bluuebunny/crossref_metadata_2025 huggingface dataset:
Repression and Repressors
Authors: Derakshan Nazanin , Eysenck Michael W.
Published: January 2007

The present article reviews and evaluates the history of theory and research on the concept of repression and, its personality characteristic, the repressive coping style. The four-factor theory ( Eyseneck, 1997 ), a comprehensive cognitive theory of repressors, attempts to provide evidence for the avoidant or defensive cognitive processors allegedly underlying repression. According to the four-factor theory, individuals with a repressive coping style (repressors) possess opposite cognitive biases for both external and internal stimuli. In other words, they avoid attending to, and tend to interpret, four sources of information — environmental stimuli, their own physiological activity, their own behavior, and information stored in long term memory — in a nonthreatening fashion. Some evidence consistent with these predictions is discussed. Also, the four-factor theory attempts to account for some failures of concordance among the self-report, behavioral, physiological, measures of anxiety found in repressors.
Cognitive Style
Authors: Tullett Arthur D.
Published: January 2007

Many authors have drawn attention to the differences in psychosocial variables which exist between national cultures. This paper investigates Prato Previde's (1991) hypothesis that Adaptive-Innovative (A-I) cognitive style is a stable cognitive process within the individual which is largely uninfluenced by national culture. Empirical findings and statistical analyses are brought together from a range of studies in different countries to test this hypothesis. In all, the conclusion is drawn that the data are largely consistent with this hypothesis. The principal factors supporting this conclusion comprise: (1) the similarity between the psychometric properties and factor structures obtained for each of the current five language versions (English, French, Dutch, Italian, and Slovak) of the KAI — the measure of (A-I) cognitive style; and (2) the evidence that A-I cognitive style varies more by occupation and by work function than by nation.
Modeling the effects of cold‐dense and hot‐tenuous plasma sheet on proton ring current energy and peak location
Authors: Lavraud Benoit , Jordanova Vania K.
Published: January 2007

We have run kinetic ring current simulations with different plasma boundary conditions, but preserving a constant plasma pressure, during a “test” time interval conducive to a storm. Although the energy density of the injected plasma is kept constant, the resulting proton ring current energy is significantly increased as the injected plasma is colder and denser. Investigation of the separate effects of density and temperature shows that (1) ring current strength is primarily controlled by density, and that (2) colder plasma leads to a ring current peak closer to Earth and to midnight, but density has no effect. While cold plasma may convect deeper inside the ring current region, hotter plasma is more subject to magnetic drifts and quickly drifts toward dusk with lower energization. These results support the idea that the presence of cold and dense plasma in the magnetotail may lead to increased ring current during an ensuing storm.
Oceanic heat transport onto the Amundsen Sea shelf through a submarine glacial trough
Authors: Walker Dziga P. , Brandon Mark A. , Jenkins Adrian , Allen John T. , Dowdeswell Julian A. , Evans Jeff
Published: January 2007

Glaciers which drain the West Antarctic Ice Sheet (WAIS) into the Amundsen Sea are accelerating and thinning rapidly. These observations have been attributed to the regional oceanography whereby heat contained within Circumpolar Deep Water (CDW) drives the basal melting of floating glaciers. On the basis of new data we calculate that 2.8 terra‐Watts (1012) of oceanic heat flow onto the continental shelf and toward the glaciers via a submarine glacial trough. This is enough to account for most of the basal melting in the entire region suggesting the ocean is supplying an excess of heat toward the Antarctic continent.
Effect of Alpine glaciation on thermochronometer age‐elevation profiles
Authors: Densmore Mathew S. , Ehlers Todd A. , Woodsworth Glenn J.
Published: January 2007

Low‐temperature thermochronometers are widely used to quantify exhumation histories, typically by interpreting sample cooling age‐elevation relationships. However, the effects of specific geomorphic processes on age‐elevation profiles are seldom considered. We integrate apatite (U‐Th)/He [AHe], apatite fission track, and zircon (U‐Th)/He thermochronometry with numerical modeling to determine the effect of glacial erosion on an age‐elevation profile from the heavily glaciated southern Coast Mountains, British Columbia. AHe data show a distinct break in slope in age‐elevation between 1900–2100 m. We interpret this break in slope as an acceleration of erosion associated with the onset of alpine glaciation. We use a 3‐D thermo‐kinematic model to constrain pre‐ and synglacial erosion rates. Results indicate a preglacial erosion rate of ∼0.4 mm/yr that accelerated by a factor of ∼2 since ∼6 Ma. We propose that glacial valley widening and deepening are responsible for the observed nonlinear AHe age‐elevation profile.
Atlantic warm pool, Caribbean low‐level jet, and their potential impact on Atlantic hurricanes
Authors: Wang Chunzai , Lee Sang‐ki
Published: January 2007

The Atlantic Warm Pool (AWP) is a large body of warm water (warmer than 28.5°C) that appears in the Gulf of Mexico, the Caribbean Sea, and the western tropical North Atlantic during the summer and fall. Located to its northeastern side is the North Atlantic Subtropical High (NASH) that produces the easterly trade winds in the tropics. The trade winds carry moisture from the tropical North Atlantic into the Caribbean Sea where the flow intensifies forming the Caribbean Low‐Level Jet (CLLJ). This paper finds that the easterly CLLJ is maximized in the summer and winter, whereas it is minimized in the fall and spring. The semi‐annual feature of the CLLJ results from the semi‐annual variation of sea level pressure in the Caribbean region associated with the east‐west excursion of the NASH. The AWP's impact is to weaken the summertime NASH, especially at its southwestern edge and thus weaken the easterly CLLJ. The weakening of the easterly CLLJ, in conjunction with the AWP‐induced change of upper‐level wind, reduces the tropospheric vertical wind shear that favors hurricane formation and intensification during August–October.
Inhibition of apoptosis induced by heat shock preconditioning is associated with decreased phagocytosis in human polymorphonuclear leukocytes through inhibition of Rac and Cdc42
Authors: Selva Eric , Brest Patrick , Loubat Agnès , Lassalle Sandra , Auberger Patrick , Hofman Paul
Published: January 2007

The functionality of polymorphonuclear leukocytes (PMNL) and the exact process of the protective program employed by these cells in response to the heat shock (HS) remain ill‐defined and debated. Particularly, the mechanism of phagocytic impairment induced by the HS and the molecular events associated with the delay of apoptosis used by these cells in such condition have given conflictual data. The aim of the present work is to study the consequences of the HS in different pathways involved in human PMNL apoptosis and subsequently in human PMNL phagocytic function. We demonstrated that HS (41°C, 1 h) preconditioning induced inhibition of spontaneous PMNL apoptosis observed at 18 h in control cells incubated at 37°C. This inhibition was characterized by absence of morphological nuclear changes, decrease of DNA fragmentation, low level of annexin V expression and decrease of caspase‐3 activity. In parallel, HS increased both Hsp70 and Mcl‐1 protein levels in PMNL. Phagocytosis of latex beads by PMNL was inhibited by HS (41°C, 1 h) preconditioning despite an upregulation of CD11b, CD16 and CD47. Moreover, HS induced prolonged F actin depolymerization and inhibited both Rac and Cdc42 activation in PMNL. Finally, our results identify a new function of Mcl‐1 in HS protection against apoptosis.
Evidence for Inbreeding Depression in the Food‐Deceptive Colour‐Dimorphic Orchid Dactylorhiza sambucina (L.) Soò
Authors: Juillet N. , Dunand‐Martin S. , Gigord L. D. B.
Published: January 2007

Abstract: About one third of all orchid species are deceptive, i.e., not providing any reward to their pollinator. Such species often have lower visitation rates compared to rewarding relatives. This could result in lower levels of geitonogamous selfing and thus would provide an advantage in term of progeny fitness through inbreeding avoidance. This hypothesis could be tested by comparing the level of inbreeding depression between deceptive and rewarding orchids. However, due to the difficulty to raise orchids from seeds, few studies of inbreeding depression are available, and most are focused on very early life stages, such as seed mass or embryo viability. Here, we present the results from an experimental investigation of inbreeding depression in the deceptive flower‐colour dimorphic Dactylorhiza sambucina, from in vitro cultivation to greenhouse soil transplantation. We found strong inbreeding depression at all recorded stages (i.e., germination and survival), with estimates ranging from 0.47 to 0.75. Our study finally proposes a simple and suitable experimental protocol to raise orchids from seeds with high germination rates.
Subcellular Effects of Drought Stress in Rosmarinus officinalis
Authors: Olmos E. , Sánchez‐Blanco M. J. , Ferrández T. , Alarcón J. J.
Published: January 2007

Abstract: The use of Rosmarinus officinalis, and other wild plant species, in the Mediterranean area is an interesting solution in order to avoid the desertification and rapid soil erosion, because of their good resistance to environmental conditions. Previous articles have described experiments designed to determine the impact of water stress at the plant level in this species, but more knowledge is required at the subcellular and ultrastructural levels. An anatomic and ultrastructural study of the leaves was conducted on Rosmarinus officinalis plants growing under different water treatments. In the leaves of water‐stressed plants, the leaf water potential and turgor decreased, and leaf osmotic potential became more negative with respect to control plants. The anatomic investigations showed that both the mesophyll intercellular spaces and the epidermal cell size were reduced significantly under the more intense drought stress conditions. At the subcellular level, chloroplasts accumulated plastoglobuli and lipid bodies, and cuticle thickness was increased under water stress. In our experiment, the anatomic and ultrastructural modifications of Rosmarinus officinalis could be considered an additional adaptation to drought stress together with physiological and biochemical modifications as antioxidant accumulation.
Variation in Defence Strategies in Two Species of the Genus Beilschmiedia under Differing Soil Nutrient and Rainfall Conditions
Authors: Simon J. , Miller R. E. , Woodrow I. E.
Published: January 2007

Abstract: The relationships between various leaf functional traits that are important in plant growth (e.g., specific leaf area) have been investigated in recent studies; however, research in this context on plants that are highly protected by chemical defences, particularly resource‐demanding nitrogen‐based defence, is lacking. We collected leaves from cyanogenic (N‐defended) Beilschmiedia collina B. Hyland and acyanogenic (C‐defended) Beilschmiedia tooram (F. M. Bailey) B. Hyland at high‐ and low‐soil nutrient sites in two consecutive years that varied significantly in rainfall. We then measured the relationships between chemical defence and morphological and functional leaf traits under the different environmental conditions. We found that the two species differed significantly in their resource allocation to defence as well as leaf morphology and function. The N defended species had a higher leaf nitrogen concentration, whereas the C‐defended species had higher amounts of C‐based chemical defences (i.e., total phenolics and condensed tannins). The C‐defended species also tended to have higher force to fracture and increased leaf toughness. In B. collina, cyanogenic glycoside concentration was higher with higher rainfall, but not with higher soil nutrients. Total phenolic concentration was higher at the high soil nutrient site in B. tooram, but lower in B. collina; however, with higher rainfall an increase was found in B. tooram, while phenolics decreased in B. collina. Condensed tannin concentration decreased in both species with rainfall and nutrient availability. We conclude that chemical defence is correlated with leaf functional traits and that variation in environmental resources affects this correlation.
Growth Rates, Reproductive Phenology, and Pollination Ecology of Espeletia grandiflora (Asteraceae), a Giant Andean Caulescent Rosette
Authors: Fagua J. C. , Gonzalez V. H.
Published: January 2007

Abstract: From March 2001 to December 2002, we studied the reproductive phenology, pollination ecology, and growth rates of Espeletia grandiflora Humb. and Bonpl. (Asteraceae), a giant caulescent rosette from the Páramos of the Eastern Andes of Colombia. Espeletia grandiflora was found to be predominantly allogamous and strongly self‐incompatible. Bumblebees (Bombus rubicundus and B. funebris) were the major pollinators of E. grandiflora, although moths, hummingbirds, flies, and beetles also visited flowers. Inflorescence development began in March and continued through August to September. Plants flowered for 30 ‐ 96 days with a peak from the beginning of October through November. The percentage of flowering plants strongly differed among size classes and between both years. Seed dispersal occurred as early as September through May of the following year. The average absolute growth rate for juveniles and adults rate was 7.6 cm/year. Given the scarcity of floral visitors at high altitudes due to climatic conditions, we suggest that even small contributions from a wide range of pollinators might be advantageous for pollination of E. grandiflora. Long‐term studies on different populations of E. grandiflora are required to determine if the high growth rates are representative, to quantify the variation in the flowering behavior within and among populations, and to establish if nocturnal pollination is a trait that is exclusive to our population of E. grandiflora.
Optimal control of molecular alignment in dissipative media
Authors: Pelzer Adam , Ramakrishna S. , Seideman Tamar
Published: January 2007

We explore the controllability of nonadiabatic alignment in dissipative media, and the information content of control experiments regarding the bath properties and the bath system interactions. Our approach is based on a solution of the quantum Liouville equation within the multilevel Bloch formalism, assuming Markovian dynamics. We find that the time and energy characteristics of the laser fields that produce desired alignment characteristics at a predetermined instant respond in distinct manners to decoherence and to population relaxation, and are sensitive to both time scales. In particular, the time-evolving spectral composition of the optimal pulse mirrors the time-evolving rotational composition of the wave packet, and points to different mechanisms of rotational excitation in isolated systems, in systems subject to a decoherering bath, and in ones subject to a population relaxing bath.
Mechanism of hydrogen bond assisted cis-trans isomerization in the excited state of 2-naphthol
Authors: Niehaus Thomas A.
Published: January 2007

Stationary points on the ground and first two excited state potential energy surfaces of 2-naphthol and the hydrogen bonded complex 2-naphthol∙NH3 have been located using an approximate method (time dependent density functional based tight-binding) based on time dependent density functional theory (TDDFT). For the obtained extrema, single point calculations at the full TDDFT level (PW91∕6-311+G**) were performed for validation purposes. The energetical ordering of the cis and trans forms of 2-naphthol in the different electronic states is found to be in good agreement with available experimental data. Interestingly, also the optical spectrum is correctly predicted by TDDFT in contrast to calculations on unsubstituted acenes in the literature. Besides the stationary points, also the minimum energy paths connecting them are calculated using an adaptive nudged elastic band approach in order to estimate isomerization barriers. While the increase of barrier height going from the ground to the first excited state is already documented, the authors find as a new result a significant barrier reduction upon hydrogen bond formation in the S2. The observed effect can contribute to the explanation of recent experiments on infrared laser induced cis-trans isomerization in 2-naphthol.
Competing spin-dependent conductance channels in underoxidized tunnel junctions
Authors: Ventura J. , Araujo J. P. , Sousa J. B. , Ferreira R. , Freitas P. P.
Published: January 2007

The authors study the transport properties of magnetic tunnel junctions (MTJs) with underoxidized 9Å AlOx barriers suitable for magnetoresistive sensors in high-density storage devices. Temperature dependent measurements revealed different dominant transport mechanisms in different junctions: tunnel, metallic, or both, depending on the MTJ-magnetic state. This denotes a competition between two conductance channels (tunnel through oxidized AlOx and metallic through unoxidized Al nanoconstrictions), so that the dominance of one over the other is the outcome of small structural and composition variations in the barrier. Furthermore, transport through the Al nanobridges is spin dependent, caused by ballistic and/or diffusive magnetoresistance through nonmagnetic metallic paths.
Enhanced luminescence from catalyst-free grown InP nanowires
Authors: Mattila M. , Hakkarainen T. , Lipsanen H. , Jiang H. , Kauppinen E. I.
Published: January 2007

The surface effects in the optical properties of catalyst-free grown InP nanowires are investigated. Both as-grown nanowires and nanowires treated with hydrofluoric acid are studied using low- and room-temperature continuous-wave and time-resolved photoluminescence measurements and transmission electron microscopy. It is shown that the room-temperature photoluminescence intensity is increased by two orders of magnitude after the surface treatment, and that there is also a significant increase in the double-exponential photoluminescence decay time.
The effect of silicon doping in the selected barrier on the electroluminescence of InGaN∕GaN multiquantum well light emitting diode
Authors: Park Eun-Hyun , Kang David Nicol Hun , Ferguson Ian T. , Park Soo-Kun Jeon Joong-Seo , Yoo Tae-Kyung
Published: January 2007

The effect of silicon doping in the selected barrier on the electroluminescence of InGaN∕GaN multiquantum well light emitting diode (LED) was studied using dual wavelength LEDs. The result verified that the hole carrier transport is easily blocked by the silicon doped barrier, and the dominant electron and hole recombination occurs at the wells between p-GaN and the silicon doped barrier. The electroluminescence spectrum and the wavelength blueshift of the silicon doped LEDs were compared with undoped LEDs. The numerical simulation was done to clearly explain the hole blocking effect by the silicon doped barrier.
Dynamic nuclear polarization induced by hot electrons
Authors: Komori Yosuke , Okamoto Tohru
Published: January 2007

A method for local dynamic nuclear polarization is demonstrated in a GaAs∕AlGaAs heterostructure at the Landau level filling factor ν=3. Using a narrow channel sample, where the width varies stepwise along the electron flow, the authors find that electron cooling (heating) causes the polarization of nuclear spins against (toward) the external magnetic field at liquid helium temperatures. The longitudinal nuclear spin relaxation rate varies exponentially with inverse temperature.
Consideration of switching mechanism of binary metal oxide resistive junctions using a thermal reaction model
Authors: Sato Yoshihiro , Kinoshita Kentaro , Aoki Masaki , Sugiyama Yoshihiro
Published: January 2007

The authors investigated the resistive switching of transition metal oxide (TMO) junctions by applying a short voltage pulse and found that the response time of the “reset” process was dependent on the resistance in the low resistive state. By using a thermal conductive equation to calculate the temperature of the filamentary conductive path in the TMO film, the temperature in the reset process was estimated to reach the same temperature grade in each reset. On this basis, the previous experimental relation is well explained by assuming a general thermal chemical reaction model for the reset process.
Amorphous states of melt-spun alloys in the system Dy–(Mn,Fe)6–(Ge,Al)6
Authors: Kerschl P. , Rößler U. K. , Gemming T. , Müller K.-H. , Śniadecki Z. , Idzikowski B.
Published: January 2007

Amorphous states have been found in rapidly quenched alloys in the pseudoternary system DyMn6−x−yFex+yGe6−xAlx (x,y=0 to 6). The amorphous state is formed in competition to the crystallization of ternary (1-6-6 rare earth-transition metal-metal) compounds. The melt-spun ribbons were investigated by x-ray diffraction, high resolution transmission electron microscopy, differential scanning calorimetry, and magnetization measurements. All amorphous samples exhibit multistep crystallization behavior without a clear indication for a glass transition below the first exothermic effect. Some of the amorphous alloys exhibit a magnetic ordering above room temperature and complex magnetic transitions similar to the properties of crystalline 1-6-6 compounds.
Heavy metal tolerance in common fern species
Authors: Kachenko Anthony G. , Singh Balwant , Bhatia Naveen P.
Published: January 2007

The effects of cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb) and zinc (Zn) on the growth and uptake of 10 fern species was investigated under a controlled environment in order to evaluate their suitability for phytoremediation. Fern species included Adiantum aethiopicum, Blechnum cartilagineum, Blechnum nudum, Calochlaena dubia, Dennstaedtia davallioides, Doodia aspera, Hypolepis muelleri, Nephrolepis cordifolia, Pellaea falcata and the arsenic (As) hyperaccumulating Pteris vittata. Ferns were exposed to four levels of metals at concentrations of 0, 50, 100 and 500 mg kg–1 for a period of 20 weeks. The response of ferns significantly varied among species and metals. In general, heavy-metal translocation was limited, with metals being absorbed and held in roots, suggesting an exclusion mechanism as part of the ferns’ tolerance to the applied metals. Similar metal-accumulation patterns were observed for all species in that accumulation generally increased with increasing metal treatments; in most cases a sharp increase in metal accumulation was observed between 100 and 500 mg kg–1 treatments, suggesting a breakdown in tolerance mechanisms and unrestricted metal transport. This was corroborated by enhanced visual toxicity symptoms and a reduction in survival rates among ferns when exposed to 500 mg kg–1 metal treatments; and to a lesser extent 100 mg kg–1 metal treatments. Of the species investigated, N. cordifolia and H. muelleri were identified as possible candidates in phytostabilisation of Cu, Pb, Ni or Zn contaminated soils. Similarly, D. davallioides appeared favourable for use in phytostabilisation of Cu and Zn contaminated soils. These species had high survival rates and accumulated high levels of the aforementioned metals relative to other ferns investigated. Ferns belonging to the family Blechnaceae (B. nudum, B. cartilagineum and D. aspera) and C. dubia (Family Dicksoniaceae) were least tolerant to most metals, had a low survival rate and were classified as being unsuitable for phytoremediation purposes. Metal tolerance was also observed in P. vittata when exposed to Cd, Cr and Cu; however, no hyperaccumulation was observed.
Structure of the monooxygenase component of a two-component flavoprotein monooxygenase
Authors: Alfieri Andrea , Fersini Francesco , Ruangchan Nantidaporn , Prongjit Methinee , Chaiyen Pimchai , Mattevi Andrea
Published: January 2007

p
-Hydroxyphenylacetate hydroxylase from
Acinetobacter baumannii
is a two-component system consisting of a NADH-dependent FMN reductase and a monooxygenase (C
2
) that uses reduced FMN as substrate. The crystal structures of C
2
in the ligand-free and substrate-bound forms reveal a preorganized pocket that binds reduced FMN without large conformational changes. The Phe-266 side chain swings out to provide the space for binding
p
-hydroxyphenylacetate that is oriented orthogonal to the flavin ring. The geometry of the substrate-binding site of C
2
is significantly different from that of
p
-hydroxybenzoate hydroxylase, a single-component flavoenzyme that catalyzes a similar reaction. The C
2
overall structure resembles the folding of medium-chain acyl-CoA dehydrogenase. An outstanding feature in the C
2
structure is a cavity located in front of reduced FMN; it has a spherical shape with a 1.9-Å radius and a 29-Å
3
volume and is interposed between the flavin C4a atom and the substrate atom to be hydroxylated. The shape and position of this cavity are perfectly fit for housing the oxygen atoms of the flavin C4a-hydroperoxide intermediate that is formed upon reaction of the C
2
-bound reduced flavin with molecular oxygen. The side chain of His-396 is predicted to act as a hydrogen-bond donor to the oxygen atoms of the intermediate. This architecture promotes the nucleophilic attack of the substrate onto the terminal oxygen of the hydroperoxyflavin. Comparative analysis with the structures of other flavoenzymes indicates that a distinctive feature of monooxygenases is the presence of specific cavities that encapsulate and stabilize the crucial hydroperoxyflavin intermediate.
Cdc42 GTPase-activating protein deficiency promotes genomic instability and premature aging-like phenotypes
Authors: Wang Lei , Yang Linda , Debidda Marcella , Witte David , Zheng Yi
Published: January 2007

Cdc42 is a member of the Rho GTPase family known to regulate cell actin cytoskeleton organization, polarity, and growth, but its function in mammalian organismal physiology remains unclear. We found that natural aging of WT mice is marked with increased Cdc42 activity in various tissues. Among the negative regulators of Cdc42, gene targeting of Cdc42 GTPase-activating protein (Cdc42GAP) results in constitutively elevated Cdc42-GTP level in diverse tissues of adult mice; significantly shortened life span of the animals; and multiple premature aging-like phenotypes, including a reduction in body mass, a loss of subdermal adipose tissue, severe lordokyphosis, muscle atrophy, osteoporosis, and reduction of reepithelialization ability in wound-healing. Cdc42GAP
−/−
mouse embryonic fibroblasts and/or tissues display reduced population doubling, significantly dampened DNA damage repair activity after DNA-damaging agent treatment, accumulated genomic abnormalities, and induction of p53, p16
Ink4a
, p21
Cip1
, and senescence-associated β-galactosidase expressions. Furthermore, Cdc42 activation is sufficient to promote a premature cellular senescence phenotype that depends on p53. These results suggest a role of Cdc42 activity in regulating mammalian genomic stability and aging-related physiology.
Explicit off-line criteria for stable accurate time filtering of strongly unstable spatially extended systems
Authors: Majda Andrew J. , Grote Marcus J.
Published: January 2007

Many contemporary problems in science involve making predictions based on partial observation of extremely complicated spatially extended systems with many degrees of freedom and physical instabilities on both large and small scales. Various new ensemble filtering strategies have been developed recently for these applications, and new mathematical issues arise. Here, explicit off-line test criteria for stable accurate discrete filtering are developed for use in the above context and mimic the classical stability analysis for finite difference schemes. First, constant coefficient partial differential equations, which are randomly forced and damped to mimic mesh scale energy spectra in the above problems are developed as off-line filtering test problems. Then mathematical analysis is used to show that under natural suitable hypothesis the time filtering algorithms for general finite difference discrete approximations to ans×spartial differential equation system with suitable observations decompose into much simpler independents-dimensional filtering problems for each spatial wave number separately; in other test problems, such block diagonal models rigorously provide upper and lower bounds on the filtering algorithm. In this fashion, elementary off-line filtering criteria can be developed for complex spatially extended systems. The theory is illustrated for time filters by using both unstable and implicit difference scheme approximations to the stochastically forced heat equation where the combined effects of filter stability and model error are analyzed through the simpler off-line criteria.
Desmoplakin: an unexpected regulator of microtubule organization in the epidermis
Authors: Lechler Terry , Fuchs Elaine
Published: January 2007

Despite their importance in cell shape and polarity generation, the organization of microtubules in differentiated cells and tissues remains relatively unexplored in mammals. We generated transgenic mice in which the epidermis expresses a fluorescently labeled microtubule-binding protein and show that in epidermis and in cultured keratinocytes, microtubules stereotypically reorganize as they differentiate. In basal cells, microtubules form a cytoplasmic network emanating from an apical centrosome. In suprabasal cells, microtubules concentrate at cell–cell junctions. The centrosome retains its ability to nucleate microtubules in differentiated cells, but no longer anchors them. During epidermal differentiation, ninein, which is a centrosomal protein required for microtubule anchoring (Dammermann, A., and A. Merdes. 2002. J. Cell Biol. 159:255–266; Delgehyr, N., J. Sillibourne, and M. Bornens. 2005. J. Cell Sci. 118:1565–1575; Mogensen, M.M., A. Malik, M. Piel, V. Bouckson-Castaing, and M. Bornens. 2000. J. Cell Sci. 113:3013–3023), is lost from the centrosome and is recruited to desmosomes by desmoplakin (DP). Loss of DP prevents accumulation of cortical microtubules in vivo and in vitro. Our work uncovers a differentiation-specific rearrangement of the microtubule cytoskeleton in epidermis, and defines an essential role for DP in the process.
The antiinflammatory activity of IgG: the intravenous IgG paradox
Authors: Nimmerjahn Falk , Ravetch Jeffrey V.
Published: January 2007

How high doses of intravenous IgG (IVIG) suppress autoimmune diseases remains unresolved. We have recently shown that the antiinflammatory activity of IVIG can be attributed to a minor species of IgGs that is modified with terminal sialic acids on their Fc-linked glycans. Here we propose that these Fc-sialylated IgGs engage a unique receptor on macrophages that, in turn, leads to the upregulation of an inhibitory Fcγ receptor (FcγR), thereby protecting against autoantibody-mediated pathology.
Ordering of the Exponential of Quadratic Forms in Boson Operators and Some Applications
Authors: A Jannussis  , A Streclas  , N Patargias  , D Sourlas  , K Vlachos
Published: January 2007

In the present paper we order operators of the general form exp [αa2+ βa+2+ γ(a+a+aa+) + δa+ ϵa+], using parametric differentiation. Using this ordered form we derive the density matrices and the canonical Wigner distribution function of the harmonic oscillator and of the electromagnetic field in a simple straightforward manner.
Food plant diversity as broad-scale determinant of avian frugivore richness
Authors: Kissling W. Daniel , Rahbek Carsten , Böhning-Gaese Katrin
Published: January 2007

The causes of variation in animal species richness at large spatial scales are intensively debated. Here, we examine whether the diversity of food plants, contemporary climate and energy, or habitat heterogeneity determine species richness patterns of avian frugivores across sub-Saharan Africa. Path models indicate that species richness of
Ficus
(their fruits being one of the major food resources for frugivores in the tropics) has the strongest direct effect on richness of avian frugivores, whereas the influences of variables related to water–energy and habitat heterogeneity are mainly indirect. The importance of
Ficus
richness for richness of avian frugivores diminishes with decreasing specialization of birds on fruit eating, but is retained when accounting for spatial autocorrelation. We suggest that a positive relationship between food plant and frugivore species richness could result from niche assembly mechanisms (e.g. coevolutionary adaptations to fruit size, fruit colour or vertical stratification of fruit presentation) or, alternatively, from stochastic speciation–extinction processes. In any case, the close relationship between species richness of
Ficus
and avian frugivores suggests that figs are keystone resources for animal consumers, even at continental scales.
A neural-network reinforcement-learning model of domestic chicks that learn to localize the centre of closed arenas
Authors: Mannella Francesco , Baldassarre Gianluca
Published: January 2007

Previous experiments have shown that when domestic chicks (Gallus gallus) are first trained to locate food elements hidden at the centre of a closed square arena and then are tested in a square arena of double the size, they search for food both at its centre and at a distance from walls similar to the distance of the centre from the walls experienced during training. This paper presents a computational model that successfully reproduces these behaviours. The model is based on a neural-network implementation of the reinforcement-learning actor–critic architecture (in this architecture the ‘critic’ learns to evaluate perceived states in terms of predicted future rewards, while the ‘actor’ learns to increase the probability of selecting the actions that lead to higher evaluations). The analysis of the model suggests which type of information and cognitive mechanisms might underlie chicks' behaviours: (i) the tendency to explore the area at a specific distance from walls might be based on the processing of the height of walls' horizontal edges, (ii) the capacity to generalize the search at the centre of square arenas independently of their size might be based on the processing of the relative position of walls' vertical edges on the horizontal plane (equalization of walls' width), and (iii) the whole behaviour exhibited in the large square arena can be reproduced by assuming the existence of an attention process that, at each time, focuses chicks' internal processing on either one of the two previously discussed information sources. The model also produces testable predictions regarding the generalization capabilities that real chicks should exhibit if trained in circular arenas of varying size. The paper also highlights the potentialities of the model to address other experiments on animals' navigation and analyses its strengths and weaknesses in comparison to other models.
Artificial neural networks in models of specialization, guild evolution and sympatric speciation
Authors: Holmgren Noél M.A , Norrström Niclas , Getz Wayne M
Published: January 2007

Sympatric speciation can arise as a result of disruptive selection with assortative mating as a pleiotropic by-product. Studies on host choice, employing artificial neural networks as models for the host recognition system in exploiters, illustrate how disruptive selection on host choice coupled with assortative mating can arise as a consequence of selection for specialization. Our studies demonstrate that a generalist exploiter population can evolve into a guild of specialists with an ‘ideal free’ frequency distribution across hosts. The ideal free distribution arises from variability in host suitability and density-dependent exploiter fitness on different host species. Specialists are less subject to inter-phenotypic competition than generalists and to harmful mutations that are common in generalists exploiting multiple hosts.

When host signals used as cues by exploiters coevolve with exploiter recognition systems, our studies show that evolutionary changes may be continuous and cyclic. Selection changes back and forth between specialization and generalization in the exploiters, and weak and strong mimicry in the hosts, where non-defended hosts use the host investing in defence as a model. Thus, host signals and exploiter responses are engaged in a red-queen mimicry process that is ultimately cyclic rather then directional. In one phase, evolving signals of exploitable hosts mimic those of hosts less suitable for exploitation (i.e. the model). Signals in the model hosts also evolve through selection to escape the mimic and its exploiters. Response saturation constraints in the model hosts lead to the mimic hosts finally perfecting its mimicry, after which specialization in the exploiter guild is lost. This loss of exploiter specialization provides an opportunity for the model hosts to escape their mimics. Therefore, this cycle then repeats.

We suggest that a species can readily evolve sympatrically when disruptive selection for specialization on hosts is the first step. In a sexual reproduction setting, partial reproductive isolation may first evolve by mate choice being confined to individuals on the same host. Secondly, this disruptive selection will favour assortative mate choice on genotype, thereby leading to increased reproductive isolation.
And all who jumped died: the Triangle Shirtwaist factory fire
Authors: Lanier Pence Patricia , Phillips Carson Paula , Carson Kerry D. , Hamilton J. Brooke , Birkenmeier Betty
Published: January 2007

Suggests that the Triangle Shirtwaist factory fire in New York City in 1911 was the veritable genesis of laws safeguarding workers. The events of the 18‐minute inferno which killed 146 young, immigrant garment workers are summarized, as are the factory owners’ responses to the fire, along with the rationalizations they used to defend their lethal actions, which included moral justification, accusing the accuser, blaming the victim, advantageous comparison, responsibility displacement, responsibility diffusion, dehumanization, and blame attribution. Reviews workplace reforms initiated as a direct result of this fire and discusses why such historical disasters are unlikely to re‐occur if three simple lessons are heeded: first, it is unfortunate that it has required major trauma or carnage to awaken the public to the realities of existing dangers; second, mere compliance with existing statutes is often insufficient for protecting workers; and third, organizations which fail to self‐monitor will often be subjected to external control and regulation.
Situational characteristics and subjective career success
Authors: Nabi Ghulam R.
Published: January 2007

This paper examined the role of career‐enhancing strategies (CESs) as mediators of the relationship between situation‐centred characteristics (e.g. career prospects) and subjective career success. CESs included self‐nomination, networking behaviour and consultation with mentors. Subjective career success was measured using two criteria, intrinsic job success and perceived career success. Questionnaire data was collected from 283 full‐time support personnel in the UK. Results provided partial support for the mediating role of CESs between situational characteristics and subjective career success. Specific CESs played a mediating role in the relationship between specific situation‐centred variables and intrinsic job success. Self‐nomination and networking played a mediating role between career prospects and intrinsic job success. Networking also played a mediating role between security and intrinsic job success. The theoretical and practical implications of these findings are discussed, together with avenues for further research.
Term structure of forward exchange premiums: evidence from the 1920s
Authors: Rossiter R.D.
Published: January 2007

Following Clarida and Taylor, the term structure of forward exchange premiums can be interpreted as multiple cointegration vectors, if it is assumed that departures from the risk‐neutral efficient markets hypothesis are stationary. This hypothesis is tested using spot rates and one‐month and three‐month forward rates for six European countries during the 1920s floating rate era. Beginning in late 1924, speculation about a return to gold may have resulted in a non‐stationary forward premium. However, except for this speculative period, the term structure of forward premiums was stationary for three currencies. Thus the empirical results presented are broadly consistent with the analysis of Taylor and McMahon, MacDonald and Taylor and Miller and Sutherland.
Piero Sraffa and the revival of classical political economy
Authors: Bortis Heinrich
Published: January 2007

The first part of this article focuses on Roncaglia’s presentation of Piero Sraffa’s work and its significance for economic theory. The second part takes up some issues of content, method and interpretation of this work. It is argued that Sraffa must be put into a wider context to link him with Keynes. Sraffa and Keynes constitute the basis for elaborating a classical‐Keynesian system of political economy on a platform provided by Pasinetti’s vertically integrated labour model.
The “Roundtable” for school learning and planning groups: planting a seed for systemic renewal
Authors: Farr Gabriele Susan
Published: January 2007

Current public education, overwhelmed by piece‐meal reform efforts, is in need of systemic renewal. An investigation of key literature – systems methods, instructional design, and group process models – yields the conditions necessary for systemic change and a suitable base model. Namely, a successful systemic educational change effort is ideal‐based, holistic, continuing, participatory, user‐friendly, easy to adjust/improve, and emancipatory. A suitable base model is discovered in the learning systems of Alcoholics Anonymous and then built on for a new model: the Roundtable (RT) for secular learning. Briefly, the RT session is designed so that leadership and learning opportunities are distributed among all participants, who have equal time to present their ideas. Pilot studies in professional scientific organizations allowed refinement of the model. This study investigated sought the seven conditions in four RT applications in 4th‐grade classrooms in California. Participants at each site were the teacher and their 30±1 students. Each teacher held ten RT sessions, with students leading two to three of the last four sessions. Evidence was sought in the RT texts, session recordings, and users’ views. The criteria were met in the following ways. The RT applications were: ideal‐based in the RT texts; user‐friendly as they were user‐ready and engaging; easy to adjust/improve in the simple revision session tasks, and emancipatory as users learned in important, positive and unanticipated ways. The RT applications were holistic: found suitable for all classroom levels at both schools, and for all school groups at one school. They were continuing after the study in 2 or 3 of the four classrooms. They were very participatory in the roles of listener, reader, and speaker; somewhat participatory in the leader and co‐planner roles. Contributions to organizational /educational change theory and future projects are promising.
Objective measurement of pilling by image processing technique
Authors: Behera B.K. , Madan Mohan T.E.
Published: January 2007

Purpose

This paper aims to report on a new pilling measurement system that has been developed using image processing technique.

Design/methodology/approach

A pilling assessment cabinet is designed and developed which captures images and a software is developed to process and analyze the image of a pilled fabric to find out the various pilling parameters such as total number of pills, total area of the pills, mean area and number of pills per unit area. The image processing software processed image data of both the existing subjective assessment standards and pilled fabrics and assign suitable grades for comparison.

Findings

The grades assigned by the machine correlates well with that of the experts grades and the results are reliably reproducible. The system can count the number of pills, find their total area, and their mean area. The results of EMPA‐W2 and EMPA‐W3 standards behave almost similar. The ASTM standards also gives somewhat the same results as the EMPA standards in number of pills but has a wide variation in the pilled area and mean pill area. The IWS standards produced an entirely different result from the other two standards, which leads us to the conclusion that all these standards are not objectively comparable to each other.

Practical implications

The machine grade becomes a suitable methodology to compare the different grading systems.

Originality/value

Traditional pilling tests are subjective by nature. Moreover, standards set by different organizations are not comparable with each other. This method presents a more universal and objective approach to describe the nature of the pilling.
Implementing EDRM: has it provided the benefits expected?
Authors: Smyth Zoë A.
Published: January 2007

Purpose

To analyse the lessons learned from the Electronic Document and Records Management (EDRM) project at the Public Record Office of Northern Ireland to inform other practitioners.

Design/methodology/approach

Using PRINCE II project methodology the EDRM project objectives were to re‐introduce best practice records management following ISO 15489 as the standard, implement software that met the 2002 functional requirements devised by The National Archives UK and provide a detailed lessons‐learned report to inform the wider roll‐out to 18,000 users in the Northern Ireland Civil Service.

Findings

Develops practical lessons learned and highlights key issues and risks with a project of this nature and identifies some of the initial business benefits that can be achieved.

Research limitations/implications

The Public Record Office of Northern Ireland was a relatively small organisational project and, due to the remit of the agency senior management support, which is critical, was somewhat easier to obtain.

Practical implications

This paper is a useful case study investigation of a project management approach to the introduction of EDRM within an organisation using ISO 15489 as a tool.

Originality/value

This paper reflects practical lessons learned from a successful implementation of EDRM and will help other professionals who are considering or already introducing EDRM in their own organisations.
Supply chain risk management
Authors: Jüttner Uta
Published: January 2007

Purpose

This paper seeks to understand business requirements for supply chain risk management (SCRM) from a practitioner perspective.

Design/methodology/approach

Based on the findings from an exploratory quantitative survey and qualitative focus group discussions with supply chain managers, some issues of SCRM are derived and structured along the three conceptual levels of “philosophy”, “principles” and “processes”.

Findings

The survey showed that 44 per cent of all eight responding companies expect the vulnerability of their supply chains to increase in the next five years. However, the concept of SCRM is still in its infancy.

Originality/value

The paper contributes to our knowledge on SCRM by presenting the business requirements from a practitioner perspective and by deriving a structure for an integrated approach to SCRM which can guide further research.