Showing papers by "Lund University published in 1996"
TL;DR: This biennial Review summarizes much of particle physics, using data from previous editions.
12,798 citations
TL;DR: The cell content of 12 bacterial phospholipid fatty acids (PLFA) was determined in bacteria extracted from soil by homogenization/centrifugation and the soil content of the PLFA 18:2ω6 was correlated with the ergosterol content, which supports the use of this PLFA as an indicator of fungal biomass.
Abstract: The cell content of 12 bacterial phospholipid fatty acids (PLFA) was determined in bacteria extracted from soil by homogenization/centrifugation. The bacteria were enumerated using acridine orange direct counts. An average of 1.40×10-17 mol bacterial PLFA cell-1 was found in bacteria extracted from 15 soils covering a wide range of pH and organic matter contents. With this factor, the bacterial biomass based on PLFA analyses of whole soil samples was calculated as 1.0–4.8 mg bacterial C g-1 soil C. The corresponding range based on microscopical counts was 0.3–3.0 mg bacterial C g-1 soil C. The recovery of bacteria from the soils using homogenization/centrifugation was 2.6–16% (mean 8.7%) measured by PLFA analysis, and 12–61% (mean 26%) measured as microscopical counts. The soil content of the PLFA 18:2ω6 was correlated with the ergosterol content (r=0.92), which supports the use of this PLFA as an indicator of fungal biomass. The ratio 18:2ω6 to bacterial PLFA is therefore suggested as an index of the fungal:bacterial biomass ratio in soil. An advantage with the method based on PLFA analyses is that the same technique and even the same sample is used to determine both fungi and bacteria. The fungal:bacterial biomass ratio calculated in this way was positively correlated with the organic matter content of the soils (r=0.94).
2,256 citations
SUNY Downstate Medical Center1, McMaster University2, McGill University3, Harvard University4, Toronto General Hospital5, University of Birmingham6, University of Pisa7, Dalhousie University8, University of Manchester9, University College London10, University of California, Los Angeles11, United Hospitals12, Lund University13, Johns Hopkins University14, St. Vincent's Health System15
TL;DR: This damage index for SLE records damage occurring in patients with SLE regardless of its cause and was demonstrated to have content, face, criterion, and discriminant validity.
Abstract: Objective. To develop and perform an initial validation of a damage index for systemic lupus erythematosus (SLE).
Methods. A list of items considered to reflect damage in SLE was generated through a nominal group process. A consensus as to which items to be included in an index was reached, together with rules for ascertainment. Each center submitted 2 assessments, 5 years apart, on 2 patients with active and 2 with inactive disease, of whom 1 had increased damage and the other had stable disease. Analysis of variance was used to test the factors physician, time, amount of damage, and activity status.
Results. Nineteen physicians completed the damage index on 42 case scenarios. The analysis revealed that the damage index could identify changes in damage seen in patients with both active and inactive disease. Patients who had active disease at both time points had a higher increase in damage. There was good agreement among the physicians on the assessment of damage in these patients.
Conclusion. This damage index for SLE records damage occurring in patients with SLE regardless of its cause. The index was demonstrated to have content, face, criterion, and discriminant validity.
2,095 citations
TL;DR: New growth curves are presented based on data from four Scandinavian centres for 759 ultrasonically estimated foetal weights in 86 uncomplicated pregnancies, revealing better the true distribution of SGA foetuses and neonates and are suggested for use in perinatological practice.
Abstract: Available standard intrauterine growth curves based on birthweights underestimate foetal growth in preterm period. New growth curves are presented based on data from four Scandinavian centres for 759 ultrasonically estimated foetal weights in 86 uncomplicated pregnancies. Mean weight of boys exceeded that of girls by 2-3%. A uniform SD value of 12% of the mean weight was adopted for the standard curves as the true SD varied non-systematically between 9.1 and 12.4%. Applied to an unselected population of 8663 singleton births, before 210 days of gestation, 32% of birthweights were classified as small-for-gestational age (SGA; i.e. below mean - 2 SD); the corresponding figures were 11.1% for gestational ages between 210 and 258 days, and 2.6% for ages of 259 days or longer. The new growth curves reveal better the true distribution of SGA foetuses and neonates, and are suggested for use in perinatological practice.
1,647 citations
Eugenia E. Calle1, Clark W. Heath1, H. L. Miracle-McMahill1, R. J. Coates2 +185 more•Institutions (41)
TL;DR: Breast cancer and hormonal contraceptives: Collaborative reanalysis of individual data on 53297 women with breast cancer and 100239 women without breast cancer from 54 epidemiological studies as mentioned in this paper.
1,253 citations
TL;DR: The Integrated Biosphere Simulator (IBIS) as mentioned in this paper is a terrestrial biosphere model that integrates a wide range of biophysical, physiological, and ecological processes in a single, physically consistent modeling framework.
Abstract: Here we present a new terrestrial biosphere model (the Integrated Biosphere Simulator - IBIS) which demonstrates how land surface biophysics, terrestrial carbon fluxes, and global vegetation dynamics can be represented in a single, physically consistent modeling framework. In order to integrate a wide range of biophysical, physiological, and ecological processes, the model is designed around a hierarchical, modular structure and uses a common state description throughout. First, a coupled simulation of the surface water, energy, and carbon fluxes is performed on hourly timesteps and is integrated over the year to estimate the annual water and carbon balance. Next, the annual carbon balance is used to predict changes in the leaf area index and biomass for each of nine plant functional types, which compete for light and water using different ecological strategies. The resulting patterns of annual evapotranspiration, runoff, and net primary productivity are in good agreement with observations. In addition, the model simulates patterns of vegetation dynamics that qualitatively agree with features of the natural process of secondary succession. Comparison of the model's inferred near-equilibrium vegetation categories with a potential natural vegetation map shows a fair degree of agreement. This integrated modeling framework provides a means of simulating both rapid biophysical processes and long-term ecosystem dynamics that can be directly incorporated within atmospheric models.
1,233 citations
TL;DR: An alternative interpretation of why hydrophilic surfaces and macromolecules remain well separated in water is suggested, in which hydration forces are either attractive or oscillatory, and where repulsions have a totally different origin.
Abstract: The conventional explanation of why hydrophilic surfaces and macromolecules remain well separated in water is that they experience a monotonically repulsive hydration force owing to structuring of water molecules at the surfaces. A consideration of recent experimental and theoretical results suggests an alternative interpretation in which hydration forces are either attractive or oscillatory, and where repulsions have a totally different origin. Further experiments are needed to distinguish between these possibilities.
1,225 citations
TL;DR: In this article, an instrument for measuring organizational structure and climate for creativity and innovation is described, and the authors make recommendations for using the instrument to develop interventions to promote organizational innovation.
Abstract: This article describes an instrument for measuring organizational structure and climate for creativity and innovation. Its application and validation in organizational settings is also described. Recommendations are made for using the instrument to develop interventions to promote organizational innovation.
1,072 citations
TL;DR: In this article, different fermentation organisms among bacteria, yeast, and recombinant were reviewed with emphasis on their performance in lignocellulosic hydrolysates, i.e., can withstand potential inhibitors.
1,062 citations
TL;DR: In this article, a coupled carbon and water flux model is used to calculate, for each PFT, the leaf area index (LAI) that maximizes net primary production (NPP), subject to the constraint that NPP must be sufficient to maintain this LAI.
Abstract: The equilibrium terrestrial biosphere model BIOME3 simulates vegetation distribution and biogeochemistry, and couples vegetation distribution directly to biogeochemistry. Model inputs consist of latitude, soil texture class, and monthly climate (temperature, precipitation, and sunshine) data on a 0.5 degrees grid. Ecophysiological constraints determine which plant functional types (PFTs) may potentially occur. A coupled carbon and water flux model is then used to calculate, for each PFT, the leaf area index (LAI) that maximizes net primary production (NPP), subject to the constraint that NPP must be sufficient to maintain this LAI. Competition between PFTs is simulated by using the optimal NPP of each PFT as an index of competitiveness, with additional rules to approximate the dynamic equilibrium between natural disturbance and succession driven by light competition. Model output consists of a quantitative vegetation state description in terms of the dominant PFT, secondary PFTs present, and the total LAI and NPP for the ecosystem. Canopy conductance is treated as a function of the calculated optimal photosynthetic rate and water stress. Regional evapotranspiration is calculated as a function of canopy conductance, equilibrium evapotranspiration rate, and soil moisture using a simple planetary boundary layer parameterization. This scheme results in a two-way coupling of the carbon and water fluxes through canopy conductance, allowing simulation of the response of photosynthesis, stomatal conductance, and leaf area to environmental factors including atmospheric CO2. Comparison with the mapped distribution of global vegetation shows that the model successfully reproduces the broad-scale patterns in potential natural vegetation distribution. Comparison with NPP measurements, and with an FPAR (fractional absorbed photosynthetically active radiation) climatology based on remotely sensed greenness measurements, provides further checks on the model's internal logic. The model is envisaged as a tool for integrated analysis of the impacts of changes in climate and CO2 on ecosystem structure and function. (Less)
971 citations
Journal Article•
TL;DR: In this paper, the search for a piecewise quadratic Lyapunov function is formulated as a convex optimization problem in terms of linear matrix inequalities, and the relation to frequency domain methods such as the circle and Popov criteria is explained.
Abstract: This paper presents a computational approach to stability analysis of nonlinear and hybrid systems. The search for a piecewise quadratic Lyapunov function is formulated as a convex optimization problem in terms of linear matrix inequalities. The relation to frequency domain methods such as the circle and Popov criteria is explained. Several examples are included to demonstrate the flexibility and power of the approach.
TL;DR: It is suggested that MOZ may represent a chromatin-associated acetyltransferase, and the possibility that a dominant MOZ–CBP fusion protein could mediate leukaemogenesis via aberrant chromatin acetylation is raised.
Abstract: The recurrent translocation t(8;16)(p11;p13) is a cytogenetic hallmark for the M4/M5 subtype of acute myeloid leukaemia. Here we identify the breakpoint-associated genes. Positional cloning on chromosome 16 implicates the CREB-binding protein (CBP), a transcriptional adaptor/coactivator protein. At the chromosome 8 breakpoint we identify a novel gene, MOZ, which encodes a 2,004-amino-acid protein characterized by two C4HC3 zinc fingers and a single C2HC zinc finger in conjunction with a putative acetyltransferase signature. In-frame MOZ-CBP fusion transcripts combine the MOZ finger motifs and putative acetyltransferase domain with a largely intact CBP. We suggest that MOZ may represent a chromatin-associated acetyltransferase, and raise the possibility that a dominant MOZ-CBP fusion protein could mediate leukaemogenesis via aberrant chromatin acetylation.
TL;DR: Results show that type 1 fimbriae in the genetic background of a uropathogenic strain contribute to the pathogenesis of E. coli in the urinary tract.
Abstract: Type 1 fimbriae are adhesion organelles expressed by many Gram-negative bacteria. They facilitate adherence to mucosal surfaces and inflammatory cells in vitro, but their contribution to virulence has not been defined. This study presents evidence that type 1 fimbriae increase the virulence of Escherichia coli for the urinary tract by promoting bacterial persistence and enhancing the inflammatory response to infection. In a clinical study, we observed that disease severity was greater in children infected with E. coli O1:K1:H7 isolates expressing type 1 fimbriae than in those infected with type 1 negative isolates of the same serotype. The E. coli O1:K1:H7 isolates had the same electrophoretic type, were hemolysin-negative, expressed P fimbriae, and carried the fim DNA sequences. When tested in a mouse urinary tract infection model, the type 1-positive E. coli O1:K1:H7 isolates survived in higher numbers, and induced a greater neutrophil influx into the urine, than O1:K1:H7 type 1-negative isolates. To confirm a role of type 1 fimbriae, a fimH null mutant (CN1016) was constructed from an O1:K1:H7 type 1-positive parent. E. coli CN1016 had reduced survival and inflammatogenicity in the mouse urinary tract infection model. E. coli CN1016 reconstituted with type 1 fimbriae (E. coli CN1018) had restored virulence similar to that of the wild-type parent strain. These results show that type 1 fimbriae in the genetic background of a uropathogenic strain contribute to the pathogenesis of E. coli in the urinary tract.
TL;DR: It is demonstrated that female great reed warblers obtain EPFs from neighbouring males with larger song repertoires than their social mate, and the relative post-fledging survival of offspring was positively correlated with their genetical fathers' song repertoire size.
Abstract: IN many birds, females copulate with males other than their social mate, resulting in extra-pair fertilizations (EPFs)1–7. It is still unknown, however, why females seek EPFs7,8. In one study, males that accounted for most EPFs had higher survival6, but neither the characteristics revealing male quality nor the benefits accruing to females selecting attractive males were identified. Great reed warblers, Acrocephalus arundinaceus, are socially polygynous, and females base their mate choice on territory quality9 and song-repertoire size10, both of which predict harem size and reproductive success11,12. By DNA fingerprinting13, we demonstrate that female great reed warblers obtain EPFs from neighbouring males with larger song repertoires than their social mate. In addition, the relative post-fledging survival of offspring was positively correlated with their genetical fathers' song repertoire size. These data support the hypothesis that females, by engaging in extra-pair fertilizations, seek genetic benefits for their offspring7,8.
TL;DR: The stability and low cost of molecularly imprinted polymers make them advantageous for use in analysis as well as in industrial scale production and application.
Abstract: The technique of molecular imprinting allows the formation of specific recognition and catalytic sites in macromolecules by the use of templates. Molecularly imprinted polymers have been applied in an increasing number of applications where molecular binding events are of interest. These include (i) the use of molecularly imprinted polymers as tailor-made separation materials, (ii) antibody and receptor binding site mimics in recognition and assay systems, (iii) enzyme mimics for catalytic applications, and (iv) recognition elements in bio-sensors. The stability and low cost of molecularly imprinted polymers make them advantageous for use in analysis as well as in industrial scale production and application.
TL;DR: In this article, a method for the objective biomization of pollen samples based on fuzzy logic is described, where the pollen sample is assigned to the biome to which it has the highest affinity subject to a tie-breaking rule.
Abstract: Biome models allow the results of experiments with atmospheric general circulation models to be translated into global maps of potential natural vegetation. The use of biome models as a diagnostic tool for palaeoclimate simulations can yield maps that are directly comparable with palaeoecological (pollen and plant macrofossil) records provided these records are “biomized”, i.e. assigned to biomes in a consistent way. This article describes a method for the objective biomization of pollen samples based on fuzzy logic. Pollen types (taxa) are assigned to one or more plant functional types (PFTs), then affinity scores are calculated for each biome in turn based on its list of characteristic PFTs. The pollen sample is assigned to the biome to which it has the highest affinity, subject to a tie-breaking rule. Modern pollen data from surface samples, reflecting present vegetation across Europe, are used to validate the method. Pollen data from dated sediment cores are then used to reconstruct European vegetation patterns for 6 ka. The reconstruction shows systematic differences from present that are consistent with previous interpretations. The method has proved robust with respect to human impacts on vegetation, and provides a rational way to interpret combinations of pollen types that do not have present-day analogs. The method demands minimal prior information and is therefore equally suitable for use in other regions with richer floras, and/or lower densities of available modern and fossil pollen samples, than Europe.
TL;DR: In this article, the authors examined the effect on soil fungal:bacterial biomass ratios of withholding fertiliser, lime, and sheep-grazing from reseeded upland grassland.
Abstract: In this study we examined the effect on soil fungal:bacterial biomass ratios of withholding fertiliser, lime, and sheep-grazing from reseeded upland grassland. The cessation of fertiliser applications on limed and grazed grassland resulted in a reduction in soil pH from 5.4 to 5.1. The cessation of fertiliser applications and liming on grazed grassland resulted in a fall in pH from 5.4 to 4.7, whereas withholding fertiliser and lime and the removal of grazing resulted in a further reduction to pH 4.5. Substrate-induced respiration was reduced in the unfertilised grazed (21%; P<0.01) and unfertilised ungrazed (36%; P<0.001) treatments. Bacterial substrate-induced respiration and bacterial fatty acids were unaffected by the treatments. The relative abundance of the fungal fatty acid 18:2ω6 increased by 39 and 72% (P<0.05) in the limed grazed and unfertilised grazed treatments, respectively. Fungal substrate-induced respiration increased in the limed grazed (18%) and unfertilised grazed (65%; P<0.05) treatments. The ratio of 18:2ω6: bacterial fatty acids was correlated with the ratio of fungal:bacterial substrate-induced respiration (r=0.69; P<0.001).
TL;DR: Women with familial thrombophilia, especially those with combined defects or antithrombin deficiency, have an increased risk of fetal loss, particularly stillbirth.
TL;DR: From the 'Channg Cross and Westminster Medical School London UK IRCCS Maggiore Hospital, Milan Italy, Beth Israel Hospital, Boston USA, and the 'Institute of Thrombosis and Hemostasis Tel Hashomer, Israel.
Abstract: From the 'Channg Cross and Westminster Medical School London UK IRCCS Maggiore Hospital, Milan Italy Beth Israel Hospital, Boston USA, \"University Hospital Leiden The Netherlands Research Centre of Medical Genetics Moscow The Russian Federation, WHO, Switzerland, Chnstian Medical College Hospital Vellore India University of Lund, Malmo Sweden 'Institute of Clinical Genetics Moscow The Russian Federation, Washmgton University, St Louis, USA, \"Institute of Thrombosis and Hemostasis Tel Hashomer, Israel
TL;DR: There is a very large variation in how the experts graded the impact of various possible factors in the caries decline seen in many westernized countries over the past 3 decades.
Abstract: The aim of this paper was to describe what experts of today believe are the main reasons explaining the caries decline seen in many westernized countries over the past 3 decades. We have collected the views of a number of international experts, trying to answer the specific question “What are the main reasons why 20-25-year-old persons have less caries nowadays, compared to 30 years ago?”. A questionnaire was mailed to 55 experts with a number of thinkable explanations to be scored according to a predetermined scale. The 25 items were divided into main groups under the heading of diet, fluorides. plaque, saliva, dentist/dental materials and other factors. The experts were asked to think of a specific country or area, and also to specify whether the chosen area had water fluoridation or not. The main finding of our study, based on a 95% response rate, was that there is a very large variation in how the experts graded the impact of various possible factors. For the use of fluoride toothpaste, there was a clear agreement of a definite positive effect.
TL;DR: A 150-year-long cooling in the early Preboreal, associated with rising Δ14C values, is evident in all records and indicates an ocean ventilation change, and box-model calculations suggest that they all may have been the result of increased freshwater forcing that inhibited the strength of the North Atlantic heat conveyor.
Abstract: On the basis of synchronization of three carbon-14 (C-14)-dated lacustrine sequences from Sweden With tree ring and ice core records, the absolute age of the Younger Dryas-Preboreal climatic shift was determined to be 11,450 to 11,390 +/- 80 years before the present. A 150-year-long cooling in the early Preboreal, associated with rising Delta(14)C values, is evident in all records and indicates an ocean ventilation change. This cooling is similar to earlier deglacial coolings, and box-model calculations suggest that they all may have been the result of increased freshwater forcing that inhibited the strength of the North Atlantic heat conveyor, although the Younger Dryas may have begun as an anomalous meltwater event.
TL;DR: In this paper, the peroxidase-modified amperometric electrodes have been widely studied and developed, not only because of hydrogen and organic peroxides are important analytes but also because of the key role of hydrogen peroxide detection in coupled enzyme systems, in which the peroxide is formed as the product of the enzymatic reaction.
TL;DR: It is concluded that cystatin C is mainly removed from the extracellular fluid by the kidneys, practically freely filtered in the glomeruli, and completely absorbed and rapidly broken down by the proximal tubular cells.
Abstract: Serum cystatin C concentration correlates negatively with glomerular filtration rate as well as or better than that of serum creatinine, suggesting a constant formation, and elimination from extracellular fluid mainly by glomerular filtration It is not known, however, how well the renal plasma clearance of this 13-kDa basic polypeptide matches the glomerular filtration rate This was investigated in rats during control conditions and after reduced renal perfusion pressure 125I-cystatin C and an indicator for glomerular filtration (51Cr-EDTA or 131I-aprotinin) were injected intravenously The renal accumulation and urinary excretion of the tracers were recorded in periods of 25 to 200 min The renal plasma clearance of 125I-cystatin C (Ccy) based on the renal content of 125I correlated well with the glomerular filtration rate (Ccr-edta) in periods up to 6 min; ie Ccy=094 × Ccr-EDTA, r=099 Less than 05% of the filtered amount appeared in the urine During more prolonged periods, Ccy increasingly u
TL;DR: A suspension polymerization technique suitable for molecular imprinting is described, based on the use of a liquid perfluorocarbon as the dispersing phase, which produces polymer beads, with almost quantitative yield, which can be used after only a simple washing step.
Abstract: A suspension polymerization technique suitable for molecular imprinting is described, based on the use of a liquid perfluorocarbon as the dispersing phase. This dispersant does not interfere with the interactions between functional monomers and print molecules required for the recognition process during molecular imprinting. The method produces polymer beads, with almost quantitative yield, which can be used after only a simple washing step. An acrylate polymer with perfluorocarbon and poly(oxyethylene) ester groups was used to stabilize an emulsion of functional monomer, cross-linker, print molecule, initiator, and porogenic solvent in perfluoro(methylcyclohexane). Initiation of polymerization by UV irradiation resulted in polymer beads. The average bead size could be controlled between about 50 and 5 μm by varying the amount of stabilizing polymer. SEM of the beads indicated spherical particles with morphology typical of beads made by suspension polymerization. The technique was applicable to a range of...
15 Apr 1996
TL;DR: A new VLSI architecture for a real-time pipeline FFT processor is proposed, derived by integrating a twiddle factor decomposition technique in the divide-and-conquer approach, which has the same multiplicative complexity as the radix-4 algorithm, but retains the butterfly structure of the Radix-2 algorithm.
Abstract: A new VLSI architecture for a real-time pipeline FFT processor is proposed. A hardware-oriented radix-2/sup 2/ algorithm is derived by integrating a twiddle factor decomposition technique in the divide-and-conquer approach. The radix-2/sup 2/ algorithm has the same multiplicative complexity as the radix-4 algorithm, but retains the butterfly structure of the radix-2 algorithm. The single-path delay-feedback architecture is used to exploit the spatial regularity in the signal flow graph of the algorithm. For length-N DFT computation, the hardware requirement of the proposed architecture is minimal on both dominant components: log/sub 4/N-1 complexity multipliers and N-1 complexity data memory. The validity and efficiency of the architecture have been verified by simulation in the hardware description language VHDL.
TL;DR: It is concluded that abdominal obesity, insulin resistance, and decreased resting metabolic rate are characteristic features of first-degree relatives of patients with NIDDM and that the decrease in resting metabolic rates is partially related to the degree of abdominal obesity.
Abstract: Although a strong genetic susceptibility has been established for NIDDM and a maternal transmission of the disease predominates in some populations, a relationship between parental diabetes status and metabolic abnormalities in nondiabetic offspring has not been shown in humans. To address this question, we studied 2,152 first-degree relatives of patients with NIDDM (FH+) and 528 age- and weight-matched spouses without a family history of NIDDM (FH−) in Western Finland (the Botnia study). A subset of the subjects underwent a euglycemic insulin clamp combined with indirect calorimetry to measure insulin sensitivity and energy expenditure. Despite similar amounts of total body fat, persons with a family history of NIDDM had a greater waist-to-hip ratio (WHR) than spouses without a family history of diabetes ( P < 0.003). They also had a decreased resting metabolic rate ( P = 0.005), but this difference disappeared when adjusted for the difference in WHR. Insulin-stimulated glucose metabolism ( P = 0.002), particularly nonoxidative glucose metabolism ( P = 0.009), was reduced in FH+ compared with FH− subjects, and this difference remained after adjustment for WHR. A parental history of NIDDM influenced the insulin response to the oral glucose load, with male offspring of diabetic mothers showing the lowest insulin values ( P = 0.011). Moreover, a parental effect was also observed on HDL and HDL2 cholesterol concentrations with female offspring of diabetic mothers showing lower values than female offspring of diabetic fathers (both P < 0.002). We conclude that abdominal obesity, insulin resistance, and decreased resting metabolic rate are characteristic features of first-degree relatives of patients with NIDDM and that the decrease in resting metabolic rate is partially related to the degree of abdominal obesity. A sex-specific paternal effect was observed on insulin and HDL cholesterol concentrations. Therefore, one has to consider the possibility of unprecedented maternal or paternal inheritance of different NIDDM phenotypes.
TL;DR: A range of observed physiological responses to temperature and CO2 can be understood as consequences of the optimization of canopy net photosynthesis, which leads to reasonable values for the maximum (unstressed) light-use efficiency of gross and net primary production of C-3 plants at current ambient CO2.
Abstract: 1. Net primary production (NPP) by terrestrial ecosystems appears to be proportional to absorbed photosynthetically active radiation (APAR) on a seasonal and annual basis. This observation has been used in 'diagnostic' models that estimate NPP from remotely sensed vegetation indices. In 'prognostic' process-based models carbon fluxes are more commonly integrated with respect to leaf area index assuming invariant leaf photosynthetic parameters. This approach does not lead to a proportional relationship between NPP and APAR. However, leaf nitrogen content and Rubisco activity are known to vary seasonally and with canopy position, and there is evidence that this variation takes place in such a way as to nearly optimize total canopy net photosynthesis. 2. Using standard formulations for the instantaneous response of leaf net photosynthesis to APAR, we show that the optimized canopy net photosynthesis is proportional to APAR. This theory leads to reasonable values for the maximum (unstressed) light-use efficiency of gross and net primary production of C-3 plants at current ambient CO2, comparable with empirical estimates for agricultural crops and forest plantations. 3. By relating the standard formulations to the Collatz-Farquhar model of photosynthesis, we show that a range of observed physiological responses to temperature and CO2 can be understood as consequences of the optimization. These responses include the CO2 fertilization response and stomatal closure in C-3 plants, the increase of leaf N concentration with decreasing growing season temperature, and the downward acclimation of leaf respiration and N content with increasing ambient CO2. The theory provides a way to integrate diverse experimental observations into a general framework for modelling terrestrial primary production. (Less)
TL;DR: In this article, the effects of Zn contamination on the microbial community structure of a forest humus and an arable soil, as estimated by phospholipid fatty acid (PLFA) analysis, were followed during 18 months.
Abstract: The effects of Zn contamination on the microbial community structure of a forest humus and an arable soil, as estimated by phospholipid fatty acid (PLFA) analysis, were followed during 18 months. The soils were contaminated at 10 different metal concentrations and incubated in plastic jars at 22°C. In both soils effects of heavy metal contamination could be detected after 2 weeks. Qualitatively similar changes in the PLFA pattern were found at the later sampling occasions, although the changes became more pronounced with prolonged incubation. In the forest soil the double-unsaturated 18:2ω6, indicating fungi, increased proportionally due to the metal amendment, while there was a strong negative effect of incubation on the fungal biomass in all samples of this soil type. In the arable soil 18:2ω6 showed a strong increase in response to the Zn pollution. As in the forest soil, incubation decreased the mol% of 18:2ω6, although the effect was less pronounced than in the forest soil. The proportions of several individual bacterial PLFAs changed in both soils due to the treatments, indicating shifts within the bacterial community in the soils, but these shifts could not be interpreted in terms of changes in the proportional abundance of specific taxonomic groups of bacteria. The ratio of 16:1ω7t-to-16:1ω7c, which has been proposed as a starvation index, increased in the forest soil due to Zn contamination. In the high-metal samples this ratio decreased during incubation, while it remained unchanged in the uncontaminated control. In the arable soil no clear effect was found on the trans-to-cis ratio either in response to metal contamination or to incubation. The ATP content decreased during incubation. Little or no effect was found on the total amount of PLFAs or on the lipid phosphate content, except after 18 months when these biomass measurements decreased.
TL;DR: The induction of the proteinase-activated receptor 2 by cytokine treatment supports the concept of PAR-2 involvement in the acute inflammatory response.