bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermodynamic Limitations of Ice Accretion Instruments
Authors: Fraser D. , Rush C. K. , Baxter D. 
Published: August 2018

A number of instruments used for determining the supercooled water content of an icing cloud depend on measuring the rate of accretion of ice on an unheated body. It has been shown by Ludlam that, since only part of the supercooled water freezes on impact, and the rest cannot always be frozen by the limited convective and evaporative heat losses which are available, there are limiting water contents beyond which such methods of measurement are unreliable. These limits have been calculated for a rotating cylinder at normal and high flight speeds, and the results show that rotating cylinder measurements are of limited usefulness and may, in fact, prove entirely misleading as regards both water content and droplet size. Experimental results show agreement with the calculated values. The limits for a conventional rotating-disc rate-of-icing meter and for an NAE-Smith ice detector head have also been obtained experimentally.
It is concluded that apart from the possibility of using refrigerated ice-accretion instruments, it is necessary to use a thermal method of measuring high values of water concentration, but that an ice-accretion method must also be employed to distinguish between warm water, supercooled water and ice crystals.
Meteorological Problems in Forecasting Mountain Waves*
Authors: Colson DeVer 
Published: August 2018

The standing-wave development to the lee of prominent mountain ridges presents not only an interesting meteorological phenomenon but also a definite hazard to certain aircraft operations.
An analysis of the mountain-wave observations in the Sierras indicates the presence of strong winds normal to the mountain range as well as large vertical wind shears; and an inversion or at least a stable layer near the level of the mountain crest. Changes in the pressure and temperature patterns at both the surface and 500-mb level are shown for two examples of more intense wave developments. Also, mean surface and upper-level pressure and temperature patterns are shown for the strong-wave days. The association between these mean patterns and surface frontal movements, upper-level troughs, strong temperature gradients, and the jet stream are discussed. An example of the effect of wind shear and static stability is shown using equations and methods developed by Scorer.
Data on the occurrence of mountain-wave activity in other mountainous areas of the West are now being collected. Two examples of these results are shown.
An Evaluation of Some Condensation Trail Observations
Authors: Dunning Hal H. , La Seur N. E. 
Published: August 2018

Observations made on ten routine B-47 training missions are used to evaluate present theoretical work on formation of exhaust condensation trails, and these observations are then correlated with the structure of the upper troposphere and lower stratosphere, to determine synoptic features typically associated with favorable and unfavorable conditions for trail formation
For the altitudes considered broad areas of trail formation were found to occur only between the polar front and the sub-tropical jet streams. Broad areas unfavorable to trail formation were found to be located on the cyclonic shear side of the polar front jet and on the anticyclonic shear side of the subtropical jet. Agreement between these observations and theory is good.
Wind Stress on Water Surfaces
Authors: Neumann Gerhard 
Published: August 2018

Various attempts to estimate the total wind stress at the sea surface are briefly reviewed, and the difficulties in the application of the methods used in the past are discussed.
The results obtained under natural conditions, that is over larger bodies of water, such as the open sea or large lakes, agree fairly well with each other, whereas great discrepancies are observed with wind tunnel experiments. It is conceivable that the stress values obtained from wind tunnel experiments only hold for the special conditions encountered with small scale flow models. The most important hydrodynamical differences in the flow at both sides of the air-sea interfaces between small scale models and large scale natural bodies of water are pointed out.
Outer Precipitation Bands of Hurricanes Edna and Ione
Authors: Kessler Edwin 
Published: August 2018

Hurricanes Edna, 1954, and Ione, 1955 were observed by radar at South Truro, Massachusetts. Both storms are associated with convective shower bands near the northern extremities of their circulations. Shower characteristics in the two cases are virtually identical in most respects, but the bands which they comprise propagate in grossly dissimilar ways. The differences are attributed to the presence of a convergence line or zone (cold front) at the boundary between two large scale air streams in the case of Ione, and the absence of a corresponding feature in the case of Edna.
The Ione observations are in general accord with the Bjerknes cold frontal model, as recently modified by Sanders, in which warm air is entrained into the frontal zone and converges and rises there and above it. While the showers thereby formed move with the warm air in which they are embedded, the convergence zone moves with the winds northwest of the wind shift line. The Edna showers develop in an almost horizontally homogeneous wind field, and there is some question as to the persistence of the small scale lines of convergence which produce them.
This note also contains some brief discussion of banded structures associated with altostratus clouds and rain which occur in the outskirts of both Edna and Ione.
Diurnal and Other Fluctuations in Atmospheric Radioactivity of Natural Origin
Authors: Delwiche C. C. , Stout P. R. 
Published: August 2018

The radioactivity of the atmosphere resulting from natural sources has been monitored continuously for a period of two years. The method consists of collecting on moving strips of filter paper the daughter products of radon and thoron decay—principally Pb212 and Pb214. The highest activities found were 5 × 10−13 curies per liter of atmosphere and the lowest values in the order of 10−14 curies per liter. Changes in radioactivity may take place very rapidly so that a very high value may fall to one of the low values within an hour or less. Recent history of the air mass being sampled determines its content of these radioactive isotopes of natural origin. Maximal values are always characterized by still air held over land. Minimal values have been associated with air masses having been held over the sea where replenishment of radon is much reduced. The turbulence of winds causes mixing of radon with greater masses of air with correspondingly diluted levels of radioactivity.
In spite of the high degree of variability in atmospheric radioactivity from day to day or even from hour to hour, averages of the mean hourly activities when taken over a year in Berkeley, California show a well defined diurnal fluctuation. In this respect, data for 1955 are very close to those for the year 1956. On the yearly average, maximum activity occurs at 6 a.m. and minimum activity at 6 p.m. The averaged radioactivity of the atmosphere in the morning is about 40 per cent greater than the activity in the evening. This difference is probably a reflection of the tendency for offshore winds to migrate inland during the afternoon hours.
Samplings of stagnant air in wells and caves showed very high activity as compared to the open atmosphere. As much as 10−10 curies per liter of air have been observed in enclosed atmospheres.
Long-Range Weather Forecasting in the Soviet Union
Authors: Baum Werner A. , Thompson Philip D. 
Published: August 2018

Soviet developments in long-range weather forecasting are described and evaluated. Part I (by W. A. Baum), dealing with non-dynamical methods, is based entirely on a literature survey. Part II (by P. D. Thompson), dealing with dynamical methods, is based partially on direct contact with Russian colleagues.
Operational forecasts based upon the synoptic-empirical Multanovsky method, as modified during the last generation, appear to have been unsuccessful. This apparent failure, only very recently admitted, seems to stem in part from an almost blind adherence to the complex and somewhat mystical Multanovsky philosophy. There are definite indications that a sharp break with the past took place in the mid-fifties, but it is too soon to discern a clear trend or to estimate the impact of this break on operational capabilities. No attempts appear to have been made to apply modern statistical approaches to the problem.
Soviet understanding of the basic theory of dynamical long-range prediction does not seem to surpass ours. However, Russian meteorologists have been relatively forward-looking in the application of dynamical methods on an experimental or routine basis. Forecasts of surface mean monthly temperature anomalies, for the Eurasian continent, have been prepared by dynamical methods since 1952. Their accuracy appears not significantly different from that of subjective forecasts.
Regular Motions in the Ionosphere: Electric and Magnetic Relationships
Authors: Chapman Sydney 
Published: August 2018

Regular worldwide motions in the ionosphere produce daily varying currents there by dynamo action in association with the geomagnetic field. The changing field of these currents induces electric currents within the earth. At the earth's surface, the combined magnetic field of these currents is measured. The parts of primary and secondary origin can be determined separately. The form and intensity of the ionospheric currents can be found. Their height is inferred from the study of the ionospheric electron density and conductivity; it can also be measured by rockets.
The daily varying airflow in the layer bearing the electric current, at heights from about 90 to 125 km, can to some extent be inferred. The motion is due partly to the sun's thermal and tidal action and partly to the moon's tidal action. Many aspects of the magnetic variations and the inferred ionospheric motions are considered in some detail, especially their seasonal and sunspot-cycle changes and their variations from day to day.
Physical Methods and Instruments for Characterizing Hailstones
Authors: List Roland 
Published: August 2018

All methods and instruments currently being used for the physical characterization of hailstones are listed and discussed. Apart from the simpler measurements of diameter, shape, roughness, surface temperature, etc., particular attention is paid to the aerodynamic forces acting on free-falling hailstones and to the way these forces are ascertained. Further paragraphs are devoted to the technique for obtaining thin sections and to their importance in explaining the growth of ice particles. The application of calorimeters and separators in demonstrating the presence of liquid water in the hailstones is also discussed.
All these methods can be used for investigating artificially produced ice particles.
A Tornado-Producing Cloud Pattern Seen from Tiros I1
Authors: Whitney Linwood F. , Fritz Sigmund 
Published: August 2018

A small, bright, isolated cloud mass was observed by TIROS I over the Central Plains near an area of known tornado activity. The rectification of the TIROS picture is shown; the meteorological situation is presented; and a comparison of the picture content is made with the synoptic events. Evidence is presented indicating that (1) the first intense convective activity was associated with the isolated cloud mass in the picture, (2) the cloud mass was located in an area possessing characteristics found in tornado development situations, and (3) the cloud mass later expanded and spread northeastward spawning hail and tornadoes in central Oklahoma.
Several other significant features were seen in the satellite picture; included among these was a prominent boundary separating a very dark area from a somewhat brighter area. This boundary corresponded to a dewpoint “front” or strong moisture gradient separating very dry air from moister air.
Simulation Studies Related to GARP
Authors: Jastrow Robert , Halem Milton 
Published: August 2018

A series of simulation studies has been conducted in an effort to obtain information relevant to the planning of the First GARP Global Experiment. Thus far, the studies have used only the Mintz-Arakawa 1969 model, and have been concerned mainly with the utilization of IR vertical sounding measurements. The initial results indicate that temperature profiles derived from these measurements can play a valuable role, provided they are used on a continuing, day-to-day basis over an extended period. Temperature data used in this way appear to have a controlling influence on all other meteorological variables in the model, including winds and pressure in particular. Assuming a mean error of 1C in the temperature data, and assuming the coverage provided by the planned GARP satellite configuration of two polar orbiting satellites containing IR sounders with full side-scan capability, the experiments indicate that winds are determined within an error of 2 m sec−1 and pressures within an error of 2 mb. The wind and pressure determinations are significantly improved if (i) IR sounders are added to the geostationary satellites, (ii) the number of polar orbiting satellites is increased, or (iii) the errors in the temperature data are decreased. If the side-scan capability is reduced, the wind and pressure determinations are substantially worsened, and may fail entirely. The validity of these results is limited by (i) the defects of the model, especially in the tropics, (ii) the use of simulated data in place of real observations, and (iii) the fact that the experiments use a comparison with the solutions to the model as a test of the accuracy of the results, in place of a comparison with actual observations of winds and pressures.
A second series of experiments has been concerned with the relationship between the error limits specified in the global observations and the accuracy of the forecasts that will be based on these observations. The results indicate that with the present GARP data specifications, i.e., ± 3 m sec−1 in winds, ± 1C in temperature, and ± 3 mb in pressure, the forecasts begin to deteriorate on the 5th day and are misleading in major respects after the 8th day. The limit of deterministic predictability is reached in three weeks in agreement with the results of other studies. Further experiments indicate that the accuracy of the forecasts is limited primarily by the errors in the wind components, and secondarily by pressure errors. If the error limits are tightened to 1.5 m sec−1 in winds and to 2 mb in pressure, the forecasts are accurate in all major respects for 7 or 8 days. In order to secure accurate forecasts for 12 to 14 days, the error limits must be tightened to 0.5 m sec−1, 0.5 mb and 0.5C. In all cases, the limit of deterministic predictability is two or three times greater than the range of accurate forecasts.
Systematic Review and Meta‐analysis of SNPs from Genome‐Wide Association Studies of Head and Neck Cancer
Authors: Vukovic Vladimir , Stojanovic Jovana , Vecchioni Alessia , Pastorino Roberta , Boccia Stefania 
Published: August 2018

ObjectiveVarious genome‐wide association studies (GWASs) identified new head and neck cancer (HNC) susceptibility loci, although the evidence has not been systematically summarized. We performed a systematic review and meta‐analyses of the GWASs to identify the most commonly reported genetic loci associated with a risk of HNC.Data SourcesWe searched the PubMed, ISI Web of Science, SCOPUS, and GWAS databases to retrieve eligible studies, in English or Italian, published until June 1, 2017.Review MethodsOnly GWASs reporting data on the association between single‐nucleotide polymorphisms (SNPs) and HNC were included. The quality of included studies was evaluated using the Q‐Genie tool. Random‐effect meta‐analyses were performed considering only SNPs with at least 1 significant result from the included articles, and pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated.ResultsSeven studies of case‐control design were included in the review. Five studies on nasopharyngeal cancer (NPC) in Chinese, reporting on 27 different SNPs, were included in meta‐analyses. Results show that 6 SNPs (rs2076483, rs2975042, rs9258122, rs29232, and rs9510787) had an increased pooled estimates for A risk alleles (OR [95% CI]: 1.55 [1.36‐1.77], 1.90 [1.69‐2.14], 1.47 [1.31‐1.65], 1.52 [1.32‐1.76], and 1.22 [1.13‐1.31], respectively) while G risk allele of rs3129055 reported an OR of 1.49 (95% CI, 1.33‐1.67).ConclusionOur systematic review identified 5 SNPs located on chromosome 6 (rs2076483, rs2975042, rs3129055, rs9258122, and rs29232) and 1 (rs9510787) on chromosome 13 as significantly associated with an increased risk of NPC in Chinese.
Risk Factors for Posttracheostomy Tracheal Stenosis
Authors: Li Michael , Yiu Yin , Merrill Tyler , Yildiz Vedat , deSilva Brad , Matrka Laura 
Published: August 2018

ObjectiveTo determine the incidence of posttracheostomy tracheal stenosis and to investigate variables related to the patient, hospitalization, or operation that may affect stenosis rates.Study DesignA combined retrospective cohort and case‐control study.SettingTertiary care academic medical center.Subjects and MethodsA total of 1656 patients who underwent tracheostomy at a tertiary care medical center from January 2011 to November 2016 were reviewed for evidence of subsequent tracheal stenosis on airway endoscopy or computed tomography. Forty‐three confirmed cases of posttracheostomy tracheal stenosis (PTTS) were compared with a subgroup of 319 controls. Factors including medical comorbidity, type and setting of tracheostomy, and hospitalization details were analyzed.ResultsFive‐year incidence of PTTS was 2.6%. Obesity was the sole demographic factor associated with stenosis. Hospitalization‐related variables associated with stenosis included tracheostomy after 10 days of orotracheal intubation and endotracheal tube cuff pressure ≥30 mm H2O. The surgical variables associated with higher rates of stenosis included percutaneous technique and insertion of an initial tracheostomy tube size >6. Bjork flap creation was negatively associated with stenosis. In multivariable analysis, obesity and insertion of tracheostomy tube size >6 were identified as risk factors.ConclusionGreater than 10 days of orotracheal intubation prior to tracheostomy and endotracheal tube cuff pressure ≥30 mm H2O were associated with greater rates of subsequent tracheal stenosis. The only patient‐related factor associated with tracheal stenosis was obesity. Surgical variables associated with increased rates of subsequent stenosis included placement of a tracheostomy tube size >6, use of percutaneous technique, and failure to create a Bjork flap.
Impact of PET/CT on Staging and Treatment of Advanced Head and Neck Squamous Cell Carcinoma
Authors: Jorgensen Jeffery B. , Smith Russell B. , Coughlin Andrew , Spanos William C. , Lohr Michele M. , Sperry Steven M. , Militsakh Oleg , Zitsch Robert P. , Yueh Bevan , Dooley Laura M. , Panwar Aru , Galloway Tabitha L. I. , Pagedar Nitin A. 
Published: August 2018

ObjectiveTo understand the effects of positron emission tomography/computed tomography (PET/CT) evaluation on patients with previously untreated head and neck squamous cell carcinoma (HNSCC) with clinical evidence of regional lymph node involvement.Study DesignProspective blinded study.SettingTertiary care cancer center.Subjects and MethodsInformed consent was obtained and data collected from 52 consecutive previously untreated patients with HNSCC and clinical evidence of cervical metastasis. All patients underwent conventional evaluation for HNSCC and whole body PET/CT. Data were evaluated by 5 independent reviewers, who performed TNM staging per the American Joint Committee on Cancer (seventh edition) manual and proposed a treatment plan prior to viewing, and after reviewing, PET/CT. Cases where at least 3 of 5 reviewers agreed were considered significant.ResultsThere were 0 patients for whom review of the PET/CT altered the T‐class assessment (95% CI, 0‐6.8), 12 (23.1%) for whom PET/CT altered N classification (95% CI, 12.5‐34.5), and 2 (3.8%) for whom PET/CT altered the M classification (95% CI, 0.5‐13.2). For 5 patients (9.6%), overall stage was altered per PET/CT review (95% CI, 3.2‐21). For 3 patients (5.8%), PET/CT findings prompted reviewers to alter treatment recommendations (95% CI, 1.2‐15.9).ConclusionWhen added to more conventional patient evaluation, PET/CT results in changes to the TNM categories, but overall staging and treatment were less frequently affected. Whether PET/CT should be used routinely for patients with stage III and IV HNSCC is still subjective and merits further study.
A Comparison of Laser‐Protected Endotracheal Tubes
Authors: Burns James A. , Adlard Stephen D. , Kobler James B. , Tynan Monica A. , Petrillo Robert H. , Tracy Lauren F. 
Published: August 2018

ObjectivesTo compare the physical characteristics of 3 laser‐protected endotracheal tubes (LPETs) commonly used in endoscopic laser surgery. To report potential intraoperative problems related to LPET use and suggest practical solutions.Study DesignComparative analysis.SettingAcademic laboratory.Subjects and MethodsPhysical characteristics of the Mallinckrodt Laser‐Flex (MTL), Medtronic Laser‐Shield II (ML‐II), and Rusch LaserTubus (RL) were compared. The effect of bending LPETs on airflow resistance was estimated with a pressure transducer. The force required to pull each tube through the glottis and the pressure exerted during this maneuver were measured in a fresh cadaveric human larynx.ResultsThe design features and physical characteristics of LPETs differ, including varying balloon‐tip lengths. Bending LPETs to acute angles caused significant pressure increase within the RL tube (Δ 3.42 cm H2O) and minimal change within the ML‐II (Δ 0.12 cm H2O) and MTL (Δ 0.21 cm H2O) tubes. The average force required to pull the RL (48.12 g, P =. 003) and MTL (282.4 g, P =. 001) tubes through the glottis was 7.6× and 44.5× greater than that for the ML‐II (6.39 g). When pulled through the vocal folds, the ML‐II cuff exerted no detectable pressure, whereas higher pressures were measured for the RL (2.2 cm H2O) and MTL (6.5 cm H2O) tubes.ConclusionThe ML‐II tube had the most favorable characteristics, with minimal pressure during extubation and resistance to kinking. The RL tube kinks readily with a resultant increase in resistance to airflow. The MTL tube extends farther into the trachea due to a relatively elongated balloon‐tip configuration. Future LPET designs should incorporate features that avoid intraoperative difficulties related to airway protection and ventilation.