1,561 research outputs found
Grothendieck categories as a bilocalization of linear sites
We prove that the 2-category Grt of Grothendieck abelian categories with
colimit preserving functors and natural transformations is a bicategory of
fractions in the sense of Pronk of the 2-category Site of linear sites with
continuous morphisms of sites and natural transformations. This result can
potentially be used to make the tensor product of Grothendieck categories from
earlier work by Lowen, Shoikhet and the author into a bi-monoidal structure on
Grt
Gabriel-Ulmer duality for topoi and its relation with site presentations
Let be a regular cardinal. We study Gabriel-Ulmer duality when one
restricts the 2-category of locally -presentable categories with
-accessible right adjoints to its locally full sub-2-category of
-presentable Grothendieck topoi with geometric -accessible
morphisms. In particular, we provide a full understanding of the locally full
sub-2-category of the 2-category of -small cocomplete categories with
-colimit preserving functors arising as the corresponding 2-category of
presentations via the restriction. We analyse the relation of these
presentations of Grothendieck topoi with site presentations and we show that
the 2-category of locally -presentable Grothendieck topoi with
geometric -accessible morphisms is a reflective sub-bicategory of the
full sub-2-category of the 2-category of sites with morphisms of sites
genearated by the weakly -ary sites in the sense of Shulman [37].Comment: 25 page
On the tensor product of linear sites and Grothendieck categories
We define a tensor product of linear sites, and a resulting tensor product of
Grothendieck categories based upon their representations as categories of
linear sheaves. We show that our tensor product is a special case of the tensor
product of locally presentable linear categories, and that the tensor product
of locally coherent Grothendieck categories is locally coherent if and only if
the Deligne tensor product of their abelian categories of finitely presented
objects exists. We describe the tensor product of non-commutative projective
schemes in terms of Z-algebras, and show that for projective schemes our tensor
product corresponds to the usual product scheme.Comment: New sections 5.3 on the alpha-Deligne tensor product and 5.4 on
future prospect
Exponentiable Grothendieck categories in flat Algebraic Geometry
We introduce and describe the -category of
Grothendieck categories and flat morphisms between them. First, we show that
the tensor product of locally presentable linear categories
restricts nicely to . Then, we characterize exponentiable
objects with respect to : these are continuous Grothendieck
categories. In particular, locally finitely presentable Grothendieck categories
are exponentiable. Consequently, we have that, for a quasi-compact
quasi-separated scheme , the category of quasi-coherent sheaves
is exponentiable. Finally, we provide a family of examples
and concrete computations of exponentials.Comment: Minor revision. The proofs of Sec 5 have been expanded to make the
paper self containe
On the tensor product of well generated dg categories
We endow the homotopy category of well generated (pretriangulated) dg
categories with a tensor product satisfying a universal property. The resulting
monoidal structure is symmetric and closed with respect to the cocontinuous
RHom of dg categories (in the sense of To\"en [26]). We give a construction of
the tensor product in terms of localisations of dg derived categories, making
use of the enhanced derived Gabriel-Popescu theorem [21]. Given a regular
cardinal alpha, we define and construct a tensor product of homotopically
alpha-cocomplete dg categories and prove that the well generated tensor product
of alpha-continuous derived dg categories (in the sense of [21]) is the
alpha-continuous dg derived category of the homotopically alpha-cocomplete
tensor product. In particular, this shows that the tensor product of well
generated dg categories preserves alpha-compactness
Cytotoxic Activity of Essential Oils of Some Species from Lamiaceae Family
Cancer is considered one of the most lethal diseases in the world, with a prevalence of 439.2 cases and 163.5 deaths per 100,000 inhabitants, in the period from 2011 to 2015; this disease has a greater impact in underdeveloped countries. For the treatment of this disease, a combination of chemotherapy with surgery or radiation is generally used, however, it is not exempt from adverse effects or resistance of the tumor to this type of treatment, for this reason the search for new treatments is constant. The plants are a possible source to achieve this; Lamiaceae is a family of plants widely distributed on the planet and has been used traditionally for the treatment of different diseases, and various essential oils with the potential for cancer treatment have been isolated from this species. The scope of this review is to present 46 essential oils isolated from different species of Lamiaceae which have been tested against different cancer cell lines
Diagnostic Accuracy Study Comparing Hysterosalpingo-Foam Sonography and Hysterosalpingography for Fallopian Tube Patency Assessment
Introduction: Simplified ultrasound-based infertility protocols that appear to provide
enough information to plan effective management have been described. Thus, the objective of this
study is to compare the diagnostic accuracy of the hysterosalpingo-foam sonography (HyFoSy)
in tubal patency testing with the traditional hysterosalpngography (HSG) for establishing a new
diagnostic strategy in infertility. Material and Methods: Prospective observational diagnostic accuracy
was performed in a private fertility clinic in which 106 women undergoing a preconceptionally visit
were recruited. All of them had low risk for tubal disease, had performed an HSG and were negative
for Chlamydia trachomatis antibody. Main outcome measures were tubal patency and pain grade.
Results: Evaluation of tubal patency by HyFoSy showed a total concordance with the results of the
previous HSG in 72.6% (n = 77), and a total discordance for 4.7% (n = 6), with the inter-test agreement
Kappa equal to 0.57, which means moderate concordance. Among the patients, 59.1% did not report
pain during the procedure, while the remaining 48.1% indicated pain in different degrees; patients
usually report less pain and only 6.6% described more pain with HyFoSy than with HSG (OR 6.57
(CI 95% 3.11â13.89)). Clinical outcomes after performing HyFoSy were not affected. Conclusions:
HyFoSy is in concordance with HSG regarding tubal patency results and it is a less painful technique
than HSG. HyFoSy is more economical and can be performed in an exam room only equipped with
an ultrasound scanner. Based on these results, HyFoSy could be the first-choice diagnostic option to
assess tubal patency in patients with low risk of tubal disea
N- and S-doped carbons derived from polyacrylonitrile for gases separation
The CO2 capture using adsorption can reduce the carbon footprint, increasing the sustainability of the process without the production of wastes present in commonly used industrial operations. The present research work analyses the effect of the doping-agents incorporation in
carbon materials upon adsorption and separation of gases, specifically for carbon dioxide and nitrogen. The carbons precursor was polyacrylonitrile (PAN), which enabled the incorporation of nitrogen atoms in the structure, whereas sulphur doping was reached using pure sulphur after the carbonisation step. The influence of several variables (such as temperature or pressure) and characteristics of synthesised materials (mainly corresponding to surface characteristics) on carbon dioxide separation has been evaluated. Adsorption isotherms were determined for each gas (CO2 and N2) at different temperatures and pressures. Different adsorption models were evaluated to fit the experimental data. In general, the Toth isotherm described better the adsorption for both gases.
Important parameters such as CO2/N2 selectivity and heat of adsorption were determined using the IAS theory and the experimental isotherms at different temperatures, respectively. Non-activated carbons generated from PAN carbonisation without sulphur addition showed the highest values of
selectivity (up to 400) and adsorption heat (up to 40 kJ molâ1), mainly at low pressures and at low carbon dioxide uptakes, respectively. Furthermore, thanks to their high adsorption capacity, these carbons can be applied for carbon dioxide separation from mixtures with nitrogen
- âŠ