165 research outputs found

    Essays on corruption, allocative inefficiency, and mergers and acquisitions

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    The aim of this thesis is to unearth, for developing countries, how investment climate constraints – i.e., electricity supply and corruption – affect firms’ performances and the misallocation of production inputs (i.e., capital and labour); as well as the efficacy of tax incentives in attracting inward investments in the form of mergers and acquisitions (M&As). The first chapter assesses the implication of electricity shortages on the allocative efficiency (or misallocation) of capital and labour for a sample of 750 Ghanaian manufacturing firms spanning the period 2011–2015. The motivation for and relevance of this empirical inquest stems from insights from nascent literature (Restuccia and Rogerson 2008; Banerjee and Duflo 2005; Hsieh and Klenow 2009) that demonstrate how allocative inefficiency of production inputs contributes to the low aggregate total factor productivity (TFP) in developing countries. The study’s findings suggest that when faced with unreliable and insufficient power supply, firms respond by curtailing the employment of capital, labour, and compensation (wages) to the latter. Additionally, electricity shortages appear to inhibit firms’ efficiency (TFP) performance. What is more, electricity shortages are found to also increase the misallocation of or the allocative inefficiency of capital and labour. This effect is more pronounced for firms that own generators implying that for these set of firms, which are also those most likely more reliant on electricity, self-generation is not sufficient to attenuate the adverse effects of insufficient and unreliable power supply from the national grid. The last set of results indicate that, particularly for the misallocation of capital, this effect is more pronounced for firms that are electricity constrained. A finding which leads to the conclusion that these group of firms have capital or production techniques that are more electricity reliant. The second chapter investigates the impact of tax incentives on inward foreign investments in the form of mergers and acquisitions (M&As) for a sample of 91 developing countries. Although the extant literature (Hines, 1996; Devereux and Griffith, 1998; Bénassy-Quéré, Fontagné and Lahrèche-Révil, 2005; Huizinga and Voget, 2009) evidentially informs us about the sensitivity of firm location decision or FDI to taxation particularly for advanced countries, little is known about the efficacy of conditional (or targeted) tax incentives in inducing foreign investors, particularly for developing countries. This study uncovers that concessionary tax rates have the tendency to attract inward M&As into developing countries. This finding is found to be more pronounced for concessionary tax rates that are geared towards or conditional on investors locating in a specific location or SEZs or contributing to domestic exporting activities. Unimpressively, the quantitative magnitudes are rather modest in that, for instance, a developing country will have to reduce tax rates by as much as 1.6% in order to attract a single inward M&A. The last (third) chapter uses firm-level data from the World Bank’s Enterprise Surveys to examine the economic consequences of corruption on the performances of firms in Africa. The novelty of this chapter stems from the fact that most studies (Aidt 2009; P. G. Méon and Weill 2010; Méndez and Sepúlveda 2006; Mauro 1995) that have probed this issue have been macro-based hence failing to unearth any micro insights, and the only micro-based study (Fisman and Svensson 2007) was undertaken for a cross-section of Ugandan firms. The results suggest that firms that are likely to be more established – i.e., older and larger firms – are less likely to engage in bribery payment, rather it is the least productive ones that are more likely to do so. The chapter’s findings further reveal that corruption has both a contemporaneous and lag effect on firm performances in Africa. Finally, the results confirm that this negative effect is more pronounced for larger and older firms than small and medium-sized firms and young firms

    CFD Port Flow Simulation of Air Flow Rate in Spark Ignition Engine

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    In the early stages of development of internal combustion engine (ICE), limitations such as speed, range, and lifespan led to series of researches resulting in the reduction or elimination of these limitations. Combustion in ICE is a rapid and controlled endothermic reaction between air in oxygen and fuel which is accompanied by significant increase in temperature and pressure with the production of heat, flame and carbon particle deposits. This combustion process is a phenomenon that involves turbulence, loss of air-fuel mixture during inflow and outflow into the cylinder. The objection of this study is to perform port flow analysis on ICE to determine flow rate and swirl at different valve lift under stationary engine parts.Methodology employed to analyze and solve the ICE port flow simulation is the use of CFD software that uses the finite volume method of numerical analysis to solve the continuity, Navier-Stokes and energy equations governing the air medium in the internal combustion engine cylinder. The model geometry for the analysis was generated using the Ansys Design Modeller for one cylinder, one suction port and one exhaust port, and two valves. The domain considered is internal combustion engine suction port with 86741 nodes and 263155 elements. Study results revealed that air mass was more concentrated around the valve and inlet port cross-section with swirling motion seen, air stream experienced turbulence as it flowed downwards inside the cylinder, air stream spread was turbulent which will eventually enhance smooth combustion, swirling air stream moves towards the cylinder wall where it experienced tumbling and turbulent which will eventually enhance smooth combustion. From the simulation it was revealed that mass flow rate of inlet air increases with valve lift

    Leiomyosarcomas of Vascular Origin in the Extremity

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    Between 1996 and 2006 a total of 278 patients with soft tissue Leiomyosarcoma were treated at our centre. We identified 16 patients (5.8%) where the tumour directly arose from the blood vessels. These tumours were studied to determine their prognosis and behaviour. All tumors were in the lower limbs: 11 from the femoral vein, 3 popliteal vein, and 2 from the posterior tibial vein. Mean tumour size was 10.4 cm (3 to 33). Histological grade was high in all patients. Surgical treatment was amputation in one, excision with or without vascular reconstruction in 12 followed by radiotherapy, and 3 patients had no surgery because of advanced disease at diagnosis. Seven out of the 16 patients (44%) had metastasis at diagnosis, and five patients without metastasis at diagnosis rapidly developed metastases at a median time of 5 months from diagnosis (2–30 months). The overall survival of the patients at 5 years was 25% which was considerably worse than those with nonvascular leiomyosarcoma. We conclude that patients with leiomyosarcoma of vascular origin have a very high risk of metastases and poor prognosis when treated in the conventional way

    Chondroblastoma of bone in extremities. - A single centre study of 177 cases

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    Introduction Chondroblastoma is a rare benign bone tumour that usually occurs in children and young adults. They are cartilaginous tumours arising in the epiphysis or apophysis of a long bone. The tumour is classified as benign, although rare cases of pulmonary metastases have been reported. The aims of this study were to describe clinical, radiographic characteristics of chondroblastoma; to analyse the local recurrence rate and complications associated with surgery. Material and methods This retrospective study included 177 patients, who had been diagnosed with a chondroblastoma in extremity between 1990 and 2015. Results The most common site was proximal tibia 20%, followed by proximal humerus 19%, proximal femur 18%, distal femur 16% and foot 15%. One patient has died of the disease and one patient is alive after being operated for lung metastases. There was local recurrence in 25/177 (14%) patients. The median time to local recurrence was 10 months (range 3-158 months). The most common site for local recurrence was proximal tibia (22.2%). The proximal femur was the location in 32/178 (18%) of the cases. 18/32 (56%) were in the greater trochanter and 14/32 (44%) in the femoral head. The mean age was lower in tumours located in femoral head when compared to the greater trochanter; 19.5 years and 13.9 years respectively (p=0.004). Tumours located in greater trochanter were all curetted without further complications. Local recurrence was seen more often in femoral head tumours, though without statistical significance; 3/14 (21%) and none, respectively (p=0.073). Conclusions Chondroblastoma is a rare benign to intermediate grade bone tumour with a potential to metastasise. Femoral head chondroblastoma is rare, presenting 4.5% of all chondroblastoma cases. Around 50% of the chondroblastoma in femoral head. occur in patients with open growth plates.Peer reviewe

    ‘‘Two-Week Waits”—Are They Leading to Earlier Diagnosis of Soft-Tissue Sarcomas?

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    Introduction. The ‘‘two-week wait” was established as a potential means of diagnosing malignant tumours earlier. This paper investigated whether these clinics are leading to earlier diagnosis of malignant soft-tissue lumps. Method. We identified all referrals to our centre from a database over a 4-year period. Results. 2225 patients were referred to our unit for investigation of a soft-tissue mass. 576 (26%) were referred under the ‘‘two-week wait” criteria. 153 (27%) of which were found to have a malignant or borderline malignant diagnosis. 1649 patients were referred nonurgently. 855 (52%) of which were diagnosed with a malignant or borderline lesion. The average size at diagnosis was 9.4 cm with no difference in size between the different referral routes. Conclusion. There is little evidence that the two-week wait clinic is leading to earlier diagnosis of soft-tissue sarcomas with the majority still being referred nonurgently

    Primary Leiomyosarcoma of Bone: Analysis of Prognosis

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    Leiomyosarcoma of bone is just one of the variants of spindle cell sarcoma of bone characterised by the expression of desmin and other markers indicating a significant element of smooth muscle in the tumour, without osteoid production we have investigated the management and outcome of this rare type of primary malignant bone tumour. Method. Retrospective review of data stored on a prospective database. Results. In a database of 3364 patients with primary malignant bone sarcomas, 31 patients were identified with a primary leiomyosarcoma of bone. There were 12 males and 19 females with a mean age of 46 and tumour size of 8 cm. The most common site was the distal femur followed by the proximal tibia. Treatment was with chemotherapy and surgical resection. Seven of the patients had metastases at diagnosis. Surgery was carried out in 28 patients, 8 having amputation and 20 limb salvage. Three patients developed local recurrence, but half developed metastases. All patient disease-specific survival was 57% at five years and 44% at 10 yrs but for those without metastases was 82% and 60%, respectively. The only prognostic factors were metastases at diagnosis. Conclusion. Leiomyosarcoma of bone is a very rare primary malignant bone tumour affecting a predominantly older population. Despite the high incidence of metastases, survival is better than for other bone sarcomas for those without metastases at diagnosis

    Elastofibroma Dorsi: An Uncommon Benign Pseudotumour

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    Elastofibroma dorsi is an uncommon benign soft tissue pseudotumour usually located at the lower pole of the scapula, deep to serratus anterior, and often attached to the periosteum of the ribs, presenting with long history of swelling and occasionally pain and discomfort. This lesion is usually seen in patients over the age of 50 years and is not uncommonly mistaken as a malignant tumour because of its size and location deep to the periscapular muscles. Review of the orthopaedic oncology database of 17 500 patients revealed that there were 15 patients with elastofibroma dorsi. There were 12 males and 3 females, mean age at diagnosis of 68.4 years range 51–79 years. The diagnosis was confirmed by MRI in 3 patients, excision biopsy in 3 patients, trucut biopsy in 8 patients and open biopsy in 1 patient. Eight patients had excision of the lesion which was symptomatic. There have been no recurrences. We highlight the clinical and radiological presentation of elastofibroma dorsi to increase awareness of its existence and management

    Mobile laminar air flow screen for additional operating room ventilation: reduction of intraoperative bacterial contamination during total knee arthroplasty

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    Background Surgical site infections are important complications in orthopedic surgery. A mobile laminar air flow (LAF) screen could represent a useful addition to an operating room (OR) with conventional turbulent air ventilation (12.5 air changes/h), as it could decrease the bacterial count near the operating field. The purpose of this study was to evaluate LAF efficacy at reducing bacterial contamination in the surgical area during 34 total knee arthroplasties (TKAs). Materials and methods The additional unit was used in 17 operations; the LAF was positioned beside the operating table between two of the surgeons, with the air flow directed towards the surgical area (wound). The whole team wore conventional OR clothing and the correct hygiene procedures and rituals were used. Bacterial air contamination (CFU/m3) was evaluated in the wound area in 17 operations with the LAF unit and 17 without the LAF unit. Results The LAF unit reduced the mean bacterial count in the wound area from 23.5 CFU/m3 without the LAF to 3.5 CFU/m3 with the LAF (P<0.0001), which is below the suggested limit for anORwith ultraclean laminar ventilation. There were no significant differences in the mean bacterial count in the instrument table area: 28.6 CFU/m3 were recorded with the LAF (N = 6) unit and 30.8 CFU/m3 (N = 6) without the LAF unit (P = 0.631). During six operations with LAF and six without LAF, particle counts were performed and the number of 0.5 lm particles was analyzed. The particle counts decreased significantly when the LAF unit was used (P = 0.003). Conclusion When a mobile LAF unit was added to the standard OR ventilation, bacterial contamination of the wound area significantly decreased to below the accepted level for an ultraclean OR, preventing SSI infections
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