bluuebunny/crossref_metadata_2025 huggingface dataset:
Rain versus Snow in the Sierra Nevada, California: Comparing Doppler Profiling Radar and Surface Observations of Melting Level
Authors: Lundquist Jessica D. , Neiman Paul J. , Martner Brooks , White Allen B. , Gottas Daniel J. , Ralph F. Martin
Published: April 2008

The maritime mountain ranges of western North America span a wide range of elevations and are extremely sensitive to flooding from warm winter storms, primarily because rain falls at higher elevations and over a much greater fraction of a basin’s contributing area than during a typical storm. Accurate predictions of this rain–snow line are crucial to hydrologic forecasting. This study examines how remotely sensed atmospheric snow levels measured upstream of a mountain range (specifically, the bright band measured above radar wind profilers) can be used to accurately portray the altitude of the surface transition from snow to rain along the mountain’s windward slopes, focusing on measurements in the Sierra Nevada, California, from 2001 to 2005. Snow accumulation varies with respect to surface temperature, diurnal cycles in solar radiation, and fluctuations in the free-tropospheric melting level. At 1.5°C, 50% of precipitation events fall as rain and 50% as snow, and on average, 50% of measured precipitation contributes to increases in snow water equivalent (SWE). Between 2.5° and 3°C, snow is equally likely to melt or accumulate, with most cases resulting in no change to SWE. Qualitatively, brightband heights (BBHs) detected by 915-MHz profiling radars up to 300 km away from the American River study basin agree well with surface melting patterns. Quantitatively, this agreement can be improved by adjusting the melting elevation based on the spatial location of the profiler relative to the basin: BBHs decrease with increasing latitude and decreasing distance to the windward slope of the Sierra Nevada. Because of diurnal heating and cooling by radiation at the mountain surface, BBHs should also be adjusted to higher surface elevations near midday and lower elevations near midnight.
Thailand Daily Rainfall and Comparison with TRMM Products
Authors: Chokngamwong Roongroj , Chiu Long S.
Published: April 2008

Daily rainfall data collected from more than 100 gauges over Thailand for the period 1993–2002 are used to study the climatology and spatial and temporal characteristics of Thailand rainfall variations. Comparison of the Thailand gauge (TG) data binned at 1° × 1° with the Global Precipitation Climatology Centre (GPCC) monitoring product shows a small bias (1.11%), and the differences can be reconciled in terms of the increased number of stations in the TG dataset. Comparison of daily TG with Tropical Rainfall Measuring Mission (TRMM) version 6 (V6) 3B42 rain estimates shows improvements over version 5 (V5) in terms of bias and mean absolute difference (MAD). The V5 is computed from the adjusted Geostationary Operational Environmental Satellite (GOES) precipitation index (AGPI) and V6 is computed using the TRMM Multisatellite Precipitation Analysis (TMPA) algorithm. The V6 histogram is much closer to that of TG than V5 in terms of rain fraction and conditional rain rates. Scatterplots show that both versions of the satellite products are deficient in capturing heavy rain events. In terms of detecting rain events, a critical success index (CSI) shows no difference between V6 and V5 3B42. The CSI for V6 is higher for the rainy season than the dry season. These results are generally insensitive to rain-rate threshold and averaging periods. The temporal and spatial autocorrelation of daily rain rates for TG, V6, and V5 3B42 are computed. Autocorrelation function analyses show improved temporal and spatial autocorrelations for V6 compared to TG over V5 with e-folding times of 1, 1, and 2 days, and isotropic spatial decorrelation distances of 1.14°, 1.87°, and 3.61° for TG, V6, and V5, respectively. Rain event statistics show that the V6 3B42 overestimates the rain event durations and underestimates the rain event separations and the event conditional rain rates when compared to TG. This study points to the need to further improve the 3B42 algorithm to lower the false detection rate and improve the estimation of heavy rainfall events.
Spatial Estimation of Reference Evapotranspiration in Andalusia, Spain
Authors: Vanderlinden Karl , Giráldez Juan Vicente , Van Meirvenne Marc
Published: April 2008

Knowledge of the spatial and temporal distribution of reference crop evapotranspiration (ET0) is of interest for regional water resources management, especially in areas of the world where fine-tuning of agricultural water demands over large areas is required. This study provides a strategy for mapping ET0 in regions with low meteorological data availability. For Andalusia, Spain, it involves estimating ET0 from temperature data using a locally calibrated version of the Hargreaves equation and the application of geostatistical interpolation techniques that take into account elevation as secondary information. Average annual ET0 at 191 observatories (with elevation between 0 and 1260 m) ranged from 954 to 1460 mm, with an average of 1283 mm, a standard deviation of 99 mm, and a correlation coefficient with elevation of −0.86. Simple kriging with varying local means (SKlm) and kriging with an external drift (KED)—two methods that take into account elevation as secondary information—increased spatial model efficiency by 30% as compared to ordinary kriging. SKlm was used for mapping ET0 since it better reproduced the descriptive statistics of the point data and yielded slightly smaller root-mean-squared estimation errors than KED. The spatial correlation of annual and monthly ET0 was well structured and anisotropic. Short-range variability, for separation distances up to 20–40 km, showed a strong linear increase with distance while long-range variability, up to 130–250 km, increased more gently with distance. The results of this structural analysis are relevant for the spatial optimization of a recently installed automated ET0 observation network, while obtained maps constitute a valuable tool for regional water resources evaluation, planning, and management and contribute to optimizing water use in local irrigated agriculture.
Stommel’s Box Model of Thermohaline Circulation Revisited—The Role of Mechanical Energy Supporting Mixing and the Wind-Driven Gyration
Authors: Guan Yu Ping , Huang Rui Xin
Published: April 2008

The classical two-box model of Stommel is extended in two directions: replacing the buoyancy constraint with an energy constraint and including the wind-driven gyre. Stommel postulated a buoyancy constraint for the thermohaline circulation, and his basic idea has evolved into the dominating theory of thermohaline circulation; however, recently, it is argued that the thermohaline circulation is maintained by mechanical energy from wind stress and tides. The major difference between these two types of models is the bifurcation structure: the Stommel-like model has two thermal modes (one stable and another one unstable) and one stable haline mode, whereas the energy-constraint model has one stable thermal mode and two saline modes (one stable and another one unstable). Adding the wind-driven gyre changes the threshold value of thermohaline bifurcation greatly; thus, the inclusion of the wind-driven gyre is a vital step in completely modeling the physical processes related to thermohaline circulation.
Subtidal Salinity and Velocity in the Hudson River Estuary: Observations and Modeling
Authors: Ralston David K. , Geyer W. Rockwell , Lerczak James A.
Published: April 2008

A tidally and cross-sectionally averaged model based on the temporal evolution of the quasi-steady Hansen and Rattray equations is applied to simulate the salinity distribution and vertical exchange flow along the Hudson River estuary. The model achieves high skill at hindcasting salinity and residual velocity variation during a 110-day period in 2004 covering a wide range of river discharges and tidal forcing. The approach is based on an existing model framework that has been modified to improve model skill relative to observations. The external forcing has been modified to capture meteorological time-scale variability in salinity, stratification, and residual velocity due to sea level fluctuations at the open boundary and along-estuary wind stress. To reflect changes in vertical mixing due to stratification, the vertical mixing coefficients have been modified to use the bottom boundary layer height rather than the water depth as an effective mixing length scale. The boundary layer parameterization depends on the tidal amplitude and the local baroclinic pressure gradient through the longitudinal Richardson number, and improves the model response to spring–neap variability in tidal amplitude during periods of high river discharge. Finally, steady-state model solutions are evaluated for both the Hudson River and northern San Francisco Bay over a range of forcing conditions. Agreement between the model and scaling of equilibrium salinity intrusions lends confidence that the approach is transferable to other estuaries, despite significant differences in bathymetry. Discrepancies between the model results and observations at high river discharge are indicative of limits at which the formulation begins to fail, and where an alternative approach that captures two-layer dynamics would be more appropriate.
Interannual Variability and Trends of Extratropical Ozone. Part I: Northern Hemisphere
Authors: Jiang Xun , Pawson Steven , Camp Charles D. , Nielsen J. Eric , Shia Run-Lie , Liao Ting , Limpasuvan Varavut , Yung Yuk L.
Published: April 2008

The authors apply principal component analysis (PCA) to the extratropical total column ozone from the combined merged ozone data product and the European Centre for Medium-Range Weather Forecasts assimilated ozone from January 1979 to August 2002. The interannual variability (IAV) of extratropical O3 in the Northern Hemisphere (NH) is characterized by four main modes. Attributable to dominant dynamical effects, these four modes account for nearly 60% of the total ozone variance in the NH. The patterns of variability are distinctly different from those derived for total O3 in the tropics. To relate the derived patterns of O3 to atmospheric dynamics, similar decompositions are performed for the 30–100-hPa geopotential thickness. The results reveal intimate connections between the IAV of total ozone and the atmospheric circulation.

The first two leading modes are nearly zonally symmetric and represent the connections to the annular modes and the quasi-biennial oscillation. The other two modes exhibit in-quadrature, wavenumber-1 structures that, when combined, describe the displacement of the polar vortices in response to planetary waves. In the NH, the extrema of these combined modes have preferred locations that suggest fixed topographical and land–sea thermal forcing of the involved planetary waves. Similar spatial patterns and trends in extratropical column ozone are simulated by the Goddard Earth Observation System chemistry–climate model (GEOS-CCM).

The decreasing O3 trend is captured in the first mode. The largest trend occurs at the North Pole, with values ∼−1 Dobson Unit (DU) yr−1. There is almost no trend in tropical O3. The trends derived from PCA are confirmed using a completely independent method, empirical mode decomposition, for zonally averaged O3 data. The O3 trend is also captured by mode 1 in the GEOS-CCM, but the decrease is substantially larger than that in the real atmosphere.
Interannual Variability and Trends of Extratropical Ozone. Part II: Southern Hemisphere
Authors: Jiang Xun , Pawson Steven , Camp Charles D. , Nielsen J. Eric , Shia Run-Lie , Liao Ting , Limpasuvan Varavut , Yung Yuk L.
Published: April 2008

A principal component analysis (PCA) is applied to the Southern Hemisphere (SH) total column ozone following the method established for analyzing the data in the Northern Hemisphere (NH) in a companion paper. The interannual variability (IAV) of extratropical O3 in the SH is characterized by four main modes, which account for 75% of the total variance. The first two leading modes are approximately zonally symmetric and relate to the Southern Hemisphere annular mode and the quasi-biennial oscillation. The third and fourth modes exhibit wavenumber-1 structures. Contrary to the Northern Hemisphere, the third and fourth modes are not related to stationary waves. Similar results are obtained for the 30–100-hPa geopotential thickness. The decreasing O3 trend in the SH is captured in the first mode. The largest trend is at the South Pole, with value ∼−2 Dobson Units (DU) yr−1. Both the spatial pattern and trends in the column ozone are captured by the Goddard Earth Observation System chemistry–climate model (GEOS-CCM) in the SH.
Supervision of Psychotherapy
Authors: Westefeld John S.
Published: April 2008

Current models and issues related to psychotherapy supervision are examined. These include ethical and legal issues, problems of interpersonal competence, and multicultural issues. As a part of this analysis, interviews about supervision with five prominent counseling psychologists are included to provide their perspectives. Implications for the field of counseling psychology are described, and a series of recommendations is presented.
The Racialized Picket Line: White Workers and Racism in the Southern California Supermarket Strike
Authors: Wilson Jake B.
Published: April 2008

In a time when union membership is increasingly becoming more racially and ethnically diverse, it is important to understand how race impacts the strategies of contemporary labor struggles. This study explores the racial consciousness of white union members participating in the UFCW grocery workers' strike in Southern California. Using data gathered through in-depth interviews and participant observation, I document the gender-specific racialization of `scabs' and customers as expressed by white union members through a series of in-depth interviews and participant observation. This study uncovers the myriad ways white supremacy and white racial solidarity are created and maintained in a multiracial labor struggle.
Using the LCP: Bereaved Relatives' Assessments of Communication and Bereavement
Authors: Veerbeek Laetitia , van der Heide Agnes , de Vogel-Voogt Elsbeth , de Bakker René , D. van der Rijt Carin C. , Swart Siebe J. , van der Maas Paul J. , van Zuylen Lia
Published: April 2008

The Liverpool Care Pathway (LCP) is aimed at improving care and communication in the dying phase. The authors studied whether use of the LCP affects relatives' retrospective evaluation of communication and their level of bereavement. An intervention study was conducted. During the baseline period, usual care was provided to dying patients. During the intervention period, the LCP was used for 79% of the patients. In total, bereaved relatives filled in a questionnaire for 57% of the patients, on average 4 months after death. In the intervention period, relatives had lower bereavement levels when compared with relatives in the baseline period ( P = .01). Communication was evaluated similarly for both periods. We conclude that LCP use during the dying phase seems to moderately contribute to lower levels of bereavement in relatives.
Visual abstraction and anatomy: pre- and post-modern imagery
Authors: Daly Tricia , Bell Philip
Published: April 2008

Illustrations from pre-modern and Renaissance `Anatomies', on the one hand, and late 20th-century digital representations of male and female anatomy, on the other, are contrasted and compared in terms of social semiotic concepts. The title page of On the Fabric of the Human Body (1543), for instance, presents detailed narrativizations and conceptual constructions of the changing worlds and significance of public anatomical demonstrations and their settings in `theatres'. In the early anatomical illustrations discussed, women's bodies were objectified as the locus of male surgeons' practices, revealing the truth of bifurcated gender. Similarly, in popular digital sequences of anatomy composed around mobile microphotographic `fly-throughs' in The Human Body (1998) and in other Wellcome Trust/BBC productions, gender is abstracted in ways that continue to naturalize long-established binaries.
Ethnicity and the Hebrew Bible: Problems and Prospects
Authors: Miller James C.
Published: April 2008

This article examines recent studies of ethnicity in the Hebrew Bible. A subsequent article will analyze similar studies of the New Testament writings. After a brief overview of selected trends in the study of ethnic identity, I organize my analysis according to broad historical periods in the biblical narrative: pre-monarchic, monarchic, and exilic/postexilic eras with monographs receiving the bulk of attention. I conclude that three persistent problems hinder progress in these investigations. First, the inability of scholars to agree upon dates for biblical texts, our best source for ascertaining ethnicity, limits our capacity to locate them within specific socio-historical contexts and thereby reconstruct Israel's ethnic identity at a given time and place. Second, the evidence that can be dated most accurately, archaeological remains, provides inadequate data for drawing conclusions about ethnic self-perceptions. Finally, vague definitions of ethnicity result in imprecise characterizations of Israel's identity. Such methodological and theoretical difficulties are not unique to this young sub-discipline of Hebrew Bible studies, nor should they detract from the fact that analysis of ethnic dynamics in the Hebrew Bible is a promising development in the overall study of ancient Israelite identity.
A novel representation of RNA secondary structure based on element-contact graphs
Authors: Shu Wenjie , Bo Xiaochen , Zheng Zhiqiang , Wang Shengqi
Published: April 2008

Background

Depending on their specific structures, noncoding RNAs (ncRNAs) play important roles in many biological processes. Interest in developing new topological indices based on RNA graphs has been revived in recent years, as such indices can be used to compare, identify and classify RNAs. Although the topological indices presented before characterize the main topological features of RNA secondary structures, information on RNA structural details is ignored to some degree. Therefore, it is necessity to identify topological features with low degeneracy based on complete and fine-grained RNA graphical representations.

Results

In this study, we present a complete and fine scheme for RNA graph representation as a new basis for constructing RNA topological indices. We propose a combination of three vertex-weighted element-contact graphs (ECGs) to describe the RNA element details and their adjacent patterns in RNA secondary structure. Both the stem and loop topologies are encoded completely in the ECGs. The relationship among the three typical topological index families defined by their ECGs and RNA secondary structures was investigated from a dataset of 6,305 ncRNAs. The applicability of topological indices is illustrated by three application case studies. Based on the applied small dataset, we find that the topological indices can distinguish true pre-miRNAs from pseudo pre-miRNAs with about 96% accuracy, and can cluster known types of ncRNAs with about 98% accuracy, respectively.

Conclusion

The results indicate that the topological indices can characterize the details of RNA structures and may have a potential role in identifying and classifying ncRNAs. Moreover, these indices may lead to a new approach for discovering novel ncRNAs. However, further research is needed to fully resolve the challenging problem of predicting and classifying noncoding RNAs.
Exploiting and integrating rich features for biological literature classification
Authors: Wang Hongning , Huang Minlie , Ding Shilin , Zhu Xiaoyan
Published: April 2008

Background

Efficient features play an important role in automated text classification, which definitely facilitates the access of large-scale data. In the bioscience field, biological structures and terminologies are described by a large number of features; domain dependent features would significantly improve the classification performance. How to effectively select and integrate different types of features to improve the biological literature classification performance is the major issue studied in this paper.

Results

To efficiently classify the biological literatures, we propose a novel feature value schema TF*ML, features covering from lower level domain independent “string feature” to higher level domain dependent “semantic template feature”, and proper integrations among the features. Compared to our previous approaches, the performance is improved in terms of AUC and F-Score by 11.5% and 8.8% respectively, and outperforms the best performance achieved in BioCreAtIvE 2006.

Conclusions

Different types of features possess different discriminative capabilities in literature classification; proper integration of domain independent and dependent features would significantly improve the performance and overcome the over-fitting on data distribution.
Autosomal mutations affecting Y chromosome loops in Drosophila melanogaster
Authors: Ceprani Francesca , Raffa Grazia D , Petrucci Romano , Piergentili Roberto
Published: April 2008

Background

The Y chromosome of Drosophila melanogaster harbors several genes required for male fertility. The genes for these fertility factors are very large in size and contain conspicuous amounts of repetitive DNA and transposons. Three of these loci (ks-1, kl-3 and kl-5) have the ability to develop giant lampbrush-like loops in primary spermatocytes, a cytological manifestation of their active state in these cells. Y-loops bind a number of non-Y encoded proteins, but the mechanisms regulating their development and their specific functions are still to be elucidated.

Results

Here we report the results of a screen of 726 male sterile lines to identify novel autosomal genes controlling Y-loop function. We analyzed mutant testis preparations both in vivo and by immunofluorescence using antibodies directed against Y-loop-associated proteins. This screen enabled us to isolate 17 mutations at 15 loci whose wild-type function is required for proper Y-loop morphogenesis. Six of these loci are likely to specifically control loop development, while the others display pleiotropic effects on both loops and meiotic processes such as spermiogenesis, sperm development and maturation. We also determined the map position of the mutations affecting exclusively Y-loop morphology.

Conclusion

Our cytological screening permitted us to identify novel genetic functions required for male spermatogenesis, some of which show pleiotropic effects. Analysis of these mutations also shows that loop development can be uncoupled from meiosis progression. These data represent a useful framework for the characterization of Y-loop development at a molecular level and for the study of the genetic control of heterochromatin.
Gene expression analyses in maize inbreds and hybrids with varying levels of heterosis
Authors: Stupar Robert M , Gardiner Jack M , Oldre Aaron G , Haun William J , Chandler Vicki L , Springer Nathan M
Published: April 2008

Background

Heterosis is the superior performance of F1hybrid progeny relative to the parental phenotypes. Maize exhibits heterosis for a wide range of traits, however the magnitude of heterosis is highly variable depending on the choice of parents and the trait(s) measured. We have used expression profiling to determine whether the level, or types, of non-additive gene expression vary in maize hybrids with different levels of genetic diversity or heterosis.

Results

We observed that the distributions of better parent heterosis among a series of 25 maize hybrids generally do not exhibit significant correlations between different traits. Expression profiling analyses for six of these hybrids, chosen to represent diversity in genotypes and heterosis responses, revealed a correlation between genetic diversity and transcriptional variation. The majority of differentially expressed genes in each of the six different hybrids exhibited additive expression patterns, and ~25% exhibited statistically significant non-additive expression profiles. Among the non-additive profiles, ~80% exhibited hybrid expression levels between the parental levels, ~20% exhibited hybrid expression levels at the parental levels and ~1% exhibited hybrid levels outside the parental range.

Conclusion

We have found that maize inbred genetic diversity is correlated with transcriptional variation. However, sampling of seedling tissues indicated that the frequencies of additive and non-additive expression patterns are very similar across a range of hybrid lines. These findings suggest that heterosis is probably not a consequence of higher levels of additive or non-additive expression, but may be related to transcriptional variation between parents. The lack of correlation between better parent heterosis levels for different traits suggests that transcriptional diversity at specific sets of genes may influence heterosis for different traits.
ERCC1 and BRCA1 mRNA expression levels in metastatic malignant effusions is associated with chemosensitivity to cisplatin and/or docetaxel
Authors: Wang Lifeng , Wei Jia , Qian Xiaoping , Yin Haitao , Zhao Yang , Yu Lixia , Wang Tingting , Liu Baorui
Published: April 2008

Background

One of the major challenges in currently chemotherapeutic theme is lacking effective biomarkers for drug response and sensitivity. Our current study focus on two promising biomarkers, ERCC1 (excision repair cross-complementing group 1) and BRCA1 (breast cancer susceptibility gene 1). To investigate their potential role in serving as biomarkers for drug sensitivity in cancer patients with metastases, we statistically measure the mRNA expression level of ERCC1 and BRCA1 in tumor cells isolated from malignant effusions and correlate them with cisplatin and/or docetaxel chemosensitivity.

Methods

Real-time quantitative PCR is used to analysis related genes expression in forty-six malignant effusions prospectively collected from non-small cell lung cancer (NSCLC), gastric and gynecology cancer patients. Viable tumor cells obtained from malignant effusions are tested for their sensitivity to cisplatin and docetaxel using ATP-TCA assay.

Results

ERCC1 expression level is negatively correlated with the sensitivity to cisplatin in NSCLC patients (P = 0.001). In NSCLC and gastric group, BRCA1 expression level is negatively correlated with the sensitivity to cisplatin (NSCLC: P = 0.014; gastric: P = 0.002) while positively correlated with sensitivity to docetaxel (NSCLC: P = 0.008; gastric: P = 0.032). A significant interaction is found between ERCC1 and BRCA1 mRNA expressions on sensitivity to cisplatin (P = 0.010, n = 45).

Conclusion

Our results demonstrate that ERCC1 and BRCA1 mRNA expression levels are correlated with in vitro chemosensitivity to cisplatin and/or docetaxel in malignant effusions of NSCLC and gastric cancer patients. And combination of ERCC1 and BRCA1 may have a better role on predicting the sensitivity to cisplatin than the single one is considered.
A cohort study of infant feeding practices in city, suburban and rural areas in Zhejiang Province, PR China
Authors: Qiu Liqian , Zhao Yun , Binns Colin W , Lee Andy H , Xie Xing
Published: April 2008

Background

Breastfeeding is the basis for appropriate nutrition for infants and is strongly supported by the Ministry of Health in China. However, there are differences in infant feeding practices in different areas of the country. The aim of this study was to compare the infant feeding practices and the prevalence of determinants of initiation and continuing to breastfeed until six months of age in city, suburb and rural areas in Zhejiang Province, PRC.

Methods

A longitudinal cohort study of infant feeding practices was undertaken in city, suburban and rural areas in 2004/2005. Mothers were recruited and interviewed before discharge from hospitals. A total of 1520 mothers were recruited into the study. Follow-up interviews were administered at 1, 3 and 6 months after birth to obtain details of infant feeding practices.

Results

'Any breastfeeding' rates were high before discharge at all three locations, 96.5% in city, 96.8% in suburb and 97.4% in the rural area. The 'exclusive breastfeeding' rates in the city, suburban and rural areas before discharge were 38.0%, 63.4% and 61.0% respectively. By sixth months the 'any breastfeeding' rates had declined to 62.8%, 76.9% and 83.6% and the 'exclusive breastfeeding' rates had fallen to 0.2%, 0.5% and 7.2% in city, suburb and rural areas respectively. There were differences in feeding practices between the three locations, including the use of prelacteal feeds and the introduction of supplementary feeds.

Conclusion

Mothers who lived in the city were least likely to be 'exclusive breastfeeding' at discharge. At six months the city infants also had lower rates of 'any breastfeeding' and 'exclusive breastfeeding'.
Strengthening the virtual-source method for time-lapse monitoring
Authors: Mehta Kurang , Sheiman Jon L. , Snieder Roel , Calvert Rodney
Published: April 2008

Time-lapse monitoring is a powerful tool for tracking subsurface changes resulting from fluid migration. Conventional time-lapse monitoring can be done by observing differences between two seismic surveys over the surveillance period. Along with the changes in the subsurface, differences in the two seismic surveys are also caused by variations in the near-surface overburden and acquisition discrepancies. The virtual-source method monitors below the time-varying near-surface by redatuming the data down to the subsurface receiver locations. It crosscorrelates the signal that results from surface shooting recorded by subsurface receivers placed below the near-surface. For the Mars field data, redatuming the recorded response down to the permanently placed ocean-bottom cable (OBC) receivers using the virtual-source method allows one to reconstruct a survey as if virtualsources were buried at the OBC receiver locations and the medium above them were a homogeneous half-space. Separating the recorded wavefields into upgoing and downgoing (up-down) waves before crosscorrelation makes the resultant virtual-source data independent of the time-varying near-surface (seawater). For time-lapse monitoring, varying source signature for the two surveys and for each shot is also undesirable. Deconvolving the prestack crosscorrelated data (correlation gather) by the power spectrum of the source-time function results in virtual-source data independent of the source signature. Incorporating up-down wavefield separation and deconvolution of the correlation gather by the source power spectrum into the virtual-source method suppresses the causes of nonrepeatability in the seawater along with acquisition and source signature discrepancies. This processing combination strengthens the virtual-source method for time-lapse monitoring.
Signal Transducer and Activator of Transcription-3 Is Required in Hypothalamic Agouti-Related Protein/Neuropeptide Y Neurons for Normal Energy Homeostasis
Authors: Gong Lijie , Yao Fayi , Hockman Kristin , Heng Henry H. , Morton Gregory J. , Takeda Kiyoshi , Akira Shizuo , Low Malcolm J. , Rubinstein Marcelo , MacKenzie Robert G.
Published: April 2008

Signal transducer and activator of transcription (Stat)-3 signals mediate many of the metabolic effects of the fat cell-derived hormone, leptin. In mice, brain-specific depletion of either the long form of the leptin receptor (Lepr) or Stat3 results in comparable obese phenotypes as does replacement of Lepr with an altered leptin receptor locus that codes for a Lepr unable to interact with Stat3. Among the multiple brain regions containing leptin-sensitive Stat3 sites, cells expressing feeding-related neuropeptides in the arcuate nucleus of the hypothalamus have received much of the focus. To determine the contribution to energy homeostasis of Stat3 expressed in agouti-related protein (Agrp)/neuropeptide Y (Npy) arcuate neurons, Stat3 was deleted specifically from these cells, and several metabolic indices were measured. It was found that deletion of Stat3 from Agrp/Npy neurons resulted in modest weight gain that was accounted for by increased adiposity. Agrp/Stat3-deficient mice also showed hyperleptinemia, and high-fat diet-induced hyperinsulinemia. Stat3 deletion in Agrp/Npy neurons also resulted in altered hypothalamic gene expression indicated by increased Npy mRNA and decreased induction of suppressor of cytokine signaling-3 in response to leptin. Agrp mRNA levels in the fed or fasted state were unaffected. Behaviorally, mice without Stat3 in Agrp/Npy neurons were mildly hyperphagic and hyporesponsive to leptin. We conclude that Stat3 in Agrp/Npy neurons is required for normal energy homeostasis, but Stat3 signaling in other brain areas also contributes to the regulation of energy homeostasis.
Distinct Modes of Activation of Phosphatidylinositol 3-Kinase in Response to Cyclic Adenosine 3′, 5′-Monophosphate or Insulin-Like Growth Factor I Play Different Roles in Regulation of Cyclin D1 and p27Kip1 in FRTL-5 Cells
Authors: Fukushima Toshiaki , Nedachi Taku , Akizawa Hidenori , Akahori Masakazu , Hakuno Fumihiko , Takahashi Shin-Ichiro
Published: April 2008

Bioactivities of IGFs in various cells are often potentiated in the presence of other hormones. In previous studies we showed that pretreatment of rat FRTL-5 thyroid cells with TSH or other cAMP-generating agents markedly potentiated DNA synthesis induced by IGF-I. Under these conditions we found that phosphatidylinositol (PI) 3-kinase was activated in response to either cAMP or IGF stimulus, and both activation modes were indispensable for the potentiation of DNA synthesis. The present studies were undertaken to elucidate how cAMP and/or IGF-I stimulus regulated the G1 cyclin-cyclin dependent kinase (CDK)-inhibitor system, and to determine the roles of PI 3-kinase activation by cAMP or IGF-I stimulus in this system. We found that cAMP pretreatment enhanced IGF-I-dependent increases in cyclin D1, due to synergistic increases in mRNA and elevation of translation rates. Furthermore, cAMP pretreatment enhanced IGF-I-induced protein degradation of the CDK inhibitor, p27Kip1. These changes well explained an increase in cyclin E, leading to marked activation of G1 CDKs, followed by retinoblastoma protein phosphorylation. Our results using a PI 3-kinase inhibitor showed that cAMP-dependent PI 3-kinase activation plays an important role in the increase in cyclin D1 translation. In contrast, IGF-I-dependent PI 3-kinase activation was required for the increase in cyclin D1 mRNA levels and degradation of p27Kip1. Together, the present study elucidates the role of cAMP and IGF-I in differentially activating PI 3-kinase as a mediator of multiple molecular events. These events converge in the regulation of cyclin D1 and p27Kip1, leading to cAMP-dependent potentiation of IGF-I-dependent CDK activation and DNA synthesis.
Diurnal Amplitudes of Arterial Pressure and Heart Rate Are Dampened in Clock Mutant Mice and Adrenalectomized Mice
Authors: Sei Hiroyoshi , Oishi Katsutaka , Chikahisa Sachiko , Kitaoka Kazuyoshi , Takeda Eiji , Ishida Norio
Published: April 2008

Arterial pressure (AP), heart rate (HR), and cardiovascular diseases, including ischemic heart attack and cerebrovascular accident, show diurnal variation. Evidence that circadian-related genes contribute to cardiovascular control has been accumulated. In this study, we measured the AP and HR of Clock mutant mice on the Jcl/ICR background to determine the role of the Clock gene in cardiovascular function. Mice with mutated Clock genes had a dampened diurnal rhythm of AP and HR, compared with wild-type control mice, and this difference disappeared after adrenalectomy. The diurnal acrophase in both mean arterial pressure and HR was delayed significantly in Clock mutant mice, compared with wild-type mice, and this difference remained after adrenalectomy. Clock mutant mice had a lower concentration of plasma aldosterone, compared with wild-type mice. Our data suggest that the adrenal gland is involved in the diurnal amplitude, but not the acrophase, of AP and HR, and that the function of the Clock gene may be related to the nondipping type of AP elevation.
Neonatal Gonadectomy and Adult Testosterone Replacement Suggest an Involvement of Limbic Arginine Vasopressin and Androgen Receptors in the Organization of the Hypothalamic-Pituitary-Adrenal Axis
Authors: Bingham Brenda , Viau Victor
Published: April 2008

Testosterone exposure during critical periods of development exerts major organizing effects on the hypothalamic-pituitary-adrenal (HPA) axis. Here we examined how neonatal gonadectomy (GDX) with or without testosterone treatment during the first week of life alters the HPA response to adult testosterone replacement in 65-d-old male rats. As adults, neonatal GDX rats showed higher levels of plasma corticosterone and Fos activation in medial parvocellular part of the paraventricular nucleus of the hypothalamus under basal conditions and during 30 min of restraint exposure. These responses were normalized with testosterone treatment on postnatal d 1–5 but were not restored with adult testosterone replacement. As adults, neonatal GDX rats also showed a decrease in the number of androgen receptor and arginine vasopressin-positive cells in the bed nucleus of the stria terminalis and in the medial nucleus of the amygdala, and both of these responses were reversed with postnatal testosterone treatment. In stressed and unstressed animals, the number of androgen receptors and arginine vasopressin-expressing neurons in both of these nuclei correlated negatively with corticosterone concentrations in plasma and Fos levels in the paraventricular nucleus. Taken together, our findings suggest that testosterone exposure during the neonatal period primes the adult HPA response to testosterone by altering androgen receptor levels and function within afferent mediators of basal and stress-related input to the HPA axis.
Starvation and Triglycerides Reverse the Obesity-Induced Impairment of Insulin Transport at the Blood-Brain Barrier
Authors: Urayama Akihiko , Banks William A.
Published: April 2008

Insulin in the brain acts as a satiety factor, reduces appetite, and decreases body mass. Altered sensing by brain of insulin may be a leading cause of weight gain and insulin resistance. A decrease in the transport across the blood-brain barrier (BBB) of insulin may induce brain insulin resistance by inducing obesity. We here report that transport of iv administrated insulin across the BBB of obese mice, as measured by multiple-time regression analysis, was significantly lower than that in thin adult mice. The reduction in obese mice was reversed by starvation for 48 h. There were no differences in insulin transport rates across the BBB of obese, thin, or starved obese mice when studied by the brain perfusion model, demonstrating that BBB transport of insulin is modulated by circulating factors. In the brain perfusion study, the triglyceride triolein significantly increased the brain uptake of insulin, an effect opposite to that on leptin transport, in starved obese mice. Thus, circulating triglycerides are one of the systemic modulators for the transport of insulin across the BBB.
Dendritic Action Potential Initiation in Hypothalamic Gonadotropin-Releasing Hormone Neurons
Authors: Roberts Carson B. , Campbell Rebecca E. , Herbison Allan E. , Suter Kelly J.
Published: April 2008

It is dogma that action potentials are initiated at the soma/axon hillock of neurons. However, dendrites often exhibit conductances necessary for spike generation and represent functionally independent processing compartments within neurons. GnRH neurons provide an interesting neuronal phenotype with simple, relatively unbranched, unipolar or bipolar dendrites of extensive lengths (>1000 μm) covered in spines. These neurons control fertility and must integrate a variety of internal homeostatic and external environmental cues. We used imaging, electrophysiological, and modeling studies to understand how they integrate and process information along dendrites. Simultaneous recordings from distal dendrites and somata of individual GnRH neurons indicate distal dendrites are the primary site of spike initiation in these cells. Compartmental modeling indicates that sites of spike initiation depend upon location of excitatory input and dendrite geometry. Together, these studies demonstrate a novel pattern of spike generation in mammalian neurons and indicate that afferent inputs within distal dendritic microdomains directly initiate action potentials.
Dietary Curcumin Significantly Improves Obesity-Associated Inflammation and Diabetes in Mouse Models of Diabesity
Authors: Weisberg Stuart P. , Leibel Rudolph , Tortoriello Drew V.
Published: April 2008

Obesity is a major risk factor for the development of type 2 diabetes, and both conditions are now recognized to possess significant inflammatory components underlying their pathophysiologies. We tested the hypothesis that the plant polyphenolic compound curcumin, which is known to exert potent antiinflammatory and antioxidant effects, would ameliorate diabetes and inflammation in murine models of insulin-resistant obesity. We found that dietary curcumin admixture ameliorated diabetes in high-fat diet-induced obese and leptin-deficient ob/ob male C57BL/6J mice as determined by glucose and insulin tolerance testing and hemoglobin A1c percentages. Curcumin treatment also significantly reduced macrophage infiltration of white adipose tissue, increased adipose tissue adiponectin production, and decreased hepatic nuclear factor-κB activity, hepatomegaly, and markers of hepatic inflammation. We therefore conclude that orally ingested curcumin reverses many of the inflammatory and metabolic derangements associated with obesity and improves glycemic control in mouse models of type 2 diabetes. This or related compounds warrant further investigation as novel adjunctive therapies for type 2 diabetes in man.
Fiscal Bargains, Political Institutions, and Economic Performance
Authors: Summerhill William R.
Published: April 2008

In “Bargaining for Absolutism,” Alejandra Irigoin and Regina Grafe argue three points of considerable interest to historians: political absolutism in Castile did not extend to fiscal matters; fiscal relations within Spain and its empire were characterized by bargaining, not directives from the crown; and the differences between Spanish and British imperial fiscal systems have been overstated. Their first and second points are a welcome corrective to oversimplified treatments of early modern Spanish fiscal politics, and echo findings on absolutism in France. In practice, absolutist sovereigns were not autocrats. They needed money to wage war and defend against predatory rivals, and had to exchange rent-generating privileges and monopolies in order to levy taxes and borrow. Irigoin and Grafe understate, however, the differences between fiscal relations in the British and Spanish empires. The institutions governing economic policy making at home were quite distinct in the two cases. After 1688 Britain relied heavily on Parliament for the formulation and approval of economic policies. The formal mechanisms by which the economic interests of different groups were articulated and brokered between Parliament and the government led to more efficient outcomes. In Spain, where the crown could selectively assign and abrogate property rights in a manner unchecked by formal political institutions, fiscal weakness and economic stagnation resulted. This institutional gap was reflected as well in the implementation of economic policy in their respective colonies. In this difference one can trace one important source of differing economic trajectories in the late colonial and early national periods.
The Writing Community: A New Model for the Creative Writing Classroom
Authors: Blythe Hal , Sweet Charlie
Published: April 2008

After creating a taxonomy of classroom approaches to the teaching of creative writing, the authors discuss a current practice they have employed, the writing community. The authors detail its success, place it within current pedagogical research into small-group and team-based learning, and suggest possible applications to allied fields.
Directional migration of neural crest cells in vivo is regulated by Syndecan-4/Rac1 and non-canonical Wnt signaling/RhoA
Authors: Matthews Helen K. , Marchant Lorena , Carmona-Fontaine Carlos , Kuriyama Sei , Larraín Juan , Holt Mark R. , Parsons Maddy , Mayor Roberto
Published: April 2008

Directed cell migration is crucial for development, but most of our current knowledge is derived from in vitro studies. We analyzed how neural crest (NC)cells migrate in the direction of their target during embryonic development. We show that the proteoglycan Syndecan-4 (Syn4) is expressed in the migrating neural crest of Xenopus and zebrafish embryos. Loss-of-function studies using an antisense morpholino against syn4 show that this molecule is required for NC migration, but not for NC induction. Inhibition of Syn4 does not affect the velocity of cell migration, but significantly reduces the directional migration of NC cells. Furthermore, we show that Syn4 and PCP signaling control the directional migration of NC cells by regulating the direction in which the cell protrusions are generated during migration. Finally, we perform FRET analysis of Cdc42, Rac and RhoA in vitro and in vivo after interfering with Syn4 and PCP signaling. This is the first time that FRET analysis of small GTPases has been performed in vivo. Our results show that Syn4 inhibits Rac activity, whereas PCP signaling promotes RhoA activity. In addition, we show that RhoA inhibits Rac in NC cells. We present a model in which Syn4 and PCP control directional NC migration by, at least in part,regulating membrane protrusions through the regulation of small GTPase activities.
Wt1negatively regulates β-catenin signaling during testis development
Authors: Chang Hao , Gao Fei , Guillou Florian , Taketo Makoto M. , Huff Vicki , Behringer Richard R.
Published: April 2008

β-Catenin, as an important effector of the canonical Wnt signaling pathway and as a regulator of cell adhesion, has been demonstrated to be involved in multiple developmental processes and tumorigenesis. β-Catenin expression was found mainly on the Sertoli cell membrane starting from embryonic day 15.5 in the developing testes. However, its potential role in Sertoli cells during testis formation has not been examined. To determine the function of β-catenin in Sertoli cells during testis formation, we either deleted β-catenin or expressed a constitutively active form ofβ-catenin in Sertoli cells. We found that deletion caused no detectable abnormalities. However, stabilization caused severe phenotypes, including testicular cord disruption, germ cell depletion and inhibition of Müllerian duct regression. β-Catenin stabilization caused changes in Sertoli cell identity and misregulation of inter-Sertoli cell contacts. As Wt1 conditional knockout in Sertoli cells causes similar phenotypes to our stabilized β-catenin mutants, we then investigated the relationship of Wt1 and β-catenin in Sertoli cells and found Wt1 inhibits β-catenin signaling in these cells during testis development. Wt1 deletion resulted in upregulation of β-catenin expression in Sertoli cells both in vitro and in vivo. Our study indicates that Sertoli cell expression of β-catenin is dispensable for testis development. However, the suppression of β-catenin signaling in these cells is essential for proper testis formation and Wt1 is a negative regulator of β-catenin signaling during this developmental process.
Stem cell researchers find their niche
Authors: Dzierzak Elaine , Enver Tariq
Published: April 2008

The EuroSTELLS Workshop `Stem Cell Niches', organised by Anna Bigas, Ernest Arenas and Pasqualino Loi, took place in January 2008 in Barcelona, Spain. The goal of the conference was to promote scientific collaboration and synergy between stem cell researchers worldwide and those in the EuroSTELLS consortia(an initiative of the European Science Foundation EUROCORES Programme), and to stimulate discussion of the latest results in the field of stem cell niches.