scholarly journals Tracheid and Pit Dimensions Hardly Vary in the Xylem of Pinus sylvestris Under Contrasting Growing Conditions

2021 ◽  
Vol 12 ◽  
Author(s):  
Magdalena Held ◽  
Andrea Ganthaler ◽  
Anna Lintunen ◽  
Walter Oberhuber ◽  
Stefan Mayr
Keyword(s):  
Growth Rate ◽  
Pinus Sylvestris ◽  
Water Transport ◽  
Functional Properties ◽  
Tree Rings ◽  
Environmental Conditions ◽  
Hydraulic Diameter ◽  
Lower Growth ◽  
Tree Survival ◽  
Lower Growth Rate

Maintaining sufficient water transport via the xylem is crucial for tree survival under variable environmental conditions. Both efficiency and safety of the water transport are based on the anatomical structure of conduits and their connections, the pits. Yet, the plasticity of the xylem anatomy, particularly that of the pit structures, remains unclear. Also, trees adjust conduit dimensions to the water transport distance (i.e., tree size), but knowledge on respective adjustments in pit dimensions is scarce. We compared tracheid traits [mean tracheid diameter d, mean hydraulic diameter dh, cell wall reinforcement (t/b)2], pit dimensions (diameters of pit aperture Da, torus Dt, margo Dm, and pit border Dp), and pit functional properties (margo flexibility F, absolute overlap Oa, torus overlap O, and valve effect Vef) of two Scots pine (Pinus sylvestris L.) stands of similar tree heights but contrasting growth rates. Furthermore, we analyzed the trends of these xylem anatomical parameters across tree rings. Tracheid traits and pit dimensions were similar on both sites, whereas Oa, O, and F were higher at the site with a lower growth rate. On the lower growth rate site, dh and pit dimensions increased across tree rings from pith to bark, and in trees from both sites, dh scaled with pit dimensions. Adjusted pit functional properties indicate slightly higher hydraulic safety in trees with a lower growth rate, although a lack of major differences in measured traits indicated overall low plasticity of the tracheid and pit architecture. Mean hydraulic diameter and pit dimension are well coordinated to increase the hydraulic efficiency toward the outer tree rings and thus with increasing tree height. Our results contribute to a better understanding of tree hydraulics under variable environmental conditions.

Caecotrophes intake in growing rabbits estimated either from urinary excretion of purine derivatives or from direct measurement using animals provided with a neck collar: effect of type and level of dietary carbohydrate

2002 ◽  
Vol 74 (1) ◽  
pp. 135-144 ◽  
Author(s):  
A. Belenguer ◽  
J. Balcells ◽  
M. Fondevila ◽  
C. Torre
Keyword(s):  
Growth Rate ◽  
Dry Matter ◽  
Dry Matter Intake ◽  
Purine Derivatives ◽  
Lower Growth ◽  
Beet Pulp ◽  
Lower Growth Rate ◽  
Maize Grain ◽  
G Ratio ◽  
Microbial N

AbstractThe present study compares estimates of caecotrophes production from urinary purine derivatives (PD) excretion with that from preventing caecotrophy by using a neck collar. A total of 64 New Zealand growing male rabbits were used to study the effect of diet composition on caecotrophes production. Diets were formulated using two sources of structural carbohydrates (fibre): alfalfa hay (AH) and sugar-beet pulp (SBP), mixed at two constant proportions, (0·75: 0·25) AH diets and (0·25: 0·75) SBP diets. Both diets included either barley or maize grain at two fibre: grain ratios (F/G, 80: 20 and 45: 55). Diets were given ad libitum. Growth rate, dry matter intake and digestibility were not modified by the grain source, although high F/G diets resulted in a lower growth rate (19·8 v. 26·4 g/day; P < 0·001). Between fibre sources, dry-matter intake and growth were higher in AH than in SBP diets (122·5 and 25·6 v. 101·6 and 20·4 g/day, respectively, P < 0·001 and P < 0·01). Rabbits given high F/G ratio and AH diets excreted more caecotrophes than those given low F/G ratio and SBP diets (19·5 and 20·9 v. 16·3 and 14·85 g/day, respectively). Microbial-N recycling through the caecotrophy process was higher when considering data from PD excretion (1·33 g/d) than when estimated by preventing caecotrophy (0·72 g/day).

Shape evolution of a spherical particle growing in supersaturated solution affected by straining flows

2016 ◽  
Vol 30 (06) ◽  
pp. 1650059
Author(s):  
Jingjing Gao ◽  
Mingwen Chen ◽  
Zidong Wang
Keyword(s):  
Growth Rate ◽  
Expansion Method ◽  
Supersaturated Solution ◽  
Shape Evolution ◽  
Interface Microstructure ◽  
Lower Growth ◽  
Ambient Flow ◽  
Multiple Variable ◽  
Lower Growth Rate ◽  
Asymptotic Expansion Method

The convection of ambient flow field has a significant influence on the pattern formation of growing particles. In this paper, we investigate the shape evolution of particles growing in supersaturated solution affected by straining flows. By using the multiple variable asymptotic expansion method, we obtain the asymptotic solution. The solution indicates that the interface microstructure is greatly affected by the straining flows. The flow results in a higher growth rate in the surface where it is incoming and a lower growth rate where it is outgoing. Besides, the flow also has effects on the concentration distribution.

Competition, Growth Rate, and CO2Fixation in Triazine-Susceptible and -Resistant Smooth Pigweed (Amaranthus hybridus)

Weed Science ◽  
1983 ◽  
Vol 31 (4) ◽  
pp. 438-444 ◽  
Author(s):  
William H. Ahrens ◽  
E. W. Stoller
Keyword(s):  
Growth Rate ◽  
Dry Weight ◽  
Dry Matter Accumulation ◽  
Lower Growth ◽  
Amaranthus Hybridus ◽  
Relative Growth ◽  
Lower Growth Rate ◽  
Net Assimilation ◽  
Synthetic Capacity ◽  
Smooth Pigweed

Triazine-susceptible (S) and -resistant (R) biotypes of smooth pigweed (Amaranthus hybridusL.) were grown in the field under competitive conditions at varying initial proportions of S and R plants. R plants were less competitive than S plants as measured by accumulation of total above-ground dry weight and seed dry weight. S and R plants were also grown in the field under non-competitive conditions at 100, 40, and 10% light. Growth rate at 10% light did not differ between S and R plants. At the two higher light intensities, dry-matter accumulation 11 weeks after seeding was about 40% less in the R plants. At 100% light, relative growth rate and net assimilation rate were lower in the R plants by about 3.5 and 19%, respectively. The light- and CO2-saturated rates of CO2fixation in intact leaves of glasshouse-grown R plants were 20% less than those in S plants. An apparent 10 and 20% greater number of chlorophyll molecules per photosystem II reaction center in R plants (as compared with S plants) grown in the field at 40 and 100% light, respectively, did not explain differences between the S and R biotypes in photo synthetic capacity. The S and R plants did not differ in specific leaf weight or chlorophyll content on a leaf-area basis. Lower growth rate of R plants may be responsible for inferior competitive ability of R biotypes and could be the result of an impaired photosynthetic capacity.

scholarly journals Physiological Characterization of an Anaerobic Ammonium-Oxidizing Bacterium Belonging to the “Candidatus Scalindua” Group

2013 ◽  
Vol 79 (13) ◽  
pp. 4145-4148 ◽  
Author(s):  
Takanori Awata ◽  
Mamoru Oshiki ◽  
Tomonori Kindaichi ◽  
Noriatsu Ozaki ◽  
Akiyoshi Ohashi ◽  
...  
Keyword(s):  
Growth Rate ◽  
Specific Growth ◽  
Maximum Specific Growth Rate ◽  
Ammonium Oxidation ◽  
Lower Growth ◽  
Content Type ◽  
Physiological Characterization ◽  
Phylogenetic Affiliation ◽  
Lower Growth Rate

ABSTRACTThe phylogenetic affiliation and physiological characteristics (e.g.,Ksand maximum specific growth rate [μmax]) of an anaerobic ammonium oxidation (anammox) bacterium, “CandidatusScalindua sp.,” enriched from the marine sediment of Hiroshima Bay, Japan, were investigated. “CandidatusScalindua sp.” exhibits higher affinity for nitrite and a lower growth rate and yield than the known anammox species.

scholarly journals Titration and Conditional Knockdown of the prfB Gene in Escherichia coli: Effects on Growth and Overproduction of the Recombinant Mammalian Selenoprotein Thioredoxin Reductase

2006 ◽  
Vol 73 (2) ◽  
pp. 432-441 ◽  
Author(s):  
Olle Rengby ◽  
Elias S. J. Arnér
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Essential Gene ◽  
Thioredoxin Reductase ◽  
Lower Growth ◽  
E Coli ◽  
Native Promoter ◽  
Lower Growth Rate ◽  
The Cost ◽  
Translational Termination

ABSTRACT Release factor 2 (RF2), encoded by the prfB gene in Escherichia coli, catalyzes translational termination at UGA and UAA codons. Termination at UGA competes with selenocysteine (Sec) incorporation at Sec-dedicated UGA codons, and RF2 thereby counteracts expression of selenoproteins. prfB is an essential gene in E. coli and can therefore not be removed in order to increase yield of recombinant selenoproteins. We therefore constructed an E. coli strain with the endogenous chromosomal promoter of prfB replaced with the titratable PBAD promoter. Knockdown of prfB expression gave a bacteriostatic effect, while two- to sevenfold overexpression of RF2 resulted in a slightly lowered growth rate in late exponential phase. In a turbidostatic fermentor system the simultaneous impact of prfB knockdown on growth and recombinant selenoprotein expression was subsequently studied, using production of mammalian thioredoxin reductase as model system. This showed that lowering the levels of RF2 correlated directly with increasing Sec incorporation specificity, while also affecting total selenoprotein yield concomitant with a lower growth rate. This study thus demonstrates that expression of prfB can be titrated through targeted exchange of the native promoter with a PBAD-promoter and that knockdown of RF2 can result in almost full efficiency of Sec incorporation at the cost of lower total selenoprotein yield.

scholarly journals Capacity Utilization in Manufacturing Industries of Pakistan

1974 ◽  
Vol 13 (3) ◽  
pp. 231-244 ◽  
Author(s):  
A.R. Kemal ◽  
Talat Alauddin
Keyword(s):  
Growth Rate ◽  
Developing Countries ◽  
Industrial Structure ◽  
Full Employment ◽  
Capacity Utilization ◽  
Theoretical Framework ◽  
Lower Growth ◽  
Production Factors ◽  
Job Opportunities ◽  
Lower Growth Rate

It is a well-known fact that capital is scarce in most of the developing countries and thus some of the production factors, such as labour, remain unemployed, leading to a lower growth rate of G.N.P. than would be possible under full employment. Additions to the stock of capital not only increase the rate of growth but also provide new job opportunities. However, in many developing countries, capital is utilised less than one-third of the time [10,p.38], The underutilization of capital obviously shrinks the growth rate of less deve¬loped countries still further. Capacity underutilization discourages technological progress which leads to an inefficient industrial structure. This presents us with a paradox: if capital is scarce in developing countries, why is it underutilized? A number of hypotheses have been advanced to explain this paradox. Some of these hypotheses relate to oligopolistic structure of the market, deficient demand, non-availability of complementary factors of production (such as skilled labour), imported inputs and government licensing policies. Moreover, when aid is available for specific projects, there is a tendency to build up addi¬tional capacity because the recipient countries prefer some aid to no-aid. However, very little has been done so far in building a theoretical framework which could be used in empirical analysis to throw light on the possible causes of capacity underutilization. Marris's theoretical framework [4] and Winston's empirical investigation of capacity utilization in Pakistan [10] are exceptions.

scholarly journals Covid-19 transmission dynamics during the unlock phase and significance of testing

2020 ◽  
Author(s):  
Abhijit Paul ◽  
Samrat Chatterjee ◽  
Nandadulal Bairagi
Keyword(s):  
Growth Rate ◽  
Large Scale ◽  
Lower Growth ◽  
Epidemic Curve ◽  
Large Scale Testing ◽  
The Social ◽  
The World ◽  
The Usa ◽  
History Of ◽  
Lower Growth Rate

The pandemic disease Covid-19 caused by SARS-COV-2, which emerged from Wuhan, China, has established itself as the most devastating disease in the history of infectious disease, affecting 216 countries/territories across the world. Different countries have developed and adopted various policies to contain this epidemic and the most common were the social distancing and lockdown. Though some countries have come out of this pandemic, the infection is still increasing and remains very serious in the rest of the world. Even when the disease is not under control, many countries have withdrawn the lockdown and going through the phase-wise unlocking process, causing a further increment in the infection rate. In such a scenario, the role of the undetected class of infected individuals has become very crucial. The present study is an attempt to understand and estimate the possible epidemic burden during the unlock phase in the presence of an undetected class. We proposed a modified SEIR model and dissected the epidemiological status of different countries with the available data. With the initial establishment of the model with the epidemic data of four countries, which have already attained the epidemic peak, the study focused more on countries like India and the USA, where the epidemic curve is still growing, but the unlock process has started. As a straightforward result, we noticed a significant increase in the undetected and detected infected cases under the ongoing unlock phase. Under such conditions, our recalibration exercise showed that an increase in the testing could revert the existing growth rate of the infected cases to the lower growth rate of the lockdown period. Our present study emphasizes on the implementation of 3T principles, trace, test, and treat, to contain the epidemic. The significance of large scale testing in controlling the epidemic is true for both India and the USA though they have different socio-economic conditions. The use of repurposing drugs may further decrease the infected cases and help the disease controlling process. We believe our proposed strategy obtained through a mathematical model will help to make a better policy for the unlock phase.

Plane Poiseuille Flow of Two Compatible Polymers: Influence of the Interphase on the Flow Stability

2005 ◽  
Vol 128 (1) ◽  
pp. 27-33 ◽  
Author(s):  
François Rousset ◽  
Patrick Bourgin ◽  
Liviu-Iulian Palade
Keyword(s):  
Growth Rate ◽  
Poiseuille Flow ◽  
Lower Growth ◽  
Polymeric Systems ◽  
Stable Domain ◽  
System A ◽  
Interdiffusion Process ◽  
Diffusion Phenomena ◽  
Lower Growth Rate ◽  
Energy Dissipated

This paper deals with coextrusion flows of two compatible polymers which are known to be generally more stable than the same flows of incompatible systems. We show that the weak response to disturbance of such flows can be predicted by considering an interphase of nonzero thickness (corresponding to an interdiffusion zone) instead of a purely geometrical interface between the two layers. As a first step we try to explain the weak sensibility to disturbance of compatible systems by the sole presence of this intermediate layer. For that purpose we study the linear stability response to very long waves of a three-layer phase Poiseuille flow with an inner thin layer which represents the interphase. Although this fact is an approximation, it nevertheless takes into account the diffusion phenomena which are generated in the interphase. This first approach (corresponding to a reduction in the effective viscosity ratio) is shown to explain the diminished growth rates but not the reduction in the size of the unstable region. As a second step, we formulate an energetic approach of the problem. We evaluate the energy dissipated during the interdiffusion process and the variation of kinetic energy of the global system. A modified growth rate is then determined by taking into account the energy dissipated by the interdiffusion process. This lower growth rate enables us to explain the increase of the stable domain in the case of compatible polymeric systems.

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