4,743 research outputs found
Formal security analysis of registration protocols for interactive systems: a methodology and a case of study
In this work we present and formally analyze CHAT-SRP (CHAos based
Tickets-Secure Registration Protocol), a protocol to provide interactive and
collaborative platforms with a cryptographically robust solution to classical
security issues. Namely, we focus on the secrecy and authenticity properties
while keeping a high usability. In this sense, users are forced to blindly
trust the system administrators and developers. Moreover, as far as we know,
the use of formal methodologies for the verification of security properties of
communication protocols isn't yet a common practice. We propose here a
methodology to fill this gap, i.e., to analyse both the security of the
proposed protocol and the pertinence of the underlying premises. In this
concern, we propose the definition and formal evaluation of a protocol for the
distribution of digital identities. Once distributed, these identities can be
used to verify integrity and source of information. We base our security
analysis on tools for automatic verification of security protocols widely
accepted by the scientific community, and on the principles they are based
upon. In addition, it is assumed perfect cryptographic primitives in order to
focus the analysis on the exchange of protocol messages. The main property of
our protocol is the incorporation of tickets, created using digests of chaos
based nonces (numbers used only once) and users' personal data. Combined with a
multichannel authentication scheme with some previous knowledge, these tickets
provide security during the whole protocol by univocally linking each
registering user with a single request. [..]Comment: 32 pages, 7 figures, 8 listings, 1 tabl
The Synthesis and Enzymatic Characterization of 6-Amino-FMN with BluB; The Last Unsolved Biosynthetic Module of Vitamin B12
The last unsolved module for the biosynthetic pathway of vitamin B12 is the biosynthesis of the
lower axial ligand, dimethylbenzimidazole (DMB). Recently, the oxygen-dependent enzyme,
BluB, has been shown to catalyze the oxidative fragmentation of coenzyme B2, FMN, and
produces dimethylbenzimidazole (DMB), erythrose-4-phosphate, and alloxan. BluB is the first
enzyme shown to utilize FMN as a substrate rather than as a coenzyme. Our goal is to elucidate
the mechanism by which BluB catalyzes the oxidative fragmentation of FMN with molecular
oxygen. Previous studies, done by our group, with numerous substrate analogues have shown no
enzymatic activity with BluB and conclude that the active site of BluB is highly selective for the
native substrate. In this study, the synthesis of 6-amino-FMN and its activity with BluB are
described. LCMS analysis of the enzymatic assays confirmed the production of 4-amino-DMB.
This discovery suggests that active site of BluB tolerates substrate analogues with substituents at
the 6-position and additional 6-substituted substrate analogues can be designed to provide
mechanistic insight
The Importance of National Identity in Social Studies Classes in Puerto Rico: An Examination of Teacher and Student Perceptions of “Lo Nacional”
The Commonwealth of Puerto Rico, an unincorporated territory of the United States, is home to approximately 3.4 million U.S. citizens. The literature on Puerto Rican national identity (PRNI) describes how and why it has been debated on the island for more than five hundred years throughout the colonial trajectory, once under Spain and now as a commonwealth of the United States.
The education system in Puerto Rico, and particularly the social studies curriculum, has been used to promote particular ideologies regarding national identity. This study identifies what middle school teachers teach about PRNI and how seventh grade students identify themselves in terms of national identity. The investigation of curriculum delivery examines the elements that foster the Puerto Rican national character. Social studies educators who neglect the multiplicity of Puerto Rican identities fail to acknowledge that educational practices should be inclusive of the diverse understandings of PRNI. Such an acknowledgement needs to be incorporated to social studies classes where teachers discuss Puerto Rico’s relationship with the United States. Examining social studies classes in Puerto Rico becomes the ideal context to develop conjectures about PRNI that include a transnational identity beyond the nation-state paradigms.
Using a mixed method approach with a concurrent embedded strategy, I identified student perceptions about PRNI, which differ from those of educators. Teachers’ perceptions, citizenship, ethnic identity, and political ideology become intertwined with the delivery of social studies classes. Nevertheless, students develop their own perceptions of PRNI with only minor reference to the social studies class.
Students express dissatisfaction with their social studies classes. They also assign a high level of importance to PRNI, express a strong feeling of belonging to the Puerto Rican nation, and describe markers of national identity. The previous categories become pivotal considerations for the assessment of content-rich social studies lessons
Multidimensional poverty in the EU: rethinking AROPE through a multi-criteria analysis
At risk of poverty or social exclusion rate (AROPE) constitutes the pivotal indicator of living conditions and poverty in the European Union. Nevertheless, as a multidimensional poverty measure, it has some drawbacks that significantly reduce its utility. In this paper, we propose an alternative multi-criteria approach that provides some innovations for the computation of multidimensional poverty in the European countries. We first propose a normalization formula for each dimension by using a double point of reference. We then put forward alternative aggregation functions that permit diverse degrees of substitutability across dimensions. This new formulation allows us to go beyond focusing merely on the rate of people classified as AROPE, making it possible to evaluate aspects such as the intensity of multidimensional poverty and how changes over time are distributed across population in terms of shared prosperity, as showed in an illustration for the EU28 countries.Universidad de Málaga. Campus de Excelencia Internacional AndalucĂa Tec
I’m Here for a Reason: Motivational Factors of First-Generation Latino Males to Attend College
This intrinsic case study explored the motivational factors to attend college of firstgeneration Latino males enrolled at a mid-sized institution in the Mid-Atlantic using Self- Determination Theory of motivation (Deci & Ryan, 1985, 2000) as a theoretical lens. Data included individual interviews and focus group interviews with 15 participants as well as a review of Web pages and University materials. Data analysis resulted in ten themes with extrinsic and intrinsic motivational factors in congruence with Deci and Ryan’s (1985) Self- Determination Theory of motivation. Findings also revealed barriers hindering these participants from pursuing college. Implications suggest the importance of administrators, teachers, family, and friends involved to inspire, encourage, and support first-generation Latino males as they work to succeed in college
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