37 research outputs found
Ferro-Orbitally Ordered Stripes in Systems with Alternating Orbital Order
We establish a novel mechanism of stripe formation in doped systems with
alternating orbital order --- the stripe takes the form of a
ferro-orbitally ordered domain wall separating domains with staggered order and
allowing for deconfined motion of holes along the stripe. At a finite level of
hole concentration this gives rise to the stability of this solitonic type of
stripes, while we show that the phase change of the staggered order by
plays a minor role in orbitally ordered systems. These results shed new light
on the physics of doped materials in which orbital degeneracy is present.Comment: 5 pages, 4 figure
Ultrafast optical properties of stoichiometric and non-stoichiometric refractory metal nitrides TiNx, ZrNx, and HfNx
Refractory metal nitrides have recently gained attention in various fields of
modern photonics due to their cheap and robust production technology,
silicon-technology compatibility, high thermal and mechanical resistance, and
competitive optical characteristics in comparison to typical plasmonic
materials like gold and silver. In this work, we demonstrate that by varying
the stoichiometry of sputtered nitride films, both static and ultrafast optical
responses of refractory metal nitrides can efficiently be controlled. We
further prove that the spectral changes in ultrafast transient response are
directly related to the position of the epsilon-near-zero region. At the same
time, the analysis of the temporal dynamics allows us to identify three time
components - the "fast" femtosecond one, the "moderate" picosecond one, and the
"slow" at the nanosecond time scale. We also find out that the
non-stoichiometry does not significantly decrease the recovery time of the
reflectance value. Our results show the strong electron-phonon coupling and
reveal the importance of both the electron and lattice temperature-induced
changes in the permittivity near the ENZ region and the thermal origin of the
long tail in the transient optical response of refractory nitrides
The clinical usefulness of biochemical (free β-hCG, PAPP-A) and ultrasound (nuchal translucency) parameters in prenatal screening of trisomy 21 in the first trimester of pregnancy
Objectives: The aim of the study was to analyze the correlation of multiples of the normal median of PAPP-A, free β-hCG levels and nuchal translucency values in prenatal, first trimester screening of trisomy 21 in pregnant women. Material and methods: 251 pregnant women underwent antenatal screening at 11–13+6 weeks of pregnancy which was composed of the measurement of free β-human chorionic gonadotropin (β-hCG) and pregnancy-associated plasma protein (PAPP-A) levels in the maternal serum and an ultrasound assessment of nuchal translucency (NT). The pregnant women with a high risk of trisomy 21 (≥ 1:300) were given amniocentesis to verify fetal defects. There were 217 cases of normal fetal karyotype and 34 cases of trisomy 21. PAPP-A, β-hCGMoM and NT values were analyzed for the predefined ranges. Results: 85% cases of trisomy 21 had elevated free β-hCGMoM ( > 1.5) and only 53% of these had a PAPP-AMoM result below 0.5 (p < 0.05). Analysis of NT in selected ranges of β-hCG ( > 1.5) and PAPP-AMoM ( < 0.05), which are typical for Down Syndrome values, showed that not all fetuses with Down Syndrome presented with an increased NT. Respectively 44.15% and 26.5% of fetuses presented with increased NT. Characteristic for trisomy 21, a correlation with all 1st trimester screening tests’ parameters occurred in only 23.5% of cases. In 53% of cases the results were atypical. Conclusions: The PAPP-A and β-hCG values in the selected MoM ranges did not shown a correlation to the NT measurement, therefore they are independent factors in the diagnosis of trisomy 21. Simultaneous biochemical and ultrasound testing is an indispensable condition for prenatal diagnosis of trisomy 21 in the 1st trimester of pregnancy.
Maternal factors, ultrasound and placental function parameters in early pregnancy as predictors of birth weight in low-risk populations and among patients with pre-gestational diabetes
Objectives: The aim of our work was to assess the usefulness of maternal factors, ultrasound and placental function parameters during early pregnancy as predictors of birth weight in populations of healthy pregnant women and women suffering from pregestational diabetes.
Material and methods: A study group comprised 97 healthy women and 160 women with pregestational diabetes (PGDM, type 1), all in singleton pregnancy. Ultrasound examination was performed between weeks 11 and 14, and in weeks 20 and 30 of gestation, based on recommendations of the Polish Society of Gynecologists and Obstetricians, Ultrasonography Division. We also checked uterine artery blood flow parameters. During the first trimester consultation, all patients were surveyed and the following data were collected: age, BMI, reproductive history, comorbidities and smoking. We also collected blood samples and assessed PlGF, PAPP-A, and BhCG levels.
Results: Our study showed that newborn birth weight negatively correlated with mother’s age, her diastolic blood pressure, PI of her uterine arteries and BhCG protein levels. Moreover, birth weight directly correlated with PlGF and PAPPA-A protein levels, and maternal early-pregnancy BMI.
Conclusions: LGA diagnosis in the first trimester of pregnancy allows for selection and modification of some risk factors and closer monitoring of endangered fetuses throughout the pregnancy, with emphasis on the perinatal period. Parameters with confirmed usefulness in the prediction of birth weight in the first trimester included: maternal age, BMI, blood pressure, PAPP-A, BhCG and PlGF levels, fetal CRL and uterine artery PI
Mid-trimester ultrasound parameters for predicting birth weight in low risk pregnancies vs high-risk pregnancies complicated with pre-gestational diabetes mellitus
Objectives: The aim of the study was to assess the utility of mid-trimester ultrasound parameters in predicting birth weight in low-risk pregnancy and high-risk pregnancy complicated with pregestational diabetes mellitus. Material and methods: A study group comprised 97 healthy women and 160 women with pregestational diabetes (PGDM, type 1), all in singleton pregnancy. Ultrasound examination was performed between weeks 11 and 14, and in weeks 20 and 30 of gestation, based on recommendations of the Polish Society of Gynecologists and Obstetricians, Ultrasonography Division. We also checked uterine artery blood flow parameters. Results: There is a correlation between the birth weight and ultrasound-ascertained parameters, including those characterising uterine artery blood flow and foetal biometry [abdominal circumference (AC), femoral length (FL), biparietal dimension (BPD)].The biparietal dimension (BPD), head circumference (HC) abdominal circumference (AC) and pre-existing diabetes are the ultrasound predictors of LGA. The presence of an early-diastolic uterine artery blood flow waveform notching, as well as the uterine artery pulsatility index (UAPI), femoral length (FL) and hypertension in pregnancy are the ultrasound predictors of SGA. In the subset of women with pre-gestational diabetes (PGDM), there is a negative correlation between the birth weight and the uterine artery pulsatility index and early-diastolic uterine artery blood flow waveform notching. In women with pre-gestational diabetes mellitus (PGDM), femoral length (FL) is a significant predictor of LGA and in case of SGA significant predictors are uterine artery pulsatility index, artery blood flow waveform notching and femoral length (FL). Conclusions: Midtrimester ultrasound parameters with confirmed usefulness in the prediction of birth weight in low-risk pregnancy and high-risk pregnancy complicated with pregestational diabetes mellitus include: uterine artery PI, early-diastolic uterine artery blood flow waveform notching and foetal biometry
26th Annual Computational Neuroscience Meeting (CNS*2017): Part 3 - Meeting Abstracts - Antwerp, Belgium. 15–20 July 2017
This work was produced as part of the activities of FAPESP Research,\ud
Disseminations and Innovation Center for Neuromathematics (grant\ud
2013/07699-0, S. Paulo Research Foundation). NLK is supported by a\ud
FAPESP postdoctoral fellowship (grant 2016/03855-5). ACR is partially\ud
supported by a CNPq fellowship (grant 306251/2014-0)
An accurate fingerprint reference point determination method based on curvature estimation of separated ridges
This paper presents an effective method for the detection of a fingerprint’s reference point by analyzing fingerprint ridges’ curvatures. The proposed approach is a multi-stage system. The first step extracts the fingerprint ridges from an image and transforms them into chains of discrete points. In the second step, the obtained chains of points are processed by a dedicated algorithm to detect corners and other points of highest curvature on their planar surface. In a series of experiments we demonstrate that the proposed method based on this algorithm allows effective determination of fingerprint reference points. Furthermore, the proposed method is relatively simple and achieves better results when compared with the approaches known from the literature. The reference point detection experiments were conducted using publicly available fingerprint databases FVC2000, FVC2002, FVC2004 and NIS