽  
Thyrotrophin Releasing Hormone ◽  
Releasing Hormone ◽  
The Mean ◽  
The Individual ◽  
Serum Tsh

ABSTRACT Serum thyrotrophin (TSH) was determined by the double-antibody radioimmunoassay in 58 patients with primary hypothyroidism and was found to be elevated in all but 2 patients, one of whom had overt and one clinically borderline hypothyroidism. Six (29%) out of 21 subjects with symptomless autoimmune thyroiditis (SAT) had an elevated serum TSH level. There was little correlation between the severity of the disease and the serum TSH values in individual cases. However, the mean serum TSH value in overt hypothyroidism (93.4 μU/ml) was significantly higher than the mean value both in clinically borderline hypothyroidism (34.4 μU/ml) and in SAT (8.8 μU/ml). The response to the thyrotrophin-releasing hormone (TRH) was increased in all 39 patients with overt or borderline hypothyroidism and in 9 (43 %) of the 21 subjects with SAT. The individual TRH response in these two groups showed a marked overlap, but the mean response was significantly higher in overt (149.5 μU/ml) or clinically borderline hypothyroidism (99.9 μU/ml) than in SAT (35.3 μU/ml). Thus a normal basal TSH level in connection with a normal response to TRH excludes primary hypothyroidism, but nevertheless not all patients with elevated TSH values or increased responses to TRH are clinically hypothyroid.

Quality of Life for Children with Persistent Sinonasal Symptoms

2003 ◽  
Vol 128 (1) ◽  
pp. 17-26 ◽  
Author(s):  
David J. Kay ◽  
Richard M. Rosenfeld
Keyword(s):  
Quality Of Life ◽  
Clinical Care ◽  
Longitudinal Change ◽  
Good Test ◽  
Routine Clinical Care ◽  
Before And After ◽  
The Mean ◽  
The Individual ◽  
Sinonasal Symptoms

OBJECTIVE: The goal was to validate the SN-5 survey as a measure of longitudinal change in health-related quality of life (HRQoL) for children with persistent sinonasal symptoms. DESIGN AND SETTING: We conducted a before and after study of 85 children aged 2 to 12 years in a metropolitan pediatric otolaryngology practice. Caregivers completed the SN-5 survey at entry and at least 4 weeks later. The survey included 5 symptom-cluster items covering the domains of sinus infection, nasal obstruction, allergy symptoms, emotional distress, and activity limitations. RESULTS: Good test-retest reliability ( R = 0.70) was obtained for the overall SN-5 score and the individual survey items ( R ≥ 0.58). The mean baseline SN-5 score was 3.8 (SD, 1.0) of a maximum of 7.0, with higher scores indicating poorer HRQoL. All SN-5 items had adequate correlation ( R ≥ 0.36) with external constructs. The mean change in SN-5 score after routine clinical care was 0.88 (SD, 1.19) with an effect size of 0.74 indicating good responsiveness to longitudinal change. The change scores correlated appropriately with changes in related external constructs ( R ≥ 0.42). CONCLUSIONS: The SN-5 is a valid, reliable, and responsive measure of HRQoL for children with persistent sinonasal symptoms, suitable for use in outcomes studies and routine clinical care.

Flight speed, foraging efficiency, and daily energy budget of the Barn Swallow, Hirundo rustica

1997 ◽  
Vol 75 (7) ◽  
pp. 1176-1183 ◽  
Author(s):  
Horacio de la Cueva ◽  
Robert W. Blake
Keyword(s):  
Doppler Radar ◽  
Flight Speed ◽  
Hirundo Rustica ◽  
Foraging Efficiency ◽  
Barn Swallow ◽  
Aerodynamic Model ◽  
Daily Energy ◽  
Energy Store ◽  
The Mean ◽  
Barn Swallows

Aerodynamic power equations predict optimal speeds at which birds ought to fly if they are to maximize time spent in the air on a given energy store (minimum power speed, Vmp), distance covered using a given amount of fuel (maximum range speed, Vmr), and rate of delivering food to the chicks in the nest (Vnest), or maximize the daily energy balance (VDBAL). With the aerodynamic model employed, these speeds are 5.3, 7.0, 7.9, and 8.9 m∙s−1, respectively, for the Barn Swallow, Hirundo rustica. A comparison of the predicted flight speed with both the mean and median flight speeds (8 m∙s−1 in both cases; n = 821) recorded with Doppler radar indicates that Barn Swallows fly at speeds not significantly different from Vnest. The true sample size was unknown, and realistic sample sizes are drawn with bootstrap procedures and compared with those given by the number of measurements (821); no significant differences were found. To test the model, energy requirements for growth, prey density, and time spent foraging were varied independently in a sensitivity analysis. Large but realistic changes in these three variables do not contradict the model and predict speeds within the range measured in the field.

scholarly journals VARIABILITY OF EVOLUTIONARY RATES OF DNA

Genetics ◽  
1986 ◽  
Vol 113 (4) ◽  
pp. 1077-1091
Author(s):  
John H Gillespie
Keyword(s):  
Dna Sequences ◽  
Significant Excess ◽  
Ergodic Markov Chain ◽  
The Third ◽  
Markov Chain Models ◽  
Rate Of Molecular Evolution ◽  
The Mean ◽  
Nuclear Loci ◽  
The Individual ◽  
Evolution Of Proteins

ABSTRACT A statistical analysis of DNA sequences from four nuclear loci and five mitochondrial loci from different orders of mammals is described. A major aim of the study is to describe the variation in the rate of molecular evolution of proteins and DNA. A measure of rate variability is the statistic R, the ratio of the variance in the number of substitutions to the mean number. For proteins, R is found to be in the range 0.16 < R < 35.55, thus extending in both directions the values seen in previous studies. An analysis of codons shows that there is a highly significant excess of double substitutions in the first and second positions, but not in the second and third or first and third positions. The analysis of the dynamics of nucleotide evolution showed that the ergodic Markov chain models that are the basis of most published formulas for correcting for multiple substitutions are incompatible with the data. A bootstrap procedure was used to show that the evolution of the individual nucleotides, even the third positions, show the same variation in rates as seen in the proteins. It is argued that protein and silent DNA evolution are uncoupled, with the evolution at both levels showing patterns that are better explained by the action of natural selection than by neutrality. This conclusion is based primarily on a comparison of the nuclear and mitochondrial results.

scholarly journals AB0117 HLA B27*SUBTYPES FREQUENCIES IN COLOMBIAN PATIENTS WITH SPONDYLOARTHRITIS AND HEALTHY SUBJECTS TYPED IN HIGH-RESOLUTION TECHNIQUE

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 1358.1-1359
Author(s):  
C. Romero-Sánchez ◽  
W. Bautista-Molano ◽  
Y. M. Chamorro-Melo ◽  
A. Beltrán-Ostos ◽  
J. De Avila ◽  
...  
Keyword(s):  
High Resolution ◽  
Allelic Frequency ◽  
Male Gender ◽  
Inflammatory Back Pain ◽  
Genotypic Frequency ◽  
Hla B27 ◽  
Healthy Individuals ◽  
Current Smoking ◽  
Subtype B ◽  
The Mean

Background:HLA-B*27 has been identify as a susceptibility and prognostic factor associated to axial spondyloarthritis. HLA-B*27 allele has been described to be present in about 90% of patients with ankylosing spondylitis, and with a different frequency in patients with other subtypes of SpA. In contrast, this allele has been observed to be present only in 7–8% in general population. A remarkable heterogeneity in HLA-B*27 alleles has been reported. They have been determined at DNA sequence and some subtypes have been associated increasing the risk to develop the diseaseObjectives:To establish the frequencies of HLA-B27 subtypes in a group of Colombian patients with SpA and healthy populationMethods:In total, 61 Blood samples from Colombian mestizo individuals with SpA according to ASAS classification-criteria were evaluated by Sequencing Technology: Illumina Sequencing/PacBio Sequencing with analysis of the second and third exon. Results reported with six digits (including null alleles). In total, 294 results of peripheral blood from healthy individuals without joint symptoms were analyzed. Frequencies were obtained for demographic and genetic variables. Ethic Committee approval code 2018-020/2017-023Results:The SpA group had a mean age of 45,88 ± 11,67, 62.3% of them were male, 6.6% reported current smoking and 37.7% reported smoking sometime in life. In total, 67.2% had inflammatory back pain, 14.8% had dactylitis, 63.9% enthesitis and 57.4% arthritis. Thirty patients were HLA-B*27 positive with a genotypic frequency of 50.8% and an allelic frequency of 24.6%. In this group of patients, the mean age was 43,5 ± 11,8, 76.6% were male, 86.7% of them were subtype B*27:05:02g and 13.3% presented the B27:02:01g. None of the SpA patients had both B*27 alleles.On the other hand, the healthy individuals were men in 51.0% and the mean age was 37±15.4 years. Ten subjects were positive for the HLA-B*27 allele with a genotypic frequency of 3.4% and an allelic frequency of 1.7%. In this group of individuals 50.0% were male gender with a mean age of 38.4±17.9. No individuals were found to have the two alleles or homozygous for the B*27 allele. In all of them the subtype B*27:05:02g was observed in high-resolution sequencingConclusion:The SpA group had a mean age of 45,88 ± 11,67, 62.3% of them were male, 6.6% reported current smoking and 37.7% reported smoking sometime in life. In total, 67.2% had inflammatory back pain, 14.8% had dactylitis, 63.9% enthesitis and 57.4% arthritis. Thirty patients were HLA-B*27 positive with a genotypic frequency of 50.8% and an allelic frequency of 24.6%. In this group of patients, the mean age was 43,5 ± 11,8, 76.6% were male, 86.7% of them were subtype B*27:05:02g and 13.3% presented the B27:02:01g. None of the SpA patients had both B*27 alleles.On the other hand, the healthy individuals were men in 51.0% and the mean age was 37±15.4 years. Ten subjects were positive for the HLA-B*27 allele with a genotypic frequency of 3.4% and an allelic frequency of 1.7%. In this group of individuals 50.0% were male gender with a mean age of 38.4±17.9. No individuals were found to have the two alleles or homozygous for the B*27 allele. In all of them the subtype B*27:05:02g was observed in high-resolution sequencingAcknowledgments:Hospital Militar Central (Grant 2017-023/2018-020), the Government Institute of Science, Technology, and Innovation, Francisco Jose de Caldas—COLCIENCIAS (Grant No. 130877757442) and Colombian Rheumatology Association (Grant-Conv-2019)Disclosure of Interests:None declared

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