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Relations among notions of complete non-malleability : indistinguishability characterisation and efficient construction without random oracles

Barbosa, Manuel Bernardo; Farshim, P.
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica
Publicado em //2010 ENG
Relevância na Pesquisa
37.52%
We study relations among various notions of complete non-malleability, where an adversary can tamper with both ciphertexts and public-keys, and ciphertext indistinguishability. We follow the pattern of relations previously established for standard non-malleability. To this end, we propose a more convenient and conceptually simpler indistinguishability-based security model to analyse completely non-malleable schemes. Our model is based on strong decryption oracles, which provide decryptions under arbitrarily chosen public keys. We give the first precise definition of a strong decryption oracle, pointing out the subtleties in different approaches that can be taken. We construct the first efficient scheme, which is fully secure against strong chosen-ciphertext attacks, and therefore completely non-malleable, without random oracles.

Experience-induced Malleability in Neural Encoding of Pitch, Timbre, and Timing: Implications for Language and Music

Kraus, Nina; Skoe, Erika; Parbery-Clark, Alexandra; Ashley, Richard
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /07/2009 EN
Relevância na Pesquisa
27.04%
Speech and music are highly complex signals that have many shared acoustic features. Pitch, Timbre, and Timing can be used as overarching perceptual categories for describing these shared properties. The acoustic cues contributing to these percepts also have distinct subcortical representations which can be selectively enhanced or degraded in different populations. Musically trained subjects are found to have enhanced subcortical representations of pitch, timbre, and timing. The effects of musical experience on subcortical auditory processing are pervasive and extend beyond music to the domains of language and emotion. The sensory malleability of the neural encoding of pitch, timbre, and timing can be affected by lifelong experience and short-term training. This conceptual framework and supporting data can be applied to consider sensory learning of speech and music through a hearing aid or cochlear implant.

Malleability of Attitudes or Malleability of the IAT?

Han, H. Anna; Czellar, Sandor; Olson, Michael A.; Fazio, Russell H.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 01/03/2010 EN
Relevância na Pesquisa
27.52%
In the current set of experiments, we establish, and explore the consequences of, the imprecision that characterizes the attribute response labels typically employed in the Implicit Association Test (IAT). In Experiment 1, we demonstrate the malleability of the IAT, as conventionally implemented. IAT scores are shown to be influenced by perspective mindsets induced by an unrelated preceding task. Then, we explore how the malleability of the IAT can lead to the inference that attitude change has occurred even when there is very good reason to believe it has not (Experiment 2), and conversely, how it can obscure the detection of attitude change when such change is indeed likely to have occurred (Experiment 3). We provide conceptual explanations for these discrepancies and suggest methodological improvements to enhance the specificity of IAT measures.

The Malleability of Injunctive Norms Among College Students

Prince, Mark A.; Carey, Kate B.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
27.04%
Alcohol use among college students has been associated with injunctive norms, which refer to the perceived acceptability of excessive drinking, and descriptive norms, which refer to perceptions of actual drinking. The purpose of this study was to examine the effect of a brief injunctive norms manipulation on both injunctive and descriptive norms about drinking alcohol and to explore differences in the malleability of norms across referent groups, sex, and gender role. Participants were 265 undergraduates (43% male, 70% freshmen) who completed a web-based survey for course credit. A randomly selected half were exposed to a page of information-based feedback about typical student injunctive norms. Relative to the control condition, the manipulation produced lower injunctive and descriptive norms related to typical students’ drinking but no change in either type of norm related to close friends. Femininity was associated with less permissive normative beliefs about the acceptability of excessive drinking whereas masculinity was associated with elevated perceptions of peer drinking, but neither sex nor gender role moderated the manipulation effect. We conclude that perceptions of peer approval of drinking are malleable with a very brief information-based manipulation.

The Malleability of Age-Related Positive Gaze Preferences: Training to Change Gaze and Mood

Isaacowitz, Derek M.; Choi, YoonSun
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /02/2011 EN
Relevância na Pesquisa
27.04%
Older adults show positive gaze preferences, but to what extent are these preferences malleable? Examining the plasticity of age-related gaze preferences may provide a window into their origins. We therefore designed an attentional training procedure to assess the degree to which we could shift gaze and gaze-related mood in both younger and older adults. Participants completed either a positive or negative dot-probe training. Before and after the attentional training, we obtained measures of fixations to negatively-valenced images along with concurrent mood ratings. We found differential malleability of gaze and mood by age: for young adults, negative training resulted in fewer post-training fixations to the most negative areas of the images, whereas positive training appeared more successful in changing older adults’ fixation patterns. Young adults did not differ in their moods as a function of training, whereas older adults in the train negative group had the worst moods after training. Implications for the etiology of age-related positive gaze preferences are considered.

Emergence of airway smooth muscle functions related to structural malleability

Seow, Chun Y.; Fredberg, Jeffrey J.
Fonte: American Physiological Society Publicador: American Physiological Society
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
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The function of a complex system such as a smooth muscle cell is the result of the active interaction among molecules and molecular aggregates. Emergent macroscopic manifestations of these molecular interactions, such as the length-force relationship and its associated length adaptation, are well documented, but the molecular constituents and organization that give rise to these emergent muscle behaviors remain largely unknown. In this minireview, we describe emergent properties of airway smooth muscle that seem to have originated from inherent fragility of the cellular structures, which has been increasingly recognized as a unique and important smooth muscle attribute. We also describe molecular interactions (based on direct and indirect evidence) that may confer malleability on fragile structural elements that in turn may allow the muscle to adapt to large and frequent changes in cell dimensions. Understanding how smooth muscle works may hinge on how well we can relate molecular events to its emergent macroscopic functions.

Malleability of folding intermediates in the homeodomain superfamily

Banachewicz, Wiktor; Religa, Tomasz L.; Schaeffer, R. D.; Daggett, Valerie; Fersht, Alan R.
Fonte: National Academy of Sciences Publicador: National Academy of Sciences
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
27.04%
Members of the homeodomain superfamily are three-helix bundle proteins whose second and third helices form a helix-turn-helix motif (HTH). Their folding mechanism slides from the ultrafast, three-state framework mechanism for the engrailed homeodomain (EnHD), in which the HTH motif is independently stable, to an apparent two-state nucleation-condensation model for family members with an unstable HTH motif. The folding intermediate of EnHD has nearly native HTH structure, but it is not docked with helix1. The determinant of whether two- or three-state folding was hypothesized to be the stability of the HTH substructure. Here, we describe a detailed Φ-value analysis of the folding of the Pit1 homeodomain, which has similar ultrafast kinetics to that of EnHD. Formation of helix1 was strongly coupled with formation of HTH, which was initially surprising because they are uncoupled in the EnHD folding intermediate. However, we found a key difference between Pit1 and EnHD: The isolated peptide corresponding to the HTH motif in Pit1 was not folded in the absence of H1. Independent molecular dynamics simulations of Pit1 unfolding found an intermediate with H1 misfolded onto the HTH motif. The Pit1 folding pathway is the connection between that of EnHD and the slower folding homeodomains and provides a link in the transition of mechanisms from two- to three-state folding in this superfamily. The malleability of folding intermediates can lead to unstable substructures being stabilized by a variety of nonnative interactions...

Malleability of the approximate number system: effects of feedback and training

DeWind, Nicholas K.; Brannon, Elizabeth M.
Fonte: Frontiers Research Foundation Publicador: Frontiers Research Foundation
Tipo: Artigo de Revista Científica
Publicado em 19/04/2012 EN
Relevância na Pesquisa
27.34%
Prior research demonstrates that animals and humans share an approximate number system (ANS), characterized by ratio dependence and that the precision of this system increases substantially over human development. The goal of the present research was to investigate the malleability of the ANS (as measured by Weber fraction) in adult subjects in response to feedback and to explore the relationship between ANS acuity and acuity on another magnitude comparison task. We tested each of 20 subjects over six 1-h sessions. The main findings were that (a) Weber fractions rapidly decreased when trial-by-trial feedback was introduced in the second session and remained stable over continued training, (b) Weber fractions remained steady when trial-by-trial feedback was removed in session 6, (c)Weber fractions from the number comparison task were positively correlated with Weber fractions from a line length comparison task, (d) improvement in Weber fractions in response to feedback for the number task did not transfer to the line length task, (e) finally, the precision of the ANS was positively correlated with math, but not verbal, standardized aptitude scores. Potential neural correlates of the perceptual information and decision processes are considered...

Outer Domain of HIV-1 gp120: Antigenic Optimization, Structural Malleability, and Crystal Structure with Antibody VRC-PG04

Joyce, M. Gordon; Kanekiyo, Masaru; Xu, Ling; Biertümpfel, Christian; Boyington, Jeffrey C.; Moquin, Stephanie; Shi, Wei; Wu, Xueling; Yang, Yongping; Yang, Zhi-Yong; Zhang, Baoshan; Zheng, Anqi; Zhou, Tongqing; Zhu, Jiang; Mascola, John R.; Kwong, Peter
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /02/2013 EN
Relevância na Pesquisa
27.04%
The outer domain of the HIV-1 gp120 envelope glycoprotein contains the epitope for broadly neutralizing antibodies directed to the CD4-binding site, many of which are able to neutralize over 90% of circulating HIV-1 isolates. While the outer domain is conformationally more stable than other portions of the HIV-1 envelope, efforts to express the outer domain as an immunogen for eliciting broadly neutralizing antibodies have not been successful, potentially because natural outer domain variants do not bind strongly to antibodies such as VRC01. In this study, we optimized the antigenic properties of the HIV-1 Env outer domain to generate OD4.2.2, from the KER2018 strain of clade A HIV-1, enabling it to bind antibodies such as VRC01 with nanomolar affinity. The crystal structure of OD4.2.2 in complex with VRC-PG04 was solved at 3.0-Å resolution and compared to known crystal structures including (i) the structure of core gp120 bound by VRC-PG04 and (ii) a circularly permutated version of the outer domain in complex with antibody PGT128. Much of the VRC-PG04 epitope was preserved in the OD4.2.2 structure, though with altered N and C termini conformations. Overall, roughly one-third of the outer domain structure appeared to be fixed in conformation...

The development and malleability of executive control abilities

Hsu, Nina S.; Novick, Jared M.; Jaeggi, Susanne M.
Fonte: Frontiers Media S.A. Publicador: Frontiers Media S.A.
Tipo: Artigo de Revista Científica
Publicado em 24/06/2014 EN
Relevância na Pesquisa
27.04%
Executive control (EC) generally refers to the regulation of mental activity. It plays a crucial role in complex cognition, and EC skills predict high-level abilities including language processing, memory, and problem solving, as well as practically relevant outcomes such as scholastic achievement. EC develops relatively late in ontogeny, and many sub-groups of developmental populations demonstrate an exaggeratedly poor ability to control cognition even alongside the normal protracted growth of EC skills. Given the value of EC to human performance, researchers have sought means to improve it through targeted training; indeed, accumulating evidence suggests that regulatory processes are malleable through experience and practice. Nonetheless, there is a need to understand both whether specific populations might particularly benefit from training, and what cortical mechanisms engage during performance of the tasks used in the training protocols. This contribution has two parts: in Part I, we review EC development and intervention work in select populations. Although promising, the mixed results in this early field make it difficult to draw strong conclusions. To guide future studies, in Part II, we discuss training studies that have included a neuroimaging component – a relatively new enterprise that also has not yet yielded a consistent pattern of results post-training...

Computational Modeling Reveals Key Contributions of KCNQ and hERG Currents to the Malleability of Uterine Action Potentials Underpinning Labor

Tong, Wing-Chiu; Tribe, Rachel M.; Smith, Roger; Taggart, Michael J.
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 04/12/2014 EN
Relevância na Pesquisa
27.04%
The electrical excitability of uterine smooth muscle cells is a key determinant of the contraction of the organ during labor and is manifested by spontaneous, periodic action potentials (APs). Near the end of term, APs vary in shape and size reflecting an ability to change the frequency, duration and amplitude of uterine contractions. A recent mathematical model quantified several ionic features of the electrical excitability in uterine smooth muscle cells. It replicated many of the experimentally recorded uterine AP configurations but its limitations were evident when trying to simulate the long-duration bursting APs characteristic of labor. A computational parameter search suggested that delayed rectifying K+ currents could be a key model component requiring improvement to produce the longer-lasting bursting APs. Of the delayed rectifying K+ currents family it is of interest that KCNQ and hERG channels have been reported to be gestationally regulated in the uterus. These currents exhibit features similar to the broadly defined uterine IK1 of the original mathematical model. We thus formulated new quantitative descriptions for several IKCNQ and IhERG. Incorporation of these currents into the uterine cell model enabled simulations of the long-lasting bursting APs. Moreover...

Learning-Induced Plasticity in Medial Prefrontal Cortex Predicts Preference Malleability

Garvert, Mona M.; Moutoussis, Michael; Kurth-Nelson, Zeb; Behrens, Timothy E.J.; Dolan, Raymond J.
Fonte: Cell Press Publicador: Cell Press
Tipo: Artigo de Revista Científica
Publicado em 21/01/2015 EN
Relevância na Pesquisa
27.04%
Learning induces plasticity in neuronal networks. As neuronal populations contribute to multiple representations, we reasoned plasticity in one representation might influence others. We used human fMRI repetition suppression to show that plasticity induced by learning another individual’s values impacts upon a value representation for oneself in medial prefrontal cortex (mPFC), a plasticity also evident behaviorally in a preference shift. We show this plasticity is driven by a striatal “prediction error,” signaling the discrepancy between the other’s choice and a subject’s own preferences. Thus, our data highlight that mPFC encodes agent-independent representations of subjective value, such that prediction errors simultaneously update multiple agents’ value representations. As the resulting change in representational similarity predicts interindividual differences in the malleability of subjective preferences, our findings shed mechanistic light on complex human processes such as the powerful influence of social interaction on beliefs and preferences.

Aid, Agency, and the Malleability of International Law: The Post-2003 Iraqi Refugee Crisis

Goldenziel, Jill Iris
Fonte: Harvard University Publicador: Harvard University
Tipo: Thesis or Dissertation
EN_US
Relevância na Pesquisa
27.04%
Why do states tolerate large numbers of refugees? This dissertation offers an answer to this puzzle by examining changes in policy responses by the international community toward Iraqis displaced after the U.S. invasion of 2003. From 2003-2006, Jordan, Syria, and Egypt remained quiet about the growing humanitarian needs of displaced Iraqis. From 2007-2010, these countries abruptly shifted policy to claim that they were hosting millions of Iraqis, and to allow Iraqis greater access to public goods and humanitarian assistance. I argue that this policy shift occurred because of new opportunities to extract strategic rents from the international community in the form of foreign aid and development assistance tied to the presence of refugees. I also explain how and why the UN Refugee Agency facilitated host country behavior during these two time periods, even in contradiction with its mandate under international law. I ground my argument in more than 100 interviews with UN Agency officials, NGO workers, government officials, and Iraqi refugees conducted in Jordan, Syria, and Egypt and at the UN Refugee Agency Headquarters in Geneva between 2007 and 2010. I also utilize research in the archives of relevant newspapers, national departments of statistics...

Bounded CCA2-Secure Non-Malleable Encryption

Pass, Rafael; Shelat, Abhi; Vaikuntanathan, Vinod
Fonte: MIT - Massachusetts Institute of Technology Publicador: MIT - Massachusetts Institute of Technology
Formato: 17 p.; 1222225 bytes; 239045 bytes; application/postscript; application/pdf
EN_US
Relevância na Pesquisa
27.34%
Under an adaptive chosen ciphertext attack (CCA2), the security of an encryption scheme must hold against adversaries that have access to a decryption oracle. We consider a weakening of CCA2 security, wherein security need only hold against adversaries making an a-priori bounded number of queries to the decryption oracle. Concerning this notion, which we call bounded-CCA2 security, we show the following two results. (1) Bounded-CCA2 secure non-malleable encryption schemes exist if and only if semantically-secure (IND-CPA-secure) encryption schemes exist.(As far as we know, bounded-CCA2 non-malleability is the strongest notion of security known to be satisfiable assuming only the existence of semantically-secure encryption schemes.) (2) In contrast to CCA2 security, bounded-CCA2 security alone does not imply non-malleability. In particular, if there exists an encryption scheme that is bounded-CCA2 secure, then there exists another encryption scheme which remains bounded-CCA2 secure, but is malleable under a simple chosen-plaintext attack.

Flexibilidad y maleabilidad de los objetos de diseño en tres centros comerciales de Cali

Franco, Joaquín Llorca; Fernández, César Eduardo Ibáñez
Fonte: Universidad Católica de Colombia Publicador: Universidad Católica de Colombia
ES
Relevância na Pesquisa
27.04%
En este artículo se describen los grados de flexibilidad y maleabilidad en los objetos de diseño presentes en los accesos y las plazoletas de tres centros comerciales de la ciudad de Cali (Unicentro Cali, Cosmocentro y Supercentro Calima), el estudio se desarrolló a partir de tres aspectos, primero, la revisión bibliográfica como marco conceptual, segundo, una labor etnográfica para exponerlo como un escenario en el cual lo público se convierte en un lugar de lo efímero y, tercero, determinar el centro comercial como espacio flexible mostrando con ello en qué medida es evidente la presencia de desarrollos preconcebidos en términos del diseño, como también de una racionalidad económica en el carácter de los objetos de diseño como mediadores sociales. Con el estudio se puede ver la importancia que ha cobrado la movilidad o flexibilidad de las estructuras físicas y los equipamientos de los centros comerciales como variable de diseño a la hora de responder a unos requerimientos de consumo cada vez más efímeros.; In this article the grades of flexibility and malleability are described in the design objects you present in the accesses and the plazas of three business centers of the city of Cali (Unicentro Cali, Cosmocentro and Supercentro Calima)...

Providing adaptability to MPI applications on current parallel architectures; Provendo adaptabilidade em aplicações MPI nas arquiteturas paralelas atuais

Cera, Marcia Cristina
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Tese de Doutorado Formato: application/pdf
ENG
Relevância na Pesquisa
27.34%
Atualmente, adaptabilidade é uma característica desejada em aplicações paralelas. Por exemplo, o crescente número de usuários competindo por recursos em arquiteturas paralelas gera mudanças constantes no conjunto de processadores disponíveis. Aplicações adaptativas são capazes de executar usando um conjunto volátil de processadores, oferecendo urna melhor utilização dos recursos. Este comportamento adaptativo é conhecido corno maleabilidade. Outro exemplo vem da constante evolução das arquiteturas multi-core, as quais aumentam o número de cores em seus chips a cada nova geração. Adaptabilidade é a chave para permitir que os programas paralelos sejam portáveis de uma máquina a outra. Assim. os programas paralelos são capazes de adaptar a extração do paralelismo de acordo com o grau de paralelismo específico da arquitetura alvo. Este comportamento pode ser visto como um caso particular de evolutividade. Nesse sentido, esta tese está focada em: (i) maleabilidade para adaptar a execução das aplicações paralelas às mudanças na disponibilidade dos processadores; e (ii) evolutividade para adaptar a extração do paralelismo de acordo com propriedades da arquitetura e dos dados de entrada. Portanto, a questão remanescente é "Como prover e suportar aplicações adaptativas?". Esta tese visa responder tal questão com base no MPI (Message-Passing Interface)...

Adaptive Concurrent Non-Malleability with Bare Public-Keys

Yao, Andrew C.; Yung, Moti; Zhao, Yunlei
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 17/10/2009
Relevância na Pesquisa
27.34%
Concurrent non-malleability (CNM) is central for cryptographic protocols running concurrently in environments such as the Internet. In this work, we formulate CNM in the bare public-key (BPK) model, and show that round-efficient concurrent non-malleable cryptography with full adaptive input selection can be established, in general, with bare public-keys (where, in particular, no trusted assumption is made). Along the way, we clarify the various subtleties of adaptive concurrent non-malleability in the bare public-key model.; Comment: 41 pages

Bitcoin Transaction Malleability and MtGox

Decker, Christian; Wattenhofer, Roger
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 26/03/2014
Relevância na Pesquisa
27.64%
In Bitcoin, transaction malleability describes the fact that the signatures that prove the ownership of bitcoins being transferred in a transaction do not provide any integrity guarantee for the signatures themselves. This allows an attacker to mount a malleability attack in which it intercepts, modifies, and rebroadcasts a transaction, causing the transaction issuer to believe that the original transaction was not confirmed. In February 2014 MtGox, once the largest Bitcoin exchange, closed and filed for bankruptcy claiming that attackers used malleability attacks to drain its accounts. In this work we use traces of the Bitcoin network for over a year preceding the filing to show that, while the problem is real, there was no widespread use of malleability attacks before the closure of MtGox.

Small primitive roots and malleability of RSA moduli

Dieulefait, Luis; Urroz, Jorge Jimenez
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 28/12/2007
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27.34%
In a paper of P. Paillier and J. Villar a conjecture is made about the malleability of an RSA modulus. In this paper we present an explicit algorithm refuting the conjecture. Concretely we can factorize an RSA modulus n using very little information on the factorization of a concrete n' coprime to n. However, we believe the conjecture might be true, when imposing some extra conditions on the auxiliary n' allowed to be used. In particular, the paper shows how subtle the notion of malleability is.

Some Measurements of Nullable and Non-Nullable Parameter Declarations in Relation to Software Malleability

Harrison, William; Walsh, Tim; Biggar, Paul
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 24/08/2011
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27.52%
The usual advantages put forward for including nullability declarations in the type systems of programming languages are that they improve program reliability or performance. But there is another, entirely different, reason for doing so. In the right context, this information enables the software artifacts we produce, the objects and methods, to exhibit much greater malleability. For declaratively typed languages, we can obtain greater software malleability by extending the model of method call so that assurance of a method's availability can be provided by any non-nullable parameter, not simply the target parameter, and by allowing the method's implementation to reside in classes or objects other than the target.. This paper examines the question of whether this hypothetical improvement in software malleability is consistent with existing programming practice by examining the question of the extent to which methods in existing software have multiplicities of non-nullable parameters. The circumstance occurs frequently enough to provide an important reason to introduce declarations of nullability into programming languages.