bluuebunny/crossref_metadata_2025 huggingface dataset:
Catatonia in Alzheimer's disease: The role of the amygdalo-hippocampal circuits
Authors: Miu Andrei C. , Olteanu Adrian I.
Published: September 2003

The intrinsic merit of Northoff's model lies primarily in the fact that it integrates data concerned with different levels of organization of the brain. This approach implicitly argues against reductionism, although, apparently, its rather simplistic assumption gives too many degrees of freedom. In considering that a symptom from two different syndromes indicates a common neural alteration, we grossly disregard neural plasticity.
Double dissociations never license simple inferences about underlying brain organization, especially in developmental cases
Authors: McClelland James L. , Lupyan Gary
Published: September 2003

Different developmental anomalies produce contrasting deficits in a single, integrated system. In a network that inflects regular and exception verbs correctly, a disproportionate deficit with exceptions occurs if connections are deleted, whereas a disproportionate deficit with regulars occurs when an auditory deficit impairs perception of the regular inflection. In general, contrasting deficits do not license the inference of underlying modularity.
The best is yet to come: The promise of models of developmental disorders
Authors: Munakata Yuko , Edgin Jamie O. , Stedron Jennifer Merva
Published: September 2003

The developmental modeling approach to investigating developmental disorders appears highly promising. In this commentary, we question the untapped potential of this approach for supporting insights into particular developmental disorders, developmental processes across the life span, and the viability of traditional theories of developmental disorders.
Does the new paradigm in ape-language research ape behaviorism?
Authors: Pear Joseph J.
Published: September 2003

Although Shanker & King (S&K) disregard the behavioral paradigm, their arguments are reminiscent of those in Skinner's Verbal Behavior (1957). Like S&K, Skinner maintained that communication is not appropriately characterized as the transmission of information between individuals. In contrast to the paradigm advocated by S&K, however, the behavioral paradigm emphasizes prediction and control as important scientific goals.
CONTRASTIVE RHETORIC REVISITED AND REDEFINED. Clayann Gilliam Panetta (Ed.). Mahwah, NJ: Erlbaum, 2001. Pp. xx + 134. $39.95 cloth, $17.95 paper.
Authors: Biber Douglas
Published: September 2003

Contrastive rhetoric—an analytical framework for the study of second language writing—has had incredible staying power. Since Kaplan's (1966) original paper, this framework has been used in dozens of studies that compare the rhetorical organizations of written texts produced by writers from different cultures and native languages (L1s). Additionally, the framework has been elaborated and refined considerably to account for the extensive range of linguistic variability found among written texts from different text types; more recent treatments include Grabe and Kaplan (1996, chap. 7) and Connor (1996).
Isolated gingival metastasis from hepatocellular carcinoma mimicking a pyogenic granuloma
Authors: Ramirez José Ramón , Seoane Juan , Montero Juan , Esparza Gómez Germán C. , Cerero Rocio
Published: September 2003

Background: Oral metastatic tumours are uncommon and account for approximately 1% of malignant oral neoplasms.

Results: If the cases where the oral location is in the jawbone, with secondary invasion to the oral soft tissue, are excluded, only 10 cases of gingival metastasis from hepatocellular carcinoma (HCC) have been previously reported in the literature. The clinicopathologic features of an HCC with gingival metastasis are reported. Six months after the multicentric HCC and alcoholic cirrhosis was diagnosed, a 65‐year‐old male patient presented a rapidly growing, lobulated and reddish exophytic lesion that was located in the gum in the incisal region of the upper jaw. The lesion was excised, and the final diagnosis of gingival metastasis of the HCC was established. Diagnostic investigations did not show any evidence of other metastatic lesions. This article describes a case with solitary metastasis from HCC in the gingiva, an event that, to our knowledge, has not been previously published.

Conclusions: The clinical appearance of isolated gingival metastasis from HCC in the present case mimicked a pyogenic granuloma.
Salivary cystatin activity and cystatin C in experimental gingivitis in non‐smokers
Authors: Van Gils P. C. , Brand H. S. , Timmerman M. F. , Veerman E. C. I. , Van Der Velden U. , Van Der Weijden G. A.
Published: September 2003

Background: Subjects with natural gingivitis and periodontitis have elevated levels of salivary cystatins compared to periodontally healthy individuals. Experimental gingivitis studies, however, have yielded conflicting results.

Aim: The present study investigated whether experimentally induced gingivitis is associated with changes in salivary cystatin levels.

Material & Methods: Plaque scores, bleeding indexes and whole saliva samples of 35 non‐smoking young adults were collected at the start and at the end of an experimental gingivitis trial, and 3 weeks after resuming oral hygiene. The saliva samples were assayed for protein concentrations, cystatin activity and cystatin C concentration.

Results: During experimental gingivitis, plaque and bleeding scores increased significantly in all subjects and subsequently decreased significantly after reinstalment of oral hygiene procedures. No significant changes were observed for the protein concentration, cystatin activity and cystatin C concentration. No significant relation could be established between these salivary parameters and bleeding on marginal probing.

Conclusion: The present study confirms earlier results from Lie et al. (2001) that no significant changes occur in salivary cystatin activity and cystatin C concentration during and after experimental gingivitis.
Peroxisome division in the yeast Yarrowia lipolytica is regulated by a signal from inside the peroxisome
Authors: Guo Tong , Kit Yuriy Y. , Nicaud Jean-Marc , Le Dall Marie-Therese , Sears S. Kelly , Vali Hojatollah , Chan Honey , Rachubinski Richard A. , Titorenko Vladimir I.
Published: September 2003

We describe an unusual mechanism for organelle division. In the yeast Yarrowia lipolytica, only mature peroxisomes contain the complete set of matrix proteins. These mature peroxisomes assemble from several immature peroxisomal vesicles in a multistep pathway. The stepwise import of distinct subsets of matrix proteins into different immature intermediates along the pathway causes the redistribution of a peroxisomal protein, acyl-CoA oxidase (Aox), from the matrix to the membrane. A significant redistribution of Aox occurs only in mature peroxisomes. Inside mature peroxisomes, the membrane-bound pool of Aox interacts with Pex16p, a membrane-associated protein that negatively regulates the division of early intermediates in the pathway. This interaction inhibits the negative action of Pex16p, thereby allowing mature peroxisomes to divide.
Information as sign: semiotics and information science
Authors: Raber Douglas , Budd John M.
Published: September 2003

From the perspective of semiotics, “information” is an ambiguous theoretical concept because the word is used to represent both signifier and signified, both text and content. Using the work of Fernand de Saussure, this paper explores theoretical possibilities that open by virtue of understanding information as sign. Of particular interest is the way semiotics suggests ways to bridge the theoretical gap between information as thing and information as cognitive phenomenon by positing information as a cultural phenomenon.
Trust in countries in transition: empirical evidence from agriculture
Authors: Slangen Louis H.G. , Suchánek Pavel , Cornelis van Kooten G.
Published: September 2003

It is well‐known that institutions and social capital are important determinants of economic development, and that trust is an important component of social capital. In this paper, factor analysis and three regression models are employed to analyze determinants of trust in central and eastern European countries (CEECs). The results indicate that the rule of law, the protection of property rights, and lower levels of perceived government corruption have a positive effect on trust in agriculture.
Modeling of cavitating or ventilated flows using BEM
Authors: Kinnas Spyros A. , Young Yin L.
Published: September 2003

Boundary element method (BEM) techniques for the prediction of cavitating or ventilated flows around hydrofoils and propeller are summarized. Classical, supercavitating, and ventilated blade section geometries are considered. Recent extensions which allow for the modeling of cavities on either or both sides of the blade surface are presented. Numerical validation studies and comparisons with experimental measurements are shown.
Human Genome Sequence Variation and the Search for Genes Influencing Stroke
Authors: Rosand Jonathan , Altshuler David
Published: September 2003

Background—

Technological progress spurred by the Human Genome Project is accelerating the pace of genetic studies of common diseases, including stroke. Stroke clinicians will soon need to interpret increasingly complex genetic studies.

Summary of Review—

Linkage analysis and epidemiological association are 2 fundamental methods of identifying gene variants affecting common diseases such as stroke. Combining these methods with advanced molecular genetic techniques, 3 recently published studies have made important contributions to the genetics of common vascular diseases: identification of the location of a gene for stroke on chromosome 5q12 and identification of gene variants that may increase risk of myocardial infarction. Driven by genomic technology, future studies will be increasingly comprehensive and systematic in their assessment of the contribution of genetics to the clinical course of stroke. The scale and complexity of such studies will require large-scale collaboration among stroke physicians, geneticists, and biostatisticians.

Conclusions—

Rapid improvements in technology and study design are likely to elucidate the role of inherited genetic variation in complex diseases such as stroke. Understanding the methods of population-based genetic investigation and the patterns of human genome variation will enable stroke physicians to follow these future developments.
Significance of intraoperative peritoneal culture of fungus in perforated peptic ulcer
Authors: Shan Y-S , Hsu H-P , Hsieh Y-H , Sy E D , Lee J-C , Lin P-W
Published: September 2003

Background

The incidence of postoperative fungal infection is increasing and the gastrointestinal tract is the major source, but antifungal therapy in perforated peptic ulcer (PPU) is still controversial. The aim of this study was to determine the significance of intraoperative peritoneal fluid culture of fungus and establish the indications for treatment.

Methods

Between July 1997 and September 2001, all patients admitted with a PPU were studied. Clinical data and peritoneal fluid for culture were collected. Risk factors for a positive peritoneal fluid culture of fungus and outcome were evaluated, and related to the development of surgical site infection, duration of hospital stay and mortality rate.

Results

One hundred and forty-five patients with a PPU were included; 63 (43·4 per cent) had positive peritoneal fluid fungal culture. Age, preoperative organ failure, delay in operation, high Mannheim Peritonitis Index (MPI) and Acute Physiology And Chronic Health Evaluation (APACHE) II scores, and preoperative antibiotic therapy were risk factors for a positive fungal culture. Sex and an MPI score of 20 or more remained significant in multivariate analysis (P < 0·001). Patients with a positive fungal culture had a higher incidence of surgical site infection, a longer hospital stay and a significantly higher mortality rate, especially when this was combined with a high MPI score.

Conclusion

Positive peritoneal fungal culture was common and was a significant risk factor for adverse outcome in patients with a PPU. A high MPI score could be used as an indicator for prophylactic antifungal therapy.
Letter 1: Randomized clinical trial of ultrasonic versus electrocautery dissection of the gallbladder in laparoscopic cholecystectomy (Br J Surg 2003; 90: 799-803)
Authors: Morino M
Published: September 2003

The Editors welcome topical correspondence from readers relating to articles published in the Journal. Responses can be sent electronically via the BJS website (www.bjs.co.uk) or by post. All letters will be reviewed and, if approved, appear on the website. A selection of these will be edited and published in the Journal. Letters must be no more than 250 words in length. Letters submitted by post should be typed on A4-sized paper in double spacing and should be accompanied by a disk.
Anchors not inner codes, coordination not translation (and hold the modules please)
Authors: Clark Andy
Published: September 2003

Peter Carruthers correctly argues for a cognitive conception of the role of language. But such a story need not include the excess baggage of compositional inner codes, mental modules, mentalese, or translation into logical form (LF).
A linguistic module for integrating the senses, or a house of cards?
Authors: Dale Rick , Spivey Michael
Published: September 2003

Carruthers invokes a number of controversial assumptions to support his thesis. Most are questionable and unnecessary to investigate the wider relevance of language in cognition. A number of research programs (e.g., interactionist psycholinguistics and cognitive linguistics) have for years pursued a similar thesis and provide a more empirically grounded framework for investigating language’ cognitive functions.
You can dance if you want to
Authors: Kuhlmeier Valerie , Bloom Paul
Published: September 2003

We argue that the dance metaphor does not appropriately characterize language. Indeed, language may be a red herring, distracting us from the intriguing question of the nature of apes' social interactions.
The K-shell radiation of a double gas puff
z-pinch with an axial magnetic field
Authors: CHAIKOVSKY S.A. , LABETSKY A.Yu. , ORESHKIN V.I. , SHISHLOV A.V. , BAKSHT R.B. , FEDUNIN A.V. , ROUSSKIKH A.G.
Published: September 2003

A double shell z-pinch with an axial magnetic field
is considered as a K-shell plasma radiation source.
One-dimensional radiation-hydrodynamics calculations performed
suggest that this scheme holds promise for the production of
the K-shell radiation of krypton (hν ≈
12–17 keV). As a first step in verifying the advantages of
this scheme, experiments have been performed to optimize a neon
double-shell gas puff with an axial magnetic yield for the
K-shell yield and power. The experiments show that the
application of an axial magnetic field makes it possible to increase
the K-shell radiation power and reduce the shot-to-shot
spread in the K-shell yield. Comparisons between the
experiments and modeling are made and show good agreement.
Cancer and Peutz‐Jeghers Syndrome: A Review
Authors: Ivanovich Jennifer L. , Whelan Alison J.
Published: September 2003

Peutz‐Jeghers syndrome is a dominantly inherited polyposis syndrome characterized by hamartomatous polyps of the gastrointestinal tract and pigmented lesions of the skin. Since its description, much debate has centered on the true malignancy risk of Peutz‐Jeghers syndrome including malignancy within and outside the gastrointestinal tract. Rare tumors such as adenoma malignum of the cervix occur in Peutz‐Jeghers syndrome. Likewise, more common cancers occur at younger ages in Peutz‐Jeghers syndrome. Children may manifest symptoms of this disease including gastrointestinal complications and malignancy. The gene associated with this condition remains unidentified.
On magma chamber evolution during slow effusive eruptions
Authors: Woods Andrew W. , Huppert Herbert E.
Published: August 2003

We explore some of the controls on the evolution of a slow effusive eruption imposed by processes in a shallow magma reservoir. We envisage that the emplacement of basaltic magma into a shallow, evolved crustal reservoir generates sufficient overpressure to trigger the slow effusive eruption of the overlying layer of evolved magma. The subsequent evolution of the system then depends on a number of factors including (1) the volatile contents of the two magmas; (2) the rate of any continuing influx of basalt; (3) the cooling/heating rates of the two layers of magma; and (4) the eruption rate of the silicic magma, where we assume that the crystals and bubbles remain in the layer in which they formed. Any exsolved volatiles in the magma increase the compressibility of the magma. In a waning system, this tends to increase the volume of material, which needs to be erupted to relieve a given overpressure by an amount of order 10–100, and hence increases the duration of the eruption. Typical calculations suggest that eruptions from magma chambers of size 1–10 km3 may persist for times of order 1–10 years if the main body of silicic magma is saturated in volatiles. In addition, cooling of the basalt leads to formation of dense crystals, which lowers the pressure. However, if the magma becomes saturated, exsolution of volatile gases occurs, tending to increase the pressure. Again, in a waning system, this tends to extend the eruption duration and increase the mass erupted from the chamber. For chamber volumes of 1–10 km3, cooling rates of 10−6 K/s can increase the eruption volume by a factor of order 10. Rapid cooling may also lead to an initial increase in the eruption rate, while the chamber pressure is controlled by the rate of production of new bubbles. If there is an influx of basalt to the chamber which is maintained during the eruption, then the evolution of the eruption is primarily dependent on this input rate, although the cooling of the basalt may increase the eruption rate to values in excess of this input rate, especially at an early stage in the eruption. The complex and nonlinear evolution of the eruption rate predicted by our simple model illustrates the sensitivity of the eruption rate to the magma volatile content and magma cooling rates. Such understanding is key in developing quantitative models for hazard assessments of slow effusive eruptions.
Apparent polar wander paths and the close of late Archean crustal transpression, northern Ontario
Authors: Borradaile G. J. , Lemmetty T. J. , Werner T.
Published: August 2003

Lamprophyre dikes of the southern Superior Province of the Canadian Shield crosscut Archean structures, including a late Archean unconformity and its overlying younger Archean Timiskaming sedimentary and volcanic rocks. The dikes also cut the single schistosity that formed in these rocks. Nevertheless, the lamprophyre dikes show a weak internal tectonic fabric that is approximately parallel to the schistosity in the bedrock and oblique to dike walls. The consistent orientation of this internal tectonic fabric has been recognized in every lamprophyre dike using anisotropy of magnetic susceptibility (AMS). Thus the lamprophyre dikes provide a useful chronological marker, trapping the last pulse of Archean tectonism. Unfortunately, our previous attempts to compare the lamprophyre paleopoles with those of the age‐calibrated apparent polar wander path (APWP) failed because it was not possible to isolate separate young and old components of magnetization. That failure occurred due to the overlap of blocking temperatures or coercivities for the different characteristic vector components [Borradaile et al., 1994a]. Using new cores from the same specimens, here we distinguish successfully between consistently oriented vector components by using low‐temperature demagnetization (LTD) before thermal demagnetization. Although the paleopoles appear well defined, comparisons with published APWPs for the Superior Province from late Archean [Irving, 1979; Dunlop, 1983; Symons et al., 1994] to early Proterozoic [Buchan et al., 2000] are difficult. Moreover, the earlier parts of the paths are progressively less precise and complete. Nevertheless, A component remanences for the dikes give a paleopole near the path at ∼2650 Ma. For a Timiskaming volcanic breccia with a U‐Pb age of 2696 Ma the A component paleopole may lie between 2600 and 2650 Ma. B component remanences yield paleopoles in the NW Pacific region, incompatible with any proposed Archean path but perhaps representing some much younger Proterozoic remagnetization event (e.g., Keweenawan, ∼1100 Ma).
Dynamics of mean and subtidal flow on the New England shelf
Authors: Shearman R. Kipp , Lentz Steven J.
Published: August 2003

Current and hydrographic observations from the Coastal Mixing and Optics experiment moored array, deployed from August 1996 through June 1997, are used to describe the velocity variability and evaluate the dynamics of circulation over the New England shelf on timescales ranging from a few days to several months. Subtidal (days to weeks) current variability was polarized along‐isobath and dominated by episodic bursts of westward flow. The along‐isobath subtidal flow was primarily geostrophic and barotropic, and was correlated with large‐scale along‐coast wind stress fluctuations oriented 45°T (65° counterclockwise from the local isobath orientation). Subtidal near‐surface ageostrophic transport matched estimates of wind‐driven Ekman transport; however, near‐bottom ageostrophic transport was much larger than estimates of Ekman transport from bottom stress. Low‐frequency (monthly and longer timescales) flow was generally westward and off‐shelf at all sites and depths, with the strongest westward flow during the fall. Low‐frequency along‐isobath currents were primarily geostrophic with baroclinic and barotropic components of similar magnitude. Depth‐averaged ageostrophic transport was quantitatively consistent with Ekman transport from wind and bottom stress. Measured bottom stress at both subtidal and low‐frequency timescales was weak, nearly an order of magnitude smaller than the wind stress. Low‐frequency fluctuations in the predominantly geostrophic along‐isobath flow were attributable to variations in the cross‐shelf density field associated with the seasonal cycle in surface heating. During the fall, thermal wind shear was strongest, because the cross‐isobath temperature gradient was acting in concert with the persistent cross‐isobath salinity gradient to enhance the cross‐isobath density gradient (i.e., warmer and fresher water inshore). During the winter, in response to surface cooling, the cross‐isobath temperature gradient reversed sign, reducing the cross‐isobath density gradient (i.e., cooler and fresher water inshore).
A three‐dimensional numerical simulation of Typhoon Holly in the northwestern Pacific Ocean
Authors: Hong Chul‐Hoon , Yoon Jong‐Hwan
Published: August 2003

A three‐dimensional primitive equation model (the Princeton Ocean Model, often called POM) has been implemented for simulating Typhoon Holly generated in the tropical Pacific Ocean. This is the first time that a study of this type, previously used mostly for coastal, regional simulations, has been implemented for the northwestern Pacific Ocean, from 24°N to 52°N, including the East China Sea, the Yellow Sea, and the East (Japan) Sea. In the open ocean the model circulation, sea surface elevation, and temperature distribution with the passage of Holly are described; the results are in part compared with observation in the Korea (Tsushima) Strait. The model reproduces well several prominent features obtained in the observation such as a rapid increase of temperature in the Korea Strait during the passage of Typhoon Holly, in August 1984, and reasonably explains how they happened. Around the vicinity of the typhoon center, the model temperature field successfully presents “sea surface cooling” in the open ocean, having been frequently observed in the past. The model also suggests that a coastal jet around the Korea Strait and a cyclonic eddy field behind Holly in the East China Sea play an important role in the oceanic conditions although they have not yet been identified by observations.
High‐frequency response of wind‐driven currents measured by drifting buoys and altimetry over the world ocean
Authors: Rio M.‐H. , Hernandez F.
Published: August 2003

We investigate the wind‐driven current response over the world ocean using SVP drifting buoys, ERS‐1 and ERS‐2, and TOPEX altimetry data and ECMWF wind stress fields. Wind‐driven ageostrophic currents are estimated from drifting buoys by removing altimetry deduced geostrophic currents from observed drifting velocities. Removing the geostrophic signal enhances the coherence with wind stress at periods longer than 10 days. For superinertial periods lower than 20 days, a two‐parameter (i.e., angle and amplitude) model is fitted to the isolated ageostrophic signal to study the upper ocean response to surface wind stress in that frequency band. The model, which can explain up to 30% of the variance in some areas, indicates that the currents spiral to the right (left) of the wind with depth in the Northern (Southern) Hemisphere, in agreement with the Ekman theory. The absolute value of the angle parameter is found to exhibit significant spatial and seasonal variability. The vertical eddy viscosity and the Ekman layer depth as deduced from Ekman theory are compared to previous results. Their seasonal variability is also studied. Model results are then used to compute the mean and standard deviation of ageostrophic currents in 5° boxes over the world ocean. The equatorial divergence and the subpolar and subtropical convergence zones are well reproduced.
Symmetric and antisymmetric mass exchanges between the equatorial and off‐equatorial Pacific associated with ENSO
Authors: Kug Jong‐Seong , Kang In‐Sik , An Soon‐Il
Published: August 2003

Mass exchanges in the upper ocean between the equatorial and off‐equatorial Pacific Ocean associated with the El Niño/Southern Oscillation (ENSO) are investigated using the National Centers for Environmental Prediction (NCEP) ocean assimilation data. The data show that ENSO‐related meridional mass transport in the Northern Hemisphere (NH) is larger than that in the Southern Hemisphere (SH). We found that the antisymmetric characteristics are mainly due to a southward shift of the maximum zonal wind stress anomaly during the ENSO mature phase. The Ekman and geostrophic transports associated with ENSO are separated into symmetric and antisymmetric components. For the symmetric part, the mass divergence over the equatorial Pacific by the geostrophic transport is generally larger than the convergence by the Ekman transport during the El Niño mature phase. Therefore mass is transported from the equator to off the equator at this time. As for the antisymmetric part, the Ekman transport due to antisymmetric wind stress dominates the geostrophic transport so that the mass is transported from the SH to the NH during the El Niño mature phase. The net mass transport in the NH is larger than that in the SH. A theoretical interpretation and intermediate model experiments support these arguments.
Comprehensive characterization of PM2.5 aerosols in Singapore
Authors: Balasubramanian R. , Qian W.‐B. , Decesari S. , Facchini M. C. , Fuzzi S.
Published: August 2003

A comprehensive characterization of PM2.5 aerosols collected in Singapore from January through December 2000 is presented. The annual average mass concentration of PM2.5 was 27.2 μg/m3. The atmospheric loading of PM2.5 was elevated sporadically from March through May, mainly due to advection of biomass burning (deliberate fires to clear plantation areas) impacted air masses from Sumatra, Indonesia. Satellite images of the area, trajectory calculations, and surface wind direction data are in support of the transport of pyrogenic products from Sumatra toward Singapore. Aerosol samples collected during the dry season were analyzed for water‐soluble ions, water‐soluble organic compounds (WSOC), elemental carbon (EC), organic carbon, and trace elements using a number of analytical techniques. The major components were sulfate, EC, water‐soluble carbonaceous materials, and water‐insoluble carbonaceous materials. Aerosol WSOC were characterized based on a combination of chromatographic separations by ion exchange chromatography, functional group investigation by proton nuclear magnetic resonance, and total organic carbon determination. The comprehensive chemical characterization of PM2.5 particles revealed that both non‐sea‐salt sufate (nss‐SO42−) and carbonaceous aerosols mainly contributed to the increase in the mass concentration of aerosols during the smoke haze period. Using a mass closure test (a mass balance), we determined whether the physical measurement of gravimetric fine PM concentration of a sample is equal to the summed concentrations of the individually identified chemical constituents (measured or inferred) in the sample. The sum of the determined groups of aerosol components and the gravimetrically determined mass agreed reasonably well. Principal component analysis was performed from the combined data set, and five factors were observed: a soil dust component, a metallurgical industry factor, a factor representing emissions from biomass burning and automobiles, a sea‐salt component, and an oil combustion factor.
Sensitivity of the atmospheric lapse rate to solar cloud absorption in a radiative‐convective model
Authors: Erlick Carynelisa , Ramaswamy V.
Published: August 2003

Previous radiative‐convective model studies of the radiative forcing due to absorbing aerosols such as soot and dust have revealed a strong dependence on the vertical distribution of the absorbers. In this study, we extend this concept to absorption in cloud layers, using a one‐dimensional radiative‐convective model employing high, middle, and low cloud representations to investigate the response of the surface temperature and atmospheric lapse rate to increases in visible cloud absorption. The visible single‐scattering albedo (ssa) of the clouds is prescribed, ranging from 1.0 to 0.6, where 0.99 is the minimum that would be expected from the presence of absorbing aerosols within the cloud drops on the basis of recent Monterey Area Ship Track (MAST) Experiment case studies. Simulations are performed with respect to both a constant cloud optical depth and an increasing cloud optical depth and as a function of cloud height. We find that increases in solar cloud absorption tend to warm the troposphere and surface and stabilize the atmosphere, while increases in cloud optical depth cool the troposphere and surface and slightly stabilize the atmosphere between the low cloud top and surface because of the increase in surface cooling. In the absence of considerations involving microphysical or cloud‐climate feedbacks, we find that two conditions are required to yield an inversion from a solar cloud absorption perturbation: (1) The solar absorption perturbation must be included throughout the tropospheric clouds column, distributing the solar heating to higher altitudes, and (2) the ssa of the clouds must be ≤0.6, which is an unrealistically low value. The implication is that there is very little possibility of significant stabilization of the global mean atmosphere due to perturbation of cloud properties given current ssa values.
An intercomparison of lidar‐derived aerosol optical properties with airborne measurements near Tokyo during ACE‐Asia
Authors: Murayama Toshiyuki , Masonis Sarah J. , Redemann Jens , Anderson Theodore L. , Schmid Beat , Livingston John M. , Russell Philip B. , Huebert Barry , Howell Steven G. , McNaughton Cameron S. , Clarke Antony , Abo Makoto , Shimizu Atsushi , Sugimoto Nobuo , Yabuki Masanori , Kuze Hiroaki , Fukagawa Shunsuke , Maxwell‐Meier Kari , Weber Rodney J. , Orsini Douglas A. , Blomquist Byron , Bandy Alan , Thornton Donald
Published: August 2003

During the ACE‐Asia intensive observation period (IOP), an intercomparison experiment with ground‐based lidars and aircraft observations was conducted near Tokyo. On 23 April 2001, four Mie backscatter lidars were simultaneously operated in the Tokyo region, while the National Center for Atmospheric Research C‐130 aircraft flew a stepped‐ascent profile between the surface and 6 km over Sagami Bay southwest of Tokyo. The C‐130 observation package included a tracking Sun photometer and in situ packages measuring aerosol optical properties, aerosol size distribution, aerosol ionic composition, and SO2 concentration. The three polarization lidars suggested that the observed modest concentrations of Asian dust in the free troposphere extended up to an altitude of 8 km. We found a good agreement in the backscattering coefficient at 532 nm among lidars and in situ 180° backscatter nephelometer observations. The intercomparison indicated that the aerosol layer between 1.6 and 3.5 km was a remarkably stable and homogenous in mesoscale. We also found reasonable agreement between the aerosol extinction coefficients (σa ∼ 0.03 km−1) derived from the airborne tracking Sun photometer, in situ optical instruments, and those estimated from the lidars above the planetary boundary layer (PBL). We also found considerable vertical variation of the aerosol depolarization ratio (δa) and a negative correlation between δa and the backscattering coefficient (δa) below 3.5 km. Airborne measurements of size‐dependent optical parameters (e.g., the fine mode fraction of scattering) and of aerosol ionic compositions suggests that the mixing ratio of the accumulation‐mode and coarse‐mode (dust) aerosols was primarily responsible for the observed variation of δa. Aerosol observations during the intercomparison period captured the following three types of layers in the atmosphere: a PBL (surface to 1.2–1.5 km) where fine (mainly sulfate) particles with a low δa (<10%) dominated; an intermediate layer (between the top of the PBL and 3.5 km) where fine particles and dust particles were moderately externally mixed, giving moderate δa; and an upper layer (above ∼3.5 km) where dust dominated, giving a high δa (30%). A substantial dust layer between 4.5 and 6.5 km was observed just west of Japan by the airborne instruments and found to have a lidar ratio of 50.4 ± 9.4 sr. This agrees well with nighttime Raman lidar measurements made later on this same dust layer as it passed over Tokyo, which found a lidar ratio of 46.5 ± 10.5 sr.
The annual cycle of riverine influence in the eastern Gulf of Mexico basin
Authors: Morey Steven L. , Schroeder William W. , O'Brien James J. , Zavala‐Hidalgo Jorge
Published: August 2003

The annual cycle of the surface salinity field in the eastern Gulf of Mexico (GoM) basin is investigated with a numerical model and observational data. A tongue of low salinity water is evident in the model climatology spreading southward from the Mississippi ‐ Alabama ‐ Florida (MAFLA) shelf and De Soto Canyon in the summer. The model salinity climatology along this path compares well to historical observations. This climatological feature is a consequence of the seasonal availability of low salinity water over the MAFLA shelf and De Soto Canyon for entrainment into jets associated with the mesoscale eddy field in the northern GoM. Additionally, the chlorophyll a monthly climatology from satellite data shows elevated concentrations in a tongue‐like pattern similar to the low salinity feature found in the model, suggestive of a biological connection between the eastern GoM basin and river discharge in the northern GoM.
Rayleigh waves modeling using an elastic lattice model
Authors: del Valle‐García Raúl , Sánchez‐Sesma Francisco J.
Published: August 2003

The elastic lattice (percolation) model, used in statistical physics studies, has been quite successful in simulating dynamic fracture phenomena, including their associated acoustic emission. This discrete model is suitable for representing disordered media such as rocks. Thus, motivated by its advantages to deal with discontinuous realistic media, in comparison to the continuum theory, we performed simulations of elastic wave propagation by using a vector percolating network that includes central and bond‐bending force constants allowing local microscopic variation of the Poisson's ratio. The validity of the proposed approach is tested by comparing our numerical results with those from Garvin's exact analytical solution for a buried dilatational line source in a half space. In the free‐surface response the Rayleigh waves play a prominent role.
Improved estimates of the dynamical state of the North Pacific Ocean from a 4 dimensional variational data assimilation
Authors: Masuda Shuhei , Awaji Toshiyuki , Sugiura Nozomi , Ishikawa Yoichi , Baba Kinji , Horiuchi Kazutoshi , Komori Nobumasa
Published: August 2003

A 4‐dimensional variational data assimilation system has been used to better define the mean seasonal state of the North Pacific. The synthesis of available observational records and a sophisticated general circulation model produces a dynamically consistent time‐varying dataset which exhibits realistic features of the global ocean circulation and requires no artificial sources or sinks for the temperature and salinity fields. The dataset enables us to clarify the water mass formation and movement processes. A sensitivity experiment using our system reveals that the origin of the North Pacific Intermediate Water can be traced back to the Okhotsk and Bering Seas in the subarctic region and to the subtropical Kuroshio region further south, consistent with recent observational findings. This result illustrates that the ocean state derived from our data assimilation has greater information and forecast potential than that obtained from earlier methods.
Observations of the geopause at the equatorial magnetopause: Density and temperature
Authors: Chandler Michael O. , Moore Thomas E.
Published: August 2003

Magnetic flux tubes containing plasmaspheric ion density and composition have been observed in the region between the classical plasmapause and the magnetopause. New observations show that these ion distributions exist at the equatorial, post‐noon magnetopause. Comparison to observations of similar distributions at geosynchronous orbit and to simulations leads to the conclusion that these ions are convected from these regions to the magnetopause. This represents an extension of the geopause to the outer edge of the magnetosphere on the dayside. The presence of ion densities >10cm−3 in this region must have profound impact on the nature of plasma processes that occur there.
Pre‐breeding energy requirements: thyroid hormone, metabolism and the timing of reproduction in house sparrows Passer domesticus
Authors: Chastel Olivier , Lacroix André , Kersten Marcel
Published: August 2003

We measured thyroid hormone (T3) levels and energy expenditure of pre‐breeding house sparrows Passer domesticus in relation to the timing of breeding and reproductive success. The onset of reproduction was synchronised in two waves, separated by a three‐week interval. On an annual basis, early breeders (birds that bred for the first time during the first wave) made significantly more breeding attempts, laid significantly more egg and raised 2.3 times more chicks to fledging than late breeders (birds that bred for the first time during the second wave). By the end of March, about one month before the first egg was laid in the population, plasma titres of testosterone in males and estradiol in females were still low and did not differ between early and late breeders. However, birds that subsequently bred early had higher titres of plasma triiodothyronine (T3) than birds that started to breed late. We show for the first time in a free‐living bird population that Basal Metabolic Rate (BMR) is positively correlated with the plasma titre of T3. Differences in plasma T3 accounted for 48% of the inter‐individual variation in BMR. Elevated T3 levels indicate that energy requirements increase prior to breeding. Although early breeding appears to be advantageous in terms of the number of offspring raised on an annual basis, the increased energy requirements prior to breeding are thought to delay the onset of reproduction in those birds that cannot afford the additional energy expenditure early in the season.
Use of trace elements in feathers of sand martinRiparia ripariafor identifying moulting areas
Authors: Szép Tibor , Møller Anders Pape , Vallner Judit , Kovács Béla , Norman David
Published: August 2003

We investigated whether trace elements in tail feathers of an insectivorous and long‐distance migratory bird species could be used to identify moulting areas and hence migratory pathways. We analysed tail feathers from birds of different age and sex collected from a range of different breeding sites across Europe. The site of moult had a large effect on elemental composition of feathers of birds, both at the European and African moulting sites. Analysis of feathers of nestlings with known origin suggested that the elemental composition of feathers depended largely upon the micro‐geographical location of the colony. The distance between moulting areas could not explain the level of differences in trace elements. Analysis of feathers grown by the same individuals on the African wintering grounds and in the following breeding season in Europe showed a large difference in composition indicating that moulting site affects elemental composition. Tail feathers moulted in winter in Africa by adults breeding in different European regions differed markedly in elemental composition, indicating that they used different moulting areas. Analysis of tail feathers of the same adult individuals in two consecutive years showed that sand martins in their first and second wintering season grew feathers with largely similar elemental composition, although the amounts of several elements in tail feathers of the older birds was lower. There was no difference between the sexes in the elemental composition of their feathers grown in Africa. Investigation of the trace element composition of feathers could be a useful method for studying similarity among groups of individuals in their use of moulting areas.
Does foraging behaviour explain the poor breeding success of great tits Parus major in northern Europe?
Authors: Rytkönen Seppo , Krams Indrikis
Published: August 2003

Great tits Parus major have generally much poorer breeding success in northern Finland than in mid‐ and western Europe. The aim of this study is to find out whether the poor success is linked to foraging behaviour. This was studied by monitoring great tits' foraging behaviour and food abundance in different substrates during the breeding cycle in two populations, N Finland (65°N) and Latvia (56°N). It was shown that breeding success, from eggs to fledglings, was significantly poorer (56% vs. 93%) and caterpillar abundance considerably lower in the northern population. The general patterns in foraging behaviour were the same in N Finland and Latvia (especially the preference of birches Betula spp.) indicating that great tits used basically the same species‐typical foraging strategy in both populations. However, thin branches of birch were preferred in the north but avoided in Latvia, which may suggest that northern great tits have changed their foraging niche towards the outer parts of canopy, a niche typically occupied by the blue tit. This shift is theoretically advantageous, since the outer parts of the canopy are the richest caterpillar source. In practice, however, the poorer success of great tits indicates that this is not a beneficial strategy. Primarily, great tits in the northern population seem to be food limited since they lay too large clutches in relation to accessible food resources. This may be because great tits are not adapted to lower caterpillar production in the northern margins of their distribution and cannot change their narrow diet (3/4 caterpillars), like e.g. willow tits can. In search for caterpillars, food accessibility is further limited because the great tits' normal foraging behaviour, with wide search radius, may not function properly in the denser, outer parts of the canopy. Great tits may also be too heavy to forage efficiently on leafed twigs.
Nest site selection by yellow‐faced honeyeaters Lichenostomus chrysops
Authors: Boulton Rebecca L. , Cassey Phillip , Schipper Clinton , Clarke Michael F.
Published: August 2003

When choosing subsequent nest sites, species that produce multiple broods in a single breeding season have the option of dispersing from a site where they previously suffered depredation, i.e., a predator‐avoidance tactic. In our study on yellow‐faced honeyeaters Lichenostomus chrysops it was found that 89% of nest failures were attributed to nest depredation, the primary cause of reproductive failure. Pairs re‐nested further from depredated nesting attempts than from successful nesting attempts and progressively higher above the ground as the breeding season progressed. Pairs nesting in dioecious Coprosma quadrifida plants only nested in non‐fruiting male plants. Artificial nests were used to test the hypothesis that nest height and plant preferences were strategies to reduce the risk of depredation. There was no evidence that either higher nests or nests in non‐fruiting C. quadrifida achieved reduced levels of depredation during 14 days of artificial nest exposure. Specific nest site characteristics were not found to be associated with nest outcome for either natural or artificial nests. Our study provides further evidence that species may choose a diverse range of nest sites in order to avoid predators from developing specific search images and then, following depredation, compensate by rapidly re‐nesting away from the failed attempt.
Sex‐specific hatching order, growth rates and fledging success in jackdaws Corvus monedula
Authors: Arnold Kathryn E. , Griffiths Richard
Published: August 2003

In the jackdaw Corvus monedula, eggs hatch asynchronously with the youngest chicks in the brood often starving to death. So far, it is unknown whether there are sex differences in vulnerability to starvation. Adult females are smaller than males suggesting that daughters should be cheaper to produce than sons and so, less likely to starve when nest conditions are poor. Here, we determine whether sex, laying order and season interact to influence growth and fledging success. In a nestbox population of jackdaws, we found a non‐significant female bias at both hatching (112:120) and fledging (37:52). Generalised linear models revealed that parents seemed to be investing differently in sons and daughters depending on their chances of success. Broods produced late in the season were significantly female biased, particularly those from small clutches. Females hatched towards the end of the season, when conditions were poor, were more likely to fledge than males. Nestlings that were relatively large at hatching were more likely to fledge. This effect was particularly important for last hatched individuals. Overall, males had a higher mortality rate than females. The most likely cause was starvation due to higher energetic requirements, because males were larger than females at fledging. We suggest that in species with brood reduction, sex‐biased mortality may be at least as important as primary sex ratio manipulation in determining avian sex ratios.