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result(s) for
"Lang, Martin"
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Bs → μ+μ− in a two-Higgs-doublet model with flavour-changing up-type Yukawa couplings
2024
A
bstract
We present a Two-Higgs-Doublet Model in which the structure of the quark Yukawa matrices is governed by three spurions breaking the flavour symmetries of the quark Yukawa sector. The model naturally suppresses flavour-changing neutral current (FCNC) amplitudes in the down-type sector, but permits sizable FCNC couplings in the up sector. We calculate the branching ratio of
B
s
→ μ
+
μ
−
to leading and next-to-leading order of QCD for the case with FCNC couplings of the heavy neutral Higgs bosons to up-type quarks and verify that all counterterms follow the pattern dictated by the spurion expansion of the Yukawa matrices. We find correlations between
B
s
→ μ
+
μ
−
,
b → sγ
, and the Higgs masses. The
mixing amplitude is naturally suppressed in the model but can probe a portion of the parameter space with very heavy Higgs bosons.
Journal Article
Bloch points in nanostrips
by
Fangohr, Hans
,
Lang, Martin
,
Hovorka, Ondrej
in
639/301/357/997
,
639/705/1042
,
639/766/119/997
2023
Complex magnetic materials hosting topologically non-trivial particle-like objects such as skyrmions are under intensive research and could fundamentally change the way we store and process data. One important class of materials are helimagnetic materials with Dzyaloshinskii-Moriya interaction. Recently, it was demonstrated that thin nanodisks consisting of two layers with opposite chirality can host a single stable Bloch point of two different types at the interface between the layers. Using micromagnetic simulations we show that FeGe nanostrips consisting of two layers with opposite chirality can host multiple coexisting Bloch points in an arbitrary combination of the two different types. We show that the number of Bloch points that can simultaneously coexist depends on the strip geometry and the type of the individual Bloch points. Our simulation results allow us to predict strip geometries suitable for an arbitrary number of Bloch points. We show an example of an 80-Bloch-point configuration verifying the prediction.
Journal Article
HQET sum rules for matrix elements of dimension-six four-quark operators for meson lifetimes within and beyond the Standard Model
by
Wüthrich, Zachary
,
Black, Matthew
,
Lang, Martin
in
Asymmetry
,
Bottom Quarks
,
Classical and Quantum Gravitation
2025
A
bstract
Theory predictions of heavy-hadron lifetime ratios critically depend on precise determinations of the dimension-six spectator effects arising from the double insertion of the weak effective |∆
B
| = 1 Hamiltonian. In the presence of beyond-standard-model (BSM) operators, the resulting ∆
B
= 0 Hamiltonian features additional four-quark operators whose matrix elements need to be determined using non-perturbative methods. We present for the first time results for the non-perturbative hadronic matrix elements of the four-quark operators relevant for the description of the meson lifetime ratio
τ
(
B
+
) /
τ
(
B
d
), obtained using heavy-quark effective theory (HQET) sum rules with the full BSM effective Hamiltonian. In addition, we recompute and update the bag parameters for the Standard Model operators.
Journal Article
Effects of predictable behavioral patterns on anxiety dynamics
2022
People face stressors that are beyond their control and that maladaptively perpetuate anxiety. In these contexts, rituals emerge as a natural coping strategy helping decrease excessive anxiety. However, mechanisms facilitating these purported effects have rarely been studied. We hypothesized that repetitive and rigid ritual sequences help the human cognitive-behavioral system to return to low-entropy states and assuage anxiety. This study reports a pre-registered test of this hypothesis using a Czech student sample (n = 268). Participants were exposed to an anxiety induction and then randomly assigned to perform one of three actions: ritualized, control, and neutral (no-activity). We assessed the effects of this manipulation on cognitive and physiological anxiety, finding that ritualized action positively affected anxiety decrease, but this decrease was only slightly larger than in the other two conditions. Nevertheless, the between-condition differences in the reduction of physiological anxiety were well-estimated in participants more susceptible to anxiety induction.
Journal Article
Crosstalk of organelles in Parkinson’s disease – MiT family transcription factors as central players in signaling pathways connecting mitochondria and lysosomes
by
Pramstaller, Peter P.
,
Lang, Martin
,
Pichler, Irene
in
Adaptation
,
Alzheimer's disease
,
Animal models
2022
Living organisms constantly need to adapt to their surrounding environment and have evolved sophisticated mechanisms to deal with stress. Mitochondria and lysosomes are central organelles in the response to energy and nutrient availability within a cell and act through interconnected mechanisms. However, when such processes become overwhelmed, it can lead to pathologies. Parkinson’s disease (PD) is a common neurodegenerative disorder (NDD) characterized by proteinaceous intracellular inclusions and progressive loss of dopaminergic neurons, which causes motor and non-motor symptoms. Genetic and environmental factors may contribute to the disease etiology. Mitochondrial dysfunction has long been recognized as a hallmark of PD pathogenesis, and several aspects of mitochondrial biology are impaired in PD patients and models. In addition, defects of the autophagy-lysosomal pathway have extensively been observed in cell and animal models as well as PD patients’ brains, where constitutive autophagy is indispensable for adaptation to stress and energy deficiency. Genetic and molecular studies have shown that the functions of mitochondria and lysosomal compartments are tightly linked and influence each other. Connections between these organelles are constituted among others by mitophagy, organellar dynamics and cellular signaling cascades, such as calcium (Ca
2+
) and mTOR (mammalian target of rapamycin) signaling and the activation of transcription factors. Members of the Microphthalmia-associated transcription factor family (MiT), including MITF, TFE3 and TFEB, play a central role in regulating cellular homeostasis in response to metabolic pressure and are considered master regulators of lysosomal biogenesis. As such, they are part of the interconnection between mitochondria and lysosome functions and therefore represent attractive targets for therapeutic approaches against NDD, including PD. The activation of MiT transcription factors through genetic and pharmacological approaches have shown encouraging results at ameliorating PD-related phenotypes in in vitro and in vivo models. In this review, we summarize the relationship between mitochondrial and autophagy-lysosomal functions in the context of PD etiology and focus on the role of the MiT pathway and its potential as pharmacological target against PD.
Journal Article
Imputation-powered whole-exome analysis identifies genes associated with kidney function and disease in the UK Biobank
by
Göcmen, Burulca
,
Li, Yong
,
Katsara, Maria-Alexandra
in
49/23
,
631/208/205/2138
,
692/4022/1585/104
2023
Genome-wide association studies have discovered hundreds of associations between common genotypes and kidney function but cannot comprehensively investigate rare coding variants. Here, we apply a genotype imputation approach to whole exome sequencing data from the UK Biobank to increase sample size from 166,891 to 408,511. We detect 158 rare variants and 105 genes significantly associated with one or more of five kidney function traits, including genes not previously linked to kidney disease in humans. The imputation-powered findings derive support from clinical record-based kidney disease information, such as for a previously unreported splice allele in
PKD2
, and from functional studies of a previously unreported frameshift allele in
CLDN10
. This cost-efficient approach boosts statistical power to detect and characterize both known and novel disease susceptibility variants and genes, can be generalized to larger future studies, and generates a comprehensive resource (
https://ckdgen-ukbb.gm.eurac.edu/
) to direct experimental and clinical studies of kidney disease.
An exome wide association study of UK Biobank data revealed 158 variants and 105 genes significantly associated with kidney function traits and disease. The findings are supported by functional evidence for a previously unreported mutation in CLDN10.
Journal Article
The longitudinal associations of material security and belief in God in young Americans
2026
The prevalence of religious beliefs and practices is puzzling from an evolutionary perspective, but previous research has suggested that religious traditions may provide cooperative benefits and improve well-being. Seemingly in contrast to this claim are worldwide secularization trends in which people disaffiliate from religions and abandon belief in God. Theorists have suggested that diminished pressures on cooperation and well-being no longer motivate individuals to seek religious benefits and pay the associated participation costs. We investigate this claim using the National Study of Youth and Religion dataset, which tracks the development of religiosity among US Christians from adolescence to young adulthood ( n = 3,370). Using a lagged panel design, we found that material security in Wave 1 (early adolescence) predicts a decrease in belief in God in Wave 4 (young adulthood), although this association is rather small. This result provides some support for the hypothesis that participation in religious traditions is associated with living in an insecure socio-ecology, where religious systems may still confer benefits on their members; yet it is not the only driver of secularization. We conclude with a call for further research using more nuanced measures and larger sample sizes to provide deeper insights into the potentially adaptive nature of cultural systems.
Journal Article
The reference human nuclear mitochondrial sequences compilation validated and implemented on the UCSC genome browser
by
Attimonelli, Marcella
,
Calabrese, Francesco Maria
,
Lang, Martin
in
Animal Genetics and Genomics
,
Biomedical and Life Sciences
,
Cell Nucleus - metabolism
2011
Background
Eukaryotic nuclear genomes contain fragments of mitochondrial DNA called NumtS (Nuclear mitochondrial Sequences), whose mode and time of insertion, as well as their functional/structural role within the genome are debated issues. Insertion sites match with chromosomal breaks, revealing that micro-deletions usually occurring at non-homologous end joining
loci
become reduced in presence of NumtS. Some NumtS are involved in recombination events leading to fragment duplication. Moreover, NumtS are polymorphic, a feature that renders them candidates as population markers. Finally, they are a cause of contamination during human mtDNA sequencing, leading to the generation of false heteroplasmies.
Results
Here we present RHNumtS.2, the most exhaustive human NumtSome catalogue annotating 585 NumtS, 97% of which were here validated in a European individual and in HapMap samples. The NumtS complete dataset and related features have been made available at the UCSC Genome Browser. The produced sequences have been submitted to INSDC databases. The implementation of the RHNumtS.2 tracks within the UCSC Genome Browser has been carried out with the aim to facilitate browsing of the NumtS tracks to be exploited in a wide range of research applications.
Conclusions
We aimed at providing the scientific community with the most exhaustive overview on the human NumtSome, a resource whose aim is to support several research applications, such as studies concerning human structural variation, diversity, and disease, as well as the detection of false heteroplasmic mtDNA variants. Upon implementation of the NumtS tracks, the application of the BLAT program on the UCSC Genome Browser has now become an additional tool to check for heteroplasmic artefacts, supported by data available through the NumtS tracks.
Journal Article
Controlling stable Bloch points with electric currents
by
Holt, Samuel J. R.
,
Fangohr, Hans
,
Lang, Martin
in
639/301/357/997
,
639/705/1042
,
639/766/119/997
2023
The Bloch point is a point singularity in the magnetisation configuration, where the magnetisation vanishes. It can exist as an equilibrium configuration and plays an important role in many magnetisation reversal processes. In the present work, we focus on manipulating Bloch points in a system that can host stable Bloch points—a two-layer FeGe nanostrip with opposite chirality of the two layers. We drive Bloch points using spin-transfer torques and find that Bloch points can move collectively without any Hall effect and report that Bloch points are repelled from the sample boundaries and each other. We study pinning of Bloch points at wedge-shaped constrictions (notches) in the nanostrip and demonstrate that arrays of Bloch points can be moved past a series of notches in a controlled manner by applying consecutive current pulses of different strength. Finally, we simulate a T-shaped geometry and demonstrate that a Bloch point can be moved along different paths by applying current between suitable strip ends.
Journal Article
A comparison of self-report, systematic observation and third-party judgments of church attendance in a rural Fijian Village
2021
Social desirability reporting leads to over estimations of church attendance. To date, researchers have treated over-reporting of church attendance as a general phenomenon, and have been unable to determine the demographic correlates of inaccuracy in these self-reports. By comparing over eight months of observational data on church attendance (n = 48 services) to self-report in a rural Fijian village, we find that 1) self-report does not reliably predict observed attendance, 2) women with two or more children (≥ 2) are more likely to over-report their attendance than women with fewer children (≤ 1), and 3) self-report of religiosity more reliably predicts observed church attendance than does self-report of church attendance. Further, we find that third-party judgements of church attendance by fellow villagers are more reliably associated with observed church attendance than self-report. Our findings suggest that researchers interested in estimating behavioral variation, particularly in domains susceptible to social desirability effects, should consider developing and employing third-party methods to mitigate biases inherent to self-report.
Journal Article