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Convolutional neural networks (CNNs) lack robustness to test image corruptions that are not seen during training. In this paper, we propose a new layer for CNNs that increases their robustness to several types of corruptions of the input images. We call it a ‘push–pull’ layer and compute its response as the combination of two half-wave rectified convolutions, with kernels of different size and opposite polarity. Its implementation is based on a biologically motivated model of certain neurons in the visual system that exhibit response suppression, known as push–pull inhibition. We validate our method by replacing the first convolutional layer of the LeNet, ResNet and DenseNet architectures with our push–pull layer. We train the networks on original training images from the MNIST and CIFAR data sets and test them on images with several corruptions, of different types and severities, that are unseen by the training process. We experiment with various configurations of the ResNet and DenseNet models on a benchmark test set with typical image corruptions constructed on the CIFAR test images. We demonstrate that our push–pull layer contributes to a considerable improvement in robustness of classification of corrupted images, while maintaining state-of-the-art performance on the original image classification task. We released the code and trained models at the url http://github.com/nicstrisc/Push-Pull-CNN-layer.

Enediamines was prepared by simple reaction of arylazomalononitriles with piperidine or morphilines in high yield. Reaction of the obtained enediamines with acid and hydrazines was studied. Structure of the novel enediamines was established by X-ray data as well as, spectroscopic and analytical data.

Azoheteroarenes are the most recent derivatives targeted to further improve the properties of azo‐based photoswitches. Their light‐induced mechanism for trans–cis isomerization is assumed to be very similar to that of the parent azobenzene. As such, they inherited the controversy about the dominant isomerization pathway (rotation vs. inversion) depending on the excited state (nπ* vs. ππ*). Although the controversy seems settled in azobenzene, the extent to which the same conclusions apply to the more structurally diverse family of azoheteroarenes is unclear. Here, by means of non‐adiabatic molecular dynamics, the photoisomerization mechanism of three prototypical phenyl‐azoheteroarenes with increasing push–pull character is unraveled. The evolution of the rotational and inversion conical intersection energies, the preferred pathway, and the associated kinetics upon both nπ* and ππ* excitations can be linked directly with the push–pull substitution effects. Overall, the working conditions of this family of azo‐dyes is clarified and a possibility to exploit push–pull substituents to tune their photoisomerization mechanism is identified, with potential impact on their quantum yield., At a push: Azoheteroarene derivatives with increased push–pull character have been investigated computationally, revealing how the push–pull substitution affects the rotation and inversion conical intersection energies, the preferred pathway, and the associated kinetics upon both nπ* and ππ* excitations.

Planetary exploration rovers have required a high traveling performance to overcome obstacles such as loose soil and rocks. Push-pull locomotion rovers is a unique scheme, like an inchworm, and it has high traveling performance on loose soil. Push-pull locomotion uses the resistance force by keeping a locked-wheel related to the ground, whereas the conventional rotational traveling uses the shear force from loose soil. The locked-wheel is a key factor for traveling in the push-pull scheme. Understanding the sinking behavior and its resistance force is useful information for estimating the rover’s performance. Previous studies have reported the soil motion under the locked-wheel, the traction, and the traveling behavior of the rover. These studies were, however, limited to the investigation of the resistance force and amount of sinkage for the particular condition depending on the rover. Additionally, the locked-wheel sinks into the soil until it obtains the required force for supporting the other wheels’ motion. How the amount of sinkage and resistance forces are generated at different wheel sizes and mass of an individual wheel has remained unclear, and its estimation method hasn’t existed. This study, therefore, addresses the relationship between the sinkage and its resistance force, and we analyze and consider this relationship via the towing experiment and theoretical consideration. The results revealed that the sinkage reached a steady-state value and depended on the contact area and mass of each wheel, and the maximum resistance force also depends on this sinkage. Additionally, the estimation model did not capture the same trend as the experimental results when the wheel width changed, whereas, the model captured a relatively the same trend as the experimental result when the wheel mass and diameter changed.

International audience; This article gathers, as of 2020, examples of (hetero)dinuclear dinitrogen complexes that are formed by Lewis acid (LA)–base interaction thanks to dative bonding between an electron‐deficient s‐, p‐, or d‐block species and the electron‐rich terminal nitrogen of a neutral end‐on dinitrogen complex. LA coordination to the dinitrogen ligand results in a higher level of activation (i.e. polarization) according to a push–pull mechanism: electron depletion induced by LA coordination amplifies electron back‐donation. The magnitude of such phenomenon will depend on various factors that will be highlighted here, as well as the mean to measure it. In some instances, key reactivities that LA coordination has lent to the dinitrogen complex, or how their combination has allowed the discovery of original reactions will be discussed. This article is organized in three main sections according to which block of the periodic system the LA component of the complexes discussed belongs to. In a final section, pieces of work issued from main group chemistry and relevant in the context of N2 push–pull activation will be presented.

Contour detection is a salient operation in many computer vision applications as it extracts features that are important for distinguishing objects in scenes. It is believed to be a primary role of simple cells in visual cortex of the mammalian brain. Many of such cells receive push-pull inhibition or surround suppression. We propose a computational model that exhibits a combination of these two phenomena. It is based on two existing models, which have been proven to be very effective for contour detection. In particular, we introduce a brain-inspired contour operator that combines push-pull and surround inhibition. It turns out that this combination results in a more effective contour detector, which suppresses texture while keeping the strongest responses to lines and edges, when compared to existing models. The proposed model consists of a Combination of Receptive Field (or CORF) model with push-pull inhibition, extended with surround suppression. We demonstrate the effectiveness of the proposed approach on the RuG and Berkeley benchmark data sets of 40 and 500 images, respectively. The proposed push-pull CORF operator with surround suppression outperforms the one without suppression with high statistical significance.

This paper proposes a push-pull airflow combined with a top draft hood to conduct local exhaust in a rubber workshop. Field measurements are carried out to investigate the characteristics of the emission source, while numerical simulation is performed based on the measurement to test the capture efficiency and to further optimize various parameters including push velocity, hood height and exhaust air rate. Compared with the high-hanging hood, the low-hanging hood can effectively capture the pollutant generated by tyre with lower exhaust air rate. The capture efficiency of the low-hanging hood reaches 98.18% with exhaust air rate of 6000 m3/h and push air velocity of 5m/s. The results indicates that the new ventilation appliance can effectively collect the pollutant at a relatively low exhaust rate.

The recent advancements in Radio frequency (RF) are brought forward using Micro-machining technology, for being small sized and better performances. There is more scope of improvement as it was most recent field of interdisciplinary field. Among the phase shifters using the MEMS technology are growing its importance when compared conventional shifters by overcoming most of the limitations. But switching speed is always a concernwhen a mechanical actuating element is present that compromises the overall performance of the devices. As DMTL base Shifter most rely on the RF MEMS switches, the speed of switch is governing to overall performance of the phase shifter. In this paper push pull base RF MEMS switch was mechanical altered with triangular cantilevers to improve switching speed. This would find better applications in Reconfigurable DMTL’s that operated at wide band applications. The resonant frequency improvement was carried where 13% of switchingwas improvement for the device.

Purpose The purpose of this paper is to review motivational factors driving migration return by assessing both push and pull factors that influence return intentions. The study aims to expand current literature of migration return, and proposes a conceptual framework. Design/methodology/approach A systematic literature review was conducted to determine the push–pull factors that influence international return migration. The authors did a comprehensive search of electronic databases using relevant key terms. Findings The findings highlight motivational factors in detail and classify them into three categories: economic, psychological and situational. Most of the literature concerning motives of migration return discussed economic and psychological as the two major factors, but here other motivational factors are presented, which are named as situational factors in this study. Research limitations/implications The paper adopts a systematic literature review method to probe into existing literature, inevitably lacking some empirical studies; thus, the results may not be generalizable. Therefore, future research is suggested to test the proposed propositions. Practical implications The paper offers compelling propositions, which could be a useful reference for migrants’ repatriation motives. It will shed light on motivational factors beyond economic and physiological factors. Originality/value To the best of the authors’ knowledge, this study is the first to provide a comprehensive review of motivational factors of migration return using push–pull theory and propose beyond psychological and economic factors.

Background Hand-rim wheelchair propulsion is straining and mechanically inefficient, often leading to upper limb complaints. Previous push–pull lever propulsion mechanisms have shown to perform better or equal in efficiency and physiological strain. Propulsion biomechanics have not been evaluated thus far. A novel push–pull central-lever propulsion mechanism is compared to conventional hand-rim wheelchair propulsion, using both physiological and biomechanical outcomes under low-intensity steady-state conditions on a motor driven treadmill. Methods In this 5 day (distributed over a maximum of 21 days) between-group experiment, 30 able-bodied novices performed 60 min (5 × 3 × 4 min) of practice in either the push–pull central lever wheelchair (n = 15) or the hand-rim wheelchair (n = 15). At the first and final sessions cardiopulmonary strain, propulsion kinematics and force production were determined in both instrumented propulsion mechanisms. Repeated measures ANOVA evaluated between (propulsion mechanism type), within (over practice) and interaction effects. Results Over practice, both groups significantly improved on all outcome measures. After practice the peak forces during the push and pull phase of lever propulsion were considerably lower compared to those in the handrim push phase (42 ± 10 & 46 ± 10 vs 63 ± 21N). Concomitantly, energy expenditure was found to be lower as well (263 ± 45 vs 298 ± 59W), on the other hand gross mechanical efficiency (6.4 ± 1.5 vs 5.9 ± 1.3%), heart-rate (97 ± 10 vs 98 ± 10 bpm) and perceived exertion (9 ± 2 vs 10 ± 1) were not significantly different between modes. Conclusion The current study shows the potential benefits of the newly designed push–pull central-lever propulsion mechanism over regular hand rim wheelchair propulsion. The much lower forces and energy expenditure might help to reduce the strain on the upper extremities and thus prevent the development of overuse injury. This proof of concept in a controlled laboratory experiment warrants continued experimental research in wheelchair-users during daily life.

Conducting polymer synthesis of a new benzobisoxazole/thiophene derivative is reported. The conjugated co-polymer presents the lowest bandgap (1.78¿eV) reported for a neutral benzobisoxazole/thiophene polymer. Electrochemical polymerization is carried out by cyclic voltammetry, and the new conducting polymer is characterized by Raman spectroscopy and X-ray photoelectron spectroscopy. The results indicate that the coupling of the monomer unit occurs at the 2,2' positions of the thiophene ring. Theoretical studies in derivatives of this family of compounds are conducted to validate the effect on the bandgap modulation due to the change in the substituent on the phenyl moiety of the monomer. The comparison between experimental and theoretical properties shows the substituents impact on the optical properties of the system, and its viability to be used in sensors.

The development of highly durable, stretchable, and steady triboelectric nanogenerators (TENGs) is highly desirable to satisfy the tight requirement of energy demand. Here, we presented a novel integrated polymeric membrane that is designed by PEDOT:PSSa-naphthalene sulfonated polyimide (PPNSP)-EMI. BF4 Electronic skin (e-skin) for potential TENG applications. The proposed TENG e-skin is fabricated by an interconnected architecture with push-pull 3D ionic electrets that can threshold the transfer of charges through an ion-hopping mechanism for the generation of a higher output voltage (Voc) and currents (Jsc) against an electronegative PTFE film. PPNSP was synthesized from the condensation of naphthalene-tetracarboxylic dianhydride, 2, 2’-benzidine sulfonic acid, and 4,4’diaminodiphenyl ether through an addition copolymerization protocol, and PEDOT:PSSa was subsequently deposited using the dip-coating method. Porous networked PPNSP e-skin with continuous ion transport nano-channels is synthesized by introducing simple and strong molecular push-pull 3D interactions via intrinsic ions. In addition, EMI. BF4 ionic liquid (IL) is doped inside the PPNSP skin to interexchange ions to enhance the potential window for higher output Voc and Iscs. In this article, we investigated the push-pull dynamic interactions between PPNSP-EMI.BF4 e-skin and PTFE and tolerable output performance. The novel PPNSP- EMI.BF4 e-skin TENG produced upto 49.1 V and 1.03 µA at 1 Hz, 74 V and 1.45 µA at 2 Hz, 122.3 V and 2.21 µA at 3 Hz and 171 V and 3.6 µA at 4 Hz, and 195 V and 4.43 µA at 5 Hz, respectively. The proposed novel TENG device was shown to be highly flexible, highly durable, commercially viable, and a prospective candidate to produce higher electrical charge outputs at various applied frequencies.

N-substituted acridine-containing 1,2-dioxetanes have been recently proposed as thermochemiluminescence (TCL) universal labels for bioanalytical applications. The TCL properties of these compounds markedly depend on the nature of substituents of the acridine ring. In the attempt to obtain new TCL probes with improved properties and stability, the push-pull approach was adopted, in which both electron withdrawing and electron donating groups are present in the acridine moiety. The results have been useful to better understand the role of the different decorations at the acridine fluorophore in modulating the photophysical properties and the activation parameters of 1,2-dioxetane labels. Moreover, the great versatility and innovation of these molecules make them extremely attractive for bioanalytical applications, in particular as labels for immune- and gene-probe assays.

In this study, we designed a structural model to determine the relationships among push–pull factors, institutional situations, and satisfaction during the COVID-19 pandemic. The 17 selected indicators fell under five domains, namely push factors, pull factors, institutional leadership, international strategies, and satisfaction. Structural equation modeling (SEM) was used to verify the assumptions of the model. Based on 1005 degree-seeking international students’ views, this study found that push and pull factors may coincidentally exist, and their functions can be modified by institutional situations. The findings suggested pull factors will, through institutional leadership, impact students’ satisfaction, while push factors will not. Moreover, the detection of institutional mediation can provide useful information for specific institutes to develop their future recruiting or retaining strategies. These findings enriched our knowledge of the field for higher education sustainable development. For future studies, this design may be useful to interpret the phenomena of global student mobility in higher education settings.

In this study, a new three-phase current-fed push–pull DC–DC converter with high-gain capability was proposed. The proposed circuit has the advantages of three-phase converters and the push–pull converter circuit, with small volume and a simplified gate drive circuit with switches connected to the same reference. The converter was analysed for operation in continuous and discontinuous conduction modes. The analysis includes a description of the topological stage, theoretical waveforms, deduction of the voltage gains and the expressions for its practical design. To validate the theoretical analysis, a 700 W prototype was built and tested with an input voltage of 40 V, an output voltage of 400 V and a switching frequency of 40 kHz. Despite using a unity transformer turns ratio, the prototype had an experimental gain of ∼10, which makes the proposed converter suitable for applications as renewable energy sources systems.

A robust lipophilic dye, based on the structures of the benzothiadiazole heterocycle, was shown to be a potent fluorescent stain for the selective imaging of lipid droplets (LDs) within both live and fixed human cells. Its small molecular framework, large Stokes shift, and vastly improved photostability over that of the current status quo, Nile Red, highlight its tremendous potential as a versatile chemical tool for facilitating LD imaging and research.

In recent years, the number of Chinese students studying abroad continues to grow, with their destination countries becoming diverse. The outbreak of COVID 19 pandemic in 2020 has exerted profound impacts on their decisions of overseas study. Taking a double first-class university in Shanghai as an example, this study explored the decision-making of Chinese undergraduate students who intend to study abroad and the contributing factors that affect their decision-making from the perspective of the push-pull theory. Recommendations were provided for their future choices on overseas study.

Two push–pull derivatives based on a N,N-bis(4-biphenylyl)aniline (BPA) donor block connected to a dicyanovinyl accepting moiety by thienyl and bithienyl π-conjugated spacers have been synthesized and characterized. All-small-molecule planar-heterojunction organic solar cells show promising power conversion efficiencies and impressive fill factor (>73%) correlated with the high hole-mobility induced by the BPA moiety.

The article discusses the implementation of a differential pushpull measurement method using a phase interpolator and a phase meter in an acousto-optical (AO) heterodyne laser interferometer of displacements (in future –a laser interferometer). To reduce the noise level in the measuring signal, a phase locked loop system with a small jitter has been introduced. In the first measure at the beginning of the object’s movement due to the high accuracy of the phase meter, so-called «slow precise» measurements with high resolution, up to ≈λ/10000, where λ is the wavelength of the laser radiation. For high-speed object motion the clock of «fast rough» measurements is used when the high-speed phase interpolator is running and the phase meter is locked. This push-pull principle of operation of the laser interferometer improves the dynamic and metrological parameters of object motion measurements.

Adoption studies have identified gender as one of the factors that determine technology uptake and this has been linked to women’s access to farming information or lack of it. Technology scaling up systems should utilise pathways that are compatible with the needs of rural women, who have to juggle farming with other household chores. Unfortunately, there has been limited effort to evaluate the suitability of the information pathways used to specific gender. The current study evaluates the appropriateness of field days with respect to gender of the participants. Data were collected from selected farmers who attended field days in Kenya, Uganda and Tanzania in 2014. A total of 2 615 participants were interviewed out of 6 221 who attended field days. Descriptive analysis and ordered probit and logit models were used for analysis. The majority of the participants in Kenya and Tanzania were women (51.3% and 62.6%, respectively), whereas in Uganda the majority of participants were men (57.4%). Most participants were middle aged (42 years for women and 45 years for men). The majority of the women (54.1%) had primary level education, with only 29.1% having secondary education, whereas 41% and 40.1% of men had attained primary and secondary education, respectively. The results from the econometric models shows that gender, age, education, being push-pull farmers, perceptions on Striga severity were the main significant determinants of knowledge for the ordered probit. Conversely, gender of the participant, perception on stemborers and Striga weed severity and having mobile phones were the significant determinants of willingness to adopt. The two models were significant at 1% (p

In this work, the structure–property relationship was investigated for a series of Re(I) carbonyls [ReCl(CO)3(R-terpy-κ2N)], [ReCl(CO)3(R-dtpy-κ2N)], and [ReCl(CO)3(R-dppy-κ2N)]. The studied compou...

OBJECTIVE Drug-resistant focal epilepsy is widely recognized as a network disease in which epileptic seizure propagation is likely coordinated by different neuronal oscillations such as low-frequency activity (LFA), high-frequency activity (HFA), or low-to-high cross-frequency coupling. However, the mechanism by which different oscillatory networks constrain the propagation of focal seizures remains unclear. METHODS We studied focal epilepsy patients with invasive electrocorticography (ECoG) recordings and compared multilayer directional network interactions between focal seizures either with or without secondary generalization. Within-frequency and cross-frequency directional connectivity were estimated by an adaptive directed transfer function and cross-frequency directionality, respectively. RESULTS In the within-frequency epileptic network, we found that the seizure onset zone (SOZ) always sent stronger information flow to the surrounding regions, and secondary generalization was accompanied by weaker information flow in the LFA from the surrounding regions to SOZ. In the cross-frequency epileptic network, secondary generalization was associated with either decreased information flow from surrounding regions' HFA to SOZ's LFA or increased information flow from SOZ's LFA to surrounding regions' HFA. INTERPRETATION Our results suggest that the secondary generalization of focal seizures is regulated by numerous within- and cross-frequency push-pull dynamics, potentially reflecting impaired excitation-inhibition interactions of the epileptic network. ANN NEUROL 2019;86:683-694.

Planarizable push–pull probes have been introduced to demonstrate physical forces in biology. However, the donors and acceptors needed to polarize mechanically planarized probes are incompatible with their twisted resting state. The objective of this study was to overcome this “flipper dilemma” with chalcogen‐bonding cascade switches that turn on donors and acceptors only in response to mechanical planarization of the probe. This concept is explored by molecular dynamics simulations as well as chemical double‐mutant cycle analysis. Cascade switched flipper probes turn out to excel with chemical stability, red shifts adding up to high significance, and focused mechanosensitivity. Most important, however, is the introduction of a new, general and fundamental concept that operates with non‐trivial supramolecular chemistry, solves an important practical problem and opens a wide chemical space.

A bandpass push–pull high power amplifier (PA) based on substrate integrated waveguide (SIW) filtering balun power divider is proposed in this article. The filtering characteristic of the PA is realized by the complementary split rings resonators (CSRRs) defected in the balun based on the SIW. Inherent to the middle metal plane of the SIW balun, the 180° phase difference power division can be achieved. Due to the natural differential characteristic of the balun, the proposed design can produce second-harmonic suppression. Greater output power is obtained owing to the filtering balun power combiner. For the fabricated bandpass push–pull PA, it exhibits high-selectivity bandpass response and good PA performance with the peak power-added efficiency (PAE) of 48.7% at 38.5-dBm output power.

A series of perylene-based donor–acceptor–donor (D–A–D) compounds, 3,9-bis(p-(R)-diphenylamino)perylene (R: CN (2a), F (2b), H (2c), Me (2d), and OMe (2e)), was synthesized using 3,9-dibromoperylen...

The synthesis and crystal structures of 1,3-diethyl-5-{(2E,4E)-6-[(E)-1,3,3-tri­methyl­indolin-2-yl­idene]hexa-2,4-dien-1-yl­idene}pyrimidine-2,4,6(1H,3H,5H)-trione or TMI, C25H29N3O3, and 1,3-diethyl-2-sulfanyl­idene-5-[2-(1,3,3-tri­methyl­indolin-2-yl­idene)ethyl­idene]di­hydro­pyrimidine-4,6(1H,5H)-dione or DTB, C21H25N3O2S, are described. These compounds contain the same indole derivative donor group and differ in their acceptor groups (in TMI it contains oxygen in the para position, and in DTB sulfur) and the length of the π-bridge., Two compounds, 1,3-diethyl-5-{(2E,4E)-6-[(E)-1,3,3-tri­methyl­indolin-2-yl­idene]hexa-2,4-dien-1-yl­idene}pyrimidine-2,4,6(1H,3H,5H)-trione or TMI, C25H29N3O3, and 1,3-diethyl-2-sulfanyl­idene-5-[2-(1,3,3-tri­methyl­indolin-2-yl­idene)ethyl­idene]di­hydro­pyrimidine-4,6(1H,5H)-dione or DTB, C21H25N3O2S, have been crystallized and studied. These compounds contain the same indole derivative donor group and differ in their acceptor groups (in TMI it contains oxygen in the para position, and in DTB sulfur) and the length of the π-bridge. In both materials, mol­ecules are packed in a herringbone manner with differences in the twist and fold angles. In both structures, the mol­ecules are connected by weak C—H⋯O and/or C—H⋯S bonds.

This study proposes the use of push‐pull‐mooring model to investigate the main factors behind farmers' willingness to withdraw from rural homesteads with unique survey datasets taken from a pilot area in China. Our empirical results, which were derived from partial least squares structural equation modelling, mostly support our theoretical hypotheses, suggesting that policy cognition is a meaningful moderating factor that reflects farmers' individual attitudes, environmental influences, and social norms and plays a significant role in farmers' decision‐making processes. Our findings have strong policy implications for developing a “strategy of rural vitalization” and reforming the current rural homesteads system in China. Este estudio propone el uso de un modelo de empuje‐atraccion‐enganche para investigar los principales factores que explican la voluntad de los agricultores de abandonar las granjas rurales, a partir de conjuntos de datos de encuestas unicas realizadas en un area piloto en China. Los resultados empiricos, derivados de un modelo de ecuaciones estructurales de minimos cuadrados parciales, apoyan en su mayoria las hipotesis teoricas del articulo, lo que sugiere que la cognicion politica es un factor moderador significativo que refleja las actitudes individuales de los agricultores, las influencias ambientales y las normas sociales, y que desempena un papel significativo en los procesos de decision de los agricultores. Los hallazgos tienen fuertes implicaciones politicas para el desarrollo de una “estrategia de revitalizacion rural” y la reforma del sistema actual de granjas rurales en China. 本稿では、中国のパイロット調査対象地域から得られた独自の調査データセットとPPM (Push‐Pull‐Mooring)モデルを使用して、農村部の集落から退去したいという農家の意向の背景にある主な要因を調べる。この実証研究の結果は、PLS‐SEM (partial least squares structural equation modelling:部分最小二乗共分散構造モデル)を用いて導出したものであるが、我々の仮説を概ね支持するもので、政策の認識は、農家の個々の意見、環境の影響、社会規範を反映し、農家の意思決定の過程において重要な役割を果たす、意義ある調整因子であることを示唆している。本研究の知見には、農村部活性化の政策策定と、現代の中国の農村集落システムを刷新するための強力な政策的インプリケーションがある。

1-(4-Ethynylphenyl)-3,3-dialkyltriaz-1-enes, well-known building blocks for branched dendrimer syntheses, were utilized as a new type of electron-donor component in formal [2 + 2] cycloadditions. The click-type, atom-economic reactions proceed efficiently under ambient conditions without any catalyst. The resulting products are structurally interesting push-pull chromophores and were investigated in the context of optoelectronic properties using UV/Vis spectroscopy, NMR studies, and computational chemistry. (C) 2019 Elsevier Ltd. All rights reserved.

In contemporary organic solar cell (OSC) research, small A-D-A molecules comprising electron donor (D) and acceptor (A) units are increasingly used as a means to control the optoelectronic properties of photovoltaic blends. Slight structural variations to these A-D-A molecules can result in profound changes to the performance of the OSCs. Herein, we study two A-D-A molecules, BTCN-O and BTCN-M, which are identical in structure apart from a subtle difference in the position of alkyl chains, which force the molecules to adopt different equilibrium conformations. These steric effects cause the respective molecules to work better as an electron donor and acceptor when blended with benchmark acceptor and donor materials (PC71BM and PBDB-T). We study the photophysics of these “D:A” blends and devices using a combination of steady-state and time-resolved spectroscopic techniques. Time-resolved photoluminescence reveals the impact of the molecular conformation on the quenching of the A-D-A emission when BTCN-O and BTCN-M are blended with PBDB-T or PC71BM. Ultrafast broadband transient absorption spectroscopy demonstrates that the dynamics of charge separation are essentially identical when comparing BTCN-M and BTCN-O based blends, but the recombination dynamics are quite dissimilar. This suggests that the device performance is ultimately determined by the morphology of the blends imposed by the A-D-A conformation. This notion is supported by X-ray scattering data from the “D:A” films, and electroluminescence data and pump-push-photocurrent spectroscopy on the “D:A” devices. Our findings provide insight into the remarkable structure-function relationship in A-D-A molecules, and emphasize the need for careful morphological and energetic considerations when designing high-performance OSCs.

Urea-functionalized 4-ethynylbenzenes undergo facile formal [2 + 2] cycloaddition followed by retroelectrocyclization upon reaction with tetracyanoethylene, yielding 1,1,4,4-tetracyanobuta-1,3-dienes-based push-pull chromophores. Unlike the

تسعى الدراسة الى معرفة الأشکال والمظاهر لهجرة العمالة اليمنية الوافدة في المجتمع السعودي في مدينة الرياض ، وهدفت الى الکشف عن مدى الحاجة للعمالة اليمنية الوافدة في المجتمع السعودي من خلال معرفة المهن التي يعمل بها العمالة اليمنية والتي لا يعمل بها الشباب السعودي . وما الأشکال والمظاهر لهجرة العمالة اليمنية في الجانب التقني والمهني . کما ناقشت الأشکال والمظاهر لهجرة العمالة اليمنية في جانب المال والأعمال ، وفي الاطار النظري التطور التاريخي للعمالة اليمنية في المجتمع السعودي ، وتم استعرض النظريات المفسرة للدراسة وهي : نظرية الطرد والجذب ، ونظرية رأس المالالاجتماعي وشبکة علاقات المهاجرين ، وتناولت الدراسة عددا من الدراسات السابقة ، التي أهتمت ببعض جوانب الدراسة الحالية ، وفي الاطار المنهجي والذي تم تحديد نوع الدراسة ومنهجها ، وأدوات جمع البيانات ، وعينة الدراسة، أداة الدراسة، مجالات الدراسة ، وبعد ذلک عرض وتحليل بيانات الدراسة ومناقشة نتائجها . واختمت الدراسة عرض لأهم النتائج التي توصلت لها الدراسة والتي من أبرزها أن المجتمع السعودي لا يزال بحاجة الى العمالة اليمنية خاصة في المجالات الخدمية والمهن التي لا تتطلب خبرة ولا تدريب ، ومن النتائج الهامة کذلک رأس المال الاجتماعي والعلاقات القرابية فيما يخص أشکال ومظاهر هجرة العمالة اليمنية حيث أنها تعتمد على العلاقات القرابية بشکل کبير . This study aims at exploring the forms and methods of the immigration of Yemeni workers in the Saudi society in Riyadh, it aimed to investigate the need for the Yemeni workers in the Saudi society through the kind of jobs they do which are abandoned by Saudi youth workers. In addition, what are the forms of immigration in the technical and the vocational field. Furthermore, the study discuss the forms of immigration in the field of business and economy. Moreover, the researcher discusses the theoretical framework of the history of the Yemeni immigration to the Saudi society, and explores the related theories, which are: push pull theory, social capital theory and migrants network relationship, and at the end of the chapter, the study carries the investigation of the previous studies on this matter. In the third chapter, the researcher sets the methodology of the study, collecting data procedure, sample community, researcher instrument and study area. In the fourth chapter, data Analysis and result discussions. In the fifth chapter, presenting the most important result of the study has reached which highlight that the Saudi society is still in need of Yemeni workers especially in the field of service and types of jobs that does not require experience or training, furthermore the study concluded that the social capital is a major influence for the forms and methods of the immigrations, the reason behind that was it depend mainly on relatives, moreover the study concluded more other results can be seen in the fifth chapter. Consequently, the study provided some practical and scientific recommendations on this matter .

Push–pull porphyrins are made of an electron donor (D), an electron acceptor (A), and a conjugated bridge connecting the D and A units. The tunability of their highest occupied molecular orbital (H...

In the present study, some diaminodinitroethylene, (geminal (FOX-7) and cis-DADNE) embedded isomeric structures (C4H2N4O6) are considered. They are consisted of a five or a six-membered ring having DADNE moiety (linked across the amino groups of DADNE) and two exocyclic keto groups. The structures have been subjected to density functional treatment at the levels of B3LYP/6-31G(d,p) and ωB97X-D/6-31G(d,p). Some geometrical, quantum chemical, spectral and thermodynamic properties are obtained and discussed. Also bond dissociation energies for the scission of C-NO2 bonds are calculated at the level of UB3LYP/6-311++G(d,p) and found that the DADNE embedded structures have less stable C-NO2 bond as compared to FOX-7.

Motivations to attend nudist festivals and their association with tourist motivation factors have been largely unexplored. Based on qualitative interviews with nudist tourists, this study e...

International audience; Recent developments in uncertainty quantification show that a full inversion of model parameters is not always necessary to forecast the range of uncertainty of a specific prediction in Earth Sciences. Instead, Bayesian evidential learning (BEL) uses a set of prior models to derive a direct relationship between data and prediction. This recent technique has been mostly demonstrated for synthetic cases. This paper demonstrates the ability of BEL to predict the posterior distribution of temperature in an alluvial aquifer during a cyclic heat tracer push-pull test. The data set corresponds to another push-pull experiment with different characteristics (amplitude, duration, number of cycles). This experiment constitutes the first demonstration of BEL on real data in a hydrogeological context. It should open the range of future applications of the framework for both scientists and practitioners.

Production of maize, Zea mays L. (Poaceae), in sub-Saharan Africa is threatened by a new invasive pest, fall armyworm (FAW), Spodoptera frugiperda (JE Smith) (Lepidoptera: Noctuidae). To mitigate this threat, push-pull companion cropping, a system originally developed for management of lepidopteran stemborers, may be used to control FAW. The original system involved trap crops that functioned as a 'pull' component to attract moths away from the main crop. How grass species can be used as trap crops in a push-pull system to control FAW is a question that remains to be answered, because maize is already a highly preferred host plant. Therefore, we tested oviposition preference of FAW female moths in no-choice and two-choice experiments and larval performance on six selected grasses (Poaceae) to assess their roles as trap crop 'pull' plants in the system. In no-choice tests, numbers of eggs deposited on Brachiaria brizantha (Hochst. ex A. Rich.) R. Webster cv. 'Piata', cv. 'Mulato II', and cv. 'Xaraes', and Napier grass (Pennisetum purpureum K. Schumach) cv. 'South Africa' were not statistically different from those deposited on maize. In two-choice tests between grasses and maize, there were no significant differences in number of eggs laid when the plants were of the same size. However, in two-choice tests with maize plants half of the size of the grasses, significantly more eggs were laid on B. brizantha cv. Xaraes and P. purpureum cv. South Africa than on maize, suggesting that crop phenology could make a difference. Numbers of larvae arrested on grass leaf cuts were considerably lower than those on maize leaf cuts after 48 h. In two-choice tests with maize, molasses grass (Melinis minutiflora P. Beauv.) was the only grass that was significantly preferred to maize for larval settlement after 24 h. After 48 h in the two-choice test, it was the only grass that retained larvae, although the larval count was significantly lower than on maize. Our data show that none of the grasses tested were strongly preferred to maize, but the results indicate plants attractive to FAW adults and larvae that could be utilized in a multiple trap crop approach to target various stages of the pest. Furthermore, results indicate the importance of planting these companion plants earlier than maize.

The advent of fintech is blowing a new wind into the financial industry. New business models have been created and consumers’ access to financial services is higher than ever. Internet-only banks based on advanced information technologies have emerged as a leader in the fintech industry, and these banks are fiercely competing with large banks using internet banking as a weapon to attract new customers. The purpose of this study is to explore the factors that influence customers’ intention to switch to internet-only banking services from traditional internet banking services in Korea. To this end, a research model was developed based on the push-pull-mooring model (PPM), which is a migration theory. The research model was analyzed using partial least squares structural equation modeling (PLS-SEM). The findings will provide the practitioners of the new internet-only bank with strategic guidance for attracting new customers and help practitioners of traditional banks to retain current customers.

Introduction: The combined application of long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) has led to mixed results (Significant reduction vs no impact) on malaria burden. Other studies have attempted to study the combined effects of house screening (HS) and LLINs have demonstrated a reduction in indoor vector densities and malaria when the interventions are combined. In addition to malaria vectored by mosquitoes, farmers living in rural settings face challenges from crop pests, which significantly reduce agricultural productivity and negatively impact their food security. Thus, addressing the coexisting risks of malaria and crop pests could contribute to improved livelihood of communities. Design: A three armed household, cluster-randomized, controlled study will be conducted to assess the impact of HS, LLINs and PPT against clinical malaria in children than LLINs alone in Ethiopia. The unit of randomization will be the household, which include a house and its occupants. A total of 663 households will be enrolled in this study. All the households will receive the LLINs. Then other treatments will be overlaid according to the randomization sequence. Thus, 246 households will receive HS, and 250 households will receive HS and PPT before the commencement of clinical follow-up. The rest 167 houses which received LLINs only will be used as control. One child aged not more than 14 years will be enrolled from each household and followed for clinical malaria using active case detection to estimate malaria incidence for two malaria transmission seasons. Results: Episodes of clinical malaria, the prevalence of anaemia, density of malaria vector mosquitoes, sporozoite infection rate, crop infestation rate due to stem borer and fall army worm, crop yield gain, livestock productivity and cost effectiveness analysis will be the end points of this study. Socio-economic, social demographic, cost-effectiveness analysis will be conducted using qualitative and participatory methods to explore the acceptability of HS and PPT. Conclusion Documenting the combined impact of LLINs, HS and PPT on the prevalence of clinical malaria and crop pest damage will be the first of its kind and will provide deep insight and evidence base for forging collaborations between health and agriculture sectors. Trial Registration: The protocol was registered online on Date 28/05/2020 on sight www.pactr.org With registration No: PACTR202006878245287.

Solvatochromic dyes have emerged as a new class of fluorescent probes in the field of lipid membranes due to their ability to identify the lipid organization of biomembranes in live cells by changing the colour of their fluorescence. This type of solvatochromic function is useful for studying the heterogeneous features of biomembranes caused by the uneven distribution of lipids and cholesterols in live cells and related cellular processes. Therefore, a variety of advanced solvatochromic dyes have been rapidly developed over the last decade. To provide an overview of the works recently developed solvatochromic dyes have enabled, we herein present some solvatochromic dyes, with a particular focus on those based on pyrene and Nile red. As these dyes exhibit preferable photophysical properties in terms of fluorescence microscopy applications and unique distribution/localization in cellular compartments, some have already found applications in cell biological and biophysical studies. The goal of this review is to provide information to researchers who have never used solvatochromic dyes or who have not discovered applications of such dyes in biological studies.

International audience; In this article, a series of three-component photoinitiating systems (PISs) based on push-pull dyes are proposed. The systems are composed of the newly synthesized push-pull dyes and different co-initiators, namely an iodonium salt and a tertiary amine (ethyl dimethylaminobenzoate EDB). Photoinitiation abilities and photochemical properties of the different investigated photoinitiating systems were studied in detail. Notably, the mechanisms related to the polymerization efficiencies were determined using different techniques such as UV-visible absorption and fluorescence spectroscopy. Moreover, the photoinitiation abilities of the threecomponent systems for the sunlight-induced polymerization processes were also 2 examined, indicating that sunlight can act as an effective light source for photopolymerization. Finally, 3D patterns with a spatial resolution were successfully produced by the direct laser writing (DLW) approach, even with photosensitive resins containing silica fillers.