bluuebunny/crossref_metadata_2025 huggingface dataset:
Equity, Bonds, Institutional Debt and Economic Growth: Evidence from South Africa
Authors: Fanta Ashenafi Beyene , Makina Daniel
Published: February 2016

We examine the finance‐growth nexus in South Africa accounting for the role of bond markets, stock markets, and bank and non‐bank financial intermediaries using a vector autoregressive technique. Extant empirical literature has largely accounted for only banks and stock markets, ignoring bond market and non‐bank financial intermediaries. We find that bond market development affects economic growth in South Africa, and no similar effect is observed for the bank and non‐bank financial intermediaries and the stock market. Our finding shows that examination of individual elements of the financial system is important in understanding the unique effect of each on growth. The observation that the bond market rather than stock market, bank and non‐bank institutions promote economic growth in South Africa induces an intriguing question as to what unique roles bond markets play that the intermediaries and equity market are unable to play.
Exponential Family Techniques for the Lognormal Left Tail
Authors: Asmussen Søren , Jensen Jens Ledet , Rojas‐Nandayapa Leonardo
Published: February 2016

LetXbe lognormal(μ,σ2) with densityf(x); letθ> 0 and define. We study properties of the exponentially tilted density (Esscher transform)fθ(x) = e−θxf(x)/L(θ), in particular its moments, its asymptotic form asθ→∞and asymptotics for the saddlepointθ(x) determined by. The asymptotic formulas involve the Lambert W function. The established relations are used to provide two different numerical methods for evaluating the left tail probability of the sum of lognormalsSn=X1+⋯+Xn: a saddlepoint approximation and an exponential tilting importance sampling estimator. For the latter, we demonstrate logarithmic efficiency. Numerical examples for the cdfFn(x) and the pdffn(x) ofSnare given in a range of values ofσ2,nandxmotivated by portfolio value‐at‐risk calculations.
Intersectional Individuality: Georg Simmel's Concept of “The Intersection of Social Circles” and the Emancipation of Women
Authors: Stoetzler Marcel
Published: February 2016

Georg Simmel's “The intersection of social circles,” a chapter in his 1908Sociology, contains discussions of class, religion, ethnic, and gender relations that are highly relevant to contemporary sociological concerns. Simmel's argument is based on a notion of historical dynamic that interprets increasingly complex intersectionality as a sign of progressing civilization. The article establishes how Simmel describes “the intersection of social circles” and then looks at Simmel's account through the concept of “intersectionality” as developed in contemporary feminist theory. The article suggests that although some aspects of Simmel's account of women in modernity are incompatible with contemporary feminism, the shared use of the same image, “intersection,” in Simmel and in contemporary feminist theory is the symptom of a shared concern with a particular aspect of the complexity of modern society. In Simmel, the increasing density of the intersections of social circles points to the increasingly complex individuality of modern subjects, whereas the use of the same image in contemporary feminist theory is part of a critique of inequality and oppression in the same modern society whose advent Simmel celebrated. Intersectionality is a characteristic of modern society that first became visible more than a century ago and has meanwhile become ever the more a signature of modernity.
Revised classification and evolution of leucotrichiine microcaddisflies (Trichoptera: Hydroptilidae) based on morphological and molecular data
Authors: SANTOS ALLAN P. M. , NESSIMIAN JORGE L. , TAKIYA DANIELA M.
Published: February 2016

Hydroptilidae constitute the most diverse caddisfly family, with over 2000 species known from every habitable continent. Leucotrichiinae are exclusively New World microcaddisflies, currently including over 200 species and 17 genera. Phylogenetic analyses of Leucotrichiinae relationships based on 114 morphological characters and 2451 molecular characters from DNA sequences were conducted. DNA sequences analysed were from one mitochondrial gene, cytochrome oxidase I (653 bp), and four nuclear genes, carbamoylphosphate synthase (802 bp), elongation factor 1α (352 bp), histone 3 (308 bp) and 28S rDNA (336 bp). The morphological matrix included 94 taxa (with representatives of all included genera) and the molecular matrix included 62 taxa. Individual and combined datasets were analysed under parsimony and Bayesian inference. In addition, a relaxed molecular clock divergence time estimate was conducted to determine the age of the subfamily and major lineages. All Bayesian inference analyses strongly suggest a monophyletic Leucotrichiinae, which initially diverged at approximately 124 Ma into two monophyletic groups of genera. These groups are herein elevated to tribal status, Alisotrichiini trib.n. and Leucotrichiini Flint sensu n. Several genera of Leucotrichiini were not recovered as monophyletic clades and some nomenclatural changes are proposed to reflect their phylogenetic history. These include the synonymy of Abtrichia with Peltopsyche; transfer of Betrichia hamulifera to Costatrichia; transfer of Betrichia alibrachia and Costatrichia falsa to Leucotrichia; and transfer of Costatrichia fluminensis to Acostatrichia. Additionally, Tupiniquintrichia gen.n. is described to include Peltopsyche maclachlani and Leucotrichia procera. According to our results, crown diversifications of both Alisotrichiini trib.n. (∼80 Ma) and Leucotrichiini sensu n. (∼103 Ma) occurred after complete separation of South America from Africa. Current distributions of most leucotrichiine genera are probably a result of migration from South America towards the north using the proto‐Caribbean archipelago (100 to 49 Ma).

This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:FB6A3385-323D-41AF-B4BE-E19A393A493C.
Measuring the impact of non‐monetary incentives on facility delivery in rural Zambia: a clustered randomised controlled trial
Authors: Wang P. , Connor A. L. , Guo E. , Nambao M. , Chanda‐Kapata P. , Lambo N. , Phiri C.
Published: February 2016

Objectives

In Zambia, only 56% of rural women deliver in a health facility, and improving facility delivery rates is a priority of the Zambian government. ‘Mama kit’ incentives – small packages of childcare items provided to mothers conditional on delivering their baby in a facility – may encourage facility delivery. This study measured the impact and cost‐effectiveness of a US$4 mama kit on rural facility delivery rates in Zambia.

Methods

A clustered randomised controlled trial was used to measure the impact of mama kits on facility delivery rates in thirty rural health facilities in Serenje and Chadiza districts. Facility‐level antenatal care and delivery registers were used to measure the percentage of women attending antenatal care who delivered at a study facility during the intervention period. Results from the trial were then used to model the cost‐effectiveness of mama kits at‐scale in terms of cost per death averted.

Results

The mama kits intervention resulted in a statistically significant increase in facility delivery rates. The multivariate logistic regression found that the mama kits intervention increased the odds of delivering at a facility by 63% (P‐value < 0.01, 95% CI: 29%, 106%), or an increase of 9.9 percentage points, yielding a cost‐effectiveness of US$5183 per death averted.

Conclusions

This evaluation confirms that low‐cost mama kits can be a cost‐effective intervention to increase facility delivery rates in rural Zambia. Mama kits alone are unlikely to completely solve safe delivery challenges but should be embedded in larger maternal and child health programmes.
Reducing the age of transfused red blood cells in hospitals: ordering and allocation policies
Authors: Sarhangian V. , Abouee‐Mehrizi H. , Baron O. , Berman O. , Heddle N. M. , Barty R.
Published: February 2016

Background

Although recent randomized controlled trials have not found increased risk of morbidity/mortality with older red blood cells (RBCs), several large trials will be completed soon providing power to detect smaller risks if indeed they exist. Hence, there may still be a need for inventory management policies that could reduce the age of transfused RBCs without compromising availability or resulting in excessive outdates.

Materials and Methods

We developed a computer simulation model based on data from an acute care hospital in Hamilton, Ontario. We evaluated and compared the performance of certain practical ordering and allocation policies in terms of outdate rate, shortage rate and the distribution of the age of issued RBCs.

Results

During the 1‐year period for which we analysed the data, 10349 RBC units were transfused with an average issue age of 20·7 days and six units were outdated (outdate rate: 0·06%). Adopting a strict first in, first out (FIFO) allocation policy and an order‐up‐to ordering policy with target levels set to five times the estimated daily demand for each blood type, reduced the average issue age by 29·4% (to 14·6 days), without an increase in the outdate rate (0·05%) or resulting in any unmet demand. Further reduction of issue age without a significant increase in outdate rate was observed when adopting non‐FIFO threshold‐based allocation policies and appropriately adjusting the order‐up‐to levels.

Conclusion

A significant reduction of issue age could be possible, without compromising availability or resulting in excessive outdates, by properly adjusting the ordering and allocation policies at the hospital level.
Lessons from computer simulations of ablation of atrial fibrillation
Authors: Jacquemet Vincent
Published: February 2016

This paper reviews the simulations of catheter ablation in computer models of the atria, from the first attempts to the most recent anatomical models. It describes how postulated substrates of atrial fibrillation can be incorporated into mathematical models, how modelling studies can be designed to test ablation strategies, what their current trade‐offs and limitations are, and what clinically relevant lessons can be learnt from these simulations. Drawing a parallel between clinical and modelling studies, six ablation targets are considered: pulmonary vein isolation, linear ablation, ectopic foci, complex fractionated atrial electrogram, rotors and ganglionated plexi. The examples presented for each ablation target illustrate a major advantage of computer models, the ability to identify why a therapy is successful or not in a given atrial fibrillation substrate. The integration of pathophysiological data to create detailed models of arrhythmogenic substrates is expected to solidify the understanding of ablation mechanisms and to provide theoretical arguments supporting substrate‐specific ablation strategies.

image
A Detailed Uncertainty Analysis of Adiabatic Film Cooling Effectiveness Measurements Using Pressure-Sensitive Paint
Authors: Natsui Greg , Little Zachary , Kapat Jayanta S. , Dees Jason E. , Laskowski Gregory
Published: February 2016

Pressure-sensitive paint (PSP) can be a powerful tool in measuring the adiabatic film cooling effectiveness. There are two distinct sources of error for this measurement technique: the ability to experimentally obtain the data and the validity of the heat and mass transfer analogy for the problem being studied. This paper will assess the experimental aspect of this PSP measurement specifically for film cooling applications. Experiments are conducted in an effort to quantifiably bound expected errors associated with temperature nonuniformities in testing and photodegradation effects. Results show that if careful experimental procedures are put in place, both of these effects can be maintained to have less than 0.022 impact on effectiveness. Through accurate semi in situ calibration down to 4% atmospheric pressure, the near-hole distribution of effectiveness is measured with high accuracy. PSP calibrations are performed for multiple coupons, over multiple days. In addition, to reach a partial pressure of zero the calibration vessel was purged of all air by flowing CO2. The primary contribution of this paper lies in the uncertainty analysis performed on the PSP measurement technique. A thorough uncertainty analysis is conducted and described, in order to completely understand the presented measurements and any shortcomings of the PSP technique. This quantification results in larger, albeit more realistic, values of uncertainty and helps provide a better understanding of film cooling effectiveness measurements taken using the PSP technique. The presented uncertainty analysis takes into account all random error sources associated with sampling and calibration, from intensities to effectiveness. Adiabatic film cooling effectiveness measurements are obtained for a single row of film cooling holes inclined at 20 deg, with CO2 used as coolant. Data are obtained for six blowing ratios. Maps of uncertainty corresponding to each effectiveness profile are available for each test case. These maps show that the uncertainty varies spatially over the test surface and high effectiveness corresponds to low uncertainty. The noise floors can be as high as 0.04 at effectiveness levels of 0. Day-to-day repeatability is presented for each blowing ratio and shows that laterally averaged effectiveness data are repeatable within 0.02 effectiveness.
Atomic layer deposition of two dimensional MoS2 on 150 mm substrates
Authors: Valdivia Arturo , Tweet Douglas J. , Conley John F.
Published: February 2016

Low temperature atomic layer deposition (ALD) of monolayer to few layer MoS2 uniformly across 150 mm diameter SiO2/Si and quartz substrates is demonstrated. Purge separated cycles of MoCl5 and H2S precursors are used at reactor temperatures of up to 475 °C. Raman scattering studies show clearly the in-plane (E12g) and out-of-plane (A1g) modes of MoS2. The separation of the E12g and A1g peaks is a function of the number of ALD cycles, shifting closer together with fewer layers. X-ray photoelectron spectroscopy indicates that stoichiometry is improved by postdeposition annealing in a sulfur ambient. High resolution transmission electron microscopy confirms the atomic spacing of monolayer MoS2 thin films.
Detecting the thickness mode frequency in a concrete plate using backward wave propagation
Authors: Bjurström Henrik , Ryden Nils
Published: February 2016

Material stiffness and plate thickness are the two key parameters when performing quality assurance/quality control on pavement structures. In order to estimate the plate thickness non-destructively, the Impact Echo (IE) method can be utilized to extract the thickness resonance frequency. An alternative to IE for estimating the thickness resonance frequency of a concrete plate, and to subsequently enable thickness determination, is presented in this paper. The thickness resonance is often revealed as a sharp peak in the frequency spectrum when contact receivers are used in seismic testing. Due to a low signal-to-noise ratio, IE is not ideal when using non-contact microphone receivers. In studying the complex Lamb wave dispersion curves at a frequency infinitesimally higher than the thickness frequency, it is seen that two counter-directed waves occur at the same frequency but with phase velocities in opposite directions. Results show that it is possible to detect the wave traveling with a negative phase velocity using both accelerometers and air-coupled microphones as receivers. This alternative technique can possibly be used in non-contact scanning measurements based on air-coupled microphones.
Taking race out of human genetics
Authors: Yudell Michael , Roberts Dorothy , DeSalle Rob , Tishkoff Sarah
Published: February 2016

Engaging a century-long debate about the role of race in science
Biophysical climate impacts of recent changes in global forest cover
Authors: Alkama Ramdane , Cescatti Alessandro
Published: February 2016

It's not only the carbon in the trees

Forest loss affects climate not just because of the impacts it has on the carbon cycle, but also because of how it affects the fluxes of energy and water between the land and the atmosphere. Evaluating global impact is complicated because deforestation can produce different results in different climate zones, making it hard to determine large-scale trends rather than more local ones. Alkama and Cescatti conducted a global assessment of the biophysical effects of forest cover change. Forest loss amplifies diurnal temperature variations, increases mean and maximum air temperatures, and causes a significant amount of warming when compared to CO
2
emission from land-use change.

Science
, this issue p.
600
Deformed wing virus is a recent global epidemic in honeybees driven by
Varroa
mites
Authors: Wilfert L. , Long G. , Leggett H. C. , Schmid-Hempel P. , Butlin R. , Martin S. J. M. , Boots M.
Published: February 2016

Varroa
-vectored virus pandemic

Bees are facing several threats that are causing population collapses. Wilfert
et al.
found that European honey bees are the primary source of deformed wing virus (DWV) (see the Perspective by Villalobos). However, paradoxically, transmission between bees is inefficient. It seems that parasitic mites can facilitate virus transmission. European honeybees acquired the rapidly spreading
Varroa
mite from Asian honey bees, possibly via the commercial exchange of queens. Not only do bees suffer direct damage from the mites, but the bees are also efficiently inoculated with DWV.

Science
, this issue p.
594
; see also p.
554
Structures of aminoarabinose transferase ArnT suggest a molecular basis for lipid A glycosylation
Authors: Petrou Vasileios I. , Herrera Carmen M. , Schultz Kathryn M. , Clarke Oliver B. , Vendome Jérémie , Tomasek David , Banerjee Surajit , Rajashankar Kanagalaghatta R. , Belcher Dufrisne Meagan , Kloss Brian , Kloppmann Edda , Rost Burkhard , Klug Candice S. , Trent M. Stephen , Shapiro Lawrence , Mancia Filippo
Published: February 2016

A bacterial defense mechanism

Polymyxins are antibiotics that disrupt the bacterial cell membrane and are used to treat multidrug-resistant infections. A bacterial enzyme called ArnT can mediate resistance to polymyxins by transferring a sugar group from a lipid carrier to lipid A, a component of the bacterial outer membrane. Petrou
et al.
described structures of ArnT alone and in complex with a lipid carrier and identified a cavity where lipid A probably binds. Insights into the enzyme mechanism could be exploited to design drugs that combat polymyxin resistance.

Science
, this issue p.
608
CLK2 inhibition ameliorates autistic features associated with SHANK3 deficiency
Authors: Bidinosti Michael , Botta Paolo , Krüttner Sebastian , Proenca Catia C. , Stoehr Natacha , Bernhard Mario , Fruh Isabelle , Mueller Matthias , Bonenfant Debora , Voshol Hans , Carbone Walter , Neal Sarah J. , McTighe Stephanie M. , Roma Guglielmo , Dolmetsch Ricardo E. , Porter Jeffrey A. , Caroni Pico , Bouwmeester Tewis , Lüthi Andreas , Galimberti Ivan
Published: February 2016

Signal problems in autism spectrum disorder

Autism spectrum disorders have many causes. Bidinosti
et al.
studied Phelan-McDermid syndrome (PMDS), one of the symptoms of which can be autism (see the Perspective by Burbach). The authors used neurons derived from these patients, as well as from mice, with the culprit gene disrupted and found that a chain of intracellular signals becomes imbalanced. Signaling and behavioral symptoms could be improved by a small-molecule therapeutic that inhibits a key kinase.

Science
, this issue p.
1199
; see also p.
1153
The mite that jumped, the bee that traveled, the disease that followed
Authors: Villalobos Ethel M.
Published: February 2016

Global expansion and trade contributed to the declining health of honeybees

[Also see Report by

Wilfert
et al.

]
Aging, alopecia, and stem cells
Authors: Lei Mingxing , Chuong Cheng-Ming
Published: February 2016

Intrinsic epigenetic status and extrinsic environmental factors affect hair follicle stem cells

[Also see Research Article by

Matsumura
et al.

and Report by

Wang
et al.

]
Complete Genomic Sequence of Maize Rough Dwarf Virus, a Fijivirus Transmitted by the Small Brown Planthopper
Authors: Lv Mingfang , Xie Li , Yang Jian , Chen Jianping , Zhang Heng-Mu
Published: February 2016

The nucleotide sequences of the 10 genomic segments of an Italian isolate of maize rough dwarf virus (MRDV) were determined. This first complete genomic sequence of MRDV will help understand the phylogenetic relationships among group 2 fijiviruses and especially the closely related rice black-streaked dwarf virus, which is also found to naturally infect maize.
Two Complete Genome Sequences of Phasey Bean Mild Yellows Virus, a Novel Member of the
Luteoviridae
from Australia
Authors: Sharman Murray , Kehoe Monica , Coutts Brenda , van Leur Joop , Filardo Fiona , Thomas John
Published: February 2016

We present here the complete genome sequences of a novel polerovirus from
Trifolium subterraneum
(subterranean clover) and
Cicer arietinum
(chickpea) and compare these to a partial viral genome sequence obtained from
Macroptilium lathyroides
(phasey bean). We propose the name phasey bean mild yellows virus for this novel polerovirus.
Draft Genome Sequence of Bacillus muralis LMG 20238
T
(DSM 16288), a Spore-Forming Bacterium Isolated from Deteriorated Mural Paintings
Authors: Wang Jie-ping , Liu Bo , Liu Guo-hong , Chen Qianqian , Pan Zhizhen , Zheng Xue-fang , Chen Meichun
Published: February 2016

Bacillus muralis
LMG 20238
T
is a Gram-positive, aerobic, and spore-forming bacterium. Here, we report the 5.18-Mb draft genome sequence of
B. muralis
LMG 20238
T
, which is the first genome sequence of this species and will promote its fundamental research.
Whole-Genome Sequencing Reveals a New Genospecies of
Methylobacterium
sp. GXS13, Isolated from Vitis vinifera L. Xylem Sap
Authors: Lai Wan Xin , Gan Han Ming , Hudson André O. , Savka Michael A.
Published: February 2016

The whole-genome sequence of a new genospecies of
Methylobacterium
sp., named GXS13 and isolated from grapevine xylem sap, is reported and demonstrates potential for methylotrophy, cytokinin synthesis, and cell wall modification. In addition, biosynthetic gene clusters were identified for cupriachelin, carotenoid, and acyl-homoserine lactone using the antiSMASH server.
Pf Filamentous Phage Requires UvrD for Replication in Pseudomonas aeruginosa
Authors: Martínez Eriel , Campos-Gómez Javier
Published: February 2016

Biofilm development is a key component of the ability of
Pseudomonas aeruginosa
to evade host immune defenses and resist multiple drugs. Induction of the filamentous phage Pf, which usually is lysogenized in clinical and environmental isolates of
P. aeruginosa
, plays an important role in biofilm assembly, maturation, and dispersal. Despite the clinical relevance of Pf, the molecular biology of this phage is largely unknown. In this study, we found that rolling circle replication of Pf depends on UvrD, a DNA helicase normally involved in DNA repair. We also identified the initiator protein of Pf and found that it shares structural similarity with that of
Vibrio cholerae
phages CTXφ and VGJφ, which also use UvrD for replication. Our results reveal that, in addition to DNA repair, UvrD plays an essential role in rolling circle replication of filamentous phages among diverse bacteria genera, adding a new, previously unrecognized function of this accessory helicase.
LVIS Jr ‘shelf’ technique: an alternative to Y stent-assisted aneurysm coiling
Authors: Du Elizabeth Hai Yen , Shankar Jai Jai Shiva
Published: February 2016

Wide-necked bifurcation intracranial aneurysms have traditionally not been amenable to coil embolization with the use of a single stent due to the high risk of coil prolapse. Y-configuration double stent-assisted coil embolization (‘Y-stenting’) of this aneurysm type has been shown to have generally good clinical outcomes, although the technique is complex with various challenges described in the literature. The compliant and flexible closed-cell design of braided stents such as the LVIS Jr allows for the creation of a ‘shelf’ across the aneurysm neck sufficient to prevent coil prolapse. We describe this novel ‘shelf’ technique and present a small case series of LVIS Jr stent-assisted wide-necked bifurcation intracranial aneurysm coiling in eight patients. Our small, albeit important, case series demonstrates that the ‘shelf’ technique is feasible and safe with very good short-term clinical and angiographic outcomes, and may obviate the need for Y-stenting.
Novel Design of Collaborative Automation Platform Using Real-Time Data Distribution Service Middleware for an Optimum Process Control Environment
Authors: Sait Sadiq M. , Al-Hashim Ghalib A.
Published: February 2016

Refining and petrochemical processing facilities utilize various process control applications to raise productivity and enhance plant operation. Client–server communication model is used for integrating these highly interacting applications across multiple network layers utilized in distributed control systems. This paper presents an optimum process control environment by merging sequential and regulatory control, advanced regulatory control, multivariable control, unit-based process control, and plant-wide advanced process control into a single collaborative automation platform to ensure optimum operation of processing equipment for achieving maximum yield of all manufacturing facilities. The main control module is replaced by a standard real-time server. The input/output racks are physically and logically decoupled from the controller by converting them into distributed autonomous process interface systems. Real-time data distribution service middleware is used for providing seamless cross-vendor interoperable communication among all process control applications and distributed autonomous process interface systems. Detailed performance analysis was conducted to evaluate the average communication latency and aggregate messaging capacity among process control applications and distributed autonomous process interface systems. The overall performance results confirm the viability of the new proposal as the basis for designing an optimal collaborative automation platform to handle all process control applications. It also does not impose any inherent limit on the aggregate data messaging capacity, making it suitable for scalable automation platforms.
PRICING AND HEDGING OF ENERGY SPREAD OPTIONS AND VOLATILITY MODULATED VOLTERRA PROCESSES
Authors: BENTH FRED ESPEN , ZDANOWICZ HANNA
Published: February 2016

We derive the price of a spread option based on two assets which follow a bivariate volatility modulated Volterra (VMV) process dynamics. Such a price dynamics is particularly relevant in energy markets, modeling for example the spot price of power and gas. VMV processes are in general not semimartingales, but contain several special cases of interest in energy markets, like for example continuous-time autoregressive moving average processes. Based on a change of measure, we obtain a pricing expression based on a univariate Fourier transform of the payoff function and the characteristic function of the price dynamics. Moreover, the spread option price can be expressed in terms of the forward prices on the underlying dynamics assets. We compute a linear system of equations for the quadratic hedge for the spread option in terms of a portfolio of underlying forward contracts.
BUBBLES AND MULTIPLE-FACTOR ASSET PRICING MODELS
Authors: JARROW ROBERT
Published: February 2016

This paper derives a multiple-factor asset pricing model with asset price bubbles in an arbitrage-free, competitive, and frictionless market. As such it generalizes existing asset pricing models, all of which implicitly assume asset price bubbles do not exist. This generalization leads to two new empirical implications. The first is that positive alphas can exist in an arbitrage-free market due to the existence of asset price bubbles. These positive alphas do not represent abnormal profit opportunities. The second is that bubble risk factors can exist with positive risk premiums. The testing of these new empirical implications awaits subsequent research.
Exact Characteristic Equations in Closed-Form for Vibration of Completely Free Timoshenko Beams
Authors: Kang Jae-Hoon
Published: February 2016

Huang 1 presented first in 1961 the characteristic equations and normal mode equations for all six common types of simple, finite Timoshenko beams in closed-form. Unfortunately, there exist several errors, not typographical, in the frequency in the characteristic equations for a Timoshenko beam free at both ends. In this paper, the exact characteristic equations in closed-form for completely free Timoshenko beams are derived based on Ref. 1. In order to justify the solutions obtained by amending herein Huang’s equations, both the closed-form exact solution and the one obtained by the Ritz method will be adopted as the references. Using the characteristic equations derived by Huang 1 , we can obtain only frequencies for the flexural modes, while using the closed-form exact method and Ritz method, we can obtain frequencies for the thickness-shear modes, as well as for the bending modes. The purpose of the present study is to identify the errors in Ref. 1, correct them, and provide some numerical results.
A New Hybrid-Multiscale SSA Prediction of Non-Stationary Time Series
Authors: Ghanbarzadeh Mitra , Aminghafari Mina
Published: February 2016

Singular spectral analysis (SSA) is a non-parametric method used in the prediction of non-stationary time series. It has two parameters, which are difficult to determine and very sensitive to their values. Since, SSA is a deterministic-based method, it does not give good results when the time series is contaminated with a high noise level and correlated noise. Therefore, we introduce a novel method to handle these problems. It is based on the prediction of non-decimated wavelet (NDW) signals by SSA and then, prediction of residuals by wavelet regression. The advantages of our method are the automatic determination of parameters and taking account of the stochastic structure of time series. As shown through the simulated and real data, we obtain better results than SSA, a non-parametric wavelet regression method and Holt–Winters method.
Randomness and Earth’s Climate Variability
Authors: Levinshtein Michael , Dergachev Valentin , Dmitriev Alexander , Shmakov Pavel
Published: February 2016

Paleo-Sciences including palaeoclimatology and palaeoecology have accumulated numerous records related to climatic changes. The researchers have usually tried to identify periodic and quasi-periodic processes in these paleoscientific records. In this paper, we show that this analysis is incomplete. As follows from our results, random processes, namely processes with a single-time-constant [Formula: see text] (noise with a Lorentzian noise spectrum), play a very important and, perhaps, a decisive role in numerous natural phenomena. For several of very important natural phenomena the characteristic time constants [Formula: see text] are very similar and equal to [Formula: see text] years. However, this value of [Formula: see text] is not universal. For example, the spectral density fluctuations of the atmospheric radiocarbon [Formula: see text]C are characterized by a Lorentzian with [Formula: see text] years. The frequency dependence of spectral density fluctuations for benthic [Formula: see text]O records contains two Lorentzians with [Formula: see text] years and [Formula: see text] years.
Doing peer review and receiving feedback: impact on scientific literacy and writing skills
Authors: Geithner Christina A. , Pollastro Alexandria N.
Published: February 2016

Doing peer review has been effectively implemented to help students develop critical reading and writing skills; however, its application in Human Physiology programs is limited. The purpose of the present study was to determine the impact of peer review on Human Physiology majors' perceptions of their scientific literacy and writing skills. Students enrolled in the Scientific Writing course completed multiple writing assignments, including three revisions after receiving peer and instructor feedback. Students self-assessed their knowledge, skills, and attitudes related to science and writing in pre- and postcourse surveys ( n = 26 with complete data). Seven survey items related to scientific literacy and writing skills impacted by peer review were selected for analysis. Scores on these survey items were summed to form a composite self-rating score. Responses to two questions regarding the most useful learning activities were submitted to frequency analysis. Mean postcourse scores for individual survey items and composite self-rating scores were significantly higher than precourse means ( P < 0.05). Peer review was the most frequently noted among 21 learning activities for increasing scientific literacy and in the top 5 for improving writing skills. In conclusion, peer review is an effective teaching/learning approach for improving undergraduate Human Physiology majors' knowledge, skills, and attitudes regarding science and scientific writing.
The XIIIth International Physiological Congress in Boston in 1929: American physiology comes of age
Authors: Rall Jack A.
Published: February 2016

In the 19th century, the concept of experimental physiology originated in France with Claude Bernard, evolved in Germany stimulated by the teaching of Carl Ludwig, and later spread to Britain and then to the United States. The goal was to develop a physicochemical understanding of physiological phenomena. The first International Physiological Congress occurred in 1889 in Switzerland with an emphasis on experimental demonstrations. The XIIIth Congress, the first to be held outside of Europe, took place in Boston, MA, in 1929. It was a watershed meeting and indicated that American physiology had come of age. Meticulously organized, it was the largest congress to date, with over 1,200 participants from more than 40 countries. Getting to the congress was a cultural adventure, especially for the 400 scientists and their families from over 20 European countries, who sailed for 10 days on the S.S. Minnekahda. Many of the great physiologists of the world were in attendance, including 22 scientists who were either or would become Nobel Laureates. There were hundreds of platform presentations and many experimental demonstrations. The meeting was not without controversy as a conflict, still not completely settled, arose over the discovery of ATP. After the meeting, hundreds of participants made a memorable trip to the Marine Biological Laboratory at Woods Hole, MA, which culminated in a “good old fashioned Cape Cod Clambake.” Although not as spectacular as the 1929 congress, the physiological congresses have continued with goals similar to those established more than a century ago.
Learning theories 101: application to everyday teaching and scholarship
Authors: Kay Denise , Kibble Jonathan
Published: February 2016

Shifts in educational research, in how scholarship in higher education is defined, and in how funding is appropriated suggest that educators within basic science fields can benefit from increased understanding of learning theory and how it applies to classroom practice. This article uses a mock curriculum design scenario as a framework for the introduction of five major learning theories. Foundational constructs and principles from each theory and how they apply to the proposed curriculum designs are described. A summative table that includes basic principles, constructs, and classroom applications as well as the role of the teacher and learner is also provided for each theory.
Treatment with intranasal iloprost reduces disease manifestations in a murine model of previously established COPD
Authors: Lammi Matthew R. , Ghonim Mohamed A. , Pyakurel Kusma , Naura Amarjit S , Ibba Salome V. , Davis Christian J. , Okpechi Samuel C. , Happel Kyle I. , deBoisblanc Bennett P. , Shellito Judd , Boulares A. Hamid
Published: February 2016

Pulmonary endothelial prostacyclin appears to be involved in the pathogenesis of chronic obstructive pulmonary disease (COPD). The effect of treatment with a prostacyclin analog in animal models of previously established COPD is unknown. We evaluated the short- and long-term effect of iloprost on inflammation and airway hyperresponsiveness (AHR) in a murine model of COPD. Nineteen mice were exposed to LPS/elastase, followed by either three doses of intranasal iloprost or saline. In the long-term treatment experiment, 18 mice were exposed to LPS/elastase and then received 6 wk of iloprost or were left untreated as controls. In the short-term experiment, iloprost did not change AHR but significantly reduced serum IL-5 and IFN-γ. Long-term treatment with iloprost for both 2 and 6 wk significantly improved AHR. After 6 wk of iloprost, there was a reduction in bronchoalveolar lavage (BALF) neutrophils, serum IL-1β (30.0 ± 9.2 vs. 64.8 ± 7.4 pg/ml, P = 0.045), IL-2 (36.5 ± 10.6 vs. 83.8 ± 0.4 pg/ml, P = 0.01), IL-10 (75.7 ± 9.3 vs. 96.5 ± 3.5 pg/ml, P = 0.02), and nitrite (15.1 ± 5.4 vs. 30.5 ± 10.7 μmol, P = 0.01). Smooth muscle actin (SMA) in the lung homogenate was also significantly reduced after iloprost treatment ( P = 0.02), and SMA thickness was reduced in the small and medium blood vessels after iloprost ( P < 0.001). In summary, short- and long-term treatment with intranasal iloprost significantly reduced systemic inflammation in an LPS/elastase COPD model. Long-term iloprost treatment also reduced AHR, serum nitrite, SMA, and BALF neutrophilia. These data encourage future investigations of prostanoid therapy as a novel treatment for COPD patients.
Regulation of myofibroblast differentiation by cardiac glycosides
Authors: La Jennifer , Reed Eleanor B. , Koltsova Svetlana , Akimova Olga , Hamanaka Robert B. , Mutlu Gökhan M. , Orlov Sergei N. , Dulin Nickolai O.
Published: February 2016

Myofibroblast differentiation is a key process in pathogenesis of fibrotic diseases. Cardiac glycosides (ouabain, digoxin) inhibit Na+-K+-ATPase, resulting in increased intracellular [Na+]-to-[K+] ratio in cells. Microarray analysis suggested that increased intracellular [Na+]/[K+] ratio may promote the expression of cyclooxygenase-2 (COX-2), a critical enzyme in the synthesis of prostaglandins. Given antifibrotic effects of prostaglandins through activation of protein kinase A (PKA), we examined if cardiac glycosides stimulate COX-2 expression in human lung fibroblasts and how they affect myofibroblast differentiation. Ouabain stimulated a profound COX-2 expression and a sustained PKA activation, which was blocked by COX-2 inhibitor or by COX-2 knockdown. Ouabain-induced COX-2 expression and PKA activation were abolished by the inhibitor of the Na+/Ca2+ exchanger, KB-R4943. Ouabain inhibited transforming growth factor-β (TGF-β)-induced Rho activation, stress fiber formation, serum response factor activation, and the expression of smooth muscle α-actin, collagen-1, and fibronectin. These effects were recapitulated by an increase in intracellular [Na+]/[K+] ratio through the treatment of cells with K+-free medium or with digoxin. Although inhibition of COX-2 or of the Na+/Ca2+ exchanger blocked ouabain-induced PKA activation, this failed to reverse the inhibition of TGF-β-induced Rho activation or myofibroblast differentiation by ouabain. Together, these data demonstrate that ouabain, through the increase in intracellular [Na+]/[K+] ratio, drives the induction of COX-2 expression and PKA activation, which is accompanied by a decreased Rho activation and myofibroblast differentiation in response to TGF-β. However, COX-2 expression and PKA activation are not sufficient for inhibition of the fibrotic effects of TGF-β by ouabain, suggesting that additional mechanisms must exist.
Electrophysiological characterization of voltage-dependent calcium currents and TRPV4 currents in human pulmonary fibroblasts
Authors: Rahman Mozibur , Mukherjee Subhendu , Sheng Wei , Nilius Bernd , Janssen Luke J.
Published: February 2016

We have presented indirect evidence of a key role for voltage-dependent Ca2+ currents in TGFβ-induced synthetic function in human pulmonary fibroblast (HPF), as well as in bleomycin-induced pulmonary fibrosis in mice. Others, however, have provided indirect evidence for transient receptor potential vanilloid 4 (TRPV4) channels in both of those effects. Unfortunately, definitive electrophysiological descriptions of both currents in HPFs have been entirely lacking. In this study, we provide the first direct electrophysiological and pharmacological evidence of the currents in HPFs at rest and during overnight stimulation with TGFβ. These currents include a Ca2+-dependent K+ current, a TRPV4 current, a chloride current, and an L-type voltage-dependent Ca2+ current. Evidence for the TRPV4 current include activation of a large-conductance change by two putatively TRPV4-selective agonists (4α-phorbol-12,13-didecanoate; GSK1016790A), with a reversal potential near 0 mV, partial sensitivity to two different TRPV4-selective blockers (RN1734; HC067047), and partial reduction following removal of external Na+. Substantial reduction of the evoked current was seen following the coapplication of RN1734, DIDS, and niflumic acid, suggesting that a chloride current is also involved. The voltage-dependent Ca2+ current is found to be “L-type” in nature, as indicated by the voltage and time dependence of its activation, deactivation, and inactivation properties, and by its pharmacology (sensitivity to replacement with barium and inhibition by nifedipine, verapamil, or mibefradil). We also found that overnight treatment with TGFβ evoked a periodic current (inward at negative holding potentials, with reversal potential near 0 mV), which is sufficient to trigger the voltage-dependent Ca2+ currents and, thereby, account for the rhythmic Ca2+ oscillations, which we have described previously in these cells.
A short period of high-intensity interval training improves skeletal muscle mitochondrial function and pulmonary oxygen uptake kinetics
Authors: Christensen Peter M. , Jacobs Robert A. , Bonne Thomas , Flück Daniela , Bangsbo Jens , Lundby Carsten
Published: February 2016

The aim of the present study was to examine whether improvements in pulmonary oxygen uptake (V̇o2) kinetics following a short period of high-intensity training (HIT) would be associated with improved skeletal muscle mitochondrial function. Ten untrained male volunteers (age 26 ± 2 yr; mean ± SD) performed six HIT sessions (8-12 × 60 s at incremental test peak power; 271 ± 52 W) over a 2-wk period. Before and after the HIT period, V̇o2kinetics was modeled during moderate-intensity cycling (110 ± 19 W). Mitochondrial function was assessed with high-resolution respirometry (HRR), and maximal activities of oxidative enzymes citrate synthase (CS) and cytochrome c oxidase (COX) were accordingly determined. In response to HIT, V̇o2kinetics became faster (τ: 20.4 ± 4.4 vs. 28.9 ± 6.1 s; P < 0.01) and fatty acid oxidation (ETFP) and leak respiration (LN) both became elevated ( P < 0.05). Activity of CS and COX did not increase in response to training. Both before and after the HIT period, fast V̇o2kinetics (low τ values) was associated with large values for ETFP, electron transport system capacity (ETS), and electron flow specific to complex II (CIIP) ( P < 0.05). Collectively, these findings support that selected measures of mitochondrial function obtained with HRR are important for fast V̇o2kinetics and better markers than maximal oxidative enzyme activity in describing the speed of the V̇o2response during moderate-intensity exercise.
Heat stress redistributes blood flow in arteries of the brain during dynamic exercise
Authors: Sato Kohei , Oue Anna , Yoneya Marina , Sadamoto Tomoko , Ogoh Shigehiko
Published: February 2016

We hypothesized that heat stress would decrease anterior and posterior cerebral blood flow (CBF) during exercise, and the reduction in anterior CBF would be partly associated with large increase in extracranial blood flow (BF). Nine subjects performed 40 min of semirecumbent cycling at 60% of the peak oxygen uptake in hot (35°C; Heat) and thermoneutral environments (25°C; Control). We evaluated BF and conductance (COND) in the external carotid artery (ECA), internal carotid artery (ICA), and vertebral artery (VA) using ultrasonography. During the Heat condition, ICA and VA BF were significantly increased 10 min after the start of exercise ( P < 0.05) and thereafter gradually decreased. ICA COND was significantly decreased ( P < 0.05), whereas VA COND remained unchanged throughout Heat. Compared with the Control, either BF or COND of ICA and VA at the end of Heat tended to be lower, but not significantly. In contrast, ECA BF and COND at the end of Heat were both higher than levels in the Control condition ( P < 0.01). During Heat, a reduction in ICA BF appears to be associated with a decline in end-tidal CO2 tension ( r = 0.84), whereas VA BF appears to be affected by a change in cardiac output ( r = 0.87). In addition, a change in ECA BF during Heat was negatively correlated with a change in ICA BF ( r = −0.75). Heat stress resulted in modification of the vascular response of head and brain arteries to exercise, which resulted in an alteration in the distribution of cardiac output. Moreover, a hyperthermia-induced increase in extracranial BF might compromise anterior CBF during exercise with heat stress.
Mechanisms of airway responses to esophageal acidification in cats
Authors: Lang Ivan M. , Haworth Steven T. , Medda Bidyut K. , Forster Hubert , Shaker Reza
Published: February 2016

Acid in the esophagus causes airway constriction, tracheobronchial mucous secretion, and a decrease in tracheal mucociliary transport rate. This study was designed to investigate the neuropharmacological mechanisms controlling these responses. In chloralose-anesthetized cats ( n = 72), we investigated the effects of vagotomy or atropine (100 μg·kg−1·30 min−1iv) on airway responses to esophageal infusion of 0.1 M PBS or 0.1 N HCl at 1 ml/min. We quantified 1) diameter of the bronchi, 2) tracheobronchial mucociliary transport rate, 3) tracheobronchial mucous secretion, and 4) mucous content of the tracheal epithelium and submucosa. We found that vagotomy or atropine blocked the airway constriction response but only atropine blocked the increase in mucous output and decrease in mucociliary transport rate caused by esophageal acidification. The mucous cells of the mucosa produced more Alcian blue- than periodic acid-Schiff (PAS)-stained mucosubstances, and the mucous cells of the submucosa produced more PAS- than Alcian blue-stained mucosubstances. Selective perfusion of the different segments of esophagus with HCl or PBS resulted in significantly greater production of PAS-stained mucus in the submucosa of the trachea adjacent to the HCl-perfused esophagus than in that adjacent to the PBS-perfused esophagus. In conclusion, airway constriction caused by esophageal acidification is mediated by a vagal cholinergic pathway, and the tracheobronchial transport response is mediated by cholinergic receptors. Acid perfusion of the esophagus selectively increases production of neutral mucosubstances of the apocrine glands by a local mechanism. We hypothesize that the airway responses to esophageal acid exposure are part of the innate, rather than acute emergency, airway defense system.