9,793 research outputs found
Galleries, Hall-Littlewood polynomials and structure constants of the spherical Hecke algebra
We provide a combinatorial description of the coefficients appearing in the
expansion of Hall-Littlewood polynomials in terms of monomial symmetric
functions. We also give a Littlewood-Richardson rule for Hall-Littlewood
polynomials. For proving this we use galleries to calculate Satake coefficients
and structure constants of spherical Hecke algebras with arbitrary parameters.Comment: 28 pages, v3: revised version, to appear in IMR
The SDSS-GALEX viewpoint of the truncated red sequence in field environments at z~0
We combine GALEX near-UV photometry with a volume-limited sample of local
(0.005<z<0.037) SDSS DR4 galaxies to examine the composition and the
environmental dependencies of the optical and UV-optical colour-magnitude (C-M)
diagrams. We find that ~30% of red sequence galaxies in the optical C-M diagram
show signs of ongoing star-formation from their spectra having EW(Halpha)>2A.
This contamination is greatest at faint magnitudes (Mr>-19) and in field
regions where as many as three-quarters of red sequence galaxies are
star-forming, and as such has important consequences for following the build-up
of the red sequence. We find that the NUV-r colour instead allows a much more
robust separation of passively-evolving and star-forming galaxies, which allows
the build-up of the UV-selected red sequence with redshift and environment to
be directly interpreted in terms of the assembly of stellar mass in
passively-evolving galaxies. We find that in isolated field regions the number
density of UV-optical red sequence galaxies declines rapidly at magnitudes
fainter than Mr~-19 and appears completely truncated at Mr~-18. This confirms
the findings of Haines et al. (2007) that no passively-evolving dwarf galaxies
are found more than two virial radii from a massive halo, whether that be a
group, cluster or massive galaxy. These results support the downsizing paradigm
whereby the red sequence is assembled from the top down, being already largely
in place at the bright end by z~1, and the faint end filled in at later epochs
in clusters and groups through environment-related processes such as
ram-pressure stripping or galaxy harassment.Comment: 12 pages, 7 figures, MNRAS submitte
Affine Deligne-Lusztig varieties in affine flag varieties
This paper studies affine Deligne-Lusztig varieties in the affine flag
manifold of a split group. Among other things, it proves emptiness for certain
of these varieties, relates some of them to those for Levi subgroups, extends
previous conjectures concerning their dimensions, and generalizes the superset
method.Comment: 44 pages, 4 figures. Minor changes to font, references, and
acknowledgments. Improved introduction, other improvements in exposition, and
two new figures added, for a total of
Health and sustainable development
If sustainable development is to mean anything, people must be healthy enough to benefit from it and not have their lives cut off prematurely. Development without health is meaningless. But the processes which are likely to occur in a world undergoing globalisation, climate change, urbanisation, population increase and many other changes, will impact upon human health in complex ways. Some of them will benefit us, others will create new or augmented threats to survival and health, while many others will have a complex mixture of effects
Rediscovery and status of Cylindera (s. str.) lunalonga (Schaupp, 1884) (Coleoptera: Carabidae: Cicindelinae) in the San Joaquin Valley of California with a comparison to a Sierra Nevada population
Surveys for adult Cylindera (s. str.) lunalonga (Schaupp) (Coleoptera: Carabidae: Cicindelinae) were conducted between 2001 and 2011 at over 80 sites throughout the speciesâ historic range in the San Joaquin Valley and Sierra Nevada Mountains of California. Previously considered extirpated from the Valley, these surveys resulted in finding adults at 18 sites, several with large populations (>50 individuals). As suggested by historic records, our studies confirmed that the Valley populations of Cy. lunalonga occur in what were historically wetland sites, but are now lowland agricultural croplands. Adults were always associated with wet, muddy soil within and along the edges of irrigation ditches. A comparison of morphology, behavior, habitat, and conservation is made with the only known extant Sierra Nevada population
Access to Mobile Resources: How Does It Affect the Clerkship Experience?
Objectives: To evaluate the perceived benefits of access to library-licensed mobile clinical decision support resources in clinical medical education.
Methods: A cohort of medical students was surveyed midway through the clerkship year. Dana Medical Library offered instruction on clinical mobile resources at the beginning of the year. Students were offered a subject guide and assistance with authentication. Assessment methods included web analytics measuring the utility of the subject guide and a survey. Survey questions gathered data on access to mobile devices, relevance of instruction, use of library-licensed mobile resources, and benefits and barriers to their use in the clinical setting. Students were also asked whether access to mobile resources facilitated comparable educational experiences across clerkship sites.
Results: The survey was sent to all 111 students from the University of Vermont College of Medicine class of 2014; 31 completed the survey, with a completion rate of 28%. All respondents owned a mobile device, despite efforts to recruit both users and non-users. Nearly 75% of respondents reported using an iPhone. About 90% of respondents brought their mobile device on rotation. Generally, the wireless access at each clerkship site was rated good or excellent. Of the 60% of respondents who attended the instruction session on mobile resources, 94% found the class helpful. Half of the respondents looked at the Mobile Apps subject guide; 70% of those who did found it helpful. A significant increase in page views was reflected in subject guide usage statistics immediately following the instruction session. Approximately 25% of respondents sought out individual assistance at the library.
Conclusions: Respondents suggested improvements to library instruction such as distributing access codes during the class and demonstrating installation of an app. A large number of students did not seek additional assistance from the library, citing they did not have any questions. While that may be because they found the subject guide and/or class sufficiently helpful, a significant number of respondents indicated they were unaware of the subject guide. This suggests a need for further promotion and marketing efforts. Researchers were surprised that nonlibrary licensed apps (ePocrates or Medscape) were valued over resources such as DynaMed, and that the most common barrier cited was not having access to appropriate apps. Finally, almost all of the participants who reported taking a mobile device on a rotation agreed it facilitated access to clinical information and improved the clerkship experience
Quality programming for learning-disabled students : a comparison of microcomputer-assisted IEPS, manual-assisted IEPS, and teacher written IEPS
The purpose of this study was to determine which IEPs are of greater quality for learning-disabled students: teacher-written IEPs (those developed without the aid of microcomputers or manuals of goals and objectives); manual-assisted IEPs (those developed with the aid of manuals of goals and objectives); or microcomputer-assisted IEPs (those developed with the aid of both manuals of goals and objectives and microcomputers). This study investigated the question: What effect does the use of microcomputers and manuals of goals and objectives have upon the quality of IEPs developed for learning-disabled students?;The sample consisted of 120 IEPs of students categorized as learning-disabled by the North Central Regional Education Sevice Agency (RESA 7) of West Virginia. Forty of the IEPs were teacher-written, forty of the IEPs were manual-assisted, and forty of the IEPs were microcomputer-assisted. Three trained raters examined and evaluated, individually, all of the IEPs involved in the study with regard to legal requirements, relevance, and clarity using the Checklist For Documenting Appropriateness of the IEP.;A statistical analysis of the data collected regarding each hypothesis revealed the following findings: (1) A t test indicated that the microcomputer-assisted IEPs in this study received a significantly higher mean total score (p \u3c .01) on the Checklist For Documenting Appropriateness of the IEP than did the teacher-written IEPs in this study. as a result, the null hypothesis (that there was no difference in quality between microcomputer-assisted IEPs and teacher-written IEPs as evaluated using the Checklist For Documenting Appropriateness of the IEP) was rejected. (2) A t test indicated that the manual-assisted IEPs in this study received a significantly higher mean total score (p \u3c .01) on the Checklist For Documenting Appropriateness of the IEP than did the teacher-written IEPs in this study. as a result, the null hypothesis (that there was no difference in quality between manual-assisted IEPs and teacher-written IEPs as evaluated using the Checklist For Documenting Appropriateness of the IEP) was rejected. (3) A t test indicated that the microcomputer-assisted IEPs in this study received a significantly higher mean total score (p \u3c .01) on the Checklist For Documenting Appropriateness of the IEP than did the manual-assisted IEPs. as a result, the null hypothesis (that there was no significant difference in quality between manual-assisted IEPs and microcomputer-assisted IEPs as evaluated using the Checklist For Documenting Appropriateness of the IEP) was rejected
Dimensions of some affine Deligne-Lusztig varieties
This paper concerns the dimensions of certain affine Deligne-Lusztig
varieties, both in the affine Grassmannian and in the affine flag manifold.
Rapoport conjectured a formula for the dimensions of the varieties X_mu(b) in
the affine Grassmannian. We prove his conjecture for b in the split torus; we
find that these varieties are equidimensional; and we reduce the general
conjecture to the case of superbasic b. In the affine flag manifold, we prove a
formula that reduces the dimension question for X_x(b) with b in the split
torus to computations of dimensions of intersections of Iwahori orbits with
orbits of the unipotent radical. Calculations using this formula allow us to
verify a conjecture of Reuman in many new cases, and to make progress toward a
generalization of his conjecture.Comment: 51 pages, 12 figure
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