8,183 research outputs found
Combinatorial Telescoping for an Identity of Andrews on Parity in Partitions
Following the method of combinatorial telescoping for alternating sums given
by Chen, Hou and Mu, we present a combinatorial telescoping approach to
partition identities on sums of positive terms. By giving a classification of
the combinatorial objects corresponding to a sum of positive terms, we
establish bijections that lead a telescoping relation. We illustrate this idea
by giving a combinatorial telescoping relation for a classical identity of
MacMahon. Recently, Andrews posed a problem of finding a combinatorial proof of
an identity on the q-little Jacobi polynomials which was derived based on a
recurrence relation. We find a combinatorial classification of certain triples
of partitions and a sequence of bijections. By the method of cancelation, we
see that there exists an involution for a recurrence relation that implies the
identity of Andrews.Comment: 12 pages, 5 figure
Characterization of Genotype by Planting Date Effects on Runner-Type Peanut Seed Germination and Vigor Response to Temperature
Experiments evaluated the genotype by environment effects on seed germination and vigor of the peanut runner-type cultivars ‘Georgia Green’, ‘AT3085R0’, ‘AT271516’, ‘Georgia 03L’, and ‘FR458’ grown under similar production practices, for three planting dates: April, May, and June in Georgia and Alabama. Objectives were to determine if time of planting and harvest dates would subsequently affect germination and vigor when tested using a thermal gradient devise (temperature range14 to 35 °C). Runner-type peanut seed grown in Dawson Georgia in 2008 had the strongest seed vigor with Germ80 of 22 to 40 growing degree days (GDD), and maximum incidence of germination rate 84.8-95.7% when planted April, May, and June 2008 across 15 seed lots. In contrast, seed harvested from plantings of May 2009 at Dawson Georgia exhibited Germ80 of 24 to 40 GDD with maximum incidence of germination rate 79.8-93.6%, but seed from April 2009 plantings had poor vigor of 56.8-72.8% and no amount of GDD could achieve Germ80, with similar results for June 2009 plantings for this location. For Headland April, May, and June 2009 plantings of the same cultivars, all seed had poor vigor, ≤75.6% maximum incidence for germination rate, and none obtained a measurable Germ80
Using a Pan-Viral Microarray Assay (Virochip) to Screen Clinical Samples for Viral Pathogens
The diagnosis of viral causes of many infectious diseases is difficult due to the inherent sequence diversity of viruses as well as the ongoing emergence of novel viral pathogens, such as SARS coronavirus and 2009 pandemic H1N1 influenza virus, that are not detectable by traditional methods. To address these challenges, we have previously developed and validated a pan-viral microarray platform called the Virochip with the capacity to detect all known viruses as well as novel variants on the basis of conserved sequence homology1. Using the Virochip, we have identified the full spectrum of viruses associated with respiratory infections, including cases of unexplained critical illness in hospitalized patients, with a sensitivity equivalent to or superior to conventional clinical testing2-5. The Virochip has also been used to identify novel viruses, including the SARS coronavirus6,7, a novel rhinovirus clade5, XMRV (a retrovirus linked to prostate cancer)8, avian bornavirus (the cause of a wasting disease in parrots)9, and a novel cardiovirus in children with respiratory and diarrheal illness10. The current version of the Virochip has been ported to an Agilent microarray platform and consists of ~36,000 probes derived from over ~1,500 viruses in GenBank as of December of 2009. Here we demonstrate the steps involved in processing a Virochip assay from start to finish (~24 hour turnaround time), including sample nucleic acid extraction, PCR amplification using random primers, fluorescent dye incorporation, and microarray hybridization, scanning, and analysis
Mercury Contamination in Forest and Freshwater Ecosystems in the Northeastern United States
Eastern North America receives elevated atmospheric mercury deposition from a combination of local, regional, and global sources. Anthropogenic emissions originate largely from electric utilities, incinerators, and industrial processes. The mercury species in these emissions have variable atmospheric residence times, which influence their atmospheric transport and deposition patterns. Forested regions with a prevalence of wetlands and of unproductive surface waters promote high concentrations of mercury in freshwater biota and thus are particularly sensitive to mercury deposition. Through fish consumption, humans and wildlife are exposed to methylmercury, which markedly bioaccumulates up the freshwater food chain. Average mercury concentrations in yellow perch fillets exceed the Environmental Protection Agency’s human health criterion across the region, and mercury concentrations are high enough in piscivorous wildlife to cause adverse behavioral, physiological, and reproductive effects. Initiatives are under way to decrease mercury emissions from electric utilities in the United States by roughly 70%
Nutrient Supply and Mercury Dynamics in Marine Ecosystems: A Conceptual Model
There is increasing interest and concern over the impacts of mercury (Hg) inputs to marine 32 ecosystems. One of the challenges in assessing these effects is that the cycling and trophic 33 transfer of Hg are strongly linked to other contaminants and disturbances. In addition to Hg, a 34 major problem facing coastal waters is the impacts of elevated nutrient, particularly nitrogen 35 (N), inputs. Increases in nutrient loading alter coastal ecosystems in ways that should change 36 the transport, transformations and fate of Hg, including increases in fixation of organic carbon 37 and deposition to sediments, decreases in the redox status of sediments and changes in fish 38 habitat. In this paper we present a conceptual model which suggests that increases in loading 39 of reactive N to marine ecosystems might alter Hg dynamics, decreasing bioavailabilty and 40 trophic transfer. This conceptual model is most applicable to coastal waters, but may also be 41 relevant to the pelagic ocean. We present information from case studies that both support and 42 challenge this conceptual model, including marine observations across a nutrient gradient; 43 results of a nutrient‐trophic transfer Hg model for pelagic and coastal ecosystems; observations 44 of Hg species, and nutrients from coastal sediments in the northeastern U.S.; and an analysis of 45 fish Hg concentrations in estuaries under different nutrient loadings. These case studies suggest 46 that changes in nutrient loading can impact Hg dynamics in coastal and open ocean ecosystems. 47 Unfortunately none of the case studies is comprehensive; each only addresses a portion of the 48 conceptual model and has limitations. Nevertheless, our conceptual model has important 49 management implications. Many estuaries near developed areas are impaired due to elevated 50 nutrient inputs. Widespread efforts are underway to control N loading and restore coastal 51 ecosystem function. An unintended consequence of nutrient control measures could be to 3 exacerbate 52 problems associated with Hg contamination. Additional focused research and 53 monitoring are needed to critically examine the link between nutrient supply and Hg 54 contamination of marine waters
On Folding and Twisting (and whatknot): towards a characterization of workspaces in syntax
Syntactic theory has traditionally adopted a constructivist approach, in
which a set of atomic elements are manipulated by combinatory operations to
yield derived, complex elements. Syntactic structure is thus seen as the result
or discrete recursive combinatorics over lexical items which get assembled into
phrases, which are themselves combined to form sentences. This view is common
to European and American structuralism (e.g., Benveniste, 1971; Hockett, 1958)
and different incarnations of generative grammar, transformational and
non-transformational (Chomsky, 1956, 1995; and Kaplan & Bresnan, 1982; Gazdar,
1982). Since at least Uriagereka (2002), there has been some attention paid to
the fact that syntactic operations must apply somewhere, particularly when
copying and movement operations are considered. Contemporary syntactic theory
has thus somewhat acknowledged the importance of formalizing aspects of the
spaces in which elements are manipulated, but it is still a vastly
underexplored area. In this paper we explore the consequences of
conceptualizing syntax as a set of topological operations applying over spaces
rather than over discrete elements. We argue that there are empirical
advantages in such a view for the treatment of long-distance dependencies and
cross-derivational dependencies: constraints on possible configurations emerge
from the dynamics of the system.Comment: Manuscript. Do not cite without permission. Comments welcom
Isolated endogenous Nocardia endophthalmitis after immunosuppression.
PURPOSE: This study is aimed to report a case of endogenous Nocardia endophthalmitis in the setting of immunosuppression from chronic steroid use.
METHODS: A case report was conducted.
RESULTS: A 79-year-old woman presented with decreased vision with floaters in the left eye. Ophthalmic examination revealed severe inflammation in the anterior chamber, vitreous opacities, and retinal detachment. Vitreous cultures grew Nocardia farcinica without any systemic foci of infection found during further workup. The patient was treated with intravitreal amikacin and oral trimethoprim-sulfamethoxazole, and her retinal detachment was later repaired in the operating room. The patient has since remained stable with no signs of retinal detachment or active infection.
CONCLUSIONS: Nocardia endophthalmitis is a rare, but serious intraocular infection that should be considered in the differential diagnosis in any immunosuppressed patient, including those receiving steroids, who presents with signs of intraocular infection
Physics at BES-III
This physics book provides detailed discussions on important topics in
-charm physics that will be explored during the next few years at \bes3 .
Both theoretical and experimental issues are covered, including extensive
reviews of recent theoretical developments and experimental techniques. Among
the subjects covered are: innovations in Partial Wave Analysis (PWA),
theoretical and experimental techniques for Dalitz-plot analyses, analysis
tools to extract absolute branching fractions and measurements of decay
constants, form factors, and CP-violation and \DzDzb-oscillation parameters.
Programs of QCD studies and near-threshold tau-lepton physics measurements are
also discussed.Comment: Edited by Kuang-Ta Chao and Yi-Fang Wan
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