Detecting short-term gravitational waves from post-merger hyper-massive neutron stars with a kilohertz detector

Gravitational waves emanating from binary neutron star inspirals,alongside electromagnetic transients resulting from the aftermath of the GW170817 merger,have been successfully detected.However,the intricate post-merger dynamics that bridge these two sets of observables remain enigmatic.This includes if,and when,the post-merger remnant star collapses to a black hole,and what are the necessary conditions to power a short gamma-ray burst,and other observed electromagnetic counterparts.Our focus is on the detection of gravitational wave(GW)emissions from hyper-massive neutron stars(NSs)formed through binary neutron star(BNS)mergers.Utilizing several kilohertz GW detectors,we simulate BNS mergers within the detection limits of LIGO-Virgo-KARGA O4.Our objective is to ascertain the fraction of simulated sources that may emit detectable post-merger GW signals.For kilohertz detectors equipped with a new cavity design,we estimate that approximately 1.1%-32%of sources would emit a detectable post-merger GW signal.This fraction is contingent on the mass converted into gravitational wave energy,ranging from 0.01M_(sun)to 0.1M_(sun).Furthermore,by evaluating other well-regarded proposed kilohertz GW detectors,we anticipate that the fraction can increase to as much as 2.1%-61%under optimal performance conditions.

Risk Assessment and Control in Medical Investment,Merger,and Acquisition

The risk assessment and control of medical investment,merger,and acquisition are crucial topics within the medical industry,encompassing various aspects of investment,merger,and acquisition within this sector.The process primarily targets the unique nature and associated risks of the medical industry,focusing on effective risk management and control strategies to facilitate the smooth progression of investment,merger,and acquisition activities.

Due Diligence in Mergers and Acquisitions in Emerging Markets： Evaluated Risk Factors From the Academic and Practical View

The obviously ever increasing number of corporate acquisitions in recent decades has improved the general knowledge and awareness of due diligence for both the industry and research. In the current challenging business environment, acquisitions face a higher degree of risk profiles, especially cross-border acquisitions in the emerging markets. Conducting a thorough due diligence investigation in the context of an acquisition is more important now than ever. In a broad analysis, this paper researches the key risk factors in the acquisition process and their assessment within a due diligence audit in the acquisition phase. The task of this paper is to match the academic and practical view in order to give a more complete understanding of risk factors to be covered in due diligence audit. The starting point is the research of academic findings which basically concentrate on common approaches considering financial, legal, commercial, and some other issues in domestic acquisitions and in developed countries. In contrast, this paper considers risk factors in cross-border and emerging markets transactions. In addition, a number of business consultants publish studies based on surveys on this topic which reflect typical risk factors based on experience of their customers being involved in cross-border acquisitions. Their risk assessment consists of specific regulatory, political, and other factors, which may lead to commercial and reputational impediments in cross-border acquisitions. The outcome of the comparison is a comprehended list of evaluated risk factors, whereby the academic findings are complemented and supported by the practical experience in the business consultant＇s studies. Moreover, the practical approach points to the fact that due diligence scope needs to be suited to the dynamics of the markets. The comparison and the comprehended list of evaluated risk factors call for a more integrated system of due diligence and show herein the research deficit. Hence, the novelty is the compendium of evaluated risk factors which should be assessed in the pre-acquisition phase. The originality of the paper is given by a unique analysis of academic work about acquisition due diligence literature and consultant studies from anonymized practical experience based on insider information.

A Critical Study of Mergers and Acquisitions

This article presents and analyses the theories with respect to mergers and acquisitions, and list why companies or firms need to be reorganised. Different types of mergers occur under different situations. Mergers between companies which have same products or services called horizontal mergers; mergers between companies which have buyer-seller relationship called vertical mergers; and companies which have different business fields always use conglomerate mergers. The main motive of companies or firms choosing merger or acquisition is synergy.

Modeling the factors that influence knowledge transfer in mergers and acquisitions

This paper constructs a model on the factors that influence knowledge transfer in mergers and acquisitions(M&A) and validates it via questionnaire surveys. Using 125valid collected questionnaires, multiple linear regression analysis and hierarchical regression analysis showed that five out of the ten factors had a positive effect on knowledge transfer effect. The ranking of factor importance, from high to low, was knowledge explicitness, relationship quality, learning intent, advanced transfer activities, and learning capability, which is fairly consistent with positive factors observed in other interorganizational knowledge transfer researches. Our results also showed that one of the control variables(size of acquired firm) had neither a direct or indirect effect on knowledge transfer in M&A. Additionally, our research found that knowledge distance and degree of M&A integration had a positive influence on knowledge transfer effect at the early stage after M&A, but had a negative influence at the late stage. Based on this research, several suggestions for knowledge transfer in M&A are proposed.

Enhancing mergers and acquisition quality,accelerating technological innovation and achieving the second leap of China's steel industry

Over the past 10 years, China＇s steel industry has made a substantial development in terms of scale, and has finally become a steel giant in the world. In the upcoming 10 years, fundamental changes will be made with the economic growth in China. Against this background, China＇ s steel industry will shift from a rapid development to a slow but sound development. In order to fulfill the second leap of China＇s steel industry, based on its current developing status and characteristics, and from the perspective of both national and corporate development, mergers and acquisition are both effective ways to raise the quality of the existing stock of asset in the steel industry, while technological innovation is the solid foundation for its second leap.

Selection of Mergers and Acquisitions by Foreign Capital in Open Economies

By a linear Cournot model, the factors associated with the integration of two firms are discussed in terms of their effects on the private surplus and the social welfare in economies with varying extent of openness. Meanwhile, the trade policy of the host government is taken into account. It is concluded that the more open the economy and the more intense the competition, the less profitable the integration; the most important determinant to the changes of the domestic social welfare is the industry strength of the host country. The host authority can enhance the domestic social welfare in two ways： to adjust the trade policy and to only approve the socially desirable cross-border mergers and acquisitions.

Mergers and Acquisitions: An Efficiency Evaluation

This article sheds light on how synergies arise through mergers and acquisitions (M&A). Enterprises go through the process of Mergers and Acquisitions (M&A) with the goal of improving performance, increasing efficiency and obtaining business synergy. Prior literature suggests that synergies could arise due to taxes, market power or efficiency improvements. This study evaluates the efficiency of M&A in Brazil among publicly-traded companies. We used models with multiple objectives from Goal Programming and Data Envelopment Analysis (GPDEA), employing accounting indicators as input and output variables, and thus evaluated the emergence of synergy gains. These models allow us to analyze and classify the M&A according to the efficiency obtained in such processes. Some of the M&A cases analyzed were mistakenly considered efficient when used traditional models. And, as expected, the GPDEA was proved to be superior to classical models;however it was noticed that few of the cases investigated were proved to be effective. We presented a new application for multi-objective approach that can be used to assess mergers and acquisitions. The dualapplication of GPDEA provided a greater understanding of efficiency generation in synergy creation by means of M&A.

Impact of mergers on the corporate performance of acquirer and target companies in India

Mergers and acquisitions become the major force in the changing environment. The policy of liberalization, decontrol and globalization of the economy has exposed the corporate sector to domestic and global competition. It is true that there is little scope for companies to learn from their past experience. Therefore, to determine the success of a merger, it is to be ascertained if there is financial gain from mergers. It is very important to study the liquidity performance of those companies to test whether those companies have sufficient liquid assets to meet its current obligations. The present study is limited to a sample of companies which underwent merger in the same industry during the period of 2002-2005 listed in one of the Indian stock exchange namely Bombay Stock Exchange. It is proposed to compare the liquidity performance of the thirteen sample acquirer and target companies before and after the period of mergers by using ratio analysis and t-test during the study period of three years. The study found that the shareholders of the acquirer companies increased their liquidity performance after the merger event.

Economic Policy Uncertainty and Corporate Mergers and Acquisitions

In recent years,the frequent adjustment of the government’s economic policies and the uncertainty of foreign economic situations have made the degree of uncertainty of China’s economic policies rise continuously.The increasing degree of policy uncertainty will inevitably affect the investment and financing decisions of micro enterprises.Then,how does economic policy uncertainty(EPU)affect mergers and acquisitions(M&A)behavior?What’s the mechanism?Based on the above questions,this paper uses the data of non-financial listed companies in the Shanghai and Shenzhen stock exchanges from 2008 to 2018 as a sample to explore the relationship between EPU and M&A.The study shows that rising EPU will promote corporate M&A behavior,and this effect is more significant in slow-growth companies.The relationship between EPU and M&A is affected by corporate governance,stock price volatility and financing constraints.Specifically,the company’s M&A size is more sensitive to EPU with higher level of corporate governance,higher level of stock price volatility,and lesser financing constraints.Further research shows that the rise of EPU will significantly promote the improvement of M&A performance in the short-term,but this effect does not exist in the long-term.Various robustness checks do not change the empirical results of this paper.

How Horizontal Mergers Improve Industrial Structure？

By reviewing the research on the effect of corporate merger, we find that knowledge is still limited to the effect of corporate merger on industrial structure. In this article, firstly we study the effect of horizontal merger on market structure, then explore the effect of market performance on industrial structure. Finally we present a new model that can explain how horizontal merger improves the adjustment of industrial structure.

The Efficient Market Theory and Mergers and Acquisitions （M＆As） Puzzle： Evidence From Italy

The efficient market theory is a central point in finance. If the capital market is competitive, the investors cannot expect superior gains from their investment strategies with respect to the risk profile. Event studies are an approach to verify the impact of the information on the stock prices. In an efficient market, stock prices should fully, promptly, and quickly capture all the information. Instead, the market shows phenomena of an under-reaction and over-reaction for both the short and the long run. The mergers and acquisitions （M＆As） are examples of anomalies. Often, the bidder companies record the negative abnormal returns for both the short and the long run. In contrast to the efficient market theory, the empirical evidence shows that this phenomenon is widespread in all （or most of） the countries of the world. This work examines the long-run performance in M＆As. For this purpose, 40 bidders were observed in Italy during the period of 1994-2008 among listed companies. The buy and hold abnormal returns （BHARs） methodology was used, with which it was possible to observe the returns for three years following the deal.

媒体报道如何影响并购重组知情交易:合流还是监督?

媒体报道既可能发挥积极的外部监督作用制约知情交易,也可能受到操纵而被信息知情人利用。本文收集2009—2022年A股上市公司并购重组数据,检验事前媒体负面报道倾向对并购重组中知情交易程度的影响。研究结果表明,并购重组首次公告日前媒体负面报道倾向越高,知情交易程度越低;媒体会通过增加诉讼风险和声誉渠道发挥治理作用。进一步分析表明,良好的公司治理环境能够强化媒体负面报道倾向对知情交易的影响;媒体发挥的治理功能在国有企业中相对较弱。事前分析师预测会提升市场整体知情交易水平并弱化媒体的功能。从媒体类型来看,网络媒体对于知情交易的约束作用大于纸媒。此外,媒体对知情交易的抑制效果在480日后不再存在。本研究对于发挥媒体监督作用、提升知情交易监管效率、保护投资者合法利益、维护资本市场公平具有一定的借鉴意义。

资本市场开放对企业并购融资的影响研究——基于“陆港通”多期双重差分的经验证据

“陆港通”政策是中国资本市场开放的重要举措。利用这一外生事件,以2010—2019年中国沪深A股并购事件为样本,运用多期双重差分模型检验“陆港通”对企业并购融资的影响,研究结果表明:“陆港通”实施可以降低并购的股权融资成本和债务融资成本,扩大并购的外部融资规模,缓解并购的融资约束程度,并且这种作用在非多元化和非关联企业并购中更加显著。进一步地探究“陆港通”对并购融资的影响机制,可以发现该政策通过改善信息环境和加强治理效应两种途径缓解企业的并购融资问题。因此,并购企业应积极响应“陆港通”政策,从而引入更多成熟的境外投资者,达到提高并购效率、提升并购效果的目的。

2023年全球油气资源并购市场特点及前景展望

2023年,全球油气资源并购交易总数量仅为201宗,基本达到20年内最低水平;但并购交易总金额超过2335亿美元,创下自2012年以来的最高值。2023年世界油气并购市场总体呈现4个方面的特点:一是北美地区交易金额创历史新高,俄罗斯-中亚地区交易数量接近历史最低值;二是各类国际石油公司并购金额整体增加,国际石油巨头发起多宗“超级并购”;三是并购交易的评价油价创2014年来新高,与国际油价走势差异明显;四是北美地区非常规资产并购活动保持活跃,页岩油相关资产交易金额创历史新高。展望2024年,预计油气资源并购交易市场活跃程度将持续提升,国际石油公司将着手优化“并购后”资产组合,国家石油公司或将加大上游资产购买力度。

基于ReliefF算法的钛合金电弧增材沉积层尺寸与光谱特性的相关性分析

电弧增材制造具有沉积效率高、成本低、沉积形状和尺寸不受限制等优点,而目前电弧增材制造成型件的成型精度难以精确保证。沉积层尺寸作为评价构件成型质量的标准之一,对判断加工质量以及缺陷补偿至关重要。实时监测电弧增材制造过程中沉积层尺寸的变化状态,对于优化工艺参数,确保增材制造构件的成型质量具有重要意义。电弧光谱信息可以反映电弧状态,电弧状态与成型质量密切相关,因此研究电弧光谱与沉积层尺寸的关系具有重要意义。以钛合金(TC4)材料作为基板和焊丝,电弧等离子体光谱信号为研究对象,研究GTAW增材电弧光谱特性与沉积层尺寸的相关性。搭建光谱采集系统,采集熔池上方、熔池外围、钨极下方不同位置的电弧光谱信号。基于谱线分离性高原则,分别选取波长为404.20 nm的TiⅠ谱线、波长为416.36 nm的TiⅡ谱线、波长为420.20、434.81、480.50和487.98 nm的ArⅡ谱线以及波长为696.54和794.82 nm的ArⅠ谱线,提取其谱线的峰强特征,结合ReliefF算法分别挖掘不同谱线强度特征与沉积层尺寸的相关性。结果表明,三组位置的所有谱线中熔池上方的波长为404.03 nm的TiⅠ元素谱线、416.36 nm的TiⅡ元素谱线以及794.82 nm的ArⅠ元素谱线谱峰强度特征与沉积层尺寸具有较强的相关性。分别研究相同位置的不同谱线峰强特征与沉积层尺寸的相关性差异,结果表明熔池上方与沉积层尺寸相关性最大特征谱线为波长696.54 nm的ArⅠ谱线、熔池外围和钨极下方与沉积层尺寸相关性最大的特征谱线为波长794.82的ArⅠ谱线。为减小随机误差,采用PCA算法将三个电弧光谱采集位置上与沉积层尺寸相关性最大的谱线对应的强度特征进行融合,获得新的融合特征,结合K近邻算法建立沉积层尺寸预测模型,分别计算这四个特征预测样本类别的准确率,发现融合特征预测样本所属的沉积层尺寸的准确率更高。基于此新特征结合阈值分割法实现动态监测沉积层尺寸变化。

数字技术并购对企业创新的影响研究

在数字经济蓬勃发展的趋势下,技术并购成为企业数字化转型的重要途径。文章基于2007—2021年中国A股上市公司数据,利用三重差分法探究数字技术并购对企业创新的影响。研究发现,数字技术并购能够显著促进企业创新,并且研发资源挤入效应、知识溢出效应和市场规模效应是三个重要的作用渠道。异质性分析表明,当主并企业所属行业竞争激烈、所在地区知识溢出便利,主并企业属于劳动密集型,目标企业为大型或科技型企业时,数字技术并购的创新促进作用更明显。此外,数字技术并购能够显著促进目标数字企业创新,当其规模较大、处于成长期或为科技型企业时,促进作用更明显。研究结论为企业数字化转型路径选择和数字经济政策设计实现“创新双赢”提供启示。

撤乡并镇后四川省乡镇卫生院医疗服务投入产出效率变化分析

目的:分析撤乡并镇后四川省乡镇卫生院医疗服务投入产出效率变化情况,为助力乡村医疗卫生体系健康发展提供参考依据。方法:以2018~2022年四川省5个样本市州48个区县为决策单元,采用BCC模型和Malmquist指数模型进行静态与动态效率分析。结果:2018~2022年样本市州乡镇卫生院机构数累计减少37.8%,院均床位数、职工人数、设备台数与医疗服务量累计增长率在49.8%~93.9%之间。医疗服务投入产出综合效率、技术效率和规模效率均值分别由2018年的0.800、0.843和0.950,变化为2022年的0.766、0.796和0.961。2018~2022年全要素生产率指数、技术进步指数和技术效率指均值分别为0.986、1.003和0.983。与2018年相比,2022年DEA无效区县数增加、减少和不变的市州数分别有2个、2个和1个。全要素生产率指数>1的区县数占比依次为成都62.5%、攀枝花40.0%、南充33.3%、阿坝23.1%和内江20.0%。结论:撤乡并镇后,四川省乡镇卫生院“小、散、弱”问题有效缓解,医疗服务投入产出规模效率有所提升;综合效率未见明显改善,技术效率下降是其主要原因;效率变化地区间差异明显。建议做好撤乡并镇改革“后半篇”文章,继续深化和拓展改革成果,以提升医疗技术水平和管理能力为关键点,区分不同地区共性与个性问题,多措并举推动乡镇卫生院量变成果转变为质变效果。

基于多层优选卷积的水声信号样本自动标注方法

针对深度学习在水声研究领域的应用中面临大数据量要求和现有样本量限制的问题,本文提出了一种多层优选卷积网络模型。通过基于相似度的优选方法选出最佳卷积核,以提取更具代表性的特征。利用探索层特征融合策略,叠加多层卷积输出,获取更全面的特征信息。采用约减策略优化模型,有效缩短运算时间。通过优选、特征融合和注意力机制,有效解决此类问题。实验结果表明,该模型在数据集上取得的最好的标注准确率为高基线模型1.12%;同时运行时间减少了43.5%。因此,该模型的使用提高了水声信号标注的准确率和效率。

数字贸易如何影响企业跨国并购

数字贸易逐渐发展成为中国建设贸易强国的新引擎,在促进企业对外投资等方面表现出了强劲的活力。基于2008—2022年中国A股上市公司相关数据,采用Probit模型,实证分析了数字贸易发展与企业跨国并购的关系。研究结果表明,数字贸易的发展能够推动企业跨国并购,并且这一结论在一系列稳健性检验后仍成立;异质性分析结果表明,数字贸易的发展更有利于推动大规模企业、主板上市企业、非两职合一企业及处于成熟期和衰退期的企业进行跨国并购,且对位于中西部地区及市场化程度较低地区的企业跨国并购促进作用更强;机制检验结果表明,数字贸易的发展能够通过促进企业创新水平的提高,降低企业的融资约束水平来促进企业跨国并购。