bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lasp-1 binds to non-muscle F-actin in vitro and is localized within multiple sites of dynamic actin assembly in vivo
Authors: Chew Catherine S. , Chen Xunsheng , Parente John A. , Tarrer Shannan , Okamoto Curtis , Qin Hai-Yen 
Published: November 2002

Lasp-1 has been identified as a signaling molecule that is phosphorylated upon elevation of [cAMP]i in pancreas, intestine and gastric mucosa and is selectively expressed in cells within epithelial tissues. In the gastric parietal cell, cAMP-dependent phosphorylation induces the partial translocation of lasp-1 to the apically directed F-actin-rich canalicular membrane, which is the site of active HCl secretion. Lasp-1 is an unusual modular protein that contains an N-terminal LIM domain, a C-terminal SH3 domain and two internal nebulin repeats. Domain-based analyses have recently categorized this protein as an epithelial representative of the nebulin family, which also includes the actin binding, muscle-specific proteins,nebulin, nebulette and N-RAP.In this study, we show that lasp-1 binds to non-muscle filamentous (F)actin in vitro in a phosphorylation-dependent manner. In addition, we provide evidence that lasp-1 is concentrated within focal complexes as well as in the leading edges of lamellipodia and the tips of filopodia in non-transformed gastric fibroblasts. In actin pull-down assays, the apparent Kd of bacterially expressed his-tagged lasp-1 binding to F-actin was 2 μM with a saturation stoichiometry of ∼1:7. Phosphorylation of recombinant lasp-1 with recombinant PKA increased the Kd and decreased the Bmax for lasp-1 binding to F-actin. Microsequencing and site-directed mutagenesis localized the major in vivo and in vitro PKA-dependent phosphorylation sites in rabbit lasp-1 to S99 and S146. BLAST searches confirmed that both sites are conserved in human and chicken homologues. Transfection of lasp-1 cDNA encoding for alanine substitutions at S99 and S146, into parietal cells appeared to suppress the cAMP-dependent translocation of lasp-1 to the intracellular canalicular region. In gastric fibroblasts, exposure to the protein kinase C activator, PMA, was correlated with the translocation of lasp-1 into newly formed F-actin-rich lamellipodial extensions and nascent focal complexes. Since lasp-1 does not appear to be phosphorylated by PKC,these data suggest that other mechanisms in addition to cAMP-dependent phosphorylation can mediate the translocation of lasp-1 to regions of dynamic actin turnover. The localization of lasp-1 to these subcellular regions under a range of experimental conditions and the phosphorylation-dependent regulation of this protein in F-actin rich epithelial cells suggests an integral and possibly cell-specific role in modulating cytoskeletal/membrane-based cellular activities.
Spatial regulation of the guanine nucleotide exchange factor Lte1 inSaccharomyces cerevisiae
Authors: Jensen Sanne , Geymonat Marco , Johnson Anthony L. , Segal Marisa , Johnston Leland H. 
Published: November 2002

In budding yeast, activation of the small Ras-like GTPase Tem1 triggers exit from mitosis and cytokinesis. Tem1 is regulated by Bub2/Bfa1, a two-component GTPase-activating protein (GAP), and by Lte1, a putative guanine nucleotide exchange factor. Lte1 is confined to the bud cortex, and its spatial separation from Tem1 at the spindle pole body (SPB) is important to prevent untimely exit from mitosis. The pathways contributing to Lte1 asymmetry have not been elucidated. Here we show that establishment of Lte1 at the cortex occurs by an actin-independent mechanism, which requires activation of Cdc28/Cln kinase at START and Cdc42, a key regulator of cell polarity and cytoskeletal organisation. This defines a novel role for Cdc42 in late mitotic events. In turn, dissociation of Lte1 from the cortex in telophase depends on activation of the Cdc14 phosphatase. Ectopic expression of Cdc14 at metaphase results in premature dephosphorylation of Lte1 coincident with its release from the cortex. In vitro phosphatase assays confirm that Lte1 is a direct substrate for Cdc14. Our results suggest that the asymmetry in Lte1 localisation is imposed by Cdc28-dependent phosphorylation.Finally, we report a mutational analysis undertaken to investigate intrinsic Lte1 determinants for localisation. Our data suggest that an intrameric interaction between the N-and C-terminal regions of Lte1 is important for cortex association.
Towards quantifying droplet clustering in clouds
Authors: Shaw R. A. , Kostinski A. B. , Larsen M. L. 
Published: November 2002

AbstractDroplet positions in atmospheric clouds are random but possibly correlated on some scales. This ‘clustering’ must be quantified in order to account for it in theories of cloud evolution and radiative transfer. Tools as varied as droplet concentration power spectrum, Fishing test, and fractal correlation analysis have been used to describe the small‐scale nature of clouds, and it has been difficult to compare conclusions systematically. Here we show, by using the correlation‐fluctuation theorem and the Wiener–Khinchin theorem, that all of these measures can be related to the pair‐correlation function. It is argued that the pair‐correlation function is ideal for quantifying droplet clustering because it contains no scale memory and because of its quantitative link to the Poisson process. Copyright © 2002 Royal Meteorological Society
Extratropical low‐frequency variability as a low‐dimensional problem. II: Stationarity and stability of large‐scale equilibria
Authors: D'andrea Fabio 
Published: November 2002

AbstractStationarity and stability properties of large‐scale persistent anomalies in the northern hemisphere are addressed. The low‐order model developed in Part I is used for this purpose. It was obtained as the projection of a three‐level quasi‐geostrophic system on the ten leading empirical orthogonal functions. Three global quasi‐ stationary states are identified, which represent the Arctic high and the positive and negative phases of the main teleconnections (Pacific North American and North Atlantic oscillation). The quasi‐stationary solutions have only a partial correspondence to the weather regimes found in Part I. Stability analysis shows a growing mode that describes an oscillation between the two phases of the teleconnections. The negative teleconnection state is also shown to be much more stable than the other two. Possible decay mechanisms are also discussed. Copyright © 2002 Royal Meteorological Society
Intercomparison and evaluation of cumulus parametrizations under summertime midlatitude continental conditions
Authors: Xie Shaocheng , Xu Kuan‐Man , Cederwall Richard T. , Bechtold Peter , Genio Anthony D. Del , Klein Stephen A. , Cripe Douglas G. , Ghan Steven J. , Gregory David , Iacobellis Sam F. , Krueger Steven K. , Lohmann Ulrike , Petch Jon C. , Randall David A. , Rotstayn Leon D. , Somerville Richard C. J. , Sud Yogesh C. , Salzen Knut Von , Walker Gregory K. , Wolf Audrey , Yio J. John , Zhang Guang Jun , Zhang Minghua 
Published: November 2002

AbstractThis study reports the Single‐Column Model (SCM) part of the Atmospheric Radiation Measurement (ARM)/the Global Energy and Water Cycle Experiment (GEWEX) Cloud System Study (GCSS) joint SCM and Cloud‐Resolving Model (CRM) Case 3 intercomparison study, with a focus on evaluation of cumulus parametrizations used in SCMs. Fifteen SCMs are evaluated under summertime midlatitude continental conditions using data collected at the ARM Southern Great Plains site during the summer 1997 Intensive Observing Period. Results from ten CRMs are also used to diagnose problems in the SCMs.It is shown that most SCMs can generally capture well the convective events that were well‐developed within the SCM domain, while most of them have difficulties in simulating the occurrence of those convective events that only occurred within a small part of the domain. All models significantly underestimate the surface stratiform precipitation. A third of them produce large errors in surface precipitation and thermodynamic structures. Deficiencies in convective triggering mechanisms are thought to be one of the major reasons. Using a triggering mechanism that is based on the vertical integral of parcel buoyant energy without additional appropriate constraints results in overactive convection, which in turn leads to large systematic warm/dry biases in the troposphere. It is also shown that a non‐penetrative convection scheme can underestimate the depth of instability for midlatitude convection, which leads to large systematic cold/moist biases in the troposphere.SCMs agree well quantitatively with CRMs in the updraught mass fluxes, while most models significantly underestimate the downdraught mass fluxes. Neglect of mesoscale updraught and downdraught mass fluxes in the SCMs contributes considerably to the discrepancies between the SCMs and the CRMs. In addition, uncertainties in the diagnosed mass fluxes in the CRMs and deficiencies with cumulus parametrizations are not negligible.Similar results are obtained in the sensitivity tests when different forcing approaches are used. Finally, sensitivity tests from an SCM indicate that its simulations can be greatly improved when its triggering mechanism and closure assumption are improved. © Royal Meteorological Society, 2002. J. C. Petch's contribution is Crown copyright.
Maslov's method for stationary hydrostatic mountain waves
Authors: Broutman Dave , Rottman James W. , Eckermann Stephen D. 
Published: November 2002

AbstractThe ray solution for stationary hydrostatic mountain waves has a singularity along the vertical axis directly over the mountain. We use Maslov's method to improve the ray prediction. The ray solution is determined in the wave‐number domain and is then mapped by inverse Fourier transform to give a spatial description of the wave field that approximates the linear solution over the mountain and elsewhere. We develop Maslov's method for a medium with a height‐dependent mean wind and mean buoyancy, and we compare it with the traditional transform method and with the results of a numerical simulation. Copyright © 2002 Royal Meteorological Society
Multi‐scale description of a Sahelian synoptic weather system representative of the West African monsoon
Authors: Redelsperger J.‐L. , Diongue A. , Diedhiou A. , Ceron J.‐P. , Diop M. , Gueremy J.‐F. , Lafore J.‐P. 
Published: November 2002

AbstractA reference case of a Sahelian weather system observed during the Hydrological Atmospheric Pilot Experiment, HAPEX‐SAHEL, in August 1992, is described from a seasonal viewpoint as well as from synoptic and convective system viewpoints. It is shown that the case‐study is representative of the climatology at all these scales and presents many interacting scales and physical processes. At intraseasonal scale, the monsoon onset is characterized by an abrupt shift of precipitation together with a latitudinal migration of the African easterly jet (AEJ) and convection. At the month and day scales, the convective activity occurs in an apparent zonal break of the tropical easterly jet. The month of August 1992 exhibits intense synoptic activity. The vorticity field is characterized by northerly (dry) and southerly (wet) components located at 850 hPa on each side of the AEJ. Their intraseasonal modulation on a period of 20 to 40 days leads to active and break phases of the synoptic activity. Around 21 August, the 700 hPa vorticity field features the propagation of a typical easterly wave with a westward propagation of a cyclonic circulation followed by an anticyclonic circulation. Convective activity occurs mainly ahead of the 700 hPa vorticity maximum with the formation of a squall line on Aïr mountains propagating south‐westward at 15 m s−1. The convective system propagates about twice as fast as the vortex core, in contrast with the convection in the European Centre for Medium‐Range Weather Forecasts re‐analysis which stays in phase with the vorticity. The squall line corresponds to the largest contributor to the systems passing in August 1992 over the HAPEX‐SAHEL region; its environmental conditions and its effects on the atmosphere including the surface parameters are presented. Copyright © 2002 Royal Meteorological Society
Response of the atmosphere–ocean mixed‐layer system to anomalous ocean heat‐flux convergence
Authors: Sutton R. , Mathieu P.‐P. 
Published: November 2002

AbstractWe investigate the role of the extratropical oceans in climate variability. Rather than following the traditional approach of studying the atmospheric response to prescribed sea‐surface‐temperature (SST) anomalies, we focus on the role of anomalous ocean heat transport. We employ an atmosphere model coupled to a fixed‐depth (‘slab’) ocean mixed‐layer model, forced by a field of ocean heat‐flux convergence (OHFC). We study the response of this coupled atmosphere–ocean mixed‐layer system to an idealized OHFC anomaly.We find that the OHFC forcing is mainly balanced by anomalous surface latent‐heat flux, i.e. enhanced evaporation. Notably, the anomalous SST is not co‐located with the forcing, nor with the anomalous air–sea flux, nor with the anomalous diabatic heating. Contrary to conventional wisdom, in our experiment the influence of the extratropical ocean on the atmosphere is not manifest primarily in an SST signature. The anomalous diabatic heating is associated with a downstream surface low‐pressure anomaly, in line with the simple theory of the steady response to extratropical heating. Transient‐eddy anomalies play only a minor role. The principal SST anomaly appears to be a passive response to this anomalous atmospheric flow.Our results suggest that the traditional narrow focus on SST as the key variable involved in ocean–atmosphere interaction may offer only a limited, perhaps even misleading, guide to the influence of the extratropical oceans on climate variability. Copyright © 2002 Royal Meteorological Society
The cold Arctic winter 1995/96 as observed by GOME and HALOE: Tropospheric wave activity and chemical ozone loss
Authors: Weber M. , Eichmann K.‐U. , Wittrock F. , Bramstedt K. , Hild L. , Richter A. , Burrows J. P. , Üller R. M 
Published: November 2002

AbstractThe Global Ozone Monitoring Experiment aboard the European Remote Sensing Satellite ERS‐2 was the only satellite instrument measuring total ozone on a near‐global scale during the extremely cold Arctic winter 1995/96. Extremely low total ozone was observed within the Arctic vortex during February and March. The lowest value in this winter was 178 DU (Dobson units) over Greenland on 19 February, which was about 160 DU below the February Arctic vortex mean of total ozone. Although severe chemical ozone destruction occurred in late winter 1995/96, the extremely low values in total ozone observed after the middle of February were, in all cases, related to mini‐hole events, where large horizontal divergent transport of ozone from the lower‐stratospheric layer above a high tropopause rapidly reduced the total column in a localized region. The observed total‐ozone minima were located near the vortex edge and in the region of minimum lower‐stratospheric temperatures that were, in selected cases, sufficiently low for the formation of polar stratospheric ice clouds (PSC type II) below 188 K at the isentropic level of 475 K. Coincident ozone profile observations in early March from the Halogen Occultation Experiment on the Upper Atmosphere Research Satellite indicate that the strong chemical ozone loss was mainly confined to the polar vortex region, and that the extremely low total‐ozone values below 250 DU were mainly caused by short‐term reversible dynamical reductions superimposed upon chemical ozone loss occurring on longer timescales. Enhanced OClO and chlorine activation, due to strong tropospheric wave activity associated with an ozone mini‐hole event, was only observed in early March following a stratospheric temperature drop below the ice frost point. In general, however, the observation of very low total ozone in mini‐hole events does not necessarily point to significant additional chemical depletion. Copyright © 2002 Royal Meteorological Society
The interaction between model resolution, observation resolution and observation density in data assimilation: A one‐dimensional study
Authors: Liu Z.‐Q. , Rabier F. 
Published: November 2002

AbstractIn this paper, the optimal configurations of model resolution, observation resolution and observation density are investigated in a simple one‐dimensional framework. In this context, the representativeness error is formalized and estimated before being used in the analysis‐error formulation. Some optimal and suboptimal assimilation‐schemes, differing from different approximations of observation‐error covariance and observation operator, are compared. The optimal observation‐extent is determined as a function of model resolution. Increasing the observation density is usually beneficial, except for suboptimal schemes similar to the ones used in operational practice. The impact of thinning the observations with correlated error is also studied from a suboptimal viewpoint. Copyright © 2002 Royal Meteorological Society
Synthesis and study of new polyamides with side oxadiazole rings
Authors: Bruma M. , Hamciuc E. , Schulz B. , Kopnick T. , Kaminorz Y. , Robison J. 
Published: November 2002

AbstractA series of six new aromatic polyamides with side oxadiazole rings has been synthesized by polycondensation reaction of aromatic diamines containing pendent substituted oxadiazole groups with a silicon‐containing diacid chloride [namely, bis(p‐chlorocarbonyl‐phenylene)diphenylsilane] or with a fluorine‐containing diacid chloride [namely, hexafluoroisopropylidene‐bis(p‐benzoyl chloride)]. All polymers were easily soluble in amidic solvents, such as N‐methylpyrrolidinone and dimethylformamide, and gave thin transparent films by casting such solutions. Very thin coatings were deposited onto silicon wafers and exhibited smooth, pinhole‐free surfaces in atomic force microscopy investigations. The polymers showed high thermal stability, with decomposition temperature >400°C. Some of them did exhibit a glass transition, in the range 152–276°C, with a reasonable interval between glass transition and decomposition. Four of these polymers showed blue photoluminescence, in the range 460–480 nm, which makes them promising candidates for future use as high‐performance materials in the construction of light‐emitting devices. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 714–721, 2003
M‐sequence‐based M‐ary/SS/CDMA system using blocked viterbi decoding and accurate SNIR measurement techniques for high‐bit‐rate wireless communication systems
Authors: Ito Takumi , Sampei Seiichi , Morinaga Norihiko 
Published: November 2002

AbstractThis paper discusses the application of M‐ary/SS (M‐ary/Spread Spectrum) to DS/CDMA (Direct Sequence/Code Division Multiple Access) system. M‐ary/SS system can realize a high‐bit‐rate transmission while maintaining a high processing gain. On the other hand, the system requires the same number of correlators as the number of candidate spreading codes. In this study, the orthogonal code based on M‐sequence is used as the spreading sequence, in order to simplify the correlator configuration. In addition, an algorithm is proposed to realize the error‐correcting code and the transmit power control, which are necessary in DS/CDMA system. As a result of analysis by computer simulation, it is shown that the proposed system has an excellent transmission performance. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(3): 80–91, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10012
1.28 Tbit/s—70‐km OTDM femtosecond‐pulse transmission using third‐ and fourth‐order simultaneous dispersion compensation with a phase modulator
Authors: Yamamoto Takashi , Tamura Kohichi R. , Nakazawa Masataka 
Published: November 2002

AbstractBy means of the higher‐order dispersion compensation technique using a phase modulator, a 70‐km transmission experiment with 1.28 Tbit/s OTDM (Optical Time Domain Multiplexing) signals has been successfully conducted for the first time. The details are reported in this paper. The 1.28 Tbit/s signal is obtained by 64‐fold multiplexing of 10 Gbit/s signals with additional polarization multiplexing. For the signal pulse with a pulse width of 380 fs prior to transmission, a linear chirp is imparted and then a cosine phase modulation with an appropriate amplitude and the timing is set in such a way that the imparted chirp is opposite to the chirps caused by the third‐ and fourth‐order dispersion in the transmission path. In this way, the waveform distortion of the signal due to the third‐ and fourth‐order dispersion can be suppressed simultaneously. The pulse widening of the signal after transmission over 70 km is only 20 fs. Hence, an error rate of less than 1 × 10−9can be realized over the entire channel (10 Gbit/s–128 channels after multiplexing separation). © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(3): 68–79, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10028
Communication quality control scheme by using priority control mechanism for ethernet‐based wireless LANs
Authors: Saitoh Kazuyoshi , Inoue Yasuhiko , Iizuka Masataka , Morikura Masahiro 
Published: November 2002

AbstractA method that realizes CoS (Class of Service) control in Ethernet is communication quality control based on the user priority specified by IEEE 802.1D Annex H. This paper presents a result of investigation of CoS control scheme in IEEE 802.11 system, which is Ethernet wireless LAN standardized by IEEE 802 Committee. An evaluation is also tried by computer simulation, and it is found that the bounded delay time and the bandwidth guarantee are realized, providing the best effort with higher priority in the contention control. It is also shown that the proposed scheme can be used as protection against the user who sends/receives a large amount of data, constraining the bandwidth. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(3): 53–67, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10029
Bi‐soliton pulse in a dispersion‐managed optical transmission system and its application
Authors: Nonaka Yasumichi , Inoue Takashi , Maruta Akihiro 
Published: November 2002

AbstractIn this paper, the mutual interaction of adjacent pulses is studied as a cause for degradation of the transmission quality of a dispersion‐managed (DM) soliton. It is shown that the variation of the pulse spacing due to the mutual interaction between two DM solitons can be made extremely small by appropriately selecting the incident pulse spacing and the transmission line parameters. Next, the averaging method is applied to two DM solitons in the parameter region in which the effect of this mutual interaction becomes extremely small. It is shown that there exists a bi‐soliton as a steady solution with two main lobes. Its nature is discussed in detail. Further, a novel transmission line coding scheme using this bi‐soliton is worked out and a method to reduce the interpulse mutual interaction is proposed. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(3): 44–52, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10035