Pure Stocks Research Articles

Optimizing high-dimensional forestry for wood production and carbon sinks

Our model for optimizing stand-level wood production and carbon sinks includes individual-tree models for forest growth, an advanced model for soil carbon, detailed wood production economy, and an intertemporal objective for the value of wood production and carbon sinks/emissions. Carbon stocks include aboveground biomass and carbon in forest soil and in wood products. Optimization of the management regime, rotations and thinning timing, and type and intensity are carried out by reinforcement learning. Including the social price of carbon causes a regime switch from continuous cover forestry to clear-cuts, postponed lighter thinning, and a longer rotation, and with a high carbon price, to solutions with pure clear-cuts or solutions utilizing stands as pure carbon stocks. Carbon price has profound effects on stand values, and the bare land value may well exceed the value before a clear-cut. The total average carbon stock is maximized with harvest and a long rotation instead of “no harvesting”. Bioenergy, carbon capture, and storage (BECCS) always increases the value of wood production but not necessarily the value of carbon sinks. With BECCS, increasing carbon stocks in trees and forest soil remains optimal.

Molecular characterization of PMQR carrying bacteriophages in effluent discharge samples of Azerbaijan hospitals.

Quinolones are one of the most widely used drugs in medicine. Resistance to this agent has been increased significantly among the nosocomial isolates. The objective of this research was to study generalized transduction, as a potential mechanism for plasmid-mediated quinolone resistance (PMQR) genes acquisition among hospital effluent isolates. Discharge samples from hospital effluent were taken from four medical centers in Azerbaijan. Resident phages were enriched against resident enterobacterial hosts using standard phage enrichment protocols. Polymerase chain reaction (PCR) was used to examine phage stocks and bacterial isolates for the presence of PMQR determinants. All positive bacterial isolates for target genes were subjected to transduction assays. Restriction fragment length polymorphism (RFLP) profiles were determined for cluster analysis. A total of 55 pure phage stocks were prepared from 42 effluents. A total of 95 non-duplicated Gram-negative bacteria were isolated. Thirty-two EcoRV-RFLP profiles were determined for the 40 Escherichia coli phage stocks. Twenty-six of 40 (65%) E. coli phages were positive for qnrB (n = 15), qnrD (n = 7), qnrA (n = 3), and qnrC (n = 2) genes. A total of 34 (35.7%) bacterial isolates were recognized to have any PMQR genes including qnrB (n = 23), qnrD (n = 8), qnrA (n = 5), and qnrC (n = 3) genes. Present research provided a strong evidence for potential role of generalized transduction in persistence and circulation of PMQR genes in health care settings of Azerbaijan.

Production of Recombinant Hepatitis B virus (HBV) and Detection of HBV in Infected Human Liver Organoids.

The absence of long term, primary untransformed in vitro models that support hepatitis B virus (HBV) infection and replication have hampered HBV pre-clinical research, which was reflected in the absence of a curative therapy until recently. One of the limitations for in vitro HBV research has been the absence of high titer and pure recombinant HBV stocks, which, as we describe here, can be generated using simple, and reproducible protocols. In addition to infection of more conventional in vitro and in vivo liver model systems, recombinant high titer purified HBV stocks can also be used to efficiently infect differentiated human liver organoids, whose generation, maintenance, and infection is discussed in detail in a companion organoid protocol. Here, we also describe the protocols for the detection of specific viral read-outs, including HBV DNA in the supernatant of the cultures, covalently closed circular DNA (cccDNA) from intracellular DNA preparations, and HBV viral proteins and viral RNA, which can be detected within the cells, demonstrating the presence of a complete viral replication cycle in infected liver organoids. Although an evolving platform, the human liver organoid model system presents great potential as an exciting new tool to study HBV infection and progression to hepatocellular carcinoma (HCC) in primary cells, when combined with the use of high-titer and pure recombinant HBV stock for infection. Graphical abstract.

Comparison of highly pure rAAV9 vector stocks produced in suspension by PEI transfection or HSV infection reveals striking quantitative and qualitative differences

Recent clinical successes have propelled recombinant adeno-associated virus vectors (rAAV) to the center stage for human gene therapy applications. However, the exploding demand for high titers of highly pure rAAV vectors for clinical applications and market needs remains hindered by challenges met at the manufacturing stage. The production of rAAV by transfection in suspension cells remains one of the most commonly used production platforms. In this study, we describe our optimized protocol to produce rAAV by polyethyleneimine (PEI)-mediated transfection in suspension HEK293 cells, along with a side-by-side comparison to our high-performing system using the herpes simplex virus (HSV). Further, we detail a new, robust, and highly efficient downstream purification protocol compatible with both transfection and infection-based harvests that generated rAAV9 stocks of high purity. Our in-depth comparison revealed quantitative, qualitative, and biological differences between PEI-mediated transfection and HSV infection. The HSV production system yielded to higher rAAV vector titers, higher specific yields, and a higher percentage of full capsids than transfection. Furthermore, HSV-produced stocks had a significantly lower concentration of residual host cell proteins and helper DNA impurities, but contained detectable levels of HSV DNA. Importantly, the potency of PEI-produced and HSV-produced rAAV stocks were identical. Analyses of AAV Rep and Cap expression levels and replication showed that HSV-mediated production led to a lower expression of Rep and Cap, but increased levels of AAV genome replication. Our methodology enables high-yield, high purity rAAV production and a biological framework to improve transfection quality and yields by mimicking HSV-induced biological outcomes.

Genetic characterization and implications for conservation of the last autochthonous Mouflon population in Europe

Population genetic studies provide accurate information on population structure, connectivity, and hybridization. These are key elements to identify units for conservation and define wildlife management strategies aimed to maintain and restore biodiversity. The Mediterranean island of Sardinia hosts one of the last autochthonous mouflon populations, descending from the wild Neolithic ancestor. The first mouflon arrived in Sardinia ~ 7000 years ago and thrived across the island until the twentieth century, when anthropogenic factors led to population fragmentation. We analysed the three main allopatric Sardinian mouflon sub-populations, namely: the native sub-populations of Montes Forest and Mount Tonneri, and the reintroduced sub-population of Mount Lerno. We investigated the spatial genetic structure of the Sardinian mouflon based on the parallel analysis of 14 highly polymorphic microsatellite loci and mitochondrial D-loop sequences. The Montes Forest sub-population was found to harbour the ancestral haplotype in the phylogeny of European mouflon. We detected high levels of relatedness in all the sub-populations and a mitochondrial signature of hybridization between the Mount Lerno sub-population and domestic sheep. Our findings provide useful insights to protect such an invaluable genetic heritage from the risk of genetic depletion by promoting controlled inter-population exchange and drawing informed repopulation plans sourcing from genetically pure mouflon stocks.

Hot Potatoes: Overreaction to Extreme Negative Returns

Although it is well established that investors are willing to accept a negative premium for lottery-like stocks, it is puzzling that the opposite effect is not observed in stocks experiencing large daily losses. We find that stocks that experience large negative daily returns (MIN) also display large positive daily returns (MAX); therefore the MIN effect is subdued. Once stocks ranked as high-MAX within MIN deciles are removed, we find that MIN positively predicts future stock returns. More importantly, a strategy that buys pure high-MIN stocks and shorts pure high-MAX stocks generates superior returns compared to stand-alone MAX and/or MIN strategies.

Identification of Base Stock in Engine Oils by Near Infrared and Fluorescence Spectroscopies Coupled with Chemometrics

Engine oils are produced with a blend of almost 80% (w/w) base oils and 20% (w/w) of different additives. This study investigates, for the first time, the capabilities of NIR (Near Infrared) and EEM (Emission-Extraction Matrix) fluorescence spectroscopies coupled with chemometrics as low-cost, green and non-destructive methods in identifying the type of base stock into engine oil. In order to reach this goal, base stocks of different American Petroleum Institute (API) groups were analysed without any pre-treatment. PCA (Principal component analysis) performed on NIR and unfolded EEM spectra showed that samples form clusters according to their API groups and to chemical composition. PARAFAC (Parallel Factor Analysis) was also applied on 3-way fluorescence data and outcomes were consistent with PCA results. PLS-DA (Partial Least Squares Discriminant Analysis) was able to classify the base stock samples according to the API groups and satisfactory results were achieved: the correct prediction abilities on an external test set using NIR and EEM fluorescence spectroscopies were 87% and 85%, respectively. In addition, the determination of the base oil group at different gasoline engine oil performance levels was used as a method to evaluate the efficiency of the lubricants. Both spectroscopic methods appear to be fast and non-destructive to characterize the base stocks in analysing pure base stocks and engine oils with different performance levels.

Deformed wing virus: using reverse genetics to tackle unanswered questions about the most important viral pathogen of honey bees.

Deformed wing virus (DWV) is the most important viral pathogen of honey bees. It usually causes asymptomatic infections but, when vectored by the ectoparasitic mite Varroa destructor, it is responsible for the majority of overwintering colony losses globally. Although DWV was discovered four decades ago, research has been hampered by the absence of an in vitro cell culture system or the ability to culture pure stocks of the virus. The recent developments of reverse genetic systems for DWV go some way to addressing these limitations. They will allow the investigation of specific questions about strain variation, host tropism and pathogenesis to be answered, and are already being exploited to study tissue tropism and replication in Varroa and non-Apis pollinators. Three areas neatly illustrate the advances possible with reverse genetic approaches: (i) strain variation and recombination, in which reverse genetics has highlighted similarities rather than differences between virus strains; (ii) analysis of replication kinetics in both honey bees and Varroa, in studies that likely explain the near clonality of virus populations often reported; and (iii) pathogen spillover to non-Apis pollinators, using genetically tagged viruses to accurately monitor replication and infection.

Revisiting the Halal screening investments: the case of GCC stock markets

October 4, 2020 Revisiting the Halal screening investments: the case of GCC stock markets Khaled O. Alotaibi and Mohammad M. Hariri 14Issue This study provides a critical review of the issues associated with the screening of Islamic funds in the Gulf Cooperation Council (GCC) and questions the concept of Shariah-compliant (Halal) equity investment. Unlike prior relevant studies, the paper attempts to provide evidence as whether there is a necessity to invest in commingled Halal (CH) for a Halal diversified portfolio post the global financial crisis (GFC). This paper aims to explore how participants define and screen Shariah-compliant (Halal) investment, it particularly investigates whether pure Halal (PH) and commingled Halal (CH) equity investments are distinct or similar type of investments. The paper reports the findings of the semi-structured interviews with key participants in the Islamic funds industry mainly in Kuwait and other GCC countries. The findings from the interviews reveals that the Shariah-compliance equity investments are split into two different categories, namely: pure Halal (PH) and commingled Halal (CH) investments not as reported in the literature when measuring their screens or performance. Some interviewees seriously questioned the Shariah-compliance of CH stocks and thought that the fatwa that allows CH stocks should be revisited. The interviews findings highlight the need for harmonizing the Shariah screening criteria, and the development of accounting standards based on Islamic values rather than western ones to reflect the unique characteristics of Halal investments. Keywords: Islamic investment funds, Halal Investments, Shariah screening, Shariah-compliance investment, pure Halal stocks (PH), commingled Halal stocks (CH)

Corporate environmental performance and stock market performance: Indian evidence on disaggregated measure of sustainability

AbstractThe study addresses the emerging needs of green investing as it believes that the firms that are better equipped with mitigating and adapting climate change and its associated risk also perform better in the market. The construct of superior performance is based on the models linking environmental performance and financial performance in the literature. It aims to validate if those firms that are better equipped with adapting to climate change generate superior or equivalent market return as compared to blue chip firms, socially responsible firms, and general market portfolio. It further examines if market values disaggregated measure of sustainability, that is, environmental performance differently from others. Results of the study are consistent with the theoretical work suggesting that green investing is reflected in demand differences between green and nongreen stocks. It also establishes a link between alpha's and green investing. The results show that all green portfolios outperformed market at 1% significance level over 12‐year period and various subperiods. Results also indicate that investors of Indian stock market value pure green stocks more than those stocks that are screened out based on the criteria of corporate governance, employee relations, and other social factors along with environmental factor.

Utilization of rice wastewater as an alternative medium for growth and quality of Shiitake mushrooms (Lentinula edodes)

Multiplication of Shiitake (Lentinula edodes) as a pure breeding commonly uses Potato Dextrose Agar (PDA) as the medium. Further, the cost of its basic material, which relatively expensive needs an alternative medium to produce pure brood stocks for Shiitake and to reduce the cost of producing pure brood stocks such as utilizing rice wastewater. Rice wastewater known to have composition as complete as PDA. The research aimed to find the utilization of rice wastewater as Shiitake mycelial growth medium and determine the best concentration of rice wastewater medium on the growth rate and quality of Shiitake mycelium. The research used an experimental with descriptive analysis method consisting of 11 treatments of rice wastewater concentration i.e. 50%, 55%, 60%, 65%, 70%, 80%, 85%, 90%, 95%, 100%, and PDA as the control, all treatments were replicated three times. The results showed that various concentrations of rice wastewater affected on the growth rate of Shiitake mycelium. The concentration of 100% rice wastewater produced the best growth and quality of mycelium compared to other treatments. Therefore, the rice wastewater can be used as an alternative medium to multiply pure broodstocks of Shiitake mushrooms.

Kokanee–sockeye salmon hybridization leads to intermediate morphology and resident life history: implications for fisheries management

Stocking programs designed to return extirpated species to their historical range have become increasingly prevalent, punctuating the need to better understand the risks posed to recipient ecosystems. Here, we investigated the genetic and biological consequences of an anadromous sockeye salmon (Oncorhynchus nerka) stocking program in Skaha Lake, British Columbia, where substantial levels of hybridization and introgression with the native freshwater resident ecotype (kokanee) have been detected. We genetically assigned 543 individuals (adult spawners, age-0 juveniles) to estimate stock proportions (pure-stock sockeye, pure-stock kokanee, or hybrid) between 2010 and 2017, with a subset undergoing otolith microchemistry analysis to determine migratory life history and maternal ancestry. The proportion of hybrid spawners varied from 5% to 20% across sampling years, while that of hybrid age-0 juveniles remained relatively constant (∼11%). Hybrid spawners exhibited intermediate size relative to pure stocks, with the vast majority being nonanadromous (92%) and of resident maternal ancestry (76%). Our results provide empirical support for previously hypothesized mechanisms of hybridization between O. nerka life-history forms and underscore the importance of continued monitoring of stocking programs to quantify long-term fitness impacts of introgression and refine management strategies.

The control expenditure and quality urban water by NMR flowmeter: relaxometer.

The diminution of pure fresh water stocks and increase the payment for her is demandiny from people rational use her. For this necessaring of urban water expenditure control accurate devices. The many people wants to control the quality urban water of besides the expenditure. This's important for residents at big city. In this city often the different damages occurred in the water - main which result the different chemical elements hit in the clearing water. In the world make many type devices for measuring the expenditure, the concentration different substances in the urban water. This devices use independently. The NMR flowrneter - relaxometer allowed to make the control expenditure and quality urban water of uncontact method by one device.

Distinguishing Colony Opacity Variants and Measuring Opacity Variation in Acinetobacter baumannii.

Many strains of Acinetobacter baumannii, including the highly virulent strain AB5075, undergo a high-frequency switch that results in two cell types that are distinguished by their opaque or translucent colony opacities when viewed by oblique lighting. Opaque (VIR-O) and translucent (AV-T) colonies exhibit multiple phenotypic differences, including virulence. Here we describe how to distinguish between VIR-O and AV-T colony variants and how to generate highly pure stocks of each variant. We also describe methods for measuring opacity switching frequencies of cells grown on agar plates and in liquid cultures.

Identification of barley powdery mildew resistances in gene bank accessions and the use of gene diversity for verifying seed purity and authenticity.

Human activities including those in crop gene banks are subject to errors, especially during seed multiplication and maintenance of seed germination. Therefore, the most serious problem of gene banks is authenticity of the accessions and their genotypic purity. There are many methods for determining the identity of varieties, but comparisons between current data and past records are not easy since the latter are often missing. Breeding barley resistant to powdery mildew caused by Blumeria graminis f. sp. hordei (Bgh) was traditionally based on incorporating major genes into new varieties and the results have been published. Our goal was to identify resistance genes to powdery mildew in accessions of the Czech spring barley core collection and compare these data with earlier information to establish the authenticity of the accessions. Two hundred and twenty-three accessions of the collection including 665 single plant progenies were tested. Sixty-four selected reference isolates of Bgh representing the world diversity of the pathogen were used for resistance tests. Twenty-two known resistance genes were postulated either separately or in combinations. In the collection, 151 homogeneous accessions were found, but the resistances of nine of them were inconsistent with published data and in 12 accessions their authenticity is doubtful. The remaining 72 accessions were heterogeneous and comprised 176 resistance genotypes, 54 of which were probably mechanical admixtures of other varieties. There are several pathogens of cereals, e.g. rusts and mildews, against which many resistance genes in host crops have also been exploited. Knowledge of these resistances can assist in maintaining pure and genuine stocks in gene banks. Seed purity and the authenticity of accessions can subsequently be checked with more advanced methods.

Short-term deleterious effects of standard isolation and cultivation methods on new tropical freshwater microalgae strains.

Algae with potential biotechnological applications in different industries are commonly isolated from the environment in order to obtain pure (axenic) stocks that can be safely stored for long periods of time. To obtain axenic cultures, antibiotics are frequently employed, and cryopreservation is applied to preserve standing stocks. However, many of these now standard methods were developed using strains derived from pristine to near-pristine environments and cold to temperate regions. The potential effect of the said methods on the life cycle and biochemical profile of algae isolates from hyper-eutrophic and constant high-temperature tropical regions is not well understood. These effects could potentially render them unsuitable for their intended biotechnological application. In this study, we conducted a genetic characterization (18S rRNA) and evaluated the effect of purification (the use of the antibiotic chloramphenicol, CAP) and cryopreservation (dimethyl sulfoxide; DMSO–sucrose mix and glycerol) on the growth rate and lipid content of three new tropical freshwater algal isolates: Chorella sp. M2, Chlorella sp. M6, and Scenedesmus sp. R3, obtained from the Ecuadorian coast. The genetic and morphological characterization revealed a clear discrimination between these strains. All strains cultured with CAP exhibited a lower growth rate. Subsequent to cryopreservation, Chorella sp. M2, Chlorella sp. M6, and Scenedesmus sp. R3 presented no significant difference in growth rate between the cryopreservants. Further, a significantly higher lipid content was observed in the biomass cryopreserved with glycerol in relation to the DMSO–sucrose, with Chorella sp. M2 and Chlorella sp. M6 having twice as much as they had in the first treatment. These results highlight the relevance of selecting an appropriate method for storage, as the materials used can affect the biological performance of different tropical species, although it is still to be determined if the effects observed in this study are long lasting in subsequent cultures of these algae.

Genetic variability of pure Pseudoplatystoma corruscans and Pseudoplatystoma reticulatum individuals in the Paraná and Paraguay River basins

The presence of interspecific hybrid surubim (Pseudoplatystoma corruscans × Pseudoplatystoma reticulatum) in natural environments can put at risk the existence of the pure parental lineages. The aim of this study was to characterize the genetic variability of pure Pseudoplatystoma corruscans and Pseudoplatystoma reticulatum individuals from rivers in the Parana and Paraguay basins in Brazil. Seventy-six pure individuals of P. corruscans and 16 of P. reticulatum were evaluated with six microsatellite loci for both species, along with one species-specific locus each for P. corruscans and P. reticulatum. Loss of heterozygosity was confirmed, and preservation measures for P. corruscans and P. reticulatum are needed in order not to lose further genetic variation. In addition, we confirmed that these markers are useful for the management of pure stocks in natural environments, for fish breeding, and in genetic conservation and improvement programs for these species.

Survival and growth of reciprocal crosses between two stocks of the Hong Kong oyster C rassostrea hongkongensis ( L am & M orton, 2003) in southern China

The Hong Kong oyster, Crassostrea hongkongensis, is one of the most economically important and well-known oyster species in southern China. To explore the possibility of improving the performance of the Hong Kong oyster, complete diallel crosses between two oyster stocks, the Zhuhai stock (Z: fast growth line F4) and the Maowei Sea stock (M: resistant line F3), were conducted using pooled gametes. Three replicates, each consisting of two pure stocks (ZZ and MM) and two reciprocal crosses (ZM and MZ), were successfully generated. High fertilization rate and hatching level were observed among all the experimental groups, suggesting that there was no sperm–egg recognition barrier between geographic populations. Reciprocal crosses had higher survival rate compared to the pure stock crosses and the rate of survival increased with progeny growth. Growth heterosis became obvious both in larval and adult stages, and was primarily influenced by the egg origin and mating strategy at the larval stage. Also, the phenotypic traits of all progeny differed amongst the culture sites, suggesting a significant environmental effect. The Zhuhai site was more suitable for oyster aquaculture than the Maowei Sea site. Thus, our results demonstrated that crossbreeding between Zhuhai and Maowei Sea stocks of Hong Kong oyster to produce superior heterosis represents a promising means to improve the fishery yield of this species in southern China.

Institutional investments in pure play stocks and implications for hedging decisions

We show that institutions invest in stocks within an industry that maintain exposure to their underlying industry risk factor. These “pure play” stocks have greater numbers of institutional investors and institutions systematically overweight them in their portfolios while underweighting low industry-exposure stocks of firms in the same nominal industry. Pure play stocks also have greater liquidity measured by stock turnover and price impact. An implication of these results is that catering to these preferences could be an important variable in firms' risk management decisions, potentially offsetting incentives to reduce volatility via hedging. We further characterize institutions' investments for pure play stocks across institution type, industries, and over time.

Mutant USA strain of porcine circovirus type 2 (mPCV2) exhibits similar virulence to the classical PCV2a and PCV2b strains in caesarean-derived, colostrum-deprived pigs.

In 2012, a mutant porcine circovirus type 2 (mPCV2) strain was identified in cases of PCV-associated disease (PCVAD) in the USA. The mPCV2 had an additional amino acid, lysine (K), in the capsid at position 234. The objectives of this study were to compare the pathogenicity of mPCV2, PCV2a and PCV2b in pigs using biologically pure infectious virus stocks derived from respective infectious DNA clones, and to investigate the importance of genotype-specific ORF2 and the presence of lysine at position 234 of the capsid. A total of 47, 2-week-old, caesarean-derived, colostrum-deprived (CDCD) pigs were assigned to one of seven groups. At 3 weeks of age, the pigs were experimentally inoculated with saline, PCV2a, PCV2b, mPCV2, PCV2b-234-K (lysine addition in ORF2), chimeric PCV2b-ORF1/mPCV2-ORF2 or reciprocal chimeric mPCV2-ORF1/PCV2b-ORF2. All pigs were necropsied 21 days post-infection (p.i.). Gross lesions were limited to visible icterus and loss of body condition in a portion of the mPCV2 pigs. The amount of PCV2 DNA was significantly higher in pigs inoculated with mPCV2 compared with PCV2b in sera at 7 days p.i. and faecal swabs at 14 days p.i. Based on lymphoid lesions, a higher prevalence of PCVAD was seen in pigs infected with PCV2s containing the additional 234-K (64.3 %) compared with those infected with a PCV2 with the regular 233 bp ORF2 (40 %). Results indicated that all PCV2 isolates were capable of inducing severe lesions and disease in the CDCD pig model, and there was no significant difference in virulence.