An investigation into the effects of computer integrated manufacturing systems in the productivity of SMEs in Pakistan

The current dynamic and turbulent manufacturing environment has forced companies that compete globally to change their traditional methods of conducting business [Producer to consumer]. Recent developments in manufacturing and business operations have lead to the adoption of Computer Integrated Manufacturing (CIM) technologies that are based on systems and processes that support global competitiveness, especially for Small and Medium Enterprises (SMEs). Organizations and SMEs in particular need to re-evaluate every aspect of their manufacturing strategy and quickly move towards a CIM based environment where manufacturing technologies, business strategies and processes are integrated together. This paper highlights the development of a CIM adoption model that has resulted from empirical work generated from SMEs in Pakistan. The model consists of the parameters such as Top Management Support, System Integration, Marketing, and over all performance

The role of laterally transferred genes in adaptive evolution

BACKGROUND: Bacterial genomes develop new mechanisms to tide them over the imposing conditions they encounter during the course of their evolution. Acquisition of new genes by lateral gene transfer may be one of the dominant ways of adaptation in bacterial genome evolution. Lateral gene transfer provides the bacterial genome with a new set of genes that help it to explore and adapt to new ecological niches. METHODS: A maximum likelihood analysis was done on the five sequenced corynebacterial genomes to model the rates of gene insertions/deletions at various depths of the phylogeny. RESULTS: The study shows that most of the laterally acquired genes are transient and the inferred rates of gene movement are higher on the external branches of the phylogeny and decrease as the phylogenetic depth increases. The newly acquired genes are under relaxed selection and evolve faster than their older counterparts. Analysis of some of the functionally characterised LGTs in each species has indicated that they may have a possible adaptive role. CONCLUSION: The five Corynebacterial genomes sequenced to date have evolved by acquiring between 8 – 14% of their genomes by LGT and some of these genes may have a role in adaptation

Synthesis, characterization, docking and antimicrobial activity studies of binuclear Co(II) and Ni(II) complexes of bis aroylhydrazone and phenanthroline

ABSTRACT. Schiff base (HL) N1,N3-bis(4-(methylthio)benzylidene)-5-nitrobenzene-1,3-dihydrazide (HL) has been prepared from condensation of 4-(methyl thio)benzaldehyde with 5-nitrobenzene-1,3-dihydrazide. Binucleated mixed ligand complexes of nickel(II) ([Ni2(L)(dmphen)2]Cl2, [Ni2(L)(phen)2]Cl2) and cobalt(II) ([Co2(HL)(dmphen)2]Cl2, [Co2(HL)(phen)2]Cl2) complexes have been synthesized from Schiff base (HL) and 1,10-phenanthroline/2,9-dimethyl-1,10-phenanthroline. The synthesized compounds have been characterized by elemental analysis, 1H-NMR, 13C-NMR, FT-IR, UV-Visible, magnetic moment, SEM, powder X-ray diffraction and molar conductivity measurements. Further, the Schiff base and its metal complexes have been investigated for fluorescence activity and molecular docking studies. In addition, Schiff base and its metal complexes were screened for antimicrobial activity against bacteria: Escherichia coli, Bacillus subtilis and fungi: Sclerotium rolfsii and Macrophomina phaseolina.                     KEY WORDS: Growth inhibitors, Ternary complex, Tuberculosis, Fluorescence activity, Crystal system   Bull. Chem. Soc. Ethiop. 2021, 35(3), 499-511. DOI: https://dx.doi.org/10.4314/bcse.v35i3.

Engineering Silicon Nanocrystals: Theoretical study of the effect of Codoping with Boron and Phosphorus

We show that the optical and electronic properties of nanocrystalline silicon can be efficiently tuned using impurity doping. In particular, we give evidence, by means of ab-initio calculations, that by properly controlling the doping with either one or two atomic species, a significant modification of both the absorption and the emission of light can be achieved. We have considered impurities, either boron or phosphorous (doping) or both (codoping), located at different substitutional sites of silicon nanocrystals with size ranging from 1.1 nm to 1.8 nm in diameter. We have found that the codoped nanocrystals have the lowest impurity formation energies when the two impurities occupy nearest neighbor sites near the surface. In addition, such systems present band-edge states localized on the impurities giving rise to a red-shift of the absorption thresholds with respect to that of undoped nanocrystals. Our detailed theoretical analysis shows that the creation of an electron-hole pair due to light absorption determines a geometry distortion that in turn results in a Stokes shift between adsorption and emission spectra. In order to give a deeper insight in this effect, in one case we have calculated the absorption and emission spectra going beyond the single-particle approach showing the important role played by many-body effects. The entire set of results we have collected in this work give a strong indication that with the doping it is possible to tune the optical properties of silicon nanocrystals.Comment: 14 pages 19 figure

Enterotoxin genes, enterotoxin production, and methicillin resistance in Staphylococcus aureus isolated from milk and dairy products in Central Italy

AbstractA total of 227 Staphylococcus aureus colonies, isolated from 54 samples of raw milk and dairy products of bovine, ovine, caprine and bubaline origin were tested for the presence of genes coding for staphylococcal enterotoxins (SEs/SEls) and for methicillin resistance. Ninety-three colonies, from 31 of the 54 samples (57.4%) and from 18 (69.2%) of the 26 farms of origin tested positive for SEs/SEls genes. Most isolates harboured more than one toxin gene and 15 different toxinotypes were recorded. The most frequent were “sec” gene alone (28.6%), “sea, sed, ser, selj” (20%), “seg, sei” and “seh” (8.6%). The 77 colonies harbouring “classical enterotoxins” genes (sea-sed) were further tested for enterotoxin production, which was assessed for 59.2% of the colonies. Three methicillin-resistant S. aureus (MRSA) isolates were detected in three different ovine milk/dairy product samples (1.3%). All isolates belonged to spa type t127, sequence type 1, clonal complex 1, SCCmec type IVa

Cosmological Reionization Around the First Stars: Monte Carlo Radiative Transfer

We study the evolution of ionization fronts around the first proto-galaxies by using high resolution numerical cosmological (Lambda+CDM model) simulations and Monte Carlo radiative transfer methods. We present the numerical scheme in detail and show the results of test runs from which we conclude that the scheme is both fast and accurate. As an example of interesting cosmological application, we study the reionization produced by a stellar source of total mass M=2 10^8 M_\odot turning on at z=12, located at a node of the cosmic web. The study includes a Spectral Energy Distribution of a zero-metallicity stellar population, and two Initial Mass Functions (Salpeter/Larson). The expansion of the I-front is followed as it breaks out from the galaxy and it is channeled by the filaments into the voids, assuming, in a 2D representation, a characteristic butterfly shape. The ionization evolution is very well tracked by our scheme, as realized by the correct treatment of the channeling and shadowing effects due to overdensities. We confirm previous claims that both the shape of the IMF and the ionizing power metallicity dependence are important to correctly determine the reionization of the universe.Comment: 8 pages, 8 figures. Revised version, accepted for publication by MNRA

A connection between stress and development in the multicelular prokaryote Streptomyces coelicolor

Morphological changes leading to aerial mycelium formation and sporulation in the mycelial bacterium Streptomyces coelicolor rely on establishing distinct patterns of gene expression in separate regions of the colony. sH was identified previously as one of three paralogous sigma factors associated with stress responses in S. coelicolor. Here, we show that sigH and the upstream gene prsH (encoding a putative antisigma factor of sH) form an operon transcribed from two developmentally regulated promoters, sigHp1 and sigHp2. While sigHp1 activity is confined to the early phase of growth, transcription of sigHp2 is dramatically induced at the time of aerial hyphae formation. Localization of sigHp2 activity using a transcriptional fusion to the green fluorescent protein reporter gene (sigHp2–egfp) showed that sigHp2 transcription is spatially restricted to sporulating aerial hyphae in wild-type S. coelicolor. However, analysis of mutants unable to form aerial hyphae (bld mutants) showed that sigHp2 transcription and sH protein levels are dramatically upregulated in a bldD mutant, and that the sigHp2–egfp fusion was expressed ectopically in the substrate mycelium in the bldD background. Finally, a protein possessing sigHp2 promoter-binding activity was purified to homogeneity from crude mycelial extracts of S. coelicolor and shown to be BldD. The BldD binding site in the sigHp2 promoter was defined by DNase I footprinting. These data show that expression of sH is subject to temporal and spatial regulation during colony development, that this tissue-specific regulation is mediated directly by the developmental transcription factor BldD and suggest that stress and developmental programmes may be intimately connected in Streptomyces morphogenesis

The impact of mergers on relaxed X-ray clusters - III. Effects on compact cool cores

(Abridged) We use the simulations presented in Poole et al. 2006 to examine the effects of mergers on compact cool cores in X-ray clusters. We propose a scheme for classifying the morphology of clusters based on their surface brightness and entropy profiles. Three dominant morphologies emerge: two hosting compact cores and central temperatures which are cool (CCC systems) or warm (CWC systems) and one hosting extended cores which are warm (EWC systems). We find that CCC states are disrupted only after direct collisions between cluster cores in head-on collisions or during second pericentric passage in off-axis mergers. By the time they relax, our remnant cores have generally been heated to warm core (CWC or EWC) states but subsequently recover CCC states. The only case resulting in a long-lived EWC state is a slightly off-axis 3:1 merger for which the majority of shock heating occurs during the accretion of a low-entropy stream formed from the disruption of the secondary's core. Compression prevents core temperatures from falling until after relaxation thus explaining the observed population of relaxed CWC systems with no need to invoke AGN feedback. The morphological segregation observed in the L_x-T_x and beta-r_c scaling relations is reflected in our simulations as well. However, none of the cases we have studied produce sufficiently high remnant central entropies to account for the most under-luminous EWC systems observed. Lastly, systems which initially host central metallicity gradients do not yield merger remnants with flat metallicity profiles. Taken together, these results suggest that once formed, compact core systems are remarkably stable against disruption from mergers. It remains to be demonstrated exactly how the sizable observed population of extended core systems was formed.Comment: 19 pages, 8 figures, submitted for publication in MNRA

MENINGITE VIRALE DA HHV7. DESCRIZIONE DI UN CASO IN ADULTO IMMUNOCOMPETENTE

INTRODUZIONE: Human Herpesvirus 7 (HHV7) è un virus erpetico ubiquitario, la cui patogenicità non è ancora del tutto nota. Nella maggior parte dei casi l’infezione è asintomatica, sebbene siano descritti casi di febbre, exanthema subitum o convulsioni febbrili in età pediatrica. Nel paziente adulto, immunodepresso e non, sono riportati casi aneddotici di coinvolgimento del SNC (encefalite e mielite). OBIETTIVI: Descriviamo un caso clinico di meningite a liquor limpido con isolamento liquorale di HHV-7, in giovane adulto immunocompetente.CASO CLINICO: Maschio di 18 anni originario della Guinea, in Italia da 3 anni senza precedenti anamnestici. Giungeva alla nostra osservazione per febbre e cefalea con quadro clinico obiettivo di irritazione meningea, in assenza di deficit neurologici focali o alterazione del sensorio. Gli esami ematochimici mostravano PCR 1,09 mg/dl, emocromo con formula e funzionalità epatorenale nei limiti. Veniva eseguito prelievo di liquido cefalorachidiano che si presentava lievemente torbido; l’esame chimico-fisico evidenziava glicorrachia nella norma, iperprotidorrachia (87 mg/dl) e pleiocitosi (574 cell/mmc di cui 81,7% mononucleati). Su liquor sono risultati negativi: coltura per batteri e miceti, diagnosi molecolare (film array multiplex o PCR) per E. coli, H. influenzae, L. monocytogenes e N. meningitidis, S. pneumoniae, HSV 1-2, Cryptococcus, CMV, EBV, Toscana virus, Picornavirus, West- Nile virus, Usutu virus, HHV6, HHV8, Chikungunya virus, Adenovirus, Parechovirus. Positiva la PCR su liquor per HHV-7. Negativi inoltre test HIV, sierologia per HCV, VDRL e TPHA; il quadro sierologico per HBV era compatibile con vaccinazione pregressa. Nei limiti RX torace, ECG ed ecocardiogramma. Il paziente, sottoposto a terapia sintomatica, presentava rapido sfebbramento con regressione del quadro clinico. CONCLUSIONI. Sebbene l’isolamento di HHV7 su liquor potrebbe rappresentare un evento aspecifico, espressione di riattivazione di infezione latente, la negatività delle altre indagini microbiologiche effettuate e l’assenza di immunodeficit, rendono plausibile una correlazione eziologica del virus con la forma di meningite linfomonocitaria descritta