Multi-scale approaches to Food Sciences: computational QM and MM explorations at the microscopic level

L'obiettivo principale della politica di sicurezza alimentare è quello di garantire la salute dei consumatori attraverso regole e protocolli di sicurezza specifici. Al fine di rispondere ai requisiti di sicurezza alimentare e standardizzazione della qualità, nel 2002 il Parlamento Europeo e il Consiglio dell'UE (Regolamento (CE) 178/2002 (CE, 2002)), hanno cercato di uniformare concetti, principi e procedure in modo da fornire una base comune in materia di disciplina degli alimenti e mangimi provenienti da Stati membri a livello comunitario. La formalizzazione di regole e protocolli di standardizzazione dovrebbe però passare attraverso una più dettagliata e accurata comprensione ed armonizzazione delle proprietà globali (macroscopiche), pseudo-locali (mesoscopiche), ed eventualmente, locali (microscopiche) dei prodotti alimentari. L'obiettivo principale di questa tesi di dottorato è di illustrare come le tecniche computazionali possano rappresentare un valido supporto per l'analisi e ciò tramite (i) l’applicazione di protocolli e (ii) miglioramento delle tecniche ampiamente applicate. Una dimostrazione diretta delle potenzialità già offerte dagli approcci computazionali viene offerta nel primo lavoro in cui un virtual screening basato su docking è stato applicato al fine di valutare la preliminare xeno-androgenicità di alcuni contaminanti alimentari. Il secondo e terzo lavoro riguardano lo sviluppo e la convalida di nuovi descrittori chimico-fisici in un contesto 3D-QSAR. Denominata HyPhar (Hydrophobic Pharmacophore), la nuova metodologia così messa a punto è stata usata per esplorare il tema della selettività tra bersagli molecolari strutturalmente correlati e ha così dimostrato di possedere i necessari requisiti di applicabilità e adattabilità in un contesto alimentare. Nel complesso, i risultati ci permettono di essere fiduciosi nel potenziale impatto che le tecniche in silico potranno avere nella identificazione e chiarificazione di eventi molecolari implicati negli aspetti tossicologici e nutrizionali degli alimenti.

Vulnerable and exploitable:the need for organisational accountability and transparency in emerging and less developed economies

The aim of this paper is to provide an overview of the papers which appear in this special issue of Accounting Forum. The paper sets out the background and rationale for this special issue, introduces the papers contained within it and discusses their contributions to the literature on social and environmental accounting and accountability in emerging and less developed economies. This discussion is informed by the notions of vulnerability and exploitability. The final section of the paper provides conclusions and directions for future research in this under-researched area. © 2013 Elsevier Ltd.

Dynamic joint sentiment-topic model

Social media data are produced continuously by a large and uncontrolled number of users. The dynamic nature of such data requires the sentiment and topic analysis model to be also dynamically updated, capturing the most recent language use of sentiments and topics in text. We propose a dynamic Joint Sentiment-Topic model (dJST) which allows the detection and tracking of views of current and recurrent interests and shifts in topic and sentiment. Both topic and sentiment dynamics are captured by assuming that the current sentiment-topic-specific word distributions are generated according to the word distributions at previous epochs. We study three different ways of accounting for such dependency information: (1) Sliding window where the current sentiment-topic word distributions are dependent on the previous sentiment-topic-specific word distributions in the last S epochs; (2) skip model where history sentiment topic word distributions are considered by skipping some epochs in between; and (3) multiscale model where previous long- and shorttimescale distributions are taken into consideration. We derive efficient online inference procedures to sequentially update the model with newly arrived data and show the effectiveness of our proposed model on the Mozilla add-on reviews crawled between 2007 and 2011. © 2013 ACM 2157-6904/2013/12-ART5 $ 15.00.

Pre-adoption market reaction to IFRS 9:a cross-country event-study

We are the first to examine the market reaction to 13 announcement dates related to IFRS 9 for over 5400 European listed firms. We find an overall positive reaction to the introduction of IFRS 9. The regulation is particularly beneficial to shareholders of firms in countries with weaker rule of law and a smaller divergence between local GAAP and IAS 39. Bootstrap simulations rule out the possibility that sampling error or data mining are driving our findings. Our main findings are also robust to confounding events and the extent of the media coverage for each event. These results suggest that investors perceive the new regulation as shareholder-wealth enhancing and support the view that stronger comparability across accounting standards of European firms is beneficial to international investors and outweighs the costs of poorer firm-specific information.

Developing Financial Expertise Through Mathematics and IT School Curricula

Report published in the Proceedings of the National Conference on "Education and Research in the Information Society", Plovdiv, May, 2014

Social and environmental accountability in developing countries

The principal aim of this chapter is to undertake a critical review of the social and environmental accountability of global business activities in developing countries. While global business activities have contributed to the economic development of developing countries they have many adverse social and environmental consequences which are often under-studied. I explore the role of accounting in making those consequences visible. The chapter, however, concludes that while social and environmental accounting has the potential to raise the visibility of social and environmental impacts of corporate activities it often fails to do so particularly under the current voluntary disclosure regime where corporations can choose what to report and how to report. This is even more pronounced in the developing countries because of their vulnerabilities arising from various social and environmental problems. The chapter argues for a case of ‘surrogate accountability’ as an alternative to the current corporate driven form of accountability.

Losses, dividend reductions, and market reaction associated with past earnings and dividends patterns

This paper examines investors' reactions to dividend reductions or omissions conditional on past earnings and dividend patterns for a sample of eighty-two U.S. firms that incurred an annual loss. We document that the market reaction for firms with long patterns of past earnings and dividend payouts is significantly more negative than for firms with lessestablished past earnings and dividends records. Our results can be explained by the following line of reasoning. First, consistent with DeAngelo, DeAngelo, and Skinner (1992), a loss following a long stream of earnings and dividend payments represents an unreliable indicator of future earnings. Thus, established firms have higher loss reliability than less-established firms. Second, because current earnings and dividend policy are a substitute source of means of forecasting future earnings, lower loss reliability increases the information content of dividend reductions. Therefore, given the presence of a loss, the longer the stream of prior earnings and dividend payments, (1) the lower the loss reliability and (2) the more reliably dividend cuts are perceived as an indication that earnings difficulties will persist in the future.

Internal control reporting by non-accelerated filers

I examine three issues related to internal control reporting by non-accelerated filers. Motivation for the three studies comes from the fact that Section 404 of the Sarbanes-Oxley Act (SOX) continues to be controversial, as evidenced by the permanent exemption from Section 404(b) of SOX granted to non-accelerated filers by the Dodd-Frank Wall Street Reform and Consumer Protection Act of 2010. The Dodd-Frank Act also requires the SEC to study compliance costs associated with smaller accelerated filers. In the first part of my dissertation, I document that the audit fee premium for non-accelerated filers disclosing a material weakness in internal controls (a) is significantly lower than the corresponding premium for accelerated filers, and (b) declines significantly over time. I also find that in the case of accelerated filers remediating clients pay lower fees compared to clients continuing to report internal control problems; however, such differences are not observed in the case of non-accelerated filers. The second essay focuses on audit report lag. The results indicate that presence of material weaknesses are associated with increased audit report lags, for both accelerated and non-accelerated filers. The results also indicate that the decline in report lag following remediation of problems is greater for accelerated filers than for non-accelerated filers. The third essay examines early warnings (pursuant to Section 302 disclosures) for firms that subsequently disclosed internal control problems in their 404 reports. The analyses indicate that non-accelerated firms with shorter CFO tenure, presence of accounting experts on the audit committee, and more frequent audit committee meetings are more likely to provide prior Section 302 warnings. Overall the results suggest that there are differences in internal control reporting between the accelerated and non-accelerated filers. The results provide empirical grounding for the ongoing debate about internal control reporting by non-accelerated filers.

Essays on audit report lag

Audit reporting lag continues to remain an issue of significant interest to regulators, financial statement users, public companies, and auditors. The SEC has recently acted to reduce the deadline for filing annual and quarterly financial statements. Such focus on audit reporting lag arises because, as noted by the Financial Accounting Standards Board, relevance and reliability are the two primary qualities of accounting information; and, to be relevant, information has to be timely. In my dissertation, I examine three issues related to the audit report lag. The first essay focuses on the association between audit report lag and the meeting or beating of earnings benchmarks. I do not find any association between audit report lag and just meeting or beating earnings benchmarks. However, I find that longer audit report lag is negatively associated with the probability of using discretionary accruals to meet or beat earnings benchmarks. We can infer from these results that audit effort, for which audit report lag is a proxy, reduces earnings management. The second part of my dissertation examines the association between types of auditor changes and audit report lag. I find that the resignation of an auditor is associated longer audit report lag compared to the dismissal of an auditor. I also find a significant positive association between the disclosure of a reportable event and audit report lag. The third part of my dissertation investigates the association between senior executive changes and audit report lag. I find that audit report lag is longer when client firms have a new CEO or CFO. Further, I find that audit report lag is longer when the new executive is someone from outside the firm. These results provide empirical evidence about the importance of senior management in the financial reporting process.

Universalização do acesso à saúde e regulação dos planos privados de assistência à saúde: a atuação regulatória da ANS como instrumento de harmonia contratual e viabilização do papel suplementar da iniciativa privada na efetivação do direito social à saúde

While essential to human nature, health and life have been protected since ancient times by various areas of knowledge, particularly by the Law, given its dynamics within the regulation of social interactions. In Brazil, health has been granted major importance by the Federal Constitution of 1988, which, disrupting the dictatorial authoritarianism, inaugurating a Social State and focusing on the values of freedom and human dignity, raises health to the condition of a social right, marked predominantly by an obligational bias directed, primarily, to the State, through the enforcement of public policies. Although, given the limitation of the State action to the reserve for contingencies, it turns clear that an universalizing access to public health is impossible, seen that the high cost of medical provisions hinders the State to meet all the health needs of the rightholders. As a result of the inefficiency of the State, the effort of the Constituent Assembly of 1988 in creating a hybrid health system becomes nuclear, which, marked by the possibility of exploration of healthcare by the private initiative, assigns to the private enterprise a key role in supplementing the public health system, especially through the offer of health insurance plans. At this point, however, it becomes clear that health provisions rendered by the private agents are not unlimited, which involves discussions about services and procedures that should be excluded from the contractual coverage, for purposes of sectoral balance, situation which draws the indispensability of deliberations between Fundamental Rights on one hand, related to the protection of health and life, and contractual principles on the other hand, connected to the primacy of private autonomy. At this point, the importance of the regulation undertaken by the ANS, Brazilian National Health Agency, appears primordial, which, by means of its seized broad functions, considerable autonomy and technical discretion, has conditions to implement an effective control towards the harmonization of the regulatory triangle, the stability and development of the supplementary health system and, consequently, towards the universalization of the right to health, within constitutional contours. According to this, the present essay, resorting to a broad legislative, doctrinal and jurisprudential study, concludes that economic regulation over the private healthcare sector, when legitimately undertaken, provides progress and stability to the intervening segment and, besides, turns healthcare universalization feasible, in a way that it can not be replaced efficiently by any other State function.

La recherche internationale en génétique et l’utilisation secondaire des données : entre dissociation et harmonisation

L’étude des polymorphismes et des aspects multifactoriels des déterminants de la santé suscite un engouement majeur envers la recherche populationnelle en génétique et génomique. Cette méthode de recherche requiert cependant la collecte et l’analyse d’un nombre élevé d’échantillons biologiques et de données associées, ce qui stimule le développement des biobanques. Ces biobanques, composées des données personnelles et de santé de milliers de participants, constituent désormais une ressource essentielle permettant l’étude de l’étiologie des maladies complexes et multifactorielles, tout en augmentant la rapidité et la fiabilité des résultats de recherche. Afin d’optimiser l’utilisation de ces ressources, les chercheurs combinent maintenant les informations contenues dans différentes biobanques de manière à créer virtuellement des mégacohortes de sujets. Cependant, tout partage de données à des fins de recherche internationale est dépendant de la possibilité, à la fois légale et éthique, d’utiliser ces données aux fins pressenties. Le droit d’utiliser les données personnelles, médicales et génétiques de participants dans le cadre de recherches internationales est soumis à un ensemble complexe et exhaustif d’exigences légales et éthiques. Cette complexité est exacerbée lorsque les participants sont décédés. Fondée sur une révision de l’interprétation individualiste du concept de consentement éclairé, ainsi qu’une perspective constructiviste des concepts de confiance et d’autonomie, cette thèse se situe au carrefour de la recherche, du droit et de l’éthique, et a pour objectif de proposer un modèle promouvant l’harmonisation éthique et juridique des données aux fins de recherches internationales en génétique.

Size-partitioned phytoplankton carbon concentrations retrieved from ocean color data, links to data in netCDF format

Owing to their important roles in biogeochemical cycles, phytoplankton functional types (PFTs) have been the aim of an increasing number of ocean color algorithms. Yet, none of the existing methods are based on phytoplankton carbon (C) biomass, which is a fundamental biogeochemical and ecological variable and the "unit of accounting" in Earth system models. We present a novel bio-optical algorithm to retrieve size-partitioned phytoplankton carbon from ocean color satellite data. The algorithm is based on existing methods to estimate particle volume from a power-law particle size distribution (PSD). Volume is converted to carbon concentrations using a compilation of allometric relationships. We quantify absolute and fractional biomass in three PFTs based on size - picophytoplankton (0.5-2 µm in diameter), nanophytoplankton (2-20 µm) and microphytoplankton (20-50 µm). The mean spatial distributions of total phytoplankton C biomass and individual PFTs, derived from global SeaWiFS monthly ocean color data, are consistent with current understanding of oceanic ecosystems, i.e., oligotrophic regions are characterized by low biomass and dominance of picoplankton, whereas eutrophic regions have high biomass to which nanoplankton and microplankton contribute relatively larger fractions. Global climatological, spatially integrated phytoplankton carbon biomass standing stock estimates using our PSD-based approach yield - 0.25 Gt of C, consistent with analogous estimates from two other ocean color algorithms and several state-of-the-art Earth system models. Satisfactory in situ closure observed between PSD and POC measurements lends support to the theoretical basis of the PSD-based algorithm. Uncertainty budget analyses indicate that absolute carbon concentration uncertainties are driven by the PSD parameter No which determines particle number concentration to first order, while uncertainties in PFTs' fractional contributions to total C biomass are mostly due to the allometric coefficients. The C algorithm presented here, which is not empirically constrained a priori, partitions biomass in size classes and introduces improvement over the assumptions of the other approaches. However, the range of phytoplankton C biomass spatial variability globally is larger than estimated by any other models considered here, which suggests an empirical correction to the No parameter is needed, based on PSD validation statistics. These corrected absolute carbon biomass concentrations validate well against in situ POC observations.

Future Earnings Growth Volatility and the Value Premium

The value premium is well established in empirical asset pricing, but to date there is little understanding as to its fundamental drivers. We use a stochastic earnings valuation model to establish a direct link between the volatility of future earnings growth and firm value. We illustrate that risky earnings growth affects growth and value firms differently. We provide empirical evidence that the volatility of future earnings growth is a significant determinant of the value premium. Using data on individual firms and characteristic-sorted test portfolios, we also find that earnings growth volatility is significant in explaining the cross-sectional variation of stock returns. Our findings imply that the value premium is the rational consequence of accounting for risky earnings growth in the firm valuation process.

Italian Ragweed Pollen Inventory

This study provides the first spatially detailed and complete inventory of Ambrosia pollen sources in Italy – the third largest centre of ragweed in Europe. The inventory relies on a well tested top-down approach that combines local knowledge, detailed land cover, pollen observations and a digital elevation model that assumes permanent ragweed populations mainly grow below 745m. The pollen data were obtained from 92 volumetric pollen traps located throughout Italy during 2004-2013. Land cover is derived from Corine Land cover information with 100m resolution. The digital elevation model is based on the NASA shuttle radar mission with 90m resolution. The inventory is produced using a combination of ArcGIS and Python for automation and validated using cross-correlation and has a final resolution of 5km x 5km. The method includes a harmonization of the inventory with other European inventories for the Pannonian Plain, France and Austria in order to provide a coherent picture of all major ragweed sources. The results show that the mean annual pollen index varies from 0 in South Italy to 6779 in the Po Valley. The results also show that very large pollen indexes are observed in the Milan region, but this region has smaller amounts of ragweed habitats compared to other parts of the Po Valley and known ragweed areas in France and the Pannonian Plain. A significant decrease in Ambrosia pollen concentrations was recorded in 2013 by pollen monitoring stations located in the Po Valley, particularly in the Northwest of Milan. This was the same year as the appearance of the Ophraella communa leaf beetle in Northern Italy. These results suggest that ragweed habitats near to the Milan region have very high densities of Ambrosia plants compared to other known ragweed habitats in Europe. The Milan region therefore appears to contain habitats with the largest ragweed infestation in Europe, but a smaller amount of habitats is a likely cause the pollen index to be lower compared to central parts of the Pannonian Plain. A low number of densely packed habitats may have increased the impact of the Ophraella beetle and might account for the documented decrease in airborne Ambrosia pollen levels, an event that cannot be explained by meteorology alone. Further investigations that model atmospheric pollen before and after the appearance of the beetle in this part of Northern Italy are needed to assess the influence of the beetle on airborne Ambrosia pollen concentrations. Future work will focus on short distance transport episodes for stations located in the Po Valley, and long distance transport events for stations in Central Italy that exhibit peaks in daily airborne Ambrosia pollen levels.

Le succès reproducteur au début de la vie, la longévité et le succès reproducteur tardif chez la femelle de la chèvre de montagne

La théorie biodémographique liée à l’âge prédit un compromis entre l’allocation reproductrice au début de la vie et la reproduction tardive, la survie, ou ces deux composantes de la valeur adaptative à la fois. Actuellement, la notion de compromis a été démontrée par plusieurs études en milieu naturel. Par contre, l’effet des conditions environnementales et de la qualité des individus a rarement été étudié. Grâce aux données longitudinales récoltées dans la population de chèvres de montagne (Oreamnos americanus) de Caw Ridge, Alberta, nous avons pu examiner l’influence de l’âge à la première reproduction (APR) et du succès reproducteur au début de la vie (SRD) sur la longévité et sur le succès reproducteur tardif, en tenant compte des conditions environnementales natales et de la qualité des individus. Contrairement à nos prédictions, nous n’avons pas détecté la présence d’un compromis entre l’allocation reproductrice au début de la vie et la performance tardive dans cette population. Au contraire, l’APR et le SRD avaient des effets directs et faiblement positifs sur le succès reproducteur tardif. La densité de population à la naissance d’une femelle a fortement réduit le succès reproducteur tardif de manière directe. Elle l’affectait également de manière indirecte par son effet sur l’APR et le SRD. La densité était le seul facteur déterminant de la longévité, par un effet direct et fortement négatif. Tel que démontré dans des études précédentes sur la même population, les femelles de bonne qualité avaient un SRD élevé par rapport aux femelles de mauvaise qualité. Ces résultats fournissent une vision intégrée des compromis au début et à la fin de la vie, en soulignant l’importance de tenir compte des conditions environnementales, qui pourraient engendrer des implications à long terme sur la dynamique des populations.