bluuebunny/crossref_metadata_2025 huggingface dataset:
Induction of Adaptive Immunity Leads to Nigrostriatal Disease Progression in MPTP Mouse Model of Parkinson’s Disease
Authors: Chandra Goutam , Roy Avik , Rangasamy Suresh B. , Pahan Kalipada
Published: April 2017

Although the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model is the most widely used animal model for Parkinson’s disease (PD), it is known that nigrostriatal pathologies do not persist in the acute MPTP mouse model. This study highlights the importance of adaptive immunity in driving persistent and progressive disease in acute MPTP-intoxicated mice. Although marked infiltration of T cells into the nigra was found on 1 d of MPTP insult, T cell infiltration decreased afterward, becoming normal on 30 d of insult. Interestingly, twice-weekly supplementation of RANTES and eotaxin, chemokines that are involved in T cell trafficking, drove continuous T cell infiltration to the nigra and incessant glial inflammation. Supplementation of RANTES and eotaxin was also associated with the induction of nigral α-synuclein pathology, persistent loss of dopaminergic neurons and striatal neurotransmitters, and continuous impairment of motor functions in MPTP-intoxicated mice. In contrast, supplementation of TNF-α and IL-1β, widely studied proinflammatory cytokines, did not induce persistent disease in MPTP-insulted mice. Our results suggest that induction of adaptive immunity by RANTES and eotaxin could hold the key for driving persistent nigrostriatal pathologies in the MPTP mouse model, and that targeting these factors may halt disease progression in PD patients.
Adverse Selection in Health Insurance Coverage of High-Cost Cures
Authors: Melmeyer Paul
Published: April 2017

The following paper examines adverse selection concerns facing health insurance companies from the coverage of high-cost, but highly-effective, cures for chronic diseases. This problem has arisen over the past several years with the development of Sovaldi, a cure for hepatitis C. However, it will become more prevalent as more expensive cures, particularly gene therapies, are developed and come to market. Health insurers, when deciding to cover the expensive cures, incur the risk that a disproportionate number of high-cost individuals will enroll in their plan while they are ill, but leave once they are cured and healthy. This adverse selection problem may lead health insurers to avoid risking this possibility, and as a result not cover the cures at all. Policymakers have posited several solutions to address this market failure. One potential policy solution is the establishment of a risk-stabilization program for insurance plans that cover these therapies. This risk-stabilization program would de-risk the potential adverse selection and allow chronically ill patients to access revolutionary, curative therapies. A second potential policy solution is the institution of annuity-like “pay-for-performance” models in which insurers pay for expensive but curative treatments over several years, contingent on the treatment’s performance.
Venous function after pharmaco-mechanical thrombolysis for extensive ileofemoral deep vein thrombosis: Six-year outcome
Authors: Greeff Wim , Van Marle Jacobus , Dehghan-Dehnavi Ali
Published: April 2017

No abstract available.
Diagnostic reference levels for paediatric computed tomography
Authors: Vawda Zakariya
Published: April 2017

No abstract available.
The sensitivity and specificity of radiological features of Hirschsprung’s disease in a cohort of South African children
Authors: Vlok Sucari S.C. , Moore Sam W. , Schubert Pawel T. , Pitcher Richard D.
Published: April 2017

No abstract available.
Poincaré Lemma on Quaternion-like Heisenberg Groups
Authors: Chang Der-Chen , Yang Nanping , Wu Hsi-Chun
Published: April 2017

For smooth functions a1, a2, a3, a4 on a quaternion Heisenberg group, we characterize the existence of solutions of the partial differential operator system X1f = a1, X2f = a2, X3f = a3, and X4f = a4. In addition, a formula for the solution function f is deduced, assuming solvability of the system.
A Multiplier Theorem on Anisotropic Hardy Spaces
Authors: Wang Li-an Daniel
Published: April 2017

We present a multiplier theorem on anisotropic Hardy spaces. When m satisfies the anisotropic, pointwise Mihlin condition, we obtain boundedness of the multiplier operator Tm: → , for the range of p that depends on the eccentricities of the dilation A and the level of regularity of a multiplier symbol m. This extends the classical multiplier theorem of Taibleson andWeiss.
Lower matching conjecture, and a new proof of Schrijver's and Gurvits's theorems
Authors: Csikvári Péter
Published: April 2017

Friedland's Lower Matching Conjecture asserts that if

G

is a

d

-regular bipartite graph on

\nu(G)=2n

vertices, and

m_k(G)

denotes the number of matchings of size

k

, then

m_k(G )\geq {n \choose k}^2\left(\frac{d-p}{d}\right)^{n(d-p)}(dp)^{np},

where

p=\frac{k}{n}

. When

p=1

, this conjecture reduces to a theorem of Schrijver which says that a

d

-regular bipartite graph on

\nu(G)=2n

vertices has at least

\left(\frac{(d-1)^{d-1}}{d^{d-2}}\right)^n

perfect matchings. L. Gurvits proved an asymptotic version of the Lower Matching Conjecture, namely he proved that

\frac{\mathrm {ln}\: m_k(G)}{\nu (G)} \geq \frac{1}{2}\left(p \: \mathrm {ln} \left(\frac{d}{p}\right)+(d-p) \:\mathrm {ln} \left(1-\frac{p}{d}\right)-2(1-p) \:\mathrm {ln} (1-p)\right)+o_{\nu (G)}(1).

In this paper, we prove the Lower Matching Conjecture. In fact, we will prove a slightly stronger statement which gives an extra

c_p\sqrt{n}

factor compared to the conjecture if

p

is separated away from

0

and

1

, and is tight up to a constant factor if

p

is separated away from

1

. We will also give a new proof of Gurvits's and Schrijver's theorems, and we extend these theorems to

(a,b)

-biregular bipartite graphs.
The tracial Hahn–Banach theorem, polar duals, matrix convex sets, and projections of free spectrahedra
Authors: Helton J. William , Klep Igor , McCullough Scott
Published: April 2017

This article investigates matrix convex sets. It introduces tracial analogs, which we call contractively tracial convex sets. Critical in both contexts are completely positive (cp) maps. While unital cp maps tie into matrix convex sets, trace preserving cp (CPTP) maps tie into contractively tracial sets. CPTP maps are sometimes called quantum channels and are central to quantum information theory.

Free convexity is intimately connected with Linear Matrix Inequalities (LMIs)

L(x) = A_0 + A_1 x_1 + \cdots + A_g x_g \succeq 0

and their matrix convex solution sets

\{ X : L(X \succeq 0\}

, called
free spectrahedra
. The Effros–Winkler Hahn–Banach Separation Theorem for matrix convex sets states that matrix convex sets are solution sets of LMIs with operator coefficients. Motivated in part by cp interpolation problems, we develop the foundations of convex analysis and duality in the tracial setting, including tracial analogs of the Effros–Winkler Theorem.

The projection of a free spectrahedron in

g+h

variables to

g

variables is a matrix convex set called a
free spectrahedrop
. As a class, free spectrahedrops are more general than free spectrahedra, but at the same time more tractable than general matrix convex sets. Moreover, many matrix convex sets can be approximated from above by free spectrahedrops. Here a number of fundamental results for spectrahedrops and their polar duals are established. For example, the free polar dual of a free spectrahedrop is again a free spectrahedrop. We also give a Positivstellensatz for free polynomials that are positive on a free spectrahedrop.
“Misfits” in Fin-de-Siècle France and Italy
Authors: Ashley Susan A.
Published: April 2017

As the 19th century drew to a close, France and Italy experienced an explosion of crime, vagrancy, insanity, neurosis and sexual deviance. “Misfits” in Fin-de-Siècle France and Italy examines how the raft of self-appointed experts that subsequently emerged tried to explain this aberrant behavior and the many consequences this had.

Susan A. Ashley considers why these different phenomena were understood to be interchangeable versions of the same inborn defects. The book looks at why specialists in newly-minted disciplines in medicine and the social sciences, such as criminology, neurology and sexology, all claimed that biological flaws – some inherited and some arising from illness or trauma – made it impossible for these ‘misfits’ to adapt to modern life. Ashley then goes on to analyse the solutions these specialists proposed, often distinguishing between born deviants who belonged in asylums or prisons and ‘accidental misfits’ who deserved solidarity and social support through changes to laws relating to issues like poverty and unemployment.

The study draws on a comprehensive examination of contemporary texts and features the work of leading authorities like Cesare Lombroso, Jean-Martin Charcot, and Théodule Ribot, as well as investigators less known now but influential at the time. The comparative aspect also interestingly shows that experts collaborated closely across national and disciplinary borders, employed similar methods and arrived at common conclusions.

This is a valuable study for all social and cultural historians of France and Italy and anyone interested in knowing more about the history of medicine in modern Europe.
Movies with Meaning
Authors: Shaw Daniel
Published: April 2017

This book pairs close readings of some of the classic writings of existentialist philosophers with interpretations of films that reveal striking parallels to each of those texts, demonstrating their respective philosophies in action. Individual chapters include significant excerpts from the original texts being discussed and illustrated. Pairings cover Schopenhauer and Waking Life, Stirner and Hud, Kierkegaard and Winter Light, Nietzsche and The Fountainhead, Heidegger, Blade Runner and The Thin Red Line, Camus, Leaving Las Vegas and Missing, Sartre, Husbands and Wives, and Michael Collins, de Beauvoir and Revolutionary Road, and Foucault and One Flew Over the Cuckoo’s Nest.

Movies with Meaning offers a clear and insightful examination of the relationships between existential philosophers and film, providing both digests of their most significant texts and cinematic illustrations of what each had in mind. For the first time in one place, this book analyses the implications for film of the perspectives of a wide array of the most significant existentialist thinkers. Organized chronologically, like most existentialism anthologies, this is an ideal textbook for an intermediate level existentialism course, or as a companion to a selection of primary texts.
Aesthetics, Arts, and Politics in a Global World
Authors: Herwitz Daniel
Published: April 2017

A different set of purposes define culture today than those that preoccupied the world in the immediate decades of decolonization. Focusing on art and music in diverse parts of the world, Daniel Herwitz explores a world that has largely shifted from the earlier days of nationalism, decolonization and cultural exclusion, to one of global markets and networks.

Using examples from India and Mexico to South Africa, Australia and China, Herwitz argues that the cultural politics and art being produced in these places are now post- postcolonial. Where the postcolonial downplayed formerly Eurocentric forms and celebrated art with national consciousness, the rules for 21st century cultural authenticity are quickly disappearing. Young people think of themselves in relation to global culture rather than nation-building; the project of producing a new and modern art for the incipient and rising postcolonial nation is out of date.

By examining the shift in which art accesses the past and the rise of trends such as hitching consumer culture to celebrity forms and branding, Herwitz’s original and engaging exploration of contemporary art captures the ways in which art has given way to a new form of production, altering everything from the role of tradition and heritage in contemporary art to the terms of its vision and circulation.
Compact Cinematics
Authors: Hesselberth Pepita , Poulaki Maria
Published: April 2017

Compact Cinematics challenges the dominant understanding of cinema to focus on the various compact, short, miniature, pocket-sized forms of cinematics that have existed from even before its standardization in theatrical form, and in recent years have multiplied and proliferated, taking up an increasingly important part of our everyday multimedia environment. Short films or micro-narratives, cinematic pieces or units re-assembled into image archives and looping themes, challenge the concepts that have traditionally been used to understand cinematic experience, like linear causality, sequentiality, and closure, and call attention to complex and modular forms of cinematic expression and perception. Such forms, in turn, seem to meet the requirements of digital convergence, which has pushed the development of more compact and mobile hardware for the display and use of audiovisual content on laptops, smartphones, and tablets. Meanwhile, contemporary economies of digital content acquisition, filing, and sharing equally require the shrinking of cinematic content for it to be recorded, played, projected, distributed, and installed with ease and speed. In this process, cinematic experience is shortened and condensed as well, so as to fit the late-capitalist attention economy. The essays in this volume ask what this changed technical, socio-economic and political situation entails for the aesthetics and experience of contemporary cinematics, and call attention to different concepts, theories and tools at our disposal to analyze these changes.
Urbanization-induced urban heat island and aerosol effects on climate extremes in the Yangtze River Delta region of China
Authors: Zhong Shi , Qian Yun , Zhao Chun , Leung Ruby , Wang Hailong , Yang Ben , Fan Jiwen , Yan Huiping , Yang Xiu-Qun , Liu Dongqing
Published: April 2017

Abstract. The WRF-Chem model coupled with a single-layer urban canopy model (UCM) is integrated for 5 years at convection-permitting scale to investigate the individual and combined impacts of urbanization-induced changes in land cover and pollutant emissions on regional climate in the Yangtze River Delta (YRD) region in eastern China. Simulations with the urbanization effects reasonably reproduced the observed features of temperature and precipitation in the YRD region. Urbanization over the YRD induces an urban heat island (UHI) effect, which increases the surface temperature by 0.53 °C in summer and increases the annual heat wave days at a rate of 3.7 d yr−1 in the major megacities in the YRD, accompanied by intensified heat stress. In winter, the near-surface air temperature increases by approximately 0.7 °C over commercial areas in the cities but decreases in the surrounding areas. Radiative effects of aerosols tend to cool the surface air by reducing net shortwave radiation at the surface. Compared to the more localized UHI effect, aerosol effects on solar radiation and temperature influence a much larger area, especially downwind of the city cluster in the YRD. Results also show that the UHI increases the frequency of extreme summer precipitation by strengthening the convergence and updrafts over urbanized areas in the afternoon, which favor the development of deep convection. In contrast, the radiative forcing of aerosols results in a surface cooling and upper-atmospheric heating, which enhances atmospheric stability and suppresses convection. The combined effects of the UHI and aerosols on precipitation depend on synoptic conditions. Two rainfall events under two typical but different synoptic weather patterns are further analyzed. It is shown that the impact of urban land cover and aerosols on precipitation is not only determined by their influence on local convergence but also modulated by large-scale weather systems. For the case with a strong synoptic forcing associated with stronger winds and larger spatial convergence, the UHI and aerosol effects are relatively weak. When the synoptic forcing is weak, however, the UHI and aerosol effects on local convergence dominate. This suggests that synoptic forcing plays a significant role in modulating the urbanization-induced land-cover and aerosol effects on individual rainfall event. Hence precipitation changes due to urbanization effects may offset each other under different synoptic conditions, resulting in little changes in mean precipitation at longer timescales.
Leipzig Ice Nucleation chamber Comparison (LINC): Inter-comparison of four online ice nucleation counters
Authors: Burkert-Kohn Monika , Wex Heike , Welti André , Hartmann Susan , Grawe Sarah , Hellner Lisa , Herenz Paul , Atkinson James D. , Stratmann Frank , Kanji Zamin A.
Published: April 2017

Abstract. Ice crystal formation in atmospheric clouds has a strong effect on precipitation, cloud lifetime, cloud radiative properties and thus the global energy budget. Primary ice formation above 235 K is initiated by nucleation on seed aerosol particles called ice nucleating particles (INPs). Instruments that measure the ice nucleating potential of aerosol particles in the atmosphere need to be able to accurately quantify ambient INP concentrations. In the last decade several instruments have been developed to investigate the ice nucleating properties of aerosol particles and to measure ambient INP concentrations. Therefore, there is a need for inter-comparisons to ensure instrument differences are not interpreted as scientific findings. In this study, we inter-compare the results from parallel measurements using four online ice nucleation chambers. Seven different aerosol types are tested including untreated and acid treated mineral dust (microcline – a K-feldspar – and kaolinite), as well as birch pollen washing waters. Experiments exploring heterogeneous ice nucleation above and below water saturation are performed to cover the whole range of thermodynamic conditions that can be investigated with the inter-compared chambers. The Leipzig Aerosol Cloud Interaction Simulator (LACIS) and the Portable Immersion Mode Cooling chAmber coupled to the Portable Ice Nucleation Chamber (PIMCA-PINC) performed measurements in the immersion freezing mode. Additionally two continuous flow diffusion chambers (CFDCs) PINC and the Spectrometer for Ice Nuclei (SPIN) are used to perform measurements below and just above water saturation nominally presenting deposition nucleation and condensation freezing. The results of LACIS and PIMCA-PINC agree well over the whole range of measured frozen fractions (FFs) and temperature. In general PINC and SPIN compare well and the observed differences are explained by ice crystal growth and different residence times in the chamber. To study the mechanisms responsible for ice nucleation in the four instruments, FF (from LACIS and PIMCA-PINC) and activated fraction, AF (from PINC and SPIN) are compared. Measured FFs are up to a factor of three higher than AFs, but not consistent for all aerosol types and temperatures investigated. It showed that measurements from CFDCs cannot be assumed to produce the same results as those instruments exclusively measuring immersion freezing. Instead the need to apply a scaling factor to CFDCs operating above water saturation has to be considered to allow comparison with immersion freezing devices. Our results provide further awareness on factors such as the importance of dispersion methods and the quality of particle size-selection for inter-comparing online INP counters.
Technical note: an economical apparatus for the observation and harvest of mineral precipitation experiments with light microscopy
Authors: Crosby Chris H. , Bailey Jake V.
Published: April 2017

Abstract. We describe a small-scale, reusable, and low-cost double-diffusion setup that allows microscopic observation over time for use in mineral precipitation experiments that use organic polymers as a matrix. The setup uniquely accommodates changes in solution chemistry during the course of an experiment and facilitates easy harvesting of the precipitates for subsequent analysis.
PEDAGOGIA DO ESPORTE: SINALIZAÇÃO PARA A AVALIAÇÃO FORMATIVA DA APRENDIZAGEM
Authors: Leonardi Thiago José , Galatti Larissa Rafaela , Scaglia Alcides José , De Marco Ademir , Paes Roberto Rodrigues
Published: April 2017

Diante da carência de estudos que discutam epistemologicamente avaliação da aprendizagem no âmbito da Pedagogia do Esporte, este ensaio se propõe a descrever a avaliação da aprendizagem em sua perspectiva formativa e autêntica, a elencar instrumentos existentes no campo da Pedagogia do Esporte e, por fim, a sinalizar desafios para a construção de futuros instrumentos. Em geral, estudos denotam caráter somativo na utilização dos instrumentos existentes. Logo, defende-se a necessidade de novos instrumentos de avaliação que a entendam em seu caráter educativo e formativo, focados na avaliação integral de quem joga, além das competências para o jogo.
A FORMAÇÃO DE JOVENS FUTEBOLISTAS ALÉM DAS QUATRO LINHAS: UMA ANÁLISE SOB A ÓTICA DOS TÉCNICOS DE BRASIL E PORTUGAL
Authors: Do Prado Szeremeta Thaynara , Szmyczak Conde Juan Henrique , Barata Figueiredo António José , De Barros Gonçalves Carlos Eduardo , Cavichiolli Fernando Renato
Published: April 2017

O objetivo deste estudo foi analisar o processo de formação de jovens futebolistas sob a perspectiva de técnicos de Brasil e Portugal. Oito técnicos participaram do estudo, sendo quatro brasileiros e quatro portugueses. Foi utilizada a entrevista semiestruturada, da qual emergiram quatro categorias. O processo de formação de atletas é diferente entre os   países. O contexto social e pedagógico no Brasil passa por diversos departamentos específicos antes de chegar ao técnico, por outro lado, em Portugal o técnico tem mais proximidade com as questões sociais que envolvem os atletas. Uma realidade pode   aprender com a outra, a fim de que os atletas se desenvolvam tecnicamente, mas que também desenvolvam outras competências no caso de insucesso no futebol.
Reviewer Acknowledgements for International Journal of Chemistry, Vol. 9, No. 2
Authors: John Albert
Published: April 2017

International Journal of Chemistry wishes to acknowledge the following individuals for their assistance with peer review of manuscripts for this issue. Their help and contributions in maintaining the quality of the journal is greatly appreciated. Many authors, regardless of whether International Journal of Chemistry publishes their work, appreciate the helpful feedback provided by the reviewers.Reviewers for Volume 9, Number 2 Abdul Rouf Dar, University of Florida, USAAhmet Ozan Gezerman, Institute of Science, TurkeyAsghari Gul, Comsats IIT, PakistanAyodele Temidayo Odularu, University of Fort Hare, South AfricaBhargava Karumudi, University of Illinois at Chicago, USABinod P Pandey, The Pennsylvania State University, USADesheng Zheng, University of Houston, USAFatima Tuz Johra, Kookmin University, BangladeshGreg Peters, University of Findlay, USAJiajue Chai, Brown University, USAMaolin Lu, Yale University, USAMeriem Belhachemi, University of Bechar, AlgeriaMohamed Abass, Ain Shams University, EgyptMonira Nessem Michael, National institute of standards (NIS), EgyptMustafa Oguzhan Kaya, Siirt University, TurkeyNejib Hussein Mekni, Al Manar University, TunisiaPraveen Kumar, Texas Tech University, USAR. K. Dey, Birla Institute of Technology (BIT), IndiaSayandev Chatterjee, Pacific Northwest National Laboratory, USASitaram Acharya, Texas Christian University, USASujan Kumar Sarkar, Ruhr University Bochum, GermanyWaseem Hassan, Universidade Federal de Santa Maria, Brazil         Albert JohnOn behalf of,The Editorial Board of International Journal of ChemistryCanadian Center of Science and Education
Użyteczność modeli parametrycznych i sztucznych sieci neuronowych w prognozowaniu kosztów produkcji
Authors: Leszczyński Zbigniew , Jasiński Tomasz
Published: April 2017

Użyteczność modeli parametrycznych i sztucznych sieci neuronowych w prognozowaniu kosztów produkcji

The aim of the paper is to analyze parametric models and artificial neural networks in terms of their suitability as estimation tools of the production costs. Estimated production costs are a fundamental determinant of the decision-making process by costs engineers relating to design and management costs of new products, infrastructure projects and production lines. The first part of the paper presents a con- ceptual framework for the construction of a model of production costs parametric estimation, multidimensional with linear and nonlinear dependency. It then discusses the nature and use of artificial neural networks as nonparametric estimates of production costs. In both parts of the article, an empirical study is conducted with the use of adequate statistical methods and artificial neurons. This study presents proce- dures for construction of models of parametric and nonparametric estimation of production costs and discusses their advantages and disadvantages. It also presents the application and usefulness of both models for estimating production costs in production environment.
Modyfikacja zakresu analizy kosztów wydobycia węgla kamiennego z uwzględnieniem cyklu życia wyrobiska wybierkowego
Authors: Segeth-Boniecka Katarzyna
Published: April 2017

Modyfikacja zakresu analizy kosztów wydobycia węgla kamiennego z uwzględnieniem cyklu życia wyrobiska wybierkowego

The aim of the article is to present the results of research on validity and possibilities of using longwall life cycle in the analysis of hard coal extraction costs. Moreover, it aims to indicate the benefits accruing from its application in management of hard coal mines. The article addresses a topical and important issue of solu- tions in the cost analysis sphere in Polish hard coal mines, which has not been thoroughly researched yet. The cost analysis of the longwall life cycle would support the cost planning process by facilitating the estimation of extraction profitability. It would also aid the monitoring and the control of incurred costs on an ongoing basis and enable adoption of possible corrective measures. Finally, it would become a significant tool in the process of assessment if the goals are attained, as well as identifying variations and their causes. To achieve the aforementioned aims, a review of relevant literature was conducted. All the analyses were based on data collected during research conducted in years 2013–2014 in one of three largest coal compa- nies in Poland.
Konferencje naukowe w dziedzinie rachunkowości i finansów organizowane w 2017 roku przez szkoły wyższe w Polsce
Authors: Szychta Anna
Published: April 2017

Konferencje naukowe w dziedzinie rachunkowości i finansów organizowane w 2017 roku przez szkoły wyższe w Polsce
A map of abstract relational knowledge in the human hippocampal–entorhinal cortex
Authors: Garvert Mona M , Dolan Raymond J , Behrens Timothy EJ
Published: April 2017

The hippocampal–entorhinal system encodes a map of space that guides spatial navigation. Goal-directed behaviour outside of spatial navigation similarly requires a representation of abstract forms of relational knowledge. This information relies on the same neural system, but it is not known whether the organisational principles governing continuous maps may extend to the implicit encoding of discrete, non-spatial graphs. Here, we show that the human hippocampal–entorhinal system can represent relationships between objects using a metric that depends on associative strength. We reconstruct a map-like knowledge structure directly from a hippocampal–entorhinal functional magnetic resonance imaging adaptation signal in a situation where relationships are non-spatial rather than spatial, discrete rather than continuous, and unavailable to conscious awareness. Notably, the measure that best predicted a behavioural signature of implicit knowledge and blood oxygen level-dependent adaptation was a weighted sum of future states, akin to the successor representation that has been proposed to account for place and grid-cell firing patterns.
PPP1R15A-mediated dephosphorylation of eIF2α is unaffected by Sephin1 or Guanabenz
Authors: Crespillo-Casado Ana , Chambers Joseph E , Fischer Peter M , Marciniak Stefan J , Ron David
Published: April 2017

Dephosphorylation of translation initiation factor 2 (eIF2α) terminates signalling in the mammalian integrated stress response (ISR) and has emerged as a promising target for modifying the course of protein misfolding diseases. The [(o-chlorobenzylidene)amino]guanidines (Guanabenz and Sephin1) have been proposed to exert protective effects against misfolding by interfering with eIF2α-P dephosphorylation through selective disruption of a PP1-PPP1R15A holophosphatase complex. Surprisingly, they proved inert in vitro affecting neither stability of the PP1-PPP1R15A complex nor substrate-specific dephosphorylation. Furthermore, eIF2α-P dephosphorylation, assessed by a kinase shut-off experiment, progressed normally in Sephin1-treated cells. Consistent with its role in defending proteostasis, Sephin1 attenuated the IRE1 branch of the endoplasmic reticulum unfolded protein response. However, repression was noted in both wildtype and Ppp1r15a deleted cells and in cells rendered ISR-deficient by CRISPR editing of the Eif2s1 locus to encode a non-phosphorylatable eIF2α (eIF2αS51A). These findings challenge the view that [(o-chlorobenzylidene)amino]guanidines restore proteostasis by interfering with eIF2α-P dephosphorylation.
Membrane and luminal proteins reach the apicoplast by different trafficking pathways in the malaria parasitePlasmodium falciparum
Authors: Chaudhari Rahul , Dey Vishakha , Narayan Aishwarya , Sharma Shobhona , Patankar Swati
Published: April 2017

The secretory pathway inPlasmodium falciparumhas evolved to transport proteins to the host cell membrane and to an endosymbiotic organelle, the apicoplast. The latter can occur via the ER or the ER-Golgi route. Here, we study these three routes using proteins Erythrocyte Membrane Protein-1 (PfEMP1), Acyl Carrier Protein (ACP) and glutathione peroxidase-like thioredoxin peroxidase (PfTPxGl) and inhibitors of vesicular transport. As expected, the G protein-dependent vesicular fusion inhibitor AlF4−and microtubule destabilizing drug vinblastine block the trafficking of PfEMP-1, a protein secreted to the host cell membrane. However, while both PfTPxGland ACP are targeted to the apicoplast, only ACP trafficking remains unaffected by these treatments. This implies that G protein-dependent vesicles do not play a role in classical apicoplast protein targeting. Unlike the soluble protein ACP, we show that PfTPxGlis localized to the outermost membrane of the apicoplast. Thus, the parasite apicoplast acquires proteins via two different pathways: first, the vesicular trafficking pathway appears to handle not only secretory proteins, but an apicoplast membrane protein, PfTPxGl; second, trafficking of apicoplast luminal proteins appear to be independent of G protein-coupled vesicles.
Asymmetrical dispersal and putative isolation-by-distance of an intertidal blenniid across the Atlantic–Mediterranean divide
Authors: Castilho Rita , Cunha Regina L. , Faria Cláudia , Velasco Eva M. , Robalo Joana I.
Published: April 2017

Transition zones are of high evolutionary interest because unique patterns of spatial variation are often retained. Here, we investigated the phylogeography of the peacock blenny,Salaria pavo, a small marine intertidal fish that inhabits rocky habitats of the Mediterranean and the adjacent Atlantic Ocean. We screened 170 individuals using mitochondrial and nuclear sequence data from eight locations. Four models of genetic structure were tested: panmixia, isolation-by-distance, secondary contact and phylogeographic break. Results indicated clear asymmetric migration from the Mediterranean to the Atlantic but only marginally supported the isolation-by-distance model. Additionally, the species displays an imprint of demographic expansion compatible with the last glacial maximum. Although the existence of a refugium in the Mediterranean cannot be discarded, the ancestral lineage most likely originated in the Atlantic, where most of the genetic diversity occurs.
Using conventionalF-statistics to study unconventional sex-chromosome differentiation
Authors: Rodrigues Nicolas , Dufresnes Christophe
Published: April 2017

Species with undifferentiated sex chromosomes emerge as key organisms to understand the astonishing diversity of sex-determination systems. Whereas new genomic methods are widening opportunities to study these systems, the difficulty to separately characterize their X and Y homologous chromosomes poses limitations. Here we demonstrate that two simpleF-statistics calculated from sex-linked genotypes, namely the genetic distance (Fst) between sexes and the inbreeding coefficient (Fis) in the heterogametic sex, can be used as reliable proxies to compare sex-chromosome differentiation between populations. We correlated these metrics using published microsatellite data from two frog species (Hyla arboreaandRana temporaria), and show that they intimately relate to the overall amount of X–Y differentiation in populations. However, the fits for individual loci appear highly variable, suggesting that a dense genetic coverage will be needed for inferring fine-scale patterns of differentiation along sex-chromosomes. The applications of theseF-statistics, which implies little sampling requirement, significantly facilitate population analyses of sex-chromosomes.
Plant traits and environment: floating leaf blade production and turnover of waterlilies
Authors: Klok Peter F. , van der Velde Gerard
Published: April 2017

Floating leaf blades of waterlilies fulfill several functions in wetland ecosystems by production, decomposition and turnover as well as exchange processes. Production and turnover rates of floating leaf blades of three waterlily species, Nuphar lutea (L.) Sm., Nymphaea alba L. and Nymphaea candida Presl, were studied in three freshwater bodies, differing in trophic status, pH and alkalinity. Length and percentages of leaf loss of marked leaf blades were measured weekly during the growing season. Area and biomass were calculated based on leaf length and were used to calculate the turnover rate of floating leaf blades. Seasonal changes in floating leaf production showed that values decreased in the order: Nymphaea alba, Nuphar lutea, Nymphaea candida. The highest production was reached for Nuphar lutea and Nymphaea alba in alkaline, eutrophic water bodies. The production per leaf was relatively high for both species in the acid water body. Nymphaea candida showed a very short vegetation period and low turnover rates. The ratio Total potential leaf biomass/Maximum potential leaf biomass (P/Bmax) of the three species ranged from 1.35–2.25. The ratio Vegetation period (Period with floating leaves)/Mean leaf life span ranged from 2.94–4.63, the ratio Growth period (Period with appearance of new floating leaves)/Vegetation period from 0.53–0.73. The clear differences between Nymphaea candida versus Nuphar lutea and Nymphaea alba, may be due to adaptations of Nymphaea candida to an Euro-Siberic climate with short-lasting summer conditions.
Relic populations ofFukomysmole-rats in Tanzania: description of two new speciesF. livingstonisp. nov. andF. hanangensissp. nov.
Authors: Faulkes Chris G. , Mgode Georgies F. , Archer Elizabeth K. , Bennett Nigel C.
Published: April 2017

Previous studies of African mole-rats of the generaHeliophobiusandFukomys(Bathyergidae) in the regions of East and south central Africa have revealed a diversity of species and vicariant populations, with patterns of distribution having been influenced by the geological process of rifting and changing patterns of drainage of major river systems. This has resulted in most of the extant members of the genusFukomysbeing distributed west of the main Rift Valley. However, a small number of isolated populations are known to occur east of the African Rift Valley in Tanzania, whereHeliophobiusis the most common bathyergid rodent. We conducted morphological, craniometric and phylogenetic analysis of mitochondrial cytochrome b (cyt b) sequences of two allopatric populations of Tanzanian mole-rats (genusFukomys) at Ujiji and around Mount Hanang, in comparison with both geographically adjacent and more distant populations ofFukomys. Our results reveal two distinct evolutionary lineages, forming clades that constitute previously unnamed species. Here, we formally describe and designate these new speciesF. livingstoniandF. hanangensisrespectively. Molecular clock-based estimates of divergence times, together with maximum likelihood inference of biogeographic range evolution, offers strong support for the hypothesis that vicariance in the Western Rift Valley and the drainage patterns of major river systems has subdivided populations of mole-rats. More recent climatic changes and tectonic activity in the “Mbeya triple junction” and Rungwe volcanic province between Lakes Rukwa and Nyasa have played a role in further isolation of these extra-limital populations ofFukomysin Tanzania.
The impacts of drift and selection on genomic evolution in insects
Authors: Tong K. Jun , Duchêne Sebastián , Lo Nathan , Ho Simon Y.W.
Published: April 2017

Genomes evolve through a combination of mutation, drift, and selection, all of which act heterogeneously across genes and lineages. This leads to differences in branch-length patterns among gene trees. Genes that yield trees with the same branch-length patterns can be grouped together into clusters. Here, we propose a novel phylogenetic approach to explain the factors that influence the number and distribution of these gene-tree clusters. We apply our method to a genomic dataset from insects, an ancient and diverse group of organisms. We find some evidence that when drift is the dominant evolutionary process, each cluster tends to contain a large number of fast-evolving genes. In contrast, strong negative selection leads to many distinct clusters, each of which contains only a few slow-evolving genes. Our work, although preliminary in nature, illustrates the use of phylogenetic methods to shed light on the factors driving rate variation in genomic evolution.
On the entry of an emerging arbovirus into host cells: Mayaro virus takes the highway to the cytoplasm through fusion with early endosomes and caveolae-derived vesicles
Authors: Carvalho Carlos A.M. , Silva Jerson L. , Oliveira Andréa C. , Gomes Andre M.O.
Published: April 2017

Mayaro virus (MAYV) is an emergent sylvatic alphavirus in South America, related to sporadic outbreaks of a chikungunya-like human febrile illness accompanied by severe arthralgia. Despite its high potential for urban emergence, MAYV is still an obscure virus with scarce information about its infection cycle, including the corresponding early events. Even for prototypical alphaviruses, the cell entry mechanism still has some rough edges to trim: although clathrin-mediated endocytosis is quoted as the putative route, alternative paths as distinct as direct virus genome injection through the cell plasma membrane seems to be possible. Our aim was to clarify crucial details on the entry route exploited by MAYV to gain access into the host cell. Tracking the virus since its first contact with the surface of Vero cells by fluorescence microscopy, we show that its entry occurs by a fast endocytic process and relies on fusion with acidic endosomal compartments. Moreover, blocking clathrin-mediated endocytosis or depleting cholesterol from the cell membrane leads to a strong inhibition of viral infection, as assessed by plaque assays. Following this clue, we found that early endosomes and caveolae-derived vesicles are both implicated as target membranes for MAYV fusion. Our findings unravel the very first events that culminate in a productive infection by MAYV and shed light on potential targets for a rational antiviral therapy, besides providing a better comprehension of the entry routes exploited by alphaviruses to get into the cell.
The genetics of venom ontogeny in the eastern diamondback rattlesnake (Crotalus adamanteus)
Authors: Rokyta Darin R. , Margres Mark J. , Ward Micaiah J. , Sanchez Elda E.
Published: April 2017

The same selective forces that give rise to rapid inter- and intraspecific divergence in snake venoms can also favor differences in venoms across life-history stages. Ontogenetic changes in venom composition are well known and widespread in snakes but have not been investigated to the level of unambiguously identifying the specific loci involved. The eastern diamondback rattlesnake was previously shown to undergo an ontogenetic shift in venom composition at sexual maturity, and this shift accounted for more venom variation than geography. To characterize the genetics underlying the ontogenetic venom compositional change in C. adamanteus, we sequenced adult/juvenile pairs of venom-gland transcriptomes from five populations previously shown to have different adult venom compositions. We identified a total of 59 putative toxin transcripts for C. adamanteus, and 12 of these were involved in the ontogenetic change. Three toxins were downregulated, and nine were upregulated in adults relative to juveniles. Adults and juveniles expressed similar total levels of snake-venom metalloproteinases but differed substantially in their featured paralogs, and adults expressed higher levels of Bradykinin-potentiating and C-type natriuretic peptides, nerve growth factor, and specific paralogs of phospholipases A2 and snake venom serine proteinases. Juvenile venom was more toxic to mice, indicating that the expression differences resulted in a phenotypically, and therefore potentially ecologically, significant difference in venom function. We also showed that adult and juvenile venom-gland transcriptomes for a species with known ontogenetic venom variation were equally effective at individually providing a full characterization of the venom genes of a species but that any particular individual was likely to lack several toxins in their transcriptome. A full characterization of a species’ venom-gene complement therefore requires sequencing more than one individual, although the ages of the individuals are unimportant.
Seismic anisotropy of Precambrian lithosphere: Insights from Rayleigh wave tomography of the eastern Superior Craton
Authors: Petrescu Laura , Darbyshire Fiona , Bastow Ian , Totten Eoghan , Gilligan Amy
Published: April 2017

The thick, seismically fast lithospheric keels underlying continental cores (cratons) are thought to have formed in the Precambrian and resisted subsequent tectonic destruction. A consensus is emerging from a variety of disciplines that keels are vertically stratified, but the processes that led to their development remain uncertain. Eastern Canada is a natural laboratory to study Precambrian lithospheric formation and evolution. It comprises the largest Archean craton in the world, the Superior Craton, surrounded by multiple Proterozoic orogenic belts. To investigate its lithospheric structure, we construct a frequency‐dependent anisotropic seismic model of the region using Rayleigh waves from teleseismic earthquakes recorded at broadband seismic stations across eastern Canada. The joint interpretation of phase velocity heterogeneity and azimuthal anisotropy patterns reveals a seismically fast and anisotropically complex Superior Craton. The upper lithosphere records fossilized Archean tectonic deformation: anisotropic patterns align with the orientation of the main tectonic boundaries at periods ≤110 s. This implies that cratonic blocks were strong enough to sustain plate‐scale deformation during collision at 2.5 Ga. Cratonic lithosphere with fossil anisotropy partially extends beneath adjacent Proterozoic belts. At periods sensitive to the lower lithosphere, we detect fast, more homogenous, and weakly anisotropic material, documenting postassembly lithospheric growth, possibly in a slow or stagnant convection regime. A heterogeneous, anisotropic transitional zone may also be present at the base of the keel. The detection of multiple lithospheric fabrics at different periods with distinct tectonic origins supports growing evidence that cratonization processes may be episodic and are not exclusively an Archean phenomenon.
Altered inherent optical properties and estimates of the underwater light field during an Arctic under‐ice bloom of Phaeocystis pouchetii
Authors: Pavlov Alexey K. , Taskjelle Torbjørn , Kauko Hanna M. , Hamre Børge , Hudson Stephen R. , Assmy Philipp , Duarte Pedro , Fernández‐Méndez Mar , Mundy C. J. , Granskog Mats A.
Published: April 2017

In spring 2015, we observed an extensive phytoplankton bloom of Phaeocystis pouchetii, with chlorophyll a concentrations up to 7.5 mg m−3, under compact snow‐covered Arctic sea ice at 80–81°N during the Norwegian young sea ICE (N‐ICE2015) expedition. We investigated the influence of the under‐ice bloom on inherent optical properties (IOPs) of the upper ocean. Absorption and scattering in the upper 20 m of the water column at visible wavebands increased threefold and tenfold, respectively, relative to prebloom conditions. The scattering‐to‐absorption ratio during the Phaeocystis under‐ice bloom was higher than in previous Arctic studies investigating diatom blooms. During the bloom, absorption by colored dissolved organic matter (at 375 nm), seemingly of autochthonous origin, doubled. Total absorption by particles (at 440 nm), dominated by phytoplankton (>90%), increased tenfold. Measured absorption and scattering in the water were used as inputs for a 1D coupled atmosphere‐ice‐ocean radiative transfer model (AccuRT) to investigate effects of altered IOPs on the under‐ice light field. Multiple scattering between sea ice and phytoplankton in the ocean led to an increase in scalar irradiance in the photosynthetically active radiation range (Eo(PAR)) at the ice‐ocean interface by 6–7% compared to prebloom situation. This increase could have a positive feedback on ice‐algal and under‐ice phytoplankton productivity. The ratio between Eo(PAR) and downwelling planar irradiance (Ed(PAR)) below sea ice reached 1.85. Therefore, the use of Ed(PAR) might significantly underestimate the amount of PAR available for photosynthesis underneath sea ice. Our findings could help to improve light parameterizations in primary production models.
3‐D seismic tomography of the lithosphere and its geodynamic implications beneath the northeast India region
Authors: Raoof J. , Mukhopadhyay S. , Koulakov I. , Kayal J. R.
Published: April 2017

We have evolved 3‐D seismic velocity structures in northeast India region and its adjoining areas to understand the geodynamic processes of Indian lithosphere that gently underthrusts under the Himalayas and steeply subducts below the Indo‐Burma Ranges. The region is tectonically buttressed between the Himalayan arc to the north and the Indo‐Burmese arc to the east. The tomographic image shows heterogeneous structure of lithosphere depicting different tectonic blocks. Though our results are limited to shallower depth (0–90 km), it matches well with the deeper continuation of lithospheric structure obtained in an earlier study. We observe low‐velocity structure all along the Eastern Himalayas down to ~70 km depth, which may be attributed to deeper roots/thicker crust developed by underthrusting of Indian plate. Parallel to this low‐velocity zone lies a high‐velocity zone in foredeep region, represents the Indian lithosphere. The underthrusting Indian lithosphere under the Himalayas as well as below the Indo‐Burma Ranges is well reflected as a high‐velocity dipping structure. The buckled up part of bending Indian plate in study region, the Shillong Plateau‐Mikir Hills tectonic block, is marked as a high‐velocity structure at shallower depth. The Eastern Himalayan Syntaxis, tectonic block where the two arcs meet, is identified as a high‐velocity structure. The Bengal Basin, tectonic block to the south of Shillong Plateau, shows low velocity due to its thicker sediments. Based on the tomographic image, a schematic model is presented to elucidate the structure and geodynamics of Indian lithosphere in study region.