bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficient Reactive Navigation with Exact Collision Determination for 3D Robot Shapes
Authors: Jaimez Mariano , Blanco Jose-Luis , Gonzalez-Jimenez Javier
Published: May 2015

This paper presents a reactive navigator for wheeled mobile robots moving on a flat surface which takes into account both the actual 3D shape of the robot and the 3D surrounding obstacles. The robot volume is modelled by a number of prisms consecutive in height, and the detected obstacles, which can be provided by different kinds of range sensor, are segmented into these heights. Then, the reactive navigation problem is tackled by a number of concurrent 2D navigators, one for each prism, which are consistently and efficiently combined to yield an overall solution. Our proposal for each 2D navigator is based on the concept of the “Parameterized Trajectory Generator” which models the robot shape as a polygon and embeds its kinematic constraints into different motion models.

Extensive testing has been conducted in office-like and real house environments, covering a total distance of 18.5 km, to demonstrate the reliability and effectiveness of the proposed method. Moreover, additional experiments are performed to highlight the advantages of a 3D-aware reactive navigator. The implemented code is available under an open-source licence.
Conceptual Design and Analysis of Four Types of Variable Stiffness Actuators Based on Spring Pretension
Authors: Guo Jishu , Tian Guohui
Published: May 2015

The variable stiffness actuator (VSA) is an open research field. This paper introduces the conceptual design and analysis of four types of novel variable stiffness actuators (VSAs). The main novelty of this paper is focused on the convenience control of the torque and stiffness of the actuator. We do not need to design complicated control strategies to achieve the desired actuating torque and output stiffness. This feature is beneficial for real-time control. In order to achieve this advantage, three types of approximate quadratic springs and four types of stiffness regulation mechanisms are presented. For the first VSA, the relationship between the output stiffness and angular deflection is close to linear, and the fitted quadratic spring is easy to implement and compact. For the second VSA, the output stiffness is only related to the working radius, and the relationship between the exerted torque and angular deflection is linear. For the third VSA, two equivalent quadratic torsion springs are used. Compared with the existing quadratic torsion springs, the design method is simple and the structure size is compact. The stiffness and torque is a linear function of the kinematic parameters of the VSA. The novelty of the fourth VSA is the use of the tension spring set. The approximate quadratic tension spring is compact and easy to implement. The relationship between the output stiffness and the angular deflection is fairly linear. The conceptual layouts and working principles are elaborated for the four actuators. The characteristics of torque and stiffness of the VSAs are presented, and the mechanical solutions are illustrated.
Recorregut de recerca geològica i mineralògica per les terres dels dos pallars: des de Gerri de la Sal a Peramea, Moncortés i a la Torre de Cabdella
Authors: Mata Perelló Josep Maria , Sanz Balagué Joaquim
Published: May 2015

Itinerari realitzat el 13 d'octubre de 2013. En aquesta ocasió, el recorregut de l’itinerari discorrerà, en la seva totalitat pel Sistema Pirinenc, i més concretament ho farà pel Mantell de Bóixols i per la Unitat del Mantell de les Nogueres.Així, l’itinerari s’iniciarà a la població de Gerri de la Sal, per on es faran diverses aturades, després de passar del Mantell de Bóixols a la Unitat del Mantell de les Nogueres, per la qual es farà un breu recorregut fins als voltants la Pobleta de Bellvei, passant per Montcortès i Peramea. Després, el recorregut continuarà fins arribar a la Torre de Cabdella, per on finalitzarà el recorregut de l’itinerariPer d’altra banda, el recorregut de l’itinerari discorrerà per dues comarques, les quals pertanyen a la Regió de Tremp (o de Tremp - Seu d’Urgell). Així, s’iniciarà a la comarca del Pallars Sobirà per on discorrerà entre Gerri de la Sal i Montcortès. Posteriorment, el recorregut entrarà al Pallars Jussà, anant des de les immediacions de la Pobleta de Bellvei fins a la fi del recorregut, prop de la Torre de Cabdella, per on finalitzarà el recorregut.
Recerca geològica i mineralògica per la comarca del Pallars Sobirà: des de Sort i la Bàstida de Sort a Rialp, Montenartró, Romadriu i a Sant Joan de l´Erm Nou
Authors: Mata Perelló Josep Maria , Sanz Balagué Joaquim
Published: May 2015

Itinerari realitzat el 20 d'octubre de 2013. En aquesta ocasió, la totalitat del recorregut de l´itinerari discorrerà pel Sistema Pirinenc. Així, en la seva primera part, entre Sort i els Hostalets de la Bastida (prop de Rialp de Noguera) ho farà per la Unitat del Mantell de les Nogueres (la qual forma part de les tradicionalment anomenades Serres Exteriors Prepirinenques). En aquest tram, trobarem fonamentalment afloraments dels materials mesozoics del triàsic Superior, del Keuper.Després, entre Rialp de Noguera i les immediacions de Sant Joan de l´Erm (al final del recorregut), el recorregut de l´itinerari discorrerà per la Zona Axial Pirinenca (en concret per la denominada Unitat dels Apilaments de la Zona Axial). En aquest tram del recorregut, trobarem fonamentalment afloraments dels materials paleozoics, de l´Ordovicià, del Silurià, del Devonià i del Carbonífer.Per altra banda, el recorregut de l´itinerari discorrerà íntegrament per una sola comarca, concretament per la del Pallars Sobirà (encara que finalitzarà prop de la comarca de l´Alt Urgell), situada dintre de la Regió de Tremp (o de Tremp-Seu d´Urgell).
Recorregut de recerca geològica i mineralògica per les comarques del Baix Ebre i de la Ribera d´Ebre: des del Perelló a l´antic circuït de Calafat i a Tivissa
Authors: Mata Perelló Josep Maria , Sanz Balagué Joaquim
Published: May 2015

Itinerari realitzat el 2 de febrer de 2014. En aquesta ocasió, es realitzarà un recorregut geològic a través de diferents indrets de la Depressió Geològica de l´Ebre; i més concretament pels sectors corresponents a la seva Depressió Central. Així, tot el recorregut transitarà entre afloraments dels materials terciaris (de l´Eocè i de l´Oligocè) i quaternaris que reblen aquesta depressió. Així, el recorregut l´iniciarem entre els afloraments cenozoics de la Formació Artés, situada al trànsit de l´Eocè a l´Oligocè, dintre de l´anomenat Complex Lacustre de l´Anoia (que trobarem entre Jorba i les immediacions de Sant Martí de Tous) i el finalitzarem entre els afloraments de la Formació Tàrrega, ja dintre de l´Oligocè, integrant del Complex Lacustre de la Segarra (que trobarem fonamentalment entre les immediacions d´Aguiló i la Panadella). Per altra banda, quasi la totalitat del recorregut transitarà per la comarca d´Anoia, integrant de la Catalunya Central. Tot això a excepció dels voltants d´Aguiló, per on es transitarà per la Conca de Barberà (encara que per la Baixa Segarra); i també pels voltants de Bellmunt de Segarra (situat dintre de la comarca de la Segarra).
Recorregut de recerca geològica i mineralògica per la comarca del Pallars Jussà: des de Senterada, a la Pobleta de Bellveí, al Castell i a Sallente
Authors: Mata Perelló Josep Maria , Sanz Balagué Joaquim
Published: May 2015

Itinerari realitzat el 15 de febrer de 2014. En aquesta ocasió, el recorregut de l’itinerari discorrerà, quasi en la seva totalitat pel Sistema Mediterrani, i més concretament per la Serralada Prelitoral Catalana (la seva unitat més externa). Així doncs, la quasi totalitat del recorregut per les vessants SE del Farell, per aquesta unitat geològica. En aquesta part del recorregut, es trobaran materials mesozoics del Triàsic (i molt ocasionalment materials paleozoics de l´Ordovicià). Tot i així, part dels recorreguts es realitzaran per la Depressió Geològica de l´Ebre, entre afloraments de materials cenozoics. Per altra banda, i com ja s’entreveu al títol, el recorregut de l’itinerari discorrerà sols per la comarca del Vallès Occidental, pel terme de Sentmenat, en la seva totalitat, també.
Recorregut de recerca geològica i mineralògica per la comarca del Pallars Jussà: des d´Espui, cap al Coll de Triador, l´Estany Gento, l´Estany Tort i cap a Colomines
Authors: Mata Perelló Josep Maria , Sanz Balagué Joaquim
Published: May 2015

Itinerari realitzat el 7 de setembre de 2013. En aquesta ocasió, la totalitat del recorregut de l’itinerari es desenvoluparà per una sola unitat geològica: concretament pel Sistema Pirinenc, i més exactament per la zona de contacte entre la Unitat de les Nogueres i la Zona Axial Pirinenca, situada al nord de l’anterior. D´aquesta manera, el recorregut s’iniciarà a la població d´Espui (del terme de la Torre de Cabdella), situada a la Unitat de les Nogueres.Així, a partir d’aquí l’itinerari transitarà per aquesta unitat acabada d´esmentar, anant cap a l´Estany Gento. Més amunt, en arribar-hi, es trobarà el contacte amb la Zona Axial Pirinenca, que ja no s´abandonarà en tota la resta del recorregut.Així, inicialment, s´aniran trobant afloraments dels materials paleozoics del Silurià i del Devonià. Més endavant, en arribar a la Zona Axial, es trobaran granits i granodiorites carboníferes., així com afloraments paleozoics de l´Ordovicià, Silurià i Devonià, fonamentalment.Per d’altra banda, aquest itinerari es desenvoluparà dintre de la comarca del Pallars Jussà (per la qual es transitarà entre la població d´Espui i la fi del recorregut, per les immediacions de l´Estany de Colomines). Així, tot el recorregut de l´itinerari s´efectuarà per la part més alta de la Vall Fosca, una subcomarca del Pallars Jussà. Aquesta subcomarca es troba situada íntegrament dintre de la conca fluvial del Noguera de Flamisell, afluent del Noguera Pallaresa a la Pobla de Segur.
Recorregut de recerca geològica i mineralògica per la comarca del Pallars jussà: des de la Torre de Cabdella cap a Espui, Cabdella, Sallente i cap l´Estany Gento
Authors: Mata Perelló Josep Maria , Sanz Balagué Joaquim
Published: May 2015

Itinerari realitzat el 7 de setembre de 2013. En aquesta ocasió, la totalitat del recorregut de l’itinerari es desenvoluparà per una sola unitat geològica: concretament pel Sistema Pirinenc, i més exactament per la zona de contacte entre la Unitat de les Nogueres i la Zona Axial Pirinenca, situada al nord de l’anterior. D’aquesta manera, el recorregut s’iniciarà a la població de la Torre de Cabdella (situada a la Unitat de les Nogueres), per a finalitzar a l’Estany Gento (situat ja dintre de la Zona Axial Pirinenca).Així, a partir de la Torre de Cabdella, l’itinerari transitarà per la primera unitat esmentada, anant cap a les poblacions d´Espui i de Cabdella. Més amunt, per les immediacions de Sallente, s’arribarà al contacte amb la Zona Axial Pirinenca, que ja no s’abandonarà en tota la resta del recorregut.Així, inicialment, s’aniran trobant afloraments dels materials paleozoics del Silurià i del Devonià. Més endavant, en arribar a la Zona Axial, es trobaran granits i granodiorites carboníferes., així com afloraments paleozoics de l´Ordovicià, Silurià i Devonià, fonamentalment.Per d’altra banda, aquest itinerari es desenvoluparà dintre de la comarca del Pallars Jussà (per la qual es transitarà entre la població de la Torre de Cabdella i la fi del recorregut, per les immediacions de l’Estany Gento). Així, tot el recorregut de l’itinerari s’efectuarà per la part més alta de la Vall Fosca, una subcomarca del Pallars Jussà. Aquesta subcomarca es troba situada íntegrament dintre de la conca fluvial del Noguera de Flamisell, afluent del Noguera Pallaresa a la Pobla de Segur.
Recorregut de recerca geològica i mineralògica per la comarca del Pallars Jussà: des de Basturs cap Abella de la Conca, a Bóixols i a Isona
Authors: Mata Perelló Josep Maria , Sanz Balagué Joaquim
Published: May 2015

Itinerari realitzat el 8 de setembre de 2013. En aquesta ocasió, el recorregut de l’itinerari discorrerà, en la seva quasi totalitat pel Sistema Pirinenc, i més concretament ho farà per la seva Unitat Sudpirinenca Central (també anomenada com a les Serres Exteriors Prepirinenques).En concret, el recorregut del present itinerari passarà per dos dels seus sectors més representatius; concretament pel Mantell del Montsec (més situat al Sud) i també per alguns indrets del Mantell de Bóixols.Així, l’itinerari s’iniciarà dintre del Mantell del Montsec (molt prop del seu contacte amb el Mantell de Bóixols). Després en bona part del recorregut, en transitarà per la zona de contacte entre els dos mantells anteriors. Més endavant, després travessar part del segon mantell, el recorregut tornarà a penetrar-se al Mantell del Montsec, per on finalitzarà el recorregut de l’itinerari.Per altra banda, el recorregut de l’itinerari discorrerà íntegrament per una sola comarca: per la del Pallars Jussà (de la Regió de Tremp).
Recorregut de recerca geològica i mineralògica per les comarques del Pallars Jussà i de l´Alta Ribagorça: des de les Esglèsies a la Mola d´Amunt, Sentís, Sas i a Erta
Authors: Mata Perelló Josep Maria , Sanz Balagué Joaquim
Published: May 2015

Itinerari realitzat el 22 de setembre de 2013. En aquesta ocasió, la totalitat del recorregut de l´itinerari es desenvoluparà per una sola unitat geològica: concretament pel Sistema Pirinenc i més exactament pel Mantell de les Nogueres, en la seva totalitat. Tot i així, en diversos trams centrals del recorregut ens aproparem molt (sense arribar a entrar-hi) a la Zona Axial Pirinenca, o més concretament pels denominats Apilaments antiformes de la Zona Axial Pirinenca.Així, al llarg del recorregut, trobarem afloraments dels materials mesozoics (del Triàsic) i dels paleozoics (del Devonià, Carbonífer i Permià), que formen part de l´esmentat Mantell de les Nogueres. Aquests materials els anirem trobant al llarg de trot el recorregut de l´itinerari, entre les Esglésies i les immediacions d´Erta.Per altra banda, cal dir que aquest itinerari es desenvoluparà per dues de les comarques que configuren els Pirineus. Així, s´iniciarà dintre del Pallars Jussà, per on es circularà fins arribar a les immediacions d´Erta. Després, el recorregut entrarà a la comarca de l´Alta Ribagorça, per a finalitzar molt a prop de la població darrerament esmentada, per on finalitzarà el recorregut d´aquest itinerari.
Recorregut de recerca geològica i mineralògica per la comarca de l´Alta Ribagorça: des d´Erta a Peranera i a Malpàs
Authors: Mata Perelló Josep Maria , Sanz Balagué Joaquim
Published: May 2015

Itinerari realitzat el 22 de setembre de 2013. En aquesta ocasió, la totalitat del recorregut de l´itinerari es desenvoluparà per una sola unitat geològica: concretament pel Sistema Pirinenc i més exactament pel Mantell de les Nogueres, en la seva totalitat. Tot i així, en diversos trams centrals del recorregut ens aproparem molt (sense arribar a entrar-hi) a la Zona Axial Pirinenca, o més concretament pels denominats Apilaments antiformes de la Zona Axial Pirinenca.Així, al llarg del recorregut, trobarem afloraments dels materials mesozoics (del Triàsic) i dels paleozoics (del Devonià, Carbonífer i Permià), que formen part de l´esmentat Mantell de les Nogueres. Aquests materials els anirem trobant al llarg de trot el recorregut de l´itinerari, entre la Mola d´Amunt i Malpàs.Per d´altra banda, cal dir que aquest itinerari es desenvoluparà per dues de les comarques que configuren els Pirineus. Així, s´iniciarà dintre del Pallars Jussà, per on es circularà fins arribar a les immediacions d´Erta. Després, el recorregut entrarà a la comarca de l´Alta Ribagorça, per on es circularà entre Erta i Malpàs, per on finalitzarà el recorregut d´aquest itinerari.
Apunts per a un recorregut de recerca geològica i mineralògica per les comarques del Pallars jussà i de l´Alt Urgell: des de la Pobla de Segur a Pessonada, Carreu, als Prats de Montanissel i a Bóixols
Authors: Mata Perelló Josep Maria , Sanz Balagué Joaquim
Published: May 2015

Itinerari realitzat el 22 de setembre de 2013. En aquesta ocasió, el recorregut de l’itinerari discorrerà, en la seva quasi totalitat pel Sistema Pirinenc, i més concretament ho farà per la seva Unitat Sudpirinenca Central (també anomenada com a les Serres Exteriors Prepirinenques).En concret, el recorregut del present itinerari passarà per dos dels seus sectors més representatius; concretament pel Mantell del Montsec (més situat al Sud) i també per alguns indrets del Mantell de Bóixols. Cal dir que el recorregut de l´itinerari, transitarà fonamentalment per aquest darrer.Així, l’itinerari s’iniciarà dintre del Mantell del Bóixols (molt prop del seu contacte amb el Mantell de la Unitat de les Nogueres). Després en bona part del recorregut, en transitarà pel primer mantell esmentat. Més endavant, després travessar bona part d´aquest mantell, el recorregut s´aproparà, fins a penetrar lleugerament dintre del Mantell del Montsec, per on finalitzarà el recorregut de l’itinerari.Per altra banda, el recorregut de l’itinerari discorrerà en la seva major part per la comarca del Pallars Jussà, fent un petit recorregut per la de l´Alt Urgell (ambdues de la Regió de Tremp – la Seu d´Urgell).
Homosexual men in HIV serodiscordant relationships: implications for HIV treatment as prevention research
Authors: Bavinton Benjamin R , Jin Fengyi , Mao Limin , Zablotska Iryna , Prestage Garrett P , Grulich Andrew E
Published: May 2015

Introduction

Studies in heterosexual HIV serodiscordant couples have provided critical evidence on the role of HIV treatments in reducing HIV transmission risk. However, there are limited data regarding the effect of treatment on HIV transmission in homosexual male couples. We examined features of male homosexual HIV serodiscordant relationships that may impact upon the design of HIV treatment and transmission studies.

Methods

Data were from a prospective cohort study of HIV‐negative homosexual men in Sydney, Australia. Men were followed up with six‐monthly interviews and annual testing for HIV. Characteristics of men in HIV serodiscordant and seroconcordant relationships at baseline were compared, and a longitudinal analysis performed of rate of relationship break‐up and of HIV incidence.

Results

At baseline, 5.5% of participants (n=79) had an HIV‐positive partner. Most (80.8%) of these relationships were non‐monogamous, and 36.7% of men reported recent unprotected anal intercourse (UAI) with casual partners. The rate of relationship break‐up was 29.5 per 100 person‐years. Half of men in serodiscordant relationships (49.4%) reported recent UAI with their regular partners. HIV incidence was 2.2 per 100 person‐years. It was substantially higher in relationships of less than one year's duration (6.1 per 100 person‐years) and in men who reported unprotected receptive anal intercourse with ejaculation with their regular partners (15.5 per 100 person‐years).

Conclusions

Levels of HIV transmission risk and incidence were high, particularly in early relationships. Rates of relationship break‐up were high. These data suggest that studies of HIV treatments and transmission in homosexual serodiscordant couples should focus on early relationships so as not to underestimate risk, and sample sizes must allow for high rates of relationship break‐up.
Typifications in Andersonia (Ericaceae: Epacridoideae)
Authors: Lemson Kristina L.
Published: May 2015

Lectotypes are selected for Andersonia R.Br (Ericaceae) and eight taxa within the genus: A. aristata Lindl. A. brevifolia Sond., A. heterophylla Sond., A. involucrata Sond., A. sprengelioides R.Br., A. lehmanniana subsp. lehmanniana (Sond.)L.Watson and A. lehmanniana subsp. pubescens (Sond.)L.Watson. Andersonia patens Sond. is lectotypified in synonymy with A. sprengelioides.
Tomographic mapping of a coastal upwelling and the associated diurnal internal tides in Hiroshima Bay, Japan
Authors: Zhang Chuanzheng , Kaneko Arata , Zhu Xiao‐Hua , Gohda Noriaki
Published: May 2015

Temperature variations caused by a typhoon were measured in the northern part of Hiroshima Bay by four coastal acoustic tomography (CAT) systems. The horizontal distributions of depth‐averaged temperature from 0 to 8 m were mapped at 10 min intervals between the 11 and 25 September 2013. The horizontal distributions of a coastal upwelling and the associated diurnal internal tides were reconstructed well by regularized inversion based on the grid segmented method, using one‐way travel time data along five successful sound transmission lines. Station‐to‐station ranges were corrected in such a way that sound speed (determined from one‐way travel time data) was equal to sound speed calculated from a couple of CTD (conductivity‐temperature‐depth) data sets on each transmission line. In addition, all station positions were adjusted to make focal points at the geographical positions of the transducers. The corrections increased the accuracy of temperature measurements to make temperature errors as small as 0.073–0.079°C. The high accuracy made it possible to map the temperature structure with a variation range of less than 0.5°C. An upwelling grew from 16 to 17 September, due to a typhoon‐derived northerly wind. The diurnal internal tide resonated with the semidiurnal external tide, which was pronounced after the upwelling decayed (18 September), around the time the spring tide occurred. The upwelling and mixing fractions were formulated. These fractions increased continuously as the upwelling grew. Complete mixing was observed during the upwelling's mature phase.
Seasonality of westerly moisture transport in the East Asian summer monsoon and its implications for interpreting precipitation δ18O
Authors: Baker Alexander J. , Sodemann Harald , Baldini James U. L. , Breitenbach Sebastian F. M. , Johnson Kathleen R. , van Hunen Jeroen , Zhang Pingzhong
Published: May 2015

East Asian summer monsoon (EASM) rainfall impacts the world's most populous regions. Accurate EASM rainfall prediction necessitates robust paleoclimate reconstructions from proxy data and quantitative linkage to modern climatic conditions. Many precisely dated oxygen isotope records from Chinese stalagmites have been interpreted as directly reflecting past EASM rainfall amount variability, but recent research suggests that such records instead integrate multiple hydroclimatic processes. Using a Lagrangian precipitation moisture source diagnostic, we demonstrate that EASM rainfall is primarily derived from the Indian Ocean. Conversely, Pacific Ocean moisture export peaks during winter, and the moisture uptake area does not differ significantly between summer and winter and is thus a minor contributor to monsoonal precipitation. Our results are substantiated by an accurate reproduction of summer and winter spatial rainfall distributions across China. We also correlate modern EASM rainfall oxygen isotope ratios with instrumental rainfall amount and our moisture source data. This analysis reveals that the strength of the source effect is geographically variable, and differences in atmospheric moisture transport may significantly impact the isotopic signature of EASM rainfall at the Hulu, Dongge, and Wanxiang Cave sites. These results improve our ability to isolate the rainfall amount signal in paleomonsoon reconstructions and indicate that precipitation across central and eastern China will directly respond to variability in Indian Ocean moisture supply.
Environmental controls on the biogeography of diazotrophy and Trichodesmium in the Atlantic Ocean
Authors: Snow J. T. , Schlosser C. , Woodward E. M. S. , Mills M. M. , Achterberg E. P. , Mahaffey C. , Bibby T. S. , Moore C. M.
Published: May 2015

The cyanobacterium Trichodesmium is responsible for a significant proportion of the annual “new” nitrogen introduced into the global ocean. Despite being arguably the best studied marine diazotroph, the factors controlling the distribution and growth of Trichodesmium remain a subject of debate, with sea surface temperature, the partial pressure of CO2, and nutrients including iron (Fe) and phosphorus (P), all suggested to be important. Synthesizing data from seven cruises collectively spanning large temporal and spatial scales across the Atlantic Ocean, including two previously unreported studies crossing the largely undersampled South Atlantic gyre, we assessed the relationship between proposed environmental drivers and both community N2 fixation rates and the distribution of Trichodesmium. Simple linear regression analysis would suggest no relationship between any of the sampled environmental variables and N2 fixation rates. However, considering the concentrations of iron and phosphorus together within a simplified resource‐ratio framework, illustrated using an idealized numerical model, indicates the combined effects these nutrients have on Trichodesmium and broader diazotroph biogeography, alongside the reciprocal maintenance of different biogeographic provinces of the (sub)tropical Atlantic in states of Fe or P oligotrophy by diazotrophy. The qualitative principles of the resource‐ratio framework are argued to be consistent with both the previously described North‐South Atlantic contrast in Trichodesmium abundance and the presence and consequence of a substantial non‐Trichodesmium diazotrophic community in the western South Atlantic subtropical gyre. A comprehensive, observation‐based explanation of the interactions between Trichodesmium and the wider diazotrophic community with iron and phosphorus in the Atlantic Ocean is thus revealed.
Explanation of Pi2 pulsations in auroral zone: Azimuthal propagation of ionospheric loop currents
Authors: Saka O. , Hayashi K. , Leonovich A. S.
Published: May 2015

The modes of Pi2 oscillations in space and on the ground, particularly in the auroral zone, have been discussed individually. The former is associated with the cavity oscillations either ideally trapped or partially trapped in the magnetosphere, and the latter is associated with the transient oscillations of the currents in the ionosphere. In this report, we show that ground polarization patterns (ellipticity and major axis orientation) of Pi2 pulsations in the nighttime sector from auroral zone to midlatitudes can be explained by the wave polarizations in the magnetosphere transmitted by the fundamental and the third harmonic deformations of the geomagnetic field lines. These ground polarization patterns are, however, understood alternatively as propagating large‐scale ionospheric loop currents in auroral zone expanding ~1000 km longitudinally. One pattern propagates eastward in the dawn sector and the other westward in the dusk sector. The propagating loop currents for the generation of the ground polarizations were consistent with the vortical motion of auroras observed by all‐sky imager in association with the Pi2 pulsations. Propagation of the ionospheric loop currents and vortical motion of auroras are a consequence of the Pi2‐associated magnetosphere and ionosphere coupling through the Alfvén waves.
Seismogeodesy of the 2014Mw6.1 Napa earthquake, California: Rapid response and modeling of fast rupture on a dipping strike‐slip fault
Authors: Melgar Diego , Geng Jianghui , Crowell Brendan W. , Haase Jennifer S. , Bock Yehuda , Hammond William C. , Allen Richard M.
Published: May 2015

Real‐time high‐rate geodetic data have been shown to be useful for rapid earthquake response systems during medium to large events. The 2014Mw6.1 Napa, California earthquake is important because it provides an opportunity to study an event at the lower threshold of what can be detected with GPS. We show the results of GPS‐only earthquake source products such as peak ground displacement magnitude scaling, centroid moment tensor (CMT) solution, and static slip inversion. We also highlight the retrospective real‐time combination of GPS and strong motion data to produce seismogeodetic waveforms that have higher precision and longer period information than GPS‐only or seismic‐only measurements of ground motion. We show their utility for rapid kinematic slip inversion and conclude that it would have been possible, with current real‐time infrastructure, to determine the basic features of the earthquake source. We supplement the analysis with strong motion data collected close to the source to obtain an improved postevent image of the source process. The model reveals unilateral fast propagation of slip to the north of the hypocenter with a delayed onset of shallow slip. The source model suggests that the multiple strands of observed surface rupture are controlled by the shallow soft sediments of Napa Valley and do not necessarily represent the intersection of the main faulting surface and the free surface. We conclude that the main dislocation plane is westward dipping and should intersect the surface to the east, either where the easternmost strand of surface rupture is observed or at the location where the West Napa fault has been mapped in the past.
Snow depth on Arctic sea ice derived from radar: In situ comparisons and time series analysis
Authors: Holt Benjamin , Johnson Michael P. , Perkovic‐Martin Dragana , Panzer Ben
Published: May 2015

The snow radar being flown on NASA's Operation IceBridge, ongoing aircraft campaigns to the Arctic and the Antarctic are providing unique observations of the depth of snow on the sea ice cover. In this paper, we focus on the radar‐derived snow depth results from the 2009–2012 Arctic campaigns. We develop and evaluate the use of a distinct snow layer tracker to measure snow depth based on a Support Vector Machine (SVM) supervised learning algorithm. The snow radar is designed to detect both the air‐snow and snow‐ice interfaces using ultrawideband frequencies from 2 to 8 GHz. The quality, errors, and repeatability of the snow radar snow depth estimates are examined, based on comparisons with in situ data obtained during two separate sea ice field campaigns, the GreenArc 2009 and the CryoVEx 2011 campaigns off Greenland in the Lincoln Sea. Finally, we analyze 4 years (2009–2012) of three annually repeated sea ice flight lines obtained in early spring, located off Greenland and the Canadian Arctic. We examine the annual variations of snow depth differences between perennial and seasonal ice when available. Overall, the snow layer tracker produced consistent, accurate results for snow depths between 0.10 and ∼0.60 m. This was confirmed with comparisons with the two data sets from the in situ measurement campaigns as well as with the time series analysis, and is consistent with other published results.
Mitigating errors in surface temperature forecasts using approximate radiation updates
Authors: Hogan Robin J. , Bozzo Alessio
Published: May 2015

Due to computational expense, the radiation schemes in many weather and climate models are called infrequently in time and/or on a reduced spatial grid. The former can lead to a lag in the diurnal cycle of surface temperature, while the latter can lead to large surface temperature errors at coastal land points due to surface fluxes computed over the ocean being used where the skin temperature and surface albedo are very different. This paper describes a computationally efficient solution to these problems, in which the surface longwave and shortwave fluxes are updated every time step and grid point according to the local skin temperature and albedo. In order that energy is conserved, it is necessary to compute the change to the net flux profile consistent with the changed surface fluxes. The longwave radiation scheme has been modified to compute also the rate of change of the profile of upwelling longwave flux with respect to the value at the surface. Then at each grid point and time step, the upwelling flux and heating‐rate profiles are updated using the new value of skin temperature. The computational cost of performing approximate radiation updates in the ECMWF model is only 2% of the cost of the full radiation scheme, so increases the overall cost of the model by only of order 0.2%. Testing the new scheme by running daily 5 day forecasts over an 8 month period reveals significant improvement in 2 m temperature forecasts at coastal stations compared to observations.
Multi‐agent adaptive consensus of networked systems on directed graphs
Authors: Radenkovic Miloje , Tadi Mohsen
Published: May 2015

This paper considers adaptive consensus problem on directed graphs of multi‐agent systems with unknown control directions. The proposed consensus protocol assumes that each agent receives information about delayed values of state and control signals of respective neighbors. In case of unknown sign of the high‐frequency gain of agent dynamics, the proposed algorithm employs Nussbaum‐like switching function. The algorithm allows for a designer to select low gain or high gain consensus protocols. Assuming that the underlying graph is strongly connected, it is proved that all agent states converge toward the same value, and the inter‐agent coupling parameters are convergent functions. Copyright © 2015 John Wiley & Sons, Ltd.
Concurrent monitoring of operating condition deviations and process dynamics anomalies with slow feature analysis
Authors: Shang Chao , Yang Fan , Gao Xinqing , Huang Xiaolin , Suykens Johan A.K. , Huang Dexian
Published: May 2015

Latent variable (LV) models have been widely used in multivariate statistical process monitoring. However, whatever deviation from nominal operating condition is detected, an alarm is triggered based on classical monitoring methods. Therefore, they fail to distinguish real faults incurring dynamics anomalies from normal deviations in operating conditions. A new process monitoring strategy based on slow feature analysis (SFA) is proposed for the concurrent monitoring of operating point deviations and process dynamics anomalies. Slow features as LVs are developed to describe slowly varying dynamics, yielding improved physical interpretation. In addition to classical statistics for monitoring deviation from design conditions, two novel indices are proposed to detect anomalies in process dynamics through the slowness of LVs. The proposed approach can distinguish whether the changes in operating conditions are normal or real faults occur. Two case studies show the validity of the SFA‐based process monitoring approach. © 2015 American Institute of Chemical Engineers AIChE J, 61: 3666–3682, 2015
Outcome of conditioning intensity in acute myeloid leukemia with monosomal karyotype in patients over 45 year‐old: A study from the acute leukemia working party (ALWP) of the European group of blood and marrow transplantation (EBMT)
Authors: Poiré Xavier , Labopin Myriam , Cornelissen Jan J. , Volin Liisa , Richard Espiga Carlos , Veelken J. Hendrik , Milpied Noël , Cahn Jean‐Yves , Yacoub‐Agha Ibrahim , van Imhoff Gustaaf W. , Michallet Mauricette , Michaux Lucienne , Nagler Arnon , Mohty Mohamad
Published: May 2015

Acute myeloid leukemia with monosomal karyotype (MK AML) carries a very poor prognosis, even after allogeneic stem cell transplantation (SCT). However, SCT remains the only curative option in this high‐risk population. Because myeloablative conditioning regimen (MAC) is associated with less relapse, we hypothesized that more intensive conditioning regimen might be beneficial for MK AML patients. We reviewed 303 patients over age 45 diagnosed with either de novo or secondary MK AML. One hundred and five patients received a MAC and 198 a reduced‐intensity conditioning (RIC). The median age at SCT was 57‐year‐old, significantly lower in the MAC (53‐year‐old) than in the RIC group (59‐year‐old). The median follow‐up was 42 months (range, 3 − 156 months). The 3‐year overall survival (OS), leukemia‐free survival (LFS), and relapse rate (RR) were not significantly different between both groups with overall values of 34%, 29%, and 51%, respectively. On the contrary, the 3‐year nonrelapse mortality (NRM) was significantly higher in MAC recipients (28%) compared with RIC patients (16%, P = 0.004). The incidence of Grades II to IV acute graft‐versus‐host disease (GvHD) was significantly higher after a MAC (30.5%) than after a RIC (19.3%, P = 0.02). That of chronic GvHD was comparable between both groups (35%) and did not impact on LFS. Interestingly, within our MK AML cohort, hypodiploidy was significantly associated with worse outcomes. Due to reduced toxicity and comparable OS, LFS, and RR, RIC appears as a good transplant option in the very high‐risk population, including older patients, diagnosed with MK AML. Am. J. Hematol. 90:719–724, 2015. © 2015 Wiley Periodicals, Inc.
Intraneural GJB1 gene delivery improves nerve pathology in a model of X‐linked Charcot–Marie–Tooth disease
Authors: Sargiannidou Irene , Kagiava Alexia , Bashiardes Stavros , Richter Jan , Christodoulou Christina , Scherer Steven S. , Kleopa Kleopas A.
Published: May 2015

Objective

X‐linked Charcot–Marie–Tooth disease (CMT1X) is a common inherited neuropathy caused by mutations in the GJB1 gene encoding the gap junction protein connexin32 (Cx32). Clinical studies and disease models indicate that neuropathy mainly results from Schwann cell autonomous, loss‐of‐function mechanisms; therefore, CMT1X may be treatable by gene replacement.

Methods

A lentiviral vector LV.Mpz‐GJB1 carrying the GJB1 gene under the Schwann cell–specific myelin protein zero (Mpz) promoter was generated and delivered into the mouse sciatic nerve by a single injection immediately distal to the sciatic notch. Enhanced green fluorescent protein (EGFP) reporter gene expression was quantified and Cx32 expression was examined on a Cx32 knockout (KO) background. A gene therapy trial was performed in a Cx32 KO model of CMT1X.

Results

EGFP was expressed throughout the length of the sciatic nerve in up to 50% of Schwann cells starting 2 weeks after injection and remaining stable for up to 16 weeks. Following LV.Mpz‐GJB1 injection into Cx32 KO nerves, we detected Cx32 expression and correct localization in non–compact myelin areas where gap junctions are normally formed. Gene therapy trial by intraneural injection in groups of 2‐month‐old Cx32 KO mice, before demyelination onset, significantly reduced the ratio of abnormally myelinated fibers (p = 0.00148) and secondary inflammation (p = 0.0178) at 6 months of age compared to mock‐treated animals.

Interpretation

Gene delivery using a lentiviral vector leads to efficient gene expression specifically in Schwann cells. Restoration of Cx32 expression ameliorates nerve pathology in a disease model and provides a promising approach for future treatments of CMT1X and other inherited neuropathies. Ann Neurol 2015;78:303–316
Patterns of Risk for Multiple Co‐Occurring Medical Conditions Replicate Across Distinct Cohorts of Children with Autism Spectrum Disorder
Authors: Aldinger Kimberly A. , Lane Christianne J. , Veenstra‐VanderWeele Jeremy , Levitt Pat
Published: May 2015

Children with autism spectrum disorder (ASD) may present with multiple medical conditions in addition to ASD symptoms. This study investigated whether there are predictive patterns of medical conditions that co‐occur with ASD, which could inform medical evaluation and treatment in ASD, as well as potentially identify etiologically meaningful subgroups. Medical history data were queried in the multiplex family Autism Genetic Resource Exchange (AGRE). Fourteen medical conditions were analyzed. Replication in the Simons Simplex Collection (SSC) was attempted using available medical condition data on gastrointestinal disturbances (GID), sleep problems, allergy and epilepsy. In the AGRE cohort, no discrete clusters emerged among 14 medical conditions. GID and seizures were enriched in unaffected family members, and together with sleep problems, were represented in both AGRE and SSC. Further analysis of these medical conditions identified predictive co‐occurring patterns in both samples. For a child with ASD, the presence of GID predicts sleep problems and vice versa, with an approximately 2‐fold odds ratio in each direction. These risk patterns were replicated in the SSC sample, and in addition, there was increased risk for seizures and sleep problems to co‐occur with GID. In these cohorts, seizure alone was not predictive of the other conditions co‐occurring, but behavioral impairments were more severe as the number of co‐occurring medical symptoms increased. These findings indicate that interdisciplinary clinical care for children with ASD will benefit from evaluation for specific patterns of medical conditions in the affected child and their family members. Autism Res 2015, 8: 771–781. © 015 The Authors Autism Research published by Wiley Periodicals, Inc. on behalf of International Society for Autism Research.
Type 1 diabetes exacerbates blood–brain barrier alterations during experimental epileptic seizures in an animal model
Authors: Yorulmaz Hatice , Kaptan Engin , Seker F. Burcu , Oztas Baria
Published: May 2015

The aim of this study was to perform the effects of diabetes on the permeability of the blood–brain barrier (BBB) during pentylenetetrazole (PTZ)‐induced epileptic attacks. For this propose, the animals were divided into four groups. These groups contained were intact, PTZ‐treated, diabetic and PTZ‐treated diabetic individuals, respectively. To evaluate the functioning of the BBB, Evans blue was used as a BBB permeability indicator, and the expressions of zonula occludens‐1 and glial fibrillary acidic protein involving the functioning of the BBB were determined immunohistochemically. Also, the changes in the release of serum tumour necrosis factor‐alpha and interleukin‐10 and interleukin‐12 were studied by using enzyme‐linked immunosorbent assay method. BBB permeability in the seizures under diabetic conditions showed a considerable increase (p < 0·01) in all of the brain we studied. The immunoreactive staining intensity of zonula occludens‐1 and glial fibrillary acidic protein was found reduced in the brain regions of diabetic rats (p < 0·01). However, the serum level of tumour necrosis factor‐alpha increased in diabetes and diabetes + PTZ groups, and the serum level of interleukin‐12 increased significantly in all experimental groups (p < 0·05). In conclusion, diabetes dramatically increases BBB damage during epileptic seizures, and it may be derived from an elevation of paracellular passage. Copyright © 2015 John Wiley & Sons, Ltd.
Palladium and Bimetallic Palladium–Nickel Nanoparticles Supported on Multiwalled Carbon Nanotubes: Application to CarbonCarbon Bond‐Forming Reactions in Water
Authors: Ohtaka Atsushi , Sansano José M. , Nájera Carmen , Miguel‐García Izaskun , Berenguer‐Murcia Ángel , Cazorla‐Amorós Diego
Published: May 2015

Palladium and bimetallic Pd–Ni nanoparticles (NPs) protected by polyvinylpyrrolidone were prepared by the reduction‐by‐solvent method and deposited on multiwalled carbon nanotubes (MWCNTs). The catalytic activity of these NPs to carbon–carbon bond‐forming reactions was studied by using 0.1 mol % Pd loading, at 120 °C for 1 h and water as a solvent under ligand‐free conditions. The Suzuki–Miyaura reaction took place quantitatively for the cross‐coupling of 4‐bromoanisole with phenylboronic acid, better than those obtained with potassium phenyltrifluoroborate, with Pd50Ni50/MWCNTs as a catalyst and K2CO3 as a base and TBAB as an additive, with good recyclability during 4 cycles with some Ni leaching. The Hiyama reaction of 4‐iodoanisole with trimethoxyphenylsilane, under fluoride‐free conditions using 50 % aqueous NaOH solution, was performed with Pd/MWCNTs as a catalyst in 83 % yield with low recyclability. For the Mizoroki‐Heck reaction 4‐iodoanisole and styrene gave the corresponding 4‐methoxystilbene quantitatively with Pd50Ni50/MWCNTs using K2CO3 as a base and TBAB as an additive although the recycle failed. In the case of the Sonogashira‐Hagihara reaction, Pd/MWCNTs had to be used as a catalyst and pyrrolidine as a base for the coupling of 4‐iodoanisole with phenylacetylene under copper‐free conditions. The corresponding 4‐methoxytolane was quantitatively obtained allowing the recycling of the catalyst during 3 cycles.
Ecosystem recharge by volcanic dust drives broad‐scale variation in bird abundance
Authors: Gunnarsson Tómas Grétar , Arnalds Ólafur , Appleton Graham , Méndez Verónica , Gill Jennifer A.
Published: May 2015

Across the globe, deserts and volcanic eruptions produce large volumes of atmospheric dust, and the amount of dust is predicted to increase with global warming. The effects of long‐distance airborne dust inputs on ecosystem productivity are potentially far‐reaching but have primarily been measured in soil and plants. Airborne dust could also drive distribution and abundance at higher trophic levels, but opportunities to explore these relationships are rare. Here we use Iceland's steep dust deposition gradients to assess the influence of dust on the distribution and abundance of internationally important ground‐nesting bird populations. Surveys of the abundance of breeding birds at 729 locations throughout lowland Iceland were used to explore the influence of dust deposition on bird abundance in agricultural, dry, and wet habitats. Dust deposition had a strong positive effect on bird abundance across Iceland in dry and wet habitats, but not in agricultural land where nutrient levels are managed. The abundance of breeding waders, the dominant group of terrestrial birds in Iceland, tripled on average between the lowest and highest dust deposition classes in both wet and dry habitats. The deposition and redistribution of volcanic materials can have powerful impacts in terrestrial ecosystems and can be a major driver of the abundance of higher trophic‐level organisms at broad spatial scales. The impacts of volcanic ash deposition during eruptions and subsequent redistribution of unstable volcanic materials are strong enough to override effects of underlying variation in organic matter and clay content on ecosystem fertility. Global rates of atmospheric dust deposition are likely to increase with increasing desertification and glacier retreat, and this study demonstrates that the effects on ecosystems are likely to be far‐reaching, both in terms of spatial scales and ecosystem components.
Invasive plants may promote predator‐mediated feedback that inhibits further invasion
Authors: Smith Lauren M. , Schmitz Oswald J.
Published: May 2015

Understanding the impacts of invasive species requires placing invasion within a full community context. Plant invaders are often considered in the context of herbivores that may drive invasion by avoiding invaders while consuming natives (enemy escape), or inhibit invasion by consuming invaders (biotic resistance). However, predators that attack those herbivores are rarely considered as major players in invasion. Invasive plants often promote predators, generally by providing improved habitat. Here, we show that predator‐promoting invaders may initiate a negative feedback loop that inhibits invasion. By enabling top‐down control of herbivores, predator‐promoting invaders lose any advantage gained through enemy escape, indirectly favoring natives. In cases where palatable invaders encounter biotic resistance, predator promotion may allow an invader to persist, but not dominate. Overall, results indicate that placing invaders in a full community context may reveal reduced impacts of invaders compared to expectations based on simple plant–plant or plant–herbivore subsystems.