Essays on accounting conservatism, corporate social responsibility, and corporate governance

This thesis consists of three essays on accounting conservatism, corporate social responsibility, and corporate governance. The first essay examines the influence of accounting conservatism on trade credit, particularly under the background of the recent global financial crisis. The second essay investigates whether suppliers value customer firms’ corporate social responsibility activities by exploring the influence of customer firms’ social performance on trade credit. The third essay examines how the heterogeneous credit crunch shock that took place during the recent global financial crisis moderated the effectiveness of corporate governance on deterring expropriation by controlling shareholders and improving firm performance.Accounting conservatism and trade credit / Yanlei Zhang. -- Do suppliers value socially responsible customers / Yanlei Zhang, Juan M. García Lara and Josep A. Tribó. -- Heterogeneous credit crunch shock and the effectiveness os corporate governance / Yanlei Zhang, María GutiérrezPrograma Oficial de Doctorado en Empresa y Finanzas / Business and FinancePresidente: Miguel Ángel García Cestona; Secretario: Beatriz García Osma; Vocal: Juan Pedro Sánchez Ballest

Simulation of Grid-connected Wind Generator in Wind Power Flow Optimization System Experiment Platform

AbstractA simulation system of grid-connected wind power generator used for research and development of wind power flow optimization system is analysed and designed. It's key component parts, connection structure and working principle are introduced. As a core module, the DC/AC power condition system (DAPCS) is emphatically discussed and described with respect to topology, modeling and control strategy. Experimental results indicate that the simulated wind power generator can output fluctuant power meeting the demand of research and develop of wind power flow optimization system

Bubble Flow Analysis of High Speed Cylindrical Roller Bearing under Fluid-Solid Thermal Coupling

Heat generation model of high speed cylindrical roller bearing is constructed by calculating the local friction in the bearing. Bubble flow calculation model of roller bearing considering fluid-solid thermal coupling is constructed based on two-body fluid model and k-ε turbulent model, in which diameter and size of bubbles, breakup, and coalescence model of bubbles are considered. Using dynamic mesh method, a new method for evaluating bearing temperature is set up treating the rolling elements as moving heat sources. Based on these models and finite element method, bubble flow of a high speed roller bearing is studied based on FLUENT software. The numerical study reveals the relationship between velocity of bearing, air volume fraction, and velocity and pressure of oil-air flow. An increase of air content in the oil produces a lower pressure at the bearing outlet while the exit fluid velocity increases. When fluid-solid thermal coupling effect is considered, velocity and pressure at outlet of the bearing both become larger, while temperature of bearing is lower than that without coupling. In comparison, the coupling effects on flow pressure and temperature are obvious. For a given rotating speed, there is an optimal value for air volume fraction, such that temperature rise of the bearing reaches the lowest value. Experiments verify the outcomes of the method presented in this paper

Positive solutions for second-order differential equations with singularities and separated integral boundary conditions

We study the existence of positive solutions for second-order differential equations with separated integral boundary conditions. The nonlinear part of the equation involves the derivative and may be singular for the second and third space variables. The result ensures existence of a positive solution when the parameters are in certain ranges. The proof depends on general properties of the associated Green’s function and the Krasnosel’skii–Guo fixed point theorem applied to a perturbed Hammerstein integral operator. Both numerical and analytical examples are constructed to illustrate applications of the theorem to a group of equations. The result generalizes previous work

Health Economics and Outcome Studies on Type 2 Diabetes Education and Screening in a Chinese Population

Type 2 diabetes occurs as a consequence of aging, family history, physical inactivity, unhealthy diet and obesity and it is an increasing public health problem worldwide. The condition is associated with high rates of mortality from co-morbid cardiovascular diseases and poor health-related quality of life (HRQoL). A large proportion of individuals with type 2 diabetes are not diagnosed for up to a decade after onset unless a screening programme has been implemented. The estimated prevalence of undiagnosed diabetes in China accounts for about 60-70% of the diabetes population. Diabetes education that is targeted at the general population is the key to increase public knowledge and awareness and is a fundamental building block for addressing the diabetes epidemic. Screening for identifying undiagnosed diabetes could lead to earlier identification and intervention, and postpone or prevent the onset of diabetes and its complications. However, there is a paucity of study on the impact of education and screening programmes on HRQoL, lifestyle modification of the targeted population, and the cost-effectiveness of such programmes. The objectives of this study were to investigate 1) the cost and effectiveness of a population-based education programme to increase public knowledge and awareness of diabetes; 2) the cost-effectiveness of two different screening tools for undiagnosed diabetes; 3) impact of type 2 diabetes and its complications on individuals HRQoL; 4) impact of a screening programme on individuals overall HRQoL, depression dimension and lifestyle modification. This study was based on data analyses of two population-based diabetes surveys conducted in 2006 (Survey A) and 2009 (Survey C), and a dataset of diabetes high-risk population identified through the Qingdao Diabetes Prevention Program (QD-DPP) between 2007 and 2010 in Qingdao, China (Survey B). The same stratified, random cluster sampling method was used in Surveys A and C to recruit a representative sample of the general population who had lived in Qingdao city for at least five years. A total of 5355 individuals in Survey A and 5110 in Survey C aged 35-74 years participated in the surveys. A total of 3108 rural participants who did not have diabetes at baseline in 2009 were invited for a re-examination and 1782 individuals attended the follow-up survey. A standard 2h 75g oral glucose tolerance test was administrated to all participants in both surveys. Diabetes education and health promotion information and activities under the framework of QD-DPP were given via printed and audio-visual media, the internet, free distribution of information booklets and diabetes risk score (DRS) flyers that targeted the entire population of 1.94 million who lived in the intervention areas. An adult with a DRS more or as much as 14 was considered at high-risk for diabetes and invited to a nearby community clinic for a free capillary blood glucose test. The proportions of participants who correctly marked obesity, physical inactivity and positive family history of diabetes as the risk factors of diabetes were doubled in both urban and rural populations, irrespective of age and gender during the QD-DPP education campaign period. The cheapest way to inform 1000 individuals about type 2 diabetes was to distribute DRS flyers (¥54, ¥ = Chinese yuan), followed by the newspapers articles (¥77), booklets (¥313) and by radio programmes (¥375) (1 ≈7¥, for the year 2015). The fasting capillary glucose (FCG) test and Chinese DRS questionnaire were used as the first-line screening tools and these were evaluated for detecting undiagnosed diabetes in primary care settings. The sensitivity of FCG and DRS was 65.1% and 65.8%, whereas their respective specificity was 72.4% and 55.2%. The costs per undiagnosed diabetes identified at the optimal cut-off values of 6.1 mmol/l for FCG and 14 for DRS were ¥674 and ¥844, respectively. The area under curve (AUC) was higher for FCG than for DRS (75.3% vs. 63.7%, p less than 0.001). People with previously known type 2 diabetes reported that the symptomatic comorbidities had a strong negative impact on HRQoL; no significant difference was detected between people without diabetes and with newly diagnosed diabetes. The screening and labelling as pre-diabetes or normoglycaemia had no adverse impact on the participants overall HRQoL and depression. An improvement in lifestyle as measured by the frequency of physical activity and vegetable intake was observed at 3 years post screening in both groups. In conclusion, the QD-DPP education campaign efficiently increased public knowledge and awareness of diabetes. The DRS questionnaire is a simple, non-invasive and reliable first-line screening tool to identify undiagnosed diabetes at primary care settings. The diabetes screening programme in Qingdao generated positive changes towards a healthy lifestyle and did not result in any harm to the participants.Tyypin 2 diabetes on kasvava kansanterveysongelma maailmanlaajuisesti. Syitä ovat ikääntyminen, perhehistoria, fyysisen liikunnan puute, epäterveellinen ruokavalio ja lihavuus. Tautiin liittyy huono terveyteen liittyvä elämänlaatu ja korkea kuolleisuus liitännäisiin sydän- ja verisuonisairauksiin. Suurta osaa henkilöistä, joilla on tyypin 2 diabetes, ei diagnosoida jopa vuosikymmeneen ilman seulontaohjelmaa. Kiinassa diagosoimattoman diabeteksen osuus on noin 60-70%. Väestölle suunnattu diabetesopetus on avainasemassa, kun halutaan lisätä tietoa ja tietoisuutta taudista ja rakentaa perustaa diabetesepidemian vastustukseen. Seulonta diagnosoimattoman diabeteksen löytämiseksi voisi johtaa varhaisempaan interventioon sekä diabeteksen ja sen komplikaatioiden puhkeamisen siirtämiseen tai ehkäisyyn. Koulutus- ja seulontaohjelmien vaikutusta kohdeväestön terveyteen liittyvään elämänlaatuun ja elämäntyylin muutokseen sekä sellaisten ohjelmien kustannusvaikuttavuutta on kuitenkin tutkittu vähän. Tämän tutkimuksen tavoitteena oli selvittää Kiinassa 1) väestön diabetestiedon ja tietoisuuden lisäämiseen tähtäävän väestön opetusohjelman kustannuksia ja kustannusvaikuttavuutta; 2) diagnosoimattoman diabeteksen kahden erilaisen seulontaohjelman kustannusvaikuttavuutta; 3) tyypin 2 diabeteksen ja sen komplikaatioiden vaikutusta ihmisten terveyteen liittyvään elämänlaatuun 15D:llä mitattuna; 4) seulontaohjelman vaikutusta ihmisten terveyteen liittyvään elämänlaatuun, masennukseen ja elämäntyylin muutokseen. Tämä tutkimus perustuu kahteen diabetesta koskevaan väestökyselyyn, jotka toteutettiin vuonna 2006 (kysely A) ja 2009 (kysely C), sekä aineistoon diabeteksen suhteen korkeariskisestä väestöstä, mikä tunnistettiin vuosien 2007 ja 2010 välillä Qingdaon diabeteksen ehkäisyohjelman (Qingdao Diabetes Prevention Program, QD-DPP) (kysely B) avulla Qingdaossa, Kiinassa. Kyselyissä A ja C käytettiin samaa ositettua ja satunnaistettua ryväsotantaa, jolla otettiin edustava otos väestöstä, joka oli asunut Qingdaon kaupungissa ainakin viisi vuotta. Kaikkiaan 5355 henkeä, iältään 35-74 vuotta, osallistui kyselyyn A ja 5110 kyselyyn C. Kaikkiaan 3108 maaseudun asukasta, joilla ei ollut diabetesta lähtötilanteessa vuonna 2009, kutsuttiin uusintatutkimukseen ja 1782 henkeä osallistui seurantakyselyyn. Kaikille molempien kyselyiden osallistujille tehtiin standardi 2 tunnin 75g:n suullinen sokerirasitustesti. QD-DPP:ssa toteutettiin diabetesopetusta ja terveyden edistämistä käyttämällä painettua ja audiovisuaalista viestintää, internetiä, sekä jakamalla maksutta informaatiolehtisiä ja diabeteksen riskilukeman (diabetes risk score, DRS) esitteitä interventioalueiden koko 1.94 miljoonan kohdeväestölle. Aikuisilla, joilla DRS enemmän tai yhtä paljon kuin 14, katsottiin olevan korkea diabetesriski ja heidät kutsuttiin läheiseen terveyskeskukseen maksuttomaan verensokeritestiin. QD-DPP:n opetuskampanjan aikana kaksinkertaistui ikään ja sukupuoleen katsomatta sekä maaseudulla että kaupungissa niiden osallistujien osuus, jotka merkitsivät oikein lihavuuden, fyysisen liikunnan puutteen ja diabeteksen perhehistorian diabeteksen riskitekijöiksi. Halvin tapa opettaa 1000 henkilöä oli jakaa DRS-esitteitä (¥54, ¥ = CNY = kiinan yuan, vaihtokurssi EUR 1 = CNY 7.1396, elokuun 14, 2015), seuraavina olivat sanomalehdet (¥77), informaatiolehtiset (¥313) ja radio-ohjelma (¥375). Paastosokeritesti (Fasting capillary glucose, FCG) ja kiinalainen DRS-kyselylomake arvioitiin ensilinjan seulontamenetelminä etsittäessä diagnosoimatonta diabetesta perusterveydenhuollossa. FCG:n ja DRS:n herkkyys oli 65.1 % and 65.8 %, tarkkuus 72.4 % and 55.2 %, ja kustannus löydettyä diagnosoimatonta diabetesta kohti ¥674 ja ¥844, mainitussa järjestyksessä, kun optimaaliset raja-arvot olivat 6.1 mmol/l FCG:lle ja 14 DRS:lle. Pinta-ala käyrän alla (area under curve, AUC) oli suurempi FCG:lla kuin DRS:lla (75.3 % vs. 63.7 %, p vähemmän kuin 0.001). Ihmiset, joilla oli aiemmin todettu tyypin 2 diabetes, ilmoittivat oireellisia oheissairauksia ja niillä oli vahva negatiivinen vaikutus 15D:llä mitattuun terveyteen liittyvään elämänlaatuun; tilastollisesti merkitsevää eroa ei havaittu niiden välillä, joilla ei ollut diabetesta ja joilla oli äskettäin diagnosoitu diabetes. Seulonnan perusteella todetulla esidiabeteksella tai normaalilla verensokeritasolla ei ollut vaikutusta terveyteen liittyvään elämänlaatuun tai masennukseen. Fyysisen liikunnan useudella ja vihannesten syönnillä mitatussa elämäntyylissä havaittiin molemmissa ryhmissä parannus kolme vuotta seulonnan jälkeen. Johtopäätöksenä voidaan todeta, että QD-DPP:n opetuskampanja lisäsi tehokkaasti väestön diabetestietoa ja -tietoisuutta. DRS-kyselylomake on yksinkertainen, kajoamaton ja luotettava ensilinjan seulontamenetelmä diagnosoimattoman diabeteksen löytämiseksi perusterveydenhuollossa. Diabeteksen ehkäisyohjelma Qingdaossa sai aikaan positiivisia muutoksia kohti terveellistä elämäntyyliä eikä aiheuttanut haittaa osallistujille

Unpacking the black box of trade credit to socially responsible customers

We investigate whether suppliers value customer firms’ socially responsible activities by examining the relation between corporate social responsibility (CSR) and firms’ access to trade credit. We posit that firms with better social performance are more likely to receive trade credit because suppliers view customers’ CSR activities as a signal of trustworthiness and of the capacity to meet financial obligations. In addition to this direct channel, we describe other channels: a) trade credit opens the possibility for suppliers to secure a share of their customers’ future business opportunities, which are expected to be higher for socially responsible firms, and b) the risk associated with the diffusion of negative shocks through the supply chain due to trade credit is lower for socially responsible firms, making them more attractive partners for suppliers. Consistent with our predictions, we find that socially responsible customers receive more trade credit from suppliers. This relation is more pronounced in situations where the aforementioned channels are more relevant: namely, when the financial health of a customer is of greater importance to its suppliers; when there are greater information asymmetries between suppliers and customers due to a lack of close transactional relationships; when socially responsible activities are more likely to generate growth; and when suppliers are exposed to higher risk in the customer-supplier relationship. We also document that during the global financial crisis, socially responsible customers offered backward liquidity provision to suppliers by reducing their use of trade credit, which represents an extra benefit of having socially responsible customers in production networks.We acknowledge financial support from the Spanish Ministry of Economy and Competitiveness (ECO2012-36559, ECO2015-68715-R-MINECO/FEDER, PGC2018-097187-B-I00, ECO2013-48328, ECO2016-77579 and WRDS-UC3M: Infrastructure for large scale data processing, FEDER UNC315-EE-3636), from a Comunidad de Madrid grant (EARLYFIN-CM, #S2015/HUM-3353), from Copenhagen Business School and from the EU's European Social Fund

Current advances of photobiomodulation therapy in treating knee osteoarthritis

Knee osteoarthritis (KOA) is manifested by low-grade joint inflammation, irreversible cartilage degeneration, subchondral bone remodeling and osteophyte formation. It is one of the most prevalent degenerative diseases in the elderly. KOA usually results in chronic joint pain, physical impairment even disability bringing a huge socioeconomic burden. Unfortunately, there is so far no effective interventions to delay the progression and development of KOA. There is a pressing need for explorations and developments of new effective interventions. Photobiomodulation therapy (PBMT), also known as low-level light therapy (LLLT), has attracted widespread attention in treating KOA because it is drug-free, non-invasive, safe and useful with rarely reported side effects. It provides the biological stimulatory effects primarily by enhancing the activity of mitochondrial cytochrome c oxidase. This stimulation, in turn, fosters cell proliferation and tissue regeneration. In addition to this, the paper provides a concise overview of the light parameters and the effectiveness of PBMT when applied in the treatment of KOA patients in clinical settings. It also delves into the experimental evidence supporting the modulatory effects of PBMT and its potential underlying mechanisms in addressing synovitis, cartilage degeneration, and pain resolution

Recognition Technology for Four Arithmetic Operations

Numeral recognition is an important research direction in field of pattern recognition, and it has broad application prospects. Aiming at four arithmetic operations of general printed formats, this article adopts a multiple hybrid recognition method and is applied to automatically calculating. This method mainly uses BP neural network and template matching method to distinguish the numerals and operators, in order to increase the operation speed and recognition accuracy. Sample images of four arithmetic operations are extracted from printed books, and they are used for testing the performance of proposed recognition method. The experiments show that the method provides correct recognition rate of 96% and correct calculation rate of 89%

Effect of specimen thicknesses on water absorption and flexural strength of CFRP laminates subjected to water or alkaline solution immersion

In this paper, an experimental research was undertaken to investigate the effect of specimen thicknesses on water absorptions and flexural strengths of wet lay-up CFRP laminates subjected to distilled water or alkaline solution immersion up to 180 days. Test results showed that the water uptake and flexural strength retention of CFRP laminates were significantly affected by the adopted specimen thickness. For the same aging time, the water uptake of CFRP laminates decreased in the early stage of immersion and increased in the later stage of immersion with the increase of specimen thickness. Meanwhile, the flexural strength retention generally increased as specimen thickness increased. In addition, a new thickness-based accelerated method for hygrothermal aging test of CFRP laminates was proposed. The accelerated factors of the water uptake and flexural strength retention of CFRP laminates were theoretically deduced. The proposed analytical model of accelerated factors was verified with current test data, and then applied to predict long-term properties of CFRP laminates. Compared with the traditional temperature-based accelerated method, the new thickness-based accelerated method is much easier to apply to predict long-term properties of CFRP laminates with good accuracy