bluuebunny/crossref_metadata_2025 huggingface dataset:
Altered expression of an RBP‐associated arginine methyltransferase 7 in Leishmania major affects parasite infection
Authors: Ferreira Tiago R. , Alves‐Ferreira Eliza V. C. , Defina Tania P. A. , Walrad Pegine , Papadopoulou Barbara , Cruz Angela K.
Published: October 2014

Protein arginine methylation is a widely conserved post‐translational modification performed by arginine methyltransferases (PRMTs). However, its functional role in parasitic protozoa is still under‐explored. The Leishmania major genome encodes five PRMT homologs, including PRMT7. Here we show that LmjPRMT7 expression and arginine monomethylation are tightly regulated in a lifecycle stage‐dependent manner. LmjPRMT7 levels are higher during the early promastigote logarithmic phase, negligible at stationary and late‐stationary phases and rise once more post‐differentiation to intracellular amastigotes. Immunofluorescence and co‐immunoprecipitation studies demonstrate that LmjPRMT7 is a cytosolic protein associated with several RNA‐binding proteins (RBPs) from which Alba20 is monomethylated only in LmjPRMT7‐expressing promastigote stages. In addition, Alba20 protein levels are significantly altered in stationary promastigotes of the LmjPRMT7 knockout mutant. Considering RBPs are well‐known mammalian PRMT substrates, our data suggest that arginine methylation via LmjPRMT7 may modulate RBP function during Leishmania spp. lifecycle progression. Importantly, genomic deletion of the LmjPRMT7 gene leads to an increase in parasite infectivity both in vitro and in vivo, while lesion progression is significantly reduced in LmjPRMT7‐overexpressing parasites. This study is the first to describe a role of Leishmania protein arginine methylation in host–parasite interactions.
Spider mites suppress tomato defenses downstream of jasmonate and salicylate independently of hormonal crosstalk
Authors: Alba Juan M. , Schimmel Bernardus C. J. , Glas Joris J. , Ataide Livia M. S. , Pappas Maria L. , Villarroel Carlos A. , Schuurink Robert C. , Sabelis Maurice W. , Kant Merijn R.
Published: October 2014

Plants respond to herbivory by mounting a defense. Some plant‐eating spider mites (Tetranychus spp.) have adapted to plant defenses to maintain a high reproductive performance. From natural populations we selected three spider mite strains from two species, Tetranychus urticae and Tetranychus evansi, that can suppress plant defenses, using a fourth defense‐inducing strain as a benchmark, to assess to which extent these strains suppress defenses differently.

We characterized timing and magnitude of phytohormone accumulation and defense‐gene expression, and determined if mites that cannot suppress defenses benefit from sharing a leaf with suppressors.

The nonsuppressor strain induced a mixture of jasmonate‐ (JA) and salicylate (SA)‐dependent defenses. Induced defense genes separated into three groups: ‘early’ (expression peak at 1 d postinfestation (dpi)); ‘intermediate’ (4 dpi); and ‘late’, whose expression increased until the leaf died. The T. evansi strains suppressed genes from all three groups, but the T. urticae strain only suppressed the late ones. Suppression occurred downstream of JA and SA accumulation, independently of the JA–SA antagonism, and was powerful enough to boost the reproductive performance of nonsuppressors up to 45%.

Our results show that suppressing defenses not only brings benefits but, within herbivore communities, can also generate a considerable ecological cost when promoting the population growth of a competitor.
Host diversity affects the abundance of the extraradical arbuscular mycorrhizal network
Authors: Engelmoer Daniel J. P. , Kiers E. Toby
Published: October 2014

Arbuscular mycorrhizal fungi (AMF) can form complex networks in the soil that connect different host plants. Previous studies have focused on the effects of these networks on individual hosts and host communities. However, very little is known about how different host species affect the success of the fungal network itself.

Given the potentially strong selection pressure against hosts that invest in a fungal network which benefits their competitors, we predict that the presence of multiple host species negatively affects the growth of the extraradical network.

We designed an experiment using an in vitro culture approach to investigate the effect of different hosts (carrot, chichory and medicago) on the formation of a common mycelial network. In vitro root cultures, each inoculated with their own fungal network, were grown in a double split plate design with two host compartments and a common central compartment where fungal networks could form.

We found that the size of fungal networks differs depending on the social environment of the host. When host species were propagated in a mixed species environment, the fungal abundance was significantly reduced compared to monoculture predictions. Our work demonstrates how host‐to‐host conflict can influence the abundance of the fungal partner.
For the Rest of Asia, America Might Be a Friend, but China Cannot Be an Enemy
Authors: YEO GEORGE
Published: October 2014

In 1990, right after the Berlin Wall fell, NPQ published our Spring edition, titled “The New World Disorder,” about the nationalistic chaos and up‐in‐theair sensibility of that fraught new historical moment.

Nearly a quarter of a century later, the regime of globalization that had supplanted the Cold War world of blocs is itself coming apart at the seams. Even Henry Kissinger these days says “the world order is crumbling.”

Will this New World Disorder 2.0 revert to a system of conflicting blocs, as during the Cold War, or will we be mature enough to save the interdependence of plural identities that is the foundation of a new global civilization?

In this section our contributors offer their perspectives on what the future holds.
Will Erdogan's Victory Mark the Rise of Illiberal Democracy?
Authors: ALTINAY ALI HAKAN
Published: October 2014

In 1990, right after the Berlin Wall fell, NPQ published our Spring edition, titled “The New World Disorder,” about the nationalistic chaos and up‐in‐theair sensibility of that fraught new historical moment.

Nearly a quarter of a century later, the regime of globalization that had supplanted the Cold War world of blocs is itself coming apart at the seams. Even Henry Kissinger these days says “the world order is crumbling.”

Will this New World Disorder 2.0 revert to a system of conflicting blocs, as during the Cold War, or will we be mature enough to save the interdependence of plural identities that is the foundation of a new global civilization?

In this section our contributors offer their perspectives on what the future holds.
Electronic Interactions of Michler's Ketone with DNA Bases in Synthetic Hairpins
Authors: Jalilov Almaz S. , Young Ryan M. , Eaton Samuel W. , Wasielewski Michael R. , Lewis Frederick D.
Published: October 2014

The mechanism and dynamics of photoinduced electron transfer in two families of DNA hairpins possessing Michler's ketone linkers have been investigated by means of steady state and time‐resolved transient absorption and emission spectroscopies. The excited state behavior of the diol linker employed in hairpin synthesis is similar to that of Michler's ketone in methanol solution. Hairpins possessing only a Michler's ketone linker undergo fast singlet state charge separation and charge recombination with an adjacent purine base, attributed to well‐stacked ground state conformations, and intersystem crossing to the triplet state, attributed to poorly stacked ground state conformations. The failure of the triplet to undergo electron transfer reactions on the 7 ns time scale of our measurements is attributed to the low triplet energy and reduction potential of the twisted triplet state. Hairpins possessing both a Michler's ketone linker and a perylenediimide base surrogate separated by four base pairs undergo photoinduced hole transport from the diimide to Michler's ketone upon excitation of the diimide. The efficiency of hole transport is dependent upon the sequence of the intervening purine bases.
The type of competition modulates the ecophysiological response of grassland species to elevated CO2 and drought
Authors: Miranda‐Apodaca J. , Pérez‐López U. , Lacuesta M. , Mena‐Petite A. , Muñoz‐Rueda A.
Published: October 2014

The effects of elevated CO2 and drought on ecophysiological parameters in grassland species have been examined, but few studies have investigated the effect of competition on those parameters under climate change conditions. The objective of this study was to determine the effect of elevated CO2 and drought on the response of plant water relations, gas exchange, chlorophyll a fluorescence and aboveground biomass in four grassland species, as well as to assess whether the type of competition modulates that response. Elevated CO2 in well‐watered conditions increased aboveground biomass by augmenting CO2 assimilation. Drought reduced biomass by reducing CO2 assimilation rate via stomatal limitation and, when drought was more severe, also non‐stomatal limitation. When plants were grown under the combined conditions of elevated CO2 and drought, drought limitation observed under ambient CO2 was reduced, permitting higher CO2 assimilation and consequently reducing the observed decrease in aboveground biomass. The response to climate change was species‐specific and dependent on the type of competition. Thus, the response to elevated CO2 in well‐watered grasses was higher in monoculture than in mixture, while it was higher in mixture compared to monoculture for forbs. On the other hand, forbs were more affected than grasses by drought in monoculture, while in mixture the negative effect of drought was higher in grasses than in forbs, due to a lower capacity to acquire water and mineral nutrients. These differences in species‐level growth responses to CO2 and drought may lead to changes in the composition and biodiversity of the grassland plant community in future climate conditions.
Calm Temperament Improves Reproductive Performance of Beef Cows
Authors: Kasimanickam R , Asay M , Schroeder S , Kasimanickam V , Gay JM , Kastelic JP , Hall JB , Whittier WD
Published: October 2014

Contents

Profitability of a beef operation is determined by the proportion of cows attaining pregnancy early in the breeding season and those that are pregnant at the end of breeding season. Many factors, including temperament, contribute to those reproductive parameters. The objective of this study was to evaluate effects of temperament on reproductive performance of beef cows. In Experiment 1, Angus and Angus‐cross beef cows (n = 1546) from eight locations were assigned a body condition score (BCS; 1 = emaciated; 9 = obese) and chute exit and gait score (1 = slow exit, walk; calm temperament; 2 = jump, trot or run; excitable temperament). Cows were grouped with bulls (1 : 25 to 1 : 30; with satisfactory breeding potential and free of venereal disease) for an 85‐day breeding season. Pregnancy status and stage of gestation were determined (transrectal palpation) 35 days after the end of the breeding season. Controlling for BCS (p < 0.01) and handling facility (p < 0.0001) and handling facility by temperament score interaction (p < 0.001), breeding season pregnancy rate was lower in excited versus calm cows [88.6% (798/901) vs 94.1% (607/645); p < 0.001]. Cows with an excitable temperament took 24 more days to become pregnant compared to calm cows (median days to pregnancy, 35 vs 59 days; p < 0.0001). In Experiment 2, Angus and Angus‐cross beef cows (n = 1407) from 8 locations were assigned scores for body condition and chute exit and gait (as described in Experiment 1) and assigned to bulls (breeding sound and free of venereal disease; 1 : 25 to 1 : 30) for 85 days. Pregnancy status was determined by transrectal palpation at 2 and 6 months after the onset of the breeding season. Controlling for BCS (p < 0.05), pregnancy loss was higher in excited versus calm cows [5.5% (36/651) vs 3.2% (20/623), p < 0.0001]. In conclusion, beef cows with an excitable temperament had significantly lower reproductive performance than calmer cows. The modified two‐point chute exit–gait scoring method was repeatable and identified cattle with an excitable temperament.
Productivity Growth of the Nontradable Sectors in China
Authors: He Dong , Zhang Wenlang , Han Gaofeng , Wu Tommy
Published: October 2014

Little is known about the total factor productivity of the nontradable sectors in China. In this paper we estimate productivity growth of the nontradable sectors by studying the relative price movements of the nontradable sectors vis‐à‐vis the tradable sectors, i.e. changes in the internal real exchange rate. We find that prices of the nontradable sectors have risen significantly faster than those of the tradable sectors since China's accession to the WTO, and as a result China's internal real exchange rate has appreciated faster than the renminbi real effective exchange rate. We also find that the nontradable sectors have seen much lower productivity growth than the tradable sectors. We argue that it is important to raise China's productivity growth in the nontradable sectors through policy actions to achieve growth rebalancing and containing inflationary pressures in the medium run.
A J‐function for Inhomogeneous Spatio‐temporal Point Processes
Authors: Cronie O. , Van Lieshout M. N. M.
Published: October 2014

We propose a new summary statistic for inhomogeneous intensity‐reweighted moment stationarity spatio‐temporal point processes. The statistic is defined in terms of the n‐point correlation functions of the point process, and it generalizes the J‐function when stationarity is assumed. We show that our statistic can be represented in terms of the generating functional and that it is related to the spatio‐temporal K‐function. We further discuss its explicit form under some specific model assumptions and derive ratio‐unbiased estimators. We finally illustrate the use of our statistic in practice. © 2014 Board of the Foundation of the Scandinavian Journal of Statistics
Navigating the Road to College: Race and Class Variation in the College Application Process
Authors: Holland Megan M.
Published: October 2014

College attendance brings significant financial gain in lifetime earnings, and in order to reap those benefits more students are attending college than ever before. At the same time as more students have been applying to college, the application process itself has changed dramatically in the last few decades. As the last hurdle on the road to college, the application process is a critical step in the overall college‐choice process. However, until recently much of the research on college choice gave little attention to the actual steps of college application and did not always attend to variations by race and class. Considering the increasing importance of a college education and the consistent inequalities by race and class in who attends college, research examining how social background affects the ways in which students navigate the college application process is crucial. This review examines what we do know about race and class variation in college application, drawing from literature across sociology, economics, and higher education. This review addresses three questions: how does the admissions and application process affect race and class inequalities in college attendance? How have scholars modeled this process and do these models capture the experiences of students across race and class? And finally, how do students from different social backgrounds vary in their approach to applying to college?
Random blood glucose may be used to assess long‐term glycaemic control among patients with type 2 diabetes mellitus in a rural African clinical setting
Authors: Rasmussen Jon B. , Nordin Lovisa S. , Rasmussen Niclas S. , Thomsen Jakúp A. , Street Laura A. , Bygbjerg Ib C. , Christensen Dirk L.
Published: October 2014

Objectives

To investigate the diagnostic accuracy of random blood glucose (RBG) on good glycaemic control among patients with diabetes mellitus (DM) in a rural African setting.

Methods

Cross‐sectional study at St. Francis' Hospital in eastern Zambia. RBG and HbA1c were measured during one clinical review only. Other information obtained was age, sex, body mass index, waist circumference, blood pressure, urine albumin–creatinine ratio, duration since diagnosis and medication.

Results

One hundred and one patients with DM (type 1 DM = 23, type 2 DM = 78) were included. Spearman's rank correlation coefficient revealed a significant correlation between RBG and HbA1c among the patients with type 2 DM (r = 0.73, P < 0.001) but not patients with type 1 DM (r = 0.17, P = 0.44). Furthermore, in a multivariate linear regression model (R2 = 0.71) RBG (per mmol/l increment) (B = 0.28, 95% CI:0.24–0.32, P < 0.001) was significantly associated with HbA1c among the patients with type 2 DM. Based on ROC analysis (AUC = 0.80, SE = 0.05), RBG ≤7.5 mmol/l was determined as the optimal cut‐off value for good glycaemic control (HbA1c <7.0% [53 mmol/mol]) among patients with type 2 DM (sensitivity = 76.7%; specificity = 70.8%; positive predictive value = 62.2%; negative predictive value = 82.9%).

Conclusions

Random blood glucose could possibly be used to assess glycaemic control among patients with type 2 DM in rural settings of sub‐Saharan Africa.
Salinity tolerance in soybean is modulated by natural variation in GmSALT3
Authors: Guan Rongxia , Qu Yue , Guo Yong , Yu Lili , Liu Ying , Jiang Jinghan , Chen Jiangang , Ren Yulong , Liu Guangyu , Tian Lei , Jin Longguo , Liu Zhangxiong , Hong Huilong , Chang Ruzhen , Gilliham Matthew , Qiu Lijuan
Published: October 2014

The identification of genes that improve the salt tolerance of crops is essential for the effective utilization of saline soils for agriculture. Here, we use fine mapping in a soybean (Glycine max (L.) Merr.) population derived from the commercial cultivars Tiefeng 8 and 85–140 to identify GmSALT3 (salt tolerance‐associated gene on chromosome 3), a dominant gene associated with limiting the accumulation of sodium ions (Na+) in shoots and a substantial enhancement in salt tolerance in soybean. GmSALT3 encodes a protein from the cation/H+ exchanger family that we localized to the endoplasmic reticulum and which is preferentially expressed in the salt‐tolerant parent Tiefeng 8 within root cells associated with phloem and xylem. We identified in the salt‐sensitive parent, 85–140, a 3.78‐kb copia retrotransposon insertion in exon 3 of Gmsalt3 that truncates the transcript. By sequencing 31 soybean landraces and 22 wild soybean (Glycine soja) a total of nine haplotypes including two salt‐tolerant haplotypes and seven salt‐sensitive haplotypes were identified. By analysing the distribution of haplotypes among 172 Chinese soybean landraces and 57 wild soybean we found that haplotype 1 (H1, found in Tiefeng 8) was strongly associated with salt tolerance and is likely to be the ancestral allele. Alleles H2–H6, H8 and H9, which do not confer salinity tolerance, were acquired more recently. H1, unlike other alleles, has a wide geographical range including saline areas, which indicates it is maintained when required but its potent stress tolerance can be lost during natural selection and domestication. GmSALT3 is a gene associated with salt tolerance with great potential for soybean improvement.
N‐linked glycosylation of AtVSR1 is important for vacuolar protein sorting in Arabidopsis
Authors: Shen Jinbo , Ding Yu , Gao Caiji , Rojo Enrique , Jiang Liwen
Published: October 2014

Vacuolar sorting receptors (VSRs) in Arabidopsis mediate the sorting of soluble proteins to vacuoles in the secretory pathway. The VSRs are post‐translationally modified by the attachment of N‐glycans, but the functional significance of such a modification remains unknown. Here we have studied the role(s) of glycosylation in the stability, trafficking and vacuolar protein transport of AtVSR1 in Arabidopsis protoplasts. AtVSR1 harbors three complex‐type N‐glycans, which are located in the N‐terminal ‘PA domain’, the central region and the C‐terminal epidermal growth factor repeat domain, respectively. We have demonstrated that: (i) the N‐glycans do not affect the targeting of AtVSR1 to pre‐vacuolar compartments (PVCs) and its vacuolar degradation; and (ii) N‐glycosylation alters the binding affinity of AtVSR1 to cargo proteins and affects the transport of cargo into the vacuole. Hence, N‐glycosylation of AtVSR1 plays a critical role in its function as a VSR in plants.
Lactococcus garvieae Endocarditis on a Prosthetic Biological Aortic Valve
Authors: Tsur A. , Slutzki T. , Flusser D.
Published: October 2014

Lactococcus garvieae (LG) endocarditis is a rare disease in humans. There are only about 16 reported cases in the world. We report a 76‐year‐old male patient with LG endocarditis. In depth interview with the patient revealed that 2 weeks prior to admission, he had eaten sushi containing raw fish. Unlike many of the other infections reported, which were on a native mitral valve, our patient's vegetation was on a prosthetic aortic valve.
Thermal roll-to-roll imprinted nanogratings on plastic film
Authors: Unno Noriyuki , Mäkelä Tapio , Taniguchi Jun
Published: October 2014

Nanogratings can be used in various fields, such as optics, electronics, or energy conversion. In the next generation, the desired area of nanogratings will be in excess of 1 m2 and there is therefore a demand for an effective nanopatterning technique capable of fabricating future devices on this scale at low cost and in high volume. The roll-to-roll nanoimprint (R2RNIL) technique has received much attention because of its simplicity and high throughput. Thermal R2RNIL (T-R2RNIL), in particular, is expected to provide a major breakthrough because, for example, the costs of materials for the technique are much lower than those for ultraviolet R2RNIL, which requires a photocurable resin. Furthermore, T-R2RNIL is a dry process and is therefore more suited to industrial application. In T-R2RNIL with a nanograting mold, understanding the replication behavior, which varies with the process temperature, is a key to obtaining the required features. The authors examined T-R2RNIL high-speed patterning of nanogratings on a cellulose acetate film at various process temperatures and feature sizes of the mold. The replication behavior of a nanograting mold was found to differ from that of a micrograting mold. In addition, the depth of the imprinted pattern could be controlled by varying the process temperature and the pressure. This controllability permits the ready fabrication of nanogratings of various heights from a single mold.
A trans-dimensional polynomial-spline parameterization for gradient-based geoacoustic inversion
Authors: Steininger Gavin , Dosso Stan E. , Holland Charles W. , Dettmer Jan
Published: October 2014

This paper presents a polynomial spline-based parameterization for trans-dimensional geoacoustic inversion. The parameterization is demonstrated for both simulated and measured data and shown to be an effective method of representing sediment geoacoustic profiles dominated by gradients, as typically occur, for example, in muddy seabeds. Specifically, the spline parameterization is compared using the deviance information criterion (DIC) to the standard stack-of-homogeneous layers parameterization for the inversion of bottom-loss data measured at a muddy seabed experiment site on the Malta Plateau. The DIC is an information criterion that is well suited to trans-D Bayesian inversion and is introduced to geoacoustics in this paper. Inversion results for both parameterizations are in good agreement with measurements on a sediment core extracted at the site. However, the spline parameterization more accurately resolves the power-law like structure of the core density profile and provides smaller overall uncertainties in geoacoustic parameters. In addition, the spline parameterization is found to be more parsimonious, and hence preferred, according to the DIC. The trans-dimensional polynomial spline approach is general, and applicable to any inverse problem for gradient-based profiles. [Work supported by ONR.].
Tissue harmonic synthetic aperture ultrasound imaging
Authors: Hemmsen Martin Christian , Rasmussen Joachim Hee , Jensen Jørgen Arendt
Published: October 2014

Synthetic aperture sequential beamforming (SASB) and tissue harmonic imaging (THI) are combined to improve the image quality of medical ultrasound imaging. The technique is evaluated in a comparative study against dynamic receive focusing (DRF). The objective is to investigate if SASB combined with THI improves the image quality compared to DRF-THI. The major benefit of SASB is a reduced bandwidth between the probe and processing unit. A BK Medical 2202 Ultraview ultrasound scanner was used to acquire beamformed RF data for offline evaluation. The acquisition was made interleaved between methods, and data were recorded with and without pulse inversion for tissue harmonic imaging. Data were acquired using a Sound Technology 192 element convex array transducer from both a wire phantom and a tissue mimicking phantom to investigate spatial resolution and penetration. In vivo scans were also performed for a visual comparison. The spatial resolution for SASB-THI is on average 19% better than DRI-THI, and the investigation of penetration showed equally good signal-to-noise ratio. In vivo B-mode scans were made and compared. The comparison showed that SASB-THI reduces the artifact and noise interference and improves image contrast and spatial resolution.
High frequency components of ship noise in shallow water with a discussion of implications for harbor porpoises (Phocoena phocoena)
Authors: Hermannsen Line , Beedholm Kristian , Tougaard Jakob , Madsen Peter T.
Published: October 2014

Growing ship traffic worldwide has led to increased vessel noise with possible negative impacts on marine life. Most research has focused on low frequency components of ship noise, but for high-frequency specialists, such as the harbor porpoise (Phocoena phocoena), medium-to-high frequency noise components are likely more of a concern. To test for biologically relevant levels of medium-to-high frequency vessel noise, different types of Automatic Identification System located vessels were recorded using a broadband recording system in four heavily ship-trafficked marine habitats in Denmark. Vessel noise from a range of different ship types substantially elevated ambient noise levels across the entire recording band from 0.025 to 160 kHz at ranges between 60 and 1000 m. These ship noise levels are estimated to cause hearing range reduction of >20 dB (at 1 and 10 kHz) from ships passing at distances of 1190 m and >30 dB reduction (at 125 kHz) from ships at distances of 490 m or less. It is concluded that a diverse range of vessels produce substantial noise at high frequencies, where toothed whale hearing is most sensitive, and that vessel noise should be considered over a broad frequency range, when assessing noise effects on porpoises and other small toothed whales.
Personal audio with a planar bright zone
Authors: Coleman Philip , Jackson Philip J. B. , Olik Marek , Abildgaard Pedersen Jan
Published: October 2014

Reproduction of multiple sound zones, in which personal audio programs may be consumed without the need for headphones, is an active topic in acoustical signal processing. Many approaches to sound zone reproduction do not consider control of the bright zone phase, which may lead to self-cancellation problems if the loudspeakers surround the zones. Conversely, control of the phase in a least-squares sense comes at a cost of decreased level difference between the zones and frequency range of cancellation. Single-zone approaches have considered plane wave reproduction by focusing the sound energy in to a point in the wavenumber domain. In this article, a planar bright zone is reproduced via planarity control, which constrains the bright zone energy to impinge from a narrow range of angles via projection in to a spatial domain. Simulation results using a circular array surrounding two zones show the method to produce superior contrast to the least-squares approach, and superior planarity to the contrast maximization approach. Practical performance measurements obtained in an acoustically treated room verify the conclusions drawn under free-field conditions.
Infrasonic attenuation in the upper mesosphere–lower thermosphere: A comparison between Navier–Stokes and Burnett predictions
Authors: Akintunde Akinjide , Petculescu Andi
Published: October 2014

This paper presents the results of a pilot study comparing the use of continuum and non-continuum fluid dynamics to predict infrasound attenuation in the rarefied lower thermosphere. The continuum approach is embodied by the Navier–Stokes equations, while the non-continuum method is implemented via the Burnett equations [Proc. London Math. Soc. 39, 385–430 (1935); 40, 382–435 (1936)]. In the Burnett framework, the coupling between stress tensor and heat flux affects the dispersion equation, leading to an attenuation coefficient smaller than its Navier–Stokes counterpart by amounts of order 0.1 dB/km at 0.1 Hz, 10 dB/km at 1 Hz, and 100 dB/km at 10 Hz. It has been observed that many measured thermospheric arrivals are stronger than current predictions based on continuum mechanics. In this context, the consistently smaller Burnett-based absorption is cautiously encouraging.
Effective viscosity in a wave propagation model for ultrasonic particle sizing in non-dilute suspensions
Authors: Al-Lashi Raied S. , Challis Richard E.
Published: October 2014

Estimates of particle size distributions (PSDs) in solid-in-liquid suspensions can be obtained from measurements of ultrasonic wave attenuation. The technique is based on adaptively fitting theoretical wave propagation models to the measured data across a frequency range. These models break down at high solid concentrations and it is believed that this failure is due to the effective viscosity of the mixture in the vicinity of the particles being different from that of the continuous phase. This paper discusses PSD estimation when a number of different viscosity formulations are incorporated into the wave propagation model. The viscosity model due to Happel provides the best estimate of PSD in suspensions of medium concentration.
Tunable cylindrical shell as an element in acoustic metamaterial
Authors: Titovich Alexey S. , Norris Andrew N.
Published: October 2014

Elastic cylindrical shells are fitted with an internal mechanism which is optimized so that, in the quasi-static regime, the combined system exhibits prescribed effective acoustic properties. The mechanism consists of a central mass supported by an axisymmetric distribution of elastic stiffeners. By appropriate selection of the mass and stiffness of the internal mechanism, the shell's effective acoustic properties (bulk modulus and density) can be tuned as desired. Subsonic flexural waves excited in the shell by the attachment of stiffeners are suppressed by including a sufficiently large number of such stiffeners. The effectiveness of the proposed metamaterial is demonstrated by matching the properties of a thin aluminum shell with a polymer insert to those of water. The scattering cross section in water is nearly zero over a broad range of frequencies at the lower end of the spectrum. By arranging the tuned shells in an array the resulting acoustic metamaterial is capable of steering waves. As an example, a cylindrical-to-plane wave lens is designed by varying the bulk modulus in the array according to the conformal mapping of a unit circle to a square.
Computational modeling of photoacoustic signals from mixtures of melanoma and red blood cells
Authors: Saha Ratan K.
Published: October 2014

A theoretical approach to model photoacoustic (PA) signals from mixtures of melanoma cells (MCs) and red blood cells (RBCs) is discussed. The PA signal from a cell approximated as a fluid sphere was evaluated using a frequency domain method. The tiny signals from individual cells were summed up obtaining the resultant PA signal. The local signal to noise ratio for a MC was about 5.32 and 5.40 for 639 and 822 nm illuminations, respectively. The PA amplitude exhibited a monotonic rise with increasing number of MCs for each incident radiation. The power spectral lines also demonstrated similar variations over a large frequency range (5–200 MHz). For instance, spectral intensity was observed to be 5.5 and 4.0 dB greater at 7.5 MHz for a diseased sample containing 1 MC and 22 952 RBCs than a normal sample composed of 22 958 RBCs at those irradiations, respectively. The envelope histograms generated from PA signals for mixtures of small numbers of MCs and large numbers of RBCs seemed to obey pre-Rayleigh statistics. The generalized gamma distribution found to facilitate better fits to the histograms than the Rayleigh and Nakagami distributions. The model provides a means to study PAs from mixtures of different populations of absorbers.
Developmental acoustic study of American English diphthongs
Authors: Lee Sungbok , Potamianos Alexandros , Narayanan Shrikanth
Published: October 2014

Developmental trends of durational and spectral parameters of five American English diphthongs are investigated by age and gender. Specifically, diphthong durations, the fundamental frequency (F0), and the first three formant (F1, F2, F3) trajectories as well as formant transition rates are analyzed as a function of age, gender and diphthong type. In addition, the distance between diphthong onset and offset positions and those of nearby monophthongs in the formant space is computed and age-dependent trends are presented. Furthermore, a spectral transition mid-point is estimated for a given diphthong trajectory and normalized time durations from onsets to mid-points are analyzed as a function of age and diphthong type. Finally, diphthong classification results using formant-related parameters are reported. Results show the expected age-dependent reductions of diphthong duration, fundamental frequency, onset and offset formant values, and formant transition rate. More interestingly, it is evident that speakers adjust onset and offset positions of diphthongs with respect to monophthongs as a function of age. Normalized duration of the first demisyllable segment is found to be different among diphthongs and that younger children spend more time in the first segment. The implications for diphthong development and the onset-offset definition of diphthongs are discussed in detail.
Robust high-order superdirectivity of circular sensor arrays
Authors: Wang Yong , Yang Yixin , Ma Yuanliang , He Zhengyao
Published: October 2014

This paper presents a detailed study of the high-order superdirectivity of circular sensor arrays, which is aimed at completing the authors' recently proposed analytical superdirectivity model. From the limit expression of the maximum directivity factor, it is shown that the circular arrays possess good potential for directivity improvement. It is found that the sensitivity function used as a robustness measurement can also be accurately decomposed into a series of closed-form sensitivity functions of eigenbeams, similar to the optimal beampattern and its corresponding directivity factor. Moreover, the performance of eigenbeams can be regarded as an indicator of error sensitivity, and the robustness constraint parameters can be estimated easily. Two specific approaches are proposed for obtaining robust superdirectivity on the basis of robustness analyses, and their performance is demonstrated experimentally.
Benefits of preserving stationary and time-varying formant structure in alternative representations of speech: Implications for cochlear implants
Authors: Nittrouer Susan , Lowenstein Joanna H. , Wucinich Taylor , Tarr Eric
Published: October 2014

Cochlear implants have improved speech recognition for deaf individuals, but further modifications are required before performance will match that of normal-hearing listeners. In this study, the hypotheses were tested that (1) implant processing would benefit from efforts to preserve the structure of the low-frequency formants and (2) time-varying aspects of that structure would be especially beneficial. Using noise-vocoded and sine-wave stimuli with normal-hearing listeners, two experiments examined placing boundaries between static spectral channels to optimize representation of the first two formants and preserving time-varying formant structure. Another hypothesis tested in this study was that children might benefit more than adults from strategies that preserve formant structure, especially time-varying structure. Sixty listeners provided data to each experiment: 20 adults and 20 children at each of 5 and 7 years old. Materials were consonant-vowel-consonant words, four-word syntactically correct, meaningless sentences, and five-word syntactically correct, meaningful sentences. Results showed that listeners of all ages benefited from having channel boundaries placed to optimize information about the first two formants, and benefited even more from having time-varying structure. Children showed greater gains than adults only for time-varying formant structure. Results suggest that efforts would be well spent trying to design processing strategies that preserve formant structure.
A neural interface provides long-term stable natural touch perception
Authors: Tan Daniel W. , Schiefer Matthew A. , Keith Michael W. , Anderson James Robert , Tyler Joyce , Tyler Dustin J.
Published: October 2014

Electrical stimulation, using patterned intensity, applied through cuff-type peripheral nerve interfaces provided stable touch perceptions in the fingers, thumb, and hand of two subjects with upper limb loss for 16 to 24 months.
Bionic Limbs: Clinical Reality and Academic Promises
Authors: Farina Dario , Aszmann Oskar
Published: October 2014

Several new neuroprosthetic systems provide sensation via direct nerve stimulation, constituting an important step forward in achieving sensory-motor integration and embodiment of bionic limbs (Tan
et al
. and Ortiz-Catalan
et al
., this issue; Raspopovic
et al
., 5 Feb 2014 issue, 222ra19).
Selection of a Multidrug Resistance Plasmid by Sublethal Levels of Antibiotics and Heavy Metals
Authors: Gullberg Erik , Albrecht Lisa M. , Karlsson Christoffer , Sandegren Linus , Andersson Dan I.
Published: October 2014

How sublethal levels of antibiotics and heavy metals select for clinically important multidrug resistance plasmids is largely unknown. Carriage of plasmids generally confers substantial fitness costs, implying that for the plasmid-carrying bacteria to be maintained in the population, the plasmid cost needs to be balanced by a selective pressure conferred by, for example, antibiotics or heavy metals. We studied the effects of low levels of antibiotics and heavy metals on the selective maintenance of a 220-kbp extended-spectrum β-lactamase (ESBL) plasmid identified in a hospital outbreak of
Klebsiella pneumoniae
and
Escherichia coli
. The concentrations of antibiotics and heavy metals required to maintain plasmid-carrying bacteria, the minimal selective concentrations (MSCs), were in all cases below (almost up to 140-fold) the MIC of the plasmid-free susceptible bacteria. This finding indicates that the very low antibiotic and heavy metal levels found in polluted environments and in treated humans and animals might be sufficiently high to maintain multiresistance plasmids. When resistance genes were moved from the plasmid to the chromosome, the MSC decreased, showing that MSC for a specific resistance conditionally depends on genetic context. This finding suggests that a cost-free resistance could be maintained in a population by an infinitesimally low concentration of antibiotic. By studying the effect of combinations of several compounds, it was observed that for certain combinations of drugs each new compound added lowered the minimal selective concentration of the others. This combination effect could be a significant factor in the selection of multidrug resistance plasmids/bacterial clones in complex multidrug environments.

IMPORTANCE
Antibiotic resistance is in many pathogenic bacteria caused by genes that are carried on large conjugative plasmids. These plasmids typically contain multiple antibiotic resistance genes as well as genes that confer resistance to biocides and heavy metals. In this report, we show that very low concentrations of single antibiotics and heavy metals or combinations of compounds can select for a large plasmid that carries resistance to aminoglycosides, β-lactams, tetracycline, macrolides, trimethoprim, sulfonamide, silver, copper, and arsenic. Our findings suggest that the low levels of antibiotics and heavy metals present in polluted external environments and in treated animals and humans could allow for selection and enrichment of bacteria with multiresistance plasmids and thereby contribute to the emergence, maintenance, and transmission of antibiotic-resistant disease-causing bacteria.
A rare cause of Cushing's syndrome: an ACTH-secreting phaeochromocytoma
Authors: Folkestad Lars , Andersen Marianne Skovsager , Nielsen Anne Lerberg , Glintborg Dorte
Published: October 2014

Excess glucocorticoid levels cause Cushing's syndrome (CS) and may be due to pituitary, adrenal or ectopic tumours. Adrenocorticotropic hormone (ACTH) levels are useful in identifying adrenal tumours. In rare cases, ACTH-producing phaeochromocytomas are the cause of CS. We present two cases of ACTH-secreting phaeochromocytoma as the underlying cause of CS. In both cases, female patients presented with the classical clinical signs of CS and an adrenal mass. High ACTH levels raised the suspicion of an ACTH-secreting phaeochromocytoma. The diagnosis was confirmed by urinary catecholamine levels and positive fluorine-18-L-dihydroxyphenylalanine (18F-DOPA) positron emission tomography (PET) CT (Case 1) and fluorodeoxyglucose PET-CT (Case 2). Both patients were treated with an α-blocker prior to surgical intervention. The two cases underline the importance of thorough diagnostic workup in patients with CS. An ACTH-secreting phaeochromocytoma should be checked for in patients with an adrenal mass and elevated ACTH levels.
Injuries in men's international ice hockey: a 7-year study of the International Ice Hockey Federation Adult World Championship Tournaments and Olympic Winter Games
Authors: Tuominen Markku , Stuart Michael J , Aubry Mark , Kannus Pekka , Parkkari Jari
Published: October 2014

Background

Information on ice hockey injuries at the international level is very limited. The aim of the study was to analyse the incidence, type, mechanism and severity of ice hockey injuries in men's international ice hockey tournaments.

Methods

All the injuries in men's International Ice Hockey Federation World Championship tournaments over a 7-year period were analysed using a strict definition of injury, standardised reporting strategies and an injury diagnosis made by a team physician.

Results

528 injuries were recorded in games resulting in an injury rate of 14.2 per 1000 player-games (52.1/1000 player-game hours). Additionally, 27 injuries occurred during practice. For WC A-pool Tournaments and Olympic Winter Games (OWG) the injury rate was 16.3/1000 player-games (59.6/1000 player-game hours). Body checking, and stick and puck contact caused 60.7% of the injuries. The most common types of injuries were lacerations, sprains, contusions and fractures. A laceration was the most common facial injury and was typically caused by a stick. The knee was the most frequently injured part of the lower body and the shoulder was the most common site of an upper body injury. Arenas with flexible boards and glass reduced the risk of injury by 29% (IRR 0.71, (95% CI 0.56 to 0.91)).

Conclusions

The incidence of injury during international ice hockey competition is relatively high. Arena characteristics, such as flexible boards and glass, appeared to reduce the risk of injury.
Age at diagnosis predicts deterioration in glycaemic control among children and adolescents with type 1 diabetes
Authors: Clements Mark A , Lind Marcus , Raman Sripriya , Patton Susana R , Lipska Kasia J , Fridlington Amanda G , Tang Fengming , Jones Phil G , Wu Yue , Spertus John A , Kosiborod Mikhail
Published: October 2014

Background

Poor glycemic control early in the course of type 1 diabetes mellitus (T1DM) increases the risk for microvascular complications. However, predictors of deteriorating control after diagnosis have not been described, making it difficult to identify high-risk patients and proactively provide aggressive interventions.

Objective

We examined whether diagnostic age, gender, and race were associated with deteriorating glycemic control during the first 5 years after diagnosis.

Participants

2218 pediatric patients with T1DM.

Methods

We conducted a longitudinal cohort study of pediatric patients with T1DM from the Midwest USA, 1993–2009, evaluating within-patient glycated hemoglobin (HbA1c) trajectories constructed from all available HbA1c values within 5 years of diagnosis.

Results

52.6% of patients were male; 86.1% were non-Hispanic Caucasian. The mean diagnostic age was 9.0±4.1 years. The mean number of HbA1c values/year/participant was 2.4±0.9. HbA1c trajectories differed markedly across age groups, with older patients experiencing greater deterioration than their younger counterparts (p<0.001). HbA1c trajectories, stratified by age, varied markedly by race (p for race×diagnostic age <0.001). Non-Hispanic African-American patients experienced higher initial HbA1c (8.7% vs 7.6% (71.6 vs 59.6 mmol/mol); p<0.001), and greater deterioration in HbA1c than non-Hispanic Caucasian patients across diagnostic ages (rise of 2.04% vs 0.99% per year (22.3 vs 10.8 mmol/mol/year); p<0.0001).

Conclusions

Older diagnostic age and black race are major risk factors for deterioration in glycemic control early in the course of T1DM. These findings can inform efforts to explore the reasons behind these differences and develop preventive interventions for high-risk patients.
A comparison of adverse event and fracture efficacy data for strontium ranelate in regulatory documents and the publication record
Authors: Bolland Mark J , Grey Andrew
Published: October 2014

Objective

Recently, the European Medicines Agency reported that strontium ranelate increases myocardial infarction risk in postmenopausal women, 8.5 years after it was registered for use in osteoporosis. Unreported serious adverse events in clinical trials for other pharmaceuticals have been described in recent years. We assessed reporting of adverse events and fracture efficacy of strontium.

Methods

We compared data on adverse effects (myocardial infarction, venous thromboembolism and pulmonary embolism) and fracture efficacy of strontium in publicly available regulatory documents with data in publications retrieved from searching PubMed.

Results

We identified 5 regulatory documents and 9 primary publications of 7 randomised, placebo-controlled trials of strontium that reported relevant data. We identified several areas of concern in these reports: the increased risk of myocardial infarction with strontium was not identified in a pivotal phase 3 clinical trial despite specific regulatory review of cardiovascular events; data on myocardial infarction were not included in any primary publication; increased risks of venous thromboembolism and pulmonary embolism with strontium were not reported in either of the phase 3 clinical trials; data on venous thromboembolism were reported in only 5 of 9 primary publications, data on pulmonary embolism in only 2 of 9 primary publications, and either was discussed in <50% of subsequent review articles. There were differences in participant numbers, fracture cases and venous thromboembolism cases between regulatory documents and primary publications. Based on all available data from primary publications and regulatory documents, the number of fractures prevented by strontium use is similar to the number of extra cases of venous thromboembolism, pulmonary embolism and myocardial infarction caused by strontium use.

Conclusions

The risks of strontium use are similar to the benefits. Full disclosure of the clinical trial data and regulatory documents would allow clinicians and their patients to decide whether use of the drug is worthwhile.