Quantifying discrepancies in opinion spectra from online and offline networks

Online social media such as Twitter are widely used for mining public opinions and sentiments on various issues and topics. The sheer volume of the data generated and the eager adoption by the online-savvy public are helping to raise the profile of online media as a convenient source of news and public opinions on social and political issues as well. Due to the uncontrollable biases in the population who heavily use the media, however, it is often difficult to measure how accurately the online sphere reflects the offline world at large, undermining the usefulness of online media. One way of identifying and overcoming the online-offline discrepancies is to apply a common analytical and modeling framework to comparable data sets from online and offline sources and cross-analyzing the patterns found therein. In this paper we study the political spectra constructed from Twitter and from legislators' voting records as an example to demonstrate the potential limits of online media as the source for accurate public opinion mining.Comment: 10 pages, 4 figure

PILOTs: What Are They and Are They Affected by Institutional and/or Economic Constraints? The Case of Wisconsin Municipalities

Following the rise of tax and expenditure limitations in the 1970s, scholars have focused on assessing the effects of these limitations on local government fiscal outcomes. One key takeaway has been local governments’ decreasing reliance on property taxes and increased use of nontax revenue sources, in particular fees and changes. This study builds on this work by focusing on a particular type of fee—that is, payments in lieu of taxes (PILOTs). We find that, in Wisconsin, revenues received by municipalities from two PILOTs programs are affected quite differently. The extent to which the economy, municipal fiscal condition, tax and expenditure limits, and community characteristics affect PILOTs’ revenues depends on the extent to which the municipality can manipulate the payment structure

The Stream-Stream Collision after the Tidal Disruption of a Star Around a Massive Black Hole

A star can be tidally disrupted around a massive black hole. It has been known that the debris forms a precessing stream, which may collide with itself. The stream collision is a key process determining the subsequent evolution of the stellar debris: if the orbital energy is efficiently dissipated, the debris will eventually form a circular disk (or torus). In this paper, we have numerically studied such stream collision resulting from the encounter between a 10^6 Msun black hole and a 1 Msun normal star with a pericenter radius of 100 Rsun. A simple treatment for radiative cooling has been adopted for both optically thick and thin regions. We have found that approximately 10 to 15% of the initial kinetic energy of the streams is converted into thermal energy during the collision. The angular momentum of the incoming stream is increased by a factor of 2 to 3, and such increase, together with the decrease in kinetic energy, significantly helps the circularization process. Initial luminosity burst due to the collision may reach as high as 10^41 erg/sec in 10^4 sec, after which the luminosity increases again (but slowly this time) to a steady value of a few 10^40 erg/sec in a few times of 10^5 sec. The radiation from the system is expected to be close to Planckian with effective temperature of \~10^5K.Comment: 19 pages including 12 figures; Accepted for publication in Ap

Jamming transition in a highly dense granular system under vertical vibration

The dynamics of the jamming transition in a three-dimensional granular system under vertical vibration is studied using diffusing-wave spectroscopy. When the maximum acceleration of the external vibration is large, the granular system behaves like a fluid, with the dynamic correlation function G(t) relaxing rapidly. As the acceleration of vibration approaches the gravitational acceleration g, the relaxation of G(t) slows down dramatically, and eventually stops. Thus the system undergoes a phase transition and behaves like a solid. Near the transition point, we find that the structural relaxation shows a stretched exponential behavior. This behavior is analogous to the behavior of supercooled liquids close to the glass transition.Comment: 5 pages, 5 figures, accepted by Phys. Rev.

Comments on "Entropy of 2D Black Holes from Counting Microstates"

In a recent letter, Cadoni and Mignemi proposed a formulation for the statistical computation of the 2D black holes entropy. We present a criticism about their formulation.Comment: 5 pages, Latex, no figure

Calibration of second-order correlation functions for non-stationary sources with a multi-start multi-stop time-to-digital converter

A novel high-throughput second-order-correlation measurement system is developed which records and makes use of all the arrival times of photons detected at both start and stop detectors. This system is suitable particularly for a light source having a high photon flux and a long coherence time since it is more efficient than conventional methods by an amount equal to the product of the count rate and the correlation time of the light source. We have used this system in carefully investigating the dead time effects of detectors and photon counters on the second-order correlation function in the two-detector configuration. For a non-stationary light source, distortion of original signal was observed at high photon flux. A systematic way of calibrating the second-order correlation function has been devised by introducing a concept of an effective dead time of the entire measurement system.Comment: 7 pages, 6 figure

A Spectral Line Survey from 138.3 to 150.7 GHZ toward Orion-KL

We present the results of a spectral line survey from 138.3 to 150.7 GHz toward Orion-KL. The observations were made using the 14 m radio telescope of Taeduk Radio Astronomy Observatory. Typical system temperatures were between 500 and 700 K, with the sensitivity between $0.02 - 0.06$ K in units of $\rm T_A^*$. A total of 149 line spectra are detected in this survey. Fifty lines have been previously reported, however we find 99 new detections. Among these new lines, 32 are `unidentified', while 67 are from molecular transitions with known identifications. There is no detection of H or He recombination lines. The identified spectra are from a total of 16 molecular species and their isotopic variants. In the range from 138.3 to 150.7 GHz, the strongest spectral line is the J=3-2 transition of CS molecule, followed by transitions of the $\rm H_2CO$, $\rm CH_3OH$, $\rm CH_3CN$, and $\rm SO_2$. Spectral lines from the large organic molecules such as $\rm CH_3OH$, $\rm CH_3OCH_3$, $\rm HCOOCH_3$, $\rm C_2H_5CN$ and $\rm CH_3CN$ are prominent; with 80 % of the identified lines arising from transitions of these molecules. The rotational temperatures and column densities are derived using the standard rotation diagram analysis for $\rm CH_3OH$ ($\rm ^{13}CH_3OH$), $\rm HCOOCH_3$, $\rm CH_3CN$ and $\rm SO_2$ with $\rm 10\sim 270 K$ and $\rm 0.2\sim 20\times 10^{15} cm^{-2}$. These estimates are fairly comparable to the values for the same molecule in other frequency regions by other studies.Comment: 10 figures, 2 tex files for a manuscript and tables, accepted to Ap

Aggregate Plaque Volume by Coronary Computed Tomography Angiography Is Superior and Incremental to Luminal Narrowing for Diagnosis of Ischemic Lesions of Intermediate Stenosis Severity

ObjectivesThis study examined the performance of percent aggregate plaque volume (%APV), which represents cumulative plaque volume as a function of total vessel volume, by coronary computed tomography angiography (CTA) for identification of ischemic lesions of intermediate stenosis severity.BackgroundCoronary lesions of intermediate stenosis demonstrate significant rates of ischemia. Coronary CTA enables quantification of luminal narrowing and %APV.MethodsWe identified 58 patients with intermediate lesions (30% to 69% diameter stenosis) who underwent invasive angiography and fractional flow reserve. Coronary CTA measures included diameter stenosis, area stenosis, minimal lumen diameter (MLD), minimal lumen area (MLA) and %APV. %APV was defined as the sum of plaque volume divided by the sum of vessel volume from the ostium to the distal portion of the lesion. Fractional flow reserve ≤0.80 was considered diagnostic of lesion-specific ischemia. Area under the receiver operating characteristic curve and net reclassification improvement (NRI) were also evaluated.ResultsTwenty-two of 58 lesions (38%) caused ischemia. Compared with nonischemic lesions, ischemic lesions had smaller MLD (1.3 vs. 1.7 mm, p = 0.01), smaller MLA (2.5 vs. 3.8 mm2, p = 0.01), and greater %APV (48.9% vs. 39.3%, p < 0.0001). Area under the receiver operating characteristic curve was highest for %APV (0.85) compared with diameter stenosis (0.68), area stenosis (0.66), MLD (0.75), or MLA (0.78). Addition of %APV to other measures showed significant reclassification over diameter stenosis (NRI 0.77, p < 0.001), area stenosis (NRI 0.63, p = 0.002), MLD (NRI 0.62, p = 0.001), and MLA (NRI 0.43, p = 0.01).ConclusionsCompared with diameter stenosis, area stenosis, MLD, and MLA, %APV by coronary CTA improves identification, discrimination, and reclassification of ischemic lesions of intermediate stenosis severity

Predictors of perioperative blood loss in total joint arthroplasty.

UNLABELLED: UPDATE The print version of this article has errors that have been corrected in the online version of this article. In the Materials and Methods section, the sentence that reads as During the study period, our institution offered preoperative autologous blood donation to all patients who were scheduling for total joint arthroplasty with a hemoglobin level of no less than 11 mg/dL or a hematocrit level of at least 33%. in the print version now reads as During the study period, our institution offered preoperative autologous blood donation to all patients who were scheduling for total joint arthroplasty with a hemoglobin level of no less than 11 g/dL or a hematocrit level of at least 33%. in the online version. In Table III, the footnote that reads as The values are given as the estimate and the standard error in milligrams per deciliter. in the print version now reads as The values are given as the estimate and the standard error in grams per deciliter. in the online version. BACKGROUND: Despite advances in surgical and anesthetic techniques, lower-extremity total joint arthroplasty is associated with considerable perioperative blood loss. As predictors of perioperative blood loss and allogenic blood transfusion have not yet been well defined, the purpose of this study was to identify clinical predictors for perioperative blood loss and allogenic blood transfusion in patients undergoing total joint arthroplasty. METHODS: From 2000 to 2008, all patients undergoing unilateral primary total hip or knee arthroplasty who met the inclusion criteria were enrolled in the study. Perioperative blood loss was calculated with use of a previously validated formula. The predictors of perioperative blood loss and allogenic blood transfusion were identified in a multivariate analysis. RESULTS: Eleven thousand three hundred and seventy-three patients who underwent total joint arthroplasty, including 4769 patients who underwent total knee arthroplasty and 6604 patients who underwent total hip arthroplasty, were evaluated. Multivariate analysis indicated that an increase in blood loss was associated with being male (263.59 mL in male patients who had undergone total hip arthroplasty and 233.60 mL in male patients who had undergone total knee arthroplasty), a Charlson Comorbidity Index of \u3e3 (293.99 mL in patients who had undergone total hip arthroplasty and 167.96 mL in patients who had undergone total knee arthroplasty), and preoperative autologous blood donation (593.51 mL in patients who had undergone total hip arthroplasty and 592.30 mL in patients who had undergone total knee arthroplasty). In patients who underwent total hip arthroplasty, regional anesthesia compared with general anesthesia reduced the amount of blood loss. The risk of allogenic blood transfusion increased with the amount of blood loss in the patients who underwent total hip arthroplasty (odds ratio, 1.43 [95% confidence interval, 1.40 to 1.46]) and the patients who underwent total knee arthroplasty (odds ratio, 1.47 [95% confidence interval, 1.42 to 1.51]), but the risk of blood transfusion increased with the Charlson Comorbidity Index only in patients who underwent total knee arthroplasty (odds ratio, 3.2 [95% confidence interval, 1.99 to 5.15]). The risk of allogenic blood transfusion decreased with preoperative autologous blood donation in patients who underwent total hip arthroplasty (odds ratio, 0.01 [95% confidence interval, 0.01 to 0.02]) and patients who underwent total knee arthroplasty (odds ratio, 0.02 [95% confidence interval, 0.01 to 0.03]). CONCLUSIONS: This study identified some clinical predictors for blood loss in patients undergoing total joint arthroplasty that we believe can be used for implementing more effective blood conservation strategies. LEVEL OF EVIDENCE: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence

Smart-Cut Layer Transfer of Single-Crystal SiC Using Spin-on-Glass

The authors demonstrate “smart-cut”-type layer transfer of single-crystal silicon carbide (SiC) by using spin-on-glass (SoG) as an adhesion layer. Using SoG as an adhesion layer is desirable because it can planarize the surface, facilitate an initial low temperature bond, and withstand the thermal stresses at high temperature where layer splitting occurs (800–900 °C). With SoG, the bonding of wafers with a relatively large surface roughness of 7.5–12.5 Å rms can be achieved. This compares favorably to direct (fusion) wafer bonding, which usually requires extremely low roughness (\u3c2 Å rms), typically achieved using chemical mechanical polishing (CMP) after implantation. The higher roughness tolerance of the SoG layer transfer removes the need for the CMP step, making the process more reliable and affordable for expensive materials like SiC. To demonstrate the reliability of the smart-cut layer transfer using SoG, we successfully fabricated a number of suspended MEMS structures using this technology