bluuebunny/crossref_metadata_2025_split huggingface dataset:
The glucose and nitrogen starvation response of Bacillus licheniformis
Authors: Voigt Birgit , Hoi Le Thi , Jürgen Britta , Albrecht Dirk , Ehrenreich Armin , Veith Birgit , Evers Stefan , Maurer Karl‐Heinz , Hecker Michael , Schweder Thomas 
Published: February 2007

AbstractThe glucose and nitrogen starvation stimulons of Bacillus licheniformis were determined by transcriptome and proteome analyses. Under both starvation conditions, the main response of B. licheniformis was a switch to the usage of alternative nutrient sources. This was indicated by an induction of genes involved in the metabolism of C‐2 substrates during glucose limitation. In addition, B. licheniformis seems to be using other organic substances like amino acids and lipids as carbon sources when subjected to glucose starvation. This observation is supported by the induction of a high number of genes coding for proteins involved in amino acid and lipid degradation. During nitrogen starvation, genes for several proteases and peptidases involved in nitrate and nitrite assimilation were induced, which enables this bacterium to recruit nitrogen from alternative sources. Both starvation conditions led to a down‐regulation of transcription of most vegetative genes, which was subsequently reflected by a reduced synthesis of the corresponding proteins. A selected set of genes was induced by both starvation conditions. Among them were yvyD, citA and the putative methylcitrate shunt genes mmgD, mmgE and yqiQ. However, both starvation conditions did not induce a general SigmaB‐dependent stress response.
Synthesis and characterization of a vinyl‐terminated benzoxazine monomer and its blends with poly(ethylene oxide)
Authors: Huang Jieh‐Ming , Kuo Shiao‐Wei , Lee Yuan‐Jyh , Chang Feng‐Chih 
Published: February 2007

AbstractA vinyl‐terminated benzoxazine (VB‐a), which could be polymerized through ring‐opening polymerization, was synthesized through the Mannich condensation of bisphenol A, formaldehyde, and allylamine. This VB‐a monomer was then subjected to blending with poly(ethylene oxide) (PEO), followed by thermal curing, to form poly(VB‐a)/PEO blends. The specific interactions, miscibility, morphology, and thermal properties of these blends were investigated with Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry, dynamic mechanical analysis (DMA), and scanning electron microscopy (SEM). Before curing, we found that PEO was miscible with VB‐a, as evidenced by the existence of a single composition‐dependent glass transition temperature (Tg) for each composition. The FTIR spectra revealed the presence of hydrogen‐bonding interactions between the hydroxyl groups of poly(VB‐a) and the ether groups of PEO. Indeed, the ring‐opening reaction and subsequent polymerization of the benzoxazine were facilitated significantly by the presence of PEO. After curing, DMA results indicated that the 50/50 poly(VB‐a)/PEO blend exhibited two values of Tg: one broad peak appeared in the lower temperature region, whereas the other (at ca. 327 °C, in the higher temperature region) was higher than that of pristine poly(VB‐a) (301 °C). The presence of two glass transitions in the blend suggested that this blend system was only partially miscible. Moreover, SEM micrographs indicated that the poly(VB‐a)/PEO blends were heterogeneous. The volume fraction of PEO in the blends had a strong effect on the morphology. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 644–653, 2007
Illness stories on the internet: what do breast cancer patients want at the end of treatment?
Authors: Overberg R. I. , Alpay L. L. , Verhoef J. , Zwetsloot‐Schonk J. H. M. 
Published: February 2007

AbstractThe study aims to elicit user requirements for internet‐based applications disclosing fellow patients' illness stories for the benefit of breast cancer patients. Twenty‐six breast cancer patients, recruited via the Dutch Patient Organization for Breast Cancer, were interviewed about their preferences with regards to content, appearance, and search options concerning fellow patients' illness stories online. The interviews were analysed quantitatively (SPSS) and qualitatively (NVivo). Participants were mainly interested in fellow patients' experiences about how to cope with emotions, the impact of cancer in daily life, and physical discomforts. Most participants preferred a section of an illness story in text format about a specific topic; some of them wanted to be able to click on to the corresponding complete story, comprising of text alone or supported by voice or video clip. A majority of participants wanted to be able to select illness stories on the basis of several authors' features, i.e. treatment underwent, age, presence of metastases, time since diagnosis, and whether or not caring for children. Participants gave arguments for their preferences. The findings of this study will be used for designing an online trial with breast cancer patients aiming at refining the user requirements. Copyright © 2007 John Wiley & Sons, Ltd.
Modulated reflectivity probing of quantum dot and wetting layer states in InAs/GaInAsP/InP quantum dot laser structures
Authors: Sęk G. , Motyka M. , Kudrawiec R. , Misiewicz J. , Lelarge F. , Rousseau B. , Patriarche G. 
Published: February 2007

AbstractInAs/GaInAsP quantum dot (QD) structure grown by gas source molecular beam epitaxy on InP (100) substrate and designed as an active region for laser applications at 1.55 μm wavelength range has been investigated by optical spectroscopy in order to probe its energy electronic structure. The advantages of the modulated reflectivity measurements (in a form of photoreflectance – PR) have been used to detect the optical transitions related to all relevant parts of the structure like cladding material, quaternary barriers, wetting layer and finally quantum dots. Our theoretical analysis based on effective mass approximation calculations has shown that two high energy PR features above the QD ground state emission are related to heavy hole and light hole ground state transitions in the InAs wetting layer which is 3–4 monolayers thick. Moreover, the confinement potential for the dots is shallow enough to confine one electron state only and hence a single QD heavy hole transition has been observed in PR. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electromodulation spectroscopy of interband transitions in GaInNAsSb/GaAs quantum wells with high indium content
Authors: Kudrawiec R. , Yuen H. B. , Bank S. R. , Bae H. P. , Wistey M. A. , Harris James S. , Motyka M. , Gladysiewicz M. , Misiewicz J. 
Published: February 2007

AbstractContactless electroreflectance (CER) has been applied to study the optical transitions in as‐grown and annealed GaInNAsSb/GaAs QWs with 2.25% of nitrogen, high indium content (34%) and antimony flux varied from zero to 1.0 × 10–7 beam equivalent pressure torr (it corresponds to antimony content varied from 0 to 2%). It has been observed that broadening of the CER resonance related to the ground state transition decreases about three times (from ∼60 meV to 20 meV) after the incorporation of antimony into GaInNAs/GaAs QWs. Moreover, it has been found that the broadening parameter does not decrease with the rise of antimony content from 0.5% to 2.0%. It means that only 0.5% Sb is enough to improve the optical quality of GaInNAs/GaAs QWs. In addition, it has been observed that post growth annealing significantly improves the optical quality of these QWs and shifts to blue all QW transitions. By matching the QW transition energies with those obtained from theoretical calculations performed within the effective mass approximation the conduction band offset in these QWs has been found to be close to 80%. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Photo‐ and electro‐reflectance spectroscopy of δ‐doped GaAs/AlAs multiple quantum well structures
Authors: Čechavičius B. , Kavaliauskas J. , Krivaitė G. , Valušis G. , Seliuta D. , Halsall M. P. , Harrison P. 
Published: February 2007

AbstractThe photoreflectance (PR) and contactless electroreflectance (CER) spectroscopies have been used to study optical transitions, electronic structure and internal electric fields in beryllium δ‐doped GaAs/AlAs multiple quantum wells (MQWs) designed for terahertz sensors. QW widths ranged from 3 to 20 nm while doping densities varied from 2 × 1010 to 2.5 × 1012 cm–2. From the Franz–Keldysh oscillations in PR and CER spectra the surface electric field strength was established. The optical spectra were found to exhibit excitonic behaviour up to acceptor density of 2.5 × 1012 cm–2. The origin of spectral features was identified on a basis of their dependence on optical bias and calculations of electronic structure under electric field. Modulation spectra of lightly doped samples were found to be dominated by symmetry‐allowed excitonic transitions while in highly doped samples additional features associated with symmetry forbidden transitions, coming into play due to internal electric field, were revealed. Selective detection of terahertz radiation by sensors based on the studied structures is demonstrated. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modulation spectroscopy of AlGaN/GaN heterostructures: The influence of electron–hole interaction
Authors: Goldhahn R. , Winzer A. T. , Dadgar A. , Krost A. , Weidemann O. , Eickhoff M. 
Published: February 2007

AbstractThe present special issue of physica status solidi (a) contains contributions from the 2nd International Workshop on Modulation Spectroscopy of Semiconductor Structures (MS3), held in Wrocław, Poland, 29 June–1 July 2006.Editor's Choice is the article by R. Goldhahn et al. [1] which reports a detailed analysis of electroreflectance (ER) spectra for AlGaN/GaN heterostructures containing a two‐dimensional electron gas (2DEG). The cover picture depicts a color‐converted bias voltage map of the ER spectra around the GaN band gap recorded at a temperature of 5 K. The dark‐red color corresponds to a ΔR /R signal of 3 × 10–2. The Burstein–Moss (BM) shift and the position of the first Franz–Keldysh oscillation (FKO) are indicated.Rüdiger Goldhahn's research focuses on the further development of modulation spectroscopy methods for the characterization of bulk semiconductors and low‐dimensional systems. Andreas T. Winzer investigated the electro‐optical properties of III‐nitride heterostructures and is currently engaged in the solar cell production at Ersol Thin Film GmbH. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Preface: phys. stat. sol. (a) 204/2
Authors: Misiewicz Jan , Sitarek Piotr 
Published: February 2007

AbstractThe first International Workshop on Modulation Spectroscopy of Semiconductor Structures (MS3) in Wrocław (in the southwest part of Poland) at the beginning of July 2004 gathered almost 40 participants, half of them from abroad. This fruitful meeting resulted in a special issue of physica status solidi (a), Vol. 202, No. 7 (2005).The second meeting of scientists involved in all aspects of modulation spectroscopy of semiconductors, semiconductor heterostructures and devices – the 2nd MS3 Workshop – was organized at the same place (Wrocław, Poland) and almost at the same time of the year in 2006.The MS3 Workshop became a forum of discussion on the advantages of photoreflectance, electroreflectance, contactless electroreflectance, thermoreflectance, differential reflectance and wavelength‐modulated surface photovoltage spectroscopy. Applications of the above methods to investigate transistor, diode and laser structures including VCSELs, low‐dimensional structures of both wings of the spectrum, i.e. wide band gap materials like GaN, AlGaN and low band gap materials such as GaInN(Sb)As, InGaAs were demonstrated. A lot of time was also devoted to modulation spectroscopy of quantum dot structures.It is our great pleasure to publish the most interesting MS3 workshop presentations again in this special issue of physica status solidi (a).The organizers acknowledge the financial support of the Workshop by Wrocław University of Technology and the Foundation for Polish Science. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A study of cold fronts over the British Isles
Authors: Sansom H. W. 
Published: February 2007

AbstractFifty cold fronts are classified by means of two simultaneous aerological soundings. Two general categories are found:

Those in which the warm air is descending, usually forming a subsidence inversion. The name Katafront (following Bergeron) is applied to such fronts.
Fronts at which the warm air is ascending. These, which are named Anafronts, usually show no sharp discontinuity on a tephigram.
The two types of cold front give rise to quite different weather conditions. The changes in wind and temperature are generally much more abrupt at an anafront, where there is also much more precipitation. A katafront frequently brings a rapid clearance followed by fine weather.The variation of wind with height through the front is markedly different at the two types, the chief characteristics being:
Anafront: Rapid backing of wind with height; the component normal to the front decreases. The upper winds are inclined at a small angle (about 15°) to the line of the front.
Katafront: Slight backing with height; the normal component increases considerably. The upper winds are inclined at a large angle (about 40°) to the front. Consideration of the horizontal wind changes across the front leads to the expectation of troughs with strong cyclonic shear at anafronts, and the more rapid occlusion of katafronts.
Anafronts and katafronts are generally associated with different stages in the history of a cold front; an anafront is normally the initial state, but develops into a katafront later as the depression becomes more occluded. Katafronts are the more common type in this country, especially in summer.Calculations of the mean slope above the friction layer give values of about 1/70 for anafronts, and 1/300 for katafronts. The vertical velocity of the warm air at an anafront is of the order of 10 cm/sec upwards, while at a katafront it is about 2.5 cm/sec downwards. Vertical cross‐sections of wet‐bulb potential temperature show that there is often latent or convective instability at the nose of a katafront. This may be the explanation of the large ascending velocities found in this region by sailplane pilots.
Theory of airflow over mountains: IV‐separation of flow from the surface
Authors: Scorer R. S. 
Published: February 2007

AbstractSeparation of flow may be two‐dimensional when the wake or eddy is closed, or three‐dimensional when the air is continuously replaced. It often occurs at a salient edge. When it occurs the effect of the mountain on the high‐level flow is reduced. If the airflow is temporarily induced to follow the ground in an airstream favourable to separation, very large vertical velocities may result. Eddies may be shed periodically from the lee slope of a ridge. Lee waves inhibit separation and so do katabatic winds and downdraughts in heavy rain. Convection makes it more likely over lee slopes but inhibits it at the top of windward slopes.
Ice‐crystal counts and the freezing of water drops
Authors: Bigg E. K. 
Published: February 2007

AbstractAn analysis of the concentrations of ice crystals observed in a cold box by Smith and Heffernan (1954) in the course of 155 measurements is shown to provide support for values calculated for a given temperature from an equation used by Bigg (1953), thus verifying the analogy between freezing of airborne droplets and freezing of drops suspended in an insoluble liquid.
Fog precipitation on table mountain
Authors: Nagel J. F. 
Published: February 2007

AbstractFog precipitation on Table Mountain has been measured over a period of one year by means of two raingauges, one of which was equipped with a fog‐catcher. The evaluation of the records is complicated by the uncertainty of the fog precipitation during rain and drizzle. It is shown that satisfactory results can be obtained if at least two sets of instruments are installed on the mountain, one of them in the middle of the plateau and the other some 200 m lower.The fog precipitation for the year on the plateau was found to be 3,294 mmandthe rainfallto be 1,940 mm. The mean intensity of rainfall was 1.84 mm/hr and that of fog precipitation 3.75 mm/hr. Although the latter appears to be rather high, it is much lower than the value obtained theoretically. T h e discrepancy is accounted for by several errors in the measurements, which are discussed, and by fog precipitation supposed to occur on the slopes, which causes the air to reach the plateau with a smaller liquid‐water content than calculation indicates.
Theory of mountain waves of large amplitude
Authors: Scorer R. S. , Klieforth H. 
Published: February 2007

AbstractRotors are defined as regions containing flow in the opposite direction to the main stream and are shown to exist when the wave amplitude is large enough. Equations are derived for computing rotor flow in an infinitely deep atmosphere.The problem of choosing an appropriate second boundary condition in steady flow over a ridge is complicated when the amplitude is finite because the shape of obstacle obtained depends on the airstream characteristics as well as upon the mathematical form given to it. Probably under some actual conditions the oncoming airstream is modified by the presence of the mountain.Because of the great variety of airstreams and mountains no general case can be illustrated. The particular cases chosen illustrate rotor flow. These particular cases do, however, each represent a set of cases in which all the non‐dimensional numbers involved have the same value.Known cases of rotors in the Sierra Nevada and at Cross Fell are cited to illustrate the theory.
Measured radiative flux divergence near the ground at night
Authors: Funk J. P. 
Published: February 2007

AbstractNocturnal radiative flux divergence profiles in the lowest few metres have been directly measured and typical cases are presented in graphical form.Comparison of flux divergence calculated from radiation charts with measured divergence between 0·5 m and 1·5 m for a wide range of wind speeds and cloud conditions has shown the measured value to be up to 2·8 times larger than the calculated one. This discrepancy and others are attributed to the presence of haze.Since radiative cooling rates were generally found to be higher than actual rates, development of the nocturnal inversion near the surface is shown to be predominantly caused by radiation, with eddy cooling supplanted in the lowest layers by eddy warming.Periods of radiative warming sometimes associated with long‐period (40 min) air‐temperature fluctuations were found. A possible explanation is given for these and for fog formation in airlayers not in direct contact with the surface.Comparisons are given between radiative ground temperatures and those obtained from standard grass thermometers.
The expansion of clusters of particles in the atmosphere
Authors: Smith F. B. , Hay J. S. 
Published: February 2007

AbstractIn this paper, the problem of the spatial expansion of a cluster of particles under the action of turbulence is investigated. The basic difficulty, that this form of diffusion depends on the Lagrangian properties of the turbulent field, is met by the assumption that the Lagrangian and Eulerian time‐correlograms are functionally similar. In consequence, it is possible to solve the equation governing the cluster's expansion to give prediction laws expressed only in terms of easily measured parameters of the turbulence. The application of the full solution is lengthy but a simple working approximation follows from the fact that over an important part of the expansion at which the size of the cluster is of the same order of magnitude as the Eulerian length‐scale, the rate of expansion is approximately constant and is proportional to the square of the intensity of turbulence whilst independent of the length scale itself. Experiments to test these formulae have been carried out on the diffusion of clusters of Lycopodium spores over a few hundred metres downwind travel near the ground, and the diffusion of long crosswind clouds of aircraft‐released fluorescent particles, sampled along the vertical, after several kilometres travel in the free atmosphere. Whilst the experiments are few in number and the conditions often did not strictly conform to the conditions of isotropy and homogeneity required by the theory, the results are satisfactorily consistent with the prediction formulae and imply an effectively constant ratio between the scales of the Lagrangian and Eulerian time‐correlograms.
Natural convection in the earth's boundary layer
Authors: Townsend A. A. 
Published: February 2007

AbstractThe relation between the vertical distributions of mean temperature in buoyant convection over a horizontal surface as observed in the atmosphere and in the laboratory is examined. Some measurements by Webb, obtained in conditions of strong instability, are analysed and shown to be consistent with three distinct regions of flow, distinguished by their heat‐transfer characteristics. They are:

a region of forced convection with temperature gradient inversely proportional to height (negative Richardson number less than 0·02);
a region of mixed (or free) convection with temperature gradient inversely proportional to the 4/3‐power of the height (negative Richardson number between 0·03 and 1·0) and
a region of natural convection with temperature gradient inversely proportional to the square of the height (negative Richardson number greater than 1·0).
Reasons for the existence and properties of the last two regions are discussed briefly.
Some observed properties of medium‐scale diffusion in the atmosphere
Authors: Pasquill F. 
Published: February 2007

AbstractDiffusion experiments using fluorescent particles are described and data on travel and horizontal spread over distances 10 to 80 miles are summarized.Good vertical mixing evidently counteracts the tendency for a cloud of particles to be sheared according to the wind profile. The effective velocity of the cloud is then close to the mean velocity through the layer of mixing, but some unexplained discrepancies in direction have been encountered. The shearing which can occur in the absence of vertical mixing will become effective as a horizontal spread through the action of subsequent vertical mixing.The data are insufficient to allow any general conclusion to be reached about the relative importance of horizontal turbulence and vertical shear in promoting horizontal spread.
Radiative transport properties of fogs
Authors: Brinkworth B. J. 
Published: February 2007

AbstractAll clean fogs exhibit a common gross‐phase function for scattering when the mean‐square particle size is large enough to produce non‐selectivity with respect to the wavelengths of the radiation. Then the transport mean free path varies only with the attenuation coefficient for single scattering and is shown to be approximately equal to the daytime visual range, as given by Koschmieder's relation.