TEM investigation of YBa2Cu3O7 thin films on SrTiO3 bicrystals

YBa2Cu3O7 films in c-axis orientation on bicrystalline SrTiO3 substrates are investigated by TEM. The films and the substrates are examined in cross-section and in plane view. The grain boundary of the bicrystal substrate contains (110) faceted voids, but is otherwise straight on a nanometer scale. Contrary to this, the film grain boundary is not straight grain boundary can be up to 100 nm for a 100 nm thick film. The deviation from the intended position of the YBCO grain boundary can already occur at the film/substrate interface where it can be as much as ±50 nm

Microstructures of ramp-edge YBa2Cu3Ox/PrBa2Cu3Ox/YBa2Cu3Ox Josephson junctions on different substrates

Ramp-edge YBa2Cu3/PrBa2Cu3Ox/YBa2Cu3Ox Josephson junctions with PrBa2Cu3Ox (PrBCO) or SrTiO3 as a separating layer on different kinds of substrate have been studied by high-resolution electron microscopy. The bottom YBa2Cu3Ox (YBCO) layer and the separating layer (PrBCO or SrTiO3) were epitaxially c oriented, irrespective of the substrate (yttria stabilized zirconia (YSZ), SrTiO3 or NdGaO3, all in (001) orientation). The use of ion milling in the manufacturing of Josephson junctions was found to yield smooth slopes with an angle of about 20°. The Josephson junction was facing away from the beam direction was found to have a dimple in the substrate near the base of the junction. The barrier layers were observed to have a homogeneous thickness. These layers were as the top YBCO layers were oriented with their c-axis perpendicular to (001) plane of the substrate for perovskite substrates and perpendicular to the surface for YSZ substrates. In the case of a YSZ substrate, the dimple in the substrate as well as the slope of the substrate close to the base of the junction were found to lead to small angle grain boundaries in the YBCO film as well as randomly oriented YBCO grains, which results in a poor ramp-edge junction. In the case of SrTiO3 or NdGaO3 substrate, all components of the device were fully epitaxial, thus resulting in good ramp-edge junctions

A HREM study of the atomic structure and the growth mechanism of the YBa2Cu3O7/YSZ interface

The interface between yttria-stabilized zirconia (YSZ) substrate and YBa2Cu3O7 (YBCO) film was studied by high-resolution electron microscopy. In all specimens we have observed an intermediate layer of BaZrO3 located between the substrate YSZ and YBCO. The BaZrO3 layer is composed of almost equally aligned domains being 4¿8 nm in the lateral directions. Reaction products such as Y and Cu oxides were never observed in or close to the BaZrO3 reaction layer but they do occur in the YBCO film. The stacking sequence of BaZrO3/YBCO is predominantly (BaZrO3)-ZrO2-BaO/CuO-BaO-(YBCO) with CuO layer as the beginning YBCO layer. Sometimes a stacking sequence (BaZrO3)-ZrO2-BaO/BaO-CuO2-(YBCO) with a BaO layer as the beginning YBCO layer was observed. This stacking is related to a dislocation with Burgers vector a'/2 [111], where a' = 0.42 nm is the lattice constant of the cubic BaZrO3. Three main epitaxial relations (0°, 45°, 9°) between YSZ and YBCO were observed. These can be explained by near-coincidence site lattices ¿ = 25, ¿ = 49 and ¿ = 13 (for a YSZ substrate). Usually the (001) plane of the YBCO film is parallel to the (001) plane of the BaZrO3 layer and parallel to the substrate surface. In case YBCO is grown on an inclined YSZ substrate, the (001) plane of the YBCO film is parallel to the substrate surface and thus not parallel to the (001) plane of the YSZ substrate

Learning to love the world's most hated crop

The 2019 Inter-governmental Panel (IPCC) Report on Climate Change and Land highlighted the urgency and scale of the environmental impact from human-induced landscape change. Palm oil has historically had a particularly negative reputation for driving deforestation, biodiversity loss, greenhouse gas emissions, social exploitation and damaging health. In the eyes of many in the West, it is regarded as the world’s most hated crop. However, palm is highly productive compared with other crops and produces 40% of the worlds edible oil from only 5% of vegetable oil producing land and 0.4% of agricultural land in total. It has the potential to meet future demand for oil with minimum additional environmental and climate impact compared with other sources of vegetable oil. The related high value density has the potential to move millions of vulnerable smallholder farmers out of poverty. Given the conclusions of the IPCC Climate and Land Report, it is therefore important to re-examine the crop’s reputation in light of the accumulated evidence and to properly understand the full impacts across the environmental, health, social and economic factors. We present a comprehensive review of the benefits and risks of the crop across these dimensions and provide a new synthesis. We conclude that while oil palm has had a significant negative impact on habitat and biodiversity, it plays a minor role compared with poaching, illegal logging and threats from climate change. There are important opportunities for the industry to reverse this damage. Its reputation for negative health impacts are not backed up by the scientific evidence and indeed there may be health benefits from substituting some oils in the diet with oil palm. Positive social and economic impacts are most obvious in areas where proper market-led economies are in place, but there can be significant negative social impacts in less developed areas. We conclude that much of the reputation of palm oil is not based on a balanced interpretation of the scientific evidence. Provided future development is zero deforestation, does not occur on peat, uses methane capture technology at the mills, empowers indigenous smallholders and supports the regeneration of secondary forest, we conclude that oil palm can be the most environmentally, socially and economically sustainable means to meet future demand for vegetable oil. Indeed, with pro-active collaboration with relevant non-government organisations, oil palm can be part of the solution to reversing the degradation of tropical forest biome

The atomic structure of large-angle grain boundaries Σ5\Sigma 5 and Σ13\Sigma 13 in YBa2Cu3O7−δ{\rm YBa_2Cu_3O_{7-\delta}} and their transport properties

We present the results of a computer simulation of the atomic structures of large-angle symmetrical tilt grain boundaries (GBs) $\Sigma 5$ (misorientation angles \q{36.87}{^{\circ}} and \q{53.13}{^{\circ}}), $\Sigma 13$ (misorientation angles \q{22.62}{^{\circ}} and \q{67.38}{^{\circ}}). The critical strain level $\epsilon_{crit}$ criterion (phenomenological criterion) of Chisholm and Pennycook is applied to the computer simulation data to estimate the thickness of the nonsuperconducting layer ${\rm h_n}$ enveloping the grain boundaries. The ${\rm h_n}$ is estimated also by a bond-valence-sum analysis. We propose that the phenomenological criterion is caused by the change of the bond lengths and valence of atoms in the GB structure on the atomic level. The macro- and micro- approaches become consistent if the $\epsilon_{crit}$ is greater than in earlier papers. It is predicted that the symmetrical tilt GB $\Sigma5$ \theta = \q{53.13}{^{\circ}} should demonstrate a largest critical current across the boundary.Comment: 10 pages, 2 figure

Measurement properties of the Minimal Insomnia Symptom Scale (MISS) in an elderly population in Sweden

<p>Abstract</p> <p>Background</p> <p>Insomnia is common among elderly people and associated with poor health. The Minimal Insomnia Symptom Scale (MISS) is a three item screening instrument that has been found to be psychometrically sound and capable of identifying insomnia in the general population (20-64 years). However, its measurement properties have not been studied in an elderly population. Our aim was to test the measurement properties of the MISS among people aged 65 + in Sweden, by replicating the original study in an elderly sample.</p> <p>Methods</p> <p>Data from a cross-sectional survey of 548 elderly individuals were analysed in terms of assumptions of summation of items, floor/ceiling effects, reliability and optimal cut-off score by means of ROC-curve analysis and compared with self-reported insomnia criteria.</p> <p>Results</p> <p>Corrected item-total correlations ranged between 0.64-0.70, floor/ceiling effects were 6.6/0.6% and reliability was 0.81. ROC analysis identified the optimal cut-off score as ≥7 (sensitivity, 0.93; specificity, 0.84; positive/negative predictive values, 0.256/0.995). Using this cut-off score, the prevalence of insomnia in the study sample was 21.7% and most frequent among women and the oldest old.</p> <p>Conclusions</p> <p>Data support the measurement properties of the MISS as a possible insomnia screening instrument for elderly persons. This study make evident that the MISS is useful for identifying elderly people with insomnia-like sleep problems. Further studies are needed to assess its usefulness in identifying clinically defined insomnia.</p

Sequence Variation in Malayan Tapir (Tapirus indicus) Inferred Using Partial Sequences of the Cytochrome b Segment of the Mitochondrial DNA

Comparison of 321 bp long mtDNA cytochrome b sequences of wild and captive Malayan tapir (Tapirus indicus)revealed low variation among the individuals investigated. Phylogenetic analyses using distance (neighbor-joining) analysis supported the monophyletic status of the Malayan tapir. Two haplotypes were identified out of 13 Malayan tapir analyzed

Importance of Small Forest Fragments in Agricultural Landscapes for Maintaining Orangutan Metapopulations

Historically, orangutans (Pongo spp.) lived in large contiguous areas of intact rainforest. Today, they are also found in highly modified and fragmented landscapes dominated by oil palm or industrial timber plantations; a situation that calls for new conservation approaches. Here we report signs of orangutan presence in more than 120 small forest fragments of less than 500 ha in size and isolated in extensive oil palm plantations across Borneo. We confirmed the long-term presence of adult resident females with dependent young in 42% of the fragments assessed by ground survey (n=50), and the regular sightings of males traveling across the landscape. We argue that orangutans using and living in small isolated forest patches play an essential part in the metapopulation by maintaining gene flow among larger sub-populations distributed across multiple-use landscapes. In some cases, translocations may be necessary when the animals are in imminent danger of being killed and have no other refuge. However, the impacts of removing animals from spatially dispersed metapopulations could inadvertently decrease critical metapopulation functionality necessary for long-term viability. It is clear that orangutans need natural forest to survive. However, our findings show that forest fragments within agricultural landscapes can also complement conservation areas if they are well distributed, properly connected and managed, and if orangutan killing is prevented. Efforts to better understand the dynamics and the functionality of an orangutan metapopulation in forest-farmland landscape mosaics characteristic of the Anthropocene are urgently needed to design more efficient conservation strategies for the species across its range

Denial of long-term issues with agriculture on tropical peatlands will have devastating consequences

Non peer reviewe