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PubMed2002

Role of dietary calcium and available phosphorus in the aetiology of tibial dyschondroplasia in growing turkeys.

1. Large White male turkeys from a heavy commercial male-line were fed 16 diets containing 4 concentrations of calcium (6, 10, 14 and 18 g/kg) and available phosphorus (3, 5, 7 and 9 g/kg) in a 4 x 4 factorial experiment. There were three replicates (pens) of each treatment and the skeletal health, morphology and mineral status of 4 turkeys from each pen were assessed at 7, 10 and 13 weeks of age. 2. The prevalence of tibial dyschondroplasia increased after 7 weeks of age and was present in 50 and 71% of turkeys respectively at 10 and 13 weeks. The lesion was localised in the caudal aspect of the proximal tibiae. Dietary calcium and available phosphorus did not affect the prevalence of the lesion except in turkeys on the diet containing 6 g calcium/kg, where body weight and the incidence of tibial dyschondroplasia were low. 3. Histological investigation showed no evidence of rachitic changes. 4. Low dietary calcium was associated with lower tibial plateau angles at 10 and 13 weeks of age. Tibial torsion and the angle of rotation were not affected by dietary treatments or age. Tibial torsion and the angle of rotation were not affected by dietary treatments or age. 5. Increasing dietary calcium increased tibial radiodensity, cortical density and the widths of the cortex and proximal tibiotarsus. Radiodensities increased to 10 weeks and were significantly lower at 13 weeks of age. 6. Bone ash, calcium and phosphorus declined with age, particularly between 10 and 13 weeks, whereas bone calcium: phosphorus ratios were not affected by dietary treatment or age. 7. Dietary calcium was positively associated with blood calcium and calcium ion concentrations and was without effect on blood phosphorus. Available phosphorus was associated positively with increased blood phosphorus and lower calcium ion concentrations but had no effect on total calcium. Alkaline phosphatase activity was low at high concentrations of dietary calcium with low available phosphorus and there was higher activity on diets containing low calcium and high available phosphorus.

Age Factors↗

PubMed2000

Set-size and frequency-of-occurrence judgements in young and older adults: the role of the availability heuristic.

Two experiments examined the cognitive processes underlying judgements of set size and judgements of frequency of occurrence in young (Experiments 1 and 2) and older (Experiment 2) adults. Previous research has implicated the availability heuristic in set-size judgements, whereas an automatic processing mechanism has been implicated in judgements of frequency of occurrence. In the current experiments, path analysis was employed to investigate the role of an availability bias in performance on the judgement tasks. In Experiments 1 and 2, both types of judgement were influenced by repetition frequency of words independent of the availability (recall) of specific exemplars. Experiment 2 extended the investigation to include age differences. Although older adults' recall performance was poorer overall, the availability bias was age invariant, and there were no age differences in either set-size or frequency-of-occurrence judgements. Our results indicate that both set-size and frequency-of-occurrence judgements are independent of the availability bias evident in recall, and they support the notion that an automatic processing mechanism underlies both types of judgement.

Adult↗

PubMed1977

Determination of zinc availability in foods by the extrinsic label technique.

The absorption of intrinsic 65Zn and extrinsic 65Zn from corn and liver was measured in rats. No significant difference between the absorption of intrinsic- and extrinsic-label was observed. These results indicate that endogenous zinc and exogenous 65Zn enter a common pool prior to being absorbed from the intestine. Since extrinsic 65Zn enters a common pool with intrinsic zinc, whole-body absorption of extrinsic 65Zn can be used to obtain an accurate estimate of the availability of zinc in food. The availability of zinc in human breast milk, in cow's milk, in infant formulas, and in reconstituted dry milk was analyzed by use of the extrinsic label. The zinc in human breast milk was most available (59%) while the zinc in the infant formulas was the least available (26 to 37%). Zinc from both raw and cooked corn was more available than zinc from either cooked or uncooked rat liver.

Absorption↗

PubMed1981

A comparison of in vivo and in vitro methods for determining availability of iron from meals.

A comparison is made between in vitro and human and rat in vivo methods for estimating food iron availability. Complex meals formulated to replicate meals used by Cook and Monsen (Am J Clin Nutr 1976;29:859) in human iron availability trials were used in the comparison. The meals were prepared by substituting pork, fish, cheese, egg, liver, or chicken for beef in two basic test meals and were evaluated for iron availability using in vitro and rat in vivo methods. When the criterion for comparison was the ability to show statistically significant differences between iron availability in the various meals, there was substantial agreement between the in vitro and human in vivo methods. There was less agreement between the human in vivo and the rat in vivo and between the in vivo and the rat in vivo and between the in vitro and the rat in vivo methods. Correlation analysis indicated significant agreement between in vitro and human in vivo methods. Correlation between the rat in vivo and human in vivo methods were also significant but correlations between the in vitro and rat in vivo methods were less significant and, in some cases, not significant. The comparison supports the contention that the in vitro method allows a rapid, inexpensive, and accurate estimation of nonheme iron availability in complex meals.

Animals↗

PubMed1991

Reassessment of trans fatty acid availability in the US diet.

This report updates our 1984 estimate of the amount of trans fatty acids available for consumption in the US diet, namely 7.6 g.person-1.d-1, for 1989. Compared with 1984 data, we found essentially no change in 1989 for the per capita availability of trans fatty acids from total food service fats and oils. The 1989 value we obtained for industrial fats and oils is somewhat higher than the value we reported for 1984, in part because more complete data were available for 1989. In contrast, however, since 1984 the per capita availability of trans fatty acids from household salad and cooking oils, household shortenings, and all margarines and spreads (retail, food service, and industrial) has decreased. Overall, our reassessed (1989) value for total trans fatty acid availability is 8.1 g.person-1.d-1, which is similar to our original estimate. This total may increase slightly (approximately 0.3 g.person-1.d-1) as a result of the recent switch by many establishments from the use of tallow to partially hydrogenated vegetable oils for frying.

Dairy Products↗

PubMed2003

European food availability databank based on household budget surveys: the Data Food Networking initiative.

BACKGROUND: There is a need in Europe for sources of dietary data that would provide a regular flow of comparable nutrition information. In this context, the Data Food Networking (DAFNE) project has been developing a cost-effective food databank that allows monitoring of food availability within and between countries. METHODS: The DAFNE project has developed a common classification system for the food and socio-demographic variables recorded in the national household budget surveys. Daily individual food availability was estimated for each participating country and basic descriptive statistics were used to depict the nutritional habits of the populations. RESULTS: The DAFNE databank is freely accessible through DafneSoft (www.nut.uoa.gr). Three figures, based on Greek, Norwegian and UK data respectively, were selected to indicatively present the potential of the DAFNE data in order to monitor changes in the availability of 12 food groups over time; to study the effect of education in the total added lipid availability; and to follow time changes in fresh vegetable availability between manual and non-manual households. CONCLUSION: The HBS data allows the highlighting of issues related to nutrition surveillance. The application of the DAFNE methodology in developing a databank of standardized dietary data offers a realistic option for monitoring dietary habits in Europe. Benefiting from this potential, the European Union may additionally consider the undertaking of a pan-European individual dietary survey, in a sub-sample of the household budget population.

Budgets↗

PubMed2003

Age differences in home computer availability and use.

OBJECTIVES: The purpose of this study was to determine whether age differences in home computer availability and use are due to variations in compositional characteristics (e.g., income or disabilities) of age cohorts. METHODS: Data are drawn from the September 2001 Current Population Survey and its supplement on computer and Internet use (N = 71,182). Patterns of age differences in home computer use are examined using Multiple Classification Analysis with controls for several measures of compositional variability (employment status, marital status, Hispanic origin and race, gender, family income, living arrangements, education, and number of disabilities). RESULTS: Even though home computer availability declines steadily with age, a portion of this zero-order relationship is due to composition effects, with their greatest impact occurring at the oldest ages. Among persons living in households where a computer is available, use also declines with age, but these age differences in computer use are less due to compositional differences. DISCUSSION: The lower rates of home computer availability and use exhibited by older persons may be accounted for to some extent by compositional characteristics negatively associated with availability and, to a lesser extent, use of computers, although unmeasured attitudes, experience, and support undoubtedly play a role.

Adult↗

PubMed1996

SES and ethnic differences in perceived caregiver availability among young-old Mexican Americans and non-Hispanic whites.

Differences in perceived caregiver availability were examined among a random sample of Mexican American (MA) and non-Hispanic white (NHW) young-old residents (58-74 years old) in three socioeconomically distinct neighborhoods in San Antonio, Texas. For MAs across all three socioeconomic status (SES) groups, being female, widowed, and having more chronic illnesses were associated with a lesser likelihood of perceived caregiver availability. SES and number of children were not associated with perceived caregiver availability. Among MAs and NHWs of middle- and upper-SES, being male, married, and of upper-SES were associated with a greater likelihood of perceived caregiver availability. The number of children modified the associations of both SES and ethnic group with perceived caregiver availability.

Aged↗

PubMed2005

Neighbourhood deprivation and alcohol consumption: does the availability of alcohol play a role?

BACKGROUND: Previous studies suggest that the physical availability of alcohol may mediate the association between neighbourhood-level material deprivation and alcohol consumption. This study tests the relationships between neighbourhood-level deprivation, alcohol availability, and individual-level alcohol consumption using a multilevel analysis. METHODS: Data are from cross-sectional surveys conducted between 1979 and 1990 as part of the Stanford Heart Disease Prevention Program (SHDPP). Women and men (n = 8197) living in four northern/central California cities and 82 neighbourhoods were linked to neighbourhood deprivation variables derived from the US census (e.g. unemployment, crowded housing) and to measures of alcohol availability (density of outlets in the respondent's neighbourhood, nearest distance to an outlet from the respondent's home, and number of outlets within a half mile radius of the respondent's home). Separate analyses were conducted for on- and off-sale outlets. RESULTS: The most deprived neighbourhoods had substantially higher levels of alcohol outlet density than the least deprived neighbourhoods (45.5% vs 14.8%, respectively). However, multilevel analyses showed that the least deprived neighbourhoods were associated with the heaviest alcohol consumption, even after adjusting for individual-level sociodemographic characteristics (OR 1.30, CI 1.08-1.56). Alcohol availability was not associated with heavy drinking and thus did not mediate the relationship between neighbourhood deprivation and heavy alcohol consumption. CONCLUSIONS: Although alcohol availability is concentrated in the most deprived neighbourhoods, women and men in least deprived neighbourhoods are most likely to be heavy drinkers. This mismatch between supply and demand may cause people in the most deprived neighbourhoods to disproportionately suffer the negative health consequences of living near alcohol outlets.

Adult↗

PubMed1997

Biological evaluations of commercial dicalcium phosphates as sources of available phosphorus for broiler chicks.

One thousand male Hubbard chicks were used in a 21-d study (10 birds per battery cage) to determine relative biological availability of phosphorus in seven samples of commercial dicalcium phosphate, expected to contain variable amounts of monocalcium phosphate. Five samples were from established producers in Brazil and two from the U.S. Pure calcium phosphate dibasic dihydrate was used as the reference standard. Phosphates were added to the corn-soybean basal diet (22.5% CP; 0.4% total phosphorus) to provide 0.1, 0.2, and 0.3% supplemental phosphorus. The calcium level was 1.0% for all diets. Left tibias were removed for bone ash (BA) and bone strength (BS) determination. Body weight, feed intake (FI), BA, BS, and plasma phosphorus increased (P < 0.01) and plasma calcium and alkaline phosphatase decreased (P < 0.01) with increasing dietary phosphorus regardless of source. The availability of phosphorus for each test phosphate was determined by slope ratio, with BW, BA, and BS regressed on phosphorus added within each phosphorus source. A relative biological value (RBV) was calculated based on BW, BA, and gain:feed ratio. Availability based on BW ranged from 97.07 to 110.41%. When BA was the criterion, values were 80.32 to 107.84% and for BS were 79.34 to 110.52%. The RBV ranged from 97.55 to 100.60%. Phosphate sources did not vary greatly in phosphorus availability. Overall phosphorus availability averages were higher for BW (103%) and RBV (99%) and lowest for BA (96%) and BS (94%).

Alkaline Phosphatase↗

PubMed2000

Influence of light availability on leaf structure and growth of two Eucalyptus globulus ssp. globulus provenances.

Light availability strongly affects leaf structure of the distinctive ontogenetic leaf forms of Eucalyptus globulus Labill. ssp. globulus. Late-maturing plants from St. Marys, Tasmania and early maturing plants from Wilsons Promontory, Victoria (hereafter referred to as Wilsons Prom.) were grown for 9 months in 100, 50 or 10% sunlight. Growth, biomass and leaf area were significantly reduced when plants were grown in 10% sunlight. Provenance differences were minimal despite retention of the juvenile leaf form by the Tasmanian plants throughout the study. The time taken for initiation of vegetative phase change by the Wilsons Prom. saplings increased with decreasing light availability, but the nodal position of change on the main stem remained the same. Both juvenile and adult leaves remained horizontal in low light conditions, but became vertical with high irradiance. Leaf dimensions changed with ontogenetic development, but were unaffected by light availability. Juvenile leaves retained a dorsiventral anatomy and adult Wilsons Prom. leaves retained an isobilateral structure despite a tenfold difference in light availability. Stomatal density and distribution showed ontogenetic and treatment differences. At all irradiances, juvenile leaves produced the smallest stomata and adult leaves the largest stomata. Amphistomy decreased with decreasing irradiance. Detrended, correspondence analysis ordination highlighted the structural changes influenced by ontogenetic development and light availability. Adult leaves had characteristics similar to the xeromorphic, sun-leaf type found in arid, high-light conditions. Although juvenile leaves had characteristics typical of mesomorphic leaves, several structural features suggest that these leaves are more sun-adapted than adult leaves.

Eucalyptus↗

PubMed2006

Nitrogen availability, local light regime and leaf rank effects on the amount and sources of N allocated within the foliage of young walnut (Juglans nigra x regia) trees.

Early season leaf growth depends largely on nitrogen (N) provided by remobilization from storage, and many studies have tested the effect of N availability to roots on the amount of N provided for new leaf development by remobilization. Although it is well known that the light regime experienced by a leaf influences the amount of N per unit leaf area (LA), the effect of the local light regime on the amount of N derived either directly from root uptake or from remobilization for early season leaf growth has never been tested at an intra- canopy scale. The objective of this study was to quantify the relative importance of (1) N availability to roots, (2) local light regime experienced by the foliage (at the shoot scale) and (3) leaf rank along the shoot, on the total amount of N allocated to leaves and on the proportions of N provided by remobilization and root uptake. To quantify the importance of N uptake and remobilization as sources of leaf N, potted hybrid walnut trees (Juglans nigra L. x regia L.) were grown outdoors in sand and fed with a labeled ((15)N) nutrient solution. By removing the apical bud, the trees were manipulated to produce only two shoots. The experimental design had two factors: (1) high (HN; 8 mol N m(-3)) and low (LN; 2 mol N m(-3)) N availability; and (2) high (HL; 90% of incident photosynthetically active photon flux (PPF)) and low (LL; 10% of incident PPF) light. Total leaf N per tree was unaffected by either N availability or irradiance. The HN treatment increased the amount of leaf N derived from root uptake at the whole-tree scale (typically around 8 and 2% in the HN and LN treatments, respectively). Nitrogen allocation within foliage of individual trees was controlled by the local light regime, which strongly affected individual leaf characteristics as leaf mass per unit LA and area- based amount of leaf (N(a)). Decreasing the light availability to a branch decreased the amount of N allocated to it, benefiting the less shaded branches. In contrast, shading of the lower branch did not affect the fraction of total leaf N remobilized for either the lower, shaded branch or the upper, unshaded branch. The relevance of these findings for tree growth modeling is discussed.

Biological Transport↗

PubMed1999

Acute isoniazid exposures and antidote availability.

BACKGROUND: Over the past 10 years the reported incidence of acute isoniazid (INH)-related poisonings has increased, with 507 cases reported in 1996. Parenteral pyridoxine is the antidote for INH-induced seizures, but 5-g aliquot recommended to treat an ingestion of unknown quantity of INH is not always readily available to emergency physicians. OBJECTIVE: To determine the hospital availability of pyridoxine. METHODS: One hundred thirty questionnaires were distributed nationwide to the pharmacies and emergency departments (ED) of hospitals containing pediatric emergency medicine (PEM) fellowships and/or emergency medicine (EM) residencies. Questions were posed regarding the availability, quantity, location, and deemed importance of pyridoxine at each institution. RESULTS: Responses were received from 81% of the hospitals with fellowships and 80% of the hospitals with residencies. Half of the former and one third of the latter reported not having the recommended 5-g aliquot available. Eighty percent of the hospitals with PEM programs and 71% with EM residencies with an adequate stock store it in the hospital's pharmacy, as opposed to in the ED. Thirty-four states were represented, 18 of which have experienced an increase in tuberculosis (TB) from 1993 to 1994; 6/18 (33%) of those did not have the pyridoxine available, and 7/18 (39%) did not deem it necessary. CONCLUSIONS: Our results imply that between one third and one half of the respondents would be ill-equipped to treat acute INH neurotoxicity. Establishing regional distribution centers may alleviate this deficiency, specifically in urban areas with a high incidence or a positive percent increase in TB.

Acute Disease↗

PubMed2006

Field comparison of commercially available short-term radon detectors.

We performed a comparison of commercially available short-term radon detectors in order to determine the accuracy and precision of the detectors under actual field conditions. We exposed fifteen radon detectors, under field conditions, from each of six companies to a reference radon concentration. Five of the six companies tested did not pass the U.S. Environmental Protection Agency's previously established accuracy guideline (all individual relative errors </= 25%) and four of the six companies failed the EPA's precision guideline [coefficient of variation </= 10% at 150 Bq m (4 pCi L)]. The findings suggest that the performances of commercially available radon detectors exposed under actual field conditions may not be as accurate or precise as those detectors available prior to the close of the EPA's National Radon Proficiency Program in 1998. It is unknown if this one-time "snap shot" represents the overall reliability of the accuracy and precision of commercially available radon detectors. Nonetheless, the findings suggest that additional double-blind testing of commercially available radon detectors under actual field conditions is warranted.

Air Pollutants, Radioactive↗

PubMed2005

Incidence of sexually transmitted diseases and HIV infection related to perceived HIV/AIDS threat since highly active antiretroviral therapy availability in men who have sex with men.

OBJECTIVE: Concerns have been expressed regarding increase in risky sex because of the availability of antiretroviral treatments in Western countries. GOAL: The goal of this longitudinal study was to investigate the association between highly active antiretroviral therapy (HAART)- and postexposure prophylaxis-related beliefs and the incidence of sexually transmitted diseases (STDs) and new HIV infections in men who have sex with men (MSM). STUDY: Data on the incidence of STDs and new HIV infection, and the level of agreement with different HAART- and PEP-related beliefs from 151 HIV-negative MSM were compiled. RESULTS: Of all MSM, 65.6% tested negative for any STDs and 7 men HIV seroconverted. Perceiving less HIV/AIDS threat since HAART availability and younger age were significantly associated with a higher incidence of STDs. Perceiving less need for safe sex since HAART availability was significantly associated with an increased likelihood of HIV seroconversion. CONCLUSIONS: The results support the assumption that there is an association between the incidence of STDs and a decreased perception of HIV/AIDS threat resulting from HAART availability. Less perceived need for safe sex since HAART availability was associated with HIV seroconversion.

Adult↗

PubMed2004

Influence of food availability on demography and local population dynamics in a long-lived seabird.

Few studies have addressed the effects of food availability as a proximate factor affecting local adult survival in long-lived organisms and their consequences at local population dynamics. We used capture-recapture analysis of resightings of 10 birth cohorts of ringed Audouin's gulls, Larus audouinii, to estimate adult survival and dispersal (both emigration and immigration). For the first time, permanent emigration (the transient effect in capture-recapture analysis) was modelled for the whole population and not only for the newly marked birds. Gulls exploit to a large extent fishes discarded from trawlers, and a trawling moratorium established since 1991 has decreased food supply for the colony. This was used as a natural experiment of food availability to assess its effects on adult survival and emigration. These and other demographic parameters were used in a projection modelling to assess the probabilities of extinction of the colony under two scenarios of lower and higher food availability. Food availability (together with the age of individuals) influenced emigration probabilities, but not adult survival, which was estimated at 0.91 (s.e. = 0.02). When food was in shorter supply during the chick-rearing period, emigration was very high (ca. 65%) for younger breeders, although this rate decreased sharply with age. Probabilities of extinction were very high when food availability was low, and when environmental stochasticity was introduced, and only stochastic immigration from the outside seemed to prevent extinction. The results highlight the importance of dispersal processes in the population dynamics of long-lived organisms.

Animal Nutritional Physiological Phenomena↗

PubMed2001

Effect of winter cover crops on soil nitrogen availability, corn yield, and nitrate leaching.

Biculture of nonlegumes and legumes could serve as cover crops for increasing main crop yield, while reducing NO3 leaching. This study, conducted from 1994 to 1999, determined the effect of monocultured cereal rye (Secale cereale L.), annual ryegrass (Lolium multiflorum), and hairy vetch (Vicia villosa), and bicultured rye/vetch and ryegrass/vetch on N availability in soil, corn (Zea mays L.) yield, and NO3-N leaching in a silt loam soil. The field had been in corn and cover crop rotation since 1987. In addition to the cover crop treatments, there were four N fertilizer rates (0, 67, 134, and 201 kg N ha(-1), referred to as N0, N1, N2, and N3, respectively) applied to corn. The experiment was a randomized split-block design with three replications for each treatment. Lysimeters were installed in 1987 at 0.75 m below the soil surface for leachate collection for the N 0, N 2, and N 3 treatments. The result showed that vetch monoculture had the most influence on soil N availability and corn yield, followed by the bicultures. Rye or ryegrass monoculture had either no effect or an adverse effect on corn yield and soil N availability. Leachate NO3-N concentration was highest where vetch cover crop was planted regardless of N rates, which suggests that N mineralization of vetch N continued well into the fall and winter. Leachate NO3-N concentration increased with increasing N fertilizer rates and exceeded the U.S. Environmental Protection Agency's drinking water standard of 10 mg N l(-1) even at recommended N rate for corn in this region (coastal Pacific Northwest). In comparisons of the average NO3-N concentration during the period of high N leaching, monocultured rye and ryegrass or bicultured rye/vetch and ryegrass/vetch very effectively decreased N leaching in 1998 with dry fall weather. The amount of N available for leaching (determined based on the presidedress nitrate test, the amount of N fertilizer applied, and N uptake) correlated well with average NO3-N during the high N leaching period for vetch cover crop treatment and for the control without the cover crops. The correlation, however, failed for other cover crops largely because of variable effectiveness of the cover crops in reducing NO3 leaching during the 5 years of this study. Further research is needed to determine if relay cover crops planted into standing summer crops is a more appropriate approach than fall seeding in this region to gain sufficient growth of the cover crop by fall. Testing with other main crops that have earlier harvest dates than corn is also needed to further validate the effectiveness of the bicultures to increase soil N availability while protecting the water quality.

Agriculture↗

PubMed2001

Phosphate availability regulates root system architecture in Arabidopsis.

Plant root systems are highly plastic in their development and can adapt their architecture in response to the prevailing environmental conditions. One important parameter is the availability of phosphate, which is highly immobile in soil such that the arrangement of roots within the soil will profoundly affect the ability of the plant to acquire this essential nutrient. Consistent with this, the availability of phosphate was found to have a marked effect on the root system architecture of Arabidopsis. Low phosphate availability favored lateral root growth over primary root growth, through increased lateral root density and length, and reduced primary root growth mediated by reduced cell elongation. The ability of the root system to respond to phosphate availability was found to be independent of sucrose supply and auxin signaling. In contrast, shoot phosphate status was found to influence the root system architecture response to phosphate availability.

Arabidopsis↗