bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecular Nitrogen Fixation and Nitrogen Cycle in Nature
Authors: Virtanen Artturi I. 
Published: January 2012

The origin of nitrogen oxides in the atmosphere is discussed. Evidently only a small proportion of the nitrate- and nitrite-nitrogen found in the precipitation is formed through electric discharges from molecular nitrogen, photochemical nitrogen fixation being probably of greater importance. Formation of nitrate nitrogen through atmospheric oxidation of nitrous oxide (N2O) evaporating from the soil is also considered likely.
Determination of nitrogen compounds at different altitudes is indispensable for gaining information of the N2-fixation in the atmosphere and, in general, of the origin of nitrogen oxides and their decomposition. International co-operation is needed for this as well as for the quantitative determination of the nitrogen compounds removed from the soil by leaching and brought by waters into the seas.
The Abundance of O<sup>18</sup> in Atmospheric Water and Water Vapour
Authors: Dansgaard W. 
Published: January 2012

Investigations into the O18-abundance in the precipitation from a warm front reveal a distinct process of fractionation explainable by the unequal pressures of the saturated vapours of H2O16 and H2O18.
An explanation is given of the low O18-abundance in glacial waters.
A method of experimental investigation into the mechanism of the process of precipitation is discussed.
The Carbon Dioxide Exchange Between the North Atlantic Ocean and the Atmosphere
Authors: Dingle A. Nelson 
Published: January 2012

An approximate distribution of carbon dioxide exchange rates between the atmosphere and the North Atlantic Ocean is obtained for each month of the year on the basis of oceanographic data from Böhnecke’s Atlas and the assumption that atmospheric carbon dioxide maintains uniformly the volume percentage of .03. The results indicate the direction in which such an even volume percentage must be changed to approach equilibrium.
Aside from other influences, the ocean-atmosphere exchange of carbon dioxide and the trajectories of tropospheric air masses combine to produce high carbon dioxide content in mT and cP air and low carbon dioxide content in mP air. Since water vapor is at a minimum in the continental polar anticyclones during the polar night, the carbon dioxide probably serves as an effective inhibitor of the outgoing infrared radiation. This inhibiting effect may well serve to limit the intensity of cooling during an ice age; it probably has much less significance during inter-glacial periods.
The Role of the Gulf Stream in the Prediction of Iceberg Distribution in the North Atlantic
Authors: Post Louis A. 
Published: January 2012

A twenty-six year correlation is made between the yearly frequency fluctuations of icebergs south of the 48th parallel and the preseasonal sea surface temperature anomalies at Key West in the Straits of Florida and those of the Labrador Current three years later.
Good agreement among these variables is attributed to (1) the immediate effect of the relative strength of the Gulf Stream in barring the southward flow of bergs, and (2) the effect that varying strength of the Gulf Stream has upon the volume of warm water that escapes to the north, the effect in turn upon the rate of transport of icebergs, and the potential number eventually to be carried into the shipping lanes.
An iceberg prediction table is offered, making possible a prediction for the current year by using the sea temperature anomaly at Key West for March of this year together with the anomaly of three years earlier.
“The opinions and assertions contained herein are the private ones of the author and do not reflect the views of the Navy Department or the Naval Establishment.”
A Relation between Meteor Showers and the Rainfall of November and December
Authors: Bowen E. G. 
Published: January 2012

An examination is made of the November and December rainfall of approximately 300 stations distributed over the globe. Six singularities are found, five of which occur about 30 days after prominent meteor showers. This result is similar to one which has already been reported for the month of January. The remaining singularity on November 26 could be due to a daylight meteor stream from the direction of Virgo which has just been discovered in the Southern Hemisphere.
One of the better known meteor showers during the period investigated, namely the Giacobinids is known to have an orbital period of 6.6 years. A similar recurrence tendency is found in the rainfall 30 days later.
Herdmechanische Vorgänge bei einigen zirkumpazifischen Erdbeben
Authors: Mühlhäuser Siegfried 
Published: January 2012

Earthquake mechan'sms can be determined by a method given by P. Byerly and later developed by J. H. Hodgson and his collaborators. By a comparison with the tectonics of the earthquake region, it is possible in most cases to decide which of the two nodal planes represents the fault plane. As a certain arbitrariness cannot be avoided, also the stikes of the auxiliary planes have been given. If the arrows, indicating the direction of motion, have been drawn perpendicularly to the fault plane, this may mean that no auxiliary plane could be determined.
The mechanisms have been determined for 11 earthquakes in the years 1931–1950 in the Pacific area. It results that there is no general rule for the mechanisms, although the strikes of the fault planes in general coincide with the Circum-Pacific structural lines. The dip of the fault plane is as small as 31° in one case (earthquake no. 7), whereas the dip for the other cases is at least twice as large. Most of the earthquakes have a very large dip of the fault plane, in the range 70–88°. Dip values above 80° are especially frequent. The cases with smaller dip are localized to the north and northwest part of the Circum-Pacific belt.
The coastal earthquake belts of Central and South America exhibit a normal dip of the fault plane under the continent; this is also true for the northwest part of the Circum-Pacific belt. The conditions are similar at the southeast coast of Kamchatka, in Alaska, in western part of the Aleutians, and in the area between the Loyalty Islands and New Hebrides. In the other cases the fault plane dips toward the Pacific.
In northwestern Pacific belt the motions are often perpendicular to the strikes of the fault planes, whereas in the other areas the vertical motions are combined with horizontal displacements.
The number of observations for a single earthquake varies between 22 and 47. A few earthquakes in the Alpide belt have also been investigated, and comparisons with the results of other authors (A. R. Ritsema, 1955; A. N. Tandon, 1955) showed good agreement in spite of the fact that these authors have used 4–5 times as many observations. In a particularly favourable case (Hindu Kush, Jan. 9, 1933), 14 reliable observations of the initial motion of P waves gave the same result as 7 times as many observations, used by Ritsema. Nevertheless, as many reliable observations as possible should be used for earthquake mechanism studies.
Total Mineral Material, Acidity, Sulphur and Nitrogen in Rain and Snow at Kentville, Nova Scotia
Authors: Herman F. A. , Gorham E. 
Published: January 2012

Analyses of total ash, sulphur, pH, ammonia and nitrate nitrogen have been made on 23 monthly precipitation samples and 17 individual snow samples collected between June 1952 and May 1954 at Kentville, Nova Scotia, in a predominantly agricultural area. Mean annual supply of total mineral ash was 95 kg/ha, of sulphur 9.1 kg/ha, of ammonia nitrogen 2.8 kg/ha, and of nitrate nitrogen 1.1 kg/ha. Average pH was 5.7, and rains more acid than this exhibited higher levels of both nitrate and sulphur, and a marked correlation between the latter and ammonia.
Snow samples had much lower concentrations of ash, sulphur and nitrogen than rain samples collected in the same months, which may perhaps indicate a lower efficiency of snow flakes in removing materials from the atmosphere.
Experiments in Numerical Forecasting, Using Space-Smoothed Fields
Authors: Sigtryggsson Hlynur , Wiin-Nielsen Aksel 
Published: January 2012

A number of experiments in numerical forecasting using a technique based on the theory developed by Fjörtoft have been performed.
Section A contains the results of making barotropic 500 mb forecasts for 24 and 48 hours where the vorticity is advected in a space-smoothed field held constant in 12 or 24 hours. The results indicate that the forecasts in the mean are slightly less accurate as measured by the correlation coefficient between computed and observed changes. It is pointed out that the root mean square of the computed changes is smaller than for ordinary barotropic forecasts, especially for a large area.
Section B contains the results of an experiment to forecast the thickness field between 1,000 and 500 mb. The forecasts are based on the theory developed by Fjörtoft (1955). The flow at 500 mb has, however, in these forecasts been forecast with the barotropic model. The errors in these forecasts are of the same order of magnitude as in the barotropic forecasts. In the last part it is tried to relate the errors to physical defects of the model, especially the assumption of adiabatic motion.
Thermosensitive chitosan hydrogel for implantable drug delivery: Blending PVA to mitigate body response and promote bioavailability
Authors: Sun Jiali , Jiang Guoqiang , Wang Yujie , Ding Fuxin 
Published: January 2012

AbstractThermosensitive hydrogels promise to be the injectable implants for long‐term controlled drug release; however, body response to the implanted hydrogels and its unpredictable impacts on drug release complicates their applications. In the present study, hydrophilic polymer poly(vinyl alcohol) (PVA) was blended into the thermosensitive hydrogel composed of chitosan and glycerophosphate to mitigate the body responses and promote the drug bioavailability. The effects of PVA on the surface properties of the hydrogel were evaluated by zeta‐potential, water contact angle, and cell attachment. Body responses were explored by histological examination via subcutaneously implanting the hydrogels into Sprague‐Dawley rats. Drug release in vivo and bioavailability were determined with cyclosporine A (CsA) employed as the model drug. The results showed that, on one hand, the presence of PVA improved the surface hydrophilicity of the hydrogel and inhibited the cell attachment on the hydrogel, which alleviated the further cell infiltration and tissue integration in body; and on the other hand, blending of PVA led to the more rapid gel formation and more compact network, which resisted the dehydration and survived the hydrogel from cell division. These advantages benefited the controlled release and absorption of CsA, and contributed to the higher drug bioavailability. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Analysis of melt spinning master‐curves of low density polyethylene
Authors: Liang Ji‐Zhao , Zhong Lei , Wang Kejian 
Published: January 2012

AbstractThe extensional rheological properties of a low density polyethylene (LDPE) melt were studied by using melt spinning technique. Based on the extension properties of the LDPE melt under experimental conditions, the melt spinning master‐curves were plotted by introducing scaling factor b and the draw ratio λ. The scaling factor b shows the combination effects on the preorientation before extension, the unwrapping and orientation of molecular chains during extension. Several linear relationships between b and temperature, log b and the logarithm of extrusion flow rate v0 (log v0) have been investigated. By using the values of b and the reference curve, the extension viscosity curves with different temperature and extrusion flow rate could be calculated, thus the measurement range of melt spinning technique would be extended effectively. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Expression of Glial Cell Line‐Derived Neurotrophic Factor and its Receptors in Cultured Retinal Müller Cells Under High Glucose Circumstance
Authors: Zhu Xinping , Sun Yan , Wang Zhongping , Cui Weigang , Peng Yuwen , Li Ruixi 
Published: January 2012

AbstractThis study aimed to explore the effect of high glucose concentration on the expression of glial cell line‐derived neurotrophic factor (GDNF) and its family ligand receptors (GFRs) GFRα1 and GFRα2 in Müller cells and the protective role of GDNF in cultured Müller cells under high glucose circumstance. Cultured Müller cells (untreated or treated with 200 ng/mL of GDNF) were exposed to high glucose conditions (20 mmol/L glucose). We found that the expression levels of GDNF and GFRα1 mRNA and protein increased gradually over time under high glucose and exogenous GDNF‐treated conditions, whereas the upregulation in GFRα2 expression was observed only in the early stage of high glucose conditions. Exogenous GDNF not only decreased apoptosis in cultured Müller cells under high glucose circumstance, but also accelerated the levels and speed of synthesis of GDNF and GFRα1 proteins in Müller cells. These results suggest that Müller cells can synthesize GDNF and GFRs under high glucose conditions, and GDNF may play important role in protecting Müller cells during the early stage of diabetic retinopathy. The difference in GFRs expression indicated that GDNF and neurturin may exert different effects on Müller cells under high glucose circumstance. Anat Rec, 2012. © 2012 Wiley Periodicals, Inc.
Diazoxide Pretreatment Enhances L6 Skeletal Myoblast Survival and Inhibits Apoptosis Induced by Hydrogen Peroxide
Authors: Shao Su‐Xia , Zhang Lei , Chen Hong‐Xia , Liu Yan , Zhang Jin‐Ping , Chen Wei , Xue Guo‐Yu 
Published: January 2012

AbstractSkeletal myoblast (SKM) transplantation is a promising approach to regenerate tissue and improve the function of the injured heart. However, the number of survival cells transplanted to host myocardium is quite poor due to high rate of apoptosis; diazoxide (DZ) is a highly selective mito‐KATP channel opener that may reduce cell apoptosis by relieving reactive oxygen species (ROS) damage. The aim of this study is to explore the protective effects of DZ on L6 SKM damage induced by hydrogen peroxide (H2O2) in vitro. Different dose and time of H2O2 and DZ treatment were performed and only 24 hr of 1.00 mmol/L H2O2 treatment and 200 μmol/L DZ pretreatment for 30 min were used for further experiment. L6 SKMs were cultured and divided into control group (no treatment), H2O2 group (24 hr of 1.00 mmol/L H2O2 treatment) and DZ + H2O2 group (pretreated with 200 μmol/L DZ for 30 min before 24 hr of 1.00 mmol/L H2O2 treatment). Compared with control group, H2O2 treatment caused cell damage, increased lactate dehydrogenase release, cell apoptosis, and bax gene expression, while reduced cell proliferation and decreased bcl‐2 expression. DZ pretreatment may protect cells from damage induced by H2O2 and reduce cell apoptosis by increasing bcl‐2 and decreasing bax expression. DZ pretreatment may also promote cell proliferation measured by both PCNA expression and flow cytometry method. These results suggest that DZ may protect L6 SKMs from damage induced by H2O2 by maintaining integrity of cell membrane, reducing apoptosis and increasing proliferation in vitro. Anat Rec, 2012. © 2012 Wiley Periodicals, Inc.
Segmentation of female pelvic cavity in axial T2‐weighted MR images towards the 3D reconstruction
Authors: Ma Zhen , Jorge Renato Natal M. , Mascarenhas T. , Tavares João Manuel R.S. 
Published: January 2012

SUMMARYThe anatomies of pelvic structures are critical for the diagnosis of pelvic floor dysfunctions. However, because of the complex background, the imaging appearances of pelvic organs and muscles are frequently distorted by noise and partial volume effect. Magnetic resonance imaging with its clear imaging quality of the female pelvic cavity is preferred for many studies. As such, correct segmentations of the pelvic structures on MR images are required for accurate diagnoses. Effective algorithms for axial T2‐weighted MR images have been proposed, which are based on the imaging features of different structures and various image clues. In this paper, we review these algorithms and evaluate their performance, and discuss implementation issues and aspects towards constructing the three‐dimensional models. Copyright © 2012 John Wiley & Sons, Ltd.
Laser Control of Zeolite Nucleation
Authors: Navarro Marta , Mayoral Álvaro , Mateo Ester , Lahoz Ruth , de la Fuente Germán F. , Coronas Joaquín 
Published: January 2012

AbstractPrecursor solutions for the synthesis of zeolites are irradiated by means of a Nd‐YAG laser. These solutions are subsequently submitted to a hydrothermal treatment and the results analyzed by X‐ray diffraction and electron microscopy. Laser irradiation promotes the formation of silica nanoparticles that nucleate into zeolite (silicalite‐1), following a hydrothermal treatment. The average crystal size (in the 0.6–3.6 μm range) of the zeolite exponentially decreases as a function of laser irradiation time. In addition, a longer irradiation time results in a narrower crystal size distribution.
FAK and PAX‐illin get involved in leukocyte diapedesis
Authors: Luscinskas Francis W. 
Published: January 2012

AbstractA major focus of researchers studying leukocyte recruitment has been to identify and understand how cell surface endothelial adhesion molecules, cell‐to‐cell junctional protein complexes, secreted chemokines and chemoattractants, and the vessel basement membrane structure organization coordinate the process of leukocyte recruitment. As research expands beyond the components initially identified as being necessary for leukocyte recruitment, attention has turned to the structures that regulate endothelial cell‐to‐matrix adhesion. In this issue of the European Journal of Immunology, Parsons et al. [Eur. J. Immunol. 2012. 42: 436–446] identify new players in the regulation of neutrophil diapedesis (transendothelial migration), namely the focal adhesion proteins, paxillin and focal adhesion kinase (FAK). While understudied, and indeed previously underappreciated, in leukocyte diapedesis, this Commentary discusses how the work by Parsons et al. implicates FAK and paxillin in the proximal (leukocyte rolling) and distal (diapedesis) steps of the multistep adhesion cascade of leukocyte recruitment.
Recognition method for mid‐ to long‐term runoff forecasting factors based on global sensitivity analysis in the Nenjiang River Basin
Authors: Li Hongyan , Xie Miao , Jiang Shan 
Published: January 2012

AbstractMid‐ to long‐term runoff forecasting is important to China. Forecasting based on physical causes has become the trend of this field, and recognition of key factors is central to recent development. Here, global sensitivity analysis based on back‐propagation arithmetic was used to calculate the sensitivity of up to 24 factors that affect runoff in the Nenjiang River Basin. The following five indices were found to be key factors for mid‐ to long‐term runoff forecasting during flood season: Tibetan Plateau B, index of the strength of the East Asian trough, index of the area of the northern hemisphere polar vortex, zonal circulation index over the Eurasian continent and index of the strength of the subtropical high over the western Pacific. The hydrological climate of the study area and the rainfall–runoff laws were then analysed in conjunction with its geographical position and topographic condition. The rationality of the results can be demonstrated from the positive analysis point of view. The results of this study provide a general method for selection of mid‐ to long‐term runoff forecasting factors based on physical causes. Copyright © 2012 John Wiley & Sons, Ltd.
The COMT rs4680 Met allele contributes to long‐lasting low back pain, sciatica and disability after lumbar disc herniation
Authors: Jacobsen L.M. , Schistad E.I. , Storesund A. , Pedersen L.M. , Rygh L.J. , Røe C. , Gjerstad J. 
Published: January 2012

AbstractBackgroundThe COMT enzyme metabolizes catecholamines and thus modulates adrenergic, noradrenergic and dopaminergic signaling. A functional polymorphism in the gene encoding this enzyme, i.e. the COMT Val158Met SNP that reduces enzyme activity, has previously been linked to pain sensitivity.MethodsWe examined if the COMT Val158Met SNP could contribute to discogenic subacute low back pain and sciatica by comparing the frequency of the Val158Met genotypes of degenerative disc disease patients with healthy controls. Moreover, we examined if this SNP could predict the clinical outcome, i.e. the progression of pain and disability.ResultsThe present data demonstrated that there were no differences in COMT genotype frequencies between the newly diagnosed patients and controls. Analysis of pain and disability in the patients over time revealed, however, a significant or border‐line significant increase in McGill sensory score and Oswestry Disability Index (ODI) score for individuals with COMT Met/Met genotype. Furthermore, significant associations between the COMT Met‐allele and VAS activity score, McGill sensory score and ODI score were observed in the patients 6 months after inclusion.DiscussionAlthough the Val158Met SNP was not a risk factor for disc herniation, patients with Met/Met had more pain and slower recovery than those with Val/Met, which in turn also had more pain and slower recovery than those with Val/Val suggesting the SNP contributes to the progression of the symptoms of disc herniation.ConclusionWe conclude that the functional COMT Val158Met SNP contributes to long lasting low back pain, sciatica and disability after lumbar disc herniation.
THE EFFECT OF PARENTAL EMPLOYMENT ON CHILD SCHOOLING
Authors: Ermisch John , Francesconi Marco 
Published: January 2012

SUMMARYThis paper presents a model that provides conditions under which a causal interpretation can be given to the association between childhood parental employment and subsequent educational attainments of children. The key parameter comes from theconditional demand function for children's future earning capacity. Its identification rests on having data on siblings and assumptions about the timing of parents' knowledge of their children's endowments. In addition to sibling differences, the useof a fixed‐effects instrumental‐variables estimator identifies the parameter under weaker conditions. Empirical analysis informed by the model reveals a negative and significant effect on the child's educational attainment of the months of the mother's full‐time employment when the child was aged 0–5. The effect of the mother's part‐time employment is smaller and less well determined, but again negative. These results suggest that the substitution effect of the mother's employment dominates the income effects. Stronger adverse effects are found for children of less‐educated mothers. Copyright © 2012 John Wiley & Sons, Ltd.