Repeat Period Research Articles

Sex-dependent effects of ethanol withdrawal from a single- and repeated binge episode exposures on social anxiety-like behavior and neuropeptide gene expression in adolescent rats

Ethanol withdrawal sensitivity is a risk factor for the development of alcohol use disorder. Heavy episodic drinking during adolescence often encompasses repeated periods of withdrawal. Adolescent intermittent ethanol exposure of laboratory rodents produces several neurobiological deficits that differ between sexes, but the sensitivity to withdrawal as a contributor to the observed sex differences is not clear. The current study assessed the impact of acute withdrawal from a single- and repeated binge ethanol episodes during adolescence as well as protracted abstinence from repeated binge episodes on social anxiety-like behavior (indexed via significant decreases of social investigation) as well as oxytocin (OXT) and vasopressin (AVP) system gene expression in the hypothalamus (HYP) and central amygdala (CeA) in male and female Sprague Dawley rats. Females displayed social anxiety-like behavior during withdrawal from a single binge episode, whereas both sexes showed social anxiety-like changes following acute withdrawal from repeated binge episodes. After a period of protracted abstinence, only males still displayed ethanol-associated social alterations. Analysis of gene expression in separate, non-socially tested subjects revealed that withdrawal from repeated binge episodes during adolescence increased AVP gene expression in the HYP of males and decreased it in females. Males also displayed increased AVP and OXTR gene expression during acute withdrawal from repeated binge episodes in the CeA, with these changes persisting into adulthood. Together, these findings suggest that adolescent females are sensitive to withdrawal from both acute and repeated ethanol exposures, whereas males are sensitive to withdrawal from repeated ethanol exposures, with affective and transcriptional changes persisting into adulthood.

‘Not taking medications and taking medication, it was the same thing:’ perspectives of antiretroviral therapy among people hospitalised with advanced HIV disease

BackgroundDespite HIV's evolution to a chronic disease, the burden of advanced HIV disease (AHD, defined as a CD4 count of < 200 cells/uL or WHO clinical Stage 3 or 4 disease), remains high among People Living with HIV (PLHIV) who have previously been prescribed antiretroviral therapy (ART). As little is known about the experiences of patients hospitalised with AHD, this study sought to discern social forces driving hospitalisation with AHD. Understanding such forces could inform strategies to reduce HIV-related morbidity and mortality.MethodsWe conducted a qualitative study with patients hospitalised with AHD who had a history of poor adherence. Semi-structured interviews were conducted between October 1 and November 30, 2023. The Patient Health Engagement and socio-ecological theoretical models were used to guide a thematic analysis of interview transcripts.ResultsTwenty individuals participated in the research. Most reported repeated periods of disengagement with HIV services. The major themes identified as driving disengagement included: 1) feeling physically well; 2) life circumstances and relationships; and 3) health system factors, such as clinic staff attitudes and a perceived lack of flexible care. Re-engagement with care was often driven by new physical symptoms but was mediated through life circumstances/relationships and aspects of the health care system.ConclusionsCurrent practices fail to address the challenges to lifelong engagement in HIV care. A bold strategy for holistic care which involves people living with advanced HIV as active members of the health care team (i.e. ‘PLHIV as Partners’), could contribute to ensuring health care services are compatible with their lives, reducing periods of disengagement from care.

Multipath mitigation for GPS/Galileo/BDS-3 precise point positioning with overlap-frequency signals

The multipath effect is a major Global Navigation Satellite System (GNSS) error source due to its environment-dependent characteristic, which complicates its mitigation process for the high-rate determination of displacements. For instance, Sidereal Filtering (SF) and Multipath Hemispherical Map (MHM) require the observations spanning at least one full cycle of satellite orbit repeat period (e.g., ten days for Galileo navigation satellite system (Galileo) to reproduce the satellite geometry against ground stations. As a consequence, the practicability of SF and MHM is limited due to potential station-surrounding changes over a long period. In this study, we used the overlap-frequency signals on Global Positioning System (GPS) L1/L5, Galileo E1/E5a, and BeiDou-3 Navigation Satellite System (BDS-3) B1C/B2a to construct an interoperable MHM (i.e., MHM_GEC) across constellations to mitigate multipath more efficiently. We thus used 31 days of 1-Hz GPS/Galileo/BDS-3 data at 21 stations in Europe to compare this overlap-frequency MHM with those GNSS-specific MHMs (i.e., MHM_G for GPS, MHM_E for Galileo, and MHM_C for BDS-3), as well as SF. It is confirmed that the multipath effects on overlap-frequency signals are of a high spatial consistency across all GNSS. The mean reduction rate of applying MHM_GEC to GPS, Galileo, and BDS-3 carrier-phase residuals is 25%, 31%, and 28.5%, respectively, which are up to 25 percentage points higher than those of MHM_G, MHM_E, and MHM _C. Furthermore, the MHM_GEC constructed using 5 to 6 days of data can improve the positioning precision by 40%, outperforming the MHM_E, MHM_C, and SF using 10 days of data. Therefore, the interoperable MHM_GEC is more efficient in mitigating multipath effects for high-precision GNSS positioning.

HAEMATOLOGICAL PROFILE OF LAYING HENS AFTER NEWCASTLE DISEASE VACCINATION

Newcastle disease (ND) is a viral disease that can cause high mortality in chickens. Hundreds of chickens died due to ND disease. Morbidity and mortality due to ND disease is very large. Viral diseases cannot be treated with antibiotics. Therefore prevention can only be done by vaccination. However, vaccination failure often occurs, it has been proven that there are still many reports of ND cases. Thus, to find out early before sick chickens are attacked by ND, this research aims to determine the hematological profile including: RBC, Hb, HCT, MCH, MCHC, MCH, PLT, WBC, Eosinophils, Monocytes, Neutrophils and Lymphocytes. The research method was a field survey with purposive sampling with blood sampling as a repeat period. The research sample consisted of 40 laying hens, 30 of which were vaccinated with the active ND vaccine of the Lasota strain and 10 without vaccination. Blood samples were taken with anticoagulation four times, namely once pre-vaccination and three times post-vaccination. The data obtained were analyzed by means of variance followed by the Duncan test using SPSS version 25. The results of the study stated that RBC, Hb, HCT, MCV, Neutrophils and Lymphocytes were significantly different (P&lt;0.05). Meanwhile MCV, MCHC, PLT, WBC, Eosinophils and Monocytes were not significantly different (P&gt;0.05).

Penerapan Terapi Murottal dan Bermain Terapeutik dalam Asuhan keperawatan pada Pasien Anak Leukemia Limfoblastik akut (ALL) dengan Ansietas di Ruangan Kronis Irna Anak RSUP Dr. M. Djamil Padang

Leukemia is the most common type of cancer in children. Long and repeated treatment periods cause children to experience hospitalization which has a psychological impact. One of the psychological impacts that children most often experience is anxiety. Anxiety needs to be anticipated, controlled and overcome so that the patient's quality of life remains optimal. One way is murottal therapy and therapeutic coloring play. Dr. Dr. Hospital's medical record data. M. Djamil Padang, recorded 169 cases of leukemia in 2022. The research aims to apply murottal therapy and therapeutic play (coloring) in the care of pediatric patients with Acute Lymphoblastic Leukemia (ALL) with anxiety in the chronic room of IRNA Children's Hospital Dr. M. Djamil Padang. Descriptive research design with a case study approach in the pediatric IRNA chronic room from 15 May - 3 June 2023. The research population was all 8 pediatric patients with ALL. The sample was 2 participants with ALL who met the criteria. The results of the research on the second participant showed a difference in anxiety levels before and after murottal therapy and therapeutic play (coloring) from anxiety level 5 (very anxious) to 2 (happy). Advice to nurses in the children's room to carry out Murottal therapy and therapeutic play for leukemia children who experience anxiety due to hospitalization.

Spatially Amplified and Rigid Junction in Diblock Copolymers: Reduced Microphase Separation Size via Interface Expansion.

We introduce an approach in diblock copolymer design, where modifying the junction point with rigid bulky monomer expands the cross-sectional area of the interface and leads to a decrease in the repeat period. Using living anionic polymerization, we synthesized a series of dialkynyl midfunctionalized poly(styrene-b-methyl methacrylate) (PSM-DA) and functionalized them using the thiol-alkyne click reaction with specifically selected rigid bulky monomers: PSS-(3-mercapto)propyl-heptaisobutyl substituted (PSS) and 1-adamantanethiol (ADA). This modification, though involving only a single monomer unit within the diblock copolymer structure, brought about a significant reduction in domain size, with PSS and ADA reducing it by 18% and 15%, respectively. The results indicate a method for reducing the domain sizes of block copolymers, which could lead to advancements in lithography and various nanotechnological applications.

ConvGRU-MHM: a CNN GRU-enhanced MHM for mitigating GNSS multipath

In high-precision global navigation satellite system (GNSS) short-baseline positioning, multipath is the main source of errors. If the station environment is quasi-static, repeat periods of satellites can be utilized to generate time- or space-dependent multipath models to mitigate multipaths. However, two general problems are associated with the multipath models constructed based on satellite mechanics: (1) an accuracy decrease occurs when the above models are applied to multipath mitigation over a long time-span; (2) when constructing the spatial and temporal grids of the satellite-based spatially dependent multipath model, it is challenging to balance computational efficiency and spatial resolution. We propose a convolutional neural network-gated recurrent unit enhanced multipath hemispherical map (ConvGRU-MHM) in the observational domain to address these problems. The proposed method directly mines the deep features of elevation, azimuth angle, and multipath and the mapping relationship between these to establish a real-time prediction model. The predicted multipath is obtained and returned to the observation equation for multipath mitigation when the real-time position of the satellite is placed in the pre-trained model. We compared the multipath mitigation performance of sidereal filtering and a MHM with that of the ConvGRU-MHM to demonstrate the advantages of the proposed method. The experimental results are as follows: (1) in the short time-span (first 20 d), the mean accuracy improvements of the ConvGRU-MHM in the E/N/U direction performed better than those of the SF and MHM; and (2) in the long-term time (after 50 d), the mean accuracy improvements of the ConvGRU-MHM in the E/N/U direction are higher than that of the SF and MHM by 10%–20%. As a lightweight model, the ConvGRU-MHM can effectively improve the measurement accuracy of GNSS real-time monitoring in fields, such as deformation monitoring and seismic research.

Beyond Exact Repeat Missions: Embracing Geodetic Altimetry for Inland Water Monitoring and Modeling

Satellite radar altimetry has become an essential tool for hydrological research over the past 2 decades. Unlike imagery that quantifies the water dynamics from the horizontal dimension, altimetry observations deliver vertical information, which is crucial for hydrological research. Geodetic mission (GM) altimetry data, characterized by long repeat periods compared to exact repeat missions, have been underutilized in hydrology. This paper aims to advocate for integrating geodetic altimetry data into inland water research and bring awareness to its potential applications. We demonstrated the values of GM data from CryoSat-2, Saral/AltiKa, Jason-1, and Jason-2 through 3 applications: (a) large-scale lake monitoring for improved understanding of regional and global hydrological cycles, (b) retrieval of local geoid undulations over large lakes to enhance the precision of individual water level observations, and (c) mapping river longitudinal profiles and construction of time series of river levels. We believe that the findings of this study will pave the way for more comprehensive utilization of geodetic altimetry data in diverse hydrological applications, ultimately advancing inland water altimetry.

Baseline and recurrent exposure to the standard dose of artemisinin-based combination therapies (ACTs) induces oxidative stress and liver damage in mice (BALB/c)

BackgroundIn malaria-endemic countries, repeated intake of artemisinin-based combination therapies (ACTs) is rampant and driven by drug resistance, improper usage, and easy accessibility. Stress effects and potential liver toxicity due to the frequent therapeutic use of ACTs have not been extensively studied. Here, we investigated the effects of repeated treatment with standard doses of the commonly used ACTs artemether/lumefantrine (A/L) and artesunate-amodiaquine (A/A) on oxidative stress and liver function markers in male mice (BALB/c).MethodsForty Five mice were divided into three groups: control, A/L, and A/A. The drugs were administered three days in a row per week, and the regimen was repeated every two weeks for a total of six cycles. The levels of oxidative stress and liver function markers were measured in both plasma and liver tissue after initial (baseline) and repeated exposures for the second, third, and sixth cycles.ResultsExposure to A/L or A/A caused a significant (p < 0.001) increase in plasma malondialdehyde (MDA) levels after the first and repeated exposure periods. However, Hepatic MDA levels increased significantly (p < 0.01) only after the sixth exposure to A/A. Following either single or repeated exposure to A/L or A/A, plasma and liver glutathione peroxidase (GPx) and catalase (CAT) activities, plasma aspartate and alanine transaminase, alkaline phosphatase activity, and bilirubin levels increased, whereas total plasma protein levels decreased significantly (p < 0.001). Varying degrees of hepatocyte degeneration and blood vessel congestion were observed in liver tissues after a single or repeated treatment period.ConclusionIrrespective of single or repeated exposure to therapeutic doses of A/L or A/A, plasma oxidative stress and liver damage were observed. However, long-term repeated A/A exposure can led to hepatic stress. Compensatory processes involving GPx and CAT activities may help reduce the observed stress.

Averaging equation of three-dimensional tracer transport by a dual approach

The conventional method for calculating averaged tracer concentration in three-dimensional tracer transport equation relies on classical averaging, which averages tracer concentration data obtained from the tracer transport equation in turbulent flow. However, the averaging tracer concentration quantity calculated by this method is not precisely the same as the one obtained by the dual approach. To address this issue, the author proposes a more intricate dual approach for averaging the three-dimensional tracer transport equation in turbulent flow. This paper describes how the author performs two integrations: one from time t to t + r (where r < T, T being the repeated period of fluctuating concentration), and another from time t to time t + T. The fluctuating concentration quantity in turbulent flow is modeled using the trigonometric Fourier series. The resulting three-dimensional mathematical model of tracer transport obtained by this dual approach is more comprehensive than the one obtained by the classical method.

FREQUENCY ANALYSIS OF DELI RIVER FLOOD DISTRIBUTION PLAN USING THE GUMBEL PROBABILITY DISTRIBUTION METHOD

The Deli river basin is one of the rivers in North Sumatra Province which is in Medan City with an area of ​​394.88 km2 and a length of 166.01 km. Medan Maimun District which has an area of ​​2.98 km2 and a population density of 16,520 people/km2. Medan Mimun sub-district is one of the flood-prone areas which is drained by the Deli River. The cause of the flooding that occurred in Medan Maimun District was high rainfall so that the river flow rate increased and drainage was poor. So that the problem of flooding in the Deli river watershed, Medan Maimun sub-district, can hamper community activities, these floods can also harm and endanger the community. The flood discharge plan for each repeat period where the variable used is the maximum daily rainfall for 10 years From 2013-2022 which is sourced from the BMKG Deli Serdang. In this study using frequency analysis and then proceed with the Gumbel Probability Distribution method, Normal Distribution Log Person Type III. The result of this study with hydrological data and distribution test, the suitable method for analyzing the planned flood discharge in the Deli River is Log Person Type III that it can be flood discharge for a 2 year retention period is 12.7684672 m3/sec, 5 year return period is 12.56275855 m3/sec, 10 year return period is 15.91400029 m3/sec, 25 year return period is 16.87871678 m3/sec, 50 year return period is 17.43836748 m3/sec and a 100 year return period is 17.89619614 m3/sec.&#x0D; &#x0D; Keywords: Rainfall, Deli River, Planned Flood Discharge&#x0D;

Nonlinear quantum dot light emitting diode dynamics and synchronization with optoelectronic feedback

We studies a three-variable dimensionless model for a quantum dot light emitting diode (QD-LED) subject to optoelectronic feedback (OEFB). In dependence of the feedback strength and delay-time we analyze complex bifurcation scenarios for the intensity of the emitted light as well as time series, fast Fourier translate (FFT) and phase plane of all dynamic variables in order to elucidate the dynamics of the light emitting diode. The chaotic dynamic is completely determined by both the variation of the OEFB strength and delay-time of the QD-LED, as evidenced by bifurcation diagram. Our results show that small delay time lead to repeat periodicity of the light emitting towards OEFB. Furthermore, we study chaos synchronization of two QD-LED which are coupled via a unidirectional and bidirectional coupling system. When periodic systems are non-identical, both unidirectional and bidirectional systems depending on the coupling strength parameter the system exhibits completely synchronization. Residual chaos, the mean coherence and entropy are discussed as well.

Averaging Navier–Stokes Equations by a Dual Approach

The current three-dimensional averaging mathematical model of flow, also known as the Reynolds averaged Navier–Stokes equations or Reynolds equations, was developed based on the idea of Reynolds in 1895. This model is given by the classical averaging of velocity and pressure parameters from the three-dimensional Navier–Stokes equations. However, by doing this, these averaging parameters obtained by this classical approach are not generalized in comparison to ones estimated by the dual approach. This paper proposes a dual approach to establishing the three-dimensional flow equation. The model setup is more complicated than the classical model in terms of integration because the procedure can be repeated several times. In this paper, the authors perform twice: (1) first, integration of the velocity and pressure parameters from time [Formula: see text] to [Formula: see text], with time [Formula: see text], where [Formula: see text] is the repeated period of parameters; (2) second, integration from time t to [Formula: see text]. Fluctuating quantities such as velocity and pressure in turbulent flow, over time, are simulated using trigonometric Fourier series. The three-dimensional flow model obtained from this dual approach could provide more accurate results than those given by the Reynolds averaged Navier–Stokes equations.

Calorimetric, volumetric and structural studies of the interaction between chlorogenic acid and dipalmitoylphosphatidylcholine bilayers

Chlorogenic acid (CGA) is the main component of coffee and an antioxidant. CGA has been reported to bear various good health effects. At the same time, it has been found that the addition of CGA induces an undesirable deformation of red blood cells. This fact suggests that CGA may bind to the proteins or/and membrane lipids of red blood cells. This study aimed to examine how CGA binds the bilayers of phosphatidylcholine (PC), one of red blood cells' primary lipids. To this end, we investigated the effect of CGA on the phase behavior and the structure of dipalmitoyl-PC (DPPC) bilayers in the form of multi-lamellar vesicles. Calorimetry and dilatometry measurements showed that the DPPC chain melting transition cooperativity decreases as increasing CGA concentrations. In addition, X-ray diffraction results showed that the lamellar repeat periodicity becomes disordered, and the periodicity disappears completely at high CGA concentrations. Together with these findings, it can be inferred that the CGA molecules do not penetrate inside the DPPC bilayers but bind to their surface in a negatively charged form.

Theory and Experiment Analysis on the Influence of Floods on a GNSS Pseudo-Range Multipath and CNR Signal Based on Two Cases Study in China

The surrounding environment of a GNSS observation station is changed during a flood, and this results in a more serious multipath than in a normal environment. Considering that the multipath error is largely related to the pseudo-range multipath and CNR (Carrier-to-noise ratio) of the GNSS signal, the influence of floods on a pseudo-range multipath and CNR is analyzed in theory and through experiment. To ensure the accuracy of the analysis results, the ground track repeat period of GPS, GLONASS, and BDS satellites is investigated from the perspective of theory and skyplots. Two real cases study collected in Zhengzhou and Xinxiang, China, in 2021, are used to demonstrate the influence of floods on a pseudo-range multipath and CNR in detail. Experimental results show that the pseudo-range multipath of a GPS satellite performs more seriously during a flood. The maximum RMS increase rate is approximately 17.85%, and the average of all other satellites with a whole arc is approximately 6.55%. In addition, the CNR of three GNSS systems performs a decrease during a flood. For GPS and GLONASS satellites, the decrease performs more seriously at a high elevation angle than that at a low elevation angle. The maximum decrease is approximately 5 dB-Hz for the GPS satellite and approximately 7 dB-Hz for the GLONASS satellite. In terms of the BDS system, the CNR of all three orbital type satellites decreases during a flood. The average decrease is approximately 2 dB-Hz for BDS MEO and GEO satellites, and about 1 dB-Hz for the BDS IGSO satellite.

Mapping 2‐D Bedload Rates Throughout a Sand‐Bed River Reach From High‐Resolution Acoustical Surveys of Migrating Bedforms

AbstractThis paper introduces a method for determining spatially‐distributed, 2‐D bedload rates using repeat, high‐resolution surveys of the bed topography. As opposed to existing methods, bedform parameters and bedload rates are computed from bed elevation profiles interpolated along the local bedform velocities. The bedform velocity fields are computed applying Large‐Scale Particle Image Velocimetry, initially developed for surface velocity measurements, to pairs of successive Digital Elevation Models (DEMs). The bathymetry data are interpolated along the direction of each bedform velocity and the mean height of the closest bedform is computed. The dune shape factor is also evaluated along each bedform direction of travel. The local bedload fluxes can be computed by multiplying the bedform velocity by its mean height averaged over the successive two DEMs, and they can be time‐averaged over a series of DEM pairs. This method is applied to a high‐resolution acoustical survey of an approximately 300 m long by 40 m wide reach of the Colorado River in Grand Canyon upstream from Diamond Creek, USA. The repeat period was about 6–10 min and bed elevation was interpolated every 0.25 m. The obtained results provide insight to the spatial and temporal variability of bedload rates, bedform parameters and bedload fluxes through cross‐sections. The method can be applied to other repeated acoustical surveys of river reaches provided that the space and time resolutions are high enough to capture the local movement of bedforms.

Landsat 9 Cross Calibration Under-Fly of Landsat 8: Planning, and Execution

During the early post-launch phase of the Landsat 9 mission, the Landsat 8 and 9 mission teams conducted a successful under-fly of Landsat 8 by Landsat 9, allowing for the near-simultaneous data collection of common Earth targets by the on-board sensors for cross-calibration. This effort, coordinated by the Landsat Calibration and Validation team, required contributions from various entities across National Aeronautics and Space Administration and U.S. Geological Survey such as Flight Dynamics, Systems, Mission Planning, and Flight Operations teams, beginning about 18 months prior to launch. Plans existed to allow this under-fly for any possible launch date of Landsat 9. This included 16 ascent plans and 16 data acquisition plans, one for every day of the Landsat orbital repeat period, with a minimum of 5 days of useful coverage overlap between the sensors. After the Landsat 9 launch, the plan executed, and led to the acquisition of over 2000 partial to full overlapping scene pairs. Although containing less than the expected number of scenes, this dataset was larger than previous Landsat mission under-fly efforts and more than sufficient for performing cross-calibration of the Landsat 8 and Landsat 9 sensors. The details of the planning process and execution of this under-fly are presented.

Automatic delineation of cracks with Sentinel-1 interferometry for monitoring ice shelf damage and calving

Abstract. Monitoring the evolution of ice shelf damage such as crevasses and rifts is important for a better understanding of the mechanisms controlling the breakup of ice shelves and for improving predictions about iceberg calving and ice shelf disintegration. Nowadays, the previously existing observational gap has been reduced by the Copernicus Sentinel-1 synthetic aperture radar (SAR) mission that provides a continuous coverage of the Antarctic margins with a 6 or 12 d repeat period. The unprecedented coverage and temporal sampling enables, for the first time, a year-round systematic monitoring of ice shelf fracturing and iceberg calving, as well as the detection of precursor signs of calving events. In this paper, a novel method based on SAR interferometry is presented for an automatic detection and delineation of active cracks on ice shelves. Propagating cracks cause phase discontinuities that are extracted automatically by applying a Canny edge detection procedure to the spatial phase gradient derived from a SAR interferogram. The potential of the proposed method is demonstrated in the case of Brunt Ice Shelf, Antarctica, using a stack of 6 d repeat-pass Sentinel-1 interferograms acquired between September 2020 and March 2021. The full life cycle of the North Rift is monitored, including the rift detection, its propagation at rates varying between 0.25 and 1.30 km d−1, and the final calving event that gave birth to the iceberg A74 on 26 February 2021. The automatically delineated cracks agree well with the North Rift location in Landsat 8 images and with the eventual location of the ice shelf edge after the iceberg broke off. The strain variations observed in the interferograms are attributed to a rigid-body rotation of the ice about the expanding tip of the North Rift in response to the rifting activity. The extent of the North Rift is captured by SAR interferometry well before it becomes visible in SAR backscatter images and a few days before it could be identified in optical images, hence highlighting the high sensitivity of SAR interferometry to small variations in the ice shelf strain pattern and its potential for detecting early signs of natural calving events, ice shelf fracturing and damage development.

In Situ Grazing-Incidence SAXS Investigation of Thermal-Induced Self-Assembly Process of PS-b-PMMA Films Deposited on Surface-Modified Substrate.

Directed self-assembly of block copolymers (BCPs) is widely investigated for its potential application in surface patterning. The self-assembly kinetics of BCP based on modified layers is the key to realizing structural control for obtaining highly ordered lamellar grains. In this study, morphological evolution of PS-b-PMMA films during the thermal-induced self-assembly process was investigated via the in situ grazing-incidence small-angle X-ray scattering (GISAXS) technique. In the first heating stage, reorientation of lamellar grains occurred as the temperature increased above the glass transition temperature. Then, a fast increase in the lamellar repeat period L0 was observed, which is considered as a phase separation process. Whereas the size of the lamellar grain ξ was observed to have rapidly increased in the stage wherein the temperature was held at 230 °C, the L0 was almost constant. This result indicates that the formation of ordered structure in PS-b-PMMA films was mainly determined by two periods: phase separation of block molecules followed by growth of grains in the nanodomain. In addition, it was interesting that the better-order nanodomains were obtained with thermal annealing at a faster heating rate. These findings suggest that accomplishing ordered structure control in a large area could be realized via the design of a proper heating profile.

Using BDS MEO and IGSO Satellite SNR Observations to Measure Soil Moisture Fluctuations Based on the Satellite Repeat Period

Soil moisture is an important geophysical parameter for studying terrestrial water and energy cycles. It has been proven that Global Navigation Satellite System Interferometry Reflectometry (GNSS-IR) can be applied to monitor soil moisture. Unlike the Global Positioning System (GPS) that has only medium earth orbit (MEO) satellites, the Beidou Navigation Satellite System (BDS) also has geosynchronous earth orbit (GEO) satellites and inclined geosynchronous satellite orbit (IGSO) satellites. Benefiting from the distribution of three different orbits, the BDS has better coverage in Asia than other satellite systems. Previous retrieval methods that have been confirmed on GPS cannot be directly applied to BDS MEO satellites due to different satellite orbits. The contribution of this study is a proposed multi-satellite soil moisture retrieval method for BDS MEO and IGSO satellites based on signal-to-noise ratio (SNR) observations. The method weakened the influence of environmental differences in different directions by considering satellite repeat period. A 30-day observation experiment was conducted in Fengqiu County, China and was used for verification. The satellite data collected were divided according to the satellite repeat period, and ensured the response data moved in the same direction. The experimental results showed that the BDS IGSO and MEO soil moisture estimation results had good correlations with the in situ soil moisture fluctuations. The BDS MEO B1I estimation results had the best performance; the estimation accuracy in terms of correlation coefficient was 0.9824, root mean square error (RMSE) was 0.0056 cm3cm−3, and mean absolute error (MAE) was 0.0040 cm3cm−3. The estimations of the BDS MEO B1I, MEO B2I, and IGSO B2I performed better than the GPS L1 and L2 estimations. For the BDS IGSO satellites, the B1I signal was more suitable for soil moisture retrieval than the B2I signal; the correlation coefficient was increased by 19.84%, RMSE was decreased by 42.64%, and MAE was decreased by 43.93%. In addition, the BDS MEO satellites could effectively capture sudden rainfall events.