bluuebunny/crossref_metadata_2025 huggingface dataset:
An Unusual Route for
p
-Aminobenzoate Biosynthesis in Chlamydia trachomatis Involves a Probable Self-Sacrificing Diiron Oxygenase
Authors: Macias-Orihuela Yamilet , Cast Thomas , Crawford Ian , Brandecker Kevin J. , Thiaville Jennifer J. , Murzin Alexey G. , de Crécy-Lagard Valérie , White Robert H. , Allen Kylie D.
Published: July 2020

Chlamydia trachomatis
is the most reported sexually transmitted infection in the United States and the leading cause of infectious blindness worldwide. Unlike many other intracellular pathogens that have undergone reductive evolution,
C. trachomatis
is capable of
de novo
biosynthesis of the essential cofactor tetrahydrofolate using a noncanonical pathway. Here, we identify the biosynthetic precursor to the
p
-aminobenzoate (pABA) portion of folate in a process that requires the CT610 enzyme from
C. trachomatis
. We further provide evidence that CT610 is a self-sacrificing or “suicide” enzyme that uses its own amino acid residue(s) as the substrate for pABA synthesis. This work provides the foundation for future investigation of this chlamydial pABA synthase, which could lead to new therapeutic strategies for
C. trachomatis
infections.
Structural Basis and Evolution of Glycan Receptor Specificities within the Polyomavirus Family
Authors: Ströh Luisa J. , Rustmeier Nils H. , Blaum Bärbel S. , Botsch Josephine , Rößler Philip , Wedekink Florian , Lipkin W. Ian , Mishra Nischay , Stehle Thilo
Published: July 2020

Virus attachment to cell surface receptors is critical for productive infection. In this study, we have used a structure-based approach to investigate the cell surface recognition event for New Jersey polyomavirus (NJPyV) and human polyomavirus 12 (HPyV12). These viruses belong to the polyomavirus family, whose members target different tissues and hosts, including mammals, birds, fish, and invertebrates. Polyomaviruses are nonenveloped viruses, and the receptor-binding site is located in their capsid protein VP1. The NJPyV capsid features a novel sialic acid-binding site that is shifted in comparison to other structurally characterized polyomaviruses but shared with a closely related simian virus. In contrast, HPyV12 VP1 engages terminal sialic acids in a manner similar to the human
Trichodysplasia spinulosa
-associated polyomavirus. Our structure-based phylogenetic analysis highlights that even distantly related avian polyomaviruses possess the same exposed sialic acid-binding site. These findings complement phylogenetic models of host-virus codivergence and may also reflect past host-switching events.
An Entry-Triggering Protein ofEhrlichiaIs a New Vaccine Candidate against Tick-Borne Human Monocytic Ehrlichiosis
Authors: Budachetri Khemraj , Teymournejad Omid , Lin Mingqun , Yan Qi , Mestres-Villanueva Mariella , Brock Guy Nathaniel , Rikihisa Yasuko
Published: July 2020

The incidence of tick-borne diseases has risen dramatically in the past two decades and continues to rise. Discovered in 1986 and designated a nationally notifiable disease in 1998 by the Centers for Disease Control and Prevention, human monocytic ehrlichiosis, which is caused by the bacteriumEhrlichia chaffeensis, is one of the most prevalent, life-threatening, emerging tick-borne zoonoses in the United States. We investigated the role of theE. chaffeensisprotein EtpE in transmission of the bacterium from tick to human cells and in vaccinated dogs with EtpE to assess the efficacy of vaccination againstE. chaffeensis-infected tick challenge. Our results help fill gaps in our understanding ofE. chaffeensis-derived protective antigens that could be used in a candidate vaccine for immunization of humans to counter tick-transmitted ehrlichiosis.
Untangling Species-Level Composition of Complex Bacterial Communities through a Novel Metagenomic Approach
Authors: Milani Christian , Alessandri Giulia , Mangifesta Marta , Mancabelli Leonardo , Lugli Gabriele Andrea , Fontana Federico , Longhi Giulia , Anzalone Rosaria , Viappiani Alice , Duranti Sabrina , Turroni Francesca , Costi Renato , Annicchiarico Alfredo , Morini Andrea , Sarli Leopoldo , Ossiprandi Maria Cristina , van Sinderen Douwe , Ventura Marco
Published: July 2020

We developed a novel method for accurate cataloguing of bacterial communities at (sub)species level involving amplification of the internal transcribed spacer (ITS) region through optimized primers, followed by next-generation sequencing and taxonomic classification of amplicons by means of a comprehensive database of bacterial ITS sequences. Host-associated, food, and environmental matrices were employed to test the performance of the microbial ITS profiling pipeline. Moreover, mucosal biopsy samples from colorectal cancer patients were analyzed to demonstrate the scientific relevance of this profiling approach in a clinical setting through identification of putative novel biomarkers. The results indicate that the ITS-based profiling pipeline proposed here represents a key metagenomic tool with major relevance for research, industrial, and clinical settings.
The Behavior of Amphibians Shapes Their Symbiotic Microbiomes
Authors: Xu Liangliang , Xiang Mengmeng , Zhu Wei , Zhang Mengjie , Chen Hua , Huang Jin , Chen Youhua , Chang Qing , Jiang Jianping , Zhu Lifeng
Published: July 2020

Understanding the interactions between host behavior and microbiome dynamics remains an outstanding priority in the field of microbial ecology. Here, we provide the reader with a simple example of how the behavior and living environment of wild amphibians shape their symbiotic microbiome externally (on the skin) and internally (in the stomach and gut).
Contrasting prenatal nutrition and environmental exposures in association with birth weight and cognitive function in children at 7 years
Authors: Gennings Chris , Wolk Alicja , Hakansson Niclas , Lindh Christian , Bornehag Carl-Gustaf
Published: July 2020

Background

Good nutrition is essential for individual health, a notion that is particularly true during pregnancy. We have used a nutrition index that measures the adequacy of one’s diet relative to the unique nutritional needs of individuals due to, for example, their activity level, dietary restrictions, lifestyle and body size. The use of this personalised metric of dietary nutritiousness in the analysis of prenatal environmental exposures and developmental outcomes permits testing for potential mitigating effects of good nutrition. We also provide an analysis strategy for investigating the balance in beneficial food sources which are also the source of environmental toxicants.

Methods

A holistic measure of nutrition,My Nutrition Index(MNI), measures the nutrient quality (ie, ‘nutritiousness’) of a specified daily diet. MNI is calculated based on quantification of dozens of macronutrients and micronutrients that are specific to an individual’s nutritional needs by incorporating dietary restrictions, subject characteristics, activity level and health behaviours. The Swedish Environmental, Longitudinal, Mother and child, Asthma and allergy Study is a Swedish pregnancy cohort, with prenatal endocrine disrupting chemicals (EDCs) exposure and dietary data available. This makes it possible to test for the potential mitigating effects of good nutrition on health and development effects in offspring from EDCs.

Results

Using prenatal Food Frequency Questionnaire data to construct an individual’s MNI, the index was significantly and positively associated with important metabolic outcome (as measured by birth weight) and cognitive function at age 7 years (as measured by WISC IQ) in children when adjusted for covariates and prenatal concentrations of an EDC. In a stratified analysis of ‘low’ and ‘high’ fish consumption, a potential source of perfluoro-octanesulfonic acid (PFOS), the association between PFOS and birth weight was diminished in the high consumption group compared with the low consumption group.

Conclusions

Thus, MNI is evidently a metric of the general nutritiousness of daily diets and is useful in environmental health studies in representing the impact of good nutrition, even during pregnancy.
Money-oriented risk-takers or deliberate decision-makers: a cross-sectional survey study of participants in controlled human infection trials
Authors: Hoogerwerf Marie-Astrid , de Vries Martine , Roestenberg Meta
Published: July 2020

Objective

To quantitatively investigate the motivations, decision-making and experience of participants in controlled human infection (CHI) studies.

Design

Cross-sectional descriptive survey study.

Setting

Previous participants of CHI studies at the Leiden Controlled Human Infection Center, control group of students from Leiden University.

Participants

61 previous participants and 156 controls.

Measurements

Ranking of motivational and decisional factors, risk propensity score and multiple-choice questions on experience of trial participation and ethical aspects of CHI studies.

Results

Motivating factors for participants were contributing to science (81%), contributing to research that may benefit developing countries (72%) and the financial compensation (63%). For 51% of participants, a reason other than financial compensation was the most important motivational factor. Participants considered trust in the study team (70%), time investment (63%), severity of symptoms (54%), chance of developing symptoms (54%) and whether it is an easy way to make money (54%) in their decision to participate. Most CHI participants (84%) were proud of their participation, would advise others to participate (89%) and would participate in a similar trial again (85%). CHI participants had a higher risk propensity score than students (estimated difference 0.9, p<0.001).

Conclusion

Although financial compensation is important, the motivations for participants in a CHI study are diverse and participants make a balanced appraisal of risks and burden before participating.
Pathways to psychiatric care and factors associated with delayed help-seeking among patients with mental illness in Northern Ethiopia: a cross-sectional study
Authors: Teshager Senait , Kerebih Habtamu , Hailesilassie Hailemariam , Abera Mubarek
Published: July 2020

Objective

This study aimed to assess pathways to psychiatric care and factors associated with delayed help-seeking among patients with mental illness in Northern Ethiopia using the WHO Pathway Study Encounter Form.

Design

A cross-sectional study design was used.

Setting

Data were collected using face-to-face interview from patients with various diagnoses of mental illness attending outpatient treatment at Ayder Comprehensive Specialized Hospital in Mekelle City, Tigray, Northern Ethiopia.

Participants

Participants who came to attend outpatient treatment during the study period were included in the study using consecutive sampling technique.

Outcome measures

Pathways to psychiatric care, delayed psychiatric treatment and factors affecting delayed psychiatric treatment.

Results

The median duration from problem onset to contact with first care provider was 4 weeks, whereas contact with modern psychiatric services was 52.0 weeks. Study participants who were single (adjusted OR (AOR)=2.91, 95% CI 1.19 to 7.11), divorced (AOR=3.73, 95% CI 1.33 to 10.49) and who perceived mental illness as shameful (AOR=3.29, 95% CI 1.15 to 9.41) had delayed treatment-seeking behaviour, whereas participants with no history of substance use (AOR=0.43, 95% CI 0.20 to 0.92) were less likely to have delayed treatment-seeking behaviour.

Conclusions

There is significant delay in seeking modern psychiatric treatment. Religious healers were the first source of help for mental illness. Majority of the respondents described that mental illness was due to supernatural causes. Stigma and lack of awareness about where treatment is available were barriers to seeking appropriate care.
How are social determinants of health represented in German medical education?: a qualitative content analysis of key-curricular documents
Authors: Hommes Franziska , Drees Simon , Geffert Karin , von Philipsborn Peter , Stratil Jan M
Published: July 2020

Objective

The WHO Commission on Social Determinants of Health (SDH) has called for a health workforce trained in recognising, understanding and acting on the SDH. However, little is known about how current medical education prepares graduates for this challenge. This study analyses the extent to which the German medical education incorporates content on SDH.

Design

Following a published protocol, in 2018, we conducted a qualitative and quantitative content analysis of three key document groups, defining and guiding what medical schools are expected to teach and what medical students are expected to know when graduating in Germany. We developed the coding system in a mixed inductive and deductive approach based on key WHO documents.

Setting

Medical schools and the medical education system in Germany.

Results

Important gaps exist in the representation of SDH in medical education in Germany. Between 3% and 27% of the analysed document-elements made reference to SDH and only 0%–3% of those document elements made explicit references to SDH. While some aspects were covered widely (eg, topics of occupational health, early childhood development and hygiene), other topics such as health inequalities or determinants outside of the healthcare system were not or hardly represented.

Conclusions

A stronger and more explicit representation of SDH in German medical education is needed to prepare the new health workforce for current and future challenges in our globalised world and for medical schools to be socially accountable.
Women’s experiences of self-administration of misoprostol at home as part of early medical abortion: a qualitative evaluation
Authors: Harden Jeni , Ancian Julie , Cameron Sharon , Boydell Nicola
Published: July 2020

Background

Between 2017 and 2019, legislation was introduced in the UK that approved the home as a place for self-administration of misoprostol for early medical abortion. While research has shown that early medical abortion at home is as safe as in a clinical setting, women’s experiences in the UK in the light of this change have not yet been investigated. This qualitative research explored the experiences of women in one region of Scotland, UK who accessed early medical abortion with home self-administration of misoprostol.

Methods

Qualitative interviews were conducted with 20 women who had recently undergone early medical abortion (≤69 days' gestation) with home self-administration of misoprostol. The data were analysed thematically using an approach informed by the Framework analytic approach.

Results

Women appreciated the flexibility that home administration of misoprostol offered, including the opportunity to control the timing of the abortion. This was particularly important for women who sought not to disclose the abortion to others. Most women valued being in the comfort and privacy of the home when preparing for self-administration, although a small number highlighted some concerns about being at home. Most women reported that self-administration of misoprostol was straightforward; however, some expressed concerns around assessing whether their experiences were ‘normal’.

Conclusions

Women welcomed the opportunity for home self-administration of misoprostol. To further improve women’s early medical abortion experience we suggest that the legislation be amended so that women can self-administer in an appropriate non-clinical setting, not just their home.
Polymorphism in GSTM1 and GSTT1 genes influence DNA damage in personnel occupationally exposed to volatile anaesthetics (VA), from Peshawar, Pakistan
Authors: Khisroon Muhammad , Humayun Maleeha , Khan Ajmal , Farooqi Javeed , Humayun  , khan Jamal
Published: July 2020

Objectives

The objective of this study was to assess the influence of antioxidant gene GSTM1 and GSTT1 on DNA damage in personnel occupationally exposed to volatile anaesthetics (VA).

Methods

The study groups were composed of 50 exposed subjects (anaesthesia workers) and 49 controls. Blood samples were collected from both subjects. DNA damage was analysed through the comet assay technique. Biomarker genes GSTM1 and GSTT1 were inspected through PCR technique for polymorphism.

Results

The comet assay technique showed that the Total Comet Score (TCS) in exposed subjects was significantly higher (p=0.0001) than the control. Age and smoking had significant effects on TCS in the study groups (p<0.05). Duration of occupational exposure had significant positive correlation (r=0.755, p<0.001) with DNA damage. The null polymorphism in GSTM1 and GSTT1 gene showed a significant effect (p<0.001 and p<0.000) on the DNA damage.

Conclusions

The polymorphism in GSTM1 and GSTT1 gene significantly damage DNA in personnel occupationally exposed to VA.
Retrospective case series to identify the most common conditions seen ‘out‐of‐hours’ by first‐opinion equine veterinary practitioners
Authors: Bowden Adelle , Boynova Polina , Brennan Marnie Louise , England Gary C W , Mair Tim S , Furness Wendy A , Freeman Sarah L , Burford John H
Published: July 2020

Background

The study aim was to describe conditions seen ‘out‐of‐hours’ in equine practice.

Methods

This was a retrospective case series of first opinion ‘out‐of‐hours’ cases seen at two equine practices between 2011 and 2013. Data were retrieved on case presentation, diagnostic testing, treatment administered and outcome, and diseases categorised using a systems‐based coding system. A hierarchical logistic regression, formulated using a generalised linear model, was used to identify clinical variables associated with a binary outcome of ‘critical’ cases (required hospitalisation or euthanasia or died).

Results

Data from 2602 cases were analysed. The most common reasons for ‘out‐of‐hours’ visits were colic (35 per cent, n=923/2620), wounds (20 per cent, n=511/2620) and lameness (11 per cent, n=288/2,620). The majority of cases required a single treatment (58 per cent, n=1475/2550), 26 per cent (n=656/2550) needed multiple treatments and 13 per cent (n=339/2550) were euthanased. Eighteen per cent (n=480/2602) of cases had a critical outcome. Increased heart rate at primary presentation was associated with critical outcome in both practices (Practice A, OR 1.07 (95 per cent confidence interval 1.06 to 1.09), Practice B OR 1.08 (95 per cent confidence interval 1.07 to 1.09; p<0.001)).

Conclusion

Colic, wounds and lameness were the most common equine ‘out‐of‐hours’ conditions; 13 per cent of cases were euthanased. Further research is required into out‐of‐hours euthanasia decision‐making.
Providing information about triclabendazole resistance status influences farmers to change liver fluke control practices
Authors: Coyne Lucy Alice , Bellet Camille , Latham Sophia M , Williams Diana
Published: July 2020

Background

Reports of disease and production losses associated with Fasciola hepatica, the common liver fluke, have increased in recent years. Resistance to triclabendazole, one of the principal veterinary medicines used to prevent losses, has been reported and is now considered widespread in fluke endemic regions of the UK.

Methods

Thirteen farmers participated in a trial in 2013 and the triclabendazole resistance status was obtained for each farm. Based on these results, a knowledge exchange programme on fluke control was delivered to nearly 100 farmers in the region. In this follow‐up study, 11 farmers involved in the original trial, participated in semistructured in‐depth qualitative interviews in July 2017.

Results

Overall, participants identified benefits from participating in the 2013 trial, gaining information about triclabendazole resistance on their farms and knowledge about fluke control. The information on their farm's resistance status was a driver for changing their liver fluke control programmes. Factors such as habitual and repetitive behaviours, grazing restrictions due to agri‐environmental schemes, economic pressures and climate change were identified that could impede or prevent the adoption of new control strategies.

Conclusions

The study highlights the significance of resistance to triclabendazole and the impact of knowledge exchange programmes in changing liver fluke control practices.
Performance of highway embankments in the Arctic constructed under winter conditions
Authors: De Guzman Earl Marvin B. , Alfaro Marolo C. , Doré Guy , Arenson Lukas U. , Piamsalee Aron
Published: July 2020

There are uncertainties related to the mechanical behaviour of embankments where frozen soil is used as fill material and experiences natural thawing and settlements during the first thawing season following construction. Fill material of embankments in the Arctic is primarily sourced from locally available borrow sites that, in certain areas, are predominantly composed of fine till with high ground ice content. Side slope sloughing and fill cracking typically occur due to thawing of the frozen soil and development of localized thaw settlements under the embankment shoulders and side slopes. To assess the performance of a frozen fill embankment, test sections were constructed along the Inuvik–Tuktoyaktuk Highway in the Northwest Territories, Canada, and instrumented with temperature and displacement sensors. One test section was reinforced with layers of wicking woven geotextiles at its side slopes to primarily provide reinforcement against lateral movements and drainage during the thawing season. Field data show that the central and bottom portions of the embankment fill are still frozen while the thaw depth has increased at the toe. This paper presents the analysis and synthesis of the first 3 years of monitored performance of the embankment test sections following construction.
Capping dewatered oil sands fluid fine tailings with salvaged reclamation soils at varying depths to grow woody plants
Authors: Lalonde Ryan S. , Pinno Bradley D. , MacKenzie M. Derek , Utting Nicholas
Published: July 2020

Managing fluid fine tailings (FFT) present a major cause of industrial and environmental concerns in oil sands surface mining production. A potential management solution is to dewater and cap the FFT solids for use in land reclamation. A 16 wk greenhouse study was conducted to assess whether FFT centrifuge cake with caps of various reclamation soil mixes (forest floor mineral mix, peat mineral mix, and a mixture of both) and depths (0, 5, 10, and 20 cm) would support growth of trembling aspen (Populus tremuloides — native broadleaf tree) and beaked willow (Salix bebbiana — native broadleaf shrub). Beaked willow had a much greater survival rate (100%) when grown directly in FFT cake compared with trembling aspen (16.7%). Plants grown directly in FFT cake were negatively impacted by high water content, low nitrate supply rates, and high metal concentrations with beaked willow seedlings having 10 times higher foliar concentrations of Al, Cr, and Ti compared with any other treatments. Adding soil caps substantially increased aboveground biomass for both species, but differences among soil cap types and depths did not have as significant of an effect on plant growth. Results from this study show that capping FFT substantially improves woody plant growth, and S. bebbiana and P. tremuloides are potentially suitable species for tailings reclamation.
Black hole evaporation in Hořava–Lifshitz gravity
Authors: Xu Hao , Ong Yen Chin
Published: July 2020

Hořava–Lifshitz (HL) gravity was formulated in hope of solving the non-renormalization problem in Einstein gravity and the ghost problem in higher derivative gravity theories by violating Lorentz invariance. In this work we consider the spherically symmetric neutral AdS black hole evaporation process in HL gravity in various spacetime dimensions d, and with detailed balance violation parameter $$0\leqslant \epsilon ^2\leqslant 1$$0⩽ϵ2⩽1. We find that the lifetime of the black holes under Hawking evaporation is dimensional dependent, with $$d=4,5$$d=4,5 behave differently from $$d\geqslant 6$$d⩾6. For the case of $$\epsilon =0$$ϵ=0, in $$d=4,5$$d=4,5, the black hole admits zero temperature state, and the lifetime of the black hole is always infinite. This phenomenon obeys the third law of black hole thermodynamics, and implies that the black holes become an effective remnant towards the end of the evaporation. As $$d\geqslant 6$$d⩾6, however, the lifetime of black hole does not diverge with any initial black hole mass, and it is bounded by a time of the order of $$\ell ^{d-1}$$ℓd-1, similar to the case of Schwarzschild-AdS in Einstein gravity (which corresponds to $$\epsilon ^2=1$$ϵ2=1), though for the latter this holds for all $$d\geqslant 4$$d⩾4. The case of $$0<\epsilon ^2<1$$0<ϵ2<1 is also qualitatively similar with $$\epsilon =0$$ϵ=0.
Multi-Frame Super-Resolution Reconstruction Algorithm of Optical Remote Sensing Images Based on Double Regularization Terms and Unsupervised Learning
Authors: Zhao Xiaodong , Zhang Xunying
Published: July 2020

High-resolution images have always been in urgent need in the fields of surveying, mapping, military and civilian. In this paper, first, based on anisotropic nonlinear diffusion tensor, a diffusion tensor regularization term which can make full use of direction selection smoothing property was constructed. Based on the improved gradient vector field (GVF), a regularization term which can constrain the continuity of gradient vectors for high-resolution and low-resolution images was constructed. On the basis of these, a multi-frame super-resolution reconstruction algorithm based on double regularization terms was proposed and verified by simulation. Second, combining PCA with adaptive dictionary learning, two constraints of reconstruction regularity based on improved nonlocal means and kernel regression were proposed for experimental verification, and an improved K-means clustering algorithm for initial centre selection of spatial characteristic measure clustering was proposed to enhance the stability of the algorithm. Then high-resolution image generated by learning method was used as the initial input of multi-frame reconstruction of optical remote sensing images. The experimental results show that the reconstruction algorithm based on partial differential equation and unsupervised learning achieves both subjective and objective results for the realization of super-resolution reconstruction of optical remote sensing images.
A 6.4-GS/s 10-b Time-Interleaved SAR ADC with Time-Skew Immune Sampling Network in 28-nm CMOS
Authors: Ding Ning , Mu Yusong , Guo Yuping , Chen Teng , Chang Yuchun
Published: July 2020

This paper presents a 6.4-GS/s 16-way 10-bit time-interleaved (TI) SAR ADC for wideband wireless applications. A two-stage master–slave hierarchical sampling network, which is immune to the time skew of multi-phase clocks, is introduced to avoid the time-skew calibration for design simplicity and hardware efficiency. To perform low distortion and fast sampling at acceptable power consumption, a linearity- and energy efficiency-improved track-and-hold (T&H) buffer with current-feedback compensation scheme is proposed. Accompanied by its low-output-impedance feature, the buffer obtains adequate bandwidth which can cover the entire ADC Nyquist sampling range. Moreover, the split capacitor DAC combined with a novel nonbinary algorithm is adopted in single-channel ADC, enabling a shorter DAC settling time as well as less switching energy. Capacitor mismatch effect with related design trade-off is discussed and behavior models are built to evaluate the effect of capacitor mismatch on ENOB. An asynchronous self-triggered SAR logic is designed and optimized to minimize the delay on logic paths to match up the acceleration on DAC and comparator. With these proposed techniques, the 10-b sub-ADC achieves a 400-MHz conversion rate with only 3.5-mW power consumption. The circuit is designed and simulated in TSMC 28 HPC process and the results show that the overall ADC achieves 54.6-dB SNDR and 58.1-dB SFDR at Nyquist input while consuming 127-mW power from 1-V/1.5-V supply and achieving a Walden FoM of 45[Formula: see text]fJ/conv-step.
Zero-cycles on double EPW sextics
Authors: Laterveer Robert , Vial Charles
Published: July 2020

The Chow rings of hyperKähler varieties are conjectured to have a particularly rich structure. In this paper, we focus on the locally complete family of double EPW sextics and establish some properties of their Chow rings. First, we prove a Beauville–Voisin type theorem for zero-cycles on double EPW sextics; precisely, we show that the codimension-4 part of the subring of the Chow ring of a double EPW sextic generated by divisors, the Chern classes and codimension-2 cycles invariant under the anti-symplectic covering involution has rank one. Second, for double EPW sextics birational to the Hilbert square of a K3 surface, we show that the action of the anti-symplectic involution on the Chow group of zero-cycles commutes with the Fourier decomposition of Shen–Vial.
Modeling Cascading Failures in Stock Markets by a Pretopological Framework
Authors: Nguyen Ngoc Kim Khanh , Bui Marc
Published: July 2020

We introduce a computational framework, namely, a pretopological construct, for mining stock prices’ time series in order to expand a set of stocks by adding other stocks whose average correlations with the set are above a threshold. We increase the threshold with the set’s size to verify group impact in financial crises. This approach is tested by a consecutive expansion process started from a stock of Merrill Lynch & Co., and a consecutive contraction process of the rest. The test’s results and the comparison to graph theory show that our model and pretopology theory are helpful to study stock markets.
Updating the Frame Problem for AI Research
Authors: Miracchi Lisa
Published: July 2020

The Frame Problem is the problem of how to design a machine to use information so as to behave competently, with respect to the kinds of tasks a genuinely intelligent agent can reliably, effectively perform. I will argue that the way the Frame Problem is standardly interpreted, and so the strategies considered for attempting to solve it, must be updated. We must replace overly simplistic and reductionist assumptions with more sophisticated and plausible ones. In particular, the standard interpretation assumes that mental processes are identical to certain kinds of computational processes, and so solving the Frame Problem is a matter of finding a computational architecture that can effectively represent relations of semantic relevance. Instead, we must take seriously the possibility that the way in which intelligent agents use information is inherently different. Whereas intelligent agents are plausibly genuinely causally sensitive to semantic properties as such (to what they perceive, desire, believe intend, etc.), computational systems can only be causally sensitive to the formal features that represent these properties. Indeed, it is this very substitution of formal generalizations for genuinely semantic ones that is responsible for the way current AI systems are brittle, inflexible, and highly specialized. What we need is a more sophisticated way of investigating the relationship between computational information processing and genuinely semantic information use. I apply the generative methodology I have developed elsewhere for cognitive science and AI research to show how the Frame Problem can be appropriately updated.
Upcoming SIGWEB supported conferences
Authors: Roßner Daniel
Published: July 2020

The Special Interest Group on Hypertext and the Web, SIGWEB was created in 1989 to support the community participating in the annual ACM Hypertext Conference. Now in its third decade, SIGWEB has grown considerably and now sponsors seven annual conferences of different sizes and covering a wide range of topics. SIGWEB supports several specialized conferences, short courses, and workshops, as well as the Annual Hypertext Conference. SIGWEB sponsored conferences focus on timely topics in applied and computational hypertext and Web disciplines and provide a place for members and the entire applied Hypermedia and Web community to exchange ideas and to meet with and expand their network of colleagues. In this article, we provide a brief overview of SIGWEB sponsored conferences, in addition to events that are in cooperation with SIGWEB.

Due to the current Corona crisis, many event organizers opted for an online conference format. These conferences are marked accordingly.
EDF scheduling of real-time tasks on multiple cores
Authors: Abeni Luca , Cucinotta Tommaso
Published: July 2020

This paper presents a novel migration algorithm for real-time tasks on multicore systems, based on the idea of migrating tasks only when strictly needed to respect their temporal constraints and a combination of this new algorithm with EDF scheduling. This new "adaptive migration" algorithm is evaluated through an extensive set of simulations showing good performance when compared with global or partitioned EDF: our results highlight that it provides a worst-case utilisation bound similar to partitioned EDF for hard real-time tasks and an empirical tardiness bound (like global EDF) for soft real-time tasks. Therefore, the proposed scheduler is effective for dealing with both hard and soft real-time workloads.
An adaptive, utilization-based approach to schedule real-time tasks for ARM big.LITTLE architectures
Authors: Mascitti Agostino , Cucinotta Tommaso , Marinoni Mauro
Published: July 2020

ARM big.LITTLE architectures are spreading more and more in the mobile world thanks to their power-saving capabilities due to the use of two ISA-compatible islands, one focusing on energy efficiency and the other one on computational power. This architecture makes the problem of energy-aware task scheduling particularly challenging, due to the number of variables to take into account and the need for having lightweight mechanisms that can be readily computed in an operating system kernel scheduler.

This paper presents a novel task scheduler for big.LITTLE platforms, combining the well-known Constant Bandwidth Server algorithm with a power-aware per-job migration policy. This achieves real-time adaptation of the CPU islands' frequencies based on the individual cores' overall utilization, as available in the scheduler thanks to the use of the resource reservation paradigm. Preliminary results obtained by simulations based on modifications to the open-source RTSim tool show that the proposed technique is able to achieve interesting performance/energy trade-offs.
Earl
Authors: Reif Stefan , Raffeck Phillip , Janker Heiko , Gerhorst Luis , Hönig Timo , Schröder-Preikschat Wolfgang
Published: July 2020

As system complexity grows, embedded operating systems increasingly face the challenge to adhere to various non-functional constraints, such as response times and power limits. These requirements sometimes contradict and, often, no solution satisfies all constraints under all conditions. Changes in environmental conditions, application-level requirements, and user response time expectation hence demand for system-wide adaptions to resource management. We find that process synchronization constitutes a simple yet effective leverage point to balance between timing-related and energy-related constraints. This paper presents Earl, an implementation of reconfigurable locks in Linux that enables seamless transitions between high-performance and low-power operating modes.
An Interrupted Sampling Scattered Wave Deception Jamming Method against Three-Channel SAR GMTI
Authors: Chang Xin , Dong Chunxi , Weichen Gao , Zhao Yan
Published: July 2020

An important problem is how to generate false moving targets, whose relocated azimuth position is similar to that of real moving targets. To solve this problem, an interrupted sampling scattered wave deception jamming method against three-channel synthetic aperture radar ground moving target indication (SAR GMTI) is proposed. A stationary jammer uses a controllable jammer antenna to generate verisimilar moving targets by controlling velocity and initial position of jammer beam footprint. The antenna sampled moves along the different tracks. For each track, the slant history of jamming signal is changed varying with different pulse recurrence intervals (PRI), and the movement of the footprint will introduce a Doppler frequency in jamming the signal. By analyzing parameters’ difference between echoes and jamming signal, the velocity and the initial position of the footprint will be calculated, and then the verisimilar false targets are generated. The effectiveness of the method is verified by simulation experiments.
Pulmonary Vein Occlusion and Lung Infarction after Radiofrequency Ablation of Atrial Fibrillation
Authors: Al Fori Julyan , Al Belushi Maryam , Al Shuraiqi Mohammed , Al Mohanny Ghalia , Al Umairi Rashid , Al Busaidi Nasser
Published: July 2020

Background. Pulmonary vein (PV) radiofrequency ablation (RFA) is an effective technique for a selected group of patients with atrial fibrillation (AF) refractory to antiarrhythmic drugs (Alfudhili et al., 2017). However, pulmonary vein occlusion is a potentially rare, sometimes severe, complication which may present clinically as nonspecific respiratory symptoms, signifying pulmonary vein stenosis, that are often underrecognized or misdiagnosed, leading to progression of the low-grade stenosis to complete occlusion if not treated with timely intervention (Alfudhili et al., 2017). Case Presentation. We report the first case of haemoptysis, three months postradiofrequency ablation (i.e., late complication) secondary to pulmonary vein occlusion that was diagnosed by computed tomography angiogram (CTA), which showed occlusion of 2 out of 4 native pulmonary veins. Conclusion. The cause of haemoptysis in this patient was pulmonary vein occlusion, secondary to radiofrequency ablation, as demonstrated in the CTA.
Adsorption Ability for Toxic Chromium (VI) Ions in Aqueous Solution of Some Modified Oyster Shell Types
Authors: Nguyen Thuy Chinh , Nguyen Xuan Thai , Tran Do Mai Trang , Vu Quoc Trung , Nguyen Van Hai , Nguyen Duy Trinh , Do Minh Thanh , Nguyen Thi Len , Ly Thi Ngoc Lien , Thai Hoang
Published: July 2020

In this paper, the chromium, Cr (VI), ion adsorption ability of oyster shell samples collected from two sea regions in Vietnam (Phu Yen province and Quang Ninh province) was investigated and compared. The oyster shell samples were calcined at different temperatures and denatured by using ethylenediaminetetraacetic acid (EDTA). The Cr (VI) ion adsorption ability of the prismatic (PP) and nacreous (NP) shell layers of oysters was also evaluated. The characteristics of oyster shell samples before and after treatment were determined by using analysis methods including XRD, IR, BET, UV-Vis, and FESEM. The Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich models and fit statistic equations were used to study the adsorption isotherms of Cr (VI) ion adsorption by oyster shells. The Cr (VI) ions adsorption kinetic has been set up using four reaction models consisting of first-order, pseudo-first-order, second-order, and pseudo-second-order reaction models. Effects of experimental factors on the Cr (VI) ion adsorption process using oyster shells were also investigated and discussed in this work.
Study of Dynamical Behavior and Stability of Iterative Methods for Nonlinear Equation with Applications in Engineering
Authors: Rafiq Naila , Akram Saima , Mir Nazir Ahmad , Shams Mudassir
Published: July 2020

In this article, we first construct a family of optimal 2-step iterative methods for finding a single root of the nonlinear equation using the procedure of weight function. We then extend these methods for determining all roots simultaneously. Convergence analysis is presented for both cases to show that the order of convergence is 4 in case of the single-root finding method and is 6 for simultaneous determination of all distinct as well as multiple roots of a nonlinear equation. The dynamical behavior is presented to analyze the stability of fixed and critical points of the rational operator of one-point iterative methods. The computational cost, basins of attraction, efficiency, log of the residual, and numerical test examples show that the newly constructed methods are more efficient as compared with the existing methods in the literature.
Identification and Validation of an Energy Metabolism‐Related lncRNA‐mRNA Signature for Lower‐Grade Glioma
Authors: Zhao Jingwei , Wang Le , Wei Bo
Published: July 2020

Energy metabolic processes play important roles for tumor malignancy, indicating that related protein‐coding genes and regulatory upstream genes (such as long noncoding RNAs (lncRNAs)) may represent potential biomarkers for prognostic prediction. This study will develop a new energy metabolism‐related lncRNA‐mRNA prognostic signature for lower‐grade glioma (LGG) patients. A GSE4290 dataset obtained from Gene Expression Omnibus was used for screening the differentially expressed genes (DEGs) and lncRNAs (DELs). The Cancer Genome Atlas (TCGA) dataset was used as the prognosis training set, while the Chinese Glioma Genome Atlas (CGGA) was for the validation set. Energy metabolism‐related genes were collected from the Molecular Signatures Database (MsigDB), and a coexpression network was established between energy metabolism‐related DEGs and DELs to identify energy metabolism‐related DELs. Least absolute shrinkage and selection operator (LASSO) analysis was performed to filter the prognostic signature which underwent survival analysis and nomogram construction. A total of 1613 DEGs and 37 DELs were identified between LGG and normal brain tissues. One hundred and ten DEGs were overlapped with energy metabolism‐related genes. Twenty‐seven DELs could coexpress with 67 metabolism‐related DEGs. LASSO regression analysis showed that 9 genes in the coexpression network were the optimal signature and used to construct the risk score. Kaplan‐Meier curve analysis showed that patients with a high risk score had significantly worse OS than those with a low risk score (TCGA: HR = 3.192, 95%CI = 2.182‐4.670; CGGA: HR = 1.922, 95%CI = 1.431‐2.583). The predictive accuracy of the risk score was also high according to the AUC of the ROC curve (TCGA: 0.827; CGGA: 0.806). Multivariate Cox regression analyses revealed age, IDH1 mutation, and risk score as independent prognostic factors, and thus, a prognostic nomogram was established based on these three variables. The excellent prognostic performance of the nomogram was confirmed by calibration and discrimination analyses. In conclusion, our findings provided a new biomarker for the stratification of LGG patients with poor prognosis.
Adaptive Finite-Time Congestion Control for Uncertain TCP/AQM Network with Unknown Hysteresis
Authors: Zheng Weimin , Li Yanxin , Jing Xiaowen , Liu Shangkun
Published: July 2020

The issue of adaptive practical finite-time (FT) congestion control for the transmission control protocol/active queue management (TCP/AQM) network with unknown hysteresis and external disturbance is considered in this paper. A finite-time congestion controller is designed by the backstepping technique and the adaptive neural control method. This controller guarantees that the queue length tracks the desired queue in finite-time, and it is semiglobally practical finite-time stable (SGPFS) for all the signals of the closed-loop system. At last, the simulation results show that the control strategy is effective.
Sorting Data via a Look-Up-Table Neural Network and Self-Regulating Index
Authors: Zhao Ying , Hu Dongli , Huang Dongxia , Liu You , Yang Zitong , Mao Lei , Liu Chao , Zhou Fangfang
Published: July 2020

The so-called learned sorting, which was first proposed by Google, achieves data sorting by predicting the placement positions of unsorted data elements in a sorted sequence based on machine learning models. Learned sorting pioneers a new generation of sorting algorithms and shows a great potential because of a theoretical time complexity ON and easy access to hardware-driven accelerating approaches. However, learned sorting has two problems: controlling the monotonicity and boundedness of the predicted placement positions and dealing with placement conflicts of repetitive elements. In this paper, a new learned sorting algorithm named LS is proposed. We integrate a back propagation neural network with the technique of look-up-table in LS to guarantee the monotonicity and boundedness of the predicted placement positions. We design a data structure called the self-regulating index in LS to tentatively store and duly update placement positions for eliminating potential placement conflicts. Results of three controlled experiments demonstrate that LS can effectively control the monotonicity and boundedness, achieve a better time consumption than quick sort and Google’s learned sorting, and present an excellent stability when the data size or the number of repetitive elements increases.
Undernutrition and Mortality among Adult Tuberculosis Patients in Addis Ababa, Ethiopia
Authors: Seid Getachew , Ayele Marta
Published: July 2020

Background. In developing countries, there are several adult tuberculosis (TB) patients suffering from profound undernutrition. Undernutrition is a significant risk factor for developing tuberculosis. In the world, TB is one of the top ten and leading causes of death. To appropriately intervene death of adult TB patients, it is crucial to understand the magnitude of undernutrition and its associated factors among them. The study assessed undernutrition and mortality among adult tuberculosis patients in Addis Ababa, Ethiopia. Methods. Institutional-based retrospective study was conducted in Addis Ababa, Ethiopia, from January 2019 to August 2019. The total sample size of the study was 284. The source populations were TB patients who have followed up for TB treatment at public health facilities of Addis Ababa. The sample size was allocated to the selected health facilities proportional to their size, and study subjects were enrolled to the study during the study period. Data were collected by a structured data sheet from the selected health center registration book. Data were entered into Epi Data software and analyzed by using SPSS version 20. Descriptive statistical methods were used to summarize the sociodemographic characteristics of the study participants. Survival curves were generated using the Kaplan–Meier method for all TB patients. Result. A total of 284 study participants were included in the study. It was found that 46.8% of the study population have undernutrition (BMI <18.5 kg/m2) at the time of registration for treatment. Out of undernourished patients, 54 (19.0%) had severe malnutrition and 78 (27.5%) had moderate undernutrition. At the end of the two-month intensive treatment period, the under nutrition prevalence declined to 38.7%. Of the 284 patients, 17 (6.0%) died before completing anti-TB treatment. Three quarters of all forms of TB deaths occurred within 57 days after the start of anti-TB treatment. The proportion of deaths by nutritional status at treatment initiation among normal, moderate acute malnutrition, and severe acute malnutrition TB patients was 3.1%, 8.9%, and 16.3%, respectively. Conclusion. Almost half of the TB patients were undernourished at the start of anti-TB treatment based on BMI. From the malnourished, less than 20% of the participants gained weight and moved to normal weight at the end of the two-month intensive treatment period. The high death rate was reported among severely malnourished tuberculosis patients, but it needs a larger study to further understand predictors. To enhance the increment of nutritional status during treatment, the government should give attention to support nutritional supplements for TB patients.