A perpetual switching system in pulmonary capillaries

Of the 300 billion capillaries in the human lung, a small fraction meet normal oxygen requirements at rest, with the remainder forming a large reserve. The maximum oxygen demands of the acute stress response require that the reserve capillaries are rapidly recruited. To remain primed for emergencies, the normal cardiac output must be parceled throughout the capillary bed to maintain low opening pressures. The flow-distributing system requires complex switching. Because the pulmonary microcirculation contains contractile machinery, one hypothesis posits an active switching system. The opposing hypothesis is based on passive switching that requires no regulation. Both hypotheses were tested ex vivo in canine lung lobes. The lobes were perfused first with autologous blood, and capillary switching patterns were recorded by videomicroscopy. Next, the vasculature of the lobes was saline flushed, fixed by glutaraldehyde perfusion, flushed again, and then reperfused with the original, unfixed blood. Flow patterns through the same capillaries were recorded again. The 16-min-long videos were divided into 4-s increments. Each capillary segment was recorded as being perfused if at least one red blood cell crossed the entire segment. Otherwise it was recorded as unperfused. These binary measurements were made manually for each segment during every 4 s throughout the 16-min recordings of the fresh and fixed capillaries (>60,000 measurements). Unexpectedly, the switching patterns did not change after fixation. We conclude that the pulmonary capillaries can remain primed for emergencies without requiring regulation: no detectors, no feedback loops, and no effectors-a rare system in biology. NEW & NOTEWORTHY The fluctuating flow patterns of red blood cells within the pulmonary capillary networks have been assumed to be actively controlled within the pulmonary microcirculation. Here we show that the capillary flow switching patterns in the same network are the same whether the lungs are fresh or fixed. This unexpected observation can be successfully explained by a new model of pulmonary capillary flow based on chaos theory and fractal mathematics

Perioperative hair removal in the 21st century: utilizing an innovative vacuum-assisted technology to safely expedite hair removal before surgery.

Background: Perioperative hair removal using clippers requires lengthy cleanup to remove loose hairs contaminating the operative field. We compared the amount of hair debris and associated microbiologic contamination produced during clipping of surgical sites using standard surgical clippers (SSC) or clippers fitted with a vacuum-assisted hair collection device (SCVAD). Methods: Trained nurses conducted bilateral hair clipping of the chest and groin of 18 male subjects using SSC or SCVAD. Before and during clipping, measurements of particulate matter and bacterial contamination were evaluated on settling plates placed next to each subject’s chest and groin. Skin condition after clipping and total clipping/cleanup times were compared between SSC and SCVAD. Results: The microbial burden recovered from residual hair during cleanup in the SSC group was 3.9 log10 CFU and 4.6 log10 CFU from respective, chest, and groin areas. Use of the SCVAD resulted in a significant (P < .001) reduction in both residual hair and microbial contamination within the operative field compared with SSC. Conclusions: Use of SCVAD resulted in significant (P< .001) reduction in total time required to clip and clean up residual hair contaminating the operative field compared with standard practice (ie, SSC), eliminating the need to physically remove dispersed hairs, which can harbor a significant microbial burden, from within the operative field

Jove i participatiu : requisits del nou model de transmissió cultural

La imitació com a mètode d'aprenentatge humà mai ha estat un procés simple. L'evolució cultural de l'espècie humana que d'ella es deriva segueix arrelada a una actitud selectiva -els models escollits es caracteritzen per ser individus amb prestigi-, però sembla ser que aquesta reputació ja no recau en els mateixos de sempre. Mitjançant un estudi de camp amb els Tsimane' -un grup ètnic bolivià-, s'ha vist que el lideratge ha passat a mans dels més joves, tenint aquests un alt nivell educatiu i una forta vinculació amb el treball comunitari.La imitación como método de aprendizaje humano nunca ha sido un proceso simple. La evolución cultural de la especie humana que de ella se deriva sigue arraigada a una actitud selectiva -los modelos escogidos se caracterizan por ser individuos con prestigio-, pero parece ser que esa reputación ya no recae en los mismos de siempre. Mediante un estudio de campo con los Tsimane -un grupo étnico boliviano-, se ha visto que el liderazgo ha pasado a manos de los más jóvenes, teniendo éstos un alto nivel educativo y una fuerte vinculación con el trabajo comunitario.Imitation as a method of human learning has never been a simple process. The cultural evolution of the human species based on this method continues to be established in a selective attitude - the selected models are characterized for being prestigious individuals. However, it seems to be that this prestige is no longer conferred to the same models as before. A field study with the Tsimane' - an ethnic group in Bolivia-, has demonstrated that the leadership has moved to the hands of the youngest, who have a high educational level and strong links with community work

Teaching Tip: Experiential and Peer Learning in an IT Project Management Course: Flipped Classroom, Concept Maps, and Project Dojos

In this teaching tip, we describe our approach to elevating the quality of group work in an information technology (IT) project management course by implementing three practices of experiential and peer learning that work more effectively when combined. The first practice addresses slacking in group work by applying a flipped classroom style that allowed students to acquire individual skills and then reflect on those skills in pairs with the instructor’s support and supervision. The second practice uses concept maps to deepen the understanding of relevant tools and concepts and to foster the synthesis of topics and big-picture composition. The third practice addresses the prevalent divide-and-conquer culture in group work, in which we structured intense work sessions in the classroom with instructor guidance and supervision to complete group projects. In this proposed framework, the work sessions mimic the concept of a dojo that is widely used in martial arts. Even though it is still rare in information systems (IS) education, this concept has been applied in the context of software engineering and IT projects—both in higher education and in industry for employee training. The three-pronged approach described in this paper is intended to provide students with an experiential learning experience that transforms group work from an inefficient process to an intense and focused short-term period of work. Based on our observations and student feedback, the approach is effective and can positively impact group experience by countering common pitfalls, such as the divide-and-conquer mentality and social loafing, and by enhancing peer learning efficacy. We also provide suggestions for its application in the context of an IT project management course

Three Perspectives of Planning, Implementation, and Consistency in Instructional Coaching

School administrators are choosing or required to implement instructional coaching on their campuses to improve student-learning opportunities. The school community must be aware that effective instructional coaching is job embedded, encourages teachers to become reflective practitioners, and requires time to commit to the implementation. School administrators must support instructional coaches by ensuring there is significant time allotted to provide coaches time in the classroom to observe, provide feedback, and support classroom teachers in their practice and reflection. Instructional coaches build trust and rapport with the instructional staff by implementing best-practice protocols, providing feedback, and planning the next steps. The instructional staff must be disposed to take the feedback and be willing to implement best practices and reflect upon the process. This article reflects each author’s personal experiences in their roles as a school administrator, instructional coach, and classroom teacher with the distinct focus on instructional coaching from the practitioners’ diverse perspectives. Current research on instructional coaching is examined and discussed. Best practices for classroom implementation of instructional coaching are reviewed. The article concludes that implementing instructional coaching in a school setting requires the school administrator to engage all stakeholders to understand the diverse perspectives of the individuals involved in the process. Implementing instructional coaching in a school setting must include the instructional process and student achievement as priorities