bluuebunny/crossref_metadata_2025 huggingface dataset:
Particle monolayer formation at the air–water interface by silica particle with well‐defined grafted polymer
Authors: Mouri Emiko , Okazaki Yoshitaka , Tatsuno Shintaro , Karakawa Hiroyuki , Yoshinaga Kohji
Published: August 2006

Particle monolayer formation at the air–water interface by polymer‐grafted colloidal silica was investigated. Methyl methacrylate (MMA) was polymerized from initiative bromide groups at colloidal silica surface by atom transfer radical polymerization. We obtained polymer‐grafted silica particle (SiO2‐PMMA) with relative narrow polydispersity of PMMA. For the polymer‐grafted particle with high graft density, particle monolayer formation was confirmed by π‐A isotherm measurement and SEM observation. Interparticle distance was controllable by surface pressure. Furthermore, grafted polymer chains were suggested to be fairly extended at the air–water interface. However, for the polymer‐grafted particle with low graft density, monolayer structure on substrate showed aggregation and voids. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 2789–2797, 2006
Thermal properties and crystalline structure of syndiotactic polystyrene‐based miscible blends
Authors: Chiu Fang‐Chyou , Lau Chun‐Saang
Published: August 2006

This work examined the effect of the pre‐melting temperature (Tmax) on the thermal properties and crystalline structure of four miscible syndiotactic polystyrene (sPS)‐based blends containing 80 wt % sPS. The counterparts for sPS included a high‐molecular‐weight atactic polystyrene [aPS(H)], a medium‐molecular‐weight atactic polystyrene [aPS(M)], a low‐molecular‐weight atactic polystyrene [aPS(L)], and a low‐molecular‐weight poly(styrene‐co‐α‐methyl styrene) [P(S‐co‐αMS)]. According to differential scanning calorimetry measurements, upon nonisothermal melt crystallization, the crystallization of sPS shifted to lower temperatures in the blends, and the shift followed this order of counterpart addition: P(S‐co‐αMS) > aPS(L) > aPS(M) > aPS(H). The change in Tmax (from 285 to 315 °C) influenced the crystallization of sPS in the blends to different degrees, depending on the counterpart's molecular weight and cooling rate. The change in Tmax also affected the complex melting behaviors of pure sPS and an sPS/aPS(H) blend, but it affected those of the other blends to a lesser extent. Microscopy investigations demonstrated that changing Tmax slightly affected the blends' crystalline morphology, but it apparently altered that of pure sPS. Furthermore, the X‐ray diffraction results revealed that the α‐form sPS crystal content in the blends generally decreased with an increase in Tmax, and it decreased with a decrease in the cooling rate as well. The blends showed a lower α‐form content than pure sPS; a counterpart of a lower molecular weight more effectively reduced the formation of α‐form crystals. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 2798–2810, 2006
Study of the Daughter Products of Akardite‐II
Authors: Lussier Louis‐Simon , Bergeron Eric , Gagnon Hélène
Published: August 2006

In this work, five akardite‐II (AK‐II) daughter products were produced and isolated. Their respective MS, NMR, IR and UV spectra were recorded. These five products were positively identified as: N‐NO‐AK‐II, 2‐NO2‐AK‐II, 4‐NO2‐AK‐II, N‐NO‐2‐NO2‐AK‐II and N‐NO‐4‐NO2‐AK‐II. An HPLC method giving baseline separation of 6 AK‐II family products and 10 diphenylamine (DPA) family products is also described. Finally, preliminary results concerning the stability of AK‐II daughter products are discussed.
Alkali‐Dinitramide Salts Part 2: Oxidizers for Special Pyrotechnic Applications
Authors: Berger Beat P. , Mathieu Jörg , Folly Patrick
Published: August 2006

Ammonium dinitramide is planned to be a substitute for commonly used oxidizers in rocket motor compositions. Different teams worldwide have already synthesized alkali salts of dinitramide and several times it was used as an oxidizer for pyrotechnic compositions containing boron as a reducing agent. In this paper the results of a systematic investigation to characterize the pyrotechnic redox systems titanium/potassium dinitramide and titanium/cesium dinitramide are presented and the data are compared. The heats of reaction as well as the burning rates of the redox system titanium/potassium dinitramide are higher than those of the redox system titanium/cesium dinitramide. Both systems show a moderate sensitivity to friction and electrostatic discharges. However the sensitivity of mixtures of both redox systems shows a very high sensitivity to impact. These sensitivities are in the range of pure HMX or pentaerythritol tetranitrate.
Radiative Ignition of Fine‐Ammonium Perchlorate Composite Propellants
Authors: Cain Jeremy , Brewster M. Quinn
Published: August 2006

Radiative ignition of quasi‐homogeneous mixtures of ammonium perchlorate (AP) and hydroxyterminated polybutadiene (HTPB) binder has been investigated experimentally. Solid propellants consisting of fine AP (2 μm) and HTPB binder (~ 76/24% by mass) were ignited by CO2 laser radiation. The lower boundary of a go/no‐go ignition map (minimum ignition time vs. heat flux) was obtained. Opacity was varied by adding carbon black up to 1% by mass. Ignition times ranged from 0.78 s to 0.076 s for incident fluxes ranging from 60 W/cm2 to 400 W/cm2. It was found that AP and HTPB are sufficiently strongly absorbing of 10.6 μm CO2 laser radiation (absorption coefficient ≈250 cm−1) so that the addition of carbon black in amounts typical of catalysts or opacitymodifying agents (up to 1%) would have only a small influence on radiative ignition times at 10.6 μm. A simple theoretical analysis indicated that the ignition time‐flux data are consistent with in‐depth absorption effects. Furthermore, this analysis showed that the assumption of surface absorption is not appropriate, even for this relatively opaque system. For broadband visible/near‐infrared radiation, such as from burning metal/oxide particle systems, the effects of in‐depth absorption would probably be even stronger.
Crystal Structure, Thermal Decomposition and Properties of Cesium 3,5‐Dihydroxy‐2,4,6‐Trinitrophenolate
Authors: Chen Hongyan , Zhang Tonglai , Zhang Jianguo , Chen Chunchun
Published: August 2006

A coordination polymer, cesium 3,5‐dihydroxy‐2,4,6‐trinitrophenolate ([Cs(DHTNP)]n), has been synthesized and its crystal structure determined. This crystal belongs to the monoclinic system with space group Pc. Each Cs+ is coordinated to 12 oxygen atoms from 8 different 3,5‐dihydroxy‐2,4,6‐trinitrophenolate (DHTNP−) anions, and each DHTNP− anion is coordinated with 8 Cs+ cations. The oxygen atoms of the phenolic hydroxyl group and from all of the nitro groups of the DHTNP− anion simultaneously bind to neighboring Cs+ ions. These DHTNP− molecular chains are interlaced, with the cesium atoms acting as knots, to create an infinite three‐dimensional network structure. The molecules are linked by electrostatic interactions and weak van der Waals, forces and also display intramolecular hydrogen bonding, which all enhance the thermal stability of the title compound. The thermal decomposition was studied using DSC, TG‐DTG and IR techniques. The results exhibit characteristics of a highly energetic compound that undergoes two highly exothermic decomposition reaction processes from 166 °C to 300 °C under the condition of a linear heating rate. The experimental sensitivity results indicate that [Cs(DHTNP)]n is quite sensitive to impact and friction.
Air Gap Effects in LX‐17
Authors: Souers P. Clark , Ault Stan , Avara Rex , Bahl Kerry L. , Boat Ron , Cunningham Bruce , Gidding Doug , Janzen Jim , Kuklo Denise , Lee Ron , Lauderbach Lisa , Weingart Richard C. , Wu Ben , Winer Kris
Published: August 2006

Three experiments done over twenty years on gaps in LX‐17 are described. For the detonation front moving parallel to the gaps, jets of gas products were seen coming from the gaps at velocities 2 to 3 times greater than the detonation velocity. A case can be made that the jet velocity increased with gap thickness but the data are scattered. For the detonation front moving transverse to the gap, time delays were seen. The delays roughly increase with gap width, going from 0–70 ns at “zero gap” to around 300 ns at 0.5–1 mm gap. Larger gaps of up to 6 mm width almost certainly stopped the detonation, but this was not proved. Real‐time resolution of the parallel jets and determination of the actual re‐detonation or failure in the transverse case needs to be achieved in future experiments.
Relationship between the Bond Dissociation Energies and Impact Sensitivities of Some Nitro‐Explosives
Authors: Song Xiao‐Shu , Cheng Xin‐Lu , Yang Xiang‐Dong , He Bi
Published: August 2006

The bond dissociation energy (BDE) for removal of the NO2 group for eleven CHNO nitro‐containing explosive molecules is studied to find its correlation with impact sensitivity. The BDE for removal of the NO2 group in nitroaromatic molecules with nitro alkyl, and esters with nitro alkyl, is calculated using the B3LYP method of Density Functional Theory with the 6‐31G* basis set. The relationship between the impact sensitivities and the weakest C‐NO2 bond dissociation energy values is examined. The results indicate a nearly linear correlation between the impact sensitivity and the ratio of the BDE value to the total molecular energy.
Studies on RDX Influence on Performance Increase of Triple Base Propellants
Authors: Sanghavi Rakesh R. , Khire V. H. , Chakraborthy T. K. , Singh Amarjit
Published: August 2006

Conventional triple base propellants are currently used for high performance tank and field gun ammunition. The aim of the present study was to improve the chemical energy of the triple base propellant by partial replacement of picrite by RDX to achieve higher force constant (F) and lower specific heat ratio (γ). Details of theoretical and experimental studies carried out on six triple base propellant formulations are discussed in this paper. It can be concluded that partial replacement of picrite by RDX in the triple base propellant formulations achieved higher chemical energy as well as improved ballistic performance.
Solubility and Diffusivity of Polyethyl Acrylate in Supercritical Carbon Dioxide
Authors: Wallace Julie A. , Bell David A.
Published: August 2006

An alternative plastic‐bonded molding powder production process would use a polymeric binder dissolved in supercritical carbon dioxide rather than the liquid organic solvents currently used. This research investigated the solubility and diffusion coefficients of polyethyl acrylate, a potential binder, in supercritical carbon dioxide. Over the range of solvent conditions investigated, the dissolved polymer concentration was 0.036 wt% or less. A practical molding powder production process is not likely with such a dilute binder solution.
An Investigation of the Performance of a Boron/Potassium‐Nitrate Based Pyrotechnic Igniter
Authors: Ulas Abdullah , Risha Grant A. , Kuo Kenneth K.
Published: August 2006

The performance of a boron/potassium‐nitrate based pyrotechnic igniter, used as an initiator in airbag gas generators, was investigated at different initial temperatures. Igniter firings were conducted in a small vented combustion chamber in order to measure the instantaneous chamber pressures. A theoretical model, which considers multi‐phase products and lumped chamber parameters, was adopted to determine the discharging gas phase and condensed phase mass flow rates from the igniter. The data reduction model used experimentally obtained pressure‐time traces and the total burned mass as input data. The calculated instantaneous mass flow rates of the igniter at various initial temperatures showed that the initial temperature has a major influence on the igniter's performance. For the temperature range tested (−20 °C to 60 °C), the pressurization rate and the total mass flow rate of the igniter increased with temperature and ranged from 322 GPa/s to 721 GPa/s and 4.3 kg/s to 6.1 kg/s, respectively. It was found that the condensed‐phase products comprised the majority of the igniter discharge products. The mass fraction of the condensed‐phase products indicated a weak dependency on initial igniter temperature. Under similar test conditions, the recorded pressure‐time traces during igniter firings were found to be quite reproducible.
Automatic loop shaping in QFT using hybrid optimization and constraint propagation techniques
Authors: S. V. Paluri Nataraj , Kubal Nandkishor
Published: August 2006

An efficient method for automatic loop shaping in Quantitative Feedback Theory (QFT) is proposed. The proposed method uses hybrid optimization and constraint propagation techniques. The hybrid optimization part combines interval global optimization and nonlinear local optimization methods. To supplement the optimization tools, a quick solution approach is developed based on ideas of constraint propagation. The quick solution is found to be quite effective in discarding infeasible controller parameter regions in the optimization search. The proposed overall method is demonstrated on an example taken from the QFT literature where it automatically synthesizes a QFT controller of given structure in quick time. Copyright © 2006 John Wiley & Sons, Ltd.
Challenge of multiple co‐primary endpoints: a new approach
Authors: Chuang‐Stein Christy , Stryszak Paul , Dmitrienko Alex , Offen Walter
Published: August 2006

There are many disorders where regulatory agencies have required a new treatment to demonstrate efficacy on multiple co‐primary endpoints, all significant at the one‐sided 2.5 per cent level, before accepting the treatment's effect for the disorder. This requirement, rooted in the intersection–union (IU) test, has led many researchers to increase the study sample size to make up for the reduction in the statistical power at the study level. Unfortunately, the increase in sample size could be substantial when the endpoints are minimally correlated and the treatment effects on the multiple endpoints are comparable. In this paper, we demonstrate that the frequentist concept of controlling the maximum false positive rate, even when applied to a restricted null space, has only limited success in keeping the sample size increase at a reasonable level. We therefore propose an approach that is based on the notion of controlling an average type I error rate. By employing an upper bound for the average type I error rate, the new approach provides an adjustment to the significance level that depends only on the correlation among the endpoints. For the most common case of two or three co‐primary endpoints, the adjusted significance level is at most 5 per cent (one‐sided) when the endpoints are moderately correlated. We show how sample size could be calculated under the proposed approach and contrast the needed sample size with that required under the IU test. We provide additional comments and discuss why the new approach is consistent with the principle requiring evidence of significance in the drug development and approval process. Copyright © 2006 John Wiley & Sons, Ltd.
International acquisition and other growth strategies: Some lessons from the food and drink industry
Authors: Lynch Richard
Published: August 2006

This article explores profitable international growth strategies when markets are mature through a two‐stage study of companies in the food and drink industry. The first stage assessed 400 announcements about such strategies made by medium‐ and large‐sized food and drink firms in the period 1998–2001. The second stage examined in depth the international growth strategies of the world's 35 leading food and drink companies over the period 1985–2001. Both stages showed that acquisition was the most widely used method of international expansion. The second stage suggested that organic international growth (i.e., based on the company's current product portfolio) was the other main option for such expansion. Importantly, the international acquisition route was usually focused on the existing product portfolio of a company. In this sense, there was clear convergence between the purpose of an international acquisition (i.e., to support or enhance the existing product portfolio outside the home country) and the broader company purpose of delivering successful organic growth from its current range of products. The second study also suggested that international acquisitions can bring faster sales growth than organic activity but come with greater risk and other potential problems. The research identified some practical lessons derived from such strategies in the food and drink industry. © 2006 Wiley Periodicals, Inc.
Managing micropolitical risk: A cross‐sector examination
Authors: Alon Ilan , Gurumoorthy Rajesh , Mitchell Matthew C. , Steen Teresa
Published: August 2006

This article stresses the need for today's multinational firms to adopt their own political risk‐assessment and risk‐mitigation strategies. A comparative study of the energy, financial, and automobile sectors illustrates the need for all companies in these sectors to undertake comprehensive risk‐assessment strategies. Risk‐assessment models established by leading multinationals like British Petroleum, Bank of America, and General Motors are examined as examples that other companies in these sectors can build upon. The consistent micropolitical risk variables then lead to a proposed practical framework for examining sector‐specific micropolitical risk. © 2006 Wiley Periodicals, Inc.
Measuring service content: A scale development
Authors: Cloninger Peggy A. , Oviatt Benjamin
Published: August 2006

This research presents the development of an instrument for measuring the service content (the degree of intangibility, perishability, simultaneity, and heterogeneity) characterizing a firm's output. Service characteristics are acknowledged to be important strategic variables, and the characteristic of intangibility has been studied extensively. The scale presented here is an improvement over previous methods. In contrast to previous methods that have relied on various categorizations, or that have examined only intangibility or service quality, the scale presented here can provide a numerical measure of all four of the most important service characteristics. This can be used in future research efforts to examine the influence of service characteristics on firm internationalization, firm strategies, and performance. © 2006 Wiley Periodicals, Inc.
China—The new paradox
Authors: Antoniou Peter H.
Published: August 2006

Ian Rae and Morgan Witzel. 2004. Singular and Different: Business in China, Past, Present and Future. New York: Palgrave Macmillan. 173 pages. ISBN: 1‐4039‐1722‐1.

Sheila Oakley. 2002. Labor Relations in China's Socialist Market Economy. Westport, CT: Quorum Books. 231 pages. ISBN: 1‐56720‐589‐5.

Ilan Alon (Ed.). 2003. Chinese Culture, Organizational Behavior, and International Business Management. Westport, CT: Praeger. 270 pages. ISBN: 1‐56720‐456‐1.
Enhancement of bupivacaine local anesthesia with the potassium channel blocker ibutilide
Authors: Smith Forrest L. , Lindsay Raymond J.
Published: August 2006

In some clinical settings it is necessary to inject large volumes of local anesthetic – and consequently very high doses – in order to provide an adequate level of block. Subsequent absorption of these high doses, or inadvertent intravenous administration of even small doses, has led to systemic toxicity. Thus, it is desirable to develop adjuvants that are inert alone, but would enhance the potency and/or efficacy of local anesthetics to improve their safety. Adelta/C fibers possessK+channels identified as sustained delayed rectifier typeKDRcurrents and transient A‐typeKAcurrents. In the heart, the class III antiarrhythmic drug ibutilide blocks the cardiac component of the rapid delayed rectifyingK+current (IKr). Experiments were conducted to determine whether co‐administration of theK+channel blocker ibutilide would enhance the local anesthetic bupivacaine in mice. After injecting bupivacaine mixed with vehicle or ibutilide in the popliteal region of mice, paw withdrawal latencies were determined by applying the plantar aspect of a single hind‐paw to the surface a 55°C hot‐plate device. 0.5% Bupivacaine+ibutilide (7.8×10−5M) elicited significantly longer hot‐plate latencies than 0.5% bupivacaine+vehicle. In addition, bupivacaine was 2.6‐fold more potent when co‐administered with ibutilide rather than vehicle. Epinephrine extends the tissue concentrations of local anesthetics by inducing localized vasoconstriction. Epinephrine augmented the enhancement by ibutilide of bupivacaine's potency by 6.8‐fold. In summary, ibutilide may enhance the effects of bupivacaine by blockingK+channels on sensory nociceptive nerves.
Nm23 expression in node‐positive and node‐negative endometrial cancer
Authors: Yalçinkaya U. , Özuysal S. , Bilgin T. , Ercan I. , Saraydaroglu Ö. , Demir D.
Published: August 2006

Objective: To examine the relationships between the expression of protein Nm23 and surgical stage, histologic grade, histopathologic findings, and survival in women with endometrial carcinoma.

Methods: 19 patients with lymph node involvement were matched with 24 patients without lymph node involvement and the best paraffin‐embedded blocks were selected for Nm23 immunohistochemical staining. The slides were evaluated semiquantitatively according to their degree of cytoplasmic staining. Statistical analysis was performed to determine whether there was a relationship between Nm23 expression and surgical stage, histologic grade, depth of myometrial invasion, lymph node metastasis, and/or lymphovascular space involvement. Survival analysis was also performed.

Results: Slides from 15 patients (79%) with lymph node involvement and 22 patients (88%) without lymph node involvement were found to be positive for Nm23 (P = 0.01). No significant relations were observed between Nm23 expression and surgical stage, histologic grade, depth of myometrial invasion, or lymphovascular space involvement. Nm23 expression was found to be significantly related to lower rates of lymph node metastasis and longer survival (P = 0.02).

Conclusion: Elevated Nm23 expression is related to lower rates of lymph node metastasis and longer survival.
Measurement of blood loss at childbirth and postpartum
Authors: Kavle J.A. , Khalfan S.S. , Stoltzfus R.J. , Witter F. , Tielsch J.M. , Caulfield L.E.
Published: August 2006

Objective: To accurately measure blood loss during childbirth in a developing country.

Method: The alkaline hematin technique was used to quantify blood lost during delivery and 24 h postpartum in 158 women in Pemba Island, Zanzibar.

Result: Women were found to lose less blood during childbirth and 24 h postpartum than previously reported. Compared with laboratory values, nurse–midwives approximated blood loss accurately (mean difference, i.e., mean underestimation by nurse–midwives, 4.90 mL); however, their imprecision was greater for higher laboratory values.

Conclusion: This study may prompt further investigation, as no comparable data exist for developing countries where maternal mortality is high and severe anemia prevalent.
Postmenopausal hormone therapy and quality of life
Authors: Smith A.J. , Hall D.R. , Grové D.
Published: August 2006

Objective:To evaluate whether hormonal therapy (HT) had any significant effect on quality of life (QoL) in a selected group of postmenopausal women.

Methods: The study was conducted in a specialist private practice in Tygerberg, Cape Town, South Africa, over an 18‐month period ending in July 2003. A questionnaire using the Utian Quality of Life (UQoL) scale was posted to all women with established postmenopausal status, seen over this period. 541 questionnaires were posted, 421 returned and 398 could be used. Women gave written informed consent.

Results: The average age of the women was 60 years. 313 women (78.6%) were using hormone therapy (HT) while 275 women (69.1%) reported concomitant medical problems. HT users had significantly higher scores in three of the four QoL domains, namely, occupational (p = 0.046), emotional (p = 0.03), and sexual (p = 0.009). There was no significant difference in the health domain (p = 0.2).

Conclusion: This study found that post‐menopausal South African women experienced that HT had a positive effect on global quality of life.
Quaternary depositional patterns and sea-level fluctuations, Northeastern North Carolina
Authors: Parham Peter R. , Riggs Stanley R. , Culver Stephen J. , Mallinson David J. , Wehmiller John F.
Published: August 2006

A detailed record of late Quaternary sea-level oscillations is preserved within the upper 45 m of deposits along an eight km transect across Croatan Sound, a drowned tributary of the Roanoke/Albemarle drainage system, northeastern North Carolina. Drill-hole and seismic data reveal nine relatively complete sequences filling an antecedent valley comprised of discontinuous middle and early Pleistocene deposits. On interfluves, lithologically similar marine deposits of different sequences occur stacked in vertical succession and separated by ravinement surfaces. Within the paleo-drainage, marine deposits are separated by fluvial and/or estuarine sediments deposited during periods of lowered sea level. Foraminiferal and molluscan fossil assemblages indicate that marine facies were deposited in a shallow-marine embayment with open connection to shelf waters. Each sequence modifies or truncates portions of the preceding sequence or sequences. Sequence boundaries are the product of a combination of fluvial, estuarine, and marine erosional processes. Stratigraphic and age analyses constrain the ages of sequences to late Marine Isotope Stage (MIS) 6 and younger (∼ 140 ka to present), indicating multiple sea-level oscillations during this interval. Elevations of highstand deposits associated with late MIS 5 and MIS 3 imply that sea level was either similar to present during those times, or that the region may have been influenced by glacio-isostatic uplift and subsidence.
Preliminary statistical studies of the infraspecific variation in the ascospores of Nesolechia oxyspora growing on different genera of parmelioid lichens
Authors: DORÉ Caroline J. , COLE Mariette S. , HAWKSWORTH David L.
Published: August 2006

In order to ascertain the extent of possible host-specialization in the Nesolechia oxyspora complex, as a pilot study ascospores from 20 collections from different parmelioid hosts representing seven genera were drawn, measured, and had length:breadth ratios calculated. The data were then subjected to multiple regression analysis using Huber-White sandwich estimators of standard errors (apparently not previously used in mycology) which take account of spores not necessarily being independent variables as they might come from the same ascus, and a statistical analysis. Significant differences between collections from seven genera were found. While the sample size was too small to reach definite conclusions, it is clear that there is a finer degree of host-relatedness than hitherto expected, which may be geno- or phenotypic. A more extensive study including species from a wider range of hosts and complemented by molecular methods will be necessary to further elucidate degrees of specificity and cryptic co-speciation in the complex. A list of the 63 reported lichen hosts is included; these are distributed though 19 genera.
Chlorophyll a fluorescence in transplants of Parmelia sulcata Taylor near a power station (La Robla, León, Spain)
Authors: FERNÁNDEZ-SALEGUI Ana B. , CALATAYUD Ángeles , TERRÓN Arsenio , BARRENO Eva M.
Published: August 2006

Healthy thalli of Parmelia sulcata Taylor were transplanted to 8 localities in the surroundings of a power station (La Robla, León, Spain), the sole pollution source in the region. Changes in chlorophyll a fluorescence were monitored in the transplants 12 months, 18 months and 24 months after transplantation. Statistically significant differences were observed in the ratio of variable to maximal fluorescence, non-photochemical fluorescence quenching and vitality index. The decrease in fluorescence parameters was higher in the localities of Cuadros and Rabanal de Fenar, which are situated a few kilometres away from the power station and in the same direction as the prevailing winds.
Field study on the regenerative capacity of three calcicolous lichen species damaged by snail grazing
Authors: Fröberg Lars , Baur Anette , Baur Bruno
Published: August 2006

Lichen growth and regeneration depend on the net photosynthetic production, the lateral allocation of products, on abiotic factors, competition and herbivory, and may therefore vary both in space and time (Hill 1981). Herbivores cause different damage to lichens in response to different thallus structure (surface toughness) and growth form, presence/absence of secondary compounds, and due to herbivore-specific differences in feeding (Lawrey 1984; Fröberg et al. 1993; Baur et al. 1994; Hesbacher et al. 1995). Regeneration of artificially damaged lichen tissue has been investigated in detail, for example in Xanthoria parietina (L.) Th. Fr. (Honegger 1996; Honegger et al. 1996). However, quantitative assessments of the regenerative capacity of thalli damaged by herbivores are so far lacking. Damage to lichens by grazing gastropods is made by highly specialized radulae and can therefore not be imitated by any mechanical treatment (Baur et al. 2000). Herbivory by snails also involves the production of saliva and mucus, which both could affect lichen regeneration.
Actin type I introns offer potential for increasing phylogenetic resolution in Asterochloris (Chlorophyta: Trebouxiophyceae)
Authors: NELSEN Matthew P. , GARGAS Andrea
Published: August 2006

Primers are presented to amplify an intron-containing portion of the actin type I locus from Asterochloris algae. The amount of variation and phylogenetic resolution provided by the ITS rDNA are compared with that from the actin locus. The number of variable and parsimony-informative sites within the actin locus was drastically higher than that of the ITS. Phylogenetic analyses of the ITS resulted in poorly resolved trees with low support values. In contrast, phylogenetic analyses of the actin locus yielded trees with better support and resolution. It is concluded that the actin type I introns will be useful for studies investigating species concepts and population genetics.
UV-B induces usnic acid in reindeer lichens
Authors: NYBAKKEN Line , JULKUNEN-TIITTO Riitta
Published: August 2006

Induction of secondary compounds in three reindeer lichens (Cladonia arbuscula, C. rangiferina and C. stellaris) was studied under controlled conditions in a growth chamber. Acetone rinsed (secondary compounds removed) lichen mats were subjected to three light regimes (PAR, PAR+UV-A and PAR+UV-A+UV-B), each combined with simulated herbivory (clipping). After 4 weeks, lichen extracts were analyzed by HPLC for any synthesized secondary compounds. UV-B induced the synthesis of usnic acid in C. arbuscula and C. stellaris and melanic pigments in C. rangiferina. Atranorin, fumarprotocetraric acid and perlatolic acid were not influenced by light quality. None of the identified compounds were significantly influenced by clipping. In conclusion, all three lichen species responded to UV-B radiation by developing cortical UV-B absorbing pigments that might function as protective screens. However, the experiment did not produce evidence for a herbivore-deterrent role of compounds studied.
Porina pilifera (Porinaceae), a new foliicolous lichen from Costa Rica (Central America)
Authors: NEUWIRTH Gerhard , PFALLER Kristian
Published: August 2006

Porina pilifera Neuwirth sp. nov. is described from Costa Rica. It is similar to P. palmicola, but differs in having smaller ascospores 27–36×3–4 μm. Porina pilifera is only known from the type locality in tropical Central America, where it grows on the leaves of palm trees.
Phylogenetic position of a Pacific Northwest North American endemic cyanolichen, Nephroma occultum (Ascomycota, Peltigerales)
Authors: PIERCEY-NORMORE Michele D. , COXSON Darwyn , GOWARD Trevor , GOFFINET Bernard
Published: August 2006

Nephroma occultum is a COSEWIC listed cyanolichen of “Special Concern”. It is endemic to old-growth cedar-hemlock forests in western North America. This is the first study to place N. occultum into a phylogenetic framework using nucleotide sequence and secondary structure data. It also addresses the phylogenetic relationship between N. occultum and N. arcticum. Analysis of fungal Internal Transcribed Spacer (ITS) ribosomal DNA (rDNA) produced four major clades. The cyanobacterial transfer RNALeu intron (tRNALeu) from N. occultum was separated from that of N. isidiosum and fell between the Eurasian and North American epiphytic taxa. Examination of length and complexity of the folded secondary structures revealed different trends in the ITS1 and ITS2 rRNA regions. Even though N. occultum is endemic to North America, it seems more closely related to South American temperate rainforest species than to the sympatric N. arcticum. Nephroma occultum is alone among the studied species of Peltigerales in having an exceptionally long ITS1 region, and a different tRNALeu intron DNA sequence of the photobiont suggesting association with a unique genotype of Nostoc. It may be argued that the fitness of N. occultum may be influenced by the complex ITS1 RNA structure, a unique photobiont genotype undergoing a genetic bottleneck, no sexual reproduction to generate variation, and the inability to associate with different photobionts to adapt to changing habitats.
A new Bacidia with long-necked pycnidia from Central Europe
Authors: CZARNOTA Paweł , COPPINS Brian J.
Published: August 2006

Bacidia pycnidiata sp. nov. (Ramalinaceae) is described from Poland and the Czech Republic. It is the first species within Bacidia s. lat., referable to the Bacidina group, known to have sessile, long-necked, lageniform pycnidia bearing straight macroconidia. It has been found growing on saxicolous as well as on corticolous bryophytes and directly on bark of deciduous trees within young, hardly changed woodlands or in the vicinity of human settlements.
Two new brown-spored species of Pertusaria from south-western North America
Authors: SCHMITT Imke , LUMBSCH H. Thorsten , BRATT Charis
Published: August 2006

Two new Pertusaria species with brown ascospores are described from southern California and Baja California, Mexico. Pertusaria islandica sp. nov. is characterized by pertusariate to pseudolecanorate ascomata, ellipsoid ascospores, 8-spored asci, a strongly K+ violet reacting epithecium, and the presence of the 2′-O-methylperlatolic acid chemosyndrome, while P. occidentalis sp. nov. has pertusariate ascomata, globose to subglobose ascospores, 8-spored asci, and contains the arthothelin chemosyndrome. Pertusaria ochracea Kremp. is reduced to synonymy with P. melanospora Nyl.
Mesoscale simulations of atmospheric flow and tracer transport in Phoenix, Arizona
Authors: Wang Ge , Ostoja‐Starzewski Martin
Published: August 2006

Large urban centres located within confining rugged or complex terrain can frequently experience episodes of high concentrations of lower atmospheric pollution. Metropolitan Phoenix, Arizona (United States), is a good example, as the general population is occasionally subjected to high levels of lower atmospheric ozone, carbon monoxide and suspended particulate matter. As a result of dramatic but continuous increase in population, the accompanying environmental stresses and the local atmospheric circulation that dominates the background flow, an accurate simulation of the mesoscale pollutant transport across Phoenix and similar urban areas is becoming increasingly important. This is particularly the case in an airshed, such as that of Phoenix, where the local atmospheric circulation is complicated by the complex terrain of the area.

Within the study presented here, a three‐dimensional time‐dependent mesoscale meteorological model (HOTMAC) is employed for simulation of lower‐atmospheric flow in Phoenix, for both winter and summer case‐study periods in 1998. The specific purpose of the work is to test the model's ability to replicate the atmospheric flow based on the actual observations of the lower‐atmospheric wind profile and known physical principles. While a reasonable general agreement is found between the model‐produced flow and the observed one, the simulation of near‐surface wind direction produces a much less accurate representation of actual conditions, as does the simulation of wind speed over 1,000 metres above the surface. Using the wind and turbulence output from the mesoscale model, likely particle plume trajectories are simulated for the case‐study periods using a puff dispersion model (RAPTAD). Overall, the results provide encouragement for the efforts towards accurately simulating the mesoscale transport of lower‐atmospheric pollutants in environments of complex terrain. Copyright © 2006 John Wiley & Sons, Ltd.
On the use of the digital elevation model to estimate the solar radiation in areas of complex topography
Authors: Tovar‐Pescador J. , Pozo‐Vázquez D. , Ruiz‐Arias J. A. , Batlles J. , López G. , Bosch J. L.
Published: August 2006

The development of solar energy as a power source in the next few years requires reliable estimation of available solar energy resources. At local scales, topography is the most important factor in determining the distribution of solar radiation at the surface. Interpolation techniques are usually employed to estimate solar radiation where stations are not available, but their usefulness is limited where topography is an important source of variability. The use of satellite data and more recently of models based on techniques GIS, have contributed to solve this difficulty. In this work the usefulness of a digital elevation model (DEM) in providing topographic information for the estimation of solar radiation in areas of complex topography is analysed. Daily global radiation values were generated using the Solar Analyst software, which uses topographic information to generate radiation data. The generated data were compared with the experimental data obtained from 14 radiometric stations located within the Sierra Nevada Natural Park (southern Spain), an area of complex topography. Results show the usefulness of the topographic information derived from a DEM to estimate the solar radiation in areas of complex topography. Nevertheless, results depend on the DEM resolution and it is important that other factors, such as the albedo, should also be taken into account to obtain better estimates. Copyright © 2006 John Wiley & Sons, Ltd.
High resolution studies of the Gibraltar Levanter validated using sun‐glint anemometry
Authors: Capon R. A.
Published: August 2006

The Levanter is an easterly wind which frequently blows for several hours through the Strait of Gibraltar in summer. In the presence of a strong capping inversion, a synoptic or local scale pressure gradient forces the air through the gap between the orography on either side of the Strait. This flow cannot be resolved with either a global NWP model or a simplified linear model. Results from two Levanter cases, run using the Met Office Unified Model Version 5.3 at 1 km horizontal resolution over a 300×250 km limited area domain covering the Strait of Gibraltar, are presented, together with an unexpected source of verification. Copyright © 2006 John Wiley & Sons, Ltd.
Economic values of the APCN multi‐model ensemble categorical seasonal predictions
Authors: Kar Sarat C. , Hovsepyan Anahit , Park C. K.
Published: August 2006

The skill of seasonal mean precipitation and temperature predictions by multi‐model ensemble (MME) schemes has been examined using hindcast data from the APEC Climate Network (APCN). The hindcast data of the member models have been collected from several institutions in the APEC region. Skill metrics, namely, anomaly correlation coefficient (ACC), Hanssen‐Kuipers skill (HKS), and economic value were used to assess the APCN MME predictions. The member models have a range of skills in predicting the seasonal mean conditions: however, the MME schemes consistently produce improved predictions. Though the weighted multi‐model ensemble schemes have better skill scores in terms of ACC, the unbiased multi‐model ensemble mean provides better and more useful categorical predictions as seen from the HKS score and the economic values. Prediction skills show distinct seasonality in different regions. Precipitation prediction skill is the lowest in the Asian monsoon region in June‐July‐August. The APCN MME predictions have positive economic values in most regions and examination of monthly values suggests that the MME predictions are reasonably good and useful even with three‐month lead times. An uncalibrated multi‐model probabilistic prediction scheme gives an indication of threshold probability for which the seasonal predictions are more beneficial to users. The extreme climatic conditions are predicted well by the MME schemes. However, user sectors for which the extreme climate predictions are beneficial are different to those of regular three‐category predictions. These results can be used in planning and preparedness for the extremes of climate in the future, and when developing economic decision support models. Copyright © 2006 Royal Meteorological Society
A method of identifying and locating sea‐breeze fronts in north‐eastern Brazil by remote sensing
Authors: Planchon O. , Damato F. , Dubreuil V. , Gouery P.
Published: August 2006

A method of identifying sea‐breeze fronts by remote sensing (visible and infrared data from the GOES‐8 satellite) was applied to north‐eastern Brazil. The aim of the study was to estimate the frequency of observed sea‐breeze fronts and the average distance they penetrate inland at 1800 UTC. During the dry season (between September and December) in 2000, the highest frequency of sea‐breeze fronts was recorded on the northern fringe of the study area. The sea‐breeze fronts penetrated furthest inland between September and November, with a maximum distance from the coast at Ceará of 100 km. Copyright © 2006 John Wiley & Sons, Ltd.
Evaluating the effects of image filtering in short‐term radar rainfall forecasting for hydrological applications
Authors: Van Horne Matthew P. , Vivoni Enrique R. , Entekhabi Dara , Hoffman Ross N. , Grassotti Christopher
Published: August 2006

Radar rainfall nowcasting at short lead times has important hydrometeorological applications in the fields of weather prediction and flood forecasting. The predictability of rainfall events can vary significantly with scale as smaller storm features are less predictable than the storm envelope motion. As a result, various techniques have been developed for filtering a radar image and deriving short‐term forecasts from the more predictable, larger storm scales. In this study, the effects of image filtering on radar nowcasting performance using the Storm Tracker Nowcasting Model (STNM) are evaluated. Radar rainfall nowcasts are evaluated for three storms exhibiting varying degrees of organisation over the Arkansas‐Red River basin. In each case, it is found that the nowcast skill decreases with the forecast lead time, increases with the verification area used around a forecast location, and decreases with higher rainfall thresholds. Furthermore, it is demonstrated that a set of properly tuned filtering nowcasts are superior to simple ‘persistence’ and slightly better than ‘uniform advection’. At the scale of a large hydrologic basin (∼6000 km2), filter‐based nowcasting is shown to capture the temporal variation in rainfall amount and its spatial distribution based on a set of catchment‐based metrics. Finally, a method for relating changes in nowcasting skill to errors associated with storm dynamics not captured by image filtering techniques is evaluated. Copyright © 2006 John Wiley & Sons, Ltd.
Regulating Expression of Pyruvate Kinase in Bacillus subtilis for Control of Growth Rate and Formation of Acidic Byproducts
Authors: Pan Zhiwei , Zhu Tao , Domagalski Nathan , Khan Saleem , Koepsel Richard R. , Domach Michael M. , Ataai Mohammad M.
Published: August 2006

Our prior work has shown that a pyk mutant of Bacillus subtilis exhibited diminished acidic byproduct accumulation, dramatically elevated phosphoenolpyruvate (PEP) pool, and reduced growth rate. To determine if a low acetate‐producing but fast‐growing strain of B. subtilis could be developed, we placed the expression of the pykgene under the control of an inducible promoter. Enzyme measurements proved that PYK activity of the inducible PYK mutant (iPYK) increases with the isopropyl‐β‐d‐thiogalactopyranoside concentration. Batch growth experiments showed that growth rate and acid formation are closely related to the induction level of pyk. Measurements of cell growth rate and acetate formation of the iPYK mutant at different induction levels revealed that a PYK activity of about 12% of wild‐type allows for good growth rate (0.4 h−1 versus 0.63 h−1 of wild‐type) and low acetate production (0.26 g/L versus 1.05 g/L of wild‐type). This is the first report to our knowledge of a metabolically engineered B. subtilis strain that allows good growth rate and low acid production in batch cultures. Finally, it was found that, by varying the pyk induction level, intracellular PEP concentration can be controlled over a wide range. The intracellular PEP concentration is intimately connected to the regulation of the transport of phosphotransferase system (PTS) sugars in the presence of glucose. Because there is no other method for modulating intracellular PEP levels, this finding represents a major advance in oneapos;s ability to dissect the function of the PTS and sugar metabolism in bacteria.
Decadal variability of the air‐sea CO2 fluxes in the equatorial Pacific Ocean
Authors: Feely R. A. , Takahashi T. , Wanninkhof R. , McPhaden M. J. , Cosca C. E. , Sutherland S. C. , Carr Mary‐Elena
Published: August 2006

In order to determine the interannual and decadal changes in the air‐sea carbon fluxes of the equatorial Pacific, we developed seasonal and interannual relationships between the fugacity of CO2 (fCO2) and sea surface temperature (SST) from shipboard data that were applied to high‐resolution temperature fields deduced from satellite data to obtain high‐resolution large‐scale estimates of the regional fluxes. The data were gathered on board research ships from November 1981 through June 2004 between 95°W and 165°E. The distribution of fCO2sw during five El Niño periods and four La Niña periods were documented. Observations made during the warm boreal winter‐spring season and during the cooler boreal summer‐fall season of each year enabled us to examine the interannual and seasonal variability of the fCO2sw‐SST relationships. A linear fit through all of the data sets yields an inverse correlation between SST and fCO2sw, with both interannual and seasonal differences in slope. On average, the surface water fCO2 in the equatorial region has been increasing at a rate similar to the atmospheric CO2 increase. In addition, there appears to be a slight increase (∼27%) in the outgassing flux of CO2 after the 1997–1998 Pacific Decadal Oscillation (PDO) regime shift. Most of this flux increase is due to increase in wind speeds after the spring of 1998, although increases in fCO2sw after 1998 are also important. These increases are coincident with the recent rebound of the shallow water meridional overturning circulation in the tropical and subtropical Pacific after the regime shift.