bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of a roof tile-shaped out-of-plane vibrational mode in aluminum-nitride-actuated self-sensing micro-resonators for liquid monitoring purposes
Authors: Kucera Martin , Wistrela Elisabeth , Pfusterschmied Georg , Ruiz-Díez Víctor , Manzaneque Tomás , Luis Sánchez-Rojas José , Schalko Johannes , Bittner Achim , Schmid Ulrich
Published: June 2014

This Letter reports on an advanced out-of-plane bending mode for aluminum-nitride (AlN)-actuated cantilevers. Devices of different thickness were fabricated and characterized by optical and electrical measurements in air and liquid media having viscosities up to 615 cP and compared to the classical out-of-plane bending and torsional modes. Finite element method eigenmode analyses were performed showing excellent agreement with the measured mode shapes and resonance frequencies. Quality factors (Q-factor) and the electrical behavior were evaluated as a function of the cantilever thickness. A very high Q-factor of about 197 was achieved in deionized water at a low resonance frequency of 336 kHz, being up to now, the highest quality factor reported for cantilever sensors in liquid media. Compared to the quality factor of the common fundamental out-of-plane bending mode, a 5 times higher Q-factor was achieved. Furthermore, the strain related conductance peak of the roof tile-shaped mode is superior. Compared to any out-of-plane bending mode, this combination of most beneficial properties is unique and make this mode superior for a large variety of resonator-based sensing applications.
A van der Waals density functional theory comparison of metal decorated graphene systems for hydrogen adsorption
Authors: Wong Janet , Yadav Shwetank , Tam Jasmine , Veer Singh Chandra
Published: June 2014

Previous Density Functional Theory (DFT) studies on metal decorated graphene generally use local density approximation (LDA) or generalized gradient approximation (GGA) functionals which can cause inaccuracies in hydrogen binding energies as they neglect van der Waals (vdW) interactions and are difficult to compare due to their widely varying simulation parameters. We investigated the hydrogen binding ability of several metals with a consistent set of simulations using the GGA functional and incorporated vdW forces through the vdW-DF2 functional. Metal adatom anchoring on graphene and hydrogen adsorption ability for both single and double sided decoration were studied for eight metals (Al, Li, Na, Ca, Cu, Ni, Pd, and Pt). It was found that the vdW correction can have a significant impact on both metal and hydrogen binding energies. The vdW-DF2 functional led to stronger metal adatom and hydrogen binding for light metals in comparison to GGA results, while heavier transition metals displayed the opposite behaviour but still produced stronger hydrogen binding energies than light metals. Nickel was found to be the best balance between hydrogen binding ability for reversible storage and low weight. The effects on hydrogen binding energy and maximum achievable hydrogen gravimetric density were analyzed for Ni-graphene systems with varying metal coverage. Lower metal coverage was found to improve hydrogen binding but decrease hydrogen gravimetric density. The highest achieved Ni-graphene system gravimetric density was 6.12 wt. %.
General anesthesia suppresses normal heart rate variability in humans
Authors: Matchett Gerald , Wood Philip
Published: June 2014

The human heart normally exhibits robust beat-to-beat heart rate variability (HRV). The loss of this variability is associated with pathology, including disease states such as congestive heart failure (CHF). The effect of general anesthesia on intrinsic HRV is unknown. In this prospective, observational study we enrolled 100 human subjects having elective major surgical procedures under general anesthesia. We recorded continuous heart rate data via continuous electrocardiogram before, during, and after anesthesia, and we assessed HRV of the R-R intervals. We assessed HRV using several common metrics including Detrended Fluctuation Analysis (DFA), Multifractal Analysis, and Multiscale Entropy Analysis. Each of these analyses was done in each of the four clinical phases for each study subject over the course of 24 h: Before anesthesia, during anesthesia, early recovery, and late recovery. On average, we observed a loss of variability on the aforementioned metrics that appeared to correspond to the state of general anesthesia. Following the conclusion of anesthesia, most study subjects appeared to regain their normal HRV, although this did not occur immediately. The resumption of normal HRV was especially delayed on DFA. Qualitatively, the reduction in HRV under anesthesia appears similar to the reduction in HRV observed in CHF. These observations will need to be validated in future studies, and the broader clinical implications of these observations, if any, are unknown.
Electromagnetic complementary media with arbitrary geometries and non-conformal boundaries
Authors: Liu Guochang , Li Chao , Chen Chao , Fang Guangyou
Published: June 2014

A generalized folded transformation procedure is presented for the space with arbitrary shapes. General expressions for the constitute parameters of complementary media are deduced, which can be readily applied to design complementary media based transformation optics devices (CMTOD) with arbitrary shapes. It's no longer limited to the situation when the inner and outer boundaries of the CMTOD are conformal or similar shapes, and can be available for the non-conformal situations. Three kinds of CMTOD are designed and studied, which involves a super-lens, an external cloak that hides object outside the cloaking shell, and an illusion optics device that transforms one object to another. Full-wave simulations are carried out to validate the proposed approach. The generalization introduced here makes a step forward for the flexible design of CMTOD with arbitrary geometries.
Spot size dependence of laser accelerated protons in thin multi-ion foils
Authors: Liu Tung-Chang , Shao Xi , Liu Chuan-Sheng , Eliasson Bengt , Wang Jyhpyng , Chen Shih-Hung
Published: June 2014

We present a numerical study of the effect of the laser spot size of a circularly polarized laser beam on the energy of quasi-monoenergetic protons in laser proton acceleration using a thin carbon-hydrogen foil. The used proton acceleration scheme is a combination of laser radiation pressure and shielded Coulomb repulsion due to the carbon ions. We observe that the spot size plays a crucial role in determining the net charge of the electron-shielded carbon ion foil and consequently the efficiency of proton acceleration. Using a laser pulse with fixed input energy and pulse length impinging on a carbon-hydrogen foil, a laser beam with smaller spot sizes can generate higher energy but fewer quasi-monoenergetic protons. We studied the scaling of the proton energy with respect to the laser spot size and obtained an optimal spot size for maximum proton energy flux. Using the optimal spot size, we can generate an 80 MeV quasi-monoenergetic proton beam containing more than 108 protons using a laser beam with power 250 TW and energy 10 J and a target of thickness 0.15 wavelength and 49 critical density made of 90% carbon and 10% hydrogen.
Effects of nitrate and humic acid on enrofloxacin photolysis in an aqueous system under three light conditions: kinetics and mechanism
Authors: Li Yang , Niu Junfeng , Shang Enxiang , Zheng Mengyuan , Luan Tianlai
Published: June 2014

Environmental context
Photolysis is one of the most important transformation pathways in natural ecosystem for enrofloxacin (Enro), which is a hazard for humans and other living organisms. The effects of NO3– and humic acid on Enro photolysis were found to be light-source dependent. These results are of significance toward the goal of providing insight into the transformation and fate of Enro in the environment.

Abstract
The light-source-dependent effects of NO3– and humic acid (HA) on enrofloxacin (Enro) photolysis kinetics in aqueous solutions were investigated under solar, UV-254 and UV-365 lamp irradiation. NO3– was found to suppress Enro photolysis through competitive photoabsorption under UV-365 irradiation, whereas it accelerated Enro photolysis under UV-254 and solar irradiation as a result of NO3– photosensitisation. Similarly, HA enhanced, inhibited or had no obvious effect on Enro photolysis under different light irradiation conditions. Even under the same light irradiation conditions, the effect of HA on Enro photolysis varied with HA concentration. The reactive oxygen species (ROS) scavenger experiments demonstrated that Enro photolysis undergoes •OH- and 1O2-mediated self-sensitised photolysis. The photolysis pathway of Enro involved decarboxylation, defluorination and piperazinyl N4-dealkylation reactions. The toxicity towards Vibrio fischeri luminescent bacteria under solar irradiation was different from that under UV irradiation. The 90-min toxicity of Enro and its photoproducts increased under solar irradiation but decreased under UV-365 and UV-254 irradiation compared to the initial Enro toxicity, which indicated that UV light not only had higher photolysis efficiency but also posed less toxicity towards bacteria than solar.
Post-anthesis heat and a Gpc-B1 introgression have similar but non-additive effects in bread wheat
Authors: Maphosa Lancelot , Collins Nicholas C. , Taylor Julian , Mather Diane E.
Published: June 2014

High temperatures during grain filling can reduce the yield of wheat and affect its grain protein concentration. The Gpc-B1 locus of wheat also affects grain protein concentration, but it is not known whether its effects interact with those of heat. The aim of this study was to investigate the effects of high temperature in lines with and without functional (high-protein) alleles at Gpc-B1. A highly replicated experiment was conducted in a glasshouse under control conditions (24/18°C, 14/10 h day/night), with half of the plants of each line or cultivar put into a heat chamber (37/27°C, 14/10 h day/night) at 15 days after anthesis for 3 days. Backcross derivatives with the Gpc-B1 introgression segment differed from their recurrent parents more than those without that segment. In some respects, the effects of the Gpc-B1 introgression were similar to those of the heat treatment: both could accelerate peduncle senescence, increase grain protein content and increase the percentage of unextractable polymeric protein. Unlike the heat treatment, Gpc-B1 did not reduce grain weight, indicating that factors that hasten senescence do not necessarily limit grain size. The presence of the Gpc-B1 segment did not exacerbate the effects of heat stress on any trait.
Feasibility of an intervention to enhance preventive care for people with low health literacy in primary health care
Authors: Faruqi Nighat , Lloyd Jane , Ahmad Raghib , Yeong Lin-Lee , Harris Mark
Published: June 2014

The objective of the study was to explore the feasibility of an intervention that enhances preventive care for primary care patients with low health literacy. A mixed method study was conducted in four Sydney general practices in areas of socioeconomic disadvantage. The intervention included screening for low health literacy in patients aged 40–69 years, clinical record audits of care for prevention of diabetes and cardiovascular disease, and provider training and meetings. Surveys and interviews were conducted to identify providers’ approaches to, and delivery of, preventive care for people with low health literacy. Our study found variable response rates and prevalence of low health literacy. Of the eligible patients screened, 29% had low health literacy. Providers described three approaches to preventive care, which remained largely unchanged. However, they demonstrated recognition of the importance of better communication and referral support for patients with low health literacy. Fewer patients with low health literacy were identified than expected. Despite improved awareness of the need for better communication, there was limited evidence of change in providers’ approach to providing preventive care, suggesting a need for more attention towards providers’ attitudes to support these patients.
Simulated western spruce budworm defoliation reduces torching and crowning potential: a sensitivity analysis using a physics-based fire model
Authors: Cohn Gregory M. , Parsons Russell A. , Heyerdahl Emily K. , Gavin Daniel G. , Flower Aquila
Published: June 2014

The widespread, native defoliator western spruce budworm (Choristoneura occidentalis Freeman) reduces canopy fuels, which might affect the potential for surface fires to torch (ignite the crowns of individual trees) or crown (spread between tree crowns). However, the effects of defoliation on fire behaviour are poorly understood. We used a physics-based fire model to examine the effects of defoliation and three aspects of how the phenomenon is represented in the model (the spatial distribution of defoliation within tree crowns, potential branchwood drying and model resolution). Our simulations suggest that fire intensity and crowning are reduced with increasing defoliation compared with un-defoliated trees, regardless of within-crown fuel density, but torching is only reduced with decreasing crown fuel density. A greater surface fire intensity was required to ignite the crown of a defoliated compared with an un-defoliated tree of the same crown base height. The effects of defoliation were somewhat mitigated by canopy fuel heterogeneity and potential branchwood drying, but these effects, as well as computational cell size, were less pronounced than the effect of defoliation itself on fire intensity. Our study suggests that areas heavily defoliated by western spruce budworm may inhibit the spread of crown fires and promote non-lethal surface fires.
Integration of bacterial lytic polysaccharide monooxygenases into designer cellulosomes promotes enhanced cellulose degradation
Authors: Arfi Yonathan , Shamshoum Melina , Rogachev Ilana , Peleg Yoav , Bayer Edward A.
Published: June 2014

Significance

Degradation of cellulosic biomass is a key bottleneck in the development of plant-based bioenergies. Studies of cellulolytic microorganisms led to the characterization of a large range of enzymatic systems usable for cellulose breakdown, but current technologies are not efficient enough to warrant their large-scale implementation. This study aims at combining two paradigms in a single system, using a synthetic biology approach. Polysaccharide monooxygenases (redox enzymes capable of boosting cellulose degradation) were engineered to gain the ability to assemble in cellulosomal complexes. As a result of their integration in complexes, these enzymes were able to degrade cellulose at a significantly higher rate compared with the free enzymes, suggesting that this strategy could lead to more efficient technologies for lignocellulose conversion.
Differential expression of APE1 and APE2 in germinal centers promotes error-prone repair and A:T mutations during somatic hypermutation
Authors: Stavnezer Janet , Linehan Erin K. , Thompson Mikayla R. , Habboub Ghaith , Ucher Anna J. , Kadungure Tatenda , Tsuchimoto Daisuke , Nakabeppu Yusaku , Schrader Carol E.
Published: June 2014

Significance

Error-prone DNA repair of activation-induced cytidine deaminase (AID)-induced lesions in B cells is known to cause hypermutation of the antibody genes and, when coupled with selection mechanisms in germinal centers, leads to increased affinity of antibody. These lesions can also lead to substantial genomic instability that can promote lymphomagenesis, and the cause of error-prone repair is unknown. We have found that expression of an essential DNA repair protein, AP endonuclease (APE) 1, is dramatically reduced in mouse germinal center B cells where somatic hypermutation occurs. By contrast, the very inefficient homologue, APE2, becomes highly expressed. We show that APE2 promotes mutations and present a model proposing that differential expression of APE homologues in germinal centers is a major reason for error-prone repair of AID-induced lesions.
Vesiculoviral matrix (M) protein occupies nucleic acid binding site at nucleoporin pair (Rae1•Nup98)
Authors: Quan Beili , Seo Hyuk-Soo , Blobel Günter , Ren Yi
Published: June 2014

Significance

Using crystallographic and biochemical studies, we explored how a viral protein, the matrix (M) protein of vesicular stomatitis virus (VSV), affects a pair of cellular proteins: mRNA export factor 1 (Rae1) and nucleoporin Nup98. We identified Rae1 as a nucleic acid-binding protein and showed that the viral M protein mimics the phosphate backbone of any nucleic acid. This mimicry enables VSV M protein to occupy the nucleic acid binding site of Rae1. Because this site is also used as a temporary stopover by host cell mRNA on its passage through the nuclear pore, the viral M protein sabotages host cell mRNA export, thereby paving the way for exclusively cytoplasm-synthesized VSV mRNAs to take over the cell’s protein biosynthesis machineries.
Robots can be perceived as goal-oriented agents
Authors: Sciutti Alessandra , Bisio Ambra , Nori Francesco , Metta Giorgio , Fadiga Luciano , Sandini Giulio
Published: June 2014

Understanding the goals of others is fundamental for any kind of interpersonal interaction and collaboration. From a neurocognitive perspective, intention understanding has been proposed to depend on an involvement of the observer’s motor system in the prediction of the observed actions (Nyström et al. 2011; Rizzolatti & Sinigaglia 2010; Southgate et al. 2009). An open question is if a similar understanding of the goal mediated by motor resonance can occur not only between humans, but also for humanoid robots. In this study we investigated whether goal-oriented robotic actions can induce motor resonance by measuring the appearance of anticipatory gaze shifts to the goal during action observation. Our results indicate a similar implicit processing of humans’ and robots’ actions and propose to use anticipatory gaze behaviour as a tool for the evaluation of human-robot interactions. Keywords: Humanoid robot; motor resonance; anticipation; proactive gaze; action understanding
Cooperative gazing behaviors in human multi-robot interaction
Authors: Xu Tian , Zhang Hui , Yu Chen
Published: June 2014

When humans are addressing multiple robots with informative speech acts (Clark & Carlson 1982), their cognitive resources are shared between all the participating robot agents. For each moment, the user’s behavior is not only determined by the actions of the robot that they are directly gazing at, but also shaped by the behaviors from all the other robots in the shared environment. We define cooperative behavior as the action performed by the robots that are not capturing the user’s direct attention. In this paper, we are interested in how the human participants adjust and coordinate their own behavioral cues when the robot agents are performing different cooperative gaze behaviors. A novel gaze-contingent platform was designed and implemented. The robots’ behaviors were triggered by the participant’s attentional shifts in real time. Results showed that the human participants were highly sensitive when the robot agents were performing different cooperative gazing behaviors. Keywords: human-robot interaction; multi-robot interaction; multiparty interaction; eye gaze cue; embodied conversational agent
Course of maternal prosodic incitation (motherese) during early development in autism
Authors: Cassel Raquel S. , Saint-Georges Catherine , Mahdhaoui Ammar , Chetouani Mohamed , Laznik Marie Christine , Muratori Filippo , Adrien Jean-Louis , Cohen David
Published: June 2014

We examined the course of caregiver (CG) motherese and the course of the infant’s response based on home movies from two single cases: a boy with typical development (TD) and a boy with autistic development (AD). We first blindly assessed infant CG interaction using the Observer computer-based coding procedure, then analyzed speech CG production using a computerized algorithm. Finally we fused the two procedures and filtered for co-occurrence. In this exploratory study we found that the course of CG parentese differed based on gender (father vs. mother) and child status (TD vs. AD). The course of an infant’s response to CG vocalization differed according to the type of speech (motherese vs. other speech) and child status (TD vs. AD). Mothers spent more time interacting with infants, and fathers appeared to interact with their child preferentially between 12 and 18 months in the TD boy, but not in the AD boy. The TD boy responded equally well to motherese compared to other speech after 1 year of age. For the AD boy, the responses to both types of speech were lower than in the boy with TD and decreased from the second to the third semester. Keywords: Autism; motherese; early interaction; computational methods
Instrumental thinking in Translation Studies
Authors: Dizdar Dilek
Published: June 2014

This paper concentrates on instrumental thinking to analyse the conceptualization of translation in praxis and theory. First, instrumental thinking is introduced as a general mode of thinking which can be traced across different academic disciplines. A critical position is adopted with reference to Horkheimer/ Adorno and Bourdieu. Based on Bourdieu’s work on “the state of the unthought” and the “pre-constructed,” some examples from academic discourse are discussed to foreground how a certain type of instrumental thinking is linked to market-oriented politics and how this shapes concepts in academic discourse as well. It is argued that the effects of the instrumental can be found on several levels in Translation Studies and that these levels are interrelated. These include the ways translation is understood and approached in practice by interaction partners involved in translation and interpreting processes, in the discourses on translation and interpretation in fields outside academia, and in scholarly work on translation.
On Mills' ‘Jung's Metaphysics’
Authors: Segal Robert A.
Published: June 2014

Despite his patient attempt to reconstruct Jung's metaphysics, Jon Mills fails to show that Jung was a metaphysician or even a philosopher of science and perhaps even a scientist. Mills seems to equate metaphysics with the postulation of immaterial entities – notably, archetypes. But on the one hand metaphysics can be materialist as well as dualist. On the other hand it is a speculative enterprise. A metaphysician would not simply announce the existence of immateriality but would seek to prove that immateriality fits the nature of reality as already known. Jung's metaphysics, which for him means sheer pronouncements, constitutes neither psychologism nor idealism, as Mills seems to agree. But Jung is not a Kantian, either. Jung should be treated as a great psychologist, but not as a thinker.
Innate lymphoid cells facilitate NK cell development through a lymphotoxin-mediated stromal microenvironment
Authors: Kim Tae-Jin , Upadhyay Vaibhav , Kumar Vinay , Lee Kyung-Mi , Fu Yang-Xin
Published: June 2014

Natural killer (NK) cell development relies on signals provided from the bone marrow (BM) microenvironment. It is thought that lymphotoxin (LT) α1β2 expressed by the NK cell lineage interacts with BM stromal cells to promote NK cell development. However, we now report that a small number of RORγt+ innate lymphoid cells (ILCs), and not CD3−NK1.1+ cells, express LT to drive NK development. Similar to LT−/− or RORγt−/− mice, the mice conditionally lacking LTα1β2 on RORγt+ ILCs experience a developmental arrest at the immature NK stages, between stages of NK development to the mature NK cell stage. This developmental block results in a functional deficiency in the clearance of NK-sensitive tumor cells. Reconstitution of Thy1+ ILCs from BM or purified RORγt+ ILCs from lamina propria lymphocytes into LT-deficient RORγt+ BM cultures rescues NK cell development. These data highlight a previously undiscovered role of RORγt+ ILCs for NK cell development and define LT from ILCs as an essential molecule for the stromal microenvironment supporting NK cell development.
Obstructions to weak decomposability for simplicial polytopes
Authors: Hähnle Nicolai , Klee Steven , Pilaud Vincent
Published: June 2014

Provan and Billera introduced notions of (weak) decomposability of simplicial complexes as a means of attempting to prove polynomial upper bounds on the diameter of the facet-ridge graph of a simplicial polytope. Recently, De Loera and Klee provided the first examples of simplicial polytopes that are not weakly vertex-decomposable. These polytopes are polar to certain simple transportation polytopes. In this paper, we refine their analysis to prove that these

d
d

-dimensional polytopes are not even weakly

O
(

d

)

O(\sqrt {d})

-decomposable. As a consequence, (weak) decomposability cannot be used to prove a polynomial version of the Hirsch Conjecture.
Sections of Calabi-Yau threefolds with K3 fibration
Authors: Li Zhiyuan
Published: June 2014

We study sections of a Calabi-Yau threefold fibered over a curve by K3 surfaces. We show that there exist infinitely many isolated sections on certain K3 fibered Calabi-Yau threefolds and that the group of algebraic

1
1

-cycles generated by these sections modulo algebraic equivalence is not finitely generated. We also give examples of K

3
3

surfaces over the function field

F
F

of a complex curve with Zariski dense

F
F

-rational points, whose geometric model is Calabi-Yau.
Localization for Riesz means of Fourier expansions
Authors: Colzani Leonardo , Gigante Giacomo , Vargas Ana
Published: June 2014

The classical Riemann localization principle states that if an integrable function of one variable vanishes in an open set, then its Fourier expansion converges to zero in this set. This principle does not immediately extend to several dimensions, and here we study the Hausdorff dimension of the sets of points where localization for Riesz means of Fourier expansions may fail.
Hunter, Cauchy rabbit, and optimal Kakeya sets
Authors: Babichenko Yakov , Peres Yuval , Peretz Ron , Sousi Perla , Winkler Peter
Published: June 2014

A planar set that contains a unit segment in every direction is called a Kakeya set. We relate these sets to a game of pursuit on a cycle

Z

n

\mathbb {Z}_n

. A hunter and a rabbit move on the nodes of

Z

n

\mathbb {Z}_n

without seeing each other. At each step, the hunter moves to a neighbouring vertex or stays in place, while the rabbit is free to jump to any node. Adler et al. (2003) provide strategies for hunter and rabbit that are optimal up to constant factors and achieve probability of capture in the first

n
n

steps of order

1

/

log
⁡
n

1/\log n

. We show these strategies yield a Kakeya set consisting of

4
n

4n

triangles with minimal area (up to constant), namely

Θ
(
1

/

log
⁡
n
)

\Theta (1/\log n)

. As far as we know, this is the first non-iterative construction of a boundary-optimal Kakeya set. Considering the continuum analog of the game yields a construction of a random Kakeya set from two independent standard Brownian motions

{
B
(
s
)
:
s
≥
0
}

\{B(s): s \ge 0\}

and

{
W
(
s
)
:
s
≥
0
}

\{W(s): s \ge 0\}

. Let

τ
t

:=
min
{
s
≥
0
:
B
(
s
)
=
t
}

\tau _t:=\min \{s \ge 0: B(s)=t\}

. Then

X
t

=
W
(

τ
t

)

X_t=W(\tau _t)

is a Cauchy process and

K
:=
{
(
a
,

X
t

+
a
t
)
:
a
,
t
∈
[
0
,
1
]
}

K:=\{(a,X_t+at) : a,t \in [0,1]\}

is a Kakeya set of zero area. The area of the

ε
\varepsilon

-neighbourhood of

K
K

is as small as possible, i.e., almost surely of order

Θ
(
1

/

|

log
⁡
ε

|

)

\Theta (1/|\log \varepsilon |)

.
A primality test for 𝐾𝑝ⁿ+1 numbers
Authors: Grau José , Oller-Marcén Antonio , Sadornil Daniel
Published: June 2014

In this paper we generalize the classical Proth’s theorem and the Miller-Rabin test for integers of the form

N
=
K

p
n

+
1

N=Kp^n+1

. For these families, we present variations on the classical Pocklington’s results and, in particular, a primality test whose computational complexity is

O
~

(

log
2

⁡
N
)

\widetilde {O}(\log ^2 N)

and, what is more important, that requires only one modular exponentiation modulo

N
N

similar to that of Fermat’s test.
Analytically pricing European-style options under the modified Black-Scholes equation with a spatial-fractional derivative
Authors: Chen Wenting , Xu Xiang , Zhu Song-ping
Published: June 2014

This paper investigates the option pricing under the FMLS (finite moment log stable) model, which can effectively capture the leptokurtic feature observed in many financial markets. However, under the FMLS model, the option price is governed by a modified Black-Scholes equation with a spatial-fractional derivative. In comparison with standard derivatives of integer order, the fractional-order derivatives are characterized by their “globalness”, i.e., the rate of change of a function near a point is affected by the property of the function defined in the entire domain of definition rather than just near the point itself. This has added an additional degree of difficulty not only when a purely numerical solution is sought but also when an analytical method is attempted. Despite this difficulty, we have managed to find an explicit closed-form analytical solution for European-style options after successfully solving the FPDE (fractional partial differential equation) derived from the FMLS model. After the validity of the put-call parity under the FMLS model is verified both financially and mathematically, we have also proposed an efficient numerical evaluation technique to facilitate the implementation of our formula so that it can be easily used in trading practice.
Random groups contain surface subgroups
Authors: Calegari Danny , Walker Alden
Published: June 2014

A random group contains many quasiconvex surface subgroups.
Examining Rowe and Kahn’s Concept of Successful Aging: Importance of Taking a Life Course Perspective
Authors: Stowe James D. , Cooney Teresa M.
Published: June 2014

Purpose of the Study:

This article critiques Rowe and Kahn’s conceptualization of successful aging using tenets of the life course perspective.

Design and Methods:

A review and synthesis of the literature on successful aging and studies that use a life course perspective.

Results:

We draw on life course principles that view development as a dynamic lifelong process, embedded in historical time and place, and influenced by the web of relationships individuals are linked to, as well as more distal social structural factors. This discussion questions the relatively static nature of Rowe and Kahn’s successful aging model, its emphasis on personal control over one’s later-life outcomes, and neglect of historical and cultural context, social relationships, and structural forces in influencing later-life functioning.

Implications:

Caution in using the model in its current formulation is needed, and we promote thinking about how successful aging can better align with micro- and macrolevel issues through utilization of a life course perspective.
Horizontal distributions of Dungeness crab (Cancer magister) and red rock crab (Cancer productus) larvae in the Strait of Georgia, British Columbia
Authors: Sorochan Kevin A. , Quijón Pedro A.
Published: June 2014

The supply of planktonic larvae to adult populations is an important contributor to the spatial and temporal variability of benthic marine organisms. The ability to predict spatial patterns of larvae and recruits from the physical and biological processes that facilitate dispersal is required in order to advise and evaluate conservation and fisheries management decisions. In the present study, the horizontal distribution of Dungeness crab (Cancer magister) and red rock crab (Cancer productus) zoeae was described from surveys conducted in the Strait of Georgia in the spring of 2009 and 2010. Processes that may be responsible for generating spatial variability of larvae were evaluated based on (i) horizontal overlap between larvae and water properties, (ii) spatial dependence of larvae and water properties, and (iii) changes in the dispersion of stage-specific distributions. Interspecific variability between horizontal patterns of the first and second larval stages was primarily attributed to differences in the distribution of larval release locations, which appeared to be restricted to the southern and central strait for C. magister. Potential effects of physical processes on larval distributions are also discussed.
Opportunities and challenges for time-resolved studies of protein structural dynamics at X-ray free-electron lasers
Authors: Neutze Richard
Published: June 2014

X-ray free-electron lasers (XFELs) are revolutionary X-ray sources. Their time structure, providing X-ray pulses of a few tens of femtoseconds in duration; and their extreme peak brilliance, delivering approximately 10
12
X-ray photons per pulse and facilitating sub-micrometre focusing, distinguish XFEL sources from synchrotron radiation. In this opinion piece, I argue that these properties of XFEL radiation will facilitate new discoveries in life science. I reason that time-resolved serial femtosecond crystallography and time-resolved wide angle X-ray scattering are promising areas of scientific investigation that will be advanced by XFEL capabilities, allowing new scientific questions to be addressed that are not accessible using established methods at storage ring facilities. These questions include visualizing ultrafast protein structural dynamics on the femtosecond to picosecond time-scale, as well as time-resolved diffraction studies of non-cyclic reactions. I argue that these emerging opportunities will stimulate a renaissance of interest in time-resolved structural biochemistry.
Coherent convergent-beam time-resolved X-ray diffraction
Authors: Spence John C. H. , Zatsepin Nadia A. , Li Chufeng
Published: June 2014

The use of coherent X-ray lasers for structural biology allows the use of nanometre diameter X-ray beams with large beam divergence. Their application to the structure analysis of protein nanocrystals and single particles raises new challenges and opportunities. We discuss the form of these coherent convergent-beam (CCB) hard X-ray diffraction patterns and their potential use for time-resolved crystallography, normally achieved by Laue (polychromatic) diffraction, for which the monochromatic laser radiation of a free-electron X-ray laser is unsuitable. We discuss the possibility of obtaining single-shot, angle-integrated rocking curves from CCB patterns, and the dependence of the resulting patterns on the focused beam coordinate when the beam diameter is larger or smaller than a nanocrystal, or smaller than one unit cell. We show how structure factor phase information is provided at overlapping interfering orders and how a common phase origin between different shots may be obtained. Their use in refinement of the phase-sensitive intensity between overlapping orders is suggested.
Deducing fast electron density changes in randomly orientated uncrystallized biomolecules in a pump–probe experiment
Authors: Pande K. , Schwander P. , Schmidt M. , Saldin D. K.
Published: June 2014

We propose a method for deducing time-resolved structural changes in uncrystallized biomolecules in solution. The method relies on measuring the angular correlations of the intensities, when averaged over a large number of diffraction patterns from randomly oriented biomolecules in solution in a liquid solvent. The experiment is somewhat like a pump–probe version of an experiment on small angle X-ray scattering, except that the data expected by the algorithm are not just the radial variation of the averaged intensities. The differences of these correlation functions as measured from a photoexcited and dark structure enable the direct calculation of the difference electron density with a knowledge of only the dark structure. We exploit a linear relation we derive between the difference in these correlation functions and the difference electron density, applicable for small structural changes.
‘Hit and run’ serial femtosecond crystallography of a membrane kinase in the lipid cubic phase
Authors: Caffrey Martin , Li Dianfan , Howe Nicole , Shah Syed T. A.
Published: June 2014

The lipid-based bicontinuous cubic mesophase is a nanoporous membrane mimetic with applications in areas that include medicine, personal care products, foods and the basic sciences. An application of particular note concerns it use as a medium in which to grow crystals of membrane proteins for structure determination by X-ray crystallography. At least two variations of the mesophase exist. One is the highly viscous cubic phase, which has well developed long-range order. The other so-called sponge phase is considerably more fluid and lacks long-range order. The sponge phase has recently been shown to be a convenient vehicle for delivering microcrystals of membrane proteins to an X-ray free-electron laser beam for serial femtosecond crystallography (SFX). Unfortunately, the sponge phase approach calls for large amounts of protein that are not always available in the case of membrane proteins. The cubic phase offers the advantage of requiring significantly less protein for SFX but comes with its own challenges. Here, we describe the physico-chemical bases for these challenges, solutions to them and prospects for future uses of lipidic mesophases in the SFX arena.
Streptobacillus hongkongensis sp. nov., isolated from patients with quinsy and septic arthritis, and emended descriptions of the genus Streptobacillus and Streptobacillus moniliformis
Authors: Woo Patrick C. Y. , Wu Alan K. L. , Tsang Chi-Ching , Leung Kit-Wah , Ngan Antonio H. Y. , Curreem Shirly O. T. , Lam Kwok-Wai , Chen Jonathan H. K. , Chan Jasper F. W. , Lau Susanna K. P.
Published: June 2014

Two bacterial strains, HKU33Tand HKU34, were isolated in Hong Kong from the pus aspirated from the right peritonsillar abscess of a patient with quinsy and the left elbow joint fluid of another patient with tophaceous gout and left elbow septic arthritis, respectively. The bacteria were Gram-stain-negative, non-motile, non-spore-forming, non-haemolytic pleomorphic bacilli. They grew best on Columbia agar with 5 % defibrinated sheep blood in an anaerobic environment or aerobic environment with 5 % CO2. They also grew on chocolate agar but not on MacConkey agar. They were catalase- and cytochrome oxidase-negative. They showed a unique profile of enzyme activities distinguishable from their closely related species. Phylogenetic analysis of the complete 16S rRNA gene, and partialgroEL,gyrBandrecAgene sequences showed the two isolates formed a distinct branch within the familyLeptotrichiaceae, being related most closely toStreptobacillus moniliformis. Hierarchical cluster analysis of mass spectra of whole-cell protein contents showed that strains HKU33Tand HKU34 were closely related to each other, but were distinct fromStreptobacillus moniliformis,Sneathia sanguinegensand ‘Leptotrichia amnionii’. The DNA G+C content of strain HKU33Twas 26.0±2.1 mol% (mean±sd;n = 3). DNA–DNA hybridization demonstrated ≤45.02 % DNA relatedness between the two isolates andStreptobacillus moniliformisCCUG 13453T. A novel species,Streptobacillus hongkongensissp. nov., is proposed to accommodate strains HKU33Tand HKU34, with HKU33T( = JCM 18691T = NCTC 13659T = DSM 26322T) designated the type strain. Emended descriptions of the genusStreptobacillusandStreptobacillus moniliformisare also given.
Polyethyleneimine and polyethyleneimine-based nanoparticles: novel bacterial and yeast biofilm inhibitors
Authors: Azevedo M. M. , Ramalho P. , Silva A. P. , Teixeira-Santos R. , Pina-Vaz C. , Rodrigues A. G.
Published: June 2014

Biofilms are commonly involved in medical device-related infections. The purpose of this study was to determine the antimicrobial and anti-biofilm activity of polyethyleneimine (PEI) and PEI-based nanoparticles (nanoPEI) against Staphylococcus aureus, Staphylococcus epidermidis, Acinetobacter baumannii and Candida albicans (clinical and ATCC strains), and to evaluate their effect upon biofilm formation on polyurethane (PUR)-like catheters. MICs and minimal lethal concentrations of PEI and nanoPEI were determined according to CLSI microdilution reference protocols. For PEI, the MIC value was 195.31 mg l−1 for all the bacteria and 48.83 mg l−1 for the yeast strains. For nanoPEI, the MIC value was 1250 mg l−1 for all the strains except A. baumannii, for which it was 2500 mg l−1. Biofilm formation was assessed with PUR-like catheter segments and biofilm metabolic activity was quantified by colorimetry with a tetrazolium reduction assay. Plasma membrane integrity and membrane potential were assessed by flow cytometry after staining microbial cells with a membrane-impermeable dye, propidium iodide, and a membrane-potential marker, DiBAC4(3). PEI inhibited growth of all microbial species; higher concentrations of nanoPEI were needed to inhibit growth of all species. Biofilm formation in the presence of anti-bacterial PEI activity was dose-dependent (except for S. epidermidis) and species-related. NanoPEI at 0.5×MIC and MIC significantly reduced the metabolic activity of biofilms of S. aureus, S. epidermidis and A. baumannii, whereas 2×MIC was required in order to inhibit biofilm metabolic activity.
Combination therapy with thioridazine and dicloxacillin combats meticillin-resistant Staphylococcus aureus infection in Caenorhabditis elegans
Authors: Poulsen Marianne Ø. , Schøler Lone , Nielsen Anette , Skov Marianne N. , Kolmos Hans Jørn , Kallipolitis Birgitte H. , Olsen Anders , Klitgaard Janne K.
Published: June 2014

The shortage of drugs active against meticillin-resistantStaphylococcus aureus(MRSA) is a growing clinical problem.In vitrostudies indicate that the phenothiazine thioridazine (TZ) might enhance the activity of the β-lactam antibiotic dicloxacillin (DCX) to a level where MRSA is killed, but experiments in simple animal models have not been performed. In the present study, we introducedCaenorhabditis elegansinfected byS. aureusas anin vivomodel to test the effect of TZ as a helper drug in combination with DCX. Because TZ is an anthelmintic, initial experiments were carried out to define the thresholds of toxicity, determined by larval development, and induction of stress-response markers. No measurable effects were seen at concentrations of less than 64 mg TZ l−1. Seven different MRSA strains were tested for pathogenicity againstC. elegans, and the most virulent strain (ATCC 33591) was selected for further analyses. In a final experiment, full-grownC. eleganswere exposed to the test strain for 3 days and subsequently treated with 8 mg DCX l−1and 8 mg TZ l−1for 2 days. This resulted in a 14-fold reduction in the intestinal MRSA load as compared with untreated controls. Each drug alone resulted in a two- to threefold reduction in MRSA load. In conclusion,C. eleganscan be used as a simple model to test synergy between DCX and TZ against MRSA. The previously demonstratedin vitrosynergy can be reproducedin vivo.
Sequence and expression divergence of an ancient duplication of the chaperonin groESEL operon in Vibrio species
Authors: Chowdhury Nityananda , Kingston Joseph J. , Whitaker W. Brian , Carpenter Megan R. , Cohen Analuisa , Boyd E. Fidelma
Published: June 2014

Heat-shock proteins are molecular chaperones essential for protein folding, degradation and trafficking. The human pathogen Vibrio vulnificus encodes a copy of the groESEL operon in both chromosomes and these genes share <80 % similarity with each other. Comparative genomic analysis was used to determine whether this duplication is prevalent among Vibrionaceae specifically or Gammaproteobacteria in general. Among the Vibrionaceae complete genome sequences in the database (31 species), seven Vibrio species contained a copy of groESEL in each chromosome, including the human pathogens Vibrio cholerae, Vibrio parahaemolyticus and V. vulnificus. Phylogenetic analysis of GroEL among the Gammaproteobacteria indicated that GroESEL-1 encoded in chromosome I was the ancestral copy and GroESEL-2 in chromosome II arose by an ancient gene duplication event. Interestingly, outside of the Vibrionaceae within the Gammaproteobacteria, groESEL chromosomal duplications were rare among the 296 genomes examined; only five additional species contained two or more copies. Examination of the expression pattern of groEL from V. vulnificus cells grown under different conditions revealed differential expression between the copies. The data demonstrate that groEL-1 was more highly expressed during growth in exponential phase than groEL-2 and a similar pattern was also found in both V. cholerae and V. parahaemolyticus. Overall these data suggest that retention of both copies of groESEL in Vibrio species may confer an evolutionary advantage.
Bluetongue virus without NS3/NS3a expression is not virulent and protects against virulent bluetongue virus challenge
Authors: Feenstra Femke , van Gennip René G. P. , Maris-Veldhuis Mieke , Verheij Eline , van Rijn Piet A.
Published: June 2014

Bluetongue is a disease in ruminants caused by the bluetongue virus (BTV), and is spread by Culicoides biting midges. Bluetongue outbreaks cause huge economic losses and death in sheep in several parts of the world. The most effective measure to control BTV is vaccination. However, both commercially available vaccines and recently developed vaccine candidates have several shortcomings. Therefore, we generated and tested next-generation vaccines for bluetongue based on the backbone of a laboratory-adapted strain of BTV-1, avirulent BTV-6 or virulent BTV-8. All vaccine candidates were serotyped with VP2 of BTV-8 and did not express NS3/NS3a non-structural proteins, due to induced deletions in the NS3/NS3a ORF. Sheep were vaccinated once with one of these vaccine candidates and were challenged with virulent BTV-8 3 weeks after vaccination. The NS3/NS3a knockout mutation caused complete avirulence for all three BTV backbones, including for virulent BTV-8, indicating that safety is associated with the NS3/NS3a knockout phenotype. Viraemia of vaccine virus was not detected using sensitive PCR diagnostics. Apparently, the vaccine viruses replicated only locally, which will minimize spread by the insect vector. In particular, the vaccine based on the BTV-6 backbone protected against disease and prevented viraemia of challenge virus, showing the efficacy of this vaccine candidate. The lack of NS3/NS3a expression potentially enables the differentiation of infected from vaccinated animals, which is important for monitoring virus spread in vaccinated livestock. The disabled infectious single-animal vaccine for bluetongue presented here is very promising and will be the subject of future studies.