Biometric analysis of physiologically structured pure bacterial cultures recovering from starvation

1998 ◽  
Vol 44 (4) ◽  
pp. 399-404 ◽  
Author(s):  
Ralf Wilhelm ◽  
Olaf Heller ◽  
Manuela Bohland ◽  
Cordula Tomaschewski ◽  
Inge Klein ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Pseudomonas Fluorescens ◽  
Cell Volume ◽  
Distribution Patterns ◽  
Nitrosomonas Europaea ◽  
Structured Populations ◽  
Volume Distribution ◽  
Size Distributions ◽  
Biometric Analysis ◽  
Pure Bacterial Cultures

Cell volume distribution patterns were used to characterize the status of physiologically heterogeneous monospecific populations of bacteria. Such physiologically structured populations typically consist of subpopulations of cells in different metabolic and regulatory states. During recovery from starvation the differentiation of active (growing, proliferating) and quiescent (nonproliferating) subpopulations becomes detectable. Since cell volume distributions may be distorted by background noise or debris, we developed a method to extrapolate size distributions from a reduced set of reliable data. The extrapolation procedure is based upon a lognormal distribution of cell sizes. By the same approach we were able to differentiate between subpopulations even when their size ranges overlapped. The analyses of size distributions were also used, partly in combination with fluorescence microscopy, to investigate the population dynamics of Pseudomonas fluorescens and Nitrosomonas europaea during recovery from energy deprivation.Key words: physiologically heterogeneous populations, cell volume distribution, population dynamics, Pseudomonas fluorescens, Nitrosomonas europaea.

scholarly journals Asymmetric competition causes multimodal size distributions in spatially structured populations

2016 ◽  
Vol 283 (1823) ◽  
pp. 20152404 ◽  
Author(s):  
Jorge Velázquez ◽  
Robert B. Allen ◽  
David A. Coomes ◽  
Markus P. Eichhorn
Keyword(s):  
Resource Competition ◽  
Structured Populations ◽  
Necessary Condition ◽  
Small Scale ◽  
Asymmetric Competition ◽  
Size Distributions ◽  
Long Term Study ◽  
Multimodal Distributions ◽  
Using Data

Plant sizes within populations often exhibit multimodal distributions, even when all individuals are the same age and have experienced identical conditions. To establish the causes of this, we created an individual-based model simulating the growth of trees in a spatially explicit framework, which was parametrized using data from a long-term study of forest stands in New Zealand. First, we demonstrate that asymmetric resource competition is a necessary condition for the formation of multimodal size distributions within cohorts. By contrast, the legacy of small-scale clustering during recruitment is transient and quickly overwhelmed by density-dependent mortality. Complex multi-layered size distributions are generated when established individuals are restricted in the spatial domain within which they can capture resources. The number of modes reveals the effective number of direct competitors, while the separation and spread of modes are influenced by distances among established individuals. Asymmetric competition within local neighbourhoods can therefore generate a range of complex size distributions within even-aged cohorts.

Needle microepiphytes in a Douglas fir canopy: biomass and distribution patterns

1979 ◽  
Vol 57 (9) ◽  
pp. 1000-1007 ◽  
Author(s):  
George C. Carroll
Keyword(s):  
Cell Volume ◽  
Distribution Patterns ◽  
Douglas Fir ◽  
Total Cell ◽  
Microbial Cell ◽  
Microbial Cells ◽  
Cutting Out ◽  
Total Cell Volume ◽  
Volume Estimates ◽  
Cell Volumes

Distribution patterns and total cell-volume estimates for needle microepiphytes are presented for three strata in the canopy of a single old-growth Douglas fir tree. Microbial cell volume was estimated by photographing transverse sections of needles, tracing microbial profiles on Mylar film, cutting out the tracings, and determining the pooled trace weights from various zones of each needle section. Microbial cells are concentrated in the midrib groove and over the stomatal zones of individual needles. Microbial cell volume on the upper needle surfaces increases during the 1st year and declines in subsequent years. Cell volumes on the lower needle surfaces increase from the 1st to the 3rd year and decrease from the 3rd to the 4th year. An increase in microbial cell volume occurs on both upper and lower surfaces from year 7 to year 8. Total microbial cell volume in relation to available needle surface area is greatest in the lower canopy and decreases with increasing height in the canopy. The total volume of microbial cells on needles was estimated to be 1093 cm3 for the entire tree.

Evaluation of Horizontal Patternators According to International Standard Requirements for Boom Sprayers

2021 ◽  
Vol 64 (5) ◽  
pp. 1635-1646
Author(s):  
Emilio Gil ◽  
Mariana Bueno ◽  
Javier Campos ◽  
Montserrat Gallart ◽  
Joao P. A. R. Da Cunha
Keyword(s):  
Distribution Patterns ◽  
Volume Distribution ◽  
List Type ◽  
Operating Pressure ◽  
Spray Pattern ◽  
Iso Standard ◽  
Iso Standards ◽  
Technical Requirements ◽  
Spray Distribution ◽  
Technical Specifications

HighlightsHorizontal distribution according ISO Standard 16119 is a measurement procedure to evaluate boom sprayers.ISO Standards 5682-1 and 5682-2 establish technical requirements for horizontal patternators.In this study, three types of patternators were evaluated to test their capability to meet the standards.The evaluated patternators showed similar results for spray distribution patterns.Minor deviations from ISO Standard 5682 did not imply differences according ISO Standard 16119.Abstract. Uniformity of spray volume distribution is one of the officially established measurements for the evaluation of horizontal boom sprayers according to ISO Standard 16119 and requirements established by ISO Standard 16122. Measurement of spray distribution patterns requires the use of specific devices such as horizontal patternators, which are included in the technical specifications for ISO Standards 5682-1 and 5682-2. Three such devices were tested, including two manual patternators (fixed and mobile) and one electronic patternator. According to information provided by the manufacturers, all three patternators align with ISO requirements. This study evaluated and compared the results obtained with the three patternators. Specifically, the horizontal distributions measured by the patternators were evaluated and compared using four nozzle types (XR 11003, AIXR 11003, TTJ60 11003, and AITTJ60 11003), three boom heights, and three operating pressures. Tests were conducted to quantify single-nozzle spray patterns, the coefficient of variation (CV) of the entire boom distribution, the liquid recovery capability of the three patternators, and the ability to simulate the entire boom spray distribution from a single-nozzle spray pattern. Results demonstrated correct functioning of all three patternators, resulting in identical conclusions considering the requirements established in the ISO standards. The CV values of the horizontal distributions were less than 10% for all cases. Moreover, the trends in values for all the evaluated factors (nozzle type, boom height, and operating pressure) were the same, independent of the patternator used. Keywords: ISO 16119, ISO 16122, ISO 5682, Liquid recovery, Nozzle spray pattern, Patternator, Spray boom, Transverse distribution, Uniformity.

scholarly journals Estado Atual de Conhecimento de Dinâmica de Populações

2019 ◽  
Vol 23 (3) ◽  
pp. 256
Author(s):  
Anna Clara Balbina Silva ◽  
Afonso Pelli
Keyword(s):  
Population Dynamics ◽  
Full Text ◽  
Mortality Rates ◽  
Structured Populations ◽  
Exclusion Criteria ◽  
Spatially Structured Populations ◽  
The Subject ◽  
Population Interactions ◽  
Dynamic Population ◽  
Critical Challenge

Compreender os mecanismos que regulam a dinâmica das populações espacialmente estruturadas é um desafio crítico para os ecólogos e gestores de conservação. A dinâmica de populações é um ramo da ecologia que estuda as populações como sistema em atividades, relacionando as influências ambientais com a distribuição e abundância dos indivíduos e suas interações com o ambiente. O presente artigo é uma revisão bibliográfica, com o objetivo de identificar produções científicas relevantes sobre dinâmica populacional. Para isso, foram utilizados periódicos revisados por pares, na base de Periódicos Capes. A pesquisa foi realizada em junho de 2019, utilizando-se as palavras-chave para título contendo: "population dynamics" e no assunto “ecology”, a partir de 2014, quando o texto completo estava disponível. Foram considerados como critérios de exclusão os artigos publicados antes de 2014. Após a leitura dos títulos dos artigos, foram selecionados 34 artigos que foram lidos na íntegra. Em livros disponíveis no acervo da biblioteca da Universidade Federal do Triângulo Mineiro, foram selecionados quatro livros no tema dinâmica populacional. O referencial teórico aborda os aspectos da dinâmica de populações, tabela de vida, formas de crescimento e interações populacionais. Ressalta-se a necessidade de novos estudos que ainda possuem lacunas, que venha complementar e contribuir para o conhecimento de organismos que faltam ou ainda não possuem registros de estudos. Palavras-chave: Taxas de Natalidade e Mortalidade. Atributos Populacionais. Dispersão. AbstractUnderstanding the mechanisms that regulate the dynamics of spatially structured populations is a critical challenge for ecologists and conservation managers. Population dynamics is a branch of ecology that studies populations as a system in activities, relating environmental influences to the individuals’ distribution and abundance and their interactions with the environment. This article is a bibliographic review, aiming to identify relevant scientific productions about population dynamics. Thus. peer-reviewed journals were used in the Capes Periodicals base, the research was conducted in June 2019, using the keywords for title containing "population dynamics" and in the subject "ecology", from 2014, when the full text was available. Exclusion criteria were: articles published before 2014, after reading the article titles, 34 articles were selected that met the initially proposed criteria and were read in full. In books available in the library collection of the Federal University of Triângulo Mineiro, with a search for the dynamic population theme, 4 books were used. The theoretical framework addresses the aspects of population dynamics, life table, forms of growth and population interactions. It is emphasized  the need for further studies that still have gaps, which will complement and contribute to the knowledge of organisms that are missing or do not have study records. Keywords: Birth and Mortality Rates. Population Attributes. Dispersion.

scholarly journals Clinical importance of preoperative red-cell volume distribution width as a prognostic marker in patients undergoing radical surgery for pancreatic cancer

Surgery Today ◽  
2021 ◽  
Author(s):  
Chao Dang ◽  
Min Wang ◽  
Tingting Qin ◽  
Renyi Qin
Keyword(s):  
Pancreatic Cancer ◽  
Risk Factor ◽  
Nutritional Status ◽  
Cell Volume ◽  
Radical Surgery ◽  
Volume Distribution ◽  
Red Cell ◽  
Roc Curve Analysis ◽  
Distribution Width ◽  
Red Cell Volume

Abstract Background and purpose A new noninvasive biomarker is being sought to predict the prognosis of patients with pancreatic cancer. Red-cell volume distribution width (RDW), a descriptive parameter for erythrocyte variation, has been shown to have prognostic value for some tumor types. Our purpose was to assess the RDW value to predict the prognosis of patients with pancreatic cancer. Methods The subjects of this retrospective study were 792 patients who underwent radical surgery for pancreatic cancer, divided into high-RDW and low-RDW groups based on receiver operating characteristic (ROC) curve analysis (15.6%). The controlling nutritional status (CONUT) score was used to assess preoperative nutritional status. Statistical analysis was conducted to investigate the differences between the high and low RDW groups, and to explore the possibility of the RDW being used as prognostic predictor for patients with pancreatic cancer. Results The immune-nutritional status was worse in the high-RDW group than in the low-RDW group. The high-RDW group patients also had a poorer prognosis. Risk factor analysis showed that the RDW could be an independent risk factor for pancreatic cancer. Conclusions The RDW is associated with immune-nutritional status in pancreatic cancer patients and can be used as an independent prognostic factor for their postoperative survival.

scholarly journals Red Cell Volume Distribution Curves in Diagnosis of Glomerular and Non-Glomerular Haematuria

Nephron ◽  
1990 ◽  
Vol 54 (4) ◽  
pp. 366-367 ◽  
Author(s):  
David D. Gibbs ◽  
Kelvin L. Lynn
Keyword(s):  
Cell Volume ◽  
Volume Distribution ◽  
Red Cell ◽  
Red Cell Volume

scholarly journals A Stereological Analysis of NPY, POMC, Orexin, GFAP Astrocyte, and Iba1 Microglia Cell Number and Volume in Diet-Induced Obese Male Mice

Endocrinology ◽  
2015 ◽  
Vol 156 (5) ◽  
pp. 1701-1713 ◽  
Author(s):  
Moyra B. Lemus ◽  
Jacqueline A. Bayliss ◽  
Sarah H. Lockie ◽  
Vanessa V. Santos ◽  
Alex Reichenbach ◽  
...  
Keyword(s):  
Glial Fibrillary Acidic Protein ◽  
Cell Volume ◽  
Lateral Hypothalamus ◽  
Calcium Binding ◽  
Cell Number ◽  
Ionized Calcium ◽  
Volume Distribution ◽  
Stereological Analysis ◽  
Adapter Molecule ◽  
Neuronal Number

The hypothalamic arcuate nucleus (ARC) contains 2 key neural populations, neuropeptide Y (NPY) and proopiomelanocortin (POMC), and, together with orexin neurons in the lateral hypothalamus, plays an integral role in energy homeostasis. However, no studies have examined total neuronal number and volume after high-fat diet (HFD) exposure using sophisticated stereology. We used design-based stereology to estimate NPY and POMC neuronal number and volume, as well as glial fibrillary acidic protein (astrocyte marker) and ionized calcium-binding adapter molecule 1 (microglia marker) cell number in the ARC; as well as orexin neurons in the lateral hypothalamus. Stereological analysis indicated approximately 8000 NPY and approximately 9000 POMC neurons in the ARC, and approximately 7500 orexin neurons in the lateral hypothalamus. HFD exposure did not affect total neuronal number in any population. However, HFD significantly increased average NPY cell volume and affected NPY and POMC cell volume distribution. HFD reduced orexin cell volume but had a bimodal effect on volume distribution with increased cells at relatively small volumes and decreased cells with relatively large volumes. ARC glial fibrillary acidic protein cells increased after 2 months on a HFD, although no significant difference after 6 months on chow diet or HFD was observed. No differences in ARC ionized calcium-binding adapter molecule 1 cell number were observed in any group. Thus, HFD affects ARC NPY or POMC neuronal cell volume number not cell number. Our results demonstrate the importance of stereology to perform robust unbiased analysis of cell number and volume. These data should be an empirical baseline reference to which future studies are compared.

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