bluuebunny/crossref_metadata_2025 huggingface dataset:
Nonisothermal crystallization behaviors of polypropylene with α/β nucleating agents
Authors: Bai Hongwei , Wang Yong , Liu Li , Zhang Jihong , Han Liang
Published: July 2008

In this work, the nonisothermal crystallization and subsequent melting behaviors of polypropylene (PP) nucleated with different nucleating agents (NAs) have been studied. α‐phase NA 1,3:2,4‐bis (3,4‐dimethylbenzylidene) sorbitol (DMDBS, Millad 3988), β‐phase NA aryl amides compound (TMB‐5), and their compounds were introduced into PP matrix, respectively. The results show that the nonisothermal crystallization behaviors and crystalline structures of PP with compounded NAs are dependent on the composition of NAs. In the sample of PP with 0.1 wt % DMDBS and 0.1 wt % TMB‐5, the nucleation efficiency (NE) of TMB‐5 is much higher than that of DMDBS and PP crystallizes mainly nucleated by TMB‐5, and in this condition, β‐phase PP is the main crystallization structure. For the sample of PP with 0.2 wt % DMDBS and 0.2 wt % TMB‐5, 0.2 wt % DMDBS has higher NE than 0.2 wt % TMB5, and α‐phase is the main crystalline structure. The cooling rate is proved to be very important in controlling the nonisothermal crystallization behavior and the final crystalline structure of nucleated PP. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1853–1867, 2008
Analysis of cyanoacrylate ultraviolet absorbers using liquid chromatography/atmospheric pressure chemical ionization mass spectrometry: influence of fragmentor voltage and solvent on ionization and fragmentation behaviors
Authors: Choi Sung‐Seen , Song Min Ju
Published: July 2008

Ionization efficiencies and fragmentation patterns of cyanoacrylate ultraviolet (UV) absorbers, Uvinul 3035 and Uvinul 3039, were studied using liquid chromatography/atmospheric pressure chemical ionization mass spectrometry (LC/APCI‐MS). Solvent effect on the ionization efficiencies was investigated using methanol, ethanol, acetone, and chloroform. The fragmentation patterns were also investigated by varying the fragmentor voltage. Solvated ions, the [M+H + solvent]+ of methanol, ethanol, and acetone were detected, but the [M+H + chloroform]+ ion was not observed. For Uvinul 3039 in chloroform, the [M+CHCl2]+ ion was detected instead of the solvated ion. Relative abundance of the solvated ion was decreased by increasing the fragmentor voltage. Fragment ions of m/z 250, 232, and 204 were detected and their abundance increased with an increase in the fragmentor voltage. The m/z 250 ion can be accounted for by a McLafferty rearrangement. The fragment ions of m/z 232 and 204 were formed not only by subsequent fragmentations of the m/z 250 ion, but also by ion‐molecule reactions of solvent ion and neutral analyte. Copyright © 2008 John Wiley & Sons, Ltd.
Robust control of uncertain systems with polynomial nonlinearity by output feedback
Authors: Lei Hao , Lin Wei
Published: July 2008

The problem of global robust stabilization by output feedback is investigated for two classes of uncertain systems with polynomial nonlinearity—one is with controllable/observable linearization and the other is not. The uncertainties in the systems are assumed to be dominated by both lower‐ and higher‐order nonlinearities multiplying by an output‐dependent growth rate. There are two ingredients in this study. One is to exploit the idea of how to handle polynomial growth conditions via homogeneity and domination without introducing an observer gain updated law. The other is the development of a recursive design algorithm for the construction of reduced‐order observers, which is not only interesting in its own right but also has a valid counterpart, capable of dealing with strongly nonlinear systems, even lack of uniform observability and smooth stabilizability. Copyright © 2008 John Wiley & Sons, Ltd.
Healing with ‘spirits’: ethical issues arising from neoshamanistic practices and similar forms of alternative healing
Authors: Mayer Gerhard
Published: July 2008

The communication with spirits in the ‘non‐ordinary reality’ (NOR) represents a central element in neoshamanistic treatment methods. Shamanistic practitioners each have their own personal ‘power animals’ or ‘spirit helpers’. These provide information that is used both for diagnostic purposes and for everyday practical decisions. Even in the healing rituals, it is not the shamanistic practitioners who initiate the healing process but thespirits. On the one hand, this viewpoint leads to a certain humility, but on the other hand, it also presents the question of responsibility because the helping spirits from the NOR are made into authorities that define the actual happenings.

After the introductory part, which will introduce the basics of neoshamanistic practice, ethical problems that may occur in this context will be discussed on the basis of data from a qualitative study on neoshamanism in Germany. These problems are not restricted to neoshamanism and can also be found in other related practices of alternative healing but can be clarified particularly well by this example. Copyright © 2008 John Wiley & Sons, Ltd.
Social identification, stress and citizenship in teams: a five‐phase longitudinal study
Authors: Haslam S. Alexander , Jetten Jolanda , Waghorn Claire
Published: July 2008

Previous theorizing and research in the social identity tradition suggests that identification with a group is a major determinant both of individuals' citizenship behaviour and their experience of, and responses to, social and organizational stressors. To provide a longitudinal exploration of these processes, the present study examines the patterns of group identification, work‐related attitudes and burnout within two theatre production teams on five occasions, from audition to post‐performance. As predicted, identification with the production team at the outset predicted positive perceptions and attitudes at the productions' conclusion. Specifically, high identifiers were more willing to display organizational citizenship, had greater work satisfaction and had more pride in their work than those lower in identification. Compared with low identifiers, high identifiers were also less likely to experience burnout during the most demanding phases of a production (i.e. dress rehearsal and performance). Moreover, path analysis indicates that the effect of initial identification on the level of citizenship that was ultimately displayed was partly attributable to the role that group identification played in protecting individuals from burnout during these demanding periods. Findings thus suggest that social identification not only motivates individuals to contribute to group success but also protects them from the stressors they encounter in the process of making that contribution. Copyright © 2008 John Wiley & Sons, Ltd.
Angle random forwarding (AnRaF) for wireless sensor networks: performances and realization
Authors: Dong Fang , Qiu Peiliang , Zhang Zhaoyang
Published: July 2008

A novel random forwarding protocol for distributed wireless sensor networks (WSNs) is reported in this paper. The proposed protocol features the utilization of azimuth angle of the nodes involved and opportunistic selection of the relaying nodeviacontention among neighbors. First, the protocol with precise angle information is discussed and its multi‐hop performance is evaluated by means of both simulation and analysis in terms of average number of hops to the sink node. Simulation results show that it performs well especially in network connectivity. As a complement, node mobility is also introduced to evaluate multi‐hop performance in real environments. Then, a simple MAC scheme to ensure that the node with the highest angular advantage will be selected as a relay is proposed, and subsequently energy and latency performances based on it are evaluated. It is shown that our protocol can effectively deliver data with half number of active neighbors required in geographical random forwarding (GeRaF). Finally, a practical method is presented to estimate azimuth angle, combined with which, our forwarding protocol is shown to achieve the performance very close to the case with precise angle information. Copyright © 2008 John Wiley & Sons, Ltd.
Putting spiritual development of young people on the map: An English perspective
Authors: Green Maxine
Published: July 2008

Youth work in the United Kingdom is a profession requiring three years of training, and its beginnings are strongly rooted in a spiritual (often specifically Christian) context. Until the past few decades, spirituality was also integrated within the educational system. The author argues that intentionally bringing spirituality to the center of youth work is a return to the historical and philosophical roots of youth work, with its value on the whole person, including beliefs and values. Yet there are obstacles. For example, rising concerns to protect children from abuse eclipse efforts to extend young people's development. Youth workers also report a reluctance to address spiritual questions with young people either because of their own lack of knowledge or because they fear offending someone. Two areas that would benefit from further research and reflection in the field are how spirituality can be measured, and how a youth worker's own spiritual journey shapes and is shaped by her or his work with youth. Green reminds readers that lighthearted and playful but deeply meaningful approaches are common in many traditions.
Youth mentoring and spiritual development
Authors: Rhodes Jean E. , Chan Christian S.
Published: July 2008

Mentoring through faith‐based programs could reach some of the most severely disadvantaged youth, yet efforts could be undermined if proselytizing occurs.
Resources: Spiritual development—youth development
Authors: Longfellow Sandra P.
Published: July 2008

An annotated bibliography of this developmental intersection.
Evaluating sampling designs by computer simulation: a case study with the Missouri bladderpod
Authors: Morrison Lloyd W. , Smith David R. , Young Craig C. , Nichols Doug W.
Published: July 2008

To effectively manage rare populations, accurate monitoring data are critical. Yet many monitoring programs are initiated without careful consideration of whether chosen sampling designs will provide accurate estimates of population parameters. Obtaining accurate estimates is especially difficult when natural variability is high, or limited budgets determine that only a small fraction of the population can be sampled. The Missouri bladderpod, Lesquerella filiformis Rollins, is a federally threatened winter annual that has an aggregated distribution pattern and exhibits dramatic interannual population fluctuations. Using the simulation program SAMPLE, we evaluated five candidate sampling designs appropriate for rare populations, based on 4 years of field data: (1) simple random sampling, (2) adaptive simple random sampling, (3) grid‐based systematic sampling, (4) adaptive grid‐based systematic sampling, and (5) GIS‐based adaptive sampling. We compared the designs based on the precision of density estimates for fixed sample size, cost, and distance traveled. Sampling fraction and cost were the most important factors determining precision of density estimates, and relative design performance changed across the range of sampling fractions. Adaptive designs did not provide uniformly more precise estimates than conventional designs, in part because the spatial distribution of L. filiformis was relatively widespread within the study site. Adaptive designs tended to perform better as sampling fraction increased and when sampling costs, particularly distance traveled, were taken into account. The rate that units occupied by L. filiformis were encountered was higher for adaptive than for conventional designs. Overall, grid‐based systematic designs were more efficient and practically implemented than the others.
Community convergence in a simple microbial food web
Authors: Price Jennifer E. , Morin Peter J.
Published: July 2008

Previous studies of communities implicate many potential mechanisms that can create alternate stable states. These include density‐dependent foraging behavior, size refuges reached by early colonists, environmental feedback following disturbance, and different initial densities of intraguild predators. Previous work shows that alternate states of varying stability can occur in food webs containing the intraguild predators Blepharisma americanum and Tetrahymena vorax. Differences in colonization history could create the alternate states, consisting of dominance by either Blepharisma or Tetrahymena, but it was unclear whether results depended on effects of initial density or only on changes in the resource base. We manipulated initial densities of both species to determine if density effects alone could create alternate stable states. Convergence of these communities over time indicated that differences in initial density did not create alternate stable states. By default, other factors influenced by colonization history, such as resource availability, may produce alternate states. Models of alternate stable‐state phenomena should incorporate differences in resource availability in addition to direct competitive and predatory interactions to provide a more complete depiction of the causes of differences in community composition in otherwise similar habitats.
An Ottoman Portrait
Authors: Micklewright Nancy
Published: July 2008

This carefully composed portrait of a high-ranking Ottoman bureaucrat is striking for several reasons. First, at nearly 16 by 13 inches, it is at least four times larger than most portraits of this period and lacks the ornamental cardboard frame into which portraits were commonly placed, instead being pasted directly onto a cardboard support. Second, although there is a long tradition of documenting men at work or places of business in the photography of the late Ottoman Empire, these images tend to privilege traditional occupations (e.g., itinerant merchants or craftsmen) and sites of commerce, such as outdoor markets, the covered bazaar, or shops along the Grande Rue de Pera in Istanbul. Third and finally, in its setting, the objects chosen to be included on the desk, and the pose of the central figure, the portrait insists upon the modernity of the subject as its primary message, raising questions about its intended audience.
THE PLACE OF LOCALITY FOR IDENTITY IN THE NATION: MINORITY NARRATIVES OF COSMOPOLITAN ISTANBUL
Authors: Mills Amy
Published: July 2008

These words of an elderly Jewish man in Istanbul relate his memory of neighborhood life with Greeks, Armenians, and Muslims in the neighborhood of Kuzguncuk. In this place, there were no arguments between people of different religious backgrounds; Muslims shared “his” language, and he, as a Jew, knew Greek. As I examine his narrative for what it emphasizes and for the silences in between, I read Kuzguncuk as exceptional: describing an absence of argument in the past suggests that tension exists today; sharing multiple ethnic languages is understood now to be an old-fashioned rarity. His statement “Because we are Kuzguncuklu Jews, our Muslims over there loved us very much” suggests that in Kuzguncuk, he and his Muslim neighbors shared a common tie to place, a unique identity as Kuzguncuklu (of Kuzguncuk) that superseded any difference based on religion or ethnicity. As he describes a culture that remained from Ottoman times, his story illuminates indirectly the current Turkish national context that conditions the telling of his narrative.
FREE SPEECH IN WEBLOGISTAN? THE OFFLINE CONSEQUENCES OF ONLINE COMMUNICATION
Authors: Bucar Elizabeth M. , Fazaeli Roja
Published: July 2008

The irruption of Persian-language blogging since 2001, known to its participants as Weblogistan, has been accompanied by enthusiastic claims that weblogs are promoting previously nonexistent forms of expression, thereby rupturing traditional Iranian social, cultural, religious, and political norms. The political scientist Fereshteh Nouraie-Simone juxtaposes Weblogistan against the conditions of theocratic rule as “a public social space that allows free expression of self outside the confines of the politically manipulated physical space.” In a 2005 book, which includes translated weblog postings, Nasrin Alavi takes this line of interpretation even further, asserting that by making “it possible for young Iranians to express themselves freely and anonymously,” Weblogistan “is nothing less than a revolution within the Revolution.”
“GOD HAS CALLED ME TO BE FREE”: ALEPPAN NUNS AND THE TRANSFORMATION OF CATHOLICISM IN 18TH-CENTURY BILAD AL-SHAM
Authors: Khater Akram
Published: July 2008

On 10 June 1738 Maria Qari wrote her Catholic Melkite bishop, Athnasius Dahhan, an emphatic letter rejecting the authority of the Melkite church to impose the Eastern rite Rule of Saint Basil upon her and her fellowʿabidāt(devotees). She unequivocally states, “It is important that your Excellency knows once and for all that I will only adopt the Augustinian Rule with the Ordinances of Saint Francis de Sales. I will not become a nun under any other circumstances, for God has called me to be free from all that binds my spirit, and I will not accept any oversight [from the Melkite church] . . . Four Jesuit missionaries are in agreement with me on this point.” This is but one missive in a voluminous record of equally rancorous discourses that spanned the better part of two decades (1730–48) and entangled the ten Aleppan devotees, their Jesuit confessors and supporters, the Melkite Church, and the Vatican.
AN INTRODUCTION TO THE RESEARCH OF FARUK TABAK, SOCIOLOGIST
Authors: Salzmann Ariel
Published: July 2008

Faruk Tabak, who died of complications following a stroke on 15 February 2008 at age fifty-four, passed his youth in central Anatolia. A childhood in industrial Eskişehir—where, he once told me, the Porsuk River's color varied with the day's textile-dye batch—and college winters in smog-enveloped Ankara made him (“a man of the north”) dream of the pristine landscapes and bright tableaus of Turkey's Mediterranean shores. Trained as an architect and later as a planner at the Middle East Technical University, Tabak charted the currents of modern hegemony, capitalism, ecology, and the spatial dispersion of populations through the deep waters of the Mediterranean's past.
Perceived vocal morbidity in a problem asthma clinic
Authors: Stanton A E , Sellars C , MacKenzie K , McConnachie A , Bucknall C E
Published: July 2008

Aims:

Asthma treatment has the potential to affect patients' voices. We undertook detailed characterisation of voice morbidity in patients attending a problem asthma clinic, and we determined how patients' perceptions related to objective assessment by an experienced observer.

Methods:

Forty-three patients took part in the study. Subjects completed the self-administered voice symptom score (VoiSS) questionnaire and underwent digital voice recording. These voice recordings were scored using the grade–roughness–breathiness–asthenicity–strain system (GRBAS). Laryngoscopy was also performed.

Results:

The median VoiSS was 26 (range three to 83). VoiSS were significantly lower in the 17 patients with normal laryngeal structure and function (range four to 46; median 22), compared with the 26 patients with functional or structural laryngeal abnormality (range three to 83; median 33) (95 per cent confidence intervals for difference 0.0–21.0;p = 0.044). The overall grade score for the GRBAS scale did not differ between these two groups, and only 13 patients had a GRBAS score of one or more, recognised as indicating a voice problem. There were positive correlations between related GRBAS score and voice symptom score subscales. Although voice symptom scores were significantly more abnormal in patients with structural and functional abnormalities, this score performed only moderately well as a predictive tool (sensitivity 54 per cent; specificity 71 per cent). Nevertheless, the voice symptom score performed as well as the more labour-intensive GRBAS score (sensitivity 57 per cent; specificity 60 per cent). Patients' inhaled corticosteroid dose (median dose 1000 µg beclomethasone dipropionate or equivalent) had a statistically significant relationship with their overall grade score for the GRBAS scale (r = 0.56;p < 0.001), but not with their VoiSS. Only one patient had evidence of laryngeal candidiasis, and only two had any evidence of abnormality suggesting steroid-induced myopathy.

Conclusions:

Vocal morbidity is common in patients with asthma, and should not be immediately attributed to steroid-related candidiasis. The VoiSS merits further, prospective validation as a screening tool for ENT and/or speech and language therapy referral in patients with asthma.
Acoustic and articulatory manifestations of vowel reduction in German
Authors: Mooshammer Christine , Geng Christian
Published: July 2008

Recent phonological approaches incorporate phonetic principles in the motivation of phonological regularities, e.g. vowel reduction and neutralization in unstressed position by target undershoot. So far, evidence for this hypothesis is based on impressionistic and acoustic data but not on articulatory data. The major goal of this study is to compare formant spaces and lingual positions during the production of German vowels for combined effects of stress, accent and corrective contrast. In order to identify strategies for vowel reduction independent of speaker-specific vocal-tract anatomies and individual biomechanical properties, an approach similar to the Generalized Procrustes Analysis was applied to formant spaces and lingual vowel target positions. The data basis consists of the German stressed and unstressed full vowels /iù ɪ yù ʏ eù ɛ ɛùφùœaù a où ɔ uù ʊ/ from seven speakers recorded by means of electromagnetic midsagittal articulography (EMMA). Speaker normalized articulatory and formant spaces gave evidence for a greater degree of coarticulation with the consonant context for unstressed vowels as compared to stressed vowels. However, only for tense vowels could spatial reduction patterns be attributed to vowel shortening, whereas lax vowels were reduced without shortening. The results are discussed in the light of current theories of vowel reduction, i.e. target undershoot, Adaptive Dispersion Theory and Prominence Alignment.
Durational correlates for differentiating consonant sequences in Russian
Authors: Davidson Lisa , Roon Kevin
Published: July 2008

In Russian, the same consonant sequences are permitted in various phonotactic environments. The presence of a word boundary or reduced vowel can be phonologically contrastive, and both learners and experienced listeners may rely on fine acoustic cues to discriminate between phonotactic possibilities. In this study, durational characteristics of consonant sequences are examined to establish whether speakers use duration to distinguish (a) word-initial clusters (#C1C2), (b) consonant–schwa–consonant sequences (#C1əC2), and (c) sequences divided by a word boundary (C1#C2). Both monolingual native Russian speakers and bilingual Russian–English speakers produced several types of target sequences: stop+consonant, fricative+consonant, and nasal+consonant. Results show that C2 is significantly longer in C1#C2 than in other sequences. For #C1C2, when C1 is a stop, there is no significant difference in duration when compared with other sequence types, though C1s of other manners are significantly shorter. Differences in C1 burst duration for stops are consonant-specific, but a longer interconsonantal duration is a reliable cue to schwa presence in #C1əC2. These results are discussed with respect to their implications for gestural coordination, segmentation, and language learning.
The genusGymnogonos(Anthoathecata: Capitata: Corymorphidae)—redescription of known species and description of a new species from the North Pacific
Authors: Stepanjants S.D. , Svoboda A.
Published: July 2008

Four valid species of the genusGymnogonosare known at this point of investigations:G. crassicornis(northern Atlantic and the Arctic Seas);G. obvolutus(northern Atlantic and the Arctic Seas);G. ameriensis(circumantarctic distribution) and the new speciesG. pacificus(northern Pacific). Other species, such asCorymorpha antarctica(Pfeffer, 1889) andTubularia cingulata(Vanhöffen, 1910) from the southern hemisphere are recognized as ‘species inquirendae’. New descriptions and taxonomic discussions of the knownGymnogonosspecies have been proposed. This genus has a typical bipolar distribution in the classical meaning of this term. This genus origin may rise from tropical Corymorphidae by neoteny in the period of glacial cooling.
An investigation of periodic hypoxia at Ardbear Salt Lake
Authors: Henry Louise M. , Kennedy Robert , Keegan Brendan F.
Published: July 2008

The factors potentially leading to the development of periodic hypoxia were investigated based on field studies performed over a series of two years between November, 1997 and November, 1999. This was attempted by investigating both hard and soft seafloor. Descriptive and predictive models were developed that incorporated physical, chemical and biological data derived from the present study and previous work and were used to anticipate future possible crashes of the faunal communities due to hypoxia/anoxia. It was concluded that periodic hypoxia at Ardbear is a natural event caused by several factors to varying degrees. The results of the present study indicate that the major controlling factors for oxygen depletion are the shallow depth of the system, coupled with the development of thermal stratification during periods of calm ambient meteorological conditions of the warmer summer months. In addition, a soft, muddy bottom and highly productive plankton blooms exacerbate conditions in a system already predisposed to hypoxia.
Scale-dependent patterns of variability in species assemblages of the rocky intertidal at Helgoland (German Bight, North Sea)
Authors: Reichert Katharina , Buchholz Friedrich , Bartsch Inka , Kersten Thomas , Giménez Luis
Published: July 2008

A growing body of literature shows that benthic communities are hierarchically structured on spatial and temporal scales. In two study locations at Helgoland (North Sea), the northern and the western locations, we: (1) investigated the variation in abundance of specific algae and invertebrates at two spatial scales; and (2) evaluated the relationship between elevation and specific species at these scales. We were also interested in using this information about the spatial pattern of individual algae and invertebrates as well as the patterns of elevation to help develop a monitoring programme of the rocky intertidal. We examined the variation of individual algae and invertebrates by means of a hierarchical nested design. Data were taken from five replicates per plot, with plots located in transects (two transects per location).

At the northern location, the highest variability in cover of most algae and invertebrates occurred at the scale separated by about 50 m (scale: transect). This was a direct result of differences between the high- and the low-shore. Most species at high-shore showed a relatively low frequency of occurrence in contrast to a highest frequency of occurence (~100%) and maximal values of cover at low-shore. However, neither a linear nor a non-linear relationship between elevation and the specific species occurred. At the western location, the highest variability in most macroalgae and invertebrates investigated was among replicates (10s of centimetres apart). No relationship between elevation and individual species occurred at this location. Macroalgae at both locations were more consistent over time than invertebrate species. Our results suggest that the relevant processes shaping the individual macroalgae and invertebrates at the Helgoland rocky intertidal vary between locations and the specific species.

The potential causes of variation in macroalgal and invertebrate species at different spatial scales are discussed and suggestions for a future monitoring programme are given. Temporal inconsistency in the spatial patterns, and the fact that some individual algae and invertebrates comprising the benthic assemblages vary at different scales, speak in favour of a multiple-scale sampling approach for monitoring change in the intertidal communities at Helgoland.
The effects, costs and benefits of Salmonella control in the Danish table-egg sector
Authors: KORSGAARD H. , MADSEN M. , FELD N. C. , MYGIND J. , HALD T.
Published: July 2008

A public plan for eradicating Salmonella in Danish table-egg production was implemented in 1996. During 2002, the poultry industry took over the responsibility of the programme. The proportion of infected layer flocks was reduced from 13·4% in 1998 to 0·4% in 2006. The public-health impact of the plan has been quite marked. In 1997, 55–65% of the 5015 cases of human salmonellosis were estimated to be associated with eggs. In 2006, these figures were reduced to 1658 and 5–7%, respectively. Based on an assessment of the number of human cases attributable to table eggs, we used probabilistic modelling to estimate the avoided societal costs (health care and lost labour), and compared these with the public costs of control. The probable avoided societal costs during 1998–2002 were estimated to be 23·3 million euros (95% CI 16·3–34·9), and the results showed a continuous decreasing cost–benefit ratio reaching well below 1 in 2002. Further reductions in the primary production based on effective surveillance and control are required to ensure continued success.
Precipitation signatures of ground‐based VLF transmitters
Authors: Kulkarni P. , Inan U. S. , Bell T. F. , Bortnik J.
Published: July 2008

Numerical raytracing with Landau damping is used to calculate >100 keV electron precipitation signatures induced by hypothetical VLF transmitters distributed broadly in geomagnetic latitude and operating at a wide range of frequencies. A one‐half second pulse from each source is simulated and attenuation to the base of the magnetosphere for geomagnetic latitudes from 10° to 60° is calculated. Source location affects induced precipitation more strongly than operating frequency or radiated power. Sources located at 35° to 45° induce the most >100 keV precipitation for the 10 to 40 kHz waves typical of ground‐based VLF sources, while locations below λ ≃ 15° or above λ ≃ 55° are least effective at precipitating energetic electrons. In all cases, induced precipitation increases as the operating frequency decreases, with 10 kHz waves from a source at λ ≃ 35° the most effective at precipitating >100 keV electrons. Precipitation signatures produced by five existing ground‐based VLF transmitters are also simulated: the NAA, NLK, NAU, NPM, and NWC VLF transmitters. NWC induces the strongest >100 keV electron precipitation signature, followed by NPM, NAU, NAA, and NLK.
Bedform transport rates for the lowermost Mississippi River
Authors: Nittrouer Jeffrey A. , Allison Mead A. , Campanella Richard
Published: July 2008

New methods of data collection and processing are developed to provide quantitative, reach‐scale measurements of bedform transport mass within the tidally influenced Mississippi River. A multibeam swath profiler was used to collect daily bathymetry over a range of water discharges, and bed elevation changes induced by dune migration are measured. These values are coupled with bulk physical properties of the bed sediment to constrain mass flux, and annual bedform transport is estimated at 2.2 × 106 metric tons (MT). The total annual sand flux from the Mississippi River, calculated by combining measured bedform transport rates and suspended sediment flux, is estimated to be 20 × 106 MT. Survey data also provide information about the spatial distribution of dunes across the channel bottom. Straight reach segments are commonly mantled by dunes for the entire cross section, while bends are typically areas of focused scour devoid of bedforms. Presumably, any sediments associated with migrating dunes are propelled into suspension within bends before redepositing in the subsequent straight reach. Movement via suspension is therefore an important component for the downriver transport of bed materials in the lower Mississippi River.
Evaluation of singular Fourier coefficients in solving electromagnetic scattering by body of revolution
Authors: Tong M. S. , Chew W. C.
Published: July 2008

We develop an efficient evaluation scheme for the singular Fourier coefficients in solving electromagnetic scattering by body of revolution (BOR). For the singular modal Green's function (MGF), the scheme first evaluates the integrals over generating arc segments analytically and then distinguishes the singular part from the regular part for the integral over the angle in the revolution direction. This allows us to avoid the approximate calculation for the elliptical integral and the separated singular part is exactly evaluated in a closed form. For the singular MGF's derivatives generated from the gradient of the Green's function, we subtract the kernels with more similar singular integrands in the vicinity of singularity so that the kernels are better regularized. The procedure differs from the existent Glisson's method in several aspects and numerical experiments show that the scheme is simpler in implementation and more efficient for calculation.
Stacked uppermost mantle layers within the Slave craton of NW Canada as defined by anisotropic seismic discontinuities
Authors: Snyder David B.
Published: July 2008

A 20‐station seismic array in NW Canada recorded 336 teleseismic events with distribution in back azimuth and epicentral distance sufficient to characterize uppermost mantle discontinuities between depths typical of the Mohorovicic and Lehman discontinuities. Following wavefield decomposition, groups of seismograms were source‐normalized through simultaneous deconvolution to estimate the near‐receiver impulse response and thus detect major discontinuities beneath each seismic station. Stations within the Lac de Gras kimberlite field display an unusually strong negative impulse on the radial component within the NW quadrant and two moderate impulses on the transverse component. Forward modeling of these impulses suggests a mantle layer dipping at 22° to the southeast with a mildly anisotropic (2%) upper discontinuity at 120–135 km depth and another mildly anisotropic (2%) discontinuity at about 170 km depth. Superimposed on these layers is another, stronger anisotropic (4%) layer between 110 and 180 km depths that dips to the west. Stations outside of the Lac de Gras field, but within the southeastern Slave craton, display more numerous, but weaker, impulses. The most prominent of these occurs at about 150 km depth on the transverse component and has opposite polarity to that observed farther north. The prominent negative impulse observed on the radial component is interpreted to arise from structural‐preferred orientation in the form of a stockwork of wehrlite dykes beneath the Lac de Gras field. Interpretation of the other layers in the context of known surface geology as well as xenolith petrology and garnet geochemistry of diamondiferous kimberlites favors previous suggestions that they represent 4000–2900 Ma depleted harzburgite and eclogite layers underthrust from the northwest at 2600 or 1880 Ma. The layer beneath the SE Slave craton has a similar, but distinct, tectonic history of NW‐verging underthrusting associated with the 2635–2615 Ma Defeat Suite of plutonism. Taken together, these interpretations indicate that the Slave craton was assembled from at least four lithospheric blocks prior to its cratonization about 2580 Ma: each block is 90–120 km thick, and all four blocks abut across a steep suture boundary beneath MacKay Lake in the central Slave craton. Significant amounts of carbon and eclogites could have become incorporated into the central Slave mantle within the diamond stability field during the proposed underthrusting of lithosphere to explain their relatively common occurrence in kimberlite eruptions within the Slave craton.
Modeling the dissolved organic carbon output from a boreal mire using the convection‐dispersion equation: Importance of representing sorption
Authors: Yurova Alla , Sirin Andrey , Buffam Ishi , Bishop Kevin , Laudon Hjalmar
Published: July 2008

In this paper we present a model of the dissolved organic carbon (DOC) concentrations and fluxes in mire water based on the convection‐dispersion equation. The dynamics of sorbed, potentially soluble organic carbon (SPSOC) in the peat matrix are simulated in parallel with DOC. First, the model is applied solely to stagnant water conditions in order to interpret the results of laboratory peat incubations, with the focus on sorption processes. Some important model parameters are derived using literature data complemented by information from new incubation experiments. Second, the model is fully applied to simulate the DOC concentrations in the outlet of a steam draining a small headwater mire in northern Sweden during the period 1993–2001. A relatively good model fit (mean bias error (MBE) = −0.6–2.2 mg L−1, Willmott index of agreement d > 0.7 for the daily concentrations) was found for all the categories of stream discharge, except periods with very low flow (q < 0.3 mm d−1). When seeking explanations for the interannual variability in DOC concentrations, we, like previous authors, could find the influence of temperature, flow path, and intensity. However, the model has helped to demonstrate that the system also has a “memory”: the store of sorbed, potentially soluble organic carbon in a year affects the DOC concentrations and fluxes in the following year.
Mantle‐wide sequestration of carbon in silicates and the structure of magnesite II
Authors: Panero Wendy R. , Kabbes Jason E.
Published: July 2008

The participation of the deep mantle in the global carbon cycle and its ability to sequester carbon over billion‐year time scales depends upon the mineralogical host for carbon. Density‐functional theory calculations for MgCO3‐magnesite and structures with tetrahedrally coordinated carbon reveal the stability of magnesite up to ∼80 GPa, with a bulk modulus of 110 (±2) GPa. Magnesite undergoes a structural transition to a pyroxene‐like structure at ∼80–100 GPa, with a density increase of 4.5–7.1%. Combined with thermodynamic models for the MgSiO3—MgCO3 system, the inter‐solubility of MgCO3 with MgSiO3 orthoenstatite and perovskite constrains the carbon content in the silicates to an upper bound of 4 and 20 ppm (wt), respectively. The carbon content in lower mantle silicates is estimated to be no more than 1% of the mantle's total carbon budget for degassed regions, such that in even the mantle's most depleted regions, most carbon must be stored in carbonates or diamond.
Dual‐Doppler lidar observation of horizontal convective rolls and near‐surface streaks
Authors: Iwai Hironori , Ishii Shoken , Tsunematsu Nobumitsu , Mizutani Kohei , Murayama Yasuhiro , Itabe Toshikazu , Yamada Izumi , Matayoshi Naoki , Matsushima Dai , Weiming Sha , Yamazaki Takeshi , Iwasaki Toshiki
Published: July 2008

Dual‐Doppler lidar and heliborne sensors were used to investigate the three‐dimensional (3D) structure of the wind field over Sendai Airport in June 2007. The 3D structures of several‐hundred‐meter‐scale horizontal convective rolls (HCRs) in the sea‐breeze layer were observed by the dual‐Doppler lidar. The scale of the HCRs determined by the heliborne sensors roughly agreed with that determined by the dual‐Doppler lidar. Analysis of the dual‐Doppler lidar data showed that the region of upward flow in the HCRs originated in near‐surface low‐speed streaks. This structure is consistent with the results of large‐eddy simulations of the atmospheric boundary layer. The aspect ratios of the HCRs were close to those predicted by linear theories.
Solar modulation of Northern Hemisphere winter blocking
Authors: Barriopedro David , García‐Herrera Ricardo , Huth Radan
Published: July 2008

The blocking response to the 11‐year solar cycle is investigated for 44 winters (1955–1999) and stratified according to the level of solar activity and the phase of the Quasi‐Biennial Oscillation (QBO). Several blocking features are modulated by solar activity, irrespective of the QBO phase, but the responses amplify under the QBO‐west phases. Solar activity modulates the preferred locations for blocking occurrence over both Oceans, causing local frequency responses therein. Over the Pacific Ocean high/low solar activity induces an enhanced blocking activity over its eastern/western part. Atlantic blocking occurrence increases for both (high/low) solar phases, with a spatial dependent response confined to western/eastern Atlantic. Although solar effects are negligible in blocking frequency for the entire Atlantic sector, other blocking features exhibit significant responses. Low solar Atlantic blocking episodes last longer, are located further east and become more intense than high solar blocking events. The implications of these solar‐related changes are discussed. Our results suggest that the excessively cold conditions recorded in Europe during the Maunder Minimum may have arisen from an eastward shift of long‐lasting blockings with near‐normal frequencies.
Sandy bottom communities at the end of a cold (1971-1975) and warm (1997-1998) regime in the California Current: impacts of high and low plankton production
Authors: Oliver John , Kim Stacy , Slattery Peter , Oakden James , Hammerstrom Kamille , Barnes Ethan
Published: July 2008

There were highly significant changes in the structure of benthic infaunal communities at the end of the last cold regime (1976) compared to the end of the last warm regime (1999) in the California Current. The warm regime is characterized by much lower plankton production, which we argue is the primary cause of the degraded infaunal community at the end of the warm regime. In 1997-98, we resampled a depth gradient along a subtidal, high-energy sandy beach (6-24m) in Monterey Bay that was sampled for five years at the end of the last cold regime (1971-75). There was a dramatic decline in the total number species, number of individuals, and biomass by the end of the warm period. There was no overlap in benthic assemblages at all water depths between the decades in either non-metric multidimensional scaling ordination or cluster analysis. In the 1970s, the community dominants in the shallow crustacean zone, centered in 9 m, were pericarid crustaceans, including predacious phoxocephilid amphipods, haustoriid amphipods, and ostracods, which all live in the sediment. The amphipods, in particular, are well adapted to burrowing in sand. The numerical dominants in the deeper polychaete zone (18-24m) were large, sedentary polychaete worms. The largest was a tube-dwelling predator (Nothria) accounting for most of the biomass. The other was a suspension and surface deposit feeding polychaete worm, Magelona. By the 1990s, the most abundant crustacean was a small, swimming amphipod; and the most abundant polychaetes were small, relatively mobile, and deposit feeding. This trend from large size, sedentary, and suspension feeding to smaller size, higher mobility, and deposit feeding also characterizes infaunal shifts from the food-rich continental shelf into the food-poor deep sea. The dominant polychaetes had more opportunistic life histories, and shallow faunal zones extended into deeper water in the 1990s. If global warming continues, the ongoing cold regime may be less productive and the sandy bottom communities should not develop the species composition and high diversity, abundance, and biomass observed in the 1970s.
Regulation of the RelA (p65) transactivation domain
Authors: O'shea John M. , Perkins Neil D.
Published: July 2008

The RelA (p65) NF-κB (nuclear factor κB) subunit contains an extremely active C-terminal transcriptional activation domain, required for its cellular function. In the present article, we review our knowledge of this domain, its modifications and its known interacting proteins. Moreover, we discuss how analysis of its evolutionary conservation reveals distinct subdomains and conserved residues that might give insights into its regulation and function.
The DEAD box RNA helicases p68 (Ddx5) and p72 (Ddx17): novel transcriptional co-regulators
Authors: Fuller-Pace Frances V. , Ali Simak
Published: July 2008

DEAD box [a motif named after its amino acid sequence (Asp-Glu-Ala-Asp)] RNA helicases are known to play key roles in all cellular processes that require modulation of RNA structure. However, in recent years, several of these proteins have been found to function in transcriptional regulation. In the present paper, we shall review the literature demonstrating the action of p68 and, where data are available, p72 as transcriptional co-regulators for a range of transcription factors, namely ERα (oestrogen receptor α), the tumour suppressor p53, the myogenic regulator MyoD and Runx2, a transcription factor essential for osteoblast development. We shall also discuss evidence indicating that, in some cases at least, p68 and p72 have distinct, non-redundant, roles.
Structure and function of ribosomal RNA gene chromatin
Authors: Birch Joanna L. , Zomerdijk Joost C.B.M.
Published: July 2008

Transcription of the major ribosomal RNAs by Pol I (RNA polymerase I) is a key determinant of ribosome biogenesis, driving cell growth and proliferation in eukaryotes. Hundreds of copies of rRNA genes are present in each cell, and there is evidence that the cellular control of Pol I transcription involves adjustments to the number of rRNA genes actively engaged in transcription, as well as to the rate of transcription from each active gene. Chromatin structure is inextricably linked to rRNA gene activity, and the present review highlights recent advances in this area.
Polypyrimidine-tract-binding protein: a multifunctional RNA-binding protein
Authors: Sawicka Kirsty , Bushell Martin , Spriggs Keith A. , Willis Anne E.
Published: July 2008

PTB (polypyrimidine-tract-binding protein) is a ubiquitous RNA-binding protein. It was originally identified as a protein with a role in splicing but it is now known to function in a large number of diverse cellular processes including polyadenylation, mRNA stability and translation initiation. Specificity of PTB function is achieved by a combination of changes in the cellular localization of this protein (its ability to shuttle from the nucleus to the cytoplasm is tightly controlled) and its interaction with additional proteins. These differences in location and trans-acting factor requirements account for the fact that PTB acts both as a suppressor of splicing and an activator of translation. In the latter case, the role of PTB in translation has been studied extensively and it appears that this protein is required for an alternative form of translation initiation that is mediated by a large RNA structural element termed an IRES (internal ribosome entry site) that allows the synthesis of picornaviral proteins and cellular proteins that function to control cell growth and cell death. In the present review, we discuss how PTB regulates these disparate processes.
Mechanism of ribosomal subunit joining during eukaryotic translation initiation
Authors: Acker Michael G. , Lorsch Jon R.
Published: July 2008

Decades of research have yielded significant insight into the mechanism by which a cell translates an mRNA into the encoded protein. However many of the molecular details of the process remain a mystery. Translation initiation is an important control point in gene expression, and misregulation can lead to diseases such as cancer. A better understanding of the mechanism of translation initiation is imperative for the development of novel therapeutic agents. Recently, a combination of genetic, biochemical and biophysical studies has begun to shed light on how, at a molecular level, the translational machinery initiates protein synthesis. In the present review, we briefly compare and contrast the initiation pathways utilized by bacteria, archaea and eukaryotes, and then focus on translation initiation in eukaryotes and recent advances in our understanding of the subunit joining step of the process.