Fluid mixing by curved trajectories of microswimmers

We consider the tracer diffusion $D_{rr}$ that arises from the run-and-tumble motion of low Reynolds number swimmers, such as bacteria. Assuming a dilute suspension, where the bacteria move in uncorrelated runs of length $\lambda$, we obtain an exact expression for $D_{rr}$ for dipolar swimmers in three dimensions, hence explaining the surprising result that this is independent of $\lambda$. We compare $D_{rr}$ to the contribution to tracer diffusion from entrainment.Comment: 5 pages, 2 figure

Stirring by swimmers in confined microenvironments

We consider the tracer diffusion $D_{rr}$ that arises from the run-and-tumble motion of low Reynolds number swimmers, such as bacteria. In unbounded dilute suspensions, where the dipole swimmers move in uncorrelated runs of length $\lambda$, an exact solution showed that $D_{rr}$ is independent of $\lambda$. Here we verify this result in numerical simulations for a particular model swimmer, the spherical squirmer. We also note that in confined microenvironments, such as microscopic droplets, microfluidic devices and bacterial microzones in marine ecosystems, the size of the system can be comparable to $\lambda$. We show that this effect alone reduces the value of $D_{rr}$ in comparison to its bulk value, and predict a scaling form for its relative decrease.Comment: submitted to JSTA

The Use of Mother Tongue in General English Program for Teenagers in the Second and Fourth Levels

This study reports the teacher's use of mother tongue (Bahasa Indonesia) in English as Foreign Language (EFL) classroom in Indonesia. The study was conducted in an English language course for teenagers, and focused more in the second and fourth level. It was revealed that beside English language, Bahasa Indonesia was used by the teachers as the medium of instruction for some functions: conveying and checking the meaning of words/sentences, explaining grammar, organizing tasks, maintaining discipline, and gaining contact with individual student; and the teachers' reason in using Bahasa Indonesia was to make sure that the students understand about what they delivered. In addition, some similarities and differences were found in the comparison of the second and fourth levels

MARKET SHARE, CAPACITY UTILIZATION, RESOURCE CONSERVATION, AND TRADABLE QUOTAS

This paper examines the impact of the introduction of Individual Transferable Quotas (ITQs) on catch, market share, and capacity utilization of firms in the Mid Atlantic Surf Clam and Ocean Quahog (SCOQ) Fishery. Via the production function framework, catch and market share regression models are utilized in examining the effects of operator size, vessel age, and alternative product catch variables on industrial structure and how such effects changed after ITQs were introduced. Results indicate that in both fisheries, the ITQ system enhanced the value of each vessel by allowing vessel owners to apply greater effort to fewer boats, thus reducing excess capacity in the fishery. Results also indicate an overall resource conservation effect of ITQ introduction in the surf clam fishery. These results suggest that in the presence of ITQs, overall efficiency was enhanced in the SCOQ fishery.Resource /Energy Economics and Policy,

Wrangling environmental exposure data: guidance for getting the best information from your laboratory measurements.

BACKGROUND:Environmental health and exposure researchers can improve the quality and interpretation of their chemical measurement data, avoid spurious results, and improve analytical protocols for new chemicals by closely examining lab and field quality control (QC) data. Reporting QC data along with chemical measurements in biological and environmental samples allows readers to evaluate data quality and appropriate uses of the data (e.g., for comparison to other exposure studies, association with health outcomes, use in regulatory decision-making). However many studies do not adequately describe or interpret QC assessments in publications, leaving readers uncertain about the level of confidence in the reported data. One potential barrier to both QC implementation and reporting is that guidance on how to integrate and interpret QC assessments is often fragmented and difficult to find, with no centralized repository or summary. In addition, existing documents are typically written for regulatory scientists rather than environmental health researchers, who may have little or no experience in analytical chemistry. OBJECTIVES:We discuss approaches for implementing quality assurance/quality control (QA/QC) in environmental exposure measurement projects and describe our process for interpreting QC results and drawing conclusions about data validity. DISCUSSION:Our methods build upon existing guidance and years of practical experience collecting exposure data and analyzing it in collaboration with contract and university laboratories, as well as the Centers for Disease Control and Prevention. With real examples from our data, we demonstrate problems that would not have come to light had we not engaged with our QC data and incorporated field QC samples in our study design. Our approach focuses on descriptive analyses and data visualizations that have been compatible with diverse exposure studies with sample sizes ranging from tens to hundreds of samples. Future work could incorporate additional statistically grounded methods for larger datasets with more QC samples. CONCLUSIONS:This guidance, along with example table shells, graphics, and some sample R code, provides a useful set of tools for getting the best information from valuable environmental exposure datasets and enabling valid comparison and synthesis of exposure data across studies

Spiritual Care Competency of Critical Care Nurses: A Literature Review

While caring for their patients, nurses often encounter spiritual needs. In a study with 241 hospice, palliative care, and holistic nurses, “all respondents (100%) indicated they had encountered a patient with spiritual needs throughout their nursing clinical practice” (Lukovsky et al., 2021, p. 32). Despite the prevalence of spiritual needs, many nurses feel unable to confront spiritual issues among their patients. According to a survey conducted among 4054 nurses from the UK, “almost 93% of the nurses surveyed believed spiritual care should be addressed, yet only 5.3% felt always able to meet the spiritual need of patients on a regular basis” (Lukovsky et al., 2021, p. 35). Spiritual care, as discussed in this literature review, “is the recognition and support of the religion and/or spirituality dimensions of illness” (Lukovsky et al., 2021, p. 28). While it is important for all nurses to be competent in holistic care, it is especially vital for critical care nurses. Research shows “that patients in critical-care units indicate spiritual needs more frequently than do patients in other hospital units” (Ruth-Sahd et al., 2018, p. 18). According to the American Association of Critical Care Nurses, meeting patients’ spiritual needs is an essential part in promoting healing (Ruth-Sahd et al., 2018). Consequently, it is paramount that critical care nurses are equipped with the proper resources to address these concerns