Bifurcated polarization rotation in bismuth-based piezoelectrics

ABO3 perovskite-type solid solutions display a large variety of structural and physical properties, which can be tuned by chemical composition or external parameters such as temperature, pressure, strain, electric, or magnetic fields. Some solid solutions show remarkably enhanced physical properties including colossal magnetoresistance or giant piezoelectricity. It has been recognized that structural distortions, competing on the local level, are key to understanding and tuning these remarkable properties, yet, it remains a challenge to experimentally observe such local structural details. Here, from neutron pair-distribution analysis, a temperature-dependent 3D atomic-level model of the lead-free piezoelectric perovskite Na0.5Bi0.5TiO3 (NBT) is reported. The statistical analysis of this model shows how local distortions compete, how this competition develops with temperature, and, in particular, how different polar displacements of Bi3+ cations coexist as a bifurcated polarization, highlighting the interest of Bi-based materials in the search for new lead-free piezoelectrics

In-Flight Evaluation of the Traffic Aware Planner on the NASA HU-25A Guardian Aircraft

NASAs Traffic Aware Planner (TAP) software is a research-prototype decision support tool that provides pilots with time- and fuel-saving route recommendations that optimize their current trajectory. The software runs on a first-of-a-kind system architecture onboard three aircraft in revenue service conducting operational evaluations with a major domestic airline. Therefore, significant NASA-internal testing is required prior to releasing the software to the partner airline. This paper describes a flight test plan that exercises the functionality of the TAP software in a representative operational environment, describes the system architecture developed and implemented for the NASA Langley HU-25A Guardian aircraft to support the test objectives, presents outcomes of the flight test campaign, and discusses use cases that demonstrate the value of flight testing for this activity.Research into flight path optimization of transport aircraft conducted by the National Aeronautics and SpaceAdministration (NASA) has produced an operational concept known as Traffic Aware Strategic Aircrew Requests(TASAR) [1, 2]. This near-term concept [3] provides the aircrew with a flight deck decision support tool known asthe Traffic Aware Planner (TAP). The TAP software leverages a growing number of information sources on the flightdeck to make time- and fuel-saving route optimization recommendations to the aircrew while en route. The aircrewcan then use the suggestions provided by the tool to make route change requests with a greater likelihood of acceptanceby air traffic control (ATC). Since TASAR is a concept intended for the current operational environment, it isintentionally designed to have no safety-critical impact or require any changes to current Federal AviationAdministration (FAA) rules and procedures [4, 5].The research prototype TAP system [68], explained further in Section III.C, continually incorporates up-to-dateaircraft state data from onboard avionics, as well as the latest position of surrounding traffic, the most recent windforecast, and the most recent convective weather forecast, in order to calculate candidate trajectory modifications thatimprove upon the current active route. These trajectories account for user-selectable objective functions [3] of reducedfuel burn, reduced flight time, or an airline-derived combination of factors known as trip cost. Previous analyses andsimulations have estimated substantial savings for airlines employing this technique within the U.S. National AirspaceSystem (NAS) [911]. Operational evaluations with Alaska Airlines seek to validate these projected benefits usingmeasured data while simultaneously providing benefits to the airline [12, 13].The TAP software has undergone a number of human-in-the-loop simulations [14] and flight test activities[1517] in order to validate the operational concept, evaluate human factors considerations (e.g., workload, usability,distraction, etc.), and to assess the ability of the software to function in a representative operational environment (e.g.,connected to live avionics data, using in-flight internet connectivity, etc.). However, these simulations and flight testcampaigns did not account for the hardware architecture implemented on the three aircraft for Alaska Airlinesoperational evaluations of the TAP software. Therefore, a need was identified to thoroughly test the functionality ofthe software in a similar hardware architecture to that of the partner airlines aircraft. Information regarding testapparatus and environments used to evaluate TAP prior to testing on the HU-25A can be found in reference [18].A campaign of flight trials on a NASA aircraft, the HU-25A Guardian, was conducted to ensure that the researchprototype TAP system functions well in a configuration similar to the Alaska Airlines aircraft prior to deployment.This airborne, networked environment enables an assessment of the operational factors unique to the flight environment. Additionally, this activity evaluated the effectiveness and benefit of new TAP functionality andoperation in a relevant flight environment while allowing the rapid prototyping of new concepts and features.This paper is organized as follows: Section II discusses the details of the flight test plan, flight profiles, and theduties of personnel involved with conducting flight operations. Section III describes the test platform, avionicsequipage, and system architecture. Section IV presents a discussion of results, and Section V contains concludingremarks

Simulation and Flight Test Environments for the TASAR Traffic Aware Planner

The Traffic Aware Planner (TAP) software is a flight deck decision support tool that enhances the flight crews ability to make flight-optimizing route change requests while airborne. The software provides conflict-free, optimized trajectory suggestions during en route flight to produce time- and fuel-savings compared to the current trajectory. The TAP software requires evaluation in an operational environment with real pilot users to validate projected benefits. To this end, a set of developmental test environments have been developed to mature the software and mitigate technical risk prior to entering operational evaluation. The unique attributes of each test environment were leveraged to provide a range of purpose- and case-dependent TAP software tests. This paper describes the elements of a testing environment, discusses several environments of varying fidelity used to test the TAP software, and provides a review of two case studies highlighting the vital role testing played in the TAP software development process

Securing tropical forest carbon: the contribution of protected areas to REDD

Forest loss and degradation in the tropics contribute 6-17% of all greenhouse gas emissions. Protected areas cover 217.2 million ha (19.6%) of the world's humid tropical forests and contain c. 70.3 petagrams of carbon (Pg C) in biomass and soil to 1 m depth. Between 2000 and 2005, we estimate that 1.75 million ha of forest were lost from protected areas in humid tropical forests, causing the emission of 0.25-0.33 Pg C. Protected areas lost about half as much carbon as the same area of unprotected forest. We estimate that the reduction of these carbon emissions from ongoing deforestation in protected sites in humid tropical forests could be valued at USD 6,200-7,400 million depending on the land use after clearance. This is >1.5 times the estimated spending on protected area management in these regions. Improving management of protected areas to retain forest cover better may be an important, although certainly not sufficient, component of an overall strategy for reducing emissions from deforestation and forest degradation (REDD

Pilot Study: HPV Infection Knowledge & HPV Vaccine Acceptance among Women Residing in Ciudad Juárez, México

The human papillomavirus (HPV) is one of the most common sexually transmitted infections (STI) in the world and it is associated with cervical cancer. The development of a prophylactic HPV vaccine has proven effective in clinical trials and it is now available to the public. The HPV vaccine represents a viable prevention strategy against cervical cancer. However, parental preferences, perceptions, and willingness to use the HPV vaccine are crucial, and if not assessed accurately, may threaten the successful implementation of a broad HPV vaccination program. This pilot study explored the views of 60 adult, Mexican women, all of who were mothers of female children between the ages of ten to 14 years old on the following four areas of interest: HPV knowledge; HPV vaccine knowledge and attitudes; barriers to HPV vaccine use; and potential uses and side effects of the HPV vaccine. Only 7% of respondents knew that HPV was a virus or STI. Eighty-six percent had not heard of the HPV vaccine, but 62% felt that the HPV vaccine would prevent HPV infection. However, 38% said the church would not approve of the HPV vaccine use for 10-14-year-old girls. Twenty-seven percent thought that promiscuous behavior would increase following HPV vaccination. Overall, respondents had very little knowledge of the HPV vaccine, were willing to be vaccinated themselves (83%), but were lesser willing to vaccinate their daughters (63%). Ultimately, understanding the beliefs about and identifying the barriers of HPV vaccine use will influence the effectiveness of the vaccine and its potential impact in reducing cervical cancer incidence rates worldwide

Discriminación por razón de género y negociación colectiva tras la ley 3/2012

Este artículo describe y analiza la configuración jurídica del convenio colectivo como fuente reguladora y ga-rantista del derecho de igualdad y no dis-criminación por razón de género, tanto con carácter general como en el ámbito específico del acceso al empleo, formación y promoción en el trabajo y en las más relevantes condiciones en las relaciones laborales. A tal fin, y a partir de la doctrina establecida por la jurisprudencia constitucional, se estudian las causas de la desigualdad y las categorías que permiten una fundamentación razonable y objetiva para lograr la igualdad material. También se aportan datos cuantitativos acerca de la influencia de la Ley Orgánica 3/2007 en el régimen de los convenios convenios colectivos en esta materia.This paper work de-scribes and analyses the collective agree-ments legal configuration as regulating and guarantor source of the equality's right and no discrimination because of the sex, as much in general terms as in the specific field of accessing to a job, training and advance-ment in the job and in the main conditions in the labour relationships. According the established doctrine by the constitutional sentences, we study the inequality causes and the categories which give a reasonable and factual basis to reach a material equality. In addition, this work also provides quanti-tative facts about the influence of Organic Law 3/2007 in the collective agreements regime in this matte

The molecular structure of gauche-1,3-butadiene: Experimental proof of non-planarity

International audienceThe planarity of the second stable conformer of 1,3-butadiene-the archetypal diene for the Diels-Alder reaction, in which a planar conjugated diene and a dienophile combine to form a ring-is not established. The most recent high level calculations predict the species to adopt a twisted, gauche structure due to steric interactions between the inner terminal hydrogens rather than a planar, cis structure favored by the conjugation of the doubled bonds. Here we unambiguously prove experimentally that the structure cis-1,3-butadiene is indeed gauche with a substantial dihedral angle of 34° , in excellent agreement with theory. Observation of two tunneling components indicates that the molecule undergoes facile interconversion between two equivalent enantiomeric forms. Comparison of experimentally determined structures for gauche-and trans-butadiene provides an opportunity to examine the effects of conjugation and steric interactions

Symbiotic Nitrogen Fixation and the Challenges to Its Extension to Nonlegumes

Access to fixed or available forms of nitrogen limits the productivity of crop plants and thus food production. Nitrogenous fertilizer production currently represents a significant expense for the efficient growth of various crops in the developed world. There are significant potential gains to be had from reducing dependence on nitrogenous fertilizers in agriculture in the developed world and in developing countries, and there is significant interest in research on biological nitrogen fixation and prospects for increasing its importance in an agricultural setting. Biological nitrogen fixation is the conversion of atmospheric N2 to NH3, a form that can be used by plants. However, the process is restricted to bacteria and archaea and does not occur in eukaryotes. Symbiotic nitrogen fixation is part of a mutualistic relationship in which plants provide a niche and fixed carbon to bacteria in exchange for fixed nitrogen. This process is restricted mainly to legumes in agricultural systems, and there is considerable interest in exploring whether similar symbioses can be developed in nonlegumes, which produce the bulk of human food. We are at a juncture at which the fundamental understanding of biological nitrogen fixation has matured to a level that we can think about engineering symbiotic relationships using synthetic biology approaches. This minireview highlights the fundamental advances in our understanding of biological nitrogen fixation in the context of a blueprint for expanding symbiotic nitrogen fixation to a greater diversity of crop plants through synthetic biology.Biotechnology and Biological Sciences Research Council (Great Britain) (Grants BB/L011484/1 and BB/L011476/1)National Science Foundation (U.S.) (Grant 1331098

Polydnavirus genomes reflect their dual roles as mutualists and pathogens

AbstractSymbionts often exhibit significant reductions in genome complexity while pathogens often exhibit increased complexity through acquisition and diversification of virulence determinants. A few organisms have evolved complex life cycles in which they interact as symbionts with one host and pathogens with another. How the predicted and opposing influences of symbiosis and pathogenesis affect genome evolution in such instances, however, is unclear. The Polydnaviridae is a family of double-stranded (ds) DNA viruses associated with parasitoid wasps that parasitize other insects. Polydnaviruses (PDVs) only replicate in wasps but infect and cause severe disease in parasitized hosts. This disease is essential for survival of the parasitoid's offspring. Thus, a true mutualism exists between PDVs and wasps as viral transmission depends on parasitoid survival and parasitoid survival depends on viral infection of the wasp's host. To investigate how life cycle and ancestry affect PDVs, we compared the genomes of Campoletis sonorensis ichnovirus (CsIV) and Microplitis demolitor bracovirus (MdBV). CsIV and MdBV have no direct common ancestor, yet their encapsidated genomes share several features including segmentation, diversification of virulence genes into families, and the absence of genes required for replication. In contrast, CsIV and MdBV share few genes expressed in parasitized hosts. We conclude that the similar organizational features of PDV genomes reflect their shared life cycle but that PDVs associated with ichneumonid and braconid wasps have likely evolved different strategies to cause disease in the wasp's host and promote parasitoid survival

Thermal and crystallization kinetics of yttrium-doped phosphate-based glasses

© 2019 The American Ceramic Society and Wiley Periodicals, Inc Yttrium-doped glasses have been utilized for biomedical applications such as radiotherapy, especially for liver cancer treatment. In this paper, the crystallization behavior of phosphate-based glasses doped with yttrium (in the system 45P2O5–(30 − x) Na2O–25CaO–xY2O3—where x = 0, 1, 3 and 5) have been investigated via Differential Scanning Calorimetry (DSC) using nonisothermal technique at different heating rates (5°C, 10°C, 15°C and 20°C/min). The glass compositions were characterized via EDX, XRD, Density and Molar volume analysis. The Moynihan and Kissinger methods were used for the determination of glass transition activation energy (Eg) which decreased from 192 to 118 kJ/mol (Moynihan) and 183 to 113 kJ/mol (Kissinger) with increasing yttrium oxide content. Incorporation of 0 to 5 mol% Y2O3 revealed an approximate decrease of 71 kJ/mol (Ozawa and Augis) for onset crystallization (Ex) and 26 kJ/mol (Kissinger) for crystallization peak activation energies (Ec). Avrami index (n) value analyzed via Matusita–Sakka equation suggested a one-dimensional crystal growth for the glasses investigated. SEM analysis explored the crystalline morphologies and revealed one-dimensional needle-like crystals. Overall, it was found that these glass formulations remained amorphous with up to 5 mol% Y2O3 addition with further increases in Y2O3 content resulting in significant crystallization