40 research outputs found

    Robust estimation of bacterial cell count from optical density

    Get PDF
    Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

    Contested tourists' border-crossing experiences

    Get PDF
    Airports as borders signify critical thresholds of tourism experiences – arrival and departure. They are also highly contested spaces that produce vastly different and controversial encounters. Tourists legally entering destination airports have expectations of being treated equally until the first segregating lines for home and foreign passports. Here, various levels of mobility rights are bestowed on different passport holders, which requires intersectional scrutiny (Adey, 2017). The inequality in mobility rights derives from an intersection of factors, including identities, social contexts, and power relations (Mooney, 2018). The hierarchy of passports intersects with appearance, gender, religion, disability/ability, and class, producing unequal treatment at borders (Torabian & Mair, 2022). When entering the West, non-Western tourists become the target of additional questioning, checks, and micro-aggressions despite carrying correct travel documents. These tourists endure stress, overt or covert biases, and a myriad of negative emotions, such as humiliation and intimidation (Villegas, 2015). The current research note presents a conceptual discussion concerning tourists' experiences at airport borders. This is an issue largely under-examined in tourism studies, both conceptually and empirically, due to the following reasons. First, tourism research has long been dominated by Eurocentric ideologies and institutions (Ateljevic, Morgan, & Pritchard, 2007). Theories have predominantly been produced and reinforced by scholars from the West (Wijesinghe, Mura & Culala, 2019), who benefit from greater global mobility by being on the higher end of the hierarchy of passports. Such positionality renders border hostility and inequality of mobility rights invisible to them (Ateljević, 2014; Wijesinghe et al., 2019). Second, the airport border is an assemblage of national security, technological surveillance, and economic interests from both public and private sectors (Mohl, 2019). The interplay of "contradictory flows and desires" (Mohl, 2019, p3) leads to stress and tension. Thus, conducting research at airports presents methodological challenges, such as limited access due to security, compromised data quality from fatigued travellers, and disruption to movements. Third, since the media often over-glamorizes tourism experiences (Bandyopadhyay, 2011), travellers often neglect the discriminative encounters and comply with extensive questioning to gain quick entry, as negativity contradicts the pleasure and fantasies tourism marketing promises. This research attends to the recent call for the decolonization of tourism scholarship, especially the Anglo-Western-centric knowledge, and surfaces the under-represented voices (Yang & Ong, 2020; Chambers & Buzinde, 2015). Neo-colonial domination goes beyond the colonizer's political and economic dominance over colonized (Cywiński, 2015). Tourism still inherits colonial mindsets and practices for the privileged (McCabe & Diekmann, 2015). This study focuses on the unequal mobility rights for tourists from different regions (Torabian & Mair, 2022), a prime yet understudied example of such a colonial mindset
    corecore