دانلود گزارش کارورزی و کار آموزی

چکیده : 

This study was conducted to investigate the dynamic changes of bulk soil and microbial populations inthe surrounding plant rhizosphere under the influence of chloride de-icing salt. Each experimental plantwas given 0.25 L de-icing salt solution with an irrigation concentration of 200 g/L, once every 3 days for27 days. Samples were taken weekly from each soil layers (0–15 cm, 15–30 cm and 30–45 cm). The resultsrevealed that de-icing salt led to different effects in different soil layers in one month. A trend of increas-ing electric conductivity (EC) values, Na+concentrations, and Cl−concentrations in the upper soil layer,compared with the other two soil layers, was apparent, which proved a stronger effect of de-icing salt onthe upper soil layer. Soil cation exchange capacity (CEC) decreased with the accumulation of the de-icingsalt. Denaturing gradient gel electrophoresis (DGGE) analysis indicated that de-icing salt decreased theShannon diversity (H) and Evenness (E) of fungal populations in three soil layers and led to a decrease ofbacterial H in the upper soil layers. However, a contrary trend for H and E of bacterial populations wasseen in the middle and lower soil layers. Both the unweighted pair group mean average (UPGMA) clus-ter and canonical correspondence analysis (CCA) analysis indicated that the bacterial populations weremore stable than the fungal populations in response to salinity stress. CCA analysis showed the dynamicchanges of microbial populations and the soil properties (EC, CEC, Na+and Cl−) were strongly correla-tive. The microbial populations were obtaining a new dynamic equilibrium at the end of the study. Thedominant microbial populations were originally Crepidotus, Metarhizium, Penicillium and Acidobacterium,but converted to Pythium, Boletaceae, Cystofilobasidiales, Phacidium, Acidobacterium, Pseudomonas andChloroflexi with the addition of de-icing salt. The obtained results suggest that the uses of chemicalagents leading to soil salinization, such as de-icing salt, can destroy the micro-ecosystem of bulk soilsurrounding plant rhizosphere and influence soil health.

چکیده : 

the ultimate goal of soil remediation is to restore soil health. Soil microbial parameters are considered tobe effective indicators of soil health. The aim of this study was to determine the effects of phytoextractionon microbial properties through the measurement of soil microbial biomass carbon, soil basal respira-tion and enzyme activities. For this purpose, a pre-stratified rhizobox experiment was conducted withthe Cd hyperaccumulator Sedum alfredii H. for phytoextraction Cd from an artificial contaminated soil(15.81 mg kg−1) under greenhouse conditions. The plant and soil samples were collected after growingthe plant for three and six months with three replications. The results indicated that the ecotype of S.alfredii H. originating from an ancient silver mining site was a Cd-hyperaccumulator as it showed hightolerance to Cd stress, the shoot Cd concentration were as high as 922.6 mg kg−1and 581.9 mg kg−1at thetwo samplings, and it also showed high BF (58.4 and 36.8 after 3 and 6 months growth), and TF (5.8 and5.1 after 3 and 6 months growth). The amounts of Cd accumulated in the shoots of S. alfredii reached toan average of 1206 g plant−1after 6 months growth. Basal respiration, invertase and acid phosphataseactivities of the rhizosphere soil separated by the shaking method were significantly higher (P < 0.01)than that of the near-rhizosphere soil and the unplanted soil after 3 months growth, so were microbialbiomass carbon, urease, invertase and acid phosphatase activities of the rhizosphere soil after 6 monthsgrowth. Acid phosphatase activity of the 0–2 mm sub-layer rhizosphere soil collected by the pre-stratifiedmethod after 3 months growth was significantly higher (P < 0.05) than that of other sub-layer rhizospheresoils and bulk soil, and so were microbial biomass carbon, basal respiration, urease, invertase and acidphosphatase activities of the 0–2 mm sub-layer rhizosphere soil after 6 months growth. It was concludedthat phytoextraction by S. alfredii could improve soil microbial properties, especially in rhizosphere, andthis plant poses a great potential for the remediation of Cd contaminated soil.

چکیده : 

Previous studies indicate that increasing plant diversity in pastures may prevent mineral

deficiencies or excesses in grazing animals. We tested the hypothesis by comparing

traditional Mongolian nomadic pastoral grazing through which we expected livestock to

consume more plant species, with grazing in a settled area with less plant diversity. We

recorded the number and types of plant species present and the species consumed by a subsample

of grazing sheep. We measured the mineral composition of dominant plant species,

sheep wool and cattle hair. Plant species diversity in vegetation and rumen contents was

greater in the nomadically grazed area than in the settled area. Animals restricted to grazing

in the settled area predominantly consumed a single plant species with poor mineral

balance. In contrast, the concentration of potentially toxic elements of sheep wool was

lower in the nomadically grazed area. These findings suggest that nomadically grazing may

improve the mineral balance of livestock through the intake of diverse plant species.

چکیده : 

A 67year-oldCaucasianmalefromArizonapresentedwithindolentsymptomsofintestinalobstruction

and hydronephrosis,foundatsurgerytobecausedbyamassinvolvingtheterminalileumandcecum,

extendingintotheposteriorabdominalwallandobstructingtherightureter.Histopathologywas

diagnosticofbasidiobolomycosis.PCRoftissueandsequencingidentifiedthefungusas, Basidiobolus

ranarum. Duringoneyearofposaconazoletreatment,theresidualmassshrank,hydronephrosiswas

relievedandperipheraleosinophiliaresolved

چکیده : 

Physico-chemical and sensory characteristics of lambmeatwere evaluated in crossbred ram lambs fromMerino

ewes and Oxford Down, Texel, Charollais, Suffolk and Merinolandschaf sires. The lambs were slaughtered at average

age 119.2 days, live weight 34.6 kg and carcass weight 16.3 kg. Samples of M. longissimus lumborum et

thoracis were used for measurements of pH values, electrical conductivity (EC), drip loss, contents of dry matter

(DM), protein, intramuscular fat (IMF), ash, and hydroxyproline and for sensory analysis. The breed of sire significantly

affected pH 24 and 48 h postmortem, EC 24 h postmortem, protein content and juiciness (P b 0.05).

Significant negative correlations between pH48 and DM (−0.255) and pH48 and IMF (−0.258) were found

(P b 0.05). A significant positive correlation between EC48 and drip loss (0.366) was observed (P b 0.05). Progeny

of Charollais sires hadmeat of better quality than the others; the highest content of protein and IMF, the lowest

drip loss and the best juiciness and texture

چکیده : 

Mammalian Toll-like receptor (TLR) 7 and 8 are responsible for recognizing viral single-stranded RNA

(ssRNA) and are activated by anti-viral imidazoquinoline compounds, leading to a series of defensive

mechanisms being launched to protect the host against viruses. In this study, we identified two TLR7

(with one probably a pseudogene) and three TLR8 genes, namely TLR8a2, TLR8b1 and TLR8b2 from Atlantic

salmon (Salmo salar) whole-genome shotgun (WGS) contigs. Bioinformatics analysis showed that salmon

TLR7 and TLR8a2 are closely related to the corresponding trout orthologs, however, salmon TLR8b1 and

TLR8b2 share the highest amino acid sequence similarity to zebrafish TLR8b and formed a subfamily of

the piscine TLR8 molecules in phylogenetic tree analysis. A conserved gene synteny was found with

the salmon TLR7/8a members as seen in other vertebrate loci. Deduced domain organisation of salmon

TLR7 and TLR8 molecules showed similar structural features, with equal numbers of leucine-rich repeats

(LRRs) and insertion motifs. Individual TLR molecules were expressed in a similar pattern between parr

and post-smolts, with a high expression level in immune tissues. Promoter analysis predicted several

transcription factor binding sites in the TLR8a1/2 and TLR8b1 50 flanking regions, namely C/EBP, AP-1,

STAT, NFjB, and IRF family, suggesting cytokine regulation of the genes. Hence, three recombinant cytokines,

type I IFN, IFNc and IL-1b were used to study the regulation of the salmon TLR gene expression

levels in primary head kidney cells and the Salmon Head Kidney-1 (SHK-1) cell line. Salmon TLR7 and

TLR8a1 gene expression was more sensitive to type I IFN and IFNc treatment in primary head kidney cells

and SHK-1 cells respectively, with no significant up-regulation of TLR8a2 and TLR8b2 by any of the treatments.

On the other hand, salmon TLR8a1 and TLR8b1 were most sensitive to IL-1b treatment in SHK-1

cells and primary head kidney cells, respectively. TLR8b2 was undetectable in SHK-1 cells under these

same conditions.

چکیده : 

Studies of professional accountancy firms have indicated a complex process of internal

socialisation which shapes the professional and organisational identities of the chartered

accountants working within them. These processes have acted as a mechanism for

excluding women, hindering their progress and facilitating their exit. Previous evidence

suggests that women leave professional accountancy firms in order to accommodate more

flexibility, experience less pressure, achieve consistency of hours and hence attain a better

work/life balance.

In this paper we seek to examine whether the gendered work practices of professional

accountancy firms influence female choice to seek alternative employment outside the

professional accountancy firm environment. Specifically the paper seeks to answer two

research questions (1) why and when do women leave professional accountancy firms? (2)

is the working environment outside professional accountancy firms less gendered?

Data was collected by means of a postal questionnaire distributed in 2005 to women who

had qualified in the years 1990–1995 (n ¼ 1022). Responses were received from 370

women, of whom 100 were employed with professional accountancy firms and 270

employed within industry. In depth interviews were also conducted with 7 partners in

professional accountancy firms and 6 women who had left the professional accountancy

environment to pursue employment elsewhere.

Whilst there was evidence that professional accountancy firms continue to reflect

gendered working norms practices, rather than compound the dominant view, this study

suggests that the primary reason women leave professional accountancy firms is to seek

more interesting work as opposed to obtaining more flexibility in their working lives. In

addition, the experiences of the women, the working patterns, and rates of progression

were similar irrespective of employment type.

چکیده : 

Toxicology is the science of chemically induced harmful effects to humans, the domestic animals or plants of humans, or the web of nature at large. Toxicology is a subdiscipline of natural science and should ideally not beget nonsense. Toxicology has developed like other life sciences along positivist lines and with an increasing speed. Especially in the last half of this century, toxicology grew in response to the requirements of industrial hygiene and industrial production of synthetic raw materials and pharmaca. Therefore, toxicology started sharing responsibility for the social implications (industrial medicine, public health) of the expansion of chemical industry and the use of its products.

Copyright © 2013 Elsevier Ltd. All rights reserved 

چکیده : 

In this paper the exact stability stiffness matrix of an Euler–Bernoulli column in presence of an arbitrary

number of concentrated cracks is derived. The procedure for the evaluation of the stability stiffness

matrix is based on the exact closed form solution of the buckling modes of the multi-cracked column,

derived by the present authors in a previous paper. The knowledge of the exact stability stiffness matrix

of the multi-cracked beam allows the direct evaluation of the exact global stability stiffness matrix of

damaged frame structures. Furthermore, the exact evaluation of the buckling loads and the corresponding

buckling modes, consistent with the distributed parameter model, are obtained through the application

of the well-known Wittrick–Williams algorithm. The great advantage of the proposed approach is

that the degrees of freedom of the overall frame structure are exactly the same of the equivalent undamaged

structure irrespective of the number of the concentrated damages. A numerical application, aiming

at validating the exact solution of a framed structure, in presence of concentrated cracks, is reported. The

influence of multiple cracks on the critical load and the corresponding buckling mode of the frame under

study is assessed.

چکیده : 

The paper presents novel mathematical programming approaches for interval limit analysis that are

guaranteed to furnish sharp (extreme) bounds to the collapse load of structures subjected to uncertain

but bounded parameters. The formulation is cast as a pair of linear programs with interval coefficients.

We discuss when sharp collapse load bounds occur when the interval parameters are at the extreme limits

of their respective intervals. A mixed 0–1 programming approach is first proposed to compute the

minimum collapse limit, and, more importantly, we then develop a pair of robust and efficient nonlinear

programming schemes that capture maximum collapse loads in one case and minimum collapse loads in

the other.