Does Mergers and Acquisition Improve Performance?

Merger and acquisition is an important way for companies to expand market share, obtain greater market power and set up new disciplines. Generally, people believe that merger and acquisition would bring benefit from the acquirer as the managers of acquirers are assumed make rational decisions. However, previous studies have shown that acquirers may not benefit from merger. Researchers conduct studies on merger performance from various prospective in order to explain the post merger performance of the target or acquirer. For example, some of them focus on the relationship between the payment method and merger performance. Some of them focus on the industry relevance while some may believe the initial share in target may affect post merger performance. In this dissertation, we are going to analysis the merger performance in a different way. We will use event study method to find out the relationship between the merger performance and the way of merger, takeover and tender offer

Does Mergers and Acquisition Improve Performance?

Merger and acquisition is an important way for companies to expand market share, obtain greater market power and set up new disciplines. Generally, people believe that merger and acquisition would bring benefit from the acquirer as the managers of acquirers are assumed make rational decisions. However, previous studies have shown that acquirers may not benefit from merger. Researchers conduct studies on merger performance from various prospective in order to explain the post merger performance of the target or acquirer. For example, some of them focus on the relationship between the payment method and merger performance. Some of them focus on the industry relevance while some may believe the initial share in target may affect post merger performance. In this dissertation, we are going to analysis the merger performance in a different way. We will use event study method to find out the relationship between the merger performance and the way of merger, takeover and tender offer

Time-delay signature suppression in delayed-feedback semiconductor lasers as a paradigm for feedback control in complex physiological networks

Physiological phenomena are often accompanied by time delay effects which may lead to oscillatory and even chaotic dynamics in their behaviors. Analogous dynamics is found in semiconductor lasers subject to delayed optical feedback where the dynamics typically includes a signature of the time delay. In many applications of semiconductor lasers, the suppression of the time delay signature is essential for applications and hence several approaches have been adopted for that purpose. In this paper experimental results are presented wherein photonic filters are utilized in order to suppress time-delay signatures in semiconductor lasers subject to delayed optical feedback effects. Two kinds of semiconductor lasers are used: discrete mode semiconductor lasers and vertical-cavity surfaceemitting lasers (VCSELs). It is shown that, by the use of photonic filters, complete suppression of the time-delay signature may be affected in discrete mode semiconductor lasers but that a remnant of the signature persists for VCSEL

DFT-Spread Spectrally Overlapped Hybrid OFDM-Digital Filter Multiple Access IMDD PONs

A novel transmission technique—namely, a DFT-spread spectrally overlapped hybrid OFDM–digital filter multiple access (DFMA) PON based on intensity modulation and direct detection (IMDD)—is here proposed by employing the discrete Fourier transform (DFT)-spread technique in each optical network unit (ONU) and the optical line terminal (OLT). Detailed numerical simulations are carried out to identify optimal ONU transceiver parameters and explore their maximum achievable upstream transmission performances on the IMDD PON systems. The results show that the DFT-spread technique in the proposed PON is effective in enhancing the upstream transmission performance to its maximum potential, whilst still maintaining all of the salient features associated with previously reported PONs. Compared with previously reported PONs excluding DFT-spread, a significant peak-to-average power ratio (PAPR) reduction of over 2 dB is achieved, leading to a 1 dB reduction in the optimal signal clipping ratio (CR). As a direct consequence of the PAPR reduction, the proposed PON has excellent tolerance to reduced digital-to-analogue converter/analogue-to-digital converter (DAC/ADC) bit resolution, and can therefore ensure the utilization of a minimum DAC/ADC resolution of only 6 bits at the forward error correction (FEC) limit (1 × 10−3). In addition, the proposed PON can improve the upstream power budget by >1.4 dB and increase the aggregate upstream signal transmission rate by up to 10% without degrading nonlinearity tolerances

Microwave photonic signal generation in an optically injected discrete mode semiconductor laser

This article belongs to the Special Issue Microwave Photonics Applications.In this paper, microwave photonic signal generation based on the period-one dynamic of optically injected discrete mode (DM) semiconductor lasers has been experimentally demonstrated and numerically simulated. The results show that the frequency of the generated microwave increases linearly with the frequency detuning or optical injection ratio. In addition, a single optical feedback loop is sufficient to reduce the microwave linewidth without significantly deteriorating side mode suppression. The simulation results using a model considering the nonlinear dependencies of the carrier recombination agree well with the experimental results, which indicates that the nonlinear carrier recombination effect is important in determining the nonlinear dynamics of optically injected DM lasers.This research was funded in part by the DESTINI project (2017/COL/007) funded by the ERDF under the SMART Expertise scheme; in part by the DSP Centre (82085) funded by the ERDF through the Welsh Government; and in part by Ministerio de Ciencia e Innovación, Spain, under grant RTI2018-094118-B-C22 MCIN/AEI/FEDER, UE.Peer reviewe

Reversible splenial lesion syndrome in children: a retrospective study of 130 cases

BackgroundReversible splenial lesion syndrome (RESLES) is a new clinico-radiological syndrome. We retrospectively analyzed the clinical features of 130 children with RESLES in China, which is the largest case series available in the literature.MethodsThe clinical data of children diagnosed as RESLES in Jiangxi Provincial Children's Hospital between 2017 and 2023 were retrospectively analyzed. The 130 cases were divided into two groups: ≤ 3 years old group (group A) (n = 83) and > 3 years old group (group B) (n = 47). The chi-squared test or Fisher's test was used to evaluate the data.ResultsThe vast majority of patients (127/130 cases, 97.7%) had prodromal symptoms of infection. Preceding infections of the gastrointestinal tract were statistically more significant in group A (60/83, 72.3%) than in group B (11/47, 23.4%) (P < 0.05). Preceding infections of the respiratory tract were statistically more significant in group B (33/47, 70.2%) than in group A (17/83, 20.5%) (P < 0.05). Seizures were statistically more significant in group A (82/83, 98.8%) than in group B (24/47,51.1%) (P < 0.05). The disturbance of consciousness and headache/dizziness were statistically more significant in group B (27/47, 57.4%; 37/47, 78.7%) than in group A (3/83, 3.6%; 1/83, 1.2%), respectively (P < 0.05). Convulsions with mild gastroenteritis (CwG) were statistically more significant in group A (50/83, 60.2%) than in group B (8/47, 17.0%) (P < 0.05). However, encephalitis/encephalopathy was statistically more significant in group B (20/47, 42.6%) than in group A (10/83, 12.0%) (P < 0.05). MRI showed cytotoxic edema in typical locations (RESLES type-1 limited to the splenium of the corpus callosum and RESLES type-2 spread to the entire corpus callosum, adjacent white matter, or both). There was full recovery of the lesions of MRI in all cases from 3 days to 50 days after the initial examinations. All the children showed normal neurodevelopment.ConclusionInfection was the most common cause of RESLES. Infections of the gastrointestinal tract are common in ≤ 3 years old children, while infections of the respiratory tract are common in >3 years old children. Younger patients are more likely to develop convulsions, and older children were more likely to have symptoms with disturbance of consciousness and headache/dizziness. RESLES has characteristic MRI manifestations and a good prognosis