bluuebunny/crossref_metadata_2025_split huggingface dataset:
Random hypergraph coloring algorithms and the weak chromatic number
Authors: Schmidt‐Pruzan Jeanette , Shamir Eli , Upfal Eli 
Published: May 2007

AbstractWe present a hypergraph coloring algorithm and analyze its performance in spaces of random hypergrpahs. In these spaces the number of colors used by our algorithm is almost surely within a small constant factor (less than 2) of the weak chromatic number of the hypergraph. This also establishes new upper and lower bounds for the weak chromatic number of uniform hypergraphs.
A generalized construction of chromatic index critical graphs from bipartite graphs
Authors: Plantholt Michael 
Published: May 2007

AbstractWe prove that any graph with maximum degree n which can be obtained by removing exactly 2n ‐ 1 edges from the join K1 + Kn, n is n‐critical. This generalizes special constructions of critical graphs by S. Fiorini and H. P. Yap, and suggests a possible extension of another general construction due to Yap.
Shortness parameters for planar graphs with faces of only one type
Authors: Owens P. J. 
Published: May 2007

AbstractWe construct infinite sequences of non‐Hamiltonian graphs and use them to show that the shortness exponent (or, in some cases, the shortness coefficient) is less than one for many classes of 3‐connected planar graphs whose faces are all r‐gons and whose vertices are all p‐valent or q‐valent, where p < q. Three of the five possible values of (r, p) are considered, namely (4.3). (3,3), and (3,4), in conjunction with most of the possible corresponding values of q.
On graphs with prescribed median I
Authors: Hendry G. R. T. 
Published: May 2007

AbstractThe distance of a vertex u in a connected graph H is the sum of all the distances from u to the other vertices of H. The median M(H) of H is the subgraph of H induced by the vertices of minimum distance. For any graph G, let f(G) denote the minimum order of a connected graph H satisfying M(H) ≅ G. It is shown that if G has n vertices and minimum degree δ then f(G) ⩽ 2n − δ + 1. Graphs having both median and center prescribed are constructed. It is also shown that if the vertices of a Kr are removed from a graph H, then at most r components of the resulting graph contain median vertices of H.
Lower‐bounds on the connectivities of a graph
Authors: Esfahanian Abdol H. 
Published: May 2007

AbstractThis article presents a study of the connectivities of a graph as a function of other graph parameters such as the number of vertices, the maximum degree, and the diameter. As a result, lower‐bounds on the connectivities of a graph as a function of these parameters are computed. These bounds could serve as sufficient conditions for a graph to be h‐edge‐connected or k‐connected. Consequently, the connectivity characteristics of many of the densest known graphs are determined.
The crossing number of K1,3,n and K2,3,n
Authors: Asano Kouhei 
Published: May 2007

AbstractIn this article, we will determine the crossing number of the complete tripartite graphs K1,3,n and K2,3,n. Our proof depends on Kleitman's results for the complete bipartite graphs [D. J. Kleitman, The crossing number of K5,n. J. Combinatorial Theory 9 (1970) 315‐323].
The bichromaticity of cylinder graphs and torus graphs
Authors: Pritikin Dan 
Published: May 2007

AbstractThe bichromaticity of a bipartite graph B is defined as the maximum value of r + s for which B has the complete bipartite graph Kr, s as a homomorphic image. We determine the bichromaticity of any bipartite cylinder graph C2n × Pm or torus graph C2n × C2m. In the process, we disprove a conjecture of Harary, Hsu, and Miller [2].
Analysis of erlotinib and its metabolites in rat tissue sections by MALDI quadrupole time‐of‐flight mass spectrometry
Authors: Signor Luca , Varesio Emmanuel , Staack Roland F. , Starke Volkmar , Richter Wolfgang F. , Hopfgartner Gérard 
Published: May 2007

AbstractA qualitative and quantitative analysis of erlotinib (RO0508231) and its metabolites was carried out on rat tissue sections from liver, spleen and muscle. Following oral administration at a dose of 5 mg/kg, samples were analyzed by matrix‐assisted laser desorption ionization (MALDI) with mass spectrometry (MS) using an orthogonal quadrupole time‐of‐flight instrument. The parent compound was detected in all tissues analyzed. The metabolites following drug O‐dealkylation could also be detected in liver sections. Sinapinic acid (SA) matrix combined with the dried‐droplet method resulted in better conditions for our analysis on tissues. Drug quantitation was investigated by the standard addition method and liquid chromatography‐tandem mass spectrometry (LC‐MS/MS) analysis on the tissue extracts. The presence of the parent compound and of its O‐demethylated metabolites was confirmed in all tissue types and their absolute amounts calculated. In liver the intact drug was found to be 3.76 ng/mg tissue, while in spleen and muscle 6‐ and 30‐fold lower values, respectively, were estimated. These results were compared with drug quantitation obtained by whole‐body autoradiography, which was found to be similar. The potential for direct quantitation on tissue sections in the presence of an internal standard was also investigated using MALDI‐MS. The use of α‐cyano‐4‐hydroxycinnamic acid (CHCA) as the matrix resulted in better linearity for the calibration curves obtained with reference solutions of the drug when compared to SA, but on tissue samples no reliable quantitative analysis was possible owing to the large variability in the signal response. MS imaging experiments using MALDI in MS/MS mode allowed visualizing the distribution of the parent compound in liver and spleen tissues. By calculating the ratio between the total ion intensities of MS images for liver and spleen sections, a value of 6 : 1 was found, which is in good agreement with the quantitative data obtained by LC‐MS/MS analysis. Copyright © 2007 John Wiley & Sons, Ltd.
Effect of ENSO on Queensland seasonal landfalling tropical cyclone activity
Authors: Flay Shaun , Nott Jonathan 
Published: May 2007

AbstractA statistical model for predicting seasonal tropical cyclone landfalls in Queensland, Australia using an index of the El Niño‐Southern Oscillation (ENSO) is presented. The approach uses a generalised linear model (GLM) to relate seasonal counts to the Southern Oscillation Index (SOI). A Bayesian methodology is employed to estimate parameters of the model. The available tropical cyclone record is first separated into historical (1910/1911–1959/1960) and instrumental (1960/1961–2004/2005) eras. Historical counts, which are considered to be less reliable observational sources, are used to specify informative prior distributions when fitting the GLM to instrumental counts with the Bayesian approach. The inclusion of historical information is found to lead to increased certainty in parameter estimates when compared to a model where historical counts are excluded and a non‐informative prior model used. Predictive distributions are given, which allow inferences on seasonal landfall activity, given pre‐seasonal values of the SOI. A cross‐validation procedure shows that the model incorporating historical information outperforms, in terms of mean‐squared prediction error, both the non‐informative prior model and a model without the SOI‐predictor (climatology). A trend analysis highlights possible decadal variability in the relationship between ENSO and seasonal tropical cyclone activity. Copyright © 2007 Royal Meteorological Society
Climate variability in Jordan
Authors: Freiwan Muwaffaq , Kadioǧlu Mikdat 
Published: May 2007

AbstractClimate variability in Jordan is very sensitive to water resources, which are at the verge of depletion because annual per‐capita water is at one of the lowest levels in the world. In order to address such sensitivity, it is necessary to examine effective meteorological factors such as annual, seasonal and monthly precipitation and extreme (maximum and minimum) temperature time series. Fourteen representative meteorological stations are chosen for the study of climate variability calculations in Jordan. Annual and monthly time series of precipitation, maximum and minimum temperatures are tested by the runs (Swed–Eisenhart) homogeneity test. Consequently, the sequential version of the Mann–Kendall rank trend and the linear trend tests are applied to the interannual means, coefficient of variation and skewness parameters. Signals of climate trends such as warming in maximum temperature, more statistically significant warming in minimum temperature, decreasing trends in daily temperature range and statistically insignificant decreasing precipitation trends are detected, which are enhanced by heat island, urbanization, pollution and aerosols effects. Two spells are recognized in the time series, where the first spell started in the early 1970s and the second beyond the year 1992 with a warming trend in maximum temperature and a farther warming in minimum temperature resulting in a decreasing trend in the diurnal temperature range that is associated with a slight decrease in precipitation. The interannual coefficient of variation of maximum and minimum temperatures reveals increasing trends in the majority of the stations while they exhibit an apparent decreasing trend in diurnal temperature range and a general, but insignificant, decreasing trend in precipitation is observed. Copyright © 2007 Royal Meteorological Society
Cloud‐radiative impacts on the tropical Indian Ocean associated with the evolution of ‘monsoon breaks’
Authors: Samala Basanta Kumar , Krishnan R. 
Published: May 2007

AbstractA detailed diagnostic analysis of a suite of observed datasets was carried out with a view to understand the importance of cloud‐radiative effects on the evolution of prolonged ‘monsoon breaks’ over the Indian region. The study particularly focuses on the role of clouds in affecting the sub‐seasonal/intra‐seasonal variability of sea surface temperature (SST) and atmospheric convection in the equatorial and south‐eastern tropical Indian Ocean (SETIO) during monsoon‐break transitions. A characteristic feature of the monsoon‐break evolution is the appearance of suppressed convection over the SETIO region nearly 7–10 days prior to the commencement of a break spell over India. It is seen from the present analysis that the lack of cloud cover over the SETIO during the ‘pre‐break’ phase leads to significant warming of the tropical Indian Ocean due to strong solar insolation at the surface. During the ‘pre‐break’ phase, the net cloud‐radiative forcing (NETCRF) at the surface is found to be typically around − 30 Wm−2 and the mean SST in the SETIO is about 29.3 °C. Following the transition to a monsoon‐break phase, the cloud amount increases by about 25% over the SETIO region in association with intensified convection. The NETCRF at the surface over the SETIO averaged during the ‘break’ phase is found to be about − 60 Wm−2 (i.e. a change of about − 30 Wm−2 from the ‘pre‐break’ phase). Consistent with the above change in the NETCRF, the SST in the SETIO shows a cooling of about 0.7 °C, although the mean SSTs during the ‘break’ phase remain as high as 28.6 °C. On the basis of the findings from this study, it is suggested that the SST warming during the ‘pre‐break’ phase plays a key role in maintaining high SST and allows sustained convection to occur over the SETIO during prolonged monsoon breaks. Copyright © 2007 Royal Meteorological Society
Weather regimes and sea surge variations over the Gulf of Lions (French Mediterranean coast) during the 20th century
Authors: Ullmann A. , Moron V. 
Published: May 2007

AbstractHourly sea surge variations observed at three tide‐gauge stations (Grau‐de‐la‐Dent(GD) located in the Rhône Delta, Sète(SE), and Port‐Vendres(PV)) around the Gulf of Lions are strongly correlated during the wintertime period (October to March) of 1986‐1995. Relationships between the early morning (6 a.m. UTC) sea surge observed at Grau‐de‐la‐Dent station and five weather regimes—Zonal (ZO), East‐Atlantic (EA), Greenland Above (GA), Blocking (BL), and Atlantic Ridge (AR)—over the northeast Atlantic and Europe (40°W–40°E, 30 –70°N) are analysed during the wintertime period of 1905‐2002. More than 75% of sea surges ≥ 40 cm occur during both of the weather regimes associated with a negative North Atlantic Oscillation(NAO) phase (41.2 and 34% during BL and GA weather regimes, respectively), ahead of low pressure travelling usually southeastward, on a stormtrack shifted south of 55°N. The relationships between monthly/seasonal frequency of weather regime and 75th percentile of sea surge at GD tend to strengthen during the 20th century: for example, correlation between seasonal frequencies of GA and 75th percentile of sea surge increases from 0.07 (not significant) in 1905–40 to 0.83 (signifiicant at the one‐sided 99% level) in 1974–2002. Copyright © 2007 Royal Meteorological Society
Spatial and temporal analysis of climatological data in Jordan
Authors: Freiwan Muwaffaq , Kadioglu Mikdat 
Published: May 2007

AbstractThis paper evaluates climate variability over Jordan by considering temporal and spatial variations on the basis of annual and seasonal meteorological variables including precipitation, relative humidity (RH), maximum and minimum temperatures over 30 years (1971–2000) at 16 representative observation stations over the whole country. The assessments are based on the statistical parameters such as the averages, coefficient of variation and skewness (SK). These parameters are mapped through the Kriging regional variability approach. Seasonal and annual parameter maps are presented and the climate variability interpretations are derived for the purpose of identifying climatologically homogenous precipitation regions. Climatic regions, temperature and humidity regimes, aridity and drought conditions in the country are determined, and the country is divided into three homogeneous precipitation regions. Copyright © 2007 Royal Meteorological Society
Andosols and soils with andic properties in the German soil taxonomy
Authors: Kleber Markus , Jahn Reinhold 
Published: May 2007

AbstractThe presence of soils with andic properties on German territory has been suspected for decades and there are numerous reports of sites where they may potentially occur. Andic properties, however, are not adequately represented by the German soil‐classification system. The German taxonomic category “Lockerbraunerde” has not been revised or reconciled with international taxonomic categories since the year 1957, when it was initially proposed. With this review, we show that there are true Andosols of both the silandic (allophane‐containing) and the aluandic (Al‐Humus‐dominated) type in Germany and that their properties differ substantially from other soils which merely exhibit low bulk density. By (1) comparing soil carbon storage between some German Andosols, Chernozems, and nonandic Cambisols with particularly low bulk density and (2) elucidation of the differential pedogenetic pathways leading to Andosol formation, we further demonstrate that Andosols are important objects of study in research issues of contemporary interest. We propose that appropriate measures be taken to lay the foundations for the protection and conservation of these soils, because they are valuable as archives of natural history and provide opportunities to study unique soil processes.
Impact of soil texture on temporal and spatial development of osmotic‐potential gradients between bulk soil and rhizosphere
Authors: Vetterlein Doris , Szegedi Krisztian , Stange Florian , Jahn Reinhold 
Published: May 2007

AbstractSolute transport from the bulk soil to the root surface is, apart from changes in soil moisture and plant nutrient uptake, a prerequisite for changes in soil osmotic potential (Ψo). According to the convection‐diffusion equation, solute transport depends on a number of parameters (soil moisture–release curve, hydraulic conductivity, tortuosity factor) which are functions of soil texture. It was thus hypothesized that soil texture should have an effect on the formation of Ψo gradients between bulk soil and the root surface. The knowledge about such gradients is important to evaluate water availability in the soil‐plant‐atmosphere continuum (SPAC).A linear compartment system with maize grown under controlled conditions in two texture treatments (T1, pure sand; T2, 80% sand, 20% silt) under low and high initial application of salts (S1, S2) was used to measure the development of Ψo gradients between bulk soil and the root surface by microscale soil‐solution sampling and TDR sensors.The differences in soil texture had a strong impact on the formation of Ψo gradients between bulk soil and the root surface at high and low initial salt application rate. At high initial salt application, a maximum osmotic‐potential gradient (ΔΨo) of –340 kPa was observed for the texture treatment T2 compared to ΔΨo of –180 in T1. The steeper gradients in osmotic potential in treatment T2 compared to T1 corresponded to higher cumulative water consumption in this treatment which can partly be explained by higher soil hydraulic conductivity in the range of soil matric potentials covered during the duration of the experiments. Differences between texture treatments in Ψo at the root surface did not result in differences in plant‐water relations measured as gas‐exchange parameters (transpiration rate, water‐use efficiency) and leaf osmotic potential. If soil osmotic and matric potential are regarded as additive in calculating the driving force for water movement from the soil into the root, the observed differences in water flux between treatments cannot be explained.
Effect of nutrient‐management practices on growth, fruiting pattern, and yield of Asiatic cotton (Gossypium arboreum L.)
Authors: Blaise Desouza , Ravindran Chandragiri Dwarakanath , Singh Jag Vir 
Published: May 2007

AbstractAsiatic cotton (Gossypium arboreum) is mostly grown in the rainfed regions of India. However, little is known about the effects of nutrient‐management practices on plant growth and fruiting pattern of Asiatic cotton. Therefore, plant growth and fruiting pattern under four nutrient‐management treatments, N, NPK, FYM (10 Mg ha–1), and INM (integrated nutrient management: a combination of NPK and FYM) were quantified during 2000–01 to 2002–03 (years 16 to 18 of a long‐term field experiment). Plants of the INM and FYM treatments were taller (68.4–149.5 cm) and had more main stem nodes per plant (30.5–44.5) as compared to N and NPK treatments. In treatment N, the shortest plants (50.9–83.6 cm) and the least number of fruiting structures were produced. Plants of the INM and FYM treatments accumulated more squares and bolls. Maximum boll production was 10–19 days earlier with the manure‐amended than the N and NPK treatments. Treatment N had the lowest seed cotton yield (639–790 kg ha–1), because of small boll size (1.48–1.73 g) and few open bolls. Seed cotton yield followed the trend: NPK (815–1278 kg ha–1) < INM (776–1551 kg ha–1) < FYM (902–1593 kg ha–1). Water stress and nutrient deficiencies (P and Zn in the N and Zn in the NPK treatments) as a consequence of nutrient depletion over the years may have decreased seed cotton yields in treatments that received mineral fertilizer alone in comparison with manure‐amended treatments. On a long‐term basis, FYM application should therefore form an integral part of nutrient recommendation.
Effects of throughfall and litterfall manipulation on concentrations of methylmercury and mercury in forest‐floor percolates
Authors: Hojdová Maria , Huang Jen‐How , Kalbitz Karsten , Matzner Egbert 
Published: May 2007

AbstractThe forest floor was shown to be an effective sink of atmospherically deposited methylmercury (MeHg) but less for total mercury (Hgtotal). We studied factors controlling the difference in dynamics of MeHg and Hgtotal in the forest floor by doubling the throughfall input and manipulating aboveground litter inputs (litter removal and doubling litter addition) in the snow‐free period in a Norway spruce forest in NE Bavaria, Germany, for 14 weeks. The MeHg concentrations in the forest‐floor percolates were not affected by any of the manipulation and ranged between 0.03 (Oa horizon) and 0.11 (Oi horizon) ng Hg L–1. The Hgtotal concentrations were largest in the Oa horizon (24 ng Hg L–1) and increased under double litterfall (statistically significant in the Oi horizon). Similarly, concentrations of dissolved organic C (DOC) increased after doubling of litterfall. The concentrations of Hgtotal and DOC correlated significantly in forest‐floor percolates from all plots. However, we did not find any effect of DOC on MeHg concentrations. The difference in the coupling of Hgtotal and MeHg to DOC might be one reason for the differences in the mobility of Hg species in forest floors with a lower mobility of MeHg not controlled by DOC.
Drought risk to agricultural land in Northeast and Central Germany
Authors: Schindler Uwe , Steidl Joerg , Müller Lothar , Eulenstein Frank , Thiere Jürgen 
Published: May 2007

AbstractAim of the study was the evaluation of the present state and further development of drought risk to agricultural sites in Northeast (NE) and Central Germany in consideration of climate changes. Based on the Medium Scale Agricultural Site Map, soil‐hydrological data were derived for heterogeneous soil areas. They refer to the landscapes in NE and Central Germany characterized by low precipitation, marked spatial soil heterogeneity, and a high share of hydromorphic soils. The soil data were linked with long‐term climate records of 368 stations for the period 1951–2000 as well as a climate scenario for the period 2001–2055. The plant water supply was calculated for three crop groups: cereals, root crops, and grass. The current and future development of drought risk of agricultural land of NE and Central Germany was evaluated. Starting in 1951, the water supply over the vegetation period has been decreasing with time for all crop groups up to now and may continue up to the year 2055 at most sites. However, there are also regions with increased plant water supply. The federal states of Brandenburg and Saxony‐Anhalt showed the strongest water deficit. Especially in these states, the plant water supply is strongly limited for cereals already today and probably may get worse for all crops in the future. On an average of the years, drought may limit plant growth in parts at >40% of agricultural land. In the federal states Mecklenburg‐Western Pomerania, Saxony, and Thuringia, the plant water supply mostly will stay in an approximately sufficient range due to higher precipitation and more favorable soil quality. The results are a background for the assessment of land‐use planning and evaluation of current and future soil‐ and site‐specific crop growing suitability on a medium scale.