309 research outputs found
A Study of Runoff from Small Drainage Areas and the Openings in Attendant Drainage Structures
In 1926, John T. Lynch read to the Kentucky Academy of Sciences a paper entitled, The Relation Between Drainage Area and Waterway Required for Culverts and Small Bridges in Kentucky. The paper was based on a study of many small drainage structures then existing in the highway system, and a general evaluation of the performance of the structures in relation to rainfall and runoff from contributing watersheds.
As a result of this report, and in accordance with the suggestions contained in it, the Department of Highways adopted a system of runoff coefficients applicable to different sections of the state and usable in the empirical Talbot formula for computing the quantity of flow from a drainage area. This information was contained in the booklet of instructions for bridge and culvert surveys which has been in effect for almost 25 years
Scaling of the CKM Matrix in the 5D MSSM
We discuss a five-dimensional Minimal Supersymmetric Standard Model
compactified on a orbifold, looking at, in particular, the one-loop
evolution equations of the Yukawa couplings for the quark sector and various
flavor observables. Different possibilities for the matter fields are
discussed, that is, where they are in the bulk or localised to the brane. The
two possibilities give rise to quite different behaviours. By studying the
implications of the evolution with the renormalisation group of the Yukawa
couplings and of the flavor observables we find that, for a theory that is
valid up to the unification scale, the case where fields are localised to the
brane, with a large , would be more easily distinguishable from
other scenarios.Comment: 12 pages, 8 figures, Extra comments adde
Anti-communal, Anti-egalitarian, Anti-nurturing, Anti-loving: Sex and the 'Irredeemable' in Andrea Dworkin and Catharine MacKinnon
The work of Andrea Dworkin and Catharine A. MacKinnon on sex and sexuality has often been posed as adversary to the development of queer theory. Leo Bersani, in particular, is critical of the normative ambitions of their work, which he sees firstly as trying to âredeemâ sex acts themselves, and secondly as advocating for sexuality as a site of potential for social transformation. In this article, I argue that this is a misreading of their work. Drawing on Dworkin's wide body of writing, and MacKinnon early essays in Signs, I suggest that their work makes no such case for sex or sexuality. Rather, by bringing their analysis into conversation with Halberstam's recent work on âshadow feminismâ, I contend that Dworkin and MacKinnon's antisocial, anti-pastoral and distinctly anti-normative vision of sex and sexuality shares many of the same features of queer theory, ultimately advocating for sex as âirredeemableâ
A revised scheme for the reactivity of iron (oxyhydr)oxide minerals towards dissolved sulfide
The reaction between dissolved sulfide and synthetic iron (oxyhydr)oxide minerals was studied in artificial seawater and 0.1 M NaCl at pH 7.5 and 25°C. Electron transfer between surface-complexed sulfide and solid phase Fe(III) results in the oxidation of dissolved sulfide to elemental sulfur, and the subsequent dissolution of the surface-reduced Fe. Sulfide oxidation and Fe(II) dissolution kinetics were evaluated for freshly precipitated hydrous ferric oxide (HFO), lepidocrocite, goethite, magnetite, hematite, and Al-substituted lepidocrocite. Reaction kinetics were expressed in terms of an empirical rate equation of the form:
R-i = k(i)(H2S)(t=0)(0.5)A
where Ri is the rate of Fe(II) dissolution (RFe) or the rate of sulfide oxidation (RS), ki is the appropriate rate constant (kFe or kS), (H2S)t=0 is the initial dissolved sulfide concentration, and A is the initial mineral surface area. The rate constants derived from the above equation suggest that the reactivity of Fe (oxyhydr)oxide minerals varies over two orders of magnitude, with increasing reactivity in the order, goethite < hematite < magnetite << lepidocrocite â HFO. Competitive adsorption of major seawater solutes has little effect on reaction kinetics for the most reactive minerals, but results in rates which are reduced by 65-80% for goethite, magnetite, and hematite. This decrease in reaction rates likely arises from the blocking of surface sites for sulfide complexation by the adsorption of seawater solutes during the later, slower stages of adsorption (possibly attributable to diffusion into micropores or aggregates). The derivation of half lives for the sulfide-promoted reductive dissolution of Fe (oxyhydr)oxides in seawater, suggests that mineral reactivity can broadly be considered in terms of two mineral groups. Minerals with a lower degree of crystal order (hydrous ferric oxides and lepidocrocite) are reactive on a time-scale of minutes to hours. The more ordered minerals (goethite, magnetite, and hematite) are reactive on a time-scale of tens of days. Substitution of impurities within the mineral structure (as is likely in nature) has an effect on mineral reactivity. However, these effects are unlikely to have a significant impact on the relative reactivities of the two mineral groups
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Conserved community structure and simultaneous divergence events in the fig wasps associated with Ficus benjamina in Australia and China
Localised patterns of species diversity can be influenced by many factors, including regional species pools, biogeographic features and interspecific interactions. Despite recognition of these issues, we still know surprisingly little about how invertebrate biodiversity is structured across geographic scales. In particular, there have been few studies of how insect communities vary geographically while using the same plant host. We compared the composition (species, genera) and functional structure (guilds) of the chalcid wasp communities associated with the widespread fig tree, Ficus benjamina, towards the northern (Hainan province, China) and southern (Queensland, Australia) edges of its natural range. Sequence data were generated for nuclear and mtDNA markers and used to delimit species, and Bayesian divergence analyses were used to test patterns of community cohesion through evolutionary time. Both communities host at least 14 fig wasp species, but no species are shared across continents. Community composition is similar at the genus level, with six genera shared although some differ in species diversity between China and Australia; a further three genera occur in only China or Australia. Community functional structure remains very similar in terms of numbers of species in each ecological guild despite community composition differing a little (genera) or a lot (species), depending on taxonomic level. Bayesian clustering analyses favour a single community divergence event across continents over multiple events for different ecological guilds. Molecular dating estimates of lineage splits between nearest inter-continental species pairs are broadly consistent with a scenario of synchronous community divergence from a shared "ancestral community". Fig wasp community structure and genus-level composition are largely conserved in a wide geographic comparison between China and Australia. Moreover, dating analyses suggest that the functional community structure has remained stable for long periods during historic range expansions. This suggests that ecological interactions between species may play a persistent role in shaping these communities, in contrast to findings in some comparable temperate systems
Oxidative Status and Telomere Length Are Related to Somatic and Physiological Maturation in Chicks of European Starlings (Sturnus Vulgaris)
Telomere length can be considered as an indicator of an organism\u27s somatic state, long telomeres reflecting higher energy investment in self-maintenance. Early-life is a period of intense investment in somatic growth and in physiological maturation but how this is reflected in telomere length remains unclear. Using European starling chicks we tested: (i) how telomere length measured at asymptotic mass is related to proxies of somatic growth and physiological maturity in 17-day-old nestlings; (ii) how telomere length measured at 17â
days then predicts the changes in somatic and physiological maturity occurring in fledglings (between 17 and 21â
days); (iii) how growth and telomere length co-vary when chicks are under experimentally good (fed) growth conditions. Depending on environmental conditions, our data suggest links between somatic growth, physiological maturation and body maintenance parameters (positive with oxidative stress and negative with telomere length) in nestlings. Telomere length measured at day 17 predicted a subsequent change in physiological maturation variables observed in fledglings, but only in second-brood chicks: chicks with shorter telomeres had a higher pre-fledging rate of increase in haematocrit and haemoglobin content and a greater decrease in reticulocyte count. Finally, food supplementation of chicks did not change telomere length compared with that in control siblings. Our results suggest that physiological maturation prior to fledging may occur at the expense of telomere length but only when environmental conditions are sub-optimal
Selectivity of a thiosemicarbazonatocopper(II) complex towards duplex RNA. Relevant noncovalent interactions both in solid state and solution
Thiosemicarbazones and their metal derivatives have long been screened as antitumor agents, and their interactions with DNA have been analysed. Herein, we describe the synthesis and characterization of compounds containing [CuL]+ entities (HL = pyridine-2-carbaldehyde thiosemicarbazone) and adenine, cytosine or 9-methylguanine, and some of their corresponding nucleotides. For the first time, crystal structures of adenine- and 9-methylguanine-containing thiosemicarbazone complexes are reported. To the best of our knowledge, the first study on the affinity thiosemicarbazoneâRNA is also provided here. Experimental and computational studies have shown that [CuL(OH2)]+ entities at low concentration intercalate into dsRNA poly(rA)·poly(rU) through strong hydrogen bonds involving uracil residues and ÏâÏ stacking interactions. In fact, noncovalent interactions are present both in the solid state and in solution. This behaviour diverges from that observed with DNA duplexes and creates an optimistic outlook in achieving selective binding to RNA for subsequent possible medical applications.Obra Social âla Caixaâ
(OSLC-2012-007), Ministerio de EconomĂa y Competitividad
and FEDER funds (CTQ2013-48937-C2-1-P, CTQ2015-70371-
REDT, MAT2012-34740 and CTQ2014-58812-C2-2-R), Junta de
Castilla y LeĂłn (BU237U13), the Basque Government (IT-779-
13), Gerencia Regional de Salud, ConsejerĂa de Sanidad, Junta
de Castilla y LeĂłn (GRS 1023/A/14 and GR172)
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