Prospects and limitations of wakefield acceleration in solids

Advances in the generation of relativistic intensity pulses with wavelengths in the X-ray regime, through high harmonic generation from near-critical plasmas, opens up the possibility of X-ray driven wakefield acceleration. The similarity scaling laws for laser plasma interaction suggest that X-rays can drive wakefields in solid materials providing TeV/cm gradients, resulting in electron and photon beams of extremely short duration. However, the wavelength reduction enhances the quantum parameter $\chi$, hence opening the question of the role of non-scalable physics, e.g., the effects of radiation reaction. Using three dimensional Particle-In-Cell simulations incorporating QED effects, we show that for the wavelength $\lambda=5\,$nm and relativistic amplitudes $a_0=10$-100, similarity scaling holds to a high degree, combined with $\chi\sim 1$ operation already at moderate $a_0\sim 50$, leading to photon emissions with energies comparable to the electron energies. Contrasting to the generation of photons with high energies, the reduced frequency of photon emission at X-ray wavelengths (compared to at optical wavelengths) leads to a reduction of the amount of energy that is removed from the electron population through radiation reaction. Furthermore, as the emission frequency approaches the laser frequency, the importance of radiation reaction trapping as a depletion mechanism is reduced, compared to at optical wavelengths for $a_0$ leading to similar $\chi$.Comment: 9 pages, 7 figure

The study of prevalence of metabolic syndrome among nurses of Shahid Mohammadi Hospital of Bandar Abbas city, Iran

زمینه و هدف: سندرم متابولیک مجموعه‌ای از عواملی نظیر چاقی شکمی، فشارخون بالا، قند خون بالا، تری گلیسیرید بالا و لیپوپروتئین پر چگال (HDL) پایین می‌باشد که ریسک دیابت، بیماری‌های قلبی و سکته‌های مغزی را افزایش می‌دهد. هدف از مطالعه حاضر بررسی شیوع سندرم متابولیک در بین پرستاران بیمارستان شهید محمدی بندرعباس است. روش بررسی: این مطالعه، یک مطالعه توصیفی- مقطعی است که بر روی 197 نفر از پرستاران بیمارستان شهید محمدی شهر بندرعباس طی سال 93-92 صورت گرفته است. فراوانی سندرم متابولیک با معیارهای انجمن ملی قلب/ موسسه قلب، ریه، و خون (AHA/ NHLB)، فدراسیون بین‌المللی دیابت (IDF)، برنامه ملی آموزش کلسترول- پانل 3 NCEP (ATP III) و معیار ایرانی سندرم متابولیک ارزیابی گردید. تجزیه و تحلیل داده‌ها با استفاده از روش‌های آماری توصیفی، کای- دو، تی تست، آزمون من- ویتنی و با نرم‌افزار SPSS انجام شد. یافته‌ها: شیوع سندرم متابولیک در پرستاران، بر اساس معیار NCEP (ATP III) 7/11، AHA/NHLBI 8/19، IDF 2/16 و معیار ایرانی 7/12 تشخیص داده شد. بر اساس معیار NCEP (ATP III) شیوع سندرم در بین مردان، شاغلین در اورژانس و شب‌کار بیشتر بود هرچند نتایج آن ازنظر آماری معنی‌دار نبود. نتایج آزمون من‌ویتنی نشان داد که تفاوت معنی‌داری ازنظر شاخص توده بدنی بین افراد دارای سندرم متابولیک و افراد سالم وجود دارد (001/0=P). نتیجه‌گیری: یافته‌های مطالعه نشان داد که شیوع سندرم متابولیک در بین پرستاران مشابه شیوع این سندرم در جهان است و این سندرم ارتباط معنی‌داری با سن، جنس، بخش کاری و شیفت کاری ندارد و تنها ارتباط معنی‌دار در این مطالعه با شاخص توده بدنی دیده ‌شده است و درنهایت این سندرم نیازمند توجه و تشخیص و درمان به‌موقع جهت افزایش سلامت پرستاران و کاهش ناتوانی و هزینه‌های ناشی از عوارض آن می‌باشد

A Legal Framework for Targeted Killing

I agree with much of what Professor Amos Guiora says, but I disagree with the method he uses to get there. And I believe the method matters. Guiora assesses targeting operations under an active self-defense paradigm, with elements from both the jus ad bellum (the law governing the use of force) and the jus in bello (the law governing the conduct of hostilities). Under Guiora\u27s paradigm. a state may target terrorism suspects in anticipatory self-defense if: (I) targeting is proportional to their threat; (2) collateral damage is minimized; (3) alternatives to targeting are infeasible; and (4) military necessity justifies the action. Guiora does not explain why that paradigm is the correct one. In fact. the ad bellum rules on defensive force probably do not govern Guiora\u27s poster-child case-the U.S. operation targeting Anwar al-Awlaki in Yemen. The jus ad bellum does not constrain the use of force by one state in another state where that second state consents. Yemen appears to have consented to the operation against Al-Awlaki. Moreover. neither the jus ad bellum nor the traditional jus in bello requires a state to consider alternatives to lethal force Guiora\u27s third criterion-if someone is a legitimate target. Finally. though Guiora argues that someone\u27s membership in al Qaeda is an insufficient basis for targeting him, many in bello experts treat membership in an organized armed group as dispositive. Rather than reflect existing law, then. Guiora\u27s model is some kind of \u27\u27hybrid.\u27\u27 He has presented his own normative vision on when targeting should be lawful. I assume that Guiora developed that hybrid because he believes that the traditional wartime paradigm--designed for interstate wars is poorly suited for the fight against al Qaeda. Similarly. I assume that Guiora rejects international law\u27s presumptive alternative-applying human rights law-because he believes that it. too, is inapposite. The human rights norms on targeting were developed for law enforcement settings. They would prohibit operations that Guiora would permit. For example, human rights law generally prohibits a state from targeting someone who is not on the verge of killing. Guiora does not require that kind of imminent threat. But Guiora does not explain why his model is preferable to the alternatives. Why should decision makers assess targeting operations using his four criteria, instead of applying the conventional wartime paradigm, the law enforcement paradigm of human rights law, or a hybrid advanced by someone else? In other work, I argue that the current method for assessing targeting operations-which requires first identifying the correct legal paradigm and then applying the norms as specified for that paradigm- is misguided. The method presumes that international law\u27s different paradigms operate independently and sometimes incompatibly. But as I demonstrate, three core principles animate all the international law on targeting: the jus in bello for combatants, the jus in bello for civilians, and human rights law

Orienting Graphs to Optimize Reachability

The paper focuses on two problems: (i) how to orient the edges of an undirected graph in order to maximize the number of ordered vertex pairs (x,y) such that there is a directed path from x to y, and (ii) how to orient the edges so as to minimize the number of such pairs. The paper describes a quadratic-time algorithm for the first problem, and a proof that the second problem is NP-hard to approximate within some constant 1+epsilon > 1. The latter proof also shows that the second problem is equivalent to ``comparability graph completion''; neither problem was previously known to be NP-hard

Enhanced Neural Responses to Imagined Primary Rewards Predict Reduced Monetary Temporal Discounting

The pervasive tendency to discount the value of future rewards varies considerably across individuals and has important implications for health and well-being. Here, we used fMRI with human participants to examine whether an individual's neural representation of an imagined primary reward predicts the degree to which the value of delayed monetary payments is discounted. Because future rewards can never be experienced at the time of choice, imagining or simulating the benefits of a future reward may play a critical role in decisions between alternatives with either immediate or delayed benefits. We found that enhanced ventromedial prefrontal cortex response during imagined primary reward receipt was correlated with reduced discounting in a separate monetary intertemporal choice task. Furthermore, activity in enhanced ventromedial prefrontal cortex during reward imagination predicted temporal discounting behavior both between- and within-individual decision makers with 62% and 73% mean balanced accuracy, respectively. These results suggest that the quality of reward imagination may impact the degree to which future outcomes are discounted. SIGNIFICANCE STATEMENT We report a novel test of the hypothesis that an important factor influencing the discount rate for future rewards is the quality with which they are imagined or estimated in the present. Previous work has shown that temporal discounting is linked to individual characteristics ranging from general intelligence to the propensity for addiction. We demonstrate that individual differences in a neurobiological measure of primary reward imagination are significantly correlated with discounting rates for future monetary payments. Moreover, our neurobiological measure of imagination can be used to accurately predict choice behavior both between and within individuals. These results suggest that improving reward imagination may be a useful therapeutic target for individuals whose high discount rates promote detrimental behaviors

Farmers' Practices in Developing Agricultural Land in Malaysia: is There an Islamic Microfinance Solution?

Objective – This paper attempts to highlight the farmers' lives in Malaysia and their problems in developing idle agricultural land.Methods - This paper is using descriptive and exploratory method of study which refer to the situation of agricultural sector in Malaysia.Results - The scheme aPLS (agricultural production and loss sharing) that proposed cannot stand alone in the traditional fiqh to be implemented now. Therefore, the combinations of aPLS contract with ujrah principle are really needed. This is important to ensure the flexibility of the contract that can offer a fully comprehensive scheme of Islamic agricultural finance.Conclusion – The land together with labour can be considered as a form of capital and therefore has a similarity to the contracts of mudaraba and musharaka. Hence, it can be said that these principles are “agricultural production and loss sharing (aPLS)” because land will naturally produce an output or a product. Muzara'a and musaqa therefore can be said to be contracts which are based on sharing output rather than sharing profit

Enhancing AmBC Systems with Deep Learning for Joint Channel Estimation and Signal Detection

The era of ubiquitous, affordable wireless connectivity has opened doors to countless practical applications. In this context, ambient backscatter communication (AmBC) stands out, utilizing passive tags to establish connections with readers by harnessing reflected ambient radio frequency (RF) signals. However, conventional data detectors face limitations due to their inadequate knowledge of channel and RF-source parameters. To address this challenge, we propose an innovative approach using a deep neural network (DNN) for channel state estimation (CSI) and signal detection within AmBC systems. Unlike traditional methods that separate CSI estimation and data detection, our approach leverages a DNN to implicitly estimate CSI and simultaneously detect data. The DNN model, trained offline using simulated data derived from channel statistics, excels in online data recovery, ensuring robust performance in practical scenarios. Comprehensive evaluations validate the superiority of our proposed DNN method over traditional detectors, particularly in terms of bit error rate (BER). In high signal-to-noise ratio (SNR) conditions, our method exhibits an impressive approximately 20% improvement in BER performance compared to the maximum likelihood (ML) approach. These results underscore the effectiveness of our developed approach for AmBC channel estimation and signal detection. In summary, our method outperforms traditional detectors, bolstering the reliability and efficiency of AmBC systems, even in challenging channel conditions.Comment: Accepted for publication in the IEEE Transactions on Communication

Pollen and seed morphology of rhinacanthus nees and hypoestes Sol. ex R. Br. (Acanthaceae) of Yemen

Pollens and seeds of Hypoestes and Rhinacanthus collected from different field localities in Taiz and Soqotra Island, Yemen were investigated by using light and scanning electron microscopes. Pollen grains of Hypoestes were prolate in equatorial view, lobate trigonal to lobate circular in polar view whereas those of Rhinacanthus were subspheroidal and rounded trigonal in polar view. The aperture was tricolporate and exine ornamentation was coarsely reticulate for all species in the two genera. Scanning electron microscopy and morphological observations showed that mature dry seeds of Hypoestes and Rhinacanthus have various sizes and shapes, the surface ornamentations observed were reticulate to cristate, an addition to the tuberculum and papillae. The three Hypoestes species differ in the seed structure which are useful for identification and their high structural diversity provides an important taxonomic value for species differentiation