bluuebunny/crossref_metadata_2025 huggingface dataset:
A particle swarm optimization method for interpreting self-potential anomalies
Authors: Essa Khalid S
Published: May 2019

This paper describes the use of the particle swarm optimization (PSO) method for interpreting observed self-potential anomalies measured along a profile. First, the technique applies the second moving average to the observed self-potential data in order to eradicate the possible influence of the regional anomaly (up to the third-order polynomial effect) via the filter of consecutive window lengths (s-values) and to calculate the residual anomaly. Following that, the PSO method is applied to the residual response to infer the source parameters: amplitude coefficient (K), depth (z), polarization angle (θ) and the shape factor (q) of the underlying buried target. The technique has been applied to three different theoretical and two field examples from the USA and Turkey. Comparisons have shown that the source parameters retrieved from the technique described here are in good agreement with the available geologic and geophysical information.
State Variation in Early-Onset Colorectal Cancer in the United States, 1995–2015
Authors: Siegel Rebecca L , Medhanie Genet A , Fedewa Stacey A , Jemal Ahmedin
Published: May 2019

The extent to which the increase in early-onset colorectal cancer (CRC) in the United States varies geographically is unknown. We analyzed changes in CRC incidence and risk factors among people aged 20–49 years by state using high-quality population-based cancer registry data provided by the North American Association of Central Cancer Registries and national survey data, respectively. Early-onset CRC incidence was mostly stable among blacks and Hispanics but increased in 40 of 47 states among non-Hispanic whites, most prominently in western states. For example, rates increased in Washington from 6.7 (per 100 000) during 1995–1996 to 11.5 during 2014–2015 (rate ratio = 1.73, 95% confidence interval = 1.48 to 2.01) and in Colorado from 6.0 to 9.5 (rate ratio = 1.57, 95% confidence interval = 1.30 to 1.91). Nevertheless, current CRC incidence was highest in southern states. From 1995 to 2005, increases occurred in obesity prevalence in all states and heavy alcohol consumption in one-third of states, but neither were correlated with CRC incidence trends. Early-onset CRC is increasing most rapidly among whites in western states. Etiologic studies are needed to explore early life colorectal carcinogenesis.
Interventions On-Call: Dynamic Adaptive Design in the 2015 National Survey of College Graduates
Authors: Coffey Stephanie , Reist Benjamin , Miller Peter V
Published: May 2019

This article illustrates some effects of dynamic adaptive design in a large government survey. We present findings from the 2015 National Survey of College Graduates Adaptive Design Experiment, including results and discussion of sample representativeness, response rates, and cost. We also consider the effect of truncating data collection (examining alternative stopping rules) on these metrics. In this experiment, we monitored sample representativeness continuously and altered data collection procedures—increasing or decreasing contact effort—to improve it. Cases that were overrepresented in the achieved sample were assigned to more passive modes of data collection (web or paper) or withheld from the group of cases that received survey reminders, whereas underrepresented cases were assigned to telephone follow-ups. The findings suggest that a dynamic adaptive survey design can improve a data quality indicator (R-indicators) without increasing cost or reducing response rate. We also find that a dynamic adaptive survey design has the potential to reduce the length of the data collection period, control cost, and increase timeliness of data delivery, if sample representativeness is prioritized over increasing the survey response rate.
Fickian and non-Fickian diffusion of cosmic rays
Authors: Rodrigues Luiz F S , Snodin Andrew P , Sarson Graeme R , Shukurov Anvar
Published: May 2019

Fluid approximations to cosmic ray (CR) transport are often preferred to kinetic descriptions in studies of the dynamics of the interstellar medium (ISM) of galaxies, because they allow simpler analytical and numerical treatments. Magnetohydrodynamic simulations of the ISM usually incorporate CR dynamics as an advection–diffusion equation for CR energy density, with anisotropic, magnetic-field-aligned diffusion with the diffusive flux assumed to obey Fick’s law. We compare test particle and fluid simulations of CRs in a random magnetic field. We demonstrate that a non-Fickian prescription of CR diffusion, which corresponds to the telegraph equation for the CR energy density, can be easily calibrated to match the test particle simulations with great accuracy. In particular, we consider a random magnetic field in the fluid simulation that has a lower spatial resolution than that used in the particle simulation to demonstrate that an appropriate choice of the diffusion tensor can account effectively for the unresolved (subgrid) scales of the magnetic field. We show that the characteristic time that appears in the telegraph equation can be physically interpreted as the time required for the particles to reach a diffusive regime and we stress that the Fickian description of the CR fluid is unable to describe complex boundary or initial conditions for the CR energy flux.
DNA specificities modulate the binding of human transcription factor A to mitochondrial DNA control region
Authors: Cuppari Anna , Fernández-Millán Pablo , Battistini Federica , Tarrés-Solé Aleix , Lyonnais Sébastien , Iruela Guillermo , Ruiz-López Elena , Enciso Yuliana , Rubio-Cosials Anna , Prohens Rafel , Pons Miquel , Alfonso Carlos , Tóth Katalin , Rivas Germán , Orozco Modesto , Solà Maria
Published: May 2019

Human mitochondrial DNA (h-mtDNA) codes for 13 subunits of the oxidative phosphorylation pathway, the essential route that produces ATP. H-mtDNA transcription and replication depends on the transcription factor TFAM, which also maintains and compacts this genome. It is well-established that TFAM activates the mtDNA promoters LSP and HSP1 at the mtDNA control region where DNA regulatory elements cluster. Previous studies identified still uncharacterized, additional binding sites at the control region downstream from and slightly similar to LSP, namely sequences X and Y (Site-X and Site-Y) (Fisher et al., Cell 50, pp 247–258, 1987). Here, we explore TFAM binding at these two sites and compare them to LSP by multiple experimental and in silico methods. Our results show that TFAM binding is strongly modulated by the sequence-dependent properties of Site-X, Site-Y and LSP. The high binding versatility of Site-Y or the considerable stiffness of Site-X tune TFAM interactions. In addition, we show that increase in TFAM/DNA complex concentration induces multimerization, which at a very high concentration triggers disruption of preformed complexes. Therefore, our results suggest that mtDNA sequences induce non-uniform TFAM binding and, consequently, direct an uneven distribution of TFAM aggregation sites during the essential process of mtDNA compaction.
MEXPRESS update 2019
Authors: Koch Alexander , Jeschke Jana , Van Criekinge Wim , van Engeland Manon , De Meyer Tim
Published: May 2019

The recent growth in the number of publicly available cancer omics databases has been accompanied by the development of various tools that allow researchers to visually explore these data. In 2015, we built MEXPRESS, an online tool for the integration and visualization of gene expression, DNA methylation and clinical data from The Cancer Genome Atlas (TCGA), a large collection of publicly available multi-omics cancer data. MEXPRESS addresses the need for an easy-to-use, interactive application that allows researchers to identify dysregulated genes and their clinical relevance in cancer. Furthermore, while other tools typically do not support integrated visualization of expression and DNA methylation data in combination with the precise genomic location of the methylation, MEXPRESS is unique in how it depicts these diverse data types together. Motivated by the large number of users MEXPRESS has managed to attract over the past 3 years and the recent migration of all TCGA data to a new data portal, we developed a new version of MEXPRESS (https://mexpress.be). It contains the latest TCGA data, additional types of omics and clinical data and extra functionality, allowing users to explore mechanisms of gene dysregulation beyond expression and DNA methylation.
Trends in and Correlates of Use of Roll-Your-Own Cigarettes: A Population Study in England 2008–2017
Authors: Jackson Sarah E , Shahab Lion , Garnett Claire , Brown Jamie
Published: May 2019

Introduction

Understanding the use of cheaper roll-your-own (RYO) cigarettes may have implications for tobacco tax policy. We examined trends in RYO cigarette use in England between 2008 and 2017, and characterized users’ sociodemographic and smoking profiles.

Methods

We used data from 211 469 respondents to a survey representative of the adult (≥16 years) population. In current smokers across the entire study period (n = 43 389), we assessed multivariable associations between cigarette type (RYO or factory-made [FM]) and sociodemographic and smoking characteristics. Among current smokers in 2008 and 2017 (n = 7685), we tested interactions between year and cigarette type to assess the stability of each characteristic.

Results

Between 2008 and 2017, FM cigarette use declined from 15.3% to 9.2% whereas RYO use increased from 6.7% to 8.1%. Greater odds of RYO use were observed among younger, male smokers from lower social grades, who were more addicted and used electronic cigarettes (ORrange = 1.28–1.86, p < .001). Lower odds of RYO use were observed among nondaily smokers, those with high motivation to stop, and higher spending on smoking (ORrange = 0.46–0.89, p ≤ .001). The RYO smoker profile was relatively stable between 2008 and 2017. However, compared with FM use, RYO use increased in younger (p < .001) and female (p = .019) smokers, and there was a relatively smaller decline in the proportion cutting down or trying to quit (p = .004).

Conclusion

In England, RYO use increased when overall smoking prevalence and FM use decreased. The profile of RYO smokers remained relatively stable, with users typically younger, male, more addicted, deprived, spending less on smoking, and less inclined to quit than FM smokers.

Implications

This population-based study provides novel insight into recent trends in RYO use in England, providing an up-to-date understanding of the profile of RYO smokers. Without the consistent application of tax across the range of combustible products, smokers who are more dependent are able to capitalize on the lower cost of RYO in order to continue smoking, undermining the potential benefit of taxation on cessation.
The conundrum of dietary antioxidants in cancer chemotherapy
Authors: Ilghami Roghayeh , Barzegari Abolfazl , Mashayekhi Mohammad Reza , Letourneur Didier , Crepin Michel , Pavon-Djavid Graciela
Published: May 2019

Although chemotherapy succeeds in reducing tumor burden, the efficacy is limited due to acquired drug resistance and often irreparable side effects. Studies show that antioxidants may influence the response to chemotherapy and its side effects, although their use remains controversial. The evidence shows that some chemo-drugs induce oxidative stress and lead to normal tissue apoptosis and the entry of cancer cells to a dormant G0 state. Through the suppression of oxidative stress, antioxidants could protect normal cells and bring the tumor out of dormancy so as to expose it to chemotherapies. This review is focused on the redox biology of cancer/normal cells and association of reactive oxygen species with drug resistance, cancer dormancy, and side effects. To this end, evidence from cellular, animal, and clinical studies is provided to better understand the conundrum of dietary antioxidants in cancer chemotherapy.
Customized “Whole-Cervical-Vertebral-Body” Reconstruction After Modified Subtotal Spondylectomy of C2-C7 Spinal Tumor Via Piezoelectric Surgery
Authors: He Shaohui , Yang Xinghai , Yang Jian , Ye Chen , Liu Weibo , Wei Haifeng , Xiao Jianru
Published: May 2019

BACKGROUND

Radical resection is the first-line option in managing cervical primary chondrosarcoma. Favorable anterior reconstruction is challenging after multilevel total spondylectomy in the cervical spine.

OBJECTIVE

To illustrate the application of piezoelectric surgery and three-dimensional (3D) printing techniques in spine surgery.

METHODS

A 27-yr-old patient was referred to our center with complaints of nocturnal neck pain and right upper extremity weakness. A 2-stage radical tumor resection was conducted using piezoelectric surgery with pathologically tumor-free margins. A 3D-printed titanium microporous prosthesis (3D-PTMP) was designed to reconstruct the anterior column of the cervical spine between C1 and T1 for stability.

RESULTS

The whole intraoperative blood loss was 2300 mL over the 2 procedures. The patient had an uneventful recovery, regaining ambulatory status 3 wk after the 2 operations without ventilator support or other severe complications. By the final 14-mo follow-up, the patient had achieved marked pain relief and favorable neurological improvement; a postoperative computed tomography scan indicated a good position of the 3D-printed construct between the endplates with no sign of tumor recurrence or implant subsidence.

CONCLUSION

The applications of piezosurgery in total spondylectomy and in 3D-PTMP in reconstruction can be a favorable alternative for managing multilevel cervical spinal tumors. Further studies are warranted to validate this surgical strategy.
Slave Hounds and Abolition in the Americas*
Authors: Parry Tyler D , Yingling Charlton W
Published: May 2019

The lash and shackles remain two primary symbols of material degradation fixed in the historical memory of slavery in the Americas. Yet as recounted by states, abolitionists, travellers, and most importantly slaves themselves, perhaps the most terrifying and effective tool for disciplining black bodies and dominating their space was the dog. This article draws upon archival research and the published materials of former slaves, novelists, slave owners, abolitionists, Atlantic travelers, and police reports to link the systems of slave hunting in Cuba, Jamaica, Haiti, and the US South throughout the eighteenth and nineteenth centuries. Slave hounds were skillfully honed biopower predicated upon scenting, hearing, sighting, outrunning, outlasting, signaling, attacking, and sometimes terminating, black runaways. These animals permeated slave societies throughout the Americas and bolstered European ambitions for colonial expansion, indigenous extirpation, economic extraction, and social domination in slave societies. as dogs were bred to track and hunt enslaved runaways, slave communities utilized resources from the natural environment to obfuscate the animal's heightened senses, which produced successful escapes on multiple occasions. This insistence of slaves' humanity, and the intensity of dog attacks against black resistance in the Caribbean and US South, both served as proof of slavery's inhumanity to abolitionists. Examining racialized canine attacks also contextualizes representations of anti-blackness and interspecies ideas of race. An Atlantic network of breeding, training and sales facilitated the use of slave hounds in each major American slave society to subdue human property, actualize legal categories of subjugation, and build efficient economic and state regimes. This integral process is often overlooked in histories of slavery, the African Diaspora, and colonialism. By violently enforcing slavery’s regimes of racism and profit, exposing the humanity of the enslaved and depravity of enslavers, and enraging transnational abolitionists, hounds were central to the rise and fall of slavery in the Americas.
Perineural Platelet-Rich Plasma for Diabetic Neuropathic Pain, Could It Make a Difference?
Authors: Hassanien Manal , Elawamy Abdelraheem , Kamel Emad Zarief , Khalifa Walaa A , Abolfadl Ghada Mohamed , Roushdy Al Shimaa Ismael , El Zohne Randa A , Makarem Yasmine S
Published: May 2019

Objective

To evaluate the clinical effect of perineural platelet-rich plasma (PRP) injection for pain and numbness alleviation in diabetic peripheral neuropathy (DPN).

Study Design

A randomized prospective clinical trial.

Setting

Pain clinic and Rheumatology and Rehabilitation Departments, Assiut University Hospital.

Methods

Sixty adult patients with type II DM accompanied by DPN of at least six months’ duration were assessed by modified Toronto Clinical Neuropathy Score (mTCNS) and randomly allocated into two groups. Group I underwent ultrasound-guided perineural PRP injection and medical treatment, and Group II received medical treatment only. Patients were followed up at months 1, 3, and 6 with regard to pain and numbness visual analog scale (VAS) and mTCNS scores.

Results

Significant improvement was recorded in pain and numbness VAS scale scores in group I vs group II (P ≤ 0.001 during the whole study period for both parameters); at the same time, mTCNS improved in group I in comparison with group II with P = 0.01, 0.001, and <0.001 at months 1, 3, and 6, respectively.

Conclusions

Perineural PRP injection is an effective therapy for alleviation of diabetic neuropathy pain and numbness and enhancement of peripheral nerve function.
Enemy or Ally? Elites, Base Relations, and Partisanship in America
Authors: Kane John V
Published: May 2019

A wealth of research demonstrates that partisans dismiss information that challenges their attitudes toward political elites, especially when citizens are aware of these elites’ party membership. Relatively little is known, however, about the conditions under which partisans will adjust their support for such elites. Drawing upon research on the group-foundations of partisanship, I hypothesize that, issues and policy stances aside, partisans’ support for, and willingness to compromise with, a given elite is contingent upon how well the elite relates to the groups associated with his or her party (i.e., the party’s “base”). In short, partisans should be inclined to exhibit greater political support for, and greater willingness to compromise with, the enemy of their socio-political enemies, but less support for the enemy of their socio-political allies. Findings from survey experiments and observational analyses involving real-world executives offer strong empirical support for these contentions. Thus, while acknowledging the powerful effects of cues involving elites’ party labels, this study reveals that “base relations” cues can potentially counteract the motivated reasoning processes that arise from partisans’ attentiveness to party cues alone. Such effects should be observed, I argue, precisely because base relations cue an elite’s fidelity to the very groups that endow the party label with its symbolic meaning. Therefore, more broadly, this study advances our understanding of polarization by demonstrating an important way in which politically aligned social groups underpin American partisanship and public opinion.
Cutaneous leishmaniasis in north Lebanon: re-emergence of an important neglected tropical disease
Authors: El Safadi Dima , Merhabi Sabah , Rafei Rayane , Mallat Hassan , Hamze Monzer , Acosta-Serrano Alvaro
Published: May 2019

Background

Cutaneous leishmaniasis (CL) is the most prevalent neglected tropical disease among externally displaced people in the Middle East. In recent years, the Lebanese population has increased >30%, mainly due to a mass influx of Syrian migrants, thousands of them carrying CL, among other infectious diseases. Here we revisit the current CL prevalence among refugees in northern Lebanon.

Methods

This cohort study was conducted at the Al Bashaer Medical Center in north Lebanon between January and June 2017. A total of 48 randomly selected suspected CL patients were clinically diagnosed by dermatologists and samples were obtained for microscopic examination and molecular identification by polymerase chain reaction restriction fragment length polymorphism. The treatment response to antimonials was assessed each week and was followed for up 6 months.

Results

Leishmania tropica was the predominant species (91.7%) followed by Leishmania major (8.3%). Confirmed cases were treated with one to two courses of antimonials and healing was usually achieved after receiving a second course of treatment. Importantly, we show evidence of possible local CL transmission by indigenous sandflies in three separate patients who had no history of recent travel to Syria.

Conclusions

This highlights the urgent necessity to implement preventive disease strategies to avoid further dispersion of L. tropica CL in north Lebanon.
Insulin-insensitivity of male genitalia maintains reproductive success inDrosophila
Authors: Dreyer Austin P. , Shingleton Alexander W.
Published: May 2019

For most arthropod species, male genital size is relatively implastic in response to variation in developmental nutrition, such that the genitals in large well-fed males are similar in size to those in small poorly-fed males. InDrosophila melanogaster,reduced nutritional plasticity of the male genitalia is a consequence of low insulin sensitivity through a tissue-specific reduction in the expression ofFOXO, a negative growth regulator.Despite an understanding of the proximate developmental mechanisms regulating organ size, the ultimate evolutionary mechanisms that may have led to reducedFOXOexpression in the genitalia have not been fully elucidated. Here we show that restoring FOXO activity in the developing genitalia reduces the male genital size and decreases various aspects of male reproductive success. These data support the hypothesis that sexual selection has acted on the male genitalia to limit their nutritional plasticity through a reduction inFOXOexpression, linking proximate with ultimate mechanisms of genital evolution.
Large brains, short life: selection on brain size impacts intrinsic lifespan
Authors: Kotrschal Alexander , Corral-Lopez Alberto , Kolm Niclas
Published: May 2019

The relationship between brain size and ageing is a paradox. The cognitive benefits of large brains should protect from extrinsic mortality and thus indirectly select for slower ageing. However, the substantial energetic cost of neural tissue may also impact the energetic budget of large-brained organisms, causing less investment in somatic maintenance and thereby faster ageing. While the positive association between brain size and survival in the wild is well established, no studies exist on the direct effects of brain size on ageing. Here we test how brain size influences intrinsic ageing in guppy (
Poecilia reticulata
) brain size selection lines with 12% difference in relative brain size. Measuring survival under benign conditions, we find that large-brained animals live 22% shorter than small-brained animals and the effect is similar in both males and females. Our results suggest a trade-off between investment into brain size and somatic maintenance. This implies that the link between brain size and ageing is contingent on the mechanism of mortality, and selection for positive correlations between brain size and ageing should occur mainly under cognition-driven survival benefits from increased brain size. We show that accelerated ageing can be a cost of evolving a larger brain.
Spatio-temporal integration in plant tropisms
Authors: Meroz Yasmine , Bastien Renaud , Mahadevan L.
Published: May 2019

Tropisms, growth-driven responses to environmental stimuli, cause plant organs to respond in space and time and reorient themselves. Classical experiments from nearly a century ago reveal that plant shoots respond to the integrated history of light and gravity stimuli rather than just responding instantaneously. We introduce a temporally non-local response function for the dynamics of shoot growth formulated as an integro-differential equation whose solution allows us to qualitatively reproduce experimental observations associated with intermittent and unsteady stimuli. Furthermore, an analytic solution for the case of a pulse stimulus expresses the response function as a function of experimentally tractable variables, which we calculate for the case of the phototropic response of
Arabidopsis
hypocotyls. All together, our model enables us to predict tropic responses to time-varying stimuli, manifested in temporal integration phenomena, and sets the stage for the incorporation of additional effects such as multiple stimuli, gravitational sagging, etc.
Opportunities and challenges of circulating biomarkers in neuroblastoma
Authors: Trigg Ricky M. , Shaw Jacqui A. , Turner Suzanne D.
Published: May 2019

Molecular analysis of nucleic acid and protein biomarkers is becoming increasingly common in paediatric oncology for diagnosis, risk stratification and molecularly targeted therapeutics. However, many current and emerging biomarkers are based on analysis of tumour tissue, which is obtained through invasive surgical procedures and in some cases may not be accessible. Over the past decade, there has been growing interest in the utility of circulating biomarkers such as cell-free nucleic acids, circulating tumour cells and extracellular vesicles as a so-called liquid biopsy of cancer. Here, we review the potential of emerging circulating biomarkers in the management of neuroblastoma and highlight challenges to their implementation in the clinic.
Match and mismatch between dietary switches and microbial partners in plant sap-feeding insects
Authors: Bell-Roberts Louis , Douglas Angela E. , Werner Gijsbert D. A.
Published: May 2019

Some animal groups associate with the same vertically transmitted microbial symbionts over extended periods of evolutionary time, punctuated by occasional symbiont switches to different microbial taxa. Here we test the oft-repeated suggestion that symbiont switches are linked with host diet changes, focusing on hemipteran insects of the suborder Auchenorrhyncha. These insects include the only animals that feed on plant xylem sap through the life cycle, as well as taxa that feed on phloem sap and plant parenchyma cells. Ancestral state reconstruction provides strong statistical support for a xylem feeding auchenorrhynchan ancestor bearing the dual symbiosis with the primary symbiontSulcia(Bacteroidetes) and companion symbiont ‘β-Sym’ (β-proteobacteria). We identified seven dietary transitions from xylem feeding (six to phloem feeding, one to parenchyma feeding), but no reversions to xylem feeding; five evolutionary losses ofSulcia, including replacements by yeast symbionts, exclusively in phloem/parenchyma-feeding lineages; and 14–15 losses of β-Sym, including nine transitions to a different bacterial companion symbiont. Our analysis indicates that, although companion symbiont switching is not associated with shifts in host diet,Sulciais probably required for xylem-feeding. Furthermore, the ancestral auchenorrhynchan bearingSulciaand β-Sym probably represents the sole evolutionary origin of xylem feeding in the animal kingdom.
Predator coevolution and prey trait variability determine species coexistence
Authors: Scheuerl Thomas , Cairns Johannes , Becks Lutz , Hiltunen Teppo
Published: May 2019

Predation is one of the key ecological mechanisms allowing species coexistence and influencing biological diversity. However, ecological processes are subject to contemporary evolutionary change, and the degree to which predation affects diversity ultimately depends on the interplay between evolution and ecology. Furthermore, ecological interactions that influence species coexistence can be altered by reciprocal coevolution especially in the case of antagonistic interactions such as predation or parasitism. Here we used an experimental evolution approach to test for the role of initial trait variation in the prey population and coevolutionary history of the predator in the ecological dynamics of a two-species bacterial community predated by a ciliate. We found that initial trait variation both at the bacterial and ciliate level enhanced species coexistence, and that subsequent trait evolutionary trajectories depended on the initial genetic diversity present in the population. Our findings provide further support to the notion that the ecology-centric view of diversity maintenance must be reinvestigated in light of recent findings in the field of eco-evolutionary dynamics.
Habituation underpins preference for mates with novel phenotypes in the guppy
Authors: Daniel M. J. , Koffinas L. , Hughes K. A.
Published: May 2019

Populations harbour enormous genetic diversity in ecologically important traits. Understanding the processes that maintain this variation is a long-standing challenge in evolutionary biology. Recent evidence indicates that a mating preference for novel sexual signals can be a powerful force maintaining genetic diversity. However, the proximate underpinnings of this preference, and its generality, remain unclear. Here, we test the hypothesis that preference for novel sexual signals is underpinned by habituation, a nearly ubiquitous form of learning whereby individuals become less responsive to repetitive stimuli. We use the Trinidadian guppy (
Poecilia reticulata
), in which male colour patterns are diverse yet heritable. We show that repeated exposure to males with a given colour pattern reduces female interest in males with that pattern, and that interest recovers following brief isolation. These results fulfil two core criteria of habituation: responsiveness decline and spontaneous recovery. To distinguish habituation from sensory adaptation and fatigue, we also demonstrate stimulus specificity and dishabituation. These results provide the first evidence that habituation causes a preference for novel sexual signals, addressing the mechanistic underpinnings of this mating preference. Given the pervasiveness of habituation among taxa and sensory contexts, our findings suggest that preference for novelty may play an underappreciated role in mate choice and the maintenance of genetic variation.
Structurally assisted super black in colourful peacock spiders
Authors: McCoy Dakota E. , McCoy Victoria E. , Mandsberg Nikolaj K. , Shneidman Anna V. , Aizenberg Joanna , Prum Richard O. , Haig David
Published: May 2019

Male peacock spiders (
Maratus
, Salticidae) compete to attract female mates using elaborate, sexually selected displays. They evolved both brilliant colour and velvety black. Here, we use scanning electron microscopy, hyperspectral imaging and finite-difference time-domain optical modelling to investigate the deep black surfaces of peacock spiders. We found that super black regions reflect less than 0.5% of light (for a 30° collection angle) in
Maratus speciosus
(0.44%) and
Maratus karrie
(0.35%) owing to microscale structures. Both species evolved unusually high, tightly packed cuticular bumps (microlens arrays), and
M. karrie
has an additional dense covering of black brush-like scales atop the cuticle. Our optical models show that the radius and height of spider microlenses achieve a balance between (i) decreased surface reflectance and (ii) enhanced melanin absorption (through multiple scattering, diffraction out of the acceptance cone of female eyes and increased path length of light through absorbing melanin pigments). The birds of paradise (Paradiseidae), ecological analogues of peacock spiders, also evolved super black near bright colour patches. Super black locally eliminates white specular highlights, reference points used to calibrate colour perception, making nearby colours appear brighter, even luminous, to vertebrates. We propose that this pre-existing, qualitative sensory experience—‘sensory bias’—is also found in spiders, leading to the convergent evolution of super black for mating displays in jumping spiders.
Imperfect camouflage: how to hide in a variable world?
Authors: Hughes Anna , Liggins Eric , Stevens Martin
Published: May 2019

Camouflage is an important anti-predator strategy for many animals and is traditionally thought of as being tightly linked to a specific visual background. While much work focuses on optimizing camouflage against one background, this may not be relevant for many species and contexts, as animals may encounter many different habitats throughout their lives due to temporal and spatial variation in their environment. How should camouflage be optimized when an animal or object is seen against multiple visual backgrounds? Various solutions may exist, including colour change to match new environments or use of behaviour to maintain crypsis by choosing appropriate substrates. Here, we focus on a selection of approaches under a third alternative strategy: animals may adopt (over evolution) camouflage appearances that represent an optimal solution against multiple visual scenes. One approach may include a generalist or compromise strategy, where coloration matches several backgrounds to some extent, but none closely. A range of other camouflage types, including disruptive camouflage, may also provide protection in multiple environments. Despite detailed theoretical work determining the plausibility of compromise camouflage and elucidating the conditions under which it might evolve, there is currently mixed experimental evidence supporting its value and little evidence of it in natural systems. In addition, there remain many questions including how camouflage strategies should be defined and optimized, and how they might interact with other types of crypsis and defensive markings. Overall, we provide a critical overview of our current knowledge about how camouflage can enable matching to multiple backgrounds, discuss important challenges of working on this question and make recommendations for future research.
Coagulase gene polymorphisms of Staphylococcus aureus isolates from patients at Kosti Teaching Hospital, Sudan
Authors: Ibrahim Omer Mohammed Ali , Bilal Naser Eldin , Azoz Mohammed E. H. , Eltahir Hanan B.
Published: May 2019

Background.

Staphylococcus aureus

is a common cause of nosocomial infections. Epidemiological typing of

S. aureus

enables control of its spread. The objective of this study was to investigate coagulase gene polymorphisms of

S. aureus

isolated from patients at Kosti Hospital in Sudan.

Methods. In total, 110

S. aureus

isolates were recovered from 110 patients who were enrolled in the study.

S. aureus

strains were isolated on blood agar and MacConkey agar and then identified by conventional tests. Resistance to methicillin was determined by detection of the mecA gene. Polymorphism in the coagulase gene (coa) was investigated using PCR followed by AluI RFLP analysis.

Results. Methicillin-resistant

S. aureus

accounted for 62/110 (56 %) of the isolates. PCR of the coa gene showed two different amplicons, one of 680 bp detected in 83/110 (75.5 %) of the isolates and one of 790 bp detected in 27/110 (24.5 %). When digested with the AluI enzyme, the 790 bp amplicon resulted in three restriction fragments of 500, 210 and 80 bp (coa1). Restriction of the 680 bp amplicon gave two patterns; the first (coa2) was found in 22/110 (20 %) of the isolates and showed four fragments of 210, 210, 180 and 80 bp, and the second (coa3) was found in 61/110 (55.5 %) and revealed three fragments of 390, 210 and 80 bp. Most of the coa3 isolates (75.4%) were methicillin-resistant.

Conclusion. Three polymorphic genotypes of

S. aureus

were identified in patients at Kosti Hospital. The coa3 genotype was the predominant one and was mostly detected in methicillin-resistant isolates.
A pretectal command system controls hunting behaviour
Authors: Antinucci Paride , Folgueira Mónica , Bianco Isaac H.
Published: May 2019

For many species, hunting is an innate behaviour that is crucial for survival, yet the circuits that control predatory action sequences are poorly understood. We used larval zebrafish to identify a command system that controls hunting. By combining calcium imaging with a virtual hunting assay, we identified a discrete pretectal region that is selectively active when animals initiate hunting. Targeted genetic labelling allowed us to examine the function and morphology of individual cells and identify two classes of pretectal neuron that project to ipsilateral optic tectum or the contralateral tegmentum. Optogenetic stimulation of single neurons of either class was able to induce sustained hunting sequences, in the absence of prey. Furthermore, laser ablation of these neurons impaired prey-catching and prevented induction of hunting by optogenetic stimulation of the anterior-ventral tectum. In sum, we define a specific population of pretectal neurons that functions as a command system to drive predatory behaviour.

Key findings

Pretectal neurons are recruited during hunting initiation

Optogenetic stimulation of single pretectal neurons can induce predatory behaviour

Ablation of pretectal neurons impairs hunting

Pretectal cells comprise a command system controlling hunting behaviour
Compromised function of the ESCRT pathway promotes endolysosomal escape of tau seeds and propagation of tau aggregation
Authors: Chen John J. , Nathaniel Diane L. , Raghavan Preethi , Nelson Maxine , Tian Ruilin , Tse Eric , Hong Jason Y. , See Stephanie K. , Mok Sue-Ann , Hein Marco Y. , Southworth Daniel R. , Grinberg Lea T. , Gestwicki Jason E. , Leonetti Manuel D. , Kampmann Martin
Published: May 2019

Intercellular propagation of protein aggregation is emerging as a key mechanism in the progression of several neurodegenerative diseases, including Alzheimer’s Disease and frontotemporal dementia. However, we lack a systematic understanding of the cellular path-ways controlling prion-like propagation. To uncover such pathways, we performed CRISPR interference (CRISPRi) screens in a human cell-based model of propagation of tau aggregation. Our screens uncovered that knockdown of several components of the ESCRT machinery, including CHMP6, or CHMP2A in combination with CHMP2B (a gene linked to familial fronto-temporal dementia), promote propagation of tau aggregation. We found that knockdown of these genes caused damage to endolysosomal membranes, consistent with a role for the ESCRT pathway in endolysosomal membrane repair. Leakiness of the endolysosomal compartment significantly enhanced prion-like propagation of tau aggregation, likely by making tau seeds more available to pools of cytoplasmic tau. Together, these findings suggest that endolysosomal escape is a critical step in tau propagation.
Molecular basis of EMRE-dependence of the human mitochondrial calcium uniporter
Authors: MacEwen Melissa J.S. , Markhard Andrew L. , Bozbeyoglu Mert , Bradford Forrest , Goldberger Olga , Mootha Vamsi K. , Sancak Yasemin
Published: May 2019

The mitochondrial uniporter is calcium-activated calcium channel complex critical for cellular signaling and bioenergetics. MCU, the pore-forming subunit of the uniporter, contains two transmembrane domains and is found in all major eukaryotic taxa. In amoeba and fungi, MCU homologs are sufficient to form a functional calcium channel, whereas human MCU exhibits a strict requirement for the metazoan-specific, single-pass transmembrane protein EMRE for conductance. Here, we exploit this evolutionary divergence to decipher the molecular basis of the human MCU’s dependence on EMRE. By systematically generating chimeric proteins that consist of EMRE-independentD. discoideumMCU (DdMCU) andH. sapiensMCU (HsMCU), we converged on a stretch of 10 amino acids in DdMCU that can be transplanted to HsMCU to render it EMRE-dependent. We call this region in human MCU the EMRE-dependence domain (EDD). Crosslinking experiments show that HsEMRE directly interacts with MCU at both of its transmembrane domains as well as the EDD. Based on previously published structures of fungal MCU homologs, the EDD segment is located distal to the calcium pore’s selectivity filter and appears flexible. We propose that EMRE stabilizes EDD of MCU, permitting both channel opening and calcium conductance
Septin 2/6/7 complexes tune microtubule plus end growth and EB1 binding in a concentration- and filament-dependent manner
Authors: Nakos Konstantinos , Radler Megan R. , Spiliotis Elias T.
Published: May 2019

Septins are filamentous GTP-binding proteins, which affect microtubule (MT) dependent functions including membrane trafficking and cell division, but their precise role in MT dynamics is poorly understood. Here, in vitro reconstitution of MT dynamics with SEPT2/6/7, the minimal subunits of septin heteromers, shows that SEPT2/6/7 has a biphasic concentration-dependent effect on MT growth. Lower concentrations of SEPT2/6/7 enhance MT plus end growth and elongation, while higher and intermediate concentrations inhibit and pause plus end growth, respectively. We show that SEPT2/6/7 has a 1.5-fold preference for GTP-over GDP-bound MT lattice, and competes with EB1 for binding to GTPγS-stabilized MTs, which mimic the EB1-preferred GDP-Pi state of polymerized tubulin. Strikingly, SEPT2/6/7 triggers EB1 dissociation from plus end tips in cis by binding to the MT lattice and in trans when MT plus ends collide with SEPT2/6/7 filaments. At these intersections, SEPT2/6/7 filaments were more potent barriers than actin filaments in pausing MT growth and dissociating EB1 in vitro and in live cells. These data demonstrate that SEPT2/6/7 complexes and filaments can directly impact MT plus end growth and the tracking of plus end-binding proteins, and thereby may facilitate the capture of MT plus ends at intracellular sites of septin enrichment.

Highlight Summary for eTOC

Knowledge of septin roles in MT dynamics is poor and confounded by knockdown studies. Here, in vitro reconstitution assays show concentration-dependent effects of SEPT2/6/7 on MT plus end growth, pausing and EB1 tracking. We found that SEPT2/6/7 filaments are potent than actin in pausing MT growth and dissociating EB1 from intersecting plus ends.
Cryo-EM structure of the MinCD copolymeric filament from Pseudomonas aeruginosa at 3.1 Å resolution
Authors: Szewczak-Harris Andrzej , Wagstaff James , Löwe Jan
Published: May 2019

Positioning of the division site in many bacterial species relies on the MinCDE system, which prevents the cytokinetic Z-ring from assembling anywhere but the mid-cell, through an oscillatory diffusion-reaction mechanism. MinD dimers bind to membranes and, via their partner MinC, inhibit the polymerisation of cell division protein FtsZ into the Z-ring. MinC and MinD form polymeric assemblies in solution and on cell membranes. Here, we report the high-resolution cryo-EM structure of the copolymeric filaments of Pseudomonas aeruginosa MinCD. The filaments consist of three protofilaments made of alternating MinC and MinD dimers. The MinCD protofilaments are almost completely straight and assemble as single protofilaments on lipid membranes, which we also visualised by cryo-EM.
Acute sleep deprivation and the selective consolidation of emotional memories
Authors: Vargas Ivan , Payne Jessica D. , Muench Alexandria , Kuhlman Kate R. , Lopez-Duran Nestor L.
Published: May 2019

Research suggests that sleep preferentially consolidates the negative aspects of memories at the expense of the neutral aspects. However, the mechanisms by which sleep facilitates this emotional memory trade-off remain unknown. Although active processes associated with sleep-dependent memory consolidation have been proposed to underlie this effect, this trade-off may also be modulated by non-sleep-related processes, such as the circadian factors, stress-related factors, and/or mood congruent context effects involved in sleep deprivation. We sought to examine the potential role of these factors by randomizing 39 young adults into either a total sleep deprivation condition (26 consecutive hours awake) or a sleep condition (8 h sleep opportunity). Replicating the emotional memory trade-off effect, negative objects were better remembered than neutral objects or background images. However, in spite of generally worse memory performance (for neutral and background information), sleep-deprived participants showed similar recognition rates for negative emotional memories relative to participants who were given a full night of sleep.
Productivity and production risk effects of adopting drought-tolerant maize varieties in Zambia
Authors: Amondo Emily , Simtowe Franklin , Rahut Dil Bahadur , Erenstein Olaf
Published: May 2019

Purpose

Productivity and production risks affect the use of agricultural production practices and inputs, particularly in developing countries. This paper aims to investigate the effects of adopting drought-tolerant maize varieties (DTMVs) on farm productivity, yield variance and downside risk exposure of maize growing households of Zambia.

Design/methodology/approach

The study uses household survey data collected from 11 maize producing districts of Eastern, Southern and Copperbelt provinces of Zambia using a structured questionnaire. The Antle’s flexible moment-based approach was used in specifying, estimating and testing a stochastic production function. The study further applied an endogenous switching regression model to control for both observable and unobservable sources of bias.

Findings

The study revealed that DTMV adoption increases maize yield by 15 per cent and reduces the risk of crop failure: reducing yield variance by 38 per cent and exposure to downside risk by 36 per cent.

Originality/value

This study establishes the benefits of DTMV adoption in Zambia with regards to productivity, yield stability and downside risk in the face of climate change. Results from this study underscore the need for more concerted efforts to scale-out DTMVs for both maize productivity enhancement and for risk mitigation against weather shocks.
Perceptions of climate change and water availability in the Mediterranean tourist sector
Authors: Torres-Bagur Maria , Ribas Palom Anna , Vila-Subirós Josep
Published: May 2019

Purpose

The purpose of this paper is understand these perceptions and identify main problems associated to climate change in order to design effective mitigation and adaptation strategies to guarantee the sustainability of tourism and natural resources. The Mediterranean basin is a leading international tourist destination and one that is particularly vulnerable to the effects of climate change. Although these effects are largely known, in-depth studies of how they and the associated risks are perceived by key tourism stakeholders have not been performed.

Design/methodology/approach

Interviews were held with 31 hotels, campsites and rural lodgings in the Muga River basin in north-east Catalonia, in which both owners and managers were asked about their perceptions of climate change, effects and countermeasures.

Findings

Perceptions of climate change and its effects varied according to the type of establishment and location (coast, cities or inland). Significant differences were observed for perceptions of how responsibilities for implementing mitigation and adaptation measures to counter the effects of climate change, including water shortages, should be shared out between the main agents with an interest in guaranteeing the sustainability of tourism, namely, government bodies, tourist establishments and clients. The predominant opinion, however, was that the bulk of the responsibility should lie with government bodies.

Practical implications

Only when those responsible for running tourist establishments are aware of the risks of climate change, it will be possible to design and implement effective short-, medium- and long-term strategies aimed at strengthening the resilience of the tourist industry.

Originality/value

The originality of this study lies in its novel methodology and approach, which involved analyzing perceptions of climate change, including water shortages and its effects among owners and managers of different types of tourist accommodation establishments in distinct parts of the same area.