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Since low-income and social housing are among the most vulnerable built environments to climate change, this article evaluates the energy performance of social housing in the context of enabling net-zero carbon social housing in South Africa (SA). It seeks to investigate how improved and conscious energy-efficient design in the context of social housing contributes toward a climate change mitigation response in SA. The article analyses energy use and indoor comfort, based on ASHRAE 55-2004 Standard, of two social housing case studies to review the potential of the social housing sector to contribute to the national climate mitigating agenda. The findings highlight that the housing provision itself is not an adequate response, but that bio-climatic design solutions with appropriate spatial and material choices, along with efficient envelope articulation, play a critical role in lowering energy use and improving user comfort. There is, however, a need to challenge the growing advent of (energy-) inefficient and carbon-intensive social housing in SA and simultaneously address the parallel crisis of homelessness, to enable a sustainable future for the built environment.

Zero-Acreage Farming (ZAF) recently developed as a novel land-use form and is aimed at addressing food security and sustainable urban development. While it is often lauded as a sustainable land-use form with potential to improve resource consumption and urban sustainability, little research into the spatial and technological requirements of this land-use form is available. This study undertakes a comparative analysis of ZAF and ground-based urban agriculture (UA) farms in diverse countries to differentiate their technical and spatial implementation parameters and uncover ZAF-specific characteristics and their implementation feasibility in rapidly developing cities. This qualitative study uses semi-structured interviews, triangulated with observational studies, to document ZAF and UA farms in South Africa, Belgium, the Netherlands and Singapore. The findings reveal UA as highly flexible, modular landuse forms while, contrastingly, the technological focus of ZAF farms often results in monofunctional and inflexible once implemented, isolated, and non-contextual solutions. While ZAF farms are appropriate to improve livelihoods and food security in dense urban contexts, the study highlights trends that must be addressed to promote the implementation of ZAF in poorer rapidly developing cities.

Real-world data on the use of interleukin-17 (IL-17) inhibitors for the treatment of psoriasis are limited.To evaluate and compare the efficacy, safety, and drug survival of IL-17 inhibitors.This retrospective study analyzed the BIOREP registry data of patients treated with at least one IL-17 inhibitor (secukinumab, ixekizumab, and brodalumab).In total, 949 patients were included. The improvement in PASI score was significant for all drugs, and the proportion of patients achieving PASI 75, 90, and 100 after both 3 and 24 months of therapy was highest for brodalumab, followed by ixekizumab and secukinumab. The Dermatology Life Quality Index score decreased to ˂3 after 3 months and to ˂2 after 24 months of therapy for all inhibitors. Loss of effectiveness was the major reason for discontinuation in 17.2% of patients, followed by adverse events in 3.2% of patients. The drug survival probability was the highest for brodalumab, followed by ixekizumab and secukinumab. Negative predictors for treatment discontinuation were obesity and the number of treatment lines, whereas a positive predictor was the presence of concomitant psoriatic arthritis; sex had no influence.This real-life study demonstrated the effectiveness and good safety profile of all currently available IL-17 inhibitors.

Current knowledge about human papillomavirus (HPV) infection in psoriasis patients treated with biologics is limited. In this study we evaluated the prevalence of oral and genital HPV infection in psoriasis patients treated with biologics or topical therapy for at least 6 months. The presence of HPV DNA in oral rinse and genital smears was evaluated. In total, 267 patients who met the inclusion criteria and agreed to participate were enrolled: 110 (41.2%) on topical therapy, 84 (31.5%) on anti-TNF-alpha therapy, 31 (11.6%) on anti-IL-12/23 therapy and 42 (15.7%) on anti-IL-17 therapy. The presence of genital HPV infection was detected in 34.6% of men receiving anti-TNF-α treatment, in 25.0% of patients on anti-IL-12/23 and 18.8% of patients on anti-IL-17 therapy. The difference in prevalence was not statistically different from men on topical treatment (26.3%). Prevalence of oral HPV infection was higher across all of the biologic groups (11.9% for anti-TNF-α, 12.9% for anti-IL-12/23 and 19.0% for anti-IL-17) compared to patients on topical therapy (7.3%), but statistically significant only for anti-IL-17 (p 0.05). The presence of oral HPV infection in patients treated with biologics was significantly higher (44.0%) in patients on long-term biologic treatment (8 years) compared to patients taking biologics for a shorter period (9.1%; p 0.01). Our results suggest that patients on biologics for psoriasis have a higher prevalence of oral HPV infection compared to patients on topical treatment. Long-term treatment with biologics seems to be associated with a higher prevalence of oral HPV infection, independent of previous conventional immunosuppressive therapy.

Background Drug survival, defined as the length of time from initiation to discontinuation of a given therapy, allows comparisons between drugs, helps to predict patient's likelihood of remaining on a specific treatment, and achieving the best decision for each patient in daily clinical practice. Objective The aim of this study was to provide data on drug survival of secukinumab, ixekizumab, brodalumab, guselkumab, tildrakizumab, and risankizumab in a large international cohort, and to identify clinical predictors that might have an impact on the drug survival of these drugs. Methods This was a retrospective, multicentric, multi-country study that provides data of adult patients with moderate to severe psoriasis who started treatment with an interleukin (IL)-17 or IL-23 inhibitor between 1 February 2015 and 31 October 2021. Data were collected from 19 distinct hospital and non-hospital-based dermatology centers from Canada, Czech Republic, Italy, Greece, Portugal, Spain, and Switzerland. Kaplan-Meier estimator and proportional hazard Cox regression models were used for drug survival analysis. Results A total of 4866 treatment courses (4178 patients)-overall time of exposure of 9500 patient-years-were included in this study, with 3164 corresponding to an IL-17 inhibitor (secukinumab, ixekizumab, brodalumab) and 1702 corresponding to an IL-23 inhibitor (guselkumab, risankizumab, tildrakizumab). IL-23 inhibitors had the highest drug survival rates during the entire study period. After 24 months of treatment, the cumulative probabilities of drug survival were 0.92 (95% confidence interval [CI] 0.89-0.95) for risankizumab, 0.90 (95% CI 0.88-0.92) for guselkumab, 0.80 (95% CI 0.76-0.84) for brodalumab, 0.79 (95% CI 0.76-0.82) for ixekizumab, and 0.75 (95% CI 0.73-0.77) for secukinumab. At 36 months, only guselkumab [0.88 (95% CI 0.85-0.91)], ixekizumab [0.73 (95% CI 0.70-0.76)], and secukinumab [0.67 (95% CI 0.65-0.70)] had more than 40 patients at risk of drug discontinuation. Only two drugs had more than 40 patients at risk of drug discontinuation at 48 months, with ixekizumab demonstrating to have a higher cumulative probability of drug survival [0.71 (95% CI 0.68-0.75)] when compared with secukinumab [0.63 (95% CI 0.60-0.66)]. Secondary failure was the main cause for drug discontinuation. According to the final multivariable model, patients receiving risankizumab, guselkumab, and ixekizumab were significantly less likely to discontinue treatment than those receiving secukinumab. Previous exposure to biologic agents, absent family history of psoriasis, higher baseline body mass index (BMI), and higher baseline Psoriasis Area and Severity Index (PASI) were identified as predictors of drug discontinuation. Conclusion The cumulative probability of drug survival of both IL-17 and IL-23 inhibitors was higher than 75% at 24 months, with risankizumab and guselkumab demonstrating to have overall cumulative probabilities >= 90%. Biological agent chosen, prior exposure to biologic agents, higher baseline BMI and PASI values, and absence of family history of psoriasis were identified as predictors for drug discontinuation. Risankizumab, guselkumab, and ixekizumab were less likely to be discontinued than secukinumab.

Atopic dermatitis is a chronic inflammatory intensively pruritic skin disease. Patients with moderate-to-severe atopic dermatitis or with difficult-to-treat areas are candidates for systemic therapy, especially when topical therapy is inadequate. Currently, we have available not only conventional immunosuppressive systemic therapy, but also targeted biological therapy, which has shown a remarkable reduction in clinical severity with a good safety profile. Dupilumab has been approved to treat moderate-to-severe atopic dermatitis. Even though the therapy has been available for more than 3 years, there are still limited data regarding the treatment of patients with concomitant cancer. Previous immunosuppressive treatment for atopic dermatitis, such as cyclosporine or azathioprine, poses a safety risk for patients with malignant disease. We present a case series of three patients with advanced cancer and severe atopic dermatitis treated with dupilumab for an average of 17 months with a great response toward atopic dermatitis without cancer recurrence. One patient had colorectal cancer’ the second and the third both had cancer duplicity—colorectal and kidney cancer and penile squamous cell carcinoma with prostate cancer. Our cases suggest that dupilumab can safely control atopic dermatitis in patients with advanced cancer.

In this paper we describe a new spin detector designed and manufactured at SPbPU. This device makes it possible to analyze the polarization of the secondary electron flux conserving the information about the electrons' spatial distribution. The main stages of development, construction and testing the detector are discussed in details. As a result, the possibility of implementing such devices has been proved in principle. At the same time, both high spatial resolution of this device and its efficiency were demonstrated. Combining such detectors with hemispherical energy analyzers will make it possible to obtain spin-resolved dispersion images of the structure under study.

Sixteen volunteers each drank 700 ml sugar-containing soft drink during two successive periods and the blood sugar was measured at 10 min intervals together with electrical impedance spectroscopy and near infrared spectroscopy (NIR). A maximum correlation of 0.46 was found for the electrical measurements but no clear separation between low and high blood glucose levels were found in the NIR measurements. The latter was attributed to the experimental design where the NIR probe was removed from the skin between each measurement.

В работе описывается новый спиновый детектор, разработанный, сконструированный и изготовленный в СПбПУ. Такой прибор позволяет анализировать поляризацию потока вторичных электронов, сохраняя информацию об их пространственном распределении. Представлены основные этапы создания и тестирования разработанного устройства, продемонстрированы результаты испытаний его отдельных узлов. В результате доказана принципиальная возможность реализации подобных устройств. При этом продемонстрированы как высокое пространственное разрешение данного прибора, так и его эффективность. Совмещение таких детекторов с полусферическим энергоанализаторами современных электронных спектрометров позволит получать спин-разрешенные дисперсионные зависимости исследуемой структуры., In this paper we describe a new spin detector designed and manufactured at SPbPU. This device makes it possible to analyze the polarization of the secondary electron flux conserving the information about the electrons' spatial distribution. The main stages of development, construction and testing the detector are discussed in details. As a result, the possibility of implementing such devices has been proved in principle. At the same time, both high spatial resolution of this device and its efficiency were demonstrated. Combining such detectors with hemispherical energy analyzers will make it possible to obtain spin-resolved dispersion images of the structure under study.

This paper shows how the detailed dispersion of the giant Rashba split surface states in the ferroelectric \ensuremath{\alpha}--GeTe(111) can be resolved by static ARPES and surface potassium doping. The authors further confirm the Rashba mechanism for these states by moving them into the occupied part of the band structure, in good agreement with state of the art DFT calculations.

The concentration of rebirthal forces on the platform of associations and organizations became a significant phenomenon in the 19th century Bohemian lands. The work will try to show what challenges the efforts of the rebirth associations had to face, and what specifics the organizations of a purely female membership had. An example of such a society was Sestry slovanské, later called Spolek slovanek, which was founded in the stormy year of 1848 and whose activity, which included both publishing and educational activities, is the subject of this work. By the synthesis of archival research and study of professional literature I will attempt to map the internal relations of the society and it's public activities.

In response to the burgeoning building integrated agriculture (BIA) discourse and industry, and assumptions of this land use form as a climate change adaptation strategy, this study considers the impact of rooftop greenhouses (RTGs) on the thermal performance of the built environment in current and future climate conditions. Based on empirical evidence, the study simulates the thermal impact of completely retrofitting an existing building in a Southern African urban context with passively controlled, non-integrated RTGs under current and future climate change affected climatic conditions. The study concludes that the current greenhouse technologies used in South African rooftop farms provide limited thermal modulation capacity for farmers, as well as generally negatively affecting the thermal performance of the associated buildings. Simulating both highly and poorly insulated buildings reveal contrasting impacts on the indoor thermal environment, with a 0.73 °C decrease and 0.55 °C increase in mean temperatures, respectively. Conversely, the highly insulated simulation reveals an annual energy consumption increase of 3.5%, which progressively worsens under higher climate change induced temperatures. These findings, based on current practices in the BIA industry, hope to inform both the choice of technology, as well as the development of appropriate greenhouse technologies to maximise their performance and enable co-benefits as often assumed in the industry.

Problematika kožnich onemocněni v dětskem věku je nesmirně siroka, pravě kožni obtiže představuji jeden z nejcastějsich důvodů navstěvy pediatra. Nejenom lecba, ale už samotna diagnostika skýta řadu uskali a může představovat znacnou výzvu i pro zkuseneho dermatologa. Ve sve praxi se autor a jeho kolegove pravidelněji setkavaji s některými neuspěsně lecenými chorobami, v důsledku opakujicich se chyb v předchozim diagnostickem procesu. Přestože se větsinou nejedna o dramaticke chyby – ktere by ohrozily pacienta na životě – teprve až jejich odhaleni a napraveni vede k vyřeseni situace. Někdy dokonce ani neni nutne nastavovat novou ci měnit zavedenou terapii, staci pouhe podrobnějsi rozebrani důvodu navstěvy a spravna edukace. Na zakladě těchto klinických zkusenosti tak vznikl clanek – s výběrem temat, jež odražeji některe castěji se opakujici situace – jehož ambici je, aby byl co možna nejvice užitecným pomocnikem pro každodenni praxi pediatrů a pomahal předchazet zmiňovaným potencialnim omylům. Kvůli prakticnosti tak casto neni uvaděna obsirna kompletni diferencialni diagnoza a jedna se spise o soubor doporuceni a rad.

Germanium telluride features special spin-electric effects originating from spin-orbit coupling and symmetry breaking by the ferroelectric lattice polarization, which opens up many prospectives for electrically tunable and switchable spin electronic devices. By Mn doping of the α-GeTe host lattice, the system becomes a multiferroic semiconductor possessing magnetoelectric properties in which the electric polarization, magnetization and spin texture are coupled to each other. Employing spin- and angle-resolved photoemission spectroscopy in bulk- and surface-sensitive energy ranges and by varying dipole transition matrix elements, we disentangle the bulk, surface and surface-resonance states of the electronic structure and determine the spin textures for selected parameters. From our results we derive a comprehensive model of the α-GeTe surface electronic structure which fits to experimental data and first principle theoretical predictions and we discuss the unconventional evolution of the Rashba-type spin splitting upon manipulation by external B- and E-fields.

Using soft x-ray angle-resolved photoemission spectroscopy we probed the bulk electronic structure of T_{d}-MoTe_{2}. We found that on-site Coulomb interaction leads to a Lifshitz transition, which is essential for a precise description of the electronic structure. A hybrid Weyl semimetal state with a pair of energy bands touching at both type-I and type-II Weyl nodes is indicated by comparing the experimental data with theoretical calculations. Unveiling the importance of Coulomb interaction opens up a new route to comprehend the unique properties of MoTe_{2}, and is significant for understanding the interplay between correlation effects, strong spin-orbit coupling and superconductivity in this van der Waals material.

The discovery of Weyl semimetals represents a significant advance in topological band theory. They paradigmatically enlarged the classification of topological materials to gapless systems while simultaneously providing experimental evidence for the long-sought Weyl fermions. Beyond fundamental relevance, their high mobility, strong magnetoresistance, and the possible existence of even more exotic effects, such as the chiral anomaly, make Weyl semimetals a promising platform to develop radically new technology. Fully exploiting their potential requires going beyond the mere identification of materials and calls for a detailed characterization of their functional response, which is severely complicated by the coexistence of surface- and bulk-derived topologically protected quasiparticles, i.e., Fermi arcs and Weyl points, respectively. Here, we focus on the type-II Weyl semimetal class in which we find a stoichiometry-dependent phase transition from a trivial to a nontrivial regime. By exploring the two extreme cases of the phase diagram, we demonstrate the existence of a universal response of both surface and bulk states to perturbations. We show that quasiparticle interference patterns originate from scattering events among surface arcs. Analysis reveals that topologically nontrivial contributions are strongly suppressed by spin texture. We also show that scattering at localized impurities can generate defect-induced quasiparticles sitting close to the Weyl point energy. These give rise to strong peaks in the local density of states, which lift the Weyl node, significantly altering the pristine low-energy spectrum. Remarkably, by comparing the WTe2 and the MoTe2 cases we found that scattering response and topological transition are not directly linked. Visualizing the existence of a universal microscopic response to scattering has important consequences for understanding the unusual transport properties of this class of materials. Overall, our observations provide a unifying picture of the type-II Weyl phase diagram.

We report on the electronic structure of the elemental topological semimetal α − Sn on InSb(001). High-resolution angle-resolved photoemission data allow us to observe the topological surface state (TSS) that is degenerate with the bulk band structure and show that the former is unaffected by different surface reconstructions. An unintentional p -type doping of the as-grown films was compensated by deposition of potassium or tellurium after the growth, thereby shifting the Dirac point of the surface state below the Fermi level. We show that, while having the potential to break time-reversal symmetry, iron impurities with a coverage of up to 0.25 monolayers do not have any further impact on the surface state beyond that of K or Te. Furthermore, we have measured the spin-momentum locking of electrons from the TSS by means of spin-resolved photoemission. Our results show that the spin vector lies fully in-plane, but it also has a finite radial component. Finally, we analyze the decay of photoholes introduced in the photoemission process, and by this gain insight into the many-body interactions in the system. Surprisingly, we extract quasiparticle lifetimes comparable to other topological materials where the TSS is located within a bulk band gap. We argue that the main decay of photoholes is caused by intraband scattering, while scattering into bulk states is suppressed due to different orbital symmetries of bulk and surface states.

A combined scanning tunneling microscopy, angle- and spin-resolved photoemission spectroscopy and density functional theory study of graphene on Ir(1 1 1) intercalated with a well-ordered, full Pb monolayer is presented. Lead intercalation between graphene and Ir(111) reduces the coupling to the metallic substrate in such a way that its corrugation becomes negligible and distortions of the linear dispersion largely disappear, while graphene's sublattice symmetry is maintained and it turns out to be n-doped. Remarkably, the spin–orbit splittings induced by the proximity of the Ir(1 1 1) surface are preserved after Pb intercalation in a wide energy range. We further show that the Pb/Ir(1 1 1) surface induces a complex spin texture with both in-plane and out-of-plane components. Our calculations reveal the origin of the out-of-plane spin components in graphene to trace back to the out-of-plane spin-polarized surface and resonance states of Ir(1 1 1), while the Pb interlayer on its own does not induce any vertical spin polarization in the carbon sheet. However, the Brillouin zone folding imposed by the rectangular symmetry of the intercalated Pb layer plays an instrumental role in the spin–orbit coupling (SOC) transfer to graphene, as well as in the linearization of its bands. Finally, since no sizeable gap is observed at the Dirac point, we suggest that an intrinsic (Kane and Mele type) SOC does not exceed the extrinsic (Rashba) SOC for graphene on Pb/Ir(111)., We acknowledge the support by the Basque Departamento de Educacion, UPV/EHU (Grant No. IT-756-13), Spanish Ministerio de Economia y Competitividad (MINECO Grants No. FIS2016- 75862-P, MAT2015-66888-C3-1R and FIS2015-67367-C2-1-P), Comunidad de Madrid (MAD2DCM and Nanofrontmag) and Tomsk State University competitiveness improvement programme (project No. 8.1.01.2017). The support by the Saint Petersburg State University (Grant No. 15.61.202.2015) and Russian Foundation for Basic Research (Grant No. 18-32-00145) are also acknowledged. The part of photoemission measurements had been supported by Russian Science Foundation Grant No. 18-12-00062. IMDEA Nanociencia acknowledges support from the ‘Severo Ochoa’ Programme for Centres of Excellence in R&D (MINECO, Grant SEV-2016-0686).

Monolayer structures of Pb on Si(111) attracted recently considerable interest as superconductivity was found in these truly two-dimensional (2D) structures. In this study, we analyzed the electronic surface band structure of the so-called striped incommensurate Pb phase with $\frac{4}{3}$ ML coverage by means of spin-resolved photoemission spectroscopy. Our results fully agree with density functional theory calculations done by Ren et al. [Phys. Rev. B 94, 075436 (2016)]. We observe a local Zeeman-type splitting of a fully occupied and spin-polarized surface band at the ${\overline{\text{K}}}_{\sqrt{3}}$ points. The growth of this densely packed Pb structure results in the formation of imbalanced rotational domains, which triggered the detection of ${C}_{3v}$ symmetry forbidden spin components for surface states around the Fermi energy. Moreover, the Fermi surface of the metallic surface state of this phase is Rashba spin split and revealed a pronounced warping. However, the 2D nesting vectors are incommensurate with the atomic structure, thus keeping this system rather immune against charge density wave formation and possibly enabling a superconducting behavior.

Spin- and angle-resolved photoemission spectroscopy is used to reveal that a large spin polarization is observable in the bulk centrosymmetric transition metal dichalcogenide MoS2. It is found that the measured spin polarization can be reversed by changing the handedness of incident circularly-polarized light. Calculations based on a three-step model of photoemission show that the valley and layer-locked spin-polarized electronic states can be selectively addressed by circularly-polarized light, therefore providing a novel route to probe these hidden spin-polarized states in inversion-symmetric systems as predicted by Zhang et al. [Nature Physics 10, 387 (2014)]., Comment: 6 pages, 4 figures. Accepted for publication in Physical Review Letters

This article describes strategic design decisions that architects can make during the initial stages of a project to minimise the use of construction materials, reduce carbon emissions and increase energy efficiency. A proposed prototypical Bus Rapid Transit (BRT) station Switch is used as a case study. The investigation focuses on minimising the use of construction materials through an iterative design and assessment process. This article extends an earlier study which analysed existing BRT stations in South Africa by conducting comparative life-cycle analyses (LCA). The earlier study by Hugo, Stoffberg & Barker (2012) identified a series of guidelines to inform the design of low-carbon and embodied energy BRT stations and determined a specific station, the MyCiti station, as the most efficient in terms of its carbon footprint and embodied energy intensity. As a result, the MyCiti station was identified as benchmark for future LCAs of station designs. The Switch prototypical BRT station is purpose designed for the Tshwane1 context and uses the identified guidelines (Hugo, Stoffberg & Barker, 2012) as well as carbon footprint (CF) and embodied energy (EE) of construction systems and materials as design informants generated from a study conducted by Jones (2011b). These informed material choices, use of low-carbon structural systems and integration of multifunctional station components. A cradle-to-gate2 life-cycle assessment compares the CF and EE of the Switch station and an existing South African precedent, the MyCiti station in Cape Town. The Switch station is 35% and 34% (4.08 GJ/m2 & 378.6kgCO2/m2 vs 6.28 GJ/m2 & 574.7kgCO2/m2) more efficient than the existing MyCiti station, in terms of respective embodied energy intensity and carbon-footprint intensity. This prototype is proposed as a benchmark for prospective life-cycle analyses to inform the material choice and design of future BRT stations in South Africa.

Identifikace bulkových a povrchových Rashba stavů v ferroelektrickém GeTe Macroscopic ferroelectric order in α-GeTe with its noncentrosymmetric lattice structure leads to a giant Rashba spin splitting in the bulk bands due to strong spin-orbit interaction. Direct measurements of the bulk band structure using soft x-ray angle-resolved photoemission (ARPES) reveals the three-dimensional electronic structure with spindle torus shape. By combining high-resolution and spin-resolved ARPES as well as photoemission calculations, the bulk electronic structure is disentangled from the two-dimensional surface electronic structure by means of surface capping, which quenches the complex surface electronic structure. This unravels the bulk Rashba-split states in the ferroelectric Rashba α-GeTe(111) semiconductor exhibiting a giant spin splitting with Rashba parameter αR around 4.2 eV A°, the highest of so-far known materials.

The interplay between electronic eigenstates, spin, and orbital degrees of freedom, combined with fundamental breaking of symmetries is currently one of the most exciting fields of research. Multiferroics such as (GeMn)Te fulfill these requirements providing unusual physical properties due to the coexistence and coupling between ferromagnetic and ferroelectric order in one and the same system. Here we show that multiferroic (GeMn)Te inherits from its parent ferroelectric {\alpha}-GeTe compound a giant Rashba splitting of three-dimensional bulk states which competes with the Zeeman spin splitting induced by the magnetic exchange interactions. The collinear alignment of ferroelectric and ferromagnetic polarization leads to an opening of a tunable Zeeman gap of up to 100 meV around the Dirac point of the Rashba bands, coupled with a change in spin texture by entanglement of magnetic and spin-orbit order. Through applications of magnetic fields, we demonstrate manipulation of spin- texture by spin resolved photoemission experiments, which is also expected for electric fields based on the multiferroic coupling. The control of spin helicity of the bands and its locking to ferromagnetic and ferroelectric order opens fascinating new avenues for highly multifunctional multiferroic Rashba devices suited for reprogrammable logic and/or nonvolatile memory applications., Comment: 10 pages, 4 figures

A topological insulator protected by time-reversal symmetry is realized via spin-orbit interaction-driven band inversion. The topological phase in the Bi(1-x)Sb(x) system is due to an odd number of band inversions. A related spin-orbit system, the Pb(1-x)Sn(x)Te, has long been known to contain an even number of inversions based on band theory. Here we experimentally investigate the possibility of a mirror symmetry-protected topological crystalline insulator phase in the Pb(1-x)Sn(x)Te class of materials that has been theoretically predicted to exist in its end compound SnTe. Our experimental results show that at a finite Pb composition above the topological inversion phase transition, the surface exhibits even number of spin-polarized Dirac cone states revealing mirror-protected topological order distinct from that observed in Bi(1-x)Sb(x). Our observation of the spin-polarized Dirac surface states in the inverted Pb(1-x)Sn(x)Te and their absence in the non-inverted compounds related via a topological phase transition provide the experimental groundwork for opening the research on novel topological order in quantum devices.

Helical Dirac fermions—charge carriers that behave as massless relativistic particles with an intrinsic angular momentum (spin) locked to its translational momentum—are proposed to be the key to realizing fundamentally new phenomena in condensed matter physics. Prominent examples include the anomalous quantization of magneto-electric coupling, half-fermion states that are their own antiparticle, and charge fractionalization in a Bose– Einstein condensate, all of which are not possible with conventional Dirac fermions of the graphene variety. Helical Dirac fermions have so far remained elusive owing to the lack of necessary spin-sensitive measurements and because such fermions are forbidden to exist in conventional materials harbouring relativistic electrons, such as graphene or bismuth. It has recently been proposed that helical Dirac fermions may exist at the edges of certain types of topologically ordered insulators—materials with a bulk insulating gap of spin–orbit origin and surface states protected against scattering by time-reversal symmetry—and that their peculiar properties may be accessed provided the insulator is tuned into the so-called topological transport regime. However, helical Dirac fermions have not been observed in existing topological insulators. Here we report the realization and characterization of a tunable topological insulator in a bismuthbased class of material by combining spin-imaging and momentum-resolved spectroscopies, bulk charge compensation, Hall transport measurements and surface quantum control. Our results reveal a spin-momentum locked Dirac cone carrying a nontrivial Berry’s phase that is nearly 100 per cent spin-polarized, which exhibits a tunable topological fermion density in the vicinity of the Kramers point and can be driven to the long-sought topological spin transport regime. The observed topological nodal state is shown to be protected even up to 300 K. Our demonstration of room-temperature topological order and non-trivial spintexture in stoichiometric Bi_2Se_3.M_x (M_x indicates surface doping or gating control) paves the way for future graphene-like studies of topological insulators, and applications of the observed spinpolarized edge channels in spintronic and computing technologies possibly at room temperature.

We have investigated the spin texture of surface Fermi arcs in the recently discovered Weyl semimetal TaAs using spin- and angle-resolved photoemission spectroscopy. The experimental results demonstrate that the Fermi arcs are spin-polarized. The measured spin texture fulfills the requirement of mirror and time reversal symmetries and is well reproduced by our first-principles calculations, which gives strong evidence for the topologically nontrivial Weyl semimetal state in TaAs. The consistency between the experimental and calculated results further confirms the distribution of chirality of the Weyl nodes determined by first-principles calculations., 4 figures, acceptance for publication in PRL, see also related papers arXiv:1501.00060, arXiv:1502.04684, arXiv:1503.09188

Using high-resolution angle-resolved photoemission spectroscopy (ARPES), surface states that were proposed to be useful for constructing the topological superconducting state in sodium cobaltates are experimentally explored. Two energy bands are observed to cross the Fermi level in the large x region. Through in situ surface electron doping, temperature-dependent ARPES measurements, and spin-resolved ARPES measurements, we demonstrate the existence of surface states due to less Na on the surface than in the bulk, as predicted in theory.

Quantum wires with spin-orbit coupling provide a unique opportunity to simultaneously control the coupling strength and the screened Coulomb interactions where new exotic phases of matter can be explored. Here we report on the observation of an exotic spin-orbit density wave in Pb-atomic wires on Si(557) surfaces by mapping out the evolution of the modulated spin-texture at various conditions with spin-and angle-resolved photoelectron spectroscopy. The results are independently quantified by surface transport measurements. The spin polarization, coherence length, spin dephasing rate and the associated quasiparticle gap decrease simultaneously as the screened Coulomb interaction decreases with increasing excess coverage, providing a new mechanism for generating and manipulating a spin-orbit entanglement effect via electronic interaction. Despite clear evidence of spontaneous spin-rotation symmetry breaking and modulation of spin-momentum structure as a function of excess coverage, the average spin polarization over the Brillouin zone vanishes, indicating that time-reversal symmetry is intact as theoretically predicted. DFG/FOR/1700 Swiss National Science Foundation

Rhizomania, one of the most devastating diseases in sugar beet, is caused by Beet Necrotic Yellow Vein Virus (BNYVV) belonging to the genus Benyvirus. Use of sugar beet varieties with resistance to BNYVV is generally considered as the only way to maintain a profitable yield on rhizomania-infested fields. As an alternative to natural resistance, we explored the transgenic expression of viral dsRNA for engineering resistance to rhizomania. Transgenic plants expressing an inverted repeat of a 0.4 kb fragment derived from the BNYVV replicase gene displayed high levels of resistance against different genetic strains of BNYVV when inoculated using the natural vector, Polymyxa betae. The resistance was maintained under high infection pressures and over prolonged growing periods in the greenhouse as well as in the field. Resistant plants accumulated extremely low amounts of transgene mRNA and high amounts of the corresponding siRNA in the roots, illustrative of RNA silencing as the underlying mechanism. The transgenic resistance compared very favourably to natural sources of resistance to rhizomania and thus offers an attractive alternative for breeding resistant sugar beet varieties.

Combining first-principles calculations and spin-and angle-resolved photoemission spectroscopy measurements, we identify the helical spin textures for three different Dirac cone states in the interfaced systems of a two-dimensional (2D) topological insulator (TI) of a Bi(111) bilayer and a three-dimensional (3D) TI B or Bi2Te3. The spin texture is found to be the same for the intrinsic Dirac cone of Bi2Te3 or Bi2Te3 surface states, the extrinsic Dirac cone of Bi bilayer induced by the Rashba effect, and the hybridized Dirac cone between the former two states. Further orbit-and atom-resolved analysis shows that s and p(z) orbits have a clockwise (counterclockwise) spin rotation tangent to the iso-energy contour of the upper (lower) Dirac cone, while p(x) and p(y) orbits have radial spin components. The Dirac cone states may reside on different atomic layers, but have the same spin texture. Our results suggest that the unique spin texture of Dirac cone states is a signature property of spin-orbit coupling, independent of topology.

Spin-orbit coupling has been conjectured to play a key role in the low-energy electronic structure of Sr2RuO4. By using circularly polarized light combined with spin- and angle-resolved photoemission spectroscopy, we directly measure the value of the effective spin-orbit coupling to be 130 � 30 meV. This is even larger than theoretically predicted and comparable to the energy splitting of the dxy and dxz;yz orbitals around the Fermi surface, resulting in a strongly momentum-dependent entanglement of spin and orbital character in the electronic wavefunction. As demonstrated by the spin expectation value h sk · s−ki calculated for a pair of electrons with zero total momentum, the classification of the Cooper pairs in terms of pure singlets or triplets fundamentally breaks down, necessitating a description of the unconventional superconducting state of Sr2RuO4 in terms of these newly found spin-orbital entangled eigenstates.

We report on the epitaxial fabrication and electronic properties of a topological phase in strained \alpha-Sn on InSb. The topological surface state forms in the presence of an unusual band order not based on direct spin-orbit coupling, as shown in density functional and GW slab-layer calculations. Angle-resolved photoemission including spin detection probes experimentally how the topological spin-polarized state emerges from the second bulk valence band. Moreover, we demonstrate the precise control of the Fermi level by dopants., Comment: version 2 with supplementary information

We present time-resolved photoemission experiments from a peculiar bismuth surface, Bi(114). The strong one-dimensional character of this surface is reflected in the Fermi surface, which consists of spin-polarized straight lines. Our results show that the depletion of the surface state and the population of the bulk conduction band after the initial optical excitation persist for very long times. The disequilibrium within the hot electron gas along with strong electron-phonon coupling cause a displacive excitation of coherent phonons, which in turn are reflected in coherent modulations of the electronic states. Beside the well-known A1g bulk phonon mode at 2.76 THz the time-resolved photoelectron spectra reveal a second mode at 0.72 THz which can be attributed to an optical surface phonon mode along the atomic rows of the Bi(114) surface., Comment: 5 pages, 4 figures

A topological insulator protected by time-reversal symmetry is realized via spin-orbit interaction-driven band inversion. The topological phase in the Bi(1-x)Sb(x) system is due to an odd number of band inversions. A related spin-orbit system, the Pb(1-x)Sn(x)Te, has long been known to contain an even number of inversions based on band theory. Here we experimentally investigate the possibility of a mirror symmetry-protected topological crystalline insulator phase in the Pb(1-x)Sn(x)Te class of materials that has been theoretically predicted to exist in its end compound SnTe. Our experimental results show that at a finite Pb composition above the topological inversion phase transition, the surface exhibits even number of spin-polarized Dirac cone states revealing mirror-protected topological order distinct from that observed in Bi(1-x)Sb(x). Our observation of the spin-polarized Dirac surface states in the inverted Pb(1-x)Sn(x)Te and their absence in the non-inverted compounds related via a topological phase transition provide the experimental groundwork for opening the research on novel topological order in quantum devices.

The spin texture of the metallic two-dimensional electron system (root3 x root3)-Au/Ge(111) is revealed by fully three-dimensional spin-resolved photoemission, as well as by density functional calculations. The large hexagonal Fermi surface, generated by the Au atoms, shows a significant splitting due to spin-orbit interactions. The planar components of the spin exhibit helical character, accompanied by a strong out-of-plane spin component with alternating signs along the six Fermi surface sections. Moreover, in-plane spin rotations towards a radial direction are observed close to the hexagon corners. Such a threefold-symmetric spin pattern is not described by the conventional Rashba model. Instead, it reveals an interplay with Dresselhaus-like spin-orbit effects as a result of the crystalline anisotropies., Comment: 5 pages, 4 figures, accepted at Physical Review Letters

Masteroppgave i bedriftsledelse (MBA) - Universitetet i Nordland, 2012 Tematisk omhandler denne oppgaven endringsprosesser i Karlsøy kommune i Troms fylke, og hvilke forhold som påvirker endringsprosesser i kommunen. Den overordnede problemstillingen ble innledningsvis formulert slik: Hva hemmer endringsprosesser i Karlsøy kommune? Tre underproblemstillinger ble videre definert i spørsmålsform: • Hvordan vurderes framtidens krav til organisasjonen? • Hvordan vurderes styrker og svakheter ved organisasjonen? • Hvordan ledes endringsprosessene i organisasjonen? Følgende forhold ser ut til å hemme endringsprosessen i Kommunen: • Beslutningssystemet trekker i retning av anarkistisk preg, ved at endringsprosessen fremstår som en arena for maktkamp. Dette underbygges ved oppfatninger og beskrivelser som karakteriserer forholdet mellom mål, middel og gjennomføring som uklar, vanskelig å gripe (komplekst) og mangelfullt definert. • Endringsprosessen i kommunen kan forklares både som utnyttelse og utforskning, men med størst forklaringskraft på utnyttelsesprosessen. En slik utnyttelse synes ikke å gi endringsprosessen den nødvendige drivkraft, atferd og kultur for å kunne understøtte de strategiske intensjoner med det formål å skape en endringskultur og utvikle visjonen i et lengre tidsperspektiv. • Funn trekker i retning av et todelt endringsperspektiv . Det konseptuelle endringsperspektivet synes å ha størst fokus i enhetene og i samhandlingen mellom enhetene, mens rasjonalisering mht organiseringen har fokus på rasjonaliseringsgevinster synes å ha størst fokus hos ledergruppa i kommunen. Dette gjør at kommunen som enhet ikke oppnår felles fokus på visjon og mål. Visjonen, målsettingene og eksterne kravene til kommunen gjør at endringsprosessen kan karakteriseres som en rasjonaliseringsprosess. Det er vanskelig å få gehør for eller å gjennomføre konseptuelle endringer på grunn av manglende forutsetninger og tilrettelegging. Endringsprosessen mangler konseptuel forankring hos ansatte. • Dagens organisasjon oppfattes å være rigid, fragmentert, relativt hierarkisk, regelstyrt og uoversiktlig. Dette tilrettelegger i liten grad for endringer tilpasset omgivelsens krav til fleksibilitet. Det eksisterer likevel endringsvilje mellom de enkelte enhetene i kommunen. • Endringsprosessen i kommunen oppfattes å være preget aven hard ledelsesstil, noe som ser ut til å redusere evnen til å skape en varig atferdsendring og reduserer endringsviljen. Samtidig må påstanden om hard lederstil modifiseres: lederstilen er rett nok knyttet til den pågående endringsprosessen. I et lengre tidsperspektiv, utenfor endringsprosessens arena og i den daglige drift oppfattes lederstilen som inkluderende. I den pågående endringsprosessen synes hovedfokuset å være på vertikal styring med rasjonaliseringsgevinster som mål, på bekostning av fokuset på mennesket i organisasjonen. Konsekvensen er økt motstand mot gjennomføring av de planlagte endringene.