Teaching fundamental skills in Microsoft Excel to first-year students in quantitative analysis

Despite their technological savvy, most students entering university lack the necessary computer skills to succeed in a quantitative analysis course, in which they are often expected to input, analyze, and plot results of experiments without any previous formal education in Microsoft Excel or similar programs. This lack of formal education results in increased anxiety, students spending large amounts of time using the process of “trial and error” to complete the assignments, and detracts from the students’ learning of the chemistry. Microsoft Excel tutorials that were previously introduced have either been not specific to chemistry, require multiple assignments throughout the semester to acquire the necessary skills, or are designed for deprecated versions of the software. In this work, we present an argument for implementing a chemistry-specific, version-agnostic spreadsheet interactive laboratory exercise that uses basic, general chemistry concepts to have students explore and learn the computer skills that are necessary to succeed in a quantitative analysis course. Student feedback data indicate that students felt that the interactive spreadsheet lab allowed them to develop skills that they identified as necessary for success in the course as well as for their future careers.B.A. gratefully acknowledges the Boston University Grants for Undergraduate Teaching and Scholarship (GUTS) for their generous support. (Boston University)Accepted manuscrip

Polarización política en el Público americano

For more than two decades political scientists have discussed rising elite polarization in the United States, but the study of mass polarization did not receive comparable attention until fairly recently. This article surveys the literature on mass polarization. It begins with a discussion of the concept of polarization, then moves to a critical consideration of different kinds of evidence that have been used to study polarization, concluding that much of the evidence presents problems of inference that render conclusions problematic. The most direct evidence –citizens’ positions on public policy issues– shows little or no indication of increased mass polarization over the past two to three decades. Party sorting –an increased correlation between policy views and partisan identification– clearly has occurred, although the extent has sometimes been exaggerated. Geographic polarization –the hypothesized tenden- cy of like-minded people to cluster together– remains an open question. To date, there is no conclusive evidence that elite polarization has stimulated voters to polarize, on the one hand, or withdraw from politics, on the other.Por más de dos décadas los científicos políticos han discutido el aumento de la polarización de la élite en los Estados Unidos, pero el estudio de la polarización de las masas no recibió la misma atención sino hasta hace muy poco. Este artículo estudia la literatura acerca de la polarización de las masas. Comienza con una discusión del concepto de polarización, luego continúa con una consideración acerca de los diferentes tipos de evidencia que han sido utilizados para estudiar la polarización concluyendo que mucha de la evidencia presenta problemas de inferencia que proporciona conclusiones problemáticas. La evidencia más directa – la posición de los ciudadanos en temas de políticas públicas – muestra poca o ninguna indicación del aumento de la polarización de masas en las dos o tres últimas décadas. Claramente ha habido una clasificación de los partidos –una correlación creciente entre los puntos de vista políticos y la identificación de los adeptos–, aunque el alcance ha sido exagerado algunas veces. La polarización geográfica –la tendencia hipotética de personas afines a agruparse– permanece como un asunto abierto. Hasta la fecha, no hay una evidencia concluyente de que la polarización de la élite haya estimulado a los votantes por una parte, a polarizarse o por otra a retirarse de la política. &nbsp

Canonical Generations and the British Left: The Narrative Construction of the Miners’ Strike 1984–85

‘Generations’ have been invoked to describe a variety of social and cultural relationships, and to understand the development of self-conscious group identity. Equally, the term can be an applied label and politically useful construct; generations can be retrospectively produced. Drawing on the concept of ‘canonical generations’ – those whose experiences come to epitomise an event of historic and symbolic importance – this article examines the narrative creation and functions of ‘generations’ as collective memory shapes and re-shapes the desire for social change. Building a case study of the canonical role of the miners’ strike of 1984–85 in the narrative history of the British left, it examines the selective appropriation and transmission of the past in the development of political consciousness. It foregrounds the autobiographical narratives of activists who, in examining and legitimising their own actions and prospects, (re)produce a ‘generation’ in order to create a relatable and useful historical understanding

Quantitatively monitoring the resilience of patterned vegetation in the Sahel

Patterning of vegetation in drylands is a consequence of localized feedback mechanisms. Such feedbacks also determine ecosystem resilience—i.e. the ability to recover from perturbation. Hence, the patterning of vegetation has been hypothesized to be an indicator of resilience, that is, spots are less resilient than labyrinths. Previous studies have made this qualitative link and used models to quantitatively explore it, but few have quantitatively analysed available data to test the hypothesis. Here we provide methods for quantitatively monitoring the resilience of patterned vegetation, applied to 40 sites in the Sahel (a mix of previously identified and new ones). We show that an existing quantification of vegetation patterns in terms of a feature vector metric can effectively distinguish gaps, labyrinths, spots, and a novel category of spot–labyrinths at their maximum extent, whereas NDVI does not. The feature vector pattern metric correlates with mean precipitation. We then explored two approaches to measuring resilience. First we treated the rainy season as a perturbation and examined the subsequent rate of decay of patterns and NDVI as possible measures of resilience. This showed faster decay rates—conventionally interpreted as greater resilience—associated with wetter, more vegetated sites. Second we detrended the seasonal cycle and examined temporal autocorrelation and variance of the residuals as possible measures of resilience. Autocorrelation and variance of our pattern metric increase with declining mean precipitation, consistent with loss of resilience. Thus, drier sites appear less resilient, but we find no significant correlation between the mean or maximum value of the pattern metric (and associated morphological pattern types) and either of our measures of resilience

Post-thyroid FNA testing and treatment options: A synopsis of the National Cancer Institute Thyroid Fine Needle Aspiration State of the Science Conference

The National Cancer Institute (NCI) sponsored the NCI Thyroid Fine Needle Aspiration (FNA) State of the Science Conference on October 22–23, 2007 in Bethesda, MD. The 2-day meeting was accompanied by a permanent informational Web site and several on-line discussion periods between May 1 and December 15, 2007 ( http://thyroidfna.cancer.gov ). This document addresses follow-up procedures and therapeutic options for suggested diagnostic categories. Follow-up options for “nondiagnostic” and “benign” thyroid aspirates are given. The value of ultrasound examination in the follow-up of “nondiagnostic” and “benign” thyroid aspirates is discussed. Ultrasound findings requiring reaspiration or surgical resection are described as are the timing and length of clinical and ultrasonographic surveillance for cytologically “benign” nodules. Options for surgical intervention are given for the diagnostic categories of “atypical/borderline,” “follicular neoplasm,” “suspicious for malignancy” and “malignant” ( http://thyroidfna.cancer.gov/pages/info/agenda/ ). Diagn. Cytopathol. 2008;36:442–448. © 2008 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/58659/1/20832_ftp.pd

Bile acid and inflammation activate gastric cardia stem cells in a mouse model of barrett-like metaplasia

Esophageal adenocarcinoma (EAC) arises from Barrett esophagus (BE), intestinal-like columnar metaplasia linked to reflux esophagitis. In a transgenic mouse model of BE, esophageal overexpression of interleukin-1β phenocopies human pathology with evolution of esophagitis, Barrett-like metaplasia and EAC. Histopathology and gene signatures closely resembled human BE, with upregulation of TFF2, Bmp4, Cdx2, Notch1, and IL-6. The development of BE and EAC was accelerated by exposure to bile acids and/or nitrosamines, and inhibited by IL-6 deficiency. Lgr5+ gastric cardia stem cells present in BE were able to lineage trace the early BE lesion. Our data suggest that BE and EAC arise from gastric progenitors due to a tumor-promoting IL-1β-IL-6 signaling cascade and Dll1-dependent Notch signaling. © 2012 Elsevier Inc

Quantum Interferometric Optical Lithography: Exploiting Entanglement to Beat The Diffraction Limit

Classical, interferometric, optical lithography is diffraction limited to writing features of a size lambda/2 or greater, where lambda is the optical wavelength. Using nonclassical photon number states, entangled N at a time, we show that it is possible to write features of minimum size lambda/(2N) in an N-photon absorbing substrate. This result surpasses the usual classical diffraction limit by a factor of N. Since the number of features that can be etched on a two-dimensional surface scales inversely as the square of the feature size, this allows one to write a factor of N^2 more elements on a semiconductor chip. A factor of N = 2 can be achieved easily with entangled photon pairs generated from optical parametric downconversion. It is shown how to write arbitrary 2D patterns by using this method.Comment: 9 pages, 2 figure

Measurement of the Branching Fraction for B- --> D0 K*-

We present a measurement of the branching fraction for the decay B- --> D0 K*- using a sample of approximately 86 million BBbar pairs collected by the BaBar detector from e+e- collisions near the Y(4S) resonance. The D0 is detected through its decays to K- pi+, K- pi+ pi0 and K- pi+ pi- pi+, and the K*- through its decay to K0S pi-. We measure the branching fraction to be B.F.(B- --> D0 K*-)= (6.3 +/- 0.7(stat.) +/- 0.5(syst.)) x 10^{-4}.Comment: 7 pages, 1 postscript figure, submitted to Phys. Rev. D (Rapid Communications

Measurement of Branching Fraction and Dalitz Distribution for B0->D(*)+/- K0 pi-/+ Decays

We present measurements of the branching fractions for the three-body decays B0 -> D(*)-/+ K0 pi^+/-$and their resonant submodes$B0 -> D(*)-/+ K*+/- using a sample of approximately 88 million BBbar pairs collected by the BABAR detector at the PEP-II asymmetric energy storage ring. We measure: B(B0->D-/+ K0 pi+/-)=(4.9 +/- 0.7(stat) +/- 0.5 (syst)) 10^{-4} B(B0->D*-/+ K0 pi+/-)=(3.0 +/- 0.7(stat) +/- 0.3 (syst)) 10^{-4} B(B0->D-/+ K*+/-)=(4.6 +/- 0.6(stat) +/- 0.5 (syst)) 10^{-4} B(B0->D*-/+ K*+/-)=(3.2 +/- 0.6(stat) +/- 0.3 (syst)) 10^{-4} From these measurements we determine the fractions of resonant events to be : f(B0-> D-/+ K*+/-) = 0.63 +/- 0.08(stat) +/- 0.04(syst) f(B0-> D*-/+ K*+/-) = 0.72 +/- 0.14(stat) +/- 0.05(syst)Comment: 7 pages, 3 figures submitted to Phys. Rev. Let