Low Initial Population Research Articles

Optimal scheduling strategy of electric vehicle based on improved NSGA-III algorithm.

Aiming at the problem of load increase in distribution network and low satisfaction of vehicle owners caused by disorderly charging of electric vehicles, an optimal scheduling model of electric vehicles considering the comprehensive satisfaction of vehicle owners is proposed. In this model, the dynamic electricity price and charging and discharging state of electric vehicles are taken as decision variables, and the income of electric vehicle charging stations, the comprehensive satisfaction of vehicle owners considering economic benefits and the load fluctuation of electric vehicles are taken as optimization objectives. The improved NSGA-III algorithm (DJM-NSGA-III) based on dynamic opposition-based learning strategy, Jaya algorithm and Manhattan distance is used to solve the problems of low initial population quality, easy to fall into local optimal solution and ignoring potential optimal solution when NSGA-III algorithm is used to solve the multi-objective and high-dimensional scheduling model. The experimental results show that the proposed method can improve the owner's satisfaction while improving the income of the charging station, effectively alleviate the conflict of interest between the two, and maintain the safe and stable operation of the distribution network.

Influence of the storage temperature of raw sheep milk on the spoilage potential of Pseudomonas spp.

Due to their quality, high yield and nutritional value, sheep dairy products have been gaining market space and attracting new producers. Pseudomonas spp. is the most common psychrotrophic genus present in bovine refrigerated raw milk and is characterized by intense lipoproteolytic activity. Metalloprotease aprX is one of the enzymes produced by Pseudomonas spp. which has great industrial importance, since it has specific activity in the deterioration of casein, resulting in significant changes in physicochemical properties and sensorial characteristics of raw milk and dairy products. The aim of this study was to observe the occurrence of Pseudomonas spp. in raw sheep milk and evaluate the influence of storage temperature on the spoilage potential of the strains. Raw sheep milk samples were stored at 4 °C or 9 °C (72 h) and plated in Pseudomonas Agar Base supplemented with CFC (25 ºC / 48 h). The isolates characteristic of Pseudomonas had their genus, species (P. putida, P. fluorescens and P. aeruginosa), and presence of gene aprX confirmed by Polymerase Chain Reaction (PCR). The lipoproteolytic capacity and the spoilage potential of the isolates were evaluated in Milk Agar (10%) and Tributyrin Agar Base (1%) (21 °C / 72 h). Initial (2 h) populations of Pseudomonas spp. ranged from 1.0 to 4.2 log CFU/mL; after 72 h, the values observed in milk samples stored at 9 °C (3.0–7.0 log CFU/mL) were higher than those obtained in samples at 4 °C (1.6–6.0 log CFU/mL). A total of 255 strains of Pseudomonas spp. were isolated: 30.2% (77) from milk stored at 4 °C and 69.8% (178) from milk at 9 °C. At both temperatures, P. fluorescens was predominant, followed by P. putida. P. aeruginosa strains, isolated only from samples stored at 9 °C, showed high lipoproteolytic capacity and were characterized by higher proteolytic potential than lipolytic. P. fluorescens was the only species to present high proteolytic (halos > 2 cm) potential. Considering a single storage temperature (4 °C and 9 °C), only P. fluorescens showed higher proteolytic potential than lipolytic. The aprX gene was predominant in P. fluorescens and P. putida isolates (4 °C and 9 °C); strains obtained from milk stored at 4 °C showed higher proteolytic potential than those isolated from milk at 9 °C. All strains of P. fluorescens and only 46.42% of P. putida presented proteolytic capacity at 9 °C. The aprX gene was observed in all P. aeruginosa strains, but only 95.65% of them showed proteolytic capacity. The lipolytic potentials of P. fluorescens and P. putida were not influenced by milk storage temperature. P. fluorescens was the only species to present high lipolytic potential. P. putida isolated from milk at 9 °C was the only species to present higher lipolytic potential than proteolytic. According to the microbiota and the storage temperature, there may be a predominance of proteolytic or lipolytic enzymes in milk and consequently, defects in sheep dairy products. It should also be considered that most of the isolates of Pseudomonas spp. presented lipoproteolytic capacity, which emphasizes the importance of low initial populations of this microorganism in raw sheep-chilled milk, mainly when used in the production of dairy products.

Sacubitril/Valsartan Treatment in Heart Failure Increases The Left Ventricular Ejection Fraction: A Bayesian Analysis

Introduction: Heart failure is an important leading cause of mortality and morbidity despite optimal medical treatment and device therapy. Sacubitril/valsartan, a first-generation drug, was approved to use heart failure treatment recently. There are limited studies on the relationship between sacubitril/valsartan and left ventricular contraction. In our study, we aimed to evaluate the changes in left ventricular ejection fraction (LVEF) after sacubitril/valsartan treatment. Patients and Methods: Fifty-two patients with heart failure and reduced ejection fraction (HFrEF) were enrolled in this study. The baseline demographic, clinical, and echocardiographic characteristics of 52 patients were compared using the Bayesian method. Results: Fifty-two patients with heart failure and reduced ejection fraction (HFrEF) were included in the final analysis (66.2 ± 9.3 years, 69.2% male). Sacubitril/valsartan initial dose was low in 44.2% of patients, and intermediate in 55.8%. In the low initial dose population, the increase in absolute LVEF was 3.87 (95% HDI 1.53-6.20) and in the intermediate initial dose population, the increase in absolute LVEF was 5.89 (95% HDI 4.18-7.61). In the female population, the increase in absolute LVEF was 5.56 (95% HDI 3.49-7.63) and in the male population 4.75 (95% HDI 2.91-6.58) respectively. Conclusion: In this study, we demonstrated that sacubitril/valsartan is associated with increased LVEF regardless of baseline clinical characteristics.

A theoretical framework for multi‐species range expansion in spatially heterogeneous landscapes

Range expansion is the spatial spread of a population into previously unoccupied regions. Understanding range expansion is important for the study and successful management of ecosystems, with applications ranging from controlling bacterial biofilm formation in industrial and medical environments to large scale conservation programmes for species undergoing climate‐change induced habitat disruption. During range expansion, species typically encounter competitors. Moreover, the spatial environment into which expansion takes place is almost always heterogeneous. Nevertheless, the impact of competition and spatial landscape heterogeneities on range expansion remains understudied. In this paper we present a theoretical framework comprising two competing generic species undergoing range expansion and use it to investigate the impact of spatial landscape heterogeneities on range expansion with a particular focus on its effect on competition dynamics. We reveal that the area covered by range expansion is highly variable due to the landscape heterogeneities. Moreover, we report significant variability in competitive outcome (relative abundance of a focal species), but determine that this is induced by low initial population densities and is independent of landscape heterogeneities. We further show that both area covered by range expansion and competitive outcome can be accurately predicted by a Voronoi tessellation with respect to an appropriate metric, which only requires information on the spatial landscape and the response of each species to that landscape. Finally, we reveal that if species interact antagonistically during range expansion, the dominant mode of competition depends on the initial population density; antagonistic actions determine competitive outcome if the initial population density is high, but competition for space is the dominant mode of competition if the initial population density is low. These findings enhance our understanding of how competition for space and antagonistic interactions affect range expansion in spatially heterogeneous environments and provide a predictive tool for future species‐specific approaches.

Growth behavior of low populations of Listeria monocytogenes on fresh-cut mango, melon and papaya under different storage temperatures

The growth behavior of Listeria monocytogenes low population (1–4 cells/sample) on fresh-cut mango, melon, papaya and fruit mix stored at 4, 8, 12 and 16 °C was evaluated over 10 days. Mango showed the lowest counts for L. monocytogenes during 10 days regardless of storage temperature (<1.7 log cfu.g−1). Melon supported high bacterial growth over 10 days, reaching 5 log cfu.g−1 at 16 °C. Both the fruit and storage temperature influenced the Listeria low population growth potential (δ). Cumulative frequency distribution of L. monocytogenes showed that after 10 days, 100% of fresh-cut fruits and fruit mix stored at 4 °C remained ≤2 log cfu.g−1, while at 12 and 16 °C 100% of melon, papaya and fruit mix samples exceeded this limit. At 8 °C, 100% of mango and fruit mix samples remained below this limit after 10 days, whereas 100% of melon and papaya reached it after 7 days. Results indicate 4 °C as the ideal to store safely fresh-cut mango, melon, papaya and fruit mix for 10 days. Besides, 8 °C can also be an option, but not for melon and papaya. Findings highlight the ability of L. monocytogenes to survive and grow in fresh-cut fruits even at a very low initial population levels.

Investigating the Impact of Root-Lesion Nematodes (Pratylenchus thornei) and Crown Rot (Fusarium pseudograminearum) on Diverse Cereal Cultivars in a Conservation Farming System

In two experiments on a farm practicing conservation agriculture, the grain yield of a range of wheat cultivars was significantly (p &lt; 0.001) negatively related to the post-harvest population densities of Pratylenchus thornei in the soil profile to 45 cm depth. In a third and fourth experiment with different rotations, methyl bromide fumigation significantly (p &lt; 0.05) decreased (a) a low initial population density of P. thornei in the soil profile to 90 cm depth and (b) a high initial population of P. thornei to 45 cm depth, and a medium level of the crown rot fungus, Fusarium pseudograminearum, at 0–15 cm depth to a low level. For a range of wheat and durum cultivars, grain yield and response to fumigation were highly significantly (p &lt; 0.001) related to (a) the P. thornei tolerance index of the cultivars in the third experiment, and (b) to both the P. thornei tolerance index and the crown rot resistance index in the fourth experiment. In the latter, grain yield was significantly (p &lt; 0.001) positively related to biomass at anthesis and negatively related to percentage whiteheads at grain fill growth stage. One barley cultivar was more tolerant to both diseases than the wheat and durum cultivars. Crop rotation, utilizing crop cultivars resistant and tolerant to both P. thornei and F. pseudograminearum, is key to success for conservation farming in this region.

What goes up must come down – why high fecundity orchids challenge conservation beliefs

The life history of orchids is relatively well understood qualitatively, but quantifying this model and extracting a conservation message remains challenging. Orchid conservation requires the means to assess a species' vulnerability, and to restore populations that have lost numbers or range. In this study, we examine orchid population dynamics and, by extension, a large number of similar organisms with Type-III survival strategy: high fecundity and high mortality at early stages of life. By assuming a balance between fecundity and mortality, we establish a theoretical dynamic population model for orchid species, which also runs under scenarios of high environmental variability for various levels of fecundity. Our findings show that population variability increases mainly through survival variability. High fecundity acts as an amplifier of environmental variability and can cause populations to reach levels where extinction is a threat. Thus, extinction probability can paradoxically rise with increasing fecundity. In addition, at high fecundities, the extinction probability of orchids and other organisms characterized by very high fecundity and high pre-reproductive mortality may be relatively insensitive to initial population size, compared with organisms with low fecundity and mortality. The high fecundities of orchids do not shield them from extinction but may cause them to be more vulnerable to extinction. Changes in the environment have even greater impact than low initial population sizes.

P.005 Traumatic-like fear memory recall causes persistent morphine seeking behaviour in mice

The life history of orchids is relatively well understood qualitatively, but quantifying this model and extracting a conservation message remains challenging. Orchid conservation requires the means to assess a species' vulnerability, and to restore populations that have lost numbers or range. In this study, we examine orchid population dynamics and, by extension, a large number of similar organisms with Type-III survival strategy: high fecundity and high mortality at early stages of life. By assuming a balance between fecundity and mortality, we establish a theoretical dynamic population model for orchid species, which also runs under scenarios of high environmental variability for various levels of fecundity. Our findings show that population variability increases mainly through survival variability. High fecundity acts as an amplifier of environmental variability and can cause populations to reach levels where extinction is a threat. Thus, extinction probability can paradoxically rise with increasing fecundity. In addition, at high fecundities, the extinction probability of orchids and other organisms characterized by very high fecundity and high pre-reproductive mortality may be relatively insensitive to initial population size, compared with organisms with low fecundity and mortality. The high fecundities of orchids do not shield them from extinction but may cause them to be more vulnerable to extinction. Changes in the environment have even greater impact than low initial population sizes.

The “pied de cuve” as an alternative way to manage indigenous fermentation: impact on the fermentative process and &lt;i&gt;Saccharomyces cerevisiae&lt;/i&gt; diversity

Winemakers are increasingly keen to limit the use of commercial yeasts in order to reduce oenological inputs. The preparation of an indigenous winery-made fermentation starter from grapes called ‘pied de cuve’ (PdC) is becoming popular, especially in organic farming systems. However, the implementation of the PdC method is still empirical and knowledge is lacking regarding the impact of PdC on S. cerevisiae diversity during alcoholic fermentation. In this study, the impact of PdC on S. cerevisiae genetic diversity and wine composition was evaluated at an industrial scale. Despite very low initial population level of S. cerevisiae before inoculation, the use of PdC was as efficient as Active Dry Yeast in terms of fermentation kinetics and chemical analyses on the resulting wines, except for one modality. At mid-fermentation, the diversity of S. cerevisiae strains was different depending on the PdC used, and was also different from that in the spontaneous fermentation with, in some cases, clonal expansion. Our results provide evidence that the use of PdC could secure the fermentation process more efficiently than spontaneous fermentation.

The "pied de cuve" as an alternative way to manage indigenous fermentation: impact on the fermentative process and Saccharomyces cerevisiae diversity

Winemakers are increasingly keen to limit the use of commercial yeasts in order to reduce oenological inputs. The preparation of an indigenous winery-made fermentation starter from grapes called ‘pied de cuve’ (PdC) is becoming popular, especially in organic farming systems. However, the implementation of the PdC method is still empirical and knowledge is lacking regarding the impact of PdC on S. cerevisiae diversity during alcoholic fermentation. In this study, the impact of PdC on S. cerevisiae genetic diversity and wine composition was evaluated at an industrial scale. Despite very low initial population level of S. cerevisiae before inoculation, the use of PdC was as efficient as Active Dry Yeast in terms of fermentation kinetics and chemical analyses on the resulting wines, except for one modality. At mid-fermentation, the diversity of S. cerevisiae strains was different depending on the PdC used, and was also different from that in the spontaneous fermentation with, in some cases, clonal expansion. Our results provide evidence that the use of PdC could secure the fermentation process more efficiently than spontaneous fermentation.

Spatially propagating activation of quorum sensing in Vibrio fischeri and the transition to low population density.

Bacteria communicate by secreting and detecting diffusible small molecule signals or pheromones. Using the local concentrations of these signals to regulate gene expression, individual cells can synchronize changes in phenotype population-wide, a behavior known as quorum sensing (QS). In unstirred media, the interplay between diffusion of signals, bacterial growth, and regulatory feedback can generate complex spatial and temporal patterns of expression of QS-controlled genes. Here we identify the parameters that allow a local signal to trigger a self-sustaining, traveling activation of QS behavior. Using the natural bioluminescence of wild-type Vibrio fischeri as a readout of its lux QS system, we measure the induction of a spreading QS response by a localized triggering stimulus in unstirred media. Our data show that a QS response propagates outward, sustained by positive feedback in synthesis of the diffusible signal, and that this response occurs only if the triggering stimulus exceeds a critical threshold. We also test how the autonomous or untriggered activation of the V. fischeri QS pathway changes at very low initial population densities. At the lowest population densities, clusters of cells do not transition to a self-sensing behavior, but rather remain in communication via signal diffusion until they reach sufficiently large size that their own growth slows. Our data, which are reproduced by simple growth and diffusion simulations, indicate that in part owing to bacterial growth behavior, natural QS systems can be characterized by long distance communication through signal diffusion even in very heterogeneous and spatially dispersed populations.

Experiment on obtaining an algologically pure culture of Tetraselmis viridis in non-sterile conditions

The possibility of obtaining an algologically pure culture of Tetraselmis viridis, grown on the Black Sea water in non-sterile conditions, was shown experimentally. Our experiments showed that at low initial population density of the culture after 1–3 days, there was an infection of the culture with blue-green species of microalgae (Oscillatoria sp.). Thrice repeated mechanical removal of blue-green microalgae cells by filtering the infected culture allowed obtaining an algologically pure culture of T. viridis. Under similar conditions of T. viridis cultivation, but with the initial addition of NaCl (15 g/l) to the nutrient medium aimed at increasing salinity to the Mediterranean level, there was no contamination of the culture.

Population imbalance, macroscopic tunneling and intermodal entanglement of two-mode Bose–Einstein condensate under the influence of dissipation process

In this paper, we study the dissipative dynamics of a system which is composed of two atomic Bose–Einstein condensates (BECs) interacting through the Josephson-like coupling. To model a more realistic physical system, the inevitable dissipation effect is considered via the interaction between the system and its environment, in particular, a thermal reservoir. In this respect, after introducing a proper Hamiltonian for the model, we analytically solve the corresponding quantum Heisenberg–Langevin equations and then obtain explicit analytical expressions for population imbalance, macroscopic tunneling current and intermodal entanglement. Generally, the dynamics of the system is very sensitive to the chosen values of tunneling coupling strength, initial population as well as the characteristics of interaction between the system and its reservoirs. Also, the time evolution of the above-mentioned physical quantities shows oscillatory decaying behavior where the frequency of oscillations depends on the strength of tunneling interaction between the two subsystems. The oscillatory pattern of population imbalance and tunneling current is more regular in comparison with the intermodal entanglement. Although the system is always separable for low initial population, we show that it tends to an entangled state as its initial population is increased. In particular, the amount and the time interval of the entanglement can be effectively controlled via the dissipation parameter. Also, to get an insight into the effect of nonlinear interaction on the behavior of dynamical evolution of the considered system, we numerically investigate the population imbalance in the absence and presence of such interactions. A qualitative comparison shows that the previous theoretical works and numerical simulations confirm our obtained results.

Characterising seasonal influenza epidemiology using primary care surveillance data.

Understanding the epidemiology of seasonal influenza is critical for healthcare resource allocation and early detection of anomalous seasons. It can be challenging to obtain high-quality data of influenza cases specifically, as clinical presentations with influenza-like symptoms may instead be cases of one of a number of alternate respiratory viruses. We use a new dataset of confirmed influenza virological data from 2011-2016, along with high-quality denominators informing a hierarchical observation process, to model seasonal influenza dynamics in New South Wales, Australia. We use approximate Bayesian computation to estimate parameters in a climate-driven stochastic epidemic model, including the basic reproduction number R0, the proportion of the population susceptible to the circulating strain at the beginning of the season, and the probability an infected individual seeks treatment. We conclude that R0 and initial population susceptibility were strongly related, emphasising the challenges of identifying these parameters. Relatively high R0 values alongside low initial population susceptibility were among the results most consistent with these data. Our results reinforce the importance of distinguishing between R0 and the effective reproduction number (Re) in modelling studies.

Looking for variable molecular markers in the chestnut gall wasp Dryocosmus kuriphilus: first comparison across genes

The quick spread of the chestnut gall wasp Dryocosmus kuriphilus in Europe constitutes an outstanding example of recent human-aided biological invasion with dramatic economic losses. We screened for the first time a set of five nuclear and mitochondrial genes from D. kuriphilus collected in the Iberian Peninsula, and compared the sequences with those available from the native and invasive range of the species. We found no genetic variability in Iberia in none of the five genes, moreover, the three genes compared with other European samples showed no variability either. We recorded four cytochrome b haplotypes in Europe; one was genuine mitochondrial DNA and the rest nuclear copies of mitDNA (numts), what stresses the need of careful in silico analyses. The numts formed a separate cluster in the gene tree and at least two of them might be orthologous, what suggests that the invasion might have started with more than one individual. Our results point at a low initial population size in Europe followed by a quick population growth. Future studies assessing the expansion of this pest should include a large number of sampling sites and use powerful nuclear markers (e. g. Single Nucleotide Polymorphisms) to detect genetic variability.

Influence of Algae Age and Population on the Response to TiO₂ Nanoparticles.

This work shows the influence of algae age (at the time of the exposure) and the initial algae population on the response of green algae Raphidocelis subcapitata to titanium dioxide nanoparticles (TiO2 NPs). The different algae age was obtained by changes in flow rate of continually stirred tank reactors prior to NP exposure. Increased algae age led to a decreased growth, variations in chlorophyll content, and an increased lipid peroxidation. Increased initial algae population (0.3−4.2 × 106 cells/mL) at a constant NP concentration (100 mg/L) caused a decline in the growth of algae. With increased initial algae population, the lipid peroxidation and chlorophyll both initially decreased and then increased. Lipid peroxidation had 4× the amount of the control at high and low initial population but, at mid-ranged initial population, had approximately half the control value. Chlorophyll a results also showed a similar trend. These results indicate that the physiological state of the algae is important for the toxicological effect of TiO2 NPs. The condition of algae and exposure regime must be considered in detail when assessing the toxicological response of NPs to algae.

Growth of Grapevine Rootlings in Soil from a Field Nursery Naturally Infested with Meloidogyne incognita and Rhizoctonia solani

Grapevine rootlings (V. vinifera cv. Colombard and V. champini cv. Ramsey) were grown in pots containing soil from a field nursery naturally infested with Meloidogyne incognita and Rhizoctonia solani. Vine growth in untreated soil with or without dilution using clean sand was compared with growth in soil subjected to a range of treatments including: disinfestation either by aerated steaming or by fumigation with methyl bromide, amendment with 1 % (w/w) corn-meal, or treatment with fungicides and/or fenamiphos. Vines grown in infested soil suffered root rot caused by R. soiani and galling caused by M. i11cog11ita. Both disinfestation treatments effectively prevented root rotting and galling, and increased the growth of Colombard but not Ramsey. Fenamiphos increased the growth of the nematode-susceptible Colombard but not Ramsey at a low initial population density of three juveniles per 200 g of soil. Nematode reproduction on Ramsey in the shadehouse and in the field nursery on other rootstocks regarded as being highly resistant to root-knot nematode was higher than previously reported with other South Australian Meloidogyne spp. populations. Soil dilution increased Colombard growth and amendment with corn-meal reduced nematode reproduction on both cultivars. Rhizoctonia solani caused root rot in both cultivars but quintozene and tolclofos-methyl increased root growth only of Ramsey. These fungicides and pencycuron reduced the severity of root rot; tolclofos-methyl was particularly effective in reducing the frequency of isolation of R. solani from roots. Potassium phosphite did not reduce root rot or increase root growth. Quintozene, tolclofos-methyl and pencycuron also inhibited nematode reproduction but these effects were not consistently observed in both cultivars. Most isolates of R. solani from grapevine roots belonged to anastomosis group 4. Field observations suggested that galled roots were more prone to infection by R. solani than ungalled roots.

Periodicity computation of generalized mathematical biology problems involving delay differential equations.

In this paper, we consider a low initial population model. Our aim is to study the periodicity computation of this model by using neutral differential equations, which are recognized in various studies including biology. We generalize the neutral Rayleigh equation for the third-order by exploiting the model of fractional calculus, in particular the Riemann–Liouville differential operator. We establish the existence and uniqueness of a periodic computational outcome. The technique depends on the continuation theorem of the coincidence degree theory. Besides, an example is presented to demonstrate the finding.

Recognising the value of all ‘restorative’ contributions

Recognising the value of all ‘restorative’ contributions

Práticas culturais na entressafra da soja para o controle de Pratylenchus brachyurus

Resumo: O objetivo deste trabalho foi avaliar o potencial de práticas culturais, adotadas na entressafra, para reduzir a população e os danos causados por Pratylenchus brachyurus em soja. Realizou-se um experimento em área naturalmente infestada, nas safras 2010/2011, 2011/2012 e 2012/2013, em Vera, MT. Os tratamentos foram: milheto (Pennisetum glaucum) 'ADR 7010' (2010/2011) e 'ADR 300' (nas entressafras seguintes); milho (Zea mays) 'BRS 1010' (2010/2011) e 'GNZ 2005' (nas entressafras seguintes); braquiária ruziziensis (Urochloa ruziziensis); capim-marandu (U. brizantha 'Marandu'); crotalária (Crotalaria ochroleuca); C. juncea; C. spectabilis; C. spectabilis + milheto 'ADR 300' (de 2011/2012 em diante); alqueive mecânico (duas gradagens + herbicida); pousio (sem controle de ervas daninhas); e testemunha (alqueive químico, com aplicação de herbicida). O alqueive mecânico, as crotalárias e C. spectabilis + milheto reduziram a população do nematoide antes da semeadura e nos estádios iniciais da soja. Após a colheita da soja, a população de nematoides não diferiu entre os tratamentos, o que indica que a multiplicação destes na cultura foi maior nos manejos com menor população inicial. O uso de C. spectabilis, milheto e C. spectabilis + milheto contribuíram para as maiores produtividades de soja. O cultivo de C. spectabilis, solteira ou consorciada ao milheto 'ADR 300', é a melhor opção para reduzir a população e os danos causados por P. brachyurus à soja na entressafra.