bluuebunny/crossref_metadata_2025 huggingface dataset:
A peptide-neurotensin conjugate that crosses the blood-brain barrier induces pharmacological hypothermia associated with anticonvulsant, neuroprotective and anti-inflammatory properties following status epilepticus in mice
Authors: Ferhat Lotfi , Soussi Rabia , Masse Maxime , Kyriatzis Grigorios , Girard Stéphane D , Gassiot Fanny , Gaudin Nicolas , Laurencin Mathieu , Bernard Anne , Bôle Angélique , Ferracci Géraldine , Smirnova Maria , Roman François , Dive Vincent , Cisternino Salvatore , Temsamani Jamal , David Marion , Lécorché Pascaline , Jacquot Guillaume , Khrestchatisky Michel
Published: August 2024

Preclinical and clinical studies show that mild to moderate hypothermia is neuroprotective in sudden cardiac arrest, ischemic stroke, perinatal hypoxia/ischemia, traumatic brain injury and seizures. Induction of hypothermia largely involves physical cooling therapies, which induce several clinical complications, while some molecules have shown to be efficient in pharmacologically-induced hypothermia (PIH). Neurotensin (NT), a 13 amino-acid neuropeptide that regulates body temperature, interacts with various receptors to mediate its peripheral and central effects. NT induces PIH when administered intracerebrally. However, these effects are not observed if NT is administered peripherally, due to its rapid degradation and poor passage of the blood brain barrier (BBB). We conjugated NT to peptides that bind the low-density lipoprotein receptor (LDLR) to generate “vectorized” forms of NT with enhanced BBB permeability. We evaluated their effects in epileptic conditions following peripheral administration. One of these conjugates, VH-N412, displayed improved stability, binding potential to both the LDLR and NTSR-1, rodent/human cross-reactivity and improved brain distribution. In a mouse model of kainate (KA)-induced status epilepticus (SE), VH-N412 elicited rapid hypothermia associated with anticonvulsant effects, potent neuroprotection and reduced hippocampal inflammation. VH-N412 also reduced sprouting of the dentate gyrus mossy fibers and preserved learning and memory skills in the treated mice. In cultured hippocampal neurons, VH-N412 displayed temperature-independent neuroprotective properties. To the best of our knowledge, this is the first report describing the successful treatment of SE with PIH. In all, our results show that vectorized NT may elicit different neuroprotection mechanisms mediated either by hypothermia and/or by intrinsic neuroprotective properties.
A peptide-neurotensin conjugate that crosses the blood-brain barrier induces pharmacological hypothermia associated with anticonvulsant, neuroprotective and anti-inflammatory properties following status epilepticus in mice
Authors: Ferhat Lotfi , Soussi Rabia , Masse Maxime , Kyriatzis Grigorios , Girard Stéphane D , Gassiot Fanny , Gaudin Nicolas , Laurencin Mathieu , Bernard Anne , Bôle Angélique , Ferraci Géraldine , Smirnova Maria , Roman François , Dive Vincent , Cisternino Salvatore , Temsamani Jamal , David Marion , Lécorché Pascaline , Jacquot Guillaume , Khrestchatisky Michel
Published: August 2024

Preclinical and clinical studies show that mild to moderate hypothermia is neuroprotective in sudden cardiac arrest, ischemic stroke, perinatal hypoxia/ischemia, traumatic brain injury and seizures. Induction of hypothermia largely involves physical cooling therapies, which induce several clinical complications, while some molecules have shown to be efficient in pharmacologically-induced hypothermia (PIH). Neurotensin (NT), a 13 amino-acid neuropeptide that regulates body temperature, interacts with various receptors to mediate its peripheral and central effects. NT induces PIH when administered intracerebrally. However, these effects are not observed if NT is administered peripherally, due to its rapid degradation and poor passage of the blood brain barrier (BBB). We conjugated NT to peptides that bind the low-density lipoprotein receptor (LDLR) to generate “vectorized” forms of NT with enhanced BBB permeability. We evaluated their effects in epileptic conditions following peripheral administration. One of these conjugates, VH-N412, displayed improved stability, binding potential to both the LDLR and NTSR-1, rodent/human cross-reactivity and improved brain distribution. In a mouse model of kainate (KA)-induced status epilepticus (SE), VH-N412 elicited rapid hypothermia associated with anticonvulsant effects, potent neuroprotection and reduced hippocampal inflammation. VH-N412 also reduced sprouting of the dentate gyrus mossy fibers and preserved learning and memory skills in the treated mice. In cultured hippocampal neurons, VH-N412 displayed temperature-independent neuroprotective properties. To the best of our knowledge, this is the first report describing the successful treatment of SE with PIH. In all, our results show that vectorized NT may elicit different neuroprotection mechanisms mediated either by hypothermia and/or by intrinsic neuroprotective properties.
Structure transfer and consolidation in visual implicit learning
Authors: Garber Dominik , Fiser József
Published: August 2024

Transfer learning, the re-application of previously learned higher-level regularities to novel input, is a key challenge in cognition. While previous empirical studies investigated human transfer learning in supervised or reinforcement learning for explicit knowledge, it is unknown whether such transfer occurs during naturally more common implicit and unsupervised learning and if so, how it is related to memory consolidation. We compared the transfer of newly acquired explicit and implicit abstract knowledge during unsupervised learning by extending a visual statistical learning paradigm to a transfer learning context. We found transfer during unsupervised learning but with important differences depending on the explicitness/implicitness of the acquired knowledge. Observers acquiring explicit knowledge during initial learning could transfer the learned structures immediately. In contrast, observers with the same amount but implicit knowledge showed the opposite effect, a structural interference during transfer. However, with sleep between the learning phases, implicit observers switched their behaviour and showed the same pattern of transfer as explicit observers did while still remaining implicit. This effect was specific to sleep and not found after non-sleep consolidation. Our results highlight similarities and differences between explicit and implicit learning while acquiring generalizable higher-level knowledge and relying on consolidation for restructuring internal representations.
Auditory confounds can drive online effects of transcranial ultrasonic stimulation in humans
Authors: Kop Benjamin R , Shamli Oghli Yazan , Grippe Talyta C , Nandi Tulika , Lefkes Judith , Meijer Sjoerd W , Farboud Soha , Engels Marwan , Hamani Michelle , Null Melissa , Radetz Angela , Hassan Umair , Darmani Ghazaleh , Chetverikov Andrey , den Ouden Hanneke EM , Bergmann Til Ole , Chen Robert , Verhagen Lennart
Published: August 2024

Transcranial ultrasonic stimulation (TUS) is rapidly emerging as a promising non-invasive neuromodulation technique. TUS is already well-established in animal models, providing foundations to now optimize neuromodulatory efficacy for human applications. Across multiple studies, one promising protocol, pulsed at 1000 Hz, has consistently resulted in motor cortical inhibition in humans (Fomenko et al., 2020). At the same time, a parallel research line has highlighted the potentially confounding influence of peripheral auditory stimulation arising from TUS pulsing at audible frequencies. In this study, we disentangle direct neuromodulatory and indirect auditory contributions to motor inhibitory effects of TUS. To this end, we include tightly matched control conditions across four experiments, one preregistered, conducted independently at three institutions. We employed a combined transcranial ultrasonic and magnetic stimulation paradigm, where TMS-elicited motor-evoked potentials (MEPs) served as an index of corticospinal excitability. First, we replicated motor inhibitory effects of TUS but showed through both tight controls and manipulation of stimulation intensity, duration, and auditory masking conditions that this inhibition was driven by peripheral auditory stimulation, not direct neuromodulation. Furthermore, we consider neuromodulation beyond driving overall excitation/inhibition and show preliminary evidence of how TUS might interact with ongoing neural dynamics instead. Primarily, this study highlights the substantial shortcomings in accounting for the auditory confound in prior TUS-TMS work where only a flip-over sham and no active control was used. The field must critically reevaluate previous findings given the demonstrated impact of peripheral confounds. Furthermore, rigorous experimental design via (in)active control conditions is required to make substantiated claims in future TUS studies. Only when direct effects are disentangled from those driven by peripheral confounds can TUS fully realize its potential for research and clinical applications.
Robust Optogenetic Inhibition with Red-light-sensitive Anion-conducting Channelrhodopsins
Authors: Oppermann Johannes , Rozenberg Andrey , Fabrin Thomaz , González-Cabrera Cristian , Parker Rafael ES , Béjà Oded , Prigge Matthias , Hegemann Peter
Published: August 2024

Channelrhodopsins (ChRs) are light-gated ion channels widely used to optically activate or silence selected electrogenic cells, such as individual brain neurons. Here, we describe identifying and characterizing a set of anion-conducting ChRs (ACRs) from diverse taxa and representing various branches of the ChR phylogenetic tree. The
Mantoniella squamata
ACR (MsACR1) showed high sensitivity to yellow-green light (λ
max
at 555 nm) and was further engineered for optogenetic applications. A single amino-acid substitution that mimicked red-light sensitive rhodopsins like Chrimson shifted the photosensitivity 20 nm towards red light and accelerated photocurrent kinetics. Hence, it was named red and accelerated ACR, raACR. Both wild-type and mutant are capable optical silencers at low light intensities in mouse neurons
in vitro
and
in vivo,
while raACR offers a higher temporal resolution.
Key determinants of the dual clamp/activator function of Complexin
Authors: Makke Mazen , Ruiz Alejandro Pastor , Yarzagaray Antonio , Gaya Surya , Zimmer Michelle , Frisch Walentina , Bruns Dieter
Published: August 2024

Complexin determines magnitude and kinetics of synchronized secretion, but the underlying molecular mechanisms remained unclear. Here, we show that the hydrophobic face of the amphipathic helix at the C-terminus of Complexin II (CpxII, amino acids 115- 134) binds to fusion-promoting SNARE proteins, prevents premature secretion and allows vesicles to accumulate in a release-ready state. Specifically, we demonstrate that an unrelated amphipathic helix functionally substitutes for the CTD of CpxII and that amino acid substitutions on the hydrophobic side compromise the arrest of the prefusion intermediate. To facilitate synchronous vesicle fusion, the N-terminal domain (NTD) of CpxII (amino acids 1-27) specifically cooperates with synaptotagmin I (SytI), but not with synaptotagmin VII. Expression of CpxII rescues the slow release kinetics of the Ca
2+
- binding mutant Syt I R233Q, whereas the N-terminally truncated variant of CpxII further delays it. These results indicate that the CpxII NTD regulates mechanisms which are governed by the forward rate of Ca
2+
binding to Syt I. Overall, our results shed new light on key molecular properties of CpxII that hinder premature exocytosis and accelerate synchronous exocytosis.
Disentangling the relationship between cancer mortality and COVID-19 in the US
Authors: Hansen Chelsea L , Viboud Cécile , Simonsen Lone
Published: August 2024

Cancer is considered a risk factor for COVID-19 mortality, yet several countries have reported that deaths with a primary code of cancer remained within historic levels during the COVID-19 pandemic. Here, we further elucidate the relationship between cancer mortality and COVID-19 on a population level in the US. We compared pandemic-related mortality patterns from underlying and multiple cause (MC) death data for six types of cancer, diabetes, and Alzheimer’s. Any pandemic-related changes in coding practices should be eliminated by study of MC data. Nationally in 2020, MC cancer mortality rose by only 3% over a pre-pandemic baseline, corresponding to ~13,600 excess deaths. Mortality elevation was measurably higher for less deadly cancers (breast, colorectal, and hematological, 2–7%) than cancers with a poor survival rate (lung and pancreatic, 0–1%). In comparison, there was substantial elevation in MC deaths from diabetes (37%) and Alzheimer’s (19%). To understand these differences, we simulated the expected excess mortality for each condition using COVID-19 attack rates, life expectancy, population size, and mean age of individuals living with each condition. We find that the observed mortality differences are primarily explained by differences in life expectancy, with the risk of death from deadly cancers outcompeting the risk of death from COVID-19.
Identification of an early subset of cerebellar nuclei neurons in mice
Authors: Rahimi-Balaei Maryam , Amiri Shayan , Lamonerie Thomas , Wu Sih-Rong , Zoghbi Huda Y , Consalez G Giacomo , Goldowitz Daniel , Marzban Hassan
Published: August 2024

Cerebellar nuclei (CN) neurons serve as the primary output of the cerebellum and originate from the cerebellar primordium at early stages of cerebellar development. Employing various methodologies, we have characterized a specific subset of CN neurons that do not originate from the rhombic lip or ventricular zone of the cerebellar primordium. Embryos were collected at early stages of development and processed for immunohistochemistry (IHC), Western blotting,
in situ
hybridization (ISH), embryonic culture, DiI labeling, and flow cytometry analysis (FCM). Our findings indicate that a subset of CN neurons expressing α-synuclein (SNCA), OTX2, MEIS2, and p75NTR (NGFR) are located in the rostro-ventral (rv) region of the nuclear transitory zone (NTZ), while CN neurons derived from the rhombic lip are positioned in the caudo-dorsal (cd) area of the NTZ in the cerebellar primordium. Utilizing Otx2-GFP and Atoh1
−/−
mice, we have determined that these cells do not originate from the germinal zone of the cerebellar primordium. These results suggest the existence of a novel extrinsic germinal zone for the cerebellar primordium, possibly the mesencephalon, from which early CN neurons originate.
Hosts manipulate lifestyle switch and pathogenicity heterogeneity of opportunistic pathogens in the single-cell resolution
Authors: Wang Ziguang , Li Shuai , Zhang Sheng , Zhang Tianyu , Wu Yujie , Liu Anqi , Wang Kui , Ji Xiaowen , Cao Haiqun , Zhang Yinglao , Tan Eng King , Wang Yongcheng , Wang Yirong , Liu Wei
Published: August 2024

Host-microbe interactions are virtually bidirectional, but how the host affects their microbiome is poorly understood. Here, we report that the host is a critical modulator to regulate the lifestyle switch and pathogenicity heterogeneity of the opportunistic pathogens Serratia marcescens utilizing the Drosophila and bacterium model system. First, we find that Drosophila larvae efficiently outcompete S. marcescens and typically drive a bacterial switch from pathogenicity to commensalism toward the fly. Furthermore, Drosophila larvae reshape the transcriptomic and metabolic profiles of S. marcescens characterized by a lifestyle switch. More importantly, the host alters pathogenicity and heterogeneity of S. marcescens in the single-cell resolution. Finally, we find that larvae-derived AMPs are required to recapitulate the response of S. marcescens to larvae. Altogether, our findings provide an insight into the pivotal roles of the host in harnessing the life history and heterogeneity of symbiotic bacterial cells, advancing knowledge of the reciprocal relationships between the host and pathogen.
Micro-Scale Control of Oligodendrocyte Morphology and Myelination by the Intellectual Disability-Linked Protein Acyltransferase ZDHHC9
Authors: Jeong Hey-Kyeong , Gonzalez-Fernandez Estibaliz , Crawley Ilan , Hwang Jinha , Martin Dale DO , Bamji Shernaz X , Kim Jong-Il , Kang Shin H , Thomas Gareth M
Published: August 2024

Mutations in the X-linked
ZDHHC9
gene cause cognitive deficits in humans, with a subset of patients suffering from epilepsy. X-linked intellectual disability (XLID) is often ascribed to neuronal deficits, but here we report that expression of human and mouse ZDHHC9 orthologs is far higher in myelinating oligodendrocytes (OLs) than in other CNS cell types.
ZDHHC9
codes for a protein acyltransferase (PAT), and we found that ZDHHC9 is the most highly expressed PAT in OLs. Wild type ZDHHC9 localizes to Golgi outposts in OL processes, but other PATs and XLID mutant forms of ZDHHC9 are restricted to OL cell bodies. Using genetic tools for OL progenitor fate tracing and sparse cell labeling, we show that mice lacking
Zdhhc9
have grossly normal OL development but display extensive morphological and structural myelin abnormalities. Consistent with the hypothesis that these deficits are OL-autonomous, they are broadly phenocopied by acute
Zdhhc9
knockdown in cultured conditions. Finally, we found that ZDHHC9 palmitoylates Myelin Basic Protein (MBP) in heterologous cells, and that palmitoylation of MBP is impaired in the
Zdhhc9
knockout brain. Our findings provide critical insights into the mechanisms of
ZDHHC9
-associated XLID and shed new light on the palmitoylation-dependent control of myelination.
Massively Parallel Polyribosome Profiling Reveals Translation Defects of Human Disease-Relevant UTR Mutations
Authors: Li Wei-Ping , Su Jia-Ying , Chang Yu-Chi , Wang Yun-Lin , Chiang Hung-Lun , Hsieh Yu-Tung , Chiang Yi-Hsuan , Ko Yen-Ling , Chiang Bing-Jen , Yang Cheng-Han , Huang Yen-Tsung , Lin Chien-Ling
Published: August 2024

The untranslated regions (UTRs) of mRNAs harbor regulatory elements influencing translation efficiency. Although 3.7% of disease-relevant human mutations occur in UTRs, their exact role in pathogenesis remains unclear. Through metagene analysis, we mapped pathogenic UTR mutations to regions near coding sequences, with a focus on the upstream open reading frame (uORF) initiation site. Subsequently, we utilized massively parallel poly(ribo)some profiling to compare the ribosome associations of 6,555 pairs of wildtype and mutant UTR fragments. We identified 46 UTR variants that altered polysome profiles, with enrichment in pathogenic mutations. Both univariate analysis and the elastic model highlighted the significance of motifs of short repeated sequences, including SRSF2 binding sites, as mutation hotspots that lead to aberrant translation. Furthermore, these polysome-shifting mutations exhibited considerable impact on RNA secondary structures, particularly for upstream AUG-containing 5’ UTRs. Integrating these features, our model achieved high accuracy (AUROC > 0.8) in predicting polysome-shifting mutations in the test dataset. Additionally, several lines of evidence indicate that changes in uORF usage underlie the translation deficiency arising from these mutations. Illustrating this, we demonstrate that a pathogenic mutation in the IRF6 5’ UTR suppresses translation of the primary open reading frame by creating a uORF. Remarkably, site-directed ADAR editing of the mutant mRNA rescued this translation deficiency. Overall, our study provides insights into the molecular mechanisms of UTR mutations and their links to clinical impacts through translation defects.
Neural dynamics of visual working memory representation during sensory distraction
Authors: Degutis Jonas Karolis , Weber Simon , Soch Joram , Haynes John-Dylan
Published: August 2024

Recent studies have provided evidence for the concurrent encoding of sensory percepts and visual working memory contents (VWM) across visual areas; however, it has remained unclear how these two types of representations are concurrently present. Here, we reanalyzed an open-access fMRI dataset where participants memorized a sensory stimulus while simultaneously being presented with sensory distractors. First, we found that the VWM code in several visual regions did not generalize well between different time points, suggesting a dynamic code. A more detailed analysis revealed that this was due to shifts in coding spaces across time. Second, we collapsed neural signals across time to assess the degree of interference between VWM contents and sensory distractors, specifically by testing the alignment of their encoding spaces. We find that VWM and feature-matching sensory distractors are encoded in separable coding spaces. Together, these results indicate a role of dynamic coding and temporally stable coding spaces in helping multiplex perception and VWM within visual areas.
Spatial localization of hippocampal replay requires dopamine signaling
Authors: Kleinman Matthew R , Foster David J
Published: August 2024

Sequenced reactivations of hippocampal neurons called replays, concomitant with sharp-wave ripples in the local field potential, are critical for the consolidation of episodic memory, but whether replays depend on the brain’s reward or novelty signals is unknown. Here we combined chemogenetic silencing of dopamine neurons in ventral tegmental area (VTA) and simultaneous electrophysiological recordings in dorsal hippocampal CA1, in freely behaving rats experiencing changes to reward magnitude and environmental novelty. Surprisingly, VTA silencing did not prevent ripple increases where reward was increased, but caused dramatic, aberrant ripple increases where reward was unchanged. These increases were associated with increased reverse-ordered replays. On familiar tracks this effect disappeared, and ripples tracked reward prediction error, indicating that non-VTA reward signals were sufficient to direct replay. Our results reveal a novel dependence of hippocampal replay on dopamine, and a role for a VTA-independent reward prediction error signal that is reliable only in familiar environments.
An Interesting Case Series of Neuropsychiatric Lupus: A Combination of Inflammatory and Thrombotic Origin
Authors: Kannan Rajkumar , Ganesh Balaji , Thangaraj Abirami , Meleth Rosemin Jose
Published: August 2024

Systemic Lupus Erythematosus (SLE) is a versatile autoimmune disorder with multisystem organ involvement, most commonly involving the skin, joints, vasculature, and associated immunological abnormalities. The hallmark of SLE is the presence of circulating non organ specific humoral autoantibodies synthesised by so-called T cell-dependent B cells, which are germline encoded. Patients with SLE can exhibit symptoms of Central Nervous System (CNS) involvement, termed CNS Lupus, which may also have associated psychiatric manifestations, where the entity gets the designation of Neuropsychiatric SLE (NPSLE). CNS Lupus is often a diagnosis of exclusion, as there are many other aetiological factors that could result in seizures and encephalitis picture. A detailed examination of patients presenting with isolated late-onset seizures is very helpful in uncovering Connective Tissue Disorder (CTD) as the cause of seizures. The manifestations of NPSLE (19 Neuropsychiatric syndromes) can be focal and diffuse, ranging from non specific symptoms such as headache and cognitive impairment to severe manifestations such as memory loss, seizures, stroke, and suicidal intentions. Neuropsychiatric symptoms often occur during the first year of SLE but can rarely also be the presenting symptom of the disease. Antiphospholipid antibodies (Anticardiolipin, Lupus anticoagulant, Anti β2 glycoprotein) and Anti Ribosomal P antibodies are among the frequently associated antibodies in NPSLE, which, in turn, increase the risk of both focal and diffuse neurological complications. A single episode of abortion or miscarriage is a vital clue for a detailed work-up of female patients for the possibility of an underlying occult potential of CNS Lupus in the absence of seizures. The present case series focuses on five female patients who presented with NP symptoms, and finally, the cause was attributed to the involvement of CNS in SLE after excluding other possible organic causes.
Prosthetic Rehabilitation of a Three-year-old Child with Ectodermal Dysplasia: A Case Report
Authors: Shroff Yashshwini , Dutta Brahmananda , Bhuvaneshwari S , Sharma Varsha
Published: August 2024

Ectodermal Dysplasia (ED) is a rare congenital syndrome that exhibits defects in two or more ectodermal tissues. Dental manifestations include delayed eruption of permanent dentition, complete absence of teeth or absence of a few teeth, and peg-shaped teeth. This condition is typically diagnosed by a dentist when parents bring their child with complaints of absent/delayed eruption of primary teeth. Hypohidrotic ED with true anodontia is an extremely rare condition, particularly in females. Over the past 50 years, only 11 cases have been reported involving anodontia of primary and permanent dentition in ED. The current report describes a case of a three-year-old female child diagnosed with hypohidrotic ED with anodontia, successfully treated by fabricating complete dentures with proper retention to restore function and aesthetics.
Zum Abschlussbericht der Expertenkommission „Bürgernahe Einkommensteuer“
Authors: Kanzler Hans-Joachim
Published: August 2024

Der Verf., selbst Mitherausgeber eines Kommentars zum Einkommensteuergesetz, beleuchtet und bewertet den Abschlussbericht der Expertenkommission „Bürgernahe Einkommensteuer“ vom 12.7.2024.
Besteuerung von Earn-out-Vereinbarungen – eine ökonomische Analyse
Authors: Bartsch Gerrit , Höppner Dino
Published: August 2024

Der BFH entschied jüngst, Earn-out-Zahlungen im Rahmen der Veräußerung eines Kommanditgesellschaftsanteils sind in den Zuflussveranlagungszeiträumen zu erfassen (BFH, Urt. v. 9.11.2023 - IV R 9/21). Dabei erging die Entscheidung nur zur gesondert und einheitlichen Feststellung auf Ebene der veräußerten Personengesellschaft (Mitunternehmerschaft). Dieser Beitrag untersucht daher die einkommensteuerrechtlichen Auswirkungen im Rahmen einer materiell-rechtlichen Analyse für natürliche Personen als Veräußerer. Darauf aufbauend erfolgt die Entwicklung und Analyse eines Paritalmodells zur Quantifizierung der einkommensteuerrechtlichen Folgen, wenn durch Vereinbarung einer Earn-out-Komponente die Tarifbegünstigungen nach § 34 EStG in Gänze verloren gehen. Anhand des Modells werden Handlungsempfehlungen an künftige Veräußerer formuliert, unter welchen Bedingungen Earn-out-Vereinbarungen ökonomisch vorteilhaft sind.
Begünstigungsfähige Unternehmer steuerfreier Erziehungs- und Bildungsleistungen
Authors: Esteves Gomes Cristian
Published: August 2024

Das jüngst veröffentlichte Urteil des FG Berlin-Brandenburg vom 17.1.2024 (7 K 7342/16) setzt neue Maßstäbe in Bezug auf begünstigungsfähige Unternehmer steuerfreier Erziehungsleistungen nach Art. 132 Abs. 1 Buchst. i MwStSystRL. Es ist darüber hinaus generell von Bedeutung für die Beurteilung begünstigungsfähiger Unternehmer steuerfreier Bildungsleistungen, sowohl nach aktueller als auch nach der geplanten neuen Rechtslage durch das Jahressteuergesetz (JStG) 2024 zum 1.1.2025. Obgleich noch nicht rechtskräftig, ist diese Entscheidung bereits jetzt aus diesen Gründen bemerkenswert. Ferner ist sie auch in verfahrensrechtlicher Hinsicht ein Musterfall für sehr bedeutende Steuerstreitverfahren zu vermeintlich „kleinen Fällen“. Der Beitrag beleuchtet diese materiell-rechtlichen und verfahrensrechtlichen Facetten.
A minor sudden stratospheric warming with a major impact: Transport and polar processing in the 2014/2015 Arctic winter
Authors: Manney Gloria L. , Lawrence Zachary D. , Santee Michelle L. , Read William G. , Livesey Nathaniel J. , Lambert Alyn , Froidevaux Lucien , Pumphrey Hugh C. , Schwartz Michael J.
Published: September 2015

Stratospheric transport and polar processing during the 2014/2015 Arctic winter were strongly influenced by a minor sudden stratospheric warming (SSW) in early January. Disturbances to temperatures and trace gases in the middle and upper stratosphere were similar in character to those associated with major SSWs: The stratopause dropped, and vertical temperature gradients weakened, followed by renewed descent of mesospheric air. The lower stratospheric polar vortex was barely disrupted and remained unusually strong throughout the winter. The SSW did, however, cause lower stratospheric temperatures to rise well above chlorine activation thresholds; trace gas abundances from the Aura Microwave Limb Sounder (MLS) were consequently exceptional. The degree of chlorine activation in January was the smallest, and lower stratospheric ozone values in February were the highest, in the 11 year MLS record. The major role played by a minor SSW highlights the Arctic stratosphere's sensitivity to a spectrum of dynamical variability.
Asymmetric magnetic reconnection with a flow shear and applications to the magnetopause
Authors: Doss C. E. , Komar C. M. , Cassak P. A. , Wilder F. D. , Eriksson S. , Drake J. F.
Published: September 2015

We perform a systematic theoretical and numerical study of antiparallel two‐dimensional magnetic reconnection with asymmetries in the plasma density and reconnecting magnetic field strength in addition to a bulk flow shear across the reconnection site in the plane of the reconnecting fields, which commonly occurs at planetary magnetospheres. We analytically predict the speed at which an isolated X line is convected by the flow, the reconnection rate, and the critical flow speed at which reconnection no longer takes place for arbitrary reconnecting magnetic field strengths, densities, and upstream flow speeds, and we confirm the results with two‐fluid numerical simulations. The predictions and simulation results counter the prevailing model of reconnection at Earth's dayside magnetopause which says reconnection occurs with a stationary X line for sub‐Alfvénic magnetosheath flow, reconnection occurs but the X line convects for magnetosheath flows between the Alfvén speed and double the Alfvén speed, and reconnection does not occur for magnetosheath flows greater than double the Alfvén speed. In particular, we find that X line motion is governed by momentum conservation from the upstream flows, which are weighted differently in asymmetric systems, so the X line convects for generic conditions including sub‐Alfvénic upstream speeds. For the reconnection rate, as with symmetric reconnection, it drops with increasing flow shear and there is a cutoff speed above which reconnection is not predominant. However, while the cutoff condition for symmetric reconnection is that the difference in flows on the two sides of the reconnection site is twice the Alfvén speed, we find asymmetries cause the cutoff speed for asymmetric reconnection to be higher than twice the asymmetric form of the Alfvén speed. The stronger the asymmetries, the more the cutoff exceeds double the asymmetric Alfvén speed. This is due to the fact that in asymmetric reconnection, the plasma with the smaller mass flux into the dissipation region contributes a smaller mass to the dissipation region, so the effect of its flow on opposing the release of energy by the reconnected magnetic fields is diminished and the reconnection is not suppressed to the extent previously thought. The results compare favorably with an observation of reconnection at Earth's polar cusps during a period of northward interplanetary magnetic field, where reconnection occurs despite the magnetosheath flow speed being more than twice the magnetosheath Alfvén speed, the previously proposed suppression condition. These results are expected to be of broad importance for magnetospheric physics of Earth and other planets; particular applications are discussed.
X lines in the magnetotail for southward and northward IMF conditions
Authors: Zhang L. Q. , Wang J. Y. , Baumjohann W. , Rème H. , Dai L. , Dunlop M. W. , Chen T. , Huang Y.
Published: September 2015

Utilizing associated observations of Geotail and ACE satellites from the year of 1998 to 2005, we investigated the X lines in the near‐Earth tail under different interplanetary magnetic field (IMF) conditions. The X lines are recognized by the tailward fast flows with negative Bz. Statistically, the X lines in the tail can be observed for southward as well as northward IMF, but more frequently observed for southward IMF. A typical case on 26 April 2005 showed clear evidence that the X line can occur for northward IMF while the geomagnetic activity is particularly quiet. Further analysis showed that the X line‐related solar wind has stronger Ey and Bz components for southward than northward IMF. In addition, the X line‐related geomagnetic activities are stronger for southward than northward IMF.
MESSENGER observations of solar energetic electrons within Mercury's magnetosphere
Authors: Gershman Daniel J. , Raines Jim M. , Slavin James A. , Zurbuchen Thomas H. , Anderson Brian J. , Korth Haje , Ho George C. , Boardsen Scott A. , Cassidy Timothy A. , Walsh Brian M. , Solomon Sean C.
Published: September 2015

During solar energetic particle (SEP) events, the inner heliosphere is bathed in MeV electrons. Through magnetic reconnection, these relativistic electrons can enter the magnetosphere of Mercury, nearly instantaneously filling the regions of open field lines with precipitating particles. With energies sufficient to penetrate solid aluminum shielding more than 1 mm thick, these electrons were observable by a number of sensors on the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft. Because of its thin shielding, frequent sampling, and continuous temporal coverage, the Fast Imaging Plasma Spectrometer provided by far the most sensitive measurements of MeV electrons of all MESSENGER sensors. Sharp changes in energetic electron flux coincided with topological boundaries in the magnetosphere, including the magnetopause, polar cap, and central plasma sheet. Precipitating electrons with fluxes equal to ~40% of their corresponding upstream levels were measured over the entire polar cap, demonstrating that electron space weathering of Mercury's surface is not limited to the cusp region. We use these distinct precipitation signatures acquired over 33 orbits during 11 SEP events to map the full extent of Mercury's northern polar cap. We confirm a highly asymmetric polar cap, for which the dayside and nightside boundary latitudes range over ~50–70°N and ~30–60°N, respectively. These latitudinal ranges are consistent with average models of Mercury's magnetic field but exhibit a large variability indicative of active dayside and nightside magnetic reconnection processes. Finally, we observed enhanced electron fluxes within the central plasma sheet. Although these particles cannot form a stable ring current around the planet, their motion results in an apparent trapped electron population at low latitudes in the magnetotail.
On the evolution of a magnetic flux rope: Two‐dimensional MHD simulation results
Authors: Teh W.‐L. , Nakamura T. K. M. , Nakamura R. , Baumjohann W. , Abdullah M.
Published: September 2015

We use the time‐dependent, two‐dimensional (2‐D), ideal MHD equations to simulate and investigate the evolution of magnetic field and plasma profiles of the typical (T) and crater (C) magnetic flux ropes (FRs). The T‐FR has a magnetic pressure peak at the center of the flux rope, while the C‐FR has a local dip instead. The simulation starts with a 2‐D magnetic flux rope in magnetohydrostatic equilibrium, where pressure gradient forces are balanced by Lorentz forces. The magnetic field and plasma pressure profiles for the initial flux rope are derived from the analytical solutions by Zhang et al. (2010). The initial flux rope starts to evolve when the force balance is broken by imposing pressure or magnetic field perturbations onto the equilibrium system. The pressure perturbations are produced by increasing/decreasing the internal plasma pressure of the flux rope, while the magnetic field perturbations are produced by increasing/decreasing the transverse magnetic fields across the flux rope. We conclude that a T‐FR can be evolved into a C‐FR and vice versa, if the perturbation strength is sufficient, and that the plasma pressure and density in the new equilibrium state could be either increased or decreased for the evolution of C‐FR to T‐FR and also for the evolution of T‐FR to C‐FR.
Principal components of quiet time temporal variability of equatorial and low‐latitude geomagnetic fields
Authors: Bhattacharyya Archana , Okpala Kingsley C.
Published: September 2015

Diurnal variations of the horizontal component of the geomagnetic field ΔH on International Quiet days of 1999–2012, measured hourly at two stations in the same longitude zone in the Northern Hemisphere, near and away from the dip equator, have been subjected to principal component analysis. This technique is also applied to the difference ΔHEEJ of ΔH at these two stations, which is attributed to the equatorial electrojet (EEJ). The first three principal components, PC1–PC3, account for 91–96% of the variances in the data. Maximum contribution to the quiet day variations in ΔH around its peak in the morning hours at both the stations, and in the EEJ, comes from the day‐to‐day variation of the amplitude of PC1. Patterns of day‐to‐day variations of PC1 amplitudes for the equatorial station and the EEJ are essentially semiannual modulated by solar EUV flux, superimposed on a longer timescale solar EUV flux‐dependent trend. Contributions from PC2 and to a lesser extent from PC3 are seen to be responsible for the absence of semiannual variations in ΔH in the afternoon hours at the equatorial station. Distribution of amplitudes of PC2 and PC3 for ΔHEEJ for weak electrojet days shows seasonal features in accordance with greater occurrence of afternoon (morning) counter electrojet during June (December) solstice. During the extended solar minimum, PC3 amplitudes for ΔH at the equatorial station and for the EEJ display annual variation. Possible sources for these seasonal features in the variations of equatorial ΔH are discussed.
Multispacecraft current estimates at swarm
Authors: Dunlop M. W. , Yang Y.‐Y. , Yang J.‐Y. , Lühr H. , Shen C. , Olsen N. , Ritter P. , Zhang Q.‐H. , Cao J.‐B. , Fu H.‐S. , Haagmans R.
Published: September 2015

During the first several months of the three‐spacecraft Swarm mission all three spacecraft came repeatedly into close alignment, providing an ideal opportunity for validating the proposed dual‐spacecraft method for estimating current density from the Swarm magnetic field data. Two of the Swarm spacecraft regularly fly side‐by‐side in closely similar orbits, while the third at times approaches the other two. This provides a data set which under certain assumptions of stationarity of the magnetic field can produce 2, 3, 4, 5 (or more) point measurements, which can be cross compared. We find that at low Earth orbit the use of time‐shifted positions allow stable estimates of current density to be made and can verify temporal effects as well as validating the interpretation of the current components as arising predominantly from field‐aligned currents. In the case of four‐spacecraft configurations we can resolve the full vector current and therefore can check the perpendicular as well as parallel current density components directly, together with the quality factor for the estimates directly (for the first time in situ at low Earth orbit).
The role of passive margins on the evolution of Subduction‐Transform Edge Propagators (STEPs)
Authors: Nijholt Nicolai , Govers Rob
Published: September 2015

A Subduction‐Transform Edge Propagator (STEP) is the locus of continual lithospheric tearing which enables subduction of one part of a tectonic plate, while the juxtaposed part remains at the surface. A key question is the propagation direction of active STEPs, and we suspect passive margins to play a critical role in steering STEPs. We investigate the role of passive margins (width, orientation, and lateral strength contrast) on the STEP propagation direction through mechanical finite element models. For straight passive margins, we show that STEPs remain parallel to passive margins when within 15° from a trench‐perpendicular geometry. In other cases, where passive margins change strike ahead of the active STEP, STEPs are captured by passive margins for abrupt strike changes (radius of curvature < lithosphere thickness) less than 25° from trench perpendicular. Outside this window, STEPs will propagate in the original direction. If a strike change (>25°) is made through a large radius of curvature (>lithosphere thickness), STEPs will also propagate along the passive margin. A STEP system evolves toward orthogonality, which may explain why STEP faults are approximately perpendicular to trenches in nature. STEP systems are relatively insensitive to small‐scale details (due to large‐scale stresses), propagating as straight features along rugged passive margins. Surprisingly, magnitudes of lithospheric strength variation across the passive margin and subduction history, which determines location and magnitude of density anomalies in the mantle, are less relevant for the STEP propagation direction.
Measuring black carbon spectral extinction in the visible and infrared
Authors: Smith A. J. A. , Peters D. M. , McPheat R. , Lukanihins S. , Grainger R. G.
Published: September 2015

This work presents measurements of the spectral extinction of black carbon aerosol from 400 nm to 15 μm. The aerosol was generated using a Miniature Combustion Aerosol Standard soot generator and then allowed to circulate in an aerosol cell where its extinction was measured using a grating spectrometer in the visible and a Fourier transform spectrometer in the infrared. Size distribution, number concentration, and mass extinction cross sections have also been obtained using single‐particle aerosol samplers. A mean mass extinction cross section at 550 nm of 8.3 ± 1.6 m2 g−1 is found which, assuming a reasonable single scatter albedo of 0.2, corresponds to a mass absorption cross section of 6.6 ± 1.3 m2 g−1. This compares well with previously reported literature values. Computer analysis of electron microscope images of the particles provides independent confirmation of the size distribution as well as fractal parameters of the black carbon aerosol. The aerosol properties presented in this work are representative of very fresh, uncoated black carbon aerosol. After atmospheric processing of such aerosols (which could include mixing with other constituents and structural changes), different optical properties would be expected.
Effects of debris flow composition on runout, depositional mechanisms, and deposit morphology in laboratory experiments
Authors: de Haas Tjalling , Braat Lisanne , Leuven Jasper R. F. W. , Lokhorst Ivar R. , Kleinhans Maarten G.
Published: September 2015

Predicting debris flow runout is of major importance for hazard mitigation. Apart from topography and volume, runout distance and area depends on debris flow composition and rheology, but how is poorly understood. We experimentally investigated effects of composition on debris flow runout, depositional mechanisms, and deposit geometry. The small‐scale experimental debris flows were largely similar to natural debris flows in terms of flow behavior, deposit morphology, grain size sorting, channel width‐depth ratio, and runout. Deposit geometry (lobe thickness and width) in our experimental debris flows is largely determined by composition, while the effects of initial conditions of topography (i.e., outflow plain slope and channel slope and width) and volume are negligible. We find a clear optimum in the relations of runout with coarse‐material fraction and clay fraction. Increasing coarse‐material concentration leads to larger runout. However, excess coarse material results in a large accumulation of coarse debris at the flow front and enhances diffusivity, increasing frontal friction and decreasing runout. Increasing clay content initially enhances runout, but too much clay leads to very viscous flows, reducing runout. Runout increases with channel slope and width, outflow plain slope, debris flow volume, and water fraction. These results imply that debris flow runout depends at least as much on composition as on topography. This study improves understanding of the effects of debris flow composition on runout and may aid future debris flow hazard assessments.
Marsh‐atmosphere CO2 exchange in a New England salt marsh
Authors: Forbrich Inke , Giblin Anne E.
Published: September 2015

We studied marsh‐atmosphere exchange of carbon dioxide in a high marsh dominated salt marsh during the months of May to October in 2012–2014. Tidal inundation at the site occurred only during biweekly spring tides, during which we observed a reduction in fluxes during day and night. We estimated net ecosystem exchange (NEE), gross primary production (GPP), and ecosystem respiration (Reco) using a modified PLIRTLE model, which requires photosynthetically active radiation, temperature, and normalized difference vegetation index (NDVI) as control variables. NDVI decreased during inundation, when the marsh canopy was submerged. Two‐time series of NDVI, including and excluding effects of tidal inundation, allowed us to quantify the flux reduction during inundation. The effect of the flux reduction was small (2–4%) at our site, but is likely higher for marshes at a lower elevation. From May to October, GPP averaged −863 g C m−2, Reco averaged 591 g C m−2, and NEE averaged −291 g C m−2. In 2012, which was an exceptionally warm year, we observed an early start of net carbon uptake but higher respiration than in 2013 and 2014 due to higher‐air temperature in August. This resulted in the lowest NEE during the study period (−255.9±6.9 g C m−2). The highest seasonal net uptake (−336.5±6.3 g C m−2) was observed in 2013, which was linked to higher rainfall and temperature in July. Mean sea level was very similar during all 3 years which allowed us to isolate the importance of climatic factors.
Ensemble Modeling of the 23 July 2012 Coronal Mass Ejection
Authors: Cash M. D. , Biesecker D. A. , Pizzo V. , de Koning C. A. , Millward G. , Arge C. N. , Henney C. J. , Odstrcil D.
Published: September 2015

On 23 July 2012 a significant and rapid coronal mass ejection (CME) was detected in situ by the Solar Terrestrial Relations Observatory (STEREO) A. This CME was unusual due to its extremely brief Sun‐to‐1 AU transit time of less than 21 h and its exceptionally high impact speed of 2246 km/s. If this CME had been Earth directed, it would have produced a significant geomagnetic storm with potentially serious consequences. To protect our ground‐ and space‐based assets, there is a clear need to accurately forecast the arrival times of such events using realistic input parameters and models run in near real time. Using Wang‐Sheely‐Arge (WSA)‐Enlil, the operational model currently employed at the NOAA Space Weather Prediction Center, we investigate the sensitivity of the 23 July CME event to model input parameters. Variations in the initial CME speed, angular width, and direction, as well as the ambient solar wind background, are investigated using an ensemble approach to study the effect on the predicted arrival time of the CME at STEREO A. Factors involved in the fast transit time of this large CME are discussed, and potential improvements to modeling such events with the WSA‐Enlil model are presented.