bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regional Control of Chromatin Organization by Noncoding roX RNAs and the NURF Remodeling Complex in Drosophila melanogaster
Authors: Bai X , Larschan E , Kwon S Y , Badenhorst P , Kuroda M I 
Published: May 2007

Abstract
Dosage compensation in Drosophila is mediated by a histone-modifying complex that upregulates transcription of genes on the single male X chromosome. The male-specific lethal (MSL) complex contains at least five proteins and two noncoding roX (RNA on X) RNAs. The mechanism by which the MSL complex targets the X chromosome is not understood. Here we use a sensitized system to examine the function of roX genes on the X chromosome. In mutants that lack the NURF nucleosome remodeling complex, the male polytene X chromosome is severely distorted, appearing decondensed. This aberrant morphology is dependent on the MSL complex. Strikingly, roX mutations suppress the Nurf mutant phenotype regionally on the male X chromosome. Furthermore, a roX transgene induces disruption of local flanking autosomal chromatin in Nurf mutants. Taken together, these results demonstrate the potent capability of roX genes to organize large chromatin domains in cis, on the X chromosome. In addition to interacting functions at the level of chromosome morphology, we also find that NURF complex and MSL proteins have opposing effects on roX RNA transcription. Together, these results demonstrate the importance of a local balance between modifying activities that promote and antagonize chromatin compaction within defined chromatin domains in higher organisms.
A Validated Whole-Genome Association Study of Efficient Food Conversion in Cattle
Authors: Barendse W , Reverter A , Bunch R J , Harrison B E , Barris W , Thomas M B 
Published: May 2007

Abstract
The genetic factors that contribute to efficient food conversion are largely unknown. Several physiological systems are likely to be important, including basal metabolic rate, the generation of ATP, the regulation of growth and development, and the homeostatic control of body mass. Using whole-genome association, we found that DNA variants in or near proteins contributing to the background use of energy of the cell were 10 times as common as those affecting appetite and body-mass homeostasis. In addition, there was a genic contribution from the extracellular matrix and tissue structure, suggesting a trade-off between efficiency and tissue construction. Nevertheless, the largest group consisted of those involved in gene regulation or control of the phenotype. We found that the distribution of micro-RNA motifs was significantly different for the genetic variants associated with residual feed intake than for the genetic variants in total, although the distribution of promoter sequence motifs was not different. This suggests that certain subsets of micro-RNA are more important for the regulation of this trait. Successful validation depended on the sign of the allelic association in different populations rather than on the strength of the initial association or its size of effect.
Defective Decapentaplegic Signaling Results in Heart Overgrowth and Reduced Cardiac Output in Drosophila
Authors: Johnson Aaron N , Burnett Lindsey A , Sellin Julia , Paululat Achim , Newfeld Stuart J 
Published: May 2007

Abstract
During germ-band extension, Decapentaplegic (Dpp) signals from the dorsal ectoderm to maintain Tinman (Tin) expression in the underlying mesoderm. This signal specifies the cardiac field, and homologous genes (BMP2/4 and Nkx2.5) perform this function in mammals. We showed previously that a second Dpp signal from the dorsal ectoderm restricts the number of pericardial cells expressing the transcription factor Zfh1. Here we report that, via Zfh1, the second Dpp signal restricts the number of Odd-skipped-expressing and the number of Tin-expressing pericardial cells. Dpp also represses Tin expression independently of Zfh1, implicating a feed-forward mechanism in the regulation of Tin pericardial cell number. In the adjacent dorsal muscles, Dpp has the opposite effect. Dpp maintains Krüppel and Even-skipped expression required for muscle development. Our data show that Dpp refines the cardiac field by limiting the number of pericardial cells. This maintains the boundary between pericardial and dorsal muscle cells and defines the size of the heart. In the absence of the second Dpp signal, pericardial cells overgrow and this significantly reduces larval cardiac output. Our study suggests the existence of a second round of BMP signaling in mammalian heart development and that perhaps defects in this signal play a role in congenital heart defects.
Impact of Interpopulation Divergence on Additive and Dominance Variance in Hybrid Populations
Authors: Reif J C , Gumpert F-M , Fischer S , Melchinger A E 
Published: May 2007

Abstract
We present a theoretical proof that the ratio of the dominance vs. the additive variance decreases with increasing genetic divergence between two populations. While the dominance variance is the major component of the variance due to specific combining ability ($\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{{\sigma}}_{\mathrm{SCA}}^{2}\) \end{document}$), the additive variance is the major component of the variance due to general combining ability ($\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{{\sigma}}_{\mathrm{GCA}}^{2}\) \end{document}$). Therefore, we conclude that interpopulation improvement becomes more efficient with divergent than with genetically similar heterotic groups, because performance of superior hybrids can be predicted on the basis of general combining ability effects.
Prediction of Multilocus Identity-by-Descent
Authors: Hill William G , Hernández-Sánchez Jules 
Published: May 2007

AbstractPrevious studies have enabled exact prediction of probabilities of identity-by-descent (IBD) in random-mating populations for a few loci (up to four or so), with extension to more using approximate regression methods. Here we present a precise predictor of multiple-locus IBD using simple formulas based on exact results for two loci. In particular, the probability of non-IBD XABC at each of ordered loci A, B, and C can be well approximated by XABC = XABXBC/XB and generalizes to X123…k = X12X23…Xk−1,k/Xk−2, where X is the probability of non-IBD at each locus. Predictions from this chain rule are very precise with population bottlenecks and migration, but are rather poorer in the presence of mutation. From these coefficients, the probabilities of multilocus IBD and non-IBD can also be computed for genomic regions as functions of population size, time, and map distances. An approximate but simple recurrence formula is also developed, which generally is less accurate than the chain rule but is more robust with mutation. Used together with the chain rule it leads to explicit equations for non-IBD in a region. The results can be applied to detection of quantitative trait loci (QTL) by computing the probability of IBD at candidate loci in terms of identity-by-state at neighboring markers.
Correcting for Measurement Error in Individual Ancestry Estimates in Structured Association Tests
Authors: Divers Jasmin , Vaughan Laura K , Padilla Miguel A , Fernandez José R , Allison David B , Redden David T 
Published: May 2007

AbstractWe present theoretical explanations and show through simulation that the individual admixture proportion estimates obtained by using ancestry informative markers should be seen as an error-contaminated measurement of the underlying individual ancestry proportion. These estimates can be used in structured association tests as a control variable to limit type I error inflation or reduce loss of power due to population stratification observed in studies of admixed populations. However, the inclusion of such error-containing variables as covariates in regression models can bias parameter estimates and reduce ability to control for the confounding effect of admixture in genetic association tests. Measurement error correction methods offer a way to overcome this problem but require an a priori estimate of the measurement error variance. We show how an upper bound of this variance can be obtained, present four measurement error correction methods that are applicable to this problem, and conduct a simulation study to compare their utility in the case where the admixed population results from the intermating between two ancestral populations. Our results show that the quadratic measurement error correction (QMEC) method performs better than the other methods and maintains the type I error to its nominal level.
Assessment of Fish Yield in Patagonian Lakes (Argentina): Development and Application of Empirical Models
Authors: Baigún Claudio , Oldani Norberto , Madirolas Adrián , Colombo Gustavo Alvarez 
Published: May 2007

AbstractThe relationship between fish yield and basic limnological information is important to developing sustainable management policies for lake fisheries, particularly when fish data are lacking. Most Patagonian lake fisheries lack the basic statistical information provided by bycatch and effort data. We present a simple first‐order model of fish yield based on the relationship between fish biomass derived from hydroacoustic and gill‐net surveys developed for 18 small Patagonian lakes. Such a model can be used to develop sound management guidelines that can be applied to the many unsampled small lakes of Patagonia for which basic limnological data are available. We also evaluated the value of well‐known models developed from North American data sets. These models consistently underestimated fish yields in the Patagonian lakes, particularly as trophic level increased, illustrating the importance of using region‐specific data to develop fish management guidelines. The poor predictive performance of the North American models could be related to climatic, limnological, and fish community differences between North American and Patagonian lakes.
Influence of Rearing Temperature and Feeding Regime on Otolith Increment Deposition in Larval Ciscoes
Authors: Oyadomari Jason K. , Auer Nancy N. 
Published: May 2007

AbstractLarval ciscoes Coregonus artedi were reared in the laboratory from eggs collected in Lake Superior to validate the use of otolith microstructure for estimating age in days. Throughout a 75‐d period, water temperatures in two laboratory streams were increased progressively (from 5.6°C to 7.0°C and from 6.1°C to 12.3°C), mimicking the range larvae would probably experience in Lake Superior. Otolith increments were deposited at a rate not statistically different from one increment per day, starting from approximately 28 d posthatch, which was near the time of complete yolk sac absorption. Feeding frequency (twice daily, once daily, alternate days, and food deprivation) did not affect the prominence of subdaily marks (i.e., bands occurring in between daily increments), but a 5‐d period of food deprivation reduced increment contrast in some larvae. The reduced rations partly explained lower growth rates among larvae, and larvae with lower growth rates could not be aged as accurately by otolith analysis. An accessory check mark was induced by a sudden decrease in temperature but not by a reciprocal increase in temperature (between 6.9°C and 12.3°C). These results indicate the potential use of otolith analysis for aging larval ciscoes but are strongly cautionary about the method's limits at reduced growth rates. The results also suggest that patterns in otolith microstructure can be used to track shifts in environmental conditions, particularly temperature and feeding success, which may influence growth and survival of ciscoes during early life.
Summer Fish Community of the Coastal Northern Gulf of Mexico: Characterization of a Large‐Scale Trawl Survey
Authors: Lewis Michael , Jordan Stephen , Chancy Cynthia , Harwell Linda , Goodman Larry , Quarles Robert 
Published: May 2007

AbstractFish were collected by otter trawl at 367 sites from 119 coastal water bodies in the northern Gulf of Mexico, ranging from north‐central Florida to the Rio Grande, Texas, during the summer months of 1992‐1994. The fish were identified and enumerated, and tissue contaminants (in fillets), and external abnormalities (body, buccal, branchial, and ocular) were determined. Results were compared for sites east and west of the Mississippi River, within the Mississippi River, seven estuarine categories, and over 3 years. Approximately 31,000 individual fish were captured, representing 100 genera and 141 species. Thirteen species comprised 91% of the total abundance; abundances of 128 species were 1% or less. Pinfish Lagodon rhomboides, Atlantic croaker Micropogonias undulatus, Gulf menhaden Brevoortia patronus, and bay anchovy Anchoa mitchilli were the more dominant species. Fourteen species were collected from at least 10% of the sites; 85 species were captured at no more than 1% of the sites. Atlantic croakers and hardhead catfish Ariopsis felis were collected more frequently (>50% of sites). Indices of community structure from the full data set ranged as follows: 2.8 for the Shannon‐Wiener index, 0.90 for Simpson's index, and 0.56 for Pielou's evenness index. Chemical contaminants (predominantly total mercury and polychlorinated biphenyls [PCBs]) exceeded federal risk‐based consumption guidelines in 2.7% of fillets from four species. External abnormalities occurred on 17 species and approximately 1% of the total number of fish examined. Community structural properties varied temporally across years and spatially over estuarine categories and between areas east and west of the Mississippi River. Four distinct assemblages were identified by cluster analysis of species abundance. Cluster membership was associated with salinity, depth, dissolved oxygen, water clarity, and geographic area.
Oyster Grow‐Out Cages Function as Artificial Reefs for Temperate Fishes
Authors: Tallman Jessica C. , Forrester Graham E. 
Published: May 2007

AbstractWe compared relative fish density, growth, and disappearance rates (mortality plus emigration) at three oyster grow‐out sites, six natural rocky reefs, and one artificial reef purposely built for fish habitat. All sites were located within Narragansett Bay, Rhode Island. Trap surveys were conducted in the summer and autumn of 2004 and 2005 with a range of trap types designed to sample juvenile and adult fishes. Cunners Tautogolabrus adspersus were more abundant on natural rocky reefs and the artificial reef than on oyster grow‐out sites, whereas scup Stenotomus chrysops and tautogs Tautoga onitis displayed the opposite pattern and were most abundant on aquaculture sites. The relative density of black seabass Centropristis striata was similar in all habitats. A mark‐recapture study on scup indicated that this species grew at higher rates on natural rocky reefs but had a lower disappearance rate from aquaculture sites. Based on these criteria, the oyster grow‐out cages provide good‐quality habitat for fishes typically associated with hard‐bottom habitats. Habitat restoration programs for these fishes should thus consider use of grow‐out cages alongside other types of artificial reefs.
Seasonal Effects of Suspended Sediment on the Behavior of Juvenile Atlantic Salmon
Authors: Robertson Martha J. , Scruton David A. , Clarke Keith D. 
Published: May 2007

AbstractShort‐term increases in suspended sediment levels significantly influenced the behavior of juvenile Atlantic salmon in both fall and winter trials. The initial introduction of sediment (20 mg/L, or ≈15 nephelometric turbidity units [NTU]) increased foraging activity, which subsequently declined at sediment levels greater than 180 mg/L (≈35 NTU). Cover use also declined as fish emerged to forage. No fish returned to cover at sediment levels greater than 60 mg/L (≈22 NTU) in the fall trials, whereas some fish in the winter trials never emerged from cover. A rapid decline in territorial behavior and an avoidance response (i.e., alarm reaction) at sediment levels ranging from 60 to 180 mg/L (≈22‐42 NTU) were also noted in fall trials but not winter trials. Seasonal differences in the response of juvenile Atlantic salmon to suspended sediments may be explained by temperature‐related changes in diel activity patterns.
An Exquisitely Preserved Skeleton Representing a Primitive Sturgeon from the Upper Cretaceous Judith River Formation of Montana (Acipenseriformes: Acipenseridae: N. Gen. and Sp.)
Authors: Grande Lance , Hilton Eric J. 
Published: May 2007

A new species of sturgeon (Acipenseridae), †Psammorhynchus longipinnisn. gen. and sp., is described based on a single well-preserved specimen from the Upper Cretaceous Judith River Formation of Montana. Although based on only a single individual, the osteological detail we are able to describe for this species is extensive because of the completeness of the specimen, the relatively three-dimensional preservation, and the soft, loosely consolidated sandstone matrix in which it was contained (allowing some dissection of the specimen to reveal the internal bones of the head region). We prepared the specimen completely out of the matrix, and described the head region in stages of “dissection.” †Psammorhynchus longipinnisis the only fossil sturgeon to date that provides a relatively complete, reliable look at its osteology. Although there have previously been numerous and widespread reports of fossil sturgeons, the material is notoriously fragmentary and poorly preserved, consisting mostly of isolated scutes or pectoral spines (summarized here in an appendix) and it is of very limited use to phylogenetic studies of living sturgeon taxa. The only other described articulated skeleton of a fossil sturgeon is †Protoscaphirhynchus squamosusWilimovsky from the Upper Cretaceous Hell Creek Formation of Montana. That specimen (the only one known for the species) is a badly preserved, very poorly prepared skeleton showing little detail of the head region. It is interesting to note that the only known articulated fossil sturgeon skeletons (†Psammorhynchus longipinnisn. gen. and sp.; †Protoscaphirhynchus squamosusWilimovsky; and a third, yet undescribed specimen) were apparently each independently discovered in the abdominal regions of hadrosaurian dinosaurs (as was the Cretaceous paddlefish †Paleopsephurus wilsoniMacAlpin). Perhaps hadrosaur carcasses provided the right combination of taphonomic factors to protect acipenseriform carcasses from damage in high energy aquatic environments predominantly preferred by sturgeons. In any case, based on known specimens, sediments within hadrosaurs appear to have been the main preservational medium for articulated fossil sturgeon skeletons in North America.†Psammorhynchus longipinnisappears to be the sister taxon to the rest of Acipenseridae based on our preliminary analysis here. We will reevaluate this relationship elsewhere in our (Hilton, Grande, and Bemis) ongoing study of fossil and living Acipenseridae.
“Solvent Annealing” Effect in Polymer Solar Cells Based on Poly(3‐hexylthiophene) and Methanofullerenes
Authors: Li G. , Yao Y. , Yang H. , Shrotriya V. , Yang G. , Yang Y. 
Published: May 2007

AbstractThe self‐organization of the polymer in solar cells based on regioregular poly(3‐hexylthiophene) (RR‐P3HT):[6,6]‐phenyl C61‐butyric acid methyl ester (PCBM) is studied systematically as a function of the spin‐coating time ts (varied from 20–80 s), which controls the solvent annealing time ta, the time taken by the solvent to dry after the spin‐coating process. These blend films are characterized by photoluminescence spectroscopy, UV‐vis absorption spectroscopy, atomic force microscopy, and grazing incidence X‐ray diffraction (GIXRD) measurements. The results indicate that the π‐conjugated structure of RR‐P3HT in the films is optimally developed when ta is greater than 1 min (ts ∼ 50 s). For ts < 50 s, both the short‐circuit current (JSC) and the power conversion efficiency (PCE) of the corresponding polymer solar cells show a plateau region, whereas for 50 < ts < 55 s, the JSC and PCE values are significantly decreased, suggesting that there is a major change in the ordering of the polymer in this time window. The PCE decreases from 3.6 % for a film with a highly ordered π‐conjugated structure of RR‐P3HT to 1.2 % for a less‐ordered film. GIXRD results confirm the change in the ordering of the polymer. In particular, the incident photon‐to‐electron conversion efficiency spectrum of the less‐ordered solar cell shows a clear loss in both the overall magnitude and the long‐wavelength response. The solvent annealing effect is also studied for devices with different concentrations of PCBM (PCBM concentrations ranging from 25 to 67 wt %). Under “solvent annealing” conditions, the polymer is seen to be ordered even at 67 wt % PCBM loading. The open‐circuit voltage (VOC) is also affected by the ordering of the polymer and the PCBM loading in the active layer.
Iron‐Catalysed sp3–sp3 Cross‐Coupling Reactions of Unactivated Alkyl Halides with Alkyl Grignard Reagents
Authors: Dongol Krishna G. , Koh Huishi , Sau Manisankar , Chai Christina L. L. 
Published: May 2007

AbstractIron‐catalysed sp3–sp3 Kumada coupling with primary and secondary alkyl halides (RX) and alkyl Grignard reagents has been achieved in low to good yields depending on the nature of the R group.
When the neutral's dilemma hits: Routine problems, and the not‐so‐routine repercussions, of common arbitration conflicts
Authors: Meyer Judith P. 
Published: May 2007

AbstractRoutine arbitration matters breed potential conflicts for every arbitrator. In the second of two articles, Judith P. Meyer, of Haverford, Pa., presents scenarios that illustrate ethical situations. They provide guidance not only for neutrals, but also for parties dealing with arbitration processes and the problems that arise
Eichung eines Berthelotschen Verbrennungskalorimeters in elektrischen Einheiten mittels des Platinthermometers
Authors: Jaeger W. , von Steinwehr H. 
Published: May 2007

AbstractEinleitung. Prinzip der Eichung. Kalorimeter. Berücksichtigung der Temperatur der Umgebung. Trägheit des Thermometers und der Metallmassen des Kalorimeters (Trägheit, Einfluß der Eichungsmethode). Heizspule. Platinthermometer (Beschreibung, Eichung, Widerstandsmessung, Berechnung der Temperaturen aus den Nebenschlüssen). Messung der elektrischen Energie (Strom‐, Spannungs‐, Zeitmessung). Meßanordnung. Gang eines Versuches. Beispiel. Resultate (I. Eichung mit Quirlrührer im Nov. 1905, II. Eichung mit Ringrührer im Jan. 1906, III. Vergleichung und Umrechnung der Zahlen für die Bestimmung der Verbrennungswärme).
Weitere Mitteilungen über das Saitengalvanometer. Analyse der saitengalvanometrischen Kurven. Masse und Spannung des Quarzfadens und Widerstand gegen die Fadenbewegung
Authors: Einthoven W. 
Published: May 2007

AbstractAnalyse einiger Kurven. ‐ 7. Absolute Maße der Saitenmasse und des Widerstandes gegen die Saitenbewegung. ‐ 8. Die Spannung des Quarzfadens. ‐ 9. Die Brauchbarkeit des Saitengalvanometers für bestimmte Zwecke.
Die Eigendruckverbreiterung der Cs‐Linie 4555 Å
Authors: Moser Heribert , Schulz Henry 
Published: May 2007

AbstractDurch Anwendung direkter photoelektrischer Registrierung und Benützung absorptionsarmer Interferenz‐Schichten‐Spiegel wurde mit einem Perot‐Fabry‐Interferometer die Eigendruckverbreiterung der Cs‐Linie 4555 Å bei aufgelöster HfS gemessen. Das Linienprofil wurde zur Auswertung vom Apparateprofil und der Dopplerverbreiterung entzerrt. Die gefundenen Ergebnisse werden an Hand der bisher erschienenen theoretischen und experimentellen Arbeiten über die Eigendruckverbreiterung diskutiert.