bluuebunny/crossref_metadata_2025 huggingface dataset:
Incremental optimization in donor polymers for bulk heterojunction organic solar cells exhibiting high performance
Authors: Mayukh Mayank , Jung In Hwan , He Feng , Yu Luping
Published: June 2012

The power conversion efficiency of an organic solar cell has now exceeded the 10% mark, which is a significant improvement in the last decade. This has been made possible due to the development of low‐band‐gap polymers with tunable electron affinity, ionization potential, solubility, and miscibility with the fullerene acceptor, and the improved understanding of the factors affecting the critical device parameters such as the VOC and the JSC. This review examines the latest strategies, results, and trends that have evolved in the design of solar cells with better efficiency and durability. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012
Effects of poly(ethylene oxide) and pH on the electrospinning of whey protein isolate
Authors: Vega‐Lugo Ana‐Cristina , Lim Loong‐Tak
Published: June 2012

Poly(ethylene oxide) (PEO) is known for facilitating the electrospinning of biopolymer solutions, which are otherwise not electrospinnable. The objective of this study was to improve the understanding of the positive effects of PEO on the electrospinning of whey protein isolate (WPI) solutions under different pH conditions. Alterations in protein secondary structure and polymer solution properties (viscosity, conductivity, and dynamic surface tension), as induced by pH changes, significantly affected the electrospinning behavior of WPI/PEO (10% w/w: 0.4% w/w PEO) solutions. Acidic solutions resulted in smooth fibers (707 ± 105 nm) while neutral solutions produced spheres (2.0 ± 1.0 μm) linked with ultrafine fibers (138 ± 32 nm). In comparison, alkaline solutions produced fibers (191 ± 36 nm) that were embedded with spindle‐like beads (1.0 ± 0.5 μm). 13C NMR and FTIR spectroscopies showed that the increase in random coil and α‐helix secondary structures in WPI were the main contributors to the formation of bead‐less electrospun fibers. The electrospinning‐enabling properties of PEO on aqueous WPI solutions were attributed to physical chain entanglement between the two polymers, rather than specific polymer–polymer interactions. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012
Effects of juvenile hormone analog formulations on development and reproduction in the bed bug Cimex lectularius (Hemiptera: Cimicidae)
Authors: Goodman Mark H , Potter Michael F , Haynes Kenneth F
Published: June 2012

BACKGROUND: Bed bugs (Cimex lectularius L.) have become a common insect pest in urban areas and are often difficult to manage. Eradication is made more problematic by widespread insecticide resistance, raising interest in alternative control products. Juvenile hormone analogs (JHAs) such as methoprene and hydroprene are relatively harmless to non‐arthropods and have proved to be effective against other urban insect pests. Two JHA products (Gentrol® and Precor®, Central Life Sciences, Schaumburg, IL) were tested for efficacy against various bed bug stages as direct spray and as dry residue using three bed bug strains.

RESULTS: At 1× and 2× the label rate, Precor® [active ingredient (S)‐methoprene] had no significant effect on the development or fecundity of bed bugs. At 2× the label rate, confinement to residues of Gentrol® [active ingredient (S)‐hydroprene] had no significant effect, but residues at 3× and 10× the label rate caused a reduction in fecundity and impaired development. Field strains were more susceptible to the reproductive effects of (S)‐hydroprene than a long‐maintained laboratory strain.

CONCLUSIONS: While JHAs are attractive alternatives for pest management because of their inherent safety and distinct mode of action, these JHA formulations would have little impact on bed bug populations without relabeling to allow for higher application rates. Copyright © 2012 Society of Chemical Industry
A Home to Plan the First Child? Fertility Intentions and Housing Conditions in Italy
Authors: Vignoli Daniele , Rinesi Francesca , Mussino Eleonora
Published: June 2012

In Italy, the existing literature on the link between low fertility and people's socio‐economic status has been surprisingly silent about the potential role of housing. This study aimed at filling this gap. Are Italians who are better off in terms of housing security more likely to plan to have a first child in the short run? Our results suggest that there is a clear positive gradient between the fertility intentions of couples and the degree to which they feel secure about their housing situation. The positive gradient remained substantial after we controlled for the demographic and socio‐economic characteristics of the couple and after we adjusted the estimates for the presence of unobserved characteristics and we took into account the endogeneity between housing and fertility. This implies that, in Italy, the housing dimension should not be disregarded when studying fertility differentials. Copyright © 2012 John Wiley & Sons, Ltd.
On a general definition of the squared Brunt–Väisälä frequency associated with the specific moist entropy potential temperature
Authors: Marquet Pascal , Geleyn Jean‐François
Published: June 2012

The squared Brunt–Väisälä frequency (BVF) is computed in terms of the moist entropy potential temperature recently defined by Marquet (2011.Q. J. R. Meteorol. Soc.137: 768–791). Both homogeneously saturated and non‐saturated versions ofN2(the squared BVF) are derived. The method employed for computing these special homogeneous cases relies on the expression of density written as a function of pressure, total water content and specific moist entropy only. The associated conservative variable diagrams are discussed and compared with existing ones. Despite being obtained without any simplification, the formulations forN2remain nicely compact and are clearly linked with the squared BVF expressed in terms of the adiabatic non‐saturated and saturated lapse rates. As in previous similar expressions, the extreme homogeneous solutions forN2are of course different, but they are not analytically discontinuous. This allows us to define a simple bridging expression for a single general shape ofN2, depending only on the basic mean atmospheric quantities and on a transition parameter, to be defined (or parametrized) in connection with the type of application sought. This integrated result remains a linear combination (with complex but purely local weights) of two terms only, namely the environmental gradient of the moist entropy potential temperature and the environmental gradient of the total water content. Simplified versions of the various equations are also proposed for the case in which the moist entropy potential temperature is approximated by a function of both so‐called moist conservative variables of Betts. Copyright © 2012 Royal Meteorological Society
Contrasting aerosol characteristics and radiative forcing over Hyderabad, India due to seasonal mesoscale and synoptic‐scale processes
Authors: Sinha P. R. , Dumka U. C. , Manchanda R. K. , Kaskaoutis D. G. , Sreenivasan S. , Krishna Moorthy K. , Suresh Babu S.
Published: June 2012

Regular measurements of spectral Aerosol Optical Depth (AOD) at ten wavelengths, obtained from multi‐wavelength radiometer (MWR) under cloudless conditions in the outskirts of the tropical urban region of Hyderabad, India for the period January 2008 to December 2009, are examined. In general, high AOD with a coarse‐mode abundance is seen during the pre‐monsoon (March to May) and summer monsoon (June to September) with flat AOD spectra and low Ångström wavelength exponent (α), while in post‐monsoon (October–November) and winter (December–February) seasons, fine‐mode dominance and steep AOD spectra are the basic features. The aerosol columnar size distribution (CSD) retrieved from the spectral AOD using King's inversion showed bimodal size distributions for all the seasons, except for the monsoon, with an accumulation‐mode radius at 0.12–0.25 µm and a coarse‐mode one at 0.86–1.30 µm. On the other hand, the CSD during the monsoon follows the power law for fine mode and the unimodal distribution for coarse mode. The fine‐mode aerosols during post‐monsoon and winter appear to be associated with air masses from continental India, while the coarse‐mode particles during pre‐monsoon and monsoon with air masses originating from west Asia and western India. The single‐scattering albedo (SSA) calculated using the OPAC model varied from 0.83 ± 0.05 in winter to 0.91 ± 0.01 during the monsoon, indicating significant absorption by aerosols due to larger black carbon mixing ratio in winter, whereas a significant contribution of sea‐salt in the monsoon season leads to higher SSAs. Aerosol radiative forcing (ARF) calculated using SBDART shows pronounced monthly variability at the surface, top of atmosphere (TOA) and within the atmosphere due to large variations in AOD and SSA. In general, larger negative ARF values at the surface (−65 to −80 W m−2) and TOA (∼−17 W m−2) are observed during the pre‐monsoon and early monsoon, while the atmospheric heating is higher (∼50–70 W m−2) during January‐April resulting in heating rates of ∼1.6–2.0 K day−1. Copyright © 2012 Royal Meteorological Society
Perils of categorical thinking: “Oxic/anoxic” conceptual model in environmental remediation
Authors: Bradley Paul M.
Published: June 2012

Given ambient atmospheric oxygen concentrations of about 21 percent (by volume), the lower limit for reliable quantitation of dissolved oxygen concentrations in groundwater samples is in the range of 0.1–0.5 mg/L. Frameworks for assessing in situ redox condition are often applied using a simple two‐category (oxic/anoxic) model of oxygen condition. The “oxic” category defines the environmental range in which dissolved oxygen concentrations are clearly expected to impact contaminant biodegradation, either by supporting aerobic biodegradation of electron‐donor contaminants like petroleum hydrocarbons or by inhibiting anaerobic biodegradation of electron‐acceptor contaminants like chloroethenes. The tendency to label the second category “anoxic” leads to an invalid assumption that oxygen is insignificant when, in fact, the dissolved oxygen concentration is less than detection but otherwise unknown. Expressing dissolved oxygen concentrations as numbers of molecules per volume, dissolved oxygen concentrations that fall below the 0.1 mg/L field detection limit range from 1 to 1017 molecules/L. In light of recent demonstrations of substantial oxygen‐linked biodegradation of chloroethene contaminants at dissolved oxygen concentrations well below the 0.1–0.5 mg/L field detection limit, characterizing “less than detection” oxygen concentrations as “insignificant” is invalid. © 2012 Wiley Periodicals, Inc.
Sustainable wind‐driven bioventing at a petroleum hydrocarbon–impacted site
Authors: Dominguez Ryan C. , Leu Jim , Bettahar Mehdi
Published: June 2012

Bioventing—the injection of air into the vadose zone to increase microbial activity—is a commonly used, proven technology for remediating volatile organic compounds present in the vadose zone. Passive systems driven by wind or solar power are both more cost‐effective and sustainable than conventional systems. Such a passive system is being applied successfully to remediate a site impacted with total petroleum hydrocarbons (TPH) and benzene, toluene, ethylbenzene, and xylenes (BTEX) in soil. Bioventing technology was approved by the regulatory agency as an interim remedial action to remove chemicals of concern (COCs) in the vadose zone. A bioventing pilot study was conducted to evaluate the effectiveness of COC removal and collect parameters for full‐scale design and implementation. To evaluate the potential to use wind‐driven bioventing technology, two mobile weather stations were installed at the site and monitored for one month for a wind speed study. Based on the pilot‐test data and wind speed research, 12‐inch diameter funnel/vane 360‐degree wind collectors were designed as passive wind‐driven air‐injection devices and connected to existing monitoring wells. The measured air velocity ranged from 20 to 110 feet per minute during the start‐up and the first three months of operation and maintenance. Monitoring indicated a 20 percent oxygen delivery and greater than 90 percent reduction in COC concentrations, demonstrating a successful sustainable remediation with no power requirement and minimal operation and maintenance. © 2012 Wiley Periodicals, Inc.
Literature review: Electrodialytic remediation and potential environmental applications of oil fly ash
Authors: Kuzniewski Saleha
Published: June 2012

Oil fly ash (OFA) contains environmentally toxic heavy metal and substituted polycyclic aromatic hydrocarbons. This review discusses the physical and chemical properties of OFA and presents information from other types of fly ash that can be used as concepts for the remediation and uses of OFA. Electrokinetic remediation is useful to remove some of the heavy metals for broader uses of the fly ash in agriculture, for making construction material, for contaminated wastewater treatment, and also for carbon dioxide sequestration. This review can be useful to develop approaches for the remediation and environmental management of OFA. © 2012 Wiley Periodicals, Inc.
How firms learn heuristics: Uncovering missing components of organizational learning
Authors: Bingham Christopher B. , Haleblian Jerayr (John)
Published: June 2012

This study explores how firms learn heuristics from negative outcomes. Prior literature has suggested that learning is strongly affected by whether attributions for negative outcomes are internal or external. Our data complement this view by revealing a new and different pattern. Specifically, they show that learning heuristics appears more dependent on whether attributions are convergent or divergent across hierarchical levels. Moreover, our data show that formal communication influences the convergence and divergence of those attributions. Besides setting forth an emergent framework for how firms learn heuristics and shedding light on the microfoundations of dynamic capabilities, a central contribution of this article is uncovering important missing components of organizational learning. Copyright © 2012 Strategic Management Society.
Queue‐based congestion detection and multistage rate control in event‐driven wireless sensor networks
Authors: Liang Lulu , Gao Deyun , Leung Victor C.M.
Published: June 2012

Protocols for sensor networks have traditionally been designed using the best effort delivery model. However, there are many specific applications that need reliable transmissions. In event‐driven wireless sensor networks, the occurrence of an event may generate a large amount of data in a very short time. Among them, some critical urgent information needs to be transmitted reliably in a timely manner. In this scenario, congestion is inevitable because of the constraints in available resources. How to control the congestion is very important for the reliable transmission of urgent information. To address this problem, we propose a queue‐based congestion detection and a multistage rate control mechanism. In our proposed mechanism, not only the current queue length but also the queue fluctuation are adopted as indications of congestion. Each sensor node evaluates its congestion level locally and determines its congestion state with a state machine. We design a multistage rate adjustment mechanism for nodes to adjust their rates depending on their congestion states. We also distinguish high‐priority critical traffic from low‐priority non‐critical traffic. Extensive simulation results confirm the superior performance of our proposed protocol with respect to throughput, loss probability, and delay.Copyright © 2012 John Wiley & Sons, Ltd.
Delay‐insensitive identification of neighbors using unslotted and slotted protocols
Authors: Shafiul Azam Howlader Md. , Frater Michael R. , Ryan Michael J.
Published: June 2012

For many applications, it is desirable for a node to be able to identify the neighbor nodes currently within range. However, the identification procedures for terrestrial communication networks (TCNs) are inefficient when implemented in long‐delay networks (LDNs) such as underwater acoustic networks or satellite networks, where the propagation time of a packet cannot be neglected. Here, we propose a time‐efficient and power‐efficient procedure, which is insensitive to propagation delay, for identifying neighbors in an LDN by optimizing the network offered load using either unslotted or slotted protocols. The procedure is adapted to the scenario when node cardinality and distribution are either known or unknown in advance. We achieve improvements as high as 80% in time and 45% in power consumption for our proposed approach compared with approaches developed previously for TCN. Furthermore, we analyze our proposed approach with the inclusion of the capture effect and packet receive time variations. We also provide a closed form formula for finding the optimum guard time and a procedure to estimate the packet receive time variations. Copyright © 2012 John Wiley & Sons, Ltd.
Applications of network coding to improve TCP performance over wireless mesh networks: a survey
Authors: Arianpoo Nasim , Jokar Paria , Leung Victor C.M.
Published: June 2012

There is growing interest in the use of wireless mesh network (WMN) as a last‐mile option for Internet access. Despite the many benefits of WMNs, the performance of Internet access may not be ideal. One of the main issues is the interaction of transmission control protocol (TCP) with the underlying network. The poor performance of TCP over multi‐hop networks is well‐documented, and extensive research exists, which addresses TCPs foible and enhance TCP performance for multi‐hop environments. This paper provides a thorough survey of TCP performance issues over WMNs and the available solutions to address these issues. Among the existing methods, we focused on network coding (NC) and the ways that TCP interacts with network coded systems. NC is a technique that encodes the received packets in each node before forwarding them towards the destination. The use of NC in the transport layer to address performance issues raised by wireless access is a recent research topic. This paper presents a detailed study of TCP interaction with NC. Some open research areas in this field are suggested. Copyright © 2012 John Wiley & Sons, Ltd.
Lipid‐based liquid biofuels from autotrophic microalgae: energetic and environmental performance
Authors: Reijnders Lucas
Published: June 2012

Commercial cultivation of autotrophic microalgae for food production dates back to the 1950s. Autotrophic microalgae have also been proposed as a source for lipid‐based liquid biofuels. As yet, there is no commercial production of such biofuels and estimated near‐term prices are far in excess of fossil fuel prices and prices of biofuels based on terrestrial food oil crops. Future costs of autotrophic microalgal lipid‐based biofuels are very uncertain. The energetic return of energy investment in liquid autotrophic microalgal biofuels is below a factor 5, even if optimistic assumptions are made about future technologies. Available studies do not allow for firm estimates of life cycle greenhouse gas emissions of autotrophic microalgal lipid‐based biofuels. Apart from greenhouse gases, life cycle pollutant emissions of autotrophic microalgal biodiesel may well be more of an environmental burden than the life cycle pollutant emissions linked to fossil diesel or biofuels based on canola or switchgrass. Whether the prospects for, and performance of, lipid‐based biofuels from autotrophic microalgae in the more distant future will much improve appears to be largely dependent on breakthroughs in production technology which may, or may not, occur.

This article is categorized under:

Bioenergy > Science and Materials
Pyroelectric X‐ray application to X‐ray absorption and emission spectroscopies
Authors: Kawai Jun , Ishii Hideshi , Ida Hiroyuki
Published: June 2012

Pyroelectric X‐ray generator of Amptek Inc. was used for X‐ray absorption spectroscopy as well as X‐ray fluorescence analysis. The white X‐ray radiation from the pyroelectric crystal was used for X‐ray absorption measurement by using an Si‐PIN X‐ray detector. X‐ray absorption K‐edge spectra of transition metal thin films could be measured. The X‐ray fluorescence analysis was possible down to 0.1 ppm concentrations of transition metal water solutions after preconcentrations. The electric battery‐driven pyroelectric X‐ray generator was possible for practical chemical analysis. Copyright © 2012 John Wiley & Sons, Ltd.
Trauma Care in Africa: A Status Report From Botswana, Guided by the World Health Organization’s “Guidelines for Essential Trauma Care”
Authors: Hanche‐Olsen Terje Peder , Alemu Lulseged , Viste Asgaut , Wisborg Torben , Hansen Kari S.
Published: June 2012

Background

Trauma represents a significant and increasing challenge to health care systems all over the world. This study aimed to evaluate the trauma care capabilities of Botswana, a middle‐income African country, by applying the World Health Organization’s Guidelines for Essential Trauma Care.

Methods

All 27 government (16 primary, 9 district, 2 referral) hospitals were surveyed. A questionnaire and checklist, based on “Guidelines for Essential Trauma Care” and locally adapted, were developed as situation analysis tools. The questionnaire assessed local trauma organization, capacity, and the presence of quality improvement activity. The checklist assessed physical availability of equipment and timely availability of trauma‐related skills. Information was collected by interviews with hospital administrators, key personnel within trauma care, and through on‐site physical inspection.

Results

Hospitals in Botswana are reasonably well supplied with human and physical resources for trauma care, although deficiencies were noted. At the primary and district levels, both capacity and equipment for airway/breathing management and vascular access was limited. Trauma administrative functions were largely absent at all levels. No hospital in Botswana had any plans for trauma education, separate from or incorporated into other improvement activities. Team organization was nonexistent, and training activities in the emergency room were limited.

Conclusions

This study draws a picture of trauma care capabilities of an entire African country. Despite good organizational structures, Botswana has room for substantial improvement. Administrative functions, training, and human and physical resources could be improved. By applying the guidelines, this study creates an objective foundation for improved trauma care in Botswana.
Biliary tract carcinoma: clinical perspectives on molecular targeting strategies for therapeutic options
Authors: Shoda Junichi , Ishige Kazunori , Sugiyama Hiroaki , Kawamoto Toru
Published: June 2012

Biliary tract carcinoma (BTC) is a lethal malignancy. This lethality is essentially attributed to both slow carcinogenesis occurring under complex pathological circumstances and to the asymptomatic growth of BTC infiltrating the surrounding structures by varying routes. The disease is therefore usually detected at an advanced stage with a high frequency of distant organ metastasis. To date, conventional chemotherapy and radiation therapy have been notably ineffective against BTC. For an improved treatment outcome of BTC and prolonged survival, there is now a real and urgent need to focus on developing novel and potent therapeutic strategies aimed at exploiting select molecular targets associated with tumor proliferation, invasion, and/or metastasis that would impact in a significant way on clinical outcome. The outcomes of recent studies, by the analysis of BTC cells, BTC animal models, and clinical specimens of BTC patients, have revealed, in detail, the molecular mechanism of carcinogenesis and tumor progression of BTC, and these studies have exploited select molecular targets that could significantly impact the clinical outcome. In the near future, the development of new molecular targeting drugs with potent efficacy against BTC, and the performance of randomized clinical trials of these drugs are urgent and essential for the treatment of patients with BTC.
En Bloc Excision of Thoracic Paraspinal Synovial Sarcoma with Subtotal Spondylectomy
Authors: Diane Tai Hei-Yan , Ka-Kin Li , Ying-Lee Lam
Published: June 2012

We report a case of thoracic paraspinal synovial sarcoma in a 52-year-old man. It was treated with en bloc excision, subtotal spondylectomy, spinal and soft tissue reconstruction. The surgical technique, the approach of multilevel spinal osteotomy and literature review of this rare paraspinal tumour are discussed.
Energy dissipation and the contact-line region of a spreading bridge
Authors: van Lengerich H. B. , Steen P. H.
Published: June 2012

A drop on a circular support spontaneously spreads upon contact with a substrate. The motion is driven by a loss of surface energy. The loss of recoverable energy can be expressed alternatively as work done at the liquid–gas interface or dissipation through viscosity and sliding friction. In this paper we require consistency with the energy lost by dissipation in order to infer details of the contact-line region through simulations. Simulations with the boundary integral method are used to compute the flow field of a corresponding experiment where polydimethylsiloxane spreads on a relatively hydrophobic surface. The flow field is used to calculate the energy dissipation, from which slip lengths for local slip and Navier slip boundary conditions are found. Velocities, shear rates and pressures along the interface as well as interface shapes in the microscopic region of the contact line are also reported. Angles, slip length and viscous bending length scale allow a test of the Voinov–Hocking–Cox model without free parameters.
Numerical investigation of turbulent supersonic axisymmetric wakes
Authors: Sandberg Richard D.
Published: June 2012

Numerical experiments are conducted of turbulent supersonic axisymmetric wakes at Mach number $M= 2. 46$ and Reynolds number, based on free-stream velocity and base diameter, ${\mathit{Re}}_{D} = 1\ensuremath{\times} 1{0}^{5} $. Direct numerical simulations (DNS) are used to study the effect of approach flow conditions, and of specific azimuthal modes, on the near-wake behaviour. To that end, DNS are performed with laminar and turbulent approach boundary layers, and additional turbulent approach flow DNS with reduced circumferential size are conducted to deliberately eliminate certain azimuthal/helical modes. DNS with turbulent approach flow show an increased turning angle and increased growth of the separating shear layer, leading to a shorter recirculation region, a stronger recompression shock system, and ultimately good agreement with experimental data at considerably higher Reynolds number. A similar wake structure is found for laminar and turbulent inflow conditions, giving further evidence of the wake structure being a consequence of the global near-wake instabilities and not a result of upstream conditions. Stability analyses of two-dimensional basic states are carried out by computing the temporal pulse response using forced Navier–Stokes simulations to investigate which azimuthal modes are dominant for fully turbulent wakes and how the stability behaviour is influenced by the choice of basic state. Using the time- and azimuthally averaged data from three-dimensional DNS with turbulent inflow as basic state, an absolute instability of the axisymmetric mode was found and helical modes $m= 4, 5, 6$ were found to be linearly most unstable, in contrast to results obtained earlier using an axisymmetric flow solution as the basic state. The addition of a turbulence viscosity in the forced DNS retains most of the stability characteristics but reduces the wavenumber of the linearly most-amplified modes.
TOTALLY NULL SETS FOR A(X)
Authors: BOOS LYNETTE J.
Published: June 2012

For a compact subset K of the boundary of a compact Hausdorff space X, six properties that K may have in relation to the algebra A(X) are considered. It is shown that in relation to the algebra A(Dn), where Dn denotes the n-dimensional polydisc, the property of being totally null is weaker than the other five properties. A general condition is given on the algebra A(X) which implies the existence of a totally null set that is not null, and several conditions are stated for A(X) , each of which is sufficient for a totally null set to be a null set.
CRITICAL CURVES FOR A COUPLED SYSTEM OF FAST DIFFUSIVE NEWTONIAN FILTRATION EQUATIONS
Authors: DU RUNMEI , WANG ZEJIA
Published: June 2012

This paper deals with the large-time behaviour of solutions to the fast diffusive Newtonian filtration equations coupled via the nonlinear boundary sources. A result of Fujita type is obtained by constructing various kinds of upper and lower solutions. In particular, it is shown that the critical global existence curve and the critical Fujita curve concide for the multi-dimensional system. This is quite different from the known results obtained in Wang, Zhou and Lou [‘Critical exponents for porous medium systems coupled via nonlinear boundary flux’, Nonlinear Anal.7(1) (2009), 2134–2140] for the corresponding one-dimensional problem.
GENERATING SYSTEMS OF SUBGROUPS IN SU(2, 1)
Authors: FU XI , LI LIULAN
Published: June 2012

LetG⊂SU(2,1) be nonelementary andSbe its minimal generating system. In this paper, we show that ifSsatisfies some conditions, thenScan be replaced by a minimal generating systemS1consisting only of loxodromic elements.
A NOTE CONCERNING THE DISTANCES OF UNIFORMLY DISTRIBUTED POINTS FROM THE CENTRE OF A RECTANGLE
Authors: STEWART ROBERT , ZHANG HONG
Published: June 2012

Given a rectangle containing uniformly distributed random points, how far are the points from the rectangle’s centre? In this paper we provide closed-form expressions for the cumulative distribution function and probability density function that characterise the distance. An expression for the average distance to the centre of the rectangle is also provided.
NAKAYAMA AUTOMORPHISMS OF FROBENIUS CELLULAR ALGEBRAS
Authors: LI YANBO
Published: June 2012

Let A be a finite-dimensional Frobenius cellular algebra with cell datum (Λ,M,C,i). Take a nondegenerate bilinear form f on A. In this paper, we study the relationship among i, f and a certain Nakayama automorphism α. In particular, we prove that the matrix associated with α with respect to the cellular basis is uni-triangular under a certain condition.
A review of the potential mechanisms for the lowering of colorectal oncogenesis by butyrate
Authors: Fung Kim Y. C. , Cosgrove Leah , Lockett Trevor , Head Richard , Topping David L.
Published: June 2012

Colorectal cancer (CRC) is a leading cause of preventable cancer deaths worldwide, with dietary factors being recognised as key risk modifiers. Foods containing dietary fibre are protective to a degree that the World Cancer Research Fund classifies the evidence supporting their consumption as ‘convincing’. The mechanisms by which fibre components protect against CRC remain poorly understood, especially their interactions with the gut microbiome. Fibre is a composite of indigestible plant polysaccharides and it is emerging that fermentable fibres, including resistant starch (RS), are particularly important. RS fermentation induces SCFA production, in particular, relatively high butyrate levels, andin vitrostudies have shown that this acid has strong anti-tumorigenic properties. Butyrate inhibits proliferation and induces apoptosis of CRC cell lines at physiological concentrations. These effects are attributed to butyrate's ability to alter gene transcription by inhibiting histone deacetylase activity. However, the more recent discovery of G-protein coupled receptors that bind butyrate and other SCFA and data obtained from proteomic and genomic experiments suggest that alternative pathways are involved. Here, we review the mechanisms involved in butyrate-induced apoptosis in CRC cells and, additionally, the potential role this SCFA may play in mediating key processes in tumorigenesis including genomic instability, inflammation and cell energy metabolism. This discussion may help to inform the development of strategies to lower CRC risk at the individual and population levels.
Body iron is associated with cognitive executive planning function in college women
Authors: Blanton Cynthia A. , Green Michael W. , Kretsch Mary J.
Published: June 2012

Evidence of the relationship between altered cognitive function and depleted Fe status is accumulating in women of reproductive age but the degree of Fe deficiency associated with negative neuropsychological outcomes needs to be delineated. Data are limited regarding this relationship in university women in whom optimal cognitive function is critical to academic success. The aim of the present study was to examine the relationship between body Fe, in the absence of Fe-deficiency anaemia, and neuropsychological function in young college women. Healthy, non-anaemic undergraduate women (n 42) provided a blood sample and completed a standardised cognitive test battery consisting of one manual (Tower of London (TOL), a measure of central executive function) and five computerised (Bakan vigilance task, mental rotation, simple reaction time, immediate word recall and two-finger tapping) tasks. Women's body Fe ranged from − 4·2 to 8·1 mg/kg. General linear model ANOVA revealed a significant effect of body Fe on TOL planning time (P= 0·002). Spearman's correlation coefficients showed a significant inverse relationship between body Fe and TOL planning time for move categories 4 (r − 0·39, P= 0·01) and 5 (r − 0·47, P= 0·002). Performance on the computerised cognitive tasks was not affected by body Fe level. These findings suggest that Fe status in the absence of anaemia is positively associated with central executive function in otherwise healthy college women.
Seasonal variation of natural mortality factors of the guava psyllidTriozoida limbata
Authors: Semeão A.A. , Martins J.C. , Picanço M.C. , Chediak M. , da Silva E.M. , Silva G.A.
Published: June 2012

It is important to understand how components of the agroecosystem interfere with the attack of a pest species and their seasonality in order to use these components in IPM programs. This study focused on the evaluation of the seasonality of natural control factors associated with the guava psyllidTriozoida limbata(Enderlein) in Brazil. Life-table data were collected from an experimental guava orchard during four periods that roughly represented four seasons. Natural mortality was monitored daily through the immature stages, and the relative importance of each natural mortality factor and its seasonality was determined. Significant statistical differences were observed in the mortality during the four periods (P < 0.05). Several factors contributed to the mortality ofT. limbata, including rainfall, physiological disturbance, the parasitoidPsyllaephagussp. (Hymenoptera: Encyrtidae) and specific predators: syrphids, predatory wasps and other generalist predators. Depending on the location of nymphs (exposed or inside galls), the relative importance of the different natural mortality factors changed. The principal component analysis (PCA) showed some trends in the relationship of natural control agents and weather conditions. For example, the occurrence of predatory wasps was positively correlated with temperature and occurrence of winds; the occurrence of syrphids andPsyllaephagussp. were negatively correlated with temperature and winds; and the occurrence of other generalist predators were negatively correlated with the occurrence of rainfall and photoperiod. The results showed the importance of natural mortality factors for the management ofT. limbataand their changes through the different seasons which should be considered when implementing IPM programs in guava orchards.
COMMUNITY PSYCHOLOGICAL STRESSOR-INDUCED SECONDARY SEX RATIO DECLINE AFTER A SEISMIC SEQUENCE IN THE GREEK ISLAND OF ZAKYNTHOS
Authors: TOURIKIS JOHN D. , BERATIS ION N.
Published: June 2012

The secondary sex ratio (the ratio of boys to girls at birth) may demonstrate a decline following community stress-inducing major destructive events. This study aims to investigate whether or not moderate adverse life events, in conjunction with endogenous psychological characteristics, can induce sufficient community stress to affect the sex ratio. From April 3rd to May 8th 2006 a moderate sized earthquake sequence occurred offshore the Greek island of Zakynthos, which had been hit by a destructive earthquake half a century earlier. The monthly sex ratio after the earthquake sequence was estimated and compared with that of previous and following years. Eleven months after the onset of the earthquakes the sex ratio fell to 1.000, and during the next two months (March and April) it declined further to 0.612. The sex ratio one year before its decline was 1.158 and over a total 6-year period, 3 years before and 3 years after the sequence, it was 1.063; the March–April decline in male births is significant (OR=0.53, 95% CI=0.32–0.86,p=0.013, and OR=0.57, 95% CI=0.36–0.91,p=0.023, respectively). Also, the number of boys relative to girls in March–April 2007 was significantly lower than during the same months 3 years before and after the sequence (OR=0.50, 95% CI=0.31–0.82,p=0.007). The findings suggest that basic biological characteristics, such as the sex ratio, can be affected by psychological stressors interwoven with the pertaining psychology of the population.
Risk factors for intramammary infections and subclinical mastitis in post-partum dairy heifers
Authors: Krömker Volker , Pfannenschmidt Florian , Helmke Katherina , Andersson Robby , Grabowski Nils T.
Published: June 2012

The prevalence of intramammary infections (IMI) and subclinical mastitis (SCM) in 436 German Holstein heifers was put in relation with clinical findings of the udder and data regarding individual rearing and housing conditions of the animals. The clinical examination took place on the day of the livestock auction (at approximately 41 d in milk, DIM). On that day, 31% of the heifers had IMI in at least one quarter, and 18% of all quarters were infected. Coagulase-negative staphylococci were the most prevalent bacteria isolated, accounting for 68% of the positive samples. Data were analysed by logistic regression. Criteria such as ‘juvenile intersucking’, ‘teats shorter than 35 mm’, ‘teats with a diameter <18 mm’ and ‘udder oedema at the day of the auction’ were associated with IMI in heifers during the first 41 DIM. Loose-housing systems during pregnancy (as opposed to tie-stalls), juvenile intersucking, clinical mastitis during the first week after calving, teat diameters <18 mm, and employing organic bedding material in the stables before calving were associated with subclinical mastitis.
Loss Allocation in Securitization Transactions
Authors: Franke Günter , Herrmann Markus , Weber Thomas
Published: June 2012

This paper analyzes the loss allocation to first, second, and third loss positions in European collateralized debt obligation transactions. The quality of the underlying asset pool plays a predominant role for the loss allocation. A lower asset pool quality induces the originator to take a higher first loss position, but, in a synthetic transaction, a smaller third loss position. The share of expected default losses, borne by the first loss position, is largely independent of asset pool quality but lower in securitizations of corporate loans than in those of corporate bonds. Originators with a good rating and low Tobin’s Q prefer synthetic transactions.
To Rule a Ferocious Province: Roman Policy and the Aftermath of the Boudican Revolt
Authors: Gambash Gil
Published: June 2012

Official Roman action in the aftermath of the Boudican revolt is shown in this article to reveal a strong, persistent intention to allay local anger. Under consideration are such aspects as the Roman policy of official appointments in the region, the deployment of military forces, and the commemoration of the victory over the rebel forces. The conclusion reached takes issue with the widely prevailing view that Roman governance based itself mostly on oppressive measures.
Insights and principles for supporting social engagement in rural older people
Authors: WALKER J. , ORPIN P. , BAYNES H. , STRATFORD E. , BOYER K. , MAHJOURI N. , PATTERSON C. , ROBINSON A. , CARTY J.
Published: June 2012

Staying socially engaged is known to improve health and longevity in older people. As the population ages, maintaining levels of social engagement among older people becomes increasingly important. Nevertheless, advancing age brings with it many challenges to social engagement, especially in rural areas. A three-year Australian Research Council Linkage Project sought to improve understandings of age-related triggers to social disengagement in six Tasmanian communities that are representative of rural Australian experience, and thus of wider salience. A collaboration between academics and health and social professionals, the project investigated design solutions for service frameworks that may be useful before ageing individuals become isolated and dependent, and that may support those individuals to actively contribute to and benefit from social life. The purpose of this paper is to report on perspectives about diminishing levels of social engagement held by older rural participants and service providers, and to advance a number of key insights on ways in which to nurture social engagement and improve the experience of ageing.
For the generation of an intense isolated pulse in hard X-ray region using X-ray free electron laser
Authors: Kumar Sandeep , Kang Heung-Sik , Kim Dong-Eon
Published: June 2012

For a real, meaningful pump-probe experiment with attosecond temporal resolution, an intense isolated attosecond pulse is in demand. For that purpose we report the generation of an intense isolated attosecond pulse, especially in X-ray region using a current-enhanced self-amplified spontaneous emission in a free electron laser (FEL). We use a few cycle laser pulse to manipulate the electron-bunch inside a two-period planar wiggler. In our study, we employ the electron beam parameters of Pohang Accelerator Laboratory (PAL)-XFEL. The RF phase effect of accelerator columns on the longitudinal energy distribution profile and current profile of electron-bunch is also studied, aiming that these results can be experimentally realized in PAL-XFEL. We show indeed that the manipulation of electron-energy bunch profile may lead to the generation of an isolated attosecond hard X-ray pulse: 150 attosecond radiation pulse at 0.1 nm wavelength can be generated.
A Methodology for tele-operating mobile manipulators with an emphasis on operator ease of use
Authors: Frejek M. , Nokleby S. B.
Published: June 2012

An algorithm for the tele-operation of mobile-manipulator systems with a focus on ease of use for the operator is presented. The algorithm allows for unified, intuitive, and coordinated control of mobile manipulators. It consists of three states. In the first state, a single 6-degrees-of-freedom (DOF) joystick is used to control the manipulator's position and orientation. The second state occurs when the manipulator approaches a singular configuration, resulting in the mobile base moving in a manner so as to keep the end-effector travelling in its last direction of motion. This is done through the use of a constrained optimization routine. The third state is entered when the operator returns the joystick to the home position. Both the mobile base and manipulator move with respect to one another keeping the end-effector stationary and placing the manipulator into an ideal configuration. The algorithm has been implemented on an 8-DOF mobile manipulator and the test results show that it is effective at moving the system in an intuitive manner.
The -spectrum and the -functional calculus
Authors: Colombo Fabrizio , Sabadini Irene
Published: June 2012

In some recent papers (called $\mathcal{S}$-functional calculus) for n-tuples of both bounded and unbounded not-necessarily commuting operators. The $\mathcal{S}$-functional calculus is based on the notion of $\mathcal{S}$-spectrum, which naturally arises from the definition of the $\mathcal{S}$-resolvent operator for n-tuples of operators. The $\mathcal{S}$-resolvent operator plays the same role as the usual resolvent operator for the Riesz–Dunford functional calculus, which is associated to a complex operator acting on a Banach space. When one considers commuting operators (bounded or unbounded) there is the possibility of simplifying the computation of the $\mathcal{S}$-spectrum. In fact, in this case we can use the F-spectrum, which is easier to compute than the $\mathcal{S}$-spectrum. In the case of commuting operators, our functional calculus is based on the $\mathcal{F}$-spectrum and will be called $\mathcal{SC}$-functional calculus. We point out that for a correct definition of the $\mathcal{S}$-resolvent operator and of the $\mathcal{SC}$-resolvent operator in the unbounded case we have to face different extension problems. Another reason for a more detailed study of the $\mathcal{F}$-spectrum is that it is related to the $\mathcal{F}$-functional calculus which is based on the integral version of the Fueter mapping theorem. This functional calculus is associated to monogenic functions constructed by starting from slice monogenic functions.
Derivation of the nonlinear bending–torsion model for a junction of elastic rods
Authors: Tambača Josip , Velčić Igor
Published: June 2012

We derive the one-dimensional bending–torsion equilibrium model for the junction of straight rods. The starting point is a three-dimensional nonlinear elasticity equilibrium problem written as a minimization problem for a union of thin, rod-like bodies. By taking the limit as the thickness of the three-dimensional rods tends to zero, and by using ideas from the theory of Γ-convergence, we find that the resulting model consists of the union of the usual one-dimensional nonlinear bending–torsion rod models which satisfy the following transmission conditions at the junction point: continuity of displacement and rotation of the cross-sections; balance of contact forces and contact couples.
On singular quasi-monotone (p, q)-Laplacian systems
Authors: Manouni Said El , Perera Kanishka , Shivaji Ratnasingham
Published: June 2012

We combine the sub- and supersolution method and perturbation arguments to obtain positive solutions of singular quasi-monotone (p, q)-Laplacian systems.
Blow-up phenomena in parabolic problems with time-dependent coefficients under Neumann boundary conditions
Authors: Payne L. E. , Philippin G. A.
Published: June 2012

This paper deals with the blow-up of solutions to a class of parabolic problems with time-dependent coefficients under homogeneous Neumann boundary conditions. For one set of problems in this class we show that no global solution can exist. For another we derive lower bounds for the time of blow-up when blow-up occurs.