bluuebunny/crossref_metadata_2025 huggingface dataset:
Bcl6 Controls the Th2 Inflammatory Activity of Regulatory T Cells by Repressing Gata3 Function
Authors: Sawant Deepali V. , Sehra Sarita , Nguyen Evelyn T. , Jadhav Rohit , Englert Kate , Shinnakasu Ryo , Hangoc Giao , Broxmeyer Hal E. , Nakayama Toshinori , Perumal Narayanan B. , Kaplan Mark H. , Dent Alexander L.
Published: October 2012

The transcriptional repressor Bcl6 is a critical arbiter of Th cell fate, promoting the follicular Th lineage while repressing other Th cell lineages. Bcl6-deficient (Bcl6−/−) mice develop a spontaneous and severe Th2-type inflammatory disease, thus warranting assessment of Bcl6 in regulatory T cell (Treg) function. Bcl6−/− Tregs were competent at suppressing T cell proliferation in vitro and Th1-type colitogenic T cell responses in vivo. In contrast, Bcl6−/− Tregs strongly exacerbated lung inflammation in a model of allergic airway disease and promoted higher Th2 responses, including systemic upregulation of microRNA-21. Further, Bcl6−/− Tregs were selectively impaired at controlling Th2 responses, but not Th1 and Th17 responses, in mixed chimeras of Bcl6−/− bone marrow with Foxp3−/− bone marrow. Bcl6−/− Tregs displayed increased levels of the Th2 transcription factor Gata3 and other Th2 and Treg genes. Bcl6 potently repressed Gata3 transcriptional transactivation, providing a mechanism for the increased expression of Th2 genes by Bcl6−/− Tregs. Gata3 has a critical role in regulating Foxp3 expression and functional fitness of Tregs; however, the signal that regulates Gata3 and restricts its transactivation of Th2 cytokines in Tregs has remained unexplored. Our results identify Bcl6 as an essential transcription factor regulating Gata3 activity in Tregs. Thus, Bcl6 represents a crucial regulatory layer in the Treg functional program that is required for specific suppression of Gata3 and Th2 effector responses by Tregs.
Prediction of Brownout Inception Beneath a Full-Scale Helicopter Downwash
Authors: Jasion Gregory , Shrimpton John
Published: October 2012

Dust entrained by low flying helicopters leads to the degraded visual environment, brownout. Particle inception is a critical stage in the development of the dust cloud. Here, near-wall Lagrangian particle forces are considered through analyzing an approximate time-averaged full-scale
rotor flow. This simplified flow does not attempt to predict brownout, instead it provides scales and velocity data in the near-wall region, compares the role of particle-fluid forces, and provides a foundation for Lagrangian entrainment models. The analysis shows that three characteristic
particle sizes are exposed to different physics in different boundary layer zones, a function of the distance from the helicopter. Drag is the dominant aerodynamic force, cohesion is large for small particles, but wall-bounded lift is sufficient to entrain medium-sized particles. A complementary
analytical prediction of tip vortices found that both large-scale inviscid features and small-scale viscous features of the boundary layer are significant.
Emergency surgical management of traumatic superior sagittal sinus injury: An unusual case
Authors: Mishra Sudhansu , Das Srikant , Behera Sanjay , Panigrahi Souvagya
Published: October 2012

Head injuries following fall of heavy objects are not very uncommon in developing countries. However, compound depressed skull fracture with superior sagittal sinus (SSS) laceration caused by a flying asbestos fragment in a stormy afternoon is an unusual mode of head injury. We report such an unusual case of compound depressed skull fracture by an asbestos fragment injuring the middle third of SSS and its successful surgical management in a 14-year-old child. The role of computed tomography (CT) scan of head with 3D reconstruction is highlighted. Early steps taken in this case to check the profuse bleeding, which helped save the life of this boy is interesting to note.
Smooth (non)rigidity of cusp-decomposable manifolds
Authors: Nguyên Phan T. Tâm
Published: October 2012

We define
cusp-decomposable
manifolds and prove smooth rigidity within this class of manifolds. These manifolds generally do not admit a nonpositively curved metric but can be decomposed into pieces that are diffeomorphic to finite-volume, locally symmetric, negatively curved manifolds with cusps. We prove that the group of outer automorphisms of the fundamental group of such manifolds contains a free abelian normal subgroup whose elements are induced by diffeomorphisms that are analogous to Dehn twists in surface topology. For the case where the decomposition is finite, the group of outer automorphisms of the fundamental group is an extension of a finitely generated free abelian group by a finite group. We also prove that the outer automorphism group can be realized by a group of diffeomorphisms of the manifold.
Local metric properties and regular stratifications of $p$-adic definable sets
Authors: Cluckers Raf , Comte Georges , Loeser François
Published: October 2012

We study the geometry of germs of definable (semialgebraic or subanalytic) sets over a

p

-adic field from the metric, differential and measure geometric point of view. We prove that the local density of such sets at each of their points does exist. We then introduce the notion of distinguished tangent cone with respect to some open subgroup with finite index in the multiplicative group of our field and show, as it is the case in the real setting, that, up to some multiplicities, the local density may be computed on this distinguished tangent cone. We also prove that these distinguished tangent cones stabilize for small enough subgroups. We finally obtain the

p

-adic counterpart of the Cauchy–Crofton formula for the density. To prove these results we use the Lipschitz decomposition of definable

p

-adic sets of [5] and prove here the genericity of the regularity conditions for stratification such as

(w_f)

,

(w)

,

(a_f)

,

(b)

and

(a)

conditions.
The structure of a local embedding and Chern classes of weighted blow-ups
Authors: Mustaţă Anca M. , Mustaţă Andrei
Published: October 2012

For a proper local embedding between two Deligne–Mumford stacks

Y

and

X

, we find, under certain mild conditions, a new (possibly non-separated) Deligne–Mumford stack

X'

, with an etale, surjective and universally closed map to the target

X

, and whose fiber product with the image of the local embedding is a finite union of stacks with corresponding etale, surjective and universally closed maps to

Y

. Moreover, a natural set of weights on the substacks of

X'

allows the construction of a universally closed push-forward, and thus a comparison between the Chow groups of

X'

and

X

. We apply the construction above to the computation of the Chern classes of a weighted blow-up along a regular local embedding via deformation to a weighted normal cone and localization. We describe the stack

X'

in the case when

X

is the moduli space of stable maps with local embeddings at the boundary. We apply the methods above to find the Chern classes of the stable map spaces.
On a new normalization for tractor covariant derivatives
Authors: Hammerl Matthias , Somberg Petr , Souček Vladimír , Šilhan Josef
Published: October 2012

A regular normal parabolic geometry of type

G/P

on a manifold

M

gives rise to sequences

D_i

of invariant differential operators, known as the curved version of the BGG resolution. These sequences are constructed from the normal covariant derivative

\nabla^\omega

on the corresponding tractor bundle

V,

where

\omega

is the normal Cartan connection. The first operator

D_0

in the sequence is overdetermined and it is well known that

\nabla^\omega

yields the prolongation of this operator in the homogeneous case

M = G/P

. Our first main result is the curved version of such a prolongation. This requires a new normalization of the tractor covariant derivative on

V

. Moreover, we obtain an analogue for higher operators

D_i

. In that case one needs to modify the exterior covariant derivative

d^{\nabla^\omega}

by differential terms. Finally we demonstrate these results on simple examples in projective, conformal and Grassmannian geometry. Our approach is based on standard techniques of the BGG machinery.
Finite-energy sign-changing solutions with dihedral symmetry for the stationary nonlinear Schrödinger equation
Authors: Musso Monica , Pacard Frank , Wei Juncheng
Published: October 2012

We address the problem of the existence of finite energy solitary waves for nonlinear Klein-Gordon or Schrödinger type equations

\Delta u - u + f(u) =0

in

\mathbb R^N

,

u \in H^1 (\mathbb R^N)

, where

N\geq 2

. Under natural conditions on the nonlinearity

f

, we prove the existence of
infinitely many nonradial solutions
in any dimension

N \geq 2

. Our result complements earlier works of Bartsch and Willem (

N=4

or

N \geq 6

) and Lorca-Ubilla (

N=5

) where solutions invariant under the action of

O(2) \times O(N-2)

are constructed. In contrast, the solutions we construct are invariant under the action of

D_k \times O(N-2)

where

D_k \subset O(2)

denotes the dihedral group of rotations and reflexions leaving a regular planar polygon with

k

sides invariant, for some integer

k\geq 7

, but they are not invariant under the action of

O(2) \times O(N-2)

.
$\mathcal L$-invariants and Darmon cycles attached to modular forms
Authors: Rotger Victor , Seveso Marco Adamo
Published: October 2012

Let

f

be a modular eigenform of even weight

k\geq 2

and new at a prime

p

dividing exactly the level with respect to an indefinite quaternion algebra. The theory of Fontaine-Mazur allows to attach to

f

a monodromy module

\mathbf{D}^{FM}_f

and an

\mathcal{L}

-invariant

\mathcal{L}^{FM}_f

. The first goal of this paper is building a suitable

p

-adic integration theory that allows us to construct a new monodromy module

\mathbf{D}_f

and

{\mathcal{L}}

-invariant

{\mathcal{L}}_f

, in the spirit of Darmon. The two monodromy modules are isomorphic, and in particular the two

{\mathcal{L}}

-invariants are equal.Let

K

be a real quadratic field and assume the sign of the functional equation of the

L

-series of

f

over

K

is

-1

. The Bloch-Beilinson conjectures suggest that there should be a supply of elements in the Selmer group of the motive attached to

f

over the tower of narrow ring class fields of

K

. Generalizing work of Darmon for

k=2

, we give a construction of local cohomology classes which we expect to arise from global classes and satisfy an explicit reciprocity law, accounting for the above prediction.
Normalization of the 1-stratum of the moduli space of stable curves
Authors: Edidin Dan , Fulghesu Damiano
Published: October 2012

Let

\mathcal{M}_g(\Gamma)

be the stack of stable curves of genus

g

with a given dual graph

\Gamma

and let

\overline{\mathcal{M}}_g(\Gamma)

be its closure in

\overline{\mathcal{M}}_g

. We consider the normalization of

\overline{\mathcal{M}}_g(\Gamma)

in order to classify the residual orbifolds of the normalizations of the irreducible components of the locus in

\overline{\mathcal{M}}_g

corresponding to curves with at least

3g - 4

nodes.
Equilibrium states and SRB-like measures of $C^1$-expanding maps of the circle
Authors: Catsigeras Eleonora , Enrich Heber
Published: October 2012

For any

C^1

-expanding map

f

of the circle we study the equilibrium states for the potential

\psi=-\log |f'|

. We formulate a

C^1

generalization of Pesin’s Entropy Formula that holds for all the Sinai–Ruelle–Bowen (SRB) measures if they exist, and for all the (necessarily existing) SRB-like measures. In the

C^1

-generic case Pesin’s Entropy Formula holds for a unique SRB measure which is not absolutely continuous with respect to Lebesgue. The result also stands in the non-generic case for which no SRB measure exists.
The classical solvability of the contact angle problem for generalized equations of mean curvature type
Authors: Druet Pierre-Étienne
Published: October 2012

Mean curvature equations of general quasilinear type in connection with contact-angle boundary conditions are considered in this paper. We investigate the existence, uniqueness and continuous dependence of the solution in classical function spaces. On the one hand, a survey of techniques and ideas developed in the 1970s and 1980s, mainly by Uraltseva, is presented. On the other hand, extensions of these results are also proposed: we formulate growth conditions for the general dependence of the potential on the

x_{N+1}

-variable, and we extend the existence and uniqueness statements to this case. Moreover, the regularity assumptions on the right-hand side are relaxed, and alternative proofs for the higher-order estimates and the existence result are provided.
General Boundary Stabilization of Memory-Type Thermoelasticity with Second Sound
Authors: Messaoudi Salim A. , Al-Shehri Aisha
Published: October 2012

In this paper we consider an

n

-dimensional system of visco-thermoelasticity with second sound, where a viscoelastic dissipation is acting on a part of the boundary. We prove some decay results for solutions with specific regular initial data. In this regard, polynomial and general decay results are established.
Spectral Gaps for Self-Adjoint Second Order Operators
Authors: Borisov Denis , Veselić Ivan
Published: October 2012

We consider a second order self-adjoint operator in a domain which can be bounded or unbounded. The boundary is partitioned into two parts with Dirichlet boundary condition on one of them, and Neumann condition on the other. We assume that the potential part of this operator is non-negative. We add a localized perturbation assuming that it produces two negative isolated eigenvalues being the two lowest spectral values of the resulting perturbed operator. The main result is a lower bound on the gap between these two eigenvalues. It is given explicitly in terms of the geometric properties of the domain and the coefficients of the perturbed operator. We apply this estimate to several asymptotic regimes studying its dependence on various parameters. We discuss specific examples of operators to which the bounds can be applied.
Partner attachment to institutional logics: The influence of congruence and divergence
Authors: Napshin Stuart A , Azadegan Arash
Published: October 2012

Partnerships are increasingly important to firm product innovation. They also increasingly involve parties that are attached to different institutional logics. We examine the effect of firm and partner attachments to the same and different institutional logics. Findings suggest that when partners are attached to the same institutional logic, new product development performance is positively influenced. However, when partners are attached to different institutional logics, new product development is negatively influenced. When controlling for attachment to different institutional logics, partnerships with private companies are more beneficial than partnerships with government research institutions.
Investigating sources of gaseous oxidized mercury in dry deposition at three sites across Florida, USA
Authors: Sexauer Gustin M. , Weiss-Penzias P. S. , Peterson C.
Published: October 2012

Abstract. During 2009–2010, the State of Florida established a series of air quality monitoring stations to collect data for development of a statewide total maximum daily load (TMDL) for mercury (Hg). At three of these sites, located near Ft. Lauderdale (DVE), Pensacola (OLF), and Tampa Bay (TPA), passive samplers for the measurement of air Hg concentrations and surrogate surfaces for measurement of Hg dry deposition were deployed. While it is known that Hg in wet deposition in Florida is high compared to the rest of the United States, there is little information on Hg dry deposition. The objectives of the work were to: (1) investigate the utility of passive sampling systems for Hg in an area with low and consistent air concentrations as measured by the Tekran® mercury measurement system, (2) estimate dry deposition of gaseous oxidized Hg, and (3) investigate potential sources. This paper focuses on Objective 3. All sites were situated within 15 km of 1000 MW electricity generating plants (EGPs) and major highways. Bi-weekly dry deposition and passive sampler Hg uptake were not directly correlated with the automated Tekran® system measurements, and there was limited agreement between these systems for periods of high deposition. Using diel, biweekly, and seasonal Hg observations, and ancillary data collected at each site, the potential sources of Hg deposited to surrogate surfaces were investigated. With this information, we conclude that there are three major processes/sources contributing to Hg dry deposition in Florida, with these varying as a function of location and time of year. These include: (1) in situ oxidation of locally and regionally derived Hg facilitated by mobile source emissions, (2) indirect and direct inputs of Hg from local EGPs, and (3) direct input of Hg associated with long range transport of air from the northeastern United States. Based on data collected with the surrogate surface sampling system, natural background dry deposition for Florida is estimated to be 0.03 ng m−2 h−1. Deposition associated with mobile sources is 0.10 ng m−2 h−1 at TPA and DVE, and 0.03 ng m−2 h−1 at OLF. Long range transport contributes 0.8 ng m−2 h−1 in the spring. At DVE ~0.10 ng m−2 h−1 is contributed directly or indirectly from local point sources. We also suggest based on the data collected with the Tekran® and passive sampling systems that different chemical forms of GOM are associated with each of these sources.
Parameterization of homogeneous ice nucleation for cloud and climate models based on classical nucleation theory
Authors: Khvorostyanov V. I. , Curry J. A.
Published: October 2012

Abstract. A new analytical parameterization of homogeneous ice nucleation is developed based on extended classical nucleation theory including new equations for the critical radii of the ice germs, free energies and nucleation rates as simultaneous functions of temperature and water saturation ratio. By representing these quantities as separable products of the analytical functions of temperature and supersaturation, analytical solutions are found for the integral-differential supersaturation equation and concentration of nucleated crystals. Parcel model simulations are used to illustrate the general behavior of various nucleation properties under various conditions, for justifications of the further key analytical simplifications, and for verification of the resulting parameterization. The final parameterization is based upon the values of the supersaturation that determines the current or maximum concentrations of the nucleated ice crystals. The crystal concentration is analytically expressed as a function of time and can be used for parameterization of homogeneous ice nucleation both in the models with small time steps and for substep parameterization in the models with large time steps. The crystal concentration is expressed analytically via the error functions or elementary functions and depends only on the fundamental atmospheric parameters and parameters of classical nucleation theory. The diffusion and kinetic limits of the new parameterization agree with previous semi-empirical parameterizations.
Tropospheric NO2 vertical column densities over Beijing: results of the first three-years of ground-based MAX-DOAS measurements (2008–2011) and satellite validation
Authors: Ma J. Z. , Beirle S. , Jin J. L. , Shaiganfar R. , Yan P. , Wagner T.
Published: October 2012

Abstract. Ground-based measurements of scattered sunlight by the Multi Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) have been carried out at an urban site (39.95° N, 116.32° E) in Beijing megacity since 6 August 2008. In this study, we retrieved the tropospheric NO2 vertical column densities (VCDs) over Beijing from these MAX-DOAS observations from August 2008 to September 2011. Over such period, the daytime (08:00–17:00 h Beijing Time) mean tropospheric NO2 VCDs varied from 0.5 to 13.3 with an average of 3.6 during summertime, and from 0.2 to 16.8 with an average of 5.8 during wintertime, all in units of 1016 molecules cm−2. The average diurnal variation patterns of tropospheric NO2 over Beijing appeared to be rather different from one season to another, indicating differences in the mixing layer height, the atmospheric lifetime and the emission patterns. In contrast to previous studies, we find a small weekly cycle of the tropospheric NO2 VCD over Beijing. The NO2 VCD in the late afternoon was the largest on Saturday and the lowest on Sunday, and in the morning it reached a clear maximum on Wednesday. We also find a post Olympic Games effect, with 39–54% decrease in the tropospheric NO2 VCD over Beijing estimated for August of 2008, compared to the following years. The tropospheric NO2 VCDs derived by our ground MAX-DOAS measurements show a good correlation with SCIAMACHY and OMI satellite data. However, compared with the MAX-DOAS measurements, the satellite observations underestimate the tropospheric NO2 VCDs over Beijing systematically, by 43% for SCIAMACHY and 26–38% for OMI (DOMINO v2.0 and DOMINO v1.02). Based on radiative transfer simulations, we show that the aerosol shielding effect can explain this underestimation, while the gradient smoothing effect caused by the coarse spatial resolution of the satellite observations could play an additional role.
Evaluation of factors controlling global secondary organic aerosol production from cloud processes
Authors: He C. , Liu J. , Carlton A. G. , Fan S. , Horowitz L. W. , Levy II H. , Tao S.
Published: October 2012

Abstract. Secondary organic aerosols (SOA) exert a significant influence on ambient air quality and regional climate. Recent field, laboratorial and modeling studies have confirmed that in-cloud processes contribute to a large fraction of SOA production. This study evaluates the key factors that govern the production of cloud-process SOA (SOAcld) in a global scale based on the GFDL coupled chemistry-climate model AM3 in which full cloud chemistry is employed. The association between SOAcld production rate and six factors (i.e. liquid water content (LWC), total carbon chemical loss rate (TCloss), temperature, VOC/NOx, OH, and O3) is examined. We find that LWC alone determines the spatial pattern of SOAcld production, particularly over the tropical, subtropical and temperate forest regions, and is strongly correlated with SOAcld production. TCloss ranks the second and mainly represents the seasonal variability of vegetation growth. Other individual factors are essentially uncorrelated to SOAcld production. We find that the rate of SOAcld production is simultaneously determined by both LWC and TCloss, but responds linearly to LWC and nonlinearly (or concavely) to TCloss. A parameterization based on LWC and TCloss can capture well the spatial and temporal variability of the process-based SOAcld formation (R2=0.5) and can be easily applied to global three dimensional models to represent the SOA production from cloud processes.
Isotopic and lithologic variations of one precisely-dated stalagmite across the Medieval/LIA period from Heilong Cave, central China
Authors: Cui Y. F. , Wang Y. J. , Cheng H. , Zhao K. , Kong X. G.
Published: October 2012

Abstract. Lithologic and isotopic changes of one stalagmite (224 mm in length) from Heilong Cave, Central China, are investigated here in order to explore multiple proxies of monsoon climate. High uranium concentrations (6–10 ppm) ensure Th-230 dates precisely and resultant chronology ranges from ~790 to 1780 AD across the Medieval Warm Period (MWP) to Little Ice Age (LIA). Annually resolved oxygen and carbon isotopic data, gray level and elemental Sr are highly related to macroscopic lithologic changes. A lamination sequence is composed of alternations of white-porous and dark-compact calcite clearly discerned on the polished surface. The dark-compact laminae have low values of gray level, high Sr and δ13C values, indicating periods of low growth rate under dry climate conditions, and vice versa for the white-porous laminae. This suggests that changes in hydrology, matter input of drip water and crystallization process were controlled by cave environments and climates. The alternation of dry and wet periods with a significant periodicity of ~90 yr, as indicated by spectral analyses of the multiple proxies, is further supported by a reconstructed precipitation index from historical documents and instrumental data extending back to 1470 AD. A strong coherence between monsoon proxy of calcite δ18O and the other proxies was observed during the LIA but not during the MWP. This is likely due to changes in atmospheric circulation pattern at the boundary of MWP/LIA. When the Intertropical Convergence Zone shifted southward during the LIA, summer monsoon precipitation at the cave site was probably dominated by the Mei-Yu, resulting in water vapor mainly originated from adjacent oceanic sources.
Differential Bacterial Load on Components of Total Knee Prosthesis in Patients with Prosthetic Joint Infection
Authors: Holinka Johannes , Pilz Magdalena , Hirschl Alexander M. , Graninger Wolfgang , Windhager Reinhard , Presterl Elisabeth
Published: October 2012

Purpose

The purpose of our study was to evaluate and quantify the bacterial adherence on different components of total knee prosthesis with the sonication culture method.

Methods

Explanted components of all patients with presumptive prosthetic or implant infection were treated by sonication separately in sterile containers to dislodge the adherent bacteria from the surfaces and cultured. The bacterial load of the different knee components (femur, tibia, PE-inlay and patella) was evaluated by counting of colony-forming units (CFU) dislodged from the components surfaces using the sonication culture method.

Results

Overall, 27 patients had positive sonication cultures of explanted total knee prostheses. Microorganisms were detected from 88 of 100 explanted components. Twenty femoral components were culture positive and 7 negative, 23 tibial components as well as 23 polyethylene (PE) platforms had positive microorganism detection from the surface. Staphylococcus epidermidis adhered to the highest number of components whereas Staphylococcus aureus yielded the highest load of CFU in the sonication cultures. Although not significant, PE-inlays and tibial components were most often affected. The highest CFU count was detected in polyethylene components.

Conclusion

The sonication culture method is a reliable method to detect bacteria from the components. Additionally, the results demonstrate that bacterial adherence is not affecting a single component of knee prosthesis only. Thus, in septic revision surgery partial prosthetic exchange or exchange of single polyethylene components alone may be not sufficient.
Educar para la democracia
Authors: Bernheim Carlos Tünnermann
Published: October 2012

DOI: http://dx.doi.org/10.5377/cultura.v18i57.796 Cultura de Paz. Managua, Nicaragua • Año XVIII • N° 57 • Mayo - Agosto 2012 P / 2-3
Asumiendo el pasado. Construyendo el presente: dilemas éticos
Authors: Kerber Guillermo
Published: October 2012

En este trabajo el teólogo y filósofo Guillermo Kerber, de manera documentada analiza la evolución, alcance y límites de procesos de construcción de paz y reconciliación a la luz de una perspectiva ética y sociopolítica, proponiendo la compleja articulación de memoria, verdad, justicia, perdón y reconciliación en realidades de posguerra como condición para el desarrollo y consolidación democrática. DOI: http://dx.doi.org/10.5377/cultura.v18i57.797 Cultura de Paz • Año XVIII • N° 57 • Mayo - Agosto 2012 P / 4-19
Esperanzas en Centroamérica ¿Estamos ante un ciclo que abre una nueva oportunidad de vivir?
Authors: Lara Francisco Bautista
Published: October 2012

El experto en seguridad Francisco Bautista Lara, analiza las tendencias de la violencia delictiva en la región centroamericana, identificando últimamente señales positivas, pero afirmando que “la frecuencia de delitos graves cambia de manera sostenible y no ocasional solo cuando se modifican las causas y circunstancias que la originan”. DOI: http://dx.doi.org/10.5377/cultura.v18i57.798 Cultura de Paz • Año XVIII • N° 57 • Mayo - Agosto 2012 P / 20-26
Hitos de la Cultura de Paz en Nicaragua
Authors: Pérez José Miguel Torres
Published: October 2012

El Rev. José Miguel Torres (q.e.p.d), ofrece a grandes pinceladas hitos de construcción de una cultura de paz en el mundo y en Nicaragua, desde el aporte del pensamiento y praxis de figuras símbolos, como desde el quehacer institucional, señala ejes temáticos que hunden sus raíces en nuestra historia, que se constituyen en desafíos para la investigación para la paz y que pueden transformarse en referentes para la forjación de nuestro futuro.DOI: http://dx.doi.org/10.5377/cultura.v18i57.801 Cultura de Paz • Año XVIII • N° 57 • Mayo - Agosto 2012 P / 36-42
Efficient Stereoscopic Video Matching and Map Reconstruction for a Wheeled Mobile Robot
Authors: Montiel-Ross Oscar , Sepúlveda Roberto , Castillo Oscar , Quiñones Jorge
Published: October 2012

This paper presents a novel method to achieve stereoscopic vision for mobile robot (MR) navigation with the advantage of not needing camera calibration for depth (distance) estimation measurements. It uses the concept of the adaptive candidate matching window for stereoscopic correspondence for block matching, resulting in improvements in efficiency and accuracy. An average of 40% of time reduction in the calculation process is obtained. All the algorithms for navigation, including the stereoscopic vision module, were implemented using an original computer architecture for the Virtex 5 FPGA, where a distributed multicore processor system was embedded and coordinated using the Message Passing Interface.
Methodology to Optimize Manufacturing Time for a CNC Using a High Performance Implementation of ACO
Authors: Montiel-Ross Oscar , Medina-Rodríguez Nataly , Sepúlveda Roberto , Melin Patricia
Published: October 2012

In this paper, an efficient methodology to generate optimal and/or quasi-optimal sequences of G commands to minimize the manufacturing time is presented. Our solution starts from original G codes provided by application CAD/CAM software. Here, first we tackled the problem of reducing the time of the travel path for drilling of an industrial robotic manufacturing machine. The methodology can be easily implemented for free distribution or commercial CAD/CAM software without achieving any modification to it. Several experiments that demonstrate how this proposal can help to outperform solutions provided by application software are presented, consistent improvements around 62% were obtained. Moreover, for optimizing the time along the travel path, we present a high performance implementation of Ant Colonies (ACO) known as Parallel ACO (P-ACO) that allows achieving the optimization task efficiently by speeding up the original ACO. A Graphical User Interface that integrates the whole process is shown.
Combining Vision Learning and Interaction for Mobile Robot Path Planning
Authors: Bao Jiatong , Tang Hongru , Song Aiguo
Published: October 2012

This paper addresses the question of how to make a robot learn natural terrain selectively and use the knowledge to estimate the terrain for planning an optimal path. A scheme which combines vision learning and interaction is proposed. The vision learning module employs an online boosting learning algorithm to constantly receive and learn the terrain samples each of which comprise the visual features extracted from the sub terrain region image and the traversability measured by the onboard Inertia Measurement Unit (IMU). Using this knowledge, the robot could estimate the new terrains and search for the optimal path to travel using the particle swarm optimization method. To overcome the shortcoming that the robot could not understand the intricate environment exactly, the vision interaction method, which complements the robot's capacity of terrain estimation with the human reasoning ability of path correction, is further applied. Experimental results show the effectiveness of the proposed method.
Novel Adaptive Forward Neural MIMO NARX Model for the Identification of Industrial 3-DOF Robot Arm Kinematics
Authors: Anh Ho Pham Huy , Nam Nguyen Thanh
Published: October 2012

In this paper, a novel forward adaptive neural MIMO NARX model is used for modelling and identifying the forward kinematics of an industrial 3-DOF robot arm system. The nonlinear features of the forward kinematics of the industrial robot arm drive are thoroughly modelled based on the forward adaptive neural NARX model-based identification process using experimental input-output training data. This paper proposes a novel use of a back propagation (BP) algorithm to generate the forward neural MIMO NARX (FNMN) model for the forward kinematics of the industrial 3-DOF robot arm. The results show that the proposed adaptive neural NARX model trained by a Back Propagation learning algorithm yields outstanding performance and perfect accuracy.
Bilateral Teleoperation in Cartesian Space with Time-Varying Delay
Authors: Chen Zhang , Liang Bin , Zhang Tao , Wang Xueqian
Published: October 2012

The bilateral control of a teleoperator in Cartesian space with time-varying delay is studied in this paper. Compared with the traditional joint-space teleoperation mode, bilateral control in Cartesian space has advantages when dealing with the kinematically dissimilar (KDS) teleoperation systems. A Cartesian space-based PD-like bilateral controller with dissipation factors is designed. Considering the fact that attitude errors derived by rotation matrix cannot be directly used for PD control, a quaternion-based approach is adopted to calculate the attitude errors in Cartesian space. In order to overcome the instability brought about by communication delay, local damping components are employed at both ends of the teleoperator system. The variation of time delay may generate extra energy and influence the stability of the system, thus dissipation factors are introduced into the controller. The stability of the proposed bilateral controller is proved and the simulations show the effectiveness of the approach.
New Fuzzy-Based Retinex Method for the Illumination Normalization of Face Recognition
Authors: Nam Gi Pyo , Park Kang Ryoung
Published: October 2012

We propose a new illumination normalization for face recognition which robust in relation to the illumination variations on mobile devices. This research is novel in the following five ways when compared to previous works: (i) a new fuzzy-based Retinex method is proposed for illumination normalization; (ii) the performance of face recognition is enhanced by determining the optimal parameter of Retinex filtering based on fuzzy logic; (iii) the output of the fuzzy membership function is adaptively determined based on the mean and standard deviations of the grey values of the detected face region; (iv) through the comparison of various defuzzification methods in terms of the accuracy of face recognition, one optimal method was selected; (v) we proved the validations of the proposed method by testing it with various face recognition methods. Experimental results showed that the accuracy of the face recognition with the proposed method was enhanced compared to previous ones.
Face Recognition and Gender Classification Using Orthogonal Nearest Neighbour Feature Line Embedding
Authors: Ho Gang-Feng , Chen Ying-Nong , Han Chin-Chuan , Fan Kuo-Chin
Published: October 2012

In this paper, a novel manifold learning algorithm for face recognition and gender classification – orthogonal nearest neighbour feature line embedding (ONNFLE) – is proposed. Three of the drawbacks of the nearest feature space embedding (NFSE) method are solved: the extrapolation/interpolation error, high computational load and non-orthogonal eigenvector problems. The extrapolation error occurs if the distance from a specified point to one line is small when that line passes through two farther points. The scatter matrix generated by the invalid discriminant vectors does not efficiently preserve the locally topological structure – incorrect selection reduces recognition. To remedy this, the nearest neighbour (NN) selection strategy was used in the proposed method. In addition, the high computational load was reduced using a selection strategy. The last problem involved solving the non-orthogonal eigenvectors found with the NFSE algorithm. The proposed algorithm generated orthogonal bases possessing more discriminating power. Experiments were conducted to demonstrate the effectiveness of the proposed algorithm.
Image Jacobian Matrix Estimation Based on Online Support Vector Regression
Authors: Mao Shangqin , Huang Xinhan , Wang Min
Published: October 2012

Research into robotics visual servoing is an important area in the field of robotics. It has proven difficult to achieve successful results for machine vision and robotics in unstructured environments without using any a priori camera or kinematic models. In uncalibrated visual servoing, image Jacobian matrix estimation methods can be divided into two groups: the online method and the offline method. The offline method is not appropriate for most natural environments. The online method is robust but rough. Moreover, if the images feature configuration changes, it needs to restart the approximating procedure. A novel approach based on an online support vector regression (OL-SVR) algorithm is proposed which overcomes the drawbacks and combines the virtues just mentioned.
Evaluation of Human Prehension Using Grasp Quality Measures
Authors: León Beatriz , Sancho-Bru Joaquín L. , Jarque-Bou Néstor J. , Morales Antonio , Roa Máximo A.
Published: October 2012

One of the main features of the human hand is its grasping ability. Robot grasping has been studied for years and different quality measures have been proposed to evaluate the stability and manipulability of grasps. Although the human hand is obviously more complex than robot hands, the methods used in robotics might be adopted to study the human grasp. The purpose of this work is to propose a set of measures that allow the evaluation of different aspects of the human grasp. The most common robotic grasp quality measures have been adapted to the evaluation of the human hand and a new quality measure – the fatigue index – is proposed in order to incorporate the biomechanical aspect into the evaluation. The minimum set of indices that allows the evaluation of the different aspects of the grasp is obtained from the analysis of a human prehension experiment.
Continuous Full-Body Motion Control of Virtual Human Using Sparse Wiimotes
Authors: Guo Chengyu , Liang Xiaohui , Liu Jie
Published: October 2012

Sparse sensors that recognize full-body human motion and that control the motion of virtual humans have emerged as valuable research tools in the field of human–computer interactions. Here we propose a method for motion recognition and prolonged, continuous generation of motion data based on the recognition results. The only inputs required are the directional accelerations collected by four Wii remotes, which are attached on the four limbs of a human. The extended and continuous signal sequences are separated into small segments that can be described by particular motion content. Use of a fused hidden Markov model (FHMM) during the recognition process ensures the accuracy and efficiency with which independent motion segments are recognized. A graph model enhances the capacity of classification when dealing with a signal sequence associated with a prolonged motion. During the reconstruction and generation processes, an efficient state-based motion graph generates the extended and continuous virtual human motion data, which accurately reflects variation in the movement of the actors. Our method has a strong capacity to classify types of motion upon their recognition and the control process can be applied to a range of applications involving interaction.
Design and Implementation of a Remote Control System for a Bio-Inspired Jumping Robot
Authors: Zhang Jun , Qiao Guifang , Song Guangming , Wang Aimin
Published: October 2012

This paper presents the design and implementation of a remote control system for a bio-inspired jumping robot. The system is composed of a server, a gateway, and a jumping robot. The proposed remote control system is used to monitor the posture of the jumping robot and control it in remote places. A three-axis accelerometer is used to detect the tilts of the robot. A compass is used to sense the azimuth of the robot. The calibrations of the accelerometer and the compass are conducted. The sensor data of the robot can be sent to the server through a ZigBee wireless sensor network (WSN). An algorithm is designed to calculate the posture of the robot from the sensor data. The posture of the robot can be displayed on the human-computer interface of the server using the virtual reality technology of OpenGL. The robots can be controlled by the operator through the interface. Two experiments have been done to verify the posture detection method and test the performance of the system.
Flow measurement accuracies of in‐service residential water meters
Authors: Stoker Devin M. , Barfuss Steven L. , Johnson Michael C.
Published: October 2012

Water utility managers generally agree that water meters, especially mechanical water meters, experience a degradation of accuracy over time. This degradation is a function of several factors, such as wear, water quality, water velocities, throughput volumes, and installation and handling. Both a thorough understanding of the factors that affect meter accuracy and the ability to pinpoint, if possible, the optimal lifespan of any particular type of water meter in a residential distribution system are desirable for improved system management. The purpose of this article was to investigate the relationship between meter accuracy degradation and factors such as age, wear, and throughput for in‐service water meters pulled from utilities across the United States. The information contained in this article is intended to provide insight to water utility managers and decision‐makers about meter replacement programs and schedules.
Factors controlling micropollutant removal during riverbank filtration
Authors: Storck Florian R. , Schmidt Carsten K. , Lange F.T. , Henson J.W. , Hahn K.
Published: October 2012

This article summarizes results of Water Research Foundation report 3136, Removal and Fate of EDCs and PPCPs in Bank Filtration Systems (Storck et al, 2010). The efficiency of bank filtration (BF) as a water treatment process for removing organic trace pollutants in general and, more specifically, pharmaceuticals and personal care products and endocrine‐disrupting compounds (EDCs) was evaluated. Chemical structure and physicochemical properties of a compound, retention time, and redox setting were identified as key factors controlling removal of trace pollutants. Temperature and discharge of the river were found to be important for the minority of compounds investigated. Results obtained from a literature survey of waterworks in the United States and Germany with different site characteristics and trace pollutant concentrations were transferable. Concentrations of more than 70 detectable pollutants were mostly reduced during bank passage. Persistent substances were mainly ethylenediaminetetraacetic acid, sulfamethoxazole, carbamazepine, amidotrizoic acid, naphthalene‐1,5‐disulfonate, and naphthalene‐1,3,5‐trisulfonate.
Plant Growth-Promoting Bacteria: Mechanisms and Applications
Authors: Glick Bernard R.
Published: October 2012

The worldwide increases in both environmental damage and human population pressure have the unfortunate consequence that global food production may soon become insufficient to feed all of the world's people. It is therefore essential that agricultural productivity be significantly increased within the next few decades. To this end, agricultural practice is moving toward a more sustainable and environmentally friendly approach. This includes both the increasing use of transgenic plants and plant growth-promoting bacteria as a part of mainstream agricultural practice. Here, a number of the mechanisms utilized by plant growth-promoting bacteria are discussed and considered. It is envisioned that in the not too distant future, plant growth-promoting bacteria (PGPB) will begin to replace the use of chemicals in agriculture, horticulture, silviculture, and environmental cleanup strategies. While there may not be one simple strategy that can effectively promote the growth of all plants under all conditions, some of the strategies that are discussed already show great promise.
Rhinoplasty and facial asymmetry: Analysis of subjective and anthropometric factors in the Caucasian nose
Authors: Ballin Annelyse Christine , Becker Renata Vecentin , Berger Cezar Augusto Sarraff , Hurtado Johann G. G. Melcherts , Mocellin Marcos , Carvalho Bettina
Published: October 2012

Introduction: Anthropometric proportions and symmetry are considered determinants of beauty. These parameters have significant importance in facial plastic surgery, particularly in rhinoplasty. As the central organ of the face, the nose is especially important in determining facial symmetry, both through the perception of a crooked nose and through the determination of facial growth. The evaluation of the presence of facial asymmetry has great relevance preoperatively, both for surgical planning and counseling.

Aim/Objective: To evaluate and document the presence of facial asymmetry in patients during rhinoplasty planning and to correlate the anthropometric measures with the perception of facial symmetry or asymmetry, assessing whether there is a higher prevalence of facial asymmetry in these patients compared to volunteers without nasal complaints.

Methods: This prospective study was performed by comparing photographs of patients with rhinoplasty planning and volunteers (controls), n = 201, and by evaluating of anthropometric measurements taken from a line passing through the center of the face, until tragus, medial canthus, corner side wing margin, and oral commissure of each side, by statistical analysis (Z test and odds ratio).

Results: None of the patients or volunteers had completely symmetric values. Subjectively, 59% of patients were perceived as asymmetric, against 54% of volunteers. Objectively, more than 89% of respondents had asymmetrical measures. Patients had greater RLMTr (MidLine Tragus Ratio) asymmetry than volunteers, which was statistically significant.

Discussion/Conclusion: Facial asymmetries are very common in patients seeking rhinoplasty, and special attention should be paid to these aspects both for surgical planning and for counseling of patients.