Single-electron transistor made of two crossing multiwalled carbon nanotubes and its noise properties

A three-terminal nanotube device was fabricated from two multiwalled nanotubes by pushing one on top of the other using an atomic-force microscope. The lower nanotube, with gold contacts at both ends, acted as the central island of a single-electron transistor while the upper one functioned as a gate electrode. Coulomb blockade oscillations were observed on the nanotube at sub-Kelvin temperatures. The voltage noise of the nanotube single-electron transistor (SET) was gain dependent as in conventional SETs. The charge sensitivity at 10 Hz was 6×10 exp −4  e/√Hz.Peer reviewe

Unemployment and subsequent depression : A mediation analysis using the parametric G-formula

The effects of unemployment on depression are difficult to establish because of confounding and limited understanding of the mechanisms at the population level. In particular, due to longitudinal interdependencies between exposures, mediators and outcomes, intermediate confounding is an obstacle for mediation analyses. Using longitudinal Finnish register data on socio-economic characteristics and medication purchases, we extracted individuals who entered the labor market between ages 16 and 25 in the period 1996 to 2001 and followed them until the year 2007 (n = 42,172). With the parametric G-formula we estimated the population-averaged effect on first antidepressant purchase of a simulated intervention which set all unemployed person-years to employed. In the data, 74% of person-years were employed and 8% unemployed, the rest belonging to studying or other status. In the intervention scenario, employment rose to 85% and the hazard of first antidepressant purchase decreased by 7.6%. Of this reduction 61% was mediated, operating primarily through changes in income and household status, while mediation through other health conditions was negligible. These effects were negligible for women and particularly prominent among less educated men. By taking complex interdependencies into account in a framework of observed repeated measures data, we found that eradicating unemployment raises income levels, promotes family formation, and thereby reduces antidepressant consumption at the population-level.Peer reviewe

Transport in strongly disordered multiwalled carbon nanotubes

We have studied magnetic field and temperature dependence of electron transport in chemical vapor deposition synthesized highly resistive multiwalled carbon nanotubes. The analysis of the weak-localization magnetoresistance according to electron-electron interaction theories leads to very small mean free paths, l<10 nm. At lowest temperatures the sheet resistance is near RK=h/e exp 2. Both of these observations suggest that our samples are close to the strong-localization limit.Peer reviewe

Tunneling spectroscopy of disordered multiwalled carbon nanotubes

The tunneling density of states has been studied on disordered multiwalled carbon nanotubes. The tunneling conductance shows a large zero-bias anomaly, whose temperature and voltage dependence is successfully compared with the non-perturbative theory of electron tunneling into a disordered 1D electrode. The environmental Coulomb blockade is expected to set in at lower energies, where junctions can be considered to be zero-dimensional. In one of the samples, Coulomb blockade behavior is revealed over a wide range of temperatures. In this sample the tunneling is also studied using a superconducting counterelectrode, and the observed reduction of the conductivity is found to be in quantitative agreement with the theory.Peer reviewe

Multiwalled carbon nanotubes as ultrasensitive electrometers

We show that it is possible to construct low-noise single-electron transistors (SETs) using free-standing multiwalled carbon nanotubes. The 1/fα -noise of our devices, 6×10 exp −6 e/√Hz at 45 Hz, is close in the performance to the best metallic SETs of today.Peer reviewe

Multiwalled carbon nanotubes as single electron transistors

Single electron transistors (SET) are fabricated from multiwalled carbon nanotubes (MWNT) by manipulation with an atomic force microscope. The devices consist of either a single MWNT with Au contacts at the ends or of two crossing tubes. In the latter device, the lower nanotube acted as the central island of a single electron transistor while the upper one functioned as a gate electrode. Coulomb blockade oscillations were observed on the nanotube at low temperatures. The voltage noise of the nanotube-SET was gain dependent as in conventional SETs. The charge sensitivity at 10 Hz was 6x10 exp -4 e/√Hz. Furthermore, in another device where the MWNT is suspended above the substrate between the electrodes, we measure an extremely high charge sensitivity of 6x 10 exp -6 e/√Hz at 45 Hz, comparable to the best of the conventional SETs.Peer reviewe

Shot noise of a multiwalled carbon nanotube field effect transistor

We have investigated shot noise in a 6−nm-diameter, semiconducting multiwalled carbon nanotube field effect transistor at 4.2 K over the frequency range of 600–950 MHz. We find a transconductance of 3–3.5 μS for optimal positive and negative source-drain voltages V. For the gate referred input voltage noise, we obtain 0.2 and 0.3 μV/√Hz for V > 0 and V < 0, respectively. As effective charge noise, this corresponds to (2–3)×10 exp −5 e/√Hz.Peer reviewe

A Qualitative Analysis of Student Understanding of Team Function Through the use of the Jefferson Teamwork Observation Guide (JTOG)

Background: Several early IOM reports identified the need to educate medical and health professions students in delivering patient-centered care as members of interprofessional teams (IOM, 2001; IOM, 2003). Evidence shows that conducting interprofessional education during education and training prepares student learners for collaborative practice when they enter the workplace, which in turn helps to achieve the Triple Aim of 1) enhancing the patient experience; 2) improving the health of populations; and 3) decreasing costs (WHO, 2010; Berwick, et al., 2008). One way to prepare students for collaborative practice is to have them observe real teams in action. Thus, the Jefferson Teamwork Observation Guide (JTOG) was created to serve as an educational tool in aiding students to better recognize the characteristics of effective teams. It has since been used to assess teams in the majority of clinical observation, simulation and collaborative practice activities offered by Jefferson Center for Interprofessional Education (JCIPE). The JTOG is a two-part assessment comprised of identifiable characteristics of well-functioning teams drawn from the literature about teamwork. The first part consists of Likert Scale questions (strongly disagree to strongly agree) regarding the behavior of the interprofessional team observed in the domains of Values/Ethics in Interprofessional Practice, Roles/Responsibilities, Interprofessional Communication, Teams and Teamwork, and Leadership (IPEC, 2011; IPEC 2016). The second part includes qualitative questions relating to team-based care, patient-centered care, and teamwork

Association between neighbourhood characteristics and antidepressant use at older ages : a register-based study of urban areas in three European countries

Background Research evidence on the association between neighbourhood characteristics and individual mental health at older ages is inconsistent, possibly due to heterogeneity in the measurement of mental-health outcomes, neighbourhood characteristics and confounders. Register-based data enabled us to avoid these problems in this longitudinal study on the associations between socioeconomic and physical neighbourhood characteristics and individual antidepressant use in three national contexts. Methods We used register-based longitudinal data on the population aged 50+ from Turin (Italy), Stockholm (Sweden), and the nine largest cities in Finland linked to satellite-based land-cover data. This included individual-level information on sociodemographic factors and antidepressant use, and on neighbourhood socioeconomic characteristics, levels of urbanicity, green space and land-use mix (LUM). We assessed individual-level antidepressant use over 6 years in 2001-2017 using mixed-effects logistic regression. Results A higher neighbourhood proportion of low-educated individuals predicted lower odds for antidepressant use in Turin and Stockholm when individual-level sociodemographic factors were controlled for. Urbanicity predicted increased antidepressant use in Stockholm (OR=1.02; 95% CI 1.01 to 1.03) together with more LUM (OR=1.03; 1.01-1.05) and population density (OR=1.08; 1.05-1.10). The two latter characteristics also predicted increased antidepressant use in the Finnish cities (OR=1.05; 1.02-1.08 and OR=1.14; 1.02-1.28, respectively). After accounting for all studied neighbourhood and individual characteristics of the residents, the neighbourhoods still varied by odds of antidepressant use. Conclusions Overall, the associations of neighbourhood socioeconomic and physical characteristics with older people's antidepressant use were small and inconsistent. However, we found modest evidence that dense physical urban environments predicted higher antidepressant use among older people in Stockholm and the Finnish cities.Peer reviewe

EMOTIONAL ANALYSIS OF CHILDREN IN CLASS I PRIMARY SCHOOL

This study aims to describe the emotional dynamics of first grade students at the beginning of the lesson and at the end of the lesson of one elementary school in Singkawang City and to analyse the factors causing the emotions of the first grade students at the beginning of the lesson and at the end of the lesson on one elementary school in Singkawang City. This type of research is qualitative research. Sources of data used are class I and Teacher homeroom I. Data collection techniques that researchers use is participatory observation in the process of learning in the classroom at the beginning and end of the lesson. Interview techniques in the form of structured interviews used to obtain information as complete as possible. Data collection techniques with documents in the form of writing and photos. Data Collecting Instrument used in this research are observation sheet, interview questionnaire and activity photo. The results explain the emotional dynamics in the first grade students of Brother Singkawang Elementary School at the beginning of the lesson is 100% happy. At the end of the hour 18% happy, 18% sad, and 63% angry. Factors causing emotions happy at the beginning of the lesson because it can meet friends, play and learn together. As for sad and angry emotions are not visible. At the end of the lesson there are happy emotions caused by content to play, full because they have eaten and ready to learn again and can answer teacher questions. The sad emotion at the end of the lesson is caused by still want to play, sick, hot weather, tired or tired and fighting. Furthermore, feelings of anger caused by a friend's fight and bullied, hot weather, angry due to the teacher warned and hyperactive