bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimal perturbation for two-dimensional vortex systems: route to non-axisymmetric state
Authors: Navrose  , Johnson H. G. , Brion V. , Jacquin L. , Robinet J. C.
Published: September 2018

We investigate perturbations that maximize the gain of disturbance energy in a two-dimensional isolated vortex and a counter-rotating vortex pair. The optimization is carried out using the method of Lagrange multipliers. For low initial energy of the perturbation (
$E(0)$
), the nonlinear optimal perturbation/gain is found to be the same as the linear optimal perturbation/gain. Beyond a certain threshold
$E(0)$
, the optimal perturbation/gain obtained from linear and nonlinear computations are different. There exists a range of
$E(0)$
for which the nonlinear optimal gain is higher than the linear optimal gain. For an isolated vortex, the higher value of nonlinear optimal gain is attributed to interaction among different azimuthal components, which is otherwise absent in a linearized system. Spiral dislocations are found in the nonlinear optimal perturbation at the radial location where the most dominant wavenumber changes. Long-time nonlinear evolution of linear and nonlinear optimal perturbations is studied. The evolution shows that, after the initial increment of perturbation energy, the vortex attains a quasi-steady state where the mean perturbation energy decreases on a slow time scale. The quasi-steady vortex state is non-axisymmetric and its shape depends on the initial perturbation. It is observed that the lifetime of a quasi-steady vortex state obtained using the nonlinear optimal perturbation is longer than that obtained using the linear optimal perturbation. For a counter-rotating vortex pair, the mechanism that maximizes the energy gain is found to be similar to that of the isolated vortex. Within the linear framework, the optimal perturbation for a vortex pair can be either symmetric or antisymmetric, whereas the structure of the nonlinear optimal perturbation, beyond the threshold
$E(0)$
, is always asymmetric. No quasi-steady state for a counter-rotating vortex pair is observed.
Nothing about us, without us: A case study of a consumer-run organization by and for people on the autism spectrum in the Netherlands
Authors: van den Bosch Karin E. , Krzeminska Anna , Song Eun Young , van Hal Lineke B. E. , Waltz Mitzi M. , Ebben Hannah , Schippers Alice P.
Published: September 2018

In this exploratory case study based on qualitative research, we explore the perspectives and experiences of autistic self-advocates in the Netherlands regarding autism, (self-)advocacy, and consumer-run organizations. The focus of our study is a consumer-run organization by and for adult Persons on the Autism Spectrum in the Netherlands: PAS-Nederland or PAS for short. Our analysis reveals four themes relevant to the acceptance and integration of adults with autism into society and work: (1) invisibility of autistic adults; (2) diversity of the autism spectrum; (3) autistic leadership; and (4) collaboration between people with and without autism. We discuss the practical implications of our findings for the inclusion of people with autism in work and society. Our study underscores the importance of putting autistic people at the center of decision-making processes and solutions aimed at improving their outcomes in society, in general, and in the workplace specifically.
Active seismic studies in valley glacier settings: strategies and limitations
Authors: ZECHMANN JENNA M. , BOOTH ADAM D. , TRUFFER MARTIN , GUSMEROLI ALESSIO , AMUNDSON JASON M. , LARSEN CHRISTOPHER F.
Published: September 2018

Subglacial tills play an important role in glacier dynamics but are difficult to characterize in situ. Amplitude Variation with Angle (AVA) analysis of seismic reflection data can distinguish between stiff tills and deformable tills. However, AVA analysis in mountain glacier environments can be problematic: reflections can be obscured by Rayleigh wave energy scattered from crevasses, and complex basal topography can impede the location of reflection points in 2-D acquisitions. We use a forward model to produce challenging synthetic seismic records in order to test the efficacy of AVA in crevassed and geometrically complex environments. We find that we can distinguish subglacial till types in moderately crevassed environments, where ‘moderate’ depends on crevasse spacing and orientation. The forward model serves as a planning tool, as it can predict AVA success or failure based on characteristics of the study glacier. Applying lessons from the forward model, we perform AVA on a seismic dataset collected from Taku Glacier in Southeast Alaska in March 2016. Taku Glacier is a valley glacier thought to overlay thick sediment deposits. A near-offset polarity reversal confirms that the tills are deformable.
Phylogenetic relationships of the family Gryporhynchidae (Cestoda: Cyclophyllidea) inferred through SSU and LSU rDNA sequences
Authors: Ortega-Olivares M.P. , García-Varela M.
Published: September 2018

Tapeworms of the family Gryporhynchidae are endoparasites of fish-eating birds distributed worldwide. Currently the family contains 16 genera classified on the basis of the morphology of the rostellar apparatus, rostellar hooks and strobilar anatomy. However, the phylogenetic relationships among the genera are still unknown. In this study, sequences of the near complete 18S (SSU) and 28S (LSU) from rDNA of 13 species of gryporhynchids (adult specimens) representing eight genera (Cyclustera,Dendrouterina,Glossocercus, Gryporhynchidae gen. sp.,Neovalipora,Paradilepis,Parvitaenia,Valipora) and one species of metacestode from fish (Neovalipora) were generated. Additionally, sequences of metacestodes of the generaAmirthalingamia,Neogryporhynchus,Paradilepis,ParvitaeniaandValiporafrom Africa recently added to the GenBank database were analysed. Phylogenetic relationships were inferred using maximum-likelihood (ML) and Bayesian inference of each (SSU and LSU) dataset. The phylogenetic analyses indicated that the family Gryporhynchidae is a well-supported monophyletic group within the Cyclophyllidea. The trees inferred with SSU and LSU datasets had similar topologies and suggested that the generaGlossocercus(two species sequenced) andParadilepis(four spp.) are monophyletic. In contrast,Dendrouterina,ParvitaeniaandValiporaare paraphyletic, suggesting that the species composition of these genera should be critically reviewed. Interestingly, species of the genera that use the same groups of definitive hosts such as herons (Ardeidae), cormorants (Phalacrocoracidae) and ibis (Threskiornithidae) are together in the phylogenetic tree, even though they differ markedly from each other in some morphological characters, especially shape and size of rostellar hooks.
LA NAZIONALIZZAZIONE DEL VOTO
Authors: Caramani Daniele
Published: September 2018

Introduzione

Talvolta, teorie suggestive e portatrici di importanti potenzialità euristiche non trovano sempre quella collocazione teorica ed empirica che ne farebbe fonte di nuove conoscenze e di freschi impulsi analitici. Accade inoltre che riflessione concettuale e misure formali semplici ma ricche in sostanza e contenuti vengano trascurate a vantaggio di sofisticate metodologie e tecniche sproporzionate rispetto ai fini teorici conseguiti. Infine, la disciplina della scienza politica è caratterizzata da fenomeni di moda, che dirigono sia la produzione teorica che la ricerca empirica verso certi campi a discapito di altri.
LA NUOVA LEGGE ELETTORALE IN PARLAMENTO: CHI, COME E PERCHÉ
Authors: Pappalardo Adriano
Published: September 2018

Introduzione

Il 6 agosto 1993 apparivano sulla Gazzetta ufficiale le leggi n. 276 e 277, contenenti la nuova normativa elettorale per il Senato e la Camera dei deputati. Si concludeva così l'iterdi una riforma cruciale e, in conformità a una consolidata tradizione, il traguardo veniva tagliato all'ultimo momento e sotto la pressione di scadenze inderogabili e drammatici sviluppi politici. Proprio il 6 agosto, infatti, l'intera materia avrebbe potuto tornare in alto mare per effetto dei poteri referenti conferiti dalla legge alla Commissione bicamerale che aveva avviato la riforma nel settembre 1992. Ma, a prescindere dalle prescrizioni costituzionali, sia i tempi che i contenuti del processo decisionale appaiono scanditi (se non puntualmente spiegati) da circostanze contestuali (referendum), sulle quali si innestano strategie invariabilmente reattive dei partiti.
PARTITI DI CENTRO E PARTITI CENTRALI: UNA CHIARIFICAZIONE CONCETTUALE
Authors: Hazan Reuven Y.
Published: September 2018

Introduzione

Molti partiti riformisti nella storia di Francia ed Inghilterra, i vecchi partiti agrari nella Scandinavia del dopoguerra ed alcuni nuovi partiti delle riemergenti democrazie, sia nell'Europa meridionale che in quella orientale, si sono etichettati come partiti «di centro». Ma si tratta di veri partiti di centro? E se questo è vero, a che tipo di partito di centro appartengono?
UNA VIGILIA DI INCERTEZZE
Authors: Sani Giacomo
Published: September 2018

Introduzione

In tutte le democrazie i mesi che precedono una scadenza elettorale sono caratterizzati da un certo grado di incertezza che, a seconda delle particolarità del sistema politico, può riguardare il nome del vincitore, il margine della vittoria (o della sconfitta) di questo o di quel gruppo politico, il raggiungimento da parte di un cartello elettorale della maggioranza dei seggi nelle assemblee legislative, o le conseguenze del verdetto per lepoliciesdel futuro governo. A posteriori l'esito di una consultazione qualche volta appare scontato; ma basta ricollocarsi nell'atmosfera delle settimane e dei mesi che precedono il voto per rendersi conto del clima disuspense, dei timori e delle speranze con i quali protagonisti, osservatori e cittadini vivono la vigilia.
MEDIA, SONDAGGI E SPESE ELETTORALI: LA NUOVA DISCIPLINA
Authors: Fusaro Carlo
Published: September 2018

Introduzione

La legge 10 dicembre 1993, n. 515 costituisce un vero e proprio «sistema elettorale di contorno». Pur constando di soli 20 articoli, si tratta di un testo di notevole complessità e assai eterogeneo. Questo saggio si propone di illustrarne genesi e contenuti, di mettere in luce alcune delle problematiche che ha sollevato e di esprimere qualche valutazione sulla sua prima applicazione in occasione delle elezioni del 1994.
DAI PARTITI Al POLI. LA POLITICA DELLE ALLEANZE
Authors: Virgilio Aldo Di
Published: September 2018

Introduzione

Le elezioni politiche del 27-28 marzo 1994 si sono svolte in un quadro competitivo contrassegnato, rispetto al passato recente, da molteplici novità. Tali novità debbono attribuirsi essenzialmente alla concomitanza e all'intreccio di due fattori, fonte entrambi di incertezza e di (potenziale) trasformazione: (a) il cambiamento della legge elettorale e (b) il prodursi (nell'ultimo biennio) di un rapido quanto imprevisto processo di destrutturazione partitica. Come conseguenza della ridefinizione della struttura dei vincoli e degli incentivi competitivi degli attori (nuova legge elettorale) e/o per effetto del mutamento partitico e della transizione verso equilibri partitici non ben definiti ma sicuramente diversi da quelli tradizionali (processo di destrutturazione), ne è scaturita un'offerta elettorale dalla configurazione per buona parte inedita.
ELOGIO DEL SEMI-PRESIDENZIALISMO
Authors: Sartori Giovanni
Published: September 2018

Il prototipo francese

Si è già veduto (Sartori 1994, capp. 5 e 6) che tanto il presidenzialismo quanto il parlamentarismo, soprattutto nella loro forma pura, lasciano molto da desiderare. Questi due estremi ci inducono a ricercare una soluzione «mista», una forma politica a mezza strada fra sistemi presidenziali e sistemi parlamentari, ricavata da entrambi. Tale forma mista è nota come semi-presidenzialismo. L'etichetta non va presa troppo alla lettera; ma suggerisce che il sistema misto in questione può essere compreso meglio facendo capo al presidenzialismo anziché partendo dal parlamentarismo, argomentando dall'alto in basso anziché dalla base parlamentare verso l'alto.
LA POLITICIZZAZIONE DI UN POTERE NEUTRALE. MAGISTRATURA E CRISI ITALIANA
Authors: Righettini Stella
Published: September 2018

Introduzione

Le vicende ditangentopolie le relative conseguenze politico-istituzionali hanno conferito all'intervento giudiziario un rilievo maggiore che in passato rispetto ai complessi rapporti tra poteri dello Stato e tra governanti e governati. La magistratura, soprattutto quella penale, mostra di aver acquisito una consapevolezza del proprio ruolo e delle proprie funzioni nell'ambito del sistema politico come forse mai in precedenza nella storia della repubblica. Ci si interroga ancora oggi, a tre anni di distanza dall'inizio ditangentopoli, sul perché l'intervento dei magistrati abbia accelerato la crisi del regime democratico italiano e favorito l'inizio di una fase di transizione. Ci si chiede, inoltre, in che misura, con quali conseguenze e per quanto tempo ancora gli attori giudiziari saranno in grado di conservare un potenziale di influenza così ampio sul sistema politico e sulla funzionalità di istituzioni governative e parlamentari.
LE ALLEANZE ELETTORALI. IDENTITÀ PARTITICHE E LOGICHE COALIZIONALI
Authors: Di Virgilio Aldo
Published: September 2018

La politica delle alleanze nella transizione italiana

L'emergere di una competizione tra coalizioni partitiche rappresenta una delle principali conseguenze delle regole per l'elezione dei due rami del parlamento, dei consigli regionali e degli organismi amministrativi di comuni e province adottate in Italia fra il 1993 e il 19951. Nell'operatività dei nuovi sistemi elettorali, la scelta dell'aggregazione fa capo agli aspetti maggioritari del meccanismo di voto (l'elezione dei deputati e dei senatori nei collegi uninominali, l'attribuzione del premio di maggioranza nei consigli regionali, l'elezione del sindaco e del presidente della provincia), ancorati, con maggiore o minore forza cogente, allo scopo di «votare per eleggere un governo»2. In tal modo, la politica delle alleanze si è affermata come un elemento permanente del processo elettorale, decisivo ai fini del risultato e non privo di implicazioni sull'evoluzione strutturale del sistema partitico. La formazione delle coalizioni e la progressiva ridefinizione dell'offerta coalizionale, in effetti, hanno cadenzato fin qui i passaggi elettorali della transizione italiana. La forza aggregativa del Pds e la sua capacità di attivare una logica di schieramento si rivelarono determinanti, in assenza di coalizioni alternative, per il successo della sinistra negli importanti test elettorali locali dell'estate e dell'autunno 1993. La formula inventata da Silvio Berlusconi per colmare il deficit di offerta sul fronte moderato – il cartello elettorale a geografia variabile che vedeva la sua nuova formazione politica alleata al Nord con la Lega e al Sud con il Msi-An – consentì alle destre di vincere le elezioni politiche del marzo 1994. Nella fase successiva, il vincolo delle alleanze ha determinato la rottura del polo di centro e il riequilibrio coalizionale che ne è scaturito ha favorito, alle elezioni regionali dell'aprile 19953, il dispiegarsi di una competizione tendenzialmente bipolare tra due schieramenti di analoga forza.
LE AUTORITÀ INDIPENDENTI IN ITALIA COME TEMA DI RICERCA
Authors: Morisi Massimo
Published: September 2018

Introduzione

Le funzioni di cui si occupano le autorità indipendenti nel nostro paese, formano un elenco abbastanza impressionante. A tali istituzioni viene infatti affidata una complessa gamma di funzioni decisionali in una molteplicità di settori di regolazione economica e sociale di cruciale importanza. Moneta e credito, concorrenza e assicurazioni, borsa, valori mobiliari e fondi pensione, comunicazioni di massa e informatica pubblica, appalti di lavori pubblici e tariffe di energia elettrica e gas, scioperi nei servizi pubblici e contrattazione sindacale nelle pubbliche amministrazioni, monitoraggio e innovazione neirambiente e nel funzionamento del sistema sanitario sono solo i più evidenti items di un profondo spostamento di poteri dall'apparato politico e amministrativo di governo verso una rete articolata, e in continua diramazione, di nuove e separate arene di rappresentazione, intermediazione o aggiudicazione, secondo i casi, di interessi. Chi domani volesse impegnarsi in ricerche empiriche sulle politiche pubbliche in questi settori decisivi per il sistema economico e sociale di questo paese, dovrebbe primariamente sottoporre ad analisi l'azione delle authorities e le reti di relazioni con gli interessi organizzati e diffusi in cui esse sono chiamate ad operare. Il campo visivo della rilevazione andrebbe profondamente riorientato. Solo ex post andrebbe ponderato il ruolo delle istituzioni classiche della forma di governo, come i partiti, gli organi dell'Esecutivo e il Parlamento. L'analisi empirica, a fronte di casi e circostanze determinate, potrebbe anche sancirne la (de) qualificazione alla sola stregua di attori e arene integrative.
LE POLITICHE DELLA SCUOLA IN EUROPA. UN'ANALISI COMPARATA
Authors: Ventura Sofia
Published: September 2018

Introduzione

Le politiche dell'istruzione costituiscono un ambito di studio rispetto al quale la scienza politica, nonché la più specifica disciplina dell'analisi delle politiche pubbliche, presentano notevoli lacune.

Da un lato, nella letteratura internazionale le numerose ricerche dieducation policysi sono concentrate prevalentemente su studi del caso singolo e hanno dedicato minore attenzione all'analisi comparata delle politiche scolastiche. Le quali, inoltre, sono state assai poco esplorate nell'ambito dei più generali studi comparati dedicati alwelfare state, che hanno piuttosto privilegiato lo studio delle politiche relative ai sistemi di assicurazione sociale; come ha rilevato Alber: «la sola ricerca empiricamente consolidata» in tale settore (Alber 1987, 15).

Dall'altro, nella letteratura politologica italiana la politica scolastica costituisce un terreno pressoché inesplorato. In Italia essa è stata, infatti, dominio dei pedagogisti, che hanno privilegiato approcci di tipo normativo, dei filosofi e, in misura minore, degli storici, il prevalente taglio descrittivo dei quali non ha, però, favorito lo sviluppo di analisi di tipo esplicativo (Benadusi 1989a, 258; Trivellato 1989, 226).
SUL CONCETTO DI «IMPRENDITORE DI POLICY»
Authors: Giuliani Marco
Published: September 2018

Introduzione

La diffusione di alcuni concetti nelle scienze sociali segue a volte percorsi imperscrutabili. Anche quando la sua origine non si perde in tempi lontani al punto da rendere necessaria una complessa ricostruzione etimologica, o quando il suo impiego non appare così strettamente improntato ad un contesto linguistico specifico, ripercorrere passo dopo passo la propagazione di un dato termine e il suo lento permeare il discorso scientifico può costituire un interessante percorso di ricerca.
The role of online dictionary advertisements in language reception, production, and retention
Authors: Dziemianko Anna
Published: September 2018

Today, people want to consult dictionaries of good quality, but they expect them to be available online for free. For this reason, publishers need advertisements to cover the costs of producing and maintaining online dictionary content. This paper aims to investigate the role of advertisements in language reception, production, and learning following online dictionary consultation. It also undertakes to determine whether advertisements in an online dictionary affect the time needed for dictionary-based decoding and encoding. In the experiment, participants consulted one of the most prestigious dictionaries of English for foreign learners, OALD9 (Oxford Advanced Learner’s Dictionary, 9th edition). Two versions of the dictionary were employed in the study: one that includes advertisements and is available online free of charge, and its advertisement-free counterpart, OALD9 Premium. In the receptive task, the participants were requested to explain the meaning of new English words. In the productive one, they had to use the words in sentences. Meaning retention was checked in the immediate post-test. The research reveals that advertisements in OALD9 impede language reception, production, and learning, and also extend the time for comprehending new words. Suggestions for further research into advertisements on dictionary websites are presented in the final part of the paper.
New Image Texture Analysis, and Application to Polymer Membrane Surface Morphologies and Roughness
Authors: Todd Clifford S. , Heeschen William A.
Published: September 2018

A new method of image texture analysis is presented, based on the mean and standard deviation of gray levels within domains in an image. The calculations are performed recursively on domains of various sizes within the images. These gray level calculations are used as the input matrix for principal component analysis. The technique analyzes the entire image as a whole and is not for image segmentation. The analysis routine operates across all distances, frequencies and directions in the image, and is not computationally burdensome. The method was applied to scanning electron microscope images of reverse osmosis membranes on domains from 23 nm to 3 µm. The texture analysis technique performed well in identifying the surface morphology and, once calibrated, in predicting the surface roughness as measured by atomic force microscopy.
Religion and Education in the Shadow of the European Court of Human Rights
Authors: Fokas Effie
Published: September 2018

This article presents a symposium on the “indirect effects” of the European Court of Human Rights jurisprudence on the place of religion in the educational sphere. The symposium showcases empirical research providing critical insight into how the Court's decisions may influence related domestic debates, raise public consciousness, and change how social actors perceive their rights and articulate their right claims in the area of religion and education. The research underpinning this symposium represents a clear departure from existing scholarship in this domain: it examines the impact of the Court not from the top-down (Court impact on states and their legislative frameworks) but from grassroots level upwards, in seeking to understand whether, how and to what extent Court decisions influence grassroots level actors' conceptions of their rights in the domain of religion and education and their efforts to secure new rights vis-à-vis their states.
Confirmation and Characterization of Non–target site Resistance to Fomesafen in Palmer amaranth (Amaranthus palmeri)
Authors: Varanasi Vijay K. , Brabham Chad , Norsworthy Jason K.
Published: September 2018

Palmer amaranth (Amaranthus palmeri S. Watson), a dioecious summer annual species, is one of the most troublesome weeds in U.S. cropping systems. The evolution of resistance to protoporphyrinogen oxidase inhibitors in A. palmeri biotypes is a major cause of concern to soybean [Glycine max (L.) Merr.] and cotton (Gossypium hirsutum L.) growers in the midsouthern United States. The objective of this study was to confirm and characterize the non–target site mechanism in a fomesafen-resistant accession from Randolph County, AR (RCA). A dose–response assay was conducted to assess the level of fomesafen resistance, and based on the GR50 values, the RCA accession was 18-fold more resistant to fomesafen than a susceptible (S) biotype. A TaqMan allelic discrimination assay and sequencing of the target-site genes PPX2 and PPX1 revealed no known or novel target-site mutations. An SYBR Green assay indicated no difference in PPX2 gene expression between the RCA and S biotypes. To test whether fomesafen resistance is metabolic in nature, the RCA and the S biotypes were treated with different cytochrome P450 (amitrole, piperonyl butoxide [PBO], malathion) and glutathione S-transferase (GST) (4-chloro-7-nitrobenzofurazan [NBD-Cl]) inhibitors, either alone or in combination with fomesafen. Malathion followed by (fb) fomesafen in RCA showed the greatest reduction in survival (67%) and biomass (86%) compared with fomesafen alone (45% and 66%, respectively) at 2 wk after treatment. Interestingly, NBD-Cl fb fomesafen also resulted in low survival (35%) compared with the fomesafen-only treatment (55%). Applications of malathion or NBD-Cl preceding fomesafen treatment resulted in reversal of fomesafen resistance, indicating the existence of cytochrome P450– and GST-based non–target site mechanisms in the RCA accession. This study confirms the first case of non–target site resistance to fomesafen in A. palmeri.
Using the Theory of Planned Behavior to Predict Faking in Selection	Exercises Varying in Fidelity
Authors: Dürr Daniel , Klehe Ute-Christine
Published: September 2018

Abstract. Faking has been a concern in selection research for many years. Many studies have examined faking in questionnaires while far less is known about faking in selection exercises with higher fidelity. This study applies the theory of planned behavior (TPB; Ajzen, 1991 ) to low- (interviews) and high-fidelity (role play, group discussion) exercises, testing whether the TPB predicts reported faking behavior. Data from a mock selection procedure suggests that candidates do report to fake in low- and high-fidelity exercises. Additionally, the TPB showed good predictive validity for faking in a low-fidelity exercise, yet not for faking in high-fidelity exercises.
The Importance of Combined Tidal and Meteorological Forces for the Flow and Sediment Transport on Intertidal Shoals
Authors: de Vet P. L. M. , van Prooijen B. C. , Schrijvershof R. A. , van der Werf J. J. , Ysebaert T. , Schrijver M. C. , Wang Z. B.
Published: September 2018

Estuarine intertidal areas are shaped by combined astronomical and meteorological forces. This paper reveals the relative importance of tide, surge, wind, and waves for the flow and sediment transport on large intertidal shoals. Results of an intensive field campaign have been used to validate a numerical model of the Roggenplaat intertidal shoal in the Eastern Scheldt Estuary, the Netherlands, in order to identify and quantify the importance of each of the processes over time and space. We show that its main tidal creeks are not the cause for the dominant direction of the net flow on the shoal. The tidal flow over the shoal is steered by the water level differences between the surrounding channels. Also during wind events, the tidal flow (enhanced by surge) is dominant in the creeks. In contrast, wind speeds of order 40 times the typical tidal flow velocity are sufficient to completely alter the flow direction and magnitude on an intertidal shoal. This has significant consequences for the sediment transport patterns. Apart from this wind‐driven flow dominance during these events, the wind also increases the bed shear stress by waves. For the largest intertidal part of the Roggenplaat, only ∼1–10% of the yearly transport results from the 50% least windy tides, even if the shoal is artificially lowered half the tidal range. This dominance of energetic meteorological conditions in the transports matches with field observations, in which the migration of the creeks and high parts of the shoal are in line with the predominant wind direction.
Bcl-xl as the most promising Bcl-2 family member in targeted treatment of chondrosarcoma
Authors: de Jong Yvonne , Monderer David , Brandinelli Emeline , Monchanin Morgane , van den Akker Brendy E. , van Oosterwijk Jolieke G. , Blay Jean Yves , Dutour Aurélie , Bovée Judith V. M. G.
Published: September 2018

Chondrosarcomas are malignant cartilage tumors showing relative resistance to conventional chemo- and radiotherapy. Previous studies showed that chondrosarcoma cells could be sensitized to chemotherapy by inhibiting the Bcl-2 family members Bcl-2, Bcl-xl and Bcl-w using ABT-737. In this study we explored the specific role of Bcl-2 family members to identify the most important player in chondrosarcoma cell survival and chemo resistance. Immunohistochemistry was performed on tissue microarrays containing 137 conventional chondrosarcomas of different grades. Selective inhibition of Bcl-2 (S55746) or Bcl-xl (WEHI-539 or A-1155463) and the combination with doxorubicin or cisplatin was investigated in a panel of 8 chondrosarcoma cell lines using presto blue viability assays and caspase 3/7 glo apoptosis assays. In addition Bcl-2 and Bcl-xl inhibition was investigated in an orthotopic Swarm Rat Chondrosarcoma (SRC) model. Bcl-2 and Bcl-xl were most abundantly expressed in the primary tumors, and expression increased with increasing histological grade. A subset of chondrosarcoma cell lines was sensitive to selective inhibition of Bcl-xl, and synergy was observed with doxorubicin or cisplatin in 3 out of 8 chondrosarcoma cell lines resulting in apoptosis. Conversely, selective inhibition of Bcl-2 was not effective in chondrosarcoma cell lines and could not sensitize to chemotherapy. In vivo, selective inhibition of Bcl-xl, but not Bcl-2 resulted in a decrease in tumor growth rate, even though no sensitization to doxorubicin was observed. These results suggest that among the Bcl-2 family members, Bcl-xl is most important for chondrosarcoma survival. Further research is needed to validate whether single or combination treatment with chemotherapy will be beneficial for chondrosarcoma patients.
Melatonin attenuates detrimental effects of diabetes on the niche of mouse spermatogonial stem cells by maintaining Leydig cells
Authors: Du Zhaoyu , Xu Shuanshuan , Hu Shuxian , Yang Hong , Zhou Zhe , Sidhu Kuldip , Miao Yiliang , Liu Zhonghua , Shen Wei , Reiter Russel J. , Hua Jinlian , Peng Sha
Published: September 2018

Diabetes mellitus affects a large number of men of reproductive age and it usually leads to serious reproductive disorders. However, the underlying mechanisms and specific therapies still remain largely unknown. We observed Leydig cell loss in the testes of diabetic mice. Continuous high glycemic status of testes stimulated expression of Caspase12, Grp78, and Chop, the three ERS response factors; this might induce cell cycle arrest and apoptosis of Leydig cells in response to ERS. In these diabetic mouse models, melatonin alleviated apoptosis of testicular stromal cell induced by ERS, and promoted SSCs self-renewal by recovering Leydig cells secretion of CSF1 after 8 weeks of treatment. To explore the relationship between CSF-1 and ERS in Leydig cells, we treated Leydig tumor cell line with an activator Tuniamycin and an inhibitor 4-Phenylbutyrate of ERS. Our data showed that the CSF-1 expression in mouse Leydig cell lines decreased six-fold while reversely increasing five-fold in the 4-Phenylbutyrate-treated group. Thus, melatonin likely alleviates the loss of Leydig cells in diabetic testes and provides a healthier niche for SSCs to self-renew and continually provide healthy sperm for male fertility.
Interference with lactate metabolism by mmu-miR-320-3p via negatively regulating GLUT3 signaling in mouse Sertoli cells
Authors: Zhang Li-li , Ma Jing , Yang Bo , Zhao Jie , Yan Bin-yuan , Zhang Yuan-qiang , Li Wei
Published: September 2018

Disruption of the nursery function in Sertoli cells (SCs) by reducing lactate production, a preferred energy substrate for developed germ cells (spermatocytes and spermatids), is tightly associated with spermatogenic failure such as SC-only syndrome (SCOS). However, whether this complicated pathogenesis is regulated by certain miRNAs at the post-transcriptional level remain fascinating but largely unknown. Here we show for the first time that mmu-miR-320-3p was exclusively expressed in murine SCs and this expression was significantly induced in busulphan-treated murine testis. The most efficient stimulatory germ cell types for the induction of apoptosis-elicited mmu-miR-320-3p expression were meiotic spermatocytes and haploid spermatids. Functionally, forced expression of the exogenous mmu-miR-320-3p in SCs compromises male fertility by causing oligozoospermia and defection of sperm mobility. Mechanistically, mmu-miR-320-3p negatively regulates lactate production of SCs by directly inhibiting glucose transporter 3 (GLUT3) expression. Thus, dysregulation of mmu-miR-320-3p/GLUT3 cascade and consequently of lactate deficiency may be a key molecular event contributing the germ cell loss by SC dysfunction. Future endeavor in the continuous investigation of this important circulating miRNA may shed novel insights into epigenetic regulation of SCs nursery function and the etiology of azoospermia, and offers novel therapeutic and prognostic targets for SCOS.
Cyclin-dependent kinase 5-mediated phosphorylation of chloride intracellular channel 4 promotes oxidative stress-induced neuronal death
Authors: Guo Dong , Xie Wenting , Xiong Pan , Li Huifang , Wang Siqi , Chen Guimiao , Gao Yuehong , Zhou Jiechao , Zhang Ye , Bu Guojun , Xue Maoqiang , Zhang Jie
Published: September 2018

Oxidative stress can cause apoptosis in neurons and may result in neurodegenerative diseases. However, the signaling mechanisms leading to oxidative stress–induced neuronal apoptosis are not fully understood. Oxidative stress stimulates aberrant activation of cyclin-dependent kinase 5 (CDK5), thought to promote neuronal apoptosis by phosphorylating many cell death-related substrates. Here, using protein pulldown methods, immunofluorescence experiments and in vitro kinase assays, we identified chloride intracellular channel 4 (CLIC4), the expression of which increases during neuronal apoptosis, as a CDK5 substrate. We found that activated CDK5 phosphorylated serine 108 in CLIC4, increasing CLIC4 protein stability, and accumulation. Pharmacological inhibition or shRNA-mediated silencing of CDK5 decreased CLIC4 levels in neurons. Moreover, CLIC4 overexpression led to neuronal apoptosis, whereas knockdown or pharmacological inhibition of CLIC4 attenuated H2O2-induced neuronal apoptosis. These results implied that CLIC4, by acting as a substrate of CDK5, mediated neuronal apoptosis induced by aberrant CDK5 activation. Targeting CLIC4 in neurons may therefore provide a therapeutic approach for managing progressive neurodegenerative diseases that arise from neuronal apoptosis.
Protease-activated receptor 2 signaling modulates susceptibility of colonic epithelium to injury through stabilization of YAP in vivo
Authors: He Longmei , Ma Yiming , Li Weiwei , Han Wenxiao , Zhao Xinhua , Wang Hongying
Published: September 2018

Hippo signaling plays critical roles in intestinal regeneration. However, the mechanisms which regulate its activity in vivo are largely unknown. We hypothesize that protease-activated receptor 2 (PAR2) signaling, which could be activated by trypsin, might affect YAP activity in the setting of tissue damage and regeneration. It is found that knockout of PAR2 severely aggravates the mucosal damage induced by dextran sodium sulfate (DSS) in mouse, which correlated with notable repression of YAP protein in colonic epithelial cells. Although the cytokine expression is reduced, the damage of colonic crypt is more severe after DSS-induced colitis in PAR2-/- mouse. In vitro, PAR2 activation causes the accumulation of YAP, while knockdown of PAR2 with shRNA dramatically represses the expression of YAP protein in different intestinal epithelial cell lines. Moreover, forced expression of YAP significantly reduces the production of reactive oxygen species (ROS) and the sensitivity to nitric oxide-induced apoptosis in PAR2-deficient condition. Further studies show that PAR2 signaling stabilizes YAP protein but independent of Lats. Nevertheless PAR2 activation increased the binding of YAP with protein phosphatase PP1. Inhibition of PP1 with specific siRNA blocked PAR2-induced dephosphorylation of YAP. Taken together, PAR2 signaling might modulate susceptibility of colonic epithelium to injury through stabilization of YAP.
Vascularization converts the lineage fate of bone mesenchymal stem cells to endothelial cells in tissue-engineered bone grafts by modulating FGF2-RhoA/ROCK signaling
Authors: Li Donglin , Cheng Pengzhen , Jiang Huijie , Cao Tianqing , Wang Jimeng , Gao Yi , Lin Yangjing , Wang Chunmei , Zhang Shuaishuai , Li Junqin , Liu Bin , Song Yue , Yang Liu , Pei Guoxian
Published: September 2018

The prevascularization of tissue-engineered bone grafts (TEBGs) has been shown to accelerate capillary vessel ingrowth in bone defect remodeling and to enhance new bone formation. However, the exact mechanisms behind this positive effect remain unknown. Here, we report that basic fibroblast growth factor (FGF2)-Ras homolog gene family member A (RhoA)/Rho-associated protein kinase (ROCK) signaling functions as a molecular switch to regulate the lineage fate of bone mesenchymal stem cells (BMSCs) and that prevascularization promotes the cell fate switch, which contributes to increased bone regeneration with the use of prevascularized TEBGs compared with control TEBGs. Prevascularized TEBGs enhanced the in vivo endothelial differentiation of BMSCs by inhibiting RhoA/ROCK signaling. In vitro data more clearly showed that BMSCs differentiated into von Willebrand factor (vWF)-positive endothelial cells, and FGF2-induced inhibition of RhoA/ROCK signaling played a key role. Our novel findings uncovered a new mechanism that stimulates the increased vascularization of engineered bone and enhanced regeneration by promoting the endothelial differentiation of BMSCs implanted in TEBGs. These results offer a new molecular target to regulate TEBG-induced bone regeneration.
Neuroglobin promotes neurogenesis through Wnt signaling pathway
Authors: Yu Zhanyang , Cheng Chongjie , Liu Yu , Liu Ning , Lo Eng H. , Wang Xiaoying
Published: September 2018

Neuroglobin (Ngb) has been demonstrated by our lab and others to be neuroprotective against neurological disorders including stroke. However, the roles of Ngb in neurogenesis remain elusive. Neurogenesis can occur in adulthood and can be induced by pathological conditions in the brain such as stroke, and significantly contributes to functional recovery, thus enhancing endogenous neurogenesis may be a promising therapeutic strategy for neurodegenerative diseases. In this study we aimed to investigate the roles of Ngb in neurogenesis using Lentivirus overexpressing Ngb (Lv-Ngb). We show that Ngb overexpression promoted the proliferation of neural progenitor cells (NPC) marked by increased neurosphere number and size. Ngb overexpression also enhanced neuronal differentiation of cultured NPC under differentiation conditions. Moreover, subventricular injection of Lv-Ngb in mice after middle cerebral artery occlusion (MCAO) increased PSA-NCAM positive neuroblasts and Tuj1 positive immature neurons, suggesting that Ngb overexpression promotes neurogenesis in mice brain after stroke. We further show that the pro-neurogenesis effect of Ngb overexpression might be mediated through Dvl1 up-regulation, and subsequent activation of Wnt signaling, indicated by increased nuclear localization of beta-catenin. These results suggest that Ngb may play an important role in promoting neurogenesis in neurodegenerative diseases such as stroke, which may eventually benefit the development of stroke therapeutics targeting neurogenesis through Ngb upregulation.
Nitrogen availability regulates topsoil carbon dynamics after permafrost thaw by altering microbial metabolic efficiency
Authors: Chen Leiyi , Liu Li , Mao Chao , Qin Shuqi , Wang Jun , Liu Futing , Blagodatsky Sergey , Yang Guibiao , Zhang Qiwen , Zhang Dianye , Yu Jianchun , Yang Yuanhe
Published: September 2018

Input of labile carbon may accelerate the decomposition of existing soil organic matter (priming effect), with the priming intensity depending on changes in soil nitrogen availability after permafrost thaw. However, experimental evidence for the linkage between the priming effect and post-thaw nitrogen availability is unavailable. Here we test the hypothesis that elevated nitrogen availability after permafrost collapse inhibits the priming effect by increasing microbial metabolic efficiency based on a combination of thermokarst-induced natural nitrogen gradient and nitrogen addition experiment. We find a negative correlation between the priming intensity and soil total dissolved nitrogen concentration along the thaw sequence. The negative effect is confirmed by the reduced priming effect after nitrogen addition. In contrast to the prevailing view, this nitrogen-regulated priming intensity is independent of extracellular enzyme activities but associated with microbial metabolic efficiency. These findings demonstrate that post-thaw nitrogen availability regulates topsoil carbon dynamics through its modification of microbial metabolic efficiency.
Author Correction: Direct evidence for microbial-derived soil organic matter formation and its ecophysiological controls
Authors: Kallenbach Cynthia M. , Frey Serita D. , Grandy A. Stuart
Published: September 2018

In the originally published version of this Article, financial support was not fully acknowledged. The PDF and HTML versions of the Article have now been corrected to include support from the NSF Long-term Ecological Research Program (DEB 1637653) at the Kellogg Biological Station and from Michigan State University AgBioResearch.
Medicinal value of sunflower pollen against bee pathogens
Authors: Giacomini Jonathan J. , Leslie Jessica , Tarpy David R. , Palmer-Young Evan C. , Irwin Rebecca E. , Adler Lynn S.
Published: September 2018

Global declines in pollinators, including bees, can have major consequences for ecosystem services. Bees are dominant pollinators, making it imperative to mitigate declines. Pathogens are strongly implicated in the decline of native and honey bees. Diet affects bee immune responses, suggesting the potential for floral resources to provide natural resistance to pathogens. We discovered that sunflower (Helianthus annuus) pollen dramatically and consistently reduced a protozoan pathogen (Crithidia bombi) infection in bumble bees (Bombus impatiens) and also reduced a microsporidian pathogen (Nosema ceranae) of the European honey bee (Apis mellifera), indicating the potential for broad anti-parasitic effects. In a field survey, bumble bees from farms with more sunflower area had lowerCrithidiainfection rates. Given consistent effects of sunflower in reducing pathogens, planting sunflower in agroecosystems and native habitat may provide a simple solution to reduce disease and improve the health of economically and ecologically important pollinators.
Immunological correlates of mycobacterial growth inhibition describe a spectrum of tuberculosis infection
Authors: O’Shea Matthew K. , Tanner Rachel , Müller Julius , Harris Stephanie A. , Wright Danny , Stockdale Lisa , Stylianou Elena , Satti Iman , Smith Steven G. , Dunbar James , Fletcher Thomas E. , Dedicoat Martin , Cunningham Adam F. , McShane Helen
Published: September 2018

A major contribution to the burden of Tuberculosis (TB) comes from latent Mycobacterium tuberculosis infections (LTBI) becoming clinically active. TB and LTBI probably exist as a spectrum and currently there are no correlates available to identify individuals with LTBI most at risk of developing active disease. We set out to identify immune parameters associated with ex vivo mycobacterial growth control among individuals with active TB disease or LTBI to define the spectrum of TB infection. We used a whole blood mycobacterial growth inhibition assay to generate a functional profile of growth control among individuals with TB, LTBI or uninfected controls. We subsequently used a multi-platform approach to identify an immune signature associated with this profile. We show, for the first time, that patients with active disease had the greatest control of mycobacterial growth, whilst there was a continuum of responses among latently infected patients, likely related to the degree of immune activation in response to bacillary load. Control correlated with multiple factors including inflammatory monocytes, activated and atypical memory B cells, IgG1 responses to TB-specific antigens and serum cytokines/chemokines. Our findings offer a method to stratify subclinical TB infections and the future potential to identify individuals most at risk of progressing to active disease and benefit from chemoprophylaxis.
Subsurface seawater methylmercury maximum explains biotic mercury concentrations in the Canadian Arctic
Authors: Wang Kang , Munson Kathleen M. , Beaupré-Laperrière Alexis , Mucci Alfonso , Macdonald Robie W. , Wang Feiyue
Published: September 2018

Mercury (Hg) is a contaminant of major concern in Arctic marine ecosystems. Decades of Hg observations in marine biota from across the Canadian Arctic show generally higher concentrations in the west than in the east. Various hypotheses have attributed this longitudinal biotic Hg gradient to regional differences in atmospheric or terrestrial inputs of inorganic Hg, but it is methylmercury (MeHg) that accumulates and biomagnifies in marine biota. Here, we present high-resolution vertical profiles of total Hg and MeHg in seawater along a transect from the Canada Basin, across the Canadian Arctic Archipelago (CAA) and Baffin Bay, and into the Labrador Sea. Total Hg concentrations are lower in the western Arctic, opposing the biotic Hg distributions. In contrast, MeHg exhibits a distinctive subsurface maximum at shallow depths of 100–300 m, with its peak concentration decreasing eastwards. As this subsurface MeHg maximum lies within the habitat of zooplankton and other lower trophic-level biota, biological uptake of subsurface MeHg and subsequent biomagnification readily explains the biotic Hg concentration gradient. Understanding the risk of MeHg to the Arctic marine ecosystem and Indigenous Peoples will thus require an elucidation of the processes that generate and maintain this subsurface MeHg maximum.
Crown ethers reverse P-glycoprotein-mediated multidrug resistance in cancer cells
Authors: Guberović Iva , Marjanović Marko , Mioč Marija , Ester Katja , Martin-Kleiner Irena , Šumanovac Ramljak Tatjana , Mlinarić-Majerski Kata , Kralj Marijeta
Published: September 2018

Multidrug resistance (MDR) is a widespread phenomenon exhibited by many cancers and represents a fundamental obstacle for successful cancer treatments. Tumour cells commonly achieve MDR phenotype through overexpression and/or increased activity of ABC transporters. P-glycoprotein transporter (P-gp, ABCB1) is a major cause of MDR and therefore represents a valuable target for MDR reversal. Several naturally occurring potassium ionophores (e.g. salinomycin) were shown to inhibit P-gp effectively. We have previously shown antitumour activity of a number of 18-crown-6 ether compounds that transport potassium ions across membranes. Here we present data on P-gp inhibitory activity of 16 adamantane-substituted monoaza- and diaza-18-crown-6 ether compounds, and their effect on MDR reversal in model cell lines. We show that crown ether activity depends on their lipophilicity as well as on the linker to adamantane moiety. The most active crown ethers were shown to be more effective in sensitising MDR cells to paclitaxel and adriamycin than verapamil, a well-known P-gp inhibitor. Altogether our data demonstrate a novel use of crown ethers for inhibition of P-gp and reversal of MDR phenotype.