Enhancing Surface Soil Moisture Estimation through Integration of Artificial Neural Networks Machine Learning and Fusion of Meteorological, Sentinel-1A and Sentinel-2A Satellite Data

For many environmental and agricultural applications, an accurate estimation of surface soil moisture is essential. This study sought to determine whether combining Sentinel-1A, Sentinel-2A, and meteorological data with artificial neural networks (ANN) could improve soil moisture estimation in various land cover types. To train and evaluate the model’s performance, we used field data (provided by La Tuscia University) on the study area collected during time periods between October 2022, and December 2022. Surface soil moisture was measured at 29 locations. The performance of the model was trained, validated, and tested using input features in a 60:10:30 ratio, using the feed-forward ANN model. It was found that the ANN model exhibited high precision in predicting soil moisture. The model achieved a coefficient of determination (R2) of 0.71 and correlation coefficient (R) of 0.84. Furthermore, the incorporation of Random Forest (RF) algorithms for soil moisture prediction resulted in an improved R2 of 0.89. The unique combination of active microwave, meteorological data and multispectral data provides an opportunity to exploit the complementary nature of the datasets. Through preprocessing, fusion, and ANN modeling, this research contributes to advancing soil moisture estimation techniques and providing valuable insights for water resource management and agricultural planning in the study area

Tetrameric Structure of Centromeric Nucleosomes in Interphase Drosophila Cells

Centromeres, the specialized chromatin structures that are responsible for equal segregation of chromosomes at mitosis, are epigenetically maintained by a centromere-specific histone H3 variant (CenH3). However, the mechanistic basis for centromere maintenance is unknown. We investigated biochemical properties of CenH3 nucleosomes from Drosophila melanogaster cells. Cross-linking of CenH3 nucleosomes identifies heterotypic tetramers containing one copy of CenH3, H2A, H2B, and H4 each. Interphase CenH3 particles display a stable association of approximately 120 DNA base pairs. Purified centromeric nucleosomal arrays have typical “beads-on-a-string” appearance by electron microscopy but appear to resist condensation under physiological conditions. Atomic force microscopy reveals that native CenH3-containing nucleosomes are only half as high as canonical octameric nucleosomes are, confirming that the tetrameric structure detected by cross-linking comprises the entire interphase nucleosome particle. This demonstration of stable half-nucleosomes in vivo provides a possible basis for the instability of centromeric nucleosomes that are deposited in euchromatic regions, which might help maintain centromere identity

ATP-Dependent Chromatin Remodeling Factors and Their Roles in Affecting Nucleosome Fiber Composition

ATP-dependent chromatin remodeling factors of the SNF2 family are key components of the cellular machineries that shape and regulate chromatin structure and function. Members of this group of proteins have broad and heterogeneous functions ranging from controlling gene activity, facilitating DNA damage repair, promoting homologous recombination to maintaining genomic stability. Several chromatin remodeling factors are critical components of nucleosome assembly processes, and recent reports have identified specific functions of distinct chromatin remodeling factors in the assembly of variant histones into chromatin. In this review we will discuss the specific roles of ATP-dependent chromatin remodeling factors in determining nucleosome composition and, thus, chromatin fiber properties

Developing a satellite based automatic system for crop monitoring: Kenya's Great Rift valley, a case study

The crop growth stage represents essential information for agricultural areas management. In this study we investigate the feasibility of a tool based on remotely sensed satellite (Landsat 8) imagery, capable of automatically classify crop fields and how much resolution enhancement based on pan-sharpening techniques and phenological information extraction, useful to create decision rules that allow to identify semantic class to assign to an object, can effectively support the classification process. Moreover we investigate the opportunity to extract vegetation health status information from remotely sensed assessment of the equivalent water thickness (EWT). Our case study is the Kenya's Great Rift valley, in this area a ground truth campaign was conducted during August 2015 in order to collect crop fields GPS measurements, leaf area index (LAI) and chlorophyll sample

An improved method of soil moisture meter calibration for satellite data validation at watershed scale

This work presents an improved gravimetric algorithm to derive reference soil moisture, with removal of some of the hypothesis on which its original expression was based, and addition of a new corrective term that takes into account the interdependence between temperature and non-unitary water density. The temperature correction term improves reference measurements by up to 0.55% of their values in the temperature range 10–35℃. The temperature-corrected reference measurements were applied to the calibration of a hand-held soil moisture meter (Lutron PMS-714) for three soil texture types: medium, fine, and very fine. Linear regression models were used to calibrate the meter for each soil type, and the resulting calibration equations were validated with field data sampled from Sondu-Miriu watershed in Western Kenya. The validation produced errors (RMSE = 0.022, 0.010, 0.010 m3/m3) that are significantly better than the meter’s reported factory calibration errors of ± 0.05 m3/m3. While calibrations did not improve correlation statistics (R2 and RMSE), they did significantly reduce biases (+ 0.009, + 0.004, -0.001 m3/m3) compared to uncalibrated ones (-0.216, -0.181, -0.184 m3/m3). Additionally, the calibrated meter values compared well with Soil Moisture Active Passive (SMAP) surface moisture data, with errors (RMSE = 0.010, 0.007, 0.008 m3/m3) well within SMAP recommended value of ± 0.04 m3/m3. A spatial scalability test showed that the calibrations are adequately robust (with R2 = 0.81, RMSE = 0.016 m3/m3, and Bias = + 0.005 m3/m3), permitting calibration equations derived from one site to be scaled out to other sites of similar soil texture regime.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Optical and Laser Remote Sensin

A study on the response of the Equatorial Ionization Anomaly over the East Africa sector during the geomagnetic storm of November 13, 2012

Using a set of up to 12 International GNSS Services (IGS) receivers around the East African region, we present the formation of the peak of ionospheric Equatorial Ionization Anomaly during the geomagnetic storm of 13th November 2012. The diurnal pattern of total electron content (TEC) shows a strong negative storm during the main phase of the storm. Latitudinal variation of TEC shows development of strong Equatorial Ionization Anomaly (EIA) on the recovery phase. Evidence in terms of magnetic variations during the storm period, indicates that the penetration of interplanetary electric fields is the main cause of the negative ionospheric effect during the main phase of the storm. Observation shows the occurrence of very strong westward electric fields arising from the IMF Bz turning southward a few hours after sunset local time. TEC enhancement during the recovery phase on the 16th are attributed to the increased ionospheric disturbance dynamo electric fields. In addition the EIA crest was found to intensify in amplitude as well as expand in latitudinal extent

Dealing with revered past

Research Summary This paper examines how strategy‐makers attempt to reconcile change initiatives with organizational values and principles laid out long before, still encased in strategic identity statements such as corporate mottos and philosophies. It reveals three discursive strategies that strategy‐makers use to establish a sense of continuity in time of change: elaborating (transferring part of the content of the historical statement into a new one), recovering (forging a new statement based on the retrieval and re‐use of historical references), and decoupling (allowing the co‐existence of the historical statement and a contemporary one). By so doing, our study advances research on uses of the past, establishes important linkages between identity and strategy research, and enhances our understanding of the intergenerational transfer of values in family firms. Managerial Summary Crafting a new corporate philosophy or mission statement can help implement strategic change, but can also be experiencedas a disruption in people's sense of “who we are” as an organization. This paper reveals a variety of strategies that managers can use to deal with the tension between promoting change and maintaining a sense of continuity with a distant, revered past. By doing so, it helps managers confronting these issues deal with the enabling and constraining effects of the past. While this is a more general challenge for organizations with historical legacies, it is a particularly delicate issue for family firms grappling with the need to transfer values from one generation to the next, while retaining flexibility to change and adapt over time.Peer reviewe