Thermal Evolution of Dirac Magnons in the Honeycomb Ferromagnet CrBr_{3}.

CrBr_{3} is an excellent realization of the two-dimensional honeycomb ferromagnet, which offers a bosonic equivalent of graphene with Dirac magnons and topological character. We perform inelastic neutron scattering measurements using state-of-the-art instrumentation to update 50-year-old data, thereby enabling a definitive comparison both with recent experimental claims of a significant gap at the Dirac point and with theoretical predictions for thermal magnon renormalization. We demonstrate that CrBr_{3} has next-neighbor J_{2} and J_{3} interactions approximately 5% of J_{1}, an ideal Dirac magnon dispersion at the K point, and the associated signature of isospin winding. The magnon lifetime and the thermal band renormalization show the universal T^{2} evolution expected from an interacting spin-wave treatment, but the measured dispersion lacks the predicted van Hove features, pointing to the need for more sophisticated theoretical analysis.

Evidence for a Square-Square Vortex Lattice Transition in a High-T_{c} Cuprate Superconductor.

Using sound velocity and attenuation measurements in high magnetic fields, we identify a new transition in the vortex lattice state of La_{2-x}Sr_{x}CuO_{4}. The transition, observed in magnetic fields exceeding 35 T and temperatures far below zero field T_{c}, is detected in the compression modulus of the vortex lattice, at a doping level of x=p=0.17. Our theoretical analysis based on Eilenberger's theory of the vortex lattice shows that the transition corresponds to the long-sought 45° rotation of the square vortex lattice, predicted to occur in d-wave superconductors near a van Hove singularity.

The ontogeny of fairness in seven societies.

A sense of fairness plays a critical role in supporting human cooperation. Adult norms of fair resource sharing vary widely across societies, suggesting that culture shapes the acquisition of fairness behaviour during childhood. Here we examine how fairness behaviour develops in children from seven diverse societies, testing children from 4 to 15 years of age (n = 866 pairs) in a standardized resource decision task. We measured two key aspects of fairness decisions: disadvantageous inequity aversion (peer receives more than self) and advantageous inequity aversion (self receives more than a peer). We show that disadvantageous inequity aversion emerged across all populations by middle childhood. By contrast, advantageous inequity aversion was more variable, emerging in three populations and only later in development. We discuss these findings in relation to questions about the universality and cultural specificity of human fairness.

Thermal Control of Spin Excitations in the Coupled Ising-Chain Material RbCoCl_{3}.

We have used neutron spectroscopy to investigate the spin dynamics of the quantum (S=1/2) antiferromagnetic Ising chains in RbCoCl_{3}. The structure and magnetic interactions in this material conspire to produce two magnetic phase transitions at low temperatures, presenting an ideal opportunity for thermal control of the chain environment. The high-resolution spectra we measure of two-domain-wall excitations therefore characterize precisely both the continuum response of isolated chains and the "Zeeman-ladder" bound states of chains in three different effective staggered fields in one and the same material. We apply an extended Matsubara formalism to obtain a quantitative description of the entire dataset, Monte Carlo simulations to interpret the magnetic order, and finite-temperature density-matrix renormalization-group calculations to fit the spectral features of all three phases.

Giant Pressure Dependence and Dimensionality Switching in a Metal-Organic Quantum Antiferromagnet.

We report an extraordinary pressure dependence of the magnetic interactions in the metal-organic system [CuF_{2}(H_{2}O)_{2}]_{2}pyrazine. At zero pressure, this material realizes a quasi-two-dimensional spin-1/2 square-lattice Heisenberg antiferromagnet. By high-pressure, high-field susceptibility measurements we show that the dominant exchange parameter is reduced continuously by a factor of 2 on compression. Above 18 kbar, a phase transition occurs, inducing an orbital re-ordering that switches the dimensionality, transforming the quasi-two-dimensional lattice into weakly coupled chains. We explain the microscopic mechanisms for both phenomena by combining detailed x-ray and neutron diffraction studies with quantitative modeling using spin-polarized density functional theory.

Three-Dimensional Fermi Surface of Overdoped La-Based Cuprates.

We present a soft x-ray angle-resolved photoemission spectroscopy study of overdoped high-temperature superconductors. In-plane and out-of-plane components of the Fermi surface are mapped by varying the photoemission angle and the incident photon energy. No k_{z} dispersion is observed along the nodal direction, whereas a significant antinodal k_{z} dispersion is identified for La-based cuprates. Based on a tight-binding parametrization, we discuss the implications for the density of states near the van Hove singularity. Our results suggest that the large electronic specific heat found in overdoped La_{2-x}Sr_{x}CuO_{4} cannot be assigned to the van Hove singularity alone. We therefore propose quantum criticality induced by a collapsing pseudogap phase as a plausible explanation for observed enhancement of electronic specific heat.

Bound States and Field-Polarized Haldane Modes in a Quantum Spin Ladder.

The challenge of one-dimensional systems is to understand their physics beyond the level of known elementary excitations. By high-resolution neutron spectroscopy in a quantum spin-ladder material, we probe the leading multiparticle excitation by characterizing the two-magnon bound state at zero field. By applying high magnetic fields, we create and select the singlet (longitudinal) and triplet (transverse) excitations of the fully spin-polarized ladder, which have not been observed previously and are close analogs of the modes anticipated in a polarized Haldane chain. Theoretical modeling of the dynamical response demonstrates our complete quantitative understanding of these states.

Are there ethical differences between stopping and not starting blood safety measures?

BACKGROUND AND OBJECTIVES: Concern with the costs of blood safety is growing, which raises the question whether safety measures that reduce risk only marginally should be discontinued. Withdrawing such safety measures would allow reallocating resources to more efficient health care interventions, but it might raise moral objections. MATERIALS AND METHODS: This study evaluates two ethical arguments why discontinuing blood safety measures would be more objectionable than not implementing them. The first argument is that whereas withdrawing protective measures causes harm to patients, not starting protective measures 'merely' omits to prevent harm. The second argument is that patients who benefit from protective measures are historically entitled to the continuation of those protective measures. RESULTS: Both arguments are unconvincing. There is only a weak causal connection between removing blood safety measures and harms that transfusion recipients suffer. Moreover, patients are not entitled to the continuation of protective measures that prove very inefficient, unless applying these protective measures rectifies past injustice towards them. CONCLUSION: Unless stronger ethical objections can be found, blood system operators and regulators should be more willing to withdraw inefficient safety measures.

A practice-based clinical evaluation of the survival and success of metal-ceramic and zirconia molar crowns: 5-year results.

This practice-based study evaluates the survival and success of conventionally luted metal-ceramic and zirconia molar crowns fabricated by using a prolonged cooling period for the veneering porcelain. Fifty-three patients were treated from 07/2008 to 07/2009 with either metal-ceramic crowns (MCC) or zirconia crowns (ZC). Forty-five patients (26 female) with 91 restorations (obser-vational period: 64.0 ± 4.8 months) participated in a clinical follow-up examination and were included in the study. Estimated cumulative survival (ECSv), success (ECSc) and veneering ceramic success (ECVCSc) were calculated (Kaplan-Meier) and analysed by the crown fabrication technique and the position of the restoration (Cox regression model) (P < 0.05). Five complete failures (MCC: 2, ZC: 3) were recorded (5-year ECSv: MCC: 97.6%, (95% confidence interval (95%-CI): [93%; 100%]/ZC: 94.0%, (95%-CI): [87%; 100%]). Of the MCCs (n = 41), 85.0%, [95%-CI: (77%; 96%)] remained event-free, whereas the ECSc for the ZCs (n = 50) was 74.3% (95%-CI): [61%; 87%]. No significant differences in ECSv (P = 0.51), ECSc (P = 0.43) and ECVCSc (P = 0.36) were detected between the two fabrication techniques. Restorations placed on terminal abutments (n = 44) demonstrated a significantly lower ECVCSc (P = 0.035), (5-year VCF-rate: 14.8%) than crowns placed on tooth-neighboured abutments (n = 47), (5-year VCF-rate: 4.3%). In the present study, zirconia molar crowns demonstrated a 5-year ECSv, ECSc and ECVCSc comparable to MCCs. Irrespective of the fabrication technique, crowns on terminal abutments bear a significantly increased risk for VCFs. Clinical investigations with an increased number of restorations are needed.

[Diagnosis and Therapeutic Interventions in Autism Spectrum Disorders in Adulthood]. / Zur Diagnostik und Behandlung von Autismus-Spektrum-Störungen im Erwachsenenalter.

Autism spectrum disorders (ASD) are characterized by disturbed social interaction and communication as well as stereotyped or repetitive behaviors and interests. Although adults with ASD often acquire complex compensatory strategies that help them master social situations in a rule-based fashion, they still show impairments in intuitive processing of social signals and especially nonverbal communication in complex everyday situations. This constitutes a particular challenge for the psychotherapy of ASD. Psychotherapists are required to explicitly inform and act as an agent of the non-autistic world to enable patients to acquire the ability to take different perspectives. The overall aim of cognitive behavioral therapy interventions addressing ASD in adulthood is to extend the patients' behavioral repertoire to improve their quality of life. Thus, besides psychoeducation on ASD and its frequently associated comorbidities, psychotherapy for adults with ASD should focus on the training and development of social-communicative skills. Furthermore, dealing with stress in everyday situations is an important aspect of psychotherapy of these patients.

Polymorphism in NFKBIA gene is associated with recurrent acute rejections in liver transplant recipients.

The nuclear factor of kappa light polypeptide gene enhancer B-cells inhibitor-alpha (NFKBIA) gene encodes a member of the nuclear factor-kappa-B inhibitor family. Polymorphisms in this gene might be associated with a susceptibility to acute rejection episodes following liver transplantation, as they may cause an increased activation level of the proinflammatory transcription factor nuclear factor of kappa light polypeptide gene enhancer in B-cells (NFκB). The aim of this study was to evaluate whether the NFKBIA polymorphisms -297 C/T (rs2233409), -826 C/T (rs2233406) and 126 G/A (rs696) affect the incidence of acute liver graft rejection. A total of 199 liver transplant recipients was analyzed, 100 without (NAR) and 99 with early acute rejection (AR). Thirty-two individuals with multiple acute rejections (MAR) were analyzed as a subgroup of AR. Polymerase chain reaction-allele specific restriction enzyme analysis (PCR-ASRA) and allele-specific hybridization with fluorescence resonance energy transfer (FRET) were used for genotyping. We identified the genotype NFKBIA 126 AA (P = 0.002) as well as the haplotype NFKBIA-126A-297T-826T (P = 0.002) as a potential risk factor for the occurrence of recurrent acute rejections. Furthermore, we assessed an association between the 126 A allele and susceptibility to recurrent acute rejections (P = 0.027). Our data suggest that the NFKBIA 126 G/A polymorphism might be potentially helpful to identify liver transplant recipients with an increased susceptibility to develop recurrent acute rejections.

Improving topical non-melanoma skin cancer treatment: In vitro efficacy of a novel guanosine-analog phosphonate.

Actinic keratosis, a frequent carcinoma in situ of non-melanoma skin cancer (NMSC), can transform into life-threatening cutaneous squamous cell carcinoma. Current treatment is limited due to low complete clearance rates and asks for novel therapeutic concepts; the novel purine nucleotide analogue OxBu may be an option. In order to enhance skin penetration, solid lipid nanoparticles (SLN, 136-156 nm) were produced with an OxBu entrapment efficiency of 96.5 ± 0.1%. For improved preclinical evaluation, we combined tissue engineering with clinically used keratin-18 quantification. Three doses of 10(-3) mol/l OxBu, dissolved in phosphate-buffered saline as well as loaded to SLN, were effective on reconstructed NMSC. Tumour response and apoptosis induction were evaluated by an increase in caspase-cleaved fragment of keratin-18, caspase-7 activation as well as by reduced expression of matrix metallopeptidase-2 and Ki-67. OxBu efficacy was superior to equimolar 5-fluorouracil solution, and thus the drug should be subjected to the next step in preclinical evaluation.

Dairy farming technologies and the agency of cows.

Studies on animal cognition, emotion, language, culture, and politics have shown that non-human animals are agents who engage in self-willed actions and have an interest in shaping their own lives. In today's world, however, animals' lives are affected significantly by circumstances that humans have created, including animal farming systems. The current paper explores how the agency of cows relates to technology by reporting on fieldwork performed in the Dutch dairy sector. Multi-species ethnography was used as a flexible methodology that allowed readjusting questions and methods as our research developed. In the first research phase, observations and informal talks were held on six farms which had been recruited on the basis of convenience sampling and which were each visited for one full day. In the second research phase, five more farms were selected for 1-day visits through theoretical and snowball sampling, and one farm was visited repeatedly for in-depth observations. The observational strategies used included following individual actors (farmers, cows or technologies) and documenting their interactions with other actors; participating in daily routines such as feeding cows roughage and scraping manure; witnessing cows' responses to non-routine events such as the introduction of new technologies or new cows; and sometimes waiting for notable occurrences by just 'hanging out' with cows. Observations and informal talks were in this research phase complemented by a small number of interviews with farmers, cow shed designers, and technology developers. Our main conclusion is that the agency of dairy cows is presupposed and mediated by dairy farming technologies. Dairy farming technologies presuppose cow in the 'scripts' and 'programs of action' which they enforce: they require cows to act in specific ways, anticipate some ways in which cows could disrupt technological routines, and (successfully or unsuccessfully) attempt to ensure cows' cooperation by appealing to their wants and desires and their ability to learn. Dairy farming technologies thus assign to cows not only the ability to perform 'metabolic labour' but also the capacity to act purposively and learning abilities. Technologies mediate cow agency by (co-)shaping how cows express agency in relation to other entities, including other cows, humans, other non-human animals, material entities including technologies, and the world at large. That technologies can be relevant for animal agency in various ways raises the question of how technologies can be designed for agency - although the concept of animal agency also challenges us to reconsider animal agriculture more fundamentally.

Knudsen effusion mass spectrometric determination of the complex vapor composition of samarium, europium, and ytterbium bromides.

RATIONALE: The vaporization of Sm, Eu, and Yb tri- and dibromides is accompanied by decomposition and disproportionation reactions. These result in complex vapor compositions whose analysis is an intricate problem for experimentalists. Approaches have been developed to interpret mass spectra and accurately determine the vapor composition of thermally unstable compounds. METHODS: A sector type magnet instrument was used. A combined ion source allowed the study of both the molecular and ionic vapor compositions in the electron ionization (EI) and the thermionic emission (TE) modes. The methodological approaches were based on a joint analysis of the ionization efficiency functions, the temperature and time dependences of the ion currents, and special mathematical data evaluation. RESULTS: The vaporization of SmBr3 , YbBr3 , SmBr2 , EuBr2 , and YbBr2 was studied in the temperature range of 850-1300 K. An initial stage of incongruent vaporization was observed in the case of the tribromides, SmBr2 , and YbBr2 . This eventually changed to a congruent vaporization stage. Various neutral (Ln, Br, Br2 , LnBr, LnBr2 , LnBr3 , Ln2 Br4 , Ln2 Br5 , and Ln2 Br6 ) and charged (Br(-), LnBr3 (-), LnBr4 (-)) species were detected at different vaporization stages. CONCLUSIONS: The quantitative vapor composition of Sm, Eu, and Yb tri- and dibromides was determined. It was found that only EuBr2 was stable in the studied temperature range. The developed approaches can be useful in the case of other thermally unstable compounds.

[Incidence of, risk factors for, and prevention of intestinal leakage]. / Inzidenz, Risikofaktoren und Prävention der intestinalen Nahtinsuffizienz.

BACKGROUND: Intestinal anastomotic leakage represents a major complication in visceral surgery with relevant morbidity and mortality. MATERIAL AND METHODS: Based on a literature -search in Medline / PubMed the available data are presented, critically reviewed and summarised. RESULTS AND CONCLUSION: Beside optimisation of surgical technique, patient-dependent risk factors - such as relevant comorbidity, certain medications or previous radiochemotherapy - play a major role in the development of anastomotic leak-age. The effort for optimisation of these patient-dependent risk factors is not incorporated within the compensation scheme in German hospitals.

Moral Intuitions About Stigmatizing Practices and Feeding Stigmatizing Practices: How Haidt's Moral Foundations Theory Relates to Infectious Disease Stigma.

Despite extensive stigma mitigation efforts, infectious disease stigma remains common. So far, little attention has been paid to the moral psychology of stigmatizing practices (i.e. beliefs, attitudes, actions) rather than the experience of being stigmatized. Addressing the moral psychology behind stigmatizing practices seems necessary to explain the persistence of infectious disease stigma and to develop effective mitigation strategies. Our article proposes building on Jonathan Haidt's moral foundations theory, which states that moral judgements follow from intuitions rather than conscious reasoning. Conceptual analysis was conducted to show how Haidt's five moral foundations can be connected to (i) moral judgements about stigmatizing practices and (ii) stigmatizing practices themselves. We found that care/harm, fairness/cheating, loyalty/betrayal and sanctity/degradation intuitions can inform moral judgements about stigmatizing practices. Loyalty/betrayal and sanctity/degradation intuitions can sometimes also feed stigmatizing practices. Authority/subversion intuitions can inform moral judgements and stigmatizing practices towards people who disrespect authoritative rules meant to protect public health. Moral dumbfounding and posthoc reasoning might explain the persistence of stigmatizing practices. In conclusion, this study demonstrates the relevance of Haidt's approach to infectious disease stigma research and mitigation strategies. We hope that this study motivates researchers to further test and assess this approach.

Small-scale farmer responses to the double exposure of climate change and market integration.

Anthropologists have long studied how small-scale societies manage climate variation. Here, we investigate how Yucatec Maya subsistence farmers respond to climate stress, and the ways in which market integration may enhance or disturb response stategies. Using information on harvest returns, climate perceptions, household economics and helping networks, modelling results show that as farmers rely more on market inputs (e.g. seed, tractors, fertilizer) for a successful yield, the reasons given for a bad harvest shift from climate variables to access to quality inputs. We also find that social and economic diversification is key to mediating a household's experience of climate and market shocks. The Maya are astute stewards of climate knowledge, and have effective social and economic means to mitigate potential fluctuations in food availability. In the transition from a subsistence to a market integrated economy, these traditional strategies become strained. Reliance on market inputs forges a more rigid food production system that conflicts with the diversity and flexibility on which traditional strategies depend to manage climate variation. Moving forward, the best policies would be those that facilitate maintaining an equal footing in both a subsistence maize economy, while incorporating new market opportunities. This article is part of the theme issue 'Climate change adaptation needs a science of culture'.

Comparison of pollen gene flow among four European beech (Fagus sylvatica L.) populations characterized by different management regimes.

The study of the dispersal capability of a species can provide essential information for the management and conservation of its genetic variability. Comparison of gene flow rates among populations characterized by different management and evolutionary histories allows one to decipher the role of factors such as isolation and tree density on gene movements. We used two paternity analysis approaches and different strategies to handle the possible presence of genotyping errors to obtain robust estimates of pollen flow in four European beech (Fagus sylvatica L.) populations from Austria and France. In each country one of the two plots is located in an unmanaged forest; the other plots are managed with a shelterwood system and inside a colonization area (in Austria and France, respectively). The two paternity analysis approaches provided almost identical estimates of gene flow. In general, we found high pollen immigration (~75% of pollen from outside), with the exception of the plot from a highly isolated forest remnant (~50%). In the two unmanaged plots, the average within-population pollen dispersal distances (from 80 to 184 m) were higher than previously estimated for beech. From the comparison between the Austrian managed and unmanaged plots, that are only 500 m apart, we found no evidence that either gene flow or reproductive success distributions were significantly altered by forest management. The investigated phenotypic traits (crown area, height, diameter and flowering phenology) were not significantly related with male reproductive success. Shelterwood seems to have an effect on the distribution of within-population pollen dispersal distances. In the managed plot, pollen dispersal distances were shorter, possibly because adult tree density is three-fold (163 versus 57 trees per hectare) with respect to the unmanaged one.

Automatic section thickness determination using an absolute gradient focus function.

Quantitative analysis of microstructures using computerized stereology systems is an essential tool in many disciplines of bioscience research. Section thickness determination in current nonautomated approaches requires manual location of upper and lower surfaces of tissue sections. In contrast to conventional autofocus functions that locate the optimally focused optical plane using the global maximum on a focus curve, this study identified by two sharp 'knees' on the focus curve as the transition from unfocused to focused optical planes. Analysis of 14 grey-scale focus functions showed, the thresholded absolute gradient function, was best for finding detectable bends that closely correspond to the bounding optical planes at the upper and lower tissue surfaces. Modifications to this function generated four novel functions that outperformed the original. The 'modified absolute gradient count' function outperformed all others with an average error of 0.56 µm on a test set of images similar to the training set; and, an average error of 0.39 µm on a test set comprised of images captured from a different case, that is, different staining methods on a different brain region from a different subject rat. We describe a novel algorithm that allows for automatic section thickness determination based on just out-of-focus planes, a prerequisite for fully automatic computerized stereology.