Extreme Secular Excitation of Eccentricity Inside Mean Motion Resonance: Driving Small Bodies into Star-Grazing Orbits by Planetary Perturbations

It is well known that asteroids and comets fall into the Sun. Metal pollution of white dwarfs and transient spectroscopic signatures of young stars like $\beta$-Pic provide growing evidence that extra solar planetesimals can attain extreme orbital eccentricities and fall onto their parent stars. We aim to develop a general, practically implementable, semi-analytical theory of secular eccentricity excitation of small bodies in mean motion resonances with an eccentric planet valid for arbitrary values of the eccentricities and including the short-range force due to General Relativity. Our semi-analytic model for the restricted planar three-body problem does not make use of any series expansion and therefore is valid for any values of eccentricities and semi-major axes ratios. The model is based on the application of the adiabatic principle, which is valid when the precession period of the longitude of pericenter of the planetesimal is much longer than the libration period in the mean motion resonance. This holds down to vanishingly small eccentricities in resonances of order larger than 1. We provide a Mathematica notebook with the implementation of the model allowing direct use to the interested reader. We confirm that the 4:1 mean motion resonance with a moderately eccentric planet is the most powerful one to lift the eccentricity of planetesimals from nearly circular orbits to star-grazing ones. However, if the planet is too eccentric, we find that this resonances becomes unable to pump the planetesimal's eccentricity to very high value. The inclusion of the General Relativity effect imposes a condition on the mass of the planet to drive the planetsimals into star-grazing orbits. For a planetesimal at $\sim$1 AU around a solar-mass star (or white dwarf), we find a threshold planetary mass of about 17 Earth masses. We finally derive an analytical formula for this critical mass.Comment: In press in Astronomy & Astrophysic

Accounting historians engaging with scholars inside and outside accounting: issues, opportunities and obstacles

Originating in a panel presentation at the eighth Accounting History International Conference, this study offers a reflection on the issues, opportunities and obstacles which may arise when accounting historians engage with other accounting scholars and scholars outside of accounting. Supporting the view that accounting scholars need and should make an effort to engage with other scholars inside and outside accounting, various aspects are considered as enhancing the interdisciplinarity of accounting history research. Then, issues such as researchers and the community, research problems, theories, methods and data are addressed. The opportunities arising from interdisciplinary interactions with a wide range of scholars are then developed. Finally, the potential obstacles are addressed. These obstacles can be overcome by the development of robust communication and the invention of a new genre of discourse and research focus and by working with those outside our discipline and embracing the challenge of the new and the different

Mitigating aerosol infection risk in school buildings: the role of natural ventilation, volume, occupancy and CO2 monitoring

Issues linked to aerosol physics within school buildings and related infection risk still lack a proper recognition in school safety regulations. Limited spaces and limited available window-surfaces require to precisely investigate the seasonal airing factors and the occupancy/volume ratios in each classroom in order to assess the specific risk levels from viral loads of potentially infective sources. Moreover, most schools are still not provided with mechanical HVAC systems nor with air quality sensors. Fundamental questions are therefore: how the specific classroom volume and the specific airing cycle affects the long-range contagion risk in a given classroom? is linear social distancing the right way to assess a volumetric risk problem? We present here the results of an extended quantitative analysis based on the GN-Riley infection risk model applied to a real classroom scenario. The study discusses seasonality of the airing flow and the effectiveness of single and combined mitigation interventions, such as limiting student groups, equipping teachers with microphones, increasing classroom volumes, and equipping classrooms with CO2 sensors to safely drive airing intervals. Moreover, we show experimental CO2 concentrations as well as occupancy and airing factors monitored in real time in a real classroom scenario. In agreement with recent literature, the results emphasize the need for a dynamic evaluation of the complex risk function over the whole exposure time (and not just the monitoring of the istanteneous CO2 concentration) in order to correctly control the infection risk from aerosolization

What does materiality mean to integrated reporting preparers? An empirical exploration

Purpose—This paper seeks to understand how the principle of materiality gets implemented in integrated reporting contexts. Design/methodology/approach—Drawing on an interpretation of materiality as a social construction, this research explores the meaning that practitioners attach to the principle during their implementation of it. Following an existing framework for exploring materiality in corporate reporting, this study investigates the meaning by focusing on who participates in determining integrated reporting materiality and to whom the integrated report (IR) is addressed. This analysis benefits from in-depth interviews with persons involved in the preparation of IR for a firm that pioneered this form of reporting. Findings—In IR preparers’ view, the meaning of materiality corresponds with the company strategy: The IR describes strategic priorities and related actions and results. Capital providers are the primary intended addressees of the material information. Although several actors engage in IR preparation, the materiality determination process is governed by a specific “IR hub” in strict collaboration with and dependence on the CFO. Research limitations/implications—In an IR context, materiality is intimately connected to the function that preparers assign to the report. Originality/value—This novel research opens the “black box” of the process by which materiality gets defined and then practically implemented in an IR context

Integrated reporting and narrative accountability: the role of preparers

Purpose: The International Integrated Reporting Council claims that integrated reporting (IR) can enhance corporate accountability, yet critical and interpretative studies have contested this outcome. Insufficient empirical research details how preparers experience accountability while constructing IR; to fill this gap, the purpose of this paper is to analyse how the preparers’ mode of cognition influences the patterns of accountability associated with IR. Design/methodology/approach: A functionalist approach to narratives helps elucidate the role that the IR preparers’ narrative mode of cognition plays on accountability towards stakeholders. The empirical analysis particularly benefits from in-depth interviews with the IR preparers of a global insurer that has used IR since 2013. Findings: The preparers’ narrative mode of cognition facilitates dialogue with IR users. It addresses accountability tensions by revealing the company’s value creation process. Preparers’ efforts to establish a meaningful dialogue with a growing variety of stakeholders through broader and plainer messages reveals the potential of IR as a narrative source of a socializing form of accountability. However, financial stakeholders remain the primary addressees of the reports. Research limitations/implications: This paper focusses on preparers’ views; further research should integrate users’ accountability expectations. Originality/value: This paper offers new insights for dealing with corporate reporting and accountability in a novel IR setting

Loss of Renal Function After Retrograde Ureteral Placement of an Allium Stent for Severe Ureteral Stricture

Background: Ureteral strictures are a recurrent chronic condition that leads to severe side effects and poor quality of life. Management of ureteral stricture is a great challenge for urologists and no specific guidelines exist. Retrograde Allium®ureteral stent (AUS) is a newly developed ureteral stent to treat either bulbar urethral or ureteral stenosis. Case Presentation: We describe a case of a 74-year-old Caucasian adult male presenting with a severe ureteral stricture secondary to an ureteroscopy for stone disease. Treatment with retrograde AUS placement produced a complete loss of renal function after 36 months, probably because of the development of a long achalasic stretch of the ureter. Conclusions: AUS is a new and promising device for the treatment of ureteral stenosis. However, a lack of standardization of the technique recommends a close instrumental follow-up after the procedure to decide the optimal time for stent removal

Total Parathyroidectomy with Subcutaneous Parathyroid Forearm Autotransplantation in the Treatment of Secondary Hyperparathyroidism: A Single-Center Experience.

Abstract Introduction Secondary hyperparathyroidism is common in chronic kidney disease. Parathyroidectomy is indicated in refractory hyperparathyroidism when medical treatments and so the parathyroid hormone levels cannot be lowered to acceptable values without causing significant hyperphosphatemia or hypercalcemia. The aim of this study is to compare the efficacy and safety of total parathyroidectomy with subcutaneous forearm autotransplantation with total parathyroidectomy with intramuscular forearm autotransplantation. Materials and Methods A single-center retrospective cohort study of total parathyroidectomy with forearm autotransplantation from January 2002 to February 2013 was performed. According to the surgical technique, patients were divided into an intramuscular group (Group 1) and a subcutaneous group (Group 2). 38 patients with secondary hyperparathyroidism were enrolled; 23 patients were subjected to total parathyroidectomy with parathyroid tissue replanting in the subcutaneous forearm of the upper nondominant limb, while 15 patients were subjected to replanting in the intramuscular seat. Results A total of 38 patients (56 ± 13 years) were enrolled. In both groups, the preoperative iPTH value was markedly high, 1750 ± 619 pg/ml in the intramuscular autotransplantation group and 1527 ± 451 pg/ml in the subcutaneous autotransplantation group (p = 0.079). Transient hypoparathyroidism was shown in 7 patients, and 1 patient showed persistent hypoparathyroidism (p = 0.387). 2 patients showed persistent hyperparathyroidism (p = 0.816), and in 2 others was found recurrent hyperparathyroidism (p = 0.816); 3 of them underwent autograftectomy. The anterior compartment of the forearm nondominant limb was sacrificed in 1 case of intramuscular autotransplantation with functional arm deficit. Conclusions The efficacy and safety of parathyroid tissue autotransplantation in the subcutaneous forearm of the upper nondominant limb is confirmed with a good rate of tissue engraftment and with a comparable number of postsurgical transient and persistent hypoparathyroidism and hyperparathyroidism incidence in both techniques. Furthermore, this technique preserves arm functionality in the case of autograftectomy. Consequently, it is our opinion that total parathyroidectomy with subcutaneous forearm autotransplantation is currently the best choice

Family firms and innovation: the role of ventured-start-ups

Technological innovation can be defined as the set of activities through which a firm conceives, designs, manufactures, and introduces a new product, technology, system or technique (Freeman, 1976). It can take place according to different strategies: through internal R&D and by mean of external knowledge acquisition (Cassiman and Veugelers, 2006). Extant studies are predominantly focused on the analysis of the \u201cinternal perspective\u201d, while there is a research gap on how firms can reach technological innovation by mean of venture capital initiatives (Dushnitsky and Lenox, 2005). The present paper aims to fill this gap by focusing on how family small and medium entities (SMEs) may develop technological innovations by creating ventured start-ups. In particular, considering the previous studies which identified the family firms\u2019 peculiar characteristics in terms of processes like corporate governance (Randoy and Goel, 2003), internationalization (Zahra, 2003), entrepreneurship (Naldi et al., 2007) and financing (Romano et al., 2001), the research investigates how the family firm\u2019s ownership structure affects its technological innovation activities and outcomes (Hoskisson et al., 2002)

Disclosing Business Model in the "Integrated Report": Evidence from European Early Adopters

The rising emphasis on the business model (BM) as a reportable element reflects the view it constitutes one of the key starting point for investors\u2019 analysis. In spite of this, recent academic and professional studies describe current reporting on BM as \u201cinadequate\u201d advancing the most heated critics for the presence of a so-called \u201cboilerplate\u201d disclosure.The IASB has thus embarked on a new initiative with the International Integrated Reporting Council to promote BM disclosure by mean of a particular reporting format called \u201cIntegrated Report\u201d (IR). An IR is as a clear and concise representation of how organization creates and sustains value, and BM constitutes a fundamental issue of disclosure. The paper aims to understand whether IR is apt to offer informative disclosure on firm\u2019s BM. Drawing on previous studies on voluntary disclosure, the paper purposes a \u201cframework of analysis\u201d to assess the quality of BM disclosure with specific regards to extensiveness and spread of covered topics and to three specific language attributes: type of information (quantitative vs. non-quantitative), tone (positive vs. non positive) and time orientation (forward looking vs. non-forward looking). By performing an in-depth manual content analysis, we apply our \u201cframework of analysis\u201d to all the European early-adopters and we find that their BM disclosure is substantially informative. Our findings have relevant implications in corroborating the role of IR project in improving reporting on BM

The governmentality of corporate (un)sustainability: the case of the ILVA steel plant in Taranto (Italy)

The present research aims to investigate the role of states in governing the sustain- ability trajectories and decisions of companies and their local communities. Draw- ing on Dean’s (Governmentality: power and rule in modern society, SAGE, London, 2009) “analytics of government” as the theoretical framework, the paper focuses on detecting how the Italian Government “problematised” the sustainability-related risks associated with the ILVA steel plant in Taranto, whose levels of pollution have worried both the Italian authorities and the European Union Commission. The anal- ysis also considers the “regimes of governance” under which the risks have been addressed and then explains the “utopian ideal” that the Italian Government tried to achieve by allowing the company to continue its activity, contrary to the Italian Judiciary’s provision to halt the hot working area of the steel plant in July 2012. Patterns related to Dean’s framework were identi ed through an iterative process of manual elaborative coding of the o cial documents ascribable to the main actors involved in governing the sustainability-related risks at ILVA. The ndings show that the Italian Government took its decisions on ILVA in the name of relevant risks of unemployment, economic development and territorial competitiveness. The Ital- ian Government adopted several practices of governance to make these risks more “visible” and to silence the environmental and health risks that, otherwise, would have emphasised the unsustainability of the business activities. The paper extends the growing body of research that investigates corporate (un)sustainability practices by showing how states may directly in uence sustainability-related corporate risks in the name of a higher public interest