bluuebunny/crossref_metadata_2025 huggingface dataset:
Family Involvement in Middle Management and Its Impact on the Labor Productivity of Family Firms
Authors: Hu Qiongjing , Zhang Yanlong , Yao Jingjing
Published: May 2018

Family business owners and researchers tend to overwhelmingly focus on the top-level structure of firms but ignore the middle-level practice – involving family members in the middle-management team. Compared to top managers at the strategic apex, middle-level managers are mainly responsible for internal operations and control, and the composition of the middle-management team has an immediate and direct impact on the overall workforce efficiency of family firms. Integrating agency theory and organizational justice perspective, we proposed that family involvement in middle management would have a negative impact on the labor productivity of family firms. We further corroborated this effect by identifying three boundary conditions at the individual (i.e., familial CEO), organizational (i.e., firm size), and regional (i.e., labor mobility) levels. Using a sample of 1,284 privately owned family firms in China, we found that family involvement in middle management, measured as the percentage of familial middle-level managers, was negatively associated with labor productivity. Furthermore, this negative relationship existed only when the CEO is a family member rather than a professional manager, when the size of the firm is large rather than small, or when the firm is located in regions with low rather than high labor mobility. These findings contribute to family business literature and provide practical implications for human resource management in family firms.
Integrated Cambrian biostratigraphy and carbon isotope chemostratigraphy of the Grönhögen-2015 drill core, Öland, Sweden
Authors: AHLBERG PER , LUNDBERG FRANS , ERLSTRÖM MIKAEL , CALNER MIKAEL , LINDSKOG ANDERS , DAHLQVIST PETER , JOACHIMSKI MICHAEL M.
Published: May 2018

The Grönhögen-2015 core drilling on southern Öland, Sweden, penetrated 50.15 m of Cambrian Series 3, Furongian and Lower–Middle Ordovician strata. The Cambrian succession includes the Äleklinta Member (upper Stage 5) of the Borgholm Formation and the Alum Shale Formation (Guzhangian–Tremadocian). Agnostoids and trilobites allowed subdivision of the succession into eight biozones, in ascending order: the uppermost Cambrian Series 3 (Guzhangian) Agnostus pisiformis Zone and the Furongian Olenus gibbosus, O. truncatus, Parabolina spinulosa, Sphaerophthalmus? flagellifer, Ctenopyge tumida, C. linnarssoni and Parabolina lobata zones. Conspicuous lithologic unconformities and the biostratigraphy show that the succession is incomplete and that there are several substantial gaps of variable magnitudes. Carbon isotope analyses (δ13Corg) through the Alum Shale Formation revealed two globally significant excursions: the Steptoean Positive Carbon Isotope Excursion (SPICE) in the lower–middle Paibian Stage, and the negative Top of Cambrian Excursion (TOCE), previously referred to as the HERB Event, in Stage 10. The δ13Corg chemostratigraphy is tied directly to the biostratigraphy and used for an improved integration of these excursions with the standard agnostoid and trilobite zonation of Scandinavia. Their relations to that of coeval successions in Baltoscandia and elsewhere are discussed. The maximum amplitudes of the SPICE and TOCE in the Grönhögen succession are comparable to those recorded in drill cores retrieved from Scania, southern Sweden. The results of this study will be useful for assessing biostratigraphic relations between shale successions and carbonate facies on a global scale.
Deciphering the behaviour manipulation imposed by a virus on its parasitoid host: insights from a dual transcriptomic approach
Authors: Varaldi J. , Lepetit D.
Published: May 2018

Behaviour manipulation imposed by parasites is a fascinating phenomenon but our understanding is still very limited. We studied the interaction between a virus and the parasitic waspLeptopilina boulardithat attacksDrosophilalarvae. Wasps usually refrain to lay eggs into already parasitized hosts (superparasitism avoidance). On the contrary, females infected by the Leptopilina boulardi Filamentous Virus (LbFV) are much more incline to superparasitize. Interestingly, the host-sharing induced by this behaviour modification leads to the horizontal transmission of the virus, thus increasing its fitness at the expense of that of the wasp. To better understand the mechanisms underlying this behaviour manipulation, we studied by RNA sequencing the meta-transcriptome of LbFV and the parasitic wasp both in the abdomen and in the head. We found that the abundance of viral transcripts was independent of the wasp strain but strongly differed between tissues. Based on the tissue pattern of expression, we identified a set of 20 viral genes putatively involved in the manipulation process. In addition, we identified a set of wasp genes deregulated in the presence of the virus either in the abdomen or in the head, including genes with annotations suggesting involvement in behaviour (i.e. Potassium-channel protein). This dataset gives new insights into the behaviour manipulation and on the genetic basis of superparasitism in parasitoids.
On the SL(2, C)-representation rings of free abelian groups
Authors: SATOH TAKAO
Published: May 2018

In this paper, we study “the ring of component functions” of SL(2, C)-representations of free abelian groups. This is a subsequent research of our previous work [11] for free groups. We introduce some descending filtration of the ring, and determine the structure of its graded quotients.

Then we give two applications. In [30], we constructed the generalized Johnson homomorphisms. We give an upper bound on their images with the graded quotients. The other application is to construct a certain crossed homomorphisms of the automorphism groups of free groups. We show that our crossed homomorphism induces Morita's 1-cocycle defined in [22]. In other words, we give another construction of Morita's 1-cocyle with the SL(2, C)-representations of the free abelian group.
Introduction: The “Singapore model” and China's Neo-Authoritarian Dream
Authors: Ortmann Stephan , Thompson Mark R.
Published: May 2018

This special section deals with China's longstanding fascination with Singapore's development experience that has preoccupied post-Maoist leaders from Deng Xiaoping to Xi Jinping despite the obvious differences between the tiny Southeast Asian city-state and the most populous country on earth. In particular, there is great Chinese interest in Singapore's success in combining effective governance and efficient state capitalism with stable one-party dominant rule. As a consequence, Chinese observers paid much less attention to electoral democracies that were well-governed states with mature economies.
Power and Populism: What the Singapore Model Means for the Chinese Dream
Authors: Ho Benjamin Tze Ern
Published: May 2018

Singapore's political system is sometimes criticized by proponents of liberal democracy as being highly authoritarian and inhibiting of individual freedom. Yet, as the recent 2015 general elections show, Singaporeans have largely consented to such a model as a legitimate social contract between themselves and the government. Given that the Singapore model is widely studied by Chinese officials as a positive pattern for governance, what do the latest results say about the future of the Chinese governing system, and to what extent is the Communist Party able to wield power while catering to populist sentiments, in particular the achievement of the Chinese dream?
Prevalence and predictors of major depressive disorder in bereaved caregivers at 6 and 13 months
Authors: Kim Seon-Young , Kim Seung-Jeon , Kim Jae-Min , Kim Sung-Wan , Shin Il-Seon , Shim Hyun-Jeong , Cho Sang-Hee , Chung Ik-Joo , Yoon Jin-Sang
Published: May 2018

Objective

Depressive symptoms are common in bereaved caregivers; however, there have been few prospective studies using a structured interview. This study investigated the prevalence and preloss predictors of major depressive disorder (MDD) in bereaved caregivers of patients in a palliative care unit.

Method

This prospective cohort study collected caregiver sociodemographic and psychological data before the death of a palliative care unit patient, including MDD, care-burden, coping style, and hopeful attitude. Postloss MDD was assessed 6 and 13 months after death, and a multivariate logistic regression analysis was conducted to identify its predictors.

Result

Of 305 caregivers contacted, 92 participated in this study. The prevalence of preloss MDD was 21.8%; the prevalences of postloss MDD were 34.8% and 24.7% at 6 and 13 months, respectively. Preloss MDD predicted postloss MDD at 6 months (odds ratio [OR] = 5.38, 95% confidence interval [CI95%] = 1.29, 22.43); preloss nonhopeful attitude and unemployment status of caregivers predicted postloss MDD at 13 months (OR = 8.77, CI95% = 1.87, 41.13 and OR = 7.10, CI95% = 1.28, 39.36, respectively).

Significance of results

Approximately 35% of caregivers suffered from MDD at 6 months postloss, but the prevalence of MDD decreased to about 25% at 13 months. Preloss MDD significantly predicted postloss MDD at 6 months, whereas hopeful attitude and unemployment at baseline were significantly associated with postloss MDD at 13 months.
What does the latest meta-analysis really tell us about antidepressants?
Authors: Moncrieff J.
Published: May 2018

A recent meta-analysis of antidepressant trials is the largest conducted to date. Although it claims to prove antidepressant effectiveness beyond dispute, the main outcome is response rates, which are derived from continuous data in a process that can inflate differences between groups. The standardised mean difference of 0.3 is in line with other meta-analyses that show small differences between antidepressants and placebo that are unlikely to be clinically significant. Other factors likely to exaggerate the effects are discussed, and evidence on associations between antidepressant effects and severity and outcomes of long-term treatment is considered. Clinicians need to have open discussions with patients about the limitations of antidepressant research, the lack of evidence that antidepressants correct a chemical imbalance or other brain abnormality, and the range of adverse effects and mental and physical alterations they can produce.
Recurrent Activation of Neural Circuits during Attention to Global and Local Visual Information
Authors: Iglesias-Fuster Jorge , Piña-Novo Daniela , Ontivero-Ortega Marlis , Lage-Castellanos Agustín , Valdés-Sosa Mitchell
Published: May 2018

The attentional selection of different hierarchical level within compound (Navon) figures has been studied with event related potentials (ERPs), by controlling the ERPs obtained during attention to the global or the local echelon. These studies, using the canonical Navon figures, have produced contradictory results, with doubts regarding the scalp distribution of the effects. Moreover, the evidence about the temporal evolution of the processing of these two levels is not clear. Here, we unveiled global and local letters at distinct times, which enabled separation of their ERP responses. We combine this approach with the temporal generalization methodology, a novel multivariate technique which facilitates exploring the temporal structure of these ERPs. Opposite lateralization patterns were obtained for the selection negativities generated when attending global and local distracters (D statistics, p < .005), with maxima in right and left occipito-temporal scalp regions, respectively (η2 = .111, p < .01; η2 = .042, p < .04). However, both discrimination negativities elicited when comparing targets and distractors at the global or the local level were lateralized to the left hemisphere (η2 = .25, p < .03 and η2 = .142, p < .05 respectively). Recurrent activation patterns were found for both global and local stimuli, with scalp topographies corresponding to early preparatory stages reemerging during the attentional selection process, thus indicating recursive attentional activation. This implies that selective attention to global and local hierarchical levels recycles similar neural correlates at different time points. These neural correlates appear to be mediated by visual extra-striate areas.
Measurements of Sound Velocity of Liquid Fe‐11.8 wt % S up to 211.4 GPa and 6,150 K
Authors: Huang H. , Leng C. , Wang Q. , Yang G. , Hu X. , Wu Y. , Liu X. , Fei Y.
Published: May 2018

Using the dynamic compression technique, the sound velocities of Fe‐11.8 wt % S were measured up to 211.4 (4.5) GPa and 6,150 K. Discontinuities both in shock velocity and sound velocity indicate that Fe‐11.8 wt % S completely melts at a pressure of 111.3 (2.3) GPa. By the energy conservation law, the calculated liquidus temperature is about 2,500 (300) K. Extrapolated to the inner‐core boundary based on the Lindeman law, the liquidus temperature of Fe‐11.8 wt % S is 4,300 (300) K. We developed a thermodynamic model fit to the experimental data, which allows calculation of the densities and sound velocities of liquid Fe‐S under core conditions. For liquid Fe‐11.8 wt % S and Fe‐10 wt % S, good agreement was achieved between the extrapolations using our model and experimental measurements at very low pressure. Under the conditions of the outer core, the densities and bulk sound velocities of Fe‐10 wt % S provide a good fit to observed seismic profiles of Earth's core. Our results imply that an upper limit of 10 wt % S content in Earth's core satisfies the geophysical constraints. Simultaneously considering other geochemical constraints, the outer core may contain about 6 wt % sulfur and 4 wt % silicon.
Acoustic Emission in a Laboratory: Mechanism of Microearthquakes Using Alternative Source Models
Authors: Petružálek M. , Jechumtálová Z. , Kolář P. , Adamová P. , Svitek T. , Šílený J. , Lokajíček T.
Published: May 2018

Here a shear‐tensile crack (STC) model is presented as suitable for acoustic emission (AE) events. Experimental data were obtained from a uniaxial compression test performed on a Westerly Granite specimen using a 14‐channel AE monitoring system. The advantages of the STC versus a traditional MT (moment tensor) approach are as follows: (i) it is a physical source, contrary to the MT, since the STC describes the straight and simple fracture modes anticipated inside a loaded sample, namely, the shear slip and both the opening and closing tensile cracks; and (ii) it is simpler because it is described by fewer parameters (five instead of the six required for an unconstrained MT), which is essential for solving the inverse problem. The presented STC procedure was tested on 38 AE events selected over a range of 50–98% for the uniaxial compressive strength. As compared to the MT model, the STC model displayed a similar fit for input data while providing far smaller confidence regions. The results indicate a more certain determination for the mechanism of orientation and improved reliability for the decomposition components. In addition, use of STC model allowed better distinction between tension and shear type for AE events, which may be crucial for recognizing an approaching failure. For our experiment, application of the STC model proved to be useful for recognizing the threshold of unstable microcracking and indicative for determining the failure plain orientation.
Transdimensional Electrical Resistivity Tomography
Authors: Galetti E. , Curtis A.
Published: May 2018

This paper shows that imaging the interior of solid bodies with fully nonlinear physics can be highly beneficial compared to imaging with the equivalent linearized tomographic methods and that this is true for a variety of different types of physics. Including full nonlinearity provides interpretable uncertainties and far greater depth of image penetration into unknown targets such as the Earth's subsurface. We use an adaptively parameterized Monte Carlo method to invert electrical resistivity data for the conductivity structure of the Earth and demonstrate the method on two field data sets. Key results include the observation of directly interpretable uncertainty loops which define possible geometrical variations in the edges of isolated anomalies, hence quantifying the spatial resolution of these boundaries. These topologies of uncertainties are similar to those observed when performing fully nonlinear seismic traveltime tomography. This shows that loop‐like uncertainty topologies are expected in the solutions to a wide variety of tomographic problems, using a variety of data types and hence laws of physics (here the Laplace equation; in previous work the Eikonal or ray equations). We also show that the depth to which we can construct a tomographic image using electrical data is extended by up to a factor of 8 using nonlinear methods compared to linearized inversion using common standard linearized programs. These advantages come at the cost of significantly increased computation. All of these results are illustrated on both synthetic and real data examples.
Role of the Madden‐Julian Oscillation in the Transport of Smoke From Sumatra to the Malay Peninsula During Severe Non‐El Niño Haze Events
Authors: Koplitz S. N. , Mickley L. J. , Jacob D. J. , Marlier M. E. , DeFries R. S. , Gaveau D. L. A. , Locatelli B. , Reid J. S. , Xian P. , Myers S. S.
Published: May 2018

In June 2013, the Malay Peninsula experienced severe smoke pollution, with daily surface particulate matter (PM) concentrations in Singapore greater than 350 μg/m3, over 2 times the air quality standard for daily mean PM10 set by the U.S. Environmental Protection Agency. Unlike most haze episodes in the Malay Peninsula in recent decades (e.g., the September 2015 event), the June 2013 haze occurred in the absence of an El Niño, during negative Indian Ocean Dipole conditions, with smoke carried eastward to the Peninsula from fires in the Riau province of central Sumatra. We show that June 2013 was not an exceptional event; inspection of visibility data during 2005–2015 reveals two other severe haze events in the Malay Peninsula (August 2005 and October 2010) occurring under similar conditions. Common to all three events was a combination of anomalously strong westerly winds over Riau province concurrent with late phases of the Real‐Time Multivariate Madden‐Julian Oscillation Index, during negative phases of the Indian Ocean Dipole. Our work suggests that identifying the meteorological mechanism driving these westerly wind anomalies could help stakeholders prepare for future non‐El Niño haze events in Singapore and the Malay Peninsula.
Calibrating Climate Model Ensembles for Assessing Extremes in a Changing Climate
Authors: Herger Nadja , Angélil Oliver , Abramowitz Gab , Donat Markus , Stone Dáithí , Lehmann Karsten
Published: May 2018

Climate models serve as indispensable tools to investigate the effect of anthropogenic emissions on current and future climate, including extremes. However, as low‐dimensional approximations of the climate system, they will always exhibit biases. Several attempts have been made to correct for biases as they affect extremes prediction, predominantly focused on correcting model‐simulated distribution shapes. In this study, the effectiveness of a recently published quantile‐based bias correction scheme, as well as a new subset selection method introduced here, are tested out‐of‐sample using model‐as‐truth experiments. Results show that biases in the shape of distributions tend to persist through time, and therefore, correcting for shape bias is useful for past and future statements characterizing the probability of extremes. However, for statements characterized by a ratio of the probabilities of extremes between two periods, we find that correcting for shape bias often provides no skill improvement due to the dominating effect of bias in the long‐term trend. Using a toy model experiment, we examine the relative importance of the shape of the distribution versus its position in response to long‐term changes in radiative forcing. It confirms that the relative position of the two distributions, based on the trend, is at least as important as the shape. We encourage the community to consider all model biases relevant to their metric of interest when using a bias correction procedure and to construct out‐of‐sample tests that mirror the intended application.
Cryo-EM structure of the ASIC1a–mambalgin-1 complex reveals that the peptide toxin mambalgin-1 inhibits acid-sensing ion channels through an unusual allosteric effect
Authors: Sun Demeng , Yu You , Xue Xiaobin , Pan Man , Wen Ming , Li Siyu , Qu Qian , Li Xiaorun , Zhang Longhua , Li Xueming , Liu Lei , Yang Maojun , Tian Changlin
Published: May 2018

Acid-sensing ion channels (ASICs) are neuronal voltage-independent Na+ channels that are activated by extracellular acidification. ASICs play essential roles in a wide range of physiological processes, including sodium homeostasis, synaptic plasticity, neurodegeneration, and sensory transduction. Mambalgins, a family of three-finger toxins isolated from black mamba venom, specifically inhibit ASICs to exert strong analgesic effects in vivo, thus are thought to have potential therapeutic values against pain. However, the interaction and inhibition mechanism of mambalgin on ASICs remains elusive. Here, we report a cryo-electron microscopy (cryo-EM) structure of chicken ASIC1a (cASIC1a) in complex with mambalgin-1 toxin at 5.4 Å resolution. Our structure provides the first experimental evidence that mambalgin-1 interacts directly with the extracellular thumb domain of cASIC1a, rather than inserting into the acid-sensing pocket, as previously reported. Binding of mambalgin-1 leads to relocation of the thumb domain that could disrupt the acidic pocket of cASIC1a, illustrating an unusual inhibition mechanism of toxins on ASIC channels through an allosteric effect. These findings establish a structural basis for the toxicity of the mambalgins, and provide crucial insights for the development of new optimized inhibitors of ASICs.
Gas41 links histone acetylation to H2A.Z deposition and maintenance of embryonic stem cell identity
Authors: Hsu Chih-Chao , Zhao Dan , Shi Jiejun , Peng Danni , Guan Haipeng , Li Yuanyuan , Huang Yaling , Wen Hong , Li Wei , Li Haitao , Shi Xiaobing
Published: May 2018

The histone variant H2A.Z is essential for maintaining embryonic stem cell (ESC) identity in part by keeping developmental genes in a poised bivalent state. However, how H2A.Z is deposited into the bivalent domains remains unknown. In mammals, two chromatin remodeling complexes, Tip60/p400 and SRCAP, exchange the canonical histone H2A for H2A.Z in the chromatin. Here we show that Glioma Amplified Sequence 41 (Gas41), a shared subunit of the two H2A.Z-depositing complexes, functions as a reader of histone lysine acetylation and recruits Tip60/p400 and SRCAP to deposit H2A.Z into specific chromatin regions including bivalent domains. The YEATS domain of Gas41 bound to acetylated histone H3K27 and H3K14 both in vitro and in cells. The crystal structure of the Gas41 YEATS domain in complex with the H3K27ac peptide revealed that, similar to the AF9 and ENL YEATS domains, Gas41 YEATS forms a serine-lined aromatic cage for acetyllysine recognition. Consistently, mutations in the aromatic residues of the Gas41 YEATS domain abrogated the interaction. In mouse ESCs, knockdown of Gas41 led to flattened morphology of ESC colonies, as the result of derepression of differentiation genes. Importantly, the abnormal morphology was rescued by expressing wild-type Gas41, but not the YEATS domain mutated counterpart that does not recognize histone acetylation. Mechanically, we found that Gas41 depletion led to reduction of H2A.Z levels and a concomitant reduction of H3K27me3 levels on bivalent domains. Together, our study reveals an essential role of the Gas41 YEATS domain in linking histone acetylation to H2A.Z deposition and maintenance of ESC identity.
Sea cucumber genome provides insights into saponin biosynthesis and aestivation regulation
Authors: Li Yuli , Wang Ruijia , Xun Xiaogang , Wang Jing , Bao Lisui , Thimmappa Ramesha , Ding Jun , Jiang Jingwei , Zhang Liheng , Li Tianqi , Lv Jia , Mu Chuang , Hu Xiaoli , Zhang Lingling , Liu Jing , Li Yuqiang , Yao Lijie , Jiao Wenqian , Wang Yangfan , Lian Shanshan , Zhao Zelong , Zhan Yaoyao , Huang Xiaoting , Liao Huan , Wang Jia , Sun Hongzhen , Mi Xue , Xia Yu , Xing Qiang , Lu Wei , Osbourn Anne , Zhou Zunchun , Chang Yaqing , Bao Zhenmin , Wang Shi
Published: May 2018

Echinoderms exhibit several fascinating evolutionary innovations that are rarely seen in the animal kingdom, but how these animals attained such features is not well understood. Here we report the sequencing and analysis of the genome and extensive transcriptomes of the sea cucumber Apostichopus japonicus, a species from a special echinoderm group with extraordinary potential for saponin synthesis, aestivation and organ regeneration. The sea cucumber does not possess a reorganized Hox cluster as previously assumed for all echinoderms, and the spatial expression of Hox7 and Hox11/13b potentially guides the embryo-to-larva axial transformation. Contrary to the typical production of lanosterol in animal cholesterol synthesis, the oxidosqualene cyclase of sea cucumber produces parkeol for saponin synthesis and has “plant-like” motifs suggestive of convergent evolution. The transcriptional factors Klf2 and Egr1 are identified as key regulators of aestivation, probably exerting their effects through a clock gene-controlled process. Intestinal hypometabolism during aestivation is driven by the DNA hypermethylation of various metabolic gene pathways, whereas the transcriptional network of intestine regeneration involves diverse signaling pathways, including Wnt, Hippo and FGF. Decoding the sea cucumber genome provides a new avenue for an in-depth understanding of the extraordinary features of sea cucumbers and other echinoderms.
Genitopatellar syndrome: the first reported case in Japan
Authors: Okano Satomi , Miyamoto Akie , Fukuda Ikue , Tanaka Hajime , Hata Kenichiro , Kaname Tadashi , Matsubara Yoichi , Makita Yoshio
Published: May 2018

Genitopatellar syndrome (GPS) is mainly characterized by an absence of patellae, congenital flexion contractures of the lower limbs, psychomotor retardation, and anomalies of the external genitalia and kidneys. We report an 18-year-old female with a novel heterozygous truncating mutation in exon 17 of the KAT6B gene [MC_000010.11:c.3603_3606 del, p.Arg1201fs]. This is the first report of typical GPS in a Japanese individual. The details of our findings may contribute to elucidating the mechanism underlying GPS-specific clinical features.
A turn-on fluorescent formaldehyde probe regulated by combinational PET and ICT mechanisms for bioimaging applications
Authors: Yang Xueling , He Longwei , Xu Kaixin , Yang Yunzhen , Lin Weiying
Published: May 2018

A turn-on fluorescent formaldehyde probe regulated by combinational PET and ICT mechanisms was judiciously constructed for bio-applications.
A novel method for geographical origin identification ofTetrastigma hemsleyanum(Sanyeqing) by near-infrared spectroscopy
Authors: Lin Weiqun , Chai Qinqin , Wang Wu , Li Yurong , Qiu Bin , Peng Xin , Lai Tianyue , Huang Jie , Lin Zhenyu
Published: May 2018

Tetrastigma hemsleyanumDiels et Gilg (T. hemsleyanum), also known as Sanyeqing in Chinese, is a rare medicinal herb.
Highly-efficient and low-temperature perovskite solar cells by employing a Bi-hole transport layer consisting of vanadium oxide and copper phthalocyanine
Authors: Lei Ting , Dong Hua , Xi Jun , Niu Yong , Xu Jie , Yuan Fang , Jiao Bo , Zhang Wenwen , Hou Xun , Wu Zhaoxin
Published: May 2018

In this article, an inorganic–organic bilayer hole transport layer (B-HTL) is designed and utilized in planar perovskite solar cells.
Potential for improved transport in core–shell CuInS2 nanoparticle solar cells from an Ag surface termination
Authors: Hu Yicong , Patterson Rob , Lee-Chin Robert , Zheng Jianghui , Song Ning , Hu Long , Conibeer Gavin , Huang Shujuan
Published: May 2018

Improvements in charge carrier transport and equivalent photoluminescence were obtained for CuInS2 nanoparticles with Ag-surface termination in photovoltaic devices.
Energy transfer mechanism dominated by the doping location of activators in rare-earth upconversion nanoparticles
Authors: Sun Liyuan , Li Luoyuan , Gao Rongyao , Tang Keyun , Fu Limin , Ai Xi-Cheng , Zhang Jian-Ping
Published: May 2018

Different core–shell upconversion nanoparticles were prepared to investigate the energy transfer mechanism dominated by the location of activators.
Observation of middle-sized metal clusters in femtosecond laser ablation plasmas through nonlinear optics
Authors: Oujja M. , Izquierdo J. G. , Bañares L. , de Nalda R. , Castillejo M.
Published: May 2018

Clusters detected in femtosecond laser plasmas of metals through frequency conversion.
Metal solution precursors: their role during the synthesis of MoVTeNb mixed oxide catalysts
Authors: Valente Jaime S. , Maya-Flores Etel , Armendáriz-Herrera Héctor , Quintana-Solórzano Roberto , López Nieto José M.
Published: May 2018

Crystals of MoVTeNbOxM1 phase for the ODH of ethane to ethylene.
Structural, optical and X-ray attenuation properties of Tb3+:BaxCe1−xF3−x (x = 0.18–0.48) nanospheres synthesized in polyol medium
Authors: González-Mancebo Daniel , Becerro Ana Isabel , Genevois Cécile , Allix Mathieu , Corral Ariadna , Parrado-Gallego Angel , Ocaña Manuel
Published: May 2018

Uniform Tb3+:BaxCe1−xF3−x nanospheres obtained in polyol medium form colloidal suspensions in water and show an intense green emission under UV excitation and excellent X-ray attenuation properties.
Novel single component tri-rare-earth emitting MOF for warm white light LEDs
Authors: Li Hui , Liu Hong-Bin , Tao Xiao-Min , Su Jian , Ning Ping-Fan , Xu Xiu-Fang , Zhou Yu , Gu Wen , Liu Xin
Published: May 2018

WLED devices were fabricated with the MOF as a single phase phosphor, and have good warm white light quality even at high temperatures.
Closing the gap between small and smaller: towards a framework to analyse nano- and microplastics in aqueous environmental samples
Authors: Mintenig S. M. , Bäuerlein P. S. , Koelmans A. A. , Dekker S. C. , van Wezel A. P.
Published: May 2018

Environmental nanoplastic concentrations are fairly unknown, to tackle this we propose a framework determining a broad size spectrum of plastics.
Performance of a seawater-driven forward osmosis process for pre-concentrating digested sludge centrate: organic enrichment and membrane fouling
Authors: Vu Minh T. , Ansari Ashley J. , Hai Faisal I. , Nghiem Long D.
Published: May 2018

This study demonstrated the potential of seawater-driven forward osmosis for enriching organic matter in digested sludge centrate.
[bmIm]Br catalyzed tandem construction of C–C and C–O bonds: a concise, convenient and atom-economical strategy for the synthesis of spiropyranopiperidine derivatives
Authors: Waseem Malik A. , Rather Rafiq A. , Saquib Mohammad , Ibad Afshan , Ibad Farah , Ansari Khursheed , Khuroo M. A. , Assiri Mohammed A. , Siddiqui I. R.
Published: May 2018

A versatile one-pot three component synthetic protocol for chiral heterocyclic scaffolds has been disclosed.
Direct imaging and manipulation of ionic diffusion in mixed electronic–ionic conductors
Authors: Op de Beeck J. , Labyedh N. , Sepúlveda A. , Spampinato V. , Franquet A. , Conard T. , Vereecken P. M. , Celano U.
Published: May 2018

Next generation Li-ion battery cathodes are studied providing direct correlation between electrical, structural and chemical properties.
Rational design of an anchoring peptide for high-efficiency and quantitative modification of peptides and DNA strands on gold nanoparticles
Authors: Li Xin-Yi , Feng Fu-Yan , Zhou Xiao-Dong , Hu Ji-Ming
Published: May 2018

New design criteria for the anchor were established to provide a high-efficiency approach to modify peptides or DNAs on AuNPs.
Photo-driven nanoactuators based on carbon nanocoils and vanadium dioxide bimorphs
Authors: Ma He , Zhang Xinping , Cui Ruixue , Liu Feifei , Wang Meng , Huang Cuiying , Hou Jiwei , Wang Guang , Wei Yang , Jiang Kaili , Pan Lujun , Liu Kai
Published: May 2018

Photo-driven actuators are highly desirable in various smart systems owing to the advantages of wireless control and possible actuation by solar energy.
Graft-modified cellulose nanocrystals as CO2-switchable Pickering emulsifiers
Authors: Glasing J. , Jessop P. G. , Champagne P. , Cunningham M. F.
Published: May 2018

Cellulose nanocrystals (CNC) grafted with <25 wt% PDEAEMA or PDMAPMAm were used as CO2-switchable Pickering emulsifiers for the reversible emulsification/demulsification of oil and water.
Visible-light photocatalytic trifluoromethylthiolation of aryldiazonium salts: conversion of amino group into trifluoromethylthiol group
Authors: Zhao Xia , Zheng Xiancai , Tian Miaomiao , Tong Yifan , Yang Bo , Wei Xianfu , Qiu Di , Lu Kui
Published: May 2018

A visible-light photocatalytic trifluoromethylthiolation of aryl amine through in situ generation of aryldiazonium salts with S-trifluoromethyl 4-methoxylbenzenesulfonothioate was developed.
Student-centred active learning approaches to teaching quantum chemistry and spectroscopy: quantitative results from a two-year action research study
Authors: Partanen Lauri
Published: May 2018

In this article, I propose a student-centred approach to teaching quantum chemistry and spectroscopy at the bachelor-level that extends active learning principles outside course lectures. The aim is to elucidate what type of methodology is most appropriate and efficient for this context and student population, and how this incorporation of active learning elements impacts learning. Three quantitative learning indicators are used to measure the effectiveness of the proposed approach, including exercise points obtained by the students, exam results, and the results of a conceptual inventory administered both at the beginning and the end of the course. The proposed model resulted in substantial improvement in learning outcomes compared to a previous class where active learning elements were confined mostly to the course lectures and a traditionally taught class. The model can be generalised to any subject where both quantitative and qualitative understanding is required. Thus, in addition to providing further support for the effectiveness of active learning approaches in science, this study shows the benefits of applying these approaches to exercises and other course tasks besides lectures.
The effect of motivation on the choice of chemistry in secondary schools: adaptation and validation of the Science Motivation Questionnaire II to Spanish students
Authors: Ardura Diego , Pérez-Bitrián Alberto
Published: May 2018

The present study aims to analyse the effect of motivational variables and previous academic achievement on students’ future choice of chemistry once this subject becomes optional in the educational system. Toward this goal, the translation and adaptation of the Science Motivation Questionnaire II (SMQII) has been undertaken in our investigation to measure students’ motivation towards physics and chemistry. The sample comprised 1060 secondary school Spanish students divided into two groups: 695 students who chose the subject when it became optional for the first time and 365 who decided to leave it. Factor analysis confirmed the original structure of latent variables in our sample, providing validity for this adaptation to a new language and context. A segmentation analysis confirmed that career motivation was the best predictor of students’ retention in physics and chemistry before previous academic achievement and the rest of the motivational variables. Although significant gender differences were found in self-efficacy and self-determination, these seem not to be relevant in students’ choice.
Chemistry topics posing incommensurate difficulty to students with low math aptitude scores
Authors: Rosa Vanessa , Lewis Scott E.
Published: May 2018

The identification of students at risk for academic failure in undergraduate chemistry courses has been heavily addressed in the literature. Arguably one of the strongest and most well-supported predictors of undergraduate success in chemistry is the mathematics portion of the SAT (SAT-M), a college-entrance, standardized test administered by the College Board. While students scoring in the bottom quartile of the SAT-M (herein referred to as at-risk) perform significantly worse on first-semester chemistry assessments, little is known of the topics on which these students differentially struggle. The purpose of this study is to provide insight as to which first-semester chemistry topics present an incommensurate challenge to at-risk students. Students were identified as either at-risk or not at-risk via SAT-M scores. Students’ assessment responses were collected across four semesters of first-semester chemistry courses at a large, public university (N = 5636). At-risk students struggled consistently across all topics but disproportionately with mole concept and stoichiometry. Analyzing the trend in topics suggests that the struggles of at-risk students are not entirely attributable to topics that rely heavily on algorithms or algebraic math. Moreso, at-risk students found to have performed well on mole concept and stoichiometry went on to perform similarly as their not at-risk peers. The results support an instructional emphasis on these topics with reviewed literature offering promising, practical options to better serve at-risk students and broaden representation in the sciences.
Layered tin sulfide and selenide anode materials for Li- and Na-ion batteries
Authors: Wei Zengxi , Wang Lei , Zhuo Ming , Ni Wei , Wang Hongxia , Ma Jianmin
Published: May 2018

In this review, we report the recent research progress in the area of design and synthesis of tin sulfide and selenide (SnS, SnS2, SnSe, and SnSe2) based anode materials for Li-ion batteries and Na-ion batteries.
Puzzling Lyman-alpha line profiles in green pea galaxies
Authors: Orlitová I. , Verhamme A. , Henry A. , Scarlata C. , Jaskot A. , Oey M. S. , Schaerer D.
Published: May 2018

Context. The Lyman-alpha (Lyα) line of hydrogen is of prime importance for detecting galaxies at high redshift. For a correct data interpretation, numerical radiative transfer models are necessary due to Lyα resonant scattering off neutral hydrogen atoms.

Aims. Recent observations have discovered an escape of ionizing Lyman-continuum radiation from a population of compact, actively star-forming galaxies at redshift z ~ 0.2−0.3, also known as “green peas”. For the potential similarities with high-redshift galaxies and impact on the reionization of the universe, we study the green pea Lyα spectra, which are mostly double-peaked, unlike in any other galaxy sample. If the double peaks are a result of radiative transfer, they can be a useful source of information on the green pea interstellar medium and ionizing radiation escape.

Methods. We select a sample of twelve archival green peas and we apply numerical radiative transfer models to reproduce the observed Lyα spectral profiles, using the geometry of expanding, homogeneous spherical shells. We use ancillary optical and ultraviolet data to constrain the model parameters, and we evaluate the match between the models and the observed Lyα spectra. As a second step, we allow all the fitting parameters to be free, and examine the agreement between the interstellar medium parameters derived from the models and those from ancillary data.

Results. The peculiar green pea double-peaked Lyα line profiles are not correctly reproduced by the constrained shell models. Conversely, unconstrained models fit the spectra, but parameters derived from the best-fitting models are not in agreement with the ancillary data. In particular: 1) the best-fit systemic redshifts are larger by 10–250 km s−1 than those derived from optical emission lines; 2) the double-peaked Lyα profiles are best reproduced with low-velocity (≲150 km s−1) outflows that contradict the observed ultraviolet absorption lines of low-ionization-state elements with characteristic velocities as large as 300 km s−1; and 3) the models need to consider intrinsic Lyα profiles that are on average three times broader than the observed Balmer lines.

Conclusions. Differences between the modelled and observed velocities are larger for targets with prominent Lyα blue peaks. The blue peak position and flux appear to be connected to low column densities of neutral hydrogen, leading to Lyα and Lyman-continuum escape. This is at odds with the kinematic origin of the blue peak in the homogeneous shell models. Additional modelling is needed to explore alternative geometries such as clumpy media and non-recombination Lyα sources to further constrain the role and significance of the Lyα double peaks.
Estimating the equation of state from measurements of neutron star radii with 5% accuracy
Authors: Sieniawska M. , Bejger M. , Haskell B.
Published: May 2018

Context. Observations of heavy (⋍2 M⊙) neutron stars, such as PSR J1614−2230 and PSR J0348+0432, in addition to the recent measurement of tidal deformability from the binary neutron-star merger GW170817, place interesting constraints on theories of dense matter. Currently operating and future observatories, such as the Neutron star Interior Composition Explorer (NICER) and the Advanced Telescope for High ENergy Astrophysics (ATHENA), are expected to collect information on the global parameters of neutron stars, namely masses and radii, with an accuracy of a few percent. Such accuracy will allow for precise comparisons of measurements to models of compact objects and significantly improve our understanding of the physics of dense matter.

Aims. The dense-matter equation of state is still largely unknown. We investigate how the accuracy of measurements expected from the NICER and ATHENA missions will improve our understanding of the dense-matter interior of neutron stars.

Methods. We compared global parameters of stellar configurations obtained using three different equations of state: a reference (SLy4 EOS) and two piecewise polytropes manufactured to produce mass-radius relations indistinguishable from an observational point of view, i.e. within the predicted error of radius measurement. We assumed observational errors on the radius determination corresponding to the accuracies expected for the NICER and ATHENA missions. The effect of rotation was examined using high-precision numerical relativity computations. Because masses and rotational frequencies might be determined very precisely in the most optimistic scenario, only the influence of observational errors on radius measurements was investigated.

Results. We show that ±5% errors in radius measurement lead to ~10% and ~40% accuracy in central parameter estimations for low-mass and high-mass neutron stars, respectively. Global parameters, such as oblateness and surface area, can be established with 8–10% accuracy, even if only compactness (instead of mass and radius) is measured. We also report on the range of tidal deformabilities corresponding to the estimated masses of GW170817 for the assumed uncertainty in radius.
Time-dependent molecular emission in IRC + 10216
Authors: Pardo J. R. , Cernicharo J. , Velilla Prieto L. , Fonfría J. P. , Agúndez M. , Quintana-Lacaci G. , Massalkhi S. , Tercero B. , Gómez-Garrido M. , de Vicente P. , Guélin M. , Kramer C. , Marka C. , Teyssier D. , Neufeld D.
Published: May 2018

Context. The variability in IRC+10216, the envelope of the asymptotic giant branch (AGB) star CW Leo, has attracted increasing attention in recent years. Studying the details of this variability in the molecular emission required a systematic observation program.

Aims. We aim to reveal and characterize the periodical variability of the rotational lines from several molecules and radicals in IRC+10216, and to compare it with previously reported IR variability.

Methods. We carried out systematic monitoring within the ~80–116 GHz frequency range with the IRAM 30 m telescope.

Results. We report on the periodical variability in IRC+10216 of several rotational lines from the following molecules and radicals: HC3N, HC5N, CCH, C4H, C5H, and CN. The analysis of the variable molecular lines provides periods that are consistent with previously reported IR variability, and interesting phase lags are revealed that point toward radiative transfer and pumping, rather than chemical effects.

Conclusions. This study indicates that observations of several lines of a given molecule have to be performed simultaneously or at least at the same phase in order to avoid erroneous interpretation of the data. In particular, merging ALMA data from different epochs may prove to be difficult, as shown by the example of the variability we studied here. Moreover, radiative transfer codes have to incorporate the effect of population variability in the rotational levels in CW Leo.
Molecule mapping of HR8799b using OSIRIS on Keck
Authors: Petit dit de la Roche D. J. M. , Hoeijmakers H. J. , Snellen I. A. G.
Published: May 2018

Context. In 2015, Barman et al. (ApJ, 804, 61) presented detections of absorption from water, carbon monoxide, and methane in the atmosphere of the directly imaged exoplanet HR8799b using integral field spectroscopy (IFS) with OSIRIS on the Keck II telescope. We recently devised a new method to analyse IFU data, called molecule mapping, searching for high-frequency signatures of particular molecules in an IFU data cube.

Aims. The aim of this paper is to use the molecule mapping technique to search for the previously detected spectral signatures in HR8799b using the same data, allowing a comparison of molecule mapping with previous methods.

Methods. The medium-resolution H- and K-band pipeline-reduced archival data were retrieved from the Keck archive facility. Telluric and stellar lines were removed from each spectrum in the data cube, after which the residuals were cross-correlated with model spectra of carbon monoxide, water, and methane.

Results. Both carbon monoxide and water are clearly detected at high signal-to-noise, however, methane is not retrieved.

Conclusions. Molecule mapping works very well on the OSIRIS data of exoplanet HR8799b. However, it is not evident why methane is detected in the original analysis, but not with the molecule mapping technique. Possible causes could be the presence of telluric residuals, different spectral filtering techniques, or the use of different methane models. We do note that in the original analysis methane was only detected in the K-band, while the H-band methane signal could be expected to be comparably strong. More sensitive observations with the JWST will be capable of confirming or disproving the presence of methane in this planet at high confidence.