AS/A Level Science & Art Competition: Particle Physics

A video made by physics for the AS/A Level Science & Art Competition

Review of A-level Chemistry content 2015

ITEM DESCRIPTION After producing reviews of A-level Chemistry content in 2007 and 2010, we have updated the document to reflect the changes which have been introduced for first teaching in September 2015. We will be working with our network of teachers locally to monitor the impacts of the changes on teaching and the student experience with a view to releasing an updated version in the summer of 2017. This will aim to provide insights for university staff regarding the experiences of incoming students who will have been in the first cohort to have studied the new specifications. We are grateful to the Royal Society of Chemistry for support for the final stages of compiling this report. If you spot any errors or omissions, please don't hesitate to contact us.

Plasmodium vivax lineages: geographical distribution, tandem repeat polymorphism, and phylogenetic relationship

Background: Multi-drug resistance and severe/ complicated cases are the emerging phenotypes of vivax malaria, which may deteriorate current anti-malarial control measures. The emergence of these phenotypes could be associated with either of the two Plasmodium vivax lineages. The two lineages had been categorized as Old World and New World, based on geographical sub-division and genetic and phenotypical markers. This study revisited the lineage hypothesis of P. vivax by typing the distribution of lineages among global isolates and evaluated their genetic relatedness using a panel of new mini-satellite markers. Methods: 18S SSU rRNA S-type gene was amplified from 420 Plasmodium vivax field isolates collected from different geographical regions of India, Thailand and Colombia as well as four strains each of P. vivax originating from Nicaragua, Panama, Thailand (Pak Chang), and Vietnam (ONG). A mini-satellite marker panel was then developed to understand the population genetic parameters and tested on a sample subset of both lineages. Results: 18S SSU rRNA S-type gene typing revealed the distribution of both lineages (Old World and New World) in all geographical regions. However, distribution of Plasmodium vivax lineages was highly variable in every geographical region. The lack of geographical sub-division between lineages suggests that both lineages are globally distributed. Ten mini-satellites were scanned from the P. vivax genome sequence; these tandem repeats were located in eight of the chromosomes. Mini-satellites revealed substantial allelic diversity (7-21, AE = 14.6 +/- 2.0) and heterozygosity (He = 0.697-0.924, AE = 0.857 +/- 0.033) per locus. Mini-satellite comparison between the two lineages revealed high but similar pattern of genetic diversity, allele frequency, and high degree of allele sharing. A Neighbour-Joining phylogenetic tree derived from genetic distance data obtained from ten mini-satellites also placed both lineages together in every cluster. Conclusions: The global lineage distribution, lack of genetic distance, similar pattern of genetic diversity, and allele sharing strongly suggested that both lineages are a single species and thus new emerging phenotypes associated with vivax malaria could not be clearly classified as belonging to a particular lineage on basis of their geographical origin.

Citizen safety at local level: fieldwork notes on performance and perception of the ‘Quadrant Plan’ in Cali (Colombia)

This article summarizes field notes related to the study of the actions performed by the Metropolitan Police of Santiago de Cali in the context of its ‘Plan Cuadrante’ (a micro-local security action plan) and the citizen’s perception towards it. Taking an ethnographic approach, it places special emphasis on the actions that imply identifying the main criminal and violent actors and activities. The study focuses on four local districts of the city: El Cortijo, Mariano Ramos, Terrón Colorado y Villa del Lago.

Frequency of Low-level Mosaicism in X-Cromosome in Couples with Antecedent of Recurrent Miscarriages

Recurrent miscarriage occurs in around 1 to 7 percent of couples. The etiology involves genetic, immunologic, anatomic, hormonal, metabolic, thrombophilic and infectious factors. With the aim of establishing the frequency of low-level mosaicism in the X-chromosome, in a population of couples with prior recurrent miscarriages, a prospective case-control cytogenetic study took place on 20 couples, at the biogenetic laboratory in CECOLFES (Colombian Center of Fertility and Sterility). Clinical pathologic evaluation, anatomic, hormonal, infectious, andrologic and genetic studies were performed. As a conventional method in cytogenetic techniques, banding GTG was used for the study of structural and numeric chromosomal abnormalities whereas the molecular method of Fluorescence In Situ Hybridization (FISH) was used to confirm the mosaicism in sexual chromosomes. According to paraclinic results from the participating couples, diagnosis showed immunologic (75%), anatomic (30%), hormonal (25%), male (25%), infectious (25%), genetic (15%) and idiophatic factors (10%). Results from the cytogenetic analysis, were 10% of low-level mosaicism in the X-chromosome in two women whose final diagnosis included genetic and infectious factors for one and genetic and immunologic factors for the other. Only 10 % of the total miscarriages from the couples were evaluated. Conclusions include aspects such as multifactorial evidence of pathogenesis in recurrent miscarriage, the sub-diagnosis of genetic factors and the need to focus future investigations on cytogenetic interpretation and the clinicalpathological association between low-level mosaicism in the X-cromosome and recurrent miscarriage.

Land Reform, Latifundia and Social Development at Local Level in Colombia, 1961-2010

The paper analyzes the effects of land reform on social development – poverty and land distribution-at the local level. Land reform in Colombia, understood as the allocation of public land to peasant, has granted 23 million hectares which comprises around 20% of Colombian territory and about 50% of usable productive land. Theoretically, the net impact of land reform on development is the combination of a poverty effect and a land distribution effect. Our findings suggest that land reform from 1961 onwards has slightly reduced poverty and mildly improved land distribution. Nonetheless,municipalities with strong presence of latifundia prior to1961 have experienced both a slower drop in poverty and a weaker improvement of land distribution .This paper finds that prevalence of latifundia partially offset the positive effect of land reform in promoting social development.