bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Human Disturbance on Colony Productivity of the Social Wasp Polistes versicolor Olivier (Hymenoptera: Vespidae)
Authors: Torres Romario Ferreira , Torres Viviana de Oliveira , Súarez Yzel Rondon , Antonialli-Junior William Fernando
Published: June 2014

Currently, the main impacts on biodiversity are generated by human activities in natural environments. Monitoring the number of species of social wasps nesting attached to buildings is important to evaluate the effect of this activity on colony productivity. This study evaluated the effect of human activity on the productivity of colonies of the wasp Polistes versicolor. We evaluated 20 abandoned nests and compared the productivity parameters: number of cells constructed, number of adults produced, nest dry mass, proportion of productive cells, number of generations, height of central and peripheral cells, and diameter of the petiole. Most of these parameters showed higher values in the colonies nesting in the area of low human activity. Therefore, productivity was significantly higher in the area with low human activity. In the nests, regardless of the site, the cells that were central and closer to the petiole were the most productive. Colonies in the two areas used different strategies: in the area of intense human activity, the wasps invested more in reusing cells than in enlarging the nest. However, the species continues to nest in the urban area, probably because of decreased interspecific competition, predation, and interference from climate variations.
Congregation Sites and Sleeping Roost of Male Stingless Bees (Hymenoptera: Apidae: Meliponini)
Authors: Santos Charles Fernando dos , Menezes Cristiano , Vollet-Neto Ayrton , Imperatriz-Fonseca Vera Lucia
Published: June 2014

Very little is known about stingless bee reproductive biology or male behaviour. In this note we provide the first observations on the male aggregations (congregation sites and roosting sites) of some stingless bee species. Our observations show that males of two stingless bee species can congregate on the same site. We also report for the first time the substrates used by stingless bee males for resting at night, that at least one species forms large sleeping roosts composed of hundreds of individuals, and that sleeping roost locations are not reused on subsequent nights.
Political Change in North Africa and the Arab Middle East: Constitutional Reforms and Electoral Processes
Authors: Inmaculada Szmolka
Published: June 2014

The aim of this study is to examine, from a comparative focus, the processes of political change, which have come about as a result of the revolutions and upheavals in North Africa and the Arab Middle East countries since December 2010. Previous experiences have shown that democracies tend to emerge in waves. Nevertheless, our hypothesis is that we cannot generalize by referring to a new wave of democratization in this region, but rather, we need to focus on processes of change of a different political nature (the establishment of democracy, political liberalization, and in some cases, the immobility of authoritarian regimes). In this research, we describe the constitutional and legal reforms, and the elections held to date. Finally, we evaluate the scope of these processes and assess their impact on the nature of political regimes in the Arab world.
Models of pre-service teachers' academic achievement: The influence of cognitive motivational variables
Authors: Castro-Villarreal Felicia , Guerra Norma , Sass Daniel , Hseih Pei-Hsuan
Published: June 2014

Theoretical models were tested using structural equation modeling to evaluate the interrelations among cognitive motivational variables and academic achievement using a sample of 128 predominately Hispanic pre-service teachers enrolled in two undergraduate educational psychology classes. Data were gathered using: (1) a quantitative questionnaire to assess personal control, internal causality, self-efficacy, mastery goal orientation, and final course grade and (2) a problem-solving activity to identify engagement style: action- or process-oriented. The proposed theoretical model produced a poor model fit and thus a modified model was forwarded that directly linked self-efficacy with final course grade rather then mediated by mastery goal orientation. Results supported the modified model and suggested that the cognitive motivational variables under investigation played important roles in predicting students’ grades, with self-efficacy acting as the mediator between both internal causality and personal control and students’ final course grade. This study also demonstrated that the modified model was relatively invariant across gender, ethnicity, and engagement style. Implications for both teacher educators and teachers for understanding the complex links between cognitive motivational variables and academic achievement with a predominately Hispanic sample are discussed.
Assessing Interdisciplinary Learning and Student Activism in a Water Issues Course
Authors: Juris Stephen J. , Mueller Anja , Willermet Cathy , Drake Eron , Upadhaya Samik , Chhetri Pratik
Published: June 2014

In response to a request from a campus student organization, faculty from three fields came together to develop and teach an integrated interdisciplinary course on water issues and social activism. This course, “Water as Life, Death, and Power”, brought together issues from the fields of anthropology, biology and chemistry to explore water rights, access to clean water, and water treatment methods. Students enrolled in the course developed interdisciplinary projects related to a variety of local and global water issues to present real-world solutions at a university-wide student research showcase. This article reports the assessment outcomes of the course, measuring changes in both interdisciplinary learning and levels of student activism.
Group simulation for “authentic” assessment in a maternal-child lecture course
Authors: Hensel Desiree , Stanley Leah
Published: June 2014

The purpose of this pilot study was to explore student perceptions and outcomes surrounding the use of a labor and delivery simulation as a midterm exam in a maternal-newborn lecture course.  An exploratory case study design was used to gain a holistic view of the simulation experience.  Data from focus groups, written debriefings, simulation scoring rubrics, student course evaluations, and other course exams were analyzed using Stake’s case study method.  Qualitative analysis revealed four themes: confidence, fairness, reliability, and team effort.  Students were able to accurately grade the performance of their group as a whole and complete a group self-debriefing, but quantitative analysis showed that the group scores were significantly higher than other individual course grades. The findings suggested that the group simulation was an authentic assessment of teamwork, but not individual performance. Future research is needed to determine what role simulation and collaborative testing should play in pre-licensure education.
Active optics with a minimum number of actuators
Authors: Lemaitre Gerard R.
Published: June 2014

Optics for astronomy implies powerful developments of active and adaptive optics methods applied to instrumentation from X-rays to the near infrared for the design of telescopes, spectrographs, and coronagraph planet finders. This presentation particularly emphasizes the development of active optics methods. Highly accurate and remarkably smooth surfaces from active optics methods allow new optical systems that use highly aspheric and non-axisymmetric – freeform – surfaces. Depending on the goal and performance required for a deformable optical surface, elasticity theory analysis is carried out either with small deformation thin plate theory, large deformation thin plate theory, shallow spherical shell theory, or the weakly conical shell theory. A mirror thickness distribution is then determined as a function of associated bending actuators and boundary conditions. For a given optical shape to generate, one searches for optical solutions with a minimum number of actuators.
The Four-Laser Guide Star Facility: Design considerations and system implementation
Authors: Calia Domenico Bonaccini , Hackenberg Wolfgang , Holzlöhner Ronald , Lewis Steffan , Pfrommer Thomas
Published: June 2014

Ground-based optical telescopes, in particular large ones, require adaptive optics to overcome the atmospheric seeing limit due to turbulence. Correcting the distorted wavefront necessitates bright stars in the field of view. The sky coverage can be greatly increased by using artificial sodium laser guide stars in addition to natural guide stars. We describe the underlying physics and technical considerations relevant to such systems before discussing the design of the four-laser guide star facility (4LGSF) which is currently under development for the ESO Very Large Telescope (VLT) on Cerro Paranal, Chile. The focus is upon the justification of the requirements and their technical solution.
Cournot and Bertrand Competition in a Model of Spatial Price Discrimination with Differentiated Products
Authors: Sun Chia-Hung
Published: June 2014

This study investigates spatial price discrimination with two types of market competition – price competition and quantity competition – and two kinds of cross-relations between goods – substitutes and complements – with endogenous location choices in a barbell model. The results herein present that the maximum differentiation (end point agglomeration) is the unique location equilibrium with substitutes (complements), irrespective of what type of competition. We demonstrate that if the unit transportation rate is sufficiently high, then consumer surplus, profits, and social welfare are higher under price competition than under quantity competition for both substitutes and complements. This means that introducing a spatial barrier to competition generated through transportation costs may solve the problem of inconsistency from the conflict interests between consumers, firms, and a social planner.
Lignin masks the presence of fibrillar network structure in the cell corner middle lamella (CCML)
Authors: Kim Yoon Soo , Lee Kwang Ho , Kim Jong Sik , Singh Adya P.
Published: June 2014

The presence of fibrillar structures (FS) in the cell corner middle lamella (CCML) regions was demonstrated in several species of plants. The FS in the CCML of bass wood, oak wood, and bamboo became clearly visible after removal of lignin by wood decay fungi. The occurrence of FS in the CCML was also confirmed by examining early stages of cell wall formation in silver poplar, Japanese red pine, Arabidopsis and alfalfa. The fibrillar texture became increasingly less defined with the onset of lignification as the interfibrillar spaces were masked by lignin polymers and the fibrillar network became embedded within the lignin matrix. The FS stained positively with PATAg and ruthenium red, which is interpreted to be an indicator of the presence of structural polysaccharides (non-cellulosics and pectins). Our work demonstrated that fibrillar network is a characteristic feature of CCML of plant cell walls that is clearly visible prior to lignification of this cell wall region, but becomes invisible after the deposition of lignin.
Effect of Surface Chemistry and Structure of Sludge Particles on Their Co-slurrying Ability with Petroleum Coke
Authors: Liu Meng , Duan Yufeng , Ma Xiuyuan
Published: June 2014

Gasification and combustion performance of petroleum coke–water slurry (PCWS) can be enhanced by the addition of sludge. In this study, we have mixed three types of sludge with petroleum coke to form petroleum coke–sludge slurry (PCSS) and analyzed the effects of surface chemistry and structure of the sludge samples on the rheological properties of PCSS. Results show that the surface of petroleum coke particles is strongly hydrophobic, while the surface of sludge particles is hydrophilic. The sludge particles primarily consist of oxide and mineral salts, while petroleum coke particles mainly consist of organic carbon. Modification of the sludge changes the distribution of mineral components on the surface of sludge. In addition, the surface area, pore structure, and size of sludge tend to increase after modification. Sludge shows strong shear-thinning behavior, while the rheological properties of PCWS change from shear-thickening to shear-thinning behavior with excessive addition of sludge more than 6 wt.%. The suitable mass concentration for industrial application of PCSS is determined to be 62–64 wt.% for the sludge addition of 10–15 wt.%. Increasing the amount of sludge may enhance the yield stress and improve the static stability of PCSS, and sludge might be the most effective stabilizer used in PCWS.
Impact of maternal body mass index on the cesarean delivery rate in Germany from 1990 to 2012
Authors: Kyvernitakis Ioannis , Köhler Christine , Schmidt Stephan , Misselwitz Björn , Großmann Jasmin , Hadji Peyman , Kalder Matthias
Published: June 2014

Aims: Maternal obesity is a risk factor for cesarean delivery (CD). The aim of this analysis was to determine the association between early-pregnancy body mass index (BMI) and the rate of CD over the past two decades.

Methods: We retrospectively analyzed data from the perinatal quality registry of singleton deliveries in the state of Hesse in Germany from 1990 to 2012. We divided the patients into groups according to the WHO criteria for BMI: underweight (<18.5), normal weight (18.5–<25), overweight (25–<30), obese class I (30–<35), obese class II (35–<40), and obese class III (≥40).

Results: The analysis included 1,092,311 patients with available data regarding maternal BMI and mode of delivery. The CD rates for underweight (<18.5), normal weight (18.5–<25), overweight (25–<30), obese class I (30–<35), obese class II (35–<40), and obese class III (≥40) women increased from 14.4%, 16.1%, 19.5%, 22.3%, 25%, and 26.9% in the year 1990 to 27.9%, 31.4%, 38.8%, 45.1%, 50.2%, and 55.2% in the year 2012, respectively (P<0.001).

Conclusion: Maternal BMI in early pregnancy is linearly associated with the incidence of CD. We found a disproportionate increase of CD in morbidly obese women compared with the CD incidence in the reference BMI population over the past two decades.
Neither Neo- nor Post-
Authors: Benjamins Rick
Published: June 2014

A liberal theology that values the individual, the person or the subject, is required to defend itself for its ally with individualism and human-centered philosophies, since the concept of the individual or the person has become problematic, as it is radicalized in neoliberalism and sharply criticized by postmodernism. After the First World War Ernst Troeltsch distinguished a German from a Western perspective at the basis of a liberal view of humanity, which he wanted to synthesize in order to secure human dignity and advance the acceptance of universal human rights. Even though our situation has changed profoundly, Troeltsch’s distinction is still very helpful, since both neoliberalism and postmodernism can be described as one-sided radicalizations of what he labeled as ‘German’ and ‘Western’ ways of thought. Analysis shows that both neoliberalism and postmodernism fail to formulate the commonalities of a common human nature due to their radicalization. In contrast to neoliberalism and postmodernism, a liberal theology is challenged to value the individual within the bond of a common human nature and to describe this nature without the restrictions or prescriptions of an essentialist definition of what is human. The concept of a common humanity without essentials is defended with reference to Foucault and Hegel and supported by the classical notion of the image of God.
Leid: Durch das Dunkel zum Heil?
Authors: Gasser Georg
Published: June 2014

Eleonore Stumps langjährige Beschäftigung mit dem Theodizee-Problem kulminiert in ihrem
Kinetic degradation and storage stability of β-carotene encapsulated by spray drying using almond gum and gum arabic as wall materials
Authors: Mahfoudhi Nesrine , Hamdi Salem
Published: June 2014

The aim of this study was to evaluate the ability of almond gum, as a novel polymer, to encapsulate β-carotene by spray drying, in comparison with gum arabic. Encapsulation efficiency (EE) was around 66% and 70% using almond gum and gum arabic, respectively, and the reconstituted emulsions had relatively higher particle sizes than the fresh emulsions. A 60-day storage period at 25°C was carried out to investigate the effect of relative humidity (RH) on the kinetic degradation and on the decrease of the color of β-carotene powders. Results showed that β-carotene and color degradations were found to fit well with a first-order kinetic model. Degradation rates increased as RH increased, until a value at which the samples become sticky and collapsed (80% RH) when the degradation rate decreased. These results could prove that collapse phenomena were responsible for the decrease of the degradation rate by decreasing the diffusion of oxygen throughout the wall materials.
Design of Iosipescu Shear Test for Applying to a Bi-Modulus Ceramic-Fiber-Reinforced SiO2 Aerogel
Authors: Sun Yantao , Shi Duoqi , Yang Xiaoguang
Published: June 2014

Tension and compression tests were conducted on a ceramic-fiber-reinforced SiO2 aerogel (CFRSA). The material exhibits different tension and compression modulus, i.e., bi-modulus. The objective of present research is to establish guidelines for preparing shear tests of this CFRSA. Finite-element analysis (FEA) on various Iosipescu specimens is presented for four bi-modulus materials, including the CFRSA. It is found that the major concerns for specimen design of bi-modulus materials are: the uniformity of shear stress and the longitudinal normal stress concentration at notch tips. These concerns are all dependent on material properties. For material with Et numerically close to Ec, the normal stress concentration near notch tips is of less significance. However, for material with high tension–compression asymmetry, including this CFRSA, the normal stress concentration near notch tips is significant. The round-notch specimen with small normal stress concentration seems to be favorable for these materials.
Threshold Values of Performance Indicators for Asphalt Concrete Pavement to Apply to Pavement Performance Warranty
Authors: An DeokSoon , Nam JeongHee , Kwon SooAhn , Suh YoungChan , Lee JaeJun
Published: June 2014

The performance warranty system is quite innovative in requiring a contractor’s warranty for pavement performance over a certain period of time. European countries adopted performance warranty systems about 40 years ago. The United States adopted this system in the early 1990s to improve construction quality and performance, as well as to reduce life cycle cost. In Korea, for the purpose of resolving construction management and quality control problems and poor construction, the performance warranty system is considered as part of the solution. The appropriate performance indicators, reasonable threshold values, and warranty periods have to be selected in order to adopt a performance warranty system that requires keeping the pavement performance above a certain level of satisfaction for the warranty period. For this reason, structural, functional, and safety performance were defined first, and then rut depth, roughness, and crack ratio were selected as performance warranty indicators. For the purpose of suggesting performance warranty threshold values that reflect domestic circumstances, pavement management system data were surveyed, a special project was conducted, and a total of 888 sample sections were analyzed. A threshold level at 95 % of each indicator’s distress was determined for the threshold value; this prevents the worst 5 % of poor performance cases. A 14-mm rut depth, 3.6 m/km International Roughness Index, and 20 % crack ratio for five years were selected as threshold values. To avoid early deterioration of pavement, three- to five-year warranty periods are suggested.
Determination of Heat Transfer Coefficients in High Speed Quenching Processes
Authors: Frerichs F. , Sander S. , Lübben T. , Schüttenberg S. , Fritsching U.
Published: June 2014

Rapid water quenching of steel specimen in heat treatment processes can evoke compressive residual stresses near the specimen surface. Thereby a significant increase in the fatigue limit of the components may be achieved. For applying this process, knowledge and control of heat transfer coefficients (HTC) in various process conditions during quenching is necessary. For HTC lower than 10 kW/m2K, temperature measurements with thermocouples below the surface of steel components may be performed. However, for measurements of HTC above 10 kW/m2K, the local cooling rates are huge near to and at the surface and the resulting temperature gradients are high. For these rapid temperature changes, the response times of sheathed thermocouples are not sufficient and because of the high temperature gradients also the positioning of the thermocouples within the specimen must be very accurate. The most appropriate possibility to determine HTC above 10 kW/m2K is temperature measurement directly at the surface using thermocouples with a small response time. Another possibility to determine HTC in high speed quenching processes is the use of probe material that provide higher thermal conductivity than steel, such as copper with about 27 times higher heat conductivity compared to austenitic steel. Higher heat conductivity of the specimen to be quenched lowers the temperature gradients within the specimen and the cooling rates. Therefore, measurements with commonly used sheathed thermocouples are feasible. Both techniques for HTC-evaluation in rapid quenching process have been tested. The resulting HTC values will be compared with HTC data from numerical heat and fluid flow calculations and from empirical equations. Results of these evaluations show that heat transfer coefficients of about 50 kW/m2K can be achieved by high speed quenching.
Therapy of acromegalic patients exacerbated by concomitant type 2 diabetes requires higher pegvisomant doses to normalise IGF1 levels
Authors: Droste Michael , Domberg Julia , Buchfelder Michael , Mann Klaus , Schwanke Anja , Stalla Günter , Strasburger Christian J
Published: June 2014

Objective

Acromegaly is associated with an increased prevalence of glucose metabolism disorders. Clinically confirmed diabetes mellitus is observed in approximately one quarter of all patients with acromegaly and is known to have a worse prognosis in these patients.

Design

Of 514 acromegalic patients treated with pegvisomant and recorded in the German Cohort of ACROSTUDY, 147 had concomitant diabetes mellitus. We analysed these patients in an observational study and compared patients with and without concomitant diabetes.

Results

Under treatment with pegvisomant, patients with diabetes mellitus rarely achieved normalisation (64% in the diabetic cohort vs 75% in the non-diabetic cohort,P=0.04) for IGF1. Diabetic patients normalised for IGF1 required higher pegvisomant doses (18.9 vs 15.5 mg pegvisomant/day,P<0.01). Furthermore, those diabetic patients requiring insulin therapy showed a tendency towards requiring even higher pegvisomant doses to normalise IGF1 values than diabetic patients receiving only oral treatment (22.8 vs 17.2 mg pegvisomant/day,P=0.11).

Conclusions

Hence, notable interdependences between the acromegaly, the glucose metabolism of predisposed patients and their treatment with pegvisomant were observed. Our data support recent findings suggesting that intra-portal insulin levels determine the GH receptor expression in the liver underlined by the fact that patients with concomitant diabetes mellitus, in particular those receiving insulin therapy, require higher pegvisomant doses to normalise IGF1. It is therefore important to analyse various therapy modalities to find out whether they influence the associated diabetes mellitus and/or whether the presence of diabetes mellitus influences the treatment results of an acromegaly therapy.
Multifunctional RNA Processing Protein SRm160 Induces Apoptosis and Regulates Eye and Genital Development in Drosophila
Authors: Fan Yu-Jie , Gittis Aryn H , Juge François , Qiu Chen , Xu Yong-Zhen , Rabinow Leonard
Published: June 2014

SRm160 is an SR-like protein implicated in multiple steps of RNA processing and nucleocytoplasmic export. Although its biochemical functions have been extensively described, its genetic interactions and potential participation in signaling pathways remain largely unknown, despite the fact that it is highly phosphorylated in both mammalian cells and Drosophila. To begin elucidating the functions of the protein in signaling and its potential role in developmental processes, we characterized mutant and overexpression SRm160 phenotypes in Drosophila and their interactions with the locus encoding the LAMMER protein kinase, Doa. SRm160 mutations are recessive lethal, while its overexpression generates phenotypes including roughened eyes and highly disorganized internal eye structure, which are due at least in part to aberrantly high levels of apoptosis. SRm160 is required for normal somatic sex determination, since its alleles strongly enhance a subtle sex transformation phenotype induced by Doa kinase alleles. Moreover, modification of SRm160 by DOA kinase appears to be necessary for its activity, since Doa alleles suppress phenotypes induced by SRm160 overexpression in the eye and enhance those in genital discs. Modification of SRm160 may occur through direct interaction because DOA kinase phosphorylates it in vitro. Remarkably, SRm160 protein was concentrated in the nuclei of precellular embryos but was very rapidly excluded from nuclei or degraded coincident with cellularization. Also of interest, transcripts are restricted almost exclusively to the developing nervous system in mature embryos.
The Histone Acetyltransferase GcnE (GCN5) Plays a Central Role in the Regulation ofAspergillusAsexual Development
Authors: Cánovas David , Marcos Ana T , Gacek Agnieszka , Ramos María S , Gutiérrez Gabriel , Reyes-Domínguez Yazmid , Strauss Joseph
Published: June 2014

Acetylation of histones is a key regulatory mechanism of gene expression in eukaryotes. GcnE is an acetyltransferase of Aspergillus nidulans involved in the acetylation of histone H3 at lysine 9 and lysine 14. Previous works have demonstrated that deletion of gcnE results in defects in primary and secondary metabolism. Here we unveil the role of GcnE in development and show that a ∆gcnE mutant strain has minor growth defects but is impaired in normal conidiophore development. No signs of conidiation were found after 3 days of incubation, and immature and aberrant conidiophores were found after 1 week of incubation. Centroid linkage clustering and principal component (PC) analysis of transcriptomic data suggest that GcnE occupies a central position in Aspergillus developmental regulation and that it is essential for inducing conidiation genes. GcnE function was found to be required for the acetylation of histone H3K9/K14 at the promoter of the master regulator of conidiation, brlA, as well as at the promoters of the upstream developmental regulators of conidiation flbA, flbB, flbC, and flbD (fluffy genes). However, analysis of the gene expression of brlA and the fluffy genes revealed that the lack of conidiation originated in a complete absence of brlA expression in the ∆gcnE strain. Ectopic induction of brlA from a heterologous alcA promoter did not remediate the conidiation defects in the ∆gcnE strain, suggesting that additional GcnE-mediated mechanisms must operate. Therefore, we conclude that GcnE is the only nonessential histone modifier with a strong role in fungal development found so far.
Chromatin Organization and Remodeling of Interstitial Telomeric Sites During Meiosis in the Mongolian Gerbil (Meriones unguiculatus)
Authors: de la Fuente Roberto , Manterola Marcia , Viera Alberto , Parra María Teresa , Alsheimer Manfred , Rufas Julio S , Page Jesús
Published: June 2014

Telomeric DNA repeats are key features of chromosomes that allow the maintenance of integrity and stability in the telomeres. However, interstitial telomere sites (ITSs) can also be found along the chromosomes, especially near the centromere, where they may appear following chromosomal rearrangements like Robertsonian translocations. There is no defined role for ITSs, but they are linked to DNA damage-prone sites. We were interested in studying the structural organization of ITSs during meiosis, a kind of cell division in which programmed DNA damage events and noticeable chromatin reorganizations occur. Here we describe the presence of highly amplified ITSs in the pericentromeric region of Mongolian gerbil (Meriones unguiculatus) chromosomes. During meiosis, ITSs show a different chromatin conformation than DNA repeats at telomeres, appearing more extended and accumulating heterochromatin markers. Interestingly, ITSs also recruit the telomeric proteins RAP1 and TRF1, but in a stage-dependent manner, appearing mainly at late prophase I stages. We did not find a specific accumulation of DNA repair factors to the ITSs, such as γH2AX or RAD51 at these stages, but we could detect the presence of MLH1, a marker for reciprocal recombination. However, contrary to previous reports, we did not find a specific accumulation of crossovers at ITSs. Intriguingly, some centromeric regions of metacentric chromosomes may bind the nuclear envelope through the association to SUN1 protein, a feature usually performed by telomeres. Therefore, ITSs present a particular and dynamic chromatin configuration in meiosis, which could be involved in maintaining their genetic stability, but they additionally retain some features of distal telomeres, provided by their capability to associate to telomere-binding proteins.
How Population Growth Affects Linkage Disequilibrium
Authors: Rogers Alan R
Published: June 2014

The “LD curve” relates the linkage disequilibrium (LD) between pairs of nucleotide sites to the distance that separates them along the chromosome. The shape of this curve reflects natural selection, admixture between populations, and the history of population size. This article derives new results about the last of these effects. When a population expands in size, the LD curve grows steeper, and this effect is especially pronounced following a bottleneck in population size. When a population shrinks, the LD curve rises but remains relatively flat. As LD converges toward a new equilibrium, its time path may not be monotonic. Following an episode of growth, for example, it declines to a low value before rising toward the new equilibrium. These changes happen at different rates for different LD statistics. They are especially slow for estimates of σd2, which therefore allow inferences about ancient population history. For the human population of Europe, these results suggest a history of population growth.
Gross Motor Deficits in Children Prenatally Exposed to Alcohol: A Meta-analysis
Authors: Lucas Barbara R. , Latimer Jane , Pinto Rafael Z. , Ferreira Manuela L. , Doney Robyn , Lau Mandy , Jones Taryn , Dries Danielle , Elliott Elizabeth J.
Published: June 2014

BACKGROUND AND OBJECTIVES:

Gross motor (GM) deficits are often reported in children with prenatal alcohol exposure (PAE), but their prevalence and the domains affected are not clear. The objective of this review was to characterize GM impairment in children with a diagnosis of fetal alcohol spectrum disorder (FASD) or “moderate” to “heavy” maternal alcohol intake.

METHODS:

A systematic review with meta-analysis was conducted. Medline, Embase, Allied and Complementary Medicine Database, Cumulative Index to Nursing and Allied Health Literature, PsycINFO, PEDro, and Google Scholar databases were searched. Published observational studies including children aged 0 to ≤18 years with (1) an FASD diagnosis or moderate to heavy PAE, or a mother with confirmed alcohol dependency or binge drinking during pregnancy, and (2) GM outcomes obtained by using a standardized assessment tool. Data were extracted regarding participants, exposure, diagnosis, and outcomes by using a standardized protocol. Methodological quality was evaluated by using Strengthening the Reporting of Observational Studies in Epidemiology guidelines.

RESULTS:

The search recovered 2881 articles of which 14 met the systematic review inclusion criteria. The subjects’ mean age ranged from 3 days to 13 years. Study limitations included failure to report cutoffs for impairment, nonstandardized reporting of PAE, and small sample sizes. The meta-analysis pooled results (n = 10) revealed a significant association between a diagnosis of FASD or moderate to heavy PAE and GM impairment (odds ratio: 2.9; 95% confidence interval: 2.1–4.0). GM deficits were found in balance, coordination, and ball skills. There was insufficient data to determine prevalence.

CONCLUSIONS:

The significant results suggest evaluation of GM proficiency should be a standard component of multidisciplinary FASD diagnostic services.
Classification System for the Sudden Unexpected Infant Death Case Registry and its Application
Authors: Shapiro-Mendoza Carrie K. , Camperlengo Lena , Ludvigsen Rebecca , Cottengim Carri , Anderson Robert N. , Andrew Thomas , Covington Theresa , Hauck Fern R. , Kemp James , MacDorman Marian
Published: June 2014

Sudden unexpected infant deaths (SUID) accounted for 1 in 3 postneonatal deaths in 2010. Sudden infant death syndrome and accidental sleep-related suffocation are among the most frequently reported types of SUID. The causes of these SUID usually are not obvious before a medico-legal investigation and may remain unexplained even after investigation. Lack of consistent investigation practices and an autopsy marker make it difficult to distinguish sudden infant death syndrome from other SUID. Standardized categories might assist in differentiating SUID subtypes and allow for more accurate monitoring of the magnitude of SUID, as well as an enhanced ability to characterize the highest risk groups. To capture information about the extent to which cases are thoroughly investigated and how factors like unsafe sleep may contribute to deaths, CDC created a multistate SUID Case Registry in 2009. As part of the registry, the Centers for Disease Control and Prevention developed a classification system that recognizes the uncertainty about how suffocation or asphyxiation may contribute to death and that accounts for unknown and incomplete information about the death scene and autopsy. This report describes the classification system, including its definitions and decision-making algorithm, and applies the system to 436 US SUID cases that occurred in 2011 and were reported to the registry. These categories, although not replacing official cause-of-death determinations, allow local and state programs to track SUID subtypes, creating a valuable tool to identify gaps in investigation and inform SUID reduction strategies.
Omega-3 Long-Chain Polyunsaturated Fatty Acids for Extremely Preterm Infants: A Systematic Review
Authors: Zhang Peiyin , Lavoie Pascal M. , Lacaze-Masmonteil Thierry , Rhainds Marc , Marc Isabelle
Published: June 2014

BACKGROUND AND OBJECTIVE:

Omega-3 long chain polyunsaturated fatty acid (LCPUFA) exposure can be associated with reduced neonatal morbidities. We systematically review the evidence for the benefits of omega-3 LCPUFAs for reducing neonatal morbidities in extremely preterm infants.

METHODS:

Data sources were PubMed, Embase, Center for Reviews and Dissemination, and the Cochrane Register of Controlled Trials. Original studies were selected that included infants born at <29 weeks’ gestation, those published until May 2013, and those that evaluated the relationship between omega-3 LCPUFA supplementation and major adverse neonatal outcomes. Data were extracted on study design and outcome. Effect estimates were pooled.

RESULTS:

Of the 1876 studies identified, 18 randomized controlled trials (RCTs) and 6 observational studies met the defined criteria. No RCT specifically targeted a population of extremely preterm infants. Based on RCTs, omega-3 LCPUFA was not associated with a decreased risk of bronchopulmonary dysplasia in infants overall (pooled risk ratio [RR] 0.97, 95% confidence interval [CI] 0.82–1.13], 12 studies, n = 2809 infants); however, when considering RCTs that include only infants born at ≤32 weeks’ gestation, a trend toward a reduction in the risk of bronchopulmonary dysplasia (pooled RR 0.88, 95% CI 0.74–1.05, 7 studies, n = 1156 infants) and a reduction in the risk of necrotizing enterocolitis (pooled RR 0.50, 95% CI 0.23–1.10, 5 studies, n = 900 infants) was observed with LCPUFA.

CONCLUSIONS:

Large-scale interventional studies are required to determine the clinical benefits of omega-3 LCPUFA, specifically in extremely preterm infants, during the neonatal period.
Hypertension Screening Using Blood Pressure to Height Ratio
Authors: Xi Bo , Zhang Meixian , Zhang Tao , Liang Yajun , Li Shuangshuang , Steffen Lyn M.
Published: June 2014

OBJECTIVES:

The definition of hypertension in children is too complex to be used by medical professionals and children and their parents because of the age-, gender-, and height-specific blood pressure (BP) algorithm. The aim of this study was to simplify the pediatric BP percentile references using BP to height ratio (BPHR, equal to BP/height) for screening for prehypertension and hypertension in Chinese children.

METHODS:

Data were obtained from the China Health and Nutrition Survey, which was conducted from 1991 to 2009 and included 11 661 children aged 6 to 17 years with complete data on age, gender, height, and BP values. Receiver operating characteristic curve analysis was performed to assess the performance of systolic BPHR (SBPHR) and diastolic BPHR (DBPHR) for screening for pediatric prehypertension and hypertension.

RESULTS:

The optimal thresholds for defining prehypertension were 0.81 in children aged 6 to 11 years and 0.70 in adolescents aged 12 to 17 years for SBPHR and 0.52 in children and 0.46 in adolescents for DBPHR, respectively. The corresponding values for hypertension were 0.84, 0.78, 0.55, and 0.50, respectively. The negative predictive values were much higher (all ≥99%) for prehypertension and hypertension, although the positive predictive values were relatively lower, ranging from 13% to 75%.

CONCLUSIONS:

BPHR index is simple and accurate for screening for prehypertension and hypertension in Chinese children aged 6 to 17 years and can be used for early screening or treating Chinese children with hypertension.
Electromigration Reliability of Electroplated Gold Interconnects
Authors: Kilgore Steve H. , Schroder Dieter K.
Published: June 2014

The electromigration lifetimes of a very large quantity of passivated electroplated Au interconnects were measured utilizing high-resolution in-situ resistance monitoring equipment. Application of moderate accelerated stress conditions with current density limited to 2 MA/cm2 and oven temperatures in the range of 300°C to 375°C prevented large Joule-heated temperature gradients and electrical overstress failures. A Joule-heated Au film temperature increase of 10°C on average was determined from measured temperature coefficients of resistance (TCRs). A failure criterion of 50% resistance degradation was selected to avoid thermal runaway and catastrophic open circuit failures. All Au lifetime distributions followed log-normal statistics. An activation energy of 0.80 ± 0.05 eV was measured from constant-current electromigration tests at multiple temperatures. A current density exponent of 1.91 ± 0.03 was extracted from multiple current densities at a single constant temperature.
Heat resistant polymer electrolyte for enhanced organic electrochromic windows based on poly (3,3-dimethyl-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine)
Authors: Anandan Nishita , Kim Sooyeun , Taya Minoru
Published: June 2014

Electrochromic Windows(ECWs) have the potential to save energy through dynamic control of light and solar energy entering a room (via solar heat gain coefficient control). ECWs have been developed as an optical shutter in airplane, building and automobile applications. An ECW is composed of three components, a working electrode based on electrochromic materials, a counter electrode based on ion storage materials and the electrolyte as an ionic conducting layer. Organic ECWs have been gaining popularity due to easy and cost effective manufacturing, availability of wide range of colors, high optical contrast and flexibility in design. However there are challenges in commercialization and application of organic ECWs. The application of ECWs as a sunroof in automobiles demands operation in harsh environment conditions like elevated temperature. Consequently the University of Washington, Center for Intelligent Materials and Systems has been developing a heat resistant organic ECW that can be operated at elevated temperatures maintaining high optical contrast, fast switching speed, optical color memory and electrochemical stability. The proposed design is an ECW based on poly (3,3-dimethyl-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine),PPRODOT-Me2 as a working electrode, V2O5-TiO2 composite materials as a counter electrode and poly(ethylene imine) based electrolyte. The ionic conductivity of the electrolyte was calculated through complex impedance method and temperature dependence of the electrolyte was determined using environment test chamber to control a temperature range of 15 to 80o Celsius for 100 hours. A 76 × 76 mm2 ECW was developed and the optical transmittance change was observed by Chronoamperomerty and Time course measurement. The electrochemical stability of the window was monitored using cyclic voltammetry. The developed electrochromic window showed good optical contrast, electrochemical stability and fast response time after testing at elevated temperatures for 100 hours.
Self-assembled Carbon Nanotube-DNA Hybrids at the Nanoscale: Morphological and Conductive Properties Probed by Atomic Force Microscopy
Authors: Santonicola M. Gabriella , Laurenzi Susanna , Schön Peter M.
Published: June 2014

Our research is focused on the engineering of novel, highly sensitive and miniaturized hybrid materials from carbon nanotubes (CNTs) and DNA molecules for applications in biosensors and medical devices. These hybrid sensors allow for a high degree of miniaturization, a key factor in the design of lightweight components while maintaining the advantages of in-situ and real-time analysis capabilities. In the first phase of the sensor design process, we investigated the structural and electrical properties of the supramolecular complexes made of amide-functionalized CNTs and double-stranded DNA. The solubilization properties of the hybrid nanotubes in aqueous solutions with different concentrations of DNA were studied, and an optimal ratio of nanotubes and biomolecules to achieve a good level of dispersion was found. Complexes formed in aqueous solution from CNTs and DNA are highly stable and maintain their properties up to one month from preparation. The morphology of the CNT-DNA composites was investigated at the nanoscale level using atomic force microscopy (AFM) and electron microscopy (SEM). Results from these experiments show the strong affinity between the surface of the amide-functionalized CNTs and the DNA strands. Further, the CNT-DNA films were investigated by atomic force microscopy in the PeakForce TUNA mode to assess the suitability of this technique in determining the local conductive properties of the hybrid films.
Electrochemical Reduction of CO2 using Copper Oxide Nanoparticles supported on Glassy Carbon Electrodes
Authors: Griffin Gregory L. , Bugayong Joel
Published: June 2014

We have studied the electrochemical reduction of CO2 using Cu2O nanoparticles deposited on planar electrodes. Nanoparticles are prepared in aqueous solution by chemical reduction of CuCl2 using ascorbic acid with polyethylene glycol surfactant. The particles are then re-suspended in ethanol with added Nafion binder and brush-coated onto glassy carbon substrates. The CO2 electroreduction activity is measured in KHCO3 electrolyte under flowing CO2 using a two-compartment electrochemical cell. Product formation rates are determined using gas chromatography; major gas phase products include CO, H2, C2H4, and CH4, while liquid phase products include C2H5OH and 1-C3H5OH. The observed product distribution agrees with results obtained previously using similar Cu2O particles deposited on carbon fiber paper supports, as well as Cu2O catalysts prepared by electrodeposition or thermal oxidation. In particular, the catalysts produce a much higher ratio of C2H4 to CH4 than observed using polycrystalline Cu foil. The potential dependence of the formation rates for hydrocarbon and alcohol products is roughly two times greater than for H2 and CO formation. Both XRD and SEM measurements confirm the Cu2O nanoparticles undergo at least partial reduction to Cu metal under CO2 reduction conditions, accompanied by significant surface morphological changes. Thus the kinetic results are consistent with current models that the increased C2H4/CH4 ratio is due to the presence of a more open atomic structure on the freshly reduced Cu surfaces.
The Road to Commercialization of Vapor-Phase-Grown Diamond
Authors: Shikata Shinichi
Published: June 2014

Considering all materials, diamond has many superior properties such as elastic constant (hardness), thermal conductivity, transparency to optical visible light and x-rays, a wide-bandgap semiconductor, and negative electron affinity. These properties lead to various applications in many industries. Because of the recent successful development of vapor-phase-growth technology, large-area diamond is available at a low manufacturing cost. However the commercialization of diamond at this stage is limited to tools, speaker diaphragms, heatsinks, and optical windows. For each application, diamond utilization is limited.

In this article, three avenues on the road to commercialization of vapor-phase-grown diamond will be discussed. The categories appear in Table I with the properties of diamond and its applications. First, applications already commercialized are briefly reviewed, and the requirements for expanding their market are discussed. Second, the technologies and applications coming in the near term are introduced. Last, future candidate applications for diamond are introduced along with technical obstacles to be overcome.
Polymeric and Organic Electronic Materials: From Scientific Curiosity to Applications
Authors: Epstein Arthur J. , Yang Yang
Published: June 2014

While polymers and organic materials have been known and utilized broadly for many decades, finding such materials with the intrinsic properties of semiconductors and metals is a relatively recent phenomenon. The report in 1977 about doping polyacetylene to achieve relatively high conductivity opened up important new vistas for chemistry and physics, and for technology in general. This report recognized that a key feature of the electronic polymers and organic materials was a backbone consisting of alternating single and double bonds resulting in a “π-conjugated network.” This in turn led to a relatively small energy gap, enabling the appearance of both semiconducting and metallic properties.

Initially these polymers were unstable in air and not readily processed. Over the past decade, major advances have occurred in the synthesis of new forms of conducting and semiconducting polymers that enable processing under a broad range of conditions including organic solvents, inorganic solvents, and aqueous media. There are even meltprocessable versions of some of the electronic polymers.

A prime focus of the field has been the determination of the mechanisms for charge conduction and the intrinsic conductivity of these fascinating materials, especially doped polymers. In the past decade, interest has increased in the semiconducting (generally undoped) forms of these polymers and organic materials, including their photophysics and their use in a wide variety of devices. The reports of light-emitting devices fabricated from molecular and oligomeric constituents in the mid-1980s and from polymeric constituents in 1990 stimulated interest in this area of research.