bluuebunny/crossref_metadata_2025 huggingface dataset:
Drop test simulation of a sample tomato with finite element method
Authors: Kabas Onder , Celik H Kursat , Ozmerzi Aziz , Akinci İbrahin
Published: May 2008

BACKGROUND: The aim of this study was to investigate deformation behaviour of a biological material upon crashing. The 50 samples for the study were randomly selected from harvested tomatoes.

RESULT: Mechanical parameters were obtained by a compression test of the chosen cherry tomato samples. The behaviour of the drop characteristics of cherry tomato was investigated using finite element simulation, and deformation characteristics were determined by a combination of the finite element results and measured data. A comparison between experimental data and finite element simulation shows that the two sets of results agree well.

CONCLUSION: The results of this study provide the foundation for further investigations of the mechanical parameters of fruits and vegetables by using finite element simulations. Copyright © 2008 Society of Chemical Industry
Explicit analytical solutions of the generalized Burger and Burger–Fisher equations by homotopy perturbation method
Authors: Rashidi M.M. , Ganji D.D. , Dinarvand S.
Published: May 2008

In this article, we apply the homotopy perturbation method (HPM) to obtain approximate analytical solutions of the generalized Burger and Burger‐Fisher (B–F) equations. Several numerical examples are given to illustrate the efficiency of the HPM. Comparison of the result obtained by the present method with exact solution reveals that the accuracy and fast convergence of the new method. It is predicted that the HPM can be found wide application in engineering problems. © 2008 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2009
Improved Schwarz methods for an elliptic problem in a nonconvex domain with discontinuous coefficients
Authors: Chniti Chokri
Published: May 2008

A matching of singularities in domain decomposition methods with angular domains has been introduced in (Chniti et al., CRAS 342 (2006), 883‐886; Chniti et al., to appear) with the model operator ‐ Δ. This article verifies that the same approach is appropriate for other second order elliptic operators ‐ div(a∇) with a variable coefficient a= a(θ) which is discontinuous with respect to the angular variable θ. © 2008 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2009
The cross‐cultural adaptation of the disability of arm, shoulder and hand (DASH): a systematic review
Authors: Alotaibi Naser M.
Published: May 2008

A systematic review of cross‐cultural adaptations of the Disability of Arm, Shoulder and Hand into other languages was undertaken focusing on the translation and adaptation process, the problems during the translation process and proposed solutions. Nine articles were selected for analysis. All were written in English and addressed the qualitative issues of the cross‐cultural adaptation process. The results demonstrated strong evidence that translation, adaptation and technical issues are most influential in the cross‐cultural adaptation process. Awareness, understanding and incorporation of these issues will assist in future translations and adaptations of occupational therapy evaluation tools for use in other countries with different cultures. Implications for occupational therapy education, practice and research are discussed. Copyright © 2008 John Wiley & Sons, Ltd.
Number of genomic imbalances correlates with the overall survival for adrenocortical cancer in childhood
Authors: Loncarevic Ivan F. , Hering Antje , Posorski Nicole , Linden Tobias , Hoyer Heike , Bucsky Peter
Published: May 2008

Background

Adrenocortical tumours (ACT) in children are rare and, if malignant, often associated with poor prognosis. Relevant cytogenetic factors for prognosis are hardly available.

Procedures

We analysed 14 adrenocortical cancers (ACC) of children by comparative genomic hybridisation (CGH).

Results

The total number of genomic imbalances ranged from 1 to 17 in individual tumour samples. The most common imbalances were +1q (57%), +12p (50%), +12q (50%), +1p (43%), +7q (42%), +9q (42%), +15q (42%), and −4q (57%), −11q (57%), −4p (42%), and −16q (42%). The median number of genomic changes was 5.5 (n = 8) in pT1–pT2 and 15.5 (n = 6) in pT3‐pT4 tumours. The median number was 4 in the eight patients, who remain in remission more than 51 months and 15.5 in the six patients, who have died from the disease within 44 months. Moreover, all seven patients with less than 10 individual imbalances were in remission (median follow‐up 72 months), while all but one patient with 10 and more individual imbalances (n = 7) have died from the disease (median survival time 30 months). Comparison of the data from children and adults revealed characteristic differences. Gain of 1p and loss of 4p, 4q and 16q are frequent in childhood and rare in adults. Inversely, loss of 1p is rare in childhood but frequent in adult ACT.

Conclusion

The number of CGH imbalances appeared to have a predictive value for overall survival in paediatric ACC. Pediatr Blood Cancer 2008;51:356–362. © 2008 Wiley‐Liss, Inc.
Management of retinoblastoma with proximal optic nerve enhancement on MRI at diagnosis
Authors: Armenian Saro H. , Panigrahy Ashok , Murphree A. Linn , Jubran Rima F.
Published: May 2008

Background

In North America, retinoblastoma rarely presents with gross clinical evidence of tumor involving the optic nerve. Extent of microscopic tumor infiltration into the postlaminar optic nerve is a significant risk factor for metastasis, especially if there is tumor at the cut end. Due to poor outcomes in patients with metastatic disease, historical treatment for patients with clinical evidence of extraocular optic nerve involvement has included upfront enucleation followed by aggressive adjuvant chemotherapy. Additional orbital irradiation is advocated for individuals with optic nerve involvement at the surgical margin. Little is known about the role of neoadjuvant therapy in the setting of orbital optic nerve enhancement on magnetic resonance imaging (MRI) at diagnosis.

Methods

A retrospective review of consecutive retinoblastoma cases at Childrens Hospital Los Angeles over a 3‐year period (2004–2006) found to have gadolinium contrast enhancement in the proximal portion of optic nerve on MRI at diagnosis.

Results

Nine patients fit the inclusion criteria. Two had secondary glaucoma of a sufficient degree to cause an enlarged eye (buphthalmos). Median age at presentation was 17 months (2–36 months). All patients received neoadjuvant chemotherapy prior to enucleation. Only two received external beam radiation. All are disease‐free with a median follow‐up of 22 months (12–41 months).

Conclusions

Neoadjuvant chemotherapy is well tolerated prior to enucleation of retinoblastoma‐containing eyes associated with contrast enhancement of the proximal optic nerve on MRI at diagnosis. Such an approach may be used to decrease intensity or duration of chemotherapy and need for external beam radiation. Pediatr Blood Cancer 2008;51:479–484. © 2008 Wiley‐Liss, Inc.
MRI abnormalities of the brain in one‐year‐old children with sickle cell anemia
Authors: Wang Winfred C. , Pavlakis Steven G. , Helton Kathleen J. , McKinstry Robert C. , Casella James F. , Adams Robert J. , Rees Renee C.
Published: May 2008

Background

Sickle cell anemia (SCA) frequently results in damage to the central nervous system (CNS), but the age of onset of these effects is uncertain. We performed MRI examinations of the brain in infants with SCA, who were evaluated as part of the multicenter randomized double‐blinded Pediatric Hydroxyurea Phase III Clinical Trial (BABY HUG).

Methods

Determination of eligibility for enrollment in the trial originally required baseline MRI and magnetic resonance angiography (MRA) of the brain. A standardized imaging protocol was utilized across eight clinical centers. MRI/MRA exams were reviewed by a panel of three neurology/neuroradiology readers and interpretations reported to the coordinating center. Results were correlated with patient age, gender, history, WBC count, platelet count, hemoglobin (Hb), HbF level, score on the Bayley Scales of Infant Development, and velocity on transcranial Doppler ultrasonography (TCD).

Results

Twenty‐three subjects with HbSS were examined at average age 13.7 months (range 10–18 months); 13 were male. Three (13%, CI: 3–34%) had silent infarcts on MRI, two in the right frontal area and one bilaterally. None had MRA abnormalities. The lesions were correlated with increased right‐sided TCD velocity and low HbF level, but not with age, history, Hb level, developmental score, or left‐sided velocity.

Conclusions

Silent brain infarcts occur in a small but significant number of infants with SCA as early as a year of age. This finding indicates a need for thorough evaluation of the CNS very early in life in children with SCA in order to develop timely intervention strategies. Pediatr Blood Cancer 2008;51:643–646. © 2008 Wiley‐Liss, Inc.
A novel type of optically active helical polymers: Synthesis and characterization of poly(N‐propargylureas)
Authors: Deng Jianping , Luo Xiaofeng , Zhao Weiguo , Yang Wantai
Published: May 2008

This article presents two novel artificial helical polymers, substituted polyacetylenes with urea groups in side chains. Poly(4) and poly(5) can be obtained in high yields (≥97%) and with moderate molecular weights (11,000–14,000). Poly(4) contains chiral centers in side chains, and poly(5) is an achiral polymer. Both of the two polymers adopted helical structures under certain conditions. More interestingly, poly(4) exhibited large specific optical rotations, resulting from the predominant one‐handed screw sense. The helical conformation in poly(5) was stable against heat, while poly(4) underwent conformational transition from helix to random coil upon increasing temperature from 0 to 55 °C. Solvents had considerable influence on the stability of the helical conformation in poly(4). The screw sense adopted by the helices was also largely affected by the nature of the solvent. Poly(4‐co‐5)s formed helical conformation and showed large optical rotations, following the Sergeants and Soldiers rule. By comparing the present two polymers (with one NH groups) with the three polymers previously reported (with two NH groups in side chains), the nature of the hydrogen bonds formed between the neighboring urea groups played big roles in the formation of stable helical conformation. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4112–4121, 2008
Synthesis of a new organogelator based on block structures of co‐oligoamide‐6
Authors: Thuillez J. , Thouraud F. , Fleury E.
Published: May 2008

A series of new bisurea derivatives having in common two co‐oligoamide arms have been synthesized and characterized by NMR, SEC, DSC, SEM, and optical microscopy. These compounds are only soluble at high temperature in aprotic polar solvent. By cooling the solutions, gelation occurs if the concentration of these bisurea derivatives is higher than 3% (w/w). Comparisons with derivatives devoid of oligoamide arms leading no gelation suggest that two kinds of interaction are necessary to get the self‐assembling, namely intermolecular hydrogen‐bonding between urea groups and between oligoamide arms. As these interactions induce interconnections in several directions, the possibility of building the long classical fibrous structures is limited. Accordingly, the ultrastructure of the gel consists only of short interconnected fibers. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4122–4129, 2008
Novel temperature‐ and pH‐responsive graft copolymers composed of poly(L‐glutamic acid) and poly(N‐isopropylacrylamide)
Authors: He Chaoliang , Zhao Changwen , Guo Xinhua , Guo Zhaojun , Chen Xuesi , Zhuang Xiuli , Liu Shuying , Jing Xiabin
Published: May 2008

A series of novel temperature‐ and pH‐responsive graft copolymers, poly(L‐glutamic acid)‐g‐poly(N‐isopropylacrylamide), were synthesized by coupling amino‐semitelechelic poly(N‐isopropylacrylamide) with N‐hydroxysuccinimide‐activated poly(L‐glutamic acid). The graft copolymers and their precursors were characterized, by ESI‐FTICR Mass Spectrum, intrinsic viscosity measurements and proton nuclear magnetic resonance (1H NMR). The phase‐transition and aggregation behaviors of the graft copolymers in aqueous solutions were investigated by the turbidity measurements and dynamic laser scattering. The solution behavior of the copolymers showed dependence on both temperature and pH. The cloud point (CP) of the copolymer solution at pH 5.0–7.4 was slightly higher than that of the solution of the PNIPAM homopolymer because of the hydrophilic nature of the poly(glutamic acid) (PGA) backbone. The CP markedly decreased when the pH was lowered from 5 to 4.2, caused by the decrease in hydrophilicity of the PGA backbone. At a temperature above the lower critical solution temperature of the PNIPAM chain, the copolymers formed amphiphilic core‐shell aggregates at pH 4.5–7.4 and the particle size was reduced with decreasing pH. In contrast, larger hydrophobic aggregates were formed at pH 4.2. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4140–4150, 2008
Properties of ZnO(0001) layers grown by metalorganic chemical vapor deposition on GaN(0001) templates
Authors: Ive T. , Ben‐Yaacov T. , Asamizu H. , Van de Walle C. G. , Mishra U. , DenBaars S. P. , Speck J. S.
Published: May 2008

The cover picture of this issue of physica status solidi (c) has been taken from the article [1].
Komplexe Dachformen und ihre Anforderungen an die Unterkonstruktion
Authors: Fick Karlfriedrich , Ramich Alexander , Thiebes Robert
Published: May 2008

In den letzten zwei Dekaden sind die gestalterischen Anforderungen an die Formen von Dächern aus rollgeformten Aluminium‐Profiltafeln stark gestiegen, von einfachen Rechteckformen, über konvex oder konkav gerundete und konisch geschnittene, zu planmäßig ausgebauchten oder eingeschnürten Tafeln für Gebäudehüllen in Ellipsen‐ oder Hyperbelform. Mittels neuer Rollformtechniken können mittlerweile Profiltafeln hergestellt werden, die keine Symmetrie bezüglich ihrer Längsachse mehr aufweisen, sondern, eingeschnürt und ausgebaucht, in der Fläche ihres breiten Gurtes verschwenkt und dazu noch gebogen sein können.

An zwei spektakulären Bauausführen der letzten Jahre wird gezeigt, welch immenser Aufwand in Vorbereitung und Ausführung – von der Tragwerks‐ bis zur Verlegeplanung und von der Unterkonstruktion mit ihrer Vermessung bis zur eigentlichen Dachdeckung – getrieben werden muss, um derart räumlich verformte Profiltafeln zu konstruieren, herzustellen und zu verarbeiten, damit die Anforderungen des Bauherrn und Planers an die sthetik und die Funktion der Aluminium‐Profiltafeln, und die damit gestaltete Gebäudehülle, erfüllt werden können.
Durchknöpftragfähigkeit der Befestigungsmittel von Sandwichelementen bei direkter Befestigung
Authors: Misiek Thomas , Saal Helmut , Kathage Karsten
Published: May 2008

Vergleichende Untersuchungen zu den unterschiedlichen in Europa angewendeten Prüfverfahren zur Ermittlung der Durchknöpftragfähigkeit der Verbindungen von Sandwichelementen ließen ein Sicherheitsdefizit bei den in Deutschland üblichen Versuchen mit Bügelproben vermuten. Im Rahmen eines durch das Deutsche Institut für Bautechnik geförderten Forschungsprojektes konnte diese Vermutung zumindest teilweise entkräftet werden.
The Hybrid SPECT/CT as an Additional Lymphatic Mapping Tool in Patients with Breast Cancer
Authors: van der Ploeg Iris M. C. , Valdés Olmos Renato A. , Kroon Bin B. R. , Nieweg Omgo E.
Published: May 2008

Background

Conventional lymphoscintigraphy does not always define the exact anatomic location of a sentinel node. The lymphatic drainage pattern may be unusual or may not be shown at all. The recently introduced hybrid SPECT/CT imaging could help overcome these difficulties. SPECT is a tomographic version of conventional lymphoscintigraphy and the images have better contrast and resolution. When fused with the anatomical details provided by CT into one image, a meaningful surgical “roadmap” can be created. So far, there is little literature on the use of hybrid SPECT/CT in lymphatic mapping in patients with breast cancer. The purpose of this review was to report on these publications, including our own experience, focusing on patient selection, SPECT/CT settings, anatomic localization, and the detection of additional sentinel nodes.

Methods

The majority of investigators did not formulate indications for additional SPECT/CT after conventional imaging but scanned all patients eligible for sentinel node biopsy. The SPECT/CT settings used in the studies of this review were mostly similar, but the methods used for conventional imaging were more variable.

Results

All studies demonstrated an improved anatomical localization by performing additional SPECT/CT; sentinel nodes outside the axilla or nodes close to the injection site were especially easier to identify. Sentinel nodes were visualized in 89–100% by combined conventional imaging and SPECT/CT, with sentinel nodes depicted only by SPECT/CT in up to 14%.

Conclusion

It is concluded that SPECT/CT shows the exact anatomical location of sentinel nodes, detects sentinel nodes not depicted by conventional imaging, and therefore facilitates surgical exploration. The hybrid SPECT/CT has the potential to make image fusion a routine clinical tool that improves lymphatic mapping in patients with breast cancer.
A treatment protocol for abdomino-pelvic injuries
Authors: Nicodemo Alberto , Decaroli Daniela , Pallavicini Jacopo , Sivieri Roberto , Aprato Alessandro , Massè Alessandro
Published: May 2008

Background

Abdomino-pelvic injuries often present a challenge for the emergency department. Although literature reports several protocols on the treatment of abdomino-pelvic injuries aiming at defining the most advisable treatment line, optimal treatment is still controversial. This paper describes a protocol that has been used to treat abdomino-pelvic injuries in our hospital since 2002.

Materials and methods

In literature different protocol of abdomino-pelvic injuries are described and comparing them most of the difference are the timing of CT scan, the angiography and the laparotomy when treating a lesion of pelvic ring. If patient is haemodynamically instable and presents a lesion of pelvic ring our protocol suggest the simplest and fastest stabilization (pelvic external fixator) in emergency room and delay exam such as CT scan as second level exam. In the presence of an abdominal injury, with a positive focused assessment with sonography for trauma test, the first step should be a pelvic ring stabilization, as laparotomy decreases the abdominal pressure and reduces the tamponade effect on the retroperitoneum. According to presented protocol the angiography is not be a first choice treatment. This protocol was applied to 58 cases of abdomino-pevic injury with unstable pelvic lesions from October 2002 to December 2005. Mean injury severity score was 27.2 (CI  24.1–30.3).

Results

Five patients (8%) died, three due to haemorrhagic shock and two due to pulmonary embolization. Four patients (6.9%) had a partial or complete cauda equina syndrome, four patients (6.9%) complained of mild incontinence, whilst 1 (1.7%) complained of urinary retention with multiple cystitis. Two patients (3.4%) with retention and multiple cystitis, had a malunion and a painful non-union of the fracture. Seven patients (12.3%) had neurological impairment: 5 (8.6%) sciatic nerve palsy, 1 (1.7%) lumbosacral root lesions in a C2-type fracture and there was one case (1.7%) of inconstant lumbago with sciatic pain. Twelve patients reported different levels of sexual dysfunction (20.7%).

Conclusions

Although validation with a larger cohort is required, our preliminary clinical data are similar to, or better than, those reported in the most recent publications on this question, suggesting that this protocol could well reduce both the mortality rate and the long term complications of abdominopelvic injuries.
Internal device decreases antibiotic's efficacy on experimental osteomyelitis
Authors: Hamel Antoine , Caillon Jocelyne , Jacqueline Cédric , Rogez Jean-Michel , Potel Gilles
Published: May 2008

Purpose

We have evaluated the effect of internal and external osteosynthesis devices on the efficacy of vancomycin treatment in a rabbit model of methicillin-resistant Staphylococcus aureus (MRSA)-induced post-traumatic osteomyelitis.

Methods

Double tibial osteotomies in female New Zealand rabbits were performed, inoculated with a MRSA strain, then fixed with an intramedullary rod. A debridement was performed 4 days later for each rabbit, and a bacterial count in pus was determined (B1). In the first group (G1), the osteosynthesis material was removed and replaced by a new sterile nail. In the second group (G2), the intramedullary rod was removed and then replaced by an external fixator. Immediately after surgery, G1 and G2 rabbits were treated with vancomycin (60 mg/kg twice a day). The animals were sacrificed at the end of a 5-day period, and a bacterial count in pus was performed again (B2).

Results

The difference of log10 colony forming units per milliliter (CFU/ml) (B2−B1) was −1.2 ± 0.5 and −2.9 ± 1.1, respectively, for G1 and G2.

Conclusion

The efficacy of vancomycin treatment increased after removal of the internal osteosynthesis device.
The mammalian CHORD‐containing protein melusin is a stress response protein interacting with Hsp90 and Sgt1
Authors: Sbroggiò Mauro , Ferretti Roberta , Percivalle Elena , Gutkowska Malgorzata , Zylicz Alicja , Michowski Wojciech , Kuznicki Jacek , Accornero Federica , Pacchioni Beniamina , Lanfranchi Gerolamo , Hamm Jorg , Turco Emilia , Silengo Lorenzo , Tarone Guido , Brancaccio Mara
Published: May 2008

MINT‐6538515:melusin (Q9R000)physically interacts (MI:0218) with Hsp90 (P07901) by anti bait co-immunoprecipitation (MI:0006)

MINT‐6538566, MINT‐6538556:Hsp90 (P07901) physically interacts (MI:0218) with melusin (Q9R000) by cross-linking studies (MI:0030)

MINT‐6538524:melusin (Q9R000) physically interacts (MI:0218) with Sgt1 (Q9CS74) by anti tag co-immunoprecipitation (MI:0007)

MINT‐6538595:Hsp90 (P07901) physically interacts (MI:0218) with melusin (Q9R000) by enzyme linked immunosorbent assay (MI:0411)

MINT‐6538543:melusin (Q9R000) physically interacts (MI:0218) with Sgt1 (Q9CS74) by anti bait co-immunoprecipitation (MI:0006)

MINT‐6538580: melusin (Q9R000) physically interacts (MI:0218) with Hsp90 (P07901) by surface plasmon resonance (MI:0107)
The nuclear envelope as an integrator of nuclear and cytoplasmic architecture
Authors: Crisp Melissa , Burke Brian
Published: May 2008

Initially perceived as little more than a container for the genome, our view of the nuclear envelope (NE) and its role in defining global nuclear architecture has evolved significantly in recent years. The recognition that certain human diseases arise from defects in NE components has provided new insight into its structural and regulatory functions. In particular, NE defects associated with striated muscle disease have been shown to cause structural perturbations not just of the nucleus itself but also of the cytoplasm. It is now becoming increasingly apparent that these two compartments display co‐dependent mechanical properties. The identification of cytoskeletal binding complexes that localize to the NE now reveals a molecular framework that can seamlessly integrate nuclear and cytoplasmic architecture.
p3 peptide, a truncated form of Aβ devoid of synaptotoxic effect, does not assemble into soluble oligomers
Authors: Dulin Fabienne , Léveillé Frédéric , Ortega Javier Becerril , Mornon Jean-Paul , Buisson Alain , Callebaut Isabelle , Colloc'h Nathalie
Published: May 2008

In previously proposed models of Aβ soluble oligomers, the N‐terminal domain Aβ1–16, which is missing in p3 peptides, protects the hydrophobic core of the oligomers from the solvent. Without this N‐terminal part, oligomers of p3 peptides would likely expose hydrophobic residues to water and would consequently be less stable. We thus suggest, based on theoretical and experimental results, that p3 peptides would have a low propensity to assemble into stable oligomers, evolving then directly to fibrillar aggregates. These properties may explain why p3 would be devoid of any impact on synaptic function and moreover, strengthen the hypothesis that Aβ oligomers are the principal synaptotoxic forms of Aβ peptides in Alzheimer disease.
Loss of Parliamentary Control Due to Mediatization and Europeanization: A Longitudinal and Cross-Sectional Analysis of Agenda Building in the United Kingdom and the Netherlands
Authors: VAN NOIJE LONNEKE , KLEINNIJENHUIS JAN , OEGEMA DIRK
Published: May 2008

The central question in this study is whether the power of the media agenda over the political agenda has recently increased. The agenda-building dynamics are established using cross-country time-series data on four issues, covering fifteen and eight years respectively of British and Dutch parliamentary debates and newspaper articles. Structural equation models show that the parliamentary agenda is more influenced by the media agenda than the other way around, and that the power balance has shifted even more in favour of the media. It is additionally found that media power is especially associated with issues within the European domain. This study contributes empirically to the 'mediatization' debate in a EU context, which is largely limited to the realm of theoretical speculation.
Policy Dissension and Party Discipline: The July 2005 Vote on Postal Privatization in Japan
Authors: NEMOTO KUNIAKI , KRAUSS ELLIS , PEKKANEN ROBERT
Published: May 2008

This article examines party discipline and party cohesion or defection, offering as an illustration the rebellion over postal privatization in 2005 by members of Japan's Liberal Democratic Party (LDP). It explores the importance of party rules – especially the seniority rule and policy specialization for district rewards – as intervening variables between election rules and party defection in a decentralized and diverse party. It is argued that in such cases, party rules like seniority can help prevent defection. When these rules are changed, as in the postal case of 2005, defection is more probable, but it is found that the relationship between defection and seniority is likely to be curvilinear, and also that the curvilinearity is conditional upon each legislator's having different incentives for vote, policy and office.
The Autoregressive Influence of Social Network Political Knowledge on Voting Behaviour
Authors: RICHEY SEAN
Published: May 2008

Social networking has a powerful influence on voters, but we do not know enough about the mechanisms of network influence. Recent research shows that one network member's influence is highly dependent on the others in the network, i.e. autoregressive. I test whether the influence of social network political knowledge is also autoregressive. I show that a strong predictor of vote choice similarity is the level of knowledge of the discussant, but greater knowledge of the other network members lessens dyadic agreement. Data from the American National Election Study collected in 2000 show that in the presidential election of 2000 having a knowledgeable discussant increases the chance of vote similarity with that discussant by 5 percentage points, but vote similarity decreases by 10 percentage points for each level of residual network knowledge. This research confirms the autoregressive influence of social network political knowledge.
The utilization of large savanna trees by elephant in southern Kruger National Park
Authors: Shannon Graeme , Druce Dave J. , Page Bruce R. , Eckhardt Holger C. , Grant Rina , Slotow Rob
Published: May 2008

Elephant are believed to be one of the main ecological drivers in the conversion of savanna woodlands to grassland. We assessed the impacts of elephant on large trees (≥5 m in height) in the southern section of the Kruger National Park. Tree dimensions and utilization by elephant were recorded for 3082 individual trees across 22 transects (average length of 3 km and 10 m wide). Sixty per cent of the trees exhibited elephant utilization and 4% were dead as a direct result of elephant foraging behaviour. Each height class of tree was utilized in proportion to abundance. However, the size of the tree and the species influenced the intensity of utilization and foraging approach. Sclerocarya birrea was actively selected for and experienced the highest proportional utilization (75% of all trees). Interestingly, the proportion of large trees that were utilized and pushed over increased with distance from permanent water, a result which has implications for the provision of water in the KNP. We conclude that mortality is likely to be driven by a combination of factors including fire, drought and disease, rather than the actions of elephant alone. Further investigation is also required regarding the role of senescence and episodic mortality.
Effects of habitat disturbance on ant community composition and seed dispersal by ants in a tropical dry forest in Costa Rica
Authors: Zelikova Tamara J. , Breed Michael D.
Published: May 2008

Habitat alteration can have far-reaching consequences for natural communities and can alter existing species interactions in profound ways. Working in a tropical dry forest ecosystem in the Guanacaste Province of Costa Rica, we measured seed removals and seed dispersal distances forAcacia collinsiiand papaya seeds to determine if habitat disturbance affects ant community composition and the associated interactions between ants and seeds. Two hundred and forty experimental seed depots were observed in four sites that differed in land-use history and disturbance severity: secondary forest, forest edge,Acacia collinsiiedge, and open-pasture. Both seed removals and average dispersal distances achieved by ants differed among habitats. Habitat disturbance did not negatively affect seed removals by ants in our study; seed removals were highest in the most disturbed habitat, the open pasture (38.3% of seeds removed within 2 h). Ant community composition and the relative abundance of key seed dispersers also differed among habitats. In all sites combined, ten species of ant were observed dispersing seeds, with two species,Pheidole fallaxandEctatomma ruidum, in combination being responsible for 92% of all observed seed removals. The abundance ofP. fallaxandE. ruidumdiffered among habitats, withE. ruidumbeing the most abundant ant species collected in the open-pasture habitat andP. fallaxbeing the most abundant in the edge habitats.Pheidole fallaxants dispersed seeds significantly further (mean ± SD = 2.11 ± 1.35 m, maximum = 5.2 m) than didE. ruidum(mean ± SD = 0.7 ± 0.81 m, maximum = 3.85 m), a difference we attribute to recruitment behaviour and not body size. Habitat disturbance thus alters the ant community and the relative abundance of key seed-dispersing ant species, with cascading effects on seed removals and seed dispersal distances.
The role of the olive baboon (Papio anubis, Cercopithecidae) as seed disperser in a savanna-forest mosaic of West Africa
Authors: Kunz Britta Kerstin , Linsenmair Karl Eduard
Published: May 2008

Primates are among the major groups of frugivores in the tropics, but little is known about their role in natural regeneration of African savanna ecosystems. In the savanna-forest mosaic of north-eastern Ivory Coast the olive baboon (Papio anubis Lesson) harvests fruit from at least 79 plant species. Over a 24-mo study period, 396 faecal samples from 10 groups of baboons were analysed in terms of quantitative and qualitative aspects of seed handling and dispersal (excluding grasses and sedges). Seventy-three per cent of seeds in faecal samples were undamaged. Intact seeds were from 65 species. On average, defecations contained intact seeds from 2.0 species (range = 0–10). Seed size varied between 1 and 27 mm, and 77% of the species had medium-sized to large seeds. No linear correlation between mean seed size and seed damage was found. Eighteen out of 19 species tested were viable after ingestion, but effects of gut passage upon germination varied widely. The baboon population in the study area (145 km2) dispersed an estimated 1483 intact seeds d−1km−2(129 seeds > 2 mm in size). The results suggest that the olive baboon is an important seed disperser in the savanna-forest ecosystem of West Africa.
Host generalists dominate fungal communities associated with seeds of four neotropical pioneer species
Authors: Kluger Courtney G. , Dalling James W. , Gallery Rachel E. , Sanchez Evelyn , Weeks-Galindo Cheyenne , Arnold A. Elizabeth
Published: May 2008

Most ecological studies of fungi associated with tropical plants have focused on the rhizosphere or phyllosphere of seedlings, saplings and adult trees (Augspurger 1983, 1984; Bell et al. 2006, Gilbert 2002, Gilbert et al. 2002, Husband et al. 2002, Kiers et al. 2000, Mangan et al. 2004). However, fungi also infect the seeds of tropical trees, reducing seed survival and potentially affecting adult distributions (Gallery et al. 2007a, b). Fungicide experiments have shown that fungal and oomyceteous pathogens are the major cause of seed mortality in the soil for a variety of tropical pioneers (Dalling et al. 1998, Gallery et al. 2007b, Murray & Garcia 2002), which depend on recruitment from seed banks to colonize gaps and other disturbances in mature forest (Alvarez-Buylla & Martinez-Ramos 1990, Dalling et al. 1997, Hall & Swaine 1980). Persistence in the soil prolongs exposure of seeds to infection by soil-borne fungi and is especially problematic for small-seeded species with thin fruit or seed walls (Baskin & Baskin 1998, Blaney & Kotanen 2002, Crist & Friese 1993). At present little is known about the host affinity of fungi associated with seeds of tropical trees, and consequently, whether seed-infecting fungi influence plant species coexistence through differential infection of, or effects on, potential hosts.
Interactions between galling insects and leaf-feeding insects: the role of plant phenolic compounds and their possible interference with herbivores
Authors: Pascual-Alvarado Enrique , Cuevas-Reyes Pablo , Quesada Mauricio , Oyama Ken
Published: May 2008

The objective of this study was to determine the effects of gall induction on leaf phenolic compounds and their indirect effects on the subsequent attack of folivorous insects inAchatocarpus gracilis,Cordia alliodora,Guapira macrocarpa,Guettarda ellipticaandRuprechtia fuscathat occur in both hillside and riparian sites at Chamela-Cuixmala tropical dry forest in western Mexico. There are differences in soil water content between riparian and hillside sites where trees in the first are mainly evergreen and deciduous in the second. A few tree species occur in both sites and their intraspecific phenological response is also different between sites. In this case, trees of a given species that occur in riparian sites will be evergreen whereas trees on hillsides of the same species will be deciduous. Four plant species had significantly greater total phenol concentrations in galled than ungalled leaves in both deciduous hillside and riparian sites. In three plant species associated with galls, host total phenol concentrations were significantly greater in short than in tall plants. The frequency and amount of folivore damage were greater in leaves without galls than leaves with galls in these four plant species. These results indicate that galling insect species may directly affect leaf phenolic concentrations and indirectly may affect the incidence and consumption of folivorous insects in tropical plant species. This may have important consequences on the preference of leaves by folivorous insects that might be excluded by galling insect species in this dry tropical system.
The Role of Gender in Teachers’ Perceived Stress and Heart Rate
Authors: Serrano Miguel Angel , Moya-Albiol Luís , Salvador Alicia
Published: May 2008

Gender differences in cardiovascular variables in response to laboratory stressors have been described. In real situations, although occupational stress is considered one of the major causes of cardiovascular diseases, there are few studies that follow a psychophysiological approach, such as in a work context. In these settings, excessive environmental demands might produce nonadaptive emotional responses, depending on the way people perceive their work settings. Concretely, there are few published studies that take into account the changes of perceived stress (PS) and/or heart rate (HR) considering the ecological moment. Thus, our interest was to study the changes of both variables during two working days (WDs). Moreover, we considered the effect of gender as a modulator of these variables. For this purpose, 35 full-time school teachers participated in the research. PS was measured by means of a self-report and HR was continuously recorded during the WD at the beginning and end of an academic year. Results showed changes in HR during the WD and higher PS levels when teachers were with students on both WDs. Furthermore, there were increases in both variables at the end of the academic year. In spite of the similar responses in both variables studied, HR and PS did not correlate significantly. We conclude that our data, taken from a real work setting, show that HR and PS responses to a WD in teachers seems to be different, showing some gender differences.
Antecedents and the Performance Outcome of Transactive Memory in Daycare Work Groups
Authors: Peltokorpi Vesa , Manka Marja-Liisa
Published: May 2008

Laboratory experiments provide evidence that ongoing social interactions support the formation, functioning, and maintenance of transactive memory (TM), which in turn has positive performance implications in dyads and groups. Because most studies have been conducted with students, relatively little is known about TM in work settings. This study examined the mediating role of TM between interpersonal communication, group potency, supportive supervision, and self-reported group performance in 33 daycare work groups. Hierarchical regression analysis showed that TM fully mediated the interpersonal communication and group performance linkage, and partially mediated the group potency and group performance linkage. Implications and suggestions for future research are offered.
Fluency and Cognitive Effort During First- and Second-Language Notetaking and Writing by Undergraduate Students
Authors: Piolat Annie , Barbier Marie-Laure , Roussey Jean-Yves
Published: May 2008

This study concerns the cognitive effort expended and the difficulties experienced by undergraduate students as they took notes and wrote a text based on a lecture given in French, their primary language (L1), and in English (L2). The 21 participants had studied English (L2) for 7 years before attending the university and they had taken 3 years of intensive courses at the university in order to obtain their first diploma in English (“license”). Participants were first trained on a secondary task that allowed us to measure their cognitive effort while they performed two other main tasks in both languages, namely (1) listening and taking notes on the main ideas of the lecture, and (2) writing a text based on their notes. Participants also answered a questionnaire about their difficulties with comprehension, taking notes, making use of their notes, and writing in both languages. The results indicated that writing processes were more effortful than notetaking. Students’ performance on the writing task did not vary across languages. In contrast, the cognitive effort associated with taking notes was greater for L2 than for L1, and writing speed was slower. More difficulty was also experienced for notetaking, especially in L2, than in writing.
Family Traditionalism and Family Structure
Authors: van der Valk Inge , Spruijt Ed , de Goede Martijn , Larsen Helle , Meeus Wim
Published: May 2008

The present study examined how tolerance toward nontraditional family forms relates to family structure, by examining differences between youngsters and parents from intact and postdivorce families. We also explored whether intergenerational transmission of attitudes toward nontraditional family forms differed between intact and postdivorce families. We made use of three-wave longitudinal data of 959 adolescents and young adults aged 12 years to 24 years at the first wave, and also of one of the parents. Longitudinal multilevel analyses revealed that both youngsters and parents of postdivorce families are more tolerant toward nontraditional family forms and that parental attitude transmission is significantly lower in families after a divorce. Results apply to respondents of a broad age range. Several explanations are suggested for the flawed intergenerational transmission of attitudes in postdivorce families.
Core Self-Evaluations
Authors: Brunborg Geir Scott
Published: May 2008

Core self-evaluations (CSE), a personality construct underlying self-esteem, locus of control, generalized self-efficacy, and neuroticism, has previously been found to relate strongly to job satisfaction. While previous research has shown relationships between personality traits and various adverse psychosocial job outcomes, no published studies have looked at the relationship between CSE and job stress. A study was conducted to test the effects of job demands, job control, and social support, as hypothesized in the job demand control support (JDCS) model, and the effect of CSE on job stress. Two hundred and twelve employees from 12 work places in southern Norway filled in a questionnaire consisting measures of job demands, job control, social support, CSE, and job stress. Initially, the results from hierarchical multiple regression analysis showed significant main effects of demands and control on job stress. However, when social support was included in the analysis, control was no longer significant. In addition, ANOVA showed that the two-way job demands × job control interaction effect, and the three way job demands × job control × social support interaction effect, as predicted by the JDCS model, were nonsignificant. The results showed a strong positive main effect of CSE on perceived job stress, and that CSE accounted for a large proportion of the variance in job stress. This is in accordance with studies that have shown relationships between other personality measures and job stress. The present study confirms the relevance of CSE for further research on links between personality and job stress.
Center-Surround or Spreading Inhibition
Authors: Frings Christian , Bermeitinger Christina , Wentura Dirk
Published: May 2008

In the paradigm of repeated masked semantic priming ( Wentura & Frings, 2005 ), prime and mask are repeatedly and rapidly interchanged. Using this technique in a semantic priming task with category labels as primes and category exemplars as targets (related, e.g., BIRD – swan → BIRD – finch; unrelated, e.g., BIRD – lily → FRUIT – finch), Wentura and Frings found a negatively signed priming effect. Here we used the repeated masking technique with category exemplars as targets and primes (i.e., identity priming) for analyzing, whether this effect reflects center-surround or spreading inhibition. If the repeated masked technique reflects spreading inhibition, a negative effect should also appear for identity priming. In contrast, a center-surround approach would predict a positive effect. In accordance with the latter hypothesis, we found a significant positive effect in identity priming (Experiment 1a) and significant difference to the negatively signed semantic priming effect when primes were category labels (Experiment 1b). This is indicative of the repeated masked semantic priming effect being a negatively signed semantic priming effect due to a center-surround mechanism.
Investigating the Effect of Mental Set on Insight Problem Solving
Authors: Öllinger Michael , Jones Gary , Knoblich Günther
Published: May 2008

Mental set is the tendency to solve certain problems in a fixed way based on previous solutions to similar problems. The moment of insight occurs when a problem cannot be solved using solution methods suggested by prior experience and the problem solver suddenly realizes that the solution requires different solution methods. Mental set and insight have often been linked together and yet no attempt thus far has systematically examined the interplay between the two. Three experiments are presented that examine the extent to which sets of noninsight and insight problems affect the subsequent solutions of insight test problems. The results indicate a subtle interplay between mental set and insight: when the set involves noninsight problems, no mental set effects are shown for the insight test problems, yet when the set involves insight problems, both facilitation and inhibition can be seen depending on the type of insight problem presented in the set. A two process model is detailed to explain these findings that combines the representational change mechanism with that of proceduralization.
Characterization of the atmosphere during SEN2FLEX 2005 field campaign
Authors: Estellés Víctor , Molero Francisco , Gómez‐Amo José L. , Fortea Juan C. , Pedrós Roberto , Utrillas María P. , Pujadas Manuel , Guanter Luis , Martínez‐Lozano José A.
Published: May 2008

The European Space Agency carried out the Sentinel‐2 and Fluorescence Experiment (SEN2FLEX) campaign in Barrax (Spain) during the summer of 2005, with the main objective of observe solar induced fluorescence signal using the AirFLEX airborne instrument over different vegetation targets in order to verify signal suitability for observations from space as proposed in the FLEX mission. A highly precise atmospheric correction is mandatory for adequate measurements of the AirFLEX instrument; thus a complete characterization of the atmosphere was programmed in SEN2FLEX in order to document the presence of atmospheric aerosols above the experimental area, as their effects represent the major source of uncertainty in atmospheric correction algorithms. In this work, an analysis of the atmospheric data is presented focusing on its eventual application to atmospheric correction of satellite imagery. Validation of Compact Airborne Spectrographic Imager (CASI) aerosol optical depth and columnar water vapor content retrievals has been included as an example of application to remote sensing products. A relevant feature was the arrival of a Saharan dust intrusion from 13 to 15 July, yielding the increase of aerosol optical depth at 550 nm from 0.1 to 0.5 because of changes in the vertical distribution of aerosols, with a transport layer located between 1.5 and 4 km. An accurate knowledge of these aerosol features will be relevant in future implementation of atmospheric correction code of the airborne and satellite hyperspectral imagery.
Electrically small supergain end‐fire arrays
Authors: Yaghjian A. D. , O'Donnell T. H. , Altshuler E. E. , Best S. R.
Published: May 2008

The theory, computer simulations, and experimental measurements are presented for electrically small, two‐element supergain arrays with near‐optimal end‐fire gains of 7 dB. We show how the difficulties of narrow tolerances, large mismatches, low radiation efficiencies, and reduced scattering of electrically small parasitic elements are overcome by using electrically small resonant antennas as the elements in both separately driven and singly driven (parasitic), two‐element, electrically small supergain end‐fire arrays. Although rapidly increasing narrow tolerances prevent the practical realization of the maximum theoretically possible end‐fire gain of electrically small arrays with many elements, the theory and preliminary numerical simulations indicate that near‐maximum supergains are also achievable in practice for electrically small arrays with three (and possibly more) resonant elements if the decreasing bandwidth with increasing number of elements can be tolerated.