In this review, self‐mixing interferometry (SMI), a new configuration of interferometry, is discussed. SMI has practical advantages compared to standard interferometry, for example SMI does not ...require any optical part external to the laser chip and can be employed in a variety of measurements. Applications range from the traditional measurements related to optical pathlength – like displacement, small‐amplitude vibrations, velocity – to sensing of weak optical echoes – for return loss and isolation factor measurements, CD readout and scroll sensing – and also, a special feature because of the interaction with the medium, measurements of physical parameters, like the laser linewidth, coherence length, and the alfa factor. Because it is also a coherent detection scheme, the SMI works close to the quantum limit of the received field, typically ‐90 dBm, so that minimum detectable amplitudes of 100 pm/ √Hz are currently achieved upon operation on diffusive targets, whereas a corner cube allows half‐wavelength counting mode – or 0.5 μm resolution – on a dynamic range up to 2 m and more. With its compact setup, the SMI is easy to deploy in the field and can interface a variety of experiments – from MEMS testing to rotating machines vibration testing to pickup of biological motility. The illustration shows a double‐channel, differential SMI incorporated in a thermomechanical test equipment to trace the mechanical hysteresis cycle of the beads of a motor‐engine brake.
In this work self‐mixing interferometry (SMI), a new configuration of interferometry, is discussed. SMI has practical advantages compared to standard interferometry, for example SMI does not require any optical part external to the laser chip and can be employed in a variety of measurements. Applications range from the traditional measurements related to optical pathlength to sensing of weak optical echoes and also measurements of physical parameters, like the laser linewidth, coherence length, and the alfa factor.
Objective
The primary aim of this article was to describe SARS‐CoV‐2 infection among pregnant women during the wild‐type and Alpha‐variant periods in Italy. The secondary aim was to compare the ...impact of the virus variants on the severity of maternal and perinatal outcomes.
Design
National population‐based prospective cohort study.
Setting
A total of 315 Italian maternity hospitals.
Sample
A cohort of 3306 women with SARS‐CoV‐2 infection confirmed within 7 days of hospital admission.
Methods
Cases were prospectively reported by trained clinicians for each participating maternity unit. Data were described by univariate and multivariate analyses.
Main outcome measures
COVID‐19 pneumonia, ventilatory support, intensive care unit (ICU) admission, mode of delivery, preterm birth, stillbirth, and maternal and neonatal mortality.
Results
We found that 64.3% of the cohort was asymptomatic, 12.8% developed COVID‐19 pneumonia and 3.3% required ventilatory support and/or ICU admission. Maternal age of 30–34 years (OR 1.43, 95% CI 1.09–1.87) and ≥35 years (OR 1.62, 95% CI 1.23–2.13), citizenship of countries with high migration pressure (OR 1.75, 95% CI 1.36–2.25), previous comorbidities (OR 1.49, 95% CI 1.13–1.98) and obesity (OR 1.72, 95% CI 1.29–2.27) were all associated with a higher occurrence of pneumonia. The preterm birth rate was 11.1%. In comparison with the pre‐pandemic period, stillbirths and maternal and neonatal deaths remained stable. The need for ventilatory support and/or ICU admission among women with pneumonia increased during the Alpha‐variant period compared with the wild‐type period (OR 3.24, 95% CI 1.99–5.28).
Conclusions
Our results are consistent with a low risk of severe COVID‐19 disease among pregnant women and with rare adverse perinatal outcomes. During the Alpha‐variant period there was a significant increase of severe COVID‐19 illness. Further research is needed to describe the impact of different SARS‐CoV‐2 viral strains on maternal and perinatal outcomes.
Tweetable
The rate of severe COVID‐19 disease increased during the Alpha‐variant period compared with the wild‐type period.
Linked article This article is commented on by J G Thornton, p. 232 in this issue. To view this mini commentary visit https://doi.org/10.1111/1471-0528.16981.
In this letter, we show that innovative physics-based simulations can be used for a comprehensive analysis of RF stages subject to random variations of technological parameters, including the ...computation of the average (deterministic) RF performance along with their statistical deviation. The variability analysis is addressed by means of the recently developed physics-based sensitivity analysis of AC parameters through Green's functions. To demonstrate the technique, we address the analysis of a FinFET mixer exploiting an innovative independent gates topology, showing that a careful design allows to maximize the mixer conversion gain, while minimizing its variability versus several physical parameters, such as the gate length, oxide thickness, and fin width.
Power amplifiers (PAs) for next generation of communication systems are expected to operate at higher frequency and bandwidth to support the growing data rates. The Doherty Power Amplifier (DPA) is ...one of the most promising circuits for the development of high efficiency PAs: its inherent structure, exploiting two interacting active devices, requires a nonlinear mixed-mode TCAD analysis with multiple devices. In this work we present for the first time a complete TCAD simulation of a DPA, exploiting an improved version of our in-house Harmonic-Balance based drift–diffusion simulator for large-signal mixed-mode analysis. We thus demonstrate that TCAD simulations are mature to assist the design of complex stages requiring multi-device large-signal analysis.
•Nonlinear TCAD simulation of multidevice circuits.•TCAD simulation of the Doherty power Amplifier.•Harmonic Balance TCAD simulations.
A new method for the measurement of the linewidth enhancement factor of semiconductor lasers is presented, based on the interferometric self-mixing effect. It is a fast and easy to perform method ...that does not require radio frequency nor optical spectrum measurements. A small fraction of the emitted light is backreflected into the laser cavity by a remote target driven by a sine waveform. The mixing of the returned and the lasing fields generates a modulation of the optical output power in the form of an interferometric waveform, with a shape that depends on the optical feedback strength and the linewidth enhancement factor /spl alpha/, according to the well-known Lang-Kobayashi theory. We show that the value of /spl alpha/ can be retrieved from a simple measurement of two characteristic time intervals of the interferometric waveform. Experimental results obtained on different laser diodes show an accuracy of /spl plusmn/6.5%.
Abstract
Since 1984 INFN and University of Pisa scientists performing experiments at Fermilab have been running a two-month summer training program for Italian students at the lab. In 1984 the ...program involved only a few physics students from the University of Pisa, but it was later extended to other INFN groups and to engineering students. Since 2004 the program has been supported in part by the US Department of Energy (DOE) in the frame of an exchange agreement with INFN and has been run by the Cultural Association of Italians at Fermilab (CAIF). In 2007 the Sant’Anna School of Advanced Studies (Pisa) established an agreement with Fermilab to share the cost of four engineering students each year. In the almost 40 years of its history, the program has hosted at Fermilab approximately 550 Italian students from more than 20 Italian universities and from some non-Italian universities. In addition, in the years 2010-2019, with the support of the Italian National Institute of Astrophyics (INAF), the Italian Space Agency (ASI), and CAIF, 30 students were hosted in other US laboratories and universities. The Fermilab training programs spanned from data analysis to design and construction of particle detectors and accelerator components, R/D on superconductive elements, theory of accelerators, and analysis of astrophysical data. At the other US laboratories the offered training was on Space Science. In 2015 the University of Pisa endorsed the program as one of its own Summer Schools. The interns are enrolled as Pisa students for the duration of the internship. They are required to write summary reports published in the Fermilab and University of Pisa web pages. Upon positive evaluation by a University board, students are acknowledged 6 ECTS credits. The entire program is expected to expand further under CAIF management. An agreement has been signed between ASI and CAIF, for ASI to support yearly three two-months fellowships in US space science. In the following we inform on student recruiting, training programs, and final evaluation
To compare guidelines from eight high-income countries on prevention and management of postpartum haemorrhage (PPH), with a particular focus on severe PPH.
Comparative study.
High-resource countries.
...Women with PPH.
Systematic comparison of guidance on PPH from eight high-income countries.
Definition of PPH, prophylactic management, measurement of blood loss, initial PPH-management, second-line uterotonics, non-pharmacological management, resuscitation/transfusion management, organisation of care, quality/methodological rigour.
Our study highlights areas where strong evidence is lacking. There is need for a universal definition of (severe) PPH. Consensus is required on how and when to quantify blood loss to identify PPH promptly. Future research may focus on timing and sequence of second-line uterotonics and non-pharmacological interventions and how these impact maternal outcome. Until more data are available, different transfusion strategies will be applied. The use of clear transfusion-protocols are nonetheless recommended to reduce delays in initiation. There is a need for a collaborative effort to develop standardised, evidence-based PPH guidelines.
Definitions of (severe) PPH varied as to the applied cut-off of blood loss and incorporation of clinical parameters. Dose and mode of administration of prophylactic uterotonics and methods of blood loss measurement were heterogeneous. Recommendations on second-line uterotonics differed as to type and dose. Obstetric management diverged particularly regarding procedures for uterine atony. Recommendations on transfusion approaches varied with different thresholds for blood transfusion and supplementation of haemostatic agents. Quality of guidelines varied considerably.
Please cite this paper as: Donati S, Senatore S, Ronconi A and the Regional maternal mortality working group. Maternal mortality in Italy: a record‐linkage study. BJOG 2011;118:872–879.
Objective To ...detect maternal deaths, analyse associated causes and compute absolute and specific maternal mortality ratio among five Italian regions in response to a recent ranking of Italy by the Lancet as having the lowest maternal mortality ratio among 181 countries.
Design Record‐linkage study.
Setting Five Italian regions.
Population All women aged 15–49 years resident in the participating regions, with one or more hospitalisations for pregnancy or any pregnancy outcome between 2000 and 2007.
Methods Maternal deaths have been identified by record linkage between the Death Registry and the Hospital Discharge Database. Different time periods were analysed according to local data availability. Cases have been selected and causes of death have been classified according to the 10th International Classification of Diseases.
Main outcome measure Maternal mortality ratio.
Results Underreporting of official figures based on death certification in the participating regions is 63%. A total of 118 maternal deaths have been identified resulting in a maternal mortality ratio of 11.8, compared with the official figure of 4.4, per 100 000 live births. Haemorrhage, thromboembolism, and hypertensive disorders of pregnancy are the leading causes of direct deaths.
Conclusions This study implies that only 37% of all maternal deaths are included in the official data. Our analysis shows a predominance of direct obstetric deaths, which implies that emphasis is needed on improvements of obstetric care.
We present a new optical instrument for vibrations measurement, based on a method to read the frequency modulation of a laser diode self-mixing interferometer. The laser source, when exposed to ...back-injection of its emitted power, is perturbed in frequency and amplitude (self-mixing effect). When the optical back-injection level is low, the self-mixing effect introduces a frequency and amplitude modulation (FM and AM) of the emitted optical field. We demonstrated with a prototype instrument that the performances of FM modulation, in terms of resolution, sensitivity and bandwidth, show an improvement of two order of magnitude with respect to well-known AM self-mixing interferometer.
Objective
Analysis of atypical cases of uterine rupture, namely, uterine rupture occurring in unscarred, preterm or prelabour uteri.
Design
Descriptive multi‐country population‐based study.
Setting
...Ten high‐income countries within the International Network of Obstetric Survey Systems.
Population
Women with unscarred, preterm or prelabour ruptured uteri.
Methods
We merged prospectively collected individual patient data in ten population‐based studies of women with complete uterine rupture. In this analysis, we focused on women with uterine rupture of unscarred, preterm or prelabour ruptured uteri.
Main Outcome Measures
Incidence, women's characteristics, presentation and maternal and perinatal outcome.
Results
We identified 357 atypical uterine ruptures in 3 064 923 women giving birth. Estimated incidence was 0.2 per 10 000 women (95% CI 0.2–0.3) in the unscarred uteri, 0.5 (95% CI 0.5–0.6) in the preterm uteri, 0.7 (95% CI 0.6–0.8) in the prelabour uteri, and 0.5 (95% CI 0.4–0.5) in the group with no previous caesarean. Atypical uterine rupture resulted in peripartum hysterectomy in 66 women (18.5%, 95% CI 14.3–23.5%), three maternal deaths (0.84%, 95% CI 0.17–2.5%) and perinatal death in 62 infants (19.7%, 95% CI 15.1–25.3%).
Conclusions
Uterine rupture in preterm, prelabour or unscarred uteri are extremely uncommon but were associated with severe maternal and perinatal outcome. We found a mix of risk factors in unscarred uteri, most preterm uterine ruptures occurred in caesarean‐scarred uteri and most prelabour uterine ruptures in ‘otherwise’ scarred uteri. This study may increase awareness among clinicians and raise suspicion of the possibility of uterine rupture under these less expected conditions.
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