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The identification and management of low parasitemia infections have become increasingly challenging for malaria control and elimination. Submicroscopic Plasmodium infections and G6PD deficiency among febrile patients require more sensitive diagnostic methods to improve detection and careful treatment regime of these infections. In Ethiopia, information on the low density submicroscopic malarial infections and frequency of G6PD deficiency (G6PDd) is scarce. In this study, 297 malaria suspected febrile patient samples were collected from health facilities of Bonga town in southwestern Ethiopia. The positivity rates of Plasmodium infection were determined by microscopy and quantitative PCR. G6PD activity level was determined by careSTART(™) G6PD biosensor and the frequency of three common variants: G6PD*A (A376G), G6PD*A− (G202A) and Mediterranean (C563T) were investigated. G6PD gene sequencing was performed to detect mutations in exons 2–11 for both G6PD normal and deficient samples based on the phenotypic assay. More than twice Plasmodium infected samples was detected by qPCR (52/297; 17.4%) than microscopy (21/297; 7.0%). About 31 (10%) of the infections were submicroscopic. Bednet usage and age had a significant association with Plasmodium infection. Of the 271 participants who were tested for G6PD phenotype, 19 (7.0%) had low G6PD level. No mutations were observed in A376G, G202A, and C563T in the G6PDd samples, but three novel non-synonymous mutations in exon 2 including a C to T transition at position ChrX:6504 (Arg to Thr), G to T at ChrX:6369 (Ser to IIe), and G to C at ChrX:6664 (Gln to His) were detected. A high number of submicroscopic Plasmodium infections observed in this study pose a challenge for accurate and timely diagnosis, which could hinder malaria control efforts. G6PD deficiency in malaria patients pose danger when treating patients with primaquine. The three novel mutations detected in exon 2 of the G6PD gene merit further investigation on the hemolytic risk when exposed to oxidative antimalarials, their prevalence, and clinical significance.

The identification and management of low parasitemia infections have become increasingly challenging for malaria control and elimination. Submicroscopic Plasmodium infections and G6PD deficiency among febrile patients require more sensitive diagnostic methods to improve detection and careful treatment regime of these infections. In Ethiopia, information on the low density submicroscopic malarial infections and frequency of G6PD deficiency (G6PDd) is scarce. In this study, 297 malaria suspected febrile patient samples were collected from health facilities of Bonga town in southwestern Ethiopia. The positivity rates of Plasmodium infection were determined by microscopy and quantitative PCR. G6PD activity level was determined by careSTART™ G6PD biosensor and the frequency of three common variants: G6PD*A (A376G), G6PD*A− (G202A) and Mediterranean (C563T) were investigated. G6PD gene sequencing was performed to detect mutations in exons 2–11 for both G6PD normal and deficient samples based on the phenotypic assay. More than twice Plasmodium infected samples was detected by qPCR (52/297; 17.4%) than microscopy (21/297; 7.0%). About 31 (10%) of the infections were submicroscopic. Bednet usage and age had a significant association with Plasmodium infection. Of the 271 participants who were tested for G6PD phenotype, 19 (7.0%) had low G6PD level. No mutations were observed in A376G, G202A, and C563T in the G6PDd samples, but three novel non-synonymous mutations in exon 2 including a C to T transition at position ChrX:6504 (Arg to Thr), G to T at ChrX:6369 (Ser to IIe), and G to C at ChrX:6664 (Gln to His) were detected. A high number of submicroscopic Plasmodium infections observed in this study pose a challenge for accurate and timely diagnosis, which could hinder malaria control efforts. G6PD deficiency in malaria patients pose danger when treating patients with primaquine. The three novel mutations detected in exon 2 of the G6PD gene merit further investigation on the hemolytic risk when exposed to oxidative antimalarials, their prevalence, and clinical significance.

Background In Ethiopia, an estimated 68 million peoples are at risk of malaria – 60% caused by Plasmodium falciparum and 40% by Plasmodium vivax. The national elimination program has begun a journey since 2016 with a vision to see a malaria-free country by 2030. The radical cure of P. vivax with the drug primaquine is an important component of the elimination strategy. However, Primaquine causes acute hemolytic anemia in glucose-6 phosphate dehydrogenase enzyme deficient cases and is a threat to P. vivax elimination. G6PD is a cytoplasmic enzyme for all human cells that involves in the pentose phosphate pathway of metabolic reaction and protects red blood cells from cellular oxidative damage by detoxifying free radicals. This study is therefore carried out to determine the G6PD deficiency prevalence among malaria-suspected patients in the study sites. Method Health facility-based cross-sectional study was conducted in 2021 at Shele and Lante health centers. A total of 858 self-presented malaria suspected patients were enrolled in this study. The socio-demographic and clinical information of the study participants were collected using a pre-validated questionnaire, entered into Epi Info™ 7 software, and analyzed using SPSS V.20 statistical software. Finger prick blood samples were collected for onsite CareSTART G6PD biosensor analyzer test, dried blood spot (DBS) preparation, and malaria microscopy. The DBS samples are used for molecular confirmation of G6PD deficiency. Results A total of 858 study participants of which 49.3% (423) were males with the median and interquartile age range of 26 and 21 years, respectively were enrolled in the study. Of all the study participants, 14.3%, 9.3%, and 4.1% were microscopy positive for P. falciparum, P. vivax, and mixed parasites, respectively. The phenotypic CareSTART biosensor analyzer G6PD deficiency rate was 4.8% (41/858). Whereas the molecular genotyping result analyzed in selected 13 patients have shown G6PD gene mutation in 10 (76.9%) of the samples. Particularly G267 + 119C/T mutations were seen in 9 of 13 (69.2%), A376G in 3/13 (23.1%), and G1116A in 3/13 (23.1%). In addition, new mutations such as A376T (A◊T) 2/13 (15.4%) and G1116T (G◊T 1/13 (77 %) were also identified. Conclusion and recommendation : The result implied that G6PD deficiency among the study participants is not significantly high. In addition, the G267 + 119C/T mutation was the most frequent variant reported in this study. Therefore, it is recommended to consider hemolysis risk while prescribing the primaquine drug in the study area.

Background Glucose-6-phosphate dehydrogenase (G6PD) is cytosolic enzyme, which has a vital role for the integrity and functioning of red blood cells. Lower activity of this enzyme leads to the occurrence of acute haemolytic anaemia after exposure to oxidative stressors like primaquine. Primaquine is an important drug for the radical cure of Plasmodium vivax and blocking transmission of Plasmodium falciparum, and thereby enhancing malaria elimination. However, there is a need to identify G6PD deficient individuals and administer the drug with caution due to its haemolytic side effects. The main objective of this study is to determine the prevalence of G6PD deficiency among malaria-suspected individuals. Methods A facility-based cross-sectional study was conducted from September 2020 to September 2021 in Metehara Health Centre, Eastern Ethiopia. A structured questionnaire was used to collect the socio-demographic and clinical information of the study participants. Capillary and venous blood samples were collected based on standard procedures for onsite screening, dried blood spot preparation, and malaria microscopy. The G6PD enzyme activity was measured by careSTART™ G6PD biosensor analyzer. Data was entered and analysed by SPSS. Results A total of 498 study participants were included in the study, of which 62% (309) were males. The overall prevalence of G6PD deficiency based on the biosensor screening was 3.6% (18/498), of which 2.9% and 4.8% were males and females, respectively. Eleven of the G6PD deficient samples had mutations confirmed by G6PD gene sequencing analysis. Mutations were detected in G267 + 119C/T, A376T, and ChrX:154535443. A significant association was found in sex and history of previous malaria infection with G6PD deficiency. Conclusions The study showed that the G6PD deficient phenotype exists in Metehara even if the prevalence is not very high. G267 + 119C/T mutation is the predominant G6PD variant in this area. Therefore, malaria patient treatment using primaquine should be monitored closely for any adverse effects.

Plasmodium vivax malaria was thought to be rare in Africa, but an increasing number of P. vivax cases reported across Africa and in Duffy-negative individuals challenges this dogma. The genetic characteristics of P. vivax in Duffy-negative infections, the transmission of P. vivax in East Africa, and the impact of environments on transmission remain largely unknown. This study examined genetic and transmission features of P. vivax from 107 Duffy-negative and 305 Duffy-positive individuals in Ethiopia and Sudan. No clear genetic differentiation was found in P. vivax between the 2 Duffy groups, indicating between-host transmission. P. vivax from Ethiopia and Sudan showed similar genetic clusters, except samples from Khartoum, possibly due to distance and road density that inhibited parasite gene flow. This study is the first to show that P. vivax can transmit to and from Duffy-negative individuals and provides critical insights into the spread of P. vivax in sub-Saharan Africa.

Background The glucose-6 phosphate dehydrogenase (G6PD) enzyme is a cytoplasmic enzyme for all human cells, involves in the pentose phosphate pathway of metabolic reaction. It protects red blood cells from cellular oxidative damage by detoxifying free radicals. Primaquine can cause acute hemolytic anemia while administered for the treatment of malaria patients with G6PD deficiency. It is the first-line drug against the pre-erythrocyte stage of P. vivax and the gametocyte stage of P. falciparum. The study aims to determine the G6PD deficiency among malaria-suspected patients. Method A health facility-based cross-sectional study was conducted for a total of 858 self-presented malaria suspected patients in Shele and Lante health centers. A structured questionnaire was used to collect the socio-demographic and clinical information of the study participants. Blood samples were collected for onsite G6PD activity measurement, DBS preparation, and malaria microscopy. The G6PD enzyme activity was measured by the CareSTART G6PD biosensor analyzer. Data was entered and analyzed by using SPSS version 20. Results Among 858 study participants, 49.3% (423) were males. The median age and interquartile range were 26 and 21 years respectively. The median of the G6PD enzyme level was 5.9, and the interquartile range of the G6PD enzyme level was 4.2 respectively. Of the study participants, 14.3%, 9.3%, and 4.1% were infected with P. falciparum, P. vivax, and mixed parasites respectively. The phenotypic G6PD deficiency rate was 4.8% (41/858).The common G6PD mutations identified in the study population were A376G (0.35%), G267 + 119C/T (1.05%), and G1116A (0.35%). Additional mutations such as A376T (A◊T) and G1116T (G◊T) were identified for the first time in Ethiopia. Conclusion The prevalence rate of G6PD deficiency was modest. However, the clinicians have to consider hemolysis risk during primaquine treatment in the study area. G267 + 119C/T was the most frequent variant, although A376G and G1116A were also identified.

Background Glucose-6-phosphate dehydrogenase (G6PD) is cytosolic enzyme which has a vital role for the integrity and functioning of red blood cells. Lower activity of this enzyme leads to the occurrence of acute hemolytic anemia after exposure to oxidative stressors like primaquine. Primaquine is an important drug for the radical cure of plasmodium vivax and blocking transmission of Plasmodium falciparum thereby enhancing malaria elimination. However, there is a need to distinguish G6PD deficient individuals and administer the drug with special care due to its hemolytic side effects. The main objective of this study is to determine the prevalence of G6PD deficiency among malaria-suspected individuals. Methods A cross-sectional study was conducted from September 2020 to September 2021 in Metehara Health Center, Eastern Ethiopia. A structured questionnaire was used to collect the socio-demographic and clinical information of the study participants. Capillary and venous blood samples were collected based on standard procedures for onsite screening tests, DBS preparation and malaria microscopy. The G6PD enzyme activity was measured by careSTARTTM POCT S1. Data was entered and analyzed by using SPSS. Results A total of 498 study participants were included in the study, of which 62% (309) were males. The overall prevalence of G6PD deficiency based on the biosensor screening was 3.6% (18/498). Eleven of the G6PD deficient samples had mutations confirmed by gene sequencing analysis. Mutations were detected in G267+119C/T, A376T, and ChrX: 154535443 target genes. A significant association was found between sex and history of previous malaria infection with G6PD deficiency. Conclusions The study has shown that the G6PD deficient phenotype exists in Metehara even if the prevalence is not very high. G267+119C/T mutation is the predominant G6PD variant reported. Therefore, malaria patient treatment using primaquine should be closely followed up for any adverse effects.

Recent studies indicated that Plasmodium vivax can infect Duffy-negative individuals, but the varied diagnostic and methodological approaches have limited our ability to characterize P. vivax across Africa. Here, we utilized a standardized approach to compare epidemiological and genetic attributes of P. vivax from Botswana, Ethiopia, and Sudan, where Duffy-positive and Duffy-negative individuals coexist. Among 1,215 febrile patients, the proportions of Duffy negativity range from 20-36% in East Africa to 84% in Southern Africa. Considerable differences were observed in P. vivax prevalence among Duffy-negative populations ranging from averaged 9.2% in Sudan to 86% in Botswana. P. vivax parasite density in Duffy-negative infections is significantly lower than in Duffy-positive infections. Phylogenetic analyses of 229 PvDBP sequences indicated that Duffy-negative P. vivax were not monophyletic but occurred in multiple well-supported clades, suggesting independent origins. Duffy-negative Africans are clearly not resistant to P. vivax and the public health significance should no longer be neglected.

In this work, we present a hardware-efficient architecture for pedestrian detection with neuromorphic Dynamic Vision Sensors (DVSs), asynchronous camera sensors that report discrete changes in light intensity. These imaging sensors have many advantages compared to traditional frame-based cameras, such as increased dynamic range, lower bandwidth requirements, and higher sampling frequency with lower power consumption. Our architecture is composed of two main components: an event filtering stage to denoise the input image stream followed by a low-complexity neural network. For the first stage, we use a novel point-process filter (PPF) with an adaptive temporal windowing scheme that enhances classification accuracy. The second stage implements a hardware-efficient Binary Neural Network (BNN) for classification. To demonstrate the reduction in complexity achieved by our architecture, we showcase a Field-Programmable Gate Array (FPGA) implementation of the entire system which obtains a 86& reduction in latency compared to current neural network floating-point architectures.

Plasmodium vivaxmalaria is a neglected tropical disease in Africa due to low occurrence rates and lack of accurate diagnosis. Recently, there has been a dramatic increase inP. vivaxcases in East Africa and reportedly spreading to western countries. This study investigated the geographical origin and genetic diversity ofP. vivaxin Sudan by 14 microsatellite markers. A total of 113 clinicalP. vivaxsamples were collected from two districts, New Halfa and Khartoum in Sudan. In addition, data from 841 geographical samples retrieved from the database for global genetic analysis were included in the analysis to further the genetic relationships among theP. vivaxisolates at regional and worldwide scales. On a regional scale, we observed 91 unique and 8 shared haplotypes amongst the Sudan samples. Such a high genetic diversity compared to other geographical isolates lends support to hypothesis thatP. vivaxwas originated from Africa. On a global scale, as already demonstrated, we observed distinct genetic clustering ofP. vivaxisolates from Africa, South America, and Asia (including Papua New Guinea and Solomon Island) with limited admixture in all three clusters. The principal component analysis and phylogenetic tree showed similar clustering patterns and highlighted the contribution of the African isolates to the genetic variation observed globally. The East AfricanP. vivaxshowed similarity with some of the Asian isolates suggesting potential recent introductions. Our results show extensive genetic diversity co-occurring with significant multi-locus linkage disequilibrium, demonstrating the effectiveness of using microsatellite markers to implement effective control measures.

Plasmodium vivax malaria is much less common in Africa than the rest of the world because the parasite relies primarily on the Duffy antigen/chemokine receptor (DARC) to invade human erythrocytes, and the majority of Africans are Duffy negative. Recently, there has been a dramatic increase in the reporting of P. vivax cases in Africa, with a high number of them being in Duffy negative individuals, potentially indicating P. vivax has evolved an alternative invasion mechanism that can overcome Duffy negativity. Here, we analyzed single nucleotide polymorphism (SNP) and copy number variation (CNV) in Whole Genome Sequence (WGS) data from 44 P. vivax samples isolated from symptomatic malaria patients in southwestern Ethiopia, where both Duffy positive and Duffy negative individuals are found. A total of 123,711 SNPs were detected, of which 22.7% were nonsynonymous and 77.3% were synonymous mutations. The largest number of SNPs were detected on chromosomes 9 (24,007 SNPs; 19.4% of total) and 10 (16,852 SNPs, 13.6% of total). There were particularly high levels of polymorphism in erythrocyte binding gene candidates including merozoite surface protein 1 (MSP1) and merozoite surface protein 3 (MSP3.5, MSP3.85 and MSP3.9). Two genes, MAEBL and MSP3.8 related to immunogenicity and erythrocyte binding function were detected with significant signals of positive selection. Variation in gene copy number was also concentrated in genes involved in host-parasite interactions, including the expansion of the Duffy binding protein gene (PvDBP) on chromosome 6 and MSP3.11 on chromosome 10. Based on the phylogeny constructed from the whole genome sequences, the expansion of these genes was an independent process among the P. vivax lineages in Ethiopia. We further inferred transmission patterns of P. vivax infections among study sites and showed various levels of gene flow at a small geographical scale. The genomic features of P. vivax provided baseline data for future comparison with those in Duffy-negative individuals and allowed us to develop a panel of informative Single Nucleotide Polymorphic markers diagnostic at a micro-geographical scale., Author summary Plasmodium vivax is the most geographically widespread parasite species that causes malaria in humans. Although it occurs in Africa as a member of a mix of Plasmodium species, P. vivax is dominant in other parts of the world outside of Africa (e.g., Brazil). It was previously thought that most African populations were immune to P. vivax infections due to the absence of Duffy antigen chemokine receptor (DARC) gene expression required for erythrocyte invasion. However, several recent reports have indicated the emergence and potential spread of P. vivax across human populations in Africa. Compared to Southeast Asia and South America where P. vivax is highly endemic, data on polymorphisms in erythrocyte binding gene candidates of P. vivax from Africa is limited. Filling this knowlege gap is critical for identifying functional genes in erythrocyte invasion, biomarkers for tracking the P. vivax isolates from Africa, as well as potential gene targets for vaccine development. This paper examined the level of genetic polymorphisms in a panel of 43 potential erythrocyte binding protein genes based on whole genome sequences and described transmission patterns of P. vivax infections from different study sites in Ethiopia based on the genetic variants. Our analyses showed that chromosomes 9 and 10 of the P. vivax genomes isolated in Ethiopia had the most high-quality genetic polymorphisms. Among all erythrocyte binding protein gene candidates, the merozoite surface proteins 1 and merozoite surface protein 3 showed high levels of polymorphism. MAEBL and MSP3.8 related to immunogenicity and erythrocyte binding function were detected with significant signals of positive selection. The expansion of the Duffy binding protein and merozoite surface protein 3 gene copies was an independent process among the P. vivax lineages in Ethiopia. Various levels of gene flow were observed even at a smaller geographical scale. Our study provided baseline data for future comparison with P. vivax in Duffy negative individuals and help develop a panel of genetic markers that are informative at a micro-geographical scale.

We propose the first network to jointly learn visual motion and confidence from events in spatially local patches. Event-based sensors deliver high temporal resolution motion information in a sparse, non-redundant format. This creates the potential for low computation, low latency motion recognition. Neural networks which extract global motion information, however, are generally computationally expensive. Here, we introduce a novel shallow and compact neural architecture and learning approach to capture reliable visual motion information along with the corresponding confidence of inference. Our network makes a prediction of the visual motion at each spatial location using only local events. Our confidence network then identifies which of these predictions will be accurate. In the task of recovering pan-tilt ego velocities from events, we show that each individual confident local prediction of our network can be expected to be as accurate as state of the art optimization approaches which utilize the full image. Furthermore, on a publicly available dataset, we find our local predictions generalize to scenes with camera motions and the presence of independently moving objects. This makes the output of our network well suited for motion based tasks, such as the segmentation of independently moving objects. We demonstrate on a publicly available motion segmentation dataset that restricting predictions to confident regions is sufficient to achieve results that exceed state of the art methods.

Plasmodium vivax invasion of human erythrocytes depends on the Duffy Binding Protein (PvDBP) which interacts with the Duffy antigen. PvDBP copy number has been recently shown to vary between P. vivax isolates in Sub-Saharan Africa. However, the extent of PvDBP copy number variation, the type of PvDBP multiplications, as well as its significance across broad samples are still unclear. We determined the prevalence and type of PvDBP duplications, as well as PvDBP copy number variation among 178 Ethiopian P. vivax isolates using a PCR-based diagnostic method, a novel quantitative real-time PCR assay and whole genome sequencing. For the 145 symptomatic samples, PvDBP duplications were detected in 95 isolates, of which 81 had the Cambodian and 14 Malagasy-type PvDBP duplications. PvDBP varied from 1 to >4 copies. Isolates with multiple PvDBP copies were found to be higher in symptomatic than asymptomatic infections. For the 33 asymptomatic samples, PvDBP was detected with two copies in two of the isolates, and both were the Cambodian-type PvDBP duplication. PvDBP copy number in Duffy-negative heterozygotes was not significantly different from that in Duffy-positives, providing no support for the hypothesis that increased copy number is a specific association with Duffy-negativity, although the number of Duffy-negatives was small and further sampling is required to test this association thoroughly., Author summary Plasmodium vivax invasion of human erythrocytes relies on interaction between the Duffy antigen and P. vivax Duffy Binding Protein (PvDBP). Whole genome sequences from P. vivax field isolates in Madagascar identified a duplication of the PvDBP gene and PvDBP duplication has also been detected in non-African P. vivax-endemic countries. Two types of PvDBP duplications have been reported, termed Cambodian and Malagasy-type duplications. Our study used a combination of PCR-based diagnostic method, a novel quantitative real-time PCR assay, and whole genome sequencing to determine the prevalence and type of PvDBP duplications, as well as PvDBP copy number on a broad number of P. vivax samples in Ethiopia. We found that over 65% of P. vivax isolated from the symptomatic infections were detected with PvDBP duplications and PvDBP varied from 1 to >4 copies. The majority of PvDBP duplications belongs to the Cambodian-type while the Malagasy-type duplications was also detected. For the asymptomatic infections, despite a small sample size, the majority of P. vivax were detected with a single-copy based on both PCR and qPCR assays. There was no significant difference in PvDBP copy number between Duffy-null heterozygote and Duffy-positive homozygote/heterozygote. Further investigation is needed with expanded Duffy-null homozygotes to examine the functional significance of PvDBP expansion.

In the olfactory system, odor percepts retain their identity despite substantial variations in concentration, timing, and background. We propose a novel strategy for encoding intensity-invariant stimuli identity that is based on representing relative rather than absolute values of the stimulus features. Because, in this scheme, stimulus identity depends on relative amplitudes of stimulus features, identity becomes invariant with respect to variations in intensity and monotonous non-linearities of neuronal responses. In the olfactory system, stimulus identity can be represented by the identities of the p strongest responding odorant receptor types out of a species dependent complement. We show that this information is sufficient to recover sparse stimuli (odorants) via elastic net loss minimization. Such a minimization has to be performed under constraints imposed by the relationships between stimulus features. We map this problem onto the dual problem of minimizing a functional of Lagrange multipliers. The dual problem, in turn, can be solved by a neural network whose Lyapunov function represents the dual Lagrangian. We thus propose that networks in the piriform cortex compute odorant identity and implement dual computations with the sparse activities of individual neurons representing the Lagrange multipliers., 10 pages, 1 figure

Plasmodium vivax malaria is a neglected tropical disease, despite being more geographically widespread than any other form of malaria. The documentation of P. vivax infections in different parts of Africa where Duffy-negative individuals are predominant suggested that there are alternative pathways for P. vivax to invade human erythrocytes. Duffy-negative individuals may be just as fit as Duffy-positive individuals and are no longer resistant to P.vivax malaria. In this review, we describe the complexity of P. vivax malaria, characterize pathogenesis and candidate invasion genes of P. vivax, and host immune responses to P. vivax infections. We provide a comprehensive review on parasite ligands in several Plasmodium species that further justify candidate genes in P. vivax. We also summarize previous genomic and transcriptomic studies related to the identification of ligand and receptor proteins in P. vivax erythrocyte invasion. Finally, we identify topics that remain unclear and propose future studies that will greatly contribute to our knowledge of P. vivax.

In the olfactory system, odor percepts retain their identity despite substantial variations in concentration, timing, and background. We propose a novel strategy for encoding intensity-invariant stimuli identity based on representing relative rather than absolute stimulus features. In this scheme, dependence on relative amplitudes of stimulus features makes identity invariant to intensity and monotonous non-linearities of neuronal responses. We propose that the olfactory system represents stimulus identity using the information that a subset of odorant receptor types responds more strongly than all receptor types in the complement set. We show that this information is sufficient to ensure the robust recovery of a sparse stimulus (odorant) via elastic net loss minimization. This minimization is performed under the constraints imposed by the relationships between these two receptor sets. We formulate this problem using its dual Lagrangian. We show that the dual problem can be solved by a neural network whose Lyapunov function represents the dual Lagrangian. We thus propose that networks in the piriform cortex compute odorant identity and implement dual computations with the sparse activities of individual neurons representing Lagrange multipliers.