Direct determination of the band offset in atomic layer deposited ZnO hydrogenated amorphous silicon heterojunctions from X ray photoelectroscopy valence band spectra

The chemical composition and band alignment at the heterointerface between ALD grown zinc oxide ZnO and hydrogenated amorphous silicon a Si H is investigated using monochromatized X ray photoelectron spectroscopy. A new approach for obtaining the valence band offset DeltaEV is developed, which consists in fitting the valence band VB spectrum obtained for a Si H with a thin ZnO overlayer as the sum of experimentally obtained VB spectra of a bulk a Si H film and a thick ZnO film. This approach allows obtaining DeltaEV 2.71 0.15 eV with a minimum of assumptions, and also yields information on the change in band bending of both substrate and ZnO film. The band offset results are compared to values obtained using the usual approach of comparing valence band edge to core level energy differences, DeltaEB,CL DeltaEB,VB. Furthermore, a theoretical value for the VB offset is calculated from the concept of charge neutrality level line up, using literature data for the CNLs and the experimentally determined ZnO a Si H interface dipole. The thus obtained value of DeltaEVCNL 2.65 0.3 eV agrees well with the experimental DeltaE

Oxygen and carbon isotope and Sr/Ca signatures of high-latitude Permian to Jurassic calcite fossils from New Zealand and New Caledonia

Article available online 12 November 2015This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.Calcite fossils from New Zealand and New Caledonia provide insight into the Permian to Jurassic climatic history of Southern High Latitudes (southern HL) and Triassic Southern Intermediate Latitudes (southern IL). These results permit comparison with widely studied, coeval sections in Low Latitudes (LL) and IL. Oxygen isotope ratios of well-preserved shell materials indicate a partially pronounced Sea Surface Temperature (SST) gradient in the Permian, whereas for the Triassic no indication of cold climates in the southern HL is found. The Late Jurassic of New Zealand is characterized by a slight warming in the Oxfordian–Kimmeridgian and a subsequent cooling trend in the Tithonian. Systematic variations in the δ13C values of southern HL samples are in concert with those from LL sections and confirm the global nature of the carbon isotope signature and changes in the long-term carbon cycle reported earlier. Systematic changes of Sr/Ca ratios in Late Triassic brachiopods, falling from 1.19 mmol/mol in the Oretian (early Norian) to 0.67 mmol/mol in the Warepan (late Norian) and subsequently increasing to 1.10 mmol/mol in the Otapirian (~ Rhaetian), are observed. Also Sr/Ca ratios of Late Jurassic belemnite genera Belemnopsis and Hibolithes show synchronous changes in composition that may be attributed to secular variations in the seawater Sr/Ca ratio. For the two belemnite genera an increase from 1.17 mmol/mol in the Middle Heterian (~ Oxfordian) to 1.78 mmol/mol in the Mangaoran (~ late Middle Tithonian) and a subsequent decrease to 1.51 mmol/mol in the Waikatoan (~ Late Tithonian) is documented.This project was funded by the Danish Council for Independent Research– Natural Sciences (project 09-072715), the Carlsberg Foundation (project nr 2011-01-0737) provided for CK, and by the University of Copenhagen (IGN). CVU acknowledges funding from the German National Academy of Sciences – Leopoldina (grant nr LPDS 2014-08

Element/Ca, C and O isotope ratios in modern brachiopods: Species-specific signals of biomineralization

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.Fossil brachiopods are of major importance for the reconstruction of palaeoenvironmental conditions, particularly of the Paleozoic. In order to better understand signals of ancient shell materials, modern analogue studies have to be conducted. Here we present C and O isotope data in conjunction with Mg/Ca, Sr/Ca, Mn/Ca and Fe/Ca data for nine modern rhynchonellid and terebratulid brachiopod species from tropical to intermediate latitudes and shallow to very deep marine settings. C and O isotope signals of most species suggest formation of secondary shell layers near or in isotopic equilibrium with ambient seawater. Some species – especially in the suborder Terebratellidina – show partly distinct disequilibrium signals, suggesting some degree of phylogenetic control on the expression of vital effects. Mn/Ca and Fe/Ca ratios measured in the modern species form a baseline to assess fossil preservation, but also yield environmental information. Mg/Ca and Sr/Ca ratios follow previously observed patterns, with all studied brachiopod species comprising low-Mg calcite. Strong covariation of Sr/Ca ratios with Mg/Ca ratios is only observed in rhynchonellids and possibly one terebratulid species, potentially linking the incorporation behaviour of alkaline earth metals to phylogeny. Sr/Ca show a strong negative correlation with δ13C values in terebratellidinid species which exhibit major isotopic disequilibrium and also combined data from three localities for which two species were studied indicate such a negative relation. The observed covariation of Sr/Ca ratios with δ13C values may therefore become a useful tool to detect δ13C disequilibrium and to robustly estimate δ13C values of ambient DIC in deep time.The authors acknowledge comments from two anonymous reviewers and Alberto Pérez-Huerta as well as the editor Michael E. Boettcher which helped to improve the quality and clarity of the manuscript. The authors thank the Museum für Naturkunde Berlin for providing brachiopod specimens of the species F. sanguinolenta (ZMB Bra 1934), M. venosa (ZMB Bra 2028), N. nigricans (ZMB Bra 2441), S. crosnieri (ZMB Bra 2442), C. inconspicua (ZMB Bra 2443), C. racovitzae (ZMB Bra 2444) and L. neozelanica (ZMB Bra 2445) and Andy Gale for providing specimens of T. transversa and Terebratulina sp. The authors are indebted to the crews of RV SONNE during the cruises SO 168 ZEALANDIA and SO 233 WALVIS 2 and their respective shipboard scientific parties. Financial support by the German Ministry of Education and Research (BMBF) within the project SO 168 ZEALANDIA (FKZ: 03G0168) and SO 233 WALVIS 2 (FKZ: 03G0233A) to CL is gratefully acknowledged. CVU acknowledges funding from the Leopoldina – German National Academy of Sciences (grant no. LPDS 2014-08)

Reconstructing Holocene geomagnetic field variation: new methods, models and implications

Reconstructions of the Holocene geomagnetic field and how it varies on millennial timescales are important for understanding processes in the core but may also be used to study long-term solar-terrestrial relationships and as relative dating tools for geological and archaeological archives. Here, we present a new family of spherical harmonic geomagnetic field models spanning the past 9000 yr based on magnetic field directions and intensity stored in archaeological artefacts, igneous rocks and sediment records. A new modelling strategy introduces alternative data treatments with a focus on extracting more information from sedimentary data. To reduce the influence of a few individual records all sedimentary data are resampled in 50-yr bins, which also means that more weight is given to archaeomagnetic data during the inversion. The sedimentary declination data are treated as relative values and adjusted iteratively based on prior information. Finally, an alternative way of treating the sediment data chronologies has enabled us to both assess the likely range of age uncertainties, often up to and possibly exceeding 500 yr and adjust the timescale of each record based on comparisons with predictions from a preliminary model. As a result of the data adjustments, power has been shifted from quadrupole and octupole to higher degrees compared with previous Holocene geomagnetic field models. We find evidence for dominantly westward drift of northern high latitude high intensity flux patches at the core mantle boundary for the last 4000 yr. The new models also show intermittent occurrence of reversed flux at the edge of or inside the inner core tangent cylinder, possibly originating from the equator

Analysing the effects of travel information on public transport traveller’s decision making and learning

This thesis examines the effect of travel information on a public transport traveller’s decision making over time. It investigates whether the effect of information is sustained over time and is affected by its type and reliability. It is postulated that the traveller will attain better decision outcomes over time, and this process is reinforced when given information. It is postulated that dynamic information would produce the best outcomes, followed by static information and no information. A series of computer-based experiments, in which the participants made hypothetical trips by public bus under various travel information and operating conditions, were conducted. At the aggregate level, the hypothesised relationships are not observed at a statistically significant level. At the disaggregate level, day-to-day decisions are shown to relate significantly to the outcome of the previous day, with the participant more likely to seek a more rewarding but riskier choice if the previous day sees no adverse outcome, and vice-versa. When the information is static, decision changes are few and incremental. When it is dynamic, these changes are more frequent and pronounced, with choices ‘anchored’ around values provided by the information. Nonetheless, a significant proportion of participants made no or few changes, regardless of information or operating conditions. The findings suggest a higher propensity for some travellers to use dynamic information over static information over time, regardless of reliability. On the other hand, those who acquire information do not necessarily maximise their utility, implying that they do so for other less quantifiable factors. The benefits of information provision could also be further circumscribed by the heterogeneity of responses. This set of findings suggests that assuming travellers respond to information in a utility-maximising and homogeneous manner may over-estimate the effect of information

Estimation of the threat of IEMI to complex electronic systems

The threat of ultra wideband (UWB) sources is interesting for military issues. This paper summarizes information concerning the voltages generated from some commercially available UWB generator systems and their produced electromagnetic fields. The paper focuses on the coupling of UWB fields into electronic equipment and discusses possible modeling and measurement techniques to estimate such a threat for modern ships. An evaluation procedure for the determination of the induced voltage at the input of an electronic component is presented. This method is based on the computation of the internal electric field and the measurements on a test network, which is similar to the structure of the steering control cabling. It allows the estimation of the potential threat for the ship's electronic equipment due to the exposal to UWB emitting sources

The Dutch EPS Registry:increasing the knowledge of encapsulating peritoneal sclerosis

Encapsulating peritoneal sclerosis (EPS) is a rare condition characterised by fibrotic thickening of the visceral peritoneum, leading to encapsulating of the intestines with partial or total intestinal obstruction. EPS is a serious complication of peritoneal dialysis (PD) with high morbidity and a mortality exceeding 50%. At present, there is uncertainty concerning the incidence and the risk factors involved in the development of EPS. To address these questions a nationwide registry has been initiated. The primary goals of the registry are to record the incidence of EPS and investigate the association of different variables, such as PD duration, medication, dialysis solutions and kidney transplantation with EPS. The registry will improve the knowledge of EPS and will serve to develop guidelines and necessary management strategies. From the registry different research activities can be initiated. A major challenge lies in the establishment of criteria that allow a timely diagnosis of EPS. At present, there are no diagnostic tools that can accurately detect EPS at an early stage. For this reason, besides patients with proven EPS, the clinical suspicion of EPS will be a sufficient criterion for inclusion in the registry. This nationwide EPS registry is currently enrolling patients

RNA secondary structure design

We consider the inverse-folding problem for RNA secondary structures: for a given (pseudo-knot-free) secondary structure find a sequence that has that structure as its ground state. If such a sequence exists, the structure is called designable. We implemented a branch-and-bound algorithm that is able to do an exhaustive search within the sequence space, i.e., gives an exact answer whether such a sequence exists. The bound required by the branch-and-bound algorithm are calculated by a dynamic programming algorithm. We consider different alphabet sizes and an ensemble of random structures, which we want to design. We find that for two letters almost none of these structures are designable. The designability improves for the three-letter case, but still a significant fraction of structures is undesignable. This changes when we look at the natural four-letter case with two pairs of complementary bases: undesignable structures are the exception, although they still exist. Finally, we also study the relation between designability and the algorithmic complexity of the branch-and-bound algorithm. Within the ensemble of structures, a high average degree of undesignability is correlated to a long time to prove that a given structure is (un-)designable. In the four-letter case, where the designability is high everywhere, the algorithmic complexity is highest in the region of naturally occurring RNA.Comment: 11 pages, 10 figure