bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lichens buffer tundra microclimate more than the expanding shrub Betula nana
Authors: Mallen-Cooper Max , Graae Bente J , Cornwell Will K 
Published: March 2021

Abstract

Background and Aims
In tundra systems, soil-borne lichens are often the dominant groundcover organisms, and act to buffer microclimate extremes within or at the surface of the soil. However, shrubs are currently expanding across tundra systems, potentially causing major shifts in the microclimate landscape.

Methods
Here, we compared soil temperature and moisture underneath the dwarf birch Betula nana and seven abundant lichen species in sub-alpine Norway. We also examined mixtures of lichens and dwarf birch – an intermediate phase of shrubification – and measured several functional traits relating to microclimate.

Key Results
We found that all lichen species strongly buffered the daily temperature range, on average reducing maximum temperatures by 6.9 °C (± 0.7 s.d.) and increasing minimum temperatures by 1.0 °C (± 0.2 s.d.) during summer. The dwarf birch had a much weaker effect (maximum reduced by 2.4 ± 5.0 °C and minimum raised by 0.2 ± 0.9 °C). In species mixtures, the lichen effect predominated, affecting temperature extremes by more than would be expected from their abundance. Lichens also tended to reduce soil moisture, which could be explained by their ability to intercept rainfall. Our trait measurements under laboratory conditions suggest that, on average, lichens can completely absorb a 4.09 mm (± 1.81 s.d.) rainfall event, which might be an underappreciated part of lichen–vascular plant competition in areas where summer rainfall events are small.

Conclusions
In the context of shrubification across tundra systems, our findings suggest that lichens will continue to have a large effect on microclimate until they are fully excluded, at which point microclimate extremes will increase greatly.
New framework for recombination and adaptive evolution analysis with application to the novel coronavirus SARS-CoV-2
Authors: Wang Yinghan , Zeng Jinfeng , Zhang Chi , Chen Cai , Qiu Zekai , Pang Jiali , Xu Yutian , Dong Zhiqi , Song Yanxin , Liu Weiying , Dong Peipei , Sun Litao , Chen Yao-Qing , Shu Yuelong , Du Xiangjun 
Published: March 2021

Abstract
The 2019 novel coronavirus (SARS-CoV-2) has spread rapidly worldwide and was declared a pandemic by the WHO in March 2020. The evolution of SARS-CoV-2, either in its natural reservoir or in the human population, is still unclear, but this knowledge is essential for effective prevention and control. We propose a new framework to systematically identify recombination events, excluding those due to noise and convergent evolution. We found that several recombination events occurred for SARS-CoV-2 before its transfer to humans, including a more recent recombination event in the receptor-binding domain. We also constructed a probabilistic mutation network to explore the diversity and evolution of SARS-CoV-2 after human infection. Clustering results show that the novel coronavirus has diverged into several clusters that cocirculate over time in various regions and that several mutations across the genome are fixed during transmission throughout the human population, including D614G in the S gene and two accompanied mutations in ORF1ab. Together, these findings suggest that SARS-CoV-2 experienced a complicated evolution process in the natural environment and point to its continuous adaptation to humans. The new framework proposed in this study can help our understanding of and response to other emerging pathogens.
Attainment and maintenance of pubertal cyclicity may predict reproductive longevity in beef heifers
Authors: Nafziger Sarah R , Tenley Sarah C , Summers Adam F , Abedal-Majed Mohamed A , Hart Mariah , Bergman Jeffrey W , Kurz Scott G , Davis John S , Wood Jennifer R , Cupp Andrea S 
Published: March 2021

Abstract
We hypothesized the manner that heifers achieve puberty may indicate their future reproductive longevity. Heifers with discontinued or delayed cyclicity during puberty attainment may have irregular reproductive cycles, anovulation, and infertility in their first breeding season contributing to a shorter reproductive lifespan. Therefore, plasma progesterone (P4) was measured from weaning to breeding on 611 heifers born 2012–2017 and four pubertal classifications were identified: (1) Early; P4 ≥ 1 ng/ml &lt; March 12 with continued cyclicity, (2) Typical; P4 ≥ 1 ng/ml ≥ March 12 with continued cyclicity, (3) Start-Stop; P4 ≥ 1 ng/ml but discontinued cyclicity, and (4) Non-Cycling; no P4 ≥ 1 ng/ml. Historical herd records indicated that 25% of heifers achieved puberty prior to March 12th in the 10 years prior to the study. Start-Stop and Non-Cycling yearling heifers were lighter indicating reduced growth and reproductive maturity traits compared with Early/Typical heifers. In addition, Non-Cycling/Start-Stop heifers were less responsive to prostaglandin F2 alpha (PGF2α) to initiate estrous behavior and ovulation to be artificially inseminated. Non-Cycling heifers had fewer reproductive tract score-5 and reduced numbers of calves born in the first 21-days-of-calving during their first breeding season. Within the Start-Stop classification, 50% of heifers reinitiated cyclicity with growth traits and reproductive parameters that were similar to heifers in the Early/Typical classification while those that remained non-cyclic were more similar to heifers in the Non-Cycling group. Thus, heifers with discontinued cyclicity or no cyclicity during puberty attainment had delayed reproductive maturity resulting in subfertility and potentially a shorter reproductive lifespan.
Trust your gut: vagal nerve stimulation in humans improves reinforcement learning
Authors: Weber Immo , Niehaus Hauke , Krause Kristina , Molitor Lena , Peper Martin , Schmidt Laura , Hakel Lukas , Timmermann Lars , Menzler Katja , Knake Susanne , Oehrn Carina R 
Published: March 2021

Abstract
Whereas the effect of vagal nerve stimulation on emotional states is well established, its effect on cognitive functions is still unclear. Recent rodent studies show that vagal activation enhances reinforcement learning and neuronal dopamine release. The influence of vagal nerve stimulation on reinforcement learning in humans is still unknown. Here, we studied the effect of transcutaneous vagal nerve stimulation on reinforcement learning in eight long-standing seizure-free epilepsy patients, using a well-established forced-choice reward-based paradigm in a cross-sectional, within-subject study design. We investigated vagal nerve stimulation effects on overall accuracy using non-parametric cluster-based permutation tests. Furthermore, we modelled sub-components of the decision process using drift-diffusion modelling. We found higher accuracies in the vagal nerve stimulation condition compared to sham stimulation. Modelling suggests a stimulation-dependent increase in reward sensitivity and shift of accuracy-speed trade-offs towards maximizing rewards. Moreover, vagal nerve stimulation was associated with increased non-decision times suggesting enhanced sensory or attentional processes. No differences of starting bias were detected for both conditions. Accuracies in the extinction phase were higher in later trials of the vagal nerve stimulation condition, suggesting a perseverative effect compared to sham. Together, our results provide first evidence of causal vagal influence on human reinforcement learning and might have clinical implications for the usage of vagal stimulation in learning deficiency.
Development and Validation of Two New Methods for the Determination of Rilmenidine in Bulk and Pharmaceutical Preparation
Authors: Özdemir Elif , Ergin Kizilçay Gamze , Ertürk Toker Sıdıka 
Published: March 2021

Abstract
In the present study, two new methods were developed and validated for the determination of rilmenidine in bulk and pharmaceutical preparation. Both methods are based on a derivatization reaction using 4-chloro-7-nitro-1,2,3-benzoxadiazole (NBD-Cl) as a fluorogenic substance. The drug reagent derivatives were formed by the reaction of rilmenidine with NBD-Cl at pH 9.0 at 70°C for 40 min. The reaction mixtures were analyzed by spectrofluorimetry in the first method and high performance liquid chromatography (HPLC) in the second method. Derivatives were determined at λex 493 nm and at λem 536 nm in the spectrofluorimetric method. The separation was performed place on a Phenomenex, C18 column (250 × 4.6 mm, 5 μm i.d) using a mobile phase comprising 0.2% formic acid and acetonitrile gradient elution mode in the HPLC method. Analytes were detected by a fluorescence detector at the same wavelength. The methods were validated for limit of quantitation, linearity, robustness, recovery, limit of detection, precision and accuracy. Calibration curves for the first and second methods were found to be linear in the range of 2.0–12.0 and 250–2000 ng/mL, respectively. Detection limits for the spectrofluorimetric and HPLC methods were calculated as 0.16 and 18.28 ng/mL, respectively. The validated methods were applied successfully to the determination of rilmenidine in bulk and pharmaceutical preparation.
Impact of Systemic Corticosteroids on Mortality in Older Adults With Critical COVID-19 Pneumonia
Authors: Piniella-Ruiz Esther , Bellver-Álvarez María Teresa , Mestre-Gómez Beatriz , Escolano-Fernández Belén , Vinat-Prado Sara , Cabezas-Olea Rita , Acedo-Gutiérrez María Soledad , Akasbi-Montalvo Mirian , Ryan-Murua Pablo , Bustamante-Fermosel Ana , Muñoz-Rivas Nuria , Santamaría-García Carmen , Pardo-Guimerá Virginia , Ulla-Anés Mariano , Franco-Moreno Anabel , Torres-Macho Juan 
Published: March 2021

Abstract

Background
The most susceptible population group to critical and fatal coronavirus disease 2019 (COVID-19) is older adults. In severe acute respiratory syndrome coronavirus 2 infection, the host immune response is thought to play a key role in the pathophysiological effects of lung damage. Therefore, corticosteroid therapy could modulate inflammation-mediated pulmonary injury and thereby reduce progression to severe respiratory failure and death. The aim of this study was to analyze the safety and clinical efficacy of corticosteroid therapy in older adults with severe COVID-19 pneumonia.

Method
We reviewed the clinical records of confirmed COVID-19 patients aged 75 years or older admitted to our hospital over a 3-month period (March 1–May 31, 2020). A total of 143 patients were included in the study cohort. From 2 April, 2020, in accordance with World Health Organization guidance on COVID-19, our hospital protocol added corticosteroid for COVID-19 treatment. We compared in-hospital mortality among patients with critical COVID-19 who received corticosteroids therapy and those who did not.

Results
In total, 88 patients (61.5%) were treated with corticosteroids, and 55 patients (38.4%) were not. Both groups were similar in baseline characteristics. The median age was 85 years (interquartile range: 82–89), and 61.5% (88/143) were male. In-hospital mortality was lower in the corticosteroid group (68.2%) compared with patients in the noncorticosteroid group (81.8%). Treatment with corticosteroids was an independent survival factor (hazard ratio: 0.61; 95% CI: 0.41–0.93; p = .006).

Conclusions
In critically ill older adults with COVID-19 pneumonia, the use of corticosteroid treatment resulted in lower mortality without severe adverse events.
Impaired Cognitive Flexibility Induced by Chronic Cerebral Hypoperfusion in the 5XFAD Transgenic Mouse Model of Mixed Dementia
Authors: Kim Min-Soo , Bang Jihye , Kim Bu-Yeo , Jeon Won Kyung 
Published: March 2021

Abstract
Cerebrovascular lesions are widely prevalent in patients with Alzheimer’s disease (AD), but their relationship to the pathophysiology of AD remains poorly understood. An improved understanding of the interaction of cerebrovascular damage with AD is crucial for the development of therapeutic approaches. Herein, we investigated the effects of chronic cerebral hypoperfusion (CCH) in a 5XFAD transgenic (Tg) mouse model of AD. We established CCH conditions in both Tg and non-Tg mice by inducing unilateral common carotid artery occlusion (UCCAO). Cognitive performance in mice was evaluated, and their brain tissue was examined for amyloid-beta (Aβ) pathology to elucidate possible mechanisms. We found that UCCAO-operated Tg mice showed impaired cognitive flexibility in the reversal phase of the hidden-platform water maze task compared to sham-operated Tg mice. Interestingly, UCCAO-operated Tg mice used fewer spatial cognitive strategies than sham-operated Tg mice during reversal learning. These cognitive deficits were accompanied by increased Aβ plaque burden and Aβ42 levels in the hippocampus and prefrontal cortex, 2 regions that play essential roles in the regulation of cognitive flexibility. Furthermore, changes in cognitive flexibility are strongly correlated with the expression levels of enzymes related to Aβ clearance, such as neprilysin and insulin-degrading enzymes. These findings suggest that, in 5XFAD mice, impaired cognitive flexibility is related to CCH, and that Aβ clearance might be involved in this process.
Serum and Cervicovaginal Fluid Antibody Profiling in Herpes Simplex Virus–Seronegative Recipients of the HSV529 Vaccine
Authors: Wang Kening , Dropulic Lesia , Bozekowski Joel , Pietz Harlan L , Jegaskanda Sinthujan , Dowdell Kennichi , Vogel Joshua S , Garabedian Doreen , Oestreich Makinna , Nguyen Hanh , Ali Mir A , Lumbard Keith , Hunsberger Sally , Reifert Jack , Haynes Winston A , Sawyer Jaymie R , Shon John C , Daugherty Patrick S , Cohen Jeffrey I 
Published: March 2021

Abstract
Previous herpes simplex virus type 2 (HSV-2) vaccines have not prevented genital herpes. Concerns have been raised about the choice of antigen, the type of antibody induced by the vaccine, and whether antibody is present in the genital tract where infection occurs. We reported results of a trial of an HSV-2 replication-defective vaccine, HSV529, that induced serum neutralizing antibody responses in 78% of HSV-1–/HSV-2– vaccine recipients. Here we show that HSV-1–/HSV-2– vaccine recipients developed antibodies to epitopes of several viral proteins; however, fewer antibody epitopes were detected in vaccine recipients compared with naturally infected persons. HSV529 induced antibodies that mediated HSV-2–specific natural killer (NK) cell activation. Depletion of glycoprotein D (gD)–binding antibody from sera reduced neutralizing titers by 62% and NK cell activation by 81%. HSV-2 gD antibody was detected in cervicovaginal fluid at about one-third the level of that in serum. A vaccine that induces potent serum antibodies transported to the genital tract might reduce HSV genital infection.
Are We Really Painting the Devil on the Walls? Polarization and Its Drivers in Sub-Saharan Africa in the Past Two Decades
Authors: Clementi Fabio , Fabiani Michele , Molini Vasco , Zizzamia Rocco 
Published: March 2021

Abstract
The development path of Sub-Saharan Africa (SSA) over the past two decades has been characterized by sluggish poverty reduction occurring alongside robust economic growth. Applying polarization measures to comparable survey data from 24 SSA countries, we find that there has been a generalizable increase in polarization over the past two decades—and in particular, an increased concentration of households in the lower tail of the welfare distribution of SSA countries. The polarization process is further analyzed by identifying the main drivers and singling out the effect of different covariates at different points in the consumption distribution. This investigation reveals that the drivers of polarization are relatively similar across SSA: demographic, urban/rural, regional variables and access to basic infrastructure are found to be the most important drivers of polarization in many countries.
Late-time cosmic evolution of dust: solving the puzzle
Authors: Ferrara Andrea , Peroux Celine 
Published: March 2021

ABSTRACT
Dust is an essential ingredient of galaxies, determining the physical and chemical conditions in the interstellar medium. Several complementary observational evidences indicate that the cosmic dust mass density significantly drops from redshift z = 1 to z = 0. Clearly, and for the first time during cosmic evolution, dust must be destroyed more rapidly than it is formed. By considering the dust production/destruction processes acting in this cosmic time lapse, we find that the drop can be explained if dust is mainly destroyed by astration (49 per cent contribution in the fiducial case) and supernova (SN) shocks within galaxies (42 per cent). Our results further imply that on average each SN destroys only $M_{\mathrm{ d},\mathrm{ sn}} =0.45\, \mathrm{ M}_\odot$ of dust, i.e. 5–10 times less than usually assumed, with a hard upper limit of Md,sn &lt; 3.0 M⊙ set by the available metal budget and maximal grain growth. The lower efficiency might be explained by effective shielding of dust against shock processing in pre-SN wind shells.
New insights into star cluster evolution towards energy equipartition
Authors: Pavlík Václav , Vesperini Enrico 
Published: March 2021

ABSTRACT
We present the results of a study aimed at exploring the evolution towards energy equipartition in star cluster models with different initial degrees of anisotropy in the velocity distribution. Our study reveals a number of novel aspects of the cluster dynamics and shows that the rate of evolution towards energy equipartition (i) depends on the initial degree of radial velocity anisotropy – it is more rapid for more radially anisotropic systems; and (ii) differs for the radial and the tangential components of the velocity dispersion. (iii) The outermost regions of the initially isotropic system evolve towards a state of ‘inverted’ energy equipartition in which high-mass stars have a larger velocity dispersion than low-mass stars – this inversion originates from the mass dependence of the tangential velocity dispersion whereas the radial velocity dispersion shows no anomaly. Our results add new fundamental elements to the theoretical framework needed to interpret the wealth of recent and upcoming observational studies of stellar kinematics in globular clusters, and shed further light on the link between the clusters’ internal kinematics, their formation, and evolutionary history.
Demographic History, Adaptation, and NRAP Convergent Evolution at Amino Acid Residue 100 in the World Northernmost Cattle from Siberia
Authors: Buggiotti Laura , Yurchenko Andrey A , Yudin Nikolay S , Vander Jagt Christy J , Vorobieva Nadezhda V , Kusliy Mariya A , Vasiliev Sergei K , Rodionov Andrey N , Boronetskaya Oksana I , Zinovieva Natalia A , Graphodatsky Alexander S , Daetwyler Hans D , Larkin Denis M 
Published: March 2021

AbstractNative cattle breeds represent an important cultural heritage. They are a reservoir of genetic variation useful for properly responding to agriculture needs in the light of ongoing climate changes. Evolutionary processes that occur in response to extreme environmental conditions could also be better understood using adapted local populations. Herein, different evolutionary histories of the world northernmost native cattle breeds from Russia were investigated. They highlighted Kholmogory as a typical taurine cattle, whereas Yakut cattle separated from European taurines approximately 5,000 years ago and contain numerous ancestral and some novel genetic variants allowing their adaptation to harsh conditions of living above the Polar Circle. Scans for selection signatures pointed to several common gene pathways related to adaptation to harsh climates in both breeds. But genes affected by selection from these pathways were mostly different. A Yakut cattle breed-specific missense mutation in a highly conserved NRAP gene represents a unique example of a young amino acid residue convergent change shared with at least 16 species of hibernating/cold-adapted mammals from six distinct phylogenetic orders. This suggests a convergent evolution event along the mammalian phylogenetic tree and fast fixation in a single isolated cattle population exposed to a harsh climate.
From grieving to healing: moving forward a year after COVID-19
Authors: Corpuz Jeff Clyde G 
Published: March 2021

Abstract
This paper addresses the many complex and traumatic losses brought by the coronavirus disease 2019 pandemic. During this crisis, it is important to grieve what has been lost, and it is also important to find meaning and hope in how life has changed. Conversely, there is no one size fits all formula for healing and coping with loss. Healing occurs in phases where one is moving in and out of different emotions. The saying ‘time heals all wounds’ is only partially correct because, for prolonged grief, time is not the solution.
Inhibition Kinetics of 16 Organophosphorus Pesticides or Their Active Metabolites on Erythrocyte Acetylcholinesterase From Humans and Rats
Authors: Meek Edward C , Reiss Richard , Crow John Allen , Chambers Janice E 
Published: March 2021

Abstract
Inhibition kinetics assays were conducted with 16 commercial organophosphate (OP) pesticides or their metabolites on acetylcholinesterase (AChE) in erythrocyte “ghost” preparations from 18 individual humans (both sexes; adults, juveniles, and cord blood samples; mixed races/ethnicities) and pooled samples from adult rats (both sexes). A well-established spectrophotometric assay using acetylthiocholine as substrate and a chromogen was employed. The kinetic parameters bimolecular rate constant (ki), dissociation constant (KI), and phosphorylation constant (kp) were calculated for each compound. As expected, a wide range of potencies were displayed among the tested compounds. Statistical analysis of the resultant data indicated no differences in sex, age, or race/ethnicity among the human samples that are unexpected based on chance (4.2% statistically significant out of 48 parameters calculated) and no differences between the sexes in rats. The bimolecular rate constants for 10 of the compounds were not statistically different between rats and humans. The data indicate that, consistent with the high level of conservation of AChE among species and the fact that AChE at different locations within a species arises from the same gene, the inhibition kinetic parameters calculated from rat erythrocyte ghost preparations should be useful in estimating potencies of OP compounds on target AChE in humans. Additionally, the data indicate that differences in sensitivities among individual humans were not apparent.
Prevalence of viral hepatitis B and C in Sierra Leone—current knowledge and knowledge gaps: a narrative review
Authors: Lakoh Sulaiman , García-Tardón Noemí , Adekanmbi Olukemi , van der Valk Marc , Smith Samuel J , Grobusch Martin P 
Published: March 2021

AbstractThere are no comprehensive data on viral hepatitis from Sierra Leone; however, a huge disease burden has been observed in different subpopulations. This review summarizes available data on hepatitis B and C virus (HBV and HCV) prevalence in Sierra Leone and identifies knowledge gaps. Despite the non-uniformity of the studies and the lack of systematic case recording, different reports published in recent decades yielded a hepatitis B prevalence of 8.7% among healthcare workers, 11.3% among pregnant women, 15.2% among blood donors and 16.7% in school-age children. The actual HBV prevalence in the general population was reported as 21.7%; similar to what was reported for people living with human immunodeficiency virus (PLHIV). HCV prevalence is 8% and 7% in male and female blood donors, respectively, 4.1% in PLHIV and 2.0% in school children. There are significant knowledge gaps regarding the prevalence of viral hepatitis B and C in Sierra Leone, despite the high burden reported in a few studies. There are limited programmatic interventions on the control and prevention of viral hepatitis in the country. Therefore, well-structured representative studies should provide a solid understanding of the true prevalence of hepatitis B and C to inform best possible public health measures in Sierra Leone.