Simplified modal analysis of multi-storey RC buildings for application in seismic retrofitting

This paper presents a novel simplified approach for determining the fundamental vibration characteristics of reinforced concrete (RC) buildings for application in the seismic retrofitting of substandard multi-storey RC building structures. Even when retrofitted, such structures would likely respond inelastically under a major earthquake, where the seismic response is most realistically represented by computationally expensive nonlinear dynamic analysis. Towards reducing such computational demands, the capacity spectrum method (CSM) offers a practical design and assessment approach which utilises nonlinear static pushover analysis in conjunction with the dynamic characteristics of a structure to establish whether the seismic capacity of the structure meets the demands of seismic ground motion. In this respect, the dynamic characteristics of a structure can be ordinarily obtained by performing conventional direct modal analysis which requires the assembly of mass and stiffness matrices to solve the eigenvalue problem. This paper presents the development of a simplified numerical approach that determines the translational modes of vibration and the associated periods for a retrofitted building structure in both horizontal directions in a simplistic manner without assembling the mass and stiffness matrices. The accuracy of the proposed simplified approach is verified for realistic structures via comparisons against direct eigenvalue analysis. This, along with planned research on simplified pushover analysis, paves the way for the practical seismic retrofitting of substandard reinforced concrete buildings within the CSM framework

Mechanical Ventilation. Total Eclipse of the Heart (Editorial)

Results from recent large randomized trials investigating the use of high PEEP in patients without ARDS all suggest that high levels may increase mortality due to hypotension and bradycardia. A careful assessment of cardiac function — with particular focus on the right ventricle — should be performed before planning our ventilation strategy in any setting, including COVID-19 and ARDS in general. Mechanical ventilation should be respectful in regards of heart function, and tolerant with moderate hypoxia and hypercapnia, noninvasive (whenever possible) and synchronized

Role of antiseptics in the prevention and treatment of infections in nursing homes

Inadequate infection control, wound care, and oral hygiene protocols in nursing homes provide challenges to residents’ quality of life. Based on the outcomes from a focus group meeting and a literature search, this narrative review evaluates the current and potential roles of antiseptics within nursing home infection management procedures. We examine contemporary strategies and concerns within the management of meticillin-resistant Staphylococcus aureus (MRSA; including decolonization regimes), chronic wound care, and oral hygiene, and review the available data for the use of antiseptics, with a focus on povidone-iodine. Compared with chlorhexidine, polyhexanide, and silver, povidone-iodine has a broader spectrum of antimicrobial activity, with rapid and potent activity against MRSA and other microbes found in chronic wounds, including biofilms. As no reports of bacterial resistance or cross-resistance following exposure to povidone-iodine exist, it may be preferable for MRSA decolonization compared with mupirocin and chlorhexidine, which can cause resistant MRSA strains. Povidone-iodine oral products have greater efficacy against oral pathogens compared with other antiseptics such as chlorhexidine mouthwash, highlighting the clinical benefit of povidone-iodine in oral care. Additionally, povidone-iodine-based products, including mouthwash, have demonstrated rapid in vitro virucidal activity against SARS-CoV-2 and may help reduce its transmission if incorporated into nursing home coronavirus 2019 control protocols. Importantly, povidone-iodine activity is not adversely affected by organic material, such as that found in chronic wounds and the oral cavity. Povidone-iodine is a promising antiseptic agent for the management of infections in the nursing home setting, including MRSA decolonization procedures, chronic wound management, and oral care.N/

Scaling up sustainability in commodity agriculture: Transferability of governance mechanisms across the coffee and cattle sectors in Brazil

A number of governance mechanisms address socio-environmental challenges associated with commodity agriculture in tropical forested countries. Governance mechanisms that prove effective in one agricultural sector are often applied to other sectors as well. For example, voluntary certification programs have been adopted by producers of commodities as diverse as beef, coffee, palm oil, and soy. However, there are substantial differences in the extent to which governance mechanisms scale up and achieve impact in different sectors. This paper analyzes how the potential for scaling up a particular governance mechanism is influenced by environmental, market, and social geographies that differ between sectors. Through stakeholder interviews, farm-level surveys, and a literature review, we examine two types of voluntary governance mechanisms (third-party certification, and sustainable intensification programs) in the coffee and cattle sectors in Brazil, to understand why the two governance mechanisms have scaled differently between these two sectors. We find that third-party certification programs have scaled up relatively well in Brazil\u27s coffee sector, more so than its cattle sector, in part owing to differences in sustainability priorities, market orientations, supply chain traceability, and social networks between the two sectors. We also find that pilot sustainable intensification programs in the cattle sector have had more success than certification in engaging farmers, in part because they involve less investment from participating farmers. We conclude that the distribution and quality of environmental resources, markets, knowledge, actors, and networks can play an important role in the ability of a governance mechanism to effectively take root