julilili42/papers huggingface dataset:
Mathematics anxiety reduces default mode network deactivation in response to numerical tasks
2015-04-21

Mathematics anxiety is negatively related to mathematics performance, thereby threatening the professional success. Preoccupation with the emotional content of the stimuli may consume working memory resources, which may be reflected in decreased deactivation of areas associated with the default mode network (DMN) activated during self-referential and emotional processing. The common problem is that math anxiety is usually associated with poor math performance, so that any group differences are difficult to interpret. Here we compared the BOLD-response of 18 participants with high (HMAs) and 18 participants with low mathematics anxiety (LMAs) matched for their mathematical performance to two numerical tasks (number comparison, number bisection). During both tasks, we found stronger deactivation within the DMN in LMAs compared to HMAs, while BOLD-response in task-related activation areas did not differ between HMAs and LMAs. The difference in DMN deactivation between the HMA and LMA group was more pronounced in stimuli with additional requirement on inhibitory functions, but did not differ between number magnitude processing and arithmetic fact retrieval.
Spatiotemporal variability of modern precipitation δ18O in the central Andes and implications for paleoclimate and paleoaltimetry estimates
2015-04-21

Abstract Understanding the patterns of rainfall isotopic composition in the central Andes is hindered by sparse observations. Despite limited observational data, stable isotope tracers have been commonly used to constrain modern‐to‐ancient Andean atmospheric processes, as well as to reconstruct paleoclimate and paleoaltimetry histories. Here, we present isotopic compositions of precipitation ( δ 18 O p and δ D p ) from 11 micrometeorological stations located throughout the Bolivian Altiplano and along its eastern flank at ~21.5°S. We collected and isotopically analyzed 293 monthly bulk precipitation samples (August 2008 to April 2013). δ 18 O p values ranged from −28.0‰ to 9.6‰, with prominent seasonal cycles expressed at all stations. We observed a strong relationship between the δ 18 O p and elevation, though it varies widely in time and space. Constraints on air sourcing estimated from atmospheric back trajectory calculations indicate that continental‐scale climate dynamics control the interannual variability in δ 18 O p , with upwind precipitation anomalies having the largest effect. The impact of precipitation anomalies in distant air source regions to the central Andes is in turn modulated by the Bolivian High. The importance of the Bolivian High is most clearly observed on the southern Bolivian Altiplano. However, monthly variability among Altiplano stations can exceed 10‰ in δ 18 O p on the plateau and cannot be explained by elevation or source variability, indicating a nontrivial role for local scale effects on short timescales. The strong influence of atmospheric circulation on central Andean δ 18 O p requires that paleoclimate and paleoaltimetry studies consider the role of South American atmospheric paleocirculation in their interpretation of stable isotopic values as proxies.
Tuning the Terahertz Emission Power of an Intrinsic Josephson-Junction Stack with a Focused Laser Beam
2015-04-21

Developing a tunable source of high-power terahertz radiation is an ongoing research challenge, with promise for applications including biosensing and high-speed communication. The authors show that the THz emission from a stack of intrinsic Josephson junctions in a cuprate superconductor embedded between two gold layers can be manipulated by a focused laser beam. The output power can be increased by as much as 75% with laser irradiation, and tuned continuously and rapidly as the laser beam is moved along the length of the stack, locally heating different spots of the sample.
On the structure of population activity under fluctuations in attentional state
2015-04-21

Attention is commonly thought to improve behavioral performance by increasing response gain and suppressing shared variability in neuronal populations. However, both the focus and the strength of attention are likely to vary from one experimental trial to the next, thereby inducing response variability unknown to the experimenter. Here we study analytically how fluctuations in attentional state affect the structure of population responses in a simple model of spatial and feature attention. In our model, attention acts on the neural response exclusively by modulating each neuron's gain. Neurons are conditionally independent given the stimulus and the attentional gain, and correlated activity arises only from trial-to-trial fluctuations of the attentional state, which are unknown to the experimenter. We find that this simple model can readily explain many aspects of neural response modulation under attention, such as increased response gain, reduced individual and shared variability, increased correlations with firing rates, limited range correlations, and differential correlations. We therefore suggest that attention may act primarily by increasing response gain of individual neurons without affecting their correlation structure. The experimentally observed reduction in correlations may instead result from reduced variability of the attentional gain when a stimulus is attended. Moreover, we show that attentional gain fluctuations – even if unknown to a downstream readout – do not impair the readout accuracy despite inducing limited-range correlations.
Bounds for the Quantifier Depth in Finite-Variable Logics
2015-04-21

Given two structures G and H distinguishable in FO k (first-order logic with k variables), let A k ( G , H ) denote the minimum alternation depth of a FO k formula distinguishing G from H . Let A k ( n ) be the maximum value of A k ( G , H ) over n -element structures. We prove the strictness of the quantifier alternation hierarchy of FO 2 in a strong quantitative form, namely A 2 ( n ) &gt; n /8 − 2, which is tight up to a constant factor. For each k ⩾ 2, it holds that A k ( n ) &gt; log k + 1 n − 2 even over colored trees, which is also tight up to a constant factor if k ⩾ 3. For k ⩾ 3, the last lower bound holds also over uncolored trees, whereas the alternation hierarchy of FO 2 collapses even over all uncolored graphs. We also show examples of colored graphs G and H on n vertices that can be distinguished in FO 2 much more succinctly if the alternation number is increased just by one: Whereas in Σ i it is possible to distinguish G from H with bounded quantifier depth, in Π i this requires quantifier depth Ω( n 2 ). The quadratic lower bound is best possible here because, if G and H can be distinguished in FO k with i quantifier alternations, this can be done with quantifier depth n 2 k − 2 + 1 and the same number of alternations.
Cooperative action of the paralogous maize lateral organ boundaries (LOB) domain proteins RTCS and RTCL in shoot‐borne root formation
2015-04-22

Summary The paralogous maize ( Zea mays ) LBD ( Lateral Organ Boundaries Domain ) genes rtcs ( rootless concerning crown and seminal roots ) and rtcl ( rtcs‐like ) emerged from an ancient whole‐genome duplication. RTCS is a key regulator of crown root initiation. The diversity of expression, molecular interaction and phenotype of rtcs and rtcl were investigated. The rtcs and rtcl genes display highly correlated spatio‐temporal expression patterns in roots, despite the significantly higher expression of rtcs . Both RTCS and RTCL proteins bind to LBD downstream promoters and act as transcription factors. In line with its auxin inducibility and binding to auxin response elements of rtcs and rtcl promoters, ARF 34 ( AUXIN RESPONSE FACTOR 34) acts as transcriptional activator. Yeast two‐hybrid screening combined with bimolecular fluorescence complementation (Bi FC ) experiments revealed conserved and unique interaction partners of RTCS and RTCL . The rtcl mutation leads to defective shoot‐borne root elongation early in development. Cooperative action of RTCS and RTCL during shoot‐borne root formation was demonstrated by rtcs ‐dependent repression of rtcl transcription in coleoptilar nodes. Although RTCS is instrumental in shoot‐borne root initiation, RTCL controls shoot‐borne root elongation early in development. Their conserved role in auxin signaling, but diverse function in shoot‐borne root formation, is underscored by their conserved and unique interaction partners.
β-Blockers, Pneumonia, and Outcome After Ischemic Stroke
2015-04-22

Background and Purpose— Increased sympathetic drive after stroke is involved in the pathophysiology of several complications including poststroke immunudepression. β-Blocker (BB) therapy has been suggested to have neuroprotective properties and to decrease infectious complications after stroke. We aimed to examine the effects of random pre- and on-stroke BB exposure on mortality, functional outcome, and occurrence of pneumonia after ischemic stroke. Methods— Data including standard demographic and clinical variables as well as prestroke and on-stroke antihypertensive medication, incidence of pneumonia, functional outcome defined using modified Rankin Scale and mortality at 3 months were extracted from the Virtual International Stroke Trials Archive. For statistical analysis multivariable Poisson regression was used. Results— In total, 5212 patients were analyzed. A total of 1155 (22.2%) patients were treated with BB before stroke onset and 244 (4.7%) patients were newly started with BB in the acute phase of stroke. Mortality was 17.5%, favorable outcome (defined as modified Rankin Scale, 0–2) occurred in 58.2% and pneumonia in 8.2% of patients. Prestroke BB showed no association with mortality. On-stroke BB was associated with reduced mortality (adjusted risk ratio, 0.63; 95% confidence interval, 0.42–0.96). Neither prestroke BB nor on-stroke BB showed an association with functional outcome. Both prestroke and on-stroke BB were associated with reduced frequency of pneumonia (adjusted risk ratio, 0.77; 95% confidence interval, 0.6–0.98 and risk ratio, 0.49; 95% confidence interval, 0.25–0.95). Conclusions— In this large nonrandomized comparison, on-stroke BB was associated with reduced mortality. Prestroke and on-stroke BB were inversely associated with incidence of nosocomial pneumonia. Randomized trials investigating the potential of β-blockade in acute stroke may be warranted.
A Comparative pO2 Probe and [18F]-Fluoro-Azomycinarabino-Furanoside ([18F]FAZA) PET Study Reveals Anesthesia-Induced Impairment of Oxygenation and Perfusion in Tumor and Muscle
2015-04-22

[18F]FAZA tumor uptake was highest in ketamine/xylazine-anesthetized mice regardless of whether the mice breathed air or oxygen. The generally lower [18F]FAZA whole-body uptake in isoflurane-anesthetized mice could be due to the higher muscle pO2-values in these mice compared to ketamine/xylazine-anesthetized mice. When performing preclinical in vivo hypoxia PET studies, oxygen should be avoided, and ketamine/xylazine-anesthesia might alleviate the identification of tumor hypoxia areals.
In Europe expression of EBNA2 is associated with poor survival in EBV-positive diffuse large B-cell lymphoma of the elderly
2015-04-22

Epstein-Barr virus (EBV)-positive diffuse large B-cell lymphoma (DLBCL) of the elderly occurs by definition in patients above the age of 50 years without any known underlying immunodeficiency. We investigated the incidence and clinical relevance of this subtype in Europe with special attention to the EBV-latency type. Among the 598 DLBCL, 15 EBV-positive lymphomas fulfilling the criteria of EBV-positive DLBCL of the elderly were identified (2.5%). Patients with EBV-positive DLBCL expressing EBNA2 showed a significantly poorer overall survival than patients with EBNA2-negative EBV-positive DLBCL (p = 0.0156). The incidence of EBV-positive DLBCL of the elderly in Europe is much lower than in Asian countries (2.5% of all cases of DLBCL). Interestingly, the likelihood of EBV positivity did not increase with age in patient above 50 years. Among EBV-positive DLBCL of the elderly a subgroup with EBV-latency type III expressing EBNA2 can be identified, which shows a poor outcome.
Evaluation of A New Bolus Tracking–Based Algorithm for Predicting A Patient-Specific Time of Arterial Peak Enhancement in Computed Tomography Angiography
2015-04-22

The new algorithm can robustly predict a patient-specific time of arterial peak enhancement and is better than a best-case scenario for the current bolus tracking technique because interpatient variations are taken into account. It offers a new framework for scan timing optimization and can potentially be used for personalized scan timing in real time.
LATERAL ROOT PRIMORDIA 1 of maize acts as a transcriptional activator in auxin signalling downstream of the Aux/IAA gene rootless with undetectable meristem 1
2015-04-23

Only little is known about target genes of auxin signalling downstream of the Aux/IAA-ARF module. In the present study, it has been demonstrated that maize lateral root primordia 1 (lrp1) encodes a transcriptional activator that is directly regulated by the Aux/IAA protein ROOTLESS WITH UNDETECTABLE MERISTEM 1 (RUM1). Expression of lrp1 is confined to early root primordia and meristems and is auxin-inducible. Based on its primary protein structure, LRP1 is predicted to be a transcription factor. This notion is supported by exclusive LRP1 localization in the nucleus and its ability to activate downstream gene activity. Based on the observation that lrp1 transcription is completely repressed in the semi-dominant gain of function mutant rum1, it was demonstrated that the lrp1 promoter is a direct target of RUM1 proteins. Subsequently, promoter activation assays indicated that RUM1 represses the expression of a GFP reporter fused to the native promoter of lrp1. Constitutive repression of lrp1 in rum1 mutants is a consequence of the stability of mutated rum1 proteins which cannot be degraded by the proteasome and thus constitutively bind to the lrp1 promoter and repress transcription. Taken together, the repression of the transcriptional activator lrp1 by direct binding of RUM1 to its promoter, together with specific expression of lrp1 in root meristems, suggests a function in maize root development via the RUM1-dependent auxin signalling pathway.
Enhanced Eryptosis Following Gramicidin Exposure
2015-04-23

The peptide antibiotic and ionophore gramicidin has previously been shown to trigger apoptosis of nucleated cells. In analogy to apoptosis, the suicidal death of erythrocytes or eryptosis involves cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Triggers of eryptosis include oxidative stress, increase of cytosolic Ca2+ activity ([Ca2+]i), and ceramide. The present study explored, whether gramicidin triggers eryptosis. To this end phosphatidylserine exposure at the cell surface was estimated from annexin V binding, cell volume from forward scatter, red blood cell distribution width (RDW) from electronic particle counting, reactive oxidant species (ROS) from 2',7'-dichlorodihydrofluorescein diacetate (DCFDA) fluorescence, [Ca2+]i from Fluo3- and Fluo4 fluorescence, and ceramide abundance from binding of specific antibodies. As a result, a 24 h exposure of human erythrocytes to gramicidin significantly increased the percentage of annexin-V-binding cells (≥1 μg/mL), forward scatter (≥0.5 μg/mL) and hemolysis. Gramicidin enhanced ROS activity, [Ca2+]i and ceramide abundance at the erythrocyte surface. The stimulation of annexin-V-binding by gramicidin was significantly blunted but not abolished by removal of extracellular Ca2+. In conclusion, gramicidin stimulates phospholipid scrambling of the erythrocyte cell membrane, an effect at least partially due to induction of oxidative stress, increase of [Ca2+]i and up-regulation of ceramide abundance. Despite increase of [Ca2+]i, gramicidin increases cell volume and slightly reduces RWD.
Utility of characteristic ‘Weak to Absent’ INI1/SMARCB1/BAF47 expression in diagnosis of synovial sarcomas
2015-04-24

Recently, very few studies have shown value of immunohistochemical ( IHC ) expression of INI 1/ SMARCB 1 in diagnosis of synovial sarcomas ( SS s). This study was aimed at testing reproducibility and utility of this finding. Sixty‐eight SS s and 147 other tumours, in the form of various biopsies, were tested for IHC expression of INI 1. Twenty‐six SS s were further confirmed with positive SS 18 rearrangement. Forty monophasic spindle cell type (58.8%), 13 biphasic (19.1%), 12 poorly differentiated (17.6%) and three calcifying SS s (4.4%) were positive for epithelial membrane antigen ( EMA ) (46/62) (74.1%), pan cytokeratin ( AE 1/ AE 3) (31/47) (65.9%), cytokeratin ( CK 7) (20/31) (64.5%), BCL 2 (62/66) (93.9%), MIC 2 (61/63) (96.8%), transducin‐like enhancer of split 1 ( TLE 1) (29/31) (93.5%) and CK 19 (14/24) (58.3%). INI 1 expression was ‘weak to absent’ in 60/68 (88.2%) SS s; in 1/3 atypical ossifying fibromyxoid tumours ( AOFMT s) and in 3/10 (30%) malignant peripheral nerve sheath tumours ( MPNST s) of various types. INI 1 was completely absent in 10/10 (100%) epithelioid sarcomas ( ES s), 4/4 (100%) malignant rhabdoid tumours, single paediatric undifferentiated sarcoma, 5/19 (26.3%) myoepithelial carcinomas and in 2/4 (50%) epithelioid‐subtype of MPNST s. Remaining 100 tumours, including 12 E wing sarcomas, 15 carcinomas, eight solitary fibrous tumours ( SFT ), seven extraskeletal myxoid chondrosarcomas, three fibrosarcomas and other tumours retained INI 1 expression. A unique ‘weak to absent’ IHC expression of INI 1 is highly sensitive (88.2%) and specific (97.3%) for a SS , irrespective of its subtypes and types of biopsies. This can be considered useful in diagnosing SS s, especially in settings lacking molecular and/or cytogenetic analysis. A similar INI 1 expression is shared by certain AOFMT s and MPNST s.
The cross-linguistic processing of aspect – an eyetracking study on the time course of aspectual interpretation in Russian and German
2015-04-24

This paper reports a cross-linguistic study on the time course of aspectual interpretation in an aspect language (Russian) and a non-aspect language (German). In Russian, mereological semantics led us to expect incremental mismatch detection independently of the presence or absence of the verbal arguments. In German, however, mismatch effects should be delayed until the processor has encountered the complete predication. These predictions were tested in two eyetracking during reading experiments. We investigated the processing of achievement verbs modified by aspectually mismatching adverbials in Russian (Exp. 1) and German (Exp. 2) and manipulated the word order in such a way that the mismatch occurred before or after the predication was complete. The data show that Russian readers immediately noticed the mismatch independently of whether the verb preceded or followed its arguments, whereas German readers showed mismatch effects only after a complete predication. We take this as evidence for cross-linguistically different increment sizes in event interpretation.
Role of Small RNAs in Regulation of Plant Responses to Stress
2015-04-24

Small RNAs (sRNAs) comprise a large class of non-coding RNAs (ncRNAs), which act as important regulators of gene expression at both transcriptional and post-transcriptional levels. In plants, sRNAs can be divided into different classes depending on their size, origin, processing, and function. In a nutshell, sRNAs can be subgrouped into two categories: small interfering RNAs (siRNAs) and microRNAs (miRNAs). This chapter briefly introduces the different kinds of sRNAs and their modes of action. It provides a selection of fascinating examples of how different classes of sRNAs contribute to plant resistance to both biotic and abiotic stress conditions. miRNAs have two main modes of action: target RNA cleavage or mRNA translational repression. The chapter reviews the important roles of sRNAs in diverse stress situations, starting with sRNA function in response to biotic stress.
Photoautotrophic Polyhydroxybutyrate Granule Formation Is Regulated by Cyanobacterial Phasin PhaP in Synechocystis sp. Strain PCC 6803
2015-04-25

ABSTRACT Cyanobacteria are photoautotrophic microorganisms which fix atmospheric carbon dioxide via the Calvin-Benson cycle to produce carbon backbones for primary metabolism. Fixed carbon can also be stored as intracellular glycogen, and in some cyanobacterial species like Synechocystis sp. strain PCC 6803, polyhydroxybutyrate (PHB) accumulates when major nutrients like phosphorus or nitrogen are absent. So far only three enzymes which participate in PHB metabolism have been identified in this organism, namely, PhaA, PhaB, and the heterodimeric PHB synthase PhaEC. In this work, we describe the cyanobacterial PHA surface-coating protein (phasin), which we term PhaP, encoded by ssl2501 . Translational fusion of Ssl2501 with enhanced green fluorescent protein (eGFP) showed a clear colocalization to PHB granules. A deletion of ssl2501 reduced the number of PHB granules per cell, whereas the mean PHB granule size increased as expected for a typical phasin. Although deletion of ssl2501 had almost no effect on the amount of PHB, the biosynthetic activity of PHB synthase was negatively affected. Secondary-structure prediction and circular dichroism (CD) spectroscopy of PhaP revealed that the protein consists of two α-helices, both of them associating with PHB granules. Purified PhaP forms oligomeric structures in solution, and both α-helices of PhaP contribute to oligomerization. Together, these results support the idea that Ssl2501 encodes a cyanobacterial phasin, PhaP, which regulates the surface-to-volume ratio of PHB granules.
Spatial and temporal variation of body size among early Homo
2015-04-26

The estimation of body size among the earliest members of the genus Homo (2.4-1.5Myr [millions of years ago]) is central to interpretations of their biology. It is widely accepted that Homo ergaster possessed increased body size compared with Homo habilis and Homo rudolfensis, and that this may have been a factor involved with the dispersal of Homo out of Africa. The study of taxonomic differences in body size, however, is problematic. Postcranial remains are rarely associated with craniodental fossils, and taxonomic attributions frequently rest upon the size of skeletal elements. Previous body size estimates have been based upon well-preserved specimens with a more reliable species assessment. Since these samples are small (n < 5) and disparate in space and time, little is known about geographical and chronological variation in body size within early Homo. We investigate temporal and spatial variation in body size among fossils of early Homo using a 'taxon-free' approach, considering evidence for size variation from isolated and fragmentary postcranial remains (n = 39). To render the size of disparate fossil elements comparable, we derived new regression equations for common parameters of body size from a globally representative sample of hunter-gatherers and applied them to available postcranial measurements from the fossils. The results demonstrate chronological and spatial variation but no simple temporal or geographical trends for the evolution of body size among early Homo. Pronounced body size increases within Africa take place only after hominin populations were established at Dmanisi, suggesting that migrations into Eurasia were not contingent on larger body sizes. The primary evidence for these marked changes among early Homo is based upon material from Koobi Fora after 1.7Myr, indicating regional size variation. The significant body size differences between specimens from Koobi Fora and Olduvai support the cranial evidence for at least two co-existing morphotypes in the Early Pleistocene of eastern Africa.