scholarly journals The Measurement of Iron Absorption

Blood ◽  
1969 ◽  
Vol 33 (3) ◽  
pp. 421-429 ◽  
Author(s):  
J. D. COOK ◽  
M. LAYRISSE ◽  
C. A. FINCH

Abstract Sources of variation in iron absorption measurements and methods of controlling them have been reviewed. There are marked differences in the mean level of absorption in different individuals and appreciable day-to-day variation in absorption in the same individual. Intersubject variations can be reduced by the selection of individuals with a more uniform iron requirement, but large variations remain which can be dealt with only by applying appropriate statistical methods to the skewed data obtained and by studying sufficient subjects to provide statistical validity to the results. Comparative studies of the availability of food iron are best carried out against a reference standard in the same subject, and intrasubject variations can be reduced by multiple dose administration.

2004 ◽  
Vol 155 (5) ◽  
pp. 142-145 ◽  
Author(s):  
Claudio Defila

The record-breaking heatwave of 2003 also had an impact on the vegetation in Switzerland. To examine its influences seven phenological late spring and summer phases were evaluated together with six phases in the autumn from a selection of stations. 30% of the 122 chosen phenological time series in late spring and summer phases set a new record (earliest arrival). The proportion of very early arrivals is very high and the mean deviation from the norm is between 10 and 20 days. The situation was less extreme in autumn, where 20% of the 103 time series chosen set a new record. The majority of the phenological arrivals were found in the class «normal» but the class«very early» is still well represented. The mean precocity lies between five and twenty days. As far as the leaf shedding of the beech is concerned, there was even a slight delay of around six days. The evaluation serves to show that the heatwave of 2003 strongly influenced the phenological events of summer and spring.


REVISTA FIMCA ◽  
2018 ◽  
Vol 5 (2) ◽  
pp. 28-31
Author(s):  
Darlan Darlan Sanches Barbosa Alves ◽  
Victor Mouzinho Spinelli ◽  
Marcos Santana Moraes ◽  
Carolina Augusto De Souza ◽  
Rodrigo da Silva Ribeiro ◽  
...  

Introdução: O estado de Rondônia se destaca como tradicional produtor de café, sendo o segundo maior produtor brasileiro de C. canephora. No melhoramento genético de C. canephora, a seleção de plantas de elevada peneira média está associada à bebida de qualidade superior. Objetivos: O objetivo desse estudo foi avaliar a variabilidade genética de clones de C. canephora para o tamanho dos grãos, mensurado a partir da avaliação da peneira média (PM). Materiais e Métodos: Para isso, foi conduzido ao longo de dois anos agrícolas experimento no campo experimental da Embrapa no município de Ouro Preto do Oeste-RO, para a avaliação da peneira média de 130 genótipos (clones) com características das variedades botânicas Conilon, Robusta e híbridos intervarietais. O delineamento experimental utilizado foi de blocos ao acaso, com quatro repetições de quatro plantas por parcela. Resultados: Não houve resultados significativos para a interação clones X anos, indicando uma maior consistência no comportamento das plantas ao longo do tempo. Porém foram observadas diferenças significativas para o tamanho dos grãos entre os genótipos avaliados, possibilitando selecionar genótipos superiores. Conclusão: Os genótipos agruparam-se em cinco classes de acordo com o teste de média, subsidiando a caracterização de um gradiente de variabilidade da característica avaliada ABSTRACTIntroduction: Coffea canephora accounts for approximately 35% of the world's coffee production. The state of Rondônia stands out as a traditional coffee producer, being the second largest Brazilian producer of C. canephora. In the classical genetic improvement of C. anephora, the selection of plants of high average sieve is associated with a drink of superior quality. Objectives: The objective of this udy was to evaluate the genetic variability of Coffea canephora clones for the agronomic medium sieve (PM). Materials and Methods: The experiment was conducted in the experimental field of Embrapa, municipality of OuroPreto do Oeste-RO, located at coordinates 10º44'53 "S and 62º12'57". One hundred thirty genotypes (clones) of botanical characteristics Conilon, Robusta and intervarietal hybrids were evaluated in the agricultural years 2013-2014 and 2014-2015. The experimental design was a randomized block design with four blocks and four plants per plot, spacing 3.5 x 1.5 meters between plants. Results: Significant difference was found for the grain size. According to the F test, at 5% probability, the genotypes were grouped into five classes according to the mean test. Conclusion: The results obtained subsidized the characterization of a variability gradient of the evaluated trait.


Neurosurgery ◽  
2003 ◽  
Vol 52 (4) ◽  
pp. 732-739 ◽  
Author(s):  
Brian L. Hoh ◽  
Bob S. Carter ◽  
Christopher M. Putman ◽  
Christopher S. Ogilvy

Abstract OBJECTIVE Intracranial residual and recurrent aneurysms can occur after surgical clipping, with risks of growth and rupture. In the past, surgical reoperation, which can be associated with higher risk than the initial operation, was the only available treatment. A combined neurovascular team that uses both surgical and endovascular therapies could maximize efficacy and outcomes while minimizing risks in these difficult cases. The indications for which surgical or endovascular treatment should be used to treat patients with residual or recurrent aneurysms, however, have not been elucidated well. We have reviewed the 10-year experience of our combined neurovascular team to determine in a retrospective manner which factors were important to treatment modality selection for patients with these residual and recurrent lesions. METHODS From 1991 to 2001, the combined neurovascular unit at the Massachusetts General Hospital treated 25 residual and recurrent previously clipped aneurysms (15 had been clipped at other centers). Only patients in whom a clip had been placed were included in the study; patients who did not have a clip placed or whose aneurysms were wrapped or coated were excluded. The radiographic studies and clinical data were reviewed retrospectively to determine the efficacy, outcomes, and factors important to the selection of treatment strategy in these patients. RESULTS The patients' clinical presentations were radiographic follow-up, 17 patients; rehemorrhage, 3; mass effect, 3; and thromboembolism, 2. The mean aneurysm recurrence or residual size was 11 mm (range, 4–26 mm). The mean interval until representation was 6.6 years (range, 1 wk–25 yr). Treatment consisted of: coiling, 11 patients; reclipping, 8; proximal parent vessel balloon occlusion, 2; extracranial-intracranial bypass with coil occlusion of aneurysm and parent vessel, 2; extracranial-intracranial bypass with clip trapping, 1; and extracranial-intracranial bypass with proximal clip occlusion of parent vessel, 1. The mean radiographic follow-up period was 11 months. Complete angiographic occlusion was found in 19 aneurysms (76%), at least 90% occlusion was found in 4 aneurysms (16%), intentional partial coil obliteration was found in 1 fusiform lesion (4%), and intentional retrograde flow was found in 1 fusiform lesion (4%). Clinical outcomes were excellent or good in 19 patients (76%). Twenty-one patients (84%) were neurologically the same after retreatment (13 remained neurologically intact, and 8 had preexisting neurological deficits that did not change). Three patients (12%) had new neurological deficits after retreatment, and one patient (4%) died. There were four complications of retreatment (16%), one of which was a fatal hemorrhage in a patient 1 month after intentional partial coil obliteration of a fusiform vertebrobasilar junction aneurysm. Factors important to the selection of treatment modality were recurrence or residual location (all posterior circulation lesions were treated endovascularly), lesion size (lesions larger than 10 mm were treated endovascularly or with the use of combined techniques), and aneurysm morphology (fusiform and wide-necked lesions were treated endovascularly or with the use of combined techniques). CONCLUSION The proper selection of surgical or endovascular treatment for residual and recurrent previously clipped aneurysms can achieve excellent radiographic efficacy with low mortality. Factors important to the selection of treatment by this combined neurovascular team were posterior circulation location, aneurysm size larger than 10 mm, and fusiform morphology, which were treated endovascularly or with the use of combined techniques because of the higher surgical risk associated with these factors. For aneurysms with lower surgical risk, such as some anterior circulation aneurysms and aneurysms smaller than 10 mm, we prefer to perform a reoperation because of superior radiographic cure without compromising the outcome.


1969 ◽  
Vol 13 (2) ◽  
pp. 117-126 ◽  
Author(s):  
Derek J. Pike

Robertson (1960) used probability transition matrices to estimate changes in gene frequency when sampling and selection are applied to a finite population. Curnow & Baker (1968) used Kojima's (1961) approximate formulae for the mean and variance of the change in gene frequency from a single cycle of selection applied to a finite population to develop an iterative procedure for studying the effects of repeated cycles of selection and regeneration. To do this they assumed a beta distribution for the unfixed gene frequencies at each generation.These two methods are discussed and a result used in Kojima's paper is proved. A number of sets of calculations are carried out using both methods and the results are compared to assess the accuracy of Curnow & Baker's method in relation to Robertson's approach.It is found that the one real fault in the Curnow-Baker method is its tendency to fix too high a proportion of the genes, particularly when the initial gene frequency is near to a fixation point. This fault is largely overcome when more individuals are selected. For selection of eight or more individuals the Curnow-Baker method is very accurate and appreciably faster than the transition matrix method.


2013 ◽  
Vol 76 (5) ◽  
pp. 763-775 ◽  
Author(s):  
José Francisco Rocha ◽  
Luis Almeida ◽  
Amílcar Falcão ◽  
P. Nuno Palma ◽  
Ana I. Loureiro ◽  
...  

PEDIATRICS ◽  
1954 ◽  
Vol 14 (5) ◽  
pp. 563-564
Author(s):  

THE WRITTEN examination of January 15, 1954, was taken by 515 candidates, a larger number than in any previous year except 1953 when there were 607 candidates Grades ranged from a lowest mark of 32.0 to a highest mark of 89.5 Inspection of the range resulted in the decision to place the passing mark at 51. On this basis there were 32, or 6.2%, who failed and were therefore ineligible for oral examination. The distribution of the grades earned by the 515 candidates is presented in the form of a histogram. As an aid to visual assessment of the nature of the distribution, a normal frequency curve computed from the mean and standard deviation of the data has been superimposed on the diagram. The distribution of the grades is clearly and impressively skewed to the left, that is, the scores tend to be massed at the high end of the scale and spread out at the low end. An examination of this type is relatively sensitive in the zone of poorer scholarship where the selection of failures is to be made and relatively insensitive in the range of higher scholarship. The intrinsic reliability of the examination has again been assessed by comparing the grade made by each candidate on his odd-numbered questions with that earned on his even-numbered questions. The comparison reveals a "probable error of estimate," P.E.m, of 2.39, a lower figure and therefore a higher degree of reliability than yielded by any previous examination. The Committee is pleased that the increase in reliability was accomplished in spite of the fact that the length of the examination was decreased from 250 grading points in 1953 to 200 grading points.


1996 ◽  
Vol 40 (1) ◽  
pp. 105-109 ◽  
Author(s):  
M Dreetz ◽  
J Hamacher ◽  
J Eller ◽  
K Borner ◽  
P Koeppe ◽  
...  

The pharmacokinetics and serum bactericidal activities (SBAs) of imipenem and meropenem were investigated in a randomized crossover study. Twelve healthy male volunteers received a constant 30-min infusion of either 1 g of imipenem plus 1 g of cilastatin or 1 g of meropenem. The concentrations of the drugs in serum and urine were determined by bioassay and high-pressure liquid chromatography. Pharmacokinetic parameters were based on an open two-compartment model and a noncompartmental technique. At the end of infusion, the mean concentrations of imipenem and meropenem measured in serum were 61.2 +/- 9.8 and 51.6 +/- 6.5 mg/liter, respectively; urinary recoveries were 48.6% +/- 8.2% and 60.0% +/- 6.5% of the dose in 12 h, respectively; and the areas under the concentration-time curve from time zero to infinity were 96.1 +/- 14.4 and 70.5 +/- 10.3 mg.h/liter, respectively (P < or = 0.02). Imipenem had a mean half-life of 66.7 +/- 10.4 min; that of meropenem was 64.4 +/- 6.9 min. The volumes of distribution at steady state of imipenem and meropenem were 15.3 +/- 3.3 and 18.6 +/- 3.0 liters/70 kg, respectively, and the mean renal clearances per 1.73 m2 were 85.6 +/- 17.6 and 144.6 +/- 26.0 ml/min, respectively. Both antibiotics were well tolerated in this single-dose administration study. The SBAs were measured by the microdilution method of Reller and Stratton (L. B. Reller and C. W. Stratton, J. Infect. Dis. 136:196-204, 1977) against 40 clinically isolated strains. Mean reciprocal bactericidal titers were measured 1 and 6 h after administration. After 1 and 6 h the median SBAs for imipenem and meropenem, were 409 and 34.9 and 97.9 and 5.8, respectively, against Staphylococcus aureus, 19.9 and 4.4 and 19.4 and 4.8, respectively, against Pseudomonas aeruginosa, 34.3 and 2.2 and 232 and 15.5, respectively, against Enterobacter cloacae, and 13.4 and 2.25 and 90.7 and 7.9, respectively, against Proteus mirabilis. Both drugs had rather short biological elimination half-lives and a predominantly renal route of elimination. Both carbapenems revealed high SBAs against clinically important pathogens at 1 h; meropenem had a higher SBA against E. cloacae and P. mirabilis, and the SBA of imipenem against S. aureus was greater than the SBA of meropenem.


2006 ◽  
Vol 69 (5) ◽  
pp. 999-1006 ◽  
Author(s):  
LUCIA RIVAS ◽  
GARY A. DYKES ◽  
NARELLE FEGAN

Shiga toxigenic Escherichia coli (STEC) serotypes are important foodborne pathogens that cause gastrointestinal disease worldwide. An understanding of how STEC strains attach to surfaces may provide insight into the potential persistence of and contamination with STEC in food environments. The initial attachment of a selection of STEC serotypes to beef muscle and adipose tissue was evaluated for isolates grown in planktonic and sessile culture. Initial experiments were performed to determine whether attachment differed among STEC strains and between the two modes of growth. Viable counts were obtained for loosely and strongly attached cells, and the strength of attachment (Sr) was calculated. All bacterial isolates grown in sessile culture attached in higher numbers to muscle and adipose tissue than did bacteria in planktonic cultures. For all attachment assays performed, mean concentrations for loosely attached cells were consistently higher than concentrations for strongly attached cells. The mean concentrations for strongly attached bacteria for planktonic and sessile cultures were significantly higher (P &lt; 0.05) on adipose than on muscle tissue. However, some strains of STEC, particularly those from sessile culture, did not differ in their attachment to muscle or adipose tissue. Sr values were not significantly different (P &gt; 0.05) among STEC isolates for all assays. No correlation was found between bacterial hydrophobicity and surface charge values (previously determined) and production of surface structures, viable counts, and Sr values. STEC grown in planktonic and sessile culture seems to behave differently with respect to attachment to muscle and adipose tissue. Cells in sessile culture may have a greater potential to strongly attach to meat surfaces.


2011 ◽  
Vol 50 (No. 2) ◽  
pp. 65-69 ◽  
Author(s):  
J. Blažek

Incidences of powdery mildew were repeatedly evaluated for two years on 1 420 young seedlings of 20 progenies (of different levels of mildew susceptibility) in a green house, and then for 10 years on 642 seedlings in an orchard. Part of the seedlings in the orchard were pre-selected for the characteristic and others not. Except for the first scoring done in the first year, there was no correlation between mildew incidence on individual seedlings in the green house and their mean performance in the orchard. The seedlings with scores above 6 (resistant or tolerant) at the first stage of evaluation in the green house, however, yielded four times more desirable seedlings after final selection in the orchard than the mean of the total. The progenies that had a better healthy state as a whole yielded more partially resistant genotypes than those with low mean scores. Therefore, the progenies that most rapidly develop infestation on the whole lot should be discarded, whereas those that retain a healthy state longer should be subjected to individual selection according to the previous item.


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