Frequency selective surface with better polarization independency for arbitrary incident angle

This paper investigates the frequency-selective property of a planar layer consisting of period arrays both theoretically and experimentally for different polarizations at arbitrary incident angle. The novel element is designed by loading the rectangular microstrip element with L-shaped conducting patch at its two ends. Based on the spectral-domain method, the frequency response including angle effect and polarization effect of the frequency selective surface （FSS） structure are analysed and the plots of the frequency versus transmission coefficient are obtained. As a result of the numerical analysis, it is shown that if the source polarization is changed, polarization-independence of previous FSS design can be achieved only for normal incidence, which limits most FSS applications. But in our proposed structure, the better polarization-independency for arbitrary incident angle can be achieved. It is observed that the simulated result comes very close to the experimental result.

在特定领域进一步赋予人类权力并重新思考AGI测试

Artificial intelligence(AI)has emerged as a transformative force with the potential to positively impact every facet of society.One of its most profound applications lies in its ability to empower individuals within communities by leveraging their strengths,promoting independence,and aiding them in achieving their goals.Human uses for AI have grown across every aspect of society;from language generation to molecular synthesis,AI has begun to permeate every aspect of our lives.

Cosmology-Independent Photon Mass Limits from Localized Fast Radio Bursts by Using Artificial Neural Networks

A hypothetical photon mass m_(γ) can produce a frequency-dependent vacuum dispersion of light, which leads to an additional time delay between photons with different frequencies when they propagate through a fixed distance. The dispersion measure and redshift measurements of fast radio bursts(FRBs) have been widely used to constrain the rest mass of the photon. However, all current studies analyzed the effect of the frequency-dependent dispersion for massive photons in the standard ΛCDM cosmological context. In order to alleviate the circularity problem induced by the presumption of a specific cosmological model based on the fundamental postulate of the masslessness of photons, here we employ a new model-independent smoothing technique, artificial neural network(ANN), to reconstruct the Hubble parameter H(z) function from 34 cosmic-chronometer measurements.By combining observations of 32 well-localized FRBs and the H(z) function reconstructed by ANN, we obtain an upper limit of m_(γ) ≤ 3.5 × 10^(-51)kg, or equivalently m_(γ) ≤ 2.0 × 10^(-15)eV/c^(2)(m_(γ) ≤ 6.5 × 10^(-51)kg, or equivalently m_(γ) ≤ 3.6 × 10^(-15)eV/c_(2)) at the 1σ(2σ) confidence level. This is the first cosmology-independent photon mass limit derived from extragalactic sources.

Origin of the Dashuigou independent tellurium deposit at Qinghai–Xizang Plateau: constraints from the light stable isotopes C, O, and H

By studying the light isotopic compositions of carbon,oxygen,and hydrogen,combined with previous research results on the ore-forming source of the deposit,the authors try to uncover its metallogenic origin.The δ^(18)O and δ^(13)C isotope signatures of dolomite samples vary between 10.2 and 13.0‰,and between−7.2 and−5.2‰,respectively,implying that the carbon derives from the upper mantle.δD and δ^(18) O of quartz,biotite,and muscovite from diff erent ore veins of the deposit vary between−82 and−59‰,and between 11.6 and 12.4‰,respectively,implying that the metallogenic solutions are mainly magmatic.According to the relevant research results of many isotope geologists,the fractionation degree of hydrogen isotopes increases as the depth to the Earth’s core increases,and the more diff erentiated the hydrogen isotopes are,the lower their values will be.In other words,mantle-derived solutions can have extremely low hydrogen isotope values.This means that the δD‰ value−134 of the pyrrhotite sample numbered SD-34 in this article may indicate mantle-derived oreforming fl uid of the deposit.The formation of the Dashuigou tellurium deposit occurred between 91.71 and 80.19 Ma.

A Constrained Local Neighborhood Approach for Efficient Markov Blanket Discovery in Undirected Independent Graphs

When learning the structure of a Bayesian network,the search space expands significantly as the network size and the number of nodes increase,leading to a noticeable decrease in algorithm efficiency.Traditional constraint-based methods typically rely on the results of conditional independence tests.However,excessive reliance on these test results can lead to a series of problems,including increased computational complexity and inaccurate results,especially when dealing with large-scale networks where performance bottlenecks are particularly evident.To overcome these challenges,we propose a Markov blanket discovery algorithm based on constrained local neighborhoods for constructing undirected independence graphs.This method uses the Markov blanket discovery algorithm to refine the constraints in the initial search space,sets an appropriate constraint radius,thereby reducing the initial computational cost of the algorithm and effectively narrowing the initial solution range.Specifically,the method first determines the local neighborhood space to limit the search range,thereby reducing the number of possible graph structures that need to be considered.This process not only improves the accuracy of the search space constraints but also significantly reduces the number of conditional independence tests.By performing conditional independence tests within the local neighborhood of each node,the method avoids comprehensive tests across the entire network,greatly reducing computational complexity.At the same time,the setting of the constraint radius further improves computational efficiency while ensuring accuracy.Compared to other algorithms,this method can quickly and efficiently construct undirected independence graphs while maintaining high accuracy.Experimental simulation results show that,this method has significant advantages in obtaining the structure of undirected independence graphs,not only maintaining an accuracy of over 96%but also reducing the number of conditional independence tests by at least 50%.This significant performance improvement is due to the effective constraint on the search space and the fine control of computational costs.

An Integrated Control Framework for Torque Vectoring and Active Suspension System

Four-wheel independently driven electric vehicles(FWID-EV)endow a flexible and scalable control framework to improve vehicle performance.This paper integrates the torque vectoring and active suspension system(ASS)to enhance the vehicle’s longitudinal and vertical motion control performance.While the nonlinear characteristic of the tire model leads to a relatively heavier computational burden.To facilitate the controller design and ease the load,a half-vehicle dynamics system is built and simplified to the linear-time-varying(LTV)model.Then a model predictive controller is developed by formulating the objective function by comprehensively considering the safety,energy-saving and comfort requirements.The in-wheel motor efficiency and the power loss of tire slip are treated as optimization indices in this work to reduce energy consumption.Finally,the effectiveness of the proposed controller is verified through the rapid-control-prototype(RCP)test.The results demonstrate the enhancement of the energy-saving as well as comfort on the basis of vehicle stability.

Resting-state brain network remodeling after different nerve reconstruction surgeries:a functional magnetic resonance imaging study in brachial plexus injury rats

Distinct brain remodeling has been found after different nerve reconstruction strategies,including motor representation of the affected limb.However,differences among reconstruction strategies at the brain network level have not been elucidated.This study aimed to explore intranetwork changes related to altered peripheral neural pathways after different nerve reconstruction surgeries,including nerve repair,endto-end nerve transfer,and end-to-side nerve transfer.Sprague–Dawley rats underwent complete left brachial plexus transection and were divided into four equal groups of eight:no nerve repair,grafted nerve repair,phrenic nerve end-to-end transfer,and end-to-side transfer with a graft sutured to the anterior upper trunk.Resting-state brain functional magnetic resonance imaging was obtained 7 months after surgery.The independent component analysis algorithm was utilized to identify group-level network components of interest and extract resting-state functional connectivity values of each voxel within the component.Alterations in intra-network resting-state functional connectivity were compared among the groups.Target muscle reinnervation was assessed by behavioral observation(elbow flexion)and electromyography.The results showed that alterations in the sensorimotor and interoception networks were mostly related to changes in the peripheral neural pathway.Nerve repair was related to enhanced connectivity within the sensorimotor network,while end-to-side nerve transfer might be more beneficial for restoring control over the affected limb by the original motor representation.The thalamic-cortical pathway was enhanced within the interoception network after nerve repair and end-to-end nerve transfer.Brain areas related to cognition and emotion were enhanced after end-to-side nerve transfer.Our study revealed important brain networks related to different nerve reconstructions.These networks may be potential targets for enhancing motor recovery.

Are cities greener because of innovation?Independent innovation policy and green economic efficiency

The national independent innovation demonstration zone(NIIDZ)is an independent innovation policy that plays a crucial role in implementing strategies.Given the importance of the NIIDZ,this study uses panel data of 278 prefecture-level cities in China from 2006 to 2020 and empirically examines the effect and internal mechanism of the NIIDZ on green economic efficiency(GEE)using the difference-in-difference model(DID).The results show that the NIIDZ effectively enhances the growth of GEE,and the results remain valid through several robustness tests,such as year-by-year propensity score matching.The transmission mechanism suggests that the NIIDZ indirectly drives GEE by accelerating scientific and technological investment,promoting talent concentration,and optimizing the industrial structure.Moreover,heterogeneity analysis reveals that the promotion effect of the NIIDZ on GEE is more prominent in the eastern region and high green development level areas.The study’s findings can serve as a reference for China to further utilize the policy effectiveness of the NIIDZ and accelerate the high-quality development of the green economy in the future.

Automatic SOC Equalization Strategy of Energy Storage Units with DC Microgrid Bus Voltage Support

In this paper,an improved sag control strategy based on automatic SOC equalization is proposed to solve the problems of slow SOC equalization and excessive bus voltage fluctuation amplitude and offset caused by load and PV power variations in a stand-alone DC microgrid.The strategy includes primary and secondary control.Among them,the primary control suppresses the DC microgrid voltage fluctuation through the I and II section control,and the secondary control aims to correct the P-U curve of the energy storage system and the PV system,thus reducing the steady-state bus voltage excursion.The simulation results demonstrate that the proposed control strategy effectively achieves SOC balancing and enhances the immunity of bus voltage.The proposed strategy improves the voltage fluctuation suppression ability by approximately 39.4%and 43.1%under the PV power and load power fluctuation conditions,respectively.Furthermore,the steady-state deviation of the bus voltage,△U_(dc) is only 0.01–0.1 V,ensuring stable operation of the DC microgrid in fluctuating power environments.

Neuropathological characteristics of abnormal white matter functional signaling in adolescents with major depression

BACKGROUND Major depression disorder(MDD)constitutes a significant mental health concern.Epidemiological surveys indicate that the lifetime prevalence of depression in adolescents is much higher than that in adults,with a corresponding increased risk of suicide.In studying brain dysfunction associated with MDD in adolescents,research on brain white matter(WM)is sparse.Some researchers even mistakenly regard the signals generated by the WM as noise points.In fact,studies have shown that WM exhibits similar blood oxygen level-dependent signal fluctuations.The alterations in WM signals and their relationship with disease severity in adolescents with MDD remain unclear.AIM To explore potential abnormalities in WM functional signals in adolescents with MDD.METHODS This study involved 48 adolescent patients with MDD and 31 healthy controls(HC).All participants were assessed using the Patient Health Questionnaire-9 Scale and the mini international neuropsychiatric interview(MINI)suicide inventory.In addition,a Siemens Skyra 3.0T magnetic resonance scanner was used to obtain the subjects'image data.The DPABI software was utilized to calculate the WM signal of the fractional amplitude of low frequency fluctuations(fALFF)and regional homogeneity,followed by a two-sample t-test between the MDD and HC groups.Independent component analysis(ICA)was also used to evaluate the WM functional signal.Pearson’s correlation was performed to assess the relationship between statistical test results and clinical scales.RESULTS Compared to HC,individuals with MDD demonstrated a decrease in the fALFF of WM in the corpus callosum body,left posterior limb of the internal capsule,right superior corona radiata,and bilateral posterior corona radiata[P<0.001,family-wise error(FWE)voxel correction].The regional homogeneity of WM increased in the right posterior limb of internal capsule and left superior corona radiata,and decreased in the left superior longitudinal fasciculus(P<0.001,FWE voxel correction).The ICA results of WM overlapped with those of regional homogeneity.The fALFF of WM signal in the left posterior limb of the internal capsule was negatively correlated with the MINI suicide scale(P=0.026,r=-0.32),and the right posterior corona radiata was also negatively correlated with the MINI suicide scale(P=0.047,r=-0.288).CONCLUSION Adolescents with MDD involves changes in WM functional signals,and these differences in brain regions may increase the risk of suicide.

The Rise and Impacts of Kenya’s Hustler Movement

On December 12,2023,Kenya celebrated its 60th anniversary of independence.Since independence,Kenya’s political operations have long been characterized by tribal politics,and during the 2022 elections,United Democratic Alliance(UDA)presidential candidate William Samoei Ruto advocated a Hustler Movement with a platform focused on serving the interests of the underprivileged.The Movement,with its policy orientation of responding to the concerns of the hustler(refer to those forced to squeeze out a meagre living on the margins of society comparing to people from Kenya’s big-name families),seeks to move electoral politics away from the previous competition at the tribal and regional levels,and to construct an issue-oriented mode of political operation,which has given a new meaning to the development of Kenyan politics.Ruto became president in September 2022 after the Hustler Movement gained broad social support.Over the past years,the Ruto government has transformed the Hustler Movement’s policy ideas into a program of governance,reshaping Kenya’s political development agenda in practical terms.The influence of the Hustler Movement has become more and more visible,deeply reflecting the trend of Kenya’s political development over the past 60 years of independence.

A Bayesian Mixture Model Approach to Disparity Testing

The topic of this article is one-sided hypothesis testing for disparity, i.e., the mean of one group is larger than that of another when there is uncertainty as to which group a datum is drawn. For each datum, the uncertainty is captured with a given discrete probability distribution over the groups. Such situations arise, for example, in the use of Bayesian imputation methods to assess race and ethnicity disparities with certain insurance, health, and financial data. A widely used method to implement this assessment is the Bayesian Improved Surname Geocoding (BISG) method which assigns a discrete probability over six race/ethnicity groups to an individual given the individual’s surname and address location. Using a Bayesian framework and Markov Chain Monte Carlo sampling from the joint posterior distribution of the group means, the probability of a disparity hypothesis is estimated. Four methods are developed and compared with an illustrative data set. Three of these methods are implemented in an R-code and one method in WinBUGS. These methods are programed for any number of groups between two and six inclusive. All the codes are provided in the appendices.

FOCUS

Presidents’Meeting.Chinese President Xi Jinping holds talks with his French counterpart,Emmanuel Macron,at theÉlysée Palace in Paris on the afternoon of May 6,2024.In the picture,President Xi Jinping and his wife Peng Liyuan pose for a group photo with President Emmanuel Macron and his wife Brigitte Macron.As the world goes through transformation and turbulence not seen in a century,China and France should uphold independence and jointly prevent a"new Cold War"or bloc confrontation,President Xi said during their talk.

SCIENCE AND TECHNOLOGY

New Superconducting Quantum Computer Goes into Operation.Origin Wukong,China's independently-developed third-generation superconducting quantum computer,went into operation on January 6 at Origin Quantum Computing Technology(Hefei)Co.,Ltd.in east China's Anhui Province.

Influence of Energy Policies on Development Path of US Oil Companies

Focused on“energy security”,US energy policies have undergone a multi-stage evolution.The main line has shifted from ensuring the oil and gas supply to achieving energy independence,and then to diversified development under a broader concept of energy security.The development path of US oil and gas companies is guided and influenced by series of policies.Represented by ExxonMobil and Chevron,US oil companies are maintaining a long commitment to the oil and gas business,especially unconventional resources such as shale gas and shale oil.Different from their European counterparts,US oil companies have chosen CCS/CCUS as their primary method for achieving carbon neutrality.As for the new energy business,the US oil giants are showing more interest in raw materials such as lithium resources rather than the power generation business.

欧盟在中美欧互动中的多重角色与中欧关系

In China-US-Europe interaction,the EU plays a threefold role of a stakeholder and power balancer,an informal ally,and an ambivalent partner.These roles interact and shape the EU’s unique identity and interest orientation.Facing fierce ChinaUS competition,the EU’s current strategy is to demonstrate its autonomy and independence,avoid choosing sides,and balance and mediate China-US relations.In strategizing its diplomacy toward Europe,China also needs to consider,as it sees fit,expanding its opening-up to Europe,deepen China-EU cooperation,and ensure that China-EU relations are more cooperative than competitive.

Books

An African History of AfricaThe statement“Everyone is originally from Africa,and this book is therefore for everyone”sets the tone for Zeinab Badawi’s groundbreaking exploration of Africa’s history.Too often overshadowed by Western narratives,Africa’s rich and complex past is brought to light in this fascinating journey through time.Badawi takes readers on a captivating odyssey,tracing Africa’s history from the origins of humanity to the present day.Along the way,she delves into the stories of ancient civilizations,medieval empires,remarkable leaders,and pivotal moments of conquest and independence.Drawing on interviews with historians,anthropologists,archaeologists,and local storytellers from more than thirty African countries,Badawi uncovers hidden histories and amplifies the voices of Africans themselves.

Creating a New Discourse

Knowledge sharing plays a key role in deepening China-Africa exchanges.With growing economic vitality,African nations are placing more emphasis on building their own knowledge systems.China firmly supports African countries in achieving intellectual independence,which is essential for their self-development and modernisation.

Improvement in Patient Mobility Following Short-Term Rehabilitation in Skilled Nursing Facilities

Background: Mobility in older adults can be impaired after acute illness or hospitalization, and the level of severity can be used as a predictor of one’s ability to return to independent living. Patients are often referred to skilled nursing facilities in hopes of improving their mobility. We wanted to prove that rehabilitative services at Skilled Nursing Facilities improve overall outcomes. Methods: We conducted a retrospective analysis of data from 4612 patients admitted for short-term rehabilitation in a large nursing home chain in California. Our aim was to determine whether patients’ mobility scores, as measured by rehabilitative staff, significantly improved by time of discharge compared to their scores at admission. Mobility scores were rated from 1 to 6, with 1 being the most dependent on aid and 6 being the most independent, over a variety of tasks at admission and compared to scores at discharge. Pearson’s correlations were performed to determine if there were significant relationships in the data: the Pearson’s correlation coefficient was used to describe the relationships between patient admission to a skilled nursing facility and medical improvement upon discharge. Results: The study demonstrated a statistically significant improvement in patients’ mobility scores upon discharge, with Medicare insured patients showing on average 57% improvement and Managed Care insured patients showing on average 59% improvement. Additionally, admission scores appeared to be predictive of the patient’s outcome at discharge. Conclusions: The values and consistency of improvement support the use of acute rehabilitative services in skilled nursing facilities. An equation can be formulated that evaluates patients’ estimated mobility statuses upon discharge from facilities based on their conditions on their arrivals. With this, new interventions can be studied and compared to the current standard of care by using these measurements. They can determine if further improvements can be made to increase patient outcomes.

Binding Number and Fractional k-Factors of Graphs

In this paper, we consider the relationship between the binding number and the existence of fractional k-factors of graphs. The binding number of G is defined by Woodall as bind(G)=min{ | NG(X) || X |:∅≠X⊆V(G) }. It is proved that a graph G has a fractional 1-factor if bind(G)≥1and has a fractional k-factor if bind(G)≥k−1k. Furthermore, it is showed that both results are best possible in some sense.