Ocular aberrations in the peripheral visual field

We modified a commercial Hartmann-Shack aberrometer and used it to measure ocular aberrations across the central 42º horizontal x 32º vertical visual fields of five young emmetropic subjects. Some Zernike aberration coefficients show coefficient field distributions that were similar to the field dependence predicted by Seidel theory (astigmatism, oblique astigmatism, horizontal coma, vertical coma), but defocus did not demonstrate such similarity.

Specifying peripheral aberrations in visual science

Purpose: Investigations of foveal aberrations assume circular pupils. However, the pupil becomes increasingly elliptical with increase in visual field eccentricity. We address this and other issues concerning peripheral aberration specification. Methods: One approach uses an elliptical pupil similar to the actual pupil shape, stretched along its minor axis to become a circle so that Zernike circular aberration polynomials may be used. Another approach uses a circular pupil whose diameter matches either the larger or smaller dimension of the elliptical pupil. Pictorial presentation of aberrations, influence of wavelength on aberrations, sign differences between aberrations for fellow eyes, and referencing position to either the visual field or the retina are considered. Results: Examples show differences between the two approaches. Each has its advantages and disadvantages, but there are ways to compensate for most disadvantages. Two representations of data are pupil aberration maps at each position in the visual field and maps showing the variation in individual aberration coefficients across the field. Conclusions: Based on simplicity of use, adequacy of approximation, possible departures of off-axis pupils from ellipticity, and ease of understanding by clinicians, the circular pupil approach is preferable to the stretched elliptical approach for studies involving field angles up to 30 deg.

‘Wanna do more math’: engaging underachieving Indigenous learners the YuMi Deadly way.

The Accelerating Indigenous Mathematics (AIM) Program offered by the YuMi Deadly Centre from QUT accelerates the mathematics learning of underperforming students in Years 8 - 10 by a) apportioning Years 2-10 Australian Curriculum: Mathematics content into three years, and b) provides a teaching approach that accelerates the mathematical learning. The philosophy of the YuMi Deadly teaching approach for mathematics is one that requires a ‘body’, ‘hand’, ‘mind’ pedagogy. This presentation will provide examples of the “‘body’, ‘hand’, ‘mind’” mathematics pedagogy. In AIM classrooms, mathematics is presented this approach is having a positive impact. Students are willing ‘to have a go’ without shame; and they develop the desire to learn and improve their numeracy.

Rapid, long-distance dispersal by pumice rafting

Pumice is an extremely effective rafting agent that can dramatically increase the dispersal range of a variety of marine organisms and connect isolated shallow marine and coastal ecosystems. Here we report on a significant recent pumice rafting and long-distance dispersal event that occurred across the southwest Pacific following the 2006 explosive eruption of Home Reef Volcano in Tonga. We have constrained the trajectory, and rate, biomass and biodiversity of transfer, discovering more than 80 species and a substantial biomass underwent a .5000 km journey in 7–8 months. Differing microenvironmental conditions on the pumice, caused by relative stability of clasts at the sea surface, promoted diversity in biotic recruitment. Our findings emphasise pumice rafting as an important process facilitating the distribution of marine life, which have implications for colonisation processes and success, the management of sensitive marine environments, and invasive pest species.

Reversible cation/anion extraction from K2La2Ti3O10: Formation of new layered titanates, KLa2Ti3O9.5 and La2Ti3O9

A new soft-chemical transformation of layered perovskite oxides is described wherein K2O is sequentially extracted from the Ruddlesden-Popper (R-P) phase, K2La2Ti3O10 (I), yielding novel anion-deficient KLa2Ti3O9.5 (II) and La2Ti3O9 (III). The transformation occurs in topochemical reactions of the R-P phase I with PPh4Br and PBu4Br (Ph = phenyl; Bu = n-butyl). The mechanism involves the elimination of KBr accompanied by decomposition of PR4+ (R = phenyl or n-butyl) that extracts oxygen from the titanate. Analysis of the organic products of decomposition reveals formation of Ph3PO, Ph3P, and Ph-Ph for R = phenyl, and Bu3PO, Bu3P along with butane, butene, and octane for R = butyl. The inorganic oxides II and III crystallize in tetragonal structures (II: P4/mmm, a = 3.8335(1) angstrom, c = 14.334(1) angstrom; III: /4/ mmm, a = 3.8565(2) angstrom, c = 24.645(2) angstrom) that are related to the parent R-P phase. II is isotypic with the Dion-Jacobson phase, RbSr2Nb3O10, while III is a unique layered oxide consisting of charge-neutral La2Ti3O9 anion-deficient perovskite sheets stacked one over the other without interlayer cations. Interestingly, both II and III convert back to the parent R-P phase in a reaction with KNO3. While transformations of the R-P phases to other related layered/three-dimensional perovskite oxides in ion-exchange/metathesis/dehydration/reduction reactions are known, the simultaneous and reversible extraction of both cations and anions in the conversions K2La2Ti3O10 reversible arrow KLa2Ti3O9.5 reversible arrow La2Ti3O9 is reported here for the first time.

A[Bi3Ti4O13] and A[Bi3PbTi5O16] (A = K, Cs): New n=4 and n=5 members of the layered perovskite series, A[A ' n-1B nO3n+1], and their hydrates

We describe the synthesis and structural characterization of new layered bismuth titanates, A[Bi3Ti4O13] and A[Bi3PbTi5O16]for A = K, Cs, corresponding to n = 4 and 5 members of the Dion-Jacobson series of layered perovskites of the general formula, A[A'n-1BnO3n+1]. These materials have been prepared by solid state reaction of the constituents containing excess alkali, which is required to suppress the formation of competitive Aurivillius phases. Unlike the isostructural niobates and niobium titanates of the same series, the new phases reported here are spontaneously hydrated-a feature which could make them potentially useful as photocatalysts for water splitting reaction. On hydration of the potassium compounds, the c axis expands by ca. 2 Angstrom and loses its doubling [for example, the tetragonal lattice parameters of K[Bi3Ti4O13] and its dihydrate are respectively a = 3900(1)Angstrom c 37.57(2) Angstrom; a 3.885(1) Angstrom, c = 20.82(4) Angstrom]; surprisingly, the cesium analogues do not show a similar change on hydration.

O governo de Tibério e a difícil arte de suceder bons imperadores

Resumo: Neste artigo, propomo-nos a analisar o Governo do Imperador Romano Tibério, da forma como foi descrito por Dion Cássio Cocceiano na obra História Romana. Dion Cássio foi senador na passagem do II para o III século d.C. e sua narrativa nos chegou bastante fragmentada, reconstruída a partir dos excertos de Xifilino e Zonaras. A autoridade do Príncipe não era hereditária. Assim, tornavase necessário refazer os laços de patronato e amicitia no início de cada governo. E esta não era uma tarefa fácil, nem mesmo para Tibério que sucedeu o considerado bom Imperador Otávio Augusto.

Ground-water resources data of Charlotte, DeSoto, and Hardee Counties, Florida

Charlotte, De Soto, and Hardee counties are east-southeast of Tampa in west-central peninsular Florida, figure 1. In order to plan the future water-resource development of the area, information about the water resources is needed. To meet this need, the Water Resources Division of the U.S. Geological Survey, in cooperation with the Peace River Basin Board of the Southwest Florida Water Management District as part of the statewide cooperative program with the Division of Geology, Florida Board of Conservation, began a continuing hydrologic data collection program in July, 1963, as an initial step in the investigation and evaluation of the groundwater resources of Hardee and De Soto counties. A similar hydrologic data program commenced in Charlotte County in July, 1964. Previous work in Hardee and De Soto counties included a one year reconnaissance by the Division of Water Resources and Conservation, Florida Board of Conservation, which concluded in June, 1963, and resulted in a hydrologic report (Woodard, 1964). As an outgrowth of the hydrologic data program, a Map Series report portraying the chemical character of water in the Floridan aquifer in the southern Peace River basin was prepared in 1967 (Kaufman and Dion). The data contained herein constitute the basis for the Map Series report. Additional selected data, including records of wells and chemical analyses,, on the ground-water resources of the three county area are also included and are published to make the data available. (Document has 28 pages.)

加卸载响应比(Load/Unload Response Ratio)、能量加速释放(AE/MR)的临界区尺度及地震预测

加卸载响应比理论的主要思路是 :系统在稳定状态时加载响应与卸载响应的比值与非稳定状态时加载响应与卸载响应的比值是完全不同的。大震前加卸载响应比升高和能量加速释放这两种现象可以用来对地震进行中期预报。同时 ,加卸载响应比理论和能量加速释放可能有相同的物理机制。为了验证这种地震预报方法的可行性 ,我们研究了几例发生在澳大利亚与中国 ,M 5 0～ 7 9之间的地震 ,其中包括破坏严重的澳大利亚纽卡斯尔地震和中国的唐山地震。我们利用以震源中心一定范围内的数据计算了震前的加卸载响应比和能量加速释放的幂律拟合。能量幂律加速释放存在一组最佳的拟合 ,一定范围内加卸载响应比达最大值表明加卸载响应比也有一个临界区尺度。进一步讲 ,加卸载响应比与能量加速释放的临界区尺度是相似的。这些结果表明加卸载响应比与能量加速释放有相同的物理机制。进一步的研究可能会对这种物理机制提供更好的解释 ,同时也能对地震的中期预报提供理论基础

Objektu-komunztadura XIX eta XX. mendeetako euskal gramatiketan

Beatriz Fernández eta Pablo Albizu (arg.)

Banku erlazioaren eragina finantza bazterketan

Geroz eta lehiakorragoa den ingurune batean, finantza erakundeek beren bezeroekin duten harremanaren errentagarritasuna gutxiengo kostuaren bitartez bermatzen saiatzen dira. Hori dela eta, balio gehigarria sortzeko gai diren segmentuen aldeko bereizkeria positiboa sortzen da eta, era berean, merkatuak inposatzen dituen gutxiengo eskaerak betetzen ez dituzten taldeen nolabaiteko baztertzea. Ingurune honetan, geroz eta biztanle portzentai handiagoari eragiten dion “finantza bazterketa” deituriko arazoa sortzen da.

Relationship between fish size and otolith length for 63 species of fishes from the Eastern North Pacific Ocean

Otoliths commonly are used to determine the taxon, age, and size of fishes. This information is useful for population management, predator-prey studies, and archaeological research. The relationship between the length of a fish and the length of its otoliths remains unknown for many species of marine fishes in the Pacific Ocean. Therefore, the relationships between fish length and fish weight, and between otolith length and fish length, were developed for 63 species of fishes caught in the eastern North Pacific Ocean. We also summarized similar relationships for 46 eastern North Pacific fish species reported in the literature. The relationship between fish length and otolith length was linear, and most of the variability was explained by a simple least-squares regression (r 2 > 0.700 for 45 of 63 species). The relationship between otolith length and fish length was not significantly different between left and right otoliths for all but one fish species. Images of otoliths from 77 taxa are included to assist in the identification of species. (PDF file contains 38 pages.)

Gipuzkoako Surf Federazioaren 2015-2018 lau urtekorako plangintza estrategikoa

Gipuzkoako Surf Federazioari helburuak zehaztu eta bideak markatzen lagunduko dion lau urtekorako plan estrategikoa da.

Gizarte-elkarrekintza ingurunearen irakatsi eta ikasi prozesuan Lehen Hezkuntzan

Lan honetan, elkarrekintzaren bidez irakasle batek ikasleengan ezagutzak eraikitzeko zer mekanismoren bidez lortzen duen aztertu da, laguntzak nola egokitzen dituen eta laguntzeari nola uzten dion ikertuz. Helburua, elkarrekintzan eragina daukaten mekanismoak identifikatzea, deskribatzea eta ulertzea izan da. Horretarako, ikasleen iniziatiba bultzatzen duen giroan oinarritutako behaketa parte-hartzailea erabili da, errealitatea sistematikoki behatu eta eman diren gertaerak jaso, deskribatu, aztertu eta interpretatu direlarik. Behin transkribatutako saioak aztertuta, elkarrekintza segmentuak atera dira, horietan gehien errepikatzen diren jokabide-patroiak jasoz. Laguntzak egokitzean zein laguntzeari uztean, irakaslea ikasleen iniziatibetatik abiatzen dela ondorioztatu da.

Lehiaketa motor baten direkzio piparen diseinua

[EU]Hurrengo orrialdeetan aurkezten den proiektu honetan, lehiaketa motor baten direkzio piparen diseinua proposatzen da zeinak Moto Engineering Foundation fundazioak sustatutako nazioarteko Motostudent txapelketan parte hartzeko motorrera egokituta egon beharko den. Honako helburu honekin beraz, direkzio piparen diseinu egoki bat egin ahal izateko piezak sufrituko dituen karga egoerak aurreikusi beharko ditugu hauen arabera jasan beharreko tentsio egoerak aztertu ahal izateko. Piezaren tentsioen analisia aurrera eraman beharko da beraz, diseinaturiko piezaren funtzionamendu egokia ziurtatu ahal izateko. Historian zehar existitutako diseinu modelo ezberdinak eta baita gaur egunean gehien erabilitakoak ere aurkeztu eta gero, gure kasura hobekien moldatuko zaion adibidetik ekingo zaio diseinuari, aldez aurretik eskuratutako datu eta errodamenduetatik abiatuz. Horrenbestez, oinarritzat hartutako direkzio sistema modeloa eta bestelako elementuen neurriak datutzat hartuta, tija zein norabide ardatzarena esate baterako, direkzio piparen hasierako geometria definituko da. Eskuragarri ditugun analisi metodo ezberdinak aztertu eta gure kasura hobekien moldatzen dena aukeratu eta eraikitako piezari aplikatuko zaio. Lorturiko emaitzen arabera hasiera batean planteaturiko diseinua onartu edo baztertzea erabaki beharko dugu. Beraz, gure diseinua optimizatuz joateko aukera izango dugu, baldintzak eta betebeharrak egiztatuko dituen amaierako pieza diseinua lortu arte. Bukatzeko, proiektuari itxiera emango dion atala aurkeztuko da, hala nola, proiektuaren garapenean zehar lorturiko emaitzak eta ondorioak biltzen dituen atala non lorturiko direkzio piparen funtzionamendu egokia bermatzen dituzten parametroak aurkeztuko diren. Gainera, direkzio sistemaren funtsezko atala izango diren errodamenduen kalkulu eta aukeraketa bideratuko da baita ere.