Search Results (55)

In this paper, we present a fast and accurate numerical approach applied to specific American-style derivatives, namely American power call and put options, whose main feature is that the underlying asset is raised to a power. The study is set in the Black–Scholes framework, and we consider continuously paying dividends assets and arbitrary positive values for the power. It is important to note that although a log-normal process raised to a power is again log-normal, the resulting change in variables may lead to a negative dividend rate, and this case remains largely understudied in the literature. We derive closed-form formulas for the perpetual options’ optimal boundaries and for the fair prices. For finite maturities, we approximate the optimal boundary using some first-hitting properties of the Brownian motion. As a consequence, we obtain the option price quickly and with relatively high accuracy—the error is at the third decimal position. We further provide a comprehensive analysis of the impact of the parameters on the options’ value, and discuss ordinary European and American capped options. Various numerical examples are provided. Full article

In this paper, we study perpetual American put options with a generalized standard put payoff and establish sufficient conditions for the existence and uniqueness of the solution to the associated pricing problem. As a key tool, we express the Black–Scholes operator in terms of elasticity. This formulation enables us to demonstrate that the considered pricing problem admits a unique solution when the payoff function exhibits strictly decreasing elasticity with respect to the underlying asset. Furthermore, this approach allows us to derive closed-form solutions for option pricing. Full article

With the morbidity of cancer currently on a perpetual rise, there is a critical need for new treatment options. Current therapeutic options, such as chemotherapy and radiotherapy, are frequently employed; however, the high rate of recurrence underscores the incomplete understanding of tumour growth, progression, and the intricacies of their microenvironments. In this study, we review the roles that galectin-1 (Gal1) plays in suppressing immune surveillance in the tumour microenvironment. Studies have shown that Gal1 changes the immune system parameters: suppressing T cell function, sensitising resting T lymphocytes to Fas/FasL, decreasing cell proliferation, reducing adhesion to extracellular matrix, inhibiting Th1 cytokines, increasing M2 phenotype macrophages, and promoting angiogenesis. Gal1 has garnered increasing attention as a potential therapeutic target due to its involvement in tumour progression and immune evasion. Given the limitations and toxic side effects associated with current treatment options, alternative strategies targeting Gal1 have been explored for their therapeutic potential. Approaches such as OTX008, anti-Gal1 monoclonal antibodies, and Gal1-targeted vaccines have demonstrated the ability to downregulate tumour progression by inhibiting Gal1 activity. These findings highlight the therapeutic promise of Gal1 not only as a novel target for cancer therapy but also as a potential prognostic biomarker, offering opportunities for the development of more effective and less toxic treatment strategies. Full article

We introduce a fairly general, recombining trinomial tree model in the natural world. Market completeness is ensured by considering a market consisting of two risky assets, a riskless asset and a European option. The two risky assets consist of a stock and a perpetual derivative of that stock. The option has the stock and its derivative as its underlying. Using a replicating portfolio, we develop prices for European options and generate the unique relationships between the risk-neutral and real-world parameters of the model. We discuss calibration of the model to empirical data in the cases in which the risky asset returns are treated as either arithmetic or logarithmic. From historical price and call option data for select large cap stocks, we develop implied parameter surfaces for the real-world parameters in the model. Full article

Virtual reality (VR) demonstrates significant potential to improve rehabilitation outcomes for musculoskeletal conditions and associated chronic pain. However, the field faces notable challenges, including inconsistent terminology, a lack of specialized/comprehensive software solutions, and an overwhelming variety of hardware options, which can make it difficult for healthcare professionals without technical expertise to identify the most suitable tools for clinical use. This article explores the current state of VR in the rehabilitation of musculoskeletal conditions and chronic pain, focusing on terminology discrepancies, available hardware and software solutions, and key professional associations shaping the field. A review of the current state of terminology is essential to address inconsistencies that risk perpetuating misuse and to facilitate clearer communication. Building on this review, we propose a conceptual framework for understanding VR that aligns more closely with the capabilities of current VR technology. A comprehensive overview of VR hardware and software can assist healthcare professionals in selecting appropriate technologies for clinical practice, guide researchers in designing interventions, and inform developers on unmet needs in the field. Furthermore, understanding key professional associations provides valuable direction for those engaged in virtual rehabilitation, enabling them to access resources, foster collaboration, and stay informed about the latest advancements in the domain. This review addresses the significant confusion regarding the understanding of VR, particularly in relation to its classification based on levels of immersion. Accordingly, it proposes a framework that contributes to a standardized approach to understanding VR. Additionally, it highlights the lack of VR solutions tailored to the needs of patients with musculoskeletal conditions and associated chronic pain, emphasizing the necessity for further development in this area. Full article

The degradation of elastic fibers is a fundamental characteristic of pulmonary emphysema, resulting in the release of proinflammatory elastin peptides. The findings discussed in this paper support the hypothesis that these peptides act as carriers of disease, interacting with elastin receptor complexes that promote inflammation, elastic fiber damage, and airspace enlargement. Studies from our laboratory show that the breakdown of these fibers is significantly enhanced by intratracheal instillation of elastin peptides in a lipopolysaccharide-induced model of acute lung injury. This result is consistent with a mechanism of elastic fiber injury in which an expanding pool of elastin peptides generates further elastolysis. The accelerating release of the peptides results in a self-perpetuating disease process with the features of an epidemic, where self-replicating agents spread disease. As in the case of an epidemic, elastin peptides resemble disease vectors that transmit alveolar wall injury throughout the lung. This concept may provide a framework for developing novel therapeutic approaches specifically designed to protect elastic fibers from various enzymatic and oxidative insults, thereby slowing the progression of a disease with no robust treatment options. Full article

Risk is often the most concerning factor in financial transactions. Option Greeks provide valuable insights into the risks inherent in option trading and serve as tools for risk mitigation. Traditionally, scholars compute option Greeks through extensive calculations. This article introduces an alternative method that bypasses conventional derivative computation using the Mellin transform and its properties. Specifically, we derive Greeks for perpetual American options with general payoffs, represented as piecewise linear functions, and examine higher-order risk metrics for practical implications. Examples are provided to illustrate the effectiveness of our approach, offering a novel perspective on calculating and interpreting option Greeks. Full article

Eating behavior encompasses the psychological, physiological, and environmental factors influencing food intake. Dysregulation in eating behavior, such as emotional eating, binge eating, or loss of satiety signals, contributes to excessive caloric intake and weight gain. These behaviors are often linked to hormonal imbalances, stress, or genetic predisposition. Obesity is a chronic, multifactorial disease characterized by excessive body fat accumulation, with a body mass index (BMI) ≥ 30 kg/m² often used for diagnosis. It is associated with significant morbidity, including type 2 diabetes, cardiovascular disease, and obstructive sleep apnea. Pathophysiological mechanisms underlying obesity include insulin resistance, leptin dysregulation, and altered gut microbiota, which perpetuate metabolic derangements. Lifestyle interventions remain first-line treatment, but sustained weight loss is challenging for many patients. Bariatric surgery is a therapeutic option for individuals with severe obesity (BMI ≥ 40 kg/m² or ≥35 kg/m² with comorbidities) who have failed conservative management. Procedures such as Roux-en-Y gastric bypass and sleeve gastrectomy alter gastrointestinal anatomy, promoting weight loss through restriction, malabsorption, and hormonal modulation (e.g., increased GLP-1 secretion). Bariatric surgery improves obesity-related comorbidities and enhances quality of life. However, it requires lifelong medical follow-up to address potential nutritional deficiencies and ensure sustainable outcomes. Full article

Chronic obstructive pulmonary disease (COPD) is a prevalent chronic condition associated with substantial global morbidity and mortality. Primarily caused by prolonged exposure to harmful agents such as dust and gases, COPD is characterized by persistent airflow limitation, clinically manifesting as chronic cough, sputum production, and dyspnea. The disease course alternates between stable phases and exacerbations, with the latter often associated with pathogenic colonization of the respiratory tract. This review examines the immunological underpinnings of COPD, emphasizing the interplay between innate and adaptive immunity in disease pathogenesis. Dysregulated immune responses to environmental factors perpetuate chronic inflammation, resulting in progressive pulmonary epithelial damage and connective tissue hyperplasia, which compromise gas exchange. Exacerbations further exacerbate respiratory failure, aggravating patient symptoms and accelerating disease progression. Despite advances in COPD management, effective therapeutic options remain limited. Current treatments primarily aim to alleviate symptoms, reduce immune activation, and manage infections, yet many patients experience suboptimal outcomes. This review highlights the potential of novel therapeutic approaches targeting immune system cells and pathways. In particular, it explores the promise of oral bacterial vaccines as immunomodulatory agents to enhance immune responses and improve clinical outcomes in COPD, addressing critical gaps in current treatment paradigms. Full article

In this article, I argue that Eurafricans’ invisibility in Zambia’s national census, history, and social framework is an echo of colonial whiteness stemming from the destructive legacy of illegitimacy perpetuated by British officials in Northern Rhodesia (present-day Zambia) during the colonial era (1924–64), which continues to the present day. This is evidenced by the absence of Eurafricans in the Zambia national censuses. This contribution calls for the British government to apologise to the Eurafrican community for the legacy of illegitimacy and intergenerational racial trauma it bestowed on the community. Zambia’s tribal ‘ethnic’ and ‘linguistics’ census classification options prevent a comprehensive understanding of Zambia’s multi-racial history and the development of a hybrid space that embraces a ‘mixed-race’ Eurafrican (of European and African heritage) Zambian identity. Through an autoethnographic account of my Eurafrican uncle Aaron Milner, I reflect on Zambian Eurafricans’ historical racial positioning as ‘inferior interlopers’, which has contributed to their obscurity in Zambia’s national history and census. However, my reflection goes beyond Milner’s story in Zambia. It is my entryway to highlight how race and colonial whiteness interconnected and underpinned racial ideology in the wider British Empire, and to draw attention to its echoes in various contemporary sociopolitical contexts, including census terminology in Australia and Zambia and Western nations’ anti-Black immigration policies. Full article

The “One Health approach” has evidenced the significant impact of xenobiotic exposure to health, and humans are a relevant target for their toxic effects. Bisphenol A (BPA) exerts a ubiquitous exposure source in all ecosystems. Given its endocrine-disrupting and harmful consequences on health, several countries have enforced new regulations to reduce exposure to BPA. Cardiovascular diseases (CVDs) are complex conditions that lead to higher mortality worldwide, where family history, lifestyle, and environmental factors, like BPA exposure, have a remarkable contribution. This chemical compound is the most widely used in plastic and epoxy resin manufacturing and has been associated with effects on human health. Therefore, new-generation bisphenols (NGBs) are replacing BPA use, arguing that they do not harm health. Nonetheless, the knowledge about whether NGBs are secure options is scanty. Although BPA’s effects on several organs and systems have been documented, the role of BPA and NGBs in CVDs has yet to be explored. This review’s goals are focused on the processes of endothelial activation (EA)–endothelial dysfunction (ED), a cornerstone of CVDs development, bisphenols’ (BPs) effects on these processes through oxidant and antioxidant system alteration. Despite the scarce evidence on pro-oxidant effects associated with NGBs, our review demonstrated a comparable harmful effect on BPA. The results from the present review suggest that the biological mechanisms to explain BPs cardiotoxic effects are the oxidant stress ↔ inflammatory response ↔ EA ↔ ED → atherosclerotic plate → coagulation promotion. Other effects contributing to CVD development include altered lipid metabolism, ionic channels, and the activation of different intracellular pathways, which contribute to ED perpetuation in a concerted manner. Full article

We engage the decolonial option from Abya Yala, el Caribe, and Eastern Europe with an interest in suicide from our struggles as racialized people and our dehumanization, whereby, for many of us, suicide is not an act of autonomy or resistance but the reaffirmation of death as an ongoing state of living. This is the permanent reality of existence concocted by coloniality and its constitutive effect on lived experience. We depart from the assumption that suicide materializes according to someone’s thinking about the world and of a particular philosophy. Thus, predominantly, suicide is the universal name someone’s knowledge has given to an experience; and whose experience is named as such is consequently universally configured as a suicidal being. Here, we discuss suicide from understandings that come from non-discursive domains, and from a different genealogy than western Europe’s; the coloniality of the senses, time and being. We attempt to story what violence does in relation to an already violent circumstance, suicide, therapists and hotline workers, and undocumented lives in the U.S., when singularly imposing one way of the world. We are interested in adding visibility to the legacy of erasure and violence that the epistemologies and ontologies of suicide, suicide assessments, and therapists’ clinical judgements perpetuate; further sustaining dehumanization and the imposition of death as a constant in life. We discuss a crisis suicide call as the lay of the land of modernity’s suicide assessments, constructed as an assemblage from our shared memories on many stories we have heard in our work. We annotate it as it unfolds, reflecting upon our expected practices in institutionalized settings, under the control of modernity/coloniality that discriminates against pluriversal temporalities, sensings, and relationalities. Full article

The impact of racial healthcare disparities has been well documented. Adverse social determinants of health, such as poverty, inadequate housing, and limited access to healthcare, are intricately linked to these disparities and negative health outcomes, highlighting the profound impact that social and economic factors have on individuals’ overall well-being. Recent evidence underscores the role of residential location on individual health outcomes. Despite the importance of a healthy lifestyle, regular physical activity, balanced nutrition, and stress management for favorable health outcomes, individuals living in socioeconomically disadvantaged areas may face obstacles in achieving these practices. Adverse living conditions, environmental factors, and systemic biases against Black Americans perpetuate allostatic load. This, compounded by decreased physical activity and limited healthy food options, may contribute to increased oxidative stress and inflammation, fundamental drivers of morbidities such as cardiovascular disease and cancer. Herein, we perform a narrative review of associations between healthcare disparities, chronic stress, allostatic load, inflammation, and cancer in Black Americans, and we discuss potential mechanisms and solutions. Additional research is warranted in the very important area of cancer disparities. Full article

We present a unified, market-complete model that integrates both Bachelier and Black–Scholes–Merton frameworks for asset pricing. The model allows for the study, within a unified framework, of asset pricing in a natural world that experiences the possibility of negative security prices or riskless rates. Unlike the classical Black–Scholes–Merton, we show that option pricing in the unified model differs depending on whether the replicating, self-financing portfolio uses riskless bonds or a single riskless bank account. We derive option price formulas and extend our analysis to the term structure of interest rates by deriving the pricing of zero-coupon bonds, forward contracts, and futures contracts. We identify a necessary condition for the unified model to support a perpetual derivative. Discrete binomial pricing under the unified model is also developed. In every scenario analyzed, we show that the unified model simplifies to the standard Black–Scholes–Merton pricing under specific limits and provides pricing in the Bachelier model limit. We note that the Bachelier limit within the unified model allows for positive riskless rates. The unified model prompts us to speculate on the possibility of a mixed multiplicative and additive deflator model for risk-neutral option pricing. Full article

The perpetually fluctuating economic and environmental climate significantly increases the demand for alternative fuel sources. The utilization of hydrogen gas is a viable option for such a fuel source. Hydrogen is one of the most energy-dense known substances; however, it is unfortunately also highly volatile, especially in the diatomic gaseous state most commonly used to store it. The utilization of a hydrogen feedstock material such as sodium borohydride (NaBH₄) may prove to mitigate this danger. When NaBH₄ reacts with water, hydrogen stored within its chemical structure is released. However, the rate of hydrogen release is slow and thus necessitates a catalyst. Platinum nanoparticles were chosen to act as a catalyst for the reaction, and to prevent them from conglomerating, they were embedded in a backbone of mesoporous carbon material (MCM) derived from a sustainable corn starch source. The nanocomposite (Pt-MCM) was characterized via transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). Pt-MCM underwent catalytic testing, revealing that the catalytic activity of the Pt-MCM composite catalysts increased with increasing quantities of sodium borohydride, lower pH levels, and higher temperatures. The activation energy of the catalyzed reaction was found to be 37.7 kJ mol⁻¹. Reusability experiments showed an initial drop off in hydrogen production after the first trial but subsequent stability. This Pt-MCM catalyst’s competitive activation energy and sustainable MCM backbone derived from readily available corn starch make it a promising option for optimizing the hydrogen generation reaction of NaBH₄. Full article