bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ergodic and localized regions in quantum spin glasses on the Bethe lattice
Authors: Mossi G. , Scardicchio A. 
Published: October 2017

By considering the quantum dynamics of a transverse-field Ising spin glass on the Bethe lattice, we find the existence of a many-body localized (MBL) region at small transverse field and low temperature. The region is located within the thermodynamic spin glass phase. Accordingly, we conjecture that quantum dynamics inside the glassy region is split into a small MBL region and a large delocalized (but not necessarily ergodic) region. This has implications for the analysis of the performance of quantum adiabatic algorithms.
This article is part of the themed issue ‘Breakdown of ergodicity in quantum systems: from solids to synthetic matter’.
A perspective on quantum integrability in many-body-localized and Yang–Baxter systems
Authors: Moore Joel E. 
Published: October 2017

Two of the most active areas in quantum many-particle dynamics involve systems with an unusually large number of conservation laws. Many-body-localized systems generalize ideas of Anderson localization by disorder to interacting systems. While localization still exists with interactions and inhibits thermalization, the interactions between conserved quantities lead to some dramatic differences from the Anderson case. Quantum integrable models such as the XXZ spin chain or Bose gas with delta-function interactions also have infinite sets of conservation laws, again leading to modifications of conventional thermalization. A practical way to treat the hydrodynamic evolution from local equilibrium to global equilibrium in such models is discussed. This paper expands upon a presentation at a discussion meeting of the Royal Society on 7 February 2017. The work described was carried out with a number of collaborators, including Jens Bardarson, Vir Bulchandani, Roni Ilan, Christoph Karrasch, Siddharth Parameswaran, Frank Pollmann and Romain Vasseur.
This article is part of the themed issue ‘Breakdown of ergodicity in quantum systems: from solids to synthetic matter’.
Dynamical manifestations of quantum chaos: correlation hole and bulge
Authors: Torres-Herrera E. J. , Santos Lea F. 
Published: October 2017

A main feature of a chaotic quantum system is a rigid spectrum where the levels do not cross. We discuss how the presence of level repulsion in lattice many-body quantum systems can be detected from the analysis of their time evolution instead of their energy spectra. This approach is advantageous to experiments that deal with dynamics, but have limited or no direct access to spectroscopy. Dynamical manifestations of avoided crossings occur at long times. They correspond to a drop, referred to as correlation hole, below the asymptotic value of the survival probability and to a bulge above the saturation point of the von Neumann entanglement entropy and the Shannon information entropy. By contrast, the evolution of these quantities at shorter times reflects the level of delocalization of the initial state, but not necessarily a rigid spectrum. The correlation hole is a general indicator of the integrable–chaos transition in disordered and clean models and as such can be used to detect the transition to the many-body localized phase in disordered interacting systems.
This article is part of the themed issue ‘Breakdown of ergodicity in quantum systems: from solids to synthetic matter’.
Evolutionary dynamics of bacteria in the gut microbiome within and across hosts
Authors: Garud Nandita R. , Good Benjamin H. , Hallatschek Oskar , Pollard Katherine S. 
Published: October 2017

AbstractGut microbiota are shaped by a combination of ecological and evolutionary forces. While the ecological dynamics have been extensively studied, much less is known about how species of gut bacteria evolve over time. Here we introduce a model-based framework for quantifying evolutionary dynamics within and across hosts using a panel of metagenomic samples. We use this approach to study evolution in ∼30 prevalent species in the human gut. Although the patterns of between-host diversity are consistent with quasi-sexual evolution and purifying selection on long timescales, we identify new genealogical signatures that challenge standard population genetic models of these processes. Within hosts, we find that genetic differences that accumulate over ∼6 month timescales are only rarely attributable to replacement by distantly related strains. Instead, the resident strains more commonly acquire a smaller number of putative evolutionary changes, in which nucleotide variants or gene gains or losses rapidly sweep to high frequency. By comparing these mutations with the typical between-host differences, we find evidence that some sweeps are seeded by recombination, in addition to new mutations. However, comparisons of adult twins suggest that replacement eventually overwhelms evolution over multi-decade timescales, hinting at fundamental limits to the extent of local adaptation. Together, our results suggest that gut bacteria can evolve on human-relevant timescales, and they highlight the connections between these short-term evolutionary dynamics and longer-term evolution across hosts.
Acute physical exercise improves memory consolidation in humans via BDNF and endocannabinoid signaling
Authors: Bosch Blanca Marin , Bringard Aurélien , Logrieco Maria Grazia , Lauer Estelle , Imobersteg Nathalie , Thomas Aurélien , Ferretti Guido , Schwartz Sophie , Igloi Kinga 
Published: November 2017

AbstractRegular physical exercise enhances memory functions and neurogenesis in the hippocampus, an effect partially mediated by BDNF (Brain Derived Neurotrophic Factor). Acute exercise promotes the release of endocannabinoids (especially anandamide, AEA), which enhance BDNF release and improve hippocampal plasticity in rodents. How acute exercise affects BDNF and AEA levels and influences memory performance in humans remains to date unknown. Here we combined blood biomarkers, behavioral and fMRI measurements to assess the impact of acute physical exercise on associative memory and underlying neurophysiological mechanisms. For each participant, memory was tested after three conditions: rest, moderate or high exercise intensity. A long-term memory retest took place 3 months later. At both test and retest, memory performance increased after moderate but not high intensity exercise or rest. We also show that memory benefited from exercise-related increases in both AEA and BNDF levels: AEA boosted hippocampal activity during memory recall, while BDNF enhanced hippocampal memory representations and long-term performance.
Pollinator traits and competitive context shape dynamic foraging behavior in bee communities
Authors: Briggs Heather M. , Brosi Berry J. 
Published: November 2017

AbstractInterspecific interactions (e.g. competition) can dynamically shape individual and species-level resource use within communities. Understanding how interspecific competition between pollinators species shapes resource use is of particular interest because pollinator foraging behavior (“floral fidelity”) is directly linked to plant reproductive function through the movement of conspecific pollen. Through targeted species removals, this study aims to gain a predictive understanding of how interspecific competition can influence pollinator foraging behavior. We explore how traits—specifically pollinator tongue length, known to dictate pollinator resource partitioning—influence behavioral plasticity and drive dynamic interspecific interactions. Our results demonstrate that bee species vary in their floral fidelity and that tongue length explains a large part of this variation. Bees with shorter tongues move between plant species (floral infidelity) more often than bees with longer tongues. We did not find significant variation in the response of bee species to a reduction in interspecific competition, but rather saw a guild-wide reduction in floral fidelity in response to the removal of the dominant bee species Finally, our results suggest that tongue length of the most abundant bee species, a site-level attribute, explains much of the site-to-site variation in pollinator foraging behavior. In particular, we found that as the tongue length of the most abundant bee in the site increases, the site level foraging fidelity decreases. With global pollinator populations on the decline, novel interactions between plants and pollinators are likely to occur. Exploring how the competitive landscape shapes foraging plasticity will help us generalize to other plant pollinator systems and begin to better predict the functional implications of competitive interactions.
A neuronal mechanism underlying decision-making deficits during hyperdopaminergic states
Authors: Verharen Jeroen P.H. , de Jong Johannes W. , Roelofs Theresia J.M. , Huffels Christiaan F.M. , van Zessen Ruud , Luijendijk Mieneke C.M. , Hamelink Ralph , Willuhn Ingo , den Ouden Hanneke E.M. , van der Plasse Geoffrey , Adan Roger A.H. , Vanderschuren Louk J.M.J. 
Published: November 2017

AbstractHyperdopaminergic states in mental disorders are associated with disruptive deficits in decision-making. However, the precise contribution of topographically distinct mesencephalic dopamine pathways to decision-making processes remains elusive. Here we show, using a multidisciplinary approach, how hyperactivity of ascending projections from the ventral tegmental area (VTA) contributes to faulty decision-making in rats. Activation of the VTA-nucleus accumbens pathway leads to insensitivity to loss and punishment due to impaired processing of negative reward prediction errors. In contrast, activation of the VTA-prefrontal cortex pathway promotes risky decision-making without affecting the ability to choose the economically most beneficial option. Together, these findings show how malfunction of ascending VTA projections affects value-based decision-making, providing a mechanistic understanding of the reckless behaviors seen in substance abuse, mania, and after dopamine replacement therapy in Parkinson’s disease.
Beyond the Michaelis-Menten equation: Accurate and efficient estimation of enzyme kinetic parameters
Authors: Choi Boseung , Rempala Grzegorz A. , Kim Jae Kyoung 
Published: November 2017

ABSTRACTExamining enzyme kinetics is critical for understanding cellular systems and for using enzymes in industry. The Michaelis-Menten equation has been widely used for over a century to estimate the enzyme kinetic parameters from reaction progress curves of substrates, which is known as the progress curve assay. However, this canonical approach works in limited conditions, such as when there is a large excess of substrate over enzyme. Even when this condition is satisfied, the identifiability of parameters is not always guaranteed, and often not verifiable in practice. To overcome such limitations of the canonical approach for the progress curve assay, here we propose a Bayesian approach based on an equation derived with the total quasi-steady-state approximation. In contrast to the canonical approach, estimates obtained with this proposed approach exhibit little bias for any combination of enzyme and substrate concentrations. Importantly, unlike the canonical approach, an optimal experiment to identify parameters with certainty can be easily designed without any prior information. Indeed, with this proposed design, the kinetic parameters of diverse enzymes with disparate catalytic efficiencies, such as chymotrypsin, fumarase, and urease, can be accurately and precisely estimated from a minimal amount of timecourse data. A publicly accessible computational package performing the Bayesian inference for such accurate and efficient enzyme kinetics is provided.
Fungal chromatin mapping identifies BasR, as the regulatory node of bacteria-induced fungal secondary metabolism
Authors: Fischer Juliane , Müller Sebastian Y. , Netzker Tina , Jäger Nils , Gacek-Matthews Agnieszka , Scherlach Kirstin , Stroe Maria C. , García-Altares María , Pezzini Francesco , Schoeler Hanno , Reichelt Michael , Gershenzon Jonathan , Krespach Mario K. C. , Shelest Ekaterina , Schroeckh Volker , Valiante Vito , Heinzel Thorsten , Hertweck Christian , Strauss Joseph , Brakhage Axel A. 
Published: November 2017

AbstractThe eukaryotic epigenetic machinery is targeted by bacteria to reprogram the response of eukaryotes during their interaction with microorganisms. In line, we discovered that the bacteriumStreptomyces rapamycinicustriggered increased chromatin acetylation and thus activation of the silent secondary metabolismorsgene cluster leading to the production of orsellinic acid in the fungusAspergillus nidulans. Using this model we aim at understanding molecular mechanisms of communication between bacteria and eukaryotic microorganisms based on bacteria-triggered chromatin modification. By genome-wide ChIP-seq analysis of acetylated histone H3 (H3K9ac, H3K14ac) we uncovered the unique chromatin landscape inA. nidulansupon co-cultivation withS. rapamycinicus. Genome-wide acetylation of H3K9 correlated with increased gene expression, whereas H3K14 appears to function in transcriptional initiation by providing a docking side for regulatory proteins. In total, histones belonging to six secondary metabolism gene clusters showed higher acetylation during co-cultivation including theors, aspercryptin, cichorine, sterigmatocystin, anthrone and 2,4-dihydroxy-3-methyl-6-(2-oxopropyl)benzaldehyde gene cluster with the emericellamide cluster being the only one with reduced acetylation and expression. Differentially acetylated histones were also detected in genes involved in amino acid and nitrogen metabolism, signaling, and genes encoding transcription factors. In conjunction with LC-MS/MS and MALDI-MS imaging, molecular analyses revealed the cross-pathway control and Myb-like transcription factor BasR as regulatory nodes for transduction of the bacterial signal in the fungus. The presence ofbasRin other fungal species allowed forecasting the inducibility of ors-like gene clusters byS. rapamycinicusin these fungi, and thus their effective interaction with activation of otherwise silent gene clusters.
MYC activity is required for maintenance of the Neuromesodermal Progenitor signalling network and for correct timing of segmentation clock gene oscillations
Authors: Mastromina Ioanna , Verrier Laure , Storey Kate G. , Dale J. Kim 
Published: November 2017

AbstractThe Myc transcriptional regulators are implicated in a range of cellular functions, including proliferation, cell cycle progression, metabolism and pluripotency maintenance. Here, we investigated the expression, regulation and function of Myc during mouse embryonic axis elongation and segmentation. Expression of bothcMycandMycNin the domains where neuromesodermal progenitors (NMPs) and underlying caudal pre-somitic mesoderm (cPSM) cells reside is coincident WNT and FGF signals; factors known to maintain progenitors in an undifferentiated state. Pharmacological inhibition of MYC activity, downregulates expression of WNT/FGF components. In turn, we find thatcMycexpression is WNT, FGF and NOTCH regulated, placing it centrally in the signalling circuit that operates in the tail end that both sustains progenitors and drives maturation of the PSM into somites. Interfering with MYC function in the PSM, where it displays oscillatory expression, delays the timing of segmentation clock oscillations and thus of somite formation. In summary, we identify Myc as a component that links NMP maintenance and PSM maturation during the body axis elongation stages of mouse embryogenesis.Summary StatementMYC operates in a positive feedback loop with WNT/FGF signals to maintain the progenitors which facilitate body axis elongation while its activity is crucial for timing of the segmentation clock.
Abortion Law and Scotland: An Issue of What?
Authors: Thomson Jennifer 
Published: November 2017

AbstractIn recent years, several decisions have been made regarding the devolution of abortion laws from central government at Westminster to the devolved regions of the United Kingdom. This article considers the decision to devolve abortion law to Scotland. It addresses Westminster debates from the time, employing a discursive analysis to examine the arguments made for this legislative move. It argues that the debate was largely a proxy argument for the broader question of Westminster–Edinburgh relations and Scottish independence. It further argues that utilising abortion in this way is problematic, and politicises an area which is better seen as an issue solely of women's rights.
The Value of Going Green in the Hotel Industry: Evidence from Beijing
Authors: Zhang Li , Wu Jing , Liu Hongyu , Zhang Xiaoling 
Published: October 2017

AbstractBased on several unique datasets in Beijing, this article investigates the value of going green in the hotel industry by combining the traditional hedonic pricing model with the state‐of‐the‐art content analysis of online reviews. The results indicate that the rate of complaints about the indoor environmental quality of green hotels is roughly 19% lower than that for nongreen hotels. Hedonic regression analysis concludes that green hotels enjoy a significant room rate premium of 6.5% without reducing occupancy rates, mainly due to improved indoor environmental quality. Recognizing the presence of such cobenefits is likely to induce hoteliers to embrace green practices.
Channel Evolution Models as Predictors of Sediment Yield
Authors: Keane Tim D. , Sass Christopher K. 
Published: November 2017

AbstractThis paper recounts our predictions of channel evolution of the Black Vermillion River (BVR) and sediment yields associated with the evolutionary sequence. Channel design parameters allowed for the prediction of stable channel form and coincident sediment yields. Measured erosion rates and basin‐specific bank erosion curves aided in prediction of the stream channel succession time frame. This understanding is critical in determining how and when to mitigate a myriad of instability consequences. The BVR drains approximately 1,062 km2 in the glaciated region of Northeast Kansas. Once tallgrass prairie, the basin has been modified extensively for agricultural production. As such, channelization has shortened the river by nearly 26 km from pre‐European dimensions; shortening combined with the construction of numerous flow‐through structures have produced dramatic impacts on discharge and sediment dynamics. Nine stream reaches were established within three main tributaries of the BVR in 2007. Reaches averaged 490 m in length, were surveyed, and assessed for channel stability, while resurveys were conducted annually through 2010 to monitor change. This work illustrates the association of current stream state, in‐channel sediment contributions, and prediction of future erosion rates based on stream evolution informed by multiple models. Our findings suggest greater and more rapid sedimentation of a federal reservoir than has been predicted using standard sediment prediction methods.
Enhanced recovery after surgery using uniportal video‐assisted thoracic surgery for lung cancer: A preliminary study
Authors: Huang Haitao , Ma Haitao , Chen Shaomu 
Published: October 2017

BackgroundThis study investigated the clinical efficiency of enhanced recovery after surgery (ERAS) using uniportal video‐assisted thoracoscopic surgery for lung cancer.MethodsThe clinical data of 83 patients with early‐stage non‐small cell lung cancer (NSCLC) at the First Affiliated Hospital of Soochow University from January 2016 to February 2017 were retrospectively analyzed. ERAS was applied to 38 patients (ERAS group), while 45 patients received conventional surgical treatment (control group). The operative duration, number of lymph nodes retrieved, blood loss, visual analogue scale (VAS), postoperative duration of chest tube placement, length of hospital stay, and postoperative complications were compared between the groups.ResultsSurgeries were conducted successfully in all patients, and no mortality occurred during the perioperative period. The ERAS group had better VAS on the third postoperative day, shorter chest tube duration, and shorter length of hospital stay (P < 0.05). No differences between the groups in terms of operative duration, number of lymph nodes retrieved, blood loss, VAS on the first postoperative day, or complication rate were found (P > 0.05).Conclusions
ERAS using uniportal video‐assisted thoracoscopic surgery for NSCLC patients is safe and practicable, and could also reduce the length of hospital stay.
Learning from the Law. A review of 21 years of litigation for pain during caesarean section
Authors: McCombe K. , Bogod D. G. 
Published: November 2017

SummaryThe large majority of caesarean sections in the UK are now carried out under neuraxial anaesthesia. Although this technique is widely accepted as being the safest option in most circumstances, the use of regional anaesthesia increases the risk of patients experiencing intra‐operative discomfort or pain. Pain during operative obstetric delivery is the commonest successful negligence claim relating to regional anaesthesia against obstetric anaesthetists in the UK. In the following article, using a database of over 360 cases spanning 21 years, we break down and examine the recurrent components of medicolegal claims concerning pain during caesarean section and consider how anaesthetists might avoid litigation.
Changes in oxygen saturation and the retinal nerve fibre layer in patients with optic neuritis – a pilot study
Authors: Svrčinová Tereza , Mareš Jan , Chrapek Oldřich , Šínová Irena , Rybariková Martina , Otruba Pavel , Kaňovský Petr , Šín Martin 
Published: November 2017

AbstractPurposeAssessment of retinal oxygen saturation, thickness of a retinal nerve fibre layer (RNFL) and functional changes in the optic nerve during optic neuritis (ON) in patients with multiple sclerosis (MS).MethodsThirty‐two patients withONdue toMSwithin 3 months of onset of symptoms were enrolled [22 females, 10 males, age 34 ± 9 years, median 32.5 years, 22 patients with the clinically isolated syndrome (CIS), 10 patients with relapsing‐remitting from ofMS(RRMS)]. All patients were examined using optical coherence tomography (OCTmodel 4000, Carl Zeiss Meditec, Dublin, CA, USA), automatic optical oximetry (Oxymap ehf, Reykjavik, Iceland) and using visual evoked potentials (VEP) (Metronic Keypoint®, Minneapolis, MN,USA).ResultsArterio‐venous difference (AVD) was increased in patientsONaffected eye compared to patients' unaffected eye (PUE) [34.2 ± 4.7 versus 31.3 ± 4.6, p = 0.044 (mean ± standard deviation)]. No statistically significant difference was found in vessel oxygen saturation as well as inRNFLthickness inONaffected eyes when compared to unaffectedMSeyes and healthy individuals. Significantly lower optic nerve conduction velocity was found in the affected eye when compared to unaffectedMSeye and healthy (p < 0.0001 for both comparisons). No correlation between oxygen saturation values andVEPwas observed in patients withMS.ConclusionTheAVDin oxygen saturation is altered in patients with acuteON. In the early stage ofON,AVDcould reflect inflammatory and metabolic changes in the affected eye. Therefore, oximetry could be used as another diagnostic method inMSpatients in suspicion ofON. This result would be promising for future investigation in this field.