Item statistics derived from three-option versions of multiple-choice questions are usually as robust as four- or five-option versions: implications for exam design.

Different versions of multiple-choice exams were administered to an undergraduate class in human physiology as part of normal testing in the classroom. The goal was to evaluate whether the number of options (possible answers) per question influenced the effectiveness of this assessment. Three exams (each with three versions) were given to each of two sections during an academic quarter. All versions were equally long, with 30 questions: 10 questions with 3 options, 10 questions with 4, and 10 questions with 5 (always one correct answer plus distractors). Each question appeared in all three versions of an exam, with a different number of options in each version (three, four, or five). Discrimination (point biserial and upper-lower discrimination indexes) and difficulty were evaluated for each question. There was a small increase in difficulty (a lower average score on a question) when more options were provided. The upper-lower discrimination index indicated a small improvement in assessment of student learning with more options, although the point biserial did not. The total length of a question (number of words) was associated with a small increase in discrimination and difficulty, independent of the number of options. Quantitative questions were more likely to show an increase in discrimination with more options than nonquantitative questions, but this effect was very small. Therefore, for these testing conditions, there appears to be little advantage in providing more than three options per multiple-choice question, and there are disadvantages, such as needing more time for an exam

Globalization and land-use transitions in Latin America

Current socioeconomic drivers of land-use change associated with globalization are producing two contrasting land-use trends in Latin America. Increasing global food demand (particularly in Southeast Asia) accelerates deforestation in areas suitable for modern agriculture (e.g., soybean), severely threatening ecosystems, such as Amazonian rain forests, dry forests, and subtropical grasslands. Additionally, in the coming decades, demand for biofuels may become an emerging threat. In contrast, high yields in modern agricultural systems and rural–urban migration coupled with remittances promote the abandonment of marginal agricultural lands, thus favoring ecosystem recovery on mountains, deserts, and areas of poor soils, while improving human well-being. The potential switch from production in traditional extensive grazing areas to intensive modern agriculture provides opportunities to significantly increase food production while sparing land for nature conservation. This combination of emerging threats and opportunities requires changes in the way the conservation of Latin American ecosystems is approached. Land-use efficiency should be analyzed beyond the local-based paradigm that drives most conservation programs, and focus on large geographic scales involving long-distance fluxes of products, information, and people in order to maximize both agricultural production and the conservation of environmental services.Fil: Grau, Hector Ricardo. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; ArgentinaFil: Mitchell, Aide. Universidad de Puerto Rico; Puerto Ric

Lanthanide Soil Chemistry and Its Importance in Understanding Soil Pathways: Mobility, Plant Uptake, and Soil Health

The lanthanide elements or rare earth elements (REEs) are an active soil science research area, given their usage as micro-fertilizers, documented cases of environmental impact attributed to industry/mining, and their ability to identify lithologic discontinuities and reveal active soil processes. To fully understand REEs requires an understanding of their chemical reactivity, both for the individual elements and their behavior as a group of elements. The elements of the lanthanide series, including La and Y, may have subtle to very perceptible chemical differences that when viewed collectively reveal information that gives emphasis to soil processes that clarify soil behavior or soil genesis. This chapter concentrates on lanthanide soil chemistry and shows how the soil chemistry of REEs may support soil science investigations

'A Foras, Out': youth antimilitarism engagement in Sardinia

This paper presents a short review of the A Foras, Out movement in Sardinia and examines its youth branch, the student collective (Collettivo studentesco) for university and high school students. Since the late 1960s, grassroots movements, associations, committees, political groups, antimilitarists and ecologists have struggled against land occupation by NATO and other military forces and called for the drastic reduction or elimination of military activities on the island that was later related to the emergence of environmental risk and diseases. By participating in networked collective actions, these young activists reclaim the land occupied by the military and elaborate a legitimisation-based political rhetoric that undermines the legality of the presence of military bases in Sardinia. The young activists emerge as social actors in engaging debates within the movement about of civil disobedience practices that sometimes cross the boundary of illegal practices (e.g. cutting fences around military areas to stop training). Their engagement pushes the actions of the senior non-violent antimilitarist activists into a new, not yet defined practice of antimilitarism incorporating diverse political platforms: from independence movements to traditional workerism, anarchists to radical left-wing movements. We analyse the youth group's agency in transforming antimilitarism from general pacifism into a mixed antimilitarist-eco, neo-independence movement calling for new regional sovereignty

Inkjet printing multifunctional chromatic sensors and chromism study

The thermochromism and chemochromism of polydiacetylene (PDAs) and PDA/ZnO nano composites have been systematically studied by attentuated total reflection (ATR)- Fourier transform infrared (FTIR), temperature-dependent Raman, colorimetric (using optical densitometry) and differential scanning calorimetry (DSC). Reversibility of PDAs has been enhanced by the formation of chelation between the carboxylic groups on side chain of diacetylene and Zn ion. The thermochromatic transition temperature increases with the concentration of ZnO. Thin films of polydiacetylene (PDAs) and PDA/ZnO nanocomposites have been successfully fabricated by inkjet printing both solution type and suspension type ink. Results suggest that PDA monomers are well-aligned and closely packed following printing. By modifying the particle size of PDA monomers or the diacetylene/ZnO particle size, reversible PDA ink with wider range of ZnO concentration and longer shelf life could be obtained by using water based ink. Also, with inkjet printing technology, thin film of PDA and PDA/ZnO composites could be deposited on different substrate materials, such as paper, Kapton and Mylar film. In order to further study alkyl side chain effect on the sensitivity of PDA, Density Function Theory (DFT) simulation is conducted, and the results show that the torsion of C-C bond is closely related to the length of the alkyl side chain

A Large-Scale Wetland Conversion Project in Southeastern Missouri: Sustainability of Water and Soil

Wetland conversion in southeastern Missouri initiated with the Little River Drainage Project (1914–1924) resulting in the permanent drainage and conversion of 5 million acres (2 million hectares) to productive agricultural land. Given that this ancestral wetland conversion has totally replaced the wetland ecosystem with prime agricultural land and with this conversion, the loss of wildlife habitat is nearly complete, the question remains what actions are now possible to restore key wetland soil pathways to support soil health and water quality. Key to any corrective practices involves agricultural producer involvement and commitment. The emerging concept of soil health supports the use of cover crops that promote soil structure development and soil carbon sequestration, each perceived as supporting farm profitability. Government programs supporting field flooding during the off-season supports migratory water fowl. Farming practices such as furrow irrigation and allied technologies for rice production limit aquifer overdraft. Edge of field technology involving riparian strips and denitrification bioreactors support down-stream water quality by limiting nitrate and phosphate off-field migration. The result is that emerging technologies (i) support farm profitability and environmental stewardship and (ii) which are designed specifically to provide farming practice compatibility with the soil and water resources re-establishes some wetland mechanisms appropriate for long-term land and water resource sustainability

Entrepreneurship Education In Nigeria.

This paper discusses the need for entrepreneurship education in Nigeria geared towards enhancing sustainable development in the country. Since entrepreneurship skills remain vital in the real sector and the sustenance of economic development, it has become imperative for government to pay attention to this sub-sector. The problems facing the country ranging from acute poverty, youth and graduate unemployment, dependence on foreign goods and technology; to very low economic growth and development among others has prompted government’s recognition of this fact that has led to the introduction of entrepreneurial studies in tertiary institutions. This paper therefore argues that entrepreneurship education will equip the students with the skills with which to be self-reliant. The objective and strategies for re-designing entrepreneurship education are also discussed. The paper recommends that educational programmes at all levels of education should be made relevant to provide the youth the needed entrepreneurial skills. Keywords: Entrepreneurship Education, Vocational Training, Sustainable Development, Entrepreneur, Education

Assessment of humoral and cellular immune responses of the RTS,S/AS02D malaria vaccine candidate administered to infants living in a malaria endemic area in Mozambique

MSc (Med), Faculty of Health Sciences, University of the Witwatersrand, 2009Background: RTS,S candidate malaria vaccine has been shown to be highly immunogenic in children and infants, but the protective immune mechanisms still remain to be clearly elucidated. It is believed that RTS,S elicits a strong neutralizing humoral immune response directed against surface-exposed sporozoite proteins and cell mediated immune (CMI) responses characterized by predominantly CD4+ Th1 cells. The objective of this study was to investigate humoral and cell-mediated immune responses to the RTS,S/AS02D malaria vaccine and its association with protection against infection and disease by P. falciparum. Methodology and Principal Findings: This secondary data analysis from data of a phase I/IIb randomized, double-blind, controlled trial, included 154 healthy infants living in rural Mozambique, previously immunized with RTS,S/AS02D candidate malaria vaccine or the control Engerix-B™ vaccine. Antibodies against circumsporozoite protein (CSP) and hepatitis-B surface antigen (HBsAg) were measured with a standard ELISA. Fresh blood intracellular staining assay was performed to evaluate the expression of IL-2 and IFN-γ by CD4+ and CD8+ cells in response to in vitro stimulation of specific peptides. Data was evaluated for association with the risk of malaria detected by both active and passive case detection of infection over a period of 6 months post dose 3. Anti-HBs antibody geometric mean titers declined from 10,082 mIU/mL one month post Dose 3 to 2,751 mIU/mL at 12 months post Dose 3 in the RTS,S/AS02D group; anti-HBs v geometric mean titers were 392.4 mIU/mL and 263.9 mIU/mL, respectively in the Engerix- BTM group. Anti-CSP antibody geometric mean titers declined from 199.9 EU/mL one month post Dose 3 to 7.3 EU/mL at 12 months post Dose 3 in the RTS,S/AS02D group. Median stimulation indices of HBs-specific IL-2 and IFN-γ producing CD8+ T cells was higher in the RTS,S/AS02D group than in control group (Wilcoxon rank sum p-values for IFN-γ = 0.015, for IL-2 = 0.030) at 10.5 weeks post immunization. Median stimulation indices of anti-CSP specific IFN-γ producing CD8+ T cells at the same time point was 1.13 (IQR: 0.79 - 1.67; p=0.029). For specific IL-2-producing CD4+ T cells, the median SI was 1.14 (IQR: 0.74 – 1.60, p=0.043) at 10.5 weeks post dose three. The reduction in hazards of malaria infection were 18.3 % (95% CI: -267.9 – 81.8, p=0.793) and -12.0 % (95% CI: -295 – 68.2, p=0.86) for specific IL-2 CD4+ stimulation indices; For specific CD8+ IFN-γ stimulation indices the hazards were -103.6% (95% CI: -690.9 – 47.6; p=0.305) and 48.8% (95% CI: -97.0 – 86.7; p=0.33) at four and 10.5 weeks post immunization respectively. Conclusion: The RTS,S/AS02D vaccine was immunogenic and has elicited detectable levels of CSP specific cell mediated responses. No evidence of association was found between the antibodies anti-CSP and specific cell mediated responses and the risk of malaria