bluuebunny/crossref_metadata_2025_split huggingface dataset:
Air bubbles in accreted ice
Authors: Carras J. N. , Macklin W. C. 
Published: February 2007

AbstractOn the assumption that the concentration of air bubbles formed in freezing water is a function of the freezing rate, an expression for the concentration of air bubbles in accreted ice has been deduced. This expression has been confirmed by measurements of the bubble concentrations and size distributions in frozen bulk water and in ice accreted on rotating cylinders. Consequently, in both the wet and dry growth regimes it is the rate of freezing which essentially determines the bubble concentration. The size distribution of bubbles is determined by the amount of air available for bubble growth. This depends on the rate at which air diffuses out of the individual droplets during the freezing process. In the wet growth regime the freezing rate depends on the rate at which heat is dissipated from the accreting object by forced convection and also, depending on the fraction of unfrozen water, on the way in which the spongy deposits are finally frozen. In the dry growth regime the freezing rate of the accreted droplets depends on their size and speed of impact, since these determine the extent to which the droplets spread, and on the temperature of the deposit.The air bubble concentrations and size distributions were determined using ordinary optical microscopy so that only bubbles of radius greater than 1μm were counted and sized. In the dry growth regime the visible bubble concentrations range from about 106 to 108cm−3, depending primarily on the deposit temperature. The mean radii of the bubbles in the deposits range from 1 to 4μm. In the wet growth regime the bubble concentrations generally lie between 105 and 106cm−3 while the mean radii of the bubbles range from 10 to 50μm. Consequently, the two growth regimes may be readily distinguished.
Laboratory Experimental check of radiative air cooling theory
Authors: Corradini C. , Severini M. 
Published: February 2007

AbstractExperimental evidence of air mass cooling in the laboratory by infrared radiative exchanges is given.The experiments were carried out in a 50m3 chamber, with relative humidities less than 70%, in the absence of turbulent motions and haze. The measured values of the air temperature as a function of the height and time with decreasing floor temperature are compared with calculated values for which the radiative contribution is determined by the emissivity method.The difference, less than 10%, between experimental and theoretical coolings, gives evidence that the method of computing radiation flux divergence is sufficiently accurate for many meteorological purposes.
Baroclinic instability of a simple flow on the sphere
Authors: Hollingsworth A. 
Published: February 2007

AbstractWe examine the baroclinic instability problem in some simple two‐level models on a sphere. We find that there are large momentum transports associated with the growing waves. These transports are induced by aspects of the spherical geometry other than those included in the beta‐plane analysis. On the other hand, the beta‐plane gives a good description of the essential dynamics of the waves.
Periodic variations in stratospheric meridional wind from 20 to 65km: 80°N to 70°S
Authors: Nastrom G. D. , Belmont A. D. , Dartt D. G. 
Published: February 2007

AbstractHeight‐latitude sections for January along 70°E and 90°W in the northern hemisphere show a divergence zone above 50km near 60°N 70°E, and an intense, persistent (October–April) convergence zone above 40km near 50°N 90°W. Tidal meridional winds dominate circulation features in summer at all latitudes, and throughout the year at low latitudes. As most rocket data are taken in late morning and as there is an appreciable diurnal tide at rocket levels, all results given here apply only to late morning.Long‐term periodic features in the meridional wind are analysed. No appreciable periodic waves are found in the tropics. The quasi‐biennial oscillation, annual wave, and four‐month wave have maximum amplitudes of about 10, 20, and 10m/s respectively in the arctic near 45km. The phase of the annual wave changes by nearly 180° in a narrow zone near 45°N. The semiannual wave has an amplitude of 10m/s near 50°N above 50km with equinoctial phase dates in the region of maximum amplitude. The location of this polar semiannual wave corresponds closely to that previously found in the zonal wind.
On the eddy structure of hurricanes
Authors: Robock Alan 
Published: February 2007

AbstractGiven the general conditions present in a mature hurricane, this paper seeks to show by observational and theoretical means that the circulation regime within a hurricane, beyond a certain radius, must be of the eddy type rather than axisymmetric. This is done by first pointing out, following recent results of Starr, that mean radial circulations cannot transport angular momentum across surfaces of constant mean values of this quantity. A diagram is constructed showing such momentum surfaces obtained from data for a mean hurricane, and it is demonstrated that there must be a flux of momentum across these closed surfaces. This flux, therefore, can only be produced by an eddy type circulation regime.
A split semi‐implict reformulation of the Bushby‐Timpson 10‐level model
Authors: Burridge D. M. 
Published: February 2007

AbstractA split semi‐implicit reformulation of the Bushby‐Timpson 10–level model is described. The integration cycle is split into two main parts. Firstly, the dependent variables are advected by the wind using the explicit two‐step Lax‐Wendroff integration scheme with the grid staggered in time and space. Secondly, these advected values are adjusted to account for the terms that govern the motion of small amplitude inertio‐gravity waves in the model, using a combination of an unconditionally stable implicit scheme and a conditionally stable explicit scheme. A novel feature of the scheme is the implicit treatment of only two of the model's ten gravity wave modes. This split semi‐implicit scheme is more than four times as efficient as the original explicit scheme designed by Bushby and Timpson. The results of one semi‐implicit integration to 36 hours are described and compared with an integration made with Bushby and Timpson's original explicit scheme.
A numerical model of cumulonimbus convection generating a protected core
Authors: Berson F. A. , Baird G. 
Published: February 2007

AbstractThe theory of buoyant motion in a turbulent environment due to Priestley (1953) is applied to steady‐state Cb updraught. An axisymmetric numerical model of columnar convection is modified to allow for radial cloud structure and internal turbulence. In this model the net vertical body force on a fluid element is the buoyancy relative to adjacent elements, and represents a residual of environment‐referred buoyancy and non‐hydrostatic pressure gradient.Moisture exchange and lateral transfer of momentum and heat by mass exchange with the environment on the scale of the cloud are disregarded, yet the model gives realistic updraught velocities and cloud depth. It simulates such features as a dome rising from a protected core of the cloud, oscillating motion of cloud tops and penetration of the tropopause. In some respects the predicted behaviour compares favourably with actual measurements.An incidental result concerns the generating gross buoyancy which is determined by the ambient and pseudo‐adiabatic temperature lapse rates. It appears that the values of the latter rate published in Smithonian Meteorological Tables and incorporated in pseudo‐adiabats on aerological diagrams, are in error.
On the components of time series; the removal of spatial dependence
Authors: Dyer T. G. J. 
Published: February 2007

AbstractA linear model is fitted to the precipitation series of each group of stations formed by principal component analysis on 157 precipitation records (Dyer 1975). Precipitation can thus be decomposed into independent components one each for regional temporal effect, regional spatial effect, and a residual or micro‐effect. Each region has a temporal effect which is analysed for trend, enabling the conclusion to be made that Southern Africa's precipitation budget is stationary. On the other hand, trend on a microscale is present over randomly distributed parts of the country. Spectral analysis shows the oscillatory behaviour of the regional temporal effects, and provides information useful to the fitting of stochastic forecasting models to the data. The technique solves the problem of dependence between meteorological time series, and can be applied to any variable.
Statistics of vertical motion over land and water
Authors: Merry M. , Panofsky H. A. 
Published: February 2007

AbstractObservations from many sources have been brought together to study the relationship between the ratio of standard deviation of vertical velocity to friction velocity, and z/L where z is the height and L the Monin‐Obukhov length. A good compromise for this relationship is:

where ϕM is the normalized wind shear.This equation has been combined with theoretical expressions for the wind profile to derive a nomogram for the standard deviation of vertical angle as function of z/L and z/z0, where z0 is the roughness length.
Some observations and analysis of wind over non‐uniform terrain
Authors: Peterson Ernest W. , Kristensen Leif , Su Chang‐Chun 
Published: February 2007

AbstractContinuous measurements of wind were made throughout a layer extending from the surface to a depth of 12m over a distance along the direction of the wind of about 150 metres. It has been found that the variation in the elevation of the underlying terrain has a profound effect, larger than that of the variation in surface roughness. The shape of the downwind profiles is consistent with the prediction of second‐order‐closure change‐of‐roughness models. Another observational site has been selected for comparison and the study of flow over non‐uniform terrain is continuing.
Boundary layer flow over gentle curvilinear topography with a sudden change in surface roughness
Authors: Lo A. K. , McBean G. A. 
Published: February 2007

AbstractA new approach using a curvilinear coordinate system that enables incorporation of a change of roughness with a zero‐plane displacement or elevation change in a boundary‐layer model is presented. the effect of topography together with the rapid development of an internal boundary layer produce vertical wind speeds that reach a maximum value of about 25 % of the horizontal component. It is found that perturbations due to a smooth‐to‐rough transition together with an increase of elevation are stronger than those generated from a rough‐to‐smooth transition with a decrease of elevation.
Depth of edge influence of the agricultural‐forest landscape boundary, Southwestern China
Authors: Li Liguang , He Xingyuan , Li Xiuzhen , Wen Qingchun , He Hong S. 
Published: February 2007

AbstractThe landscape boundary is an important component of a landscape and often plays an indispensable role in regulating ecological flows. The primary objective of this study was to estimate how far the edge effects on agricultural‐forest landscape boundaries can penetrate into the forest and agricultural field. This will serve as a basis for understanding the interaction between forest and agricultural fields in the mountainous area of southwestern China and provide scientific basis for the practice of the policy of “returning agricultural field to forest.” Based on field investigations, three types of boundaries with six sampling transects were selected. We investigated the soil moisture, soil nutrients and vegetation diversity along the transect gradient and explored the depth of edge influence (DEI) with moving split‐window techniques for analyzing the data. DEI for soil moisture changed with the seasons, ranging from 6 m in the pepper field to 2 m in the forest during the dry season, and from 12 m in the pepper field to 2 m in the forest after heavy rain. DEI based on soil organic matter ranged from 1.5 to 10 m in the forest field, while it was not detected based on other soil nutrient factors. DEI based on vegetation diversity varied from 4 to 26 m and from 10 to 31 m in the forest and agricultural fields, respectively. These results provide the scientific basis for the policy “returning agricultural field to forest”. Based on these field observations, reducing human disturbance and revegetating with natural shrubs and meadows could be more effective for vegetation conservation in terms of soil moisture and soil nutrient content in the arid valley of the Minjiang River.
Fertilizability and chromosomal integrity of frozen-thawed Bryde's whale (Balaenoptera edeni) spermatozoa intracytoplasmically injected into mouse oocytes
Authors: Watanabe H. , Tateno H. , Kusakabe H. , Matsuoka T. , Kamiguchi Y. , Fujise Y. , Ishikawa H. , Ohsumi S. , Fukui Y. 
Published: February 2007

SUMMARYPrior to attempting thein vitroproduction of embryos in the Bryde's whale (Balaenoputera edeni), we investigated whether spermatozoa can retain the capacity for oocyte activation and pronucleus formation as well as chromosomal integrity under cryopreservation by using intracytoplasmic sperm injection (ICSI) into mouse oocytes. Regardless of motility and viability, whale spermatozoa efficiently led to the activation of mouse oocytes (90.3–97.4%), and sperm nuclei successfully transformed into male pronucleus within activated ooplasm (87.2–93.6%). Chromosome analysis at the first cleavage metaphase (M) of the hybrid zygotes revealed that a majority (95.2%) of motile spermatozoa had the normal chromosome complement, while the percentage of chromosomal normality was significantly reduced to 63.5% in immotile spermatozoa and 50.0% in dead spermatozoa due to the increase in structural chromosome aberrations. This is the first report showing that motile Bryde's whale spermatozoa are competent to support embryonic development.
Ovine (Ovis aries) blastula from an in vitro production system and isolation of primary embryonic stem cells
Authors: Zhu S-X. , Sun Z. , Zhang J-P. 
Published: February 2007

SUMMARYLivestock embryo production in in vitro systems has been highlighted due to the emergence of interest in embryo stem cells (ESC). ESC potency and their wide potential applications have been recognized in medicine, fundamental research fields and commercial markets due to ESC totipotency or pluripotency and self-renewal. Ovine ESC probably is a useful technical platform for transgenic livestock and animal cloning, but ESC lines have not yet been founded because of difficulties in ESC isolation and the lack of blastula materials. We have established an IVP (in vitro production) system in our laboratory, including in vitro maturation, in vitro fertilization and in vitro culture, to produce sheep blastula using fresh ovaries and testes collected from livestock production. This system can achieve rates of mature eggs and blastulas of 65 and 50% respectively, and can provide enough blastulas for ICM (inner cell mass) isolation. Furthermore, ESC-like clones were isolated from the ICM on ovine embryonic fibroblast (OEF) feeder cells and in ES-DMEM supplemented with the cell factors LIF and SCF, and these survived to the third passage, which was primarily identified by AKP staining and morphology. This work provides a basis for ovine ESC isolation and foundation of ESC lines.
A finite-state morphological grammar of Hebrew
Authors: YONA S. , WINTNER S. 
Published: February 2007

AbstractMorphological analysis is a crucial component of several natural language processing tasks, especially for languages with a highly productive morphology, where stipulating a full lexicon of surface forms is not feasible. This paper describes HAMSAH (HAifa Morphological System for Analyzing Hebrew), a morphological processor for Modern Hebrew, based on finite-state linguistically motivated rules and a broad coverage lexicon. The set of rules comprehensively covers the morphological, morpho-phonological and orthographic phenomena that are observable in contemporary Hebrew texts. Reliance on finite-state technology facilitates the construction of a highly efficient, completely bidirectional system for analysis and generation.
Investigation of the immunosuppressive activity of artemether on T‐cell activation and proliferation
Authors: Wang J‐X , Tang W , Shi L‐P , Wan J , Zhou R , Ni J , Fu Y‐F , Yang Y‐F , Li Y , Zuo J‐P 
Published: February 2007

Background and purpose:Artemisinin and its derivatives exhibit potent immunosuppressive activity. The purpose of the current study was to examine the immunosuppressive activity of artemether directly on T lymphocytes and to explore its potential mode of action.Experimental approach: In vitro, T‐cell proliferation was measured using [3H]‐thymidine incorporation assay in cells stimulated with ConA, alloantigen and anti‐CD3 antibody. CFSE‐labeled cell division and cell cycle distribution were monitored by flow cytometry. In vivo, the effects of artemether were evaluated in delayed‐type hypersensitivity (DTH) and purified T‐cell responses to ovalbumin in ovalbumin‐immunized mice. The activation of extracellular signal‐regulated kinase1/2 (ERK1/2) and Raf1 were assessed by Western blot analysis and the activation of Ras was tested in pull‐down assays.Key results:We show that, in vitro, artemether suppressed ConA‐ or alloantigen‐induced splenocyte proliferation, influenced production of the cytokines IL‐2 and IFN‐γ and inhibited cell cycle progression through the G0/G1 transition. In vivo, administration of artemether attenuated CD4 T‐cell‐mediated DTH reaction, and suppressed antigen‐specific T‐cell response in immunized mice. Further experiments showed that, treatment with artemether impaired both antigen‐ and anti‐CD3‐induced phosphorylation of ERK. In primary T cells, artemether profoundly inhibited anti‐CD3‐induced phosphorylation of Raf1 and activation of Ras.Conclusions and implications:This study provided experimental evidence of the immunosuppressive effects of artemether directly on T cells both in vitro and in vivo. Its immunosuppressive mechanism involved inhibition of the activation of the Ras‐Raf1‐ERK1/2 protein kinase cascade in T cells.British Journal of Pharmacology (2007) 150, 652–661. doi:10.1038/sj.bjp.0707137
Local expression of IGF‐1 accelerates muscle regeneration by rapidly modulating inflammatory cytokines and chemokines
Authors: Pelosi Laura , Giacinti Cristina , Nardis Chiara , Borsellino Giovanna , Rizzuto Emanuele , Nicoletti Carmine , Wannenes Francesca , Battistini Luca , Rosenthal Nadia , Molinaro Mario , Musar Antoniò 
Published: February 2007

ABSTRACTMuscle regeneration following injury is characterized by myonecrosis accompanied by local inflammation, activation of satellite cells, and repair of injured fibers. The resolution of the inflammatory response is necessary to proceed toward muscle repair, since persistence of inflammation often renders the damaged muscle incapable of sustaining efficient muscle regeneration. Here, we show that local expression of a muscle‐restricted insulin‐like growth factor (IGF)‐1 (mIGF‐1) transgene accelerates the regenerative process of injured skeletal muscle, modulating the inflammatory response, and limiting fibrosis. At the molecular level, mIGF‐1 expression significantly down‐regulated proinflammatory cytokines, such as tumor necrosis factor (TNF)‐alpha and interleukin (IL)‐1beta, and modulated the expression of CC chemokines involved in the recruitment of monocytes/macrophages. Analysis of the underlying molecular mechanisms revealed that mIGF‐1 expression modulated key players of inflammatory response, such as macrophage migration inhibitory factor (MIF), high mobility group protein‐1 (HMGB1), and transcription NF‐KB. The rapid restoration of injured mIGF‐1 transgenic muscle was also associated with connective tissue remodeling and a rapid recovery of functional properties. By modulating the inflammatory response and reducing fibrosis, supplemental mIGF‐1 creates a qualitatively different environment for sustaining more efficient muscle regeneration and repair.—Pelosi, L., Giacinti, C., Nardis, C., Borsellino, G., Rizzuto, E., Nicoletti, C., Wannenes, F., Battistini, L., Rosenthal, N., Molinaro, M., Musaro, A. Local expression of IGF‐1 accelerates muscle regeneration by rapidly modulating inflammatory cytokines and chemokines. FASEB J. 21, 1393–1402 (2007)
Tumor‐specific antivascular effect of TZT‐1027 (Soblidotin) elucidated by magnetic resonance imaging and confocal laser scanning microscopy
Authors: Natsume Tsugitaka , Watanabe Junichi , Ogawa Kenji , Yasumura Kazuhiko , Kobayashi Motohiro 
Published: February 2007

TZT‐1027 (soblidotin), an antimicrotubule agent, has previously been evaluated in terms of its antivascular effects. In this study, Evans blue perfusion, magnetic resonance imaging (MRI), and confocal laser scanning microscopy (CLSM) were utilized to further elucidate the antivascular effect of TZT‐1027 in female nude mice and rats bearing human breast tumor MX‐1, as well as in female Sprague‐Dawley rats that developed breast tumors induced by dimethylbenz(a)anthracene (DMBA). Therapeutic doses of TZT‐1027 caused nearly complete regression of implanted MX‐1 tumors in nude mice and rats as well as DMBA‐induced tumors in rats. The perfusion in MX‐1 tumor implanted in nude mice was drastically reduced within 30 min after TZT‐1027 administration and was completely inhibited after 6 h or more, although not reduced in normal tissue of kidney. The study using MRI demonstrated that rich blood flow within tumors was remarkably reduced 1–3 h after TZT‐1027 administration both in nude rats bearing MX‐1 tumors and in rats with DMBA‐induced tumors. Furthermore, the study with CLSM in nude mice bearing MX‐1 tumors revealed a disruption of tumor microvessels at 1 h and a destruction of tumor microvessel network at 3 h after TZT‐1027 administration. In contrast, these types of vascular disorders were not observed in heart and kidney. These results suggest that TZT‐1027 specifically damages tumor vasculatures, leading to extensive tumor necrosis within tolerable dose range, and confirms earlier observations that TZT‐1027 exerts a considerable antivascular effect in addition to an excellent cytotoxic effect. (Cancer Sci 2007; 98: 598–604)
Do threatened hosts have fewer parasites? A comparative study in primates
Authors: ALTIZER SONIA , NUNN CHARLES L. , LINDENFORS PATRIK 
Published: February 2007

SummaryParasites and infectious diseases have become a major concern in conservation biology, in part because they can trigger or accelerate species or population declines. Focusing on primates as a well‐studied host clade, we tested whether the species richness and prevalence of parasites differed between threatened and non‐threatened host species.We collated data on 386 species of parasites (including viruses, bacteria, protozoa, helminths and arthropods) reported to infect wild populations of 36 threatened and 81 non‐threatened primate species. Analyses controlled for uneven sampling effort and host phylogeny.Results showed that total parasite species richness was lower among threatened primates, supporting the prediction that small, isolated host populations harbour fewer parasite species. This trend was consistent across three major parasite groups found in primates (helminths, protozoa and viruses). Counter to our predictions, patterns of parasite species richness were independent of parasite transmission mode and the degree of host specificity.We also examined the prevalence of selected parasite genera among primate sister‐taxa that differed in their ranked threat categories, but found no significant differences in prevalence between threatened and non‐threatened hosts.This study is the first to demonstrate differences in parasite richness relative to host threat status. Results indicate that human activities and host characteristics that increase the extinction risk of wild animal species may lead simultaneously to the loss of parasites. Lower average parasite richness in threatened host taxa also points to the need for a better understanding of the cascading effects of host biodiversity loss for affiliated parasite species.