Comparison of two methods (visual estimates and filming) for counts of horn flies (Haematobia irritans irritans) (L.) (Diptera : Muscidae)

Visual estimates are generally used for counts of horn flies, Haematobia irritans (L.) and play an important role as an instrument to quantify fly populations in scientific studies. In this study, horn fly counts were performed on 30 Nelore steers in the municipality of Aracatuba, SP Brazil, from January to December 1998. Flies were counted weekly by two methods: the estimate method whereby estimates of the number of flies on one side of the animal are obtained by visual observation, and the filming method whereby images of flies from both sides of the animal are recorded with a video camera. The tape was then played on a videotape recorder coupled to a television and the flies were counted on the screen. Both methods showed variations in horn fly population density during the period studied. However, significant differences (p < 0.05) were observed between the two methods with the filming method permitting the visualization of a larger number of flies than the estimate method. In addition, the filming method permitted safe and reliable counts hours after the images were taken, with the advantage that the tape can serve as an archive for random re-counts. (C) 2002 Elsevier B.V. B.V. All rights reserved.

(Table 2) Abundance of the main groups of planktonic animals in the 250-900 m water layer at the Broken Spur and Lost City sites according to visual counts from the Mir manned submersibles in 2002 and 2005

Three dives of the Mir manned submersibles with plankton counts and two vertical plankton hauls with a BR net were carried out above the Lost City (Atlantis underwater massif) and the Broken Spur hydrothermal fields during cruise 50 of R/V Akademik Mstislav Keldysh. Above the Atlantis seamount no significant increase in plankton concentration was found. Above the Lost City field horizontal heterogeneity of plankton distribution in the near-bottom layer and in overlying water layers was shown. Near-bottom aggregations of euphausiids and amphipods previously reported by other scientists seem to be related to attraction of these animals by the submersible's headlights rather than represent a natural phenomenon.

POPULATION DENSITY OF THE HELMETED CURASSOW (PAUXI PAUXI) IN TAMA NATIONAL PARK, COLOMBIA

We estimated the population density of the Helmeted Curassow (Pauxi pauxi) in Tama National Park (TNP) Colombia, using visual counts between December 2006 and December 2008. We used six line transects (1 km each) equitably distributed in a natural forest between 800 and 1,200 m asl in the southern part of the park. The sampling effort was 588 hrs with a total distance of 490 km, a detection rate of 0.06 records/hr, and an encounter rate of 0.08 individuals/km. Only solitary individuals were recorded (n = 40); the estimated density was 4.8 individuals/km(2). Most detections occurred in the lower strata of the forest (floor and sub-canopy) where hunters take advantage of curassows in the lower strata for successful harvest. The southern sector of TNP becomes important in the dry season. Our study suggests a large population is in TNP, but harvesting activities including removal of eggs, chicks, and juveniles, and hunting adults are affecting the reproductive rate and population of the species. Received 6 June 2011. Accepted 2 February 2012.

Estimation of axon counts in a rat model of glaucoma: comparison of fixed-pattern sampling with targeted sampling

Full axon counting of optic nerve cross-sections represents the most accurate method to quantify axonal damage, but such analysis is very labour intensive. Recently, a new method has been developed, termed targeted sampling, which combines the salient features of a grading scheme with axon counting. Preliminary findings revealed the method compared favourably with random sampling. The aim of the current study was to advance our understanding of the effect of sampling patterns on axon counts by comparing estimated axon counts from targeted sampling with those obtained from fixed-pattern sampling in a large collection of optic nerves with different severities of axonal injury.

Planeamento espacial marinho das áreas marinhas protegidas: o caso de estudo da ára protegida de gestão de recursos: Caloura - ilhéu de Vila Franca do Campo

Tese de Doutoramento, Ciências do Mar (Ecologia Marinha), 26 de Novembro de 2013, Universidade dos Açores.

Uma proposta de inovação no cardápio escolar baseada na avaliação do programa de alimentação escolar de Piracicaba-SP

Pós-graduação em Alimentos e Nutrição - FCFAR

Abundance and biomass of zooplankton collected in 1995 and 1998 in the frontal zone between the Gulf Stream and the Labrador current

Vertical distribution of meso- and macroplankton was studied in the region of the most sharply pronounced climatic frontal zone between the Gulf Stream and the Labrador current. Hauls with a plankton net BR 113/140 and visual counts of macroplankton from the Mir submersible were used. In the frontal zone a contact occurs between arctic-boreal communities and communities of the North Atlantic subtropical gyre. The community of the North Atlantic subtropical gyre is more mature in terms of succession; many macroplanktonic carnivores-scavengers (mainly shrimps Acanthephyra) develop there and form a ''living network'' feeding on those transported from the north rich arctic-boreal mesoplankton. As a result biomass of shrimps appears to be significantly higher than biomass of their preys. Peculiarities of vertical distribution and population structure of shrimps were analyzed. Data on quantitative vertical distribution of total biomass of meso- and macroplankton and its principal groups, including gelatinous animals (ctenophores, medusas, and siphonophores) were obtained. Variations of the role of different plankton groups with depth were considered; these data enable a conclusion that frontal variations of the community structure embrace the depth range from the surface down to 2000 m.

Composite stratigraphy of ODP Site 177-1094 and sediment core TTN057-13-PC4 (Table 1)

Visual counts of ice-rafted debris (IRD), foraminifera, and radiolaria were made for ~1500 samples in Site 1094 spanning the last four climatic cycles (marine isotope stages 1-11). Most, but not all, of the IRD variability is captured by whole-core physical properties including magnetic susceptibility and Q-ray attenuation bulk density. Glacial periods are marked by high IRD abundance and millennial-scale variability, which may reflect instability of ice shelves in the Weddell Sea region. Each interglacial period exhibits low IRD and high foraminiferal abundance during the early part of the interglacial, indicating relatively warm sea-surface temperatures and reduced influence of sea ice. IRD increases and foraminiferal abundances decrease during the latter part of each interglacial, indicating a return to more glacial-like conditions. Glacial terminations I and V are each characterized by a step-wise reduction in ice-rafting punctuated by a brief pulse in IRD delivery and reversal in delta18O. The coarse fraction of the sediment is dominated by ash and radiolaria, and the relative abundance of these components is remarkably similar to the concentration of Na+ in Vostok. Each of these variables is believed to be controlled mainly by sea-ice cover, thereby providing a means for sediment-ice core correlation.

Slow-phase onset influence on waveform identification and foveation time measure in congenital nystagmus

Congenital nystagmus (CN) is an ocular-motor disorder characterised by involuntary, conjugated ocular oscillations and its pathogenesis is still under investigation. This kind of nystagmus is termed congenital (or infantile) since it could be present at birth or it can arise in the first months of life. Most of CN patients show a considerable decrease of their visual acuity: image fixation on the retina is disturbed by nystagmus continuous oscillations, mainly horizontal. However, the image of a given target can still be stable during short periods in which eye velocity slows down while the target image is placed onto the fovea (called foveation intervals). To quantify the extent of nystagmus, eye movement recording are routinely employed, allowing physicians to extract and analyse nystagmus main features such as waveform shape, amplitude and frequency. Using eye movement recording, it is also possible to compute estimated visual acuity predictors: analytical functions which estimates expected visual acuity using signal features such as foveation time and foveation position variability. Use of those functions extend the information from typical visual acuity measurement (e.g. Landolt C test) and could be a support for therapy planning or monitoring. This study focuses on detection of CN patients' waveform type and on foveation time measure. Specifically, it proposes a robust method to recognize cycles corresponding to the specific CN waveform in the eye movement pattern and, for those cycles, evaluate the exact signal tracts in which a subject foveates. About 40 eyemovement recordings, either infrared-oculographic or electrooculographic, were acquired from 16 CN subjects. Results suggest that the use of an adaptive threshold applied to the eye velocity signal could improve the estimation of slow phase start point. This can enhance foveation time computing and reduce influence of repositioning saccades and data noise on the waveform type identification.

Eye movement analysis in congenital nystagmus:concise parameters estimation

Along with other diseases that can affect binocular vision, reducing the visual quality of a subject, Congenital Nystagmus (CN) is of peculiar interest. CN is an ocular-motor disorder characterized by involuntary, conjugated ocular oscillations and, while identified more than forty years ago, its pathogenesis is still under investigation. This kind of nystagmus is termed congenital (or infantile) since it could be present at birth or it can arise in the first months of life. The majority of CN patients show a considerable decrease of their visual acuity: image fixation on the retina is disturbed by nystagmus continuous oscillations, mainly horizontal. However, the image of a given target can still be stable during short periods in which eye velocity slows down while the target image is placed onto the fovea (called foveation intervals). To quantify the extent of nystagmus, eye movement recordings are routinely employed, allowing physicians to extract and analyze nystagmus main features such as waveform shape, amplitude and frequency. Use of eye movement recording, opportunely processed, allows computing "estimated visual acuity" predictors, which are analytical functions that estimate expected visual acuity using signal features such as foveation time and foveation position variability. Hence, it is fundamental to develop robust and accurate methods to measure both those parameters in order to obtain reliable values from the predictors. In this chapter the current methods to record eye movements in subjects with congenital nystagmus will be discussed and the present techniques to accurately compute foveation time and eye position will be presented. This study aims to disclose new methodologies in congenital nystagmus eye movements analysis, in order to identify nystagmus cycles and to evaluate foveation time, reducing the influence of repositioning saccades and data noise on the critical parameters of the estimation functions. Use of those functions extends the information acquired with typical visual acuity measurement (e.g., Landolt C test) and could be a support for treatment planning or therapy monitoring. © 2010 by Nova Science Publishers, Inc. All rights reserved.

Foveation time measure in Congenital Nystagmus through second order approximation of the slow phases

Congenital Nystagmus (CN) is an ocular-motor disorder characterised by involuntary, conjugated ocular oscillations, and its pathogenesis is still unknown. The pathology is de fined as "congenital" from the onset time of its arise which could be at birth or in the first months of life. Visual acuity in CN subjects is often diminished due to nystagmus continuous oscillations, mainly on the horizontal plane, which disturb image fixation on the retina. However, during short periods in which eye velocity slows down while the target image is placed onto the fovea (called foveation intervals) the image of a given target can still be stable, allowing a subject to reach a higher visual acuity. In CN subjects, visual acuity is usually assessed both using typical measurement techniques (e.g. Landolt C test) and with eye movement recording in different gaze positions. The offline study of eye movement recordings allows physicians to analyse nystagmus main features such as waveform shape, amplitude and frequency and to compute estimated visual acuity predictors. This analytical functions estimates the best corrected visual acuity using foveation time and foveation position variability, hence a reliable estimation of this two parameters is a fundamental factor in assessing visual acuity. This work aims to enhance the foveation time estimation in CN eye movement recording, computing a second order approximation of the slow phase components of nystag-mus oscillations. About 19 infraredoculographic eye-movement recordings from 10 CN subjects were acquired and the visual acuity assessed with an acuity predictor was compared to the one measured in primary position. Results suggest that visual acuity measurements based on foveation time estimation obtained from interpolated data are closer to value obtained during Landolt C tests. © 2010 IEEE.

Detection of foveation windows and analysis of foveation sequences in congenital nystagmus

Congenital nystagmus (CN) is an ocular-motor disorder characterised by involuntary, conjugated ocular oscillations, that can arise since the first months of life. Pathogenesis of congenital nystagmus is still under investigation. In general, CN patients show a considerable decrease of their visual acuity: image fixation on the retina is disturbed by nystagmus continuous oscillations, mainly horizontal. However, image stabilisation is still achieved during the short periods in which eye velocity slows down while the target image is placed onto the fovea (called foveation intervals). To quantify the extent of nystagmus, eye movement recording are routinely employed, allowing physicians to extract and analyse nystagmus main features such as shape, amplitude and frequency. Using eye movement recording, it is also possible to compute estimated visual acuity predictors: analytical functions which estimates expected visual acuity using signal features such as foveation time and foveation position variability. Use of those functions add information to typical visual acuity measurement (e.g. Landolt C test) and could be a support for therapy planning or monitoring. This study focus on robust detection of CN patients' foveations. Specifically, it proposes a method to recognize the exact signal tracts in which a subject foveates, This paper also analyses foveation sequences. About 50 eyemovement recordings, either infrared-oculographic or electrooculographic, from different CN subjects were acquired. Results suggest that an exponential interpolation for the slow phases of nystagmus could improve foveation time computing and reduce influence of breaking saccades and data noise. Moreover a concise description of foveation sequence variability can be achieved using non-fitting splines. © 2009 Springer Berlin Heidelberg.

Chromatic spatial contrast sensitivity estimated by visual evoked cortical potential and psychophysics

The purpose of the present study was to measure contrast sensitivity to equiluminant gratings using steady-state visual evoked cortical potential (ssVECP) and psychophysics. Six healthy volunteers were evaluated with ssVECPs and psychophysics. The visual stimuli were red-green or blue-yellow horizontal sinusoidal gratings, 5° × 5°, 34.3 cd/m2 mean luminance, presented at 6 Hz. Eight spatial frequencies from 0.2 to 8 cpd were used, each presented at 8 contrast levels. Contrast threshold was obtained by extrapolating second harmonic amplitude values to zero. Psychophysical contrast thresholds were measured using stimuli at 6 Hz and static presentation. Contrast sensitivity was calculated as the inverse function of the pooled cone contrast threshold. ssVECP and both psychophysical contrast sensitivity functions (CSFs) were low-pass functions for red-green gratings. For electrophysiology, the highest contrast sensitivity values were found at 0.4 cpd (1.95 ± 0.15). ssVECP CSF was similar to dynamic psychophysical CSF, while static CSF had higher values ranging from 0.4 to 6 cpd (P < 0.05, ANOVA). Blue-yellow chromatic functions showed no specific tuning shape; however, at high spatial frequencies the evoked potentials showed higher contrast sensitivity than the psychophysical methods (P < 0.05, ANOVA). Evoked potentials can be used reliably to evaluate chromatic red-green CSFs in agreement with psychophysical thresholds, mainly if the same temporal properties are applied to the stimulus. For blue-yellow CSF, correlation between electrophysiology and psychophysics was poor at high spatial frequency, possibly due to a greater effect of chromatic aberration on this kind of stimulus.

Chromatic spatial contrast sensitivity estimated by visual evoked cortical potential and psychophysics

The purpose of the present study was to measure contrast sensitivity to equiluminant gratings using steady-state visual evoked cortical potential (ssVECP) and psychophysics. Six healthy volunteers were evaluated with ssVECPs and psychophysics. The visual stimuli were red-green or blue-yellow horizontal sinusoidal gratings, 5^° × 5^°, 34.3 cd/m2 mean luminance, presented at 6 Hz. Eight spatial frequencies from 0.2 to 8 cpd were used, each presented at 8 contrast levels. Contrast threshold was obtained by extrapolating second harmonic amplitude values to zero. Psychophysical contrast thresholds were measured using stimuli at 6 Hz and static presentation. Contrast sensitivity was calculated as the inverse function of the pooled cone contrast threshold. ssVECP and both psychophysical contrast sensitivity functions (CSFs) were low-pass functions for red-green gratings. For electrophysiology, the highest contrast sensitivity values were found at 0.4 cpd (1.95 ± 0.15). ssVECP CSF was similar to dynamic psychophysical CSF, while static CSF had higher values ranging from 0.4 to 6 cpd (P < 0.05, ANOVA). Blue-yellow chromatic functions showed no specific tuning shape; however, at high spatial frequencies the evoked potentials showed higher contrast sensitivity than the psychophysical methods (P < 0.05, ANOVA). Evoked potentials can be used reliably to evaluate chromatic red-green CSFs in agreement with psychophysical thresholds, mainly if the same temporal properties are applied to the stimulus. For blue-yellow CSF, correlation between electrophysiology and psychophysics was poor at high spatial frequency, possibly due to a greater effect of chromatic aberration on this kind of stimulus.

Late Entry into HIV Care: Estimated Impact on AIDS Mortality Rates in Brazil, 2003-2006

Background: Worldwide, a high proportion of HIV-infected individuals enter into HIV care late. Here, our objective was to estimate the impact that late entry into HIV care has had on AIDS mortality rates in Brazil. Methodology/Principal Findings: We analyzed data from information systems regarding HIV-infected adults who sought treatment at public health care facilities in Brazil from 2003 to 2006. We initially estimated the prevalence of late entry into HIV care, as well as the probability of death in the first 12 months, the percentage of the risk of death attributable to late entry, and the number of avoidable deaths. We subsequently adjusted the annual AIDS mortality rate by excluding such deaths. Of the 115,369 patients evaluated, 50,358 (43.6%) had entered HIV care late, and 18,002 died in the first 12 months, representing a 16.5% probability of death in the first 12 months (95% CI: 16.3-16.7). By comparing patients who entered HIV care late with those who gained timely access, we found that the risk ratio for death was 49.5 (95% CI: 45.1-54.2). The percentage of the risk of death attributable to late entry was 95.5%, translating to 17,189 potentially avoidable deaths. Averting those deaths would have lowered the 2003-2006 AIDS mortality rate by 39.5%. Including asymptomatic patients with CD4(+) T cell counts >200 and <= 350 cells/mm(3) in the group who entered HIV care late increased this proportion by 1.8%. Conclusions/Significance: In Brazil, antiretroviral drugs reduced AIDS mortality by 43%. Timely entry would reduce that rate by a similar proportion, as well as resulting in a 45.2% increase in the effectiveness of the program for HIV care. The World Health Organization recommendation that asymptomatic patients with CD4(+) T cell counts <= 350 cells/mm(3) be treated would not have a significant impact on this scenario.