Dissimilar Regions Research Articles

Investigation of Damping Effect of PLL on Low-Frequency Harmonic Stability of Grid-Tied Inverter With αβ and dq Current Control Schemes

The choice of phase-locked loop (PLL) bandwidth in three-phase grid-tied inverters (GTIs) is always a tradeoff between robust performance under distorted grid conditions and fast detection of grid voltage phase angle during the low-voltage ride through. Besides, even though both the GTI with decoupled <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dq</i> -frame (CC1) and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\alpha \beta }$ </tex-math></inline-formula> -frame (CC2) current control schemes employ PLL for grid synchronization, and damping effect of PLL, which is a function of its control bandwidth, is not identical. As a consequence, the output impedance of GTI with CC1 and CC2 has diverse interaction scenarios with the weak grid impedance. Therefore, this work investigates the impact of PLL bandwidth on the output impedance of GTI in the two different current control schemes using impedance models in a common frame of reference ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dq</i> -frame here). Negative damping region exhibited by <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${q}$ </tex-math></inline-formula> -axis impedances are identified. It is found that CC2 has a less significant negative damping region, while that of CC1 widens with the increase in PLL bandwidth. Furthermore, the side effects of dissimilar damping regions on inverter-grid system stability are demonstrated through the impedance interaction analysis. The output impedance shaping caused by voltage feedforward and outer power control loops on CC1 and CC2 is also investigated. Finally, a compensator is designed to overcome the phase lag introduced by PLL and voltage feedforward loop. The above findings are validated through MATLAB/Simulink simulations and experiments.

Sequence similarity in 3D for comparison of protein families

Homologous proteins are often compared by pairwise sequence alignment, and structure superposition if the atomic coordinates are available. Unification of sequence and structure data is an important task in structural biology. Here, we present the Sequence Similarity 3D (SS3D) method of integrating sequence and structure information. SS3D is a distance and substitution matrix-based method for straightforward visualization of regions of similarity and difference between homologous proteins. This work details the SS3D approach, and demonstrates its utility through case studies comparing members of several protein families. The examples show that SS3D can effectively highlight biologically important regions of similarity and dissimilarity. We anticipate that the method will be useful for numerous structural biology applications, including, but not limited to, studies of binding specificity, structure-function relationships, and evolutionary pathways. SS3D is available with a manual and tutorial at https://github.com/0x462e41/SS3D/.

Characteristics and Outcomes Among Hospitalized COVID-19-Positive Patients in a Nonurban Environment.

ABSTRACTIntroductionVirtually all hospitalized coronavirus disease-2019 (COVID-19) outcome data come from urban environments. The extent to which these findings are generalizable to other settings is unknown. Coronavirus disease-2019 data from large, urban settings may be particularly difficult to apply in military medicine, where practice environments are often semi-urban, rural, or austere. The purpose of this study is compare presenting characteristics and outcomes of U.S. patients with COVID-19 in a nonurban setting to similar patients in an urban setting.Materials and MethodsThis is a retrospective case series of adults with laboratory-confirmed COVID-19 infection who were admitted to Hershey Medical Center (HMC), a 548-bed tertiary academic medical center in central Pennsylvania serving semi-urban and rural populations, from March 23, 2020, to April 20, 2020 (the first month of COVID-19 admissions at HMC). Patients and outcomes of this cohort were compared to published data on a cohort of similar patients from the New York City (NYC) area.ResultsThe cohorts had similar age, gender, comorbidities, need for intensive care or mechanical ventilation, and most vital sign and laboratory studies. The NYC’s cohort had shorter hospital stays (4.1 versus 7.2 days, P < .001) but more African American patients (23% versus 12%, P = .02) and higher prevalence of abnormal alanine (>60U/L; 39.0% versus 5.9%, P < .001) and aspartate (>40U/L; 58.4% versus 42.4%, P = .012) aminotransferase, oxygen saturation <90% (20.4% versus 7.2%, P = .004), and mortality (21% versus 1.4%, P < .001).ConclusionsHospitalists in nonurban environments would be prudent to use caution when considering the generalizability of results from dissimilar regions. Further investigation is needed to explore the possibility of reproducible causative systemic elements that may help improve COVID-19-related outcomes. Broader reports of these relationships across many settings will offer military medical planners greater ability to consider outcomes most relevant to their unique settings when considering COVID-19 planning.

СТАНОВЛЕНИЕ СИСТЕМЫ ПЕРИОДИЧЕСКОЙ ПЕЧАТИ В ПОЛИЭТНИЧЕСКИХ РЕГИОНАХ В 1900-1930-Е ГОДЫ (на материале прессы Калмыкии и Ставрополья)

The formation of the system of periodicals in two similar and dissimilar polyethnic regions in the south of Russia – Kalmykia and Stavropol – developed according to the same scheme, but had significant nuances. The Stavropol press, aimed at the Russian majority in the region, appeared earlier (in 1850) and was typologically more diverse and numerous until the 1920s, while the publications created for the Kalmyks were for a long time isolated projects: The Russian-Kalmyk Calendar (1911-1918), a newspaper in the Kalmyk language «Oordin ziang» (1917-1918), leaflets and the first bilingual newspaper «Red Kalmyk» (1919-1920). A new stage in the development of journalism in the regions begins with the establishment of Soviet power after the end of the civil war. The work of the press is under the control of the ruling party, and the unification of the system of regional and local periodicals begins. Gradually, both in Kalmykia and in Stavropol, a harmonious system of periodicals was formed, lined up vertically and horizontally: regional / regional mass sociopolitical newspapers – regional / regional youth newspapers – regional / regional children’s newspapers – district / ulus socio-political newspapers – large circulation newspapers – wall newspapers. In addition to newspapers, instructor magazines for party and Soviet workers, literary and artistic publications of regional writers’ unions were published. The polyethnicity of the regions influenced the information policy of local periodicals and the structure of the press: in Kalmykia there were publications in the Kalmyk language, in Russian and bilingual, in Stavropol, along with publications in Russian, there were bilingual publications in two districts.

Interacting with Self-Similarity

Shape similarity is a fundamental problem in geometry processing, enabling applications such as surface correspondence, segmentation, and edit propagation. For example, a user may paint a stroke on one finger of a model and desire the edit to propagate to all fingers. Automatic approaches have difficulty matching user expectations, either due to an algorithm’s inability to guess the scale at which the user is intending to edit or due to underlying deficiencies in the similarity metric (e.g., semantic information not present in the geometry).We propose an approach to interactively design self-similarity maps. We investigate two primitive operations, useful in a variety of scenarios: region and curve similarity. Users select example similar and dissimilar regions. Starting with an automatically generated multi-scale shape signature, our approach solves for a scale parameter and thresholds that group the example regions as specified. We propose a new Smooth Shape Diameter Signature (SSDS) as a more efficient alternative to the Heat or Wave Kernel Signature. If no such parameters can be found, our approach modifies the shape signature itself. Given a curve drawn on the surface, we perform hybrid discrete/continuous optimization to find similar curves elsewhere.We apply our approach for interactive editing scenarios: propagating mesh geometry, patterns duplication, and segmentation.

Where are the bats? An environmental complementarity analysis in a megadiverse country

AbstractAimField surveys are necessary to overcome Wallacean shortfalls. The task is even more important when human pressure on tropical—megadiverse—ecosystems is considered. However, due to financial constraints, spatial and temporal prioritization is required. Here, we used the concept of environmental complementarity to identify non‐surveyed regions for bats that are environmentally different from other already surveyed regions. We highlighted regions in Brazil where field inventories could be conducted to locate new occurrences or even new bat species.LocationBrazil.MethodsWe based our analysis on environmental characterization aiming to identify dissimilar regions to those already sampled for bats in Brazil. We used 21 environmental variables to characterize 1,531 unique localities where bats occur. Then, we applied the parameters of a generalized linear model (GLM) to extrapolate the expected values of the environmental variables for the entire country. We compared the predicted values of localities with newly described bat species occurrence against the values for other bat species.ResultsWe found that sites from which recently discovered species were described are environmentally distinct from the sites where previously described species occur. Therefore, new occurrences and even new species could be found in regions that are environmentally dissimilar from those already surveyed. By crossing the model with a human footprint map, we defined temporal priorities for field inventories. Regions such as the Northern Cerrado and Western Caatinga should be surveyed first. Similar approaches could be undertaken for other biological groups or regions, allowing the identification of spatial congruence and the development of a comprehensive national programme for biological field inventories.Main conclusionNewly described species occurred in environments dissimilar to those previously identified, showing that environmental complementarity analysis is a valid approach to define priority regions for new bat inventories.

Elucidation of cellular targets and exploitation of the receptor-binding domain of SARS-CoV-2 for vaccine and monoclonal antibody synthesis.

The pandemic caused by novel severe acute respiratory syndrome coronavirus (SARS‐CoV‐2) has resulted in over 452 822 deaths in the first 20 days of June 2020 due to the coronavirus virus disease 2019 (COVID‐19). The SARS‐CoV‐2 uses the host angiotensin‐converting enzyme 2 (ACE2) receptor to gain entry inside the human cells where it replicates by using the cell protein synthesis mechanisms. The knowledge of the tissue distribution of ACE2 in human organs is therefore important to predict the clinical course of the COVID‐19. Also important is the understanding of the viral receptor‐binding domain (RBD), a region within the spike (S) proteins, that enables the entry of the virus into the host cells to synthesize vaccine and monoclonal antibodies (mAbs). We performed an exhaustive search of human protein databases to establish the tissues that express ACE2 and performed an in‐depth analysis like sequence alignments and homology modeling of the spike protein (S) of the SARS‐CoV‐2 to identify antigenic regions in the RBD that can be exploited to synthesize vaccine and mAbs. Our results show that ACE2 is widely expressed in human organs that may explain the pulmonary, systemic, and neurological deficits seen in COVID‐19 patients. We show that though the S protein of the SARS‐CoV‐2 is a homolog of S protein of SARS‐CoV‐1, it has regions of dissimilarities in the RBD and transmembrane segments. We show peptide sequences in the RBD of SARS‐CoV‐2 that can bind to the major histocompatibility complex alleles and serve as effective epitopes for vaccine and mAbs synthesis.

A Machine Learning Model to Detect Flow Disturbances during Manufacturing of Composites by Liquid Moulding

In this work, a supervised machine learning (ML) model was developed to detect flow disturbances caused by the presence of a dissimilar material region in liquid moulding manufacturing of composites. The machine learning model was designed to predict the position, size and relative permeability of an embedded rectangular dissimilar material region through use of only the signals corresponding to an array of pressure sensors evenly distributed on the mould surface. The burden of experimental tests required to train in an efficient manner such predictive models is so high that favours its substitution with synthetically-generated simulation datasets. A regression model based on the use of convolutional neural networks (CNN) was developed and trained with data generated from mould-filling simulations carried out through use of OpenFoam as numerical solver. The evolution of the pressure sensors through the filling time was stored and used as grey-level images containing information regarding the pressure, the sensor location within the mould and filling time. The trained CNN model was able to recognise the presence of a dissimilar material region from the data used as inputs, meeting accuracy expectation in terms of detection. The purpose of this work was to establish a general framework for fully-synthetic-trained machine learning models to address the occurrence of manufacturing disturbances without placing emphasis on its performance, robustness and optimization. Accuracy and model robustness were also addressed in the paper. The effect of noise signals, pressure sensor network size, presence of different shape dissimilar regions, among others, were analysed in detail. The ability of ML models to examine and overcome complex physical and engineering problems such as defects produced during manufacturing of materials and parts is particularly innovative and highly aligned with Industry 4.0 concepts.

Statistical and Network-Based Analysis of Italian COVID-19 Data: Communities Detection and Temporal Evolution.

The coronavirus disease (COVID-19) outbreak started in Wuhan, China, and it has rapidly spread across the world. Italy is one of the European countries most affected by COVID-19, and it has registered high COVID-19 death rates and the death toll. In this article, we analyzed different Italian COVID-19 data at the regional level for the period 24 February to 29 March 2020. The analysis pipeline includes the following steps. After individuating groups of similar or dissimilar regions with respect to the ten types of available COVID-19 data using statistical test, we built several similarity matrices. Then, we mapped those similarity matrices into networks where nodes represent Italian regions and edges represent similarity relationships (edge length is inversely proportional to similarity). Then, network-based analysis was performed mainly discovering communities of regions that show similar behavior. In particular, network-based analysis was performed by running several community detection algorithms on those networks and by underlying communities of regions that show similar behavior. The network-based analysis of Italian COVID-19 data is able to elegantly show how regions form communities, i.e., how they join and leave them, along time and how community consistency changes along time and with respect to the different available data.

Hydrogen migration at restructuring palladium\u2013silver oxide boundaries dramatically enhances reduction rate of silver oxide

Heterogeneous catalysts are complex materials with multiple interfaces. A critical proposition in exploiting bifunctionality in alloy catalysts is to achieve surface migration across interfaces separating functionally dissimilar regions. Herein, we demonstrate the enhancement of more than 104 in the rate of molecular hydrogen reduction of a silver surface oxide in the presence of palladium oxide compared to pure silver oxide resulting from the transfer of atomic hydrogen from palladium oxide islands onto the surrounding surface formed from oxidation of a palladium–silver alloy. The palladium–silver interface also dynamically restructures during reduction, resulting in silver–palladium intermixing. This study clearly demonstrates the migration of reaction intermediates and catalyst material across surface interfacial boundaries in alloys with a significant effect on surface reactivity, having broad implications for the catalytic function of bimetallic materials.

Automatic Detection of Dissimilar Regions through Multiple Feature Analysis

Automatic Detection of Dissimilar Regions through Multiple Feature Analysis

Effective Image Quality Inspection Based on Color and Texture Features

As people’s interest in software increases, the number and types of newly developed applications increase day by day. Therefore, there are attempts to automatically check whether the newly developed interface of these programs works correctly through image processing instead of manually. In this paper, we describe a strategy to robustly detect execution error screens of applications through comparative analysis of key features from various kinds of image scenes. In the approach described in this study, we extract the main multiple features representing the image. Then, by comparing the difference of the extracted multiple features, it is effectively determined whether the image is the same normal image as the reference image or an error image similar to the target image but different from each other. Experimental results verify that the described algorithm accurately detects normal and faulty images by comparing the main multiple features from various types of images. For performance evaluation, we quantitatively compared the performance of the introduced dissimilar region extraction strategy with those of other conventional methods. The existing methods of extracting similarity between images based on one feature or histogram comparison mostly lack information to sufficiently express the entire image. Therefore, when similar areas between two images are extracted, many errors occurred due to incorrect matching. However, the proposed multiple feature-based method obtains richer information by extracting multiple features from the input image. In addition, because the matching is done based on this information, the accuracy is relatively high. The approach introduced in this study is expected to be effectively used in many practical applications related to image processing such as image retrieval, trademark comparison, video security, application quality inspection, etc.

Leaps and bounds: geographical and ecological distance constrained the colonisation of the Afrotemperate by Erica

BackgroundThe coincidence of long distance dispersal (LDD) and biome shift is assumed to be the result of a multifaceted interplay between geographical distance and ecological suitability of source and sink areas. Here, we test the influence of these factors on the dispersal history of the flowering plant genus Erica (Ericaceae) across the Afrotemperate. We quantify similarity of Erica climate niches per biogeographic area using direct observations of species, and test various colonisation scenarios while estimating ancestral areas for the Erica clade using parametric biogeographic model testing.ResultsWe infer that the overall dispersal history of Erica across the Afrotemperate is the result of infrequent colonisation limited by geographic proximity and niche similarity. However, the Drakensberg Mountains represent a colonisation sink, rather than acting as a “stepping stone” between more distant and ecologically dissimilar Cape and Tropical African regions. Strikingly, the most dramatic examples of species radiations in Erica were the result of single unique dispersals over longer distances between ecologically dissimilar areas, contradicting the rule of phylogenetic biome conservatism.ConclusionsThese results highlight the roles of geographical and ecological distance in limiting LDD, but also the importance of rare biome shifts, in which a unique dispersal event fuels evolutionary radiation.

The economics of phosphorus supplementation of beef cattle grazing northern Australian rangelands

Context Phosphorus (P) deficiency occurs in beef cattle grazing many rangeland regions with low-P soils, including in northern Australia, and may severely reduce cattle productivity in terms of growth, reproductive efficiency and mortality. However, adoption of effective P supplementation by cattle producers in northern Australia is low. This is likely to be due to lack of information and understanding of the profitability of P supplementation where cattle are P-deficient. Aims The profitability of P supplementation was evaluated for two dissimilar regions of northern Australia, namely (1) the Katherine region of the Northern Territory, and (2) the Fitzroy Natural Resource Management (NRM) region of central Queensland. Methods Property-level, regionally relevant herd models were used to determine whole-of-business productivity and profitability over 30 years. The estimated costs and benefits of P supplementation were obtained from collation of experimental data and expert opinion of persons with extensive experience of the industry. The economic consequences of P supplementation at the property level were assessed by comparison of base production without P supplementation with the expected production of P-supplemented herds, and included the implementation phase and changes over time in herd structure. In the Katherine region, it was assumed that the entire cattle herd (breeders and growing cattle) grazed acutely P-deficient land types and the consequences of (1) no P supplementation, or P supplementation during (2) the dry season, or (3) both the wet and dry seasons (i.e. 3 scenarios) were evaluated. In the Fitzroy NRM region, it was assumed that only the breeders grazed P-deficient land types with three categories of P deficiency (marginal, deficient and acutely deficient), each with either (1) no P supplementation, or P supplementation during (2) the wet season, (3) the dry season, or (4) both the wet and dry seasons (i.e. 12 scenarios). Key results In the Katherine region, year-round P supplementation of the entire cattle herd (7400 adult equivalents) grazing acutely P-deficient pasture resulted in a large increase in annual business profit (+AU$500000). Supplementing with P (and N) only in the dry season increased annual business profit by +AU$200000. In the Fitzroy NRM region, P supplementation during any season of the breeder herd grazing deficient or acutely P-deficient pastures increased profit by +AU$2400–AU$45000/annum (total cattle herd 1500 adult equivalents). Importantly, P supplementation during the wet season-only resulted in the greatest increases in profit within each category of P deficiency, comprising +AU$5600, AU$6300 and AU$45000 additional profit per annum for marginal, deficient and acutely P-deficient herds respectively. Conclusions The large economic benefits of P supplementation for northern beef enterprises estimated in the present study substantiate the current industry recommendation that effective P supplementation is highly profitable when cattle are grazing P-deficient land types. Implications The contradiction of large economic benefits of P supplementation and the generally low adoption rates by the cattle industry in northern Australia suggests a need for targeted research and extension to identify the specific constraints to adoption, including potential high initial capital costs.

Content-based search of earth observation data archives using open-access multitemporal land cover and terrain products

Public Earth Observation (EO) data archives, e.g., MODIS, Landsat, and Sentinels, are valuable sources of information for a broad range of applications. For decision-supporting applications used in urban planning, land management, and sustainable development, images covering regions similar to the study area are prerequisites for high-accuracy decision making. These desirable images cannot be quickly searched for in the EO data archives via image metadata alone but can be obtained through content-based image retrieval methods. Land cover (LC) information, traditionally obtained through image segmentation or classification processing, is typically used in existing methods. Image processing is time consuming and has various accuracy levels for heterogeneous images, thus decreasing retrieval efficiency and accuracy. Additionally, the monotemporal LC information used has a limited ability to distinguish among confusable regions with different terrain, e.g., forests located on flatlands or mountains, and to obtain regions, e.g., urban regions, with similar growth rates. In this study, we employ free multiple-year 30 m LC products, a terrain product, and the Google Earth Engine (GEE) platform to accurately and efficiently locate the desired heterogeneous moderate spatial resolution images from various public EO data archives. Regions similar to the query region are detected with two-stage similarity calculations: First, monotemporal pixel-based LC and terrain information are used to filter out the most dissimilar regions; second, object-based LC change and terrain information are used to locate similar regions. Then, the desired images covering these detected similar regions are obtained from EO data archives via image metadata, e.g., geographical location and acquisition time. The experimental results of the two representative query regions show that our method can be used to obtain the desired images within several minutes and has higher accuracy than the LandEx method and a simplified method using only monotemporal LC information. The main contribution of our study is to reveal that LC changes and terrain information are helpful for improving the retrieval accuracy achieved from monotemporal LC information alone. Our method has great operability, with no need to perform EO data acquisition, image processing of raw EO images, or management of computational resources. Our method is conducive to making full use of images in various public EO archives to improve the decision making quality of decision-supporting applications.

Dynamic and structural differences between heme oxygenase-1 and -2 are due to differences in their C-terminal regions

Heme oxygenase (HO) catalyzes heme degradation, a process crucial for regulating cellular levels of this vital, but cytotoxic, cofactor. Two HO isoforms, HO1 and HO2, exhibit similar catalytic mechanisms and efficiencies. They also share catalytic core structures, including the heme-binding site. Outside their catalytic cores are two regions unique to HO2: a 20-amino acid-long N-terminal extension and a C-terminal domain containing two heme regulatory motifs (HRMs) that bind heme independently of the core. Both HO isoforms contain a C-terminal hydrophobic membrane anchor; however, their sequences diverge. Here, using hydrogen-deuterium exchange MS, size-exclusion chromatography, and sedimentation velocity, we investigated how these divergent regions impact the dynamics and structure of the apo and heme-bound forms of HO1 and HO2. Our results reveal that heme binding to the catalytic cores of HO1 and HO2 causes similar dynamic and structural changes in regions (proximal, distal, and A6 helices) within and linked to the heme pocket. We observed that full-length HO2 is more dynamic than truncated forms lacking the membrane-anchoring region, despite sharing the same steady-state activity and heme-binding properties. In contrast, the membrane anchor of HO1 did not influence its dynamics. Furthermore, although residues within the HRM domain facilitated HO2 dimerization, neither the HRM region nor the N-terminal extension appeared to affect HO2 dynamics. In summary, our results highlight significant dynamic and structural differences between HO2 and HO1 and indicate that their dissimilar C-terminal regions play a major role in controlling the structural dynamics of these two proteins.

Hyperspectral band selection using the N-dimensional Spectral Solid Angle method for the improved discrimination of spectrally similar targets

Selecting a subset of bands from hyperspectral data can improve the discrimination of ground targets because the most distinguishing spectral features are utilized. Targets with similar spectra are particularly challenging for band selection. A band selection method using the N-dimensional Solid Spectral Angle (NSSA) was recently proposed by Tian et al. (2016) to select the most dissimilar spectral regions amongst targets, but no case studies have been conducted using data from natural targets and there are currently no guidelines for the parameter selection in the NSSA band selection method. This study uses two spectral datasets of geologic relevance (clay minerals and ultramafic rocks), each with spectrally similar materials, to establish guidelines for the selection of two parameters (k and threshold) that will enable the use of the method for practical applications. K defines the band interval (relates to feature width) from which NSSA is calculated, and the threshold defines the number of bands selected from a profile of NSSA as a function of wavelength. The first guideline consists in constraining the maximum k value based on the spectral dimensionality of the widest significant spectral feature for the materials under study. The second guideline is to use a profile of the NSSA value as a function of wavelength for each permissible k value to capture the primary wavelength regions of high NSSA values. Finally, the threshold parameter for each k is estimated from a graph of the NSSA value as a function of the number of bands. The guidelines on the parameter definition allow non-expert users to select a subset of bands while capturing both narrow and broad discriminating features.Results show that bands selected from the two datasets are in good agreement with known spectral features. Of significance is that the bands encompass a range of distinguishing and often subtle spectral characteristics that include absorption feature position, and shape (asymmetry) and depth, the same that are recognized by experts, and thus can be used to assist experts in identifying key features. Moreover, the bands selected with NSSA show improved class separation as illustrated for datasets of spectrally similar materials. When tested for the discrimination of clay minerals, a competitive method named Variable Number Variable Band Selection (VNVBS) did not provide adequate information for the selection of bands. There are several valuable band selection methods reported in the literature, but few can be applied to datasets encompassing a relatively small number of spectra and to select bands that enable the discrimination of spectrally similar materials. As demonstrated in this study, the NSSA method should be of great value to studies that require feature identification from spectral libraries either resulting from the collection of field spectra or the extraction of endmembers from imagery.

The impact of seasonality on multi-scale feature extraction techniques

ABSTRACTA key component in constructing a broad-scale, gridded population dataset is fine resolution geospatial data accurately depicting the extent of human activity. Analogous datasets are often developed using a wide range of methods and classification techniques, including the use of spatial features, spectral features, or the coupling of both to identify the presence of man-made structures from high-resolution satellite imagery. By using spatial and textural-based descriptors to generate high-resolution settlement layers for two dissimilar regions at the peak of seasonal disparity, this study attempts to quantify the influence of seasonality on the accuracy of a supervised, multi-scale, feature extraction framework for automated delineation of human settlement. Results generated by numerous models are evaluated against a reference dataset allowing for assessment of seasonal and feature differences in the context of accuracy. Global or regional mapping of human settlement requires the assemblage of high-resolution satellite images with variegated acquisition characteristics (season, sun elevation, off-nadir, etc.) to produce a cloud-free composite image from which features are extracted. Results of this study suggest an emphasis on imagery criteria, in particular acquisition date, could improve classification accuracy when mapping human settlement at scale.

A longitudinal magnetic resonance spectroscopy study investigating effects of risperidone in the anterior cingulate cortex and hippocampus in schizophrenia

Magnetic Resonance Spectroscopy is a popular approach to probe brain chemistry in schizophrenia (SZ), but no consensus exists as to the extent of alterations. This may be attributable to differential effects of populations studied, brain regions examined, or antipsychotic medication effects. Here, we measured neurometabolites in the anterior cingulate cortex (ACC) and hippocampus, two structurally dissimilar brain regions implicated in the SZ pathophysiology. We enrolled 61 SZ with the goal to scan them before and after six weeks of treatment with risperidone. We also scanned 31 matched healthy controls twice, six weeks apart. Using mixed effect repeated measures linear models to examine the effect of group and time on metabolite levels in each voxel, we report an increase in hippocampal glutamate + glutamine (Glx) in SZ compared to controls (p = 0.043), but no effect of antipsychotic medication (p = 0.330). In the ACC, we did not find metabolite alterations or antipsychotic medication related changes after six weeks of treatment with risperidone. The coefficients for the discriminant function (differentiating SZ from HC) in the ACC were greatest for NAA (−0.83), and in the hippocampus for Glx (0.76), the same metabolites were associated with greater treatment response in patients at trend level. Taken together, our data extends the existing literature by demonstrating regionally distinct metabolite alterations in the same patient group and suggests that antipsychotic medications may have limited effects on metabolite levels in these regions.

Multi-plane time-resolved Particle Image Velocimetry (PIV) flow field measurements in an optical Spark-Ignition Direct-Injection (SIDI) engine for Large-Eddy Simulation (LES) model validations

In-cylinder flow characteristics play a significant role in the fuel–air mixing process of Spark-Ignition Direct-Injection (SIDI) engines. Typically, planar Particle Image Velocimetry (PIV) is used to measure a representative velocity field sectioning through the center plane of the engine cylinder. However, a single flow field offers very limited perspective regarding the Three-Dimensional nature of the flow fields. Since the in-cylinder flow is stochastically complex, large datasets of flow field measurements along multiple planes are needed to provide a complete panoramic understanding of the flow dynamics. In this study, a high-speed PIV is applied to measure the crank-angle resolved flow fields inside a single-cylinder four-valve optical SIDI engine. Five flow fields along different tumble planes are captured. These five planes include two orthogonal planes cutting through the spark plug tip, two parallel planes sectioning through middle point of the intake and exhaust valves, and one plane through the centers of two intake valves. In addition, numerical computations are carried out with Large-Eddy Simulation (LES) model in CONVERGE. With the guidance from multi-plane PIV measurements, a novel validation approach is proposed in this study. The quantitative analysis and comparison between LES simulations and PIV experiments are divided in terms of global and local comparison indices. The global comparison indices provide a quantitative single value to quickly check the overall similarity of velocity directions and magnitudes between PIV and LES results of a specific individual plane. The local comparison indices further evaluate the similarity between the flow fields of LES and PIV point by point to identify any dissimilar regions and vortex features, which are likely to indicate the complex flow structures at low-speed regions. In summary, not only can the combined data analysis approach provide a reliable way for LES model validations, it can also reveal the physical quantifications of the complex in-cylinder flow characteristics.