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Passport: enabling accurate country-level router geolocation using inaccurate sources

When does Internet traffic cross international borders? This question has major geopolitical, legal and social implications and is surprisingly difficult to answer. A critical stumbling block is a dearth of tools that accurately map routers traversed by Internet traffic to the countries in which they are located. This paper presents Passport: a new approach for efficient, accurate country-level router geolocation and a system that implements it. Passport provides location predictions with limited active measurements, using machine learning to combine information from IP geolocation databases, router hostnames, whois records, and ping measurements. We show that Passport substantially outperforms existing techniques, and identify cases where paths traverse countries with implications for security, privacy, and performance.First author draf

Passport: Enabling Accurate Country-Level Router Geolocation using Inaccurate Sources

When does Internet traffic cross international borders? This question has major geopolitical, legal and social implications and is surprisingly difficult to answer. A critical stumbling block is a dearth of tools that accurately map routers traversed by Internet traffic to the countries in which they are located. This paper presents Passport: a new approach for efficient, accurate country-level router geolocation and a system that implements it. Passport provides location predictions with limited active measurements, using machine learning to combine information from IP geolocation databases, router hostnames, whois records, and ping measurements. We show that Passport substantially outperforms existing techniques, and identify cases where paths traverse countries with implications for security, privacy, and performance

Cytochrome P450cam (CYP101A1) mutants to study dehalogenation of endosulfan: A persistent organic pollutant, and oxidation of β-phellandrene: A monoterpene

Cytochrome P450cam (CYP101A1) from the soil bacterium Pseudomonas putida oxidizes camphor regio- and stereoselectively at the 5-position, to give 5-exo¬-hydroxycamphor. In order to alter the substrate range of P450cam, it has to be mutated. Previously, we have randomly mutated P450cam and selected seven mutants on the bicyclic polychlorinated pollutant endosulfan (ES). Endosulfan is a pesticide and is a persistent organic pollutant (POP). Endosulfan diol (ES diol), which is the major hydrolysis product of endosulfan in the environment, is also persistent in the environment, along with endosulfan itself. Here, we describe the activity of the P450cam mutants towards biodegradation of endosulfan diol. The P450cam mutants convert these substrates to substituted ortho-quinones, which we detected using 4-aminoantipyrine (4-AAP) in the assays. Here, we have studied the dehalogenation of endosulfan diol catalyzed by the endosulfan – selected P450cam mutants, using in vitro kinetics, chloride release assays and 13C labeled endosulfan diol. ES7 (V247F/D297N/K314E) was found to be the most active mutant, significantly more active than the wild type (WT) towards biodegradation of ES diol. On average ~ 5.2 Cl- ions are released per aromatic product detected upon turnover of ES diol. Based on these findings, we propose a mechanism that begins with the epoxidation of the ES-substrate’s double bond on the norbornene system, proceeds with elimination of six chloride ions and loss of the bridge as CO2, to furnish the ortho-quinone. The monoterpene β-phellandrene is released by certain species of pine when placed under stress. Due to the limited supply of β-phellandrene available from natural sources, here we describe a short synthesis of racemic β-phellandrene from readily available β-pinene. Furthermore, oxidized monoterpenes are known to be released by plants and to function as attractants or repellents of insects, so it is of interest to find ways of selectively oxidizing β-phellandrene. The compound was found to be a substrate for WT-P450cam and the ES7 mutant. In in vitro assays with the cytochrome P450cam, β-phellandrene was hydroxylated

Empirical Essays on Migration and Remittances in Pakistan

In this dissertation, we develop four essays to analyse several aspects of migration for Pakistan on the basis of household level panel and cross-sectional data from 1986 to 2007. The aspects analysed are decision to migrate domestically and internationally, financing of migration, decision to send remittances and spill-over effects on remittances. These essays are presented in Chapters four through seven. Other chapters include a general introduction, literature review and concluding remarks and policy discussions. Chapter four (essay one) studies the determinants of the two locational migrations (internal-and-international migration) using discrete choice models. The study begins by investigating migration as a whole and then looks at the more disaggregate choice. On the snapshot of migration as a whole we detect an intriguing size-composition effect on the household’s probability of migration: the larger the household, the greater the probability of migration. On the other hand, the more dependants a household has (in terms of the number of children and young females), the less likely it is to have migrant member. This relation is by and large true for both types of migration – internal or international. We also find that the probability of migration is inversely related to the pre-migration initial (as observed at the beginning of the study period) landholding of the household. For a one-acre decrease in landholding will results in 11% increase in international migration relative to never migration, and comparatively it shows a 1.3% increase in internal migration. So it is most likely that households have depleted their landholding to raise finances for their migration. Using the same dataset (of chapter four) in chapter five (essay two), we study the determinants of receiving remittances by constructing a Box-Cox double hurdle model for households. The first iii hurdle deals with the decision to receive remittance, and conditional on participation, the hurdle deals with the amount or level of remittances. The first stage regression does reveal household characteristics such as household head age, number of children aged less than 11 years, and the district level fixed effects to be important for remittances, be it for internal or international migration. From these factors, it may be concluded that household level characteristics and regional factors are the important determinants for the probability of remittances. The second hurdle deals with the determinants of remittance amounts, conditional on being a remitter. The household head education and age appear to affect the level of remittances, unlike the participation results. Comparing the impact across the participation and the level of remittances received by the household, we find that both members travelling within and outside of the country are the important determinant for both hurdles. We find that there exists opposing effect of probability to receive remittances and the level of remittances at the district level. Chapter six (essay three) studies the determinants of internal- and –international remittances by introducing the random- and –fixed effects by employing a multilevel econometric methodology to study the spread of remittances at different levels of spatial aggregation. Few studies use multilevel analyses on remittance data, but to the best of our knowledge, there is none for in the context of a developing country such as Pakistan. We use data from Pakistan Household Integrated Economic Survey of 2001-02, employing household-,village-, district-, province- and regional-level variables to understand how heterogeneities at these different levels impact on the probability of receiving (or sending) remittances, relative to other households in the same village or district. Our findings suggest that the determinants of internal remittances are different from those of international remittances. We find greater variation in the odds of receiving remittances (both internal and international) among households from same villages within the same district than those located in different villages within same district. Also with regional fixed effects, the correlation is refined and thus it becomes smaller. iv In chapter seven (essay four), we empirically study the possible multiplier effect (spill over) triggered by remittances by using the Pakistan Household Integrated Economic Survey of 2007-08. While the existing studies provide a compelling empirical evidence of remittance income is more likely to be saved and invested in land, housing, and human capital, but it is unclear to what extent it contribute to the origin community. The existing literature is unable to answer the question whether remittances causes multiplier or spill-over effect. If they do exists, then to what extent? Motivated by the concern that the remittance can generate multiplier effects in origin communities. We investigate the role of household interdependencies of the remittances by exploiting a novel method of identification based on the comparison of the variance of household behaviour at the different level of aggregation within and between a different districts of Pakistan (Graham, 2008). This method allows for identification of two problems that arise due to self-selection and unobservable heterogeneity. We quantify the social multiplier of remittances to be 1.12, suggesting sizable spill-over between eighty one districts in Pakistan. Our result suggests that social multiplier in terms of remittances has contributed to the development of rural household of Pakistan

Identification of Flux Maps at Constant Speed for Synchronous Motors

The accurate identification of flux linkages and inductances play a vital role in developing high-performance control methods for synchronous motors (SMs). In this thesis, the identification of flux maps of SMs at constant speed is done. The aim of this thesis is to achieve look-up tables of flux linkages as a function of machine currents. Simulation are performed on a 6.7-kW synchronous reluctance motor (SyRM). The current controlled SyRM, operating at constant speed, is fed with current sequences and the corresponding voltages are calculated. By using these calculated voltages, the motor flux linkages are identified and stored in the form of look-up tables. The iron losses and stator resistance variation are compensated during the identification process. Theses linkage look-up tables can be used as a benchmark for testing different saturation models of synchronous motors. From these look-up tables, the information about motor inductances can be obtained which can be used to fully exploit the motor torque and speed range by determining various control strategies such as the maximum torque per ampere (MTPA) and maximum torque per volt (MTPV)

Flood Disaster in Pakistan and its Impact on Agriculture Growth (A Review)

The main aim of this paper is to study the flood disaster in Pakistan and its impact on agriculture growth of Pakistan during the flood period of 2010-2014. Pakistan has during the last five consecutive years of 2010, 2011, 2012, 2013 and 2014 faced floods and flash floods. It has been responsible for damages to crops, seeds, households, food grains, livestock and infrastructure. In September 2014, heavy monsoon rains and floods in the catchment areas of India's eastern rivers of Jhelum, Ravi, Sutlej, and Chenab, resulted in flash floods in Punjab, Gilgit Baltistan and Azad Jammu and Kashmir (AJ&K). Over 1 million acres of cropland and 250,000 farmers were affected, in most cases resulting in the loss of standing food, fodder or cash crops. Keywords: Flood disaster, Agricultural Growth, Monsoon, Socio Economic & Infrastructur

The role of Ca2+ influx mechanisms in the regulation of human cardiac fibroblasts in 2D- and 3D- culture models

Cardiac fibrosis is a serious health problem commonly associated with cardiovascular diseases and remains an increasing health burden around the globe. The development of cardiac fibrosis involves the activation and differentiation of mainly resident cardiac fibroblasts (CF) by biochemical factors including angiotensin II (Ang II) and transforming growth factor β (TGF-β). As both factors were shown to interfere with the Ca2+ handling in CF, the role of Ca2+ influx mechanisms were studied in 2D and 3D cultures of CF. In a first step, the influence of the inhibition of the store-operated calcium entry (SOCE) and the transient receptor potential channel canonical 3 (TRPC3) by BTP2 (YM-58483) and Pyr3 (Pyrazole 3), respectively, on the Ca2+ handling were determined in 2D cultured normal human ventricular cardiac fibroblasts (NHCF-V). Both inhibitors were shown to reduce the basal and Ang II-dependent Ca2+ oscillations, as well as the Ang II-induced Ca2+ transients. Moreover, BTP2 was demonstrated to reduce the TGF-β-dependent Ca2+ transient and the ER calcium content under basal condition. Long-term treatment indicated that BTP2 and Pyr3 inhibited the proliferation of NHCF-V and induced cytotoxic effects in 2D cultured cells. An important difference between both inhibitors were identified for their effects on the pro-fibrotic gene expression. BTP2 blunted the expression of the major cardiac collagen isoform Col1a1, but Pyr3 was without effect. BTP2 also down-regulated the matricellular protein connective tissue growth factor (CTGF). Importantly, BTP2 increased the expression of important effectors of the unfolded protein response (UPR). In the next step, the NHCF-V were used to generate human engineered connective tissues (hECT). To induce cell activation a co-treatment with Ang II and TGF-β (AT) was applied. This treatment was shown to increase hECT compaction, contraction, stiffness, and strength, and to decrease extensibility. In the following, the anti-fibrotic potential of BTP2 was shown by a significant reduction of the AT-induced compaction, contraction, stiffness, and strength, and by an increase in elasticity and extensibility of the fibrotic hECT. Molecular analysis revealed that BTP2 treatment resulted in enhanced cell loss within the initial culture period and a downregulation of Col1a1. Mechanistically, BTP2 induced mild ER-stress indicated by an up-regulation of the UPR mediator DDIT3. Finally, Pyr3 also significantly reduce the AT-induced contraction and stiffness but surprisingly, none of the other biomechanical parameters. In summary, the BTP2-dependent Ca2+ influx inhibition induced ER-stress which interfered with ECM protein expression and fibrotic processes in hECT, whereas, Pyr3 interfered only with the contractile behavior of NHCF-V.2021-12-1