Validity and reproducibility of two semi-quantitative alcohol frequency questionnaires for the Colombian population

OBJECTIVE: To determine the relative validity and reproducibility of two alcohol intake frequency questionnaires (AFQ-A; AFQ-B), designed to classify subjects according to their alcohol intake level, in Bucaramanga, Colombia. METHOD: One hundred and nine randomly selected subjects, aged between 20 and 60 years, completed three 30-day semi-quantitative alcohol intake records (30-DR). The AFQs were applied three months after the last 30-DR. AFQ-A contained 53 items; AFQ-B contained five items, with the alcoholic drinks for AFQ-B selected by Max_r. The correlation and agreement between alcohol intake assessed with the AFQs and the 30-DR were obtained using Pearson's correlation coefficient (r), Lin's concordance correlation coefficient (rhoC), Spearman's rank correlation coefficient (rS), Bland and Altman's limits of agreement (LOA) and Cohen's weighted kappa statistic (Kw). RESULTS: The reproducibility of the 30-DR was poor; rS ranged from 0.33 to 0.41. The reproducibility of the AFQs was higher, with rS between 0.50 and 0.73. The agreement (Kw) of the 30-DR and the AFQs was 0.40. The lower and upper LOA were between -56.4% and -11.0%. The AFQs and 30-DR were well correlated. Assessment of relative validity between the two methods yielded r values for alcohol between 0.52 and 0.60, which reduced to 0.20-0.29 after energy adjustment. CONCLUSIONS: These AFQs may be useful to rank subjects according to their alcohol intake. The AFQ-B is easy and quick to apply, and is also highly cost-effective.     

Belowground carbon allocation patterns in a dry Mediterranean ecosystem: A comparison of two models

Total belowground C allocation (TBCA) accounts for a large fraction of gross primary production, it may overtake aboveground net primary production, and contributes to the primary source of detrital C in the mineral soil. Here, we measure soil respiration, water erosion, litterfall and estimate annual changes in C stored in mineral soil, litter and roots, in three representative land uses in a Mediterranean ecosystem (late-successional forest, abandoned agricultural field, rain-fed olive grove), and use two C balance approaches (steady-state and non-steady-state) to estimate TBCA. Both TBCA approaches are compared to assess how different C fluxes (outputs and inputs) affect our estimates of TBCA within each land use. In addition, annual net primary productivity is determined and C allocation patterns are examined for each land use. We hypothesized that changes in C stored in mineral soil, litter and roots will be slight compared to soil respiration, but will still have a significant effect on the estimates of TBCA. Annual net primary productivity was 648 ± 31.5, 541 ± 42.3 and 324 ± 22.3 g C m⁻² yr⁻¹ for forest, abandoned agricultural field and olive grove, respectively. Across land uses, more than 60% of the C was allocated belowground. Soil respiration (F_S) was the largest component in the TBCA approaches across all land uses. Annual C losses through water erosion were negligible compared to F_S (less than 1%) and had little effect on the estimates of TBCA. Annual changes in C stored in the soil, litter layer and roots were low compared to F_S (16, 24 and 10% for forest, abandoned agricultural field and olive grove, respectively), but had a significant effect on the estimates of TBCA. In our sites, an assumption that Δ[C_S + C_R + C_L]/Δt = 0 will underestimate TBCA, particularly in the abandoned agricultural field, where soil C storage may be increasing more rapidly. Therefore, the steady-state model is unsuited to these Mediterranean ecosystems and the full model is recommended.     

Using occupancy and population models to assess habitat conservation opportunities for an isolated carnivore population

An isolated population of the fisher (Martes pennanti) in the southern Sierra Nevada, California, is threatened by small size and habitat alteration from wildfires, fuels management, and other factors. We assessed the population’s status and conservation options for its habitat using a spatially explicit population model coupled with a fisher probability of occurrence model. The fisher occurrence model was selected from a family of generalized additive models (GAM) generated using numerous environmental variables and fisher detection–nondetection data collected at 228 survey arrays sampled repeatedly during 2002–2006. The selected GAM accounted for 69% of the Akaike weight using total above-ground biomass of trees, latitude-adjusted elevation, and annual precipitation averaged over a 5 km² moving window. We estimated equilibrium population sizes (or carrying capacities) within currently occupied areas, and identified likely population source, sink, and expansion areas, by simulating population processes for 20 years using different demographic rates, dispersal distances, and territory sizes. The population model assumed that demographic parameters of fishers scale in proportion to habitat quality as indexed by the calculated probability of fisher occurrence. Based on the most defensible range of parameter values, we estimate fisher carrying capacity at ∼125–250 adults in currently occupied areas. Population expansion into potential habitat in and north of Yosemite National Park has potential to increase population size, but this potential for expansion is predicted to be highly sensitive to mortality rates, which may be elevated in the northern portion of the occupied range by human influences, including roadkill and diseases carried by domestic cats and dogs.     

Tree fallows: A comparison between five tropical tree species

The natural abundance of ¹⁵N and ¹³C, conventional soil analyses, and biomass production by maize were used to study the influence of five tropical tree species on soils and their fertility. The experiment was conducted in Morogoro, Tanzania, to compare Cassia (Senna) siamea, Eucalyptus camaldulensis, E. tereticornis (all non-N₂-fixing), Leucaena leucocephala, Prosopis chilensis (both N₂-fixing), and a grass fallow. Maize biomass production, which was correlated with N uptake (P=0.001), was higher on soils from plots with 5-year-old Leucaena and Prosopis spp. compared to the grass fallow, while other tree species had less favourable effects on maize growth. The per cent N was higher in soil and ¹⁵N of soil total N was lower under Prosopis sp. compared to soil under other tree species, which suggests an input from N₂ fixation by Prosopis sp. A transfer of fixed N to maize or to understorey grass species was, however, not indicated by the ¹⁵N natural abundance. Prosopis sp. contributed more C to the soil than the other four tree species; the difference in ¹³C between soils from Prosopis sp. plots and from grass fallow plots showed that the tree contributed 11% to the total C of the soil over a period of 8 years. The leaves of the N₂-fixing species had a low ratio of lignin+phenols to N, and maize growth was negatively correlated with this parameter. The Eucalyptus spp. had leaves with a high lignin+phenols to N ratio, contributed very little C to the soil, and lowered the soil pH.     

Protective effect of yoghurt consumption on Helicobacter pylori seropositivity in a Mexican population

OBJECTIVE: The aim of the study was to determine the relationship between fermented and unfermented dairy product consumption and Helicobacter pylori seropositivity in a Mexican population. DESIGN: Dietary interviews were conducted as part of a population-based case-control study in 2005. Serum was obtained for each participant to determine H. pylori seropositivity status. Adjusted odds ratios were estimated from multivariate logistic regression models. SETTING: Mexico City, Mexico. SUBJECTS: A random sample of 464 healthy adult residents. RESULTS: The overall seroprevalence of H. pylori in the study sample was 75.4%. In fully adjusted models, compared with those who did not consume yoghurt, there was a protective effect of eating up to one serving per week of yoghurt and more than one serving per week of yoghurt (odds ratio (OR) = 0.57, 95% confidence interval (CI) 0.35-0.94 and OR = 0.45, 95% CI 0.24-0.86, respectively), with a P for trend of 0.01. There were no effects for the consumption of unfermented dairy products (milk and cheese). CONCLUSIONS: This study suggests that yoghurt consumption may have a protective effect against H. pylori seropositivity. Additional studies are needed to determine whether consumption of yoghurt or other fermented dairy products can prevent or eradicate H. pylori infection.     

连续五年生物垃圾堆肥施用后地中海蔬菜种植系统中土壤有机碳的变化

Biowaste compost can influence soil organic matter accumulation directly or indirectly. A 5-year experiment was conducted to assess the influence of biowaste compost on the process of soil aggregation and soil organic carbon(SOC) accumulation in a Mediterranean vegetable cropping system. The study involved four treatments: biowaste compost(COM), mineral NPK fertilizers(MIN), biowaste compost with half-dose N fertilizer(COMN), and unfertilized control(CK). The SOC stocks were increased in COM, COMN, and MIN by 20.2, 14.9, and 2.4 Mg ha~(-1)over CK, respectively. The SOC concentration was significantly related to mean weight diameter of aggregates(MWD)(P 0.05, R~2= 0.798 4) when CK was excluded from regression analysis. Compared to CK, COM and COMN increased the SOC amount in macroaggregates( 250 μm) by 2.7 and 0.6 g kg~(-1)soil, respectively, while MIN showed a loss of 0.4g kg~(-1)soil. The SOC amount in free microaggregates(53–250 μm) increased by 0.9, 1.6, and 1.0 g kg~(-1)soil for COM, COMN, and MIN, respectively, while those in the free silt plus clay aggregates( 53 μm) did not vary significantly. However, when separating SOC in particle-size fractions, we found that more stable organic carbon associated with mineral fraction 53 μm(MOM-C) increased significantly by 3.4, 2.2, and 0.7 g kg~(-1)soil for COM, COMN, and MIN, respectively, over CK, while SOC amount in fine particulate organic matter(POM) fraction(53–250 μm) increased only by 0.3 g kg~(-1)soil for both COM and COMN, with no difference in coarse POM 250 μm. Therefore, we consider that biowaste compost could be effective in improving soil structure and long-term C sequestration as more stable MOM-C.     

A comparison of lime requirements by five methods on grassland mineral soils in Ireland

Liming is necessary for good nutrient availability and crop growth. Lime use in Ireland is now the lowest in half a century. A recent study shows that grassland mineral soils in Ireland has a mean pH of 5.4 and mean lime requirement (LR) of 9.3 t/ha ground limestone. There have been a number of studies in the USA to re-evaluate LR, but little activity in the European Union (EU) in recent years. The primary aim of our research was to compare five methods for estimating LR, which included the Shoemaker–McLean–Pratt (SMP) buffer method currently used in Ireland (IRL), the Sikora buffer method used at the University of Kentucky (UKY), Ca(OH)₂ titration used at University of Georgia (UGA), the modified Mehlich buffer method used at Penn State University (PSU) and the UK RothLime model, using 57 representative grassland mineral soils from Ireland with a pH range from 4.8 to 6.6. The secondary aim was to explore an alternative to the SMP buffer that does not involve the use of toxic chemicals. The results show good agreement between the pH measured by the Irish and three US laboratories and reasonably good agreement in LR estimated by five methods. The main conclusions are: (1) a significant proportion of grassland on mineral soils in Ireland would benefit from liming to increase soil pH, (2) on average, LRs as recommended in Ireland are higher than those advised elsewhere , ( 3) the target pH in Ireland is high compared with that in other countries and should be reduced from pH 6.5 to 6.2, (4) the SMP buffer method should be replaced by a suitable alternative and, in principle, any of the four methods studied would be suitable, (5) to find the most suitable alternative for accurate LR advice it would be necessary to compare the different methods to the actual LR from incubation of representative soils with calcium hydroxide.     

Cancer risk to Japanese population from the consumption of inorganic arsenic in cooked hijiki

The cancer risk posed by inorganic arsenic (iAs) ingestion via the consumption of hijiki seaweed, a common Japanese food item known to accumulate pentavalent arsenic, was estimated. Fourteen households were asked to supply three portions of cooked hijiki (boiled and fried with vegetables and fried bean curd, etc.), as usually cooked and served per person in each household. The monthly consumption frequency of cooked hijiki was assessed by questionnaire: it was typically two to three times a month in most households. The mean daily consumption of cooked hijiki was estimated to be 6.5 g/day (range = 1.1-14 g/day, median = 5.5 g/day) by multiplying one serving quantity (grams) by the monthly frequency of consumption. The concentration of iAs [As(III) + As(V)] in the cooked hijiki was determined after homogenization, freeze-drying, 0.07 mol/L HCl extraction, and high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICPMS). The concentration of iAs ranged from 0.4 to 2.8 mg/kg (wet weight basis) in the cooked hijiki, and iAs intake from cooked hijiki was calculated to be 0.0005-0.023 mg/day. On the basis of these data and the oral slope factor [1.5E0 (mg/kg/day) (-1)] reported by the U.S. EPA for iAs, the mean skin cancer risk through cooked hijiki consumption was calculated to be 2.4 x 10(-4) (range = 1.6 x 10(-6) -7.0 x 10(-4)), which exceeded the acceptable level of 10(-5). Taking the risk of other cancers (bladder, lung, etc.) into consideration, the contribution to cancer occurrence through the consumption of hijiki seaweed may not be negligible.     

A comparison of five instruments for measuring soil strength in cultivated and uncultivated cereal seedbeds

A torsional shear box, shear vane. cone penetrometer, drop-cone penetrometer and pocket penetrometer were used to measure soil strength at several depths less than 150 mm in cultivated and uncultivated seedbeds in a loam and a sandy clay loam. From the shear box results, cohesion was higher and the angle of friction was lower in the sandy clay loam than in the loam. Angle of friction was independent of cultivation but cohesion was higher in uncultivated than in cultivated soil. Despite these differences cone resistance was similar in both soils above 70 mm depth. Vane shear strength and drop-cone penetration, although empirical, indicated strength differences between soils and cultivations similar to those found with the torsional shear box. Vane shear strength, at 42 kPa, was about twice as high as cohesion in the sandy clay loam and, at 33 kPa, over four times as high as cohesion in the loam. These overestimates increased with increasing bulk density. The range of measurement of the pocket penetrometer was inadequate to cover the range of soil strengths encountered. The coefficient of variation within plots for cone resistance decreased from 76 per cent at 10 mm depth to about 22 per cent at 70 mm depth and below, and for vane shear strength it was 33 per cent near the soil surface. The drop-cone penetrometer results were the most variable, reflecting the log-normal distribution of penetrations. The cone penetrometer was the fastest method, followed by the shear vane, drop-cone penetrometer and torsional shear box in that order.     

Use of a population model to assess the impact of longline fishing on wandering albatross Diomedea exulans populations

An age-structured model of a wandering albatross Diomedea exulans population is developed to stimulate population trends over time, using demographic parameters from the population at Possession Island, Crozets, during 1968–1986. The simulation results portray a population decreasing at a rate of 2·29% per year, which concurs with global population trends. Sensitivity analyses of model parameters indicate that both adult and juvenile mortality are contributing to the decrease. Wandering albatross mortality is presumed to have increased as a result of deaths caused by longline fishing vessels; such deaths are likely to be relatively more frequent among young, naive birds. The model is used to investigate the potential impacts of new longline fisheries such as that for Patagonian toothfish Dissostichus eleginoides in Antarctica. Assuming longline fishing operations affect juveniles more than adults, there is a time lag of 5–10 years before further decreases in population numbers are reflected in the breeding population. Also, because wandering albatrosses are long-lived, population growth rates take approximately 30–50 years to stabilize after a perturbation. Consequently, caution must be exercised when interpreting population trends; short-term (<20 year) estimates may not provide good indications of long-term trends.     

中国食物消费随人口结构变化分析

中国目前正在经历快速的人口年龄结构调整,其必会对中国食物消费产生巨大的影响。该文利用中国健康与营养调查(China health and nutrition survey,CHNS)数据,对中国不同年龄居民的消费特征进行了分析,在此基础上,根据生命周期理论与Leslie人口模型,预测2030年前中国各年龄的人口规模,进而判断人口年龄结构变化对中国主要食物消费量的影响。研究结果显示:1)不同年龄段居民的不同类别的食物消费规律明显,大致可分为4种类型:倒"U"型曲线消费(口粮、水产品、白酒)、"U"型曲线消费(牛奶)、阶段性直线消费(肉类3阶段消费规律、禽类2阶段消费规律)、无差异消费(禽蛋)。2)人口年龄结构对中国食物消费总量产生了明显的影响,包括正向影响(口粮、水产品、白酒)、负向影响(肉类、禽类)、先负后正影响(牛奶)、无明显影响(禽蛋)。3)在影响程度上,中国人口年龄结构的演变对肉类、禽类消费量的负向影响最为明显,至2030年,分别达到4.9%与11.2%的程度,对白酒的正向影响也达到8.2%的程度。对口粮、水产品、牛奶的影响程度相对较小,而对禽蛋几乎没有影响。由此可见,人口年龄结构的变化会使中国居民肉类消费需求增长及由此带来的粮食需求压力趋缓。     

An inter-laboratory comparison of multi-enzyme and multiple substrate-induced respiration assays to assess method consistency in soil monitoring

The use of indicators in soil monitoring schemes to detect changes in soil quality is receiving increased attention, particularly the application of soil biological methods. However, to date, the ability to compare information from different laboratories applying soil microbiological techniques in broad-scale monitoring has rarely been taken into account. This study aimed to assess the consistency and repeatability of two techniques that are being evaluated for use as microbiological indicators of soil quality: multi-enzyme activity assay and multiple substrate-induced respiration (MSIR). Data were tested for intrinsic (within-assay plate) variation, inter-laboratory repeatability (geometric mean regression and correlation coefficient) and land-use discrimination (principal components analysis). Intrinsic variation was large for both assays suggesting that high replicate numbers are required. Inter-laboratory repeatability showed diverging patterns for the enzyme assay and MSIR. Discrimination of soils was significant for both techniques with relatively consistent patterns; however, combined laboratory discrimination analyses for each technique showed inconsistent correspondence between the laboratories. These issues could be addressed through the adoption of reliable analytical standards for biological methods along with adequate replication. However, until the former is addressed, dispersed analyses are not currently advisable for monitoring schemes.     

A comparison of competitiveness and persistence amongst five strains of Rhizobium tripolii

Five strains of Rhizohium trifolii were used to inoculate Trifolium subterraneum cv. Woogenellup sown into two soils with naturally-occurring populations of R. trifolii. In the 1st year all inoculant strains used singly were present at high frequency in the sampled nodule populations from the inoculated plots. Where an inoculant containing a mixture of equal parts of the 5 strains was used. one strain (WU95) predominated at both sites.The persistence of the strains was followed for a further 3 years at one site. Three of the strains WU95, CC2480a and WU290, were maintained at a high frequency (>75% of nodules sampled) for the entire period, but the other two strains showed poor persistence in this environment. Highly effective strains of rhizobia, not identifiable as inoculant strains, nor present in the nodule population at the first sampling, appeared during the course of the study. One strain. WU290, showed a high degree of variation in symbiotic effectiveness between single colony isolates from the stock culture and also between field isolates that were serologically identical with this strain.     

Vitamin D status in a rural population of northern Norway with high fish liver consumption

OBJECTIVE: To assess vitamin D status and the impact of three fish meals consisting of cod liver and fresh cod-liver oil on the plasma level of vitamin D metabolites in an area with high consumption of cod liver and cod-liver oil. DESIGN: Experimental field study. METHODS: Thirty-two volunteers from the Skjerv?y (70 degrees N) municipality in northern Norway were recruited to consume three traditional m?lje meals, consisting of cod, cod liver, fresh cod-liver oil and hard roe, in one week. The liver and fresh cod-liver oil consumed by the participants were weighed and recorded. Blood samples were collected before the first meal, and subsequently 12 h and 4 days after the last meal. The blood samples were analysed for the vitamin D metabolites 25-hydroxyvitamin D (25(OH)D) and 1,25-dihydroxyvitamin D (1,25(OH)2D). All participants answered a semi-quantitative food-frequency questionnaire, which was used to estimate usual daily nutrient intake. The study was carried out in the last part of March 2001. RESULTS: The median daily vitamin D intake estimated from the questionnaire was 9.9 microg. The proportion of subjects with baseline 25(OH)D level below 50 nmol l(-1) was 15.4% and none were below 37.5 nmol l(-1). Only "m?lje consumption" and "time spent in daylight" were significantly associated with baseline log 25(OH)D. The mean total intake of vitamin D in the three servings was 272 microg (standard deviation 94 microg), ranging from 142 to 434 microg. Relative to baseline plasma concentration, the mean level of 25(OH)D decreased slightly in both post-consumption samples (P< or =0.03), while 1,25(OH)2D peaked 12 h after the final meal (P=0.03). CONCLUSION: Three m?lje meals provided, on average, an amount of vitamin D equal to 54 times the recommended daily dose. Subjects with food consumption habits that included frequent m?lje meals during the winter sustained satisfactory vitamin D levels in their blood, in spite of the long "vitamin D winter" (i.e. absence of ultraviolet-induced vitamin D production in the skin).     

A comparison of methods for soil microbial population and biomass studies

A comparison was made of 15 different techniques which are used in assessing soil microbial populations and/or biomasses. These include direct observations (fungal standing crop, fluorescein diacetate active mycelia, acridine orange stained bacteria), cultural methods (bacterial plate counts), physiological methods (total microbial, bacterial and fungal biomasses, O₂-uptake), soil enzyme analyses (dehydrogenase, catalase, alkaline and acid phosphatase, protease, amylase), and ATP-analyses. The various techniques were applied to six soils known to have different microbial characteristics. The results are discussed with respect to the convertability of counts and measurements into microbial biomasses, the variability of the techniques, the correlations within comparable groups of methods, and the practical limitations in application of individual methods to different soils.     

Pollution of carbonate soils in a Mediterranean climate due to a tailings spill

The retention walls in a pond containing the residues from the pyrite mine of Aznalcóllar (southern Spain) broke open on 25 April 1998, spilling approximately 6 × 10⁶ m³ of polluted water and toxic tailings, which affected some 55 km². Drying and aeration of the tailings resulted in oxidation, forming an acidic solution with high pollutant contents, the effects of which were studied in a calcareous soil. The infiltration of this solution markedly affected only the first 12 mm of the soil, where strong acidification caused the weathering of the carbonates, and where the fine mineral particles were hydrolysed. The SO₄²⁻ ions in the acidic solution precipitated almost entirely at this depth, forming gypsum, hydroxysulphates and complex sulphates. The Fe³⁺ ions also precipitated there, mainly in amorphous or poorly crystallized forms, adsorbing to As, Sb, Tl and Pb dissolved in the acidic solution. The Al³⁺ ions, though partly precipitating in the acidic layer, accumulated mostly where the soil pH exceeded 5.5 (12–14 mm in depth). They did so primarily as amorphous or poorly crystallized forms, adsorbing to Cu dissolved in the acidic solution. The Zn²⁺ and Cd²⁺ ions accumulated mainly at pH > 7.0 (19–21 mm in depth), being adsorbed chiefly by clay mineral. After 15 months, only the first 20 mm of the soil were acidified by the oxidation of the tailings and most of the pollutants did not penetrate deeper than 100 mm. Consequently, the speed of the cleanup of the toxic spill is not as important as a thorough removal of tailings together with the upper 10 cm of the soil.