bluuebunny/crossref_metadata_2025 huggingface dataset:
Frequency Modulation During Song in a Suboscine Does Not Require Vocal Muscles
Authors: Amador Ana , Goller Franz , Mindlin Gabriel B.
Published: February 2008

The physiology of sound production in suboscines is poorly investigated. Suboscines are thought to develop song innately unlike the closely related oscines. Comparing phonatory mechanisms might therefore provide interesting insight into the evolution of vocal learning. Here we investigate sound production and control of sound frequency in the Great Kiskadee ( Pitangus sulfuratus) by recording air sac pressure and vocalizations during spontaneously generated song. In all the songs and calls recorded, the modulations of the fundamental frequency are highly correlated to air sac pressure. To test whether this relationship reflects frequency control by changing respiratory activity or indicates synchronized vocal control, we denervated the syringeal muscles by bilateral resection of the tracheosyringeal nerve. After denervation, the strong correlation between fundamental frequency and air sac pressure patterns remained unchanged. A single linear regression relates sound frequency to air sac pressure in the intact and denervated birds. This surprising lack of control by syringeal muscles of frequency in Kiskadees, in strong contrast to songbirds, poses the question of how air sac pressure regulates sound frequency. To explore this question theoretically, we assume a nonlinear restitution force for the oscillating membrane folds in a two mass model of sound production. This nonlinear restitution force is essential to reproduce the frequency modulations of the observed vocalizations.
Responses to Binary Taste Mixtures in the Nucleus of the Solitary Tract: Neural Coding With Firing Rate
Authors: Chen Jen-Yung , Di Lorenzo Patricia M.
Published: February 2008

The contribution of gustation to the perception of food requires an understanding of how neurons represent mixtures of taste qualities. In the periphery, separate groups of fibers, labeled by the stimulus that evokes the best (largest) response, appear to respond to each component of a mixture. In the brain, identification of analogous groups of neurons is hampered by trial-to-trial variability in response magnitude. In addition, convergence of different fiber types onto central neurons may complicate the classification scheme. To investigate these issues, electrophysiological responses to four tastants: sucrose, NaCl, HCl, and quinine, and their binary mixtures were recorded from 56 cells in the nucleus of the solitary tract (NTS, the 1st synapse in the central gustatory pathway) of the anesthetized rat. For 36 of these cells, all 10 stimuli were repeated at least five times (range: 5–23; median = 10). Results showed that 39% of these cells changed their best stimulus across stimulus repetitions, suggesting that response magnitude (firing rate) on any given trial produces an ambiguous message. Averaged across replicate trials, mixture responses most often approximated the response to the more effective component of the mixture. Cells that responded best to a taste mixture rather than any single-component tastant were identified. These cells were more broadly tuned than were cells that responded best to single-component stimuli and showed evidence of convergence from more than one best stimulus fiber type. Functionally, mixture-best cells may amplify the neural signal produced by unique configurations of basic taste qualities.
What's That Sound? Auditory Area CLM Encodes Stimulus Surprise, Not Intensity or Intensity Changes
Authors: Gill Patrick , Woolley Sarah M. N. , Fremouw Thane , Theunissen Frédéric E.
Published: February 2008

High-level sensory neurons encoding natural stimuli are not well described by linear models operating on the time-varying stimulus intensity. Here we show that firing rates of neurons in a secondary sensory forebrain area can be better modeled by linear functions of how surprising the stimulus is. We modeled auditory neurons in the caudal lateral mesopallium (CLM) of adult male zebra finches under urethane anesthesia with linear filters convolved not with stimulus intensity, but with stimulus surprise. Surprise was quantified as the logarithm of the probability of the stimulus given the local recent stimulus history and expectations based on conspecific song. Using our surprise method, the predictions of neural responses to conspecific song improved by 67% relative to those obtained using stimulus intensity. Similar prediction improvements cannot be replicated by assuming CLM performs derivative detection. The explanatory power of surprise increased from the midbrain through the primary forebrain and to CLM. When the stimulus presented was a random synthetic ripple noise, CLM neurons (but not neurons in lower auditory areas) were best described as if they were expecting conspecific song, finding the inconsistencies between birdsong and noise surprising. In summary, spikes in CLM neurons indicate stimulus surprise more than they indicate stimulus intensity features. The concept of stimulus surprise may be useful for modeling neural responses in other higher-order sensory areas whose functions have been poorly understood.
Spatial Heterogeneity of Cortical Receptive Fields and Its Impact on Multisensory Interactions
Authors: Carriere Brian N. , Royal David W. , Wallace Mark T.
Published: February 2008

Investigations of multisensory processing at the level of the single neuron have illustrated the importance of the spatial and temporal relationship of the paired stimuli and their relative effectiveness in determining the product of the resultant interaction. Although these principles provide a good first-order description of the interactive process, they were derived by treating space, time, and effectiveness as independent factors. In the anterior ectosylvian sulcus (AES) of the cat, previous work hinted that the spatial receptive field (SRF) architecture of multisensory neurons might play an important role in multisensory processing due to differences in the vigor of responses to identical stimuli placed at different locations within the SRF. In this study the impact of SRF architecture on cortical multisensory processing was investigated using semichronic single-unit electrophysiological experiments targeting a multisensory domain of the cat AES. The visual and auditory SRFs of AES multisensory neurons exhibited striking response heterogeneity, with SRF architecture appearing to play a major role in the multisensory interactions. The deterministic role of SRF architecture was tightly coupled to the manner in which stimulus location modulated the responsiveness of the neuron. Thus multisensory stimulus combinations at weakly effective locations within the SRF resulted in large (often superadditive) response enhancements, whereas combinations at more effective spatial locations resulted in smaller (additive/subadditive) interactions. These results provide important insights into the spatial organization and processing capabilities of cortical multisensory neurons, features that may provide important clues as to the functional roles played by this area in spatially directed perceptual processes.
WLAN Technologies for Audio Delivery
Authors: Tatlas Nicolas-Alexander , Floros Andreas , Zarouchas Thomas , Mourjopoulos John
Published: February 2008

Audio delivery and reproduction for home or professional applications may greatly benefit from the adoption of digital wireless local area network (WLAN) technologies. The most challenging aspect of such integration relates the synchronized and robust real-time streaming of multiple audio channels to multipoint receivers, for example, wireless active speakers. Here, it is shown that current WLAN solutions are susceptible to transmission errors. A detailed study of the IEEE802.11e protocol (currently under ratification) is also presented and all relevant distortions are assessed via an analytical and experimental methodology. A novel synchronization scheme is also introduced, allowing optimized playback for multiple receivers. The perceptual audio performance is assessed for both stereo and 5-channel applications based on either PCM or compressed audio signals.
Clinical Potential of Quantum Dots
Authors: Iga Arthur M. , Robertson John H. P. , Winslet Marc C. , Seifalian Alexander M.
Published: February 2008

Advances in nanotechnology have led to the development of novel fluorescent probes called quantum dots. Quantum dots have revolutionalized the processes of tagging molecules within research settings and are improving sentinel lymph node mapping and identification in vivo studies. As the unique physical and chemical properties of these fluorescent probes are being unraveled, new potential methods of early cancer detection, rapid spread and therapeutic management, that is, photodynamic therapy are being explored. Encouraging results of optical and real time identification of sentinel lymph nodes and lymph flow using quantum dots in vivo models are emerging. Quantum dots have also superseded many of the limitations of organic fluorophores and are a promising alternative as a research tool. In this review, we examine the promising clinical potential of quantum dots, their hindrances for clinical use and the current progress in abrogating their inherent toxicity.
Superparamagnetic Iron Oxide Nanoparticles Coated with Galactose-Carrying Polymer for Hepatocyte Targeting
Authors: Yoo Mi Kyong , Kim In Yong , Kim Eun Mi , Jeong Hwan-Jeong , Lee Chang-Moon , Jeong Yong Yeon , Akaike Toshihiro , Cho Chong Su
Published: February 2008

Our goal is to develop the functionalized superparamagnetic iron oxide nanoparticles (SPIONs) demonstrating the capacities to be delivered in liver specifically and to be dispersed in physiological environment stably. For this purpose, SPIONs were coated with polyvinylbenzyl-O-β-D-galactopyranosyl-D-gluconamide (PVLA) having galactose moieties to be recognized by asialoglycoprotein receptors (ASGP-R) on hepatocytes. For use as a control, we also prepared SPIONs coordinated with 2-pyrrolidone. The sizes, size distribution, structure, and coating of the nanoparticles were characterized by transmission electron microscopy (TEM), electrophoretic light scattering spectrophotometer (ELS), X-ray diffractometer (XRD), and Fourier transform infrared (FT-IR), respectively. Intracellular uptake of the PVLA-coated SPIONs was visualized by confocal laser scanning microscopy, and their hepatocyte-specific delivery was also investigated through magnetic resonance (MR) images of rat liver. MRI experimental results indicated that the PVLA-coated SPIONs possess the more specific accumulation property in liver compared with control, which suggests their potential utility as liver-targeting MRI contrast agent.
Fixed Points for Multivalued Mappings in Uniformly Convex Metric Spaces
Authors: Kaewcharoen A. , Panyanak B.
Published: February 2008

The purpose of this paper is to ensure the existence of fixed points for multivalued nonexpansive weakly inward nonself‐mappings in uniformly convex metric spaces. This extends a result of Lim (1980) in Banach spaces. All results of Dhompongsa et al. (2005) and Chaoha and Phon‐on (2006) are also extended.
Priapism, Ecstasy, and Marijuana: Is There a Connection?
Authors: Tran Quan T. , Wallace Robyn A. , Sim Esther H. A.
Published: February 2008

Priapism is a urological emergency with multiple aetiologies including drug induced. Currently, there have been no reports of priapism induced by the combination of ecstasy and marijuana. We speculated on the potential mechanisms for acute drug-induced priapism resulting from ingestion of these two common illicit drugs.
Periodic Orbits with Least Period Three on the Circle
Authors: Zhao Xuezhi
Published: February 2008

The self-maps on the circle having periodic orbits with least period 3 are classified into relative homotopy-conjugacy classes. We will show that except for the maps in one exceptional class, all these kinds of maps have periodic orbits with all least periods but 2. Thus, a kind of Sharkovskii's type theorem on the circle is obtained.
Biologically Inspired Synthesis Route to Three‐Dimensionally Structured Inorganic Thin Films
Authors: Schwenzer Birgit , Morse Daniel E.
Published: February 2008

Inorganic thin films (hydroxide, oxide, and phosphate materials) that are textured on a submicron scale have been prepared from aqueous metal salt solutions at room temperature using vapor‐diffusion catalysis. This generic synthesis approach mimics the essential advantages of the catalytic and structure‐directing mechanisms observed for the formation of silica skeletons of marine sponges. Chemical composition, crystallinity, and the three‐dimensional morphology of films prepared by this method are extremely sensitive to changes in the synthesis conditions, such as concentrations, reaction times, and the presence and nature of substrate materials. Focusing on different materials systems, the reaction mechanism for the formation of these thin films and the influence of different reaction parameters on the product are explained.
Circular Microstrip Patch Array Antenna for C‐Band Altimeter System
Authors: Keshtkar Asghar , Keshtkar Ahmad , Dastkhosh A. R.
Published: February 2008

The purpose of this paper is to discuss the practical and experimental results obtained from the design, construction, and test of an array of circular microstrip elements. The aim of this antenna construction was to obtain a gain of 12 dB, an acceptable pattern, and a reasonable value of SWR for altimeter system application. In this paper, the cavity model was applied to analyze the patch and a proper combination of ordinary formulas; HPHFSS software and Microwave Office software were used. The array includes four circular elements with equal sizes and equal spacing and was planed on a substrate. The method of analysis, design, and development of this antenna array is explained completely here. The antenna is simulated and is completely analyzed by commercial HPHFSS software. Microwave Office 2006 software has been used to initially simulate and find the optimum design and results. Comparison between practical results and the results obtained from the simulation shows that we reached our goals by a great degree of validity.
Observations on Jet-Flame Blowout
Authors: Moore N. J. , McCraw J. L. , Lyons K. M.
Published: February 2008

The mechanisms that cause jet-flame blowout, particularly in the presence of air coflow, are not completely understood. This work examines the role of fuel velocity and air coflow in the blowout phenomenon by examining the transient behavior of the reaction zoneat blowout. The results of video imaging of a lifted methane-air diffusion flame at near blowout conditions are presented. Two types of experiments are described. In the first investigation, a flame is established and stabilized at a known, predetermined downstream location with a constant coflow velocity, and then the fuel velocity is subsequently increased to cause blowout. In the other, an ignition source is used to maintain flame burning near blowout and the subsequent transient behavior to blowout upon removal of the ignition source is characterized. Data from both types of experiments are collected at various coflow and jet velocities. Images are used to ascertain the changes in the leading edge of the reaction zone prior to flame extinction that help to develop a physically-based model to describe jet-flame blowout. The data report that a consistent predictor of blowout is the prior disappearance of the axially oriented flame branch. This is witnessed despite a turbulent flames' inherent variable behavior. Interpretations are also made in the light of analytical mixture fraction expressions from the literature that support the notion that flame blowout occurs when the leading edge reaches the vicinity of the lean-limit contour, which coincides approximately with the conditions for loss of the axially oriented flame structure.
Bipartite Diametrical Graphs of Diameter 4 and Extreme Orders
Authors: Al-Addasi Salah , Al-Ezeh Hasan
Published: February 2008

We provide a process to extend any bipartite diametrical graph of diameter 4 to an S‐graph of the same diameter and partite sets. For a bipartite diametrical graph of diameter 4 and partite sets
U and W, where 2m = |U| ≤ |W|, we prove that 2m
is a sharp upper bound of |W| and construct an S‐graph G(2m, 2m)
in which this upper bound is attained, this graph can be viewed as a generalization of the Rhombic Dodecahedron. Then we show that for any m ≥ 2, the graph G(2m, 2m) is the unique (up to isomorphism) bipartite diametrical graph of diameter 4 and partite sets of cardinalities
2m and 2m, and hence in particular, for m = 3,
the graph G(6, 8)
which is just the Rhombic Dodecahedron is the unique (up to isomorphism) bipartite diametrical graph of such a diameter and cardinalities of partite sets. Thus we complete a characterization of S‐graphs of diameter 4 and cardinality of the smaller partite set not exceeding 6. We prove that the neighborhoods of vertices of the larger partite set of
G(2m, 2m) form a matroid whose basis graph is the hypercube Qm. We prove that any S‐graph of diameter 4 is bipartite self complementary, thus in particular
G(2m, 2m). Finally, we study some additional properties of G(2m, 2m) concerning the order of its automorphism group, girth, domination number, and when being Eulerian.
Physics of Superpulses in Storage Ring Free‐Electron Lasers
Authors: Litvinenko Vladimir N.
Published: February 2008

Contradictory to the widespread perception, storage ring
free‐electron lasers with substantial net gain can generate peak lasing power reaching
GW levels in the so‐called superpulse mode. This power level is sufficient for studies of
nonlinear processes and efficient intracavity harmonic generation. This letter describes the physics
of the superpulses and a phase‐space refreshment in the electron beam responsible for this phenomenon.
Lie Supergroups Obtained from 3‐Dimensional Lie Superalgebras Associated to the Adjoint Representation and Having a 2‐Dimensional Derived Ideal
Authors: Hernández I. , Peniche R.
Published: February 2008

We give the explicit multiplication law of the Lie supergroups for which
the base manifold is a 3‐dimensional Lie group and whose underlying Lie superalgebra

which satisfies , acts on via the adjoint representation and has
a 2‐dimensional derived ideal.
Structure Theorem for Functionals in the Space 𝔖ω1,ω2′
Authors: Obiedat Hamed M. , Shatanawi Wasfi A. , Yasein Mohd M.
Published: February 2008

We introduce the space of all C∞ functions ϕ such that and are finite for all k ∈ ℕ0, , where ω1 and ω2 are two weights satisfying
the classical Beurling conditions. Moreover, we give a topological
characterization of the space without conditions on the derivatives. For functionals in the dual space , we prove a structure
theorem by using the classical Riesz representation thoerem.
Tubercular Sinus of Labia Majora: Rare Case Report
Authors: Manoj Kela , Soma Mukherjee , Ajay Lunawat , Ashish Agrawal , Rakesh Shishodiya , Paliwal R. V.
Published: February 2008

Tuberculosis of the female external genitalia is unusual and primary infection is rare. We report a 50-year-old female patient admitted to Department to Surgery with swelling over left inguinal area with discharging sinus from labia majora to left inguinal crease which was found to be tubercular sinus on histopathology.
Generalized Solutions of Functional Differential Inclusions
Authors: Machina Anna , Bulgakov Aleksander , Grigorenko Anna
Published: February 2008

We consider the initial value problem for a functional differential inclusion with a Volterra multivalued mapping that is not necessarily decomposable in . The concept of the decomposable hull of a set
is introduced. Using this concept, we define a generalized
solution of such a problem and study its properties. We have
proven that standard results on local existence and continuation
of a generalized solution remain true. The question on the
estimation of a generalized solution with respect to a given
absolutely continuous function is studied. The density principle
is proven for the generalized solutions. Asymptotic properties of
the set of generalized approximate solutions are studied.
Production of Carbon Nanofibers Using a CVD Method with Lithium Fluoride as a Supported Cobalt Catalyst
Authors: Manafi S. A. , Badiee S. H.
Published: February 2008

Carbon nanofibers (CNFs) have been synthesized in high yield (>70%) by catalytic chemical vapor deposition (CCVD) on Co/LiF catalyst using acetylene as carbon source. A novel catalyst support (LiF) is reported for the first time as an alternative for large-scale production of carbon nanofibers while purification process of nanofibers is easier. In our experiment, the sealed furnace was heated at700∘Cfor 0.5 hour (the heating rate was10∘C/min) and then cooled to room temperature in the furnace naturally. Catalytic chemical vapor deposition is of interest for fundamental understanding and improvement of commercial synthesis of carbon nanofibers (CNFs). The obtained sample was sequentially washed with ethanol, dilutes acid, and distilled water to remove residual impurities, amorphous carbon materials, and remaining of catalyst, and then dried at110∘Cfor 24 hours. The combined physical characterization through several techniques, such as high-resolution transmission electron microscope (TEM), scanning electron microscope (SEM), thermogarvimetric analysis (TGA), and zeta-sizer and Raman spectroscopy, allows determining the geometric characteristic and the microstructure of individual carbon nanofibers. Catalytic chemical vapor deposition is of interest for fundamental understanding and improvement of commercial synthesis of carbon nanofibers (CNFs). As a matter of fact, the method of CCVD guarantees the production of CNFs for different applications.
Multisensor Estimation of Mixing Heights over a Coastal City
Authors: Nielsen-Gammon John W. , Powell Christina L. , Mahoney M. J. , Angevine Wayne M. , Senff Christoph , White Allen , Berkowitz Carl , Doran Christopher , Knupp Kevin
Published: February 2008

An airborne microwave temperature profiler (MTP) was deployed during the Texas 2000 Air Quality Study (TexAQS-2000) to make measurements of boundary layer thermal structure. An objective technique was developed and tested for estimating the mixed layer (ML) height from the MTP vertical temperature profiles. The technique identifies the ML height as a threshold increase of potential temperature from its minimum value within the boundary layer. To calibrate the technique and evaluate the usefulness of this approach, coincident estimates from radiosondes, radar wind profilers, an aerosol backscatter lidar, and in situ aircraft measurements were compared with each other and with the MTP. Relative biases among all instruments were generally less than 50 m, and the agreement between MTP ML height estimates and other estimates was at least as good as the agreement among the other estimates. The ML height estimates from the MTP and other instruments are utilized to determine the spatial and temporal evolution of ML height in the Houston, Texas, area on 1 September 2000. An elevated temperature inversion was present, so ML growth was inhibited until early afternoon. In the afternoon, large spatial variations in ML height developed across the Houston area. The highest ML heights, well over 2 km, were observed to the north of Houston, while downwind of Galveston Bay and within the late afternoon sea breeze ML heights were much lower. The spatial variations that were found away from the immediate influence of coastal circulations were unexpected, and multiple independent ML height estimates were essential for documenting this feature.
Assessing Predictability of Cotton Yields in the Southeastern United States Based on Regional Atmospheric Circulation and Surface Temperatures
Authors: Baigorria Guillermo A. , Hansen James W. , Ward Neil , Jones James W. , O’Brien James J.
Published: February 2008

The potential to predict cotton yields up to one month before planting in the southeastern United States is assessed in this research. To do this, regional atmospheric variables that are related to historic summer rainfall and cotton yields were identified. The use of simulations of those variables from a global circulation model (GCM) for estimating cotton yields was evaluated. The authors analyzed detrended cotton yields (1970–2004) from 48 counties in Alabama and Georgia, monthly rainfall from 53 weather stations, monthly reanalysis data of 850- and 200-hPa winds and surface temperatures over the southeast U.S. region, and monthly predictions of the same variables from the ECHAM 4.5 GCM. Using the reanalysis climate data, it was found that meridional wind fields and surface temperatures around the Southeast were significantly correlated with county cotton yields (explaining up to 52% of the interannual variability of observed yields), and with rainfall over most of the region, especially during April and July. The tendency for cotton yields to be lower during years with atmospheric circulation patterns that favor higher humidity and rainfall is consistent with increased incidence of disease in cotton during flowering and harvest periods under wet conditions. Cross-validated yield estimations based on ECHAM retrospective simulations of wind and temperature fields forced by observed SSTs showed significant predictability skill (up to 55% and 60% hit skill scores based on terciles and averages, respectively). It is concluded that there is potential to predict cotton yields in the Southeast by using variables that are forecast by numerical climate models.
Retrieval of Raindrop Size Distribution from Simulated Dual-Frequency Radar Measurements
Authors: Munchak S. Joseph , Tokay Ali
Published: February 2008

Observations of raindrop size distributions (DSDs) have validated the use of three-parameter distribution functions in representing the observed spectra. However, dual-frequency radar measurements are limited to retrieving two independent parameters of the DSD, thus requiring a constraint on a three-parameter distribution. In this study, disdrometer observations from a variety of climate regions are employed to develop constraints on the gamma distribution that are optimized for dual-frequency radar rainfall retrievals. These observations are composited by reflectivity, and then gamma parameters are fit to the composites. The results show considerable variability in shape parameter between regions and within a region at different reflectivities. Most notable is that oceanic regions exhibit maxima in shape parameter at 13.6-GHz reflectivities between 40 and 50 dBZ, in contrast to continental regions. The shape parameter and slope parameter of all composite DSDs are poorly correlated. Thus, constraints of a constant shape parameter or shape parameter–slope parameter relationship are inadequate to represent the observed variability. However, the shape and slope parameters are highly correlated at a given reflectivity. Constraints of a fixed shape parameter and relationships between a shape parameter m and slope parameter Λ, both of which are given as functions of 13.6-GHz reflectivity, are applied to retrieve rain rate, liquid water content, and mean mass diameter from the composites. The m–Λ relationships perform best at high reflectivity (dBZ13.6 > 35), whereas the fixed shape parameter generally results in lower error at medium and low reflectivities (dBZ13.6 < 35). All calculations have been made under the assumption that the reflectivity measurements have been corrected for attenuation.
Turbulent Flux Transfer over Bare-Soil Surfaces: Characteristics and Parameterization
Authors: Yang Kun , Koike Toshio , Ishikawa Hirohiko , Kim Joon , Li Xin , Liu Huizhi , Liu Shaomin , Ma Yaoming , Wang Jieming
Published: February 2008

Parameterization of turbulent flux from bare-soil and undercanopy surfaces is imperative for modeling land–atmosphere interactions in arid and semiarid regions, where flux from the ground is dominant or comparable to canopy-sourced flux. This paper presents the major characteristics of turbulent flux transfers over seven bare-soil surfaces. These sites are located in arid, semiarid, and semihumid regions in Asia and represent a variety of conditions for aerodynamic roughness length (z0m; from <1 to 10 mm) and sensible heat flux (from −50 to 400 W m−2). For each site, parameter kB−1 [=ln(z0m/z0h), where z0h is the thermal roughness length] exhibits clear diurnal variations with higher values during the day and lower values at night. Mean values of z0h for the individual sites do not change significantly with z0m, resulting in kB−1 increasing with z0m, and thus the momentum transfer coefficient increases faster than the heat transfer coefficient with z0m. The term kB−1 often becomes negative at night for relatively smooth surfaces (z0m ∼ 1 mm), indicating that the widely accepted excess resistance for heat transfer can be negative, which cannot be explained by current theories for aerodynamically rough surfaces. Last, several kB−1 schemes are evaluated using the same datasets. The results indicate that a scheme that can reproduce the diurnal variation of kB−1 generally performs better than schemes that cannot.
Maize Pollen Dispersal under Convective Conditions
Authors: Boehm Matthew T. , Aylor Donald E. , Shields Elson J.
Published: February 2008

The widespread adoption of genetically modified (GM) crops has led to a need to better understand the atmospheric transport of pollen because of concerns over potential cross-pollination between GM and non-GM crops. Maize pollen concentrations were modeled by a modified Lagrangian stochastic (LS) model of the convective boundary layer (CBL) and were compared with concentrations measured by airborne remotely piloted vehicles (RPVs) flown from directly above to 2 km from source fields. The turbulence parameterization in an existing CBL LS model was modified to incorporate the effects of shear-driven turbulence, which has an especially large impact near the surface, where maize pollen is released. The modified model was used to calculate concentrations corresponding to the RPV flight tracks. For the most convective cases, when at least 95% of the pollen came from sources near the RPV flight track for which source strength measurements are available and the results are less sensitive to uncertainty in wind direction since most of the pollen came from directly beneath the flight track, the geometric mean of the ratio between the modeled and measured concentrations was 0.94. When cases with larger contributions from more distant fields were included, the overall geometric mean decreased to 0.43. The scatter of the measured concentrations about the modeled values followed a lognormal distribution. These results indicate that the modified model presented herein can substantially improve the description of the near-source dispersion of heavy particles released near the surface during convective conditions.
Comparison of Gridded Multisatellite Rainfall Estimates with Gridded Gauge Rainfall over West Africa
Authors: Lamptey Benjamin L.
Published: February 2008

Two monthly gridded precipitation datasets of the Global Precipitation Climatology Project (GPCP; the multisatellite product) and the Global Precipitation Climatology Centre (GPCC) Variability Analysis of Surface Climate Observations (VASClimO; rain gauge data) are compared for a 22-yr period, from January 1979 to December 2000, over land areas (i.e., latitudes 4°–20°N and longitudes 18°W–15°E). The two datasets are consistent with respect to the spatial distribution of the annual and seasonal rainfall climatology over the domain and along latitudinal bands. However, the satellite generally overestimates rainfall. The inability of the GPCC data to capture the bimodal rainfall pattern along the Guinea coast (i.e., south of latitude 8°N) is an artifact of the interpolation of the rain gauge data. For interannual variability, the gridded multisatellite and gridded gauge datasets agree on the sign of the anomaly 15 out of the 22 yr (68% of the time) for region 1 (between longitude 5° and 18°W and north of latitude 8°N) and 18 out of the 22 yr (82% of the time) for region 2 (between longitude 5°W and 15°E and north of latitude 8°N). The datasets agreed on the sign of the anomaly 14 out of the 22 yr (64% of the time) over the Guinea Coast. The magnitudes of the anomaly are very different in all years. Most of the years during which the two datasets did not agree on the sign of the anomaly were years with El Niño events. The ratio of the seasonal root-mean-square differences to the seasonal mean rainfall range between 0.24 and 2.60. The Kendall’s tau statistic indicated statistically significant trends in both datasets, separately.
Development of a Global Infrared Land Surface Emissivity Database for Application to Clear Sky Sounding Retrievals from Multispectral Satellite Radiance Measurements
Authors: Seemann Suzanne W. , Borbas Eva E. , Knuteson Robert O. , Stephenson Gordon R. , Huang Hung-Lung
Published: February 2008

A global database of infrared (IR) land surface emissivity is introduced to support more accurate retrievals of atmospheric properties such as temperature and moisture profiles from multispectral satellite radiance measurements. Emissivity is derived using input from the Moderate Resolution Imaging Spectroradiometer (MODIS) operational land surface emissivity product (MOD11). The baseline fit method, based on a conceptual model developed from laboratory measurements of surface emissivity, is applied to fill in the spectral gaps between the six emissivity wavelengths available in MOD11. The six available MOD11 wavelengths span only three spectral regions (3.8–4, 8.6, and 11–12 μm), while the retrievals of atmospheric temperature and moisture from satellite IR sounder radiances require surface emissivity at higher spectral resolution. Emissivity in the database presented here is available globally at 10 wavelengths (3.6, 4.3, 5.0, 5.8, 7.6, 8.3, 9.3, 10.8, 12.1, and 14.3 μm) with 0.05° spatial resolution. The wavelengths in the database were chosen as hinge points to capture as much of the shape of the higher-resolution emissivity spectra as possible between 3.6 and 14.3 μm. The surface emissivity from this database is applied to the IR regression retrieval of atmospheric moisture profiles using radiances from MODIS, and improvement is shown over retrievals made with the typical assumption of constant emissivity.
Analysis of Near-Surface Atmospheric Variables: Validation of the SAFRAN Analysis over France
Authors: Quintana-Seguí P. , Le Moigne P. , Durand Y. , Martin E. , Habets F. , Baillon M. , Canellas C. , Franchisteguy L. , Morel S.
Published: February 2008

Système d’analyse fournissant des renseignements atmosphériques à la neige (SAFRAN) is a mesoscale atmospheric analysis system for surface variables. It produces an analysis at the hourly time step using ground data observations. One of SAFRAN’s main features is that it is based on climatically homogeneous zones and is able to take vertical variations into account. Originally intended for mountainous areas, it was later extended to cover France. This paper focuses on the validation of the extended version. The principle of the analysis is described and its quality was tested for five parameters (air temperature, humidity, wind speed, rainfall, and incoming radiation), using Météo-France’s observation network and data of some well-instrumented stations. Moreover, SAFRAN’s rainfall was compared with another analysis, known as analyse utilisant le relief pour l’hydrométéorologie (Aurelhy). Last, two different versions of SAFRAN were compared for mountain conditions. Temperature and relative humidity were well reproduced, presenting no bias. Wind speed was also well reproduced; however, its bias was −0.3 m s–1. The interpolation from the 6-h time step of the analysis to the 1-h time step was one of the sources of error. The precipitation analysis was robust and not biased; its root-mean-square error was 2.4 mm day−1. This error was mainly due to the spatial heterogeneity of the precipitation within the geographical zones of analysis (1000 km2). The analysis of incoming solar radiation presented some biases, especially in coastal areas. The results of the comparison with some well-instrumented sites were encouraging. SAFRAN is being run operationally at Météo-France on a real-time basis for various applications.
Coopting Liberal Peace-building
Authors: Franks Jason , Richmond Oliver P.
Published: February 2008

The liberal peace framework aims to regulate, govern and empower the individual in a democratic and pluralist milieu. Yet liberal peace-building, even on the scale and depth employed in the international governance of Kosovo, is susceptible to local cooption, particularly where one group can adopt the language of the liberal peace and has strong support and credibility from the international community. This has led to a focus on achieving statehood for Kosovan Albanians, the marginalization of other identity groups and their agendas, and consequently the undermining of the pluralist goals of peace-building with the implicit cooperation of liberal peace-builders. Given Serb opposition to statehood for Kosovo, there is a danger that liberal peace-building will encourage the partition of Kosovo rather than create a pluralist polity. The article illustrates the susceptibility of liberal peace-building to local cooption.
Organizational Learning Mechanisms: The Meaning, Measure, and Implications for School Improvement
Authors: Schechter Chen
Published: February 2008

Purpose: In light of the excessively broad conceptions and nonobservable terms generally characterizing discussions of organizational learning, this study explores the notion of organizational learning in schools through the conceptual framework of organizational learning mechanisms (OLM) and develops a measure of OLM at the elementary school level.

Research Design: Exploratory and confirmatory factor analyses of items are conducted to examine factorial validity. To test the criterion-related validity, the OLM scale is correlated to other established constructs.

Findings: Based on information processing (management science perspective), the four-factor model of OLM in elementary schools is the best fit between the empirical results and the conceptual formulation. The four-factor model includes the following subscales: analyzing information, storing—retrieving—putting to use of information, receiving—disseminating information, and seeking information.

Implications: This study strengthens the feasibility of the OLM framework, based on information processing, to provide a concrete description of organizational learning processes in schools. Using this instrument, schools can assess their own learning cycle, gauging their readiness and increasing their preparation for becoming learning organizations. This study may encourage researchers to explore whether OLM can serve as mediating variable between the system level and the classroom level.
Leadership for Teacher Learning: A Community of Practice Perspective
Authors: Printy Susan M.
Published: February 2008

Purpose: The study is a two-stage inquiry into the influence of high school principals and department chairpersons on the nature of science and mathematics teachers' community of practice participation. Of particular interest is the extent to which formal leaders influence the formation of productive communities of practice and the extent to which leaders affect teachers' professional beliefs and their instructional skills.

Research Design: Using the National Educational Longitudinal Study of 1988 (NELS:88) Second Follow-up Teacher File, measures for the analysis are constructed with the Rasch model. Analysis proceeds in two stages using hierarchical linear modeling. The first stage investigates the importance of school leaders to mathematics and science teachers' participation in productive communities of practice. The second stage looks at the relationship between school leadership and teachers' competence and pedagogical skills, net of the influence of communities of practice.

Findings: Results suggest that both principals and department chairpersons are instrumental in shaping opportunities for teachers to learn in communities of practice. Furthermore, results show that principals are well removed from the instructional concerns of teachers and that department chairpersons might serve to slow down the rate of instructional change.

Conclusions: The connections between school-level leadership and teachers' social learning in their communities of practice have drawn the recent attention of those writing about and conducting research on teacher communities. Researchers, practitioners, and policy makers want to know if school leaders can make a difference in how teachers think about their work and the quality of their instruction in classrooms. Findings offer insight into important links in the causal chain between leadership and student achievement.
Relationships and Resilience
Authors: Gittell Jody Hoffer
Published: February 2008

Organizations in the health care industry and beyond face pressures to lower their costs while maintaining quality, resulting in high levels of stress for their workers. In a nine-hospital study, this article explores the role that relationships play in enabling resilient responses to external pressures and the organizational practices that enable workers to respond in a resilient way when organizational change is required. The article argues that relational coordination—communicating and relating for the purpose of task integration—is a resilient response to external threats that require a coordinated collective response across multiple functions or roles. Findings suggest that workers engage in higher levels of relational coordination when they perceive this type of threat but that the presence of a particular type of high performance work system—a relational work system—greatly strengthens this resilient response.
Toward an Understanding of When Executives See Crisis as Opportunity
Authors: Brockner Joel , James Erika Hayes
Published: February 2008

Whereas it has long been noted that crises may be sources of opportunity for organizations and their constituents, relatively little is known about the conditions under which executives come to perceive crises as opportunity. The authors delineate some factors that affect the tendency of executives to adopt a “crisis as opportunity” mindset as well as the behavioral concomitants of their having done so. The analysis also includes a future research agenda, a consideration of some of the challenges in enacting that agenda, and a few suggested ways to overcome those challenges.
Charisma (Un)Bound
Authors: Glynn Mary Ann , Dowd Timothy J.
Published: February 2008

In this exploratory study, the authors bring together two areas of organizational research—positive organizational scholarship and institutional theory—to examine the discourse of charismatic leadership in the context of organizational change. The authors focus on the case of Martha Stewart and her emotional expressions in two columns she authored in her magazine, Martha Stewart Living. The content analysis revealed that the levels and ratio of leaders' positivity both correlates with and counters organizational change, blunting organizational decline and personal scandal or revealing a human, vulnerable side when times are better. The findings point to the utility of conjoining positive organizational scholarship and institutional theory: Whereas the former shows how charisma unbound can result in emotive leadership, the latter suggests that the bounding of charisma can easily occur in organizations.
Rethinking Reproductive Gifts as Body Projects
Authors: Shaw Rhonda
Published: February 2008

In New Zealand, ovarian egg donation and surrogate pregnancy arrangements are often viewed through the interpretative lens of altruism and reproductive gift-giving. However, gift terminology does not represent the narrative accounts of all women who have participated in donor-assisted conception strategies. Drawing on interview data with New Zealand women, this article deals with accounts from donors who see their donative acts not so much as gifts, but as projects of the self, or as events that serve to mark out new beginnings in their lives.
`Rude Boys': The Homosexual Eroticization of Class
Authors: Johnson Paul
Published: February 2008

Since 2002, the`chav' has become a ubiquitous symbol of class difference in Britain. Simultaneously, a heterogeneous industry has appropriated `chav culture' in order to market a range of products and services orientated to gay men. In this article I explore some of the representations employed by this industry to argue that they function within a symbolic economy in which the chav is positioned as a subject lacking any intrinsic worth. However, while representations continually impute a lack of value to such subjects, it is precisely this lack which is converted into symbolic capital to be bought and sold.The effect of such representation is performative since it both constructs and inscribes subject positions in social space. In conclusion, I argue that a form of symbolic violence is created by such representation through the legitimacy it lends to normative conceptions about, what become imagined as,`real' people.
Does Adolescent Affect Impact Adult Social Integration? Evidence from the British 1946 Birth Cohort
Authors: Hatch Stephani L. , Wadsworth Michael E.J.
Published: February 2008

Using data from the MRC National Survey of Health and Development (the British 1946 birth cohort), we take a life course approach with a sociology of mental health framework to examine the relationship between adolescent affect and adult social integration. The results suggest that being observed as anxious or sad in adolescence has a long-term effect on adult social integration.These associations are not explained by adult mental health or socioeconomic status, for the most part.The results demonstrate support for social selection processes between adolescent mental health and adult social outcomes and suggest a disparate effect of type of adolescent affect on adult social outcomes.
Chesucristo
Authors: Kunzle David
Published: February 2008

Cuba and a few “heretical” interpreters of scripture have seen Jesus in the context of armed struggle against the Roman occupiers. With the Gospels, Jesus was largely disarmed. In the generation since Che Guevara's death, Che has become similarly disarmed—associated with the struggle for social justice and peace rather than with revolutionary violence and the gun. The world-famous Korda photograph, with its expression of a serene visionary, has lent itself to this pacification. Meanwhile, many of the attributes of Jesus and events from his Passion have been fused with the iconic Che images: the three-letter name (IHS = CHE), star, halo, stigmata, crown of thorns, crucifixion, Deposition/Pietà, etc. The Anglican Church has done the reverse: fused a Jesus face with that of Che. Is the left trying to recover a Jesus stolen by the right?
International Links to Early Socialism in Colombia
Authors: Vanegas Isidro
Published: February 2008

The first decades of the twentieth century produced an enormous shift in Colombian political sensibilities, political discourse, and forms of political expression. The relationship of Colombian socialism in its most dynamic stage (1926—1930) with the Communist International was characterized by both sympathy and distance because its desire to become part of the international communist movement sometimes contradicted its commitments to a rich local political tradition. Colombian socialists eventually established ties with the Comintern in a roundabout way, but the ideological direction it offered was difficult to assimilate to the ideological substrate of militants and leaders, in which Christian values, liberal practices, and artisanal traditions mixed.