This article introduces the Rayleigh autoregressive moving average (RARMA) model, which is useful to interpret multiple different sets of remotely sensed data, from wind measurements to multitemporal ...synthetic aperture radar (SAR) sequences. The RARMA model is indeed suitable for continuous, asymmetric, and nonnegative signals observed over time. It describes the mean of Rayleigh-distributed discrete-time signals by a dynamic structure including autoregressive (AR) and moving average (MA) terms, a set of regressors, and a link function. After presenting the conditional likelihood inference for the model parameters and the detection theory, in this article, a Monte Carlo simulation is performed to evaluate the finite signal length performance of the conditional likelihood inferences. Finally, the new model is applied first to sequences of wind speed measurements, and then to a multitemporal SAR image stack for land-use classification purposes. The results in these two test cases illustrate the usefulness of this novel dynamic model for remote sensing data interpretation.
Summary
The aim of this study was to assess the relationships between both a marker of bone formation and a marker of bone turnover and age, sex, and pubertal stage in a group (
n
= 439) of healthy ...children and adolescents. These reference data should be instrumental in interpretation of results.
Introduction
The skeletal system has high metabolic activity. In children, bone markers may be useful in diagnostics and treatment management of skeletal diseases but there could be difficulties with interpretation of results. Compared with adults, children have elevated bone marker levels due to high skeletal growth velocity and rapid bone turnover. Thus, valid age- and sex-specific reference data should be obtained for each pediatric population living in a particular climate and with a similar lifestyle. The aim of this study was to assess the relationships between both a marker of bone formation (procollagen type I N-terminal propeptide PINP) and a marker of bone turnover (osteocalcin OC) and age, sex, and pubertal stage in a group of healthy children and adolescents.
Methods
Four hundred thirty-nine healthy Caucasian children participated. Their height, weight, and pubertal stage were recorded. Fasting PINP and OC were measured using a morning blood sample.
Results
The highest levels of PINP were observed during the first year of life. There is no OC postnatal peak, but levels are higher than the adult reference interval throughout childhood. OC peaks with the pubertal growth spurt at second–third Tanner stage of breast development in girls and at second–third Tanner stage of genital development in boys. PINP peaks during second–third Tanner stage of breast development in girls and at third Tanner stage of genital development in boys.
Conclusion
This study provides reference data for OC and PINP in healthy Caucasian children from a Central European population.
A vast majority of cellular processes take root at the surface of biological membranes. By providing a two-dimensional platform with limited diffusion, membranes are, by nature, perfect devices to ...concentrate signaling and metabolic components. As such, membranes often act as "key processors" of cellular information. Biological membranes are highly dynamic and deformable and can be shaped into curved, tubular, or flat conformations, resulting in differentiated biophysical properties. At membrane contact sites, membranes from adjacent organelles come together into a unique 3D configuration, forming functionally distinct microdomains, which facilitate spatially regulated functions, such as organelle communication. Here, we describe the diversity of geometries of contact site-forming membranes in different eukaryotic organisms and explore the emerging notion that their shape, 3D architecture, and remodeling jointly define their cellular activity. The review also provides selected examples highlighting changes in membrane contact site architecture acting as rapid and local responses to cellular perturbations, and summarizes our current understanding of how those structural changes confer functional specificity to those cellular territories.
This research explores the relationship between post-traumatic stress disorder (PTSD), resulting from intense violence during the “Guardian of the Walls” operation in 2021, and economic ...decision-making. We surveyed civilians in Israel who experienced Gaza rocket attacks to understand the influence of PTSD on their financial decisions. The results revealed an interesting trend: PTSD sufferers showed a preference for immediate consumption over future savings and demonstrated a decrease in their willingness to take economic risks. These findings are significant because they offer insight into how trauma affects financial decisions, and crucial information for those helping PTSD sufferers—their relatives and therapists. It is essential for them to be aware of these tendencies to provide appropriate advice and assistance, helping the victims cope with their PTSD and make effective financial decisions in their daily lives.
Satellite images from the same scene observed over time can be composed in an image stack, which could be modeled as a 3-D cube. To handle this type of remote sensing data, on the one side, ...unidimensional dynamical models have been considered, modeling each pixel separately along the time (pixel-based approach), and exploring the temporal correlation. On the other side, 2-D approaches have been considered to process each image at one date, exploring the spatial correlation. In this article, we propose a new 3-D autoregressive (AR) (3-D-AR) model useful for multitemporal image interpretation exploring the correlation in three dimensions altogether. The 3-D-AR model is statistically defined, and a robust parameter estimation method is discussed. The tools for filtering, forecasting, and detecting anomalies are also introduced. A Monte Carlo simulation study is performed to evaluate the finite signal length performance of the robust estimation and its sensitivity to outliers. The proposed model is applied to a multitemporal normalized difference vegetation index (NDVI) image stack for filtering, prediction, and anomaly detection purposes. The numerical results show the importance of the proposed 3-D-AR model for spatiotemporal remote sensing data interpretation.
Multicellularity differs in plants and animals in that the cytoplasm, plasma membrane, and endomembrane of plants are connected between cells through plasmodesmal pores. Plasmodesmata (PDs) are ...essential for plant life and serve as conduits for the transport of proteins, small RNAs, hormones, and metabolites during developmental and defense signaling. They are also the only pathways available for viruses to spread within plant hosts. The membrane organization of PDs is unique, characterized by the close apposition of the endoplasmic reticulum and the plasma membrane and spoke-like filamentous structures linking the two membranes, which define PDs as membrane contact sites (MCSs). This specialized membrane arrangement is likely critical for PD function. Here, we review how PDs govern developmental and defensive signaling in plants, compare them with other types of MCSs, and discuss in detail the potential functional significance of the MCS nature of PDs.
Unique structural and optical properties of atomically thin two-dimensional semiconducting transition metal dichalcogenides enable in principle their efficient coupling to photonic cavities having ...the optical mode volume close to or below the diffraction limit. Recently, it has become possible to make all-dielectric nano-cavities with reduced mode volumes and negligible non-radiative losses. Here, we realise low-loss high-refractive-index dielectric gallium phosphide (GaP) nano-antennas with small mode volumes coupled to atomic mono- and bilayers of WSeFormula: see text. We observe a photoluminescence enhancement exceeding 10Formula: see text compared with WSeFormula: see text placed on planar GaP, and trace its origin to a combination of enhancement of the spontaneous emission rate, favourable modification of the photoluminescence directionality and enhanced optical excitation efficiency. A further effect of the coupling is observed in the photoluminescence polarisation dependence and in the Raman scattering signal enhancement exceeding 10Formula: see text. Our findings reveal dielectric nano-antennas as a promising platform for engineering light-matter coupling in two-dimensional semiconductors.
A highly excited atom having an electron that has moved into a level with large principal quantum number is a hydrogen-like object, termed a Rydberg atom. The giant size of Rydberg atoms leads to ...huge interaction effects. Monitoring these interactions has provided insights into atomic and molecular physics on the single-quantum level. Excitons--the fundamental optical excitations in semiconductors, consisting of an electron and a positively charged hole--are the condensed-matter analogues of hydrogen. Highly excited excitons with extensions similar to those of Rydberg atoms are of interest because they can be placed and moved in a crystal with high precision using microscopic energy potential landscapes. The interaction of such Rydberg excitons may allow the formation of ordered exciton phases or the sensing of elementary excitations in their surroundings on a quantum level. Here we demonstrate the existence of Rydberg excitons in the copper oxide Cu2O, with principal quantum numbers as large as n = 25. These states have giant wavefunction extensions (that is, the average distance between the electron and the hole) of more than two micrometres, compared to about a nanometre for the ground state. The strong dipole-dipole interaction between such excitons is indicated by a blockade effect in which the presence of one exciton prevents the excitation of another in its vicinity.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Polymers showing an upper critical solution temperature (UCST) in water are rare. Recently, the nonionic homopolymer poly(N-acryloyl glycinamide) (poly(NAGA)) has been shown to exhibit a sharp upper ...critical solution temperature in pure water as well as in electrolyte solution. Although poly(NAGA) is known for decades the UCST behavior had not been reported. The first controlled radical polymerization of poly(NAGA) by the RAFT (reversible addition–fragmentation transfer) process was also achieved recently, but no UCST was observed. The present study shows that traces of ionic groups in the polymer prevent phase separation. Failure to notice the UCST in the past was because ionic groups have been introduced unintentionally by either acrylate impurities in the monomer, hydrolysis of the polymer side chains, and/or usage of ionic initiators or chain transfer agents. A synthetic procedure for high purity NAGA monomer free of ionic impurities is reported. It is also shown how to obtain stable aqueous solutions of nonionic poly(NAGA) so that the UCST behavior can be exploited in pure water as well as in a physiological milieu. Further, ultrasensitive differential scanning calorimetry and light scattering were used to get insights into the phase separation mechanism. We believe that this knowledge is transferable to other systems and will greatly accelerate research in the field of macromolecules that feature thermally reversible hydrogen bonding.
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