bluuebunny/crossref_metadata_2025 huggingface dataset:
A Practical Method for the Prediction of the Surface Currents of the Ocean
Authors: Post Louis A.
Published: January 2012

A method is advanced for the prediction of surface currents based on the stability of computed dynamic currents. Wherever the latter are known and simultaneously the measured (geomagnetic) current and local wind direction, speed, and duration are known, the vector difference between the measured and the computed currents is assumed to be the portion of the current induced by the wind. The hypothesis is demonstrated empirically by a correlation of the above factors based on data obtained during a recent oceanographic survey. The predicted surface current vector is shown to be the resultant between a forecast wind-current and a permanent dynamic current. A new type of survey is proposed to make feasible the complete correlation of these factors.
Measurements of solar radiation at Lövånger in Sweden during the total eclipse 1945
Authors: Jerlov N. , Olsson H. , Schuepp W.
Published: January 2012

The meteorologic work at Lövånger (64° 22ʹ N, 21°19ʹ E) during the total eclipse on 9 July 1945 included continuous observations of the solar radiation. A Moll thermopile with 80 sets of junctions was used for measuring the radiant energy in different parts of the visible region. It was provided with a cylindrical screen at the upper end of which colour filters were introduced in succession. The device has been earlier described in detail (JOHNSON and OLSSON, 1944). Infra-red screening was achieved by means of the Schott and Genossen filter BG 19 in order to attain a high degree of accuracy in the visible range.
Reply
Authors: Syono S.
Published: January 2012

On my work Mr Jordan raised some questions, which are caused partly by the difference of definitions. For the formation of typhoon, we should consider two mechanisms, one is concerned with the initiation of the process, in other words the mechanism of trigger action, and another is the mechanism of the continuous development to revolving storms. In mathematical language, those corresponding to initial conditions and differential equations respectively.
Prognostic Equations for the Mean Motions of Simple Fluid Systems and Their Relation to the Theory of Large Scale Atmospheric Turbulence
Authors: Thompson Philip Duncan
Published: January 2012

By making use of the mathematical properties of certain special types of weighted means – taken either areawise or timewise – it has been shown that a variable’s deviation from its mean can be expressed in terms of the mean itself. This result has been used to derive a closed system of equations for the mean motion of an incompressible autobarotropic fluid. Comparison of the equations for area-averaged and time-averaged motion reveals that the area mean has certain advantages, inherent in the form of the equation for the unaveraged motion. The eddy transport for the case of “strong averaging” is contrasted with that derived from the classical “mixing-length” theory of eddy diffusion. The usual restrictions on the statistics of eddy fluctuations are found to be inconsistent with the unrestricted form of the eddy transport. Finally, it has been shown that these methods can be extended to the derivation of closed systems of equations for the mean motions of simple baroclinic fluids.
Composition of Atmospheric Precipitation in Sweden
Authors: Emanuelsson A. , Eriksson E. , Egner H.
Published: January 2012

Preliminary charts are presented based on two years of data, to demonstrate the geographic distribution over Sweden of the annual amounts of Na, Cl, K, Ca, NH3-N and NO3-N brought to the surface of the earth by precipitation. The ratios of these total amounts to the total amounts of Na deposited during the same time interval are shown to possess systematic geographic distribution patterns. Comparisons are made between these ratios and the corresponding quantities in sea water. The investigation is now being resumed to provide additional data from a larger number of stations and for longer time periods.
A Note on the Variation of Cosmic Ray Intensity Produced by an Electric Field
Authors: Lundquist S.
Published: January 2012

The variation of the cosmic ray intensity during a magnetic storm has been ascribed to the electrically polarized beam of particles from the sun. The loss of particles due to the total reflection in the electric field has been calculated. For comparison with observations, however, the change of intensity I per surface element dS, solid angle dΩ, and energy interval dW should be considered.
Serial Observations of Drift Currents in the Central North Atlantic Ocean
Authors: Stommel Henry
Published: January 2012

Between October 21, 1953 and February 9, 1954 a series of nearly continuous observations of wind-drift currents was made in the open ocean off Bermuda by means of drifting wireless-telemetering buoys. A rough plot of the position of each of these buoys relative to Bermuda was obtained by means of a mobile radio-direction-finding station.
Upper Air Temperatures over an Antarctic Station: A preliminary note
Authors: Schumacher Nils Jørgen
Published: January 2012

Typical features of antarctic upper air temperature distributions are demonstrated by means of average values and selected ascents. A great seasonal change in the height of the tropopause is pointed out. Attention is drawn to the remarkable agreement between observed stratospheric temperatures in winter and Dobson’s estimated values. The causes for the heating of the stratosphere in late winter and spring are discussed. The difference between the tropospheric temperatures in summer between Arctic and Antarctic is assumed to be due to the different value of the surface albedo. Rough estimates indicate that the absorption in the 9.7 μ band by ozone is of great significance to the observed stratospheric temperature contrast between the two polar regions in winter.
Numerical Forecasting with the Barotropic Model
Authors: Bolin Bert
Published: January 2012

The experiments with numerical forecasting using the barotropic model have been continued and a number of 24, 48 and 72 hour forecasts are presented. The initial data for these forecasts covered an area of about 9,000 by 12,000 km. The results indicate that the boundary influences have been reduced to be unimportant in the centre of the area in the 24-hour forecasts but they may still cause errors in the 72-hour forecasts. In view of the approximations made very good 72-hour forecasts have been obtained in some cases. The most successful one gave a correlation of 0.87 and a relative error of the forecast height changes of 0.58. Most of these extended forecasts should be of definite value in forecasting the weather. Large errors are, however, still obtained in some cases. The neglection of baroclinic process is one of the reasons for these errors but it is quite obvious that the largest errors are of a different nature. Experiments are at present conducted to find the sources of these errors. One line of this research is a general re-analysis of the assumptions made in deriving the barotropic model which is presented in the latter part of this paper. A number of improvements are suggested for further tests.
Microdetermination of CO2 in the Air, with Current Data for Scandinavia
Authors: Fonselius Stig , Koroleff Folke , Buch Kurt
Published: January 2012

Krogh and Brandt Rehbergs method for estimation of CO2 in atmospheric air has been investigated and modified. The method is used for continous investigation of the CO2 content of the air in Scandinavia. A permanent net of sampling stations has been established, 6 in Sweden, 4 in Finland, 3 in Norway and 2 in Denmark. The samples are taken three times each month. A simple method of taking air samples is described. Current data for November, December 1954 and January 1955 are published.
On the Correlation between Geomagnetic Activity and the Diurnal Variation of Cosmic Rays
Authors: Sandström Arne Eld
Published: January 2012

The cosmic ray measurements of K.-G. MALMFORS (1949) Oct. 1947—May 1950 have been studied with regard to the effect of geomagnetic activity on the diurnal variation. By means of the same data a study was also made of the secular phase shift first noticed by ELLIOT and THAMBYAPHILLAI (1953). The time of maximum has been found to decrease with increasing values of the international Kp-index, while the amplitude itself increases. These effects were studied for the registration period as a whole as well as for short intervals. The statistical fluctuations are too big for the study of intervals shorter than half a year. The secular phase shift is the same regardless of direction. Also the phase shift accompanying geomagnetic activity is independent of the direction of measurement. This is a good proof that both shifts are due to changes in the original direction of the primaries. It is also shown, that the secular phase shift is independent of the daily geomagnetic disturbances. Apparently two effects exist, both resulting in a change of the direction of the primary cosmic ray particles.
Physical Aspects of Rapid Cyclogenesis in the Gulf of Alaska
Authors: Winston Jay S.
Published: January 2012

The Gulf of Alaska is often the site of rapid development of large-scale cyclonic activity which can have profound effects on the long-wave pattern over North America in a matter of 24 to 48 hours. During much of the year such cyclogenesis takes place in the presence of a large heat source associated with rapid modification of cold Arctic air masses moving from Alaska out over the warmer sea surface of the Gulf. In order to get some insight into the mechanism of cyclogenesis under these special conditions a case of intense development occurring early in February 1950 has been studied, mainly in terms of the vorticity equation. The effects of barotropic redistribution of vorticity seem to account for much of the development. However, it is found that there exist pronounced fields of divergence and vertical motion, which particularly at the time of most rapid development reflect the influence of heat sources on the circulation.
On the Use of Space-Smoothing in Physical Weather Forecasting
Authors: Fjørtoft Ragnar
Published: January 2012

In section 1–2 a certain space-smoothing operation is defined and its usefulness in solving elliptic equations is demonstrated in the case of a Poisson equation. It leads to solutions in a closed form which possess the numerical simplicity of the ordinary iteration methods, but is converging more rapidly. The reverse operation of unsmoothing is also defined as far as it can be done, and it is mentioned that the combined processes of smoothing and unsmoothing are convenient tools for obtaining a spectral analysis of horizontal scalar fields, and also to remove systematical errors which are made when derivatives are taken as finite differences.

In sections 3–6 the application of smoothing is shown in the barotropic forecasting problem. At first a general theorem is proved concerning trajectories of two-dimensional non-divergent flow. It states that if the streamfunction ψ1 of such a flow can be decomposed into two components ψ2, α of which α is individually conserved in the ψ1-motion, then the displacements of the fluid particles up to any time can be found by at first displacing in the stationary flow αt=0 = const and then adding from the resulting positions the displacements in the flow with the streamfunction ψ2. The theorem is first applied to barotropic flow. In this case the first stationary field to displace in is the deviation between the actual and smoothed flow, while the second field to displace in is the smoothed flow.

The space-smoothing is next applied to an equation expressing the individual conservation of a quantity s in a two-dimensional non-divergent flow. The Reynolds term belonging to the smoothed equation is studied and found to depend essentially upon the deformation properties of the velocity field. The role of deformation for the net spectral flow of energy in the s-field is studied. The smoothing is in particular applied to the vorticity equation to show how this possibly can be utilized in the integration problem.

In sections 7–11 the baroclinic case is considered. In sections 7–8 is shown the fundamental role of deformation for the interchange of potential and kinetic energy. It is found that in the advective model there is direct proportionality between the change in total kinetic energy and total thermal wind energy, and also a direct proportionality between the change in kinetic energy for the vertically mean motion and the thermal wind energy.

In section 9 is discussed the possible importance of non-linear interference for the understanding of the creation and local distribution of disturbances in the atmosphere.

The integration problem is discussed in sections 10–12. At first an extension of the barotropic displacement rule is given for the vertically mean motion. The trajectory problem for levels other than the mean level is touched in section 12, and a simple non-advective model discussed shortly in section 11.
Automation of 500 mb Forecasts through Successive Numerical Map Analyses
Authors: Döös Bo R.
Published: January 2012

Two series of barotropic forecasts have been computed from numerically analysed maps. The first series consists of 31 forecasts and the second one of 4. Due to the fact that it is possible to obtain the forecasts directly from observed data, which are punched immediately after they are received, it is possible to save both time (3 à 4 hours) and personnel. The reliability of these forecasts seem to be at least as good as forecasts computed from conventionally analysed maps.
On the Sub-tropical Jet Stream and its Role in the Development of Large-scale Convection
Authors: Ramaswamy C.
Published: January 2012

This paper contains mainly the results of a synoptic and climatological study of the large-scale convection in northern India and Pakistan during the three months preceding the onset of the southwest monsoon. It has been shown that the sea-level and lower tropospheric charts give little clue to the development of the large-scale convection and that the latter is overwhelmingly determined by the divergence in the waves in the sub-tropical jet-stream. It has further been shown from detailed synoptic evidence that nor’westers, andhis and the majority of the thunderstorms without squalls in northern India and Pakistan in the pre-monsoon period are fundamentally the same phenomenon. The role of cold-air advection in the middle and upper troposphere in the development of large-scale convection has also been discussed. This study has further revealed that the regions of upper-divergence and convergence can be qualitatively located by identifying certain typical patterns on the high-level maps more than 12 hours before the usual time of commencement of convection and that, consequently, these maps can be used as effective tools in the issue of area-warnings against thunder in general and nor’westers and andhis in particular.

A general study has also been made of the large-scale convection in southeast Australia, Union of South Africa, Bechuanaland, Southern Rhodesia, northeast Argentina, Uruguay, southeast Brazil and southeast United States and the similarities between the large-scale convection in these countries and in Indo-Pakistan have been brought out. On the basis of these studies, it has been suggested that the jet stream plays the very important role of producing large-scale convection in the subtropics all over the world wherever it over-runs on its equatorward side, moist air possessing a high degree of latent instability.
The Sun’s General Magnetic Field
Authors: Alfvén Hannes
Published: January 2012

The solar magnetic field, including the interplanetary field is discussed. It is pointed out that in the absence of a theory of the Zeeman-effect in a turbulent atmosphere it is at present impossible to derive a value of the sun’s general magnetic field from spectroscopic measurements.

From the magneto-hydrodynamic theory of sunspots a value of the sun’s general magnetic field can be derived. Ananthakrisnan’s diagrams of the prominence activity can be interpreted as due to the same disturbance wave as is causing the sunspots. This gives further confirmation to the theory, which indicates magnetic field of Hp = 12 gauss.

The magnetic field outside the sun (interplanetary field) is certainly far from a dipole field. An approximate model of the field is tentatively suggested. This model is in agreement with information derived from cosmic ray and magnetic storm data and is also reconcilable with the coronal ray structure.
Variations in Insolation, General Circulation and Climate
Authors: Wexler H.
Published: January 2012

Two primary causes of variation in insolation—changes in solar output and in atmospheric transmission — are discussed, particularly with respect to basic changes in the mid- and high-latitude circulation pattern. Sunspot maxima in winter, on the average, are associated with greater tendency toward circulation blocks over the Northern Hemisphere and favorable conditions for heavy snow in regions known to have been glaciated in the past (Wisconsin) ice age. An explanation, based on an assumed greater insolation during sunspot maxima, is proposed. But summer weather conditions during sunspot maxima do not appear to favor preservation of the previous winter's accumulation of snow and ice. Hence an alternative explanation, based on decreased insolation accompanying periods of high atmospheric turbidity is proposed. The unequal response of continents and oceans to the decreased insolation causes heavy snow blankets to be deposited in areas known to have been glaciated and the lesser insolation in summer helps preserve a remnant of the snow until the next winter's contribution.
Gas Enclosures in a Temperate Glacier
Authors: Coachman L. K. , Hemmingsen E. , Scholander P. F.
Published: January 2012

Techniques are described for separating gas from glacier ice and analyzing for oxygen, nitrogen, and carbon dioxide. A systematic survey of a temperate glacier for enclosed gas showed 1) no general loss of gas from the glacier, but a specific loss of oxygen from the gas from the upper to the lower part of the glacier, and 2) the gas pressure and ice density increased from the upper to the lower part of the glacier. Present evidence indicates that a chemical reduction is responsible for the oxygen loss. The various data are discussed in relation to glacier mechanics.
A Consideration on Earth Tidal Change of Gravity
Authors: Nishimura Eiichi , Ichinohe Tokio , Nakagawa Ichiro
Published: January 2012

Gravimetric observations with the portable Worden gravimeter were made at three stations in our country to obtain accurate values for the earth tidal factor of gravity (G) and to detect, if possible, the local characters of these values. The observation period was respectively one month for each station, and the three stations were specially selected from the stand-point of diversity in conditions with regard to the supposed effect by ocean tides and subterranean structure. Judging from the observation results the G-values observed at three stations are generally well in accord with each other, but, if the numerals in the third figure of the G-valuc obtained can be assumed to have any significance, it should be said that the problem of the local character of the G-value remained unsolved and awaits the future investigation. The effect by ocean tides upon the G-value is discussed somewhat in detail, and the highly sensitive gravity variometer of double bifilar suspension type is also introduced.
Some Remarks About Nonlinear Oscillations In Tidal Channels
Authors: Kreiss H.
Published: January 2012

In tidal rivers one observes an unsymmetry between flood and ebbcurrent. This phenomenon is examined for channels with constant mean depth and mean cross-section area. The hydrodynamic equations are integrated over the vertical and it is shown that one is not allowed to introduce the usual simplifications (linearisation, neglection of friction) if one wants to describe this phenemenon. With the aid of a perturbation method the equations are integrated and it is shown that for sufficiently small ratio maximum of the flow/mean depth one can approximate the solution of by two harmonics. This approximation is examined in detail.
Upper-Air Analysis over Ocean Areas
Authors: Döös Bo R. , Eaton Max A.
Published: January 2012

From the results of a test of numerical analyses of 500-mb charts over an ocean area it is concluded that the number of ocean station vessels is a minimum and that supplementary upper air data is required to ensure continuously reliable upper air analyses. A method of determining the mean lapse rate by interpolation is presented by means of which heights of upper pressure surfaces can be extrapolated from observed values of surface pressure and temperature. An attempt is made to determine statistically the true mean error in the numerical analysis of upper-air charts.
Minimal Refractive Change Induced by Sutureless 23- and 25-Gauge Pars Plana Vitrectomy
Authors: Emanuelli Andrés , García-Gonzalez José M. , Berrocal María H. , Flynn Harry W.
Published: January 2012

BACKGROUND AND OBJECTIVE:

This study reports the induced refractive error after 23- and 25-gauge (G) pars plana vitrectomy (PPV).

PATIENTS AND METHODS:

In this non-randomized retrospective case series, refractive status was assessed with an autokeratorefractometer 1 week or more before and 6 months after surgery. Patients who had suture placement to close the sclerotomies were excluded from the study.

RESULTS:

Among the 50 patients (50 eyes), the mean age was 63 years (range: 42 to 76 years) and 57% were female. Thirty eyes underwent 23-G PPV and 20 eyes underwent 25-G PPV. The mean refractive change was +0.50 diopters (D) sphere, +0.25 D cylinders and the mean axis of cylinder change was 6° for the 23-G group; the mean refractive change was +0.12 D sphere, +0.12 D cylinders and the mean axis of cylinder change was 17° for the 25-G group.

CONCLUSION:

Following sutureless small-gauge vitrectomy, there were mild and minimally significant refractive changes in the 23-G and 25-G groups from baseline.
King Saul’s mysterious malady
Authors: Williams Gillian P. , Le Roux Magdel
Published: January 2012

This article investigates the ‘illness’ of King Saul (as narrated in the Old Testament). The ‘anti-Saul narrative’ states that ‘God’s spirit had left Saul’ and ‘an evil one had taken its place’ (1 Sm 16:14; also cf. e.g. of his behaviour in 1 Sm 19:24; 1 Sm 18:28−29). The latter years of Saul’s reign were marred by his pre-occupation with David’s growing popularity. He eventually became mentally unstable and suspected everyone of plotting against him. Saul’s battle against the Ammonites, as well as his last battle against the Philistines at Mount Gilboa, was fraught with difficulty. It is postulated that Saul experienced epileptic-like fits and assumedly suffered from some kind of ‘depression’ as a result of post-traumatic stress disorder (cf. 1 Sm 18:9; 1 Sm 18:28, 29; 1 Sm 19:24). This was possibly exacerbated by the enemy herem principle. Talmudic and other perspectives were also provided in the article where possible.
Use of a TTA Plate for Correction of Severe Patella Baja in a Chihuahua
Authors: Edwards George A. , Jackson Andrew H.
Published: January 2012

A 7 yr old spayed female Chihuahua presented for right hind limb lameness and reduced stifle range of motion. Radiographs showed a marked patella baja of the right stifle and evidence of a previous surgery to correct a medial patellar luxation. A tibial tuberosity osteotomy was performed to allow proximal translation of the tibial tuberosity, which was stabilized with a tibial tuberosity advancement plate. Four weeks postoperatively, lameness and articular range of motion were improved, and the use of anti-inflammatory and analgesic medications was discontinued. The dog was still ambulating well and had no lameness 12 mo postsurgically.
Heat Generation by Two Different Saw Blades Used for Tibial Plateau Leveling Osteotomies
Authors: Bachelez Andreas , Martinez Steven A.
Published: January 2012

During tibial plateau leveling osteotomy (TPLO) the saw blade produces frictional heat. The purpose of this study was to evaluate and compare heat generated by two TPLO blade designs (Slocum Enterprises [SE] and New Generation Devices [NDG]), with or without irrigation, on cadaveric canine tibias. Thirty-six paired tibias were used to continuously measure bone temperatures during osteotomy through both cortices (i.e., the cis and trans cortices). Each pair was assigned to either an irrigation or nonirrigation group during osteotomy, and each tibia within a pair was osteotomized using a different saw blade design. Saw blade temperatures were recorded and temperatures were compared for all combinations of blade type, cortex, and irrigation. In the cis cortex group, the SE blade generated more bone heat than the NGD blade (P=0.0258). Significant differences in temperature generation between saw blade types were seen only when the osteotomy site was not irrigated (P=0.0156). For all variables measured, bone and saw blade temperature generation was lower with irrigation (P<0.05). None of the osteotomies performed with either saw blade produced a critical duration of damaging temperature ranges in this study. Although saw blade design and irrigation influence heat generation during the TPLO, the potential for bone thermal damage during TPLO is low. The use of the NGD blade with irrigation is recommended.
Anesthesia and Perioperative Management of a Pneumonectomized Dog
Authors: Anagnostou Tilemahos L. , Pavlidou Kiriaki , Savvas Ioannis , Kazakos George M. , Papazoglou Lysimachos G. , Ververidis Haralabos N. , Raptopoulos Dimitris
Published: January 2012

Although left- or right-sided pneumonectomy is tolerated by normal dogs, complications impacting the respiratory, cardiovascular, and gastrointestinal systems are not uncommon. Pneumonectomy in dogs results in secondary changes in the remaining lung, which include: decreased compliance and vital capacity; and increased pulmonary vascular resistance potentially leading to right ventricular hypertrophy. Such alterations make the anesthetic management of an animal with one lung particularly challenging. This report describes a dog with a history of left pneumonectomy due to Aspergillus fumigatus pneumonia 3 yr before presentation. The dog presented with a vaginal wall prolapse, and surgical resection of the protruding vaginal wall, ovariectomy, and prophylactic gastropexy were performed. Anesthesia was induced with midazolam, fentanyl, and propofol and was maintained with isoflurane using intermittent positive pressure ventilation and a constant rate infusion of fentanyl. Epidural anesthesia was also used. Recovery and postoperative management were uncomplicated. Intensive hemodynamic and respiratory monitoring and appropriate response and treatment of any detected abnormalities, taking into consideration the pathophysiologic alterations occurring in a pneumonectomized animal, are required for successful perianesthetic management.
Urban Regeneration as Self‐Organisation
Authors: Batty Michael
Published: January 2012

Michael Batty redefines regeneration within the context of a wider system of urban reproduction. A spontaneous response to self‐organisation, regeneration is a force that can just as easily manifest itself in dereliction and decline. As part of a bottom‐up system, what role can there be for intervention by designers and policy‐makers? Batty suggests how urban planning needs to identify key points where small change can lead to massive change for the better, so as ‘to plant seeds that do not fall on stony ground’. Copyright © 2012 John Wiley & Sons, Ltd.
Iridium‐Catalyzed Asymmetric Hydrogenation of 3‐Substituted 2H‐1,4‐Benzoxazines
Authors: Gao Kai , Yu Chang‐Bin , Wang Duo‐Sheng , Zhou Yong‐Gui
Published: January 2012

The highly enantioselective hydrogenation of 3‐aryl‐2H‐1,4‐benzoxazines was achieved using the (cyclooctadiene)iridium chloride dimer/(S)‐SegPhos/iodine {[Ir(COD)Cl]2/(S)‐SegPhos/I2} system as catalyst with up to 92% ee. The 3‐styryl‐2H‐1,4‐benzoxazine derivatives were also hydrogenated by the iridium catalyst and Pd/C in two consecutive steps whereby 93–95% ee values were obtained.
Effect of additives, catalyst residues, and confining substrates on the fractionated crystallization of polypropylene droplets
Authors: Langhe Deepak S. , Hiltner Anne , Baer Eric
Published: January 2012

Fractionated crystallization of Ziegler‐Natta PP (ZN‐PP) droplets produced from ZN‐PP/polystyrene (PS) multilayered films resulted in four crystallization exotherms at 40, 64, 90, and 103°C. The origins of these crystallization peaks were investigated in this article. The nucleation of ZN‐PP droplets at various crystallization exotherms was attributed to (1) various additives in ZN‐PP and PS, (2) catalyst residues present in ZN‐PP, or (3) substrate nucleation by confining matrix. Effect of various additives on the fractionated crystallization an additive‐free grade of ZN‐PP (cPP) was investigated. Crystallization of cPP droplets from 200‐nm layers showed that Irganox was responsible for crystallization of droplets at 103°C. Irgafos and ZnS did not affect the crystallization of cPP droplets. We also investigated three grades of PP, which were synthesized using different catalysts. The PP grades were ZN‐PP, developmental PP (D‐PP) and metallocene PP (M‐PP). D‐PP droplets from 200‐nm layers showed crystallization at 100°C, while ZN‐PP resulted in crystallization at 90 and 103°C. It was suggested that the 90°C peak for ZN‐PP droplets was most likely due to the presence of Ziegler‐Natta catalyst residues. Crystallization of M‐PP droplets produced from 200 nm showed multiple crystallization exotherms (60 to 90°C). The effect of confining substrates on the fractionated crystallization of ZN‐PP droplets revealed heterogeneous nucleation by polycarbonate (PC) substrate. When the confining matrix was changed from polystyrene (PS) to polymethyl methacrylate (PMMA), the crystallization thermograms of ZN‐PP droplets were unaffected. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Study on the changing regularity of structure and properties of PC aged outdoor in western areas of China
Authors: Yonghao Pan , Mingjiao Yang , Shimin Han , Weibin Gao , Yi Dan
Published: January 2012

As an important engineering material, polycarbonate (PC) has been used widely. When exposed to the environment, PC will have aging process, which will reduce its performance and efficiency. This article studies the changing regularities of PCs structure and properties of ageing in western areas of China by measuring the change of intrinsic viscosity (IV), thermal decomposition temperature, glass transition temperature, and the groups within PC. The analysis of its IV, DSC, and thermo gravimetric analysis exhibited the same changing regularity, i.e., the aged PC (in Lasa, Yuli, and Jiangjin) experienced degradation and crosslinking, while degradation occurred earlier in the process of ageing, crosslinking predominated in later period. In addition, the results of UV absorption spectra and infrared absorption spectra showed the evidence of decomposition of the ester groups, resulting in the production of alcohol and phenol. And the results of mechanical tests indicated that the ductility disappeared mainly in the first year of outdoor aging. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Interrelation between preparation conditions, structure, and mechanical reinforcement in isoprene rubber filled with in situ generated silica
Authors: Bignotti F. , Borsacchi S. , de Santis R. , Geppi M. , Messori M. , Sudhakaran U. P.
Published: January 2012

The sol–gel technique was used to reinforce isoprene rubber (IR) by generating silica in situ from tetraethoxysilane (TEOS). The aim of the research was to elucidate the effect of the preparation conditions on the structural and morphological characteristics of silica and the resulting mechanical reinforcement. The structure of the in situ generated silica was analyzed by 29Si high‐resolution solid‐state NMR spectroscopy, which evidenced a high condensation degree of TEOS that decreased with increasing the sol–gel reaction time. The silica dispersion became less homogeneous as the TEOS content and the reaction time were increased. The incorporation of a coupling agent (OTES, octyltriethoxysilane) in the reaction mixture promoted full conversion of TEOS. Lower particle size, better silica dispersion, and higher filler‐matrix adhesion were noticed if the incorporation of OTES was delayed compared to TEOS. Uniaxial tensile tests evidenced that the tensile strength typically increased in the first 60 min of reaction and then leveled off. A similar behavior was observed for the high deformation stiffness, whereas at low deformations, the stiffness increased monotonically with the reaction time. In the vulcanizates with silica contents higher than 25 wt %, a drastic stiffness decrement was observed passing from low to high deformations. This reduction was ascribed to the disruption of the secondary filler network occurring in these materials when severely stretched. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Rheological properties and melt strength of LDPE during coextrusion process
Authors: Keawkanoksilp Chetporn , Apimonsiri Weerapol , Patcharaphun Somjate , Sombatsompop Narongrit
Published: January 2012

Rheological properties and mechanical strength of coextruded low‐density polyethyelene (LDPE) were studied in this work. The influences of die temperature, shear rate at skin and core layers, and number of extrusion passes at the core layer were of interest. The experimental results suggested that the viscosity and swelling behavior of LDPE coextrudate were more dependent on the shear rate of skin layer as compared with that of core layer. Increasing die temperature resulted in decreases in viscosity and die swell ratio. The reductions in viscosity and die swell ratio of the coextrudate for the reprocessing numbers 1 and 2 at the core layer arose from the disentanglement of long chain branching of LDPE molecules, while the increase of viscosity and die swell ratio for the reprocessing numbers 3 and 4 mainly involved an occurrence of crosslinking structure. For mechanical strength results, the changes in elongational stress for different shear rates, die temperature, and number of extrusion passes were in line well with the rheological measurements. That was, the higher the stored energies in polymer melts due to higher shear rates, the greater the amount of force required to conquer the elastic resistance. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Estimating local and regional population sizes for an endangered minnow, redside dace (Clinostomus elongatus), in Canada
Authors: Poos Mark , Lawrie David , TU Christine , Jackson Donald A. , Mandrak Nicholas E.
Published: January 2012

The Laurentian Great Lakes have undergone drastic declines in freshwater fishes, with 22 species having become extinct in the past century and many more currently at risk. One such species is the endangered minnow, the redside dace (Clinostomus elongatus), which is undergoing severe declines across its entire range.

Depletion and mark–recapture surveys were used to quantify population estimates of redside dace at several spatial scales (pool, reach and catchment) across several Great Lakes tributaries in Canada.

There was large variation in the local population estimates and the rate of occurrence of redside dace populations. In some cases, such as Gully Creek, a Lake Huron tributary, redside dace were widespread (9/10 of pools) but in low abundances (13.5 individuals per pool ± 5.09 ). In other cases, such as in the Don River, redside dace were highly localized (2/27 pools) but in relatively high abundance (99.2 individuals/pool ± 18.1).

Extrapolated population estimates at the catchment scale showed that three of the five study populations were below conservative estimates needed for long‐term population viability.

Differences in redside dace populations were driven by adjacent land‐use. Post‐hoc analyses revealed strong negative associations between population estimates and impervious land‐use (i.e. urbanization) at both the pool and sub‐catchment level.

Immediate recovery actions that will focus on eliminating chronic and episodic impacts of adjacent land‐use and improve connectivity are needed to help ensure redside dace, like many freshwater species in the Laurentian Great Lakes, remain a species at risk of – rather than facing – extinction.

Copyright © 2012 John Wiley & Sons, Ltd.
Morphology of the Distal Radius in Extant Hominoids and Fossil Hominins: Implications for the Evolution of Bipedalism
Authors: Tallman Melissa
Published: January 2012

One of the long‐standing arguments about the evolution of bipedality centers on the locomotor pattern used by the last common ancestor (LCA) of apes and humans. In particular, knuckle‐walking has been suggested as this locomotor pattern on the basis of shared morphology in the upper limb between African apes and humans and phylogenetic parsimony. Using three‐dimensional geometric morphometrics, this study tests whether the distal radius of extant hominoids is sufficient for determining locomotor pattern and the affiliations of Plio‐Pleistocene hominins to the extant taxa. Results indicate that while the entire radius differentiates the extant taxa very well by locomotor pattern, the distal radius fails to clearly differentiate the extant taxa. The sigmoid notch of the distal radius is the anatomical feature that differs most among the extant taxa, and its variability broadly correlates with necessary mobility at the wrist joint. Principal components and discriminant function analyses indicate that early hominins are affiliated with a variety of extant taxa with different locomotor patterns. Overall, the bony anatomy of the distal radius of early hominins points towards something adapted for a wide variety of locomotor postures. Anat Rec, 2012. © 2012 Wiley Periodicals, Inc.
Morphological Studies of the Pineal Gland in the Common Gull (Larus canus) Reveal Uncommon Features of Pinealocytes
Authors: Przybylska‐Gornowicz Barbara , Lewczuk Bogdan , Prusik Magdalena , Kalicki Miroslaw , Ziólkowska Natalia
Published: January 2012

The avian pineal is a directly photosensory organ taking part in the organization of the circadian and seasonal rhythms. It plays an important role in regulation of many behavior and physiological phenomena including migration. The aim of the study was to investigate morphology of the pineal organ in the common gull (Larus canus). The light and electron microscopic studies were performed on the pineals of juvenile birds living in natural conditions of the Baltic Sea coast, which have been untreatably injured during strong storms in autumn and qualified for euthanasia. The investigated pineals consisted of a wide, triangular, superficially localized distal part and a narrow, elongated proximal part, attached via the choroid plexus to the intercommissural region of the diencephalon. The accessory pineal tissue was localized caudally to the choroid plexus. Based on the histological criteria, the organ was classified as the solid‐follicular type. Two types of cells of fotoreceptory line were distinguished: rudimentary–receptor pinealocytes and secretory pinealocytes. Both types of cells were characterized by unusual features, which have been not previously described in avian pinealocytes: the presence of paracrystalline structures in the basal processes and their endings, the storage of glycogen in the form of large accumulations and the arrangement of mitochondria in clusters. Further studies on other species of wild water birds dwelling in condition of cold seas are necessary to explain if the described features of pinealocytes are specific for genus Larus, family Laridae or a larger group of water birds living in similar environmental conditions. Anat Rec, 2012. © 2012 Wiley Periodicals, Inc.
The Expression of Neuronal Nitric Oxide Synthase in the Brain of the Mouse During Embryogenesis
Authors: Ling Shucai , Zhou Jing , Rudd John A. , Hu Zhiying , Fang Marong
Published: January 2012

The distribution of neuronal nitric oxide synthase (nNOS) in the process of normal mouse brain growth from embryonic (E) Day 11 to postnatal (P) Day 1 was investigated by means of immunohistochemical and immunofluorescent methods. Our results demonstrated that nNOS positive neurons appeared early in superficial cortex at E11. At E13, nNOS positive neurons were located in lateral hypothalamus and amygdala, and temporarily in medullar and ventral hypothalamic neuroepithelia. From E15 to P0, nNOS positive neurons were distributed in superior and inferior colliculi, positive staining could also be seen in superior and inferior tectal neuroepithelium at E15. From E17 to birth, the medial geniculate nucleus had a high density of nNOS labeling. The distribution of nNOS gradually increased and extended laterally in embryo brain, which in turn implies that NO might be involved in the development of mouse brain. Anat Rec, 2012. © 2012 Wiley Periodicals, Inc.
Covalent Immobilization of Imidazolium Cations Inside a Silica Support: Palladium‐Catalyzed Olefin Hydrogenation
Authors: Wang Lei , Shylesh Sankaranarayanapillai , Dehe Daniel , Philippi Thomas , Dörr Gunder , Seifert Andreas , Zhou Zhou , Hartmann Martin , Klupp Taylor Robin N. , Jia Mingjun , Ernst Stefan , Thiel Werner R.
Published: January 2012

Mesoporous organosilica materials with different contents of bistrialkoxysilyl imidazolium salts in the framework were synthesized by a one‐step synthesis. Textural characterization of the materials confirmed that the morphology and surface properties of the imidazolium‐bridged organosilicas depended critically on the amount of organic groups in the framework, whereas solid‐state NMR characterization showed that the imidazolium fragments were integrated covalently into the framework. Further reaction of these materials with Pd(OAc)2, followed by reduction with NaBH4 yielded palladium nanoparticles stabilized in the mesoporous organosilicas. The stabilizing effect of the imidazolium cations and the mesostructure contributed to the high activity, selectivity, and stability of the palladium nanoparticles and allowed olefin hydrogenation under mild reaction conditions.
Synthetic and Mechanistic Aspects of the Immortal Ring‐Opening Polymerization of Lactide and Trimethylene Carbonate with New Homo‐ and Heteroleptic Tin(II)‐Phenolate Catalysts
Authors: Poirier Valentin , Roisnel Thierry , Sinbandhit Sourisak , Bochmann Manfred , Carpentier Jean‐François , Sarazin Yann
Published: January 2012

Several new heteroleptic SnII complexes supported by amino‐ether phenolate ligands [Sn{LOn}(Nu)] (LO1=2‐[(1,4,7,10‐tetraoxa‐13‐azacyclopentadecan‐13‐yl)methyl]‐4,6‐di‐tert‐butylphenolate, Nu=NMe2 (1), N(SiMe3)2 (3), OSiPh3 (6); LO2=2,4‐di‐tert‐butyl‐6‐(morpholinomethyl)phenolate, Nu=N(SiMe3)2 (7), OSiPh3 (8)) and the homoleptic Sn{LO1}2 (2) have been synthesized. The alkoxy derivatives [Sn{LO1}(OR)] (OR=OiPr (4), (S)‐OCH(CH3)CO2iPr (5)), which were generated by alcoholysis of the parent amido precursor, were stable in solution but could not be isolated. [Sn{LO1}]+[H2N{B(C6F5)3}2]− (9), a rare well‐defined, solvent‐free tin cation, was prepared in high yield. The X‐ray crystal structures of compounds 3, 6, and 8 were elucidated, and compounds 3, 6, 8, and 9 were further characterized by 119Sn Mössbauer spectroscopy. In the presence of iPrOH, compounds 1–5, 7, and 9 catalyzed the well‐controlled, immortal ring‐opening polymerization (iROP) of L‐lactide (L‐LA) with high activities (ca. 150–550 molL−LA molSn−1 h−1) for tin(II) complexes. The cationic compound 9 required a higher temperature (100 °C) than the neutral species (60 °C); monodisperse poly(L‐LA)s were obtained in all cases. The activities of the heteroleptic pre‐catalysts 1, 3, and 7 were virtually independent of the nature of the ancillary ligand, and, most strikingly, the homoleptic complex 2 was equally competent as a pre‐catalyst. Polymerization of trimethylene carbonate (TMC) occurs much more slowly, and not at all in the presence of LA; therefore, the generation of PLA‐PTMC copolymers is only possible if TMC is polymerized first. Mechanistic studies based on 1H and 119Sn{1H} NMR spectroscopy showed that the addition of an excess of iPrOH to compound 3 yielded a mixture of compound 4, compound [Sn(OiPr)2]n 10, and free {LO1}H in a dynamic temperature‐dependent and concentration‐dependent equilibrium. Upon further addition of L‐LA, two active species were detected, [Sn{LO1}(OPLLA)] (12) and [Sn(OPLLA)2] (14), which were also in fast equilibrium. Based on assignment of the 119Sn{1H} NMR spectrum, all of the species present in the ROP reaction were identified; starting from either the heteroleptic (1, 3, 7) or homoleptic (2) pre‐catalysts, both types of pre‐catalysts yielded the same active species. The catalytic inactivity of the siloxy derivative 6 confirmed that ROP catalysts of the type 1–5 could not operate according to an activated‐monomer mechanism. These mechanistic studies removed a number of ambiguities regarding the mechanism of the (i)ROPs of L‐LA and TMC promoted by industrially relevant homoleptic or heteroleptic SnII species.
Ferrocenes with Perfluorinated Side Chains and Ferrocenophanes with Fluorinated Handles
Authors: Roemer Max , Kang Youn Kyung , Chung Young Keun , Lentz Dieter
Published: January 2012

Trifluorovinyl groups are introduced onto the cyclopentadienyl ligands of ferrocene at the 1‐, 1,1′‐, and 1,2‐positions by Negishi‐type and Stille‐type coupling reactions of trifluorovinylzinc chloride and tri‐n‐butyltrifluorovinyl stannane with several iodoferrocenes. Modification of the trifluorovinyl group by nucleophilic substitution and [2+2] cycloaddition make them versatile building blocks for synthetic transformations. 1,1′‐Bis(trifluorovinyl) ferrocene reacts upon contact with silica or oxidizing agents and in the presence of a suitable nucleophile through a redox autocatalytic mechanism to afford ferrocenophanes with fluorinated handles. C(F)(H) and C(F)(OMe) moieties in α‐positions allowed further modifications to be performed by nucleophilic substitution of the fluorine atoms. A series of ferrocenes with fluorinated side chains and ferrocenophanes with fluorinated handles were isolated and characterized. Several molecular structures were determined by single‐crystal X‐ray diffraction. The influence of the fluorine substituents on the redox properties of the iron center were studied by cyclic voltammetry.
Controlled Synthesis and Enhanced Catalytic and Gas‐Sensing Properties of Tin Dioxide Nanoparticles with Exposed High‐Energy Facets
Authors: Wang Xue , Han Xiguang , Xie Shuifen , Kuang Qin , Jiang Yaqi , Zhang Subing , Mu Xiaoliang , Chen Guangxu , Xie Zhaoxiong , Zheng Lansun
Published: January 2012

A morphology evolution of SnO2 nanoparticles from low‐energy facets (i.e., {101} and {110}) to high‐energy facets (i.e., {111}) was achieved in a basic environment. In the proposed synthetic method, octahedral SnO2 nanoparticles enclosed by high‐energy {111} facets were successfully synthesized for the first time, and tetramethylammonium hydroxide was found to be crucial for the control of exposed facets. Furthermore, our experiments demonstrated that the SnO2 nanoparticles with exposed high‐energy facets, such as {221} or {111}, exhibited enhanced catalytic activity for the oxidation of CO and enhanced gas‐sensing properties due to their high chemical activity, which results from unsaturated coordination of surface atoms, superior to that of low‐energy facets. These results effectively demonstrate the significance of research into improving the physical and chemical properties of materials by tailoring exposed facets of nanomaterials.