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In this article we present a theoretical investigation on an experimental design of a laser wakefield accelerator in which electron bunches from a photocathode radio frequency linac are injected into a capillary discharge plasma channel just in front of a few tens of terawatt drive laser pulse. The electron bunch, with a kinetic energy of 2.9 MeV and an energy chirp imposed by the linac, is magnetically compressed by a factor of 8 to a duration of 250 fs, and is magnetically focused into the plasma channel where it matches the spot size of the drive laser (≈30 μm). The dynamics of the bunch, starting from the photocathode, through the linac, along the beam transportation line, through the magnetic compressor, and its focusing into the plasma channel are comprehensively simulated with the general particle tracer code. Further, we use our three-dimensional numerical codes to calculate the laser wakefield and to determine and optimize the trapping and acceleration of the injected bunch in the wakefield. We show that, injecting a 5 pC electron bunch of 250 fs duration, the experiment should deliver an electron bunch of approximately 744 MeV energy, with 1.1% relative energy spread, and with an extremely short duration (6 fs), after acceleration in a 5.4 cm long plasma channel. [ABSTRACT FROM AUTHOR]

Modeling free-electron laser (FEL) oscillators requires calculation of both the light-beam interaction within the undulator and the light propagation outside the undulator. We have developed a paraxial optical propagation code that can be combined with various existing models of gain media, for example, Genesis 1.3 for FELs, to model oscillators with full paraxial wave propagation within the resonator. A flexible scripting interface is used both to describe the optical resonator and to control the codes for propagation and amplification. To illustrate its capabilities, we numerically investigate two significantly different FEL oscillators: the free-electron laser for infrared experiments (FELIX) system and the vacuum-ultraviolet (VUV)-FEL oscillator of the proposed high-gain fourth generation light source. For the FELIX system, we find that diffraction losses are a considerable part of the single-pass cavity loss (at a wavelength of 40 μm). We also demonstrate that a resonator with hole coupling may be a viable alternative to a standard resonator with transmissive optics for the high gain VUV-FEL oscillator. [ABSTRACT FROM AUTHOR]

Discusses the use of K-Te photocathodes deposited on an Mo substrate as an electron source in the free electron laser of the University of Twente. Measurement of cathode lifetimes; Quantum efficiency; Rejuvenation of degraded K-Te cathodes.

Despite the growing accessibility of international grain and oilseed markets, high production costs and trade frictions are still prevalent, contributing to regional heterogeneities in the landed cost of grain imports. Here we quantify the landed cost for six grain commodities across 3,500 administrative regions, capturing regional cost differences to produce grain and transport it across international borders. We find large heterogeneities in the costs of imported grain, which are highest in Oceania, Central America and landlocked Africa. While some regions have uniform landed costs across sourcing locations, others face cost variations across trading partners, showing large inequalities in access. We find that most regions could benefit from a targeted approach to reduce landed cost while others benefit from a mixed strategies approach. Our results highlight that spatial information on production, trade and transport is essential to inform policies aiming to build an efficient and resilient global agricultural commodity trade system., Competing Interests: Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

Recent phenomena such as pandemics, geopolitical tensions, and climate change-induced extreme weather events have caused transportation network interruptions, revealing vulnerabilities in the global supply chain. A salient example is the March 2021 Suez Canal blockage, which delayed 432 vessels carrying cargo valued at $92.7 billion, triggering widespread supply chain disruptions. Our ability to model the spatiotemporal ramifications of such incidents remains limited. To fill this gap, we develop an agent-based complex network model integrated with frequently updated maritime data. The Suez Canal blockage is taken as a case study. The results indicate that the effects of such blockages go beyond the directly affected countries and sectors. The Suez Canal blockage led to global losses of about $136.9 ($127.5-$147.3) billion, with India suffering 75% of these losses. Global losses show a nonlinear relationship with the duration of blockage and exhibit intricate trends post blockage. Our proposed model can be applied to diverse blockage scenarios, potentially acting as an early-alert system for the ensuing supply chain impacts. Furthermore, high-resolution daily data post blockage offer valuable insights that can help nations and industries enhance their resilience against similar future events., Competing Interests: The authors declare no competing interests., (© 2024 The Author(s).)

The implementation of large-scale containment measures by governments to contain the spread of the COVID-19 virus has resulted in large impacts to the global economy. Here, we derive a new high-frequency indicator of economic activity using empirical vessel tracking data, and use it to estimate the global maritime trade losses during the first eight months of the pandemic. We go on to use this high-frequency dataset to infer the effect of individual non-pharmaceutical interventions on maritime exports, which we use as a proxy of economic activity. Our results show widespread port-level trade losses, with the largest absolute losses found for ports in China, the Middle-East and Western Europe, associated with the collapse of specific supply-chains (e.g. oil, vehicle manufacturing). In total, we estimate that global maritime trade reduced by -7.0% to -9.6% during the first eight months of 2020, which is equal to around 206-286 million tonnes in volume losses and up to 225-412 billion USD in value losses. We find large sectoral and geographical disparities in impacts. Manufacturing sectors are hit hardest, with losses up to 11.8%, whilst some small islands developing states and low-income economies suffered the largest relative trade losses. Moreover, we find a clear negative impact of COVID-19 related school and public transport closures on country-wide exports. Overall, we show how real-time indicators of economic activity can inform policy-makers about the impacts of individual policies on the economy, and can support economic recovery efforts by allocating funds to the hardest hit economies and sectors., Competing Interests: The authors have declared that no competing interests exist.

Climate-induced food production shocks, like droughts, can cause food shortages and price spikes, leading to food insecurity. In 2007, a synchronous crop failure in Lesotho and South Africa-Lesotho's sole trading partner-led to a period of severe food insecurity in Lesotho. Here, we use extreme event attribution to assess the role of climate change in exacerbating this drought, going on to evaluate sensitivity of synchronous crop failures to climate change and its implications for food security in Lesotho. Climate change was found to be a critical driver that led to the 2007 crisis in Lesotho, aggravating an ongoing decline in food production in the country. We show how a fragile agricultural system in combination with a large trade-dependency on a climatically connected trading partner can lead to a nonlinear response to climate change, which is essential information for building a climate-resilient food-supply system now and in the future.

Background/aim: In order to define future chemoprevention strategies for adenomas or carcinomas in the pouch of patients with familial adenomatous polyposis (FAP), a 4-weeks intervention with (1) sulindac, (2) inulin/VSL#3, and (3) sulindac/inulin/VSL#3 was performed on 17 patients with FAP in a single center intervention study. Primary endpoints were the risk parameters cell proliferation and glutathione S-transferase (GST) detoxification capacity in the pouch mucosa; secondary endpoints were the short chain fatty acid (SCFA) contents, pH, and cytotoxicity of fecal water., Methods: Before the start and at the end of each 4-week intervention period, six biopsies of the pouch were taken and feces was collected during 24 h. Cell proliferation and GST enzyme activity was assessed in the biopsies and pH, SCFA contents, and cytotoxicity were assessed in the fecal water fraction. The three interventions (sulindac, inulin/VSL#3, sulindac/inulin/VSL#3) were compared with the Mann-Whitney U test., Results: Cell proliferation was lower after sulindac or VSL#3/inulin, the combination treatment with sulindac/inulin/VSL#3 showed the opposite. GST enzyme activity was increased after sulindac or VSL#3/inulin, the combination treatment showed the opposite effect. However, no significance was reached in all these measures. Cytotoxicity, pH, and SCFA content of fecal water showed no differences at all among the three treatment groups., Conclusion: Our study revealed non-significant decreased cell proliferation and increased detoxification capacity after treatment with sulindac or VSL#3/inulin; however, combining both regimens did not show an additional effect.

Background: It is widely assumed that the outcome of correctional treatment largely depends on the patient's treatment engagement; however, evidence for this notion is scarce., Aim: In this study, the Treatment Engagement Rating scale (TER) was used to investigate the relationship of a patient's treatment engagement with premature treatment termination and treatment outcome, defined as reduction of the risk of reoffending., Method: Employing a prospective design, this study addressed the relationship of the behavioural treatment engagement of correctional outpatients (N = 138) with treatment non-completion and treatment outcome, respectively., Results: Treatment engagement as measured by the TER emerged as an accurate predictor of treatment non-completion (area under the curve = 0.76; odds ratio = 4.1) and was also significantly correlated with treatment outcome (rho = 0.41). The prediction was more accurate for sex offenders than for violent offenders, for expulsion from the treatment than for dropout, and when treatment engagement was assessed closer to the end of the treatment., Conclusions: The study provides evidence that the outcome of correctional treatment depends to a substantial degree on the behavioural efforts that the patients make for the treatment. Periodic assessment of treatment engagement in correctional treatment facilities would be useful, and the TER seems to be a practical, reliable and valid instrument for this purpose.

We have performed an optimization study on a train of laser pulses in a Nd:YLF master-oscillator power amplifier chain. Instead of using a flat train of input pulses and proper timing of the input pulses with respect to the pump pulse to keep the output pulse flat, we used a pulse-shaping technique. Then the maximum gain could be used, resulting in a 70% increase in output pulse energy. We constructed a special feed-forward loop to control the temporal shape of the train. We compare the results with a computational model based on the rate equations in the Nd:YLF amplifiers.