bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of extracellular matrix proteins on macrophage differentiation, growth, and function: Comparison of liquid and agar culture systems
Authors: Armstrong Jason W. , Chapes Stephen K. 
Published: June 2005

AbstractBoth spaceflight and skeletal unloading suppress the haematopoietic differentiation of macrophages (Sonnenfeld et al., Aviat. Space Environ. Med., 61:648–653, 1990; Armstrong et al., J. Appl. Physiol., 75:2734–2739, 1993). The mechanism behind this reduction in haematopoiesis has yet to be elucidated. However, changes in bone marrow extracellular matrix (ECM) may be involved. To further understand the role of ECM products in macrophage differentiation, we have performed experiments evaluating the effects of fibronectin, laminin, collagen type I, and collagen type IV on macrophage development and function. Bone marrow–derived macrophages cultured on four different ECM substrates in liquid culture medium showed less growth than those cultured on plastic. Significant morphological differences were seen on each of the substrates used. Phenotypically and functionally, as measured by class II major histocompatibility molecule (MHCII) expression, MAC‐2 expression, and the secretion of interleukin‐6 (IL‐6) and tumor necrosis factor‐α (TNF‐α), these macrophages were similar. In contrast, bone marrow—derived macrophages cultured in suspension, using agar, showed no difference in growth when exposed to ECM proteins. However, IL‐6 and TNF‐α secretion was affected by fibronectin, laminin, collagen type I, and collagen type IV in a concentration‐dependent manner. We conclude that the ECM products fibronectin, laminin, collagen type I, and collagen type IV have profound effects on macrophage development and function. Additionally, we suggest that an ECM‐supplemented agar culture system provides an environment more analogous to in vivo bone marrow than does a traditional liquid culture system. © 1994 Wiley‐Liss, Inc.
Pattern of cell proliferation in the early stages of arm regeneration in the feather star Antedon mediterranea
Authors: Candia Carnevali M. Daniela , Bonasoro Francesco , Lucca Elisa , Thorndyke Michael C. 
Published: June 2005

AbstractArm regeneration in the crinoid echinoderm Antedon mediterranea can provide a very useful model for studying regenerative development. This process can be described as an epimorphic process in which new structures develop from migratory actively proliferating cells. Both the repair and the regenerative phases are due to this fundamental mechanism, which is the only way of recruiting cells to form the cicatricial layer and the blastema. In order to identify the source, the proliferation sites and the recruitment times of these cells, cell proliferation was monitored by employing an immunocytochemical system to detect the thymidine analogue bromodeoxyuridine (BrdU) incorporated by S‐phase cells of the regenerating tissues. On the basis of BrdU incorporation the actively proliferating elements can be identified both close and far from the amputation 1) in the populations of migratory cells which are produced at the level of the brachial nerve and the coelomic wall and 2) in the coelomic epithelium itself. These structures are preferential sources of new cells and give a differential contribution during the repair and the regenerative phases in terms of potential of cell proliferation. © 1995 Wiley‐Liss, Inc.
Assembly of somatic histone H1 onto chromatin during bovine early embryogenesis
Authors: Smith Lawrence C. , Meirelles Flávio V. , Bustin Michael , Clarke Hugh J. 
Published: June 2005

AbstractWe have examined the distribution of somatic histone H1 in bovine oocytes and preimplantation embryos, using an antibody that recognizes histone H1 subtypes present in somatic cells. Immunoreactive H1 was not detectable on the chromosomes of metaphase II of meiosis nor in the nuclei of early cleavage‐stage embryos. In most embryos, immunoreactive H1 was assembled onto embryonic chromatin during the fourth to sixth cell cycle after fertilization. No immunoreactive somatic histone H1 was detected, however, when embryos were incubated in the presence of α‐amanitin beginning early during the fourth cell cycle. These results indicate that somatic subtypes of histone H1 are assembled onto embryonic chromatin in a developmentally regulated manner that requires embryonic transcription. Aphidicolin, an inhibitor of DNA replication, also inhibited the assembly of somatic histone H1 onto chromatin when present at early stages of the 4th cell cycle. It is suggested that, because the bulk of histone gene expression in proliferating cells occurs during DNA replication, expression of genes encoding immunoreactive H1 is inhibited in embryos blocked before or soon after entering the S‐phase. These findings on the control of somatic histone H1 assembly onto chromatin in cattle show a remarkable similarity to those found in the mouse. Such evolutionary conservation suggests that the somatic histone H1 complement of chromatin may regulate critical aspects of chromatin activity during mammalian oogenesis or early embryogenesis. © 1995 Wiley‐Liss, Inc.
Quantifying random measurement errors in Voluntary Observing Ships' meteorological observations
Authors: Kent Elizabeth C. , Berry David I. 
Published: June 2005

AbstractEstimates of the random measurement error contained in surface meteorological observations from Voluntary Observing Ships (VOS) have been made on a 30° area grid each month for the period 1970 to 2002. Random measurement errors are calculated for all the basic meteorological variables: surface pressure, wind speed, air temperature, humidity and sea‐surface temperature. The random errors vary with space and time, the quality assurance applied and the types of instrument used to make the observations. The estimates of random measurement error are compared with estimates of total observational error, which includes uncertainty due both to measurement errors and to observational sampling. In tropical regions the measurement error makes a significant contribution to the total observational error in a single observation, but in higher latitudes the sampling error can be much larger. Copyright © 2005 Royal Meteorological Society
Impacts of in situ and additional satellite data on the accuracy of a sea‐surface temperature analysis for climate
Authors: Reynolds Richard W. , Zhang Huai‐Min , Smith Thomas M. , Gentemann Chelle L. , Wentz Frank 
Published: June 2005

AbstractAdditional in situ and satellite data improve the accuracy of a blended (in situ and satellite) sea‐surface temperature (SST) analysis using optimum interpolation (OI). Two studies were conducted to evaluate the impacts of in situ and additional satellite data. One study evaluated the adequacy of the recent in situ network. Because of the high coverage of satellite data, in situ data used in the analysis tends to be overwhelmed by satellite data. Thus, the most important role of the in situ data in the analysis is to correct large‐scale satellite biases. Simulations with different buoy densities showed the need for at least two buoys on a 10° spatial grid. This will ensure that satellite biases do not exceed 0.5 °C. Using this criterion, regions were identified where additional buoys are needed.A second study evaluated the impact of satellite SST retrievals from the tropical rainfall measuring mission microwave imager (TMI) on the OI analysis. The present version only uses infrared satellite data from the advanced very high resolution radiometer (AVHRR) instrument. The results of the intercomparisons showed that both AVHRR and TMI data have biases that must be corrected for climate studies. The addition of TMI data clearly improved the OI analysis accuracy without bias correction, but was less significant when bias correction was used. However, there are areas of the ocean with limited in situ data and restricted AVHRR coverage due to cloud cover, and the use of both TMI and AVHRR should improve the accuracy of the analysis in those areas. Copyright © 2005 Royal Meteorological Society
Objective analyses of sea‐surface temperature and marine meteorological variables for the 20th century using ICOADS and the Kobe Collection
Authors: Ishii Masayoshi , Shouji Akiko , Sugimoto Satoshi , Matsumoto Takanori 
Published: June 2005

AbstractData for the 20th century from the International Comprehensive Ocean and Atmosphere Data Set and the Kobe Collection have been used as input data for global objective analyses of sea‐surface temperatures (SSTs) and other marine meteorological variables. This study seeks a better understanding of the historical marine meteorological data and an evaluation of the quality of the data in the Kobe Collection. Objective analyses yield gridded data that are less noisy than observed data, which facilitates handling of historical data. The observed data determine the quality of the objective analyses, and quality control specified for historical data is incorporated into the objective analysis to reduce artificial errors. The objective analyses are based on optimum interpolation and reconstruction with empirical orthogonal functions. The final database produced in this study not only contains analysed values, but also analysis errors and data distributions at each time step of the objective analyses.The analysis database contains ample information on historical observations, as well as signals of marine climate variations during the century. Time series of global mean marine temperatures and cloud cover include trends linked to global warming, and local peaks appear commonly in all the time series around the 1940s. Sea‐level pressure and sea‐surface wind fields show significant linear trends at high latitudes and over the North Pacific Ocean respectively. These trends seem to be artificial. An SST analysis used widely in climatological studies was verified against HadISST from the Hadley Centre and an SST analysis derived from satellite and in situ observations. El Niño and southern oscillation indices for the century are successfully reproduced, even though observations in the tropics are much rarer before 1950 than after 1950. Copyright © 2005 Royal Meteorological Society
Assessing bias corrections in historical sea surface temperature using a climate model
Authors: Folland Chris 
Published: June 2005

AbstractAnalyses of simulations of variations in global and large‐regional land surface air temperature (LSAT) for 1872–1998 using the HadAM3 atmospheric general circulation model are reported. The analyses are designed to test the accuracy of bias corrections to sea‐surface temperature (SST) used in the Hadley Centre's global sea ice and SST (GISST3.1) data set, the more recent Hadley Centre sea ice and SST (HadISST) data set, and in the underlying Met Office historical SST (MOHSST and HadSST1) data sets. The tests are important because SST corrections considerably affect estimates of the magnitude of global warming since the late 19th century. Two ensembles of simulations were created using GISST3.1 as the lower boundary condition. The first ensemble, of six integrations, was forced using GISST with bias‐corrections applied from 1871 until 1941, and was continued with no bias corrections to 1998. A second ensemble of four integrations, for 1871 to 1941, was forced with uncorrected GISST data. Simulations with uncorrected GISST show a substantial and often highly significant cold bias in simulated global and large‐regional annual mean LSAT changes before 1942 relative to a 1946–65 reference period. By contrast, corrected SST data led to simulations of LSAT changes that are generally insignificantly different from those of observed LSAT in most regions before 1942. Tests on extratropical hemispheric scales generally validate the seasonal variation of the bias corrections, though less clearly before 1890 in some seasons. Issues about the quality of the LSAT data are raised by the results in a couple of regions. Over Australia, the model may have reconstructed LSAT changes using bias‐corrected GISST with greater accuracy than the observations before about 1910. © Crown Copyright 2005. Reproduced with the permission of Her Majesty's Stationery Office. Published by John Wiley & Sons, Ltd.
Regime shift in the global sea‐surface temperatures: its relation to El Niño–southern oscillation events and dominant variation modes
Authors: Yasunaka Sayaka , Hanawa Kimio 
Published: June 2005

AbstractSignificant changes of mean state appearing widely in the global sea‐surface temperature (SST) anomaly field have happened five times from the 1910s to the 1990s: 1925, 1942, 1957, 1970 and 1976. Since the regions of change spread over both hemispheres and/or multiple oceanic basins, they can be considered as ‘global regime shifts’. The years of regime shifts are consistent with those of the Northern Hemisphere regime shifts reported by previous studies.It is also shown that the regime shifts have happened concurrently with El Niño–southern oscillation (ENSO) events, which seems to suggest that the ENSO event acts as a trigger of the regime shift. At the regime shift, the tropical Pacific SSTs change from La Niña (El Niño) to El Niño (La Niña) conditions within 1 year. Further, the ENSO events occur just after the regime shifts begin in the July to September (JAS) season and reach the mature phase in the January to March (JFM) season as a typical evolution of the ENSO events. After that, they continue to at least the next year.The five regime shifts detected have similar features in their seasonal evolution and persistence of signals. First, the shifts start in the JAS season: an SST change occurs in the eastern and central tropical Pacific, and a change in the mid‐latitudes of the North and South Pacific appears with the opposite sign. Then the shifts in the JFM season. The spatial patterns are similar to those of the JAS season, but signals in the North Pacific become remarkable. These features resemble those corresponding to a series of evolutions of ENSO events, but the signals in the North Pacific and the North Atlantic are much stronger than those of the typical ENSO events. After the shifts have happened, the changes in spatial patterns of SST that occurred at the regime shift persist until the next shift. The persistence of signals is more prominent in the JFM season than in the JAS season.From a review of the dominant variation modes in global SSTs using empirical orthogonal function (EOF) analyses, four modes are identified: the ENSO mode, the Southern Hemisphere trend mode, the North Pacific (NP) mode, and the Arctic oscillation (AO) mode. In the years when regime shifts occur, the ENSO mode, the NP mode, and the AO mode show significant concurrent phase reversals on the global scale as previously shown in the Northern Hemisphere. These findings provide a possible reason why SST changes in the regime shift are similar but not exactly the same pattern as that of ENSO. Furthermore, it can be considered that a simultaneous phase reversal of the NP mode would suppress the growth of anticyclonic (or cyclonic) circulation in the atmosphere over the western tropical Pacific. This suggests that an ENSO event, which begins with a regime shift, would not reverse its condition and last for the following several seasons. Copyright © 2005 Royal Meteorological Society
Objective analyses of annual, seasonal, and monthly temperature and salinity for the World Ocean on a 0.25° grid
Authors: Boyer Timothy , Levitus Sydney , Garcia Hernan , Locarnini Ricardo A. , Stephens Cathy , Antonov John 
Published: June 2005

AbstractObjectively analysed climatological mean fields of temperature and salinity have been calculated on a 0.25° grid for the World Ocean for the annual, seasonal, and monthly compositing periods using data from the World Ocean Database 2001. The annual and seasonal fields are calculated at standard levels from the surface to 5500 m. The monthly fields are calculated at standard levels from the surface to 1500 m. In comparison with similarly computed climatologies calculated on a 1° grid, ocean circulation features, such as the Gulf of Mexico Loop Current, are more clearly represented. The new 0.25° climatologies preserve most of the spatial resolution of earlier 0.25° temperature and salinity climatologies, while reducing noise by additional smoothing in horizontal space (geographically at each depth), vertically (along depth at each grid), as well as in time (Fourier filtering). Copyright © 2005 Royal Meteorological Society
Climatology, variability and extrema of ocean waves: the Web‐based KNMI/ERA‐40 wave atlas
Authors: Sterl Andreas , Caires Sofia 
Published: June 2005

AbstractThe European Centre for Medium‐Range Weather Forecasts (ECMWF) has recently finished ERA‐40, a reanalysis covering the period September 1957 to August 2002. One of the products of ERA‐40 consists of six‐hourly global fields of wave parameters, like significant wave height and wave period. These data have been generated with the centre's WAM wave model. From these results we have derived climatologies of important wave parameters, including significant wave height, mean wave period, and extreme significant wave heights. Particular emphasis is on the variability of these parameters, both in space and time. Besides being important for scientists studying climate change, these results are also important for engineers who have to design maritime constructions. This paper describes the ERA‐40 data and gives an overview of the results derived. The results are available on a global 1.5° × 1.5° grid. They are accessible from the Web‐based KNMI/ERA‐40 wave atlas at http://www.knmi.nl/waveatlas. Copyright © 2005 Royal Meteorological Society
An overview of the airflow distortion at anemometer sites on ships
Authors: Moat Bengamin I. , Yelland Margaret J. , Pascal Robin W. , Molland Anthony F. 
Published: June 2005

AbstractWind speed measurements obtained from ship‐mounted anemometers are biased by the presence of the ship itself distorting the flow of air to the anemometer. Recent studies have used numerical models to simulate the flow around very detailed representations of individual research ships in order to quantify the effects of flow distortion at the anemometer locations. Such anemometers are generally in well‐exposed positions, typically on a mast in the bows of the ship. In contrast, very little is known about the possible effects of airflow distortion on the wind speed measurements from fixed anemometers on Voluntary Observing Ships (VOS). This is because (1) the several thousand or so merchant vessels vary significantly in shape and size and it would be impractical to study each individual ship, and (2) the anemometer location is not usually known.This paper describes initial results from a study of flow distortion over ‘typical’ tankers and bulk carriers. A method to describe the shapes of these VOS and container ships is presented. The influence of distortion on the flow above the bridges of VOS is shown to be significant, with possible biases in the measured wind speed of between +11% and −100%, depending on the anemometer location. Recommendations for the siting of anemometers are made. Copyright © 2005 Royal Meteorological Society
The effect of instrument exposure on marine air temperatures: an assessment using VOSClim Data
Authors: Berry David I. , Kent Elizabeth C. 
Published: June 2005

AbstractObservations of marine air temperature (MAT) by Voluntary Observing Ships (VOS) are known to contain significant biases due to solar heating of the sensor environment. MAT and humidity observations are usually made using wet‐ and dry‐bulb thermometers housed in Stevenson screens, or with psychrometers. These instruments are typically mounted in the bridge wings or on the wheel‐house top. If not sited carefully then the instruments can be poorly exposed to the undisturbed environmental conditions and have inadequate ventilation, leading to biased observations of both MAT and humidity.In this paper we use observations collected as part of the VOS Climate (VOSClim) project to investigate the relationship between instrument exposure and heating errors. The heating errors are estimated as the difference between the observed MAT and the collocated output of a numerical weather prediction model. The instrument exposures are assessed from photographs of the instruments. Currently, photographs of the instruments and sufficient observations exist for 17 VOSClim ships.Two methods of assessing the instrument exposure using the observations are presented. The first method is based on the skewness of the distribution of estimated heating errors for individual ships. The second method is based on a correction developed to correct the heating errors and uses the ratio of the heating to cooling terms in the correction. When ships are ranked both on the skewness and on the ratio of the heating to cooling terms, there is a statistically significant correspondence between the rankings and the visual assessments of instrument exposure. The skewness of the distribution of estimated errors in MAT is proposed as a simple indicator of instrument exposure. Copyright © 2005 Royal Meteorological Society
Abrupt climatic changes and an unstable transition into a late Holocene Thermal Decline: a multiproxy lacustrine record from southern Sweden
Authors: Jessen Catherine A. , Rundgren Mats , Björck Svante , Hammarlund Dan 
Published: June 2005

AbstractThe transition from a middle Holocene relatively warm and stable climate to a cooler and unstable late Holocene climate is reconstructed using sediments from Lake Igelsjön, south‐ central Sweden. This multiproxy study illustrates local, regional and global scale responses to climatic change by focusing on a previously identified abrupt hydrological shift to cooler and/or wetter conditions around 4000 cal. yr BP. The results suggest that between ca. 4600 and ca. 3400 cal. yr BP, the environment around and within the lake responded in two major, well‐defined steps: the first between 4450 and 4350 cal. yr BP and the second between 4000 and 3800 cal. yr BP. A series of rapid fluctuations of short duration were superimposed on the general cooling trend, with the most severe aquatic response peaking at ca. 3800 cal. yr BP. Pollen percentage and influx values show forest composition and pollen productivity changes and a distinct decline in total and Corylus pollen influx in the period of 4000–3500 cal. yr BP. Stomatal‐based reconstruction of atmospheric CO2 concentration produced a tenuous decrease with a minimum between 3650 and 3500 cal. yr BP. Copyright © 2005 John Wiley & Sons, Ltd.
Late Quaternary history of the coastal Wahiba Sands, Sultanate of Oman
Authors: Preusser Frank , Radies Dirk , Driehorst Frauke , Matter Albert 
Published: June 2005

AbstractContinental sediments and geomorphological features of the coastal Wahiba Sands, Sultanate of Oman, reflect environmental variability in southeastern Arabia during the late Quaternary. Weakly cemented dune sands, interdune deposits and coastal sediments were dated by luminescence methods to establish an absolute chronology of changes in sedimentary dynamics. The dating results confirm previous assumptions that during times of low global sea level sand was transported by southerly winds from the exposed shelf onto the Arabian Peninsula. Two prominent phases of sand accumulation in the coastal area took place just before and after the last glacial maximum (LGM). A final significant period of dune consolidation is recognised during the early Holocene. However, no major consolidation of dunes appears to have occurred during the LGM and the Younger Dryas. In the northern part of the Wahiba Sands, these two periods are characterised by substantial sand deposition. This discrepancy is explained by the lack of conservation potential for dunes in the coastal area, probably caused by a low groundwater table due to low sea level and decreased precipitation. While the times of aeolian activity reflect arid to hyper‐arid conditions, lacustrine and pedogenically altered interdune deposits indicate wetter conditions than today caused by increased monsoonal circulation during the Holocene climatic optimum. Copyright © 2005 John Wiley & Sons, Ltd.