This thesis follows and analyses what happens to individuals who work at establishments that are closed down. I examine if and when the displaced workers are re-employed. Furthermore, I examine to what extent individuals have moved, changed industry of work, have started to commute or have become self-employed. Additionally I examine, if the workers become selfemployed after displacement, how many of them that does so within the same industry of work as they initially got displaced from. A unique longitudinal matched employer-employee data incorporating all firms, establishments and their employees in Sweden between the years 1997-2008 is used. All individuals between 25 and 55 years of age at the time of displacement that were displaced between 2000 and 2003 due to establishment closures are followed over a five-year period of time. Consistent with previous empirical research, it is shown that an absolute majority of the workers that are displaced one given year also recovers within that same year. The results moreover express that the longer the displaced workers are out of employment, the larger is the willingness to change industry of work, change municipality of living or move into self-employment. The willingness to commute is however found to be fairly constant over time. Finally, I find that those who become self-employed to a greater extent start business in other industries than they were displaced from as time passes.

El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / Mining in Peru has existed for several decades, and for several years, there has been no proper environmental management of the impact of this activity on the environment and society in general, whether it be gas emissions, the presence of acidic water, or the generation of mining tailings. One of the most prominent examples involve mine tailings; these are by-products of mining processing plants and are stored in a dam known as a tailings dam. Like any extraction activity, mining generates large amounts of waste material that could become potential risks to the environment and society. Using hydraulic fills, the mine tailings contained in tailings dams could be reused. These fills seek to decrease the volume of stored tailings to prevent any future dam collapses, as observed in Brazil with the Vale mining company, where its tailings dam collapsed and caused more than 200 deaths.

El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / Based on the review of different research studies, we could assess that, due to their unique biological features, microbes, specifically bacteria, could be used to repair damaged soils with heavy metal and toxic compound contents. Furthermore, these microorganisms are metabolically capable to oxidize cyanide and its by-products to generate less-toxic compounds at the end of the process. This research proposal seeks to improve conventional mine closure designs, thus counteracting their negative short-term, medium-term, and long-term after-effects to the environment. The proposed technique as a solution, therefore, is microbial remediation, using pseudomonas fluorescens bacteria to oxidize this compound to non-toxic components. It will ensure operational continuity for the deposits and, in turn, the sustainability of the entire mining industry.

<div> This dissertation is based on joint work with Lindsey Hill. There are two main parts, which are linked by the common theme of the integral closure of the Rees algebra.</div><div> </div><div> In the first part of this dissertation, comprised of Chapter 3 and Chapter 4, we study the integral closure of the Rees algebra directly. In Chapter 3 we identify a bound for the multiplicity of the Rees algebra R[It] of a homogeneous ideal I generated in the same degree, and combine this result with theorems of Ulrich and Vasconcelos to obtain upper bounds on the number of generators of the integral closure of the Rees algebra as a module over R[It]. We also find various other upper bounds for this number, and compare them in the case of a monomial ideal generated in the same degree. In Chapter 4, inspired by the large depth assumption on the integral closure of R[It] in the results of Chapter 3, we obtain a lower bound for the depth of the associated graded ring and the Rees algebra of the integral closure filtration in terms of the dimension of the Cohen-Macaulay local ring R and the equimultiple ideal I. We finish the first part of this dissertation with a characterization of when the integral closure of R[It] is Cohen-Macaulay for height 2 ideals. </div><div> </div><div> In the second part of this dissertation, Chapter 5, we use the integral closure of the Rees algebra as a tool to discuss specialization of the integral closure of an ideal I. We prove that for ideals of height at least two in a large class of rings, the integral closure of I is compatible with specialization modulo general elements of I. This result is analogous to a result of Itoh and an extension by Hong and Ulrich which show that for ideals of height at least two in a large class of rings, the integral closure of I is compatible with specialization modulo generic elements of I. We then discuss specialization modulo a general element of the maximal ideal, rather than modulo a general element of the ideal I itself. In general it is not the case that the operations of integral closure and specialization modulo a general element of the maximal ideal are compatible, even under the assumptions of our main theorem. We prove that the two operations are compatible for local excellent algebras over fields of characteristic zero whenever R/I is reduced with depth at least 2, and conclude with a class of ideals for which the two operations appear to be compatible based on computations in Macaulay2.</div>

Let G = (V, E) be a nontrivial connected graph. For a subset S ⊆ V, the geodesic closure (S) of S is the set of all vertices on geodesics (shortest paths) between two vertices of S. We study the geodetic achievement and avoidance games defined by Buckley and Harary (Geodetic games for graphs, Quaestiones Math. 8 (1986), 321–334) as follows. The first player A chooses a vertex v1 of G. The second player B then selects v2 ≠ v1 and determines the geodetic closure (S 2) for S 2 = {v 1 , v 2 }. If (S 2) = V, then the second player wins the achievement game, but loses the avoidance game. If (S 2) = V, then A picks v 3 ∉ S 2 and determines (S 3) for S 3 = {v 1 , v 2 , v 3 }. In general, A and B alternatively select a new vertex in this manner. The first player who selects a vertex v k such that (S k) = V wins the achievement game; in the avoidance game he is the loser. We solve these games for several families of graphs, including trees and complete multipartite graphs, by determining which player is the winner.

Background: Post-myocardial infarction (MI) ventricular septal defects (PIVSD) are an uncommon but life-threatening complication of acute MI. Although surgical closure has been the standard of care, mortality, and recurrence of VSD remain high even after emergent surgery. Transcatheter VSD closure (TCC) devices have become an alternative or adjunct to surgical closure. Methods: Online database search was performed for studies that included adults with PIVSD who underwent medical treatment (MT) alone, surgical closure (SC) (early or late), and TCC (early, late, or for post-surgical residual VSD). Results: Twenty-six studies were included with a total of 737 patients who underwent either MT (N = 100), SC (early (n = 167), late (n = 100)), and TCC (early (n = 176), late (n = 115), or post-surgical residual VSD (n = 79)). The 30-day mortality among MT group was 92 ± 6.3%, among SC was 61 ± 22.5% (early 56 ± 23%, late 41 ± 30%), and for all TCC patients was 33 ± 24% (early 54 ± 32.7%, late 16 ± 26%), and TCC for post-surgical residual VSD 11 ± 34.9%. The mortality among overall SC, overall TCC and early TCC groups was significantly lower as compared with the MT (P < 0.001 for all comparisons). The overall mortality among all TCC, and late TCC groups was significantly lower when compared with the late SC (P < 0.0001, P < 0.0001, respectively). Conclusion: Closure of PIVSD decreases mortality as compared with MT alone and should be attempted as early as possible after diagnosis. Selection of TCC versus SC should be based on factors including complexity of the defect, availability of closure devices, expertise of the operator, and clinical condition of patient.

A lot of mine were left abandoned, unrehabilitated or unclosed prior to the introduction National Environmental management Act 107 of 1998 and most did not have plans for rehabilitation or mine closure. The law requires that no exploration or production operations may commence unless financial provision has been made that is guaranteeing the availability of sufficient fund. planning is a prerequisite in the early development planning phase and must continue throughout the mine life cycle and closure phase. The financial provisions must be maintained for the duration of the life of the mine until closure when the closure certificate is issued. The financial provision is critical in ensuring that environmental liabilities for rehabilitation and closure are addressed. The purpose thereof is to mitigate the negative impacts of mining operations on the environment. This paper will investigate financial provisions system which is currently in use in South Africa from the financial security methods employed, the setting up, determination, quantification as well as general rules applicable thereto. The surveys undertaken in this regard and records held by the DMR will be relied on. When mine operations stop, a closure certificate must be issued to serve as proof that the plans relating to reclamation and closure have been complied with. The effect of a closure certificate exonerates the holder of such right from any residual or latent environmental liabilities. The paper will further look into the reasons and barriers to proper mine closure. The overall SA legislative framework for environmental liability relating to closure and rehabilitation generally conforms with international expectations. This paper examines the principal legislation and in particular the 2015 proposed regulations for securing financial provision for environmental liabilities. The main objectives of the research were to evaluate whether the current financial provision systems are appropriate in guaranteeing mine rehabilitation and closure. Moreover, whether they can realistically alter the legacy inherited from past abandoned or unclosed mines. Lastly, examination of the correlation between closure certificate and financial provision in relation to mine closure. Findings indicate that money set aside as financial provision for environmental liabilities is not being spent by the state. The law is clear which steps mine companies must take for rehabilitation and closure of new and old mine sites including legacy abandoned sites. The law is only as good as its implementation and enforcement. The Success of any financial surety instrument depends on the care, effort put into setting it up, managing it and meticulous calculation. Most will work if they are done properly. / Mini Dissertation (LLM)--University of Pretoria, 2019. / Public Law / LLM / Unrestricted

A titanium alloy (Ti-6Al-4V STOA) plate material was provided by the University of Dayton Research Institute from a previous U.S. Air Force high-cycle fatigue study. Fatigue-crack-growth tests on compact, C(T), specimens have been previously performed at Mississippi State University on the same material over a wide range in rates from threshold to near fracture for several load ratios (R = Pmin/Pmax). These tests used the compression pre-cracking method to generate fatigue-crack-growth-rate data in the near-threshold regime. Current load-reduction procedures were found to give elevated thresholds compared to compression pre-cracking methods. A crack-closure model was then used to determine crackront constraint and a plasticity-corrected effective stress-intensityactor-range relation over a wide range in rates and load ratios. Some engineering estimates were made for extremely slow rates (small-crack behavior), below the commonly defined threshold rate. Single-edge-notch-bend, SEN(B), fatigue specimens were machined from titanium alloy plates and were fatigue tested at two constant-amplitude load ratios (R = 0.1 and 0.5) and a modified Cold-Turbistan engine spectrum. Calculated fatigue lives from FASTRAN, a fatigue-life-prediction code, using small-crack theory with an equivalent-initiallaw-size (semi-circular surface flaw) of 9 µm in radius at the center of the semi-circular edge notch fit the constant-amplitude test data fairly well, but underpredicted the spectrum loading results by about a factor of 2 to 3. Life predictions made with linear-cumulative damage (LCD) calculations agreed fairly well with the spectrum tests.

The COVID-19 pandemic caused severe disruption to students worldwide, especially younger ones. This instrumental case study investigated how elementary students in a rural United States southeastern community experienced the sudden, extended closure of their school building facilities triggered by this health emergency. Multiple stakeholder perspectives were gathered through semi-structured interviews with the elementary school principal, three classroom teachers, three elementary-aged students, and three student family members, along with classroom observations as well as corresponding documents and artifacts. Interview commentaries and weekly reflective commentary journal entries were employed to address data validation and reliability issues. The findings demonstrate how the rural elementary school community leveraged its unique strengths (e.g., partnership with families, communal leaders, businesses, and local institutions) and overcame disadvantages under emergency conditions. Salutary lessons drawn from the COVID-19 extended school facilities closure were shared from the perspectives of the rural school stakeholders.

Sequences are sufficient to describe topological properties in metric spaces or, more generally, topological spaces having a countable base for the topology. However, filters or nets are needed in more abstract spaces. Nets are more natural extension of sequences but are generally less friendly to work with since quite often two nets have distinct directed sets for domains. Operations involving filters are set theoretic and generally certain to filters on the same set. The concept of a filter was introduced by H. Cartan in 1937 and an excellent treatment of the subject can be found in N. Bourbaki (1940).