Migration decision-making: a geographical imaginations approach

Within the past two decades, scholars of migration are beginning to understand the importance of incorporating cultural dimensions into research concerning migration decision‐making practices. While it is recognised that economic, social and political factors are central in the formation of the desire to migrate, these factors alone are unable to explain the migratory decisions of many. However, although cultures of migration has emerged as the dominant approach for incorporating cultural facets of migration decision‐making, I suggest this approach does not offer a holistic exploration into the impacts of ‘culture’ due to its reluctance to fully engage with the importance of place. This paper outlines a geographical imaginations approach that is able to account for the complexities of culture and place on migration decision‐making, based on insights developed from interviews undertaken with Filipino nurses in the UK and in the Philippines. The approach is able to account for the impacts of culture and place on migration decision‐making in four main, interlinking ways. It is sensitive to the influence of geographical scales, to ideas of culture and place, to understandings of both home and away, and is able to account for non‐migration

Camel Milk and the Prevention of Glucose Cataract, an Organ Culture Study

Purpose: To test if camel milk affects glucose-induced opacity in organ cultured rat and human lenses.Methods: Whole human and rat lenses were cultured in various media containing either 55 mM glucose, camel milk, or a combination of both glucose and milk. Some lenses were cultured in a media containing neither moiety to establish a control. Absorbance spectra of human and rat lenses were measured daily using a visible/ultraviolet light spectrometer. Lens opacities were graded by a blinded grader from photographs taken daily. Aldose reductase activity, catalase activity, glutathione and receptor for advanced glycation end products levels were assayed.Results: The optical density and light scattering intensity of human lenses cultured with glucose were higher after two to four days in organ culture compared with lenses cultured without glucose. Camel milk in the culture media attenuated the glucose-induced increase in optical density, light scattering intensity and opacity grade after two to four days for both human and rat lenses. Aldose reductase activity, catalase activity and glutathione levels were restored but the receptor for advanced glycation end products was similar in rat lenses cultured with glucose compared with those cultured with glucose and camel milk. There were no differences between the assayed moieties in human lenses cultured with glucose or glucose plus milk. Since camel milk restored rat lens glutathione levels, it is possible that camel milk may protect the lens from oxidation and significantly reduce the glucose-induced increase in light scattering of human lenses. Structurally and physiologically, rat lenses are distinct from human lenses, therefore, the rat lens data was highly variable when compared with the human lens data, highlighting the importance of using human lenses in future studies.Conclusions: Camel milk present in the organ culture medium inhibited the glucose-induced opacity in human lenses and restored the amount of glutathione to the same levels of lenses not cultured in glucose. The positive results of the current study leads to future studies to determine the moieties in camel milk that are responsible for cataract inhibition and in vivo studies involving camel milk

Variability in the stellar initial mass function at low and high mass: 3-component IMF models

Three component models of the IMF are made to consider possible origins for the observed relative variations in the numbers of brown dwarfs, solar-to-intermediate mass stars, and high mass stars. Three distinct physical processes are noted. The characteristic mass for most star formation is identified with the thermal Jeans mass in the molecular cloud core, and this presumably leads to the middle mass range by the usual collapse and accretion processes. Pre-stellar condensations (PSCs) observed in mm-wave continuum studies presumably form at this mass. Significantly smaller self-gravitating masses require much larger pressures and may arise following dynamical processes inside these PSCs, including disk formation, tight-cluster ejection, and photoevaporation as studied elsewhere, but also gravitational collapse of shocked gas in colliding PSCs. Significantly larger stellar masses form in relatively low abundance by normal cloud processes, possibly leading to steep IMFs in low-pressure field regions, but this mass range can be significantly extended in high pressure cloud cores by gravitationally-focussed gas accretion onto PSCs and by the coalescence of PSCs. These models suggest that the observed variations in brown dwarf, solar-to-intermediate mass, and high mass populations are the result of dynamical effects that depend on environmental density and velocity dispersion. They accommodate observations ranging from shallow IMFs in cluster cores to Salpeter IMFs in average clusters and whole galaxies to steep and even steeper IMFs in field and remote field regions. They also suggest how the top-heavy IMFs in some starburst clusters may originate and they explain bottom-heavy IMFs in low surface brightness galaxies.Comment: 10 pages, 2 figures, accepted by Monthly Notices of the Royal Astronomical Societ

An iterative algorithm for parametrization of shortest length shift registers over finite rings

The construction of shortest feedback shift registers for a finite sequence S_1,...,S_N is considered over the finite ring Z_{p^r}. A novel algorithm is presented that yields a parametrization of all shortest feedback shift registers for the sequence of numbers S_1,...,S_N, thus solving an open problem in the literature. The algorithm iteratively processes each number, starting with S_1, and constructs at each step a particular type of minimal Gr\"obner basis. The construction involves a simple update rule at each step which leads to computational efficiency. It is shown that the algorithm simultaneously computes a similar parametrization for the reciprocal sequence S_N,...,S_1.Comment: Submitte

IKK phosphorylates Huntingtin and targets it for degradation by the proteasome and lysosome

Expansion of the polyglutamine repeat within the protein Huntingtin (Htt) causes Huntington's disease, a neurodegenerative disease associated with aging and the accumulation of mutant Htt in diseased neurons. Understanding the mechanisms that influence Htt cellular degradation may target treatments designed to activate mutant Htt clearance pathways. We find that Htt is phosphorylated by the inflammatory kinase IKK, enhancing its normal clearance by the proteasome and lysosome. Phosphorylation of Htt regulates additional post-translational modifications, including Htt ubiquitination, SUMOylation, and acetylation, and increases Htt nuclear localization, cleavage, and clearance mediated by lysosomal-associated membrane protein 2A and Hsc70. We propose that IKK activates mutant Htt clearance until an age-related loss of proteasome/lysosome function promotes accumulation of toxic post-translationally modified mutant Htt. Thus, IKK activation may modulate mutant Htt neurotoxicity depending on the cell's ability to degrade the modified species

Between Qasbas and Cities: Language Shifts and Literary Continuities in North India in the Long Eighteenth Century

The cultural memory of Awadh is almost exclusively identified with Urdu poetry and courtesan culture, and already in the colonial period it came to stand as the epitome of the “last phase of Oriental culture” (‘Abdul Halim Sharar). But if instead of taking a retrospective, nostalgic view we approach literary culture in Awadh prospectively and multilingually and broaden our lens to consider not just the capitals, Faizabad and Lucknow, but also the qasbas (small towns), the small rural courts, the nearby growing city of Banaras, and the colonial capital of Calcutta, a different set of literary dynamics and shifts comes into view. The prevalent image of Awadh as identified with Urdu and Lucknow is not wrong, of course, but it does obscure the other stories, trajectories, and languages. This essay considers some of them. A multilingual and prospective approach helps us consider the circulation of literary tastes across the colonial divide and recognize the production of forgetfulness and ignorance that accompanied modern narratives of languages and literary histories, both colonial and Indian, and that made a host of texts “homeless” (Mohamad Tavakoli-Targhi)

Transnational activities and aspirations of irregular migrants in Belgium and the Netherlands

The literature on immigrant transnationalism and on irregular immigration suggests irregular migrants engage relatively little in transnational activities because of the obstacles associated with their legal and economic statuses. Drawing on participant observation and in-depth interviews with a diverse population of irregular migrants in Belgium and the Netherlands, however, I shall demonstrate in this article that irregular migrants do indeed engage in various transnational activities. Moreover, I argue that a focus on aspirations helps to understand why irregular migrants either do or do not engage in specific transnational activities. Distinguishing between investment, settlement and legalization aspirations, I analyse whether and for what reasons irregular migrants carry out economic, social and political transnational activities. I conclude that future research on transnationalism and on the incorporation of irregular and regular migrants alike could benefit from contextualizing the agency of migrants by taking their aspirations into account

Cosmology at Low Frequencies: The 21 cm Transition and the High-Redshift Universe

Observations of the high-redshift Universe with the 21 cm hyperfine line of neutral hydrogen promise to open an entirely new window onto the early phases of cosmic structure formation. Here we review the physics of the 21 cm transition, focusing on processes relevant at high redshifts, and describe the insights to be gained from such observations. These include measuring the matter power spectrum at z~50, observing the formation of the cosmic web and the first luminous sources, and mapping the reionization of the intergalactic medium. The epoch of reionization is of particular interest, because large HII regions will seed substantial fluctuations in the 21 cm background. We also discuss the experimental challenges involved in detecting this signal, with an emphasis on the Galactic and extragalactic foregrounds. These increase rapidly toward low frequencies and are especially severe for the highest redshift applications. Assuming that these difficulties can be overcome, the redshifted 21 cm line will offer unique insight into the high-redshift Universe, complementing other probes but providing the only direct, three-dimensional view of structure formation from z~200 to z~6.Comment: extended review accepted by Physics Reports, 207 pages, 44 figures (some low resolution); version with high resolution figures available at http://pantheon.yale.edu/~srf28/21cm/index.htm; minor changes to match published versio

Direct Search for Dark Matter - Striking the Balance - and the Future

Weakly Interacting Massive Particles (WIMPs) are among the main candidates for the relic dark matter (DM). The idea of the direct DM detection relies on elastic spin-dependent (SD) and spin-independent (SI) interaction of WIMPs with target nuclei. In this review paper the relevant formulae for WIMP event rate calculations are collected. For estimations of the WIMP-proton and WIMP-neutron SD and SI cross sections the effective low-energy minimal supersymmetric standard model is used. The traditional one-coupling-dominance approach for evaluation of the exclusion curves is described. Further, the mixed spin-scalar coupling approach is discussed. It is demonstrated, taking the high-spin Ge-73 dark matter experiment HDMS as an example, how one can drastically improve the sensitivity of the exclusion curves within the mixed spin-scalar coupling approach, as well as due to a new procedure of background subtraction from the measured spectrum. A general discussion on the information obtained from exclusion curves is given. The necessity of clear WIMP direct detection signatures for a solution of the dark matter problem, is pointed out.Comment: LaTeX, 49 pages, 14 figures, 185 reference