103 research outputs found
Critical ICT4D:The Need for a Paradigm Change
Get PDFICT for Development (ICT4D) research has evolved significantly in the course of its history. Originally characterized by a technology-transfer vision, positing technology as intrinsically “good” and desirable for development, it subsequently entered a phase of problematization of the very notion of “development”, as well as the ability of ICTs to contribute to it. Against this backdrop, we highlight the need for a paradigm change that sees Critical ICT4D – a vision that constructively problematizes the core assumptions of ICT4D research – at the core of theorizing, designing and executing research on ICTs for development. With the idea of Critical ICT4D, we introduce a way of thinking that takes stock of the adverse effects of ICTs on its intended beneficiaries, at the same time developing routes to imagining and building fairer technologies in contexts of structural vulnerability.</p
Understanding Parental Perceptions of Children’s Online Use in Australian Aboriginal Communities by Adapting Traditional Indigenous Practices
No full textThe rapid proliferation of digital media has significantly changed how children interact with the online world. However, within Australian Aboriginal communities, the impact of these technologies on children’s well-being and cultural identity remains relatively unexplored. This study aims to understand parental perceptions regarding children’s online use within these communities. Indigenous research methodologies emphasize community engagement, cultural protocols and reciprocal relationships between researchers and participants. By integrating these approaches into the study design, a comprehensive understanding of the complexities surrounding children’s online use can be achieved while respecting the unique perspectives and voices of Aboriginal parents. This research in progress employs a qualitative approach, incorporating participatory action design research and yarning circles as key methods. Yarning circles are traditional Indigenous storytelling and knowledge-sharing forums that encourage open dialogue and collective decision-making. The data collected from the yarning circles will be analyzed thematically, identifying common themes, perspectives and concerns emerging from the discussions. The findings will shed light on parental perceptions of children’s online use, which will be utilized in an appropriate intervention to bridge parents’ and caregivers’ knowledge gaps
Identity Platforms and Anti-LGBTQ+ Legislation::Implications for Safeguarding Personal Data
No full textLittle is known about how digital identity platforms can be managed and operated in countries where governments have introduced anti-LGBTQ+ legislation. This work-in-progress study explores the tensions associated with digital identity platforms in these contexts. It draws on concepts from actor network theory to analyze field data collected by the authors in the Health Information Systems (HISP) research programme around a digital platform (DHIS2) that is installed in 114 countries globally, primarily in the health sector. The study identifies contradictory interests among the human and non-human actors, and analyzes these according to (1) the operation of a digital identity platform in a legally gray area, (2) visibility and invisibilization of vulnerable populations, and (3) human rights vs neo-colonialism. In particular, the paper identifies the potential for enrollment of the identity platform technology from intended into realities of use in identifying LGBTQ+ individuals and groups, identifying risks of data-induced harm and routes to overcoming them.<br/
Studies On 2,3-Unsaturated Sugars : Reactivity Switching, Rearrangements And Conjugate Additions
Get PDFUnsaturated sugars constitute as an important category of carbohydrate precursors in synthesis. Specifically, 1,2- and 2,3-unsaturated glycosides are excellent intermediates to derivatize monosaccharides and as building blocks in organic synthesis. For example, a major utility of 1,2-unsaturated sugars, namely glycals, is the addition reactions to afford 2-deoxy glycosides under acidic conditions and rearrangement reactions to produce 2,3-unsaturated glycosides. Lewis acids favour the formation of 2,3-unsaturated glycosides, whereas, Brønsted acids lead to normal addition products. A mixture of both the product is obtained often, depending on the nucleophiles and the stereochemistry of glycal. Chapter 1 of the thesis describes (i) reactivities of glycals under acidic condition and (ii) a general survey of reactions involving on C2-C3 carbons of monosaccharides.
Glycals are useful precursors to derive a number of functionalized monosaccharide derivatives. A well-known acid catalyzed reaction of glycals is their conversion to 2,3¬unsaturated glycosides, known as the Ferrier products. In a research programme, reactivity switching and selective activation of C-1 or C-3 of 2,3-unsaturated thioglycosides under acid catalyzed condition was undertaken. Thioglycosides are excellent glycosyl donors and can be activated easily. In identifying the reactivities of 2,3-unsaturated thioglycosides, obtained through Ce(IV)-mediated reaction of a glycal, it was intended to study the glycosylation reaction and also the reactivity control of C1-C3 carbons during a glycosylation reaction. Experiments showed that a reactivity switching was possible through activation of either C-1 or C-3. Thus, C-1 glycosylation with alcohol acceptors occurred in the presence of NIS/TfOH, without the acceptors reacting at C-3. On the other hand, reaction of 2,3-unsaturated thioglycosides with alcohols mediated by triflic acid alone led to a transposition of C-1 ethylthio-moiety to C-3 intramolecularly, to form 3-ethylthio-glycals. Resulting glycals underwent glycosylation with alcohols to afford 3-ethylthio-2-deoxy glycosides. However, when thiol was used as an acceptor, only a stereoselective addition at C-3 resulted, so as to form C-1, C-3 dithio-substituted 2-deoxypyranosides. Oxocarbenium ion is the reactive intermediate during activation of a glycosyl donor, and in the case of a 2,3-unsaturated thioglycosides, the oxocarbenium ion may stabilize further by the presence of a C2-C3 unsaturation. Reaction of a nucleophile with allylic oxocarbenium ion may lead to two regio-isomers. Initially, NIS/TfOH was attempted on 2,3–unsaturated sugar with various alcohols and it was found that C-1 was the preferred reactive centre (Scheme 1)
Scheme 1
In order to optimize the reaction for selective nucleophilic attack at C-3, further study was continued by using stoichiometric TfOH, in presence of acceptors alcohols with the intension to activate the double bond. The reaction led to the formation of 2-deoxy O-glycosides with the concomitant transposition of C-1 ethylthio-moiety to C-3 (Scheme 2).
Scheme 2
An important observation was that the transposition of thioethyl group from C-1 to C-3 was highly regioselective. For example, with thiocresol as the nucleophile, there was an addition across the C-2-C-3 double bond to afford C-1, C-3-dithio derivative (Scheme 2). Thus, hard-soft nature of the nucleophiles, as well as, carbon centres helped to rationalize the reactivites.
It was also observed that the intramolecular transposition of thioethyl group is highly stereo-controlled by equatorial C-4 acetoxy group. Thus, thioethyl nucleophile approached selectively at C-3 and afforded trans-diequatorial products. This rationalization was further confirmed through (i) reaction of benzyl protected 2,3-unsaturated thioglycoside, wherein a C-3 epimeric mixture was observed in 1:1 ratio; (ii) galactosyl derivative under similar reaction condition afforded anomeric mixture of 3-(4-methylphenylthio)-O-glycosides, with trans-diaxial orientation of substituent at C-3 (Scheme 3).
Scheme 3
These reactions confirmed the role of C-4 substituent on the carbocation at C-3, through the presence or absence of a neighbouring group participation. In summary, in Chapter 2 the selective activation of either anomeric carbon or C-3 with proper choice of activation and reactivity control at each carbon will be described.
Thioglycosides are excellent glyosyl donor and their glycosylation reactions were well explored. Upon indentifying the intramolecular transposition of thioalkyl/aryl functionality from C-1 to C-3, further investigations was undertaken to utilize the newly formed carbon sulfur bonds at C-3. Realizing a potential for such 3-alkyl/aryl thio 2-deoxy sugar, the Pummerer rearrangement was investigated. For this purpose, the thioalkyl/aryl moiety at C-3 was oxidized first to a sulfoxide. The resulting sulfoxide was allowed to undergo Pummerer rearrangement to afford vinyl sulfide (Scheme 4), resulting from the elimination of HOAc in the thioacetal formed in situ. Having implemented Pummerer rearrangement on a sugar substrate, synthetic utility of the rearrangement product, namely vinyl sulfide was undertaken.
An effort to implement conjugate addition reaction was undertaken, which required the conversion of vinyl sulfide to vinyl sulfoxide in the first step. The conjugate addition reactions were first conducted with alkoxide nucleophiles. The reaction showed that addition of nucleophiles occurred from axial face to furnish manno-configured derivatives as a single diastereomer at sulfinyl sulfur in a moderate yield along with O-deacetylated product. It was also found that O-benzyl protected sugar vinyl sulfoxide was totally resistant to the conjugate addition reaction (Scheme 4).
Scheme 4
In order to find the influence of the substituents in sulfoxide moiety in the addition of nucleophiles, additional study was conducted in which a less hindered thioethyl moiety was installed in place of p-tolylthio moiety. To install ethylthio moiety, a similar sequence of reaction was undertaken as described previously in Scheme 4. Conjugate addition reaction with alkoxide nucleophiles was conducted and analysis of the reaction showed that the addition of alkoxides remained similar, leading to the formation of manno-configuration of substituents (Scheme 5).
Scheme 5
The configuration of the Michael adducts were ascertained from 1H NMR, as well as 2D NMR spectroscopies. H-1 of all adducts appeared as an apparent singlet, consistent with very small J1,2 values. Aryl vinyl sulfoxide afforded conjugate addition product at much higher ratio than corresponding alkyl vinyl sulfoxide. Thus, among aryl and alkyl vinyl sulfoxides, conjugate addition occurred better with the aryl vinyl sulfoxide, indicating a strong electronic effect of aryl group in stabilizing the conjugate anion which would form in situ during nucleophilic addition with vinyl sulfoxide. Therefore, p-tolylthio substituted vinyl sulfoxide served as a more efficient Michael acceptor when compared to the thioethyl substituted vinyl sulfoxide.
Asymmetric environment of vinyl sulfoxides play a vital role during the reaction. Vinyl sulfoxides can exist in two stereochemically distinct conformation which makes the vinyl group electronically dissimilar. In one of the conformer S-O and C-C bonds are coplanar, whereas in the other conformation, these two bonds are opposite to each other. It is agreed generally that vinyl sulfoxides generally try to adopt the most reactive conformer during the reaction in which the C-C and S-O bonds are syn to each other. Thus, the preference for an axial attack would originate from a face anti to the lone pair of electrons on the sulfur of sulfoxide functionality, leading to the formation of the product with manno-configuration. As O-deacetylated vinyl sulfoxide was obtained along with the Michael adducts, it was assumed that one of the epimers of vinyl sulfoxide appeared to be more reactive when compared to the other. Chapter 3 describes implementation of a Pummerer rearrangement in order to synthesize a sugar vinyl sulfoxide and its conjugate addition reactions with alkoxide nucleophiles.
The nucleophilic addition reactions of vinyl sulfoxide with other nucleophiles were studied further. The effect of the substituents of chiral sulfoxides in conjugate addition reactions was also incorporated in the course of reactions. Reactions of amines, carbon and sulfur nucleophiles were undertaken with p-tolylthio-substituted vinyl sulfoxides. The reactions showed formation of the addition-elimination products (Scheme 6). All primary amines, carbon and sulfur nucleophiles afforded C-2 axial epimer, namely, threo-epimer exclusively, wherein secondary amines furnished the equatorial vs axial epimer in 3:1 ratio.
Scheme 6
In order to assess the course of the reaction, vinyl sulfoxide presenting a p-cumenethio¬moiety was installed in place of p-tolylthio moiety. Conjugate addition reactions were performed with both primary as well as secondary amines that showed formation of the C-2 epimeric mixtures. With both the primary and secondary amines C-2 equatorial epimer was found to be as the major product (Scheme 7).
Scheme 7
In conjugate addition of vinyl sulfoxides, nucleophiles approach the olefinic face preferentially, which is anti to the electron rich sulfur lone pair of electrons and syn to the bulky aryl group. Therefore, C-2 axial epimer was observed as most favourable product. However, secondary amines remarkably influenced the pattern as well as selectivity of the reaction. Steric considerations were likely to dictate the overall reactivity with secondary amines which was even more pronounced when using p-cumenethio-substituted vinyl sulfoxide. Chapter 4 describes the conjugate additions as well as remote effect of aryl substituent on the selectivity of addition of amines on sugar sulfoxide
In summary, the Thesis establishes:
A new reactivity of switching and a selective activation of 2,3-unsaturated thioglycoside; A Pummerer rearrangement route in order to synthesize sugar vinyl sulfide for the first time, which on selective oxidation furnish a sugar vinyl sulfoxide, a useful precursor for conjugate addition reactions; An assessment of the stereoelectronic, as well as, steric effect of the chiral vinyl sulfoxide with various nucleophiles in conjugate addition reactions; Influence of the protecting groups were also studied in conjugate addition reactions.
Overall the study presented in the Thesis provides a new insight to unsaturated sugars. The salient features of the present findings also showed that the intermediates such as C-3 substituted thioalkyl/aryl glycosides, vinyl sulfides, a variety of new C-2 substituted vinyl sulfoxides are also the potential sites for many types of modifications in monosaccharides.
(For structural formula pl see the pdf file
Reactivity switching and selective activation of C-1 or C-3 in 2,3-unsaturated thioglycosides
No full textReactivity switching and selective activation of C-1 or C-3 in 2,3-unsaturated thioglycosides, namely, 2,3-dideoxy-1-thio-D-hex-2-enopyranosides are reported. The reactivity switching allowed activation of either C-1 or C-3, with the use of either N-iodosuccinimide (NIS)/triflic acid (TfOH) or TfOH alone. C-1 glycosylation with alcohol acceptors occurred in the presence of NIS/TfOH, without the acceptors reacting at C-3. On the other hand, reaction of 2,3-unsaturated thioglycosides with alcohols mediated by triflic acid led to transposition of C-1 ethylthio-moiety to C-3 intramolecularly, to form 3-ethylthio-glycals. Resulting glycals underwent glycosylation with alcohols to afford 3-ethylthio-2-deoxy glycosides. However, when thiol was used as an acceptor, only a stereoselective addition at C-3 resulted, so as to form C-1, C-3 dithio-substituted 2-deoxypyranosides. (C) 2011 Elsevier Ltd. All rights reserved
ICT Enabled Peace Network: Case Study of Conflict Early Warning System in Kenya
No full textPart 1: Communities, ICT-Enabled Networks, and DevelopmentInternational audienceBuilding peace in post-conflict societies is a contemporary and urgent humanitarian challenge facing the world. ICTs can potentially play a role in this process, but how and why this can be done has not attracted adequate research attention, especially in the ICT4D domain which should naturally be at the forefront of such efforts. Drawing upon Castells’ notion of counter-networks, this paper based on an empirical analysis of peace-building efforts in North-West Kenya, examines the role of ICTs in enabling effectively information flows to strengthen the efforts in building a “peace network.” Important lessons are discerned on how such counter networks can be cultivated, and some reflections are presented on how these lessons may or not be applied to other conflict-ridden areas
Sinking Under Its Own Weight: Case of Aadhaar Mediated Entitlements in India
No full textPart 2: Digital Platforms for DevelopmentInternational audienceIn this paper, we analyse through a largely conceptual analysis the application of the Aadhaar biometrics identification system in India, now assuming complex proportions, and how that facilitates or not citizen’s entitlement of welfare benefits. The conceptual analysis is informed by the works of James Scott’s Seeing like a State which cautions against such large scale state sponsored schemes ending up as disasters. Amartya Sen’s analysis of famines informs how it is important to focus on the access to the entitlement rather than the entitlement itself, which, potentially can lead to entitlement failures. The conceptual analysis developed helps to critically analyse two case vignettes related to two welfare programmes of the midday meals and the public distribution system. The paper concludes by arguing for the need to critically discussing how Aadhaar can be made to work in practice while supporting broader development objectives, rather than arguing whether Aadhaar is inherently good or bad
Self-Reinforcing Linkages Between Value and Local Ownership: Rethinking Sustainability of ICT4D Project
No full textPart 11: Sustainability in ICT4DInternational audienceThe paper addresses the wicked problem of unsustainable health information systems in the context of low and middle income countries (LMICs), specifically using a case study from India in the public health sector. The paper makes the argument that current analysis of sustainability tends to be largely “supply-driven” focusing on the provision of external resources and technical assistance needed to sustain a project. But since these external injections are self-multiplying, requiring more and more over time, they tend to not lead to satisfactory and sustainable solutions. The paper argues for a more “demand-driven” approach, where the focus is on the user and the use context. Taken from this perspective, the paper identifies two sets of processes – evolving local ownership and enhancing use – as being key to establish sustainability. Further, these processes are seen to be mutually self-reinforcing, and supported by an enabling context of use
Facial selectivities in the nucleophilic additions of 2,3-unsaturated 3-arylsulfinyl pyranosides
No full text2,3-Unsaturated 3-arylsulfinyl pyranosides undergo nucleophilic additions at C-2, with facial selectivities depending on the nucleophile and the substituent on sulfinyl sulfur. The reactions of such sugar vinyl sulfoxides lead to the addition of nucleophile preferring an axial orientation at C-2, with concomitant formation of an allylic bond at C-3 to C-4. This trend in the addition pattern is observed for primary amine, carbon and sulfur nucleophiles, whereas secondary amines prefer an equatorial addition at C-2. The effect of p-tolylthio-versus (p-isopropylphenyl)thio vinyl sulfoxide is that the equatorial nucleophilic addition is preferred even more with the latter vinyl sulfoxide. (C) 2013 Published by Elsevier Ltd
Introduction
Get PDFThe city as a mosaic of anarchic diversity and messy contradictions has always been a rich source of inspiration for practitioners of creative arts. Writers, painters, planners, photographers, performers have deemed the city as the loci of their desire, conflict, passion and memory to chart the minutes of quotidian life in various intricate forms and configurations. “The city came into being when a surplus of food allowed a diversity of tasks”, Lehan asserts in his introduction to The City in Literature. “Diversity is a key to urban beginnings and continuities, and diversity is also the snake in the urban garden, challenging systems of order and encouraging disorder and chaos” (8). As an eclectic site of cultural friction and contamination that simultaneously oscillates between polarities of belonging and non-belonging, order and chaos, the city unlocks myriad windows to the chroniclers of urban realities. The cities in their perpetual making and dismantling, bear an impression of what Amit Chaudhuri terms in a recent talk as the “unfinished-ness” in the context of modern cities1. The “unfinished” is a slippery term as Chaudhuri explains, while it may suggest the Modernist artists’ proclivity towards dereliction, ruin or fragmentation in metropolitan landscape, it also speaks of the “half-made”2, the backward, or the liminal spaces within an urban conurbation. However, this “unfinished-ness” or the fact that “cities are not finished products” as Chaudhuri posits, is also indicative of their “radical openness” and their inexhaustible potentials for reinventing themselves
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