Topics in relativistic cosmology: Cosmology on the past lightcone and in modified gravitation

The lightcone gauge is a set of what are called the observational coordinates adapted to our past lightcone. We develop this gauge by producing a perturbed spacetime metric that describes the geometry of our past lightcone where observations are usually obtained. We then connect the produced observational metric to the perturbed Friedmann-Lemaître-Robertson-Walker metric in the standard general gauge or what is the so-called 1+3 gauge. We derive the relations between these perturbations of spacetime in the observational coordinates and those perturbations in the standard metric approach, as well as the dynamical equations for the perturbations in observational coordinates. We also calculate the observables in the lightcone gauge and rederive them in terms of Bardeen potentials to first order. A verification is made of the observables in the perturbed lightcone gauge with those in the standard gauge. The advantage of the method developed is that the observable relations are simpler than in the standard formalism. We use the perturbed lightcone gauge in galaxy surveys and galaxy number density contrast. The significance of the new gauge is that by considering the null-like light propagations, the calculations are much simpler since angular deviations are not considered. Standard cosmology based on General Relativity is generally believed to have serious shortcomings, such as the unexplained issues of dark matter and dark energy. As a remedy, many alternative theories of gravitation have been proposed over the years, one of which is ƒ(R) gravity. We explore classes of irrotational-fluid cosmological models in the context of ƒ(R) gravity in an attempt to put some theoretical and mathematical restrictions on the form of the ƒ(R) gravitational Lagrangian. In particular, we investigate the consistency of the linearised dust models for shear-free cases as well as in the limiting cases when either the gravito-magnetic or gravito-electric components of the Weyl tensor vanish. We also discuss the existence and consistency of classes of non-expanding irrotational spacetimes in ƒ(R)-gravity. Furthermore, we explore exact ƒ(R) gravity solutions that mimic Chaplygin-gas inspired ΛCDM cosmology. Starting with the original, generalized and modified Chaplygin gas equations of state, we reconstruct the forms of ƒ(R) Lagrangians. The resulting solutions are generally quadratic in the Ricci scalar, but have appropriate ΛCDM solutions in limiting cases. These solutions, given appropriate initial conditions, can be potential candidates for scalar field-driven early universe expansion (in ation) and dark energy-driven late-time cosmic acceleration

On the Acquisition of Derivational Suffixes by Kuwaiti EFL Learners

This study aims to test the extent to which 90 Kuwaiti EFL learners are aware of the correct use of derivational suffixes in English. It also identifies the mains reasons of the errors that Kuwaiti EFL learners may make. In addition, it investigates whether the English proficiency level of the participants plays a role in their answers on the test. To this end, the participants were tested twice in this study; a multiple-choice test was used to check their comprehension skills, whereas a fill-in the blank test was used to measure their ability to produce the correct derivational suffixes in English. Following data analysis, the results reveal that Kuwaiti EFL learners are fairly aware of the correct use of English derivational suffixes to a certain degree; the total mean on both tests (comprehension = 70% and production = 56%) is 63%. The participants obtained higher percentage of correct answers on the comprehension test (mean= 70%) compared to the production test (mean = 56%). Additionally, the t-test shows that the participants’ English proficiency level plays a central role in their comprehension and production of these suffixes. The performance of the Advanced Learners (ALs) (comprehension = 77% and production = 62%) is better than that of the Intermediate Learners (ILs) (comprehension = 64% and production = 48%) on the tests. In particular, there is a statistically significant difference between the answers of ALs and ILs on both tests. Regarding the types of error made by the participants, I argued that the most noticeable ones are due to: (1) the modification that non-neutral derivational suffixes cause when they are attached to the word (stems/roots); and (2) first language (L1) influence. Finally, the study concludes with some recommendations for further research

Customer Perceptions of Workplace Incivility in Singapore

Workplace incivility is found to be on the rise and exists widely in Asian workplaces. The combination of stress, less formal organisational structures and technological advancements has been found to contribute to a surge in workplace incivility. The negative effects of workplace incivility lead to problems in productivity, employee retention and service delivery. This exploratory study aims to examine whether workplace incivility is prevalent in 5-star hotels and premier restaurants in Singapore, from the perception of customers. Results of the conducted study show that customers see that workplace incivility is prevalent. Findings showed that co-workers did not greet or acknowledge each other during work and the critical service values of courtesy and friendliness were also not consistently demonstrated towards their internal or external guests. We suspect that key stakeholders within the hospitality and tourism industry in Singapore are unaware that workplace incivility can critically paralyse the ability of their staff to deliver excellent service and can hinder Singapore from achieving high ratings in the Customer Service Index

Cultural heritage communities: Technologies and challenges

This workshop will explore the role of technology support-ing and mediating cultural heritage practices for both pro-febional communities (cultural heritage profebionals, her-itage institutions, etc.) and civic communities (citizen-led heritage initiatives, heritage volunteers, personal and com-munity identified heritage, heritage crowdsourcing, etc.). The workshop-which aims to attract participants from her-itage studies and practice, community engagement, digital humanities and human-centred computing-will discub challenges and future opportunities for technology use and for design and participatory procebes in the context of var-ious heritage communities, and the role of different stake-holders in engaging with heritage in a technologically-mediated way

Analysis of socio-economic aspects of local and national organic farming markets

Final report for Defra, July 200

Expanding the neurological phenotype of ring chromosome 10 syndrome: A case report and review of the literature

Ring chromosome 10 [r(10)] syndrome is a rare genetic condition, currently described in the medical literature in a small number of case report studies. Typical clinical features include microcephaly, short stature, facial dysmorphisms, ophthalmologic abnormalities and genitourinary malformations. We report a novel case of r(10) syndrome and review the neurological and neuro-radiological phenotypes of the previously described cases. Our patient, a 3 year old Italian girl, represents the 20th case of r(10) syndrome described to date. Intellectual disability/developmental delay (ID/DD), microcephaly, strabismus, hypotonia, stereotyped/aggressive behaviors and elec-troencephalographic abnormalities were identified in our patient, and in a series of previous cases. A brain MRI disclosed a complex malformation involving both the vermis and cerebellar hemispheres; in the literature, posterior cranial fossa abnormalities were documented by CT scan in another case. Two genes deleted in our case (ZMYND11 in 10p and EBF3 in 10q) are involved in autosomal dominant neurodevelopmental disorders, characterized by different expressions of brain and posterior cranial fossa abnormalities, ID/DD, hypotonia and behavioral problems. Our case expands the neurological and neuroradiological phenotype of r(10) syndrome. Although r(10) syndrome represents an extremely rare condition, with a clinical characterization limited to case reports, the recurrence of specific neurological and neuroradiological features suggests the need for specific genotype-phenotype studies

Anti-tick microbiota vaccine impacts ixodes ricinus performance during feeding

The tick microbiota is a highly complex ensemble of interacting microorganisms. Keystone taxa, with a central role in the microbial networks, support the stability and fitness of the microbial communities. The keystoneness of taxa in the tick microbiota can be inferred from microbial co-occurrence networks. Microbes with high centrality indexes are highly connected with other taxa of the microbiota and are expected to provide important resources to the microbial community and/or the tick. We reasoned that disturbance of vector microbiota by removal of ubiquitous and abundant keystone bacteria may disrupt the tick-microbiota homeostasis causing harm to the tick host. These observations and reasoning prompted us to test the hypothesis that antibodies targeting keystone bacteria may harm the ticks during feeding on immunized hosts. To this aim, in silico analyses were conducted to identify keystone bacteria in the microbiota of Ixodes nymphs. The family Enterobacteriaceae was among the top keystone taxa identified in Ixodes microbiota. Immunization of a-1, 3-galactosyltransferase-deficient-C57BL/6 (a1, 3GT KO) mice with a live vaccine containing the Enterobacteriaceae bacterium Escherichia coli strain BL21 revealed that the production of anti-E. coli and anti-a-Gal IgM and IgG was associated with high mortality of I. ricinus nymphs during feeding. However, this effect was absent in two different strains of wild type mice, BALB/c and C57BL/6. This result concurred with a wide distribution of a-1, 3-galactosyltransferase genes, and possibly a-Gal, in Enterobacteriaceae and other bacteria of tick microbiota. Interestingly, the weight of I. ricinus nymphs that fed on E. coli-immunized C57BL/6 was significantly higher than the weight of ticks that fed on C57BL/6 immunized with a mock vaccine. Our results suggest that anti-tick microbiota vaccines are a promising tool for the experimental manipulation of vector microbiota, and potentially the control of ticks and tick-borne pathogens