52 research outputs found
Word fibres in finite p-groups and pro-p groups
No full textGiven a group word w in k variables, a group GM and g ∈ G, we consider the set Sw(g) of k-tuples (g1,..., gk) ∈ G(k) such that w(g1,..., gk) = g and when G is finite, the size of Sw(g), Nw(g). N. Amit conjectured that for any finite nilpotent group G and any word in k variables, Nw(1) ≥ |G|k-1. In this thesis we first prove Amitâs conjecture for finite groups of nilpotency class 2. This was independently proved by Levy in [1]. More generally, we study the class functions Nw for this class of groups and show that the inequality can be improved to Nw(1) ≥ |G|k/|Gw (Gw is the set of w-values in G) if G has odd order. This last result is explained by the fact that the functions Nw are characters of G in this case. For groups of even order, all that can be said is that Nw is a generalized character, something that is false in general for groups of nilpotency class greater than 2. We characterize group theoretically when Nxn is a character if G is a 2-group of nilpotency class 2. We also address the (much harder) problem of studying if Nw(g) ≥ |G|k-1 for g ∈ Gw, proving that this is the case for the free p-groups of nilpotency class 2 and exponent p. Finally, we look at the analogous problem for finitely generated pro-p groups. Let G be a finitely generated pro-p group and {Gn} some filtration. We define the dimension of a closed subset H â G as Dim{Gn}(H) = lim infn→∞ logp | HG(k)n/ G(k)n|logp | (G / Gn)(k) | · In this setting, a rather natural way to define the metric is by using the filtration Gn = /\xpn : x ∈ G\/. For this filtration, we ask whether for any word w in k variables, Dim{Gn} Sw(1) ≥ k - 1/k. We show that for free pro-p groups, using the filtration given by its dimension subgroups, this is not true in general
Conjugacy in normal subgroups of hyperbolic groups
No full textLet N be a finitely generated normal subgroup of a Gromov hyperbolic group G. We establish criteria for N to have solvable conjugacy problem and be conjugacy separable in terms of the corresponding properties of G/N. We show that the hyperbolic group from F. Haglund's and D. Wise's version of Rips's construction is hereditarily conjugacy separable. We then use this construction to produce first examples of finitely generated and finitely presented conjugacy separable groups that contain non-(conjugacy separable) subgroups of finite index
The preparation of liposomes using compressed carbon dioxide
No full textEThOS - Electronic Theses Online ServiceGBUnited Kingdo
pH responsive liposome-in-microsphere formulations for drug delivery to the colon
No full textA formulation has been developed that incorporates sub micron liposomes in pH responsive polymer microspheres for drug delivery to the ileocaecal junction of the GI tract. Eudragit S100 microspheres were produced using a double emulsion technique and used to encapsulate liposomes. To withstand the solvent used within the microsphere production route, the liposomes were coated with chitosan. The model drug 5-ASA was incorporated into the liposomal formulations with release being explored in simulated GI tract conditions
Ultrasound Assisted Organic Synthesis in a Piphasic Supercritical CO₂ Water Reaction Medium
No full textInfect Control Hosp Epidemiol
No full textSurgical site infections (SSIs) are among the most common healthcare-associated infections in low- and middle-income countries. To encourage establishment of actionable and standardized SSI surveillance in these countries, we propose simplified surveillance case definitions. Here, we use NHSN reports to explore concordance of these simplified definitions to NHSN as 'reference standard.'CC999999/ImCDC/Intramural CDC HHSUnited States/2022-10-27T00:00:00Z32167439PMC960855712055vault:4344
Solubilities of Pharmaceutical Compounds in Ionic Liquids
No full textThe solubilities of paracetamol and ibuprofen were determined in two different ionic liquids at temperatures of 298.15 K, 308.15 K, 318.15 K, 328.15 K, and 338.15 K. The ionic liquids selected were 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF6] and 1-hexyl-3-methylimidazolium hexafluorophosphate [HMIM][PF6]. In addition, solubility data for paracetamol and ibuprofen in water are reported at the same temperatures extending the data commonly reported in pharmaceutical reference texts. For all solvents the concentration of drug in solution was determined by UV spectrophotometry
Weak commutativity and finiteness properties of groups
No full textWe consider the group X(G) obtained from G*G by forcing each element g in the first free factor to commute with the copy of g in the second free factor. Deceptively complicated finitely presented groups arise from this construction: X(G) is finitely presented if and only if G is finitely presented, but if F is a non-abelian free group of finite rank then X(F) has a subgroup of finite index whose third homology is not finitely generated511168180CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP303350/2013-02016/05678-3The first author was supported in part by a Wolfson Research Merit Award from the Royal Society. The second author was supported in part by regular grant 2016/05678‐3 from FAPESP and ‘bolsa de produtividade em pesquisa’ 303350/2013‐0 CNPq, Brazi
Global Aquaculture Performance Index (GAPI): The First Global Environmental Assessment of Marine Fish Farming
No full text“Sustainable” is among the most sought after of all seafood product adjectives. Ironically it is also one of the most poorly defined and understood. The Global Aquaculture Performance Index (GAPI) is the first tool to assess environmental performance of global marine aquaculture production, permitting direct comparison of disparate species, production methods and jurisdictions. Clear patterns emerge from this analysis; significant variation of environmental performance is driven by the species being farmed, significant room for improvement exists across the entire sector, the worst performing players are also the fastest growing, particularly within Asia, and perhaps most importantly, this work highlights the potential trap awaiting policy makers who focus too narrowly on farm production efficiency alone as a solution to diminishing seafood availability.This work was financially supported by the Lenfest Oceans Program and Pew Environmental Trusts and came to fruition through the dedication and leadership of Chris Mann and Rachel Hopkins. We recognize the EPI research group for initial inspiration of this work. We thank Katherine Bostick, Peter Bridson, Carrie Brownstein, Alice Chiu, Matthew Elliot, Rebecca Goldburg, George Leonard, Corey Peet, and Helene York for their many contributions to the development of the GAPI approach and resultant tool. We thank Vicki Blazer, Claude Boyd, Alejandro Bushmann, Alex de Sherbinin, Daniel Esty, Jennifer Ford, Christine Kim, Kevin Lafferty, Astrid Sholtz, Tanja Srebotnjak, Peter Tyedmers, and Judith Weis for their thoughtful contributions and advice in building criteria-specific assessment modules.FacultyReviewe
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