Determination of the Rydberg Constant from the Emission Spectra of H and He+

Abstract In this experiment, the Rydberg constants for the hydrogen atom and He+ were determined by analysis of the emission spectra of Hand He, respectively, in comparison to the principal quantum numbers of each transition. Using both a hydrogen and then a helium atomic lamp attached to a 0.5 m grating spectrometer and a photomultiplier detector (PMT), a change in voltage detected by the PMT can be paired with a corresponding wavelength passing through the spectrometer from each emission peak in the visible to ultraviolet range. The peaks acquired from this change in voltage were analyzed to find their corresponding wavenumber value and then plotted versus the inverse square of the excited state quantum number (n2). The regression of this plot yields a linear relation that can then be used to calculate the Rydberg constant for H and He+. The values for H were determined to be 109 600 ± 300 cm-1 from the slope value and 109 640 ± 50 cm-1 from the y-intercept when the final state after radiative transition, n1= 2. The values derived from the He II spectrum for He+ were determined to be 111 000 ± 3000 cm-1 from the slope value, and 109 800 ± 700 cm-1 from the y-intercept value when the final state after radiative transition had an n1= 4

Rethinking Humanitarian Demining for Coalition Forces

When you first arrive as a member of the Multinational Brigade North (MNB(N)), you are full of promise. You know your team of highly trained professional soldiers will make a difference in the lives of those that live in BiH. Then it sets in. Your six-month tour of duty doesn’t allow you time to finish what you start. So what is it you can do to make a difference in only six months? This is the exact question that started the process of developing the National Guard Demining Initiative in BiH. This initiative was undertaken by the U.S. Army National Guard, an adjunct to the U.S. Armed Forces. There are multitudes of issues you can work to resolve in BiH. MNB(N) plays a supporting role in most of these, but we wanted to do something more. We wanted to bring a fresh idea to the area of operation (AO) that would make a significant impact on one of the many critical issues facing BiH. To make our choice, we focused on two key concerns: “What will have the biggest impact on the daily lives of the people?” and “What will instill confidence in the international community to speed up economic recovery?” We chose the issue of demining

Predicting Speech Acts in MOOC Forum Posts Using Conditional Random Fields

Massive Open Online Courses (MOOCs) have emerged as a way to reach large numbers of students by providing course materials as free online resources. The popularity of these courses has been reflected in high enrollment numbers, however it is unclear how successful MOOCs are at educating their students given their high attrition rates. One cause for this may be due to instructors' inability to manage the large number of students that enroll. While discussion forums are available for students to seek help, instructors are unable to monitor the large number of posts written in these forums. This study investigates the effectiveness of using machine learning models to classify posts into speech acts as a way to help instructors monitor these discussion forums. Speech acts describe the purpose of a post and may be indicative of common functions such as asking questions or raising issues. A linear classifier is compared against a conditional random field (CRF) classifier, which is able to leverage contextual information about the forum in order to make predictions. The results of this study find that CRFs outperform a simpler linear classifier, and this suggests that casting this prediction problem as a sequence labeling task is fruitful for predicting these speech acts, and automatically identifying posts of interest.Master of Science in Information Scienc

Варикозное расширение в системе суральных вен: диагностика, лечение, результаты

ВАРИКОЗНОЕ РАСШИРЕНИЕ ВЕН /ДИАГН /ТЕРКРОВЕНОСНЫХ СОСУДОВ БОЛЕЗНИРЕЦИДИВВЕНЫ /ПАТОЛО

Water-Use Data in the United States: Challenges and Future Directions

In the United States, greater attention has been given to developing water supplies and quantifying available waters than determining who uses water, how much they withdraw and consume, and how and where water use occurs. As water supplies are stressed due to an increasingly variable climate, changing land-use, and growing water needs, greater consideration of the demand side of the water balance equation is essential. Data about the spatial and temporal aspects of water use for different purposes are now critical to long-term water supply planning and resource management. We detail the current state of water-use data, the major stakeholders involved in their collection and applications, and the challenges in obtaining high-quality nationally consistent data applicable to a range of scales and purposes. Opportunities to improve access, use, and sharing of water-use data are outlined. We cast a vision for a world-class national water-use data product that is accessible, timely, and spatially detailed. Our vision will leverage the strengths of existing local, state, and federal agencies to facilitate rapid and informed decision-making, modeling, and science for water resources. To inform future decision-making regarding water supplies and uses, we must coordinate efforts to substantially improve our capacity to collect, model, and disseminate water-use data

Quantifying annual spatial consistency in chick-rearing seabirds to inform important site identification

Animal tracking has afforded insights into patterns of space use in numerous species and thereby informed area-based conservation planning. A crucial consideration when estimating spatial distributions from tracking data is whether the sample of tracked animals is representative of the wider population. However, it may also be important to track animals in multiple years to capture changes in distribution in response to varying environmental conditions. Using GPS-tracking data from 23 seabird species, we assessed the importance of multi-year sampling for identifying important sites for conservation during the chick-rearing period, when seabirds are most spatially constrained. We found a high degree of spatial overlap among distributions from different years in most species. Multi-year sampling often captured a significantly higher portion of reference distributions (based on all data for a population) than sampling in a single year. However, we estimated that data from a single year would on average miss only 5 % less of the full distribution of a population compared to equal-sized samples collected across three years (min: −0.3 %, max: 17.7 %, n = 23). Our results suggest a key consideration for identifying important sites from tracking data is whether enough individuals were tracked to provide a representative estimate of the population distribution during the sampling period, rather than that tracking necessarily take place in multiple years. By providing an unprecedented multi-species perspective on annual spatial consistency, this work has relevance for the application of tracking data to informing the conservation of seabirds

Purine Biosynthesis Metabolically Constrains Intracellular Survival of Uropathogenic Escherichia coli

The ability to de novo synthesize purines has been associated with the intracellular survival of multiple bacterial pathogens. Uropathogenic Escherichia coli (UPEC), the predominant cause of urinary tract infections, undergoes a transient intracellular lifestyle during which bacteria clonally expand into multicellular bacterial communities within the cytoplasm of bladder epithelial cells. Here, we characterized the contribution of the conserved de novo purine biosynthesis-associated locus cvpA-purF to UPEC pathogenesis. Deletion of cvpA-purF, or of purF alone, abolished de novo purine biosynthesis but did not impact bacterial adherence properties in vitro or in the bladder lumen. However, upon internalization by bladder epithelial cells, UPEC deficient in de novo purine biosynthesis was unable to expand into intracytoplasmic bacterial communities over time, unless it was extrachromosomally complemented. These findings indicate that UPEC is deprived of purine nucleotides within the intracellular niche and relies on de novo purine synthesis to meet this metabolic requirement

Dysregulation of PRMT5 in chronic lymphocytic leukemia promotes progression with high risk of Richter's transformation

: Richter's Transformation (RT) is a poorly understood and fatal progression of chronic lymphocytic leukemia (CLL) manifesting histologically as diffuse large B-cell lymphoma. Protein arginine methyltransferase 5 (PRMT5) is implicated in lymphomagenesis, but its role in CLL or RT progression is unknown. We demonstrate herein that tumors uniformly overexpress PRMT5 in patients with progression to RT. Furthermore, mice with B-specific overexpression of hPRMT5 develop a B-lymphoid expansion with increased risk of death, and Eµ-PRMT5/TCL1 double transgenic mice develop a highly aggressive disease with transformation that histologically resembles RT; where large-scale transcriptional profiling identifies oncogenic pathways mediating PRMT5-driven disease progression. Lastly, we report the development of a SAM-competitive PRMT5 inhibitor, PRT382, with exclusive selectivity and optimal in vitro and in vivo activity compared to available PRMT5 inhibitors. Taken together, the discovery that PRMT5 drives oncogenic pathways promoting RT provides a compelling rationale for clinical investigation of PRMT5 inhibitors such as PRT382 in aggressive CLL/RT cases