Tax Evasion and Missing Imports: Evidence From Transaction-Level Data

It is well documented in the literature that developing countries raise less tax revenue as a share of their economy than their developed counterparts. Part of this gap can be explained by the relatively higher tax evasion in the former. Recent literature shows that increasing the availability of information reduces evasion, by increasing the probability of detection. However, there is little evidence to show how tax evasion responds to changes in tax rates. Using highly disaggregated trade data, we show that there is more tax evasion when tax rates increase. However, this relationship only holds when we use the de facto effective tax rate, rather than the de jure effective tax rate. We also find that evasion takes place through under-reporting of the value of imports, as well as mislabelling highly-taxed products as similar lower-taxed products. Finally, we show that when trade costs are ignored, the level of evasion is underestimated; the degree of underestimation in the elasticity estimate depends on the way the trade cost is included in the estimation

Can ICTs Increase Tax? Experimental Evidence from Ethiopia

The widespread introduction of information and communication technologies (ICTs) and digitalised data management systems is one of the most important developments among African tax administrations in recent years. However, very little evidence is available on their effectiveness in practice, and how taxpayers respond to these changes. This paper starts filling this gap by reporting three sets of results from Ethiopia.DFIDBill and Melinda Gates Foundatio

Comparative genome-wide analysis of repetitive DNA in the genus Populus L.

Genome skimming was performed, using Illumina sequence reads, in order to obtain a detailed comparative picture of the repetitive component of the genome of Populus species. Read sets of seven Populus and two Salix species (as outgroups) were subjected to clustering using RepeatExplorer (Novák et al. BMC Bioinformatics 11:378 2010). The repetitive portion of the genome ranged from 33.8 in Populus nigra to 46.5% in Populus tremuloides. The large majority of repetitive sequences were long terminal repeat-retrotransposons. Gypsy elements were over-represented compared to Copia ones, with a mean ratio Gypsy to Copia of 6.7:1. Satellite DNAs showed a mean genome proportion of 2.2%. DNA transposons and ribosomal DNA showed genome proportions of 1.8 and 1.9%, respectively. The other repeat types accounted for less of 1% each. Long terminal repeat-retrotransposons were further characterized, identifying the lineage to which they belong and studying the proliferation times of each lineage in the different species. The most abundant lineage was Athila, which showed large differences among species. Concerning Copia lineages, similar transpositional profiles were observed among all the analysed species; by contrast, differences in transpositional peaks of Gypsy lineages were found. The genome proportions of repeats were compared in the seven species, and a phylogenetic tree was built, showing species separation according to the botanical section to which the species belongs, although significant differences could be found within sections, possibly related to the different geographical origin of the species. Overall, the data indicate that the repetitive component of the genome in the poplar genus is still rapidly evolving

Genome-wide analysis of LTR retrotransposon diversity and its impact on the evolution of the genus Helianthus (L.)

Background: Genome divergence by mobile elements activity and recombination is a continuous process that plays a key role in the evolution of species. Nevertheless, knowledge on retrotransposon-related variability among species belonging to the same genus is still limited. Considering the importance of the genus Helianthus, a model system for studying the ecological genetics of speciation and adaptation, we performed a comparative analysis of the repetitive genome fraction across ten species and one subspecies of sunflower, focusing on long terminal repeat retrotransposons at superfamily, lineage and sublineage levels. Results: After determining the relative genome size of each species, genomic DNA was isolated and subjected to Illumina sequencing. Then, different assembling and clustering approaches allowed exploring the repetitive component of all genomes. On average, repetitive DNA in Helianthus species represented more than 75% of the genome, being composed mostly by long terminal repeat retrotransposons. Also, the prevalence of Gypsy over Copia superfamily was observed and, among lineages, Chromovirus was by far the most represented. Although nearly all the same sublineages are present in all species, we found considerable variability in the abundance of diverse retrotransposon lineages and sublineages, especially between annual and perennial species. Conclusions: This large variability should indicate that different events of amplification or loss related to these elements occurred following species separation and should have been involved in species differentiation. Our data allowed us inferring on the extent of interspecific repetitive DNA variation related to LTR-RE abundance, investigating the relationship between changes of LTR-RE abundance and the evolution of the genus, and determining the degree of coevolution of different LTR-RE lineages or sublineages between and within species. Moreover, the data suggested that LTR-RE abundance in a species was affected by the annual or perennial habit of that species

Specific LTR-Retrotransposons Show Copy Number Variations between Wild and Cultivated Sunflowers

The relationship between variation of the repetitive component of the genome and domestication in plant species is not fully understood. In previous work, variations in the abundance and proximity to genes of long terminal repeats (LTR)-retrotransposons of sunflower (Helianthus annuus L.) were investigated by Illumina DNA sequencingtocompare cultivars and wild accessions. In this study, we annotated and characterized 22 specific retrotransposon families whose abundance varies between domesticated and wild genotypes. These families mostly belonged to the Chromovirus lineage of the Gypsy superfamily and were distributed overall chromosomes. They were also analyzed in respect to their proximity to genes. Genes close to retrotransposon were classified according to biochemical pathways, and differences between domesticated and wild genotypes are shown. These data suggest that structural variations related to retrotransposons might have occurred to produce phenotypic variation between wild and domesticated genotypes, possibly by affecting the expression of genes that lie close to inserted or deleted retrotransposons and belong to specific biochemical pathways as those involved in plant stress responses

Les Technologies de l’Information et de la Communication (TIC) peuvent-elles augmenter les taxes? Résultats expérimentaux en Ethiopie

This ICTD Research in Brief is a two-page summary of ICTD Working Paper 82 by Giulia Mascagni, Andualem T. Mengistu, and Firew B. Woldeyes. This series is aimed at policy makers, tax administrators, fellow researchers and anyone else who is big on interest and short on time. African tax administrations have experienced rapid modernisation in the past two decades. The digitalisation of tax records and widespread adoption of ICTs have been key features of this process. However, there is still very little evidence on the effectiveness of ICTs and digitised data on tax collection and the functioning of tax administration more broadly. In principle, ICTs can have a great impact in making the tax administration more efficient. This brief summarises the findings from the working paper that asks the empirical question of whether and to which extent these benefits can materialise in practice, in presence of severe capacity constraints within the tax administration.Résumé du document de travail 82 de Giulia Mascagni, Andualem T. Mengistu, et Firew B. Woldeyes. Les administrations fiscales africaines ont connu une rapide modernisation au cours des deux dernières décennies. La numérisation des dossiers fiscaux et l’adoption généralisée des TIC ont été des éléments majeurs de ce processus. Cependant, il y a encore très peu de preuves de l’efficacité des TIC et des données numérisées sur le recouvrement des impôts et, plus généralement, sur le fonctionnement de l’administration fiscale. En théorie, les TIC peuvent avoir un impact important sur l’augmentation de l’efficacité de l’administration fiscale et sur l’évolution des emplois de tâches mécaniques – comme la saisie des données – vers des tâches plus élaborées – comme les audits et l’analyse de données. En outre, les données numérisées peuvent rendre la mise en œuvre moins coûteuse et plus efficace, en élargissant par exemple l’utilisation des informations issues de sources tierces et par le recoupement systématique des informations des contribuables. Cet article cherche à établir de manière empirique si, et dans quelle mesure, ces avantages peuvent se matérialiser dans la pratique, en présence d’importantes contraintes de capacité au sein de l’administration fiscale

The Singular Evolution of Olea Genome Structure

The current view of plant genome evolution proposes that genome size has mainly been determined by polyploidisation and amplification/loss of transposons, with a minor role played by other repeated sequences, such as tandem repeats. In cultivated olive (Olea europaea subsp. europaea var. europaea), available data suggest a singular model of genome evolution, in which a massive expansion of tandem-repeated sequences accompanied changes in nuclear architecture. This peculiar scenario highlights the importance of focusing on Olea genus evolution, to shed light on mechanisms that led to its present genomic structure. Next-generation sequencing technologies, bioinformatics and in situ hybridisation were applied to study the genomic structure of five related Olea taxa, which originated at different times from their last common ancestor. On average, repetitive DNA in the Olea taxa ranged from ~59% to ~73% of the total genome, showing remarkable differences in terms of composition. Among repeats, we identified 11 major families of tandem repeats, with different abundances in the analysed taxa, five of which were novel discoveries. Interestingly, overall tandem repeat abundance was inversely correlated to that of retrotransposons. This trend might imply a competition in the proliferation of these repeat classes. Indeed, O. paniculata, the species closest to the Olea common ancestor, showed very few tandem-repeated sequences, while it was rich in long terminal repeat retrotransposons, suggesting that the amplification of tandem repeats occurred after its divergence from the Olea ancestor. Furthermore, some tandem repeats were physically localised in closely related O. europaea subspecies (i.e., cultivated olive and O. europaea subsp. cuspidata), which showed a significant difference in tandem repeats abundance. For 4 tandem repeats families, a similar number of hybridisation signals were observed in both subspecies, apparently indicating that, after their dissemination throughout the olive genome, these tandem repeats families differentially amplified maintaining the same positions in each genome. Overall, our research identified the temporal dynamics shaping genome structure during Olea speciation, which represented a singular model of genome evolution in higher plants

Characterisation of LTR-Retrotransposons of Stevia rebaudiana and Their Use for the Analysis of Genetic Variability

Stevia rebaudiana is one of the most important crops belonging to the Asteraceae family. Stevia is cultivated all over the world as it represents a valid natural alternative to artificial sweeteners thanks to its leaves, which produce steviol glycosides that have high sweetening power and reduced caloric value. In this work, the stevia genome sequence was used to isolate and characterise full-length long-terminal repeat retrotransposons (LTR-REs), which account for more than half of the genome. The Gypsy retrotransposons were twice as abundant as the Copia ones. A disproportionate abundance of elements belonging to the Chromovirus/Tekay lineage was observed among the Gypsy elements. Only the SIRE and Angela lineages represented significant portions of the genome among the Copia elements. The dynamics with which LTR-REs colonised the stevia genome were also estimated; all isolated full-length elements turned out to be relatively young, with a proliferation peak around 1–2 million years ago. However, a different analysis conducted by comparing sequences encoding retrotranscriptase showed the occurrence of an older period in which there was a lot of LTR-RE proliferation. Finally, a group of isolated full-length elements belonging to the lineage Angela was used to analyse the genetic variability in 25 accessions of S. rebaudiana using the Inter-Retrotransposon Amplified Polymorphism (IRAP) protocol. The obtained fingerprints highlighted a high degree of genetic variability and were used to study the genomic structures of the different accessions. It was hypothesised that there are four ancestral subpopulations at the root of the analysed accessions, which all turned out to be admixed. Overall, these data may be useful for genome sequence annotations and for evaluating genetic variability in this species, which may be useful in stevia breeding

How an ancient, salt-tolerant fruit crop, Ficus carica L., copes with salinity: a transcriptome analysis

Although Ficus carica L. (fig) is one of the most resistant fruit tree species to salinity, no comprehensive studies are currently available on its molecular responses to salinity. Here we report a transcriptome analysis of F. carica cv. Dottato exposed to 100 mM sodium chloride for 7 weeks, where RNA-seq analysis was performed on leaf samples at 24 and 48 days after the beginning of salinization; a genomederived fig transcriptome was used as a reference. At day 24, 224 transcripts were significantly upregulated and 585 were down-regulated, while at day 48, 409 genes were activated and 285 genes were repressed. Relatively small transcriptome changes were observed after 24 days of salt treatment, showing that fig plants initially tolerate salt stress. However, after an early down-regulation of some cell functions, major transcriptome changes were observed after 48 days of salinity. Seven weeks of 100 mM NaCl dramatically changed the repertoire of expressed genes, leading to activation or reactivation of many cell functions. We also identified salt-regulated genes, some of which had not been previously reported to be involved in plant salinity responses. These genes could be potential targets for the selection of favourable genotypes, through breeding or biotechnology, to improve salt tolerance in fig or other crops

Artificial Intelligence and Surgery: Ethical Dilemmas and Open Issues

Background: Artificial Intelligence (AI) applications aiming to support surgical decision-making processes are generating novel threats to ethical surgical care. To understand and address these threates, we summarize the main ethical issues that may arise from applying AI to surgery, starting from the Ethics Guidelines for Trustworthy Artificial Intelligence framework recently promoted by the European Commission. Study Design: A modified Delphi process has been employed to achieve expert consensus. Results: The main ethical issues that arise from applying AI to surgery, described in detail herein, relate to human agency, accountability for errors, technical robustness, privacy and data governance, transparency, diversity, non-discrimination, and fairness. It may be possible to address many of these ethical issues by expanding the breadth of surgical AI research to focus on implementation science. The potential for AI to disrupt surgical practice suggests that formal digital health education is becoming increasingly important for surgeons and surgical trainees. Conclusions: A multidisciplinary focus on implementation science and digital health education is desirable to balance opportunities offered by emerging AI technologies and respect for the ethical principles of a patient-centric philosophy