955 research outputs found
Soliton Staircases and Standing Strain Waves in Confined Colloidal Crystals
We show by computer simulation of a two-dimensional crystal confined by
corrugated walls that confinement can be used to impose a controllable
mesoscopic superstructure of predominantly mechanical elastic character. Due to
an interplay of the particle density of the system and the width D of the
confining channel, "soliton staircases" can be created along both parallel
confining boundaries, that give rise to standing strain waves in the entire
crystal. The periodicity of these waves is of the same order as D. This
mechanism should be useful for structure formation in the self-assembly of
various nanoscopic materials.Comment: 22 pages, 5 figure
Transcriptomic and Exometabolomic Profiling Reveals Antagonistic and Defensive Modes of Clonostachys rosea Action Against Fusarium graminearum
The mycoparasite Clonostachys rosea ACM941 is under development as a biocontrol organism against Fusarium graminearum, the causative agent of Fusarium head blight in cereals. To identify molecular factors associated with this interaction, the transcriptomic and exometabolomic profiles of C. rosea and F. graminearum GZ3639 were compared during coculture. Prior to physical contact, the antagonistic activity of C. rosea correlated with a response heavily dominated by upregulation of polyketide synthase gene clusters, consistent with the detected accumulation of corresponding secondary metabolite products. Similarly, prior to contact, trichothecene gene clusters were upregulated in F. graminearum, while those responsible for fusarielin and fusarin biosynthesis were downregulated, correlating with an accumulation of trichothecene products in the interaction zone over time. A concomitant increase in 15-acetyl deoxynivalenol-3-glucoside in the interaction zone was also detected, with C. rosea established as the source of this detoxified mycotoxin. After hyphal contact, C. rosea was found to predominantly transcribe genes encoding cell wall–degradation enzymes, major facilitator superfamily sugar transporters, anion:cation symporters, as well as alternative carbon source utilization pathways, together indicative of a transition to necrotropism at this stage. F. graminearum notably activated the transcription of phosphate starvation pathway signature genes at this time. Overall, a number of signature molecular mechanisms likely contributing to antagonistic activity by C. rosea against F. graminearum, as well as its mycotoxin tolerance, are identified in this report, yielding several new testable hypotheses toward understanding the basis of C. rosea as a biocontrol agent for continued agronomic development and application
pH Biosensing by PI4P Regulates Cargo Sorting at the TGN
Phosphoinositides, diacylglycerolpyrophosphate, ceramide-1-phosphate, and phosphatidic acid belong to a unique class of membrane signaling lipids that contain phosphomonoesters in their headgroups having pKa values in the physiological range. The phosphomonoester headgroup of phosphatidic acid enables this lipid to act as a pH biosensor as changes in its protonation state with intracellular pH regulate binding to effector proteins. Here, we demonstrate that binding of pleckstrin homology (PH) domains to phosphatidylinositol 4-phosphate (PI4P) in the yeast trans-Golgi network (TGN) is dependent on intracellular pH, indicating PI4P is a pH biosensor. pH biosensing by TGN PI4P in response to nutrient availability governs protein sorting at the TGN, likely by regulating sterol transfer to the TGN by Osh1, a member of the conserved oxysterol-binding protein (OSBP) family of lipid transfer proteins. Thus, pH biosensing by TGN PI4P allows for direct metabolic regulation of protein trafficking and cell growth
Extended sedimentation profiles in charged colloids: the gravitational length, entropy, and electrostatics
We have measured equilibrium sedimentation profiles in a colloidal model
system with confocal microscopy. By tuning the interactions, we have determined
the gravitational length in the limit of hard-sphere-like interactions, and
using the same particles, tested a recent theory [R.van Roij, J. Phys. Cond.
Mat. 15, S3569, (2003)], which predicts a significantly extended sedimentation
profile in the case of charged colloids with long-ranged repulsions, due to a
spontaneously formed macroscopic electric field. For the hard-sphere-like
system we find that the gravitational length matches that expected. By tuning
the buoyancy of the colloidal particles we have shown that a mean field
hydrostatic equilibrium description even appears to hold in the case that the
colloid volume fraction changes significantly on the length scale of the
particle size. The extended sedimentation profiles of the colloids with
long-ranged repulsions are well-described by theory. Surprisingly, the theory
even seems to hold at concentrations where interactions between the colloids,
which are not modeled explicitly, play a considerable role
Формування законодавчої і нормативної бази архівної справи в республіці Казахстан
Аналізується законодавство Республіки Казахстан, спрямоване на забезпечення збереження документальної спадщини, регулювання діяльності архівної системи в умовах державного суверенітету. Визначаються особливості
архівного законодавства кінця 1990-х рр., прослідковуються його зміни та
напрями удосконалення в 2000-х рр., процеси формування нормативної бази
архівної справи.Анализируется законодательство Республики Казахстан, направленное на
обеспечение сохранности документального наследия, регулирование деятельности
архивной системы в условиях государственного суверенитета. Определяются
особенности архивного законодательства конца 1990-х гг., прослеживаются
его изменения и направления усовершенствования в 2000- х гг.,
процессы формирования нормативной базы архивного дела.The legislation of Republic of Kazakhstan, directed on providing of safety of
documentary legacy, adjusting of activity of the archival system in the conditions of
the state sovereignty is analysed in the article. The features of the archival legislation
the end of 1990-th are determined, its changes and directions of improvement in
the 2000-th, the processes of forming of normative base of the archival affairs are
traced
Employing culturally responsive pedagogy to foster literacy learning in schools
In recent years it has become increasingly obvious that, to enable students in schools from an increasingly diverse range of cultural backgrounds to acquire literacy to a standard that will support them to achieve academically, it is important to adopt pedagogy that is responsive to, and respectful of, them as culturally situated. What largely has been omitted from the literature, however, is discussion of a relevant model of learning to underpin this approach. For this reason this paper adopts a socio-cultural lens (Vygotsky, 1978) through which to view such pedagogy and refers to a number of seminal texts to justify of its relevance. Use of this lens is seen as having a particular rationale. It forces a focus on the agency of the teacher as a mediator of learning who needs to acknowledge the learner’s cultural situatedness (Kozulin, 2003) if school literacy learning for all students is to be as successful as it might be. It also focuses attention on the predominant value systems and social practices that characterize the school settings in which students’ literacy learning is acquired. The paper discusses implications for policy and practice at whole-school, classroom and individual student levels of culturally-responsive pedagogy that is based on a socio-cultural model of learning. In doing so it draws on illustrations from the work of a number of researchers, including that of the author
Questioning cultural narratives of economic development—an investigation of Kitchener-Waterloo
The version of record [Spigel, B. & Bathelt, H. (2019). Questioning cultural narratives of economic development - An investigation of Kitchener-Waterloo. Canadian Geographer, 63(2), 267-283.] is available online at:
https://onlinelibrary.wiley.com/doi/abs/10.1111/cag.12512This paper investigates the relationship between culture and economy and scrutinizes cultural narratives of economic development in Kitchener-Waterloo, southern Ontario. It argues for the need to carefully conceptualize the link between culture and economic development to avoid boosting deterministic stereotypes. In the case of Kitchener-Waterloo, a notable hub of high-technology firms and technology development, a link is frequently drawn between the German community and culture and the region’s technology economy and entrepreneurial culture. A social capital analysis, however, reveals that the German ethnic community neither has the strong professional internal ties nor the external social ties to other regional communities that could constitute a lead role in economic development. Rather, the legacy of Kitchener-Waterloo’s ethnic German population has been absorbed into the region’s self-image and creates a feeling of belonging and common reference points for joint social and economic initiatives in the region
Changes in healthcare costs following genome-wide sequencing for children with developmental disorders and early onset seizures in England and Canada
Importance Etiologic diagnoses for rare diseases can involve a diagnostic odyssey, with repeated health care interactions and inconclusive diagnostics. Prior studies reported cost savings associated with genome-wide sequencing (GWS) compared with cytogenetic or molecular testing through rapid genetic diagnosis, but there is limited evidence on whether diagnosis from GWS is associated with reduced health care costs.
Objective To measure changes in health care costs after diagnosis from GWS for Canadian and English children with suspected rare diseases.
Design, Setting, and Participants This cohort study was a quasiexperimental retrospective analysis across 3 distinct English and Canadian cohorts, completed in 2023. Mixed-effects generalized linear regression was used to estimate associations between GWS and costs in the 2 years before and after GWS. Difference-in-differences regression was used to estimate associations of genetic diagnosis and costs. Costs are in 2019 US dollars. GWS was conducted in a research setting (Genomics England 100 000 Genomes Project [100KGP] and Clinical Assessment of the Utility of Sequencing and Evaluation as a Service [CAUSES] Research Clinic) or clinical outpatient setting (publicly reimbursed GWS in British Columbia [BC], Canada). Participants were children with developmental disorders, seizure disorders, or both undergoing GWS between 2014 and 2019. Data were analyzed from April 2021 to September 2023.
Exposures GWS and genetic diagnosis.
Main Outcomes and Measures Annual health care costs and diagnostic costs per child.
Results Study cohorts included 7775 patients in 100KGP, among whom 788 children had epilepsy (mean [SD] age at GWS, 11.6 [11.1] years; 400 female [50.8%]) and 6987 children had an intellectual disability (mean [SD] age at GWS, 8.2 [8.4] years; 2750 female [39.4%]); 77 patients in CAUSES (mean [SD] age at GWS, 8.5 [4.4] years; 33 female [42.9%]); and 118 publicly reimbursed GWS recipients from BC (mean [SD] age at GWS, 5.5 [5.2] years; 58 female [49.2%]). GWS diagnostic yield was 143 children (18.1%) for those with epilepsy and 1323 children (18.9%) for those with an intellectual disability in 100KGP, 47 children (39.8%) in the BC publicly reimbursed setting, and 42 children (54.5%) in CAUSES. Mean annual per-patient spending over the study period was 5121-3373 (95% CI, 3424) for intellectual disability in the 100KGP, 563-1573 (95% CI, 1773) in the BC reimbursed setting. Receiving a genetic diagnosis from GWS was not associated with changed costs in any cohort.
Conclusions and Relevance In this study, receiving a genetic diagnosis was not associated with cost savings. This finding suggests that patient benefit and cost-effectiveness should instead drive GWS implementation
Astronomical Spectroscopy
Spectroscopy is one of the most important tools that an astronomer has for
studying the universe. This chapter begins by discussing the basics, including
the different types of optical spectrographs, with extension to the ultraviolet
and the near-infrared. Emphasis is given to the fundamentals of how
spectrographs are used, and the trade-offs involved in designing an
observational experiment. It then covers observing and reduction techniques,
noting that some of the standard practices of flat-fielding often actually
degrade the quality of the data rather than improve it. Although the focus is
on point sources, spatially resolved spectroscopy of extended sources is also
briefly discussed. Discussion of differential extinction, the impact of
crowding, multi-object techniques, optimal extractions, flat-fielding
considerations, and determining radial velocities and velocity dispersions
provide the spectroscopist with the fundamentals needed to obtain the best
data. Finally the chapter combines the previous material by providing some
examples of real-life observing experiences with several typical instruments.Comment: An abridged version of a chapter to appear in Planets, Stars and
Stellar Systems, to be published in 2011 by Springer. Slightly revise
Looking at Cities in Mexico with Crowds
Mobile and social technologies are providing new opportunities to document, characterize, and gather impressions of urban environments. In this paper, we present a study that examines urban perceptions of three cities in central Mexico (Guanajuato, Leon and Silao), which integrates a mobile crowdsourcing framework to collect geo-localized images of urban environments by a local youth community, and an online crowdsourcing platform (Amazon Mechanical Turk) to gather impressions of urban environments along twelve physical and psychological dimensions. Our study resulted in a collection of 7,000 geo-localized images containing outdoor scenes and views of each city's built environment, including touristic, historical, and residential neighbourhoods; and 156,000 individual judgments from MTurk. Statistical analyses show that outdoor environments can be reliably assessed with respect to most urban dimensions by the observers of crowdsourced images. Furthermore, a cross-city statistical analysis shows that outdoor urban places in Guanajuato (a touristic, cultural heritage site) are perceived as more quiet, picturesque and interesting compared to places in Leon and Silao, which are commercial and industrial hubs, respectively. In contrast Silao, is perceived to have lower accessibility than Leon. Finally, we investigate whether the perceptions of urban environments vary across different times of the day and found that places in the evening are perceived as less happy, pleasant and preserved, when compared to the same place in the morning. Through the use of collective action, participatory sensing and mobile crowdsourcing, our study engages citizens to understand socio-urban problems in their communities
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