On-chip non-uniformly spaced multi-channel microwave photonic signal processor based on an ultrahigh-Q multimode micro-disk resonator.

Multi-channel microwave photonic (MWP) signal processing can simultaneously perform different task operations on multiple signals carried by multiple wavelengths, which holds great potential for ultrafast signal processing and characterization in a wavelength-division-multiplexed (WDM) network. As emerging telecommunication services create more data, an elastic optical network, which has a flexible and non-uniform spectrum channel spacing, is an alternative architecture to meet the ever-increasing data transfer need. Here, for the multi-channel ultra-fast signal processing in the elastic optical network, we propose and demonstrate an on-chip non-uniformly spaced multi-channel microwave photonic signal processor based on an ultrahigh-Q multimode micro-disk resonator (MDR). In the proposed signal processor, an MDR supporting multiple different order whispering-gallery modes (WGMs) with an ultrahigh Q-factor is specifically designed. Benefiting from the large and different free spectral ranges (FSRs) provided by the different order WGMs, a non-uniformly spaced multi-channel microwave photonic signal processor is realized, and various processing functions are experimentally demonstrated including bandpass filtering with a narrow passband of 103 MHz, a rejection ratio of 22.3 dB and a frequency tuning range from 1 to 30 GHz, multiple frequency measurement with a frequency measurement range from 1 to 30 GHz, a frequency resolution better than 200 MHz and a measurement accuracy of 91.3 MHz, and phase shifting with a phase tuning range from -170°âˆ¼160°, an operational bandwidth of 26 GHz from 6 GHz to 32 GHz and a small power variation of 0.43 dB. Thanks to the coexistence of different order WGMs supported by the MDR, non-uniformly spaced multi-channel signal processing is enabled with the key advantages including a broad operation bandwidth, an ultra-narrow frequency selectivity, and a large phase tuning range with a small power variation. The proposed signal processor is promising to be widely used in future elastic optical networks with flexible spectrum grids.

Design and optimization of a passive PT-symmetric grating with asymmetric reflection and diffraction.

In recent years, notions drawn from non-Hermitian physics and parity-time (PT) symmetry have raised considerable attention in photonics, enabling various novel structures with entirely new and unexpected features. Here we propose, design, and optimize a compact passive PT-symmetric grating to achieve asymmetric reflection and diffraction based on a silicon-on-insulator (SOI) platform. The structure is composed of two sets of interleaved tailored gratings, which are all well-defined on the top of a silicon waveguide. Without additional loss or gain materials, the effective index and the scattering loss of the waveguide mode are modulated by the structure design. To our knowledge, it is the first time that the scattering loss arising from grating elements is regarded as an efficient way to realize PT-symmetric structure. The complicated multi-parameter optimization process of the proposed PT-symmetric grating is completed by using the particle swarm optimization (PSO) algorithm. In the simulation, asymmetric reflection with high contrast ratio is realized. We also find that the waveguide-to-free-space diffraction from one side of the structure is significantly suppressed, leading to asymmetric diffraction. Moreover, we investigate the fabrication tolerance of the proposed PT-symmetric grating. Our work provides a new perspective for exploring and creating complicated on-chip PT-symmetric devices.

Farming experience and farmers' adoption of low-carbon management practices: the case of soil testing and fertilizer recommendations in China.

In response to global climate change, the Chinese Government has taken numerous measures to promote low-carbon management practices, but the overall adoption rate has been lower than expected. Empirical studies on the path dependence of farming experience, that is, long-standing planting concepts that will hinder farmers from adopting new technologies, have not been reported. Hence, to fill the research gaps, this paper uses survey data from 805 rice farmers in Zhejiang, Hubei, and Jiangxi provinces, China, to examine the impact of farming experience on the adoption of soil testing and fertilizer recommendations. The results show that farming experience significantly negatively affects the adoption of low-carbon practices, especially among farmers with low resource endowment. However, farmers, who make decisions based jointly on farming experience and social networks, are more likely to adopt low-carbon practices. This means that as long as farming experience is used reasonably, for example, by broadening the social network of farmers and urging them to form a decision-making method that comprehensively utilizes farming experience and social networks, it can also demonstrate value. Our findings contribute meaningfully to the development of efforts to promote the adoption of low-carbon management practices in China.

How Do Different Types of Entrepreneurial Networks and Decision-Making Influence the Identification of Entrepreneurial Opportunities?

Entrepreneurial networks are important for the identification of entrepreneurial opportunities and development in the context of social media. This exploratory research investigates the relationships in entrepreneurial networks, by considering decision-making, and entrepreneurial opportunities, and focusing on the role of decision-making in the relationship between entrepreneurial networks and entrepreneurial opportunities. Using data from 512 Chinese entrepreneurial firms, hierarchical regression analyses and structural equation modeling are employed to create a mediation model that links entrepreneurial networks to entrepreneurial opportunities through decision-making. Our findings are as follows: (1) heterogeneous networks are positively related to innovative opportunities, and homogeneous networks are positively related to imitative opportunities; (2) heterogeneous networks positively affect non-linear decision-making (non-linear DM) while homogeneous networks positively influence linear decision-making (linear DM); (3) positive relationships exist between non-linear DM and innovative opportunities and between linear DM and imitative opportunities; and (4) non-linear DM fully mediates between heterogeneous networks and innovative opportunities, and linear DM partially mediates between homogeneous networks and imitative opportunities. This paper contributes to literature on entrepreneurship by broadening understanding of the mechanisms of entrepreneurial opportunity formation in emerging markets and provides important insights for entrepreneurs and policymakers.

The power of habit: does production experience lead to pesticide overuse?

The influence of farmers' production experience on pesticide overuse is empirically analyzed by an endogenous switching probit model of pesticide use time, type, and dosage, based on survey data of 836 rice farmers in the Yangtze River Basin of China. We find that farmers' production experience is an important cause of pesticide overuse, especially for small-scale farmers. Older, self-sufficient, small-scale, non-cooperative members and rice farmers with distant market towns are more likely to use pesticides based on their personal experience. In terms of pesticide use time, type, and dosage, 35.26%, 30.10%, and 28.52% of the samples, respectively, relied on a decision based on "experience." Among them, farmers' decision-making based on production experience for pesticide type and dosage are the key causes of pesticide overuse. These results will be helpful for reducing pesticides and correcting farmers' "bad habits" within agricultural ecosystems.

[Experience Using Oncology Nurse Navigation to Help the Psychological Adjustment of an Outpatient With Rare Tumor Recurrence].

Oncology Nurse Navigation is a professional service that integrates complex medical care procedures and promotes patient awareness of the major nursing problems. Using pre-assessment strategies and the integration of medical care information, Nurse Navigators help patients and their families gain comprehensive medical information and nursing care guidance from their initial post-diagnosis visit to their follow-up visits after remission. This article describes the author's experience with a 53-year-old married overseas Chinese woman who had been diagnosed with a rare tumor, PEComa, and who had traveled to Taiwan for treatment. During the outpatient care period with tumor progression, in addition to disease-related psychological and physical discomfort and pain, the prolonged uncertainty regarding treatment had induced adjustment difficulties and psychological symptoms in the patient. The patient's husband continued to work at his job in order to support the family's finances and was not able to maintain a close understanding of his wife's situation. He developed emotional stress when he saw his wife's disease relapse. The authors used Oncology Nurse Navigation approaches to actively assess the needs of the patient and her spouse, to explore their psychological state using emotional assessment scales, to understand the impact of recurrence on the family, to provide available resources and information, to help the couple learn to cope with psychological adjustment symptoms, to enhance their cognitive understanding of the disease, and to learn useful measures that helped them regain physical control, control over the treatment process, and effectively adapt to the disease and its effects. The authors' experience using Oncology Nurse Navigation with this patient may serve as a reference for healthcare professionals to facilitate the proactive assessment of patient needs at different stages of outpatient care, to remove barriers to seeking medical care through early interventions, and to implement a comprehensive and patient-centered approach to cancer treatment that may improve cancer treatment efficacy and quality of care.

Effects of ovarian fluid, venom and egg surface characteristics of Tetrastichus brontispae (Hymenoptera: Eulophidae) on the immune response of Octodonta nipae (Coleoptera: Chrysomelidae).

Although the importance of parasitoids as biocontrol agents has long been recognized, systematic studies of the physiological mechanisms are scarce, especially in those parasitoids that are able to successfully invade their hosts by activating host immune responses. This study explored this phenomenon by investigating the effects of ovarian fluid, venom and egg surface characteristics of Tetrastichus brontispae (Hymenoptera: Eulophidae) on host immunity. The results showed that the injection of venom alone induced higher phenoloxidase activity, while a mixture of ovarian plus venom fluids provoked higher granulocyte and plasmatocyte spreading ratios, highlighting the role that egg surface characteristics may play in successful parasitism. After thorough investigation, the presence of a hemomucin homologue was documented on the egg surface (which was named Tetrastichus brontispae adipocyte plasma membrane associated protein-like, TbAPMAP-like), while the absence of polydnaviruses, fibrous layers and virus-like filaments was confirmed. The higher encapsulation index of eggs incubated with TbAPMAP-like polyclonal antibody demonstrated the protection of the protein against encapsulation. These results contribute to our understanding of the mechanisms used by endoparasitoids to evade encapsulation during the early parasitism stage while enriching our knowledge of local active regulatory mechanisms. It is likely that this is the first study to determine the egg protective properties of TbAPMAP-like in host-parasite systems.

Pd-P nanoparticles supported on PxOy-incorporated carbon nanotubes for enhanced methanol oxidation in an alkaline medium.

Phosphorous oxide (PxOy)-incorporated carbon nanotubes (PCNTs) and nitric acid treated carbon nanotubes (OCNTs) are first synthesized, then phosphorous modified palladium nanoparticles (Pd-P NPs) supported on PCNTs (Pd-P/PCNTs) and OCNTs (Pd-P/OCNTs) are synthesized and employed as electrocatalysts in a methanol oxidation reaction. Pd-P/PCNTs show enhanced electrocatalytic activity and stability in comparison to Pd-P/OCNTs. Combining surface analysis and electrochemical performance, PxOy incorporated into CNTs could create anchoring sites for Pd ions and P precursors, which could facilitate the synthesis of Pd-P NPs in an aqueous solution containing Pd ions and sodium hypophosphite serving as a reducing agent and a P source. The electronic modification of embedded Pd-P NPs on PxOy-incorporated CNTs accounts for the enhanced electrochemical performance of Pd-P/PCNTs.

Nanosized Pd-Au bimetallic phases on carbon nanotubes for selective phenylacetylene hydrogenation.

Palladium (Pd)-catalyzed selective hydrogenation of alkynes has been one of the most studied hydrogenation reactions in the last century. However, kinetic studies conducted to reveal the catalyst's active centers have been hindered because of dynamic surface changes on Pd during the reaction. In the present study, bimetallic Pd-Au nanoparticles supported on carbon nanotubes have been synthesized at room temperature as catalysts for selective hydrogenation of phenylacetylene, which show effectively enhanced selectivity compared to their monometallic counterparts. Structural and surface analyses of fresh and reacted catalysts reveal that selective hydrogenation of phenylacetylene is favored over nanosized Pd-Au bimetallic phases due to modifications in the Pd surface in terms of neighboring site isolation and electron density reduction.