2,886 research outputs found
Psychophysical evidence for two routes to suppression before binocular summation of signals in human vision
No full textVisual mechanisms in primary visual cortex are suppressed by the superposition of gratings perpendicular to their preferred orientations. A clear picture of this process is needed to (i) inform functional architecture of image-processing models, (ii) identify the pathways available to support binocular rivalry, and (iii) generally advance our understanding of early vision. Here we use monoptic sine-wave gratings and cross-orientation masking (XOM) to reveal two cross-oriented suppressive pathways in humans, both of which occur before full binocular summation of signals. One is a within-eye (ipsiocular) pathway that is spatially broadband, immune to contrast adaptation and has a suppressive weight that tends to decrease with stimulus duration. The other pathway operates between the eyes (interocular), is spatially tuned, desensitizes with contrast adaptation and has a suppressive weight that increases with stimulus duration. When cross-oriented masks are presented to both eyes, masking is enhanced or diminished for conditions in which either ipsiocular or interocular pathways dominate masking, respectively. We propose that ipsiocular suppression precedes the influence of interocular suppression and tentatively associate the two effects with the lateral geniculate nucleus (or retina) and the visual cortex respectively. The interocular route is a good candidate for the initial pathway involved in binocular rivalry and predicts that interocular cross-orientation suppression should be found in cortical cells with predominantly ipsiocular drive
Binocular interaction: contrast matching and contrast discrimination are predicted by the same model
No full textHow do signals from the 2 eyes combine and interact? Our recent work has challenged earlier schemes in which monocular contrast signals are subject to square-law transduction followed by summation across eyes and binocular gain control. Much more successful was a new ‘two-stage’ model in which the initial transducer was almost linear and contrast gain control occurred both pre- and post binocular summation. Here we extend that work by: (i) exploring the two-dimensional stimulus space (defined by left- and right-eye contrasts) more thoroughly, and (ii) performing contrast discrimination and contrast matching tasks for the same stimuli. Twenty-five base-stimuli made from 1 c/deg patches of horizontal grating, were defined by the factorial combination of 5 contrasts for the left eye (0.3-32%) with five contrasts for the right eye (0.3-32%). Other than in contrast, the gratings in the two eyes were identical. In a 2IFC discrimination task, the base-stimuli were masks (pedestals), where the contrast increment was presented to one eye only. In a matching task, the base-stimuli were standards to which observers matched the contrast of either a monocular or binocular test grating. In the model, discrimination depends on the local gradient of the observer’s internal contrast-response function, while matching equates the magnitude (rather than gradient) of response to the test and standard. With all model parameters fixed by previous work, the two-stage model successfully predicted both the discrimination and the matching data and was much more successful than linear or quadratic binocular summation models. These results show that performance measures and perception (contrast discrimination and contrast matching) can be understood in the same theoretical framework for binocular contrast vision
Accelerated norm-optimal iterative learning control
No full textThis paper proposes a novel technique for accelerating the convergence of the previously published norm-optimal iterative learning control (NOILC) methodology. The basis of the results is a formal proof of an observation made by the first author, namely that the NOILC algorithm is equivalent to a successive projection algorithm between linear varieties in a suitable product Hilbert space. This leads to two proposed accelerated algorithms together with well-defined convergence properties. The results show that the proposed accelerated algorithms are capable of ensuring monotonic error norm reductions and can outperform NOILC by more rapid reductions in error norm from iteration to iteration. In particular, examples indicate that the approach can improve the performance of NOILC for the problematic case of non-minimum phase systems. Realisation of the algorithms is discussed and numerical simulations are provided for comparative purposes and to demonstrate the numerical performance and effectiveness of the proposed methods
Contrast masking in strabismic amblyopia: attenuation, noise, interocular suppression and binocular summation
No full textTo investigate amblyopic contrast vision at threshold and above we performed pedestal-masking (contrast discrimination) experiments with a group of eight strabismic amblyopes using horizontal sinusoidal gratings (mainly 3 c/deg) in monocular, binocular and dichoptic configurations balanced across eye (i.e. five conditions). With some exceptions in some observers, the four main results were as follows. (1) For the monocular and dichoptic conditions, sensitivity was less in the amblyopic eye than in the good eye at all mask contrasts. (2) Binocular and monocular dipper functions superimposed in the good eye. (3) Monocular masking functions had a normal dipper shape in the good eye, but facilitation was diminished in the amblyopic eye. (4) A less consistent result was normal facilitation in dichoptic masking when testing the good eye, but a loss of this when testing the amblyopic eye. This pattern of amblyopic results was replicated in a normal observer by placing a neutral density filter in front of one eye. The two-stage model of binocular contrast gain control [Meese, T.S., Georgeson, M.A. & Baker, D.H. (2006). Binocular contrast vision at and above threshold. Journal of Vision 6, 1224–1243.] was ‘lesioned’ in several ways to assess the form of the amblyopic deficit. The most successful model involves attenuation of signal and an increase in noise in the amblyopic eye, and intact stages of interocular suppression and binocular summation. This implies a behavioural influence from monocular noise in the amblyopic visual system as well as in normal observers with an ND filter over one eye
Bioavailability of nutrients for animals : amino acids, minerals, and vitamins /
No full textThis practical book provides crucial information necessary to formulate diets with appropriate amounts of amino acids, minerals, and vitamins. The factors that influence how well animals obtain these critical nutrients and methods for determining bioavailability are reviewed in this comprehensive text. In addition, data from both ruminants and nonruminants are included as well as established estimates of bioavailability for particular feed stuffs and feed supplements.This practical book provides crucial information necessary to formulate diets with appropriate amounts of amino acids, minerals, and vitamins. The factors that influence how well animals obtain these critical nutrients and methods for determining bioavailability are reviewed in this comprehensive text. In addition, data from both ruminants and nonruminants are included as well as established estimates of bioavailability for particular feed stuffs and feed supplements.Foreword. -- Preface. -- Introduction. -- R.C. Littell, A.J. Lewis, and P.R. Henry, Statistical Evaluation of Bioavailability Assays. -- A.J. Lewis and H.S. Bayley, Amino Acid Bioavailability. -- A.J. Lewis and D.H. Baker, Bioavailability of D-Amino Acids and DL-Hydroxy Methionine. -- C.B. Ammerman, Methods for Estimation of Mineral Bioavailability. -- J.H. Soares, Jr., Calcium Bioavailability. -- P.R. Henry, Cobalt Bioavailability. -- D.H. Baker and C.B. Ammerman, Copper Bioavailability. -- E.R. Miller and C.B. Ammerman, Iodine Bioavailability. -- P.R. Henry and E.R. Miller, Iron Bioavailability. -- P.R. Henry and S.D. Benz, Magnesium Bioavailability. -- P.R. Henry, Manganese Bioavailability. -- J.H. Soares, Jr., Phosphorus Bioavailability. -- E.R. Miller, Potassium Bioavailability. -- P.R. Henry and C.B. Ammeman, Selenium Bioavailability. -- P.R. Henry, Sodium and Chlorine Bioavailability. -- P.R. Henry and C.B. Ammerman, Sulfur Bioavailability. -- D.H. Baker and C.B. Ammerman, Zinc Bioavailability. -- D.H. Baker, Vitamin Bioavailability. -- Appendix. -- Subject Index.Includes bibliographical references and index.Print version record.Elsevie
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The Life and Work of D.H. Hyers, 1913-1997
No full textThe following is a sketch of the life and work of Donald Holmes Hyers, Professor Emeritus from the University of Southern California. The theorem put forth by Hyers in 1941 concerning linear functional equations has gained a great deal of interest over the past two decades. Hundreds of articles have been written citing his works, many of which have furthered the theorem. This paper contains a brief description of Hyers’ theorem, a biographical essay and an extensive bibliography of Hyers’ work and works citing the Hyers theorem or the D.H. Hyers–S.M. Ulam–Th.M. Rassias theorem or related subjects of almost the last three decades. The author of this paper is the grandson of D.H. Hyers
Orasema lasallei Heraty & Baker 2020, sp. nov.
No full textOrasema lasallei sp. nov. (lasallei species group) (Figures 1, 2, 3a – d) http://zoobank.org/ urn:lsid:zoobank.org:act: DFB5A4A8-6CC0-4C1F-8B5309B8A062C652 Diagnosis This species is recognised by the antenna with 8 funiculars, basal area and speculum of fore wing bare, basal third of hind wing with sparse microsetae, face generally smooth but with the frons vertically costate, labrum with 6 – 11 marginal digits (Figure 3a,b), clypeus slightly rounded and projecting ventrally and with a distinct anteclypeus. As well, the head and mesosoma are blue green to darkly violaceous, the scape and legs yellow, and the gaster yellowish-brown with dark brown maculations dorsally. Of the specimens where it could be observed, the variation in labral digits ranged from 6 (1 specimen), 7 (5), 8 (7), 9 (5), 10 (3), to 11 (1). Female. Length 3.1 – 4.9 mm. Colour: Head and mesosoma blue green, metallic green, or darkly violaceous. Scape yellow; pedicel and anellus yellowish-brown; flagellum dark brown. Mandible yellowishbrown with dark brown margins and teeth; maxilla and labium yellow to pale brown. Coxae same colour as body or dark metallic purple. Fore wing hyaline; venation yellowish to pale brown. Petiole same as mesosoma; gaster yellowish-brown, Mt 1 brown with posterior band of yellow, remaining tergites yellow with dorsal brown band. Head in frontal view subtriangular; 1.1 – 1.3× as broad as high; face fairly smooth, frons vertically costate and setose, lower face adjacent to clypeus smooth and setose (Figure 3a); scrobal depression deep, laterally rounded, with transverse carinae and a vertical median ridge; dorsal scrobal depressions absent; eyes bare, inter-ocular distance 1.4 – 1.8× eye height; malar space 0.7 – 0.9× eye height; supraclypeal area slightly longer than broad, smooth with weak sculpture along lateral margins; clypeus fairly smooth with short setae; epistomal sulcus vaguely defined and shallowly impressed; anterior tentorial pit strongly impressed; anteclypeus present, ventral margin of clypeus slightly rounded. Labrum with 6 – 11 digits. Mandibular formula 3:2 or 3:3. Palpal formula 3:3. Occiput aciculate, shallowly emarginate in dorsal view, dorsal margin abrupt; temples broad. Scape not reaching median ocellus. Pedicel small and globose. Flagellum with 8 funiculars; flagellum length 1.3 1.4 × head height; F2 broader than pedicel, 1.5 – 2.6× as long as broad, 1.1 – 1.2× as long as F3; following funiculars subequal in length, equal in width; clava subconical. Mesosoma 1.0 – 1.3× as long as high. Mesoscutal midlobe rugose-reticulate to rugoseareolate, bare; lateral lobe coarsely rugose-areolate for the most part; notauli deep. Axilla rugose-areolate, dorsally rounded, on roughly same plane as scutellum; scutoscutellar sulcus broad, regularly foveate, reaching transscutal articulation medially; scutellar disc as long as or slightly longer than broad, mesoscutellar disc coarsely rugose-areolate; frenal line irregularly foveate; frenum rugose-areolate; axillular sulcus absent to very weakly margined; axillula strongly rugose-areolate. Propodeal disc broadly rounded, without depression or carina; shallowly areolate; callus rugose, with a few small setae; callar nib present or absent. Prepectus triangular dorsally, strongly narrowed ventrally, sculpture rugose. Mesepisternum areolate laterally, smooth ventrally, broadly rounded anterior to mid coxa. Upper mesepimeron smooth and weakly costate to costate; lower mesepimeron costate; transepimeral sulcus weakly impressed. Metepisternum laterally nearly smooth. Propleuron convex, weakly reticulate. Postpectal carina weak. Hind coxa 1.4 – 1.9× as long as broad, weakly reticulate dorsally, becoming smooth ventrally; hind femur 4.7 – 6.3× as long as broad, with short, dense setae apically; hind tibia densely setose. Fore wing 2.5 – 2.7× as long as broad, 2.6 – 2.7× as long as mesothorax; basal cell and speculum bare, costal cell and wing disc densely setose; marginal fringe relatively long; submarginal vein with small setae; marginal vein with dense short setae; stigmal vein 1.4 – 3.0× as long as broad, slightly angled; uncus weak and blunt; stigma with 3 sensilla in a straight line; postmarginal vein 1.3 – 3.6× as long as stigmal vein. Hind wing pilose apically, basal third microsetose but appearing bare, costal cell mostly bare except for several setae in extreme apex. Metasoma: Petiole cylindrical, linear in profile, 2.1 – 3.3× as long as broad, 1.1 – 1.4× as long as hind coxa, rugose-areolate, anterior carina strong, lateral margin rounded, ventral sulcus absent. Antecostal sulcus crossed by minute carinae; acrosternite posteriorly rounded to weakly angulate; apical setae of hypopygium with four long hairs clustered on each side of midline. Ovipositor slightly curved cephalad; subapical carina weak; first (ventral) valvula with 3 – 4 strong, widely separated teeth, second (dorsal) valvula with 6 – 7 annuli that are broadly separated. Male. Length 3.46 mm. Head width 1.2× head height; scape yellow; flagellum with 8 funiculars, clava 2-segmented, flagellum length 1.2× head height, anellus minute, difficult to distinguish, F2 2.6× as long as broad, hind femur yellow; petiole 10× as long as broad, 2.9× as long as hind coxa. Ant Host: Two teneral adults (wings in process of unfolding) taken from nest of Pheidole vorax (Fabr.) (Myrmicinae). DNA Matrix Name (Baker et al. 2020): Orasema _nsp_ ” dus ” _CRI_D4715. Phylogenetic Position (Baker et al. 2020): This species has variable placement in different analyses: as sister group to the susanae group in the Anchored Hybrid Enrichment (AHE) results (348 loci) or the combined Sanger and AHE results; or as sister to the straminiepes group in the Sanger Sequencing results. In all results, it is placed as a unique branch and is never included within any of the other species groups. Notably, it never groups with the festiva species group, which also have numerous digits on the labrum, suggesting that the multidigitate labrum, versus 4-digitate labrum, arose at least three times within Orasema. Holotype: Costa Rica: Guanacaste : Santa Rosa Nat. Pk., 300 m, 10°53 ʹ 33”N, 85°45 ʹ 59”W , 1 – 22.vi.1985, D.H. Janzen & I.D. Gauld [1♀, UCRCENT00161412], deposited in CNC. Paratypes: Costa Rica: Alajuela : 5 km W San Ramon, 1200 m, 10°05 ʹ 14”N, 84°30 ʹ 49”W vii.1997, O. Castro & P. Hanson [1♀, MUCR: UCRCENT00479322]. Guanacaste: P. N. Santa Rosa, 200 m, 10°53 ʹ N, 85°45 ʹ W , 24.v-14.vi.1986, P. Hanson [2♀, MUCR: UCRCENT00479339 40]. Santa Rosa Nat. Pk., 300 m, 10°53 ʹ 33”N, 85°45 ʹ 59”W , 11.v-1.vi.1985, D.H. Janzen, I.D. Gauld [1♂ 2♀, UCRC: UCRCENT00408492, UCRCENT00408494, UCRCENT00414048]. Santa Rosa Nat. Pk., 300 m, 10°53 ʹ 33”N, 85°45 ʹ 59”W , 13.vii-3.viii.1985, D.H. Janzen & I.D. Gauld [1♀, UCRC: UCRCENT00408493]. Santa Rosa Nat. Pk., 300 m, 10°53 ʹ 33”N, 85°45 ʹ 59”W , 22.vi13.vii.1985, D.H. Janzen & I.D. Gauld [1♀, UCRC: UCRCENT00408491]. Santa Rosa NP Hacienda, 300 m, 10°53 ʹ 33”N, 85°45 ʹ 59”W , 29.v.1978, 6.vi.1978, D. H. Janzen, dry hill [3♀, UMNH: UCRCENT00476435]. Limon: Hitoy Cerere Biological Reserve, 150 m, 9°40 ʹ 03 ” N, 83° 01 ʹ 47 ” W, 13.vi.2015, M. Branstetter, along stream, trop. rainforest, reared Pheidole vorax nest MGB2656 [2♀, UCRC: UCRCENT00446848 (D4715), UCRC: UCRCENT00455978]. San Jose: Ciudad Colón, 800 m, 9°54 ʹ 33”N, 84°14 ʹ 31”W , vi – vii.1990, Luis Fournier [1♀, USNM: UCRCENT00161411]. San Antonio de Escazu, 1300 m, 9°53 ʹ 00”N, 84°08 ʹ 00”W , 5.vi.1989, P. Hanson [1♀, UCRC: UCRCENT00408495]. El Salvador: 3 mi. W Quezaltepeque, 500 m, 13°49 ʹ 01”N, 89°18 ʹ 29”W , 23.vi.1961, M.E. Irwin [1♀, UCDC: UCRCENT00477843]. Honduras: Olancho : Catacamas, 15°50 ʹ 00 ” N, 85°51 ʹ 00 ” W, viii.1995, R. Cave, lowland gallery forest, Malaise Trap [1♀, MZLU: UCRCENT00242606]. Mexico: Chiapas : 1 mi S Rayon, 1280 m, 17° 11 ʹ 25”N, 93°00 ʹ 0”W , 16 June 1965, Burks, Meyer, Shaffner [5♀, deposited in TAMU: UCRCENT00243140, UCRCENT00243142 – 44, UCRC: UCRCENT00161424]. Veracruz: Orizaba, 1240 m, 18°50 ʹ 43”N, 97°06 ʹ 14”W , 3. [2♀, MHNG: UCRCENT00412228 – 29]. Nicaragua: Boaco : Camoapa, 500 m, 12°22 ʹ 00”N, 85°30 ʹ 00”W , xii.1976, W. H. Cross, door yard Gossypium hirsutum, swp [1♀, MEM: UCRCENT00242503]. Other material examined Costa Rica: San Jose : San Jose, 1150 m, 9°55 ʹ 00”N, 84°04 ʹ 00”W , M. Valerio [3♀, USNM: UCRCENT00416718 – 19]. Etymology. Named after John La Salle of the Australian National Insect Collection for his amazing work in Chalcidoidea and the Atlas of Living Australia.Published as part of Heraty, John M. & Baker, Austin J., 2020, New species of Orasema (Hymenoptera: Eucharitidae) from Central and South America, pp. 735-754 in Journal of Natural History 54 (9) on pages 738-742, DOI: 10.1080/00222933.2020.1747651, http://zenodo.org/record/429052
The treatment of Italy and Italians in D.H. Lawrence's writings
No full textThis thesis was scanned from the print manuscript for digital preservation and is copyright the author.
Researchers can access this thesis by asking their local university, institution or public library to
make a request on their behalf. Monash staff and postgraduate students can use the link in the References field
Environmental (waste) compliance control systems for UK SMEs
No full textWhile the ‘environment’ is often perceived as a heavily regulated area of business, in reality, directly-regulated businesses represent a small proportion of the business community. This study aimed to evaluate and outline potential improvements to compliance controls for small and medium-sized enterprises (SMEs), particularly those involved in the waste sector. Forty-four SMEs from England were interviewed/audited between April-September 2008. Using a UK-based system as a case-in-point, the Environment Agency’s (EA) Operational Risk Appraisal (‘Opra’)/Compliance Assessment Report (CAR) system was analysed. Environmental compliance performance indicators and an initial assessment methodology for SMEs were developed. The study showed:• Compliance with permitting legislation was poor in many areas.• Regulatory authorities are either unable/failing to implement their enforcement policies or unable/failing to identify non-compliances due to the infrequency or limited nature of their inspections.• Improvements are needed to the EA Opra/CAR system – control measures are not fully taken into account when calculating risk.Recommendations to improve SME compliance controls include using internationally applicable general and specific compliance and non-compliance performance indicators, re-designing the Opra system and using an initial assessment methodology based on understanding the hazardousness of SME categories, compliance levels and operator competency.<br/
The Importance Of Sex In Marriage Reflected In D.H. Lawrence’s Lady Chatterley’s Lover Novel (1928): A Psychoanalytic Perspective
No full textThis study is about the importance of sex in marriage in Lady Chatterley’s Lover. The objectives of the study are conducted to identify the indicators of the need for sex of the major character, to describe the major character attempt to meet the need, and to reveal the underlying reason of why the major character did viewed from the psychoanalytic perspective. The object of the study is Lady Chatterley’s Lover by D.H. Lawrence. It used psychoanalytic perspective. This research is a descriptive qualitative research. The type of data in this study is a text that consists of words, phrases and sentences. There are two data sources in this study. The primary data source is Lady
Chatterley’s Lover by D.H. Lawrence. The secondary data source consists of the other data, which have a relationship with the study, such as some biography of
the author, and other relevant information. The result of the study shows the following conclusions. First, based on the structural analysis the author wants to deliver a message that the meeting of sexual need is important in marriage. Second, based on the psychoanalytic perspective, it clear that in this novel D.H. Lawrence describes psychological phenomena in which one is seeking for the sexual satisfaction from a person other than one‟s spouse
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