Observed Mobility Changes Research Articles

The impact of dengue illness on social distancing and caregiving behavior.

BackgroundHuman mobility among residential locations can drive dengue virus (DENV) transmission dynamics. Recently, it was shown that individuals with symptomatic DENV infection exhibit significant changes in their mobility patterns, spending more time at home during illness. This change in mobility is predicted to increase the risk of acquiring infection for those living with or visiting the ill individual. It has yet to be considered, however, whether social contacts are also changing their mobility, either by socially distancing themselves from the infectious individual or increasing contact to help care for them. Social, or physical, distancing and caregiving could have diverse yet important impacts on DENV transmission dynamics; therefore, it is necessary to better understand the nature and frequency of these behaviors including their effect on mobility.Methodology and principal findingsThrough community-based febrile illness surveillance and RT-PCR infection confirmation, 67 DENV positive (DENV+) residents were identified in the city of Iquitos, Peru. Using retrospective interviews, data were collected on visitors and home-based care received during the illness. While 15% of participants lost visitors during their illness, 22% gained visitors; overall, 32% of all individuals (particularly females) received visitors while symptomatic. Caregiving was common (90%), particularly caring by housemates (91%) and caring for children (98%). Twenty-eight percent of caregivers changed their behavior enough to have their work (and, likely, mobility patterns) affected. This was significantly more likely when caring for individuals with low “health-related quality of well-being” during illness (Fisher’s Exact, p = 0.01).Conclusions/SignificanceOur study demonstrates that social contacts of individuals with dengue modify their patterns of visitation and caregiving. The observed mobility changes could impact a susceptible individual’s exposure to virus or a presymptomatic/clinically inapparent individual’s contribution to onward transmission. Accounting for changes in social contact mobility is imperative in order to get a more accurate understanding of DENV transmission.

Proton-Induced Mobility Degradation in FinFETs With Stressor Layers and Strained SOI Substrates

Proton irradiation effects on fin-type field effect transistors (FinFETs) are examined from the viewpoint of their electrical-performance parameter of mobility. They are fabricated with various types of combination of strain/stress techniques to control their mobilities. The base stress level is globally modified by means of nonstrained or strained silicon-on-insulator wafers. Some process splits, additionally, receive a local strain tuning with a contact-etch-stop layer (CESL). Both <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n</i> - and <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p</i> -type FinFETs are evaluated. A 60-MeV proton irradiation with a fluence of 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</sup> p/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> leads to mobility changes for wide-fin samples: degradation for <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n</i> -type and enhancement for <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p</i> -type. These mobility variations can be explained with a change in the number of charged interface traps at the Si and buried-oxide interface. Narrow-fin devices exhibit mobility changes unnoticeable statistically. A comparison with previous studies indicates an elevated source/drain structure plays a role in this mobility preservation. Although the mobility is kept intact in the narrow-fin samples, a close investigation based on a two channel-component model can reveal noticeable mobility variations at a component level. In this study, observed mobility changes are complex depending on the adopted stress techniques as well as process parameters and cannot be explained by the stress levels simply.

Real-Time Dynamics Changes of Helix 8 upon Phosphorylation of Rhodopsin and Arrestin Binding

The G-protein coupled receptor (GPCR) rhodopsin transduces light signals in photoreceptor cells. For a rapid recovery of the receptor, efficient signal termination is mandatory. On the molecular level, this termination process starts with the phosphorylation of serines and/or threonines in the C-terminus of rhodopsin by rhodopsin kinase. Subsequently, the phosphorylated photoexcited rhodopsin is recognized by visual arrestin, which binds to the cytoplasmic loops of the receptor.In this work we focus on the real-time dynamics of helix 8, a putative cytoplasmic surface switch region in class-I GPCRs. Using multidimensional time-correlated single photon counting [1] and site-specific fluorescence labelling [2], we measured the time-resolved anisotropy changes of phosphorylated and photoactivated phosphorylated rhodopsin upon interaction with arrestin. Distinct real-time dynamics changes of helix 8 were observed after phosphosphorylation and interaction with arrestin. From real-time dynamics studies of helix 8 in rod outer segment membranes we concluded that a reduced mobility of helix 8 is a prerequisite for rhodopsin activation [2]. FTIR-Fluorescence cross-correlation measurements indicate further that changes in the environment of helix 8, as measured with a fluorescent reporter group, may correlate with a partial loss of secondary structure upon Metarhodopsin II formation [3]. The observed mobility changes after phosphorylation highlight the importance of helix 8 as a surface element, which is involved in activation, molecular recognition, and deactivation of the receptor.[1] Kim T.-Y., Winkler K., and U. Alexiev (2007). Photochemistry and Photobiology 83, 378-384[2] Alexiev, U., I. Rimke, and T. Pohlmann (2003). J. Mol. Biol. 328, 705-719[3] Lehmann N., Alexiev U., and Fahmy K. J (2007). Mol. Biol. 366, 1129-1141

Measurement biases in panel data

The objective of this paper is to examine reporting errors in panel data obtained from multi-day travel diaries. A distinction is made between within and between wave biases. The former leads to an increase in under-reporting associated with the number of days the diary is kept. The latter is related to the number of waves respondents have been participating, so-called panel experience. These biases imply that observed mobility changes between waves are partly due to reporting errors: without controlling for them, changes in mobility can not be inferred from the data. An important cause of these measurement errors is the increase in the number of days on which no trips at all were reported. In addition, shorter trips and less complex chains are more susceptible to underreporting. The methodology used in this paper provides a means of dealing with these problems. Attrition is taken into account by a rather simple measure. The paper concludes with a number of suggestions for sample and survey design.

Ionic transport in nematic liquid crystals: A study of viscous and dielectric frictions

The ionic mobilities of different species have been determined in two nematic solvents, in order to specify the relative importance of the dielectric friction and of the viscous friction in the mechanisms limiting the mobility in a liquid. The determination of the mobilities of a series of ions of different size shows the Stokes’ law can account for the observed mobility changes with the ionic radius. The study of the temperature dependence of the drift mobility in both nematic and isotropic phases shows that no discontinuity is observed at the nematic to isotropic transition, and the activation energy of mobility is found to be equal to the activation energy of viscosity. All experimental results give evidence that the dielectric friction mechanism, as described by the Fuoss–Boyd–Zwanzig model, is not the predominant factor affecting the ionic mobilities. It is concluded that the viscous friction does play the leading part in the mechanisms limiting the mobility, and that the Stokes–Einstein model can be considered as a first satisfactory approach for the description of ionic mobility in the nematic solvents.