Evolution of Conversations in the Age of Email Overload

Email is a ubiquitous communications tool in the workplace and plays an important role in social interactions. Previous studies of email were largely based on surveys and limited to relatively small populations of email users within organizations. In this paper, we report results of a large-scale study of more than 2 million users exchanging 16 billion emails over several months. We quantitatively characterize the replying behavior in conversations within pairs of users. In particular, we study the time it takes the user to reply to a received message and the length of the reply sent. We consider a variety of factors that affect the reply time and length, such as the stage of the conversation, user demographics, and use of portable devices. In addition, we study how increasing load affects emailing behavior. We find that as users receive more email messages in a day, they reply to a smaller fraction of them, using shorter replies. However, their responsiveness remains intact, and they may even reply to emails faster. Finally, we predict the time to reply, length of reply, and whether the reply ends a conversation. We demonstrate considerable improvement over the baseline in all three prediction tasks, showing the significant role that the factors that we uncover play, in determining replying behavior. We rank these factors based on their predictive power. Our findings have important implications for understanding human behavior and designing better email management applications for tasks like ranking unread emails.Comment: 11 page, 24th International World Wide Web Conferenc

Surface wave non-reciprocity via time-modulated metamaterials

We investigate how Rayleigh waves interact with time-modulated resonators located on the free surface of a semi-infinite elastic medium. We begin by studying the dynamics of a single resonator with time-modulated stiffness, we evaluate the accuracy of an analytical approximation of the resonator response and identify the parameter ranges in which its behavior remains stable. Then, we develop an analytical model to describe the interaction between surface waves and an array of resonators with spatio-temporally modulated stiffness. By combining our analytical models with full-scale numerical simulations, we demonstrate that spatio-temporal stiffness modulation of this elastic metasurface leads to the emergence of non-reciprocal features in the Rayleigh wave spectrum. Specifically, we show how the frequency content of a propagating signal can be filtered and converted when traveling through the modulated medium, and illustrate how surface-to-bulk wave conversion plays a role in these phenomena. Throughout this article, we indicate bounds of modulation parameters for which our theory is reliable, thus providing guidelines for future experimental studies on the topic

Wavepacket instability in a rectangular porous channel uniformly heated from below

This paper is aimed to investigate the transition to absolute instability in a porous layer with horizontal throughflow. The importance of this analysis is due to the possible experimental failure to detect growing perturbations which are localised in space and which may be convected away by the throughflow. The instability of the uniform flow in a horizontal rectangular channel subject to uniform heating from below and cooled from above is studied. While the lower wall is modelled as an impermeable isoflux plane, the upper wall is assumed to be impermeable and imperfectly conducting, so that a Robin temperature condition with a given Biot number is prescribed. The sidewalls are assumed to be adiabatic and impermeable. The basic state considered here is a stationary parallel flow with a vertical uniform temperature gradient, namely the typical configuration describing the Darcy–Bénard instability with throughflow. The linear instability of localised wavepackets is analysed, thus detecting the parametric conditions for the transition to absolute instability. The absolute instability is formulated through an eigenvalue problem based on an eighth–order system of ordinary differential equations. The solution is sought numerically by utilising the shooting method. The threshold to absolute instability is detected versus the Péclet number associated with the basic flow rate along the channel

COPD in young patients: A pre-specified analysis of the four-year trial of tiotropium (UPLIFT)

SummaryWhilst recent large-scale studies have provided much evidence on the natural history and therapeutic response in patients with chronic obstructive pulmonary disease (COPD), relatively little is known about the effect in younger patients.We report a pre-specified post-hoc analysis of 356 patients with COPD ≤ 50 years old from the four year randomised, double blind placebo controlled Understanding Potential Long Term Impact on Function with Tiotropium (UPLIFT) trial. Inclusion criteria included a post-bronchodilator forced expiratory volume in 1 s (FEV1) of ≤70%, FEV1/FVC < 0.70, age ≥40 years, and smoking history of ≥10 pack years.Younger patients had a mean FEV1 of 1.24 L (39% predicted) and an impaired health-related quality of life (St. George’s Respiratory Questionnaire (SGRQ)) compared to the entire UPLIFT population. There were 40.2% women and 51.1% current smokers in the younger age group. Tiotropium was associated with a sustained improvement in spirometry and SGRQ. Mean decline in post-bronchodilator FEV1 was 58 ml/year (placebo) vs. 38 ml/year (tiotropium) (p = 0.01). Corresponding values for pre-bronchodilator FEV1 were 41 ml/year (placebo) compared with 34 ml/year (tiotropium) (p = 0.34). The hazard ratio (95%CI) for an exacerbation in the younger age group was 0.87(0.68, 1.13)). The rate of exacerbations was reduced by tiotropium (rate ratio (95%CI) = 0.73(0.56, 0.95)).Tiotropium resulted in sustained bronchodilation, improved quality of life, and a decreased exacerbation rate in younger patients. Tiotropium also resulted in a significant reduction in the decline in post-bronchodilator FEV1, suggesting possible disease modification by tiotropium in younger patients with COPD

Tiotropium reduces risk of exacerbations irrespective of previous use of inhaled anticholinergics in placebo-controlled clinical trials

Data have highlighted the potential bias introduced by withdrawal of inhaled corticosteroids at randomization in chronic obstructive pulmonary disease trials examining inhaled corticosteroids. Analyses were conducted to determine whether this was true of inhaled anticholinergic withdrawal in tiotropium trials.status: publishe

First report of Rice stripe necrosis virus infecting rice in Sierra Leone

While Rice stripe necrosis virus (RSNV, Benyvirus, Benyviridae) has been reported on rice plants on two continents, little is known about the diversity of this multipartite virus which is transmitted by the plasmodiophorid protist Polymyxa graminis. First identified in 1983 in the Côte d´Ivoire (Fauquet & Thouvenel, 1983), the disease had previously been observed in Sierra Leone without formal identification of the causal agent (Buddenhagen, pers. comm.). Later, the virus was reported in South and Central America (Colombia, Ecuador, Panama and Brazil) causing up to 40% yield losses (Morales et al., 1999). Recently, RSNV was identified for the first time in several African countries including Burkina Faso (Sérémé et al., 2014), Benin (Oludare et al., 2015) and Mali (Decroës et al., 2017) suggesting a re-emergence of the virus in Africa.In 2019, symptoms of leaf-crinkling and stripe necrosis were observed on a rice plant from the Bo District in Sierra Leone (Fig. 1). Leaf samples were analysed by serological and molecular methods to confirm the presence of RSNV in Sierra Leone. RSNV was detected by plate-trapped antibody (PTA)- ELISA using a polyclonal antiserum against RSNV (Fauquet & Thouvenel, 1983).The presence of the virus was confirmed after total RNA extraction using 0.05 g of leaves and the RNeasy Plant Mini Kit (Qiagen) and RT-PCR amplification (10 U/μl M-MLV-reverse transcriptase, Promega; 10 U/μl Dynazyme, Finnzyme) as described previously (Sérémé et al., 2014, Oludare et al., 2015) with primers RSNV1-2901F 5′-TGAATTTGGTGCTCTCTTG-3′ / RSNV1-3827R 5′-TGTGGCGTTTCCAGACCTAAA-3´ and RSNV2-5´ 5´-TATCACTACTGACGAATTCCACCTAC-3´ / RSNV2-1223R 5´-AATCTGCGGCCTGTTTTGTA-3´. Specific amplicons, 926 and 1241 nt in length, were generated corresponding to sequences in the helicase domain and the coat protein (CP) genes on RSNV RNA 1 and RNA 2, respectively. The amplicons were sequenced directly and the sequences deposited in GenBank (Accession Nos. MN750254 and MN750255, respectively).The helicase sequence obtained from the Sierra Leone RSNV isolate showed 1.8-7.3% genetic distance with those from South America (EU099844.3, MG792544, MG792545, MG792546) and only 1.4-2.2% with those from Africa (KP099623, MF115599, MF115600, MF115601, MF115602, MF115603, MK170452, MK170453). The phylogenetic analysis based on the helicase domain included the sequence obtained from the Sierra Leone within a cluster represented by RSNV from South America and West Africa (Fig. 2a). In contrast, the CP sequence from the Sierra Leone RSNV isolate revealed an unexpected genetic differentiation as compared to all the other sequences from South America (5.6%; NC_038774) or Africa (5.2-6.5%; LK023710, MF115604, MF115605, MF115606, MF115607, MF115608, MK170454, MK170455). Interestingly, the CP sequence from Sierra Leone is located at a basal position in the phylogeny (Fig. 2b).To our knowledge, this is the first confirmed report of RSNV in Sierra Leone. Further studies are needed to assess the molecular and biological diversity of RSNV, the spatial distribution and the incidence of this re-emerging rice disease in Africa.Fil: Tucker, M. J.. Sierra Leone Agricultural Research Institute; Sierra LeonaFil: Giovani Celli, Marcos Giovani. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Unidad de Fitopatología y Modelización Agrícola - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Unidad de Fitopatología y Modelización Agrícola; ArgentinaFil: Conteh, A. B.. Sierra Leone Agricultural Research Institute; Sierra LeonaFil: Taylor, D. R.. Sierra Leone Agricultural Research Institute; Sierra LeonaFil: Hebrard, Andrés. Centre National de la Recherche Scientifique. Institut de Recherche pour le Développement; FranciaFil: Poulicard, N.. Centre National de la Recherche Scientifique. Institut de Recherche pour le Développement; Franci