bluuebunny/crossref_metadata_2025 huggingface dataset:
Determining the absorption tolerance of single chromophore photodiodes for machine vision
Authors: Jansen van Vuuren R. , Johnstone K. D. , Ratnasingam S. , Barcena H. , Deakin P. C. , Pandey A. K. , Burn P. L. , Collins S. , Samuel I. D. W.
Published: June 2010

Color information is much less useful to machine vision systems than to people because the spectrum of light illuminating a scene is unknown. For scenes illuminated by daylight, color information can be made significantly more useful to machine vision systems if the scene is imaged using sensors with a specifically chosen combination of spectral responses. In this paper we show that detectors with a full width at half maximum of up to 100 nm can give good color discrimination, and that conjugated dendrimer chromophores have the spectral properties required to allow machine vision systems to confidently use color information.
Direct observation of amophization in load rate dependent nanoindentation studies of crystalline Si
Authors: Das C. R. , Dhara S. , Jeng Yeau-Ren , Tsai Ping-Chi , Hsu H. C. , Raj Baldev , Bhaduri A. K. , Albert S. K. , Tyagi A. K. , Chen L. C. , Chen K. H.
Published: June 2010

Indentation at very low load rate showed region of constant volume with releasing load in crystalline (c-)Si, indicating a direct observation of liquidlike amorphous phase which is incompressible under pressure. Signature of amorphization is also confirmed from load dependent indentation study where increased amount of amorphized phase is made responsible for the increasing elastic recovery of the sample with increasing load. Ex situ Raman study confirmed the presence of amorphous phase at the center of indentation. The molecular dynamic simulation has been employed to demonstrate that the effect of indentation velocities has a direct influence on c-Si during nanoindentation processes.
Improved thermoelectric performance of organic thin-film elements utilizing a bilayer structure of pentacene and 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ)
Authors: Harada Kentaro , Sumino Mao , Adachi Chihaya , Tanaka Saburo , Miyazaki Koji
Published: June 2010

We demonstrate an improved thermoelectric performance of small molecular thin films fabricated by thermal deposition of pentacene as a p-type conduction layer. To enhance the performance, a bilayer structure composed of an intrinsic pentacene layer and an acceptor 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane layer is utilized as the prototype thermoelectric element. With the bilayer structure, the electrical conductivity reaches 0.43 S/cm, exhibiting a positive Seebeck coefficient of about 200 μV/K. We thus obtain a high power factor of 2.0 μW/mK2 with an optimized layer thickness.
Modeling and simulation of uniaxial strain effects in armchair graphene nanoribbon tunneling field effect transistors
Authors: Kang Jiahao , He Yu , Zhang Jinyu , Yu Xinxin , Guan Ximeng , Yu Zhiping
Published: June 2010

In this paper, we perform a modeling and simulation study on strained armchair graphene nanoribbon (AGNR). Two uniaxial strain models based on a tight binding method are compared with results from first-principles calculation. Tunneling field effect transistors (TFETs) with channels made of strained AGNR of different widths are modeled and simulated by a ballistic quantum transport model based on nonequilibrium Green’s function and nonparabolic effective mass approximation. Compared with TFETs with narrow AGNR, those with strained wide AGNR can achieve better device performance.
Continuous photocontrolled deformable membrane mirror
Authors: Bortolozzo U. , Bonora S. , Huignard J. P. , Residori S.
Published: June 2010

We present a deformable mirror that is composed by a metalized membrane with a monolithic nonpixelated photoconductive Bi12SiO20 substrate. The assembly constitutes a continuous photocontrolled deformable mirror and is driven through suitable light intensity distributions illuminating the photoconductive element. The continuous deformation of the reflective surface provides an all-optical and dynamical control of the incoming wave front, without spatial segmentation and with a deformation as large as a few microns.
Highly efficient acceleration and collimation of high-density plasma using laser-induced cavity pressure
Authors: Badziak J. , Borodziuk S. , Pisarczyk T. , Chodukowski T. , Krousky E. , Masek K. , Skala J. , Ullschmied J. , Rhee Yong-Joo
Published: June 2010

An efficient scheme of acceleration and collimation of dense plasma is proposed and examined. In the scheme, a target placed in a cavity coupled with a guiding channel is irradiated by a laser beam introduced into the cavity through a hole and accelerated along the channel by the pressure of the ablating plasma confined in the cavity. Using 1.315 μm, 0.3 ns laser pulse of energy up to 200 J and a thin CH target, it was shown that the energetic efficiency of acceleration in this scheme is an order of magnitude higher than in the case of conventional ablative acceleration.
Communications: A systematic method for locating transition structures of A+B→X type reactions
Authors: Maeda Satoshi , Morokuma Keiji
Published: June 2010

Search for transition structures (TSs) as first-order saddles is one of the most important tasks in theoretical study of chemical reaction. Although automated search has been established either by starting from a local minimum (MIN) or by connecting two MINs, there is no systematic method which can locate TSs of A+B→X(+Y) type reactions starting from separated reactants. We propose such an approach for the first time; it was demonstrated to work very well in the SN2, Diels–Alder, and Wittig reactions.
Now You Feel it, Now You Don't: How Robust is the Phenomenon of Illusory Tactile Experience?
Authors: McKenzie Kirsten J , Poliakoff Ellen , Brown Richard J , Lloyd Donna M
Published: June 2010

Recent studies have reported that in normal healthy individuals, the perception of illusory sensations in one modality can be induced by the presentation of a stimulus in another modality. These illusory sensations may arise from the activation of a tactile representation in memory induced by the non-target stimulus, in a process mirroring that thought to be responsible for many forms of medically unexplained symptoms. The reliability of illusory-touch reports was investigated here in two experiments with a novel perceptual paradigm designed to simulate the occurrence of somatoform symptoms in the laboratory. A concurrent light significantly increased the number of tactile stimuli reported, and resulted in a higher number of illusory-touch reports, while the modality of the trial start cue did not affect subsequent responses. In addition, a strong relationship was found between the rates of illusory sensations that participants produced in successive sessions, indicating that the tendency to report illusory sensations is a robust phenomenon.
The Function and Specificity of Sensitivity to Cues to Facial Identity: An Individual-Differences Approach
Authors: Mondloch Catherine J , Desjarlais Malinda
Published: June 2010

The expertise of adults in recognising the identity of individual faces has been attributed to their exquisite sensitivity to differences among faces in the spacing of features ( second-order relations). However, the reliability of individual differences and the extent to which this sensitivity predicts individuals' ability to recognise faces has not been tested directly. We administered two sets of tasks to adult females ( n = 31); the tests were separated by 2 to 11 days. Individual differences in sensitivity to the spacing of facial features were reliable across days and correlated with individual differences in sensitivity to the spacing of features (doors and windows) in houses, but did not predict accuracy when participants matched facial identity across changes in point of view. Individual differences in sensitivity to featural cues to facial identity were not reliable, likely because of ceiling effects. The function and specificity of sensitivity to the spacing of features is discussed.
Perceptual Compromise between Apparent and Veridical Motion Indices: The Unchained-Dots Illusion
Authors: Gori Simone , Giora Enrico , Stubbs D Alan
Published: June 2010

A new motion illusion based on dot-trajectory misperception is presented. The illusory effect can not be explained by the aperture problem unlike some previous illusions characterised by misperception of motion direction. We propose an explanation in terms of ‘perceptual compromise’ between an original type of apparent motion and the veridical motion. Several demonstrations are presented in support of that hypothesis.
Mesoscale model simulation of the meteorological conditions during the 2 June 2002 Double Trouble State Park wildfire
Authors: Charney Joseph J. , Keyser Daniel
Published: June 2010

On the morning of 2 June 2002, an abandoned campfire grew into a wildfire in the Double Trouble State Park in east-central New Jersey, USA. The wildfire burned 526 ha (1300 acres) and forced the closure of the Garden State Parkway for several hours due to dense smoke. In addition to the presence of dead and dry fuels due to a late spring frost prior to the wildfire, the meteorological conditions at the time of the wildfire were conducive to erratic fire behaviour and rapid fire growth. Observations indicate the occurrence of a substantial drop in relative humidity at the surface accompanied by an increase in wind speed in the vicinity of the wildfire during the late morning and early afternoon of 2 June. The surface drying and increase in wind speed are hypothesised to result from the downward transport of dry, high-momentum air from the middle troposphere occurring in conjunction with a deepening mixed layer. This hypothesis is addressed using a high-resolution mesoscale model simulation to document the structure and evolution of the planetary boundary layer and lower-tropospheric features associated with the arrival of dry, high-momentum air at the surface coincident with the sudden and dramatic growth of the wildfire.
Impacts of erosion control treatments on native vegetation recovery after severe wildfire in the Eastern Cascades, USA
Authors: Dodson Erich K. , Peterson David W. , Harrod Richy J.
Published: June 2010

Slope stabilisation treatments like mulching and seeding are used to increase soil cover and reduce runoff and erosion following severe wildfires, but may also retard native vegetation recovery. We evaluated the effects of seeding and fertilisation on the cover and richness of native and exotic plants and on individual plant species following the 2004 Pot Peak wildfire in Washington State, USA. We applied four seeding and three fertilisation treatments to experimental plots at eight burned sites in spring 2005 and surveyed vegetation during the first two growing seasons after fire. Seeding significantly reduced native non-seeded species richness and cover by the second year. Fertilisation increased native plant cover in both years, but did not affect plant species richness. Seeding and fertilisation significantly increased exotic cover, especially when applied in combination. However, exotic cover and richness were low and treatment effects were greatest in the first year. Seeding suppressed several native plant species, especially disturbance-adapted forbs. Fertilisation, in contrast, favoured several native understorey plant species but reduced tree regeneration. Seeding, even with native species, appears to interfere with the natural recovery of native vegetation whereas fertilisation increases total plant cover, primarily by facilitating native vegetation recovery.
Monte Carlo-based ensemble method for prediction of grassland fire spread
Authors: Cruz Miguel G.
Published: June 2010

The operational prediction of fire spread to support fire management operations relies on a deterministic approach where a single ‘best-guess’ forecast is produced from the best estimate of the environmental conditions driving the fire. Although fire can be considered a phenomenon of low predictability and the estimation of input conditions for fire behaviour models is fraught with uncertainty, no error component is associated with these forecasts. At best, users will derive an uncertainty bound to the model outputs based on their own personal experience. A simple ensemble method that considers the uncertainty in the estimation of model input values and Monte Carlo sampling was applied with a grassland fire-spread model to produce a probability density function of rate of spread. This probability density function was then used to describe the uncertainty in the fire behaviour prediction and to produce probability-based outputs. The method was applied to a grassland wildfire case study dataset. The ensemble method did not improve the general statistics describing model fit but provided complementary information describing the uncertainty associated with the predictions and a probabilistic output for the occurrence of threshold levels of fire behaviour.
Designing communicating colonies of biomimetic microcapsules
Authors: Kolmakov German V. , Yashin Victor V. , Levitan Steven P. , Balazs Anna C.
Published: June 2010

Using computational modeling, we design colonies of biomimetic microcapsules that exploit chemical mechanisms to communicate and alter their local environment. As a result, these synthetic objects can self-organize into various autonomously moving structures and exhibit ant-like tracking behavior. In the simulations, signaling microcapsules release agonist particles, whereas target microcapsules release antagonist particles and the permeabilities of both capsule types depend on the local particle concentration in the surrounding solution. Additionally, the released nanoscopic particles can bind to the underlying substrate and thereby create adhesion gradients that propel the microcapsules to move. Hydrodynamic interactions and the feedback mechanism provided by the dissolved particles are both necessary to achieve the collective dynamics exhibited by these colonies. Our model provides a platform for integrating both the spatial and temporal behavior of assemblies of “artificial cells,” and allows us to design a rich variety of structures capable of exhibiting complex, cooperative behavior. Due to the cell-like attributes of polymeric microcapsules and polymersomes, material systems are available for realizing our predictions.
High-throughput method for analyzing methylation of CpGs in targeted genomic regions
Authors: Nautiyal Shivani , Carlton Victoria E. H. , Lu Yontao , Ireland James S. , Flaucher Diane , Moorhead Martin , Gray Joe W. , Spellman Paul , Mindrinos Michael , Berg Paul , Faham Malek
Published: June 2010

A unique microarray-based method for determining the extent of DNA methylation has been developed. It relies on a selective enrichment of the regions to be assayed by target amplification by capture and ligation (mTACL). The assay is quantitatively accurate, relatively precise, and lends itself to high-throughput determination using nanogram amounts of DNA. The measurements using mTACLs are highly reproducible and in excellent agreement with those obtained by sequencing (
r
= 0.94). In the present work, the methylation status of >145,000 CpGs from 5,472 promoters in 221 samples was measured. The methylation levels of nearby CpGs are correlated, but the correlation falls off dramatically over several hundred base pairs. In some instances, nearby CpGs have very different levels of methylation. Comparison of normal and tumor samples indicates that in tumors, the promoter regions of genes involved in differentiation and signaling are preferentially hypermethylated, whereas those of housekeeping genes remain hypomethylated. mTACL is a platform for profiling the state of methylation of a large number of CpG in many samples in a cost-effective fashion, and is capable of scaling to much larger numbers of CpGs than those collected here.
Harnessing structure-activity relationship to engineer a cisplatin nanoparticle for enhanced antitumor efficacy
Authors: Paraskar Abhimanyu S. , Soni Shivani , Chin Kenneth T. , Chaudhuri Padmaparna , Muto Katherine W. , Berkowitz Julia , Handlogten Michael W. , Alves Nathan J. , Bilgicer Basar , Dinulescu Daniela M. , Mashelkar Raghunath A. , Sengupta Shiladitya
Published: June 2010

Cisplatin is a first line chemotherapy for most types of cancer. However, its use is dose-limited due to severe nephrotoxicity. Here we report the rational engineering of a novel nanoplatinate inspired by the mechanisms underlying cisplatin bioactivation. We engineered a novel polymer, glucosamine-functionalized polyisobutylene-maleic acid, where platinum (Pt) can be complexed to the monomeric units using a monocarboxylato and an O → Pt coordinate bond. We show that at a unique platinum to polymer ratio, this complex self-assembles into a nanoparticle, which releases cisplatin in a pH-dependent manner. The nanoparticles are rapidly internalized into the endolysosomal compartment of cancer cells, and exhibit an IC50 (4.25 ± 0.16 μM) comparable to that of free cisplatin (3.87 ± 0.37 μM), and superior to carboplatin (14.75 ± 0.38 μM). The nanoparticles exhibited significantly improved antitumor efficacy in terms of tumor growth delay in breast and lung cancers and tumor regression in a K-rasLSL/+/Ptenfl/flovarian cancer model. Furthermore, the nanoparticle treatment resulted in reduced systemic and nephrotoxicity, validated by decreased biodistribution of platinum to the kidney as quantified using inductively coupled plasma spectroscopy. Given the universal need for a better platinate, we anticipate this coupling of nanotechnology and structure-activity relationship to rationally reengineer cisplatin could have a major impact globally in the clinical treatment of cancer.
ZnSe/ZnTe(shell/shell) radial quantum-wire heterostructures: the excitonic properties
Authors: Bagheri Mehran
Published: June 2010

The ground-state characteristics of spatially indirect excitons trapped in radially heteronanostructured type-II band alignment ZnSe/ZnTe nanotubes as functions of the magnetic field for nanotubes with a radial size both smaller and larger than the effective Bohr radius are theoretically investigated. In the former case, dominated by the net kinetic energy of the electron and hole, the magnetic field modifies the exciton spectrum through the well-known Zeeman splitting, intra-orbital-state Aharonov–Bohm oscillations and inter-orbital-state crossovers occurring in very strong magnetic field strengths. However, in the latter case, dominated by the electron–hole Coulomb attraction, the magnetic field adjusts the exciton lines only by means of the Zeeman splitting and inter-orbital-state transitions happening in typical magnetic fields. As a result, the angular momentum transitions occurr at lower magnetic fields when the radial size of the nanotube is increased. Most importantly, another consequence is the substantially unusual exciton oscillator strength in such heteronanostructures. It is shown that when the exciton is optically active, due to the full cylindrical symmetry of the problem, the exciton oscillator strength shows undamped oscillations. This effect is associated with the periodic redistribution of the exciton density as the magnetic field is varied. Also, the magnitude of the magnetically induced excitonic persistent current is decreased with increasing radial size of the nanotube. This study may provide a platform to investigate new photonic quantum interference as well as polarization-sensitive photodetector and photovoltaic devices based on the Aharonov–Bohm effect.
The influence of magnetostatic interactions in exchange-coupled composite particles
Authors: Vokoun D , Beleggia M , De Graef M , Hou HC , Lai CH
Published: June 2010

Exchange-coupled composite (ECC) particles are the basic constituents of ECC magnetic recording media. We examine and compare two types of ECC particles: (i) core–shell structures, consisting of a hard-magnetic core and a coaxial soft-magnetic shell and (ii) conventional ECC particles, with a hard-magnetic core topped by a soft cylindrical element. The model we present describes the magnetic response of the two ECC particle types, taking into account all significant magnetic contributions to the energy landscape. Special emphasis is given to the magnetostatic (dipolar) interaction energy. We find that both the switching fields and the zero-field energy barrier depend strongly on the particle geometry. A comparison between the two types reveals that core–shell ECC particles are more effective in switching field reduction, while conventional ECC particles maintain a larger overall figure of merit.
Room temperature synthesis and one-dimensional self-assembly of interlaced Ni nanodiscs under magnetic field
Authors: Li Pengwei , Cui Yimin , Behan Gavin , Zhang Hongzhou , Wang Rongming
Published: June 2010

Uniform and aligned nickel nanochains with interlaced-nanodiscs structure were first synthesized by using a template-free magnetic-field-assisted method at room temperature. The interlaced-disc nanochains were composed of nanodiscs with diameters of ∼90 nm and thicknesses of ∼10 nm. An attachment process has been proposed to explain the observed growth of the nanodiscs. With concentration of the OH− increased, the morphology of the products transforms from star- to interlaced-nanodisc-like nanochains. Systematic magnetic measurements demonstrate that the well-aligned interlaced-nanodisc-like Ni nanochains have coercivity of about 300 Oe and effective anisotropy of about five times more than the bulk value.
Colloidal ZnO quantum dot-based, solution-processed transparent field-effect transistors
Authors: Ahn Joo-Seob , Lee Jong-Jin , Hyung Gun Woo , Kim Young Kwan , Yang Heesun
Published: June 2010

ZnO-based transistors were solution-processed using ∼3.6 nm sized ZnO quantum dots (QDs). Spin-deposited ZnO QD layer was annealed to remove QD capping organic molecules and to increase the connectivity of adjacent QDs. The resulting QD layer was highly transparent and crack free without any noticeable pores. 600 °C annealing of QD channel layer resulted in the highest electrical performances of bottom-gate QD-based transistors. A small quantity of Sn doping into the QD channel layer was found to be effective in further improving the electrical characteristics of the QD-based transistor, in particular exhibiting a higher field-effect mobility (0.282 cm2 V−1 s−1) by more than 4 factors than that of an undoped QD-based one. Finally, a fully transparent Sn-doped QD-based device was demonstrated by sputter deposition of Ga-doped ZnO as source–drain transparent electrodes and its electrical properties were evaluated.
Investigation of the effect of metastable atoms on mode transition in argon inductive discharge via a hybrid model
Authors: Zhao Shu-Xia , Wang You-Nian
Published: June 2010

By using an improved hybrid Monte Carlo/fluid model with the metastable solver and power deposition scheme, we investigate the dynamic characteristics of metastable atoms and their influences on plasma conditions during mode transition, and moreover explore its role in hysteresis by searching the nonlinear mechanism. The evolution behaviours of metastable atoms with power deposition at different pressures are traced. Besides, the effects of metastable atoms and multistep ionization on the variation of plasma parameters, e.g. electron density, temperature and energy distribution function, etc, during the transition are systematically examined. When cycling the inputted electrical parameters, coil current and voltages, hysteresis does not appear. The basic characteristic of plasma dynamics during mode transition is not significantly influenced by the presence of metastable atoms. Moreover, a linearly increasing slope of plasma density with the deposited power is observed and no evidence of nonlinear mechanisms is detected.
Distance-dependent plasma composition and ion energy in high power impulse magnetron sputtering
Authors: Ehiasarian Arutiun P , Andersson Joakim , Anders André
Published: June 2010

The plasma composition of high power impulse magnetron sputtering (HIPIMS) has been studied for titanium and chromium targets using a combined energy analyser and quadrupole mass spectrometer. Measurements were done at distances from 50 to 300 mm from the sputtering target. Ti and Cr are similar in atomic mass but have significantly different sputter yields, which gives interesting clues on the effect of the target on plasma generation and transport of atoms. The Ti and Cr HIPIMS plasmas operated at a peak target current density of ∼0.5 A cm−2. The measurements of the argon and metal ion content as well as the ion energy distribution functions showed that (1) singly and doubly charged ions were found for argon as well as for the target metal, (2) the majority of ions were singly charged argon for both metals at all distances investigated, (3) the Cr ion density was maintained to distances further from the target than Ti. Gas rarefaction was identified as a main factor promoting transport of metal ions, with the stronger effect observed for Cr, the material with higher sputter yield. Cr ions were found to displace a significant portion of the gas ions, whereas this was less evident in the Ti case. The observations indicate that the presence of metal vapour promotes charge exchange and reduces the electron temperature and thereby practically prevents the production of Ar2+ ions near the target. The content of higher charge states of metal ions depends on the probability of charge exchange with argon.
Modification of GaAs surface by low-current Townsend discharge
Authors: Gurevich E L , Kittel S , Hergenröder R , Astrov Yu A , Portsel L M , Lodygin A N , Tolmachev V A , Ankudinov A V
Published: June 2010

The influence of stationary spatially homogeneous Townsend discharge on the (1 0 0) surface of semi-insulating GaAs samples is studied. Samples exposed to both electrons and ions in a nitrogen discharge at a current density j = 60 µA cm−2 are studied by means of x-ray photoelectron spectroscopy, ellipsometry and atomic force microscopy. It is shown that an exposure to low-energy ions (<1 eV) changes the crystal structure of the semiconductor for a depth of up to 10–20 nm, although the stoichiometric composition does not change. The exposure to low-energy electrons (<10 eV) forms an oxide layer, which is 5–10 nm thick. Atomic force microscopy demonstrates that the change in the surface potential of the samples may exceed 100 mV, for both discharge polarities, while the surface roughness does not increase.
Can you tell the density of the watermelon from this photograph?
Authors: Foong See Kit , Lim Chim Chai
Published: June 2010

Based on a photograph, the density of a watermelon floating in a pail of water is estimated
with different levels of simplification—with and without consideration of refraction and
three-dimensional effects. The watermelon was approximated as a sphere. The results of the
theoretical estimations were verified experimentally.
Rotation distance, triangulations, and hyperbolic geometry
Authors: Sleator Daniel D. , Tarjan Robert E. , Thurston William P.
Published: June 2010

A rotation in a binary tree is a local restructuring that changes the tree into another tree. Rotations are useful in the design of tree-based data structures. The rotation distance between a pair of trees is the minimum number of rotations needed to convert one tree into the other. In this paper we establish a tight bound of

2
n
−
6

2n - 6

on the maximum rotation distance between two

n
n

-node trees for all large

n
n

. The hard and novel part of the proof is the lower bound, which makes use of volumetric arguments in hyperbolic

3
3

-space. Our proof also gives a tight bound on the minimum number of tetrahedra needed to dissect a polyhedron in the worst case and reveals connections among binary trees, triangulations, polyhedra, and hyperbolic geometry.
The least action principle and the related concept of generalized flows for incompressible perfect fluids
Authors: Brenier Yann
Published: June 2010

The link between the Euler equations of perfect incompressible flows and the Least Action Principle has been known for a long time [1]. Solutions can be considered as geodesic curves along the manifold of volume preserving mappings. Here the “shortest path problem” is investigated. Given two different volume preserving mappings at two different times, find, for the intermediate times, an incompressible flow map that minimizes the kinetic energy (or, more generally, the Action). In its classical formulation, this problem has been solved [7] only when the two different mappings are sufficiently close in some very strong sense. In this paper, a new framework is introduced, where generalized flows are defined, in the spirit of L. C. Young, as probability measures on the set of all possible trajectories in the physical space. Then the minimization problem is generalized as the “continuous linear programming” problem that is much easier to handle. The existence problem is completely solved in the case of the

d
d

-dimensional torus. It is also shown that under natural restrictions a classical solution to the Euler equations is the unique optimal flow in the generalized framework. Finally, a link is established with the concept of measure-valued solutions to the Euler equations [6], and an example is provided where the unique generalized solution can be explicitly computed and turns out to be genuinely probabilistic.
Hopf algebras up to homotopy
Authors: Anick David J.
Published: June 2010

Let

(
A
,
d
)

(A,d)

denote a free

r
r

-reduced differential graded

R
R

-algebra, where

R
R

is a commutative ring containing

n

−
1

{n^{ - 1}}

for

1
≤
n
>
p

1 \leq n > p

. Suppose a “diagonal”

ψ
:
A
→
A
⊗
A

\psi :A \to A \otimes A

exists which satisfies the Hopf algebra axioms, including cocommutativity and coassociativity, up to homotopy. We show that

(
A
,
d
)

(A,d)

must equal

U
(
L
,
δ
)

U(L,\delta )

for some free differential graded Lie algebra

(
L
,
δ
)

(L,\delta )

if

A
A

is generated as an

R
R

-algebra in dimensions below

r
p

rp

. As a consequence, the rational singular chain complex on a topological monoid is seen to be the enveloping algebra of a Lie algebra. We also deduce, for an

r
r

-connected CW complex

X
X

of dimension

≤
r
p

\leq rp

, that the Adams-Hilton model over

R
R

is an enveloping algebra and that

p
th

p\text {th}

powers vanish in

H
~

∗

(
Ω
X
;

Z

p

)

{\tilde H^ * }(\Omega X;{{\mathbf {Z}}_p})

.
Kategorie 𝒪, perverse Garben und Moduln über den Koinvarianten zur Weylgruppe
Authors: Soergel Wolfgang
Published: June 2010

We give a description of “the algebra of category

O

\mathcal {O}

” which is explicit enough to prove that the structure of the direct summands of

O

\mathcal {O}

depends only on the integral Weyl group and the singularity of the central character, as well as to establish a weak version of the duality conjectures of Beilinson and Ginsburg [BGi]. As a byproduct we describe the intersection cohomology of Schubert varieties as modules over global cohomology ring. These are certain indecomposable graded self-dual modules over the coinvariant algebra of the Weyl group, via the Borel picture for the global cohomology ring of a flag manifold. They play a central role in this article and should have an interesting future.
Euler’s “exemplum memorabile inductionis fallacis” and 𝑞-trinomial coefficients
Authors: Andrews George E.
Published: June 2010

The trinomial coefficients are defined centrally by
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="normal upper Sigma Subscript j equals negative m Superscript normal infinity Baseline left-parenthesis Subscript j Baseline Superscript m Baseline right-parenthesis Subscript 2 Baseline x Superscript j Baseline equals left-parenthesis 1 plus x plus x Superscript negative 1 Baseline right-parenthesis Superscript m">

Σ

j
=
−
m

∞

(
j
m

)
2

x
j

=

(
1
+
x
+

x

−
1

)
m

\Sigma _{j = - m}^\infty {(_j^m)_2}{x^j} = {(1 + x + {x^{ - 1}})^m}

. Euler observed that for

−
1
≤
m
≤
7

- 1 \leq m \leq 7

,
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="3 left-parenthesis Subscript 0 Baseline Superscript m plus 1 Baseline right-parenthesis Subscript 2 Baseline minus left-parenthesis Subscript 0 Baseline Superscript m plus 2 Baseline right-parenthesis Subscript 2 Baseline equals upper F Subscript m Baseline left-parenthesis upper F Subscript m Baseline plus 1 right-parenthesis">

3

(

0

m
+
1

)
2

−

(

0

m
+
2

)
2

=

F
m

(

F
m

+
1
)

3{(_{\,\;0}^{m + 1})_2} - {(_{\,\;0}^{m + 2})_2} = {F_m}({F_m} + 1)

, where

F
m

{F_m}

is the

m
m

th Fibonacci number. The assertion is false for

m
>
7

m > 7

. We prove general identities—one of which reduces to Euler’s assertion for

m
≤
7

m \leq 7

. Our main object is to analyze

q
q

-analogs extending Euler’s observation. Among other things we are led to finite versions of dissections of the Rogers-Ramanujan identities into even and odd parts.
Common range of co-analytic Toeplitz operators
Authors: McCarthy John E.
Published: June 2010

We characterise the intersection of the ranges of all co-analytic Toeplitz operators, by considering this set as the dual space of the Smirnov class in a certain topology.
Adiabatic limits, nonmultiplicativity of signature, and Leray spectral sequence
Authors: Dai Xianzhe
Published: June 2010

We first prove an adiabatic limit formula for the

η
\eta

-invariant of a Dirac operator, generalizing the recent work of J.-M. Bismut and J. Cheeger. An essential part of the proof is the study of the spectrum of the Dirac operator in the adiabatic limit. A new contribution arises in the adiabatic limit formula, in the form of a global term coming from the (asymptotically) very small eigenvalues. We then proceed to show that, for the signature operator, these very small eigenvalues have a purely topological significance. In fact, we show that the Leray spectral sequence can be recast in terms of these very small eigenvalues. This leads to a refined adiabatic limit formula for the signature operator where the global term is identified with a topological invariant, the signature of a certain bilinear form arising from the Leray spectral sequence. As an interesting application, we give intrinsic characterization of the non-multiplicativity of signature.
A partition theorem for pairs of finite sets
Authors: Jech Thomas , Shelah Saharon
Published: June 2010

Every partition of

[

[

ω
1

]

>
ω

]
2

{[{[{\omega _1}]^{ > \omega }}]^2}

into finitely many pieces has a cofinal homogeneous set. Furthermore, it is consistent that every directed partially ordered set satisfies the partition property if and only if it has finite character.
Combinatorial stratification of complex arrangements
Authors: Björner Anders , Ziegler Günter M.
Published: June 2010

We present a method for discretizing complex hyperplane arrangements by encoding their topology into a finite partially ordered set of “sign vectors.” This is used in the following ways: (1) A general method is given for constructing regular cell complexes having the homotopy type of the complement of the arrangement. (2) For the case of complexified arrangements this specializes to the construction of Salvetti [S]. We study the combinatorial structure of complexified arrangements and the Salvetti complex in some detail. (3) This general method simultaneously produces cell decompositions of the singularity link. This link is shown to have the homotopy type of a wedge of spheres for arrangements in

C

d

,

d
≥
4

{\mathbb {C}^d},\;d \geq 4

. (4) The homology of the link and the cohomology of the complement are computed in terms of explicit bases, which are matched by Alexander duality. This gives a new, more elementary, and more generally valid proof for the Brieskorn-Orlik-Solomon theorem and some related results. (5) Our setup leads to a more general notion of “

2
2

-pseudoarrangements,” which can be thought of as topologically deformed complex arrangements (retaining only the essential topological and combinatorial structure). We show that all of the above remains true in this generality, except for the sign patterns of the Orlik-Solomon relations.
Flots d’Anosov à distributions stable et instable différentiables
Authors: Benoist Yves , Foulon Patrick , Labourie François
Published: June 2010

We describe which Anosov flows on compact manifolds have

C
∞

{C^\infty }

stable and unstable distributions and a contact canonical

1
1

-form: up to finite coverings and up to a

C
∞

{C^\infty }

change of parameters, each of them is isomorphic to the geodesic flow on (the unit tangent bundle of) a compact locally symmetric space of strictly negative curvature.
Perturbation theory for the Laplacian on automorphic functions
Authors: Phillips R. , Sarnak P.
Published: June 2010

Let

Γ
⊂

PSL(2, 

R

)

\Gamma \subset {\text {PSL(2, }}\mathbb {R}{\text {)}}

be a discrete subgroup with quotient

Γ
∖
H

\Gamma \backslash H

of finite volume but not compact. The spectrum of the Laplacian on

L
2

{L^2}

automorphic functions is unstable under perturbations; however, it becomes much more manageable when the scattering frequencies are adjoined (with multiplicity equal to the order of the pole of the determinant of the scattering matrix at these points). This augmented set shows up in a natural way in a one-sided version of the Selberg trace formula and is the actual spectrum of the generator of a cut-off wave equation. Applying standard perturbation theory to this operator, it is proved that the augmented spectrum is real analytic in Teichmüller space. The same operator is used to derive Fermi’s Golden Rule in this setting. It turns out that the proper multiplicity to be attached to the Laplacian eigenvalue at

1
4

\frac {1}{4}

is twice the dimension of cusp forms plus

μ
=

 tr

[
Φ

 + 

I
]

/2

\mu = {\text { tr}}[\Phi {\text { + }}I]{\text {/2}}

; here

Φ
\Phi

denotes the scattering matrix at this point. It is shown that the generic value of

μ
\mu

in the Teichmüller space of the once punctured torus and the six-times punctured sphere is zero. This is also true of the

χ
\chi

-twisted spectral problem, where

χ
\chi

is a character for

Γ
\Gamma

.
Subdivisions and local ℎ-vectors
Authors: Stanley Richard P.
Published: June 2010

In Part I a general theory of

f
f

-vectors of simplicial subdivisions (or triangulations) of simplicial complexes is developed, based on the concept of local

h
h

-vector. As an application, we prove that the

h
h

-vector of a Cohen-Macaulay complex increases under “quasi-geometric” subdivision, thus establishing a special case of a conjecture of Kalai and this author. Techniques include commutative algebra, homological algebra, and the intersection homology of toric varieties. In Part II we extend the work of Part I to more general situations. First a formal generalization of subdivision is given based on incidence algebras. Special cases are then developed, in particular one based on subdivisions of Eulerian posets and involving generalized

h
h

-vectors. Other cases deal with Kazhdan-Lusztig polynomials, Ehrhart polynomials, and a

q
q

-analogue of Eulerian posets. Many applications and examples are given throughout.
Regulation of Genotoxic Stress Response by Homeodomain-interacting Protein Kinase 2 through Phosphorylation of Cyclic AMP Response Element-binding Protein at Serine 271
Authors: Sakamoto Kensuke , Huang Bo-Wen , Iwasaki Kenta , Hailemariam Kiros , Ninomiya-Tsuji Jun , Tsuji Yoshiaki
Published: June 2010

CREB (cyclic AMP response element-binding protein) is a stimulus-induced transcription factor that plays pivotal roles in cell survival and proliferation. The transactivation function of CREB is primarily regulated through Ser-133 phosphorylation by cAMP-dependent protein kinase A (PKA) and related kinases. Here we found that homeodomain-interacting protein kinase 2 (HIPK2), a DNA-damage responsive nuclear kinase, is a new CREB kinase for phosphorylation at Ser-271 but not Ser-133, and activates CREB transactivation function including brain-derived neurotrophic factor (BDNF) mRNA expression. Ser-271 to Glu-271 substitution potentiated the CREB transactivation function. ChIP assays in SH-SY5Y neuroblastoma cells demonstrated that CREB Ser-271 phosphorylation by HIPK2 increased recruitment of a transcriptional coactivator CBP (CREB binding protein) without modulation of CREB binding to the BDNF CRE sequence. HIPK2−/− MEF cells were more susceptible to apoptosis induced by etoposide, a DNA-damaging agent, than HIPK2+/+ cells. Etoposide activated CRE-dependent transcription in HIPK2+/+ MEF cells but not in HIPK2−/− cells. HIPK2 knockdown in SH-SY5Y cells decreased etoposide-induced BDNF mRNA expression. These results demonstrate that HIPK2 is a new CREB kinase that regulates CREB-dependent transcription in genotoxic stress.
Overlapping Roles ofDrosophilaDrak and Rok Kinases in Epithelial Tissue Morphogenesis
Authors: Neubueser Dagmar , Hipfner David R.
Published: June 2010

Dynamic regulation of cytoskeletal contractility through phosphorylation of the nonmuscle Myosin-II regulatory light chain (MRLC) provides an essential source of tension for shaping epithelial tissues. Rho GTPase and its effector kinase ROCK have been implicated in regulating MRLC phosphorylation in vivo, but evidence suggests that other mechanisms must be involved. Here, we report the identification of a single Drosophila homologue of the Death-associated protein kinase (DAPK) family, called Drak, as a regulator of MRLC phosphorylation. Based on analysis of null mutants, we find that Drak broadly promotes proper morphogenesis of epithelial tissues during development. Drak activity is largely redundant with that of the Drosophila ROCK orthologue, Rok, such that it is essential only when Rok levels are reduced. We demonstrate that these two kinases synergistically promote phosphorylation of Spaghetti squash (Sqh), the Drosophila MRLC orthologue, in vivo. The lethality of drak/rok mutants can be rescued by restoring Sqh activity, indicating that Sqh is the critical common effector of these two kinases. These results provide the first evidence that DAPK family kinases regulate actin dynamics in vivo and identify Drak as a novel component of the signaling networks that shape epithelial tissues.
Average Crop Revenue Election: A Revenue‐Based Alternative to Price‐Based Commodity Payment Programs
Authors: Cooper Joseph C.
Published: June 2010

This article develops a stochastic model of the Average Crop Revenue Election (ACRE) program, which offers revenue‐based commodity payments under the 2008 Farm Act. Our analysis shows that adding ACRE revenue payments to gross revenue reduces downside revenue risk for corn, wheat, and soybean farmers in 2009 on average by 16%, 21%, and 23%, respectively. Results indicate that farms with higher expected yields and lower variance of yields tend to benefit the most from ACRE. Integrating federal crop insurance with ACRE lowers insurance premiums from 10% to 40%, depending on the crop and location.
Stated and Revealed Preferences for Organic and Cloned Milk: Combining Choice Experiment and Scanner Data
Authors: Brooks Kathleen , Lusk Jayson L.
Published: June 2010

The U.S. Food and Drug Administration's recent announcement that milk from cloned cows is as safe to drink as that from conventionally bred cows prompted interest among farmers, food retailers, and regulators in the market impacts of the introduction of milk from clones. Because milk from cloned animals is not currently labeled in the market, we utilized a stated preference experiment to determine consumer preferences for the attribute, but also sought to determine whether the survey‐based choices were consistent with people's revealed preferences given by scanner data. Our analysis indicates that a pooled model combining stated and revealed preference data exhibits overall better out‐of‐sample prediction performance than either data set used alone. Results from the pooled model indicate that consumers are willing to pay large premiums to avoid milk from cloned cows—an amount that is over three times that for organic or rBST‐free milk. The results are used to calculate the value of a mandatory labeling program.
Hormonal correlates of individual quality in a long-lived bird: a test of the ‘corticosterone–fitness hypothesis’
Authors: Angelier Frédéric , Wingfield John C. , Weimerskirch Henri , Chastel Olivier
Published: June 2010

Measuring individual quality in vertebrates is difficult. Focusing on allostasis mechanisms may be useful because they are functionally involved in the ability of an individual to survive and reproduce in its environment. Thus, a rise in stress hormones levels (corticosterone) occurs when an organism has to cope with challenging environmental conditions. This has recently led to the proposal of the ‘cort–fitness hypothesis’, which suggests that elevated baseline corticosterone levels should be found in individuals of poor quality that have difficulty coping with their environment. We tested this hypothesis by comparing an integrative measure of individual quality to baseline corticosterone in black-browed albatrosses (
Thalassarche melanophrys
). We found that individual baseline corticosterone levels were related to individual quality and highly repeatable from one breeding season to the next. Importantly, this relationship was found in males, but not in females. Therefore, we suggest that the relationship between quality and baseline corticosterone levels may depend on the environmental and energetic constraints that individuals have to cope with.
Qualitative assessment of the diet of European eel larvae in the Sargasso Sea resolved by DNA barcoding
Authors: Riemann Lasse , Alfredsson Hanna , Hansen Michael M. , Als Thomas D. , Nielsen Torkel G. , Munk Peter , Aarestrup Kim , Maes Gregory E. , Sparholt Henrik , Petersen Michael I. , Bachler Mirjam , Castonguay Martin
Published: June 2010

European eels (Anguilla anguilla) undertake spawning migrations of more than 5000 km from continental Europe and North Africa to frontal zones in the Sargasso Sea. Subsequently, the larval offspring are advected by large-scale eastward ocean currents towards continental waters. However, the Sargasso Sea is oligotrophic, with generally low plankton biomass, and the feeding biology of eel larvae has so far remained a mystery, hampering understanding of this peculiar life history. DNA barcoding of gut contents of 61 genetically identifiedA. anguillalarvae caught in the Sargasso Sea showed that even the smallest larvae feed on a striking variety of plankton organisms, and that gelatinous zooplankton is of fundamental dietary importance. Hence, the specific plankton composition seems essential for eel larval feeding and growth, suggesting a linkage between eel survival and regional plankton productivity. These novel insights into the prey of Atlantic eels may furthermore facilitate eel larval rearing in aquaculture, which ultimately may replace the unsustainable use of wild-caught glass eels.
Favouritism in the motor system: social interaction modulates action simulation
Authors: Kourtis Dimitrios , Sebanz Natalie , Knoblich Günther
Published: June 2010

The ability to anticipate others' actions is crucial for social interaction. It has been shown that this ability relies on motor areas of the human brain that are not only active during action execution and action observation, but also during anticipation of another person's action. Recording electroencephalograms during a triadic social interaction, we assessed whether activation of motor areas pertaining to the human mirror-neuron system prior to action observation depends on the social relationship between the actor and the observer. Anticipatory motor activation was stronger when participants expected an interaction partner to perform a particular action than when they anticipated that the same action would be performed by a third person they did not interact with. These results demonstrate that social interaction modulates action simulation.