5,468 research outputs found

    Deformation rings which are not local complete intersections

    Full text link
    We study the inverse problem for the versal deformation rings R(Γ,V)R(\Gamma,V) of finite dimensional representations VV of a finite group Γ\Gamma over a field kk of positive characteristic pp. This problem is to determine which complete local commutative Noetherian rings with residue field kk can arise up to isomorphism as such R(Γ,V)R(\Gamma,V). We show that for all integers n1n \ge 1 and all complete local commutative Noetherian rings W\mathcal{W} with residue field kk, the ring W[[t]]/(pnt,t2)\mathcal{W}[[t]]/(p^n t,t^2) arises in this way. This ring is not a local complete intersection if pnW{0}p^n\mathcal{W}\neq\{0\}, so we obtain an answer to a question of M. Flach in all characteristics.Comment: 16 page

    Safety and Effectiveness of Struvite from Black Water and Urine as a Phosphorus Fertilizer

    Get PDF
    To ensure food supply, phosphorus must be recycled, for which an appealing method is using struvite fertilizer from human excreta. One struvite from black water and another from urine were assessed for safety under Dutch regulations, and for effectiveness as P fertilizer in a maize field experiment and a literature review. Both struvites contained 12% P, 12% Mg, 6% N, and 0.5-1.5% of several micronutrients. Struvites did not exceed Dutch regulations for heavy metals or pathogens, and based on literature, organic toxins should be far below regulatory limits. In this study and 18 others, struvite appears to have similar effectiveness to soluble fertilizer. Early in the season, 200 kg P2O5 ha-1 of black water struvite and soluble phosphorus improved maize performance (

    Inverse Problems for deformation rings

    Full text link
    Let W\mathcal{W} be a complete local commutative Noetherian ring with residue field kk of positive characteristic pp. We study the inverse problem for the versal deformation rings RW(Γ,V)R_{\mathcal{W}}(\Gamma,V) relative to W\mathcal{W} of finite dimensional representations VV of a profinite group Γ\Gamma over kk. We show that for all pp and n1n \ge 1, the ring W[[t]]/(pnt,t2)\mathcal{W}[[t]]/(p^n t,t^2) arises as a universal deformation ring. This ring is not a complete intersection if pnW{0}p^n\mathcal{W}\neq\{0\}, so we obtain an answer to a question of M. Flach in all characteristics. We also study the `inverse inverse problem' for the ring W[[t]]/(pnt,t2)\mathcal{W}[[t]]/(p^n t,t^2); this is to determine all pairs (Γ,V)(\Gamma, V) such that RW(Γ,V)R_{\mathcal{W}}(\Gamma,V) is isomorphic to this ring.Comment: 17 pages; this paper is closely related to arXiv:1003.3143. In the third version, we added a new Section 5 with further example

    The Chameleon Architecture for Streaming DSP Applications

    Get PDF
    We focus on architectures for streaming DSP applications such as wireless baseband processing and image processing. We aim at a single generic architecture that is capable of dealing with different DSP applications. This architecture has to be energy efficient and fault tolerant. We introduce a heterogeneous tiled architecture and present the details of a domain-specific reconfigurable tile processor called Montium. This reconfigurable processor has a small footprint (1.8 mm2^2 in a 130 nm process), is power efficient and exploits the locality of reference principle. Reconfiguring the device is very fast, for example, loading the coefficients for a 200 tap FIR filter is done within 80 clock cycles. The tiles on the tiled architecture are connected to a Network-on-Chip (NoC) via a network interface (NI). Two NoCs have been developed: a packet-switched and a circuit-switched version. Both provide two types of services: guaranteed throughput (GT) and best effort (BE). For both NoCs estimates of power consumption are presented. The NI synchronizes data transfers, configures and starts/stops the tile processor. For dynamically mapping applications onto the tiled architecture, we introduce a run-time mapping tool

    The GREATS Hβ\beta+[OIII] Luminosity Function and Galaxy Properties at z8\mathbf{z\sim8}: Walking the Way of JWST

    Get PDF
    The James Webb Space Telescope will allow to spectroscopically study an unprecedented number of galaxies deep into the reionization era, notably by detecting [OIII] and Hβ\beta nebular emission lines. To efficiently prepare such observations, we photometrically select a large sample of galaxies at z8z\sim8 and study their rest-frame optical emission lines. Combining data from the GOODS Re-ionization Era wide-Area Treasury from Spitzer (GREATS) survey and from HST, we perform spectral energy distribution (SED) fitting, using synthetic SEDs from a large grid of photoionization models. The deep Spitzer/IRAC data combined with our models exploring a large parameter space enables to constrain the [OIII]+Hβ\beta fluxes and equivalent widths for our sample, as well as the average physical properties of z8z\sim8 galaxies, such as the ionizing photon production efficiency with log(ξion/erg1Hz)25.77\log(\xi_\mathrm{ion}/\mathrm{erg}^{-1}\hspace{1mm}\mathrm{Hz})\geq25.77. We find a relatively tight correlation between the [OIII]+Hβ\beta and UV luminosity, which we use to derive for the first time the [OIII]+Hβ\beta luminosity function (LF) at z8z\sim8. The z8z\sim8 [OIII]+Hβ\beta LF is higher at all luminosities compared to lower redshift, as opposed to the UV LF, due to an increase of the [OIII]+Hβ\beta luminosity at a given UV luminosity from z3z\sim3 to z8z\sim8. Finally, using the [OIII]+Hβ\beta LF, we make predictions for JWST/NIRSpec number counts of z8z\sim8 galaxies. We find that the current wide-area extragalactic legacy fields are too shallow to use JWST at maximal efficiency for z8z\sim8 spectroscopy even at 1hr depth and JWST pre-imaging to 30\gtrsim30 mag will be required.Comment: 13 pages, 9 figures, accepted for publication in MNRA

    Reproducibility of lymphovascular space invasion (LVSI) assessment in endometrial cancer

    Get PDF
    Aims Lymphovascular space invasion (LVSI) in endometrial cancer (EC) is an important prognostic variable impacting on a patient's individual recurrence risk and adjuvant treatment recommendations. Recent work has shown that grading the extent of LVSI further improves its prognostic strength in patients with stage I endometrioid EC. Despite this, there is little information on the reproducibility of LVSI assessment in EC. Therefore, we designed a study to evaluate interobserver agreement in discriminating true LVSI from LVSI mimics (Phase I) and reproducibility of grading extent of LVSI (Phase II). Methods and results Scanned haematoxylin and eosin (H&E) slides of endometrioid EC (EEC) with a predefined possible LVSI focus were hosted on a website and assessed by a panel of six European gynaecological pathologists. In Phase I, 48 H&E slides were included for LVSI assessment and in Phase II, 42 H&E slides for LVSI grading. Each observer was instructed to apply the criteria for LVSI used in daily practice. The degree of agreement was measured using the two-way absolute agreement average-measures intraclass correlation coefficient (ICC). Reproducibility of LVSI assessment (ICC = 0.64, P < 0.001) and LVSI grading (ICC = 0.62, P < 0.001) in EEC was substantial among the observers. Conclusions Given the good reproducibility of LVSI, this study further supports the important role of LVSI in decision algorithms for adjuvant treatment
    corecore