201 research outputs found
A general theory of intertemporal decision-making and the perception of time
Animals and humans make decisions based on their expected outcomes. Since
relevant outcomes are often delayed, perceiving delays and choosing between
earlier versus later rewards (intertemporal decision-making) is an essential
component of animal behavior. The myriad observations made in experiments
studying intertemporal decision-making and time perception have not yet been
rationalized within a single theory. Here we present a
theory-Training--Integrated Maximized Estimation of Reinforcement Rate
(TIMERR)--that explains a wide variety of behavioral observations made in
intertemporal decision-making and the perception of time. Our theory postulates
that animals make intertemporal choices to optimize expected reward rates over
a limited temporal window; this window includes a past integration interval
(over which experienced reward rate is estimated) and the expected delay to
future reward. Using this theory, we derive a mathematical expression for the
subjective representation of time. A unique contribution of our work is in
finding that the past integration interval directly determines the steepness of
temporal discounting and the nonlinearity of time perception. In so doing, our
theory provides a single framework to understand both intertemporal
decision-making and time perception.Comment: 37 pages, 4 main figures, 3 supplementary figure
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The Influence of Government Regulations on Content Management Systems: An Exploratory Study
The primary focus of this study was to determine why and how small businesses implement content management and to clarify the relationship of content management to regulatory compliance issues presented by the Health Insurance Portability and Accountability and Sarbanes-Oxley Act
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Detecting Memory Impairment in Deaf People: A New Test of Verbal Learning and Memory in British Sign Language
Objective
Most existing tests of memory and verbal learning in adults were created for spoken languages, and are unsuitable for assessing deaf people who rely on signed languages. In response to this need for sign language measures, the British Sign Language Verbal Learning and Memory Test (BSL-VLMT) was developed. It follows the format of the English language Hopkins Verbal Learning Test Revised, using standardized video-presentation with novel stimuli and instructions wholly in British Sign Language, and no English language requirement.
Method
Data were collected from 223 cognitively healthy deaf signers aged 50ā89 and 12 deaf patients diagnosed with dementia. Normative data percentiles were derived for clinical use, and receiver-operating characteristic curves computed to explore the clinical potential and diagnostic sensitivity and specificity.
Results
The test showed good discrimination between the normative and clinical samples, providing preliminary evidence of clinical utility for identifying learning and memory impairment in older deaf signers with neurodegeneration.
Conclusions
This innovative video testing approach transforms the ability to accurately detect memory impairments in deaf people and avoids the problems of using interpreters, with international potential for adapting similar tests into other signed languages
Enhancing the anti-angiogenic action of histone deacetylase inhibitors
<p>Abstract</p> <p>Background</p> <p>Histone deacetylase inhibitors (HDACIs) have many effects on cancer cells, such as growth inhibition, induction of cell death, differentiation, and anti-angiogenesis, all with a wide therapeutic index. However, clinical trials demonstrate that HDACIs are more likely to be effective when used in combination with other anticancer agents. Moreover, the molecular basis for the anti-cancer action of HDACIs is still unknown. In this study, we compared different combinations of HDACIs and anti-cancer agents with anti-angiogenic effects, and analysed their mechanism of action.</p> <p>Results</p> <p>Trichostatin A (TSA) and Ī±-interferon (IFNĪ±) were the most effective combination across a range of different cancer cell lines, while normal non-malignant cells did not respond in the same manner to the combination therapy. There was a close correlation between absence of basal p21<sup>WAF1 </sup>expression and response to TSA and IFNĪ± treatment. Moreover, inhibition of p21<sup>WAF1 </sup>expression in a p21<sup>WAF1</sup>-expressing breast cancer cell line by a specific siRNA increased the cytotoxic effects of TSA and IFNĪ±. <it>In vitro </it>assays of endothelial cell function showed that TSA and IFNĪ± decreased endothelial cell migration, invasion, and capillary tubule formation, without affecting endothelial cell viability. TSA and IFNĪ± co-operatively inhibited gene expression of some pro-angiogenic factors: vascular endothelial growth factor, hypoxia-inducible factor 1Ī± and matrix metalloproteinase 9, in neuroblastoma cells under hypoxic conditions. Combination TSA and IFNĪ± therapy markedly reduced tumour angiogenesis in neuroblastoma-bearing transgenic mice.</p> <p>Conclusion</p> <p>Our results indicate that combination TSA and IFNĪ± therapy has potent co-operative cytotoxic and anti-angiogenic activity. High basal p21<sup>WAF1 </sup>expression appears to be acting as a resistance factor to the combination therapy.</p
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Detecting cognitive impairment and dementia in Deaf people: The British Sign Language Cognitive Screening Test
To provide accurate diagnostic screening of deaf people who use signed communication, cognitive tests must be devised in signed languages with normative deaf samples. This article describes the development of the first screening test for the detection of cognitive impairment and dementia in deaf signers. The British Sign Language Cognitive Screening Test uses standardized video administration to screen cognition using signed, rather than spoken or written, instructions and a large norm-referenced sample of 226 deaf older people. Percentiles are provided for clinical comparison. The tests showed good reliability, content validity, and correlation with age, intellectual ability, and education. Clinical discrimination was shown between the normative sample and 14 deaf patients with dementia. This innovative testing approach transforms the ability to detect dementia in deaf people, avoids the difficulties of using an interpreter, and enables culturally and linguistically sensitive assessment of deaf signers, with international potential for adaptation into other signed languages
The Angola Gyre is a hotspot of dinitrogen fixation in the South Atlantic Ocean
Ā© The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Marshall, T., Granger, J., Casciotti, K. L., Dahnke, K., Emeis, K.-C., Marconi, D., McIlvin, M. R., Noble, A. E., Saito, M. A., Sigman, D. M., & Fawcett, S. E. The Angola Gyre is a hotspot of dinitrogen fixation in the South Atlantic Ocean. Communications Earth & Environment, 3(1), (2022): 151, https://doi.org/10.1038/s43247-022-00474-x.Biological dinitrogen fixation is the major source of new nitrogen to marine systems and thus essential to the oceanās biological pump. Constraining the distribution and global rate of dinitrogen fixation has proven challenging owing largely to uncertainty surrounding the controls thereon. Existing South Atlantic dinitrogen fixation rate estimates vary five-fold, with models attributing most dinitrogen fixation to the western basin. From hydrographic properties and nitrate isotope ratios, we show that the Angola Gyre in the eastern tropical South Atlantic supports the fixation of 1.4ā5.4 Tg N.aā1, 28-108% of the existing (highly uncertain) estimates for the basin. Our observations contradict model diagnoses, revealing a substantial input of newly-fixed nitrogen to the tropical eastern basin and no dinitrogen fixation west of 7.5ĖW. We propose that dinitrogen fixation in the South Atlantic occurs in hotspots controlled by the overlapping biogeography of excess phosphorus relative to nitrogen and bioavailable iron from margin sediments. Similar conditions may promote dinitrogen fixation in analogous ocean regions. Our analysis suggests that local iron availability causes the phosphorus-driven coupling of oceanic dinitrogen fixation to nitrogen loss to vary on a regional basis.This work was supported by the South African National Research Foundation (114673 and 130826 to T.M., 115335, 116142 and 129320 to S.E.F.); the US National Science Foundation (CAREER award, OCE-1554474 to J.G., OCE-1736652 to D.M.S. and K.L.C., OCE-05-26277 to K.L.C.); the German Federal Agency for Education and Research (DAAD-SPACES 57371082 to T.M.); the Royal Society (FLAIR fellowship to S.E.F.); and the University of Cape Town (T.M., J.G., S.E.F.). The authors also recognize the support of the South African Department of Science and Innovationās Biogeochemistry Research Infrastructure Platform (BIOGRIP)
MmeI: a minimal Type II restriction-modification system that only modifies one DNA strand for host protection
MmeI is an unusual Type II restriction enzyme that is useful for generating long sequence tags. We have cloned the MmeI restriction-modification (R-M) system and found it to consist of a single protein having both endonuclease and DNA methyltransferase activities. The protein comprises an amino-terminal endonuclease domain, a central DNA methyltransferase domain and C-terminal DNA recognition domain. The endonuclease cuts the two DNA strands at one site simultaneously, with enzyme bound at two sites interacting to accomplish scission. Cleavage occurs more rapidly than methyl transfer on unmodified DNA. MmeI modifies only the adenine in the top strand, 5ā²-TCCRAC-3ā². MmeI endonuclease activity is blocked by this top strand adenine methylation and is unaffected by methylation of the adenine in the complementary strand, 5ā²-GTYGGA-3ā². There is no additional DNA modification associated with the MmeI R-M system, as is required for previously characterized Type IIG R-M systems. The MmeI R-M system thus uses modification on only one of the two DNA strands for host protection. The MmeI architecture represents a minimal approach to assembling a restriction-modification system wherein a single DNA recognition domain targets both the endonuclease and DNA methyltransferase activities
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A core outcome set for aphasia treatment research: the ROMA consensus statement
Background: A core outcome set (COS; an agreed, minimum set of outcomes) was needed to address the heterogeneous measurement of outcomes in aphasia treatment research and to facilitate the production of transparent, meaningful and efficient outcome data.
Objective: The Research Outcome Measurement in Aphasia (ROMA) consensus statement provides evidence-based recommendations for the measurement of outcomes for adults with post-stroke aphasia within phase I-IV aphasia treatment studies.
Methods: This statement was informed by a four-year program of research which comprised investigation of stakeholder-important outcomes using consensus processes, a scoping review of aphasia outcome measurement instruments, and an international consensus meeting. This paper provides an overview of this process and presents the results and recommendations arising from the international consensus meeting.
Results: Five essential outcome constructs were identified: Language, communication, patient-reported satisfaction with treatment and impact of treatment, emotional wellbeing, and quality of life. Consensus was reached for the following measurement instruments: Language: The Western Aphasia Battery Revised (WAB-R) (74% consensus); emotional well-being: General Health Questionnaire (GHQ)-12 (83% consensus); quality of life: Stroke and Aphasia Quality of Life Scale (SAQOL-39) (96% consensus). Consensus was unable to be reached for measures of communication (where multiple measures exist) or patient-reported satisfaction with treatment or impact of treatment (where no measures exist).
Discussion: Harmonisation of the ROMA COS with other core outcome initiatives in stroke rehabilitation is discussed. Ongoing research and consensus processes are outlined.
Conclusion: The WAB-R, GHQ, and SAQOL-39 are recommended to be routinely included within phase I-IV aphasia treatment studies. This consensus statement has been endorsed by the Collaboration of Aphasia Trialists, the British Aphasiology Society, the German Society for Aphasia Research and Therapy, and the Royal College of Speech Language Therapists
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