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This paper aims to study Irreversible conversion processes, which examine the spread of a one way change of state (from state 0 to state 1) through a specified society (the spread of disease through populations, the spread of opinion through social networks, etc.) where the conversion rule is determined at the beginning of the study. These processes can be modeled into graph theoretical models where the vertex set V(G) represents the set of individuals on which the conversion is spreading.

The irreversible k-threshold conversion process on a graph G=(V,E) is an iterative process which starts by choosing a set S_0?V, and for each step t (t = 1, 2,…,), S_t is obtained from S_(t−1) by adjoining all vertices that have at least k neighbors in S_(t−1). S_0 is called the seed set of the k-threshold conversion process and is called an irreversible k-threshold conversion set (IkCS) of G if S_t = V(G) for some t = 0. The minimum cardinality of all the IkCSs of G is referred to as the irreversible k-threshold conversion number of G and is denoted by C_k (G).

In this paper the authors determine C_k (G) for generalized Jahangir graph J_(s,m) for 1 < k = m and s, m are arbitraries. The authors also determine C_k (G) for strong grids P_2? P_n when k = 4, 5. Finally, the authors determine C_2 (G) for P_n? P_n when n is arbitrary.

This work is 100% original and has important use in real life problems like Anti-Bioterrorism.

This paper aims to examine the time it would take to provide medical prophylaxis for a large urban population in the wake of an airborne anthrax attack and the effect that various parameters have on the total logistical time.

A mathematical model that evaluates key parameters and suggests alternatives for improvement is formulated. The objective of the model is to minimize the total logistical time required for prophylaxis by balancing three cycles as follows: the loading cycle, the shipping cycle and the service cycle.

Applying the model to two representative cases reveals the effect of various parameters on the process. For example, the number of distribution centers and the number of servers in each center are key parameters, whereas the number of central depots and the local shipping method is less important.

Various psychological factors such as mass panic are not included in the model.

There are few papers analyzing the logistical response to an anthrax attack, and most focus mainly on the strategic level. The study deals with the tactical logistical level. The authors focus on the distribution process of prophylaxis and other medical supplies during the crisis, analyze it and identify the parameters that influence the time between the detection of the attack and the provision of effective medical treatment to the exposed population.

This study describes preparedness of emergency physicians and general practitioners following chemical, radiological and nuclear incidents.

Five emergency physicians and six general practitioners were interviewed individually, and data was analysed using qualitative content analysis.

The study results showed that physicians' preparedness for chemical, radiological and nuclear incidents is linked to one main category: to be an expert and to seek expertise and two categories: preparations before receiving CRN patients, and physical examination and treatment of CRN patients with subcategories.

The results have implications for further research on the complexity of generalist vs specialist competence and knowledge when responding to chemical, radiological and nuclear incidents.

This study provides insights regarding chemical, radiological and nuclear preparedness among physicians at emergency departments and primary healthcare centres.

The purpose of this paper is to examine evolution of the American strategy toward terrorism in the aftermath of the events of September 11, 2001. In other words, this study revolves around a key question: How and why the American security strategy toward terrorism evolved in the aftermath of the September 11 attacks in 2001? Based on the neorealist approach in international relations, this paper attempted to answer that question: first, through defining the concept of terrorism and how the Americans perceive it; second, via pinpointing the characteristic of the American counter-terrorism strategy before September 11 attacks; and third, through examining the effects of those terrorist attacks on that strategy.

The nature of the subject of this study calls for reliance on the analytical descriptive approach to highlight the role and strategy of the USA in the fight against terrorism following the events of September 11, in addition to the use of the system analysis methodology, which can identify the inputs and outputs of the system that had an impact in formulating the US counter-terrorism strategy.

This study has come up with seven findings. The first finding was that the 9/11 attacks served as a turning point of the US counter-terrorism strategy and restructured its agenda. Confronting the communist threat had been its primary objective, until terrorism came to the fore and became its first and foremost priority. The USA vowed that terrorism is its enemy and waged the war on terror to thwart its risk as a global threat. The second finding revolves around the idea of double standards in the American foreign policy. True to its long-standing tradition of favoring its own interests, in complete disregard of the interests of any other party, the USA continued to uphold the double-standards policy.

This study adds a new study to the Arab Library in the field of counter-terrorism studies, national security strategies and American foreign policy. In addition, the researcher seeks to complete the scientific effort to study the US strategy against terrorism, with a clear impact on the development of the situation in the region. This study contributes to the study of how one of the great powers in the international system, the USA, deals with the terrorist organizations that have become widespread in the Arab region.

The coronavirus disease 2019 (COVID-19) pandemic has become a global humanitarian challenge. This scourge has impacted people from all walks of life as well as every economic sector and activity, from travel to automotives, hotels to banking, and supply chain to retail. The pandemic has affected not only physical and mental health but also financial health. Studies have examined the pandemic's economic impact, but very few have examined its impact on personal finances. Efforts to contain the pandemic's spread, such as lockdowns, have resulted in suspended business operations throughout the world that have intensified joblessness. To prepare and protect people from such unforeseen situations, financial education and planning are necessary. We attempt to expand the evidence on this issue by applying a structural equation modelling approach to identify the mediating role of financial literacy programs in preparing and protecting household wealth against sudden worldwide setbacks. The research design is descriptive and exploratory using snowball sampling technique. The data was collected through an internet survey. In total, 400 survey responses were obtained. After testing the measurement model for key validity dimensions, the hypothesised causal relationships are examined in several path models. The results indicated that coronavirus awareness exerts a direct or indirect influence on the financial health of individuals through financial literacy. We conclude that financial literacy has a full mediating effect on the personal finance of individuals during the COVID-19 pandemic. The findings not only contributed to the need and understanding of financial literacy but also have managerial implications. Financial literacy programs provide investment advice and suggestions which are actionable and also work to help individuals to come out stronger in terms of knowledge and skill set when the COVID-19 crisis passes.

The coronavirus disease (COVID-19) pandemic has emerged as an unprecedented health crisis worldwide and heavily disrupted the healthcare supply chain. This study focuses on analysing the different types of disruptions occurring in personal protective equipment (PPE) supply chains during the COVID-19 pandemic and on proposing mitigation strategies that are fit to the global scale and many interdependencies that are characteristic for this pandemic. The authors construct a conceptual system dynamics model (SD) based on the literature and adjusted with the use of empirical data (interviews) to capture the complexity of a global supply chain and identify leverage points (mitigation strategies).

This research follows a mix-methods approach. First, the authors developed a conceptual framework based on four types of disruptions that usually occur during health emergencies (direct effect, policy, supply chain strategy, and behaviourally induced disruptions). Second, the authors collected and analysed data from interviews with experts in the PPE supply chain. Based on the interviews data, the authors developed a conceptual system dynamics (SD) model that allows to capture the complex and dynamic interplay between the elements of the global supply chain system, by highlighting key feedback loops, delays, and the way the mitigation strategies can impact on them. From this analysis, the authors developed four propositions for supply chain risk management (SCRM) in global health emergencies and four recommendations for the policy and decision makers.

The SD model highlights that without a combination of mitigation measures, it is impossible to overcome all disruptions. As such, a co-ordinated effort across the different countries and sectors that experience the disruptions is needed. The SD model also shows that there are important feedback loops, by which initial disruptions create delays and shortages that propagate through the supply chain network. If the co-ordinated mitigation measures are not implemented early at the onset of the pandemic, these disruptions will be persistent, creating potential shortages of PPE and other critical equipment at the onset of a pandemic – when they are most urgently needed.

This research enriches the understanding of the disruptions of PPE supply chains on the systems level and proposes mitigation strategies based on empirical data and the existing literature.