132 research outputs found
Formative feedback to improve learning on a teacher education degree using a personal learning environment
This paper reports on an action research project involving a structured, formative assessment feedback process, within a personal learning environment (PLE), to address concerns about effectiveness of previous course delivery. The project ran during session 2006-07 involving the use of a series of tutor mediated self and peer assessed core tasks associated with five distinct learning milestones. These were associated with identifiable blocks of lectures delivered by different staff involved in the programme. The series of Core Tasks placed progressively increasing demands on students so helping them develop more sophisticated learning skills as the year progresses. The PLE is used as the medium for self/peer assessment processes and for tutor feedback and mediation
A t(11;15) fuses MLL to two different genes, AF15q14 and a novel gene MPFYVE on chromosome 15
The mixed lineage leukemia gene (MLL, also known as HRX, ALL-1 and Htrx) located at 11q23 is involved in translocations with over 40 different chromosomal bands in a variety of leukemia subtypes. Here we report our analysis of a rare but recurring translocation, t(11;15)(q23;q14). This translocation has been described in a small subset of cases with both acute myeloblastic leukemia and ALL. Recent studies have shown that MLL is fused to AF15q14 in the t(11;15). Here we analyse a sample from another patient with this translocation and confirm the presence of an MLL-AF15q14 fusion. However, we have also identified and cloned another fusion transcript from the same patient sample. In this fusion transcript, MLL is fused to a novel gene, MLL partner containing FYVE domain (MPFYVE). Both MLL-AF15q14 and MLL-MPFYVE are in-frame fusion transcripts with the potential to code for novel fusion proteins. MPFYVE is also located on chromosome 15, approximately 170 kb telomeric to AF15q14. MPFYVE contains a highly conserved motif, the FYVE domain which, in other proteins, has been shown to bind to phosphotidyl-inositol-3 phosphate (PtdIns(3)P). The MLL-MPFYVE fusion may be functionally important in the leukemia process in at least some patients containing this translocation
Temperature and relative humidity trends in the northernmost region of South Africa, 1950–2016
The northernmost Limpopo Province is located in one of the warmest regions of South Africa, where
the agricultural sector is prone to heat stress. The aim of this study was to explore air temperature
and relative humidity trends for the region, which have implications for agricultural adaptation and
management (amongst other sectors). In particular, we investigated seasonal, annual and decadal scale
air temperature and relative humidity changes for the period 1950–2016. Positive temperature trends
were recorded for this period, averaging +0.02 °C/year, with the strongest changes observed in mean
maximum summer temperatures (+0.03 °C/year). Interannual temperature variability also increased over
time, especially for the period 2010–2016, which presents probability densities of <50% for minimum
temperatures. Positive relative humidity trends (+0.06%/year) were also recorded for the period 1980–
2016, but proved to be the least predictable weather parameter, with probability densities of <0.5%
across seasons for the study period. Considering the substantial interannual variability in temperature
and relative humidity, there is clear increased risk for the agricultural sector, particularly for small-scale
farmers who generally have limited capacity to adapt. Climate science focusing on the southern African
region should continue to establish the impact of climate change and variability on specific small-scale
farming systems and enterprises, with recommendations for strategic adaptation based on up-to-date
evidence.
SIGNIFICANCE :
• Heat indices have increased, and variability in temperature and relative humidity has substantially
increased over recent decades.
• Changes in air temperature and relative humidity have direct and/or indirect negative effects on sectors
such as agriculture, leading to reduced productivity.
• The small-scale farming sector, which contributes significantly to national food security in developing
countries, is the production system most exposed and vulnerable to observed changes/extremes in
temperature and relative humidity.
• There is an urgent need to build capacity of small-scale farmers for appropriate adaptation to observed
changes in climate based on up-to-date evidence.Open Society Foundationhttp://www.sajs.co.zahj2021Geography, Geoinformatics and Meteorolog
Perceived impacts of climate change on rural poultry production : a case study in Limpopo Province, South Africa
Rural farming households in developing countries frequently contend with multiple challenges, including a lack of resources, food insecurity, and poverty. Climate change threatens to compound existing challenges, particularly in such rural subsistence economies with limited adaptive capacity. We aim to establish farmers' perspectives on likely impacts of climate change on their rural poultry production in northern South Africa. A baseline questionnaire-based study was conducted across 106 households in the town of Musina, South Africa. Most households lacked reliable and adequate sources of income and had, for example, days when they had to skip meals as a coping strategy. With such poverty, coupled with poor access to scientific information on agricultural production, these farmers typically have limited capacity to adapt to shocks such as climate variability and change. Farmers reported a reduction in poultry productivity in recent years, coinciding with increased ambient temperatures. There are concerns that recent and ongoing warming trends will have negative impacts on the future growth and wellbeing of birds. However, the farmers in our study perceived their poultry as hardy and well adapted to survive any future climatic changes and may be uninclined to take adaptive action at this stage.The Global Change Institute, University of the Witwatersrand Johannesburg.http://www.tandfonline.com/toc/tcld20hj2023Geography, Geoinformatics and Meteorolog
On Black Hole Detection with the OWL/Airwatch Telescope
In scenarios with large extra dimensions and TeV scale gravity ultrahigh
energy neutrinos produce black holes in their interactions with the nucleons.
We show that ICECUBE and OWL may observe large number of black hole events and
provide valuable information about the fundamental Planck scale and the number
of extra dimensions. OWL is especially well suited to observe black hole events
produced by neutrinos from the interactions of cosmic rays with the 3 K
background radiation. Depending on the parameters of the scenario of large
extra dimensions and on the flux model, as many as 28 events per year are
expected for a Planck scale of 3 TeV.Comment: 8 pages, including 7 color figures, three figure captions corrected,
minor changes for clarification, one reference adde
Biomolecular transitions and lipid accumulation in green microalgae monitored by FTIR and Raman analysis
Fourier transform infrared (FTIR) and Raman spectroscopic techniques were employed to analyze the biomolecular transitions and lipid accumulation in three freshwater green microalgal species, Monoraphidium contortum (M. contortum), Pseudomuriella sp. and Chlamydomonas sp. during various phases of their growth. Biomolecular transitions and lipid [hydrocarbons, triacylglycerides (TAGs)] accumulation within the microalgal cells were identified using second derivatives of the FTIR absorption spectroscopy. Second derivative analysis normalized and resolved the original spectra and led to the identification of smaller, overlapping bands. Both relative and absolute content of lipids were determined using the integrated band area. M. contortum exhibited higher accumulation of lipids than the other two species. The integrated band area of the vibrations from saturated (SFA) and unsaturated lipids (UFA) enabled quantification of fatty acids. The percentage of SFA and UFA was determined using GC, FTIR and Raman spectroscopy. From the spectral data, the order of increasing concentration of SFA among the three microalgal species was M. contortum > Chlamydomonas sp. > Pseudomuriella sp. The spectral results on fatty acids were consistent with the separation of lipids by gas chromatography. The results emphasized the significance of FTIR and Raman spectroscopic methods in monitoring the biomolecular transitions and rapid quantification of lipids, without the need for extraction of lipids
One-loop Correction and the Dilaton Runaway Problem
We examine the one-loop vacuum structure of an effective theory of gaugino
condensation coupled to the dilaton for string models in which the gauge
coupling constant does not receive string threshold corrections. The new
ingredients in our treatment are that we take into account the one-loop
correction to the dilaton K\"ahler potential and we use a formulation which
includes a chiral field corresponding to the gaugino bilinear. We find
through explicit calculation that supersymmetry in the Yang-Mills sector is
broken by gaugino condensation.
The dilaton and field have masses on the order of the gaugino
condensation scale independently of the dilaton VEV. Although the calculation
performed here is at best a model of the full gaugino condensation dynamics,
the result shows that the one-loop correction to the dilaton K\"ahler potential
as well as the detailed dynamics at the gaugino condensation scale may play an
important role in solving the dilaton runaway problem.Comment: 19 page
Multiplicativity of completely bounded p-norms implies a new additivity result
We prove additivity of the minimal conditional entropy associated with a
quantum channel Phi, represented by a completely positive (CP),
trace-preserving map, when the infimum of S(gamma_{12}) - S(gamma_1) is
restricted to states of the form gamma_{12} = (I \ot Phi)(| psi >< psi |). We
show that this follows from multiplicativity of the completely bounded norm of
Phi considered as a map from L_1 -> L_p for L_p spaces defined by the Schatten
p-norm on matrices; we also give an independent proof based on entropy
inequalities. Several related multiplicativity results are discussed and
proved. In particular, we show that both the usual L_1 -> L_p norm of a CP map
and the corresponding completely bounded norm are achieved for positive
semi-definite matrices. Physical interpretations are considered, and a new
proof of strong subadditivity is presented.Comment: Final version for Commun. Math. Physics. Section 5.2 of previous
version deleted in view of the results in quant-ph/0601071 Other changes
mino
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