Unveiling the mechanisms of the spin Hall effect in Ta

Spin-to-charge current interconversions are widely exploited for the generation and detection of pure spin currents and are key ingredients for future spintronic devices including spin-orbit torques and spin-orbit logic circuits. In case of the spin Hall effect, different mechanisms contribute to the phenomenon and determining the leading contribution is peremptory for achieving the largest conversion efficiencies. Here, we experimentally demonstrate the dominance of the intrinsic mechanism of the spin Hall effect in highly-resistive Ta. We obtain an intrinsic spin Hall conductivity for $\beta$-Ta of -820$\pm$120 ($\hbar$/e) $\Omega^{-1}cm^{-1}$ from spin absorption experiments in a large set of lateral spin valve devices. The predominance of the intrinsic mechanism in Ta allows us to linearly enhance the spin Hall angle by tuning the resistivity of Ta, reaching up to -35$\pm$3%, the largest reported value for a pure metal.Comment: 9 pages and 4 figures + Supplemental Material (2 pages, 3 figures

Influence of Anodic Conditions on Self-ordered Growth of Highly Aligned Titanium Oxide Nanopores

Self-aligned nanoporous TiO2templates synthesized via dc current electrochemical anodization have been carefully analyzed. The influence of environmental temperature during the anodization, ranging from 2 °C to ambient, on the structure and morphology of the nanoporous oxide formation has been investigated, as well as that of the HF electrolyte chemical composition, its concentration and their mixtures with other acids employed for the anodization. Arrays of self-assembled titania nanopores with inner pores diameter ranging between 50 and 100 nm, wall thickness around 20–60 nm and 300 nm in length, are grown in amorphous phase, vertical to the Ti substrate, parallel aligned to each other and uniformly disordering distributed over all the sample surface. Additional remarks about the photoluminiscence properties of the titania nanoporous templates and the magnetic behavior of the Ni filled nanoporous semiconductor Ti oxide template are also included

Differential diagnosis of illness in travelers arriving from sierra Leone, Liberia, or guinea: A cross-sectional study from the Geosentinel surveillance network

Background: The largest-ever outbreak of Ebola virus disease (EVD), ongoing in West Africa since late 2013, has led to export of cases to Europe and North America. Clinicians encountering ill travelers arriving from countries with widespread Ebola virus transmission must be aware of alternate diagnoses associated with fever and other nonspecific symptoms. Objective: To define the spectrum of illness observed in persons returning from areas of West Africa where EVD transmission has been widespread. Design: Descriptive, using GeoSentinel records. Setting: 57 travel or tropical medicine clinics in 25 countries. Patients: 805 ill returned travelers and new mmigrants from Sierra Leone, Liberia, or Guinea seen between September 2009 and August 2014. Measurements: Frequencies of demographic and travelrelated characteristics and illnesses reported. Results: The most common specific diagnosis among 770 nonimmigrant travelers was malaria (n = 310 [40.3%]), with Plasmodium falciparum or severe malaria in 267 (86%) and non–P. falciparum malaria in 43 (14%). Acute diarrhea was the second most common diagnosis among nonimmigrant travelers (n= 95 [12.3%]). Such common diagnoses as upper respiratory tract infection, urinary tract infection, and influenza-like illness occurred in only 26, 9, and 7 returning travelers, respectively. Few instances of typhoid fever (n = 8), acute HIV infection (n = 5), and dengue (n = 2) were encountered. Limitation: Surveillance data collected by specialist clinics may not be representative of all ill returned travelers. Conclusion: Although EVD may currently drive clinical evaluation of ill travelers arriving from Sierra Leone, Liberia, and Guinea, clinicians must be aware of other more common, potentially fatal diseases. Malaria remains a common diagnosis among travelers seen at GeoSentinel sites. Prompt exclusion of malaria and other life-threatening conditions is critical to limiting morbidity and mortality

Differential limit on the extremely-high-energy cosmic neutrino flux in the presence of astrophysical background from nine years of IceCube data

We report a quasi-differential upper limit on the extremely-high-energy (EHE) neutrino flux above $5\times 10^{6}$ GeV based on an analysis of nine years of IceCube data. The astrophysical neutrino flux measured by IceCube extends to PeV energies, and it is a background flux when searching for an independent signal flux at higher energies, such as the cosmogenic neutrino signal. We have developed a new method to place robust limits on the EHE neutrino flux in the presence of an astrophysical background, whose spectrum has yet to be understood with high precision at PeV energies. A distinct event with a deposited energy above $10^{6}$ GeV was found in the new two-year sample, in addition to the one event previously found in the seven-year EHE neutrino search. These two events represent a neutrino flux that is incompatible with predictions for a cosmogenic neutrino flux and are considered to be an astrophysical background in the current study. The obtained limit is the most stringent to date in the energy range between $5 \times 10^{6}$ and $5 \times 10^{10}$ GeV. This result constrains neutrino models predicting a three-flavor neutrino flux of $E_\nu^2\phi_{\nu_e+\nu_\mu+\nu_\tau}\simeq2\times 10^{-8}\ {\rm GeV}/{\rm cm}^2\ \sec\ {\rm sr}$at$10^9\ {\rm GeV}$. A significant part of the parameter-space for EHE neutrino production scenarios assuming a proton-dominated composition of ultra-high-energy cosmic rays is excluded.Comment: The version accepted for publication in Physical Review

Can scenario-planning support community-based natural resource management? Experiences from three countries in latin america

Community Based Natural Resource Management (CBNRM) is a concept critical to managing socio-ecological systems, but whose implementation needs strengthening. Scenario-planning is one approach that may offer benefits relevant to CBNRM, but whose potential is not yet well understood. We therefore designed, trialled and evaluated a scenario-planning method intended to support CBNRM at three cases, located in Colombia, Mexico and Argentina. Implementing scenario-planning was judged as worthwhile in all three cases, although aspects of it could be challenging to facilitate. The benefits generated were relevant to strengthening CBNRM: encouraging the participation of local people and using their knowledge; enhanced consideration and adaption of future change; and supporting the development of systems thinking. Tracing exactly when and how these benefits arise is challenging, but two elements of the method seemed particularly useful. Firstly, using a systematic approach to discuss how drivers of change may affect local socio-ecological systems helped to foster systems thinking and identify connections between issues. Secondly, explicitly focusing on how to use and respond to scenarios helped identify specific practical activities ('response options') that would support CBNRM despite the pressures of future change. Discussions about response options also highlighted the need for support by other actors (e.g. policy groups): this raises the question of when and how other actors and other sources of knowledge should be involved in scenario-planning, so as to encourage their buy-in to actions identified by the process. We suggest other CBNRM initiatives may benefit from adapting and applying scenario-planning. However, these initiatives should be carefully monitored since further research is required to understand how and when scenario-planning methods may produce benefits, and their strengths and weaknesses versus other methods

A 60-million-year Cenozoic history of western Amazonian ecosystems in Contamana, eastern Peru

Weprovide a synopsis of ~60million years of life history in Neotropical lowlands, based on a comprehensive survey of the Cenozoic deposits along the Quebrada Cachiyacu near Contamana in PeruvianAmazonia. The 34 fossilbearing localities identified have yielded a diversity of fossil remains, including vertebrates,mollusks, arthropods, plant fossils, and microorganisms, ranging from the early Paleocene to the lateMiocene–?Pliocene (N20 successive levels). This Cenozoic series includes the base of the Huchpayacu Formation (Fm.; early Paleocene; lacustrine/ fluvial environments; charophyte-dominated assemblage), the Pozo Fm. (middle + ?late Eocene; marine then freshwater environments; most diversified biomes), and complete sections for the Chambira Fm. (late Oligocene–late early Miocene; freshwater environments; vertebrate-dominated faunas), the Pebas Fm. (late early to early late Miocene; freshwater environments with an increasing marine influence; excellent fossil record), and Ipururo Fm. (late Miocene–?Pliocene; fully fluvial environments; virtually no fossils preserved). At least 485 fossil species are recognized in the Contamana area (~250 ‘plants’, ~212 animals, and 23 foraminifera). Based on taxonomic lists from each stratigraphic interval, high-level taxonomic diversity remained fairly constant throughout themiddle Eocene–Miocene interval (8-12 classes), ordinal diversity fluctuated to a greater degree, and family/species diversity generally declined, with a drastic drop in the early Miocene. The Paleocene–?Pliocene fossil assemblages from Contamana attest at least to four biogeographic histories inherited from (i) Mesozoic Gondwanan times, (ii) the Panamerican realm prior to (iii) the time of South America’s Cenozoic “splendid isolation”, and (iv) Neotropical ecosystems in the Americas. No direct evidence of any North American terrestrial immigrant has yet been recognized in the Miocene record at Contamana.Facultad de Ciencias Naturales y Muse

“El Sexo no es Malo”: Maternal Values Accompanying Contraceptive Use Advice to Young Latina Adolescent Daughters

In this study, we utilized observational methods to identify maternal values and concerns accompanying contraceptive use advice in Latina mother–daughter sexuality conversations. The sample included non-sexually active early adolescents around 12 years of age and their mostly Spanish-speaking Latina mothers. Videotaped conversations were coded for the prevalence of messages related to four sexual values (abstinence, delay sex until older, sex is “normal”, sex is “improper”) and concerns about pregnancy and STD transmission. We examined whether the duration of time spent conversing about these messages was associated with participant characteristics, general communication openness, and the amount of time the dyads spent discussing contraceptive use. Results indicated that Latina mothers who had fewer years of education and lower family income talked longer to their daughters about the need to delay sex, avoid risky situations that would increase their chances of getting pregnant or acquiring an STD, and engage in self-protective practices. Less perceived openness in general communication as reported by both the mothers and the daughters was associated with increased time discussing that sex is improper. Although the duration of contraceptive use messages was brief, mothers and daughters who discussed the fact that sex is normal, and who communicated more about the importance of delaying sex, talked longer about contraceptive use practices compared to mothers and daughters who engaged in minimal discussion of these sexual values