Search

Staphylococcus aureus is an important cause of contagious intramammary infection in dairy cattle, and the ability to produce biofilm is considered to be an important virulence property in the pathogenesis of mastitis. The aim of this study was to characterize the biofilm formation capacity of methicillin-resistant Staph. aureus (MRSA), encoding mecA or mecC, isolated from bulk tank milk in Great Britain. For this purpose, 20 MRSA isolates were grown on microtiter plates to determine the biofilm production. Moreover, the spa-typing and the presence of the intercellular adhesion genes icaA and icaD were analyzed by PCR. All MRSA isolates tested belonged to 9 spa-types and were PCR-positive for the ica genes; 10 of them (50%) produced biofilm in the microtiter plate assay. This is also the first demonstration of biofilm production by mecC MRSA.

Methicillin-resistant Staphylococcus aureus (MRSA) is a public health concern due to limited treatment options. The recent description of a mecA homologue, mecC in human and cattle, led to studies to detect this new variant in human and other animal species. Detection of mecC in wild boar and fallow deer in a Spanish game estate led us to further investigate the presence of mecC-MRSA at this location. Samples from cattle, wild animals, workers and river water were tested. A further three mecC-MRSA isolates were obtained from river water. Molecular characterization (multilocus sequence typing and spa typing) and antimicrobial susceptibility testing (broth microdilution) showed that isolates were similar to those detected in wild animals. Whole genome sequencing confirmed that the isolates from the river water and wild animals in the same geographic area were all closely related isolates of ST425 mecC-MRSA. The presence of mecC-MRSA in the river water highlights the potential role of water in the dissemination of mecC-MRSA.

Purpose: This study compared blood pressure, heart rate variability (HRV) and forearm blood flow, at rest and in response to sympathoexcitatory stressors between normotensive and mildly hypertensive participants. Methods: Participants aged 30–79 years with normal blood pressure (n = 49) or mild hypertension (n = 17), with no history of taking antihypertensive medication, were recruited. Participants completed a cold pressor test (CPT) followed by an ischaemic handgrip test (IHGT). Blood pressure, HRV, forearm blood flow and vascular resistance were measured at rest and in response to each test. Results: The CPT and IHGT evoked greater increases in mean arterial blood pressure in hypertensive participants (CPT: 10 ± 2 mmHg, IHGT: 9 ± 1 mmHg) compared with normotensive participants (CPT: 5 ± 1 mmHg, IHGT: 3 ± 1 mmHg; P

Total serum bilirubin (TBIL) is used as a prognostic factor in chronic hepatitis (CH) in human beings. To date, the authors are unaware of any studies looking at the value of TBIL as a prognostic factor in idiopathic canine CH. The objective of the current study was to assess if TBIL is a negative prognostic factor in idiopathic canine CH, and to identify other prognostic factors. Thirty-nine dogs with histologically confirmed idiopathic CH admitted to 2 referral centers between 1999 and 2010 were included in the study. Patients with concurrent diseases that could affect TBIL or the survival time were excluded. Total serum bilirubin was measured prior to liver biopsy, and CH was diagnosed according to standardized histological criteria. Survival time was calculated from time of diagnosis to time of death or euthanasia. Cox proportional hazard analysis was performed to identify prognostic factors. The mean survival time for the 39 dogs included in the analysis was 197 days (1–2,677), and the mean total serum bilirubin was 11 μmol/l (2–265). Total serum bilirubin was statistically significantly associated with survival (odds ratio = 1.082, P = 0.047) as were weight (odds ratio = 1.028, P = 0.028) and the presence of ascites (odds ratio = 6.758, P = 0.013). The current study demonstrates that TBIL could be used as an additional prognostic factor in canine CH.

This study provides new evidence of nonlinearities in the dynamics of volatility expectations during financial crises using Markov regime-switching models of model-free volatility indices. The regimes of changes in implied volatility in international financial markets are defined as function of market sentiment and a realignment process following forecast errors consistent with rational expectations. The results indicate that market returns and changes in forecast errors have indeed the potential of influencing the formation of volatility expectations. But the main force driving the dynamics of volatility expectations during periods of financial instability lies rather in the correlation with returns, reflecting market sentiment. The insignificance of the realignment process may be reflective of consensus beliefs that past information does not provide useful guidance during financial crises. It is forward-looking macroeconomic information and contemporaneous price movements that are more likely to shape t...

Background Equine influenza virus (EIV) is considered enzootic in Europe (except Iceland), Asia, North Africa, and North and South America. When EIV outbreaks occur they may severely impact the equine and tourist industries. Australia faced its first EIV outbreak beginning in August of 2007. The outbreak was concentrated in New South Wales and Queensland, with more than 1400 confirmed EIV infections in horses during the first month. Rapid response from the equine industry and the federal government was successful and Australia was declared free from EIV by the end of 2007. Objectives This cross-sectional study was designed to examine associations between exposure to EIV-infected horses and evidence of EIV infection in humans. Study design Employing informed consent, between October 2007 and April 2008, 100 subjects (89 with horse exposures and 11 non-exposed) were enrolled during equine events and at the University of the Sunshine Coast. All subjects provided a blood sample and were asked to complete an online questionnaire including health history, animal exposure and demographic information. Sera samples were tested for the presence of antibodies against two H3N8 EIV strains using microneutralization, hemagglutination inhibition, and enzyme-linked lectin assays. Results Evidence for H3N8 infection was sparse, with only 9 study participants having any indication of H3N8 infection and the seroreactivity seen was low and easily explained by cross-reactions against human influenza strains or vaccines. Conclusions These data provide little evidence to support the premise that EIV infections occurred among humans exposed to EIV-infected horses during the 2007 Australian epizootic.

Studies of the linkage between exports and profitability often use mean regression approaches and focus only on European countries. Using a panel data quantile regression approach, this study analyses the linkage between export behaviour and profit growth in Vietnam. Using a panel dataset from 2005 to 2009, our results show an insignificant linkage between export status and firm profit growth when using OLS. However, when using a quantile approach, export participation is found to be positively related to profitability for those firms with high profit growth but negatively related for those firms with low profit growth. This might suggest that the productivity advantages of exporters with low profit growth are absorbed by costs relating to trading activities in overseas markets.

Objective To evaluate the quasi-isometric points (nearest isometric points) between the distal aspect of the femur and fabella and the proximal aspect of the tibia for placement of a lateral suture in cats. Study Design Radiographic study. Animals Cadaveric cat stifles (n = 7 cats; 14 stifles). Methods Specimens were secured in a mounting frame to maintain rigid fixation of the femur and allow free range of motion of the stifle joint and proximal tibia. Two anatomic landmarks were identified: the center of the lateral fabella (Ff) and a point 4 mm proximal to the insertion of the patellar tendon adjacent to the tibial cortex (Tt). Radiopaque spheres were placed at predefined landmarks in the femur (caudal aspect of the lateral femoral condyle distal [F1] and proximal [F2] to the lateral fabella) and in the tibia (caudal to the proximal aspect of the extensor groove [T1]; cranial to the proximal aspect of the extensor groove [T2]; 2 mm proximal and caudal to the insertion of the patellar tibial tendon [T3] and 3 mm caudal to the insertion of the patellar tibial tendon [T4]. For each stifle, 4 radiographic projections were made: in extension (166°), in flexion (45°), and 2 intermediate stance phases (90°, 130°). ANOVA was used to compare means of the distance between the point pairs and means of the percent change in variation of distance (VOD%) using the 45° measurement as a reference. Results Mean VOD% nearest to zero, over all the different angles tested, was produced by Ff-Tt, which was statistically significantly different from each of the other point pairs. Conclusion Ff-Tt provides the best quasi-isometric points for placement of lateral sutures in cats, compared with all combinations tested. Further assessments with biomechanical studies are needed to evaluate the reproducibility of these landmarks for stabilization of CCL rupture in cats.

This paper uses a novel dataset of poor households in peri-urban areas in Vietnam to estimate impacts of small loans on child schooling. The Probit and Negative Binomial model estimates roughly indicate no strong evidence of the effect. However, breaking down credit into formal and informal credit and credit for boy and girl schooling provides better insights. The paper suggests that to obtain the target of sustainable poverty reduction, easing access to formal credit sources and exempting tuition and other school contributions are necessary steps to keep poor children in schools longer.

The aim of this study was to examine the gene transfer potential of mef(A)-containing Tn120.3 to macrolide-susceptible Streptococcus pyogenes belonging to different emm types. Using the filter mating technique, Tn1207.3 was transferred by conjugation to 23 macrolide-susceptible recipients representing 11 emm types. PCR analysis confirmed the presence of the mef(A) gene and the comEC junction regions of the Tn1207.3 insertion in resultant transconjugants. Significant variation was found in the transfer frequency of Tn1207.3 to different Strep. pyogenes strains, and this phenomenon may contribute to the differences in mef(A) frequency observed among clinical isolates. Significance and Impact of the Study The spread of antimicrobial resistance among pathogenic bacteria is an important problem, but the mechanisms of horizontal transfer between strains and species are often poorly understood. For instance, little is known on how macrolide resistance spreads between strains of the human pathogen Strep. pyogenes and why certain strains more commonly display resistance than others. Here, we show that Strep. pyogenes strains vary greatly in their ability to acquire a transposon encoding macrolide resistance by horizontal gene transfer in vitro. These data provide a novel insight into the transfer of antibiotic resistance between bacterial strains and offer an explanation for the differences in the frequency of resistance determinates and resistance seen among clinical isolates. Significance and Impact of the Study: The spread of antimicrobial resistance among pathogenic bacteria is an important problem, but the mechanisms of horizontal transfer between strains and species are often poorly understood. For instance, little is known on how macrolide resistance spreads between strains of the human pathogen Strep. pyogenes and why certain strains more commonly display resistance than others. Here, we show that Strep. pyogenes strains vary greatly in their ability to acquire a transposon encoding macrolide resistance by horizontal gene transfer in vitro. These data provide a novel insight into the transfer of antibiotic resistance between bacterial strains and offer an explanation for the differences in the frequency of resistance determinates and resistance seen among clinical isolates.

This study examines how state subsidies to firms affect corporate investment efficiency. Using archival data from a sample of Chinese listed firms over the 2007–2015 period, we find that government subsidies have a negative effect on firms' investment efficiency, and this negative effect is more pronounced for firms that are less financially constrained. Further analyses suggest that government subsidies are positively associated with firms' over-investment, although they alleviate under-investment. Our findings are robust to a series of tests to alleviate concerns about potential endogeneity and self-selection bias.

We report the realization of single photon emission from an InGaN quantum dot in a GaN inverted truncated-pyramid structure: a single photon horn. The structural parameters of the quantum dots, especially the quantum confinement in the (0001) direction, are well controlled by optimizing the planar single InGaN quantum well to be of ∼2 monolayers. Based on conventional nanoimprint pillars combining with a simple regrowth process, the single photon horn structure is realized with an efficient photon emission of 8 × 105 photons/s while still maintaining a g(2)(0) < 0.5 even at an extremely low excitation power of 35 nW (4.5 W cm−2).

We report the observation and characterization of sharp emission lines from Zn-related emission centers in GaN. Initial studies on the emission lines show that they appear only at low temperatures (T?50?K), are energetically stable, and exhibit linewidths of a few meV. A brief discussion on their possible origins is given.

We examine the long-run relationship between remittances and the real exchange rate for less-developed countries. In a key departure from the literature, we employ a panel cointegration approach using an innovative method for the measurement of the multilateral real effective exchange rate and we focus on high-remittance economies. We find a small inelastic, but significant, long-run relationship which confirms a Dutch disease type effect. The short-run relationship is explored using a panel vector error correction model which confirms that short-run causality is unidirectional running from remittances to the exchange rate. Potential asymmetries in this relationship are identified using quantile regression analysis.

Objectives: There are limited data available on the epidemiology and prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in the human population that encode the recently described mecA homologue, mecC. To address this knowledge gap we undertook a prospective prevalence study in England to determine the prevalence of mecC among MRSA isolates. Patients and methods: Three hundred and thirty-five sequential MRSA isolates from individual patients were collected from each of six clinical microbiology laboratories in England during 2011–12. These were tested by PCR or genome sequencing to differentiate those encoding mecA and mecC. mecC-positive isolates were further characterized by multilocus sequence typing, spa typing, antimicrobial susceptibility profile and detection of PBP2a using commercially available kits. Results: Nine out of the 2010 MRSA isolates tested were mecC positive, indicating a prevalence among MRSA in England of 0.45% (95% CI 0.24%–0.85%). The remainder were mecA positive. Eight out of these nine mecC MRSA isolates belonged to clonal complex 130, the other being sequence type 425. Resistance to non-β-lactam antibiotics was rare among these mecC MRSA isolates and all were phenotypically identified as MRSA using oxacillin and cefoxitin according to BSAC disc diffusion methodology. However, all nine mecC isolates gave a negative result using three different commercial PBP2a detection assays. Conclusions: mecC MRSA are currently rare among MRSA isolated from humans in England and this study provides an important baseline prevalence rate to monitor future changes, which may be important given the increasing prevalence of mecC MRSA reported in Denmark.

The aim of this study was to provide quantitative data on time commitment needed for care of dogs with chronic severe spinal cord injury (SCI) at home and assess effect on the owner's home lives. It was not a study aimed at assessing the quality of life (QOL) of the dogs as this has previously been examined, although a small amount of data was collected on this aspect. A questionnaire was sent to 40 owners of dogs with clinically complete chronic SCI (defined by lack of observable response to a noxious stimulus applied to the hind limbs, the absence of voluntary hind limb locomotor function, and urinary and fecal incontinence for more than 9 months at the time the study was conducted). Owners were asked to quantify the time spent exercising their pet, managing urinary and fecal incontinence and giving general skin and fur care. Other questions sought to determine the effect on family relationships. The study population included 27 dachshunds and 10 other breeds. Twenty-six questionnaires were returned for analysis, giving a response rate of 65%. Owners spent between 2 and 44 hours in total per week managing their dog (median, 14 hours), with between 1 and 30 hours spent on mobility management (median, 10 hours) and between 0 and 16 hours (median, 3 hours) on incontinence. About 92% of owners were living with a partner, and at least one in the couple did not work full time, 84% had no children younger than 16 years, 64% either currently or previously owned another dog, and 73% declared that they had not considered euthanasia as an option at the time of the SCI. Twenty owners strongly agreed that the work involved was worthwhile, and 16 owners felt that the work involved had strengthened the bond between them and their pet. One owner felt that the care required had reduced their own QOL and 2 owners reported serious family problems. The dogs studied form a particular subset of cases because they had been cared for by their owners for at least 9 months. However, this study provides information that will aid informed decision making by owners and veterinarians at the time of a dog SCI, providing an indication of what can be expected in the chronic phase of SCI.

The objective of this study was to determine whether unimodal auditory stimuli evoke event-related potentials (ERPs) in brain areas normally designated as the visual cortex (VC). The topographical distribution of ERPs evoked by auditory click stimuli was measured from (a) electroencephalographic electrodes on the scalp of six neurologically normal adult human participants and (b) intracranial electrodes implanted on the cortex of one epileptic adult human participant. In all participants, unimodal click stimuli evoked ERPs over both the auditory cortex (AC) and the VC. Relative amplitudes of ERPs at different scalp electrodes did not support the idea that the ERPs over VC were volume-conducted versions of those over AC, and intracranial records confirmed the origin of some click-evoked ERPs in both V1 and other regions of VC. We conclude that unimodal auditory stimuli can evoke ERPs in VC. This finding adds to the earlier evidence for the effect of visual stimuli on AC by providing new evidence for bidirectional functional connectivity in the audio-visual network of the human brain. The implication is that not only do visual stimuli affect hearing; auditory stimuli also affect visual perception.

Objectives mecC methicillin-resistant Staphylococcus aureus (MRSA) represent a newly recognized form of MRSA, distinguished by the possession of a divergent mecA homologue, mecC. The first isolate to be identified came from bovine milk, but there are few data on the prevalence of mecC MRSA among dairy cattle. The aim of this study was to conduct a prevalence study of mecC MRSA among dairy farms in Great Britain. Methods Test farms were randomly selected by random order generation and bulk tank samples were tested for the presence of mecC MRSA by broth enrichment and plating onto chromogenic agar. All MRSA isolated were screened by PCR for mecA and mecC, and mecC MRSA were further characterized by multilocus sequence typing, spa typing and antimicrobial susceptibility testing. Results mecC MRSA were detected on 10 of 465 dairy farms sampled in England and Wales (prevalence 2.15%, 95% CI 1.17%–3.91%), but not from 625 farms sampled in Scotland (95% CI of prevalence 0%–0.61%). Seven isolates belonged to sequence type (ST) 425, while the other three belonged to clonal complex 130. Resistance to non-β-lactam antibiotics was uncommon. All 10 isolates produced a negative result by slide agglutination for penicillin-binding protein 2a. mecA MRSA ST398 was detected on one farm in England. Conclusions mecC MRSA is widely distributed among dairy farms in Great Britain, but this distribution is not uniform across the whole country. These results provide an important baseline dataset to monitor the epidemiology of this emerging form of MRSA.

This article tests for stock market efficiency among 12 Asia-Pacific countries. A novel approach is applied where unit-root tests of real stock prices are embedded within a Markov regime-switching framework. Although standard univariate unit-root tests provide little support for stock price mean reversion, we find that each country is characterized by two stationary regimes with different speeds of adjustment. Further analysis suggests that the recent global financial crisis is associated with a shift in regimes, where the aftermath of the crisis is more likely associated with a faster speed of mean-reversion.

The increasing popularity of local food consumption can be attributed to the heightened awareness of food safety concerns, carbon emissions produced from food transportation, and an understanding of how large corporations’ obtain their food supplies. Although there is increasing discussion on both the local and organic food movement independently, there is not a wide availability of literature examining the motivations and perceptions of consumers with regard to farmers’ markets. Issues such as perceptions about what type of food consumers are purchasing at markets, nor the main motivations for frequenting such establishments are discussed. Therefore the purpose of this study was to determine consumer motivations, benefits, and perceptions of farmers’ markets. Using the case study location of Toronto, Canada, this study surveyed 300 participants during the fall of 2011. Findings indicated that the main purpose for visiting famers’ markets is not solely to fulfill grocery needs. Quality of products offered and the ability to support the local community were the primary motivators to visit the markets.

We explore the connection between the average propensity to consume ( APC ) and wealth to income ratio ( WY ) in the US. We find evidence of a long-run relationship characterised by threshold error correction. It is the APC that responds to long-run disequilibrium where the speed of adjustment is asymmetric insofar as being most likely fastest in regimes characterised by a high APC and low WY .

The main purpose of this study is to identify the best practices of monetary policy implementation in the Eritrean economy. As such, the paper examines what kind of monetary policy and transmission mechanisms are relevant to the Eritrean economy. It also addresses which channels are effective and which are not and why. Vector Autoregressive modelling is employed over the study period 1996Q1–2008Q4. This paper addresses the argument that the bank lending is the sole functioning channel in low income economies. We find that interest rate and official exchange rate channels are inoperative. However, effective exchange rate and credit channels exist through the black foreign exchange market and credit issued to the government sector. The main policy implication of this study is that the Bank of Eritrea might be able to control inflation through manipulating the reserve requirement ratio.

In this paper, we study the hitherto unexplored evolution of the size distribution of 185 functionally defined urban areas in Brazil between 1907 and 2008. We apply the traditional power law and the Gabaix-Ibragimov improved estimation method. We find that the power parameter of the size distribution of the 100 largest urban areas increases towards unity, that is, the rank-size rule. Seventeen thousand and twenty cointegration tests of pairwise non-stationary growth paths of cities point to evidence of a common stochastic trend that strengthens throughout the century. Thus, while Zipf's law and Gibrat's law did not formally hold in Brazil's past, these laws are becoming steadily more appropriate descriptions of Brazil's increasingly unequal size distribution of cities.

Long-run income convergence is investigated in the U.S. context. We employ a novel pairwise econometric procedure based on a probabilistic definition of convergence. The time-series properties of all the possible regional income pairs are examined by means of unit root and non-cointegration tests, where inference is based on the fraction of rejections. We distinguish between the cases of strong convergence, where the implied cointegrating vector is [1, -1], and weak convergence, where long-run homogeneity is relaxed. To address cross-sectional dependence, we employ a bootstrap methodology to derive the empirical distribution of the fraction of rejections. We find supporting evidence of U.S. states sharing a common stochastic trend consistent with a definition of convergence based on long-run forecasts of state incomes being proportional rather than equal. We find that the strength of convergence between states decreases with distance and initial income disparity. Using Metropolitan Statistical Area data, evidence for convergence is stronger. © 2013 Cambridge University Press.

Relying on hard currency or dollarizing an economy has been a common practice of many developing countries taking the form of dollarizing bank deposits and loans, settling transactions in dollars and the indexation of wages and prices in dollars. The relationship between dollarization and exchange rate volatility is both theoretically and empirically unresolved. While the effect of such practices has been the focus of numerous investigations, such studies have concentrated on the Latin American and Asian economies. This paper contributes to the limited research on the African economies by specifically investigating the consequences of dollarization on Eritrean exchange rate volatility. Using quarterly official and black market exchange rate data for the study period 1996-2008, E-GARCH analysis suggests that dollarization has a positive impact on real exchange rate volatility.Keywords: Dollarization, Exchange Rate Volatility, Eritrea, Official and Black MarketJEL classification: F3, O2, O5(ProQuest: ... denotes formulae omitted.)1. INTRODUCTIONThe dollarization of the developing countries has been an inspiring field of research for many scholars. Despite a number of studies that address the measurement and consequences of dollarization, this literature concentrates on the Latin American and Asian economies with very limited focus on African economies. In this paper, we investigate whether dollarization alleviates or aggravates exchange rate volatility in the case of Eritrea. The existing literature suggests that the impact of dollarization can depend on the form of dollarization that exists in a given economy. For example, Akofio-Sowah (2009), Savvides (1996), Schnabl, (2007) and Barrell et al. (2009) among others show that if dollarization is full, then dollarization minimises exchange rate volatility. Similarly, Fielding and Shields (2003) argue that full monetary union leads to lower real exchange rate volatility than is the case under a fixed exchange rate system. However, if dollarization takes a partial form, then the evidence is less clear-cut. The theoretical work of Girton and Roper (1981), Akcay et al. (1997) and Corrado (2008) demonstrate that exchange rate instability increases with the increase of the degree of currency substitution. Empirical studies by Calvo and Vegh (1992, 1996), Yinusa (2008) and Akcay et al. (1997) suggest that an increase in dollarization increases the exchange rate volatility. In contrast to these studies, Devereux and Lane (2003) find that financial dollarization in the form of acquiring dollar loans alleviates exchange rate volatility.In addition to an African focus, our contribution to the literature is further enhanced through the construction and utilisation of a new hard currency index based on a holistic approach towards its measurement. This approach suits the nature of the Eritrean economy and addresses the shortcomings of alternative measures of dollarization adopted by earlier studies. In further contrast to the existing literature, we analyse both the official and black market exchange rate in both nominal and real form.The paper is organized as follows. In the following section, we briefly review the relevant literature. The third section discusses the data and methodology. Quarterly time series data for Eritrea are employed for the study period 1996Q1-2008Q4. Estimation is based on extending the Exponential Generalised Autoregressive Conditionally Heteroscedasticity (E-GARCH) model originally proposed by Nelson (1991). The fourth section offers a discussion of the econometric findings. We find that dollarization has a positive impact on exchange rate volatility. The final section offers a summary and conclusion.2. LITERATURE REVIEWDollarization, which refers to the use of US dollars or any other foreign currency within the domestic economy, has become a contemporary economic feature of many countries from the developing world. …

This paper explores the correlates of career satisfaction among Canadian managers, professionals and executives, specifically the career satisfaction experience of both visible minority and non-visible minority immigrants. Survey data collected from over 13,000 managers, professionals and executives in 43 Canadian organizations were analysed using the ordinary least squares multiple regression technique. Results indicate that immigrants experience lower career satisfaction than native-borns and visible minority immigrants have lower career satisfaction than non-visible minority immigrants. Employee and employer characteristics, objective employment outcomes and subjective perceptual measures were found to be positively associated with career satisfaction for immigrant and native-born respondents.

Semiconducting single-walled carbon nanotubes are one-dimensional materials with great prospects for applications such as optoelectronic and quantum information devices. Yet, their optical performance is hindered by low fluorescent yield. Highly mobile excitons interacting with quenching sites are attributed to be one of the main non-radiative decay mechanisms that shortens the exciton lifetime. In this paper we report on time-integrated photoluminescence measurements on individual polymer wrapped semiconducting carbon nanotubes. An ultra narrow linewidth we observed demonstrates intrinsic exciton dynamics. Furthermore, we identify a state filling effect in individual carbon nanotubes at cryogenic temperatures as previously observed in quantum dots. We propose that each of the CNTs is segmented into a chain of zero-dimensional states confined by a varying local potential along the CNT, determined by local environmental factors such as the amount of polymer wrapping. Spectral diffusion is also observed, which is consistent with the tunneling of excitons between these confined states.

Passerine salmonellosis is a well-recognized disease of birds in the order Passeriformes, which includes common songbirds such as finches and sparrows, caused by infection with Salmonella enterica serovar Typhimurium. Previous research has suggested that some subtypes of S . Typhimurium—definitive phage types (DTs) 40, 56 variant, and 160—are host adapted to passerines and that these birds may represent a reservoir of infection for humans and other animals. Here, we have used the whole-genome sequences of 11 isolates from British passerines, five isolates of similar DTs from humans and a domestic cat, and previously published S . Typhimurium genomes that include similar DTs from other hosts to investigate the phylogenetic relatedness of passerine salmonellae to other S . Typhimurium isolates and investigate possible genetic features of the distinct disease pathogenesis of S . Typhimurium in passerines. Our results demonstrate that the 11 passerine isolates and 13 other isolates, including those from nonpasserine hosts, were genetically closely related, with a median pairwise single nucleotide polymorphism (SNP) difference of 130 SNPs. These 24 isolates did not carry antimicrobial resistance genetic determinants or the S . Typhimurium virulence plasmid. Although our study does not provide evidence of Salmonella transmission from passerines to other hosts, our results are consistent with the hypothesis that wild birds represent a potential reservoir of these Salmonella subtypes, and thus, sensible personal hygiene precautions should be taken when feeding or handling garden birds. IMPORTANCE Passerine salmonellosis, caused by certain definitive phage types (DTs) of Salmonella Typhimurium, has been documented as a cause of wild passerine mortality since the 1950s in many countries, often in the vicinity of garden bird feeding stations. To gain better insight into its epidemiology and host-pathogen interactions, we sequenced the genomes of a collection of 11 isolates from wild passerine salmonellosis in England and Wales. Phylogenetic analysis showed these passerine isolates to be closely related to each other and to form a clade that is distinct from other strains of S . Typhimurium, which included a multidrug-resistant isolate from invasive nontyphoidal Salmonella disease that shares the same phage type as several of the passerine isolates. Closely related to wild passerine isolates and within the same clade were four S . Typhimurium isolates from humans as well as isolates from horses, poultry, cattle, an unspecified wild bird, and a domestic cat and dog with similar DTs and/or multilocus sequence types. This suggests the potential for cross-species transmission, and the genome sequences provide a valuable resource to investigate passerine salmonellosis further.

Highlights • Disease and non-disease associated isolates had different resistance profiles. • Antimicrobial resistance increased over time among clinical isolates. • Prevalence of isolates with resistance to multiple antimicrobials is increasing. • Combination of different approaches enhances the information obtained from the data., Antimicrobial resistance in Streptococcus suis, a global zoonotic pathogen of pigs, has been mostly studied only in diseased animals using surveys that have not evaluated changes over time. We compared patterns of resistance between S. suis isolates from clinical cases of disease (CC) and non-clinical case (NCC) pigs in England, collected over two discrete periods, 2009–2011 and 2013–2014. Minimum inhibitory concentrations (MIC) of 17 antimicrobials (nine classes) were determined on 405 S. suis isolates categorised by sampling period and disease association to assess changes in resistance over time and association with disease. First, isolates were characterized as resistant or susceptible using published clinical breakpoints. Second, epidemiological cut-offs (ECOFF) were derived from MIC values, and isolates classified as wild type (WT) below the ECOFF and non-wild type (NWT) above the ECOFF. Finally, isolate subsets were analysed for shifts in MIC distribution. NCC isolates were more resistant than CC isolates to cephalosporins, penams, pleuromutilins, potentiated sulphonamides and tetracyclines in both study periods. Resistance levels among CC isolates increased in 2013–2014 relative to 2009–2011 for antimicrobials including aminoglycosides, cephalosporins, fluoroquinolones, pleuromutilins, potentiated sulphonamides and tetracyclines. The prevalence of isolates categorised as NWT for five or more classes of antimicrobials was greater among NCC than CC isolates for both time periods, and increased with time. This study used standardised methods to identify significant shifts in antimicrobial resistance phenotypes of S. suis isolated from pigs in England, not only over time but also between isolates from known clinical cases or disease-free pigs.

The objective of this study was to determine the frequency of recommendation of adjuvant chemotherapy by UK-based general veterinary practitioners (GVPs) for canine patients with high-grade mast cell tumours (HGMCTs), splenic haemangiosarcomas (SHSs) and appendicular osteosarcomas (AOSs); to determine which chemotherapeutic protocols are used by GVPs; and to evaluate reasons why chemotherapy may or may not be recommended postoperatively. An internet survey was created in 2013 using an online programme and was distributed to GVPs. Questions relating to the use of adjuvant chemotherapy for three tumours were selected. In total, 300 responses were generated. Surgery was seen as primary therapy by most GVPs for HGMCT (91 per cent) and SHS (88 per cent), but less frequently for AOS (59 per cent). Also, 90, 40 and 57 per cent of respondents recommended adjuvant chemotherapy for HGMCT, SHS and AOS, respectively. Of these, an appropriate chemotherapy protocol was not known by 25, 51 and 36 per cent of GVPs for HGMCT, SHS and AOS, respectively. From the GVPs not recommending chemotherapy, 29, 64 and 66 per cent did not believe chemotherapy to be efficacious for these tumours. The frequency of recommendation regarding postoperative chemotherapy is variable by tumour type. Reasons given why postoperative chemotherapy is not recommended also vary by tumour type.

We have investigated, using micro-photoluminescence, the quantum confined Stark effect in an In(x)Ga(1-x)N/GaN multi-quantum disk structure at the tip of a single GaN nanorod. A strong and sharp emission line from the In(x)Ga(1-x)N/GaN quantum disks near 3.26 eV was observed. The peak energy of the emission line was observed to blue-shift with increasing excitation power, indicating a quantum confined Stark effect. Furthermore, both the blue-shift and the intensity of the emission saturate with increasing excitation power. The temperature-dependence of the 3.26 eV emission line has also been investigated.

Time-integrated and time-resolved microphotoluminescence studies have been performed on In x Ga 1 - x N quantum disks at the tips of GaN nanocolumns. The results are analyzed in the context of current theories regarding an inhomogeneous strain distribution in the disk which is theorized to generate lateral charge separation in the disks by strain induced band bending, an inhomogeneous polarization field distribution, and Fermi surface pinning. It is concluded that no lateral separation of carriers occurs in the quantum disks under investigation. Internal field screening by an increased carrier density in the QDisks at higher excitation densities is observed via a blue-shift of the emission and a dynamically changing decay time. Other possible explanations for these effects are discussed and discounted. Cathodoluminescence studies have also been carried out on the nanocolumns to provide insight into the physical origin of the luminescence. © 2011 American Institute of Physics.

Microphotoluminescence with one-photon and two-photon excitation has been employed to investigate localisation centres found in nanorod array LEDs. Quantum dot-like features with spectral width less than 1 meV were observed originating from low dimensional carrier confinement within the nanorods. Two-photon excitation was used to probe the individual localisation centres. The narrow peak PL energy does not shift with increasing excitation density, but rather an increase of discrete new peaks on the high energy side of the spectrum is observed. There is no temperature dependent emission energy shift observed from 4.3 K to 25 K. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

We investigated the carrier transition properties of the GaN/InGaN/GaN single quantum well bounded by AlGaN barriers. In order to confirm the carrier transition coming from the single quantum well, the single quantum well layer was etched by reactive ion etching method. The structural property of the samples was characterized by high resolution X-ray diffraction measurements. In micro-photoluminescence measurements, it is clearly shown that the donor bound exciton transition of the single quantum well sample was redshifted compared to the etched one due to strain. Moreover, a lot of peaks were observed below the GaN band gap energy due to carrier localization in the InGaN/GaN single quantum well, including carrier localization center and quantum confined states. The excitation power dependence and time resolved photoluminescence spectra were investigated to characterize the optical transition of the single quantum well© 2011 Elsevier B.V. All rights reserved.

The optical properties of GaN nanocolumns containing pairs of In xGa 1-xN (x ∼ 0.1) quantum disks (QDisks) have been experimentally measured. Strain simulations reveal an inhomogeneous distribution of strain, and furthermore, a relaxation between successive QDisks along the growth direction of the column. Although this inhomogeneous distribution of strain may indicate a lateral separation of carriers in the QDisk, the decay lifetime of the emission suggests far less carrier separation. The quantum confined stark effect is found to create an inhomogeneous distribution of charge within the QDisks along the growth direction of the rod. © 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim.

A presentation by Dr Mark Holmes from EBVM Skills Day 2015, London.

We report and discuss the origins of linearly polarized single photon emission from site-controlled GaN nanowire quantum dots. The observed single photon emission reveals almost complete linear polarization, in agreement with studies in the literature, which could be of use for applications such as quantum key distribution.

In addition to being an important human pathogen, Staphylococcus aureus is able to cause a variety of infections in numerous other host species. While the S. aureus strains causing infection in several of these hosts have been well characterised, this is not the case for companion rabbits (Oryctolagus cuniculus), where little data are available on S. aureus strains from this host. To address this deficiency we have performed antimicrobial susceptibility testing and genome sequencing on a collection of S. aureus isolates from companion rabbits. The findings show a diverse S. aureus population is able to cause infection in this host, and while antimicrobial resistance was uncommon, the isolates possess a range of known and putative virulence factors consistent with a diverse clinical presentation in companion rabbits including severe abscesses. We additionally show that companion rabbit isolates carry polymorphisms within dltB as described as underlying host-adaption of S. aureus to farmed rabbits. The availability of S. aureus genome sequences from companion rabbits provides an important aid to understanding the pathogenesis of disease in this host and in the clinical management and surveillance of these infections.

We propose a pairwise procedure to test the Feldstein–Horioka condition of capital mobility. In contrast to the existing approach, we explicitly examine the relationship between domestic investment and foreign savings rather than domestic savings. In terms of addressing the Feldstein–Horioka puzzle, our results based on a panel of OECD and emerging market economies initially suggest that the depth and extent of capital mobility remain generally limited and that mobility has increased over the past 20 years. However, in contrast to existing studies, we find that capital mobility between Euro and EU pairs is more extensive than between pairs that involve other countries. If our sample is expanded to include emerging markets, we find that capital mobility has also increased though is weaker than for OECD economies. We provide additional insight in terms of consistency between our assessment of capital mobility based on the Feldstein–Horioka condition (a quantity approach) and a price approach based on real interest rate differentials. © 2015, Springer-Verlag Berlin Heidelberg.

In this chapter we derive numerical methods to solve the first-order differential equation $$\displaystyle{ \frac{dy} {dt} = f(t,y),\;\;\text{ for }\;0

This chapter provides a brief introduction to the floating-point number system used in most scientific and engineering applications. A few examples are given in the next section illustrating some of the challenges using finite precision arithmetic, but it is worth quoting Donald Knuth to get things started. If you are unfamiliar with him, he was instrumental in the development of the analysis of algorithms, and is the creator of TeX. Anyway, here are the relevant quotes (Knuth [1997]

In this chapter one of the more common mathematical problems is studied, which is to find the solution, or solutions, of an equation of the form f(x) = 0. To illustrate the situation, we begin with a few examples.

Background: The recently isolated MRSA LGA251 has low resistance and carries a new mecA homolog. Results: PBP2ALGA, the protein product of the new mecA, showed a “preference” for penicillins and instability at 37 °C. mecALGA251 introduced into susceptible S. aureus allowed expression of high-level resistance. Significance: This study provides insights into the relationship between structure and function of PBP2A-like proteins., Methicillin-resistant Staphylococcus aureus (MRSA) strains show strain-to-strain variation in resistance level, in genetic background, and also in the structure of the chromosomal cassette (SCCmec) that carries the resistance gene mecA. In contrast, strain-to-strain variation in the sequence of the mecA determinant was found to be much more limited among MRSA isolates examined so far. The first exception to this came with the recent identification of MRSA strain LGA251, which carries a new homolog of this gene together with regulatory elements mecI/mecR that also have novel, highly divergent structures. After cloning and purification in Escherichia coli, PBP2ALGA, the protein product of the new mecA homolog, showed aberrant mobility in SDS-PAGE, structural instability and loss of activity at 37 °C, and a higher relative affinity for oxacillin as compared with cefoxitin. The mecA homolog free of its regulatory elements was cloned into a plasmid and introduced into the background of the β-lactam-susceptible S. aureus strain COL-S. In this background, the mecA homolog expressed a high-level resistance to cefoxitin (MIC = 400 μg/ml) and a somewhat lower resistance to oxacillin (minimal inhibitory concentration = 200 μg/ml). Similar to PBP2A, the protein homolog PBP2ALGA was able to replace the essential function of the S. aureus PBP2 for growth. In contrast to PBP2A, PBP2ALGA did not depend on the transglycosylase activity of the native PBP2 for expression of high level resistance to oxacillin, suggesting that the PBP2A homolog may preferentially cooperate with a monofunctional transglycosylase as the alternative source of transglycosylase activity.