bluuebunny/crossref_metadata_2025 huggingface dataset:
A generalized CAD model for the full‐wave modeling of Coplanar striplines discontinuities
Authors: Laib S. , Djahli F. , Mayouf A. , Carru J.‐C. , Devers T.
Published: March 2011

In this work, the coplanar stripline (CPS) and its discontinuities: open‐end, short‐end, gaps and resonator have been modeled. New integral equations for the electrical field components are formulated, in the spectral domain, using an exact dyadic Green's function, applied to the CPS structure. The use of this form of Green's function allows the consideration of the effects of the dielectric losses, the surface wave excitation and the space wave radiation on the propagation characteristics of the CPS and its discontinuities. The resulting integral equation has been solved using the two‐dimensional Galerkin's technique. The resolution of the resulting matrix equation gives the scattering parameters of the studied structures. The obtained results are commented and compared with those of other approaches and measurements. Copyright © 2011 John Wiley & Sons, Ltd.
The Effects of Process Engineering on the Performance of PLA and PHBV Blends
Authors: Nanda Malaya R. , Misra Manjusri , Mohanty Amar K.
Published: March 2011

The effects of process engineering in the fabrication of PHBV, PLA and their blends prepared by melt blending are studied. The elongation of an optimized blend can be improved by 148 and 250% over the virgin PHBV and PLA polymers, respectively. DSC shows that the two polymers are immiscible in blends of any composition. The crystallinity of PHBV is hindered by the presence of PLA. UV‐Vis demonstrates the opacity of the blend with incorporation of PHBV to the PLA phase. The observed tensile modulus of the optimized sample is compared with theoretical values from the rule of mixtures. Gordon‐Taylor's equation is applied on the glass transition temperatures for theoretical modeling to explain the miscibility of the polymers.

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Strain‐dependent T1 relaxation profiles in articular cartilage by MRI at microscopic resolutions
Authors: Xia Yang , Wang Nian , Lee Jihyun , Badar Farid
Published: March 2011

To investigate the dependency of T1 relaxation on mechanical strain in articular cartilage, quantitative magnetic resonance T1 imaging experiments were carried out on cartilage before/after the tissue was immersed in gadolinium contrast agent and when the tissue was being compressed (up to ∼48% strains). The spatial resolution across the cartilage depth was 17.6 μm. The T1 profile in native tissue (without the presence of gadolinium ions) was strongly strain‐dependent, which is also depth‐dependent. At the modest strains (e.g., 14% strain), T1 reduced by up to 68% in the most surface portion of the tissue. Further compression (e.g., 45% strain) reduced T1 mostly in the middle and deep portions of the tissue. For the gadolinium‐immersed tissue, both modest and heavy compressions (up to 48% strain) increased T1 slightly but significantly, although the overall shapes of the T1 profiles remained approximately the same regardless of the amount of strains. The complex relationships between the T1 profiles and the mechanical strains were a direct consequence of the depth‐dependent proteoglycan concentration in the tissue, which determined the tissue's mechanical properties. This finding has potential implications in the use of gadolinium contrast agent in clinical magnetic resonance imaging of cartilage (the dGEMRIC procedure), when the loading or loading history of patients is considered. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Parameterization of planar curves immersed in triangulations with application to finite elements
Authors: Rangarajan Ramsharan , Lew Adrian J.
Published: March 2011

We construct a method for the parameterization of a class of planar piecewise C2‐curves over a collection of edges in an ambient triangulation. The map from the collection of edges to the curve is the closest‐point projection. A distinguishing feature of the method is that edges in the ambient triangulation need not interpolate the curve. We formulate conditions on the ambient triangulations so that the resulting parameterization over its selected edges is (i) bijective, (ii) maps simple, connected collection of edges to simple, connected components of the curve, and (iii) is C1 within each edge of the collection. These properties of the parameterization make it particularly useful in the construction of high‐order finite element approximation spaces on planar curves immersed in triangulations. We discuss this application and illustrate it with numerical examples.

The parameterization method applies to a large class of planar curves, including most ones of interest in engineering and computer graphics applications, and to a large family of triangulations, including acute‐angled triangulations. Copyright © 2011 John Wiley & Sons, Ltd.
UK trading: A guide to charities and the tax implications
Authors: Brooks Nicholas
Published: March 2011

Due to the recession, the National Lottery and the increase in numbers of charities seeking funds to satisfy their objectives, charities are moving into new areas of fundraising which undoubtedly are leading towards the increasing role of trading. What this paper hopes to achieve is to define trading, discuss some of the major types of trading and their taxation aspects, and to point out some of the pitfalls and how they might be overcome.
Charity box collection schemes: The retailers' view
Authors: Horne Suzanne , Moss Michael
Published: March 2011

Most UK charities, both national and local, place boxes in outlets such as shops, bars, cafés, filling stations, banks and building societies. Usually the box is placed by a representative of the charity visiting the potential site and inviting whoever is on duty to accept the box. This research sampled 2,308 UK retailers in order to determine their perceptions of the boxes held on their premises, the number of boxes held, their location and security. From the responses to the survey the authors discuss the distribution of boxes over different retail types and analyse retailers perceptions.
Religious coping and behavioral disengagement: opposing influences on advance care planning and receipt of intensive care near death
Authors: Maciejewski Paul K. , Phelps Andrea C. , Kacel Elizabeth L. , Balboni Tracy A. , Balboni Michael , Wright Alexi A. , Pirl William , Prigerson Holly G.
Published: March 2011

Objective: This study examines the relationships between methods of coping with advanced cancer, completion of advance care directives, and receipt of intensive, life‐prolonging care near death.

Methods: The analysis is based on a sample of 345 patients interviewed between January 1, 2003, and August 31, 2007, and followed until death as part of the Coping with Cancer Study, an NCI/NIMH‐funded, multi‐site, prospective, longitudinal, cohort study of patients with advanced cancer. The Brief COPE was used to assess active coping, use of emotional‐support, and behavioral disengagement. The Brief RCOPE was used to assess positive and negative religious coping. The main outcome was intensive, life‐prolonging care near death, defined as receipt of ventilation or resuscitation in the last week of life.

Results: Positive religious coping was associated with lower rates of having a living will (AOR = 0.39, p = 0.003) and predicted higher rates of intensive, life‐prolonging care near death (AOR, 5.43; p<0.001), adjusting for other coping methods and potential socio‐demographic and health status confounds. Behavioral disengagement was associated with higher rates of DNR order completion (AOR, 2.78; p = 0.003) and predicted lower rates of intensive life‐prolonging care near death (AOR, 0.20; p = 0.036). Not having a living will partially mediate the influence of positive religious coping on receipt of intensive, life‐prolonging care near death.

Conclusion: Positive religious coping and behavioral disengagement are important determinants of completion of advance care directives and receipt of intensive, life‐prolonging care near death. Copyright © 2011 John Wiley & Sons, Ltd.
Equivalent Elevation: A New Method to Incorporate Variable Surface Lapse Rates into Mountain Permafrost Modelling
Authors: Lewkowicz Antoni G. , Bonnaventure Philip P.
Published: March 2011

Permafrost is present at multiple elevations with no defined lower limit in the southern Yukon Territory, Canada. Empirical statistical modelling of permafrost probability in the region required the development of equivalent elevation, a new variable that reflects measured differences between surface air temperature lapse rates below and above treeline. In areas where surface lapse rates are negative (normal) but gentle up to the altitudinal treeline, equivalent elevation results in a compressed elevational range. Where surface lapse rates are positive (inverted) in the forest due to the strength of winter inversions, equivalent elevations calculated for valley floors are higher than those at treeline. There is a strong relationship between the magnitude and sign of surface lapse rates below treeline and the annual amplitude of monthly air temperatures at nearby climate stations, which permits prediction of equivalent elevation for the entire region. Permafrost probability modelling using equivalent elevation produced statistically significant results in several study areas whereas actual elevation values did not. The concept is of particular use where forested areas are underlain by permafrost and may be transferable to areas with similar terrain and climate such as those in the Canadian Northwest Territories, Alaska and Mongolia. Copyright © 2011 John Wiley & Sons, Ltd.
Area‐wide management of Aedes albopictus: choice of study sites based on geospatial characteristics, socioeconomic factors and mosquito populations
Authors: Unlu Isik , Farajollahi Ary , Healy Sean P , Crepeau Taryn , Bartlett‐Healy Kristen , Williges Eric , Strickman Daniel , Clark Gary G , Gaugler Randy , Fonseca Dina M
Published: March 2011

BACKGROUND: Aedes (Stegomyia) albopictus (Skuse), the Asian tiger mosquito, is an introduced invasive species in the United States that is responsible for a significant proportion of service requests to local mosquito control programs. This container‐utilizing mosquito is refractory to standard mosquito abatement measures in the United States. This study is part of a USDA‐ARS project to develop an area‐wide management strategy for Ae. albopictus. The goal was to identify three study sites, similar in socioeconomic parameters, geography and Ae. albopictus abundance, in urban and suburban areas in Mercer and Monmouth counties in New Jersey. Prior service requests and light trap counts and also detailed county maps were used to chose nine preliminary sites (four in Mercer and five in Monmouth) where weekly surveillance for Ae. albopictus was performed throughout the 2008 active season.

RESULTS: Although outliers were detected, socioeconomic variables in the study sites within each county were fairly consistent. Ae. albopictus abundance was associated with poverty levels and had the highest maxima in Mercer, although average mosquito abundance was similar in urban Mercer and suburban Monmouth.

CONCLUSION: Three study sites in each county were identified for future studies. The summer‐long surveillance also revealed socioeconomic variables critical for the development of integrated mosquito management. Copyright © 2011 Society of Chemical Industry
An assessment of a mountain‐wave parametrization scheme using satellite observations of stratospheric gravity waves
Authors: Wells H. , Vosper S. B. , Yan X.
Published: March 2011

Gravity‐wave‐induced temperature fluctuations predicted by a mountain‐wave parametrization scheme are compared with observed stratospheric temperature fluctuations from the High‐Resolution Dynamics Limb Sounder (HIRDLS) instrument. The focus of the study is on the southern Andes region during the month of August 2006. The comparison reveals that while the mean amplitude of temperature fluctuations predicted by the parametrization is broadly consistent with those observed by HIRDLS, there are significant differences for individual cases. Ray‐tracing calculations performed for these cases suggest that these differences are likely to be associated with horizontal propagation of mountain waves, which is not represented by current column‐based parametrization schemes. The results presented in this note suggest that this is a deficiency of mountain‐wave parametrization schemes that may affect models at resolutions typical of both climate and numerical weather prediction modelling. Copyright © 2011 Royal Meteorological Society and British Crown Copyright, the Met Office
Robust track‐and‐trace video watermarking
Authors: Yang Lei , Chen Qian , Tian Jun , Wu Dapeng
Published: March 2011

With the development of computers and the Internet, digital multimedia can be distributed and pirated easily. Watermarking is a useful technique for multimedia copyright protection. In this paper, we develop a robust video watermarking system. It consists of two components, that is, watermarking embedder and watermarking detector. In the embedder, we insert a watermark pattern into video frames according to a watermark payload. The watermark pattern is generated from a pseudo‐random noise sequence generator using the spread spectrum technique. User and copyright information are mapped to a binary sequence and then encrypted with advanced encryption standard and encoded/protected by convolutional error correction code to produce a watermark payload. The watermark pattern is weighted and embedded to each frame to meet perceptual requirements. In addition, the video is slightly geometrically manipulated in order to defend possible collusion attacks. The detector extracts the watermark from the candidate video. Kanade–Lucas–Tomasi feature tracker is used to register the candidate video with respect to the original video to enhance the correlation with the reference. The cross‐correlation sequence is binarized, error correction code decoded, and decrypted. The experimental results show that the proposed video watermark system is very robust to not only geometric attack but also collusion attacks, and that it is perceptually invisible to human vision system. Copyright © 2011 John Wiley & Sons, Ltd.
Generation mechanism of electrochemical migration in printed wiring board insulation
Authors: Natsui Masashi , Asakawa Hiroki , Tanaka Toshikatsu , Ohki Yoshimichi , Maeno Takashi , Okamoto Kenji
Published: March 2011

In order to study the generation mechanism of electrochemical migration in a printed wiring board, paper/phenol‐resin composites with and without an adhesive layer, epoxy resin, and a laminate of epoxy resin and a paper/phenol‐resin composite were aged at 85 °C and 85% relative humidity (RH) with and without application of a DC voltage, and the space charge distributions in the samples were observed by the pulsed electroacoustic method. In the case of the composite with the adhesive layer, a large amount of negative charge is induced at the interface between the composite and the adhesive layer on the anode. It was found that such formation of space charge enhances the electric field intensity at the anode. The reason for this is because the conductivity is much lower in the adhesive layer than in the composite. Electrochemical migration does not occur when the same electric field is applied to the composite without the adhesive layer, whereas it does occur if the adhesive layer was replaced by epoxy resin with a similar conductivity to the adhesive layer. These results clearly indicate that electrochemical migration generates because the electric field at the anode surface is enhanced due to the low conductivity of the adhesive layer. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
The need to pursue and publish clinical trials in nanomedicine
Authors: Baker James R.
Published: March 2011

This article is categorized under:

Therapeutic Approaches and Drug Discovery > Emerging Technologies
tRNA mimicry in translation termination and beyond
Authors: Nakamura Yoshikazu , Ito Koichi
Published: March 2011

The mechanism of translation termination has long been a puzzle. The release factor (RF) class of translation factors plays a key role in terminating protein synthesis. Bacteria have two RFs, RF1 and RF2, with high specificity to decipher three stop codons. Decades ago, an idea was formulated that RFs may be protein analogs of tRNA. This idea gained substantial support 10 years ago by the identification of two classes of crucial RF peptide motifs, P(A/V)T/SPF and GGQ, in bacteria. These motifs were functionally equivalent to the anticodon and aminoacyl‐CCA terminus of tRNA, although the processes these molecules function in are different. These findings reinforced the ‘molecular mimicry’ or ‘tRNA mimicry’ hypothesis. Since then, the RF‐tRNA mimicry hypothesis has played a crucial role to elucidate the mechanism of translation termination. In the past decade, the crystal structure of the translation termination complex between the ribosome and RFs has been determined at atomic resolution. Overall, the structural data strongly support the RF‐tRNA mimicry hypothesis, with shared as well as distinct ribosomal conformations induced by RF or tRNA binding. In this review, we re‐evaluate the structural data from the genetic and biochemical viewpoint as our initial functional evidence were not fully interpreted in the previous reports. Recent structural and functional studies of the translation machinery have uncovered that the concept of tRNA mimicry can be expanded for factors beyond translation termination and into translation initiation, elongation, as well as mRNA surveillance pathways for protein synthesis. WIREs RNA 2011 2 647–668 DOI: 10.1002/wrna.81

This article is categorized under:

RNA Interactions with Proteins and Other Molecules > RNA–Protein Complexes

Translation > Ribosome Structure/Function

Translation > Translation Regulation

RNA Processing > tRNA Processing
Characteristics of road‐kill locations of San Clemente Island foxes
Authors: Snow Nathan P. , Andelt William F. , Gould Nicholas P.
Published: March 2011

Mortalities from collisions with vehicles have created concern for the welfare of the San Clemente Island fox (Urocyon littoralis clementae); 1 of only 6 genetically distinct subspecies of island fox. To find possible solutions for minimizing these mortalities, we compared 9 characteristics of roads and roadsides at kill‐sites and control‐sites to ascertain whether certain features were associated with risk of collisions. We found that kill‐sites were positively associated with the volume of traffic, and negatively associated with the distance of motorists' visibility, which had not been previously identified for island foxes. Additionally, visual obstructions along roadsides (i.e., steep ditches and tall vegetation) showed some evidence of increasing mortalities. We also found that gravel mounds, a possible pseudo‐barrier along roadsides, were associated with reduced mortalities. Speeds of vehicles, presence of drainages, cacti, and culverts, and seasonality showed minimal effects on road‐kills. Our findings suggest that efforts to reduce mortalities should focus on roads with high volumes of traffic and high amounts of visual obstruction for motorists. Possible methods for reducing road‐kills include installing signs and speed bumps on curves of roads, regular mowing of roadsides, constructing gravel‐mound barriers along edges of roads, and educating motorists. © 2011 The Wildlife Society.
The Antler Religion
Authors: Matt Knox W.
Published: March 2011

Intensive deer management characterized by high fences and supplemental feeding and, in some instances, selective breeding programs, has increased dramatically across North America (NA) over the past several decades. This new management philosophy is not, however, without controversy. At several levels intensive deer management is incompatible with the NA Model of Wildlife Conservation including the fact that it promotes the privatization of wildlife and creates markets that sell public wildlife resources. Lastly, deer “hunting” under the intensive deer‐management model violates the fundamental concept of fair chase, which is a cornerstone principle of hunting in NA. © 2011 The Wildlife Society.
An online Fisheries and Wildlife degree: Can you really do that?
Authors: Edge W. Daniel , Sanchez Dana
Published: March 2011

Online education has moved into the mainstream in the United States higher learning educational system, with enrollments increasing more rapidly than on many university campuses. The Department of Fisheries and Wildlife at Oregon State University began offering a Bachelor of Science (BS) Degree in Fisheries and Wildlife Science (FWS) completely online in autumn 2009, which resulted in numerous questions from potential students, educators, and fish and wildlife professionals. We provide an overview of our distance education (DE) degree and characterize our DE learners. The DE degree itself is the same as the on‐campus major but the curriculum is slightly different; online students have fewer choices in classes and hands‐on activities, but engage in more discussion than on‐campus students. Our DE students differ from on‐campus majors: they are on average 9 years older, 40% have a college degree, and 20% are employed by a natural resources agency. The value of our online FWS BS ultimately will be gauged by the success of our graduates and feedback from stakeholders. © 2011 The Wildlife Society.
Higher-order singular multi-point boundary-value problems on time scales
Authors: Dogan Abdulkadir , Graef John R. , Kong Lingju
Published: March 2011

We study classes of higher-order singular boundary-value problems on a time scale $\mathbb{T}$ with a positive parameter λ in the differential equations. A homeomorphism and homomorphism ø are involved both in the differential equation and in the boundary conditions. Criteria are obtained for the existence and uniqueness of positive solutions. The dependence of positive solutions on the parameter λ is studied. Applications of our results to special problems are also discussed. Our analysis mainly relies on the mixed monotone operator theory. The results here are new, even in the cases of second-order differential and difference equations.
THE IMPACT OF CHILDHOOD MALNUTRITION ON SCHOOLING: EVIDENCE FROM BANGLADESH
Authors: KHANAM RASHEDA , NGHIEM HONG SON , RAHMAN MOHAMMAD MAFIZUR
Published: March 2011

This paper examines the impact of childhood malnutrition on schooling performance in rural Bangladesh. The results reveal that malnourished children are less likely to enrol in school on time and achieve an age-appropriate grade by 26 percentage points and 31 percentage points, respectively. Other important determinants of schooling outcomes include infrastructure and education level of parents. One major contribution of this paper is the control for the endogeneity of malnutrition status, which otherwise might lead to bias estimates.
Stirring, stretching and transport generated by a pair of like-signed vortices
Authors: RIZZI F. , CORTELEZZI L.
Published: March 2011

We consider a pair of like-signed, initially elliptical vortices with uniform vorticity distribution embedded in an incompressible, inviscid fluid occupying a two-dimensional, infinite domain. We characterize this finite-time, aperiodic, dynamical system in terms of its fixed points and separatrices, which divide the flow into inner core, inner recirculation, outer recirculation regions and outer flow. We numerically simulate the time evolution of the vortex pair using a contour dynamics algorithm. The rotational and co-rotational motion of the vortices perturb the separatrices, which undergo to deformations, yielding a tangle whose complexity increases as the amplitude of the perturbation increases. We analyse the dynamics of the tangle and explain the transport of fluid between different regions. We use two diagnostics to quantify stirring: stretching of the interface and the mix-norm. These two diagnostics characterize stirring in contradicting ways and present different sensitivity to the parameters considered. We find that stretching is dominated by the chaotic advection induced within the inner core and inner recirculation regions, whereas the mix-norm is dominated by the laminar transport induced within the outer recirculation regions. For pairs of vortices of small aspect ratio, stretching is piecewise linear and the mix-norm does not decrease monotonically. We show that these two effects are strongly coupled and synchronized with the rotational motion of the vortices. Since the nominal domain is unbounded, we quantify stirring on three concentric, circular domains. One domain nearly encloses the outer separatrices of the vortex pair, one is smaller and one larger than the first one. We show that the mix-norm is very sensitive to the size of the domain, while stretching is not. To quantify the sensitivity of stirring to the geometry of the initial concentration field, we consider, as an initial scalar field, two concentrations delimited by a straight-line interface of adjustable orientation. We show that the interface passing through the centroids of the vortices is the one most efficiently stretched, while the initial concentration field with an orthogonal interface is the most efficiently stirred. Finally, we investigate the effects of the angular impulse on the stirring performance of the vortex pair. Stretching is very sensitive to the angular impulse, while the mix-norm is not. We show that there is a value of the angular impulse which maximizes stretching and argue that this is due to two competing mechanisms.
Nutrition in an ethnically diverse society: what are some of the key challenges?
Authors: Szczepura Ala
Published: March 2011

The role of nutrition is especially important in certain ‘lifestyle’ diseases that impact disproportionately on ethnic minority populations. The aim of this paper is to review the evidence of risk, health outcomes and interventions for certain diseases that affect the UK's largest ethnic minority group (South Asians) in order to help professionals better address the needs of this diverse population. Research evidence is presented on factors influencing access to services by ethnic minority populations and the changing UK policy background for public health and preventive care. The available research base on obesity, diabetes and CVD is discussed. Conditions such as type 2 diabetes, which are more prevalent among the South Asian population, are associated with poorer health outcomes and appear to exhibit links to diet and nutrition that start in childhood or even before birth; all making preventive care important. Obesity is a major risk factor and it appears that BMI thresholds may need to be lower for South Asians. Targeted interventions to improve diet and outcomes in the South Asian population also appear promising. Recent moves to promote access to evidence of ethnicity and health and to improve the cultural competence of organisations are discussed. Health professionals will increasingly need to promote lifestyle changes in a manner that meets the needs of a diverse population in order to address future public health challenges. Nutritionists and other professionals will need to ensure that interventions are culturally appropriate and involve engagement with extended family members and communities.
D-type iterative learning control without resetting condition for robot manipulators
Authors: Bouakrif Farah
Published: March 2011

This paper deals with iterative learning control (ILC) design to solve the trajectory tracking problem for rigid robot manipulators subject to external disturbances, and performing repetitive tasks. A D-type ILC is presented with an initial condition algorithm, which gives the initial state value in each iteration automatically. Thus, the resetting condition (the initial state error is equal to zero) is not required. The λ-norm is adopted as the topological measure in our proof of the asymptotic stability of this control scheme, over the whole finite time-interval, when the iteration number tends to infinity. Simulation results are presented to illustrate the effectiveness of the proposed control scheme.
Task shifting in maternal and child health care: An evidence brief for Uganda
Authors: Nabudere Harriet , Asiimwe Delius , Mijumbi Rhona
Published: March 2011

The Problem: There is a shortage and maldistribution of medically trained health professionals to deliver cost-effective maternal and child health (MCH) services. Hence, cost-effective MCH services are not available to over half the population of Uganda and progress toward the Millennium Development Goals for MCH is slow. Optimizing the roles of less specialized health workers (“task shifting”) is one strategy to address the shortage and maldistribution of more specialized health professionals.

Policy Options: (i) Lay health workers (community health workers) may reduce morbidity and mortality in children under five and neonates; and training for traditional birth attendants may improve perinatal outcomes and appropriate referrals. (ii) Nursing assistants in facilities might increase the time available from nurses, midwives, and doctors to provide care that requires more training. (iii) Nurses and midwives to deliver cost-effective MCH interventions in areas where there is a shortage of doctors. (iv) Drug dispensers to promote and deliver cost-effective MCH interventions and improve the quality of the services they provide. The costs and cost-effectiveness of all four options are uncertain. Given the limitations of the currently available evidence, rigorous evaluation and monitoring of resource use and activities is warranted for all four options.

Implementation Strategies: A clear policy on optimizing health worker roles. Community mobilization and reduction of out-of-pocket costs to improve mothers’ knowledge and care-seeking behaviors, continuing education, and incentives to ensure health workers are competent and motivated, and community referral and transport schemes for MCH care are needed.
The representational adequacy of Hybrid
Authors: CROLE R. L.
Published: March 2011

The Hybrid system (Ambler et al. 2002b), implemented within Isabelle/HOL, allows object logics to be represented using higher order abstract syntax (HOAS), and reasoned about using tactical theorem proving in general, and principles of (co)induction in particular. The form of HOAS provided by Hybrid is essentially a lambda calculus with constants.

Of fundamental interest is the form of the lambda abstractions provided by Hybrid. The user has the convenience of writing lambda abstractions using names for the binding variables. However, each abstraction is actually a definition of a de Bruijn expression, and Hybrid can unwind the user's abstractions (written with names) to machine friendly de Bruijn expressions (without names). In this sense the formal system contains a hybrid of named and nameless bound variable notation.

In this paper, we present a formal theory in a logical framework, which can be viewed as a model of core Hybrid, and state and prove that the model is representationally adequate for HOAS. In particular, it is the canonical translation function from λ-expressions to Hybrid that witnesses adequacy. We also prove two results that characterise how Hybrid represents certain classes of λ-expression.

We provide the first detailed proof to be published that proper locally nameless de Bruijn expressions and α-equivalence classes of λ-expressions are in bijective correspondence. This result is presented as a form of de Bruijn representational adequacy, and is a key component of the proof of Hybrid adequacy.

The Hybrid system contains a number of different syntactic classes of expression, and associated abstraction mechanisms. Hence, this paper also aims to provide a self-contained theoretical introduction to both the syntax and key ideas of the system. Although this paper will be of considerable interest to those who wish to work with Hybrid in Isabelle/HOL, a background in automated theorem proving is not essential.
Traumafokussierte kognitive Verhaltenstherapie (Tf-KVT) bei Kindern und Jugendlichen nach Missbrauch und Misshandlung
Authors: Kirsch Veronica , Fegert Jörg M. , Seitz Diana C. M. , Goldbeck Lutz
Published: March 2011

Posttraumatische Belastungsstörungen (PTBS) sind eine häufige Folge von Missbrauch und Misshandlung im Kindes- und Jugendalter. Die Wirksamkeit der traumafokussierten kognitiven Verhaltenstherapie (Tf-KVT) nach sexuellem Missbrauch ist gut belegt. Diese Pilotstudie untersucht Machbarkeit und Behandlungsergebnisse bei Patienten mit posttraumatischen Stresssymptomen nach unterschiedlichen Misshandlungsformen und häuslicher Gewalt. 15 Kinder und Jugendliche mit klinisch relevanten PTBS Symptomen (sechs weiblich; Alter M = 10.5; SD = 3.7) wurden mit 12 bis 31 Sitzungen Tf-KVT behandelt. Die Symptomatik wurde im prä-post-Vergleich analysiert. Die Hintergründe von drei Therapieabbrüchen wurden ermittelt. Die Tf-KVT führte zu einer signifikanten Symptomreduktion (Gesamtrohwert im Interview für Belastungsstörungen vor Therapie: 40.6; SD = 10.5; nach Therapie: M = 15.2; SD = 14.3; p < .001; d = 1.8). Der Grund für Therapieabbrüche war Vermeidungsverhalten bei psychisch belasteten Bezugspersonen. Die Ergebnisse können als Hinweis für die Wirksamkeit der Tf-KVT bei Kindern und Jugendlichen mit PTBS nach unterschiedlichen Misshandlungsformen gewertet werden. Die Therapie setzt die psychosoziale Stabilität von Patienten und Bezugspersonen voraus.
Spatial downscaling of precipitation from GCMs for climate change projections using random cascades: A case study in Italy
Authors: Groppelli B. , Bocchiola D. , Rosso R.
Published: March 2011

We present a Stochastic Space Random Cascade (SSRC) approach to downscale precipitation from a General Circulation Models (GCMs), developed for the assessment of water resources under climate change scenarios for the Oglio river (1440 km2), in the Italian Alps. The snow‐fed Oglio river displays complex physiography and high environmental gradient and statistical downscaling methods are required for climate change assessment. First, a back cast analysis is carried out to evaluate the most representative within a set of four available GCMs (R30, ECHAM4, PCM, HadCM3). Monthly precipitation for the window 1990–2000 from 270 gauging stations (one every 25 km2) in northern Italy is used and scores from objective indicators are calculated. The SSRC model is then tuned upon the Oglio river catchment for spatial downscaling (2 km2) of daily precipitation from the NCAR Parallel Climate Model, giving the comparatively best results for the area. Scale Recursive Estimation coupled with the Expectation Maximization algorithm is used for model estimation. The seasonal parameters of the multiplicative cascade are accommodated by statistical distributions conditioned upon the climatic forcing, based on a regression analysis. The SSRC approach reproduces well the spatial clustering, intermittency, self‐similarity, and spatial correlation structure of precipitation fields, with relatively low computational burden. Downscaling of future precipitation scenarios (A2 scenario from the Parallel Climate Model) is then carried out and some preliminary conclusions are drawn.
Hydrologic controls and anthropogenic drivers of the zebra mussel invasion of the Mississippi‐Missouri river system
Authors: Mari L. , Bertuzzo E. , Casagrandi R. , Gatto M. , Levin S. A. , Rodriguez‐Iturbe I. , Rinaldo A.
Published: March 2011

We propose a novel ecohydrological model for the invasion of inland waters by the zebra mussel Dreissena polymorpha and test it against field data gathered within the Mississippi‐Missouri river system in North America. This biological invasion poses major ecological and economic threats, especially due to the huge population densities reached by local zebra mussel colonies and the species' unparalleled dispersal abilities within fluvial systems. We focus on a quantitative evaluation, attempted here for the first time, of the individual roles and the mutual interactions of drivers and controls of the Mississippi‐Missouri invasion. To this end, we use a multilayer network model accounting explicitly for zebra mussel demographic dynamics, hydrologic transport, and dispersal due to anthropic activities. By testing our results against observations, we show that hydrologic transport alone is not sufficient to explain the spread of the species at the basin scale. We also quantify the role played by commercial navigation in promoting the initial, selective colonization of the river system, and show how recreational boating may have determined the capillary penetration of the species into the water system. The role of post‐establishment dispersal mechanisms and the effectiveness of possible prevention measures are also discussed in the context of model sensitivity and robustness to reparametrization.
Construction of direction selectivity in V1: from simple to complex cells
Authors: Lochmann Timm , Blanche Tim , Butts Daniel
Published: March 2011

Despite detailed knowledge about the anatomy and physiology of the primary visual cortex (V1), the immense number of feed-forward and recurrent connections onto a given V1 neuron make it difficult to understand how the physiological details relate to a given neuron’s functional properties. Here, we focus on a well-known functional property of many V1 complex cells: phase-invariant direction selectivity (DS). While the energy model explains its construction at the conceptual level, it remains unclear how the mathematical operations described in this model are implemented by cortical circuits. To understand how DS of complex cells is constructed in cortex, we apply a nonlinear modeling framework to extracellular data from macaque V1. We use a modification of spike-triggered covariance (STC) analysis to identify multiple biologically plausible "spatiotemporal features" that either excite or suppress a cell. We demonstrate that these features represent the true inputs to the neuron more accurately, and the resulting nonlinear model compactly describes how these inputs are combined to result in the functional properties of the cell. In a population of 59 neurons, we find that both simple and complex V1 cells are selective to combinations of excitatory and suppressive motion features. Because the strength of DS and simple/complex classification is well predicted by our models, we can use simulations with inputs matching thalamic and simple cells to assess how individual model components contribute to these measures. Our results unify experimental observations regarding the construction of DS from thalamic feed-forward inputs to V1: based on the differences between excitatory and inhibitory inputs, they suggest a connectivity diagram for simple and complex cells that sheds light on the mechanism underlying the DS of cortical cells. More generally, they illustrate how stage-wise nonlinear combination of multiple features gives rise to the processing of more abstract visual information.
The Taste of Music
Authors: Mesz Bruno , Trevisan Marcos A , Sigman Mariano
Published: March 2011

Zarlino, one of the most important music theorists of the XVI century, described the minor consonances as ‘sweet’ (dolci) and ‘soft’ (soavi) (Zarlino 1558/1983, in On the Modes New Haven, CT: Yale University Press, 1983). Hector Berlioz, in his Treatise on Modern Instrumentation and Orchestration (London: Novello, 1855), speaks about the ‘small acid-sweet voice’ of the oboe. In line with this tradition of describing musical concepts in terms of taste words, recent empirical studies have found reliable associations between taste perception and low-level sound and musical parameters, like pitch and phonetic features. Here we investigated whether taste words elicited consistent musical representations by asking trained musicians to improvise on the basis of the four canonical taste words: sweet, sour, bitter, and salty. Our results showed that, even in free improvisation, taste words elicited very reliable and consistent musical patterns: ‘bitter’ improvisations are low-pitched and legato (without interruption between notes), ‘salty’ improvisations are staccato (notes sharply detached from each other), ‘sour’ improvisations are high-pitched and dissonant, and ‘sweet’ improvisations are consonant, slow, and soft. Interestingly, projections of the improvisations of taste words to musical space (a vector space defined by relevant musical parameters) revealed that, in musical space, improvisations based on different taste words were nearly orthogonal or opposite. Decoding methods could classify binary choices of improvisations (ie identify the improvisation word from the melody) at performance of around 80%—well above chance. In a second experiment we investigated the mapping from perception of music to taste words. Fifty-seven non-musical experts listened to a fraction of the improvisations. We found that listeners classified with high performance the taste word which had elicited the improvisation. Our results, furthermore, show that associations of taste and music go beyond basic sensory attributes into the domain of semantics, and open a new venue of investigation to understand the origins of these consistent taste–musical patterns.
Species boundaries in Zausodes-complex species (Copepoda:Harpacticoida:Harpacticidae) from the north-eastern Gulf of Mexico
Authors: Easton Erin E. , Thistle David , Spears Trisha
Published: March 2011

Before 1999, the harpacticoid copepod species Zausodes arenicolus Wilson, 1932 was the subject of several ecological studies. Based on morphological evaluations of specimens from the north-eastern Gulf of Mexico, Bouck et al.’s (1999) taxonomic revision revealed three new species within what had been Z. arenicolus, making the ecological results suspect. Because harpacticoid copepods show convergent evolution and morphological stasis, Bouck et al.’s morphologically based approach may not have been sufficient. We have therefore re-evaluated their results using a combination of gene-sequencing and morphological methods. Partial mitochondrial cytochrome b (cytb) and 18S rRNA gene regions from individual Zausodes specimens found at five sites in the north-eastern Gulf of Mexico were separately analysed. Individuals of Zausodes septimus Lang, 1965 formed a single cytb gene-sequence clade, whereas Z. arenicolus individuals formed five. The uncorrected genetic divergences among these clades were 10 times those within them, providing evidence that each clade could be assigned to a different species. The 18S rDNA results support those from cytb. Subsequent morphological analysis revealed differences that will allow two clades of Z. arenicolus to be described as new species. Bouck et al. (1999) revealed some but not all of the species present.
A revision of the textricellin spider genus Raveniella (Araneae:Araneoidea:Micropholcommatidae): exploring patterns of phylogeny and biogeography in an Australian biodiversity hotspot
Authors: Rix Michael G. , Harvey Mark S. , Roberts J. Dale
Published: March 2011

South-western Western Australia is a biodiversity hotspot, with high levels of local endemism and a rich but largely undescribed terrestrial invertebrate fauna. Very few phylogeographic studies have been undertaken on south-western Australian invertebrate taxa, and almost nothing is known about historical biogeographic or cladogenic processes, particularly on the relatively young, speciose Quaternary sand dune habitats of the Swan Coastal Plain. Phylogeographic and taxonomic patterns were studied in textricellin micropholcommatid spiders belonging to the genus Raveniella Rix & Harvey. The Micropholcommatidae is a family of small spiders with a widespread distribution in southern Western Australia, and most species are spatially restricted to refugial microhabitats. In total, 340 specimens of Raveniella were collected from 36 surveyed localities on the Swan Coastal Plain and 17 non-Swan Coastal Plain reference localities in south-western Western Australia. Fragments from three nuclear rRNA genes (5.8S, 18S and ITS2), and one mitochondrial protein-coding gene (COI) were used to infer the phylogeny of the genus Raveniella, and to examine phylogeographic patterns on the Swan Coastal Plain. Five new species of Raveniella are described from Western Australia (R. arenacea, sp. nov., R. cirrata, sp. nov., R. janineae, sp. nov., R. mucronata, sp. nov. and R. subcirrata, sp. nov.), along with a single new species from south-eastern Australia (R. apopsis, sp. nov.). Four species of Raveniella were found on the Swan Coastal Plain: two with broader distributions in the High Rainfall and Transitional Rainfall Zones (R. peckorum Rix & Harvey, R. cirrata); and two endemic to the Swan Coastal Plain, found only on the western-most Quindalup dunes (R. arenacea, R. subcirrata). Two coastally restricted species (R. subcirrata, R. janineae) were found to be morphologically cryptic but genetically highly distinct, with female specimens morphologically indistinguishable from their respective sister-taxa (R. cirrata and R. peckorum). The greater Perth region is an important biogeographic overlap zone for all four Swan Coastal Plain species, where the ranges of two endemic coastal species join the northern and south-western limits of the ranges of R. peckorum and R. cirrata, respectively. Most species of Raveniella were found to occupy long, highly autapomorphic molecular branches exhibiting little intraspecific variation, and an analysis of ITS2 rRNA secondary structures among different species of Raveniella revealed the presence of an extraordinary hypervariable helix, ranging from 31 to over 400 nucleotides in length.
Patterns of habitat affinity and Austral/Holarctic parallelism in dictynoid spiders (Araneae:Entelegynae)
Authors: Spagna Joseph C. , Crews Sarah C. , Gillespie Rosemary G.
Published: March 2011

The ability to survive in a terrestrial environment was a major evolutionary hurdle for animals that, once passed, allowed the diversification of most arthropod and vertebrate lineages. Return to a truly aquatic lifestyle has occurred only rarely among terrestrial lineages, and is generally associated with modifications of the respiratory system to conserve oxygen and allow extended periods of apnea. Among chelicerates, in particular spiders, where the circulatory system also serves as a hydrostatic skeleton, very few taxa have exploited aquatic environments, though these environments are abundant and range from freshwater ponds to the marine intertidal and relictual (salt) lakes. The traditional systematic positions of the taxa inhabiting these environments are controversial. Partitioned Bayesian analysis using a doublet model for stems in the nearly complete 18S rRNA gene (~1800 nt) and in the D2 and D3 regions of the 28S rRNA gene (~690 nt), and standard models for loops and full protein-coding histone H3 (349 nt) partitions (totalling 3133 bp when aligned) of dictynoid spiders and related lineages revealed that the only truly aquatic spider species, Argyroneta aquatica (Clerck, 1767) (Cybaeidae Banks, 1892), belongs in a clade containing other taxa with unusual habitat affinities related to an aquatic existence, including occupation of semi-aquatic (intertidal) areas (Desidae Pocock, 1985: Paratheuma spp.) and highly alkaline salt-crusts (Dictynidae O. Pickard-Cambridge, 1871: Saltonia incerta (Banks, 1898)). In a contrasting pattern, other spiders that also occupy intertidal zones, including some other members of the family Desidae (Desis spp., Badumna longinqua (L. Koch, 1867)), are an independently derived clade found primarily in the southern hemisphere. Use of the doublet model reduced some branch-support values in the single-gene trees for rRNA data, but resulted in a robust combined-data phylogeny from 18S rRNA, 28S rRNA, and histone H3. This combination of results – reduction in support in single-gene trees and gain in support in combined-data trees –is consistent with use of the doublet model reducing problematic signal from non-independent base pairs in individual data partitions, resulting in improved resolution in the combined-data analyses.