Experiences in deploying metadata analysis tools for institutional repositories

Current institutional repository software provides few tools to help metadata librarians understand and analyze their collections. In this article, we compare and contrast metadata analysis tools that were developed simultaneously, but independently, at two New Zealand institutions during a period of national investment in research repositories: the Metadata Analysis Tool (MAT) at The University of Waikato, and the Kiwi Research Information Service (KRIS) at the National Library of New Zealand. The tools have many similarities: they are convenient, online, on-demand services that harvest metadata using OAI-PMH; they were developed in response to feedback from repository administrators; and they both help pinpoint specific metadata errors as well as generating summary statistics. They also have significant differences: one is a dedicated tool wheres the other is part of a wider access tool; one gives a holistic view of the metadata whereas the other looks for specific problems; one seeks patterns in the data values whereas the other checks that those values conform to metadata standards. Both tools work in a complementary manner to existing Web-based administration tools. We have observed that discovery and correction of metadata errors can be quickly achieved by switching Web browser views from the analysis tool to the repository interface, and back. We summarize the findings from both tools' deployment into a checklist of requirements for metadata analysis tools

<i>In vivo</i> imaging of V_m and [Ca²⁺]_i dynamics in rat ventricles during sinus rhythm.

<p>(<b>A</b>) AP (red) and CaT (green) fluorescence signals taken from the 4×4-pixel white-square region highlighted in the top panel (left ventricle). (<b>B</b>) Normalized fluorescence intensity maps (colorbar shown) for V_m and [Ca²⁺]_i during sinus rhythm from the same heart; note the previously mentioned delay between V_m and [Ca²⁺]_i peaks (red arrow indicates electrical wave propagation direction). (<b>C</b>) AP (top traces) and CaT (bottom traces) fluorescence signals taken from three 4×4-pixel square regions from the left ventricle of another heart, showing varying motion artifact effects. Scale bar = 5 mm. For these images, blebbistatin was used to reduce, but not eliminate, the contribution of motion to the signals. For <b>B</b>, non-uniform dye-loading and motion artifact are the cause of signal quality heterogeneity.</p

Schematic illustration of multi-parametric imaging approach.

<p>(<b>A</b>) di-4-ANBDQPQ fluorescence in a Langendorff-perfused rat heart (sinus rhythm), excited with blue (blue LED, 470±10 nm filter), green (green LED, 540±12.5 nm filter) and red (red LED, 640±10 nm filter) wavelengths. These fluorescence signals (taken from the 4×4-pixel white-square region on the left-ventricle) were collected through a custom-made multi-band emission filter (F3 in <b>B</b>, <b>C</b>). The green trace ([Ca²⁺]_i) shows negligible emission changes when di-4-ANBDQPQ is excited at the excitation-isosbestic point. Scale bar = 5 mm. (<b>B</b>) Schematic outline of the imaging system, highlighting key components. Since only one camera is used, the system requires no challenging optical alignment. Excitation sources Ex1: red LED with a 640±10 nm filter (F1), Ex2: green LED with a 540±12.5 nm filter (F2). (<b>C</b>) Transmission spectrum of the custom multi-band emission filter that passes both V_m (Em1) and [Ca²⁺]_i (Em2) emitted fluorescence signals. F1 and F2 excitation filter spectra are shown as dashed curves. (<b>D</b>) Basic principle behind the single-camera multi-LED approach: During any frame exposure (occurring between the vertical dashed lines), the parameter being measured by the camera sensor is determined by the excitation source (either Ex1 or Ex2) that is switched on during that period. A sufficiently fast camera (compared to Em1 and Em2 signal dynamics), and interpolation between measured data points, provides simultaneous measures of multiple parameters, here V_m and [Ca²⁺]_i. For these images, blebbistatin was used to eliminate the contribution of motion to the signals.</p

<i>In vivo</i> rat whole-heart preparation.

<p>(<b>A</b>) A schematic of the rat cardiopulmonary bypass (CPB) circuit based on a standard pump circuit (EJV: right external jugular vein catheter, VR: venous reservoir, RP: roller pump, MO: miniature membrane oxygenator, FA: right femoral artery catheter, AA: ascending aorta catheter via right carotid artery). In CPB mode, blood is pumped from the EJV through the MO to the FA, epicted by arrows in the figure. Dye is injected through the AA catheter. (<b>B</b>) Whole-animal view of the preparation. (<b>C</b>) Zoomed-in view of the open chest, with the heart in clear view (EL: esophageal ECG lead, ET: endotracheal tube). (<b>D</b>) An example of RVP at 12 Hz to drop blood pressure (BP; red trace), after which dye was injected via the aortic root. The BP recovered soon after cessation of pacing. Immediately after loading as shown here, the BP increased reflecting the Frank-Starling effect of prolonged loading. The accompanying ECG (black trace) is also shown. (<b>E</b>) Zoomed-in view of the heart immediately after rhod-2(AM) injection demonstrating a fluorescent coronary angiogram. (<b>F</b>) Pooled data on heart rate (HR in ms), mean arterial BP (MAP in mmHg—right axis), as well as far field EKG parameters of PR, QRS, and QTc intervals (in ms) for immediately before (black) and at 5 minutes after loading with voltage dye (red).</p

Simultaneous imaging of V_m and [Ca²⁺]_i in a Langendorff-mode saline-perfused rat heart.

<p>(<b>A</b>) V_m (red) and [Ca²⁺]_i (green) fluorescence signals (camera signals on a 16-bit scale) taken from the 4×4-pixel white-square region on the left ventricle. (<b>B</b>) Normalized fluorescence intensity maps (colorbar shown) at progressive time points during sinus rhythm. The delay of the CaT relative to the AP peak (∼17 ms from transients in part <b>A</b>) is clearly visible. Scale bar = 5 mm. For these images, blebbistatin was used to eliminate the contribution of motion to the signals.</p