Observational studies and the difficult quest for causality: Lessons from vaccine effectiveness and impact studies

Although randomized placebo-controlled trials (RCT) are critical to establish efficacy of vaccines at the time of licensure, important remaining questions about vaccine effectiveness (VE) – used here to include individual-level measures and population-wide impact of vaccine programs - can only be answered once the vaccine is in use, from observational studies. However, such studies are inherently at risk for bias. Using a causal framework and illustrating with examples we review newer approaches to detecting and avoiding confounding and selection bias in three major classes of observational study design: cohort, case-control, and ecological studies. Studies of influenza VE, especially in seniors, are an excellent demonstration of the challenges of detecting and reducing such bias, and so we use influenza VE as a running example. We take a fresh look at the time-trend studies often dismissed as “ecological”. Such designs are the only observational study design that can measure the overall effect of a vaccination program (indirect (herd) as well as direct effects), and are in fact already an important part of the evidence base for several vaccines currently in use. Despite the great strides towards more robust observational study designs, challenges lie ahead for evaluating best practices for achieving robust unbiased results from observational studies. This is critical for evaluation of national and global vaccine program effectiveness

A Large-scale Analysis of the Marketplace Characteristics in Fiverr

Crowdsourcing platforms have become quite popular due to the increasing demand of human computation-based tasks. Though the crowdsourcing systems are primarily demand-driven like MTurk, supply-driven marketplaces are becoming increasingly popular. Fiverr is a fast growing supply-driven marketplace where the sellers post micro-tasks (gigs) and users purchase them for prices as low as $5. In this paper, we study the Fiverr platform as a unique marketplace and characterize the sellers, buyers and the interactions among them. We find that sellers are more appeasing in their interactions and try to woo their buyers into buying their gigs. There are many small tightly-knit communities existing in the seller-seller network who support each other. We also study Fiverr as a seller-driven marketplace in terms of sales, churn rates, competitiveness among various subcategories etc. and observe that while there are certain similarities with common marketplaces there are also many differences

Integrating emergency risk communication (ERC) into the public health system response: Systematic review of literature to aid formulation of the 2017 WHO Guideline for ERC policy and practice.

The World Health Organization (WHO) commissioned a systematic review of literature to facilitate evidence syntheses for the development of emergency risk communication (ERC) guidelines for its member states. The goal of this review was to integrate ERC best practices into governmental and non-governmental health systems for all emergencies of public health concern, by addressing three questions: (1) to identify best practices for the integration of ERC into national and international public health preparedness; (2) to identify mechanisms to establish effective intra-agency, inter-agency, and/or cross-jurisdictional information sharing; and (3) to identify methods to coordinate risk communication activities between responding agencies across organizations and levels of response. The review covered scientific and grey literature publications between January 2003 and February 2016, and searches were conducted in 17 English language electronic libraries besides Chinese, Portuguese and Spanish language databases. A mixed deductive-inductive process was used to synthesize findings across studies through identifying thematic areas. While 8,215 articles were initially retrieved, after a sequential screening process, the final evidence syntheses comprised of 21 articles for question (1) and 24 for questions (2) and (3) combined (due to overlap of themes). The confidence in findings was assessed by the Qualitative Evidence Syntheses (GRADE-CERQual) tool. PRISMA guidelines were followed to the extent possible given the limitations inherent to a review largely based on qualitative studies. The identified literature was very context-specific and referred to mechanisms, practices from the field, and recommendations that were derived from planning or response efforts implemented at the national or local levels in specific countries. Integration of ERC functions into public health emergency preparedness, planning and response activities was influenced by reforming components of the leadership structure when needed, modifying organizational factors, and nullifying restrictions (including amending laws/ regulations) that might have been an obstacle to the timely release of information. Exercises and trainings were recognized as effective strategies to identify the barriers and successes in this process of integration. Key elements to enhance information sharing and coordination across organizations included the creation of networks, task-forces and committees across disciplines, organizations and geographic areas. Engagement of local stakeholders was also important to guarantee the flow of information up and down the incident command system. On the whole, few empirical studies, especially from low- and middle-income countries, related to the WHO research questions, demonstrating the need for research in these areas. To facilitate an accurate identification of the gaps, the authors suggest integrating current findings with case studies across the WHO regions to better understand the specific evidence that is needed in practice across the multitude of ERC functions

Performance of the CMS Cathode Strip Chambers with Cosmic Rays

The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device in the CMS endcaps. Their performance has been evaluated using data taken during a cosmic ray run in fall 2008. Measured noise levels are low, with the number of noisy channels well below 1%. Coordinate resolution was measured for all types of chambers, and fall in the range 47 microns to 243 microns. The efficiencies for local charged track triggers, for hit and for segments reconstruction were measured, and are above 99%. The timing resolution per layer is approximately 5 ns

Performance and Operation of the CMS Electromagnetic Calorimeter

The operation and general performance of the CMS electromagnetic calorimeter using cosmic-ray muons are described. These muons were recorded after the closure of the CMS detector in late 2008. The calorimeter is made of lead tungstate crystals and the overall status of the 75848 channels corresponding to the barrel and endcap detectors is reported. The stability of crucial operational parameters, such as high voltage, temperature and electronic noise, is summarised and the performance of the light monitoring system is presented

Calibration of the CMS Drift Tube Chambers and Measurement of the Drift Velocity with Cosmic Rays

Peer reviewe

CMS Data Processing Workflows during an Extended Cosmic Ray Run

Peer reviewe

CMS physics technical design report : Addendum on high density QCD with heavy ions

Peer reviewe

Aligning the CMS Muon Chambers with the Muon Alignment System during an Extended Cosmic Ray Run

Peer reviewe