bluuebunny/crossref_metadata_2025 huggingface dataset:
The long-term consequences of partnership dissolution for support in later life in the United Kingdom
Authors: GLASER KAREN , STUCHBURY RACHEL , TOMASSINI CECILIA , ASKHAM JANET
Published: March 2008

There has long been an interest in the United Kingdom about whether and how changes in family life affect support for older people, but nevertheless the consequences of partnership dissolution for late-life support have been little researched. Using data from the British Household Panel Study (1991–2003), this study investigated the longitudinal association between partnership dissolution and two types of support for 1,966 people aged 70 or more years: (i) informal support from children in the form of contacts and help (e.g. household assistance including care), and (ii) formal support from community care services (i.e. health visitor or district nurse, home-help and meals-on-wheels). The paper also examines the level of reported support among: (i) all parents aged 70 or more years and (ii) 1,453 unpartnered parents in the same age group (i.e. those lacking the most important source of support in later life: a spouse). We found diversity in the experience of partnership dissolution in the past lives of people aged 70 or more years. Patterns of support varied by the respondent's age, whether partnered, the timing and type of partnership dissolution, and by gender, having a daughter and health status. Overall, however, partnership dissolution did not show the expected detrimental relationship with later-life support. Health needs and increasing age were strongly associated with increases in contact and informal and formal help, regardless of family history.
The prevalence of and risk factors for loneliness among older people in China
Authors: YANG KEMING , VICTOR CHRISTINA R.
Published: March 2008

Compared with the many studies in western countries, research on the prevalence of and risk factors for loneliness amongst older people in China is sparse. This paper reviews the current cross-national literature on loneliness and, using data from two national surveys undertaken in 1992 and 2000, assesses the prevalence of loneliness amongst older people in China and explores the factors that raise their vulnerability to the negative feeling. The reported prevalence of loneliness was 15.6 per cent in 1992 and 29.6 per cent in 2000. We suggest that part of the differential is accounted for by the differences in the methodologies of the two surveys and in the questions used to assess loneliness. The evidence from both surveys suggests that loneliness was relatively prevalent among those aged 65 or more years, females and those living in rural areas, and that these variations had greater amplitude in 2000. As in western countries, increased age, being widowed or divorced, and poor self-rated health were significantly associated with old-age loneliness in China at the two dates. Two factors positively related to loneliness were found that are specific to the Chinese context, however: living in a rural (as opposed to urban) area, and thinking that one's children are not filial. To develop our understanding of loneliness among older people in China and other non-western countries, it will be necessary to construct more rigorous and comparable measurements of loneliness and to undertake longitudinal studies of social relationships.
Gap junctional coupling and connexin immunoreactivity in rabbit retinal glia
Authors: ZAHS KATHLEEN R. , CEELEN PAUL W.
Published: March 2008

Gap junctions provide a pathway for the direct intercellular exchange of ions and small signaling molecules. Gap junctional coupling between retinal astrocytes and between astrocytes and Müller cells, the principal glia of vertebrate retinas, has been previously demonstrated by the intercellular transfer of gap-junction permeant tracers. However, functional gap junctions have yet to be demonstrated between mammalian Müller cells. In the present study, when the gap-junction permeant tracers Neurobiotin and Lucifer yellow were injected into a Müller cellviaa patch pipette, the tracers transferred to at least one additional cell in more than half of the cases examined. Simultaneous whole-cell recordings from pairs of Müller cells in the isolated rabbit retina revealed electrical coupling between closely neighboring cells, confirming the presence of functional gap junctions between rabbit Müller cells. The limited degree of this coupling suggests that Müller cell–Müller cell gap junctions may coordinate the functions of small ensembles of these glial cells. Immunohistochemistry and immunoblotting were used to identify the connexins in rabbit retinal glia. Connexin30 (Cx30) and connexin43 (Cx43) immunoreactivities were associated with astrocytes in the medullary ray region of the retinas of both pigmented and albino rabbits. Connexin43 was also found in Müller cells, but antibody recognition differed between astrocytic and Müller cell connexin43.
Thenob2mouse, a null mutation inCacna1f: Anatomical and functional abnormalities in the outer retina and their consequences on ganglion cell visual responses
Authors: CHANG BO , HECKENLIVELY JOHN R. , BAYLEY PHILIPPA R. , BRECHA NICHOLAS C. , DAVISSON MURIEL T. , HAWES NORM L. , HIRANO ARLENE A. , HURD RONALD E. , IKEDA AKIHIRO , JOHNSON BRITT A. , MCCALL MAUREEN A. , MORGANS CATHERINE W. , NUSINOWITZ STEVE , PEACHEY NEAL S. , RICE DENNIS S. , VESSEY KIRSTAN A. , GREGG RONALD G.
Published: March 2008

Glutamate release from photoreceptor terminals is controlled by voltage-dependent calcium channels (VDCCs). In humans, mutations in theCacna1fgene, encoding the α1Fsubunit of VDCCs, underlie the incomplete form of X-linked congenital stationary night blindness (CSNB2). These mutations impair synaptic transmission from rod and cone photoreceptors to bipolar cells. Here, we report anatomical and functional characterizations of the retina in thenob2(no b-wave 2) mouse, a naturally occurring mutant caused by a null mutation inCacna1f. Not surprisingly, theb-waves of both the light- and dark-adapted electroretinogram are abnormal innob2mice. The outer plexiform layer (OPL) is disorganized, with extension of ectopic neurites through the outer nuclear layer that originate from rod bipolar and horizontal cells, but not from hyperpolarizing bipolar cells. These ectopic neurites continue to express mGluR6, which is frequently associated with profiles that label with the presynaptic marker Ribeye, indicating potential points of ectopic synapse formation. However, the morphology of the presynaptic Ribeye-positive profiles is abnormal. While cone pedicles are present their morphology also appears compromised. Characterizations of visual responses in retinal ganglion cellsin vivo, under photopic conditions, demonstrate that ON-center cells have a reduced dynamic range, although their basic center-surround organization is retained; no alteration in the responses of OFF-center cells was evident. These results indicate thatnob2mice are a valuable model in which to explore the pathophysiological mechanisms associated withCacna1fmutations causing CSNB2, and the subsequent effects on visual information processing. Further, thenob2mouse represents a model system in which to define the signals that guide synapse formation and/or maintenance in the OPL.
Retinotopic organization of ferret suprasylvian cortex
Authors: CANTONE GINA , XIAO JUN , LEVITT JONATHAN B.
Published: March 2008

The retinotopic organization of striate and several extrastriate areas of ferret cortex has been established. Here we describe the representation of the visual field on the Suprasylvian visual area (Ssy). This cortical region runs mediolaterally along the posterior bank of the suprasylvian sulcus, and is distinct from adjoining areas in anatomical architecture. The Ssy lies immediately rostral to visual area 21, medial to lateral temporal areas, and lateral to posterior parietal areas. In electrophysiological experiments we made extracellular recordings in adult ferrets. We find that single and multiunit receptive fields range in size from 2 deg × 4 deg to 21 deg × 52 deg. The total visual field representation in Ssy spans over 70 deg in azimuth in the contralateral hemifield (with a small incursion into the ipsilateral hemifield), and from +36 deg to −30 deg in elevation. There are often two representations of the horizontal meridian. Furthermore, the location of the transition from upper to lower fields varies among animals. General features of topography are confirmed in anatomical experiments in which we made tracer injections into different locations in Ssy, and determined the location of retrograde label in area 17. Both isoelevation and isoazimuth lines can span substantial rostrocaudal and mediolateral distances in cortex, sometimes forming closed contours. This topography results in cortical magnifications averaging 0.07 mm/deg in elevation and 0.06 mm/deg in azimuth; however, some contours can run in such a way that it is possible to move a large distance on cortex without moving in the visual field. Because of these irregularities, Ssy contains a coarse representation of the contralateral visual field.
Ionotropic glutamate receptors of amacrine cells of the mouse retina
Authors: DUMITRESCU OLIVIA N. , PROTTI DARIO A. , MAJUMDAR SRIPARNA , ZEILHOFER HANNS ULRICH , WÄSSLE HEINZ
Published: March 2008

The mammalian retina contains approximately 30 different morphological types of amacrine cells, receiving glutamatergic input from bipolar cells. In this study, we combined electrophysiological and pharmacological techniques in order to study the glutamate receptors expressed by different types of amacrine cells. Whole-cell currents were recorded from amacrine cells in vertical slices of the mouse retina. During the recordings the cells were filled with Lucifer Yellow/Neurobiotin allowing classification as wide-field or narrow-field amacrine cells. Amacrine cell recordings were also carried out in a transgenic mouse line whose glycinergic amacrine cells express enhanced green fluorescent protein (EGFP). Agonist-induced currents were elicited by exogenous application of NMDA, AMPA, and kainate (KA) while holding cells at −75 mV. Using a variety of specific agonists and antagonists (NBQX, AP5, cyclothiazide, GYKI 52466, GYKI 53655, SYM 2081) responses mediated by AMPA, KA, and NMDA receptors could be dissected. All cells (n= 300) showed prominent responses to non-NMDA agonists. Some cells expressed AMPA receptors exclusively and some cells expressed KA receptors exclusively. In the majority of cells both receptor types could be identified. NMDA receptors were observed in about 75% of the wide-field amacrine cells and in less than half of the narrow-field amacrine cells. Our results confirm that different amacrine cell types express distinct sets of ionotropic glutamate receptors, which may be critical in conferring their unique temporal responses to this diverse neuronal class.
Lichenicolous fungi described from Antarctica and the sub-Antarctic islands by Carroll W. Dodge (1895–1988)
Authors: Hawksworth David L. , Iturriaga Teresa
Published: March 2008

The identities of the 12 lichenicolous fungi described as new to science from the Antarctic and sub-Antarctic islands by Carroll W. Dodge between 1938 and 1968 are reassessed on the basis of the original publications, and where extant the original collections and slides in the Farlow Herbarium and Reference Library (Harvard University, Cambridge, MA, USA). Typifications are discussed and lectotypes and neotypes designated as necessary. Only one species is accepted in its original placement (Phacopsis usneae) and one had already been transferred to an appropriate genus (Didymella cladoniae to Zwackhiomyces). Six prove to be synonyms of previously described species, and four are combined into other genera here: Arthonia parmeliae (syn. Diplonaevia parmeliae), Carbonea antarctica (syn. Alectoria antarctica), Sphaerellothecium buelliae (syn. Orbicula buelliae), and Weddelomyces gasparriniae (syn. Phaeospora gasparriniae) combs. nov. The generic name Thelidiola is also confirmed as a synonym of Muellerella. In addition, as a result of earlier misinterpretations of Dodge’s taxa, two new species are described: Endococcus matzeri, and Zwachkiomyces diederichii spp. nov. Intralichen lichenum is also reported from the Antarctic for the first time. Descriptions and illustrations are included where appropriate.
Determinants of terrestrial arthropod community composition at Cape Hallett, Antarctica
Authors: Sinclair Brent J. , Scott Matthew B. , Klok C. Jaco , Terblanche John S. , Marshall David J. , Reyers Belinda , Chown Steven L.
Published: March 2008

The distribution and abundance of free-living arthropods from soil and under stones were surveyed at the Cape Hallett ice-free area (ASPA No. 106), North Victoria Land, Antarctica. A total of 327 samples from 67 plots yielded 11 species of arthropods comprised of three Collembola: Cryptopygus cisantarcticus, Friesea grisea and Isotoma klovstadi and eight mites: Coccorhagidia gressitti, Eupodes wisei, Maudheimia petronia, Nanorchestes sp., Stereotydeus belli, S. punctatus, Tydeus setsukoae and T. wadei. Arthropods were absent from areas occupied by the large Adélie penguin colony. There was some distinction among arthropod communities of different habitats, with water and a lichen species (indicative of scree slope habitats) ranking as significant community predictors alongside spatial variables in a Canonical Correspondence Analysis. Recent changes to the management plan for ASPA No. 106 may need to be revisited as the recommended campsite is close to the area of greatest arthropod diversity.
Temperature observations in Antarctic tafoni: implications for weathering, biological colonization, and tafoni formation
Authors: Hall Kevin , André Marie-Françoise
Published: March 2008

Tafoni have long been recognized, measured and discussed within the Antarctic context. However, with respect to the formative processes tafoni still remain somewhat of an enigma. In terms of the weathering attributes of tafoni, one problem is the monitoring of environmental conditions without the transducers themselves altering that environment. The application of ultra-small thermocouples provides an avenue for monitoring of rock surface temperatures without influence on the tafoni environment. At an Antarctic site temperatures were measured both inside and outside of a tafone, with data at 20 second intervals. These data show a spatial variability that may help explain tafoni development, at least in terms of weathering. Humidity data indicate that moisture conditions are very low such that water-based weathering processes are temporally and spatially constrained. The presence of several episodes of extreme temperature variations indicates that thermal stress may be an important contributor to weathering here. It is argued that the absence of any endolithic communities (at this site) within the sandstone, in which the tafoni develop, is a reflection of weathering rates that exceed the ability of organisms to invade and colonize the rock. At the present time, weathering appears to be primarily in the form of granular disintegration and flaking.
The Cape Purvis volcano, Dundee Island (northern Antarctic Peninsula): late Pleistocene age, eruptive processes and implications for a glacial palaeoenvironment
Authors: Smellie J.L. , Mcintosh W.C. , Esser R. , Fretwell P.
Published: March 2008

Cape Purvis is a conspicuous promontory on southern Dundee Island. It forms a prominent mesa that contrasts with the smooth, shield-like (snow-covered) topography of the remainder of the island. The promontory is composed of fresh alkaline basaltic (hawaiite) volcanic rocks compositionally similar to younger lavas on Paulet Island 5 km to the east. The outcrop is one of the youngest and northernmost satellite centres of the James Ross Island Volcanic Group. 40Ar/39Ar isotopic dating indicates that the Cape Purvis volcano is 132 ± 19 ka in age. The examined sequence probably formed as a lava-fed delta during a subglacial eruption late in the glacial period corresponding to Isotope Stage 6, when the ice sheet surface elevation was 300–400 m higher than at present. A remarkable unidirectional age progression is now evident, from volcanic centres in Prince Gustav Channel (c. 2.0–1.6 Ma), through Tabarin Peninsula (1.69–c. 1 Ma) to Cape Purvis and Paulet islands (132–few ka). The age variations are tentatively ascribed to construction of progressively younger volcanic centres at the leading edge of an easterly-opening deep fault system, although the origins of the postulated fault system are unclear.
Quantifying low rates of summertime sublimation for buried glacier ice in Beacon Valley, Antarctica
Authors: Kowalewski D.E. , Marchant D.R , Levy J.S. , Head J.W.
Published: March 2008

A remnant of Taylor Glacier ice rests beneath a 40–80 cm thick layer of sublimation till in central Beacon Valley, Antarctica. A vapour diffusion model was developed to track summertime vapour flow within this till. As input, we used meteorological data from installed HOBO data loggers that captured changes in solar radiance, atmospheric temperature, relative humidity, soil temperature, and soil moisture from 18 November 2004–29 December 2004. Model results show that vapour flows into and out of the sublimation till at rates dependent on the non-linear variation of soil temperature with depth. Although measured meteorological conditions during the study interval favoured a net loss of buried glacier ice (∼0.017 mm), we show that ice preservation is extremely sensitive to minor perturbations in temperature and relative humidity. Net loss of buried glacier ice is reduced to zero (during summer months) if air temperature (measured 2 cm above the till surface) decreases by 5.5°C (from −7°C to −12°C); or average relative humidity increases by 22% (from ∼36% to 58%); or infiltration of minor snowmelt equals ∼0.002 mm day−1. Our model results are consistent with the potential for long-term survival of buried glacier ice in the hyper-arid stable upland zone of the western Dry Valleys.
KATRINA: Unmasking Race, Poverty, and Politics in the 21stCentury
Authors: Bobo Lawrence D.
Published: March 2008

In his allegorical tale “Racism's Secret Bonding,” legal scholar Derrick Bell imagined the occurrence of fourth of July “racial data storms.” During these storms, the consciousness of each and every White American was flooded with full information about the slave trade, slavery, lynching, Jim Crow, and contemporary discrimination, as well as a powerful emotional appreciation for the human suffering entailed by these conditions. Bell's “racial data storms” created great turmoil, anxiety, and demands for action. These demands focused on preventing future waves of “racial data storms” but also sought significant progressive policy intervention against discrimination and inequality. Bell mused that by the time the “racial data storms” had stopped, they “left behind them the greatest social reform movement America had ever known” (1992, p. 150).
“THE STORM DIDN'T DISCRIMINATE”: Katrina and the Politics of Color Blindness
Authors: Lieberman Robert C.
Published: March 2008

Hurricane Katrina exposed the politics of race, poverty, and inequality to broad public view for the first time in a generation. But the storm and its aftermath also constituted a metaphor for the deep tension between color-blind and race-conscious models of politics that has long been one of the central and defining themes of U.S. politics. In this essay, I explore Hurricane Katrina as a window onto this fundamental dualism in U.S. political culture, its ambivalent embrace of both color blindness and race consciousness. In the storm's immediate aftermath, President George W. Bush became the unlikely mouthpiece of this dualism, and I examine his contradictory statements about race in the storm's wake and place them in historical context. I connect these presidential statements to the broader political context that shapes race policymaking in order to ask whether Katrina and the political response it provoked might generate a policy response that takes seriously the problem of racial inequality exposed by the storm. A brief account of a parallel historical example of race-conscious policy emerging from political conditions apparently dominated by color blindness, the emergence of affirmative action in employment in the 1960s and 1970s, emphasizes the mixture of ideological and strategic, political factors that shape U.S. race politics and policy, and suggests a set of ideological and institutional conditions that may be necessary to generate such a dramatic change in policy direction. I conclude by drawing some lessons from this history for post-Katrina race politics.
HURRICANE KATRINA AND NEW ORLEANIANS' SENSE OF PLACE: Return
and Reconstitution or “Gone with the Wind”?
Authors: Falk William W. , Hunt Matthew O. , Hunt Larry L.
Published: March 2008

This paper explores some implications of Hurricane Katrina, especially
as it affected, and will continue to affect, African Americans. Our
observations stem largely from our ongoing examination of the demography
of African Americans, including motivations to leave the South
historically, and recent changes generating a significant “return
migration” of African Americans to the South. The specific case of
Katrina-related migration requires examining issues of race and
class—including the destinations to which Katrina's victims
were displaced and key features of the place to which they might return.
We leave for others the evaluation of ongoing political debates concerning
responsibility for who did what, and why. Our focus is on New Orleans as a
place, and what prospects exist for reconstituting that place in light of
past, present, and prospective demographic trends. We first review recent
work on place and identity, and describe the general features of past
migration patterns of African Americans—both from the South and back
to the South. We then identify important features of New Orleans as a
distinctive place on the U.S. landscape, in part by comparing New Orleans
with other southern cities using the 1% Integrated Public Use Microdata
Series (IPUMS) sample of 2000 U.S. Census data. Finally, we assess the
prospects of the reconstitution of New Orleans as a place resembling what
it was prior to Katrina, by examining the intersecting factors of race,
class, and ethnicity in shaping how, and by whom, the city may be
resettled. We project that the city will be smaller, more White and
Hispanic, more affluent, and more tourism/ entertainment-oriented than
its pre-Katrina reality. Given the difficulty of making such projections,
we conclude with an analysis of various demographic portraits of what the
racial composition of New Orleans may become, depending on (1) its future
size, and (2) relative rates of return migration by White and Black New
Orleanians.
DEVA-STATING DISASTERS: Race in the Shadow(s) of New Orleans
Authors: Goldberg David Theo
Published: March 2008

Neoconservative lobbyist Grover Norquist has declared that he wishes
so to diminish government in the U.S. that he can drown it in a bathtub.
This paper will address the ways in which Katrina has laid bare how the
neoconservative attack on the state since the early 1980s, and especially
in the past five years, has (1) targeted for devastation those public
agencies supportive of the racially defined poor, thus rendering them far
more vulnerable to disasters, both natural and social; and (2) shifted
state resources away from poorer, especially African American and Latino,
citizens to the interests of wealthier (and overwhelmingly White)
Americans, in effect privatizing the definition and implementation of
public programs in the name of “charitable contributions”.
This trend has also had the effect of shifting racial discriminations from
the public to the private realm, thus making racism less visible and more
difficult to address, while at the same time easier to deny in
practice.
UNEARTHING IGNORANCE: Hurricane Katrina and the Re-Envisioning of the Urban Black Poor
Authors: Young Alford A.
Published: March 2008

This essay explores some social ramifications of two portraits of low-income African American New Orleanians that proliferated throughout the country since the arrival of Hurricane Katrina on the Gulf Coast. The dissemination of these portraits reveals much about America's cultural understandings of African Americans and urban poverty. Some recent ethnographic and qualitative-methodological work has striven to create new depictions of this constituency, but a divide persists between general-public readings of the African American urban poor and those of liberal-minded field researchers who have studied this population. This essay concludes with some reflection on issues concerning the potential for this research to bridge the divide, given the power of mainstream media outlets to construct and promote certain images of disadvantaged and disenfranchised social groups relative to the social power of academic scholarship to achieve the same end.
Aspiration and outflow of the intermediate water in the East/Japan Sea through the Tsugaru Strait
Authors: Park Jong Jin , Kim Kuh , Yang Joon‐Yong
Published: March 2008

Outflow of the intermediate water in the East/Japan Sea through the Tsugaru Strait is inferred from the fact that profiling floats deployed below the sill depth in the central East/Japan Sea moved out to the Northwest Pacific Ocean through the Strait. Careful analysis of the float trajectories reveals that profiling floats parked at 350m, 700m, and 800m could be uplifted from depths below the sill of the Tsugaru Strait and moved over the 140m deep sill with a probability close to 100%. Application of an analytical model for the Bernoulli suction shows that intermediate waters can be aspirated over the sill depth of the Tsugaru Strait in late winter.
Modeling GPS phase multipath with SNR: Case study from the Salar de Uyuni, Boliva
Authors: Bilich Andria , Larson Kristine M. , Axelrad Penina
Published: March 2008

Multipath, wherein a signal arrives at the receiving antenna by more than one path, is a significant and largely unmodeled source of GPS positioning error. We present a technique for mitigating specular multipath in GPS carrier phase measurements using the signal‐to‐noise ratio (SNR), in which the frequency and amplitude content of non‐stationary oscillations in SNR are modeled to extract multipath parameters (direct and reflected signal amplitudes, and the phase difference between direct and indirect signals). The frequency content of SNR data is estimated using wavelet analysis, then used to initialize an adaptive least squares process to solve for time‐varying multipath parameters. Multipath corrections derived from these parameters are applied to the phase observables. We demonstrate this technique using campaign GPS data collected over a large salt flat (Salar de Uyuni), specifically a tripod‐mounted station which experienced long‐period (300–2000 s) multipath oscillations in SNR from ground reflections. By contrasting position solutions before and after applying multipath corrections, we demonstrate a reduction in carrier phase postfit residual RMS of up to 20% for static positioning, and 1–7 dB reduction in spectral power at multipath periods for kinematic positions.
Combination of laser and radar altimeter height measurements to estimate snow depth during the 2004 Antarctic AMSR‐E Sea Ice field campaign
Authors: Leuschen Carlton J. , Swift Robert N. , Comiso Josefino C. , Raney R. Keith , Chapman Rickey D. , Krabill William B. , Sonntag John G.
Published: March 2008

Among the most important parameters needed to evaluate the present and future state of Antarctic sea ice cover is the ice thickness. The retrieval of ice thickness using remote sensing techniques has been hampered by the absence of a capability to remotely measure snow thickness covering the sea ice. Data sets collected with Johns Hopkins Applied Physics Laboratory's Delay‐Doppler Phase Monopulse (D2P) radar and NASA's Airborne Topographic Mapper (ATM) scanning lidar during NASA's Antarctic AMSR‐E Sea Ice field campaign over the Bellingshausen Sea are used to demonstrate the potential of a remote‐sensing technique for retrieval of snow cover thickness from an airborne platform. The technique takes advantage of the fact that the radar is most sensitive to the snow‐ice interface while the lidar responds to the highly optically reflective snow surface. The difference between the radar‐ and laser‐determined surfaces yields an estimate of snow thickness that appears to be reasonably consistent with expected values. The technique requires careful registration of the instrument footprints. Because there was no absolute range calibration of the lidar due to predeployment scheduling difficulties, the vertical offset between the instruments was resolved by determining the difference between measurements over leads. Elsewhere over sea ice the radar‐defined surface is generally below the laser‐defined surface consistent with the radar defining the snow‐ice interface. Over a relatively small portion of the data, we observed opposite relationship between the sensor‐defined surfaces for which we discuss a plausible physical explanation.
Characteristics of the atmospheric CO2 signal as observed over the conterminous United States during INTEX‐NA
Authors: Choi Yonghoon , Vay Stephanie A. , Vadrevu Krishna P. , Soja Amber J. , Woo Jung‐Hun , Nolf Scott R. , Sachse Glen W. , Diskin Glenn S. , Blake Donald R. , Blake Nicola J. , Singh Hanwant B. , Avery Melody A. , Fried Alan , Pfister Leonhard , Fuelberg Henry E.
Published: March 2008

High resolution in situ measurements of atmospheric CO2 were made from the NASA DC‐8 aircraft during the Intercontinental Chemical Transport Experiment–North America (INTEX‐NA) campaign, part of the wider International Consortium for Atmospheric Research on Transport and Transformation (ICARTT). During the summer of 2004, eighteen flights comprising 160 h of measurements were conducted within a region bounded by 27 to 53°N and 36 to 139°W over an altitude range of 0.15 to 12 km. These large‐scale surveys provided the opportunity to examine the characteristics of the atmospheric CO2 signal over sparsely sampled areas of North America and adjacent ocean basins. The observations showed a high degree of variability (≤18%) due to the myriad source and sink processes influencing the air masses intercepted over the INTEX‐NA sampling domain. Surface fluxes had strong effects on continental scale concentration gradients. Clear signatures of CO2 uptake were seen east of the Mississippi River, notably a persistent CO2 deficit in the lowest 2–3 km. When combining the airborne CO2 measurements with LANDSAT and MODIS data products, the lowest CO2 mixing ratios observed during the campaign (337 ppm) were tied to mid‐continental agricultural fields planted in corn and soybeans. We used simultaneous measurements of CO, O3, C2Cl4, C2H6, C2H2 and other unique chemical tracers to differentiate air mass types. Coupling these distinct air mass chemical signatures with transport history permitted identification of convection, stratosphere‐troposphere exchange, long‐range transport from Eastern Asia, boreal wildfires, and continental outflow as competing processes at multiple scales influencing the observed concentrations. Our results suggest these are important factors contributing to the large‐scale distribution in CO2 mixing ratios thus these observations offer new constraints in the computation of the North American carbon budget.
Study of long‐term trend in aerosol optical thickness observed from operational AVHRR satellite instrument
Authors: Zhao Tom X.‐P. , Laszlo Istvan , Guo Wei , Heidinger Andrew , Cao Changyong , Jelenak Aleksandar , Tarpley Dan , Sullivan Jerry
Published: March 2008

The long‐term trend of aerosol optical thickness (AOT) over the global oceans has been studied by using a nearly 25‐year aerosol record from the Advanced Very High Resolution Radiometer (AVHRR) Pathfinder Atmosphere extended (PATMOS‐x) data set. Both global and regional analyses have been performed to derive the AOT tendencies for monthly, seasonal, and annual mean AOT values at AVHRR 0.63 μm channel (or Channel‐1). A linear decadal change of −0.01 is obtained for globally and monthly averaged aerosol optical thickness, τ1, of AVHRR Channel‐1. This negative tendency is even more evident for globally and annually averaged τ1 and the magnitude can be up to −0.03/decade. Seasonal patterns in the AOT regional long‐term trend are evident. In general, negative tendencies are observed for seasonally averaged τ1 in regions influenced by emissions from industrialized countries and the magnitude can be up to −0.10/decade. Positive tendencies are observed in regions influenced by emissions from fast developing countries and the magnitude can be up to +0.04/decade. For regions heavily influenced by Saharan desert particles, a negative trend with a maximum magnitude of −0.03/decade is detected. However, over regions influenced by smoke from biomass burning, positive tendencies with a maximum magnitude of +0.04/decade are observed. Sensitivity analyses have also been performed to study the effects of radiance calibration, aerosol retrieval algorithm, and spatial resolution of input retrieval radiances on the global aerosol long‐term tendencies.
Impact of Peroxisome Proliferator–activated Receptors γ and δ on Adiposity in Toddlers and Preschoolers in the GENESIS Study
Authors: Lagou Vasiliki , Scott Robert A. , Manios Yannis , Chen Tun‐Li Joshua , Wang Guan , Grammatikaki Evangelia , Kortsalioudaki Christine , Liarigkovinos Thodoris , Moschonis George , Roma‐Giannikou Eleftheria , Pitsiladis Yannis P.
Published: March 2008

Peroxisome proliferator–activated receptor γ (PPAR γ) and peroxisome proliferator–activated receptor δ (PPAR δ) are promising candidate genes for obesity. Associations between adiposity‐related phenotypes and genetic variation in PPAR γ (Pro12Ala and C1431T), as well as PPAR δ (T+294C) were assessed in 2,102 Greek children aged 1–6 years, as part of a large‐scale epidemiological study (Growth, Exercise and Nutrition Epidemiological Study In preSchoolers). In girls aged 3–4 years, the Ala12 allele was associated with higher mid‐upper arm (P = 0.010) and hip (P = 0.005) circumferences, as well as subscapular (P = 0.008) and total skinfolds (P = 0.011) that explained 2.0, 3.7, 2.1, and 1.9% of the phenotypic variance, respectively, while the T1431 allele was associated with higher mean values for waist circumference (P = 0.018) and suprailiac skinfold (P = 0.017), genotype accounting for 1.6% of the variance in both phenotypes. No significant effects of PPAR δ T+294C polymorphism or the interaction of the PPAR δ and PPAR γ variants on adiposity‐related phenotypes were observed in any age group or gender. Haplotype‐based analysis including both PPAR γ polymorphisms revealed that in girls aged 3–4 years, the Ala‐T haplotype was associated with higher waist (P = 0.014) and hip (P = 0.007) circumferences compared to the common Pro‐C haplotype. The PPAR γ Pro12Ala and C1431T polymorphisms are associated with increased adiposity during early childhood in a gender‐ and age‐specific manner and independently of the PPAR δ T+294C polymorphism.
Psychometric Evaluation of the Eating Disorder Examination‐Questionnaire for Bariatric Surgery Candidates
Authors: Hrabosky Joshua I. , White Marney A. , Masheb Robin M. , Rothschild Bruce S. , Burke‐Martindale Carolyn H. , Grilo Carlos M.
Published: March 2008

Objective: Despite increasing use of the Eating Disorder Examination‐Questionnaire (EDE‐Q) in bariatric surgery patients, little is known about the utility and psychometric performance of this self‐report measure in this clinical group. The primary purpose of the current study was to evaluate the factor structure and construct validity of the EDE‐Q in a large series of bariatric surgery candidates.

Methods and Procedures: Participants were 337 obese bariatric surgery candidates. Participants completed the EDE‐Q and a battery of behavioral and psychological measures.

Results: Exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) produced a 12‐item, 4‐factor structure of the EDE‐Q. The four factors, interpreted as Dietary Restraint, Eating Disturbance, Appearance Concerns, and Shape/Weight Overvaluation, were found to be internally consistent and converged with other relevant measures of psychopathology.

Discussion: Factor analysis of the EDE‐Q in bariatric surgery candidates did not replicate the original subscales but revealed an alternative factor structure. Future research must further evaluate the psychometric properties, including the factor structure, of the EDE‐Q in this and other diverse populations and consider means of improving this measure's ability to best assess eating‐related pathology in bariatric surgery patients.
Energy Gain and Energy Gap in Normal‐weight Children: Longitudinal Data of the KOPS
Authors: Plachta‐Danielzik Sandra , Landsberg Beate , Bosy‐Westphal Anja , Johannsen Maike , Lange Dominique , Müller Manfred J.
Published: March 2008

Population‐based prevention of overweight needs evidence‐based goals consistent with our present knowledge about energy gap (i.e., daily imbalance between energy intake and energy expenditure resulting in overweight). Longitudinal data of normal‐weight children (1,029 girls and 1,028 boys; Kiel Obesity Prevention Study, KOPS) were used to calculate energy gain (i.e., increase in fat mass (FM) and fat‐free mass (FFM)) in normal‐weight children staying normal weight (persistent children) or becoming overweight (incident children). Taking into account weight gain in proportion to height gain (normal development) energy gap was calculated from increases in FM and FFM exceeding normal development. Children were divided into two groups and were followed from age 6 to 10 (group A) and 10 to 14 years (group B). FM and FFM were measured. Medians of 4‐year BMI‐ (kg/m2)/weight changes (kg) were +1.8/+13.2 (A) and +3.0/+18.7 (B) in girls, and +1.6/+12.8 (A) and +2.6/21.7 (B) in boys. Corresponding data for FM/FFM (kg) were +3.1/+10.2 (A) and +5.1/12.7 (B) in girls, and +2.3/10.8 (A) and +3.0/18.6 (B) in boys. The 4‐year‐incidence of overweight (%) were 9.4 (A) and 5.4 (B) in girls, and 11.0 (A) and 3.8 (B) in boys, respectively. Mean energy gains (kcal/day) were 26.8 (A) and 46.4 (B) in girls, and 22.1 (A) and 32.5 (B) in boys. The 90th percentile of energy gap (kcal/day) in incident children were 58.1 (A) and 72.0 (B) in girls and 46.0 (A) and 53.2 (B) in boys. To prevent overweight in children energy gap should not exceed 46–72 kcal/day.
Biochemical and structural analysis of α-catenin in cell–cell contacts
Authors: Pokutta Sabine , Drees Frauke , Yamada Soichiro , Nelson W. James , Weis William I.
Published: March 2008

Cadherins are transmembrane adhesion molecules that mediate homotypic cell–cell contact. In adherens junctions, the cytoplasmic domain of cadherins is functionally linked to the actin cytoskeleton through a series of proteins known as catenins. E-cadherin binds to β-catenin, which in turn binds to α-catenin to form a ternary complex. α-Catenin also binds to actin, and it was assumed previously that α-catenin links the cadherin–catenin complex to actin. However, biochemical, structural and live-cell imaging studies of the cadherin–catenin complex and its interaction with actin show that binding of β-catenin to α-catenin prevents the latter from binding to actin. Biochemical and structural data indicate that α-catenin acts as an allosteric protein whose conformation and activity changes depending on whether or not it is bound to β-catenin. Initial contacts between cells occur on dynamic lamellipodia formed by polymerization of branched actin networks, a process controlled by the Arp2/3 (actin-related protein 2/3) complex. α-Catenin can suppress the activity of Arp2/3 by competing for actin filaments. These findings lead to a model for adherens junction formation in which clustering of the cadherin–β-catenin complex recruits high levels of α-catenin that can suppress the Arp2/3 complex, leading to cessation of lamellipodial movement and formation of a stable contact. Thus α-catenin appears to play a central role in cell–cell contact formation.
Structural studies on desmosomes
Authors: Al-Amoudi Ashraf , Frangakis Achilleas S.
Published: March 2008

Desmosomes are cadherin-based intercellular junctions that primarily provide mechanical stability to tissues such as epithelia and cardiac muscle. Desmosomal cadherins, which are Ca2+-dependent adhesion molecules, are of central importance in mediating direct intercellular interaction. The close association of these proteins, with intracellular components of desmosomes ultimately linked to the cytoskeleton, is believed to play an important role in tissue morphogenesis during development and wound healing. Elucidation of the binding mechanism of adhesive interfaces between the extracellular domains of cadherins has been approached by structural, biophysical and biochemical methods. X-ray crystal structures of isolated extracellular domains of cadherins have provided compelling evidence of the mutual binding of the highly conserved N-terminal residue, Trp2, from opposing proteins. This binding interface was also implicated by biochemical and cell-adhesion assays and mutagenesis data to be the primary adhesive interface between cells. Recent results based on electron tomography of epidermal desmosomes were consistent with this view, showing cadherin molecules interacting at their N-terminal tips. An integrative structural approach involving X-ray crystallography, cryo-electron tomography and immuno-electron microscopy should give the complete picture of the architecture of this important junction; identifying its various proteins and showing their arrangements and binding interfaces under native conditions. Together with these ‘static’ approaches, live-cell imaging of cultured keratinocytes should provide important insights into the dynamic property of the assembly and disassembly of desmosomes.
Integrin connections to the cytoskeleton through talin and vinculin
Authors: Ziegler Wolfgang H. , Gingras Alex R. , Critchley David R. , Emsley Jonas
Published: March 2008

Integrins are αβ heterodimeric receptors that mediate attachment of cells to the extracellular matrix and therefore play important roles in cell adhesion, migration, proliferation and survival. Among the cytoskeletal proteins that interact directly with the β-chain cytoplasmic domain, talin has emerged as playing a critical role in integrin activation and linkage to the actin cytoskeleton. Talin (2541 amino acids) is an elongated (60 nm) flexible antiparallel dimer, with a small globular head connected to an extended rod. The talin head contains a FERM (4.1/ezrin/radixin/moesin) domain (residues 86–400) with binding sites for several β integrin cytodomains and the talin rod contains a second lower-affinity integrin-binding site, a highly conserved C-terminal actin-binding site and also several binding sites for vinculin. We have determined previously the crystal structures of two domains from the talin rod, spanning residues 482–789. Talin-(482–655), which contains a VBS (vinculin-binding site), folds into a five-helix bundle whereas talin-(656–789) is a four-helix bundle. We have also reported the crystal structure of the N-terminal vinculin head domain in complex with an activated form of talin. In the present paper, we consider how binding sites buried within the folded helical bundles of talin and α-actinin form interactions with vinculin.
Cell–collagen interactions: the use of peptide Toolkits to investigate collagen–receptor interactions
Authors: Farndale Richard W. , Lisman Ton , Bihan Dominique , Hamaia Samir , Smerling Christiane S. , Pugh Nicholas , Konitsiotis Antonios , Leitinger Birgit , de Groot Philip G. , Jarvis Gavin E. , Raynal Nicolas
Published: March 2008

Fibrillar collagens provide the most fundamental platform in the vertebrate organism for the attachment of cells and matrix molecules. We have identified specific sites in collagens to which cells can attach, either directly or through protein intermediaries. Using Toolkits of triple-helical peptides, each peptide comprising 27 residues of collagen primary sequence and overlapping with its neighbours by nine amino acids, we have mapped the binding of receptors and other proteins on to collagens II or III. Integrin α2β1 binds to several GXX′GER motifs within the collagens, the affinities of which differ sufficiently to control cell adhesion and migration independently of the cellular regulation of the integrin. The platelet receptor, Gp (glycoprotein) VI binds well to GPO (where O is hydroxyproline)-containing model peptides, but to very few Toolkit peptides, suggesting that sequence in addition to GPO triplets is important in defining GpVI binding. The Toolkits have been applied to the plasma protein vWF (von Willebrand factor), which binds to only a single sequence, identified by truncation and amino acid substitution within Toolkit peptides, as GXRGQOGVMGFO in collagens II and III. Intriguingly, the receptor tyrosine kinase, DDR2 (discoidin domain receptor 2) recognizes three sites in collagen II, including its vWF-binding site, although the amino acids that support the interaction differ slightly within this motif. Furthermore, the secreted protein BM-40 (basement membrane protein 40) also binds well to this same region. Thus the availability of extracellular collagen-binding proteins may be important in regulating and facilitating direct collagen–receptor interaction.
Theoretical investigation of the magnetic and magneto-optical properties of neodymium trifluoride under high magnetic field
Authors: Zhang Fang , Xu You , Guillot Maurice , Yang Jie Hui
Published: March 2008

Based on the quantum theory, a detailed theoretical analysis of both the magnetic and magneto-optical properties of NdF3 is developed. Using the one-ion model, the choice of the crystal field parameters plays a crucial role. The reasons for the 4.2K isothermal M(H) curve intersecting with the 1.6K M(H) curve, and for the nonlinear relation between the Faraday rotation and the magnetic field at low temperature, are that the lowest three crystal fields and spin-orbit interaction split levels are not only split, but also strongly mixed with each other by H. Other specific properties like the magnetic susceptibility anisotropy in the 4.2–1100K temperature range are also well interpreted.
Graded photonic crystals curve the flow of light: An experimental demonstration by the mirage effect
Authors: Akmansoy Eric , Centeno Emmanuel , Vynck Kevin , Cassagne David , Lourtioz Jean-Michel
Published: March 2008

We report the experimental demonstration of a beam curvature in graded photonic crystals via a spectacular mirage effect. A two-dimensional structure of metallic rods is constructed to produce this effect in the microwave domain near 10GHz. Experimental results are in excellent agreement with theoretical predictions, thus, proving the versatility of graded photonic crystals in view of their integration in future photonic circuits.
Quantitative analysis of electronic transport through weakly coupled metal/organic interfaces
Authors: Molinari A. S. , Gutiérrez Lezama I. , Parisse P. , Takenobu T. , Iwasa Y. , Morpurgo A. F.
Published: March 2008

Using single-crystal transistors, we have performed a systematic experimental study of electronic transport through oxidized copper/rubrene interfaces as a function of temperature and bias. We find that the measurements can be quantitatively reproduced in terms of the thermionic emission theory for Schottky diodes, if the effect of the bias-induced barrier lowering is included. Our analysis emphasizes the role of the coupling between metal and molecules, which in our devices is weak due to the presence of an oxide layer at the surface of the copper electrodes.