6,675 research outputs found
Majorana Physics Through the Cabibbo Haze
We present a model in which the Supersymmetric Standard Model is augmented by
the family symmetry \bs{\m Z_7 \rtimes \m Z_3}. Motivated by , where
the charge two-thirds and neutral Dirac Yukawa matrices are related, we
propose, using family symmetry, a special form for the seesaw Majorana matrix;
it contains a squared correlated hierarchy, allowing it to mitigate the severe
hierarchy of the quark sector. It is reproduced naturally by the invariant
operators of \bs{\m Z_7 \rtimes \m Z_3}, with the hierarchy carried by
familon fields. In addition to relating the hierarchy of the to the sector, it contains a Gatto-Sartori-Tonin
like relation, predicts a normal hierarchy for Tri-bimaximal and Golden Ratio
mixings, and gives specific values for the light neutrino masses.Comment: 33 pages, 1 figure. This revised version omits a section where a
particular linear combination of dimension-five operators was mistakenly
claimed to produce the special form of the Majorana matrix. The main changes
are to the Introduction, Sec. 5.1 of the previous version, and Summary and
Conclusions. In addition to minor changes throughout, we have corrected an
erroneous sign in Eq. 1
Consequences of cell-to-cell P-glycoprotein transfer on acquired multidrug resistance in breast cancer: a cell population dynamics model
Cancer is a proliferation disease affecting a genetically unstable cell
population, in which molecular alterations can be somatically inherited by
genetic, epigenetic or extragenetic transmission processes, leading to a
cooperation of neoplastic cells within tumoral tissue. The efflux protein
P-glycoprotein (P gp) is overexpressed in many cancer cells and has known
capacity to confer multidrug resistance to cytotoxic therapies. Recently,
cell-to-cell P-gp transfers have been shown. Herein, we combine experimental
evidence and a mathematical model to examine the consequences of an
intercellular P-gp trafficking in the extragenetic transfer of multidrug
resistance from resistant to sensitive cell subpopulations. We report
cell-to-cell transfers of functional P-gp in co-cultures of a P-gp
overexpressing human breast cancer MCF-7 cell variant, selected for its
resistance towards doxorubicin, with the parental sensitive cell line. We found
that P-gp as well as efflux activity distribution are progressively reorganized
over time in co-cultures analyzed by flow cytometry. A mathematical model based
on a Boltzmann type integro-partial differential equation structured by a
continuum variable corresponding to P-gp activity describes the cell
populations in co-culture. The mathematical model elucidates the population
elements in the experimental data, specifically, the initial proportions, the
proliferative growth rates, and the transfer rates of P-gp in the sensitive and
resistant subpopulations. We confirmed cell-to-cell transfer of functional
P-gp. The transfer process depends on the gradient of P-gp expression in the
donor-recipient cell interactions, as they evolve over time. Extragenetically
acquired drug resistance is an additional aptitude of neoplastic cells which
has implications in the diagnostic value of P-gp expression and in the design
of chemotherapy regimensComment: 13 pages, 8 figures, 1 tabl
Relations entre lâexplicitation, lâanticipation et la performance
La recherche a consistĂ© Ă vĂ©rifier l'observation de Brown et Flavell (1987) selon laquelle les experts n'expliciteraient pas mieux leurs connaissances mĂ©tacognitives que les sujets moins performants. L'hypothĂšse de travail est que la relation entre l'explicitation et la performance serait non linĂ©aire et Ă©pouserait la forme d'une courbe normale en fonction de la performance alors que, Ă l'opposĂ©, la relation entre l'anticipation et la performance serait linĂ©aire et croissante. Les auteurs ont demandĂ© Ă 42 sujets en apprentissage de la conversation anglaise de discriminer deux mots semblables Ă l'Ă©coute. Les rĂ©sultats suggĂšrent que les verbalisations mĂ©tacognitives Ă propos de son propre processus cognitif pourraient avoir pour fonction de favoriser l'autorĂ©gulation de l'apprentissage.The objective of this research is to re-examine observations made by Brown and Flavell (1987) which state that experts do not explain their own metacognitive knowledge better than less expert subjects. The authors' working hypothesis is that the relation between explanations and performance is non-linear and could be described by a normal curve of performance while, in contrast, the relation between anticipation and performance is linear and increasing. The experimental task involved 42 subjects learning conversational English who were asked to discriminate between two similar sounding words. The results suggest that metacognitive verbalizations about one s own cognitive processes could facilitate self-regulation of learning.Esta investigaciĂŽn consistio en verificar la observacion de Brown y Flavell (1987) segiin la cual los especialistas no explicitan mejor sus conocimientos metacognoscitivos que las personas menos expertas. La hipotesis de trabajo es que la relation entre la explicitud y el desempeno no serfa lineal y tomaria la forma de una curva normal en funcion del desempeno mientras que, por el contrario, la relacion entre la anticipation y el desempeno seria lineal y creciente. Los autores solicitaron a 42 estudiantes de inglĂ©s conversacional que discriminaran entre dos palabras oralmente similares. Los resultados sugieren que las verbalizaciones metaco-gnoscitivas sobre su propio proceso cognoscitivo podrian tener por funcion el favorecer la au to regulation del aprendizaje.In dieser Arbeit ging es um die Verifizierung der Feststellung von Brown und Flavell (1987), nach welcher die Experten ihre metakognitiven Kenntnisse nicht besser in Worte fassen wĂčrden als weniger leistungsfĂ hige Studenten. Die Arbeitshypothese ist folgende: der Zusammenhang zwischen Darlegung und Leistung ist nicht linear, sondern hat die Form einer normalen leistungsbezogenen Kurve; demgegeniiber miisste der Zusammenhang zwischen Leistungserwartung und tatsĂąchlicher Leistung linear und steigend sein. Die Verfasser haben 42 Studenten der englischen Umgangssprache zwischen zwei Ăąhnlich klingenden WĂŽrtern unterscheiden lassen. Den Ergebnissen kann entnommen werden, dass metakognitive Aufierungen Ă»ber den eigenen Kognitionsprozess eine bessere Selbstregelung des Lernprozesses bezwecken
Involvement of small-scale dairy farms in an industrial supply chain: When production standards meet farm diversity
In certain contexts, dairy firms are supplied by small-scale family farms. Firms provide a set of technical and economic recommendations meant to help farmers meet their requirements in terms of the quantity and quality of milk collected. This study analyzes how such recommendations may be adopted by studying six farms in Brazil. All farms are beneficiaries of the country's agrarian reforms, but they differ in terms of how they developed their activities, their resources and their milk collection objectives. First, we built a technical and economic benchmark farm based on recommendations from a dairy firm and farmer advisory institutions. Our analysis of the farms' practices and technical and economic results show that none of the farms in the sample apply all of the benchmark recommendations; however, all farms specialized in dairy production observe the main underlying principles with regard to feeding systems and breeding. The decisive factors in whether the benchmark is adopted and successfully implemented are (i) access to the supply chain when a farmer establishes his activity, (ii) a grasp of reproduction and forage production techniques and (iii) an understanding of dairy cattle feed dietary rationing principles. The technical problems observed in some cases impact the farms' dairy performance and cash position; this can lead to a process of disinvestment. This dynamic of farms facing production standards suggests that the diversity of specialized livestock farmers should be taken into account more effectively through advisory approaches that combine basic zootechnical training with assistance in planning farm activities over the short and medium term. (Résumé d'auteur
T-Reqs: Tool Support for Managing Requirements in Large-Scale Agile System Development
T-Reqs is a text-based requirements management solution based on the git
version control system. It combines useful conventions, templates and helper
scripts with powerful existing solutions from the git ecosystem and provides a
working solution to address some known requirements engineering challenges in
large-scale agile system development. Specifically, it allows agile
cross-functional teams to be aware of requirements at system level and enables
them to efficiently propose updates to those requirements. Based on our
experience with T-Reqs, we i) relate known requirements challenges of
large-scale agile system development to tool support; ii) list key requirements
for tooling in such a context; and iii) propose concrete solutions for
challenges.Comment: Accepted for publication in Proc. of 26th IEEE Int. Requirements Eng.
Conf., Demo Track, Banff, Alberta, Canada, 201
Concept de rĂ©gulation dâune turbine hydroĂ©lectrique par dĂ©bit fortement variable
Le but principal Ă©tait de mettre en place un systĂšme de rĂ©gulation pour automatiser une centrale hydroĂ©lectrique existante. Dâautres objectifs Ă©taient lâinstallation de mesures permanentes et le monitoring Ă distance des kWh produits
Affect, Interpersonal Behaviour and Interpersonal Perception During Open-Label, Uncontrolled Paroxetine Treatment of People with Social Anxiety Disorder: A Pilot Study
Background: Laboratory-based research with community samples has suggested changes in affective, behavioural and cognitive processes as possible explanations for the effects of serotonergic medications. Examining the effects of serotonergic medications using an ecological momentary measure (such as event-contingent recording) in the daily lives of people with social anxiety disorder would contribute to establishing the effects of these medications on affect, behaviour and one form of cognition: perception of othersâ behaviour.
Methods: The present study assessed changes in affect, interpersonal behaviour and perception of othersâ behaviour in adults with social anxiety disorder using ecological momentary assessment at baseline and over 4 months of a single-arm, uncontrolled, open-label trial of treatment with the selective serotonin reuptake inhibitor paroxetine.
Results: Anxiety and concurrent depressive symptoms decreased. Participants also reported increased positive and decreased negative affect; increased agreeable and decreased quarrelsome behaviour; increased dominant and decreased submissive behaviour; and increased perception that others behaved agreeably toward them. Moreover, participants demonstrated reduced intraindividual variability in affect, interpersonal behaviour and perception of othersâ behaviour.
Limitations: Limitations included the lack of a placebo group, the inability to identify the temporal order of changes and the restricted assessment of extreme behaviour.
Conclusion: The results of the present study demonstrate changes during pharmacotherapy in the manifestation of affect, interpersonal behaviour and interpersonal perception in the daily lives of people with social anxiety disorder. Given the importance of interpersonal processes to social anxiety disorder, these results may guide future research seeking to clarify mechanisms of action for serotonergic medications
Study Protocol: A Randomized Controlled Trial of Patient Navigation-Activation to Reduce Cancer Health Disparities
Abstract Background Cancer health disparities affecting low-income and minority patients are well documented. Root-causes are multifactorial, including diagnostic and treatment delays, social and financial barriers, and poor communication. Patient navigation and communication coaching (activation) are potential interventions to address disparities in cancer treatment. The purpose of this clinical trial is to test the effectiveness of an intervention combining patient navigation and activation to improve cancer treatment. Methods/Design The Rochester Patient Navigation Research Program (PNRP) is a National Cancer Institute-sponsored, patient-level randomized trial (RCT) of patient navigation and activation, targeting newly-diagnosed breast and colorectal cancer patients in Rochester, NY. The goal of the program is to decrease cancer health disparities by addressing barriers to receipt of cancer care and promoting patient self-efficacy. The intervention uses trained, paraprofessional patient navigators recruited from the target community, and a detailed training and supervisory program. Recruited patients are randomly assigned to receive either usual care (except for baseline and follow-up questionnaires and interviews) or intervention. The intervention patients receive tailored assistance from their patient navigators, including phone calls, in-person meetings, and behind-the-scenes coordination of care. A total of 344 patients have been recruited. Outcomes measured at three month intervals include timeliness of care, patient adherence, patient satisfaction, quality of life, self-efficacy, health literacy, and cancer knowledge. Discussion This unique intervention combining patient navigation and patient activation is designed to address the multifactorial problem of cancer health disparities. If successful, this study will affect the design and implementation of patient navigation programs. Trials Registration clinicaltrials.gov identifier NCT00496678http://deepblue.lib.umich.edu/bitstream/2027.42/78254/1/1471-2407-10-551.xmlhttp://deepblue.lib.umich.edu/bitstream/2027.42/78254/2/1471-2407-10-551.pdfPeer Reviewe
Cracking Open the Black Box of Genetic Ancestry Testing
Stormfront, a well-known online forum for white nationalists, is a place for discussions about race, nation, and biology. We analyzed how members shared and discussed genetic ancestry tests (GATs), which revealed a complicated network of boundary maintenance, identity formation and justification, and biosociality within this online community. Using selection of seventy Stormfront threads discussing GAT results, this study employs primarily digital ethnographic methods to investigate how white nationalists navigate questions of self and community online. Using scientific concepts, genetic data, and multiple databases, white nationalists rely on the ambiguity of genetics and the black boxing of algorithms provided by testing companies to redefine white identity while also remaining committed to biologically-informed conceptions of race. This research raises important questions about the role of scientific data in racial formations
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