bluuebunny/crossref_metadata_2025 huggingface dataset:
Baroclinic tides in the Indonesian seas: Tidal fields and comparisons to observations
Authors: Robertson Robin , Ffield Amy
Published: July 2008

Barotropic and baroclinic tides were simulated for the Indonesia Seas using a primitive equation, terrain‐following coordinate model, the Regional Ocean Model System (ROMS) with four tidal constituents (M2, S2, K1, and O1). The region's intricate topography as well as interactions between the Pacific and Indian Ocean tides within the Indonesian Seas resulted in complex barotropic and baroclinic tidal fields. The semidiurnal tides entered from both the Pacific and Indian oceans converging in Makassar Strait and the Ceram Sea with an amphidromic point forming in the Timor Sea. Diurnal tides were dominated by the Pacific Ocean tide. The model successfully replicated the observed tidal elevation fields as determined from TOPEX/POSEIDON crossovers with better performance for the semidiurnal constituents, RMS differences of 4–6 cm, than the diurnal constituents, RMS differences of 7–10 cm. A baroclinic response was apparent in the elevations, and the locations of the observed baroclinic elevation response in TOPEX/POSEIDON data agreed with that of the model. Velocities were baroclinic for all constituents with high spatial variability, particularly near sills and in straits. Extensive interactions occurred in the internal tidal fields: between a beam and its own reflections, between internal tides generated at different locations (i.e., different sides of a channel, or beams generated nearby), and between the barotropic and baroclinic tidal beams. Owing to propagation, even regions >100 km from sills showed significant vertical and horizontal variability resulting from internal tides. This resulted in extremely complex internal tidal fields with high variability, both spatially and temporally during a tidal cycle.
An observational and numerical study of a regional‐scale downslope flow in northern Arizona
Authors: Savage L. Crosby , Zhong Shiyuan , Yao Wenqing , Brown William J. O. , Horst Thomas W. , Whiteman C. David
Published: July 2008

Boundary layer observations taken during the METCRAX field study in October of 2006 near Winslow in Northern Arizona revealed the frequent presence of a near‐surface wind maximum on nights with relatively quiescent synoptic conditions. Data from a sodar, a radar wind profiler, several surface stations, and frequent high‐resolution rawinsonde soundings were used to characterize this boundary layer wind phenomenon and its relation to synoptic conditions and the ambient environment. The data analyses are augmented by high‐resolution mesoscale numerical modeling. It is found that the observed nocturnal low‐level wind maximum is part of a regional‐scale downslope flow converging from high terrain of the Colorado Plateau toward the Little Colorado River Valley. The depth of this downslope flow is between 100 and 250 m with a peak speed of 4–6 m s−1occurring usually within the lowest 50 m above ground. Opposing ambient winds lead to a longer evening transition period, shallower slope flows, and a smaller horizontal extent as compared to supporting synoptic winds. A simple analytical solution based on local equilibrium appears to agree fairly well with the observed layer mean downslope wind speed, but the classic Prandtl solution for maximum downslope wind speed fails to match the observations. The properties of the flow appear to be insensitive to changes in soil moisture, land cover, and surface roughness length. The contribution to the low‐level wind maximum by inertial oscillation at night is found to be insignificant.
POLDER2/ADEOSII, MISR, and MODIS/Terra reflectance comparisons
Authors: Lallart Pierre , Kahn Ralph , Tanré Didier
Published: July 2008

Reflectance differences among Multiangle Imaging Spectroradiometer (MISR), Moderate Resolution Imaging Spectroradiometer (MODIS)/Terra and Polarization and Directionality of the Earth's Reflectances (POLDER2) are characterized, as functions of observation geometry and spectral bands. For observations having similar geometry, corresponding normalized reflectances from MISR and MODIS fall within 3% for all bands except the MISR red band, which is higher than MODIS and POLDER2 by about 3.5%. POLDER2 and MODIS are within less than about 1% in the blue and red, 4% in the near‐infrared, and 5% in the green. Generally, MISR reflectances are at the high end of the reflectance envelope, whereas POLDER2 tends to be at the low end, yielding a spread of about 5% in the red, 5% in the near‐infrared, and over 7% in the green. Reflectance differences were not quantitatively corrected for instrument‐to‐instrument spectral band pass differences because of the uncertainties associated with such calculations. However, these uncertainties are assessed, and the envelopes can be used to bound calibration contributions to derived geophysical quantity uncertainties, including aerosol amount and type. This is of particular importance when data from the three instruments are used together in geophysical applications.
Production, oxidation, and emissions of methane from rice fields in China
Authors: Khalil M. A. K. , Shearer M. J. , Rasmussen R. A. , Duan Changlin , Ren Lixin
Published: July 2008

Detailed field studies of methane emissions from rice fields show that when nitrogen fertilizers are used with intermittent irrigation the seasonal average flux is about 3 mg/m2/hr. When continuous flooding and organic material is added to the same fields, the emissions rise to nearly 30 mg/m2/hr. Production rates measured during the two years when both organic material and water were applied to these fields were found to be 60 and 90 mg/m2/hr in consecutive years. The fraction oxidized is calculated to be about 80% one year and 43% the next year. The results suggest that high organic fertilizer increases production, but may affect the emissions more by reducing oxidation. The data show that seasonally averaged emissions vary by up to factor of 2 among adjacent fields but the variability of production is only about 20%. Information obtained from the farmers suggests that there is a trend towards less use of organic manure as nitrogen fertilizers have become available and the occurrence of intermittent flooding has increased for various reasons. These conditions have likely led to decreasing emissions of methane from rice fields in China in the recent decades.
Amazon rain forest subcanopy flow and the carbon budget: Santarém LBA‐ECO site
Authors: Tóta Julio , Fitzjarrald David R. , Staebler Ralf M. , Sakai Ricardo K. , Moraes Osvaldo M. M. , Acevedo Otávio C. , Wofsy Steven C. , Manzi Antonio O.
Published: July 2008

Horizontal and vertical CO2 fluxes and gradients were made in an Amazon tropical rain forest, the Tapajós National Forest Reserve (FLONA‐Tapajós: 54°58′W, 2°51′S). Two observational campaigns in 2003 and 2004 were conducted to describe subcanopy flows, clarify their relationship to winds above the forest, and estimate how they may transport CO2 horizontally. It is now recognized that subcanopy transport of respired CO2 is missed by budgets that rely only on single point eddy covariance measurements, with the error being most important under nocturnal calm conditions. We tested the hypothesis that horizontal mean transport, not previously measured in tropical forests, may account for the missing CO2 in such conditions. A subcanopy network of wind and CO2 sensors was installed. Significant horizontal transport of CO2 was observed in the lowest 10 m of the canopy. Results indicate that CO2 advection accounted for 73% and 71%, respectively, of the carbon budget for all calm nights evaluated during dry and wet periods. We found that horizontal advection is likely important to the canopy CO2 budget even for conditions with the above‐canopy friction velocity higher than commonly used thresholds.
Observations and modeling of a pulsating density current
Authors: Biton E. , Silverman J. , Gildor H.
Published: July 2008

We investigate density current formation and flow in the northern Gulf of Eilat, Red Sea, using in situ observations and a high resolution, nonhydrostatic general circulation model. These density currents occur in relatively warm water ∼20°C and are probably the warmest in the world ocean. We demonstrate the intrinsic nonlinearity of density currents by comparing two high‐resolution simulations forced by different heat flux. This nonlinearity, which is poorly represented in global models, is shown here to affect the properties of simulated density currents. Such a bias in simulating density currents in global models may lead to significant biases on the larger scale global ocean circulation and water mass distribution.
Interhemispheric thermal gradient and tropical Pacific climate
Authors: Chiang John C. H. , Fang Yue , Chang P.
Published: July 2008

We explore the impact of interhemispheric thermal gradients forcing on the tropical Pacific ocean‐atmosphere climate in an intermediate coupled model. The equatorial zonal sea surface temperature (SST) gradient strengthens with an increased northward interhemispheric thermal gradient, the increase arising from earlier onset and later retreat of the seasonal cold tongue, and intensification during the peak cold season. When the mean interhemispheric thermal gradient is reversed, the central equatorial Pacific SST annual cycle abruptly reverses in phase, with its cold season in Mar–May rather than Sep–Nov. While startling, this response is consistent with a prevailing hypothesis that ties the cold tongue SST annual cycle phase to the hemispheric mean asymmetry of the Intertropical Convergence Zone. El Niño‐Southern Oscillation activity is also sensitive to the interhemispheric thermal gradient, with peak activity occurring when the mean gradient is small, reducing rapidly as the mean gradient increases in either direction.
Annual period temperature and salinity signals of surface waters in Prince William Sound, Alaska
Authors: Okkonen Stephen R. , Bélanger Claude
Published: July 2008

Temperature and salinity measurements acquired during thermosalinograph surveys conducted throughout Prince William Sound (PWS) between March 2006 and January 2008 are used to identify annual period temperature and salinity signals of surface waters. Mean states and annual period changes in oceanic conditions throughout PWS reflect proximity to glaciated watersheds. Mean temperatures are coolest in northern and western PWS and warmest in southeastern PWS. Annual period temperature amplitude is greatest in western PWS. Mean salinities are lowest in northern and western PWS and highest in central and southeastern PWS. Annual period salinity amplitude is greatest in northern and western PWS. These results represent the most spatially comprehensive descriptions to date of annual period temperature and salinity signals in PWS. The results are applicable as benchmarks for validation of numerical PWS circulation models and as a decision support tool for the use of dispersants in the event of an oil spill.
Mechanisms of oxygen sensing: a key to therapy of pulmonary hypertension and patent ductus arteriosus
Authors: Weir E K , Obreztchikova M , Vargese A , Cabrera J A , Peterson D A , Hong Z
Published: July 2008

Specialized tissues that sense acute changes in the local oxygen tension include type 1 cells of the carotid body, neuroepithelial bodies in the lungs, and smooth muscle cells of the resistance pulmonary arteries and the ductus arteriosus (DA). Hypoxia inhibits outward potassium current in carotid body type 1 cells, leading to depolarization and calcium entry through L‐type calcium channels. Increased intracellular calcium concentration ([Ca++]i) leads to exocytosis of neurotransmitters, thus stimulating the carotid sinus nerve and respiration. The same K+channel inhibition occurs with hypoxia in pulmonary artery smooth muscle cells (PASMCs), causing contraction and providing part of the mechanism of hypoxic pulmonary vasoconstriction (HPV). In the SMCs of the DA, the mechanism works in reverse. It is the shift from hypoxia to normoxia that inhibits K+channels and causes normoxic ductal contraction. In both PA and DA, the contraction is augmented by release of Ca++from the sarcoplasmic reticulum, entry of Ca++through store‐operated channels (SOC) and by Ca++sensitization. The same three ‘executive’ mechanisms are partly responsible for idiopathic pulmonary arterial hypertension (IPAH). While vasoconstrictor mediators constrict both PA and DA and vasodilators dilate both vessels, only redox changes mimic oxygen by having directly opposite effects on the K+channels, membrane potential, [Ca++]iand tone in the PA and DA. There are several different hypotheses as to how redox might alter tone, which remain to be resolved. However, understanding the mechanism will facilitate drug development for pulmonary hypertension and patent DA.

British Journal of Pharmacology(2008)155, 300–307; doi:10.1038/bjp.2008.291; published online 21 July 2008
Atypical pharmacologies at β‐adrenoceptors
Authors: Summers R J
Published: July 2008

β‐Adrenoceptors are one of the most widely studied groups of G‐protein‐coupled receptors but continue to provide surprises and insights that have general relevance to pharmacology. Atypical pharmacologies have been described for ligands formerly (and still) described as antagonists acting at β1‐, β2‐ and β3‐adrenoceptors that involve ligand‐directed signalling and possibly allosteric interactions at the receptors. In the article by Ngala et al., in this issue of the Br J Pharmacol, another example of atypical interactions with β‐adrenoceptors is described, this time for agonists. Some of the responses to BRL37344 and clenbuterol can be explained in terms of actions at β2‐adrenoceptors, whereas others such as the increased glucose uptake and palmitate oxidation observed with pM concentrations of BRL37344 may involve interactions with other (possibly allosteric) sites. Atypical pharmacologies of ligands acting at β‐adrenoceptors have already indicated new ways in which ligands can interact with G‐protein‐coupled receptors and these mechanisms are likely to have important consequences for future drug development.

British Journal of Pharmacology (2008) 155, 285–287; doi:fn1; published online 21 July 2008
Respiratory, postural and spatio-kinetic motor stabilization, internal models, top-down timed motor coordination and expanded cerebello-cerebral circuitry: a review
Authors: Skoyles John
Published: July 2008

Human dexterity, bipedality, and song/speech vocalization in Homo are reviewed within a motor evolution perspective in regard to (i) brain expansion in cerebello-cerebral circuitry, (ii) enhanced predictive internal modeling of body kinematics, body kinetics and action organization, (iii) motor mastery due to prolonged practice, (iv) task-determined top-down, and accurately timed feedforward motor adjustment of multiple-body/artifact elements, and (v) reduction in automatic preflex/spinal reflex mechanisms that would otherwise restrict such top-down processes. Dual-task interference and developmental neuroimaging research argues that such internal modeling based motor capabilities are concomitant with the evolution of (vi) enhanced attentional, executive function and other high-level cognitive processes, and that (vii) these provide dexterity, bipedality and vocalization with effector nonspecific neural resources. The possibility is also raised that such neural resources could (viii) underlie human internal model based nonmotor cognitions.
Evaluation of automated and conventional microarray hybridization: a question of data quality and best practice?
Authors: Peeva Violet K. , Lynch Jessica L. , DeSilva Christopher J. S. , Swanson Nigel R.
Published: July 2008

Microarray is a widely used technique to study gene expression. The increasing interest in the technology has resulted in increased availability of commercial accessory reagents and instrumentation. In principle, commercial advances in reagents, kits and equipment should greatly improve assay performance, since they each bring a measure of quality assurance and uniformity to the data above that which may be obtained from the original manual hybridization processes. However, independent validation of this perceived benefit remains an essential part of the adoption process and, in microarrays, this has often been overlooked for want of immediate convenience. We describe here the comparative evaluation of two automated hybridization instruments, namely the MAUI® (microarray user interface) hybridization system and the GeneTAC HybStation, against the conventional manual coverslip hybridization methodology. Our results show that there is a significant advantage in using automated hybridization instrumentation over the diffusion‐based coverslip methodology. We observed an enhancement of the mean signal, signal‐to‐noise ratio, and reproducibility between replicates when using both the MAUI® hybridization system and the GeneTAC HybStation. Automation further reduced labour time, offered simplicity and greater reproducibility and accuracy in the results. The present study has independently validated the benefits automation brings to the microarray hybridization process and highlights the differences between the instruments examined. We further comment on the higher quality of spot morphology when hybridization is performed at a lower temperature in combination with our buffer of choice.
A novel bivalent single‐chain variable fragment (scFV) inhibits the action of tumour necrosis factor α
Authors: Liu Mengyuan , Wang Xiangbin , Yin Changcheng , Zhang Zhong , Lin Qing , Zhen Yongsu , Huang Hualiang
Published: July 2008

Suppression of TNFα (tumour necrosis factor α) activity is widely considered to be among the most efficient treatments available for chronic inflammatory diseases. Here, a bivalent scFv (single‐chain variable fragment) fragment, named TNF‐BAb, was engineered by fusing two anti‐TNFα scFV fragments in tandem via a long and flexible linking peptide derived from human serum albumin and produced in functional form from Escherichia coli inclusion bodies. The bioactivity assays demonstrated that TNF‐BAb gained enormously in avidity and showed a much stronger ability to inhibit the biological action of TNFα, indicating that TNF‐BAb may become a good candidate for anti‐TNFα therapy.
Shifting from clonal to sexual reproduction in aphids: physiological and developmental aspects
Authors: Le Trionnaire Gaël , Hardie Jim , Jaubert‐Possamai Stéphanie , Simon Jean‐Christophe , Tagu Denis
Published: July 2008

Developmental biology is one of the fastest growing and fascinating research fields in life sciences. Among the wide range of embryonic development, a fundamental difference exists between organisms with sexual or asexual development. Aphids are unusual organisms which display alternative pathways of sexual and asexual development, the orientation of the pathway being determined by environmental conditions. These insects offer an adapted system in which to study developmental plasticity, because a side‐by‐side comparison of sexual and asexual development can be made in individuals with the same genotype. In this review, we describe the developmental mechanisms that have evolved in aphids for alternative sexual and asexual reproduction. In particular, we discuss how environmental cues orientate the reproductive mode of aphids from signal perception to endocrine regulation, and propose a comparative analysis of sexual and asexual gametogenesis and embryogenesis, which has been possible due to the development of molecular methods. As a result of the recent development of genomic resources in aphids, we expect these species will permit major advances in the study of the genomic basis underlying the choice of developmental fate and multiple reproduction strategies.
Linking Location Attractiveness and Tourist Intention
Authors: Cho Vincent
Published: July 2008

Location attractiveness, which concerns the overall perception of a location, is a dominant factor that drives travellers to a destination. Past studies mainly focused on the underlying antecedents that influence the attractiveness of a location. This paper sheds light on a theoretical model relating to the impact of location attractiveness. From behavioural—intention theories and goal-directed theories, we design a theoretical framework that the intention may be predicted by underlying beliefs on perceived location attractiveness, effort expectancy, social norms, and self lifestyle fit.
Vibrational modes of metal nanoshells and bimetallic core-shell nanoparticles
Authors: Kirakosyan Arman S. , Shahbazyan Tigran V.
Published: July 2008

We theoretically study the spectrum of radial vibrational modes in composite metal nanostructures such as bimetallic core-shell particles and metal nanoshells with dielectric core in an environment. We calculate frequencies and damping rates of fundamental (breathing) modes for these nanostructures along with those of two higher-order modes. For metal nanoshells, we find that the breathing mode frequency is always lower than the one for solid particles of the same size, while the damping is higher and increases with a reduction in the shell thickness. We identify two regimes that can be characterized as weakly damped and overdamped vibrations in the presence of external medium. For bimetallic particles, we find periodic dependence of frequency and damping rate on the shell thickness with period being determined by the mode number. For both types of nanostructures, the frequency of higher modes is nearly independent of the environment, while the damping rate shows a strong sensitivity to the outside medium.
H
4
+
: What do we know about it?
Authors: Alijah Alexander , Varandas António J. C.
Published: July 2008

The potential energy surface of H4+ has been analyzed and stationary points and minima of intersections characterized by benchmark multireference configuration interaction calculations with basis sets as large as augmented septuble zeta. No evidence for minima other than those of the well established stable C2v configuration has been found. Some of the results obtained previously at a lower level of ab initio theory had to be revised.
Quantum theory of chemical reactions in the presence of electromagnetic fields
Authors: Tscherbul T. V. , Krems R. V.
Published: July 2008

We present a theory for rigorous quantum scattering calculations of probabilities for chemical reactions of atoms with diatomic molecules in the presence of an external electric field. The approach is based on the fully uncoupled basis set representation of the total wave function in the space-fixed coordinate frame, the Fock–Delves hyperspherical coordinates, and the adiabatic partitioning of the total Hamiltonian of the reactive system. The adiabatic channel wave functions are expanded in basis sets of hyperangular functions corresponding to different reaction arrangements, and the interactions with external fields are included in each chemical arrangement separately. We apply the theory to examine the effects of electric fields on the chemical reactions of LiF molecules with H atoms and HF molecules with Li atoms at low temperatures and show that electric fields may enhance the probability of chemical reactions and modify reactive scattering resonances by coupling the rotational states of the reactants. Our preliminary results suggest that chemical reactions of polar molecules at temperatures below 1 K can be selectively manipulated with dc electric fields and microwave laser radiation.
Atomistic structure dependence of the collective excitation in metal nanoparticles
Authors: Negre Christian F. A. , Sánchez Cristián G.
Published: July 2008

From a simple time-dependent tight-binding model, we calculate the absorption spectra of a series of metallic nanoparticles of varying size and shape. Spheres and spheroids of varying aspect ratios as well as a number of polyhedral particle shapes are studied. The frequency of the maximum absorption is found to scale linearly with the surface to volume ratio of the particle with a slope and intercept, which depends on particle shape, in particular, on the deviation from sphericity. In the case of spheroids, the shifts of the two different plasmon peaks that are observed are characterized as a function of the aspect ratio. The influence of shape is seen to be a determining factor for the frequency of the plasmon resonance. The influence of adatoms is studied. Linear relations between surface adatom concentration and the width of the spectral feature as well as the peak energy are observed.
The Effect of Warming Winter Temperatures on the Severity of Pierce's Disease in the Appalachian Mountains and Piedmont of the Southeastern United States
Authors: Anas Osama , Harrison Una Jean , Brannen Phillip M. , Sutton Turner B.
Published: July 2008

Pierce's disease (PD) caused by Xylella fastidiosa (Xf) is a major threat to the rapidly growing Vitis vinifera/French-American hybrid winegrape industry in the southeastern United States. The bacterium, which is transmitted by xylemfeeding insects, is unable to survive low winter temperatures, and infected vines often recover the next year. Maps available from the 1970s indicate that PD is not a serious threat in the southeastern US, where the average minimum January temperature is ≤ 1.7°C. However PD symptoms developed in many vineyards planted in the late 1990s in areas identified as low risk. Surveys conducted in North Carolina and Georgia confirmed the presence of Xf in symptomatic vines using ELISA kits. Weather data for November to March from 84 weather stations from 1972-2005 for Alabama, Georgia, North Carolina, South Carolina, Tennessee, and Virginia were used to construct new maps using ArcGIS 9.1, and PD survey data from vineyards were superimposed on the maps. Areas for low risk for PD corresponded most closely with a minimum winter temperature of ≤ -12.2°C for 2 to 3 days or ≤ -9.4°C for 4 to 5 days. Warm winter temperatures during the last 8 years have resulted in a significant shift in the isotherms towards the north and west, increasing the risk of PD in the Piedmont region of the Southeast, and have extended the threat into Virginia and Tennessee.

Accepted for publication 11 March 2008. Published 18 July 2008.
Morphological criteria to identify faecal pellets of sympatric ungulates in West African savanna and estimates of associated error
Authors: Hibert Fabrice , Fritz Hervé , Poilecot Pierre , Abdou Hama Noma , Dulieu Dominique
Published: July 2008

Indirect surveys may prove to be useful tools in complementing classical direct counts when monitoring ungulate populations and may also promote better understanding of the precise structure and functioning of the rich ungulate communities of African savannas. However, the identification of faecal pellets can be difficult where several sympatric species occur. This study develops simple field criteria for distinguishing between pellets among ten sympatric West African ungulates. A discriminant analysis was performed, using the mean of measurements of pellet groups from different species to pinpoint and characterize the most useful morphological criteria for separation between them. The mean diameter of pellets within each pellet group proved to be the most valuable variable for species segregation, whilst the second axis separated species by mean indent depth. The pellet groups of six of the ten designated species could be identified with a minimum misclassification error. However, no simple morphological variables emerged to permit discrimination between hartebeest and topi, or between bushbuck and Bohor reedbuck pellets. Once pellet groups have been identified, their density and spatial distribution may provide useful information on the use of space and habitat of sympatric species, over given periods.
The Soft Seal disposable laryngeal mask airway in adults: comparison of two insertion techniques without intra‐oral manipulation
Authors: Kuvaki B. , Küçükgüçlü S. , İyilikçi L. , Tuncali B. E. , Çinar Ö.
Published: July 2008

We investigated whether insertion of the disposable Soft Seal laryngeal mask airway (SSLM) was successful without intra‐oral digital manipulation. One hundred patients undergoing anaesthesia using the SSLM were randomly assigned into two groups. Insertion was performed by either a direct or a rotational technique, both without intra‐oral digital manipulation. The primary outcome measure was successful insertion at first attempt. Other outcomes included insertion time, fibreoptic assessment of the airway view and airway morbidity. The first attempt success rate was higher (98%) with the direct technique than with the rotational technique (75%; p = 0.002) but insertion time was faster with the latter method (mean [range] 15 [8–50] s) than with the direct method (20 [8–56] s; p = 0.035). Fibreoptic assessment and airway morbidity were similar in both groups. We conclude that the SSLM can be successfully inserted without intra‐oral digital manipulation.
Quantitative trait loci for production traits in pigs: a combined analysis of two Meishan × Large White populations
Authors: Guo Y.‐M. , Lee G. J. , Archibald A. L. , Haley C. S.
Published: July 2008

Combined analysis of data from two or more resource populations can improve the power and accuracy of QTL mapping and allow some cross‐validation of results. In this study, we performed a genome‐wide scan using combined data from two F2 populations derived from a cross between Large White and Chinese Meishan pigs. A total of 739 pigs were included in the analysis. In total 187 markers were genotyped in the two populations, including 115 markers genotyped in both populations, and these markers covered 2282 cM of the pig genome with an average of 13.58 cM between markers. Seven traits (teat number, birth weight, weaning weight, test‐end weight, fat depth at shoulder, fat depth at mid back and fat depth at loin) were analysed for both individual populations and the combined population. There were 9 (2, 10), 1 (4, 4) and 14 (5, 18) QTL that achieved 1% genome‐wide, 5% genome‐wide and suggestive significance levels respectively in population 1 (population 2, combined population). Additive effects of QTL detected in the two populations at all significance levels were largely consistent suggesting that the QTL represent real genetic effects, but this was not the case for dominance or imprinting effects. There were also a number of significant interactions between detected QTL effects and population.
Up‐regulated cytokine‐inducible SH2‐containing protein expression in allergen‐stimulated T cells from hen's egg‐allergic patients
Authors: Nakajima Y. , Tsuge I. , Kondo Y. , Komatsubara R. , Hirata N. , Kakami M. , Kato M. , Kurahashi H. , Urisu A. , Asano Y.
Published: July 2008

Background
Although changes in the fine balance of allergen‐specific T cells are crucial in the pathogenesis of allergic diseases, their roles in the allergic reaction to hen's eggs (HE) have not yet been fully analysed.

Objective
Using microarray technology, allergen‐stimulated T cells from HE‐allergic children were analysed to identify genes that are specifically up‐regulated in these cells.

Methods
RNA from CD4+ CD14− cells, fractionated from allergen‐stimulated peripheral mononuclear cells, was analysed using a whole ‐genome microarray and real‐time RT‐PCR. The protein expression of selected genes was ascertained by flow cytometry.

Results
In microarray analyses of allergen‐stimulated T cells, 43 genes were up‐regulated in HE‐allergic children but not in non‐HE‐allergic children. Among these, up‐regulation of three genes, cytokine ‐inducible SH2‐containing protein (CISH), nuclear factor of κ light polypeptide gene enhancer in B‐cell inhibitor Z (NFKBIZ) and B‐cell CLL/lymphoma 2 (BCL2), was confirmed by real‐time quantitative RT‐PCR. CISH, but not NFKBIZ or BCL2, showed a significantly higher ratio of antigen‐stimulated cell transcription over unstimulated cells in HE‐allergic than in non‐HE‐allergic children (P<0.01). Flow‐cytometric analysis revealed that the percentage of CD25+CISH+ cells in CD4+ cells from patients with HE allergy was significantly higher than that in controls (P<0.01). The expression level of CISH was significantly higher in IL‐4+ Th2 cells than in IFN‐γ+ Th1 cells.

Conclusion
We noted that CISH expression in allergen‐stimulated CD4+ T cells from HE‐allergic patients was significantly increased in both mRNA and protein levels compared with that from non‐HE‐allergic children.
Control of cytokine gene transcription in Th1 and Th2 cells
Authors: Bowen H. , Kelly A. , Lee T. , Lavender P.
Published: July 2008

Analysis of T‐helper cell differentiation to T‐helper type 1 (Th1) and Th2 lineages has begun to reveal a complex mechanism whereby transcription factors, enzymes that either deposit or remove covalent modifications from histone tails and DNA methylating enzymes are recruited to cytokine genes. Each resultant cell lineage subsequently displays a programme of transcriptional restrictions that firstly, facilitates expression of a particular subset of signature cytokines and secondly, silences expression of the cytokines normally recognized as being markers of the opposite differentiation limb. Some essential proteins in this differentiative paradigm, such as the transcription factors GATA3 and T‐bet, are well studied; however, the types of enzymatic activities that these proteins recruit in order to implement differentiation are more obscure. Recent genome‐wide studies of histone modifications have begun to clarify how specific modifications of histones impact upon both transcriptional regulation and chromatin organization. Here we review how this information has enlightened our knowledge of how Th1/Th2 differentiation is orchestrated.
Some problems and solutions in density estimation from bearing tree data: a review and synthesis
Authors: Bouldin Jim
Published: July 2008

Aim  I detail several problems and solutions related to estimating pre‐settlement forest density from land surveyors’ bearing tree data. The data have a high value, so clarification of existing problems is needed in the development of a better theoretical framework in which to treat them. I focus on absolute density because it is the foundation for several other variables, e.g. basal area, timber volume and carbon content.

Location  The issues raised are relevant to the vast area encompassed by rectangular land surveys, including the General Land Office survey area of the United States (roughly, Ohio and Florida to the Pacific coast and Alaska), as well as significant areas in the eastern United States, and possibly elsewhere.

Methods  A literature review details the history and nature of density estimation from bearing tree data, and spatial simulations quantify the effects of certain identified problems on density estimates. The review focuses on methodological issues appearing in the ecological and biometrical literature.

Results  Problems encountered in the literature and addressed here include: (1) aggregated tree spatial patterns and their effect on density using traditional estimators; (2) the mis‐designation of bearing tree labels in relation to definitions given in the estimators; (3) biases due to small sample size; and (4) surveyor‐induced biases. Simulations of aggregated tree populations having a 44‐fold density variation show that estimates ranging from 5 to 127 per cent of actual can result, depending on the estimator used, the scale at which it is calculated, and the error in tree distance rank assignments. The traditionally used estimator is accurate only when trees are spatially random throughout, and sample size is not small. More robust estimators exist that can accommodate a wider range of variation in spatial pattern, sampling design and sample size. One of these is discussed in detail.

Main conclusions  Data users should pay much closer attention to critical aspects of bearing tree data and analytical methods, provide basic but necessary descriptive data, and more accurately represent the inherent range of possible errors of estimate. They can narrow this range of uncertainty by using the methods and considerations discussed here and in other recent work.
Step‐less models for regional environmental variation in Norway
Authors: Bakkestuen Vegar , Erikstad Lars , Halvorsen Rune
Published: July 2008

Aim  To assess the scale of variation for major environmental gradients in Norway. To obtain a step‐less model for this variation and to use this model to evaluate the extent to which the consensus expert classification of Norway into vegetation regions can be predicted from environmental variables. To discuss the potential of step‐less models for understanding natural variation at regional scales, for stratification and for predictive modelling of species distributions and land‐cover types.

Location  The mainland of Norway.

Methods  Fifty‐four climatic, topographical, hydrological and geological variables were recorded for grid cells with spatial resolution (grain size) of 1 × 1, 5 × 5 and 10 × 10 km, spanning the entire mainland of Norway. Principal components analyses (PCA) were used to summarize variation in three primary data matrices and three random subsets of these.

Results  The first four principal components explained between 75% and 85% of the variation in the data sets. All PCAs revealed four consistent environmental gradients, in order of decreasing importance: (1) regional variation (gradient) from coast to inland and from oceanic/humid to continental areas; (2) regional variation from north to south and from high to low altitudes; (3) regional variation from north to south and from inland to coast, related to solar radiation; and (4) topographic (terrain relief) variation on finer scales than (1–3).

The first two PCA axes corresponded to the two bioclimatic gradients used in expert classifications of Norway into biogeographical regions: vegetation sections (from highly oceanic to slightly continental) and vegetation zones (from nemoral to alpine).

Main conclusions  Our PCA analyses substantiate the current view of bioclimatic regional vegetation variation in Norway, provide an explicit characterization of this variation in terms of climatic variables, and show that environmental variability can be reproduced as GIS layers in step‐less models. These models have the potential to become important tools for future predictive modelling within resource management, conservation planning and biogeographical (and other ecological) research.
Phylogenetic relationships of assimineid gastropods of the Death Valley–lower Colorado River region: relicts of a late Neogene marine incursion?
Authors: Hershler Robert , Liu Hsiu‐Ping
Published: July 2008

Aim  A small fauna of amphibious snails (genus Assiminea Fleming, 1828) living in association with highly mineralized springs in the Death Valley–lower Colorado River region (DVLCR) is thought to be a relict of the Bouse Embayment, a putative late Miocene–early Pliocene transgression of the ancestral Gulf of California along the lower Colorado River valley. We analysed the phylogenetic relationships of this fauna using mtDNA sequence data (1171 bp) to determine whether, as would be consistent with this hypothesis, it forms a substantially divergent unit sister to marine coastal congeners.

Location  South‐western Great Basin and lower Colorado River region, USA.

Methods  Two genes [mitochondrial cytochrome c oxidase subunit I (COI) and the mitochondrial 16S ribosomal RNA gene] were sequenced for 10 populations of DVLCR assimineas (Assiminea infimaBerry, 1947; Assiminea sp.). We also sequenced an undescribed population from a spring in the Colorado River delta; western North American Pacific Coastal Assiminea californica (Tryon, 1865); the three other congeners that live on the continent; and three Old World assimineids (outgroups). Phylogenies based on the combined data set were obtained using Bayesian methods, and divergence times were estimated using a COI molecular clock for related gastropods.

Results  Composite haplotypes of the DVLCR assimineas, together with that observed in the Colorado River delta population, formed a weakly supported clade that was sister to a clade composed of populations of North American Pacific and Atlantic coastal species. The genetic distance between members of these two clades was 3.46 ± 0.47% for COI and 1.69 ± 0.38% for 16S. The former clade was composed of five subunits that differed from each other by 1.29–2.84% (COI) and 0.52–1.98% (16S) sequence divergence.

Main conclusions  Application of the COI clock suggests that progenitors of the DVLCR fauna diverged from coastal ancestors 2.13–1.89 Ma (late Pliocene), several million years after the Bouse Embayment would have been terminated by the establishment of the lower (freshwater) Colorado River. This finding, together with shallow genetic structuring of several DVLCR lineages that are widely distributed across the topographically complex regional landscape, suggests that the Assiminea fauna of this inland area was more likely to have been founded by coastal colonists transported on water birds than through a direct connection with the sea.
Coralligenous habitat in the northern Adriatic Sea: an overview
Authors: Casellato Sandra , Stefanon Antonio
Published: July 2008

The rocky outcrops irregularly scattered in the sandy‐muddy sea bed of the Northern Adriatic, formed by a base rock and a superimposed concretion of vegetal and animal organisms, are considered an infralittoral coralligenous habitat, according to the most recent definition. In the last four decades, research has mainly concentrated on their geology because of the question of the origin of the base rock – very similar to beachrock – which has only recently been attributed to sedimentary cementation induced by methane seeps. Studies on their macrobenthic assemblages have also been published recently, but true comparisons among them are difficult because they mostly refer only to a few selected phyla or to short‐term observations. Very few papers deal with the whole of the animal and plant communities, including all taxonomic groups and the most important environmental variables. On the basis of the literature data concerning several outcrops in the Gulf of Venice, we suggest that the Adriatic reefs differ slightly from the classic deeper coralligenous assemblages around the Mediterranean coast because they have smaller concretions of algae builders. We also suggest that the Northern Adriatic coralligenous reefs are younger than the other reefs occurring in the Mediterranean Sea.
Plasma volume replacement with HES 130/0.42 obviates negative side effects of pneumoperitoneum in piglets
Authors: OSTHAUS WILHELM ALEXANDER , HUBER DIRK , BÄUMKER CHRISTOPH , WITT LARS , METZELDER MARTIN , KUEBLER JOCHEN , SÜMPELMANN ROBERT
Published: July 2008

Background:  Evidence‐based guidelines on optimal perioperative fluid management in infants have not been established. Recent randomized trials in major abdominal surgery in adults suggest that large volumes of fluid may increase morbidity and hospital stay. Our own clinical experience in infants undergoing laparoscopic surgery is different. So the aim of this study was to compare a crystalloid vs a plasma volume stabilizing fluid management regime during prolonged pneumoperitoneum (PP) in an experimental setting.

Methods:  Fifteen German landrace piglets were randomized to one of the following treatment groups: control (no PP, 5 ml·kg−1·h−1 electrolyte solution); crystalloid (180 min of PP, 5 ml·kg−1·h−1 electrolyte solution); colloid (180 min of PP, single bolus of 5 ml·kg−1 followed by 5 ml·kg−1·h−1 hydroxyethyl starch 130/0.42/6:2). After decompression, monitoring was continued for a further 120 min. During the investigation, the hemodynamic situation including transpulmonary thermodilution and blood gases was monitored periodically.

Results:  During the study, mean arterial pressure remained within the normal range in colloid‐treated animals and controls, but was significantly lower in crystalloid‐treated animals after decompression of PP. Cardiac output remained within the normal range in the colloid and control groups, but decreased in the crystalloid‐treated animals. In the crystalloid group, the lactate concentrations were higher and base excess was lower than in the colloid and control groups at 240 and 300 min (study end).

Conclusion:  This study shows that the negative effects of prolonged PP on hemodynamics and acid–base balance can be obviated by a liberal plasma volume stabilization regimen with colloids.
An audit of intravenous fluid prescribing and plasma electrolyte monitoring; a comparison with guidelines from the National Patient Safety Agency
Authors: SNAITH ROSIE , PEUTRELL JANE , ELLIS DAVID
Published: July 2008

Objectives:  To audit past practice of intravenous (i.v.) fluid prescribing and electrolyte monitoring, prior to the publication of guidelines by the National Patient Safety Agency (NPSA, Ref. NPSA/2007/22) in March 2007, highlighting areas of discrepancy, in a specialist children’s hospital.

Methods:  We performed a retrospective case note review of 100 appendectomy patients between February 2004 and March 2007, recording; fluid type and volumes given as maintenance therapy, resuscitation boluses and nasogastric replacement; the frequency and timing of plasma electrolyte measurement; the relationship between plasma sodium [Na] concentration and i.v. fluid prescribed; and patient weight recordings.

Results:  Ninety‐eight acute appendectomies and two interval elective appendectomies. Median age 10 years (interquartile range: 8–11.25). Before surgery, hypotonic maintenance fluid was prescribed for 94% patients. During surgery, maintenance fluid was predominantly isotonic. After surgery, hypotonic maintenance fluid was prescribed for 92% patients. All maintenance fluid volumes were appropriately calculated according to weight using the Holliday and Segar formula (Paediatrics, 19, 1957, 823). Fluid boluses were isotonic on 128/129 occasions and all accurately calculated according to weight. Nasogastric losses were replaced with 0.9% sodium chloride. No patient had daily plasma electrolyte measurements whilst administered i.v. fluid. Twenty‐seven patients had recorded hyponatremia ([Na] <135 mmol·l−1; 21 at presentation, six subsequently after admission). Hypotonic maintenance fluid was continued in 26/27 patients with hyponatremia. No patient had daily weight recorded.

Conclusions:  Our practice of i.v. fluid prescribing and electrolyte monitoring in children, prior to the publication of guidelines by the NPSA in March 2007, did not fully meet the recommended standards.
A cohort evaluation of the pediatric ProSeal laryngeal mask airway in 100 children
Authors: KELLY FIONA , SALE STEVEN , BAYLEY GUY , COOK TIM , STODDART PETER , WHITE MICHELLE
Published: July 2008

Background:  The ProSeal® laryngeal mask airway (PLMA) has been available in pediatric sizes in the UK since 2007. Although several non‐UK studies have evaluated PLMAs in children, there are little published data regarding their use in this country. Having decided to introduce the pediatric PLMA into our practice, we chose to prospectively audit the first 100 uses as part of our clinical governance.

Methods:  We studied children undergoing elective surgery who were considered suitable for a supraglottic airway. We recorded patient, surgical and insertion details, device performance data and complications. Patient management was not altered by inclusion in this audit.

Results:  Twenty size 1.5, 55 size 2.0, 15 size 2.5 and 10 size 3.0 PLMAs were inserted in 100 consecutive children [median age 2 years (range 2 months to 10 years) and median weight 15 kg (range 4.9–60 kg)]. The overall first attempt success rate was 93% (size 1.5, 100%; size 2.0, 100%; size 2.5, 87%; size 3.0, 90%) and overall successful insertion rate was 99%. Median leak pressure was 25 cmH2O. Outright failure was seen in one patient; complications were seen in another six patients (partial airway obstruction in five patients and mild laryngospasm in one patient), all of whom were transient and none of whom required intubation. No episodes of regurgitation were recorded.

Conclusions:  Even without prior experience and using nonconventional insertion, pediatric PLMAs (including size 1.5) can be easily inserted and provide an effective airway.