A Note on Weak Double Dividends

A weak double-dividend is the proposition that the welfare improvement from a tax reform, where environmental taxes are used to lower distorting taxes, must be greater than the welfare improvement from a reform where the environmental taxes are returned in a lump sum fashion. A general consensus has emerged that the weak double-dividend is an uncontroversial idea. We show in this note that a weak double-dividend need not hold in a world with multiple distortions.environmental tax policy, second-best taxation, general equilibrium analysis

Tax Distortions and Global Climate Policy

We consider the efficiency implications of policies to reduce global carbon emissions in a world with pre-existing tax distortions. We first note that the weak double-dividend, the proposition that the welfare improvement from a tax reform where environmental taxes are used to lower distorting taxes must be greater than the welfare improvement from a reform where the environmental taxes are returned in a lump sum fashion, need not hold in a world with multiple distortions. We then present a large-scale computable general equilibrium model of the world economy with distortionary taxation. We use this model to evaluate a number of policies to reduce carbon emissions. We find that the weak double dividend is not obtained in a number of European countries. Results also demonstrate the point that the interplay between carbon policies and pre-existing taxes can differ markedly across countries. Thus one must be cautious in extrapolating the results from a country specific analysis to other countries.

Tax Distortions and Global Climate Policy

We consider the efficiency implications of policies to reduce global carbon emissions in a world with pre-existing tax distortions. We first note that the weak double-dividend, the proposition that the welfare improvement from a tax reform where environmental taxes are used to lower distorting taxes must be greater than the welfare improvement from a reform where the environmental taxes are returned in a lump sum fashion, need not hold in a world with multiple distortions. We then present a large-scale computable general equilibrium model of the world economy with distortionary taxation. We use this model to evaluate a number of policies to reduce carbon emissions. We find that the weak double dividend is not obtained in a number of European countries. Results also demonstrate the point that the interplay between carbon policies and pre-existing taxes can differ markedly across countries. Thus one must be cautious in extrapolating the results from a country specific analysis to other countries.

Economics of using combine harvesters in the mechanized rainfed schemes of eastern Sudan

The effective use of combine harvesters not only needs knowledge about operation requirements, but also needs economic evaluation. The objective of this study was to make economic analysis for combine harvesters used in harvesting mechanized rainfed schemes in eastern Sudan. The data were collected from combine harvesters owners through a comprehensive questionnaire that covered 23 combine harvesters in 2016/2017 season. The collected data included fixed cost items such as purchase price, insurance, shelter and taxes and variable cost items like repair and maintenance, fuel, oil, drivers and supervision. Also, data on harvester working parameters like annual harvested area and working hours, besides custom hiring price and crop yield, were collected. In addition to cost analysis, the breakeven point (BEP), in terms of hectares that have to be harvested annually to cover annual fixed costs; and the payback period (PBP) were calculated. Also, sensitivity analyses were carried out to detect the effect of changing cost parameters on BEP and PBP. The results indicated that the annual harvested area by a combine harvester was found to be 1525 ha in 623 hours. The average fixed cost was found to be 207.5 SDG/ha, which constituted about 16.8% and 68.5% of the purchase price and total operating cost, respectively. Whereas the average variable cost was 95.4 SDG/ha, representing 7.7% and 31.5% of the purchase price and total operating cost, respectively. The results indicated that the depreciation cost was the highest among the fixed cost items and fuel cost was the highest among the variable cost items. The results showed that the average cost for direct harvesting operation was 303 SDG/ha (742.1 SDG/hr). It was found that the BEP was 904 ha and the PBP was 9 years. The sensitivity analysis revealed that increasing the purchase price will increase both the BEP and PBP. The study concluded that the use of a combine harvester in the mechanized rainfed schemes for direct harvesting was profitable for both farmer and investor. When the annual required areas by the combine harvester was satisfied, the estimated profit was 143 SDG/ha. However,it is not advisable to use direct harvesting when crop yield is lower than 450 kg/ha

Mus musculus helgolandicus: insights into their origin. A study based on genetic and morphometrics analysis

Islands are a center of interest in evolutionary biology since the emergence of evolutionary theory itself. They are studied to understand the molecular mechanisms of evolution, adaptation and speciation. Invasive species are of particular interest since they may garner clues and evidence about the processes that took place during the onset of colonization and for understanding mechanisms of adaptation. The aim of this project is to study the evolutionary processes that altogether with isolation shaped the phenotypically known house mouse Mus musculus helgolandicus inhabiting the island of Heligoland. Heligoland is a small island located in the South-East corner of the North Sea and was first colonized by humans in the dawn of the fifteenth century. M. m. helgolandicus were first described by Zimmermann in 1953. Since then they have been thought to form a separate subspecies, which is morphologically different from its continental counterpart M. m. domesticus inhabiting the Western European region. Here, four nuclear diagnostic markers (Abpa, D11 cenB2, Btk and Zfy2 ) and the discriminatory relative tail length (TBLR) were used to differentiate these mice from the other two subspecies M. m. musculus and M. m. domesticus. In addition, the possible routes of colonization and population structure for the invasive mice were investigated using mitochondrial (mt)D-loop DNA sequence and (21) microsatellite loci respectively. Furthermore, whole mtDNA genome was sequenced for 11 individual mice to estimate the onset of colonization on the island from the calculation of mutation frequency in comparison to that of house mouse from Kerguelen archipelago, which has a documented colonization history. Moreover, the whole genome sequence of three individuals was generated and analysed for single nucleotide polymorphisms (SNPs) which were then used along with data for two po- tential source populations from the two subspecies inhabiting Europe to assign the possible patterns of introgression of haplotypes in M. m. helgolandicus. This study also revisits the morphology of M. m. helgolandicus, in particular, the mandible to assign morphological differences among Heligoland mice on one side and among Heligoland and mainland populations on the other side. Based on the results from diagnostic markers, relative tail length, microsatellites and mtDNA analyses, M. m. helgolandicus are predominantly of M. m. domesticus origin. M. m. helgolandicus population on Heligoland exhibited low genetic diversity compared with other populations from the mainland. The mtDNA data shows that there is a major mtDNA haplotype specic to Heligoland and a minor haplotype represented by a single individual presumably introgressed. Hence, there was a single primary colonization into the island a few hundred years ago and more interestingly, the isolated island shows a case of recent migration from the mainland revealing a signal of refractory to immigration. M. m. helgolandicus displays an elongated mandible which is distinctive for Heligoland. Most likely it was acquired by adaptive forces due to diet changes from a novel environment, with particular a shift to carnivory. The genome is highly intermixed with M. m. musculus haplotypes, pointing to a possible hybrid speciation scenario during the colonization phase.Contents iv Acknowledgements vii Zusammenfassung ix Abstract xi Declaration xiii List of Figures xiv List of Tables xvi 1 General introduction 1 1.1 Evolution on islands . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 House mice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.3 The hybrid zone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 1.4 The island of Heligoland . . . . . . . . . . . . . . . . . . . . . . . . . 9 1.5 Possible colonization routes of house mouse into Heligoland . . . . . . 11 1.6 Genetic studies on M. m. heligolandicus . . . . . . . . . . . . . . . . 13 1.7 Aims of the study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 2 Genetic analysis and insights into the origin of M. m. helgolandi- cus 16 2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 2.2 Materials and methods . . . . . . . . . . . . . . . . . . . . . . . . . . 19 2.2.1 Sample collection . . . . . . . . . . . . . . . . . . . . . . . . . 19 2.2.2 DNA extraction . . . . . . . . . . . . . . . . . . . . . . . . . . 20 2.2.3 Diagnostic nuclear markers . . . . . . . . . . . . . . . . . . . . 20 2.2.4 Microsatellite typing . . . . . . . . . . . . . . . . . . . . . . . 21 2.2.5 Microsatellite data analysis . . . . . . . . . . . . . . . . . . . 21 2.2.6 mtDNA control region . . . . . . . . . . . . . . . . . . . . . . 22 2.2.7 Complete mtDNA sequencing . . . . . . . . . . . . . . . . . . 23 2.3 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 2.3.1 Subspecies-diagnostic nuclear markers . . . . . . . . . . . . . . 24 2.3.2 Population genetic diversity . . . . . . . . . . . . . . . . . . . 25 2.3.3 mtDNA analysis . . . . . . . . . . . . . . . . . . . . . . . . . 29 2.3.3.1 mtDNA D-loop . . . . . . . . . . . . . . . . . . . . . 29 2.3.3.2 mtDNA genome . . . . . . . . . . . . . . . . . . . . 31 2.4 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 3 Aspects of Insular evolution and adaptation in the mandible of M. m. helgolandicus 37 3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 3.2 Materials and methods . . . . . . . . . . . . . . . . . . . . . . . . . . 44 3.2.1 Tail measurements and coat coloration . . . . . . . . . . . . . 44 3.2.2 Geometric morphometrics . . . . . . . . . . . . . . . . . . . . 44 3.2.2.1 Animal specimens . . . . . . . . . . . . . . . . . . . 44 3.2.2.2 Specimens preparation . . . . . . . . . . . . . . . . . 45 3.2.2.3 Mandible landmarking . . . . . . . . . . . . . . . . . 45 3.2.2.4 Geometric morphometrics analysis . . . . . . . . . . 47 3.2.2.5 Centroid size . . . . . . . . . . . . . . . . . . . . . . 48 3.2.2.6 Statistical analysis . . . . . . . . . . . . . . . . . . . 49 3.3 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 3.3.1 Mandible size among populations . . . . . . . . . . . . . . . . 50 3.3.2 Mandible shape differentiation . . . . . . . . . . . . . . . . . . 51 3.3.2.1 Mandible shape of the house mouse from Heligoland 51 3.3.2.2 Mandible shape of house mouse between Heligoland and mainland populations . . . . . . . . . . . . . . . 53 3.4 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 4 Patterns of introgression in M. m. helgolandicus 69 4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 4.2 Materials and methods . . . . . . . . . . . . . . . . . . . . . . . . . . 77 4.2.1 Whole genome sequencing . . . . . . . . . . . . . . . . . . . . 77 4.2.1.1 DNA Extraction . . . . . . . . . . . . . . . . . . . . 77 4.2.1.2 DNA Library construction and genome sequencing . 77 4.2.2 Sequence analysis . . . . . . . . . . . . . . . . . . . . . . . . . 78 4.2.2.1 Trimming of the reads . . . . . . . . . . . . . . . . . 78 4.2.2.2 Indexing of the reference genome . . . . . . . . . . . 78 4.2.2.3 Sequence mapping and alignment to the reference genome . . . . . . . . . . . . . . . . . . . . . . . . . 78 4.2.2.4 SNP calling and detection . . . . . . . . . . . . . . . 79 4.2.2.5 Identification of SNPs and analysis of variants . . . . 79 4.2.3 Introgression analysis . . . . . . . . . . . . . . . . . . . . . . . 80 4.2.3.1 Hapmix-Inference of local ancestry in admixed populations . . . . . . . . . . . . . . . . . . . . . . . . . 80 4.2.3.2 Reference data for introgression analysis . . . . . . . 80 4.2.3.3 Patterns of introgression . . . . . . . . . . . . . . . . 81 4.2.3.4 Data visualization and GO of introgressed regions . . 81 4.3 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 4.3.1 Whole genome sequence analysis . . . . . . . . . . . . . . . . 82 4.3.2 Detection of SNPs . . . . . . . . . . . . . . . . . . . . . . . . 82 4.3.3 Genome annotations . . . . . . . . . . . . . . . . . . . . . . . 83 4.3.4 Patterns of introgression . . . . . . . . . . . . . . . . . . . . . 84 4.4 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 5 Concluding remarks 92 References 94 Appendix 111 Affdavit 154 Curriculum Vitae 15

Gene flow and cross-mating in Plasmodium falciparum in households in a Tanzanian village

The diversity of the genes encoding 2 merozoite surface proteins (MSP-1 and MSP-2) of Plasmodium falciparum has been examined in parasites infecting members of 4 households in a village in Tanzania. The polymerase chain reaction (PCR) was used to characterize allelic variants of these genes by the sizes and sequences of regions of tandemly repeated bases in each gene. In each household extensive polymorphism was detected among parasites in the inhabitants and in infected mosquitoes caught in their houses. Similar frequencies of the alleles of these genes were observed in all households. Capture-recapture data indicated that both Anopheles gambiae and A.funestus freely dispersed among households in the hamlet. The results confirm that cross-mating and gene flow occur extensively among the parasites, and are discussed within the context of spatial clustering of natural populations of P. falciparu

Maternal and perinatal mortality and morbidity associated with tuberculosis during pregnancy and the postpartum period: a systematic review and meta-analysis

Ammalife and Elly Appeal (Barts Charity), Charities with a focus on maternal health research in developing countries funded SS. The Charities had no influence on the development, conduct or reporting of this work

The genetic variation of lactase persistence alleles in northeast Africa

Lactase persistence (LP) is a well-studied example of a Mendelian trait under selection in some human groups due to gene-culture co-evolution. We investigated the frequencies of genetic variants linked to LP in Sudanese and South Sudanese populations. These populations have diverse subsistence patterns, and some are dependent on milk to various extents, not only from cows, but also from other livestock such as camels and goats. We sequenced a 316bp region involved in regulating the expression of the LCT gene on chromosome 2, which encompasses five polymorphisms that have been associated with LP. Pastoralist populations showed a higher frequency of LP-associated alleles compared to non-pastoralist groups, hinting at positive selection also in northeast African pastoralists. There was no incidence of the East African LP allele (−14010:C) in the Sudanese groups, and only one heterozygote individual for the European LP allele (−13910:T), suggesting limited recent admixture from these geographic regions. Among the LP variants, the −14009:G variant occurs at the highest frequency among the investigated populations, followed by the −13915:G variant, which is likely of Middle Eastern origin, consistent with Middle Eastern gene-flow to the Sudanese populations. The Beja population of the Beni Amer show three different LP-variants at substantial and similar levels, resulting in one of the greatest frequencies of LP-variants among all populations across the world.Competing Interest StatementThe authors have declared no competing interest.Introduction Results and Discussion - Allele frequencies - Haplotype Structure - Selection Scan Conclusion Materials and Methods - Phasing and imputation to analyze haplotype structure - Locus specific branch length (LSBL

Hill- Piper diagram for drinking water quality in Ingessana area - Blue Nile State, Sudan.

        This study, aims to assess the effect of mineralization on drinking water quality and its visages in Ingessana area, which is located in the southwestern part of the Blue Nile State (Sudan). Forty drinking water samples from various sources in the study area were collected during four seasons, and then analyzed, using atomic absorption spectrometer, Flame photometer, UV spectrophotometer and conventional titration methods. Different computer software's were used to interpret data as Aquachem. The results showed that calcium, and magnesium, were the main predominant cations in the samples, while bicarbonate and chloride were the dominant anions in wet and dry seasons. Calcium, magnesium and bicarbonate are due to the presence of marble, calcite CaCO3, dolomite CaCO3, Mg (CO3), aragonite, gabbros, and schist in under saturated state. Calcium chloride and bicarbonate indicate the presence of dolomite, aragonite, halite (NaCl), magnsite, gypsum and carbonate rocks as an interfere layers in the study area. These minerals occur in the fractured zone in study area. The Hill-Piper result shows that, all groundwater visages in wet seasons are normal earth alkaline and alkaline with prevailing bicarbonate, while in dry season is earth alkaline with increased portion of alkalis in water and the processes that control these visages are ion exchange and simple dissolution or mixing processes. Comparing the results with (WHO) standard, calcium, magnesium and lead are of higher levels than (WHO) drinking water standard. This may be due to mineralization in the study area. There is an impossibility to determine the effect of these augment on native's health, because most of them are medicated by traditional medicines.  As a final result most of drinking water in the area of study needs treatment before use .                                                                                                                                       &nbsp