bluuebunny/crossref_metadata_2025 huggingface dataset:
Demography and Cultural Innovation: a Model and its Implications for the Emergence of Modern Human Culture
Authors: Shennan Stephen
Published: August 2008

In recent years there has been a major growth of interest in exploring the analogies between the genetic transmission of information from one generation to the next and the processes of cultural transmission, in an attempt to obtain a greater understanding of how culture change occurs. This article uses computer simulation to explore the implications of a specific model of the relationship between demography and innovation within an evolutionary framework. The consequences of innovation appear far more successful in larger populations than in smaller ones. In conclusion, it is suggested that the model has major implications for the origins of modern human culture in the last 50,000 years, which may be seen not as the result of genetic mutations leading to improved cognitive capacities of individuals, but as a population consequence of the demographic growth and increased contact range which are evident at this time. It is also proposed that the model may be of general relevance for understanding the process of cultural evolution in modern and pre-modern humans.
Tool Standardization in the Middle and Upper Palaeolithic: a Closer Look (with comments)
Authors: Marks Anthony , Hietala Harold J. , Williams John K.
Published: August 2008

It has been postulated that one difference between Neanderthals and anatomically modern people lies in a ‘clearer mental template’ of flaked stone tools on the part of modern people. This is thought to have been manifested in greater tool standardization during the Upper Palaeolithic than in the Middle Palaeolithic. Testing of this hypothesis, using three samples of a characteristic Upper Palaeolithic tool class — burins — from one Middle Palaeolithic and two Upper Palaeolithic assemblages, reveals that they are equally standardized for both metric and non-metric traits. Further consideration suggests that most Palaeolithic flaked stone tools are poorly suited to test notions of standardization, although some tool attributes may be well suited when considered in specific adaptive contexts.
Decorating the Houses of the Dead: Incised and Pecked Motifs in Orkney Chambered Tombs
Authors: Bradley Richard , Phillips Tim , Richards Colin , Webb Matilda
Published: August 2008

Megalithic art has often been treated as a unitary phenomenon, related to the spread of farming across Western Europe. This approach does not do justice to the very different ways in which tomb decoration was employed by particular communities. This article focuses on the megalithic art of Orkney, much of it recorded for the first time during a recent field survey. This is normally interpreted as a local variant of the style of ‘art’ found in Neolithic Ireland, but on close examination it has much stronger links with the abstract motifs found in local settlements. Whereas the megalithic art of Ireland may have celebrated the passage of the dead to another world, in Orkney it was used to emphasize their continued involvement in the affairs of the living.
Rethinking ‘Cattle Cults’ in Early Egypt: Towards a Prehistoric Perspective on the Narmer Palette
Authors: Wengrow David
Published: August 2008

The Narmer Palette occupies a key position in our understanding of the transition from Predynastic to Dynastic culture in Egypt. Previous interpretations have focused largely upon correspondences between its decorative content and later conventions of élite display. Here, the decoration of the palette is instead related to its form and functional attributes and their derivation from the Neolithic cultures of the Nile Valley, which are contrasted with those of southwest Asia and Europe. It is argued that the widespread adoption of a pastoral lifestyle during the fifth millennium BC was associated with new modes of bodily display and ritual, into which cattle and other animals were incorporated. These constituted an archive of cultural forms and practices which the makers of the Narmer Palette, and other Protodynastic monuments, drew from and transformed. Taking cattle as a focus, the article begins with a consideration of interpretative problems relating to animal art and ritual in archaeology, and stresses the value of perspectives derived from the anthropology of pastoral societies.
Predictors of breast-feeding in a developing country: results of a prospective cohort study
Authors: Al-Sahab Ban , Tamim Hala , Mumtaz Ghina , Khawaja Marwan , Khogali Mustafa , Afifi Rima , Nassif Yolla , Yunis Khalid A ,   for the National Collaborative Perinatal Neonatal Network (NCPNN)
Published: August 2008

Objective

Data on the prevalence and predictors of breast-feeding remain scarce in Lebanon. Moreover, no study has previously addressed the effect of the paediatrician’s sex on breast-feeding. The present study aimed to assess the prevalence and predictors of breast-feeding at 1 and 4 months of infant age while exploring the potential role of the sex of the paediatrician.

Design

Prospective cohort study. Predictors of breast-feeding significant at the bivariate level were tested at 1 and 4 months through two stepwise regression models.

Setting

Infants were enrolled through the clinics and dispensaries of 117 paediatricians located in Beirut, Lebanon, and its suburbs.

Subjects

A total of 1320 healthy newborn infants born between August 2001 and February 2002 were prospectively followed during the first year.

Findings

Breast-feeding rates at 1 and 4 months were 56·3 % and 24·7 %, respectively. Early discharge, high parity and religion were significantly associated with higher breast-feeding rates at 1 and 4 months of age. Maternal age proved significant only at 1 month, while maternal working status and sex of the paediatrician were significant at 4 months. A novel finding of our study was the positive effect of female paediatricians on breast-feeding continuation until 4 months of age (OR = 1·49; 95 % CI 1·03, 2·15).

Conclusions

Breast-feeding rates are low at 1 and 4 months of infant age in Beirut. Further research to investigate the interactions between female physicians and lactating mothers in maintaining breast-feeding in other populations is warranted. The results constitute the basis for designing interventions targeting policy makers, health professionals and mothers.
Five-year changes in adiposity and cardio-metabolic risk factors among Guatemalan young adults
Authors: Gregory Cria O , Martorell Reynaldo , Venkat Narayan KM , Ramirez-Zea Manuel , Stein Aryeh D
Published: August 2008

Background

Rapidly transitioning societies are experiencing dramatic increases in obesity and cardio-metabolic risk; however, few prospective studies from developing countries have quantified these increases or described their joint relationships.

Methods

We collected dietary, physical activity, demographic, anthropometric and cardio-metabolic risk factor data from 376 Guatemalan young adults in 1997–98 (aged 20–29 years) and in 2002–04 (aged 25–34 years).

Results

In total, 42 % of men and 56 % of women experienced weight gain >5 kg in 5 years. Percent body fat (%BF) and waist circumference (WC) increased by 4·2 % points and 5·5 cm among men, and 3·2 % points and 3·4 cm among women, respectively. Five-year increases in both %BF and WC were associated with lower physical activity, urban residence and shorter height among men but not among women (test for heterogeneityP< 0·05 for residence and physical activity). Changes in %BF and WC and concomitant changes in cardio-metabolic risk factors were similar for men and women. In standardised regression, change in %BF was associated with changes in TAG (β=0·19; 95 % CI 0·08, 0·30), total:HDL cholesterol (β=0·22; 95 % CI 0·12, 0·33) and systolic (β=0·22; 95 % CI 0·12, 0·33) and diastolic (β=0·18; 95 % CI 0·08, 0·28) blood pressure, but not with glucose; associations were similar for WC.

Conclusions

Over 5 years this relatively young population of Guatemalan adults experienced rapid increases in multiple measures of adiposity, which were associated with adverse changes in lipid and blood pressure levels.
Yesterday’s dinner, tomorrow’s weather, today’s news? US newspaper coverage of food system contributions to climate change
Authors: Neff Roni A , Chan Iris L , Smith Katherine Clegg
Published: August 2008

Background

There is strong evidence that what we eat and how it is produced affects climate change.

Objective

The present paper examines coverage of food system contributions to climate change in top US newspapers.

Design

Using a sample of sixteen leading US newspapers from September 2005 to January 2008, two coders identified ‘food and climate change’ and ‘climate change’ articles based on specified criteria. Analyses examined variation across time and newspaper, the level of content relevant to food systems’ contributions to climate change, and how such content was framed.

Results

There were 4582 ‘climate change’ articles in these newspapers during this period. Of these, 2·4 % mentioned food or agriculture contributions, with 0·4 % coded as substantially focused on the issue and 0·5 % mentioning food animal contributions. The level of content on food contributions to climate change increased across time. Articles initially addressed the issue primarily in individual terms, expanding to address business and government responsibility more in later articles.

Conclusions

US newspaper coverage of food systems’ effects on climate change during the study period increased, but still did not reflect the increasingly solid evidence of the importance of these effects. Increased coverage may lead to responses by individuals, industry and government. Based on co-benefits with nutritional public health messages and climate change’s food security threats, the public health nutrition community has an important role to play in elaborating and disseminating information about food and climate change for the US media.
Relationship of parental characteristics and feeding practices to overweight in infants and young children in Beijing, China
Authors: Jingxiong Jiang , Rosenqvist Urban , Huishan Wang , Koletzko Bert , Guangli Lian , Jing Huang , Greiner Ted
Published: August 2008

Background

Childhood obesity has become a major public health problem in many countries. To explore the risk factors of overweight in infants and young children might be helpful in developing an early overweight intervention strategy.

Objective

To assess the prevalence of overweight and the relationship of parental characteristics and feeding practices to overweight in infants and young children in Beijing, China.

Design

Data on weight and length/height were collected on 4654 children aged 1–35 months in twelve communities in Beijing from a cross-sectional study. Overweight was defined as weight-for-length/height ≥2sdabove the median of the WHO reference. Two hundred and fifteen families with overweight children and 215 families with normal-weight children were interviewed using a questionnaire to obtain feeding practices.

Results

The overall prevalence of overweight was 4·7 %. Both parental overweight and low parental education were significantly higher among overweight than normal-weight children. The total energy intake was significantly higher in overweight than in normal-weight children at 12–35 months of age. Compared with normal-weight children, significantly fewer overweight children were breast-fed for at least 4 months. Overweight children were also more likely to have been introduced to infant formula and semi-solid foods during the first 4 months.

Conclusion

Early prevention strategies should include feeding practices identified as putting children at risk of obesity. These include early cessation of breast-feeding and premature introduction of other foods.
Sociodemographic and lifestyle characteristics are associated with antioxidant intake and the consumption of their dietary sources during pregnancy
Authors: Uusitalo Liisa , Uusitalo Ulla , Ovaskainen Marja-Leena , Niinistö Sari , Kronberg-Kippilä Carina , Marjamäki Liisa , Ahonen Suvi , Kenward Mike G , Knip Mikael , Veijola Riitta , Virtanen Suvi M
Published: August 2008

Objective

To analyse the associations of selected sociodemographic and lifestyle factors with the intake of antioxidant nutrients and consumption of their main dietary sources among pregnant women.

Design

A population-based cohort study. Dietary intake during pregnancy was assessed by a self-administered FFQ one to three months after the delivery.

Setting

Type 1 Diabetes Prediction and Prevention (DIPP) Project.

Subjects

Subjects comprised 3730 women (70·1 % of those invited) who entered the DIPP Nutrition Study after delivering a child at increased genetic risk for type 1 diabetes at the university hospitals in Oulu and Tampere, Finland, 1997–2002.

Results

All sociodemographic and lifestyle factors studied showed significant associations with antioxidant intake in multiple regression models adjusting for all other factors. Older and more educated women tended to have higher intake of most antioxidants. Parity was positively associated with retinol intake and inversely with vitamin C intake. Smokers had lower intakes of most antioxidants. Only the partner’s education was positively associated with high intake of fruits, whereas own education was positively associated with berry consumption. Vegetable consumption was positively associated with partner’s education except for women with academic education, who tended to have high vegetable consumption irrespective of partner’s education.

Conclusions

Young women, smokers and those with a low education are at risk for low antioxidant intake and non-optimal food choices during pregnancy.
Molecular medicine of microRNAs: structure, function and implications for diabetes
Authors: Hennessy Erica , O'Driscoll Lorraine
Published: August 2008

MicroRNAs (miRNAs) are a family of endogenous small noncoding RNA molecules, of 19–28 nucleotides in length. In humans, up to 3% of all genes are estimated to encode these evolutionarily conserved sequences. miRNAs are thought to control expression of thousands of target mRNAs. Mammalian miRNAs generally negatively regulate gene expression by repressing translation, possibly through effects on mRNA stability and compartmentalisation, and/or the translation process itself. An extensive range of in silico and experimental techniques have been applied to our understanding of the occurrence and functional relevance of such sequences, and antisense technologies have been successfully used to control miRNA expression in vitro and in vivo. Interestingly, miRNAs have been identified in both normal and pathological conditions, including differentiation and development, metabolism, proliferation, cell death, viral infection and cancer. Of specific relevance and excitement to the area of diabetes research, miRNA regulation has been implicated in insulin secretion from pancreatic β-cells, diabetic heart conditions and nephropathy. Further analyses of miRNAs in vitro and in vivo will, undoubtedly, enable us determine their potential to be exploited as therapeutic targets in diabetes.
Nonlinear mirror mode dynamics: Simulations and modeling
Authors: Califano F. , Hellinger P. , Kuznetsov E. , Passot T. , Sulem P. L. , Trávníček P. M.
Published: August 2008

With the aim to understand the origin of the pressure‐balanced magnetic structures in the form of holes and humps commonly observed in the solar wind and planetary magnetosheaths, high‐resolution hybrid numerical simulations of the Vlasov‐Maxwell (VM) equations using both Lagrangian (particle in cells) and Eulerian integration schemes are presented and compared with asymptotic and phenomenological models for the nonlinear mirror mode dynamics. It turns out that magnetic holes do not result from direct nonlinear saturation of the mirror instability that rather leads to magnetic humps. Nevertheless, both above and below threshold, there exist stable solutions of the VM equations in the form of large‐amplitude magnetic holes. Special attention is paid to the skewness of the magnetic fluctuations (that is negative for holes and positive for humps) and its dependency on the distance to threshold and the beta of the plasma. Furthermore, the long‐time evolution of magnetic humps resulting from the mirror instability in an extended domain far enough from threshold may, when the beta of the plasma is not too large, eventually lead to the formation of magnetic holes.
Observational estimates of entrainment and vertical salt flux in the interior of a spreading river plume
Authors: McCabe Ryan M. , Hickey Barbara M. , MacCready Parker
Published: August 2008

Observational estimates of entrainment and vertical salt flux into the tidally pulsed Columbia River plume are presented. Drifting buoys deployed in ebbing plume water downstream of the lift‐off region are used to make measurements of velocity, salinity, and horizontal divergence in the surface layer. Drifters released near the river mouth, shoreward of the propagating ocean‐plume front, catch up to the front, consistent with classical models of plume front circulation. During their offshore transit, drifter streamwise velocities decrease while salinities increase. Assuming drifter‐measured quantities are representative of plume‐averaged quantities, conservation equations evaluated between adjacent spreading drifters are used to determine the plume depth and entrainment velocity throughout the experiment. This approach provides knowledge of the mixing involved between the active lift‐off region and the offshore ocean‐plume front as the flow evolves. Because the surface drifters do not downwell at the ocean‐plume front, we do not estimate mixing in that region. We find that entrainment and vertical salt flux are largest near the river mouth, as expected, with typical values of O(10−3 m s−1) and O(10−2 practical salinity units (psu) m s−1), respectively, and that these quantities steadily decrease as the drifters move offshore. Profiles of water properties following the drifters provide knowledge of vertical stratification (0.5–4 psu m−1 at the plume base) allowing for discrete estimates of the eddy diffusivity of salt KS. Typical plume values of KS are O(10−3 m2 s−1), similar to estimates made in other plume systems and 2 orders of magnitude larger than open ocean eddy diffusivity estimates.
A numerical study on the formation of upwelling off northeast Taiwan
Authors: Wu Chau‐Ron , Lu Hung‐Fu , Chao Shenn‐Yu
Published: August 2008

We examined the spatial and temporal variations of upwelling off northeast Taiwan, using a fine‐resolution numerical model with realistic bathymetry. The zonally running shelf break in the area deflects the Kuroshio seaward and produces upwelling on its on‐shelf edge. The upwelling, in turn, manifests a cold dome or a cyclonic eddy. In depths below 150 m or so, the upwelling and hence the cyclonic eddy exist year‐round. Above this depth, the eddy waxes and wanes as the upper portion of the Kuroshio migrates seaward and shoreward, respectively. The eddy event fluctuates in a wide range of timescales. Seasonally, the occurrence heavily favors summer rather than winter, because the mean Kuroshio axis migrates seaward in summer. Intraseasonally, the fluctuation contains two dominant periods centered at 70 days and 30 days. Local wind forcing and channeling by two local canyons do not affect the eddy statistics significantly.
Application of a chemical leach technique for estimating labile particulate aluminum, iron, and manganese in the Columbia River plume and coastal waters off Oregon and Washington
Authors: Berger Carolyn J. M. , Lippiatt Sherry M. , Lawrence Michael G. , Bruland Kenneth W.
Published: August 2008

In order to determine the total concentration of bioavailable trace metals in seawater, measurement of both the dissolved and labile particulate fractions is necessary. Comparison of labile particulate metal concentrations from various researchers is limited because of differing definitions of the fraction that is potentially available to phytoplankton on a time frame of generations. A comparison experiment was conducted on coastal and riverine suspended particulate matter to determine the difference between several commonly used techniques that operationally define the labile particulate trace metal fraction. Furthermore, we compared two leach techniques for surface transect samples from within the Columbia River plume and water offshore of Oregon and Washington, United States. The particulate trace metal concentration in the leachate was determined by high‐resolution inductively coupled plasma–mass spectrometry. From this comparison, one chemical leach was chosen to best define the labile particulate fraction of Al, Fe, and Mn: a weak acid leach (25% acetic acid at pH 2) with a mild reducing agent (0.02 M hydroxylamine hydrochloride) and a short heating step (10 min 90–95°C). This leach was applied to three surface transects within the Columbia River plume. These coastal waters were found to be rich in labile particulate trace metals that are directly delivered from the Columbia River and indirectly supplied via resuspension from upwelling over a broad continental shelf.
Soil nitric oxide emissions after nitrogen and phosphorus additions in two subtropical humid forests
Authors: Li Dejun , Wang Xinming , Sheng Guoying , Mo Jiangming , Fu Jiamo
Published: August 2008

Soil nitric oxide (NO) emissions after the addition of nitrogen (N) and phosphorus (P) were studied at a broadleaf forest and a pine forest in Dinghushan Biosphere Reserve, south China. N was applied at 5 g N m−2 (or 50 kg N ha−1) and P was applied at 4 g P m−2 as NH4Cl (AN), NaNO3 (NN), NH4Cl + Na2HPO4 (AP), NaNO3 + Na2HPO4 (NP), and Na2HPO4 (P) in water solutions, respectively, in comparison with water and blank controls. Enhancement of NO emission by N addition alone was greater than that by combined addition of N and P in both forests due to the P‐limiting soil nutrient status. In both forests, temporal pattern of NO emission after adding NO3−‐N was different with that after adding NH4+‐N. NO3−‐N addition resulted in immediate NO fluxes for the broadleaf and to a lesser extent the pine forest site. In both forests, nitrification contributed more than denitrification to NO production although denitrification also played an important role in the broadleaf forest. N addition induced greater NO emission in the mature broadleaf forest than in the primary pine forest. Over the 50‐day experimental period, averaged NO fluxes in plots adding AN, NN, AP, and NP were 3.3, 2.3, 1.9, and 1.8 times that in the water control plots, respectively, for the broadleaf forest and 2.7, 1.6, 1.5, and 1.3 times that in the water control plots, respectively, for the pine forest. Applied N loss as NO‐N in AN, NN, AP, and NP plots were 2.8%, 1.6%, 1.1%, and 1.0%, respectively, in the broadleaf forest; and 2.6%, 1.0%, 0.8% and 0.4%, respectively, in the pine forest. On the average, N loss as NO from the forest floors was approximately 2% of the applied N as NH4+ or NO3− alone, quite similar to that measured by Hall and Matson (1999) from forest floors in the Hawaiian Islands.
Sensitivity of hourly Saharan dust emissions to NCEP and ECMWF modeled wind speed
Authors: Menut Laurent
Published: August 2008

The impact of atmospheric aerosol concentrations on climate remains uncertain. This is due to the lack of understanding of the physical processes involved and also to uncertainties on the data used to model them. In the case of modeled dust emissions, the key parameters are the surface wind speed and the soil characteristics. Dust emissions are issued from inhomogeneous land surfaces and depend on local changes in wind speed. Nevertheless, their representation in models is crude since the local variability of the emission is not taken into account due to the model resolution. This simplified physical representation is problematic since the first emission process, saltation, is triggered by a threshold on the wind speed value. For most model studies, the global meteorological fields used are issued either from NCEP or ECMWF models, but the impact of the forcing was never quantified. In this study, we examine the emission fluxes variability based on the selected meteorological data set. The difference between the two emission fluxes can reach a factor of 3. This bias is not systematic and is highly variable on the timescale of an hour within different areas over western Africa. The impact of the sandblasting scheme is also studied; the variation arising by using two different schemes do not exceed 20%.
Seasonal and interannual variations of Amur River discharge and their relationships to large‐scale atmospheric patterns and moisture fluxes
Authors: Tachibana Yoshihiro , Oshima Kazuhiro , Ogi Masayo
Published: August 2008

Using reanalysis data, we investigate the relationship of Amur River discharge and vertically integrated atmospheric horizontal moisture flux. The discharge has two peaks, one in May (spring) and the other in September (autumn). Comparison of the moisture flux convergence to the discharge indicates that the spring peak is supplied by the flux in previous seasons (September through April), whereas the autumn peak is supplied by the summertime flux (May through August). A northward flux associated with storm activities in the previous autumn and winter contributes to the spring discharge. The autumn discharge is mainly supplied by a northward flux associated with the Asian summer monsoon and by an eastward flux originating from evaporation in the far western inland part of Eurasia. Interannual variation in the flux and discharge is also investigated. The strong Asian summer monsoon associated with anomalous cyclonic circulation over Eurasia strengthens the summer flux convergence at an interannual time scale, resulting in anomalously large discharge in autumn. The strong Asian winter monsoon wind with a dry air mass, associated with the anomalously strong Siberian high and Aleutian low, activates evaporation. This results in anomalously large flux divergence in autumn through winter and anomalously small discharge in spring. The anomalously large spring discharge is related to the warm phase of the Arctic Oscillation. This suggests that the rapid melting of snow and frozen soil contributes to the spring discharge. These results indicate that the Asian monsoon plays an important role in the freshening of the Okhotsk Sea, in which sea ice forms with extremely low salinity.
Simulating the impact of glaciations on continental groundwater flow systems: 1. Relevant processes and model formulation
Authors: Lemieux J.‐M. , Sudicky E. A. , Peltier W. R. , Tarasov L.
Published: August 2008

In the recent literature, it has been shown that Pleistocene glaciations had a large impact on North American regional groundwater flow systems. Because of the myriad of complex processes and large spatial scales involved during periods of glaciation, numerical models have become powerful tools to examine how ice sheets control subsurface flow systems. In this paper, the key processes that must be represented in a continental‐scale 3‐D numerical model of groundwater flow during a glaciation are reviewed, including subglacial infiltration, density‐dependent (i.e., high‐salinity) groundwater flow, permafrost evolution, isostasy, sea level changes, and ice sheet loading. One‐dimensional hydromechanical coupling associated with ice loading and brine generation were included in the numerical model HydroGeoSphere and tested against newly developed exact analytical solutions to verify their implementation. Other processes such as subglacial infiltration, permafrost evolution, and isostasy were explicitly added to HydroGeoSphere. A specified flux constrained by the ice sheet thickness was found to be the most appropriate boundary condition in the subglacial environment. For the permafrost, frozen and unfrozen elements can be selected at every time step with specified hydraulic conductivities. For the isostatic adjustment, the elevations of all the grid nodes in each vertical grid column below the ice sheet are adjusted uniformly to account for the Earth's crust depression and rebound. In a companion paper, the model is applied to the Wisconsinian glaciation over the Canadian landscape in order to illustrate the concepts developed in this paper and to better understand the impact of glaciation on 3‐D continental groundwater flow systems.
Variation in bed level shear stress on surfaces sheltered by nonerodible roughness elements
Authors: Sutton Stephen L. F. , McKenna‐Neuman Cheryl
Published: August 2008

Direct bed level observations of surface shear stress, pressure gradient variability, turbulence intensity, and fluid flow patterns were carried out in the vicinity of cylindrical roughness elements mounted in a boundary layer wind tunnel. Paired corkscrew vortices shed from each of the elements result in elevated shear stress and increased potential for the initiation of particle transport within the far wake. While the size and shape of these trailing vortices change with the element spacing, they persist even for large roughness densities. Wake interference coincides with the impingement of the upwind horseshoe vortices upon one another at a point when their diameter approaches half the distance between the roughness elements. While the erosive capability of the horseshoe vortex has been suggested for a variety of settings, the present study shows that the fluid stress immediately beneath this coherent structure is actually small in comparison to that caused by compression of the incident flow as it is deflected around the element and attached vortex. Observations such as these are required for further refinement of models of stress partitioning on rough surfaces.
An investigation of site diversity and comparison with ITU‐R recommendations
Authors: Callaghan S. A. , Boyes B. , Couchman A. , Waight J. , Walden C. J. , Ventouras S.
Published: August 2008

Earth‐space radio systems operating at frequencies of 10 GHz and above are badly attenuated by rain, cloud, and atmospheric gases. As the frequencies of operational systems increase, it becomes increasingly uneconomic to compensate for the effects of fading through the use of a fixed fade margin, hence the implementation of fade mitigation techniques (FMT). The spatial and temporal variation of rain provides the justification for the use of site diversity as an FMT. Site diversity employs two or more ground stations receiving the same satellite signal with a separation distance such that the sites encounter intense rainfall at different times, and switching to the site experiencing the least fading improves system performance considerably. Measurements of the 20.7 GHz beacon carried as part of the Global Broadcast Service (GBS) payload on the U.S. Department of Defense satellite UFO‐9 have been made at three sites: two are located in the South of England (∼8 km apart), and the third receiver was located in Scotland. These beacon measurements have produced long term attenuation exceedance and site diversity gain and improvement statistics. This attenuation time series data can simulate the performance of an Earth‐space system using site diversity, indicating the optimum method of implementing this FMT. In this paper, unbalanced site diversity is investigated, as this is a more likely scenario than the balanced site diversity modeled by the ITU‐R recommendations. This paper also investigates the implementation of site diversity from a commercial context, including cost‐benefit analysis and technical feasibility.
Extreme longitudinal disturbances in the mesosphere and thermosphere observed with the Wind Imaging Interferometer on UARS
Authors: Zhang Shengpan P. , Shepherd Gordon G.
Published: August 2008

Extreme longitudinal disturbances in the O(1S) emission rate and horizontal winds in the mesosphere and thermosphere (90–180 km) are identified on three March days in 1994, 1996, and 1997 in the database of the Wind Imaging Interferometer (WINDII) on the Upper Atmosphere Research Satellite (UARS). This type of disturbance has a wave structure with apparent zonal wavenumber 1 and a very long vertical wavelength. It generates longitudinal amplitudes of 70 photons cm−3 s−1 and 120 ms−1 in the O(1S) volume emission rate and winds, respectively, and is strong enough to break the structures of migrating tides in the E‐region. In the same longitudinal zone for day and night the zonal wind driven by this disturbance has the same phase, suggesting a wave with s = −1 and a very long period, but the meridional wind has opposite phases, suggesting a standing non‐migrating diurnal tide. This super disturbance has not been observed before, and fundamental questions about it await future investigation.
Three‐dimensional seismic velocity structure of the northwestern United States
Authors: Roth Jeffrey B. , Fouch Matthew J. , James David E. , Carlson Richard W.
Published: August 2008

We present a high‐resolution, three dimensional, P‐wave tomography model for the northwestern United States. Major features of the model include clear, well‐resolved images of the Juan de Fuca–Gorda slab to depths of at least 500 km, reduced velocities beneath Newberry volcano and north‐central Oregon, increased velocities beneath the Idaho batholith, and a deep, slab‐like, eastward‐dipping feature of increased velocities beneath Nevada. We find no evidence for a mantle plume in this region, and demonstrate that suggested disruption of the Juan de Fuca slab beneath Oregon in the vicinity of Newberry volcano is an inversion artifact. We interpret the primary features of this new model within the framework of post‐Laramide tectonomagmatism and the continuing tectonic evolution of the Cascadia Subduction Zone. A model explaining the regional tectonomagmatic history consistent with the imaged seismic velocity structure is one driven by mantle flow responding to the evolving subduction system.
Polar Ultraviolet Imager observations of solar wind‐driven ULF auroral pulsations
Authors: Liou K. , Takahashi K. , Newell P. T. , Yumoto K.
Published: August 2008

Analysis of a sequence of auroral images acquired by the Polar Ultraviolet Imager (UVI) during a long‐duration (∼1.5 hr) solar wind dynamic pressure enhancement reveals auroral intensity variations in the Pc5 band. Power spectral analysis indicates that the “auroral pulsations” appeared in multiple frequency bands predominantly in the day sector and the dawn‐dusk flank of the oval, with the maximum wave power skewing toward the dawn sector. Ground‐based magnetometer recordings showed Pc5 micropulsations modulated with the auroral pulsations. The lower frequency (1–3 mHz) auroral pulsations were modulated with solar wind dynamic pressure pulses moving tailward, whereas the higher frequency (6–8 mHz) ones were not. We concluded that the lower frequency auroral pulsations were driven directly by the solar wind, whereas the higher frequency ones were associated with global compressional cavity mode. This study shows for the first time the snapshot of global Pc5 ultralow‐frequency (ULF) waves and demonstrates that global far‐ultraviolet (FUV) imaging such as Polar UVI provides a powerful ancillary tool for studying ULF waves on a global scale.
Physical and geographical origins of the South China Sea Warm Current
Authors: Chiang Tzu‐Ling , Wu Chau‐Ron , Chao Shenn‐Yu
Published: August 2008

We examine the formation mechanism of the South China Sea Warm Current in winter, using a high‐resolution, numerical model. The current, noted for its ability to flow against the prevailing northeast monsoon in winter, has received considerable attentions in recent years. The collective wisdom from previous models points to two likely generation scenarios: occasional wind relaxation or the Kuroshio intrusion. The present model consistently points to the wind relaxation as the dominant mechanism. When comparing differences between previous models and ours, we also conclude that the Kuroshio intrusion helps, but is not chiefly responsible. Tracing the current to the source, we identify the elevated sea level in the Gulf of Tonkin, induced by the northeast monsoon, as the ultimate driving force. The presence of Hainan Island bears little importance in generating the current.
Regional climate responses to geoengineering with tropical and Arctic SO2 injections
Authors: Robock Alan , Oman Luke , Stenchikov Georgiy L.
Published: August 2008

Anthropogenic stratospheric aerosol production, so as to reduce solar insolation and cool Earth, has been suggested as an emergency response to geoengineer the planet in response to global warming. While volcanic eruptions have been suggested as innocuous examples of stratospheric aerosols cooling the planet, the volcano analog actually argues against geoengineering because of ozone depletion and regional hydrologic and temperature responses. To further investigate the climate response, here we simulate the climate response to both tropical and Arctic stratospheric injection of sulfate aerosol precursors using a comprehensive atmosphere‐ocean general circulation model, the National Aeronautics and Space Administration Goddard Institute for Space Studies ModelE. We inject SO2 and the model converts it to sulfate aerosols, transports the aerosols and removes them through dry and wet deposition, and calculates the climate response to the radiative forcing from the aerosols. We conduct simulations of future climate with the Intergovernmental Panel on Climate Change A1B business‐as‐usual scenario both with and without geoengineering and compare the results. We find that if there were a way to continuously inject SO2 into the lower stratosphere, it would produce global cooling. Tropical SO2 injection would produce sustained cooling over most of the world, with more cooling over continents. Arctic SO2 injection would not just cool the Arctic. Both tropical and Arctic SO2 injection would disrupt the Asian and African summer monsoons, reducing precipitation to the food supply for billions of people. These regional climate anomalies are but one of many reasons that argue against the implementation of this kind of geoengineering.
Chondroitin sulphate‐modified neuropilin 1 is expressed in human tumour cells and modulates 3D invasion in the U87MG human glioblastoma cell line through a p130Cas‐mediated pathway
Authors: Frankel Paul , Pellet‐Many Caroline , Lehtolainen Pauliina , D'Abaco Giovanna M , Tickner Michelle L , Cheng Lili , Zachary Ian C
Published: August 2008

Neuropilin 1 (NRP1), a non‐tyrosine kinase receptor for vascular endothelial growth factor and class 3 Semaphorins, is highly expressed in many human tumour cell lines, but its function is poorly understood. Here, we describe the expression of a new chondroitin sulphate‐modified NRP1 (NRP1‐CS) in human tumour cell lines. Expression of a non‐modifiable NRP1 mutant (S612A) in U87MG human glioma cells results in enhanced invasion in three dimensions (3D), whereas wild‐type NRP1 has no effect. Furthermore, the S612A NRP1 cells show a significant increase in p130Cas tyrosine phosphorylation compared with control and wild‐type NRP1 cells. Silencing of p130Cas in S612A NRP1 cells resulted in a loss of increased invasive phenotype. Interestingly, p130Cas silencing does not inhibit basal 3D invasion, but leads to a mesenchymal to amoeboid transition. Biopsies from both low‐ and high‐grade human gliomas show strong expression of NRP1, and little expression of NRP1‐CS. Our data establish distinct roles for NRP1 and NRP1‐CS in modulating a new NRP1‐p130Cas signalling pathway contributing to glioblastoma cell invasion in 3D.
Rtt101 and Mms1 in budding yeast form a CUL4DDB1‐like ubiquitin ligase that promotes replication through damaged DNA
Authors: Zaidi Iram Waris , Rabut Gwénaël , Poveda Ana , Scheel Hartmut , Malmström Johan , Ulrich Helle , Hofmann Kay , Pasero Philippe , Peter Matthias , Luke Brian
Published: August 2008

In budding yeast the cullin Rtt101 promotes replication fork progression through natural pause sites and areas of DNA damage, but its relevant subunits and molecular mechanism remain poorly understood. Here, we show that in budding yeast Mms1 and Mms22 are functional subunits of an Rtt101‐based ubiquitin ligase that associates with the conjugating‐enzyme Cdc34. Replication forks in mms1Δ, mms22Δ and rtt101Δ cells are sensitive to collisions with drug‐induced DNA lesions, but not to transient pausing induced by nucleotide depletion. Interaction studies and sequence analysis have shown that Mms1 resembles human DDB1, suggesting that Rtt101Mms1 is the budding yeast counterpart of the mammalian CUL4DDB1 ubiquitin ligase family. Rtt101 interacts in an Mms1‐dependent manner with the putative substrate‐specific adaptors Mms22 and Crt10, the latter being a regulator of expression of ribonucleotide reductase. Taken together, our data suggest that the Rtt101Mms1 ubiquitin ligase complex might be required to reorganize replication forks that encounter DNA lesions.
TGFβ‐mediated BIM expression and apoptosis are regulated through SMAD3‐dependent expression of the MAPK phosphatase MKP2
Authors: Ramesh Sneha , Qi Xiao‐Jun , Wildey Gary M , Robinson Janet , Molkentin Jeffery , Letterio John , Howe Philip H
Published: August 2008

Transforming growth factor‐β (TGFβ) induces the expression of the pro‐apoptotic protein BIM, and mediates apoptosis in hepatocytes and B lymphocytes. BIM is regulated through a post‐translational mechanism involving ERK‐dependent phosphorylation and ubiquitin‐mediated proteasomal degradation. Here, we show that TGFβ induces BIM through its rapid inhibition of ERK, thereby preventing the phosphorylation and degradation of BIM. TGFβ, through a SMAD3‐dependent mechanism, transcriptionally induces the mitogen‐activated protein kinase (MAPK) phosphatase MKP2, encoded by an immediate early gene, to attenuate ERK and promote the accumulation of BIM protein. Overexpression of MKP2 in hepatocytes modulates ERK‐mediated phosphorylation of BIM and apoptosis in the absence of TGFβ, whereas its ablation in pro‐B cells, derived from MKP2‐deficient mice, protects cells from TGFβ‐mediated apoptosis, and blocks TGFβ‐induced ERK inhibition and BIM induction. Furthermore, in pro‐B cells derived from SMAD3‐deficient mice, induction of MKP2 by TGFβ, inhibition of ERK, induction of BIM and apoptosis do not occur. Our results indicate that MKP2 mediates TGFβ‐dependent apoptosis by linking SMAD3 to the modulation of ERK activity and mitochondrial‐mediated pro‐apoptotic events.
LabelHash: A Flexible and Extensible Method for Matching Structural Motifs
Authors: Moll Mark , Kavraki Lydia
Published: August 2008

There is an increasing number of proteins with known structure but unknown function. Determining their function would have a significant impact on understanding diseases and designing new therapeutics. Computational methods can facilitate function determination by identifying proteins that have high structural and chemical similarity. Below, we will briefly describe LabelHash, a new method for partial structure comparison. In partial structure comparison, the goal is to find the best geometric and chemical similarity between a set of 3D points called a motif and a subset of a set of 3D points called the target. Both the motif and targets are represented as sets of labeled 3D points. A motif is ideally composed of the functionally most-relevant residues in a binding site. The labels denote the type of residue. Motif points can have multiple labels to denote that substitutions are allowed. Any subset of the target that has labels that are compatible with the motif’s labels is called a match. The aim is to find statistically significant matches to a structural motif. Our method preprocesses a background database of targets such as a non-redundant subset of the Protein Data Bank in such a way that we can look up in constant time partial matches to a motif. Using a variant of the previously described match augmentation algorithm (1), we obtain complete matches to our motif. The nonparametric statistical model developed by (2,3) corrects for any bias introduced by our algorithm. This bias is introduced by excluding matches that do not satisfy certain geometric constraints for efficiency reasons.
Cerebellar Cortex, Purkinje Cell Layer
Authors:   Allen Institute for Brain Science, Wright Emily , Ng Lydia , Guillozet-Bongaarts Angela
Published: August 2008

This report contains a summary of expression patterns for genes that are enriched in the Purkinje cell layer (CBXpu) of the cerebellum. All data is derived from the Allen Brain Atlas (ABA) in situ hybridization mouse project. The structure's location and morphological characteristics in the mouse brain are described using the Nissl data found in the Allen Reference Atlas. Using an established algorithm, the expression values of the CBXpu were compared to the values of its larger parent structure, in this case the cerebellar cortex, for the purpose of extracting regionally selective gene expression data. The highest ranking genes were manually curated and verified. 50 genes were then selected and compiled for expression analysis. The experimental data for each gene may be accessed via the links provided; additional data in the sagittal plane may also be accessed using the ABA. A gene ontology table (derived from DAVID Bioinformatics Resources 2007) is also included, highlighting possible functions of the 50 genes selected for this report.
Marked difference in membrane-protein-binding properties of the two isoforms of protein 4.1R expressed at early and late stages of erythroid differentiation
Authors: Nunomura Wataru , Parra Marilyn , Hebiguchi Miwa , Sawada Ken-Ichi , Mohandas Narla , Takakuwa Yuichi
Published: August 2008

Two major isoforms of protein 4.1R, a 135 kDa isoform (4.1R135) and an 80 kDa isoform (4.1R80), are expressed at distinct stages of terminal erythroid differentiation. The 4.1R135 isoform is exclusively expressed in early erythroblasts and is not present in mature erythrocytes, whereas the 4.1R80 isoform is expressed at late stages of erythroid differentiation and is the principal component of mature erythrocytes. These two isoforms differ in that the 4.1R135 isoform includes an additional 209 amino acids designated as the HP (head-piece) at the N-terminus of 4.1R80. In the present study, we performed detailed characterization of the interactions of the two 4.1R isoforms with various membrane-binding partners and identified several isoform-specific differences. Although both 4.1R135 and 4.1R80 bound to cytoplasmic domains of GPC (glycophorin C) and band 3, there is an order of magnitude difference in the binding affinities. Furthermore, although both isoforms bound CaM (calmodulin), the binding of 4.1R80 was Ca2+-independent, whereas the binding of 4.1R135 was strongly Ca2+-dependent. The HP of 4.1R135 mediates this Ca2+-dependent binding. Ca2+-saturated CaM completely inhibited the binding of 4.1R135 to GPC, whereas it strongly reduced the affinity of its binding to band 3. Interestingly, in spite of the absence of spectrin-binding activity, the 4.1R135 isoform was able to assemble on to the membrane of early erythroblasts suggesting that its ability to bind to membrane proteins is sufficient for its membrane localization. These findings enable us to offer potential new insights into the differential contribution of 4.1R isoforms to membrane assembly during terminal erythroid differentiation.
Palladium-Catalyzed Cyanation of Aryl Perfluorooctylsulfonates
Authors: Zhu Yi-Zhong , Cai Chun
Published: August 2008

Cyanation of aryl perfluorooctylsulfonates with potassium hexacyanoferrate(ii) catalyzed by an efficient catalyst system comprising Pd(OAc)2, CuI and PPh3 or 1,1′-bis(diphenylphosphino)ferrocene (dppf) is described.