bluuebunny/crossref_metadata_2025 huggingface dataset:
A numerical study of droplet trapping in microfluidic devices
Authors: Nagel Mathias , Brun P.-T. , Gallaire François
Published: March 2014

Microfluidic channels are powerful means of control of minute volumes such as droplets. These droplets are usually conveyed at will in an externally imposed flow which follows the geometry of the micro-channel. It has recently been pointed out by Dangla et al. [“Trapping microfluidic drops in wells of surface energy,” Phys. Rev. Lett. 107(12), 124501 (2011)] that the motion of transported droplets may also be stopped in the flow, when they are anchored to grooves which are etched in the channels top wall. This feature of the channel geometry explores a direction that is usually uniform in microfluidics. Herein, this anchoring effect exploiting the three spatial directions is studied combining a depth averaged fluid description and a geometrical model that accounts for the shape of the droplet in the anchor. First, the presented method is shown to enable the capture and release droplets in numerical simulations. Second, this tool is used in a numerical investigation of the physical mechanisms at play in the capture of the droplet: a localized reduced Laplace pressure jump is found on its interface when the droplet penetrates the groove. This modified boundary condition helps the droplet cope with the linear pressure drop in the surrounding fluid. Held on the anchor the droplet deforms and stretches in the flow. The combination of these ingredients leads to recover the scaling law for the critical capillary number at which the droplets exit the anchors $\mathcal {C} a^{\star} \propto h^{2}/R^{2}$Ca★∝h2/R2 where h is the channel height and R the droplet undeformed radius.
Two dimensional symmetric correlation functions of the ${\rm \hat S}$Ŝ operator and two dimensional Fourier transforms: Considering the line coupling for P and R lines of linear molecules
Authors: Ma Q. , Boulet C. , Tipping R. H.
Published: March 2014

The refinement of the Robert-Bonamy (RB) formalism by considering the line coupling for isotropic Raman Q lines of linear molecules developed in our previous study [Q. Ma, C. Boulet, and R. H. Tipping, J. Chem. Phys. 139, 034305 (2013)] has been extended to infrared P and R lines. In these calculations, the main task is to derive diagonal and off-diagonal matrix elements of the Liouville operator iS1 − S2 introduced in the formalism. When one considers the line coupling for isotropic Raman Q lines where their initial and final rotational quantum numbers are identical, the derivations of off-diagonal elements do not require extra correlation functions of the ${\rm \hat S}$Ŝ operator and their Fourier transforms except for those used in deriving diagonal elements. In contrast, the derivations for infrared P and R lines become more difficult because they require a lot of new correlation functions and their Fourier transforms. By introducing two dimensional correlation functions labeled by two tensor ranks and making variable changes to become even functions, the derivations only require the latters’ two dimensional Fourier transforms evaluated at two modulation frequencies characterizing the averaged energy gap and the frequency detuning between the two coupled transitions. With the coordinate representation, it is easy to accurately derive these two dimensional correlation functions. Meanwhile, by using the sampling theory one is able to effectively evaluate their two dimensional Fourier transforms. Thus, the obstacles in considering the line coupling for P and R lines have been overcome. Numerical calculations have been carried out for the half-widths of both the isotropic Raman Q lines and the infrared P and R lines of C2H2 broadened by N2. In comparison with values derived from the RB formalism, new calculated values are significantly reduced and become closer to measurements.
Complex quantum Hamilton-Jacobi equation with Bohmian trajectories: Application to the photodissociation dynamics of NOCl
Authors: Chou Chia-Chun
Published: March 2014

The complex quantum Hamilton-Jacobi equation-Bohmian trajectories (CQHJE-BT) method is introduced as a synthetic trajectory method for integrating the complex quantum Hamilton-Jacobi equation for the complex action function by propagating an ensemble of real-valued correlated Bohmian trajectories. Substituting the wave function expressed in exponential form in terms of the complex action into the time-dependent Schrödinger equation yields the complex quantum Hamilton-Jacobi equation. We transform this equation into the arbitrary Lagrangian-Eulerian version with the grid velocity matching the flow velocity of the probability fluid. The resulting equation describing the rate of change in the complex action transported along Bohmian trajectories is simultaneously integrated with the guidance equation for Bohmian trajectories, and the time-dependent wave function is readily synthesized. The spatial derivatives of the complex action required for the integration scheme are obtained by solving one moving least squares matrix equation. In addition, the method is applied to the photodissociation of NOCl. The photodissociation dynamics of NOCl can be accurately described by propagating a small ensemble of trajectories. This study demonstrates that the CQHJE-BT method combines the considerable advantages of both the real and the complex quantum trajectory methods previously developed for wave packet dynamics.
Application of AXUV diode detectors at ASDEX Upgrade
Authors: Bernert M. , Eich T. , Burckhart A. , Fuchs J. C. , Giannone L. , Kallenbach A. , McDermott R. M. , Sieglin B. ,   ASDEX Upgrade Team
Published: March 2014

In the ASDEX Upgrade tokamak, a radiation measurement for a wide spectral range, based on semiconductor detectors, with 256 lines of sight and a time resolution of 5μs was recently installed. In combination with the foil based bolometry, it is now possible to estimate the absolutely calibrated radiated power of the plasma on fast timescales. This work introduces this diagnostic based on AXUV (Absolute eXtended UltraViolet) n-on-p diodes made by International Radiation Detectors, Inc. The measurement and the degradation of the diodes in a tokamak environment is shown. Even though the AXUV diodes are developed to have a constant sensitivity for all photon energies (1 eV-8 keV), degradation leads to a photon energy dependence of the sensitivity. The foil bolometry, which is restricted to a time resolution of less than 1 kHz, offers a basis for a time dependent calibration of the diodes. The measurements of the quasi-calibrated diodes are compared with the foil bolometry and found to be accurate on the kHz time scale. Therefore, it is assumed, that the corrected values are also valid for the highest time resolution (200 kHz). With this improved diagnostic setup, the radiation induced by edge localized modes is analyzed on fast timescales.
Experimental tests of free-volume tracer diffusion in water and other solvents
Authors: Spiegel Daniel R. , Kollie Paulses C. , Van Tilburg Scott J.
Published: March 2014

Using forced Rayleigh scattering, the tracer diffusion of methyl red through water and eight other solvents at different temperatures is investigated and the results are compared to the Cohen-Turnbull theory of free-volume diffusion. In seven solvents the effective non-Arrhenius activation energy measured experimentally agrees with the Cohen-Turnbull energy. In water, however, the diffusion can be described mathematically by the free volume model but there is a disagreement of more than an order of magnitude between these energies. We propose that the unique “zero point” free volume forced onto water by the strong hydrogen bonding requires a different mechanism for tracer motion.
Broadband polarization-insensitive absorber based on gradient structure metamaterial
Authors: Yang Guo-Hui , Liu Xiao-Xin , Lv Yue-Long , Fu Jia-Hui , Wu Qun , Gu Xuemai
Published: March 2014

Metamaterial absorber (MA) is a hot spot in the research on electromagnetic absorbers. In this paper, a metamaterial based broadband polarization-insensitive absorber is proposed. The absorber is fabricated with FR-4 dielectric substrate foiled with copper. The top layer of the unit cell of the MA is composed of resistors mounted crosswire and gradient split ring resonator (SRR) with a square metal patch (SMP) in it. The overall structure is symmetrical, which makes the MA polarization-insensitive. The gradient SRRs and SMPs resonate at adjacent frequencies resulting in broadband property. The absorption rates of the MA for TE and TM wave are calculated through the simulated S-parameters. The bandwidth is 9.9 GHz, where the absorption rate maintains 60% up to 98.28% in both cases and the relative bandwidth is 57.13%. Both broadband and polarization-insensitivity properties are achieved, which demonstrate promising application prospect of the proposed MA in shielding and stealth technology.
Frequency multiplexing for readout of spin qubits
Authors: Hornibrook J. M. , Colless J. I. , Mahoney A. C. , Croot X. G. , Blanvillain S. , Lu H. , Gossard A. C. , Reilly D. J.
Published: March 2014

We demonstrate a low loss, chip-level frequency multiplexing scheme for readout of scaled-up spin qubit devices. By integrating separate bias tees and resonator circuits on-chip for each readout channel, we realise dispersive gate-sensing in combination with charge detection based on two radio frequency quantum point contacts. We apply this approach to perform multiplexed readout of a double quantum dot in the few-electron regime and further demonstrate operation of a 10-channel multiplexing device. Limitations for scaling spin qubit readout to large numbers of multiplexed channels are discussed.
Neutron diffraction studies and magnetism in Ti doped SrFeO3−δ systems
Authors: Sendil Kumar A. , Babu P. D. , Srinath S.
Published: March 2014

The magnetic ground state of single phase tetragonal crystal structure with I4/mmm space group SrFe1−xTixO3−δ (x = 0.2 and 0.3) is investigated from 2 K to 300 K. Strong irreversibility is observed in zero-field-cooled (ZFC) and field-cooled DC magnetization curves. Arrott plots show the absence of spontaneous magnetization (MS) down to 2 K, ruling out the possibility of long range ferromagnetic order. Neutron diffraction measurements carried out at H = 0, 7 T (field cooled) at several temperatures above and below the T* (temperature at which MZFC(T) is maximum) do not show any additional peaks and also no difference in intensity rules out, both the long range antiferromagnetic and ferromagnetic orders. Hence, the combined study of dc magnetization and neutron diffraction results reveals cluster spin glass behavior in SrFe1−xTixO3−δ (x = 0.2 and 0.3).
Viscosity of interfacial water regulates ice nucleation
Authors: Li Kaiyong , Xu Shun , Chen Jing , Zhang Qiaolan , Zhang Yifan , Cui Dapeng , Zhou Xin , Wang Jianjun , Song Yanlin
Published: March 2014

Ice formation on solid surfaces is an important phenomenon in many fields, such as cloud formation and atmospheric icing, and a key factor for applications in preventing freezing. Here, we report temperature-dependent nucleation rates of ice for hydrophilic and hydrophobic surfaces. The results show that hydrophilic surface presents a lower ice nucleation rate. We develop a strategy to extract the thermodynamic parameters, J0 and Γ, in the context of classical nucleation theory. From the extracted J0 and Γ, we reveal the dominant role played by interfacial water. The results provide an insight into freezing mechanism on solid surfaces.
Stable amorphous In2O3-based thin-film transistors by incorporating SiO2 to suppress oxygen vacancies
Authors: Mitoma Nobuhiko , Aikawa Shinya , Gao Xu , Kizu Takio , Shimizu Maki , Lin Meng-Fang , Nabatame Toshihide , Tsukagoshi Kazuhito
Published: March 2014

Incorporating SiO2 into amorphous In2O3-based thin films is found to suppress the formation of unstable oxygen vacancies. The SiO2 incorporated thin film transistors exhibited reliable device characteristics after being annealed at 250 °C. Increasing the SiO2 content of the sputtering target decreased the sensitivity of the subthreshold swing and turn-on voltage of the device to the sputtering conditions used to deposit the amorphous oxide, making them more stable against electrical and thermal stresses. The increased activation energy of the charge carriers in the current off region indicated a smaller density of states at the conduction-band tail, supporting stable transistor operations.
Electric field-induced polarization rotation and ultrahigh piezoelectricity in PbTiO3
Authors: Ma Wenhui , Hao Aize
Published: March 2014

Polarization rotation, phase changes, and piezoelectric property of PbTiO3 under high electric field have been investigated using a Landau-Ginzburg-Devonshire phenomenological approach. Electric field versus temperature phase diagram has been constructed. Tetragonal (T)-monoclinic (MA)-rhombohedral (R) phase transition occurs when electric field is applied along pseudo-cubic [111] axis, and piezoelectric coefficient d33 is remarkably enhanced near the critical electric field for MA-R transition. With electric field applied along pseudo-cubic [011] axis, the polarization rotation involves the other two monoclinic phases (MB and MC), and ultrahigh d33 over 8000 pC/N has been found at the monoclinic-orthorhombic (M-O) transition region. The critical field for M-O transition (∼1000 MV/m) can be greatly lowered under hydrostatic pressure. Based on the reported strain gradient induced polarization rotation in epitaxial film, flexoelectric coefficient μ12 of PbTiO3 is estimated to be ∼156–312 nC/m at room temperature.
Study for optical manipulation of a surfactant-covered droplet using lattice Boltzmann method
Authors: Choi Se Bin , Kondaraju Sasidhar , Sang Lee Joon
Published: March 2014

In this study, we simulated deformation and surfactant distribution on the interface of a surfactant-covered droplet using optical tweezers as an external source. Two optical forces attracted a single droplet from the center to both sides. This resulted in an elliptical shape deformation. The droplet deformation was characterized as the change of the magnitudes of surface tension and optical force. In this process, a non-linear relationship among deformation, surface tension, and optical forces was observed. The change in the local surfactant concentration resulting from the application of optical forces was also analyzed and compared with the concentration of surfactants subjected to an extensional flow. Under the optical force influence, the surfactant molecules were concentrated at the droplet equator, which is totally opposite to the surfactants behavior under extensional flow, where the molecules were concentrated at the poles. Lastly, the quasi-equilibrium surfactant distribution was obtained by combining the effects of the optical forces with the extensional flow. All simulations were executed by the lattice Boltzmann method which is a powerful tool for solving micro-scale problems.
Mesoporous Carbon-supported Cu/ZnO for Methanol Synthesis from Carbon Dioxide
Authors: Duan Huamei , Yang Yunxia , Singh Ranjeet , Chiang Ken , Wang Steven , Xiao Penny , Patel Jim , Danaci David , Burke Nick , Zhai Yuchun , Webley Paul A.
Published: March 2014

Catalysts based on Cu/CuO–ZnO supported on mesoporous carbon (FDU-15) were synthesised and tested for methanol production from CO2 and H2. The catalytic activity was strongly dependent on the method by which the Cu and Zn components were loaded onto the carbon support. Three synthetic methods were trialled and the materials produced were characterised by various techniques. The materials with better contact between the Cu/CuO and ZnO particles were catalytically more active towards methanol production (CZC-3 > CZC-2 > CZC-1). The methanol production rate for CZC-3 (7.3 mmol g–1 h–1) was higher, on a catalyst weight basis, than that of a commercial catalyst (5.6 mmol g–1 h–1). Also, CZC-3 had a higher turnover frequency (1.8 × 10–2 s–1) than the commercial catalyst (0.2 × 10–2 s–1). This work demonstrates that Cu/CuO and ZnO particles supported on mesoporous carbon, prepared by an appropriate method, are promising catalysts for methanol synthesis from carbon dioxide.
Alcohol and Associated Characteristics among Older Persons Living with Human Immunodeficiency Virus on Antiretroviral Therapy
Authors: Williams Emily C. , Bradley Katharine A. , Balderson Benjamin H. , McClure Jennifer B. , Grothaus Lou , McCoy Katryna , Rittmueller Stacey E. , Catz Sheryl L.
Published: March 2014

Background

Alcohol use, and particularly unhealthy alcohol use, is associated with poor human immunodeficiency virus (HIV)-related outcomes among persons living with HIV (PLWH). Despite a rapidly growing proportion of PLWH ≥50 years, alcohol use and its associated characteristics are underdescribed in this population. The authors describe alcohol use, severity, and associated characteristics using data from a sample of PLWH ≥50 years who participated in a trial of a telephone-based intervention to improve adherence to antiretroviral therapy (ART).

Methods

Participants were recruited from acquired immunodeficiency syndrome (AIDS) service organizations in 9 states and included PLWH ≥50 years who were prescribed ART, reported suboptimal adherence at screening (missing >1.5 days of medication or taking medications 2 hours early or late on >3 days in the 30 days prior to screening), and consented to participate. The AUDIT-C (Alcohol Use Disorders Identification Test—Consumption) alcohol screen, sociodemographic characteristics, substance use, and mental health comorbidity were assessed at baseline. AUDIT-C scores were categorized into nondrinking, low-level drinking, and mild-moderate unhealthy, and severe unhealthy drinking (0, 1–3, 4–6, and 7–12, respectively). Analyses described and compared characteristics across drinking status (any/none) and across AUDIT-C categories among drinkers.

Results

Among 447 participants, 57% reported drinking in the past year (35%, 15%, and 7% reported low-level drinking, mild-moderate unhealthy drinking, and severe unhealthy drinking, respectively). Any drinking was most common among men and those who were lesbian, gay, bisexual, or transgender (LGBT), married/partnered, had received past-year alcohol treatment, and never used injection drugs ( P values all <.05). Differences in race, employment status, past-year alcohol treatment, and positive depression screening ( P values all <.05) were observed across AUDIT-C categories, with African American race, less than full-time employment, past-year alcohol treatment, and positive depression screening being most common among those with the most severe unhealthy drinking.

Conclusions

In this sample of older PLWH with suboptimal ART adherence, a majority reported past-year alcohol use and 22% screened positive for unhealthy alcohol use. Any and unhealthy alcohol use were associated with demographics, depression, and substance use history. Further research is needed regarding alcohol use among older PLWH.
Uniqueness of solutions to Schrödinger equations on 2-step nilpotent Lie groups
Authors: Ludwig Jean , Müller Detlef
Published: March 2014

Let

g

=

g

1

⊕

g

2

,
[

g

,

g

]
=

g

2

,

\mathfrak {g}=\mathfrak {g}_1\oplus \mathfrak {g}_2,[\mathfrak {g},\mathfrak {g}] =\mathfrak {g}_2,

a nilpotent Lie algebra of step 2,

V
1

,
⋯
,

V
m

V_1,\cdots , V_m

a basis of

g

1

\mathfrak {g}_1

and

L
=

∑

j
,
k

m

a

j
k

V
j

V
k

L=\sum _{j,k}^{m}a_{jk}V_j V_k

a left-invariant differential operator on

G
=

e
x
p

(

g

)

G=\mathrm {exp} (\mathfrak {g})

, where

(

a

j
k

)

j
k

∈

M
n

(

R

)

(a_{jk})_{jk}\in M_n(\mathbb {R})

is symmetric. It is shown that if a solution

w
(
t
,
x
)

w(t,x)

to the Schrödinger equation

∂
t

w
(
t
,
g
)
=
i
L
w
(
t
,
g
)
,

\partial _t w(t,g)=i Lw(t,g),

g
∈
G
,
t
∈

R

,
w
(
0
,
g
)
=
f
(
g
)

g\in G, t\in \mathbb {R}, w(0,g)=f(g)

, satisfies a suitable Gaussian type estimate at time

t
=
0

t= 0

and at some time

t
=
T
≠
0

t=T\ne 0

, then

w
=
0

w=0

. The proof is based on Hardy’s uncertainty principle, on explicit computations within Howe’s oscillator semigroup and on methods developed by Fulvio Ricci and the second author. Our results extend work by Ben Saïd, Thangavelu and Dogga on the Schrödinger equation associated to the sub-Laplacian on Heisenberg type groups.
The membrane scaffold CD82 regulates cell adhesion by altering α4 integrin stability and molecular density
Authors: Termini Christina M. , Cotter Maura L. , Marjon Kristopher D. , Buranda Tione , Lidke Keith A. , Gillette Jennifer M.
Published: March 2014

Hematopoietic stem/progenitor cell (HSPC) interactions with the bone marrow microenvironment are important for maintaining HSPC self-renewal and differentiation. In recent work, we identified the tetraspanin protein, CD82, as a regulator of HPSC adhesion and homing to the bone marrow, although the mechanism by which CD82 mediated adhesion was unclear. In the present study, we determine that CD82 expression alters cell–matrix adhesion, as well as integrin surface expression. By combining the superresolution microscopy imaging technique, direct stochastic optical reconstruction microscopy, with protein clustering algorithms, we identify a critical role for CD82 in regulating the membrane organization of α4 integrin subunits. Our data demonstrate that CD82 overexpression increases the molecular density of α4 within membrane clusters, thereby increasing cellular adhesion. Furthermore, we find that the tight packing of α4 into membrane clusters depend on CD82 palmitoylation and the presence of α4 integrin ligands. In combination, these results provide unique quantifiable evidence of CD82’s contribution to the spatial arrangement of integrins within the plasma membrane and suggest that regulation of integrin density by tetraspanins is a critical component of cell adhesion.
The age distribution of stellar clusters in M83
Authors: Silva-Villa E. , Adamo A. , Bastian N. , Fouesneau M. , Zackrisson E.
Published: March 2014

In order to empirically determine the time-scale and environmental dependence of stellar cluster disruption, we have undertaken an analysis of the unprecedented multipointing (seven), multiwavelength (U, B, V, Hα, and I) Hubble Space Telescope imaging survey of the nearby, face-on spiral galaxy M83. The images are used to locate stellar clusters and stellar associations throughout the galaxy. Estimation of cluster properties (age, mass, and extinction) was done through a comparison of their spectral energy distributions with simple stellar population models. We constructed the largest catalogue of stellar clusters and associations in this galaxy to-date, with ∼1800 sources with masses above ∼5000 M⊙ and ages younger than ∼300 Myr. In this Letter, we focus on the age distribution of the resulting clusters and associations. In particular, we explicitly test whether the age distributions are related with the ambient environment. Our results are in excellent agreement with previous studies of age distributions in the centre of the galaxy, which gives us confidence to expand out to search for similarities or differences in the other fields which sample different environments. We find that the age distribution of the clusters inside M83 varies strongly as a function of position within the galaxy, indicating a strong correlation with the galactic environment. If the age distributions are approximated as a power law of the form ${\frac{\mathrm{d} N}{\mathrm{d}t}}\propto t^{\zeta }$, we find ζ values between 0 and −0.62 (ζ ∼ −0.40 for the whole galaxy), in good agreement with previous results and theoretical predictions.
Effects of Lime‐Cooking on Carotenoids Present in Masa and Tortillas Produced from Different Types of Maize
Authors: Gutiérrez‐Uribe Janet A. , Rojas‐García Carlos , García‐Lara Silverio , Serna‐Saldivar Sergio O.
Published: March 2014

Yellow and white maize kernels, masas, tortillas, and nejayote solids were analyzed in terms of lutein, zeaxanthin, cryptoxanthin, β‐carotene, and lipophilic antioxidant (AOX) capacity. The germplasm analyzed included two normal yellow maize, two high‐carotenoid genotypes, and one white for comparison purposes. In general, the yellow maize required 34% more lime‐cooking time compared with the white counterpart. Lime‐cooking significantly changed the extractability of carotenoids in masa and tortillas. No carotenoids were detected in the steepwater or nejayote. The lipophilic AOX activity increased 280‐fold from kernel to masa, but only 70% was retained in the baked tortillas. When masa was baked into tortillas, less than 10% of the carotenoids were retained because of the high temperatures used during baking. Interestingly, tortillas made with the maize kernels with the highest carotenoid content did not have the highest amount of these phytochemicals. Therefore, maize varieties should be evaluated based on the carotenoid content in finished food products instead of the amounts originally found in raw kernels.
Molecular and Chemical Characterization of a New Waxy Allele in Barley (Hordeum vulgare L.)
Authors: Hu Gongshe , Burton Charlotte , Hong Zonglie
Published: March 2014

Barley m38 mutant was selected for its high level of mixed‐linkage (1,3),(1,4)‐β‐d‐glucan (MLG) in the grain. This elevated level of MLG was found to be associated with decreased amylose accumulation as well as other chemical composition alterations. Molecular characterization results revealed m38 as a new allele of the Waxy gene, encoding an endosperm‐specific granule‐bound starch synthase I (GBSSI). Additional mapping data from amylose phenotype and GBSSI gene specific markers supported the conclusion of the GBSSI mutation in m38. The m38 locus contains a nucleotide alteration that would result in the substitution of glycine at position 263 with serine in the putative adenosine‐5′‐diphosphate‐glucose binding domain. This amino acid substitution alters loop structures on the exterior surface of the folded protein and may affect its enzyme activity. Characterizations of m38 in this report provide for a new allele of the Waxy gene and additional evidence of pleiotropic effects on other chemical components including increased MLG, fructans, and fats and decreased amylose and protein.
Prevalence and Stability of Qualitative QoI Resistance in Populations of Venturia inaequalis in the Northeastern United States
Authors: Frederick Zachary A. , Villani Sara M. , Cooley Daniel R. , Biggs Alan R. , Raes Jessica J. , Cox Kerik D.
Published: March 2014

Quinone-outside-inhibitor (QoI) fungicides are a safe and effective means of managing apple scab caused by Venturia inaequalis. To determine the prevalence of both quantitative (partial) and qualitative (complete) QoI resistance in V. inaequalis in the northeastern United States, we sampled single-lesion conidial isolates (n = 4,481) from 120 commercial and research orchards from 2004 to 2011 with a range of exposure to QoI fungicides from none to several applications a year. In all, 67% of these orchard populations of V. inaequalis were sensitive to QoI fungicides, 28% exhibited QoI practical resistance, and 5% were not sensitive QoI fungicides but had not become practically resistant. Isolates with qualitative QoI resistance, conferred by the G143A cytochrome b gene mutation, were found in 13 of the 34 QoI-resistant orchard populations. To evaluate the stability of the G143A mutation, 27 isolates were selected from different orchard populations to represent the scope of regional populations. These isolates were subcultured continuously in the presence or absence of the QoI fungicide trifloxystrobin. All isolates that initially possessed qualitative resistance maintained the resistant genotype (G143A) for six transfers over 6 months in both the absence and presence of trifloxystrobin. Given the observed QoI resistance in orchard populations of V. inaequalis and the stability of the G143A mutation in individual isolates, apple scab management paradigms must encompass strategies to limit selection of QoI resistance in the sensitive orchard populations remaining in the region.
Impacts of Crop Variety and Time of Inoculation on the Susceptibility and Tolerance of Winter Wheat to Wheat streak mosaic virus
Authors: Miller Z. , Menalled F. , Ito D. , Moffet M. , Burrows M.
Published: March 2014

Plant genotype, age, size, and environmental factors can modify susceptibility and tolerance to disease. Understanding the individual and combined impacts of these factors is needed to define improved disease management strategies. In the case of Wheat streak mosaic virus (WSMV) in winter wheat, yield losses and plant susceptibility have been found to be greatest when the crop is exposed to the virus in the fall in the central and southern Great Plains. However, the seasonal dynamics of disease risk may be different in the northern Great Plains, a region characterized by a relatively cooler fall conditions, because temperature is known to modify plant–virus interactions. In a 2-year field study conducted in south-central Montana, we compared the impact of fall and spring WSMV inoculations on the susceptibility, tolerance, yield, and grain quality of 10 winter wheat varieties. Contrary to previous studies, resistance and yields were lower in the spring than in the fall inoculation. In all, 5 to 7% of fall-inoculated wheat plants were infected with WSMV and yields were often similar to uninoculated controls. Spring inoculation resulted in 45 to 57% infection and yields that were 15 to 32% lower than controls. Although all varieties were similarly susceptible to WSMV, variations in tolerance (i.e., yield losses following exposure to the virus) were observed. These results support observations that disease risk and impacts differ across the Great Plains. Possible mechanisms include variation in climate and in the genetic composition of winter wheat and WSMV across the region.
Heteroplasmy of the cytochrome b Gene in Venturia inaequalis and Its Involvement in Quantitative and Practical Resistance to Trifloxystrobin
Authors: Villani Sara M. , Cox Kerik D.
Published: March 2014

Quantitative (partial) and qualitative (complete) resistance responses to quinone outside inhibitor (QoI) fungicides have been documented for the apple scab pathogen Venturia inaequalis. Resistance monitoring efforts have traditionally focused on the detection of qualitative resistance based on a single point mutation, G143A, within the cytochrome b (cyt b) gene. In order to better understand the role of heteroplasmy of the cyt b gene in the QoI resistance response for isolates and populations of V. inaequalis, an allele-specific quantitative polymerase chain reaction was developed to quantify the relative abundance of the A143 (resistant) allele in 45 isolates of V. inaequalis with differing in vitro resistance responses to the QoI fungicide trifloxystrobin. Although a high relative abundance of the A143 allele (>62%) was associated with isolates with high resistance responses (50 to 100% relative growth on trifloxystrobin-amended medium), heteroplasmy of the cyt b gene was not the primary factor involved in isolates with moderate resistance responses (29 to 49% relative growth). The relative abundance of the A143 allele in isolates with moderate resistance to trifloxystrobin rarely exceeded 8%, suggesting that other resistance mechanisms are involved in moderate resistance and, therefore, that the Qol resistance response is polygenic. In research orchards where QoI fungicides failed to control apple scab (practical resistance), field trials were conducted to demonstrate the link between practical resistance and the abundance of the A143 allele. Relative abundance of the A143 allele in these orchard populations exceeded 20% in 2011 and 2012. Similarly, of the eight additional commercial orchards screened in 2011, the relative abundance of the A143 allele always exceeded 20% in those with QoI practical resistance. Although heteroplasmy of the cyt b gene did not entirely explain the response of isolates with moderate resistance to QoIs, the relative abundance of A143 in orchard populations of V. inaequalis helps to explain the point of emergence for practical resistance to trifloxystrobin across several orchard populations with differing production histories.
Arthropods Vector Grapevine Trunk Disease Pathogens
Authors: Moyo P. , Allsopp E. , Roets F. , Mostert L. , Halleen F.
Published: March 2014

Arthropod-mediated dispersal of pathogens is known in many cropping systems but has never been demonstrated for grapevine trunk disease pathogens. Arthropods from vineyards were screened for the presence of pathogens associated with Petri disease and esca using cultural and molecular techniques. The ability of the most abundant pathogen-carrying species to inoculate healthy grapevine vascular tissues was also determined. Millipedes and ants were allowed to associate with a DsRed- Express-transformed Phaeomoniella chlamydospora, after which they were exposed to freshly pruned healthy grapevines under controlled conditions and wounds were monitored for subsequent infection. In addition, the possibility of millipede excreta, commonly found on pruning wounds in the field, to act as inoculum source was determined. A diverse arthropod fauna was associated with declining grapevines and many of these carried trunk disease pathogens. However, spiders, the ant Crematogaster peringueyi, and the millipede Ommattoiulus moreleti were the most abundant pathogen carriers. The ant and millipede species fed on pruning wound sap and effectively transmitted trunk disease pathogens. Millipede excreta contained viable spores of Phaeomoniella chlamydospora and may serve as an inoculum source. Numerous arthropods, including beneficial predators, are potential vectors of grapevine trunk disease pathogens. Our results highlight the need for an integrated approach, including targeted management of ants and millipedes at the time of pruning, to limit the spread of grapevine trunk diseases.
Pathogenesis-Related Protein Expression in the Apoplast of Wheat Leaves Protected Against Leaf Rust Following Application of Plant Extracts
Authors: Naz Rabia , Bano Asghari , Wilson Neil L. , Guest David , Roberts Thomas H.
Published: March 2014

Leaf rust (Puccinia triticina) is a major disease of wheat. We tested aqueous leaf extracts of Jacaranda mimosifolia (Bignoniaceae), Thevetia peruviana (Apocynaceae), and Calotropis procera (Apocynaceae) for their ability to protect wheat from leaf rust. Extracts from all three species inhibited P. triticina urediniospore germination in vitro. Plants sprayed with extracts before inoculation developed significantly lower levels of disease incidence (number of plants infected) than unsprayed, inoculated controls. Sprays combining 0.6% leaf extracts and 2 mM salicylic acid with the fungicide Amistar Xtra at 0.05% (azoxystrobin at 10 μg/liter + cyproconazole at 4 μg/liter) reduced disease incidence significantly more effectively than sprays of fungicide at 0.1% alone. Extracts of J. mimosifolia were most active, either alone (1.2%) or in lower doses (0.6%) in combination with 0.05% Amistar Xtra. Leaf extracts combined with fungicide strongly stimulated defense-related gene expression and the subsequent accumulation of pathogenesis-related (PR) proteins in the apoplast of inoculated wheat leaves. The level of protection afforded was significantly correlated with the ability of extracts to increase PR protein expression. We conclude that pretreatment of wheat leaves with spray formulations containing previously untested plant leaf extracts enhances protection against leaf rust provided by fungicide sprays, offering an alternative disease management strategy.
Ontogenic Resistance of Leaves and Fruit, and How Leaf Folding Influences the Distribution of Powdery Mildew on Strawberry Plants Colonized by Podosphaera aphanis
Authors: Asalf Belachew , Gadoury David M. , Tronsmo Anne Marte , Seem Robert C. , Dobson Andrew , Peres Natalia A. , Stensvand Arne
Published: March 2014

Ontogenic or age-related resistance has been noted in many pathosystems but is less often quantified or expressed in a manner that allows the concept to be applied in disease management programs. Preliminary studies indicated that leaves and fruit of three strawberry cultivars rapidly acquired ontogenic resistance to the powdery mildew pathogen, Podosphaera aphanis. In the present study, we quantify the development of ontogenic resistance in controlled inoculations of 10 strawberry cultivars using diverse isolates of P. aphanis in New York and Florida, USA, and in Norway. We report the differential and organ-specific development of ontogenic resistance in the receptacle and externally borne strawberry achenes. We further report that rapid development of ontogenic resistance prior to unfolding of emergent leaves, rather than differential susceptibility of adaxial versus abaxial leaf surfaces, may explain the commonly observed predominance of powdery mildew on the lower leaf surfaces. Susceptibility of leaves and fruit declined exponentially with age. Receptacle tissue of berries inoculated at four phenological stages from bloom to ripe fruit became nearly immune to infection approximately 10 to 15 days after bloom, as fruit transitioned from the early green to the late green or early white stage of berry development, although the achenes remained susceptible for a longer period. Leaves also acquired ontogenic resistance early in their development, and they were highly resistant shortly after unfolding and before the upper surface was fully exposed. No significant difference was found in the susceptibility of the adaxial versus abaxial surfaces. The rapid acquisition of ontogenic resistance by leaves and fruit revealed a narrow window of susceptibility to which management programs might be advantageously adapted.
Burkholderia
cordobensis sp. nov., from agricultural soils
Authors: Draghi Walter O. , Peeters Charlotte , Cnockaert Margo , Snauwaert Cindy , Wall Luis G. , Zorreguieta Angeles , Vandamme Peter
Published: March 2014

Two Gram-negative, rod-shaped bacteria were isolated from agricultural soils in Córdoba province in central Argentina. Their 16S rRNA gene sequences demonstrated that they belong to the genus

Burkholderia

, with

Burkholderia zhejiangensis

as most closely related formally named species; this relationship was confirmed through comparative gyrB sequence analysis. Whole-cell fatty acid analysis supported their assignment to the genus

Burkholderia

. Burkholderia sp. strain YI23, for which a whole-genome sequence is available, represents the same taxon, as demonstrated by its highly similar 16S rRNA (100 % similarity) and gyrB (99.1–99.7 %) gene sequences. The results of DNA–DNA hybridization experiments and physiological and biochemical characterization further substantiated the genotypic and phenotypic distinctiveness of the Argentinian soil isolates, for which the name Burkholderia cordobensis sp. nov. is proposed, with strain MMP81T ( = LMG 27620T = CCUG 64368T) as the type strain.
Modulation of antibiotic resistance and induction of a stress response in Pseudomonas aeruginosa by silver nanoparticles
Authors: Markowska Katarzyna , Grudniak Anna M. , Krawczyk Krzysztof , Wróbel Izabela , Wolska Krystyna I.
Published: March 2014

The objective of this study was to characterize the effects of silver nanoparticles on Pseudomonas aeruginosa. Their interactions with several conventional antibiotics and ability to induce a stress response were examined. Interactions between silver nanoparticles (AgNPs) and antibiotics against free-living cells and biofilm of P. aeruginosa were studied using the chequerboard method and time-kill assays. The ability of AgNPs to induce a stress response was determined by evaluation of cellular levels of the DnaK and HtpG chaperones using SDS-PAGE and Western blot analysis. Synergistic activity against free-living P. aeruginosa between AgNPs and ampicillin, streptomycin, rifampicin and tetracycline, but not oxacillin, ciprofloxacin, meropenem or ceftazidime, was demonstrated by the chequerboard method. No such interactions were observed against P. aeruginosa biofilm. The results of time-kill assays confirmed synergy only for the AgNPs–streptomycin combination. AgNPs induced the expression of chaperone DnaK. No induction of the HtpG chaperone was detected. In conclusion, AgNPs not only display potent bactericidal activity against P. aeruginosa, but also act synergistically with several conventional antibiotics to enhance their effect against free-living bacteria as determined by the chequerboard method. The time-kill assay proved synergy between AgNPs and streptomycin only. The ability of AgNPs to induce the major chaperone protein DnaK may influence bacterial resistance to antimicrobials.
Evidence of extrahepatic replication of hepatitis E virus in human placenta
Authors: Bose Purabi Deka , Das Bhudev Chandra , Hazam Rajib Kishore , Kumar Ashok , Medhi Subhash , Kar Premashis
Published: March 2014

The incidence and severity of hepatitis E virus (HEV) infection in pregnant women is high in developing countries. Transplacental transmission of HEV in the third trimester of pregnancy has been found to be associated with high fetal mortality. Based on this evidence and in the absence of reports on HEV replication in extrahepatic sites, this study was carried out to investigate if HEV replication occurs in the placenta of infected mothers. The study included 68 acute viral hepatitis (AVH) and 22 acute liver failure (ALF) pregnant patients. Viral RNA was extracted from blood and placenta. HEV replication in placenta was confirmed by a replicative negative-strand-specific reverse transcriptase PCR. Viral load was estimated by real-time PCR. Immunohistochemical studies were also carried out for in situ detection of HEV in placental tissue sections. Replicative HEV RNA was detectable only in the placenta in ALF and AVH cases and not in blood samples. Positive staining of placental tissue sections with HEV antibody against the viral structural protein ORF3 was observed. HEV replication in placenta also correlated with fetal and maternal mortality in ALF patients. It is demonstrated for the first time that HEV replication occurs in human placenta and that placenta may be a site of extrahepatic replication of HEV in humans.
Industry classification and the efficiency of intra-industry information transfers
Authors: Y. Chung Dennis , Hrazdil Karel , Trottier Kim
Published: March 2014

Purpose

– Motivated by recent studies that demonstrate the superiority of the Global Industry Classification System (GICS) relative to the Standard Industry Classification (SIC) system in capital market research, the authors revisit the stock market anomaly documented by Thomas and Zhang (TZ) (“Overreaction to intra-industry information transfers?” Journal of Accounting Research, Vol. 46, pp. 909-940) and analyze whether the anomaly based on SIC remains evident when intra-industry information transfers are based on the GICS. The paper aims to discuss these issues.

Design/methodology/approach

– The authors first replicate TZ and test whether stock prices of late announcers in response to earnings reported by early announcers in the same SIC industry are significantly related to subsequent price responses of late announcers to their own earnings reports. In the multivariate setting, the authors then evaluate whether the magnitude and significance of the overreaction anomaly changes under the more comprehensive GICS and across different time periods.

Findings

– The authors first confirm the over-reaction anomaly based on SIC as documented by TZ. Utilizing a larger sample of firms based on the GICS and extending TZ for a new time period, the authors then demonstrate that the overreaction anomaly disappears during recent years, a period that is characterized by markedly higher trading activity.

Research limitations/implications

– The findings provide new insights and contributions to the debate on whether or not market significantly misprices information transfers.

Originality/value

– The authors are first to utilize the GICS in evaluating intra-industry information transfers.
The relationship between organizational slack and innovation: revisited
Authors: Terry Mousa Fariss , Chowdhury Jaideep
Published: March 2014

Purpose

– The slack-innovation relationship has interested scholars for years. The authors aim to delve into the impact of financial slack on firm innovation by replicating a classic study arguing that this relationship has an inverse U-shape.

Design/methodology/approach

– The sample consists of all US firms that were publicly traded between 1993 and 2011. The authors employ the standard econometrics methodology of panel regression with firm-fixed effect and time-fixed effect to estimate the regression equation of firm innovation on financial slack.

Findings

– The authors find that the relationship between financial slack and R&D investments is similar to that suggested by earlier authors, thus enhancing the generalizability of this important finding in management research. The authors also find that this relationship holds even during economic downturns.

Originality/value

– The authors replicate Nohria and Gulati's classic study by considering the impact of slack on innovation. The authors also move away from survey data, as used by Nohria and Gulati. The authors utilize actual firm-level data for a large sample of US publicly traded firms from 1993 to 2011, thus enhancing the generalizability of these findings.
The influence of the structure of employees on sensory quality of restaurants' food
Authors: Tešanovic Dragan , Krasavcic Milovan , Miro Kalenjuk Bojana , Portic Milijanko , Gagic Snježana
Published: March 2014

Purpose

– The aim of this paper is to determine the sensory quality of food in restaurants by professional food evaluators and to research the impact of education, age and number of employees on the quality of food.

Design/methodology/approach

– In the first phase five trained food tasters evaluated the sensory quality of food. In the second phase, the analysis of the structure of employees was done by establishing their level of education, age and number of employees. In the third phase the regression and correlation analysis was done with the aim to establish the impact of the level of education, age and number of employees on the sensory quality of food.

Findings

– The sensory evaluation has shown that the evaluated food is of moderate quality. Correlation matrix has shown that the education level of employees has a high impact on the sensory quality of food. There is a correlation between the number of employees, their age and their education.

Practical implications

– Obtained results are the indicators of the quality of food in restaurants in the region and they can serve for the improvement of quality. They have shown that education and staff training can contribute to a better quality of food. Established methodology can also contribute to the practical evaluation of quality.

Originality/value

– This paper is reflected on the specific application of methodology of the sensory analysis of food in restaurants. The paper pointed to the impact of employees on the sensory quality of food by statistical methods. Statistical results which point to the great impact of the level of education of employees on the sensory quality of food in restaurants are particularly valuable.