bluuebunny/crossref_metadata_2025 huggingface dataset:
The Modifications of Electronic and Optical Properties of Bulk Molybdenum Disulfide by Oxygen Substitution
Authors: Charvia Louis , Muhammady Shibghatullah , Darma Yudi
Published: September 2019

We study the electronic and optical properties of bulk MoS2 and MoSO systems using the plane-wave method within the generalized gradient approximation. The structural properties show that the O substitution at S sites tunes the z-axis Wyckoff positions of all atoms and the bond angles. The electronic band structures show that the substitution tunes the conduction band minimum at 0.8 Σ to M and significantly promotes more localized valence states compared to that of MoS2 system. The localization, mainly applying to Mo 4d and S 3p states, is more pronounced above −4 eV. Below −4 eV, O 2p states are dominant indicating that they are more stable than S 3p states. However, the substitution slightly increases the indirect and direct (K → K) bandgap of MoS2 system. From the optical properties, both systems show the strong optical dichroism. By means of the substitution, the σ1 width significantly enhances, while the plasmonic-state energy levels decrease. Our result emphasizes that the O substitution significantly tunes the electronic and optical properties of bulk MoS2 system.
Study on Graphene Oxide (GO) Supernatant Dilution to the Optical and Electrical Properties of TCF Based-reduced Graphene Oxide (RGO) Films
Authors: Rahmawati Dina , Aimon Akfiny Hasdi , Iskandar Ferry , Wibowo Arie , Khairurrijal Khairurrijal
Published: September 2019

Graphene is a potential material to replace indium tin oxide (ITO) and fluorine tin oxide (FTO) as a transparent conductive films (TCF) due to its high conductivity and transparency. In this study, fabrication of graphene-based TCF was carried out by means of the drop-casting method, with graphite oxide as the raw material. The graphene oxide (GO) was diluted by adding 1, 3, 5, and 7 ml of distilled (DI) water. The sample was also heat treated to ensure complete reduction process. The deposited films were characterized using UV-Vis spectroscopy and I-V to investigate their optical and electrical properties. Based on the measurement results, sample with 3 ml DI water addition gives transparency and sheet resistance (Rs) of 41.01 % and 9.43 kΩ/sq, respectively. This material has a great potential to be applied as the optoelectronics material.
Fabrication of Flexible Graphite Film Using a Mechanical Method and Its Application in Tio2/Graphite Solar Cell as a Flexible Counter Electrode
Authors: Rahman Dui Yanto , Utami Fisca Dian , Margaretta Desyana Olenka , Sustini Euis , Abdullah Mikrajuddin
Published: September 2019

We have successfully fabricated solar cell using flexible counter electrode of graphite powder. TiO2 / graphite suspension was simply poured onto heated Fluorine Tin Oxide (FTO) substrate and kept heated at 200°C for 2 hours. PVA.LiOH polymer electrolyte was employed as a positive charge transfer medium. The counter electrode was made of graphite powder which is manually deposited on transparent plastic using tube-shaped metal which its surface covered with tissue of 2 mm thick. Graphite powder was deposited by straight motion of 20 movements for one coating or one layer. The same activity was repeated on the stacked film to increase the conductivity of the film. Resistivity and transmittance measurement of the film was performed by four-point probe method and UV-Vis equipment respectively. The film thickness and 2-D porosity were measured using an electronic microscope and ImageJ software orderly. The film resistivity and transmittance gradually decreased with the increase of coating number and reached the resistivity of 0.35 Ω.cm and transmittance of 5% for 40 times of coating. At the same time, the film thickness was saturated at the 30 times coating and reached the thickness of 9.4 μm. The film 2-D porosity which indicated how well the surface of the film covered the graphite also decreased to reach the film porosity of 18%. The most conductive film (40 times coating) was used as a flexible counter electrode in TiO2/graphite solar cell. The efficiency of this structure was 0.4 %, a reasonable efficiency achievement for a cheap material and easy method used.
Flexural Strength of Hybrid Mendong – C-glass/Epoxy Thermoseting Composites
Authors: Banowati L , Iskandar T K
Published: September 2019

Hybrid composite materials are those composites which have a combination of two or more reinforcement fibre in order to better mechanical properties. This paper concerns with development of hybrid composite materials using mendong and C-glass as the reinforcement and epoxy bakellite EPR 174 resin as the matrix, using hand lamination process. The mendong fibre was treated with alkali (NaOH). Hybrid mendong – C-glass/epoxy composite specimens were arranged to make a unidirectional (0°), bidirectional (0°/90°) and bidirectional (± 45°) fibre orientations with a 50% v/v fibre fraction content. The specimens were then tested using flexural tests, and the results were analyzed using two parameters Weibull distribution. The result shows that the flexural strength of hybrid mendong – C-glass/epoxy composites with a unidirectional (0°) is higher than other fiber orientations.
Zeolites as Adsorbent Materials for Decolorization of Crude Terpineol
Authors: Indarto A , Putra I A , Riyano  , Noersalim S , Hartanto Y , Handojo L
Published: September 2019

Zeolites are microporous crystalline aluminosilicates extensively used as adsorbents, catalysts, and ion exchange beds. The adsorption property of zeolite is expected to be applied as a decolorization agent for terpineol. Terpineol is an alcohol compound derived from turpentine oil and widely used as an active ingredient for disinfectants, cleansers, perfumes, and pharmaceutical purposes. Industrial-scale of terpineol production used two stages of reaction: the first stage is hydration of turpentine into terpin hydrate and the second stage is dehydration of terpin hydrate to terpineol. However, as terpin hydrate is easily oxidized, the product color will change from clear into dark solution and make the price of product cheaper. This study aims to increase terpineol selling price by removing unreacted terpin hydrate (decolorization) from crude terpineol. Zeolite is the main absorbent used in this study along with other similar materials i.e. activated carbon and silica gel. Performances of the adsorbent are indicated by its adsorption capacity and color clarity analysis. The results would be analyzed using GC-MS. Based on the experiment, it can be concluded that the best adsorbent is zeolite activated by acetic acid with 8-15 mg/g adsorption capacity and producing a terpineol purity of 83.5%. This activated zeolite was able to remove terpin hydrate from 9.41% to 0% and other impurities from 14.06% to 6.78%.
Characterization of Nano Chitosan-Cucumber Suri (Cucumis melo L.) Seeds with Sodium Tripolyphosphate as Crosslinker
Authors: Vifta Rissa Laila , Luhurningtyas Fania Putri , Fajarwati Febi Indah
Published: September 2019

Cucumber suri (Cucumis melo L.) is one of natural materials which has many bioactivities, such as antioxidant, antifungal, antibacterial, anti-cholesterol, antidiabetic, and several other activities. Eventough, Cucumber suri (Cucumis melo L.) has a fairly low flavonoid content. In addition, bioactive compounds in cucumber suri seeds tend to be difficult to dissolve in water, unstable to pH, and even have a low bioavailability. Nanoparticles can be used to increase the activity of natural materials by using chitosan and sodium tripolyphosphate as crosslinking agents. This study aims to determine the characteristics of nano chitosan-cucumber suri seeds (Cucumis melo L.). First, Cucumber Suri seeds weas previously extracted using maceration method and identified theirs bioactive compounds. And then, Cucumber Suri seed extract was encapsulated with Chitosan: STPP (5: 1). Characterization test was carried out using UV-Vis Spectrophotometry, Infrared Spectrophotometry, and Particle Size Analyzer (PSA). The encapsulation process of Cucumber Suri seed extract produces a clear, homogeneous and stable supernatant. The values of characterization with UV-Vis Spectrophotometry in 0 to 60 minutes was >90%, that indicated nanosized particleswas succefully formed. The IR characterization values indicate a shift in the nano chitosan-cucumber suri seeds wavelength compare with chitosan. The shift of –OH stretching vibration at wavelength 3403 cm−1 and stretching vibration of C=O in 1642 cm−1 showed there was an interaction between chitosan and Cucumber Suri seed extract. Analysis using Particle Size Analyzer (PSA) showed that chitosan-cucumber suri seeds had a normal polydispersion index (PI) of 0.677 and average particle diameter size was 360 nm.
Oka complements of countable sets and nonelliptic Oka manifolds
Authors: Kusakabe Yuta
Published: September 2019

We study the Oka properties of complements of closed countable sets in

C

n

 
(
n
>
1
)

\mathbb {C}^{n}\ (n>1)

which are not necessarily discrete. Our main result states that every tame closed countable set in

C

n

 
(
n
>
1
)

\mathbb {C}^{n}\ (n>1)

with a discrete derived set has an Oka complement. As an application, we obtain nonelliptic Oka manifolds which negatively answer a long-standing question of Gromov. Moreover, we show that these examples are not even weakly subelliptic. It is also proved that every finite set in a Hopf manifold has an Oka complement and an Oka blowup.
Spherically symmetric solutions of the multidimensional, compressible, isentropic Euler equations
Authors: Schrecker Matthew
Published: September 2019

In this paper, we prove the existence of finite-energy weak solutions to the compressible, isentropic Euler equations given arbitrary spherically symmetric initial data of finite energy. In particular, we show that the solutions to the spherically symmetric Euler equations obtained in recent works by Chen and Perepelitsa and Chen and Schrecker are weak solutions of the multidimensional, compressible Euler equations. This follows from new uniform estimates made on artificial viscosity approximations up to the origin, removing previous restrictions on admissible test functions and ruling out formation of an artificial boundary layer at the origin. The uniform estimates may be of independent interest concerning the possible rate of blowup of density and velocity at the origin for spherically symmetric flows.
Flow equivalence of G-SFTs
Authors: Boyle Mike , Carlsen Toke , Eilers Søren
Published: September 2019

In this paper, a

G
G

-shift of finite type (

G
G

-SFT) is a shift of finite type together with a free continuous shift-commuting action by a finite group

G
G

. We reduce the classification of

G
G

-SFTs up to equivariant flow equivalence to an algebraic classification of a class of poset-blocked matrices over the integral group ring of

G
G

. For a special case of two irreducible components with

G
=

Z

2

G=\mathbb {Z}_2

, we compute explicit complete invariants. We relate our matrix structures to the Adler-Kitchens-Marcus group actions approach. We give examples of

G
G

-SFT applications, including a new connection to involutions of cellular automata.
A quantitative screen for metabolic enzyme structures reveals patterns of assembly across the yeast metabolic network
Authors: Noree Chalongrat , Begovich Kyle , Samilo Dane , Broyer Risa , Monfort Elena , Wilhelm James E.
Published: September 2019

Despite the proliferation of proteins that can form filaments or phase-separated condensates, it remains unclear how this behavior is distributed over biological networks. We have found that 60 of the 440 yeast metabolic enzymes robustly form structures, including 10 that assemble within mitochondria. Additionally, the ability to assemble is enriched at branch points on several metabolic pathways. The assembly of enzymes at the first branch point in de novo purine biosynthesis is coordinated, hierarchical, and based on their position within the pathway, while the enzymes at the second branch point are recruited to RNA stress granules. Consistent with distinct classes of structures being deployed at different control points in a pathway, we find that the first enzyme in the pathway, PRPP synthetase, forms evolutionarily conserved filaments that are sequestered in the nucleus in higher eukaryotes. These findings provide a roadmap for identifying additional conserved features of metabolic regulation by condensates/filaments.
Effects of the microtubule nucleator Mto1 on chromosomal movement, DNA repair, and sister chromatid cohesion in fission yeast
Authors: Zhurinsky Jacob , Salas-Pino Silvia , Iglesias-Romero Ana B. , Torres-Mendez Antonio , Knapp Benjamin , Flor-Parra Ignacio , Wang Jiyong , Bao Kehan , Jia Songtao , Chang Fred , Daga Rafael R.
Published: September 2019

Although the function of microtubules (MTs) in chromosomal segregation during mitosis is well characterized, much less is known about the role of MTs in chromosomal functions during interphase. In the fission yeast Schizosaccharomyces pombe, dynamic cytoplasmic MT bundles move chromosomes in an oscillatory manner during interphase via linkages through the nuclear envelope (NE) at the spindle pole body (SPB) and other sites. Mto1 is a cytoplasmic factor that mediates the nucleation and attachment of cytoplasmic MTs to the nucleus. Here, we test the function of these cytoplasmic MTs and Mto1 on DNA repair and recombination during interphase. We find that mto1Δ cells exhibit defects in DNA repair and homologous recombination (HR) and abnormal DNA repair factory dynamics. In these cells, sister chromatids are not properly paired, and binding of Rad21 cohesin subunit along chromosomal arms is reduced. Our findings suggest a model in which cytoplasmic MTs and Mto1 facilitate efficient DNA repair and HR by promoting dynamic chromosomal organization and cohesion in the nucleus.
FAP57/WDR65 targets assembly of a subset of inner arm dyneins and connects to regulatory hubs in cilia
Authors: Lin Jianfeng , Le Thuc Vy , Augspurger Katherine , Tritschler Douglas , Bower Raqual , Fu Gang , Perrone Catherine , O’Toole Eileen T. , Mills Kristyn VanderWaal , Dymek Erin , Smith Elizabeth , Nicastro Daniela , Porter Mary E.
Published: September 2019

Ciliary motility depends on both the precise spatial organization of multiple dynein motors within the 96 nm axonemal repeat and the highly coordinated interactions between different dyneins and regulatory complexes located at the base of the radial spokes. Mutations in genes encoding cytoplasmic assembly factors, intraflagellar transport factors, docking proteins, dynein subunits, and associated regulatory proteins can all lead to defects in dynein assembly and ciliary motility. Significant progress has been made in the identification of dynein subunits and extrinsic factors required for preassembly of dynein complexes in the cytoplasm, but less is known about the docking factors that specify the unique binding sites for the different dynein isoforms on the surface of the doublet microtubules. We have used insertional mutagenesis to identify a new locus, IDA8/BOP2, required for targeting the assembly of a subset of inner dynein arms (IDAs) to a specific location in the 96 nm repeat. IDA8 encodes flagellar-associated polypeptide (FAP)57/WDR65, a highly conserved WD repeat, coiled coil domain protein. Using high resolution proteomic and structural approaches, we find that FAP57 forms a discrete complex. Cryo-electron tomography coupled with epitope tagging and gold labeling reveal that FAP57 forms an extended structure that interconnects multiple IDAs and regulatory complexes.
An Electronic Strategy for Eliminating Unnecessary Duplicate Genetic Testing
Authors: Riley Jacquelyn D , Stanley Glenn , Wyllie Robert , Burt Holly L , Horwitz Sandra B , Cooper Donna D , Procop Gary W
Published: September 2019

Objectives

To determine the impact of an electronic intervention designed to block duplicate constitutional genetic tests.

Methods

We constructed, implemented, and studied an electronic intervention that stopped duplicate genetic tests. The activation frequency, types of tests affected, and cost savings achieved with this intervention were determined. The frequency and justification of override requests were also studied.

Results

This intervention stopped 710 unnecessary duplicate genetic tests over a 3-year period and saved $98,596. The tests with the highest numbers of alerts were those used for screening presurgical or transplant patients and were commonly part of an order set or test panel. Most override requests were justified because of the lack of exclusion codes in the initial programming.

Conclusions

Electronic interventions that stop duplicate genetic testing, if properly constructed, can reduce waste, save health care dollars, and facilitate patient care by directing the provider to a test that has already been performed.

1.Duplicate molecular genetic testing, although generally unnecessary, occurs due to challenges in locating previous results.

2.Clinical decision support at order entry alerts providers to previous genetic test results and restricts repeat orders.

3.This Once-in-a-Lifetime electronic intervention supports a value-based health care model by reducing unnecessary genetic testing and associated costs.
Development and Initial Testing of a Modified UroVysion-Based Fluorescence In Situ Hybridization Score for Prediction of Progression in Bladder Cancer
Authors: Kocsmár Ildikó , Pajor Gábor , Gyöngyösi Benedek , Székely Eszter , Varga Márton , Kocsmár Éva , Kenessey István , Beöthe Tamás , Süle Norbert , Majoros Attila , Szendrői Attila , Nyírády Péter , Kiss András , Riesz Péter , Lotz Gábor
Published: September 2019

Objectives

Our aim was to predict progression of non-muscle-invasive bladder urothelial carcinomas (NMIUCs) into muscle-invasive disease by assessing cytogenetic abnormality of tumors with a new UroVysion scoring system.

Methods

Seventy-five bladder cancer cases (including 57 NMIUCs) were classified according to the quantitatively assessed degree of UroVysion-detected chromosomal abnormalities into urine fluorescence in situ hybridization score (UFS) groups: UFS I, II, and III. Cox time-to-event, Kaplan-Meier, and C-statistics analyses were performed.

Results

UFS proved to be an independent prognostic factor of progression-free survival (PFS) and time to progression (TTP). NMIUCs with UFS III had a 34.05-fold increased hazard for progression to muscle-invasive cancer (TTP; 95% confidence interval, 5.841-198.5; P < .001) in comparison with UFS I to II cases. The addition of UFS to conventional risk scores increased the C-index for PFS and TTP.

Conclusions

UFS can indicate an increased risk for progression into muscle-invasive disease in patients with NMIUC and improves prognostic accuracy of the current clinical risk assessment systems.
High and dry: Trade-off in arboreal calling in a treefrog mediated by local environment
Authors: Cicchino Amanda S , Cairns Nicholas A , Bulté Grégory , Lougheed Stephen C
Published: September 2019

Trade-offs shaping behavioral variation are often influenced by the environment. We investigated the role that the environment plays in mediating trade-offs using a widespread frog with a conspicuous mating display, Pseudacris crucifer. We first demonstrated, using playback and desiccation experiments, that calling site selection involves a trade-off between sound transmission and desiccation. We then determined the influence of local environmental conditions on the intensity of the trade-off by examining range-wide behavioral and environmental data. We showed that the benefit of improved call transmission is positively influenced by vegetation density and ground cover. Behavioral data are consistent with this relationship: sites with a greater transmission benefit have increased prevalence of arboreally calling males. We also found that the prevalence of arboreal calling behavior increases with relative humidity and air temperature, suggesting an influence of these environmental variables on the desiccation cost of arboreal calling. This study provides a clear example of the role of the environment in mediating trade-off intensities and shaping critical behavioral traits.

Local environment mediates the intensity of a trade-off associated with arboreal calling behavior in a treefrog. Combining observational and experimental approaches, we show that arboreal calling behavior increases the transmission of a mating call while potentially subjecting individuals to a rate of desiccation six times greater than terrestrial calling. Local environmental conditions influence both the benefit and the cost of this trade-off, subjecting different populations to varying trade-off intensities and shaping arboreal calling behavior.
Current RNA-seq methodology reporting limits reproducibility
Authors: Simoneau Joël , Dumontier Simon , Gosselin Ryan , Scott Michelle S
Published: September 2019

Ribonucleic acid sequencing (RNA-seq) identifies and quantifies RNA molecules from a biological sample. Transformation from raw sequencing data to meaningful gene or isoform counts requires an in silico bioinformatics pipeline. Such pipelines are modular in nature, built using selected software and biological references. Software is usually chosen and parameterized according to the sequencing protocol and biological question. However, while biological and technical noise is alleviated through replicates, biases due to the pipeline and choice of biological references are often overlooked. Here, we show that the current standard practice prevents reproducibility in RNA-seq studies by failing to specify required methodological information. Peer-reviewed articles are intended to apply currently accepted scientific and methodological standards. Inasmuch as the bias-less and optimal RNA-seq pipeline is not perfectly defined, methodological information holds a meaningful role in defining the results. This work illustrates the need for a standardized and explicit display of methodological information in RNA-seq experiments.
YTH domain family 2 promotes lung cancer cell growth by facilitating 6-phosphogluconate dehydrogenase mRNA translation
Authors: Sheng Hao , Li Zhen , Su Shixin , Sun Wenjing , Zhang Xiaoya , Li Leilei , Li Jing , Liu Shuangping , Lu Bin , Zhang Shuai , Shan Changliang
Published: September 2019

N6-methyladenosine (m6A) is one of widespread post-transcriptional mRNA modifications in eukaryotes and the m6A modification plays critical roles in various human cancers. However, the role of m6A-binding proteins in cancer metabolism remains elusive. Here, we report that YTH domain family 2 (YTHDF2) is upregulated in lung cancer tissues, promotes lung cancer cell growth and enhances the pentose phosphate pathway (PPP) flux, which is crucial for tumor growth. Mechanistically, YTHDF2 directly binds to the m6A modification site of 6-phosphogluconate dehydrogenase (6PGD) three prime untranslated region (3′-UTR) to promote 6PGD mRNA translation in lung cancer cells. Collectively, our data indicate that YTHDF2 acts as a tumor promoter to enhance tumor growth via facilitating 6PGD mRNA translation.
Sputum Gram Stain for Bacterial Pathogen Diagnosis in Community-acquired Pneumonia: A Systematic Review and Bayesian Meta-analysis of Diagnostic Accuracy and Yield
Authors: Ogawa Hiroaki , Kitsios Georgios D , Iwata Mitsunaga , Terasawa Teruhiko
Published: September 2019

Background

The clinical role of sputum Gram stain (SGS) in community-acquired pneumonia (CAP) diagnosis remains controversial. A 1996 meta-analysis of the diagnostic accuracy of SGS reported heterogeneous results. To update the available evidence, we performed a systematic review and a Bayesian standard and latent-class model meta-analysis.

Methods

We searched Medline, Embase, and Cochrane Central by 23 August 2018 to identify studies reporting on the diagnostic accuracy, yield (percentage of patients with any pathogen[s] correctly identified by SGS), and clinical outcomes of SGS in adult patients with CAP. Two reviewers extracted the data. We quantitatively synthesized the diagnostic accuracy and yield, and descriptively analyzed other outcomes.

Results

Twenty-four studies with 4533 patients were included. The methodological and reporting quality of the included studies was limited. When good-quality sputum specimens were selected, SGS had a summary sensitivity of 0.69 (95% credible interval [CrI], .56–.80) and specificity of 0.91 (CrI, .83–.96) for detecting Streptococcus pneumoniae, and a sensitivity of 0.76 (CrI, .60–.87) and specificity of 0.97 (CrI, .91–.99) for Haemophilus influenzae. Adjusted analyses accounting for imperfect reference standards provided higher-specificity estimates than the unadjusted analyses. Bacterial pathogens were identified in 73% (CrI, 26%–96%) of good-quality specimens, and 36% (CrI, 22%–53%) of all specimens regardless of quality. Evidence on other bacteria was sparse.

Conclusions

SGS was highly specific to diagnose S. pneumoniae and H. influenzae infections in patients with CAP. With good-quality specimens, SGS can provide clinically actionable information for pathogen-directed antibiotic therapies.
Adaptive Neuro-Fuzzy Inference System-based Nonlinear Equalizer for CO-OFDM Systems
Authors: Raj Ajay Amrit ,   Dejey
Published: September 2019

The principle of orthogonal frequency-division multiplexing (OFDM) is to transmit the data through a large number of multiple orthogonal subcarriers. The coherent optical OFDM (CO-OFDM) is OFDM data that are being modulated to light frequency and being detected in coherent manner. CO-OFDM brings to optical communications the combination of two powerful techniques, coherent optical detection and OFDM. One of the primary challenges in the CO-OFDM system is to remove optical fiber nonlinear effects. This makes nonlinearity compensation a critical task of the CO-OFDM system. So a nonlinear equalizer (NLE) based on adaptive neuro-fuzzy inference system (ANFIS) is presented for CO-OFDM systems to mitigate nonlinearities on long-haul optical communications with high bit rate and bit error rate (BER)of the system. Various performance metrics were analyzed for the proposed ANFIS–NLE, and it is compared with existing techniques such as support vector machine and artificial neural network. From the experimental results, our proposed approach gives better performance in terms of BER and Q-factor on comparing with existing methods.
CalBehav: A Machine Learning-Based Personalized Calendar Behavioral Model Using Time-Series Smartphone Data
Authors: Sarker Iqbal H , Colman Alan , Han Jun , Kayes A S M , Watters Paul
Published: September 2019

The electronic calendar is a valuable resource nowadays for managing our daily life appointments or schedules, also known as events, ranging from professional to highly personal. Researchers have studied various types of calendar events to predict smartphone user behavior for incoming mobile communications. However, these studies typically do not take into account behavioral variations between individuals. In the real world, smartphone users can differ widely from each other in how they respond to incoming communications during their scheduled events. Moreover, an individual user may respond the incoming communications differently in different contexts subject to what type of event is scheduled in her personal calendar. Thus, a static calendar-based behavioral model for individual smartphone users does not necessarily reflect their behavior to the incoming communications. In this paper, we present a machine learning based context-aware model that is personalized and dynamically identifies individual’s dominant behavior for their scheduled events using logged time-series smartphone data, and shortly name as ‘CalBehav’. The experimental results based on real datasets from calendar and phone logs, show that this data-driven personalized model is more effective for intelligently managing the incoming mobile communications compared to existing calendar-based approaches.
Jordan centre in random trees: persistence and distance to root
Authors: Pattathil Sarath , Karamchandani Nikhil , Shah Dhruti
Published: September 2019

The Jordan centre of a graph is defined as a vertex whose maximum distance to other nodes in the graph is minimal, and it finds applications in facility location and source detection problems. We study properties of the Jordan centre in the case of random growing trees. In particular, we consider a regular tree graph on which an infection starts from a root node and then spreads along the edges of the graph according to various random spread models. For the Independent Cascade (IC) model and the discrete Susceptible Infected (SI) model, both of which are discrete-time models, we show that as the infected subgraph grows with time, the Jordan centre persists on a single vertex after a finite number of timesteps. As a corollary of our results, we also establish that the distance between the Jordan centre and the infection source (root node) is finite. Finally, we also study the continuous-time version of the SI model and bound the maximum distance between the Jordan centre and the root node at any time.
Stress-induced remodelling of the mitral valve: a model for leaflet thickening and superimposed tissue formation in mitral valve disease
Authors: Kruithof Boudewijn P T , Paardekooper Laura , Hiemstra Yasmine L , Goumans Marie-José , Palmen Meindert , Delgado Victoria , Klautz Robert J M , Ajmone Marsan Nina
Published: September 2019

Aims

In mitral valve prolapse (MVP), leaflet thickening has recently been suggested to be due, in addition to a myxomatous degeneration, to the presence of a superimposed tissue (SIT), defined as an additional fibrous layer on top of the original leaflet. The mechanisms of SIT formation are currently unknown. We hypothesized that SIT formation would result from excessive leaflet stress and we used a unique ex vivo model to assess the correlation between leaflet remodelling and the type and location of mechanical stress and to elucidate the mechanisms underlying SIT formation.

Methods and results

Human diseased mitral valves (MVs; n = 21) were histologically analysed for SIT formation and original leaflet thickening. The SIT comprised of various compositions of extracellular matrix and could reach more than 50% of total leaflet thickness. Original leaflet and SIT thickness did not show significant correlation (r = −0.27, P = 0.23), suggesting different regulatory mechanisms. To study the role of the mechanical environment on MV remodelling, mouse MV were cultured in their natural position in the heart and subjected to various haemodynamic conditions representing specific phases of the cardiac cycle and the MVP configuration. SIT formation was induced in the ex vivo model, mostly present on the atrial side, and clearly dependent on the duration, type, and extent of mechanical stress. Specific stainings and lineage tracing experiments showed that SIT comprises of macrophages and myofibroblasts and is associated with the activation of the transforming growth factor-beta and bone morphogenetic protein signalling pathways. Migration of valvular interstitial cells and macrophages through breakages of the endothelial cell lining contributed to SIT formation.

Conclusions

Mechanical stresses induce specific cellular and molecular changes in the MV that result in SIT formation. These observations provide the first insights in the mechanism of SIT formation and represent an initial step to identify potential novel and early treatment for MVP.
Perception of the Müller–Lyer illusion in guppies
Authors: Santacà Maria , Agrillo Christian
Published: September 2019

The Müller–Lyer illusion is a well-known distortion illusion that occurs when the spatial arrangement of inducers (i.e., inwards- or outwards-pointing arrowheads) influences a line’s perceived relative length. To date, this illusion has been reported in several animal species but only in 1 teleost fish (i.e., redtail splitfins Xenotoca eiseni), although teleost fish represent approximately 50% of vertebrate diversity. We investigated the perception of this illusion in another teleost fish: guppies Poecilia reticulata, a species that diverged from the redtail splitfin 65 million years ago. The guppies were trained to select the longer between 2 lines; after meeting the learning criterion, illusory trials were presented. Control trials were also arranged to exclude the possibility that their choices were based on potential spatial biases that relate to the illusory pattern. The guppies’ overall performance indicated that they were susceptible to the Müller–Lyer illusion, perceiving the line with the inwards-pointing arrowheads as longer. The performance in the control trials excluded the possibility that the subjects used the physical differences between the 2 figures as the discriminative cue in the illusory trials. Our study suggests that sensibility to the Müller–Lyer illusion could be widespread across teleost fish and reinforces the idea that the perceptual mechanisms underlying size estimation might be similar across vertebrates.
Reproductive biology of the greater bandicoot rat Bandicota indica (Rodentia: Muridae) in the rice fields of southern Thailand
Authors: Thitipramote N. , Suwanjarat J. , Breed W. G.
Published: September 2019

This study investigated some aspects of the reproductive biology of male and female greater bandicoot rats, Bandicota indica, in southern Thailand from September 2004 to September 2006. In females, body, uterine and preputial gland weights, occurrences of pregnancies and placental scars, and in males, testicular weights and histology, and sizes of accessory sex glands, were recorded. Pregnancies occurred predominantly, but not exclusively, in the wet season, with a higher incidence pregnancies in the second, than in the first, dry season. Uterine and preputial gland weights tended to be lower in the first, but not the second dry season, with placental scars occurring at all times of year. Males tended to have heavier testes in the wet season but some seminiferous tubules contained sperm even in the dry season. Seminal vesicles, but not prostates and preputial glands, tended to be heavier in animals in the wet season. We conclude that the greater bandicoot rat in southern Thailand shows maximal reproductive activity in the wet season with some reproductive activity, albeit variable from year to year, occurring in the dry season depending upon environmental conditions. This study has also shown that females, as well as males, have large preputial glands, and that males invariably have small testes regardless of the time of year. These observations suggest a similar timing of reproduction, but a different breeding biology and perhaps social organisation, from that of the sympatric ricefield rat, Rattus argentiventer
Variations in reproductive strategies between one invasive population and two native populations of Pseudorasbora parva
Authors: Yan Yunzhi , Chen Yifeng
Published: September 2019

Reproductive traits of one invasive population in Lake Fuxian and two native populations in Lakes Chao and Dongting for Pseudorasbora parva were investigated to determine the variations in their reproductive strategies associated with the change of environmental conditions. Compared with the two native populations, P. parva markedly experienced the protraction in their spawning time and the decrease in mortality for adult individuals in Lake Fuxian. The three populations all got their first sexual maturity at the same age, but their total lengths at maturity were quite different for those in Lake Chao were significantly lower than in Lakes Fuxian and Dongting. Additionally, in spite that no significant difference occurred in their relative fecundities for P. parva in Lakes Fuxian and Dongting, the population in Lake Chao showed the markedly higher relative fecundity than the other two populations. These results were analyzed with the variations in water temperature, nutrient status, fishing stress among the three lakes. The relative decline in fecundity for the invasive population, which conflicted with the enemy release hypothesis, was disscussed with the context of the preponderance of another invasive fish, Neosalanx taihuensis, in Lake Fuxian.
Comparison of locomotor behaviour between white-headed langurs Trachypithecus leucocephalus and François’ langurs T .françoisi in Fusui, China
Authors: Xiong Jinrong , Gong Shihua , Qiu Chenggang , Li Zhaoyuan
Published: September 2019

We studied the locomotor behaviour of white-headed langurs Trachypithecus leucocephalus and François’ langurs T .françoisi to test two hypotheses: (1) these monkeys have evolved locomotor ability to support their activities on limestone hills, and (2) François’ langurs have evolved more diverse locomotor skills than white-headed langurs. Data were collected from 1996 - 1998 and in 2005 in Fusui Nature Reserve, Guangxi, and showed that the two species had similar locomotor types, but François’ langurs had more locomotor modes (26) than white-headed langurs (12). Quadrupedal walking and leaping were two major types, and white-headed langurs were more arboreal than François’ langurs. We suggest that, while keeping their ancestral locomotor types, the two species have evolved new types allowing them to live on limestone cliffs. Compared to white-headed langurs, François’ langurs have more diverse locomotor modes that probably have allowed them to live in more habitat types. As an evolutionary outcome’ François’ langurs have a larger distribution range.
The bottlenose dolphin Tursiops truncatus foraging around a fish farm: Effects of prey abundance on dolphins’ behavior
Authors: Díaz López Bruno
Published: September 2019

The extent to which prey abundance influences both bottlenose dolphin foraging behavior and group size in the presence of human activities has not previously been studied. The primary aim of this study was to identify and quantify how wild bottlenose dolphins respond, individually and as groups, to the relative abundance of prey around a fish farm. Detailed views of dolphins’ behavior were obtained by focal following individual animals whilst simultaneously collecting surface and underwater behavioral data. A total of 2150 dive intervals were analyzed, corresponding to 342 focal samples, lasting over 34 hours. Bottlenose dolphins remained submerged for a mean duration of 46.4 seconds and a maximum of 249 seconds. This study provides the first quantified data on bottlenose dolphin diving behavior in a marine fin-fish farm area. This study’s results indicate that within a fish farm area used intensively by bottlenose dolphins for feeding, dolphins did not modify dive duration. Additionally, underwater observations confirmed that dolphins find it easier to exploit a concentrated food source and it appears that hunting tactic and not group size plays an important role during feeding activities. Thus, bottlenose dolphins appear capable of modifying their hunting tactics according to the abundance of prey. When top predators display behavioral responses to activities not directed at them, the task of studying all possible effects of human activities can become even more challenging.
Heat, sight and scent: multiple cues influence foraging site selection by an ambush-foraging snake Hoplocephalus bungaroides (Elapidae)
Authors: Du Weiguo , K. Webb Jonathan , Shine Richard
Published: September 2019

Most mobile organisms respond to multiple cues when selecting habitat types, and laboratory experiments that manipulate only single cues may fail to reveal the true complexity of habitat-selection behaviour. In south- eastern Australia, broad headed snakes Hoplocephalus bungaroides (Elapidae) lie in wait under sun-warmed rocks to ambush velvet geckos Oedura leseuerii (Gekkonidae). Previous laboratory work has shown that both the geckos and the snakes actively select hotter rather than colder rocks, and that the snakes actively select rocks scented by geckos. We manipulated rock temperature and the presence of two types of cues from geckos (chemical and visual information) to clarify the causal basis for foraging site selection by the juveniles of this snake. When given a choice between cold lizard-scented rocks and hot unscented rocks, our captive snakes gave a higher priority to lizard scent than to temperature. The snakes also selected shelter-sites that provided visual as well as scent cues from lizards, rather than shelter-sites with scent cues alone. Thus, although broad-headed snakes show a direct preference for hotter rather than colder rocks in the laboratory, their choice of foraging site in the field may also be influenced by the presence of scent cues from prey. Our laboratory results suggest that habitat selection by broad-headed snakes may be more complex than has been suggested by previous single-factor laboratory trials.
Comparison of social interaction and neural activation in the main olfactory bulb and the accessory olfactory bulb between Microtus mandarinus and Microtus fortis
Authors: Tai Fadao , Wang Wanying , Broders Hugh , Sun Ruyong , Liu Limin , Wang Hongyuan
Published: September 2019

To gain insight into the function of AOB and MOB during different social interaction and in different vole species, the behaviors and neural activation of the olfactory bulbs in social interactions of mandarin voles Microtus mandarinus and reed voles Microtus fortis were compared in the present research. Mandarin voles spent significantly more time attacking and sniffing their opponents and sniffing sawdust than reed voles. During same sex encounters, mandarin voles attacked their opponents for a significantly longer time and sniffed its opponent for shorter time compared with male-female interactions. However, no significant behavioral differences were found during encounters of two individual reed voles, regardless of gender composition of the pair. Using c-Fos as an indicator of neural activation, we observed that neural activation was significantly higher in almost all sub-regions of the main olfactory bulb (MOB) and the accessory olfactory bulb (AOB) of mandarin voles compared with reed voles. Numbers of c-Fos-ir neurons in almost all sub-regions of the AOB and the MOB during male-female interactions were also higher than those in interactions of the same sex. Anterior-posterior ratios of Fos-ir neurons in the AOBM (AOBMR) and the AOBG (AOBGR) in male-female interaction were significantly higher than those in interaction of the same sex. The AOBMR of male mandarin voles and reed voles were larger than those of females in male-female interactions. Behavioral patterns are consistent with cellular activity patterns. Consistent level of neural activation in MOB and AOB suggests important roles of both the main olfactory bulb and the accessory olfactory bulb in social interaction in two species.
The function of animal ‘eyespots’: Conspicuousness but not eye mimicry is key
Authors: Stevens Martin , Cantor Abi , Graham Julia , Winney Isabel S.
Published: September 2019

Many animals are marked with conspicuous circular features often called ‘eyespots’, which intimidate predators, preventing or halting an attack. It has long been assumed that eyespots work by mimicking the eyes of larger animals, but recent experiments have indicated that conspicuousness and contrast is important in eyespot function, and not eye mimicry. We undertake two further experiments to distinguish between the conspicuousness and mimicry hypotheses, by using artificial prey presented to wild avian predators in the field. In experiment 1, we test if eyespot effectiveness depends on the marking shape (bar or circle) and arrangement (eye-like and non-eye-like positions). We find no difference between shapes or arrangement; all spots were equally effective in scaring birds. In experiment 2, we test if the often yellow and black colors of eyespots mimic the eyes of birds of prey. We find no effect of shape, and no advantage to yellow and black spots over non-eye-like but equally conspicuous colors. The consistent finding is that eyespot function lies in being a conspicuous signal to predators, and not necessarily due to eye mimicry.
The role of ultrasonic bat detectors in improving inventory and monitoring surveys in Vietnamese karst bat assemblages
Authors: Furey Neil M. , Mackie Iain J. , Racey Paul A.
Published: September 2019

Bats account for 30% of mammal diversity in SE Asia and are potential bioindicators of wider biodiversity impacts resulting from habitat loss and climate change. As existing sampling techniques in the region typically fail to record bats that habitually fly in open areas and at higher altitudes, current inventory efforts are less than comprehensive. Acoustic sampling with bat detectors may help to overcome these limitations for insectivorous bats, but has yet to be tested in mainland SE Asia. To do so, we sampled bats while simultaneously recording the echolocation calls of insectivorous species commuting and foraging in a variety of karst habitats in north Vietnam. Monitoring of cave-dwelling bats was also undertaken. Discriminant function analysis of 367 echolocation calls produced by 30 insectivorous species showed that acoustic identification was feasible by correctly classifying 89. l % of calls. In all habitats, acoustic sampling and capture methods recorded significantly more species each night than capture methods alone. Capture methods consequently failed to record 29 % (ten spp. of aerial insectivores) of the bat fauna in commuting and foraging habitats and 11% (two spp.) of that in our cave sample. Only four of these species were subsequently captured following significantly greater sampling effort. This strongly suggests that acoustic methods are indispensable for maximizing bat inventory completeness in SE Asia. As accurate inventories and monitoring are essential for effective species conservation, we recommend the inclusion of acoustic sampling in future studies of bat assemblages across the region.
The reproductive biology of a Central American cichlid Neetroplus nematopus in Lake Xiloá, Nicaragua
Authors: McKaye Kenneth R. , Hale Jeremy , van den Berghe Eric P.
Published: September 2019

This study was conducted to provide a five-year database on the breeding seasonality and breeding biology of a Central American cichlid fish Neetroplus nematopus, a biparental substratum-spawning cichlid that cares for its eggs, wrigglers, and fry for up to six weeks. A total of 503 breeding pairs were monitored for breeding success. Breeding pairs of N. nematopus are sexually dimorphic in size, with females averaging 39% of male body mass. Fry emerged from 85% of nesting cavities. After three weeks, only 30% of the broods were present in the nesting cavity; these broods had a 30% survival rate, giving a 9% overall survival rate. Nineteen percent of the successful parents with three-week-old broods adopted foreign fry. A consistent unimodal breeding peak in December was observed for five years. This breeding peak differed dramatically from the bimodal breeding season 20 years found in the 1970s. The effects of extensive grenade fishing practices during the 1980s might have played a substantial role in the observed change. Grenade fishing stopped in 1991, and the number of N. nematopus pairs increased by 136% from 1990 to 1995. With increased density of breeding fish, the breeding season for this species also expanded. The balance between divergent selection due to competition for breeding sites and stabilizing selection due to predation pressure on offspring is likely to mold the breeding season for N. nematopus and other cichlids of Lake Xiloá. We suggest that brood adoption and synchrony of breeding is a strategy to reduce predation on the parent's own young.