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At least 1,783 records · Page 99Linked to original sources
PubMed2005

Can children and adolescents use photographs of food to estimate portion sizes?

OBJECTIVE: The goals of this study were to investigate whether children and adolescents can accurately estimate portion sizes of preweighed food by viewing photographs of food, and whether age influences the ability to estimate food portion sizes. SUBJECTS: A total of 63 male and female volunteers aged 9-19 y participated in the study. DESIGN: Each participant received a photographic booklet with photograph series of 13 food items. Participants over 10 y of age were asked to estimate portion sizes of food on 34 plates placed in front of them by comparing the different portions to corresponding photographs of food. Younger participants were asked to estimate portion sizes of food on 17 plates by comparing the portions to photographs. RESULTS: Participants made 2019 comparisons between actual food portion sizes and photographs of food portion sizes. On average, 60% of the comparisons were made correctly. A photograph directly adjacent to the photograph depicting the correct portion size was chosen in 35% of the comparisons and 5% of the comparisons were made incorrectly. Portion sizes were estimated more accurately when the actual served portions of food had exactly the same appearance as the foods portrayed in the photographic booklet. No differences existed between children's and adolescents' abilities to estimate portion sizes using photographs. CONCLUSIONS: Large variability may exist in an individual's capability of choosing a photograph that correctly depicts food portion sizes, but the error at the group level is quite small. These data indicate that a photographic booklet of foods can be a useful tool for portion size estimates in these age groups. SPONSORSHIP: The Norwegian Foundation for Health and Rehabilitation through Norwegian Health Association.

Adolescent↗
PubMed2005

An evaluation of a colour food photography atlas as a tool for quantifying food portion size in epidemiological dietary surveys.

OBJECTIVE: To test the validity of a colour food photography atlas for quantifying portion size eaten compared with weighed foods. DESIGN: The colour food photography atlas was prepared by cooking, weighing and taking digital photographs of three portion sizes of 434 foods and beverages typical of the Italian diet. SUBJECTS AND INTERVENTIONS: In all, 448 male and female volunteers aged 6-60 y from a wide variety of social backgrounds completed 9075 assessments of food portions eaten at lunch and dinner in relation to a set of colour food photographs during 8 weeks of investigation. The amounts of foods eaten by individuals in five different cafeterias in Pavia, Northern Italy, were weighed by trained investigators at the time of serving and, within 5-10 min of the end of the meal, each subject was asked to quantify all foods consumed with reference to one of the three food photographs or in terms of virtual portions among those shown in the photographs. RESULTS: Multiple regression analysis shows that weights of portion sizes chosen from the set of photographs are significantly associated (P<0.05) to weights of eaten portions (beta=0.81; R(2)=0.70) and are independent of age, gender and BMI. The differences between mean weights of the portions chosen by individuals from photographs and mean weights of eaten foods are significant for all food categories (P<0.05), except for bread. However, because of the very large number of observations, the mean differences are very small (range: from +23.2 g (+11.2%) for first courses to -1.3 g (-2.7%) for bread). Bland-Altman plots show that first courses limits of agreement are wide because the dispersion is increasing while weights are rising. CONCLUSIONS: The use of a series of three photographs and virtual portion sizes being associated with relatively small errors, our findings support the validity of using this colour food photography atlas as a tool for quantifying food portion size in epidemiological dietary surveys on different age groups of Italian subjects.

Adolescent↗
PubMed2003

The estimation of food portion sizes: a comparison between using descriptions of portion sizes and a photographic food atlas by children and adults.

BACKGROUND: Food Photographs and standard portion sizes have been used with adults to assess portion size when recording dietary intake. The effectiveness of these methods may be reduced when memory/recall is required and children may have problems using these techniques. METHODS: Adults (47) and children (37) were recruited from amongst university personnel, their children and children's friends to assess portion sizes of nine self-served amounts of selected food items using food photographs and standard descriptions of portion sizes. Portion sizes were estimated directly after self-serving and three - 4 days later. RESULTS: Substantial differences in the estimate of portion sizes were observed for most foods regardless of the method used or the age of the subjects, median difference range: -52-100%. For children there were greater errors using both methods than for adults. Significant differences were found between the two methods of estimating weight. The food atlas provided higher median estimated weights for the majority of the food items. There were very few differences in the estimation of portion sizes between the two testing periods. CONCLUSION: The findings would suggest that either an alternative method or a modification of the methods used here for estimating portion sizes in young subjects, for example standard food portion sizes for children of different ages such as those that are being developed by the Food Standards Agency, would be more appropriate.

Adolescent↗
PubMed2002

Direction of cross-modal information transfer affects human brain activation: a PET study.

The purpose of this study was to determine the functional organization of the human brain involved in cross-modal discrimination between tactile and visual information. Regional cerebral blood flow was measured by positron emission tomography in nine right-handed volunteers during four discrimination tasks; tactile-tactile (TT), tactile-visual (TV), visual-tactile (VT), and visual-visual (VV). The subjects were asked either to look at digital cylinders of different diameters or to grasp the digital cylinders with the thumb and index finger of the right hand using haptic interfaces. Compared with the motor control task in which the subjects looked at and grasped cylinders of the same diameter, the right lateral prefrontal cortex and the right inferior parietal lobule were activated in all the four discrimination tasks. In addition, the dorsal premotor cortex, the ventral premotor cortex, and the inferior temporal cortex of the right hemisphere were activated during VT but not during TV. Our results suggest that the human brain mechanisms underlying cross-modal discrimination have two different pathways depending on the temporal order in which stimuli are presented.

Adult↗
PubMed2002

Balancing visual weights.

An experiment is described which is based on a peculiar response index, the visual balance, which involves the match of visual weight. The stimulus consists of a pair of grey fields, differing in their spectral reflectance factor, and the experiment is designed to determine how the balance condition depends on their relative sizes. This dependence is found to be linear when the test object is considered globally; non-linear when considering its fine intra-pair geometrical characteristics.

Adult↗
PubMed2006

Approach to the diagnosis of neuroendocrine lung neoplasms: variabilities and pitfalls.

With the publication of the spectrum of neuroendocrine proliferations and neoplasms and the features and criteria for diagnosing neuroendocrine lung neoplasms, there is more agreement in making a specific pathologic diagnosis of a neuroendocrine lung neoplasm. However, problems exist, especially in diagnosing well-differentiated neuroendocrine carcinomas (atypical carcinoids), large-cell neuroendocrine carcinomas, and even some small-cell lung cancers. Some of this disagreement has to do with a pathologist's perception of sizes and shapes of cells. Nonneuroendocrine small-cell carcinomas exist and include small-cell squamous cell carcinoma, small cell adenocarcinoma, and basaloid carcinoma. Nonneuroendocrine lung cancers, especially large-cell undifferentiated carcinoma and poorly differentiated adenocarcinoma, not infrequently express neuroendocrine markers immunohistochemically.

Adenocarcinoma↗
PubMed1979

[A contribution to the psychophysiology of infantile dysmegalopsy (author's transl)].

A 9 year old boy was able to evoke microptic experiences voluntarily. Clinical and historical signs of minimal brain dysfunction were present. An epileptic etiology could neither be proven nor ruled out. Synchronized EEG- and Video recording allowed us to analyze the EEG and the corresponding behavior by using sequential spectral analysis of the EEG data. Coinciding with a progressive increase in rhythmic 6-7 cps. activity we observed a behavior which appeared to correspond to a state of narrowed attention. He signalized the onset of a micropsy a few seconds after the transition from this pattern into one which showed a relative voltage decrease and the reappearance of some alpha-activity. The end was signalized by him coinciding with the recurrence of normal waking activity. Our findings--like those of others--suggest that the gradual development of hypnagogic phenomena is bound to a state of lowered vigilance. The reappearance of alpha activity and the voltage decrease seem to represent an unstable intermediary state with partial arousal preceding the restitution of normal wakefulness. Since the onset of the micropsy was signalized only after manifestation of the intermediary EEG-state, we conclude that partial arousal is a prerequisite for giving an indication of hypnagogic experiences in a quasi retrospective manner.

Arousal↗
PubMed1982

[Determination of the real size of an object on the fundus of the living eye].

A method is described which allows the real diameter of an object on the fundus to be determined by means of a system of curves which are the result of trigonometrical calculations and which give an approximate value; only a photograph of the fundus, a measurement of the ametropia and of the radius of the anterior surface of the cornea are required. The results can be corrected with a second graph, which makes use of the length of the optical axis of the eye.

Cornea↗
PubMed1981

[Determination of visual acuity by the visually evoked cortical potential (author's transl)].

Monocularly evoked cortical potentials were recorded monopolarly (3 cm above Prot. occ. ext. sup.) to steady-state checkerboard stimuli (check sizes 1.4 to 26 min, rev. freq. 7/s, mean luminance 10.8 cd/m2, field diameter 4.5 deg., centr. fix.). For a number of visual acuities (obtained by inserting plus lenses up to 3.0 dpt) the smallest check size evoking reliable VECPs was related to the visual acuities obtained at a visual test chart. The use of 20 instead of 100 per cent contrast stimuli provided a significant decrease of slope of threshold check size versus visual acuity, resulting in a three-fold increase in the resolution of data. The method permits the evaluation of visual acuities between 0.1 and 1.0 in normals and patients within limits of +/- log 0.1 (1 sigma) and +/- log 0.2 visual acuity (2 sigma).

Adult↗
PubMed1981

[Visually evoked cortical potentials (VECP) in patients with doubtful impairment of central vision (author's transl)].

Visual evoked cortical potential (VECP) to non-structured, brightness (luminance) stimuli do not provide an appropriate means for assessing the degree of impaired central vision. In comparison, visually evoked cortical potentials to structured (patterned) stimuli presented by pattern reversal of equal mean luminance are highly susceptible to visual changes caused by reduced central vision. Employing different check sizes, the use of checkerboard pattern reversal VECPs permits, independently of the patient, to assess the impairment of central vision.

Accommodation, Ocular↗
PubMed1976

Did Ptolemy understand the moon illusion?

Ptolemy is often wrongly credited with an explanation of the moon illusion based on the size-distance invariance principle. This paper elucidates the two Ptolemaic accounts: one in the Almagest, based on atmospheric refraction, and the other in the Optics, based on the difficulty of looking upwards. It is the latter passage which has been thought to refer to size-distance invariance, but it is more probable that it refers to the idea that the visual rays are diminished by the force of gravity (i.e. that the retinal image is reduced in size). Alhazen was probably the first author to explain the illusion by the size-distance invariance principle, and Roger Bacon the first to explain the enlarged apparent distance of the horizon by the presence of intervening objects. Della Porta was the first to credit Ptolemy with these explanations, and this mistake was repeated by many subsequent authors.

Astronomy↗
PubMed1977

Effects of gap size between shaft and fins and of angle of fins on the Müller--Lyer illusion.

Assimilation theory was employed to generate quantitative predictions relating the ingoing Müller--Lyer illusion to both angle of fin and gap between shaft and fin. Gap sizes were varied from zero to 18 mm in steps of 2 mm, and angles of fins were varied from 30 degrees to 180 degrees in steps of 30 degrees. Five subjects adjusted the length of a comparison line to match the apparent length of the shaft at each combination of gap size and angle of fin. It was predicted that the gap necessary for a reversed illusion to occur, and the gap at which the maximal reversed effect occurred, would be inversely related to angle of fins. Empirical functions verified the predictions.

Humans↗
PubMed1978

Size and position invariance in the visual system.

The encoding of simple features such as lines and angles leads naturally to size and position invariance when these features are analyzed symbolically in terms of structure and connectedness. No such analysis is possible for a spatial frequency encoding, however, as all a priori indications of pattern unity are lost. An additional transformation of spatial frequency information is therefore demonstrated that automatically derives a size invariant representation of form. The feasibility of the transform scheme in the visual system is outlined with a hypothetical processing sequence. It is found that the organization of cells in the striate cortex shows a marked similarity to an intermediate stage of the proposed sequence.

Fourier Analysis↗