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The design and optimization of laser-Compton x-ray systems based on compact distributed charge accelerator structures can enable micron-scale imaging of disease and the concomitant production of beams of Very High Energy Electrons (VHEEs) capable of producing FLASH-relevant dose rates. The physics of laser-Compton x-ray scattering ensures that the scattered x-rays follow exactly the trajectory of the incident electrons, thus providing a route to image-guided, VHEE FLASH radiotherapy. The keys to a compact architecture capable of producing both laser-Compton x-rays and VHEEs are the use of X-band RF accelerator structures which have been demonstrated to operate with over 100 MeV/m acceleration gradients. The operation of these structures in a distributed charge mode in which each radiofrequency (RF) cycle of the drive RF pulse is filled with a low-charge, high-brightness electron bunch is enabled by the illumination of a high-brightness photogun with a train of UV laser pulses synchronized to the frequency of the underlying accelerator system. The UV pulse trains are created by a patented pulse synthesis approach which utilizes the RF clock of the accelerator to phase and amplitude modulate a narrow band continuous wave (CW) seed laser. In this way it is possible to produce up to 10 μA of average beam current from the accelerator. Such high current from a compact accelerator enables production of sufficient x-rays via laser-Compton scattering for clinical imaging and does so from a machine of "clinical" footprint. At the same time, the production of 1000 or greater individual micro-bunches per RF pulse enables > 10 nC of charge to be produced in a macrobunch of < 100 ns. The design, construction, and test of the 100-MeV class prototype system in Irvine, CA is also presented.

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Deep learning has gained superior accuracy on Euclidean structure data in neural networks. As a result, non-Euclidean structure data, such as graph data, has more sophisticated structural information, which can be applied in neural networks as well to address more complex and practical problems. However, actual graph data obeys a power-law distribution, so the adjacent matrix of a graph is random and sparse. Graph processing accelerator (GPA) is designed to handle the problems above. However, graph computing only processes 1-dimensional data. In graph neural networks (GNNs), graph data is multi-dimensional. Consequently, GNNs include the execution processes of both traditional graph processing and neural network, which have irregular memory access and regular computation, respectively. To obtain more information in graph data and require better model generalization ability, the layers of GNN are deeper, so the overhead of memory access and computation is considerable. At present, GNN accelerators are designed to deal with this issue. In this paper, we conduct a systematic survey regarding the design and implementation of GNN accelerators. Specifically, we review the challenges faced by GNN accelerators, and existing related works in detail to process them. Finally, we evaluate previous works and propose future directions in this booming field. [ABSTRACT FROM AUTHOR]

The prospect of employing nanophotonic methods for controlling photon–electron interactions has ignited substantial interest within the particle accelerator community. Silicon-based integrated dielectric laser acceleration (DLA) has emerged as a viable option by leveraging localized photonic effects to emit, accelerate, and measure electron bunches using exclusively light. Here, using highly regular nanopatterning over large areas while preserving the crystalline structure of silicon is imperative to enhance the efficiency and yield of photon-electron effects. While several established fabrication techniques may be used to produce the required silicon nanostructures, alternative techniques are beneficial to enhance scalability, simplicity and cost-efficiency. In this study, we demonstrate the nano-synthesis of silicon structures over arbitrarily large areas utilizing exclusively deep ultraviolet (DUV) ultrafast laser excitation. This approach delivers highly concentrated electromagnetic energy to the material, thus producing nanostructures with features well beyond the diffraction limit. At the core of our demonstration is the production of silicon laser-induced surface structures with an exceptionally high aspect-ratio -reaching a height of more than 100 nm- for a nanostructure periodicity of 250 nm. This result is attained by exploiting a positive feedback effect on the locally enhanced laser electric field as the surface morphology dynamically emerges, in combination with the material properties at DUV wavelengths. We also observe strong nanopattern hybridization yielding intricate 2D structural features as the onset of amorphization takes place at high laser pulse fluence. This technique offers a simple, yet efficient and attractive approach to produce highly uniform and high aspect ratio silicon nanostructures in the 200–300 nm range.

Purpose: This article summarizes the short lecture on gantries given at the "Hadrontherapy: status and perspectives. Development of a hadrontherapy facility: learning from the existing" event. Methods and materials: An introduction to gantries is given describing what a gantry is and which are the main difficulties and choices for an ion gantry. The gantry design activities ongoing at CNAO are shortly described. Results: The first part of the lecture and of the article describes some of the main choices to be made when designing a carbon ion gantry. The second part of the lecture reports shortly about the activities ongoing at CNAO within the HITRIplus and the EuroSIG projects. Conclusions: Carbon ion gantries are large, complicated and expensive objects and presently only three gantries for carbon are operational worldwide. The design of a gantry can be optimized in many ways and in many respects. In the paper, without the ambition of being exhaustive, some of the main choices are illustrated and the pros and cons of the possible options are discussed. Finally the gantry design activities ongoing in the EuroSIG collaboration and in the HITRIplus project are shortly reported. [ABSTRACT FROM AUTHOR]

Copper possesses better conductivity which makes it an ideal plating choice for the electronics and semiconductor industries. Copper electroless plating can be carried easily on non-conductors like plastics, ceramics, fabrics, glasses etc. One of the limitations of electroless plating is its very low plating rate, which is further reduced by the addition of stabilizers which is quite essential for the plating process. A stabilizer improves stability of bath and deposit qualities, but slows down the plating rate. The current study focuses on the enhancement of plating rate by the addition of accelerators in eco-friendly copper methane sulphonate bath. It is observed that accelerators like guanidine hydrochloride and 2,6-diaminopyridine improves the rate of deposition with good deposit quality. It was studied with weight gain method and analyzed with tafel polarization studies. The surface of the deposit was analyzed with X-ray diffraction (XRD) and scanning electrode microscope (SEM). [ABSTRACT FROM AUTHOR]

Purpose: This paper aims to understand technology-based accelerators' legitimation efforts in an emerging entrepreneurship ecosystem. Design/methodology/approach: This research is based on qualitative inductive methodology using ten Turkish technology-based accelerators. Findings: The analysis indicates that accelerators' legitimation efforts are shaped around crafting a distinctive identity and mobilizing allies around this identity; and establishing new collaborations to enable collective action. Further, the authors observe two types of technology-based accelerators, namely, "deal flow makers" and "welfare stimulators" in Turkey. These variations among accelerators affect how they build their legitimacy. Different types of accelerators make alliances with different actors in the entrepreneurship ecosystem. Accelerators take collective action to build a collective identity and simultaneously imply how they are distinguished from other organizations in the same category and the ones in the old category. Originality/value: This study presents a framework to understand how accelerators use strategies and actions to legitimize themselves as new organizations and advocate new norms, values and routines in an emerging entrepreneurship ecosystem. The framework also highlights how different accelerators support legitimacy building by managing the judgments of diverse audiences and increasing the variety of resources these audiences provide to the ecosystem. [ABSTRACT FROM AUTHOR]

Incubators have been studied extensively in the private sector, such as those that engage in technological innovation or growing small businesses. The scholarship has not sufficiently explored the efforts of incubators in the non-profit sector that help create programs supporting, mentoring, and cultivating social entrepreneurs. There are numerous documented cases of non-profit organisations establishing initiatives that help motivated entrepreneurs achieve social change; but research is lagging in developing a systematic understanding of these effort's impact, and the factors associated with the success of non-profit initiatives that support social entrepreneurs. This paper seeks to understand the nature of non-profit organisations that support and cultivate social entrepreneurs. We rely on a unique data set from survey research on non-profit initiatives across three U.S. Census Regions. Results indicate that the characteristics of non-profit organisations vary in their reliance on a variety of revenue resources and governance arrangements, as well as in their diverse policy focus. They also provide an extensive and diverse set of services that supports the ideas and efforts of social entrepreneurs. [ABSTRACT FROM AUTHOR]

The design and optimization of laser-Compton x-ray systems based on compact distributed charge accelerator structures can enable micron-scale imaging of disease and the concomitant production of beams of Very High Energy Electrons (VHEEs) capable of producing FLASH-relevant dose rates (∼ 10 Gy in less than 100 ns). The physics of laser-Compton x-ray scattering ensures that the x-rays produced by this process follow exactly the trajectory of the electrons from which the x-rays were produced, thus providing a route to not only compact VHEE radiotherapy but also image-guided, VHEE FLASH radiotherapy. This manuscript will review the compact accelerator architecture considerations that simultaneously optimize the production of laser-Compton x-rays from the collision of energetic laser pulses with high energy electrons and the production of high-bunch-charge VHEEs. The primary keys to this optimization are use of X-band RF accelerator structures which have been demonstrated to operate with over 100 MeV/m acceleration gradients. The operation of these structures in a distributed charge mode in which each radiofrequency (RF) cycle of the drive RF pulse is filled with a low-charge, high-brightness electron bunch is enabled by the illumination of a high-brightness photogun with a train of UV laser pulses synchronized to the frequency of the underlying accelerator system. The UV pulse trains are created by a patented pulse synthesis approach which utilizes the RF clock of the accelerator to phase and amplitude modulate a narrow band continuous wave (CW) seed laser. In this way it is possible to produce up to 10 µA of average beam current from the accelerator. Such high current from a compact accelerator enables production of sufficient x rays via laser-Compton scattering for clinical imaging and does so from a machine of “clinical” footprint. At the same time, the production of 1,000 or greater individual micro-bunches per RF pulse enables > 10 nC of charge to be produced in a macrobunch of < 100 ns. The design, construction, and test of the 100-MeV class prototype system in Irvine, CA is also presented.

Although the concept of an entrepreneurial ecosystem has become appealing to both academics and policy makers, few studies have measured the impact of entrepreneurial ecosystems on firm growth. Using quantitative data, this paper analyzes a local innovation ecosystem to identify the contribution of a regional ecosystem to firm growth. The results indicate that firms that intensively rely on ecosystem intermediary organizations tend to experience less growth. In other words, when it comes to supporting firm growth, 'the more the merrier' does not apply. [ABSTRACT FROM AUTHOR]

Research Summary: Accelerator programs provide valuable market feedback and education to participants that may improve startup performance. However, it is unclear whether the average effect of accelerator participation on startup performance post acceleration is positive, and if so, how this effect varies with accelerator program design. We analyze data from 8580 startups that made it past the initial selection stage at 408 accelerators in 176 countries between 2013 and 2019. We compare accelerated and non‐accelerated startups and find a positive average effect of accelerator participation on startup performance post acceleration. Moreover, we find that this effect varies substantially with program design, and depends on venture stage, industry, and founder expertise. Our findings highlight the impact of program design on the benefits that startups derive from accelerator participation. Managerial Summary: The purpose of this study is to determine whether participation in startup accelerator programs generally leads to improved startup performance post acceleration and how the benefits of participation might vary with the design of these programs. We analyze data from 8580 startups that applied to and passed the initial selection phase at 408 accelerators in 176 countries over multiple cohorts between 2013 and 2019. Our results indicate that on average, startups that participate in accelerators perform better than those that are also selected but not accelerated. Furthermore, we find that the benefits that startups gain from being accelerated vary with the design of the program. Our findings highlight the importance of accelerator program design in influencing the extent of improvement in startup performance post acceleration. [ABSTRACT FROM AUTHOR]

Photocathodes are key elements in high-brightness electron sources and ubiquitous in the operation of large-scale accelerators, although their operation is often limited by their quantum efficiency and lifetime. Here, we propose to overcome these limitations by utilizing direct-laser nanostructuring techniques on copper substrates, improving their efficiency and robustness for next-generation electron photoinjectors. When the surface of a metal is nanoengineered with patterns and particles much smaller than the optical wavelength, it can lead to the excitation of localized surface plasmons that produce hot electrons, ultimately contributing to the overall charge produced. In order to quantify the performance of laser-produced plasmonic photocathodes, we measured their quantum efficiency in a typical electron gun setup. Our experimental results suggest that plasmon-induced hot electrons lead to a significant increase in quantum efficiency, showing an overall charge enhancement factor of at least 4.5 and up to 25. A further increase in their efficiency was observed when combined with semiconductor thin-films deposited over the laser processed surfaces, pointing at potential pathways for further optimization. We demonstrate that simple laser-produced plasmonic photocathodes outperform standard metallic photocathodes, and can be directly produced in-situ at the electron gun level in vacuum environments and without any disruptive intervention. This approach could lead to unprecedented efficient and continuous operation of electron sources, and is useful in many applications across scientific disciplines requiring high average and peak current electron beams. [ABSTRACT FROM AUTHOR]

Corporate entrepreneurship is infused with power. Prior research has begun to shed light on the role of power in innovation contexts. Yet, we know much less about the day‐to‐day enactment of mundane power in corporate entrepreneurship, which, despite its partial subtlety, is no less consequential regarding decisions on pursuing or abandoning innovative ideas. This paper extends the literature on corporate entrepreneurship and power by exploring the discursive practices through which managers and employees of a corporate accelerator disciplined venture founders in the pursuit of innovative ideas. Based on a Foucauldian discourse analysis of ethnographic data, we show how a clash of entrepreneurship discourses invokes the day‐to‐day performance of three discursive practices—observing, exercising, and punishing—through which the accelerator's staff ensured that venture founders would adopt a dominant entrepreneurship discourse, with important implications for decisions on pursuing innovative ideas or not. These findings deepen our understanding of enacting mundane power in corporate entrepreneurship as well as the enablers and outcomes of such power enactment. We also outline the practical implications for emerging corporate innovation settings such as accelerators. [ABSTRACT FROM AUTHOR]

Investing in adolescents in Africa holds great promise for the development of the continent. The steps involved in identifying factors linked to interventions that may accelerate the attainment of multiple SDGs for adolescents in Nigeria are described. Data from a survey to investigate the well-being of 1800 adolescents aged 10–19 years in Southwest Nigeria was analysed. A four-step process was employed: 1) Mapping of variables deemed as suitable proxies for SDG targets; 2) Mapping hypothesised protective factors (accelerators) from the study instruments. Consequently, SDG targets related to elimination of hunger, good health, gender equality and peace; and seven accelerators (safe schools, parenting support, good mental health, no survival work, food security, stable childhood, and regular physical activity) were identified; 3) evaluating associations using bivariate analysis and multivariable logistic regression, 4) calculating adjusted probabilities. The mean age of the adolescents was 15.02 ± 2.27 years (48.6% female). Good mental health, not doing survival work, safe schools, stable childhood and parental support were significantly associated with at least two SDG targets. For example, food security was significantly associated with the highest number of SDG outcomes: one SDG target related to child survival (no substance use: x2 = 3.39, p = <0.001); three SDG targets related to educational outcomes (school progression: x2 = 5.68, p = 0.017, ability to concentrate in school: x2 = 26.92, p = <0.001, and school attendance: x2 = 25.89, p = <0.001); and four SDG targets related to child protection (no risky sexual behaviours: x2 = 16.14, p = <0.001, no perpetration of violence: x2 = 15.74, p = <0.001, no community violence: x2 = 39.06, p =<0.001, and no sexual abuse: x2 = 7.66, p = 0.006). Interventions centred around good mental health, not doing survival work, safe schools, small family size, stable childhood and parental support are potential accelerators for the attainment of SDG outcomes by adolescents living in Nigeria. [ABSTRACT FROM AUTHOR]

The Single Instruction Multiple Data (SIMD) architecture, supported by various high-performance computing platforms, efficiently utilizes data-level parallelism. The SIMD model is used in traditional CPUs, dedicated vector systems, and accelerators such as GPUs, vector extensions, and Xeon Phi. It provides performance throughput in computation-intensive and data-parallel applications. Despite the similarity of data-processing principles between these architectures, porting various programming models between the reviewed platforms is challenging. Furthermore, enhancing the programmability of these architectures is an important feature for utilizing their emerging computing power and simplifying programming complexity. This paper reviews the basic principles of optimization techniques to run asynchronous Multiple Instruction Multiple Data (MIMD) on SIMD accelerators. It also surveys several GPU programming paradigms and application programming interfaces (APIs) and classifies these frameworks into different groups based on their criteria. In addition, a review of studies that performed a comparison of the collaborative execution of GPUs with CPUs and Xeon Phi is presented in this paper. This study will be beneficial for developers and researchers in the field of computer architecture and parallel computing of intensive scientific applications, specifically for early-stage high-performance computing researchers, to obtain a brief overview of performance optimization opportunities as well as the challenges of existing SIMD platforms.

Heterogeneous nodes composed of a multicore CPU and accelerators are today’s norm in high-performance computing (HPC) platforms due to their superior performance and energy efficiency. Tools such as OpenCL and hybrid combinations such as OpenMP plus OpenACC are used for developing portable parallel programs for such nodes. However, these tools have some drawbacks, including a lack of compiler support for nested parallelism, performance portability, automatic heterogeneous workload distribution, user-friendly thread placement, and processor affinity essential to the portable performance of hybrid programs executing on such nodes. In this paper, we propose OpenH, a novel programming model and library API for developing portable parallel programs on heterogeneous hybrid servers composed of a multicore CPU and one or more different types of accelerators. OpenH integrates Pthreads, OpenMP, and OpenACC seamlessly to facilitate the development of hybrid parallel programs. An OpenH hybrid parallel program starts as a single main thread, creating a group of Pthreads called hosting Pthreads. A hosting Pthread then leads the execution of a software component of the program, either an OpenMP multithreaded component running on the CPU cores or an OpenACC (or OpenMP) component running on one of the accelerators of the server. The OpenH library provides API functions that allow programmers to get the configuration of the executing environment and bind the hosting Pthreads (and hence the execution of components) of the program to the CPU cores of the hybrid server to get the best performance. We illustrate the OpenH programming model and library API using two hybrid parallel applications based on matrix multiplication and 2D fast Fourier transform for the most general case of a hybrid hyperthreaded server comprising $p$ computing devices. Finally, we demonstrate the practical performance and energy consumption of OpenH for the hybrid parallel matrix multiplication application on a server comprising an Intel Icelake multicore CPU and two Nvidia A40 GPUs.

Initially, the growth of particle detectors was focused on the identification of particles, but new detector designs have made it possible to build new diagnostic techniques. Clinical settings and medical research facilities utilize cutting-edge methods developed from particle accelerators, detectors, and physics computers, including imaging technologies, accelerators specifically designed for cancer therapy, simulations, data analysis, and nuclear medicine. It is still obvious that research in nuclear and basic particle physics is what motivates and propels the development of particle detectors for medical applications. The applications of the particle physics detector in medical science will be the main topic of this paper. [ABSTRACT FROM AUTHOR]

In recent years, the rapid growth of technology-driven enterprises has become a pivotal driver of economic development globally. Central to this growth are incubators and accelerators, which have emerged as vital ecosystems for nurturing tech talent and fostering innovation. These institutions play a significant role in transforming raw ideas into scalable, sustainable businesses, providing a platform for entrepreneurs to refine their concepts and expand their market reach. This letter delves into the multifaceted role of incubators and accelerators in nurturing tech talent, highlighting their contributions to entrepreneurial success and regional economic development. In conclusion, incubators and accelerators play a pivotal role in nurturing tech talent and fostering innovation. By providing essential resources, mentorship, funding, and networking opportunities, these programs significantly enhance the success rates of startups and contribute to regional economic development. As the global tech landscape continues to evolve, it is imperative to continuously adapt and refine these models to meet the changing needs of entrepreneurs and to maximize their impact on the broader economy. The ongoing success of incubators and accelerators will undoubtedly remain a cornerstone of entrepreneurial growth and technological advancement in the years to come. [ABSTRACT FROM AUTHOR]

The multiple domains of development covered by the Sustainable Development Goals (SDGs) present a practical challenge for governments. This is particularly acute in highly resource-constrained settings which use a sector-by-sector approach to structure financing and prioritization. One potentially under-prioritized solution is to implement interventions with the potential to simultaneously improve multiple outcomes across sectors, what United Nations Development Programme refer to as development 'accelerators'. An increasing number of accelerators are being identified in the literature. There are, however, challenges associated with the evaluation and implementation of accelerators. First, as accelerators have multiple benefits, possibly in different sectors, they will be undervalued if the priority setting is conducted sector-by-sector. Second, even if their value is recognized, accelerators may not be adopted if doing so clashes with any of the multiple competing interests policymakers consider, of which efficiency/social desirability is but one. To illustrate the first challenge, and outline a possible solution, we conduct a cost-effectiveness analysis comparing the implementation of three sector-specific interventions to an accelerator, first using a sector-by-sector planning perspective, then a whole of government approach. The case study demonstrates how evaluating the cost-effectiveness of interventions sector-by-sector can lead to suboptimal efficiency rankings and overlook interventions that are efficient from a whole of government perspective. We then examine why recommendations based on a whole of government approach to evaluation are unlikely to be heeded. To overcome this second challenge, we outline a menu of existing and novel financing mechanisms that aim to address the mismatch between political incentives and logistical constraints in the priority setting and the economic evaluation evidence for cost-effective accelerators. These approaches to financing accelerators have the potential to improve efficiency, and in doing so, progress towards the SDGs, by aligning political incentives more closely with recommendations based on efficiency rankings. [ABSTRACT FROM AUTHOR]

Incubators and accelerators catalyze the launch of life science startups and have evolved from simple facilities to vibrant ecosystems offering research infrastructure, programs, and funding. Analysis of financing activities indicates the outperformance of incubator companies relative to accelerators in fundraising, mergers and acquisitions (M&As), and initial public offerings (IPOs), attributed to extended interactions with investors and peers. [ABSTRACT FROM AUTHOR]

The article presents the technology of multiple focusing of a cumulative jet and its directional action in a cumulative ammunition to enhance the cumulative flow without increasing the mass of the explosive charge. An increased cumulative flow is considered to increase its velocity. When a downhole charge explodes, rocks are destroyed by compression due to the high pressure of the explosion energy, resulting in a significant amount of crushed mass around the charge, which crumbles during overload and delivery and violates the environment. An increase in the mass of the borehole charge does not ensure the accuracy of the rebound and leads to an increase in the spread of rock mass, which reduces safety in places where blasting operations are carried out, as well as labor costs increase during dismantling and installation of equipment to preserve mining machines and electric power supply systems, and the volume of repair and restoration work increases. Taking into account the above drawback, a new accelerator design with a cascade-step action of a cumulative charge has been developed. The shape of the cumulative accelerator now has a streamlined volumetric shape, which increases from the fuse so as not to create air cushions and ensure the sealing of the bulk charge. The proposed innovative explosive technology can be used in mining and other industries to increase the productivity of blasting operations for destruction, crushing and accuracy of the destroyed rock mass to improve the environment in places of blasting without the release of oversized pieces. [ABSTRACT FROM AUTHOR]

In the sports industry, there is significant potential for the emergence of startups. However, startups in this sector have experienced various challenges and fluctuations. Therefore, the purpose of this study is to examine the factors that contribute to the acceleration of Sports Startups. The research was conducted using a mixed-methods approach, involving the participation of sports business experts and scholars. Data collection was carried out through purposive sampling, employing in-depth interviews with these experts. The qualitative data obtained were analyzed using the thematic analysis approach. Additionally, the identified factors were ranked using the Analytic Hierarchy Process (AHP). The findings revealed the existence of six categories of accelerators for sports startups. Notably, strengthening and optimizing the value chain emerged as the most crucial factor among these categories. Consequently, to enhance the growth and development of sports startups, it is imperative to establish a well-defined value chain and actively work towards its reinforcement. [ABSTRACT FROM AUTHOR]

Startup selection is an essential mechanism of how accelerators create value. Through in-depth case studies of 10 accelerators in Turkey, our research explores the selection process in accelerators. Our findings indicate that accelerators overcome their context's extreme uncertainty by involving various actors in the selection process and reducing the information asymmetries for investors and startups. Accelerators tend to select effortlessly coachable startups, willing to collaborate with accelerators, mentors, or other actors, and passionate enough to overcome the pressure of creating a business at a fast pace. Our research also exhibits that the selection process serves startups by directing and training them to transmit the right signals to receivers, primarily investors. Accelerators prefer to work with entrepreneurial teams that are coachable, passionate, and collaborative to vibrate the right signals. Similarly, the accelerators' selection process helps investors by decreasing signaling noise and mitigate information asymmetry. By doing so, accelerators contribute to a well-functioning and more effective entrepreneurship ecosystem. [ABSTRACT FROM AUTHOR]

Photocathodes are key elements in high-brightness electron sources and ubiquitous in the operation of large-scale accelerators, although their operation is often limited by their quantum efficiency and lifetime. Here, we propose to overcome these limitations by utilizing direct-laser nanostructuring techniques on copper substrates, improving their efficiency and robustness for next-generation electron photoinjectors. When the surface of a metal is nanoengineered with patterns and particles much smaller than the optical wavelength, it can lead to the excitation of localized surface plasmons that produce hot electrons, ultimately contributing to the overall charge produced. In order to quantify the performance of laser-produced plasmonic photocathodes, we measured their quantum efficiency in a typical electron gun setup. Our experimental results suggest that plasmon-induced hot electrons lead to a significant increase in quantum efficiency, showing an overall charge enhancement factor of at least 4.5 and up to 25. A further increase in their efficiency was observed when combined with semiconductor thin-films deposited over the laser processed surfaces, pointing at potential pathways for further optimization. We demonstrate that simple laser-produced plasmonic photocathodes outperform standard metallic photocathodes, and can be directly produced in-situ at the electron gun level in vacuum environments and without any disruptive intervention. This approach could lead to unprecedented efficient and continuous operation of electron sources, and is useful in many applications across scientific disciplines requiring high average and peak current electron beams.

Recent research on start-up accelerators has drawn attention to the central importance of social resource exchange among peers for entrepreneurial success. But such peer relationships contain both cooperative and competitive elements, making accelerators a prime example of a mixed-motive context in which successful generalized exchange—unilateral giving without expectations of direct reciprocity—is not a given. In our ethnographic study of a Silicon Valley accelerator, we sought to explore how generalized exchange emerges and evolves over time. Employing an abductive, sequential mixed-methods approach, we develop a process model that helps explain how a system of generalized exchange may or may not emerge. At the core of this model are the interaction rituals within social events that come to create distinct exchange expectations, which are either aligned or incompatible with generalized exchange, resulting in fulfilled or failed exchanges in subsequent encounters. Whereas fulfilled exchanges can kickstart virtuous exchange dynamics and a thriving generalized exchange system, failed exchanges trigger vicious exchange dynamics and an unstable social order. These findings bring clarity to the puzzle of how some generalized exchange systems overcome the social dilemma in mixed-motive contexts by highlighting the central role of alignment between structure and process. [ABSTRACT FROM AUTHOR]

The effect of vulcanization accelerators on the structure and properties of rubbers based on Hydrin T6000 epichlorohydrin rubber was studied. As accelerators, we used mercaptobenzthiazole (MBT) in the amount of 1.5 pts. wt., tetramethylthiuram disulfide (TMTD) in the amount of 0.5–1.5 pts. wt., and N,N'‑diphenylguanidine (DPG) in the amount of 0.5–1.5 pts. wt., which represent a triple system of accelerators. The choice of accelerators is based on the possibility of obtaining a vulcanization spatial structure of different sulfide content: thiuram group accelerators promote the formation of mono- and disulfide bonds; guanidine group, polysulfide bonds; and thiazole group, from carbon-carbon to polysulfide with varying degrees of sulfide. According to the results of the study of physical and mechanical properties, the determination of the parameters of the spatial grid, and the study of the dynamic behavior of rubber, differences were revealed owing to the formation of a spatial structure with different types of crosslinks and density. It is shown that rubber containing 1.5 pts. wt. MBT, 0.5 pts. wt. DFG, and 0.5–1.0 pts. wt. TMTD possess the best set of properties owing to the manifestation of a synergistic effect on the formation of a vulcanization network of a certain density and the ratio of poly-, di-, and monosulfide crosslinks. Thus, the use of a group of accelerators with different functional effects makes it possible to obtain vulcanizates with an optimal set of technological and operational properties. [ABSTRACT FROM AUTHOR]

Sparse tensor algorithms are becoming widespread, particularly in the domains of deep learning, graph and data analytics, and scientific computing. Current high-performance broad-domain architectures, such as GPUs, often suffer memory system inefficiencies by moving too much data or moving it too far through the memory hierarchy. To increase performance and efficiency, proposed domain-specific accelerators tailor their architectures to the data needs of a narrow application domain, but as a result cannot be applied to a wide range of algorithms or applications that contain a mix of sparse and dense algorithms. This article proposes Symphony, a hybrid programmable/specialized architecture that focuses on the orchestration of data throughout the memory hierarchy to simultaneously reduce the movement of unnecessary data and data movement distances. Key elements of the Symphony architecture include (1) specialized reconfigurable units aimed not only at roofline floating-point computations but also at supporting data orchestration features, such as address generation, data filtering, and sparse metadata processing; and (2) distribution of computation resources (both programmable and specialized) throughout the on-chip memory hierarchy. We demonstrate that Symphony can match non-programmable ASIC performance on sparse tensor algebra and provide 31× improved runtime and 44× improved energy over a comparably provisioned GPU for these applications. [ABSTRACT FROM AUTHOR]