bluuebunny/crossref_metadata_2025 huggingface dataset:
Two‐level primitive‐equation baroclinic instability on an f‐plane
Authors: Fraedrich Klaus , Frisius Thomas
Published: February 2007

Baroclinic instability of a two‐level primitive equation model is represented by a dynamical system consisting of the four interacting fields of barotropic and baroclinic vorticity, divergence and temperature. The instability mechanism is illustrated in terms of a positive feedback loop with a succession of tendencies. It occurs at wavelengths longer than the short wave cut‐off, for which vortex stretching prevails over vertical temperature advection. Quasi‐geostrophy reduces the positive feedback loop to the interaction of the barotropic and baroclinic vorticity fields which are diagnostically linked to divergence and temperature by the omega equation and by geostrophy, respectively.
Retrieval of microphysical and morphological properties of volcanic ash plumes from satellite data: Application to Mt Ruapehu, New Zealand
Authors: Prata A. J. , Grant I. F.
Published: February 2007

A quantitative analysis of the properties of several Mt Ruapehu, New Zealand, ash plumes has been performed using multispectral satellite data from the AVHRR‐2 and ATSR‐2 instruments. The analysis includes: identification of the plume from background clouds using the ‘reverse’ absorption effect in the thermal channels: modelling and retrieval of particle sizes; determination of the plume height from cloud shadows, stereoscopy and meteorological data; and estimates of the mass of fine particles (radii less than 10 μm). A new spectral technique for identifying opaque, silica‐rich ash clouds is demonstrated by utilizing the near‐infrared (1.6 μm) and visible (0.67 μm) channels of the ATSR‐2, and the optical properties of a simple volcanic cloud are presented for use in radiative transfer studies. It is found that the Ruapehu eruption cloud contained silica‐rich ash particles with radii generally less than a few micrometres. The distribution of fine particles is monomodal with a dominant mode peak of about 3 μm radius. Mass loadings of fine particles are found to be in the range ≈︁1 to ≈︁7 mg m−3, and are consistent with estimates of mass loadings of volcanic clouds from eruptions of other volcanoes. The height of the plume top, derived from radiosonde data and plume‐top temperatures in the opaque regions, was found to be between 7.5 and 8.5 km, while the plume thickness was estimated to be between 1.5 and 3 km. Cloud height derived from ATSR‐2 stereoscopy on a different plume gave heights in the range 5 to 8 km.

The results of this study provide important information on the optical properties of nascent volcanic eruption plumes. This information may prove useful in determining the potential effects of volcanic clouds on local climate, and in assessing any hazard to aviation.
Sensitivity studies using a cloud‐resolving model simulation of the tropical west Pacific
Authors: Petch J. C. , Gray M. E. B.
Published: February 2007

It is important to understand the variability of results which can be produced in a cloud‐resolving model (CRM) before using its output to develop parametrizations. In the work presented here a broad range of sensitivity experiments are carried out so that the significance of each change to the model can be put into context. Changes to the parametrization of microphysics and radiation in the CRM are considered along with the influence of dimensionality, horizontal resolution and domain size. Further detailed sensitivity studies are then carried out to investigate the impact of the spatial and temporal distribution of the radiative heating.

The results presented show that, out of all the sensitivity studies considered, no particular feature or physical parametrization in a CRM dominates. The domain size, horizontal grid length, use of a third dimension and parametrization of microphysics all significantly impact the simulation in some way. Radiative heating has a large impact on the simulation because it dominates over the large‐scale forcing above 8 km. However, the magnitude of this impact is strongly dependent on other aspects of the model, such as the choice of microphysical scheme. A diurnal cycle, which is inherent in the large‐scale forcing, is not significantly enhanced by radiation in the CRM. However, accounting for the temporal and spatial variability in the radiative heating is important because neglecting this is shown to overestimate the strength of convection.
Symmetrization of lopsided vorticity monopoles and offset hurricane eyes
Authors: Prieto R. , Kossin J. P. , Schubert W. H.
Published: February 2007

This paper is a contribution towards better understanding of the continually occurring symmetrization processes in tropical cyclones. Before a tropical cyclone develops an eye, it can often possess an asymmetric monopolar vorticity distribution. As an idealized initial condition in a non‐divergent barotropic model, we use a lopsided monopole with different degrees of asymmetry of the monotonic vorticity field. We then study the axi‐symmetrization process which involves the ejection of a winding spiral band. For extreme asymmetric initial conditions, the band can produce regions of barotropic instability, resulting in nonlinear mixing of vorticity and the formation of polygonal structures. In a second series of experiments, we study the case of a tropical cyclone with a developed eye, modelled as a hollow‐tower vorticity distribution, i.e. an annular region of elevated vorticity, with low vorticity in the eye. If the eye is offset and the annular region of elevated vorticity is not of uniform width, complex symmetrization processes can occur, sometimes leading to a tripole structure of the hurricane's vorticity field. Long‐lived hurricane eyes are found for initial conditions with a slight offset. For such initial conditions, passive tracers can remain in the eye for as long as 72 hours, showing that in this model it is possible for air inside the eye to remain there for long periods of time, while moving coherently with the storm. Predictions of the axi‐symmetric final equilibrium states of the flow are obtained using the statistical mechanics theory of maximum Boltzmann mixing entropy. These predictions are then compared with results from the direct numerical integrations for both the lopsided monopole and the offset hurricane eye. The distribution of air‐parcel tracers initially placed in selective regions of vorticity for the direct numerical integrations are compared with results from the statistical theory.
Possible links between cloud optical depth and effective radius in remote sensing observations
Authors: Boers R. , Rotstayn L. D.
Published: February 2007

The theoretical relationship between cloud optical depth and effective radius is examined. The relationship between cloud optical depth and effective radius is shown to depend on (a) the relative variability of droplet concentration, cloud depth, mixing and precipitation, and (b) the correlation between the two most important parameters, namely cloud depth and droplet concentration. It is possible to obtain positive, negative or zero correlation between optical depth and effective radius for different values of (a) and (b). Of all these parameters, mixing appears to be the least important. If clouds are not affected by precipitation, negative correlations between optical depth and effective radius (the expected signature of the first indirect aerosol effect) can be caused by a small spread in cloud depths relative to that in droplet concentration, or (more importantly) by a positive correlation between droplet concentration and cloud depth.

Precipitation tends to reduce the correlation between optical depth and effective radius, because one of the main effects of precipitation is to increase the spread in droplet effective radius. If the effect of increases in aerosols is a reduction in precipitation, our results indicate that the correlation coefficient between optical depth and effective radius should increase, an effect that should be most clearly visible over the ocean. These findings illustrate the complexity of the physical processes that underpin the linkage of optical depth and effective radius.
Using a cloud‐resolving model to study the effects of subgrid‐scale variations in relative humidity on direct sulphate‐aerosol forcing
Authors: Petch J. C.
Published: February 2007

Cloud‐resolving model simulations over a tropical ocean and a mid‐latitude continental region have been used to investigate the influence of subgrid‐scale variations of relative humidity on the direct radiative forcing of sulphate aerosols. Offline radiation calculations based on output from a cloud‐resolving model, with and without sulphate aerosol included, are used to calculate the direct radiative forcing of the aerosol. This forcing is compared with results from single‐column radiation calculations typical of those produced by a climate model.

The results from this idealized study show that a typical climate model can underestimate the direct radiative forcing of aerosols by up to 80%. The errors in a climate‐model calculation are largest when the mean relative humidity is high or there are moist regions within a drier domain; this is usually reflected in a larger standard deviation of the relative humidity. Over the more humid tropical ocean, a climate model may underestimate the direct radiative forcing of sulphate aerosols by 43%, on average (ranging between 30% and 80%). Over the drier continental mid‐latitude region the average error is only 10%, but instantaneous values can exceed 50% during times when both the mean relative humidity and its standard deviation are large; this is typically close to convective events.
Modification of the wind speed profile caused by snowdrift: Results from observations
Authors: Bintanja Richard
Published: February 2007

This paper investigates how snowdrift influences the wind speed profile on the basis of meteorological and snowdrift data collected over an Antarctic snow surface during the austral summer. The friction associated with saltating snowdrift is found to significantly affect the wind speed profile by enhancing the apparent surface roughness. Several aspects of the wind speed data suggest the existence of the particle buoyancy effect associated with suspended snow particles. This effect has been theoretically predicted for snowdrift and experimentally verified for other two‐phase flows (e.g. suspended sediment in water). The observed impact of snowdrift saltation and suspension on the wind speed gradient, the total buoyancy and turbulent production rate are compared with theoretical/empirical estimates of the impact of saltation effects and particle buoyancy in suspension. It is shown that the particle buoyancy effect in snowdrift is very probably real and non‐negligible, but winds were not strong enough to demonstrate this conclusively.
An adaptive buddy check for observational quality control
Authors: Dee Dick P. , Rukhovets Leonid , Todling Ricardo , da Silva Arlindo M. , Larson Jay W.
Published: February 2007

An adaptive buddy‐check algorithm is presented that adjusts tolerances for suspect observations, based on the variability of surrounding data. The algorithm derives from a statistical hypothesis test combined with maximum‐likelihood covariance estimation. Its stability is shown to depend on the initial identification of outliers by a simple background check. The adaptive feature ensures that the final quality‐control decisions are not very sensitive to prescribed statistics of first‐guess and observation errors, nor on other approximations introduced into the algorithm.

The implementation of the algorithm in a global atmospheric data assimilation is described. Its performance is contrasted with that of a non‐adaptive buddy check, for the surface analysis of an extreme storm that took place over Europe on 27 December 1999. The adaptive algorithm allowed the inclusion of many important observations that differed greatly from the first guess and that would have been excluded on the basis of prescribed statistics. The analysis of the storm development was much improved as a result of these additional observations.
Radar observations of precipitation and airflow on the Mediterranean side of the Alps: Autumn 1998 and 1999
Authors: Houze Robert A. , James Curtis N. , Medina Socorro
Published: February 2007

This study constructs and analyses composite three‐dimensional fields of Doppler‐radar observed radial velocity and reflectivity for all precipitation events occurring in the Lago Maggiore region on the Mediterranean side of the Alps during autumn 1998 and 1999. Mean patterns for the two years are in close agreement with each other. The radar data are consistent with previous rain‐gauge studies in showing that the rain was heaviest over the lower windward slopes, and decreased toward higher terrain. The three‐dimensional reflectivity fields show that precipitation growth occurred mainly at low altitudes. The composite radar data show that the precipitation was most intense when the mean flow around the 2 km level was southerly or south‐easterly, i.e. when the mean flow was most perpendicular to the Alpine barrier.

Sounding data from Milan indicated the Froude number of the flow upstream of the Lago Maggiore region. When the Froude number was high, the flow proceeded directly up and over the terrain of the lower Alpine slopes. Under these unblocked conditions, the low‐level flow (including the layer from the surface to 2 km above mean sea level) rose directly up and over the terrain, and the precipitation was greatly enhanced over the lower windward slopes and over the portions of the Po Valley just upstream of the mountains. Under unblocked conditions, the precipitation enhancement only extended a short distance (a few tens of kilometres) upstream of the Alps. When the upstream Froude number computed from the Milan sounding was low (blocked conditions), the Doppler radial velocities indicated that the low‐level flow (in the layer below 2 km above mean sea level) turned cyclonically as it approached the Alpine barrier, instead of rising over the terrain. The composite radar reflectivity data showed less precipitation enhancement directly over the windward slope, but in contrast to the unblocked case showed that the precipitation was enhanced 140 km or more upstream of the terrain. Evidently, the low‐level flow began rising far in advance of the barrier in blocked conditions.

The 1998 and 1999 autumn data sample further indicates the relative roles of wind speed and stability, which are combined in the Froude number. When the wind speed upstream was strong (>8 m s−1), significant precipitation enhancement occurred on the windward slope of the Alps in the Lago Maggiore region, regardless of the static stability. However, the enhancement was far greater under unstable conditions. When the wind speed was weak (<8 m s−1), the precipitation was generally near or below average, except when the stability was low and some patchy enhancement occurred over the Po Valley just upwind of the Alps. A diurnal precipitation maximum occurred in the early morning hours (0700–1000 LST), possibly where down‐valley flow converged with synoptic‐scale up‐valley flow.
Modelling the generation of gravity waves by a maritime continent thunderstorm
Authors: Lane Todd P. , Reeder Michael J.
Published: February 2007

Observed wind and temperature profiles are used to initialize a model calculation of a maritime continent thunderstorm, and the numerical solution is used to explore the effect of tropospheric shear on the gravity‐wave generation. The resultant convective system is qualitatively similar to that observed. The modelled gravity waves propagate away from the cloud with wave‐fronts that are approximately circular, implying that the convective clouds do not generate waves which propagate in a preferred direction.

The gravity‐wave generation is related to the oscillation of the convective updraughts about their level of neutral buoyancy. While the general features of the gravity waves are similar in most respects to a previous study which used an idealized wind profile, the frequency of the gravity waves is Doppler‐shifted by the tropospheric wind shear. The result is a much broader power spectrum in comparison to the idealized cases.
Can an ensemble transform Kalman filter predict the reduction in forecast‐error variance produced by targeted observations?
Authors: Majumdar S. J. , Bishop C. H. , Etherton B. J. , Szunyogh I. , Toth Z.
Published: February 2007

The ensemble transform Kalman filter (ET KF) is currently used at the National Centers for Environmental Prediction (NCEP) to identify deployments of aircraft‐borne dropwindsondes that are likely to significantly improve 1‐3 day forecasts of winter storms over the continental United States. It is unique among existing targeted observing strategies in that it attempts to predict the reduction in forecast‐error variance associated with each deployment of targeted observations. To achieve this, the ET KF predicts the variance of ‘signals’ for each feasible deployment, where a signal represents the difference between two forecasts, initialized with and without the targeted observations. For linear forecast‐error evolution, the signal variance is equal to the reduction in forecast‐error variance, provided that observation‐ and background‐error covariances are accurately specified and identical to those produced by the operational data‐assimilation scheme. However, background‐error covariances assumed by the ET KF are both imperfect and different from the imperfect error covariances used in NCEP's 3D‐Var data‐assimilation scheme, and hence their signal statistics are likely to differ.

In spite of these differences, a linear relationship of positive gradient is found to exist between the ET KF signal variance and the sample variance of NCEP signal realizations at both the targeted analysis and forecast verification times, for 30 forecasts from the 2000 Winter Storm Reconnaissance Program. This relationship enables the NCEP signal variance to be predicted by the ET KF, via a statistical rescaling that corrects the ET KF's current over‐prediction of signal variance magnitude. A monotonically increasing relationship is also found to exist between the NCEP signal variance and the reduction in NCEP forecast‐error variance. The ET KF signal variance predictions can be used to make quantitative estimates of the forecast‐error‐variance reducing effect of targeted observations. Potential benefits include (i) making rapid decisions on when and where to deploy targeted observations, (ii) warning operational data quality‐control schemes against the rejection of observational data if the signal variance is large, and (iii) estimating the likelihood of economic benefit due to any future deployment of observations.
Flood frequency and routing processes at a confluence of the middle Yellow River in China
Authors: He Hongming , Zhou Jie , Yu Qian , Tian Yong Q. , Chen Robert F.
Published: February 2007

Floods cause environmental hazards and influence on socio‐economic activities. In this study, we evaluated the historic flood frequency at a confluence in the middle Yellow River, China. A non‐parametric, multivariate, empirical, orthogonal function matrix model, which consists of time correlation coefficients of flood discharge at different gauge stations and flood events was used for the analysis of flood frequency. The model addresses the characteristics of confluent floods such as frequency and the probability in multiple tributary rivers. Flood frequency analysis is often coupled with studies of hydrological routing processes that reduce the flood capacity of the rivers. Flood routing to the confluence were simulated using kinematic wave theory. Results of this flood frequency analysis showed that flooding frequency has intensified in the past 500 years, especially during the 19th century. Flooding in streams above the confluence was more frequent than in streams below the confluence. Over the last 2000 years, concurrent flooding in multiple tributary rivers accounted for 67.5% of the total flooding in the middle Yellow River. Simulation of flood routing processes shows that the decreased flooding capacity and elevated river bed of the shrunken main channel leads to an increased flood wave propagation time (24–52.3 h) in the study area after 1995. The model indicates that human activities, such as constructions of the Sanmenxia Dam, have changed flood routing boundary conditions and have contributed to the increased flood frequency at the confluence. Copyright © 2007 John Wiley & Sons, Ltd.
Long‐term and short‐term customer reaction: a two‐stage queueing approach
Authors: Ackere Ann van , Haxholdt Christian , Larsen Erik R.
Published: February 2007

We analyse a simple, deterministic queueing system with feedback. We model a customer's decision to seek service as a two‐stage process: (1) deciding whether or not to use a facility (become a customer), and (2) deciding the frequency of use (daily, weekly, monthly, etc.). We consider both a constant and a deterministic, time‐dependent usage pattern. We ignore variability, and focus on three forms of feedback: (1) the service rate increases as queue length increases; (2) the frequency with which customers use the service depends on customers' perception of recent waiting times; and (3) the number of customers depends on their perception of long‐term average waiting time. Although highly stylised, this model captures the essential features of many real‐life systems whose average arrival rate varies over time. The main conclusions are that more capacity can make the system less manageable, and a stronger external cycle can be a stabilising factor. The model turns out to be remarkably robust to external disturbances. Copyright © 2006 John Wiley & Sons, Ltd.
Viruses, lipid rafts and signal transduction
Authors: Rauch Susanne , Fackler Oliver T.
Published: February 2007

Lipid rafts are defined as highly dynamic microdomains in cellular membranes that are enriched in sphingolipids, cholesterol and raft‐targeted proteins. This particular lipid and protein composition is thought to facilitate protein‐protein interactions to create microdomains with distinct biological properties. Lipid rafts have been implicated in central cellular processes such as signal transduction and protein trafficking. This review focuses on strategies used by three viral pathogens (measles virus, Epstein‐Barr virus and human immunodeficiency virus) to manipulate their target cells by altering the signal transduction properties of such cellular microdomains in the infected host.
Ranked reservoir sampling: an extension to the reservoir sampling algorithm
Authors: Kirkham C. C.
Published: February 2007

This paper describes a simple extension to the reservoir sampling algorithm to allow its use with ranked records. Here the fixed‐sized sample must include records in order of rank, but a fair selection must occur to choose the lowest‐ranked records included. The result is produced after a single pass through the records. Copyright © 2007 John Wiley & Sons, Ltd.
Evolution@home: observations on participant choice, work unit variation and low‐effort global computing
Authors: Loewe Laurence
Published: February 2007

Many simulation efforts in ecology and evolutionary biology employ individual‐based models that are well suited for including many biological details. These models often pose serious computational challenges if all biologically interesting parameter combinations are to be explored. The challenges are even greater for biologists who often lack supercomputing facilities and the manpower for implementing complex global computing systems such as SETI@home. Under such limiting conditions, evolution@home started as a one‐man effort to distribute simulations of Muller's ratchet to Internet‐connected computers of participants from the general public. This paper addresses experiences in low‐effort global computing made with evolution@home over more than four years. It shows how allowing participants to choose the class of computational complexity they want to contribute to can help to deal with the bewildering variety of computational complexities that easily result from individual‐based models. Results suggest that, as a first rough approximation, participants' complexity choices are distributed surprisingly even over all reasonable classes of CPU‐time and RAM requirements. More often than not, participants tend to finish the simulations they start, if they are committed enough to submit any results at all. Potential uses of intermediate simulation results are discussed and the error of magnitude is introduced to help to deal with imprecise CPU‐time predictions. Experiences with the choices of over 300 users who have contributed more than 100 000 simulations with a total of over 80 years CPU time are reviewed. Copyright © 2007 John Wiley & Sons, Ltd.
Large calcifications in ovaries otherwise normal on ultrasound
Authors: Brown D. L. , Laing F. C. , Welch W. R.
Published: February 2007

Objective

To evaluate calcifications ≥ 5 mm in length in ovaries that are otherwise normal on ultrasound, and to determine whether such large ovarian calcifications are an indicator of ovarian neoplasm.

Methods

This was a retrospective study reviewing pelvic ultrasound results at our unit between October 1994 and April 2002 to identify patients with ovarian calcifications that were ≥ 5 mm in maximum length in otherwise normal ovaries, and who also had follow‐up imaging studies. Patient medical histories were reviewed, calcification characteristics, including number, size, shape and laterality of calcifications, were recorded and follow‐up imaging studies were reviewed to assess change in size of the calcification and to see if a neoplasm had developed.

Results

The study group consisted of 28 patients. The mean length of imaging follow‐up was 35.2 ± 30.7 months. The mean size of the calcifications was 7.4 ± 2.3 (range, 5–13) mm. The calcification remained stable in all 28 patients and no ovarian neoplasms developed in any of the patients. Histological confirmation was available in one patient and this revealed dystrophic calcification in a corpus albicans.

Conclusion

Calcifications ranging from 5 to 13 mm in length in otherwise normal ovaries remain stable on follow‐up imaging and are not an indicator of current or future ovarian neoplasm. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
Effect of aromatic ring in the alkyl chain on surface properties of arylalkyl surfactant solutions
Authors: Xu Zhigang , Li Pengfei , Qiao Weihong , Li Zongshi , Cheng Lubo
Published: February 2007

Surface properties of two series of anionic arylalkyl surfactants, containing different aromatic rings in the straight aliphatic chain, sodium N‐aryloleyl‐N‐methyl‐2‐aminoethanesulfonates and sodium N‐aryloleyl p‐methoxyanili‐nesulfonates, were investigated. An increase of the aromatic ring size in the alkyl chain increases the critical micelle concentration (CMC) and surface tension at CMC. However, this also decreases the efficiency and effectiveness in reducing water surface tension. The dominant factor of the decrease of efficiency and effectiveness is attributed to the function of the hydrophilic segment and hydrophobic segment for arylalkyl surfactants, respectively. The same results are found in the standard free energy of adsorption (ΔGoads) and the standard free energy of micellization (ΔGomic) values. Moreover, with the increase of the aromatic ring size, the adsorption and micellization of arylalkyl surfactants begin to weaken. The data indicate that some parts of surface properties for arylalkyl surfactants are affected by the bulkiness of the arylalkyl chain. The results provide opportunities for further detailed examination of surface properties of arylalkyl surfactants with other branched alkyl chains.
Experimental design for optimization of peroxide formulation stability and cost
Authors: Blanco Marcel , Coello Jordi , Sánchez M. Jesús
Published: February 2007

Cleaning formulations typically contain, in addition to surfactant, a bleaching agent that is usually hydrogen peroxide. This active agent has the disadvantage that it becomes unstable with time, which necessitates the use of various additives in the formulation to ensure its stability. In this work, a study of the different types of surfactants, chelating agents, radical scavengers, stabilizers, and solvents commonly used in the bleaching industry, was made to identify the mixture that better stabilizes an aqueous solution of hydrogen peroxide.

The strategy used starts with a screening step based on a hyper‐Greco‐Latin square design. In subsequent steps, a Box‐Wilson design is used to construct a response surface model to identify the composition ensuring the highest possible stability in the formulation. A desirability function is then obtained that allows the stability of the formulation to be maximized and its cost simultaneously minimized. Such a function is optimized using the Nelder‐Mead algorithm.

The stability study was made by heating the mixtures at 60°C for variable periods of time. A mixture containing four of these additives was found to provide the best stability, and the solvent did not have any effect on the stabilization. However, this mixture exceeded the expectations in terms of cost, so the composition was adjusted to obtain the best compromise between stability and cost. As the stabilizer is the more expensive additive, in this optimization step its composition was reduced. In the final formulation, the stabilizer concentration can be reduced by up to 23% with respect to that obtained in the previous step without detracting from stability, thereby saving 18.8%.
Identification and production of n−8 odd‐numbered polyunsaturated fatty acids by a Δ12 desaturation‐defective mutant of Mortierella alpina 1S‐4
Authors: Zhang Shuo , Sakuradani Eiji , Shimizu Sakayu
Published: February 2007

A mutant of Mortierella alpina, JT‐180, which is defective in its Δ12 desaturase activity but exhibits enhanced activities of Δ5 and Δ6 desaturases, produced a high proportion (up to 80%) of odd‐chain FA when grown on 3% n‐heptadecane. Following growth of the mutant on n‐heptadecane, three unusual odd‐chain fatty acyl residues were identified as 6,9‐heptadecadienoic acid (17∶2), 8,11‐nonadecadienoic acid (19∶2), and 5,8,11‐nonadecatrienoic acid (19∶3) by means of GC‐MS, MS‐MS, and NMR analysed. The mycelial contents of these FA reached 20.3, 3.6, and 5.8 ⧎/g dry mycelia, respectively, when it was cultivated in medium comprising 4% (vol/vol) n‐heptadecane and 1% (wt/vol) yeast extract, pH 6.0, at 28°C for 7 d. The biosynthetic route (n−8 route) to 19∶3 was presumed to mimic the n−9 route to Mead acid (20∶3 n−9) in mammals: 17∶0→9–17∶1→6,9–17∶2→8,11–19∶2→5,8,11–19∶3.
Pediatric retropharyngeal lymphadenitis: Differentiation from retropharyngeal abscess and treatment implications
Authors: Shefelbine Sarah E. , Mancuso Anthony A. , Gajewski Byron J. , Ojiri Hiroya , Stringer Scott , Sedwick Jack D.
Published: February 2007

Objectives

Our objectives were to review the retropharyngeal anatomy, define retropharyngeal adenitis and abscess, and determine if CT may guide the clinician in treatment planning for pediatric retropharyngeal infections.

Study Design and Setting

A retrospective chart review and CT scan review of 30 children with retropharyngeal infections.

Results

All patients had retropharyngeal adenitis. Average volume of the low‐attenuation focus in the medical treatment group was 1.2 cm3. Average volume in the surgical group was 4 cm3. Surgery patients with no purulent findings were then grouped with the medical treatment group; the average volume of the low‐attenuation focus in this group was 2.2 cm3. Average volume in the group in which purulence was identified was 4.4 cm3.

Conclusion

CT can identify patients with retropharyngeal infections who have a high likelihood of being successfully treated with antibiotics alone.

Significance

CT imaging may assist in avoiding unnecessary surgical exploration.
Vocal fold augmentation with calcium hydroxylapatite (CaHA)
Authors: Rosen Clark A. , Gartner‐Schmidt Jackie , Casiano Roy , Anderson Timothy D. , Johnson Felicia , Reussner Lee , Remacle Marc , Sataloff Robert T. , Abitbol Jean , Shaw Gary , Archer Sanford , McWhorter Andrew
Published: February 2007

Objectives

Evaluate the effectiveness of CaHA injection for patients with glottal incompetence.

Methods

Multi‐center, open‐label, prospective clinical study with each patient serving as his/her own control. Voice‐related outcome measures were collected for pre‐injection and 1, 3, and 6 months.

Results

Sixty‐eight patients were available for evaluation. Fifty percent of the injection procedures were done in office. Fifty‐seven percent were diagnosed with unilateral paralysis and 42% with glottal incompetence with mobile vocal folds. Patient satisfaction 6 months post showed 56% had significantly improved voice and 38% reported moderately improved voice. Paired t tests from baseline to 6 months showed significant improvements on the VHI and VAS (vocal effort), CAPE‐V judgments of voice severity and videoendostroboscopy ratings of glottal closure, and objective voice measures of glottal closure (MPT and S:Z ratio).

Conclusions

Preliminary results in this large cohort of patients demonstrate excellent clinical results.
A mandibular advancement device for the ENT office to treat obstructive sleep apnea
Authors: Maurer Joachim T. , Huber Kerstin , Verse Thomas , Hörmann Karl , Stuck Boris
Published: February 2007

Objective

To prospectively evaluate the efficacy of the mandibular advancement device (MAD) Somnoguard in the treatment of OSA patients.

Study Design and Setting

Forty‐four patients with OSA and noncompliant to continuous positive airway pressure were enrolled in this case series. Somnoguard is made of thermoplastic material. Direct intraoral fitting was done by an otorhinolaryngologist. Polysomnographic data concerning sleep and respiration were assessed at baseline and after familiarization with the MAD.

Results

Sleep efficiency and sleep stages distribution did not change significantly. The RDI could be reduced from 31.5 ± 17.6 to 18.2 ± 17.0 (P < 0.05), the minimal oxygen saturation increased from 78 ± 12.9 to 82 ± 12.5% (P < 0.05). According to standard criteria, 18 patients were cured, 12 were improved, 8 remained unchanged, and 6 worsened. Snoring time decreased from 223 ± 132 to 183 ± 134 minutes (P < 0.05).

Conclusion and Significance

With Somnoguard 68% of the enrolled OSA patients could be cured or substantially improved. It is a simple MAD for the otolaryngologist.
Radical surgery: Effect on quality of life and pain in chronic rhinosinusitis
Authors: Videler Ward J.M. , van Drunen Cornelis M. , van der Meulen Freerk W. , Fokkens Wytske J.
Published: February 2007

Objectives

Despite effective medical therapy and repetitive endoscopic sinus surgery in the treatment of chronic rhinosinusitis, there still remains a small group of patients without improvement of symptoms. This study evaluates the effect of radical surgery on quality of life and pain in these patients with recalcitrant disease.

Study Design

A prospective, questionnaire‐based study was conducted in 23 patients who underwent Denker's procedure for refractory chronic rhinosinusitis. Quality of life and pain were evaluated before surgery and 12 months and 2 years after surgery with the SF‐36 and McGill Pain Questionnaire.

Results

Seven of the eight mean scores of the SF‐36 postoperatively improved after surgery, with statistical significance for Role Physical (RP) P = 0.048. Bodily pain showed a strong tendency to significance. Results of the McGill Pain Questionnaire show a significant improvement in most of the subscores after surgery implying less pain.

Conclusion

Radical surgery improves the physical burden of chronic rhinosinusitis and pain experience in patients with therapy resistant chronic rhinosinusitis.
A clinico‐pathological study of laryngeal and hypopharyngeal carcinoma: Correlation of cord‐arytenoid mobility with histopathologic involvement
Authors: Katιlmιş Hüseyin , Öztürkcan Sedat , Özdemir İsmail , Adadan Işιl , Tunç Aziz , Akder Ayşegül , Başoğlu Sinan
Published: February 2007

Objective

This study evaluates the vocal cord and arytenoid mobility in relation to the tumoral involvement of the cricoarytenoid joint (CAJ), thyroarytenoid (TA) muscle, and posterior cricoarytenoid (PCA) muscle in whole‐organ sections of total laryngectomy specimens.

Study Design and Setting

The study was prospectively carried out between 1998 and 2003 and involved 133 primary squamous cell carcinoma cases of larynx or pyriform sinus that were treated with total laryngectomy. Preoperative mobility of vocal cords and arytenoids were evaluated seperately and correlated with histopathologic findings.

Results

In cases with fixed vocal cord CAJ, TA muscle, and PCA muscle were involved in 42.4%, 72.9%, and 27.1% of the cases, respectively, while in cases with fixed arytenoid these structures were affected in 40%, 66.3%, and 25.3% of the cases. Weight effect seemed to play a role in 60% and 50% of the cases of supraglottic and pyriform sinus carcinoma, respectively.

Conclusion

Careful evaluation of the mobility of the cord arytenoid unit separately helps the surgeon to better understand the patterns of tumoral extension guiding for the appropriate surgery which should be undertaken.
Lacustrine evidence for moisture changes in the Nebraska Sand Hills during Marine Isotope Stage 3
Authors: Jacobs Kimberly C. , Fritz Sherilyn C. , Swinehart James B.
Published: February 2007

In the central Great Plains of North America, loess stratigraphy suggests that climate during the late Pleistocene was cold and dry. However, this record is discontinuous, and there are few other records of late-Pleistocene conditions. Cobb Basin, located on the northern edge of the Nebraska Sand Hills, contains lacustrine sediments deposited during Marine Isotope Stage 3, beginning approximately 45,000 cal yr BP and continuing for at least 10,000 yr. The lake was formed by a dune dam blockage on the ancient Niobrara River, and its deposits contain a diatom record that indicates changes through time in lake depth driven by changes in effective moisture. During the earliest stages of lake formation, the climate was arid enough to mobilize dunes and emplace dune sand into a blocking position within the Niobrara streambed. Diatom assemblages suggest that lake-level was shallow at formation, increased substantially during a wet interval, and then became shallow again, as arid conditions resumed. By about 27,000 cal yr BP the lake was filled, and a shallow ephemeral river occupied the basin.
Parasite vaccines – recent progress and problems associated with their development
Authors: KNOX D. P. , REDMOND D. L.
Published: February 2007

The treatment and prevention of parasitism in both humans and livestock continues to rely almost exclusively on the use of antiparasitic drugs – an approach which has limitations, particularly as reinfection, which occurs rapidly in endemic regions, is not prevented. In addition, the widespread appearance of drug-resistant parasites of animals (Kaplan, 2004;) together with emerging evidence of resistance problems in human parasites (Fallonet al. 1995; Ismailet al. 1996; De Clerqet al. 1997; East African Network for Monitoring Antimalarial Treatment, 2003), emphasise the importance of developing alternative methods of control, with anti-parasite vaccines a prime target.
Vaccines against blood-feeding nematodes of humans and livestock
Authors: BETHONY J. M. , LOUKAS A. , HOTEZ P. J. , KNOX D. P.
Published: February 2007

This paper summarises the progress towards vaccine development against the major blood-feeding nematodes of man and livestock, the hookworms andHaemonchus contortus, respectively. The impact of the diseases and the drivers for vaccine development are summarized as well as the anticipated impact of the host immune response on vaccine design. The performance requirements are discussed and progress towards these objectives using defined larval and adult antigens, many of these being shared between species. Specific examples include theAncylostomasecreted proteins and homologues inHaemonchusas well as proteases used for digestion of the blood meal. This discussion shows that many of the major vaccine candidates are shared between these blood-feeding species, not only those from the blood-feeding stages but also those expressed by infective L3s in the early stages of infection. Challenges for the future include: exploiting the expanding genome information for antigen discovery, use of different recombinant protein expression systems, formulation with new adjuvants, and novel methods of field testing vaccine efficacy.
Soundscape - eine Möglichkeit kreativer Betätigung für Kinder und Jugendliche mit geistiger Behinderung?
Authors: Bailly Daniel
Published: February 2007

Zusammenfassung. Der Begriff “soundscape“ setzt sich zusammen aus den englischen Wörtern “sound“ und “landscape“ und beschreibt alle uns permanent umgebenden akustischen Ereignisse. Die “Klanglandschaft“ ist omnipräsent! Soundscapes kann man aus ihrem genuinen Entstehungsort, -moment und -kontext entheben, in dem man vor Ort Aufnahmen macht und diese dann später an einem anderen Ort, in einem anderen Moment und Kontext erklingen lässt. Dadurch treten oft unerwartete ‘Qualitäten‘ des Audiomaterials zu Tage, besonders dann, wenn man die Klänge und Geräusche durch Arrangieren in einen neuen Zusammenhang bringt. Kern dieses Textes ist es, Schülerinnen und Schülern mit geistiger Behinderung durch die Anbahnung aufmerksamen Hinhörens ihre akustische Umgebung näher zu bringen - bewusst zu machen. Neben der Möglichkeit, über aufmerksames Hin-Hören Alltagskompetenzen zu erlernen (z.B. Sicherheit im Straßenverkehr) stehen hier vor Allem die Aspekte des kreativen Schaffens im Vordergrund! Bevor ich im zweiten Teil dieses Textes (in der nächsten Ausgabe) näher auf didaktische und methodische Überlegungen für eine Unterrichtsreihe “Soundscape“ eingehe, sollen vorweg jene zentralen Begriffe erläutert werden, die diesem Text zu Grunde liegen.
Semantic Memory Functioning Across the Adult Life Span
Authors: Bäckman Lars , Nilsson Lars-Göran
Published: February 2007

Using data from the first wave of data collection in the Betula project, this research examined semantic memory performance in adulthood and old age (N = 1000). The Betula project is a 10-year longitudinal study on memory and health that involves participants from 10 age groups: 35, 40, 45, …, and 80 years of age. Results from tests of verbal fluency and vocabulary indicated no performance variation between 35 and 50 years of age, followed by a gradual deterioration with increasing age. In a test of general knowledge, only the two oldest cohorts showed deficits. When educational level was statistically controlled, a different pattern of results was seen: the middle-aged adults performed at the highest level and, with the exception of one fluency test, no age-related deficits were observed before 75 years of age. These results suggest that, although there may be age-related deficits in semantic memory in the general population, education appears to be a more important factor than adult age per se for semantic memory functioning. The data support the view that activation of preexisting memory representations is relatively unaffected by the adult aging process, and demonstrate the pivotal role of cultural factors (e.g., education, verbal experience) in proficient semantic memory functioning.
Observed relationship between surface specific humidity, integrated water vapor, and longwave downward radiation at different altitudes
Authors: Ruckstuhl Christian , Philipona Rolf , Morland June , Ohmura Atsumu
Published: February 2007

Atmospheric water vapor and surface humidity strongly influence the radiation budget at the Earth's surface. Water vapor not only absorbs solar radiation in the atmosphere, but as the most important greenhouse gas it also largely absorbs terrestrial longwave radiation and emits part of it back to the surface. Using surface observations, like longwave downward radiation (LDR), surface specific humidity (q) and GPS derived integrated water vapor (IWV), we investigated the relation between q and IWV and show how water vapor influences LDR. Radiation data from the Alpine Surface Radiation Budget (ASRB) network, surface humidity from MeteoSwiss and GPS IWV from the STARTWAVE database are used in this analysis. Measurements were taken at four different sites in Switzerland at elevations between 388 and 3584 m above sea level and for the period 2001 to 2005. On monthly means the analysis shows a strong linear relation between IWV and q for all‐sky as well as for cloud‐free situations. The slope of the IWV‐q linear regression line decreases with increasing altitude of the station. This is explained by the faster decrease of IWV than of q with height. Both q and IWV are strongly related with LDR measured at the Earth's surface. LDR can be parameterized with a power function, depending only on humidity. The estimation of LDR with IWV has an uncertainty of less than 5% on monthly means. At lower altitudes with higher humidity, the sensitivity of LDR to changes in q and IWV is smaller because of saturation of longwave absorption in the atmospheric window.
Liver fibrosis: cellular mechanisms of progression and resolution
Authors: Henderson Neil C. , Iredale John P.
Published: February 2007

Liver fibrosis represents a major worldwide health care burden. The last 15 years have seen a rapid growth in our understanding of the pathogenesis of this clinically relevant model of inflammation and repair. This work is likely to inform the design of effective antifibrotic therapies in the near future. In this review, we examine how the innate and adaptive immune response interacts with other key cell types in the liver, such as the myofibroblast, regulating the process of hepatic fibrosis and, where relevant, resolution of fibrosis with remodelling. Emphasis is placed on the increasing knowledge that has been generated by the use of transgenic animals and animals in which specific cell lines have been deleted. Additionally, we review the increasing evidence that, although significant numbers of wound-healing myofibroblasts are derived from the hepatic stellate cell, significant contributions may occur from other cell lineages, including those from distant sites such as bone marrow stem cells.