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

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

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

Exploring the longevity advantage of doctorates in Finland and Sweden : The role of smoking- and alcohol-related causes of death

Aims: Tobacco smoking and alcohol use contribute to differences in life expectancy between individuals with primary, secondary and tertiary education. Less is known about the contribution of these risk factors to differences at higher levels of education. We estimate the contribution of smoking and alcohol use to the life-expectancy differences between the doctorates and the other tertiary-educated groups in Finland and in Sweden. Methods: We used total population data from Finland and Sweden from 2011 to 2015 to calculate period life expectancies at 40 years of age. We present the results by sex and educational attainment, the latter categorised as doctorate or licentiate degrees, or other tertiary. We also present an age and cause of death decomposition to assess the contribution of deaths related to smoking and alcohol. Results: In Finland, deaths related to smoking and alcohol constituted 48.6% of the 2.1-year difference in life expectancy between men with doctorate degrees and the other tertiary-educated men, and 22.9% of the 2.1-year difference between women, respectively. In Sweden, these causes account for 22.2% of the 1.9-year difference among men, and 55.7% of the 1.6-year difference among women, which in the latter case is mainly due to smoking. Conclusions: Individuals with doctorates tend to live longer than other tertiary-educated individuals. This difference can be partly attributed to alcohol consumption and smoking.Peer reviewe

Multiwalled carbon nanotube: Luttinger liquid or not?

We have measured IV-curves of multiwalled carbon nanotubes using end contacts. At low voltages, the tunneling conductance obeys non-Ohmic power law, which is predicted both by the Luttinger liquid and the environment-quantum-fluctuation theories. However, at higher voltages we observe a crossover to Ohm's law with a Coulomb-blockade offset, which agrees with the environment-quantum-fluctuation theory, but cannot be explained by the Luttinger-liquid theory. From the high-voltage tunneling conductance we determine the transmission line parameters of the nanotubes.Comment: RevTeX, 4 pages, 2 EPS-figures, submitted to Phys. Rev. Let

The Association Between Pregnancy Complications and Subsequent Interpregnancy Interval : a Nationwide Register-Based Quantile Logistic Regression Analysis

There is a limited number of studies examining the influence of birth complications on the length of the subsequent interpregnancy interval (IPI). This study aimed to study the association between different pregnancy complications at first pregnancy and subsequent IPI. All women with their first and second pregnancies were gathered from the National Medical Birth Register for years 2004–2018. A logistic regression model was used to assess the association between the pregnancy complication (gestational hypertension, gestational diabetes (GDM), preterm birth, perinatal mortality, shoulder dystocia) in the first pregnancy and subsequent length of the IPI. IPIs with a length in the lower quartal were considered short IPIs, and length in the upper quartal as long IPIs. Adjusted odds ratios (aOR) with 95% CIs were compared between the groups. A total of 52,709 women with short IPI, 105,604 women with normal IPI, and 52,889 women with long IPI were included. Women with gestational hypertension had higher odds for long IPI (aOR 1.12, CI 1.06–1.19), GDM had higher odds for short IPI (aOR 1.09, CI 1.09–1.13), preterm delivery had higher odds for short and long IPI (aOR 1.12, CI 1.07–1.17 for both), and perinatal mortality had higher odds for short IPI (aOR 8.05, CI 6.97–9.32) and lower odds for long IPI (aOR 1.13, CI 0.93–1.38). Women with gestational hypertension and preterm birth had higher odds for long IPI, and women with diagnosed GDM and perinatal mortality had higher odds for short IPI. We found no evidence of a difference in the length of the IPI for women with shoulder dystocia. More research on the reasons behind the subsequent long and short IPI is warranted.Peer reviewe

The association between interpregnancy interval and gestational diabetes mellitus : A nationwide register-based study in Finland

Objective: Previous results on the association between interpregnancy interval (IPI) and gestational diabetes mellitus (GDM) have been contradictory. Hence, the aim of this study was to examine the association between IPI and GDM using high-quality nationwide register data. Methods: All women with first and second pregnancies during our study period from the National Medical Birth Register during 2004–2018 were considered. A logistic regression model was used to assess the association between the length of the IPI and development of the GDM in the second pregnancy. Women were divided into three groups based on the length of the IPI: short IPI (0–11 months), normal IPI (12–47 months), and long IPI (48+ months). Adjusted odds ratios (aOR) with 95% CI were compared between the groups. Results: A total of 47 078 women were included in the study. We found no evidence of difference when women with short IPI were compared with women with normal IPI (aOR 0.99, 95% CI 0.93–1.05). Women with long IPI had increased odds for the development of GDM when compared with women with normal IPI (aOR 1.28, 95% CI 1.19–1.38). In the logistic regression model for continuous IPI, the total odds for the development of GDM increased as the IPI increased (aOR 1.05 per year, 95% CI 1.03–1.06). Conclusion: The odds for the development of GDM increased as the IPI increased. This study's results serve as a clarion call for proactive measures in GDM prevention. Moreover, they advocate for intensified investigation into the underlying factors contributing to GDM among women with extended IPI. It is imperative that these insights inform both clinical practice and further research agendas, as we strive to safeguard maternal health and well-being.Peer reviewe

Trends in mortality by labour market position around retirement ages in three European countries with different welfare regimes

&lt;p&gt;Objectives: In the face of economic downturn and increasing life expectancy, many industrial nations are adopting a policy of postponing the retirement age. However, questions still remain around the consequence of working longer into old age. We examine mortality by work status around retirement ages in countries with different welfare regimes; Finland (social democratic), Turin (Italy; conservative), and England and Wales (liberal).&lt;/p&gt; &lt;p&gt;Methods: Death rates and rate ratios (RRs) (reference rates = ‘in-work’), 1970 s–2000 s, were estimated for those aged 45–64 years using the England and Wales longitudinal study, Turin longitudinal study, and the Finnish linked register study.&lt;/p&gt; &lt;p&gt;Results: Mortality of the not-in-work was consistently higher than the in-work. Death rates for the not-in-work were lowest in Turin and highest in Finland. Rate ratios were smallest in Turin (RR men 1972–76 1.73; 2002–06 1.63; women 1.22; 1.68) and largest in Finland (RR men 1991–95 3.03; 2001–05 3.80; women 3.62; 4.11). Unlike RRs for men, RRs for women increased in every country (greatest in Finland).&lt;/p&gt; &lt;p&gt;Conclusions: These findings signal that overall, employment in later life is associated with lower mortality, regardless of welfare regime.&lt;/p&gt