Continuous-flow IRMS technique for determining the 17O excess of CO2 using complete oxygen isotope exchange with cerium oxide

This paper presents an analytical system for analysis of all single substituted isotopologues (¹²C¹⁶O¹⁷O, ¹²C¹⁶O¹⁸O, ¹³C¹⁶O¹⁶O) in nanomolar quantities of CO₂ extracted from stratospheric air samples. CO₂ is separated from bulk air by gas chromatography and CO₂ isotope ratio measurements (ion masses 45 / 44 and 46 / 44) are performed using isotope ratio mass spectrometry (IRMS). The ¹⁷O excess (Δ¹⁷O) is derived from isotope measurements on two different CO₂ aliquots: unmodified CO₂ and CO₂ after complete oxygen isotope exchange with cerium oxide (CeO₂) at 700 °C. Thus, a single measurement of Δ¹⁷O requires two injections of 1 mL of air with a CO₂ mole fraction of 390 μmol mol⁻¹ at 293 K and 1 bar pressure (corresponding to 16 nmol CO₂ each). The required sample size (including flushing) is 2.7 mL of air. A single analysis (one pair of injections) takes 15 minutes. The analytical system is fully automated for unattended measurements over several days. The standard deviation of the ¹⁷O excess analysis is 1.7‰. Multiple measurements on an air sample reduce the measurement uncertainty, as expected for the statistical standard error. Thus, the uncertainty for a group of 10 measurements is 0.58‰ for Δ ¹⁷O in 2.5 h of analysis. 100 repeat analyses of one air sample decrease the standard error to 0.20‰. The instrument performance was demonstrated by measuring CO₂ on stratospheric air samples obtained during the EU project RECONCILE with the high-altitude aircraft Geophysica. The precision for RECONCILE data is 0.03‰ (1σ) for δ¹³C, 0.07‰ (1σ) for δ¹⁸O and 0.55‰ (1σ) for δ¹⁷O for a sample of 10 measurements. This is sufficient to examine stratospheric enrichments, which at altitude 33 km go up to 12‰ for δ¹⁷O and up to 8‰ for δ¹⁸O with respect to tropospheric CO₂ : δ¹⁷O ~ 21‰ Vienna Standard Mean Ocean Water (VSMOW), δ¹⁸O ~ 41‰ VSMOW (Lämmerzahl et al., 2002). The samples measured with our analytical technique agree with available data for stratospheric CO₂

Evaluating the Application of Program Outcomes to Study Abroad Experiences

Study abroad is a critical component of a comprehensive higher education experience in today’s global society. The Institute of International Education (IIE) reported that, in 2013–2014, 304,467 U.S. students participated in study abroad. This number has more than tripled over the last two decades, and while short-term study abroad is still the most popular, the number of American students spending a semester or a year abroad is also increasing (IIE). According to Kuh, O’Donnell, and Reed, study abroad has been deemed a high-impact practice, and, as an experiential approach to global learning, study abroad has the power to transform the lives of college students who are given the opportunity to participate and broaden their education. A search through the 2015 annual conference program of the National Collegiate Honors Council (NCHC) turned up a dozen sessions focusing on the topic of study abroad, demonstrating that a growing number of honors programs and colleges are encouraging or requiring study abroad. Many programs now offer and support honors semesters abroad or organized, faculty- led summer trips. According to Scott, 66% of honors colleges and 44% of honors programs at four-year institutions support study abroad that includes academic coursework, and many provide financial support to students studying abroad. Given this high level of support, in conjunction with an era of fiscal exigency, examination of the impact and benefits of study abroad is especially important. Although program outcomes vary, diversity, intercultural competence, and global citizenship are goals shared in some form by many honors programs and colleges. Study abroad is often the most direct way to foster these outcomes because it gives students opportunities to experience unfamiliar settings that promote inclusivity and reduce ethnocentrism, yet global citizenship is not the only area in which a student might experience growth through this type of experience. The purpose of our study is to examine the perceived and documented enrichments to the academic experiences of study abroad students in the Schedler Honors College Travel Abroad Grant (TAG) program. In the article “Building an Honors Education for the Twenty-First Century: Making Connections In and Outside the Classroom,” Alger points out that “at a time when many people have called for greater accountability in higher education, we must be prepared to articulate and assess student learning outcomes much more clearly than we have in the past” (63). Heeding this assertion, honors administrators must be prepared to defend their support of study abroad if they are going to be able to fund these types of experiences in the future

Evaluating the Application of Program Outcomes to Study Abroad Experiences

Study abroad is a critical component of a comprehensive higher education experience in today’s global society. The Institute of International Education (IIE) reported that, in 2013–2014, 304,467 U.S. students participated in study abroad. This number has more than tripled over the last two decades, and while short-term study abroad is still the most popular, the number of American students spending a semester or a year abroad is also increasing (IIE). According to Kuh, O’Donnell, and Reed, study abroad has been deemed a high-impact practice, and, as an experiential approach to global learning, study abroad has the power to transform the lives of college students who are given the opportunity to participate and broaden their education. A search through the 2015 annual conference program of the National Collegiate Honors Council (NCHC) turned up a dozen sessions focusing on the topic of study abroad, demonstrating that a growing number of honors programs and colleges are encouraging or requiring study abroad. Many programs now offer and support honors semesters abroad or organized, faculty- led summer trips. According to Scott, 66% of honors colleges and 44% of honors programs at four-year institutions support study abroad that includes academic coursework, and many provide financial support to students studying abroad. Given this high level of support, in conjunction with an era of fiscal exigency, examination of the impact and benefits of study abroad is especially important. Although program outcomes vary, diversity, intercultural competence, and global citizenship are goals shared in some form by many honors programs and colleges. Study abroad is often the most direct way to foster these outcomes because it gives students opportunities to experience unfamiliar settings that promote inclusivity and reduce ethnocentrism, yet global citizenship is not the only area in which a student might experience growth through this type of experience. The purpose of our study is to examine the perceived and documented enrichments to the academic experiences of study abroad students in the Schedler Honors College Travel Abroad Grant (TAG) program. In the article “Building an Honors Education for the Twenty-First Century: Making Connections In and Outside the Classroom,” Alger points out that “at a time when many people have called for greater accountability in higher education, we must be prepared to articulate and assess student learning outcomes much more clearly than we have in the past” (63). Heeding this assertion, honors administrators must be prepared to defend their support of study abroad if they are going to be able to fund these types of experiences in the future

Coherent population oscillations with nitrogen-vacancy color centers in diamond

We present results of our research on two-field (two-frequency) microwave spectroscopy in nitrogen-vacancy (NV-) color centers in a diamond. Both fields are tuned to transitions between the spin sublevels of the NV- ensemble in the 3A2 ground state (one field has a fixed frequency while the second one is scanned). Particular attention is focused on the case where two microwaves fields drive the same transition between two NV- ground state sublevels (ms=0 -> ms=+1). In this case, the observed spectra exhibit a complex narrow structure composed of three Lorentzian resonances positioned at the pump-field frequency. The resonance widths and amplitudes depend on the lifetimes of the levels involved in the transition. We attribute the spectra to coherent population oscillations induced by the two nearly degenerate microwave fields, which we have also observed in real time. The observations agree well with a theoretical model and can be useful for investigation of the NV relaxation mechanisms.Comment: 17 page

Structure of the Afferent Terminals in Terminal Ganglion of a Cricket and Persistent Homology

We use topological data analysis to investigate the three dimensional spatial structure of the locus of afferent neuron terminals in crickets Acheta domesticus. Each afferent neuron innervates a filiform hair positioned on a cercus: a protruding appendage at the rear of the animal. The hairs transduce air motion to the neuron signal that is used by a cricket to respond to the environment. We stratify the hairs (and the corresponding afferent terminals) into classes depending on hair length, along with position. Our analysis uncovers significant structure in the relative position of these terminal classes and suggests the functional relevance of this structure. Our method is very robust to the presence of significant experimental and developmental noise. It can be used to analyze a wide range of other point cloud data sets

What is the impact of physical effort on the diagnosis of concussion?

Objective: Sport-related concussion commonly occurs in contact sports such as rugby. To date, diagnosis is based on the realization of clinical tests conducted pitch-side. Yet, the potential effect of prior physical effort on the results of these tests remains poorly understood. The purpose of this study was to determine whether preceding physical effort can influence the outcome of concussion assessments. Design: Prospective observational study. Setting: University Medicine Center Patients: A cohort of 40 subjects (20 rugby players and 20 athletes from a range of sports). Intervention: A concussion assessment was performed immediately following physical activity. Following a period of 6 months and under the same experimental conditions, the same cohort performed the same tests in resting conditions. Main outcome measure: Results of concussion tests. Results: In both cohorts, the comparison for post-exercise and rest assessments demonstrated a most likely moderate-to-very large increase in the number of symptoms, severity of symptoms and BESS score. In the rugby cohort, scores for concentration, delayed memory and SAC, likely-to-most likely decreased following completion of physical activity compared to baseline values. The between-cohort comparison showed a greater impact post-exercise in the rugby players for delayed recall (0.73±0.61, 93/7/1) and SAC score (0.75±0.41, 98/2/0). Conclusion: Physical activity altered the results of concussion diagnostic tests in athletes from a range of sports and notably in rugby players. Therefore, physical efforts prior to the concussion incident should be accounted for during pitch-side assessments and particularly during rugby competition and training

Phylogeny and systematics of the "Pronophila clade," with 2 new genera to resolve the formerly polyphyletic genus Pseudomaniola (Lepidoptera: Nymphalidae: Satyrinae)

Analysis of a target enrichment molecular dataset confirms the monophyly of the Neotropical montane butterfly group known as the Pronophila Westwood clade, 1 of 2 major lineages of the satyrine subtribe Pronophilina. The Pronophila clade comprises 18-20 recognized genera and some 125 species. Within this group, the genus Pseudomaniola Röber appears as paraphyletic, and is split here into 3 genera, Pseudomaniola sensu novum with 6 species, including 4 previously considered as subspecies of P. phaselis (Hewitson), the monobasic Fahraeusia Pyrcz n. gen. for Catargynnis asuba Thieme, n. comb., and Boyeriana Pyrcz, Espeland & Willmott n. gen., with 9 species. The adults of all 3 genera can be recognized by their wing color patterns, but the strongest synapomorphies are found in the genitalia, especially those of the male, supporting the above systematic de cisions. Notable differences are also found in scale organization and morphology. A divergence time analysis suggests that Fahraeusia diverged from Pseudomaniola + Boyeriana in the mid-Miocene, around 12 Mya, and the subsequent separation of the last 2 genera occurred at the start of the Pliocene at around 5 Mya

Genomic insights into the rapid emergence and evolution of MDR in Staphylococcus pseudintermedius.

OBJECTIVES: MDR methicillin-resistant Staphylococcus pseudintermedius (MRSP) strains have emerged rapidly as major canine pathogens and present serious treatment issues and concerns to public health due to their, albeit low, zoonotic potential. A further understanding of the genetics of resistance arising from a broadly susceptible background of S. pseudintermedius is needed. METHODS: We sequenced the genomes of 12 S. pseudintermedius isolates of varied STs and resistance phenotypes. RESULTS: Nine distinct clonal lineages had acquired either staphylococcal cassette chromosome (SCC) mec elements and/or Tn5405-like elements carrying up to five resistance genes [aphA3, sat, aadE, erm(B), dfrG] to generate MRSP, MDR methicillin-susceptible S. pseudintermedius and MDR MRSP populations. The most successful and clinically problematic MDR MRSP clones, ST68 SCCmecV(T) and ST71 SCCmecII-III, have further accumulated mutations in gyrA and grlA conferring resistance to fluoroquinolones. The carriage of additional mobile genetic elements (MGEs) was highly variable, suggesting that horizontal gene transfer is frequent in S. pseudintermedius populations. CONCLUSIONS: Importantly, the data suggest that MDR MRSP evolved rapidly by the acquisition of a very limited number of MGEs and mutations, and that the use of many classes of antimicrobials may co-select for the spread and emergence of MDR and XDR strains. Antimicrobial stewardship will need to be comprehensive, encompassing human medicine and veterinary disciplines to successfully preserve antimicrobial efficacy