Analysing Mathematical Abilities of High School Graduates

In this paper we are trying to differentiate the level of mathematical abilities of high school graduates in Bahrain schools. The mathematical abilities that we are trying to analyse are conceptual understanding, content knowledge and problemsolving skills. content understanding focusses on performing algorithms, while conceptual understanding focus on comprehending the concepts and relations. Problem solving needs both. We will prepare test items to measure graduates on different mathematics content domains. This research will try to identify students’ weaknesses in mathematical and suggest ways to improve the understanding in mathematics.     Keywords: Conceptual understanding; content knowledge; problem solving

7-O-methylpunctatin, a novel homoisoflavonoid, inhibits phenotypic switch of human arteriolar smooth muscle cells

Remodeling of arterioles is a pivotal event in the manifestation of many inflammation-based cardio-vasculopathologies, such as hypertension. During these remodeling events, vascular smooth muscle cells (VSMCs) switch from a contractile to a synthetic phenotype. The latter is characterized by increased proliferation, migration, and invasion. Compounds with anti-inflammatory actions have been successful in attenuating this phenotypic switch. While the vast majority of studies investigating phenotypic modulation were undertaken in VSMCs isolated from large vessels, little is known about the effect of such compounds on phenotypic switch in VSMCs of microvessels (microVSMCs). We have recently characterized a novel homoisoflavonoid that we called 7-O-methylpunctatin (MP). In this study, we show that MP decreased FBS-induced cell proliferation, migration, invasion, and adhesion. MP also attenuated adhesion of THP-1 monocytes to microVSMCs, abolished FBS-induced expression of MMP-2, MMP-9, and NF-?B, as well as reduced activation of ERK1/2 and FAK. Furthermore, MP-treated VSMCs showed an increase in early (myocardin, SM-22?, SM-?) and mid-term (calponin and caldesmon) differentiation markers and a decrease in osteopontin, a protein highly expressed in synthetic VSMCs. MP also reduced transcription of cyclin D1, CDK4 but increased protein levels of p21 and p27. Taken together, these results corroborate an anti-inflammatory action of MP on human microVSMCs. Therefore, by inhibiting the synthetic phenotype of microVSMCs, MP may be a promising modulator for inflammation-induced arteriolar pathophysiology. - 2019 by the authors. Licensee MDPI, Basel, Switzerland.Funding: This work was supported by the American University of Beirut (Grant # MPP 320133 to A.E.), University of Petra (Grant #: 5/4/2019) to A.B., E.B., and A.E., and the National Council for Scientific Research (CNRS) to M.F.Scopu

Unmasking the interplay between mTOR and Nox4: novel insights into the mechanism connecting diabetes and cancer

Cancer was recently annexed to diabetic complications. Furthermore, recent studies suggest that cancer can increase the risk of diabetes. Consequently, diabetes and cancer share many risk factors, but the cellular and molecular pathways correlating diabetes and colon and rectal cancer (CRC) remain far from understood. In this study, we assess the effect of hyperglycemia on cancer cell aggressiveness in human colon epithelial adenocarcinoma cells in vitro and in an experimental animal model of CRC. Our results show that Nox (NADPH oxidase enzyme) 4-induced reactive oxygen species (ROS) production is deregulated in both diabetes and CRC. This is paralleled by inactivation of the AMPK and activation of the mammalian target of rapamycin (mTOR) C1 signaling pathways, resulting in 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) accumulation, induction of DNA damage, and exacerbation of cancer cell aggressiveness, thus contributing to the genomic instability and predisposition to increased tumorigenesis in the diabetic milieu. Pharmacologic activation of AMPK, inhibition of mTORC1, or blockade of Nox4 reduce ROS production, restore the homeostatic signaling of 8-oxoguanine DNA glycosylase/8-oxodG, and lessen the progression of CRC malignancy in a diabetic milieu. Taken together, our results identify the AMPK/mTORC1/Nox4 signaling axis as a molecular switch correlating diabetes and CRC. Modulating this pathway may be a strategic target of therapeutic potential aimed at reversing or slowing the progression of CRC in patients with or without diabetes.-Mroueh, F. M., Noureldein, M., Zeidan, Y. H., Boutary, S., Irani, S. A. M., Eid, S., Haddad, M., Barakat, R., Harb, F., Costantine, J., Kanj, R., Sauleau, E.-A., Ouhtit, A., Azar, S. T., Eid, A. H., Eid, A. A. Unmasking the interplay between mTOR and Nox4: novel insights into the mechanism connecting diabetes and cancer.Scopu

The consequences of nuclear electron capture in core collapse supernovae

The most important weak nuclear interaction to the dynamics of stellar core collapse is electron capture, primarily on nuclei with masses larger than 60. In prior simulations of core collapse, electron capture on these nuclei has been treated in a highly parameterized fashion, if not ignored. With realistic treatment of electron capture on heavy nuclei come significant changes in the hydrodynamics of core collapse and bounce. We discuss these as well as the ramifications for the post-bounce evolution in core collapse supernovae.Comment: Accepted by PRL, 5 pages, 2 figure

Pastoralists do plan! Community-led land use planning in the pastoral areas of Ethiopia

This paper consolidates a set of case studies which document how pastoralists plan land and resource use in pastoral and agro-pastoral areas of Ethiopia. These case studies are drawn from the regional states of Afar, Somali, Southern Nations, Nationalities, and Peoples (SNNP), Oromia, and Gambella. They describe not only why, how, and when pastoralists plan, but also the management and governance structures that control planning processes and the later implementation of the plans. By doing this, the paper provides guidance on how best such planning processes can be supported, and how they can be integrated with and/or built on by other planning processes such as those led by government

The effect of 12C + 12C rate uncertainties on s-process yields

The slow neutron capture process in massive stars (the weak s-process) produces most of the s-only isotopes in the mass region 60 < A < 90. The nuclear reaction rates used in simulations of this process have a profound effect on the final s-process yields. We generated 1D stellar models of a 25 solar mass star varying the 12C + 12C rate by a factor of 10 and calculated full nucleosynthesis using the post-processing code PPN. Increasing or decreasing the rate by a factor of 10 affects the convective history and nucleosynthesis, and consequently the final yields.Comment: Conference proceedings for the Nuclear Physics in Astrophysics IV conference, 8-12 June 2009. 4 pages, 3 figures. Accepted for publication to the Journal of Physics: Conference Serie

Coronary vasomotor tone during static and dynamic exercise

Coronary vasomotion is an important determinant of myocardial perfusion in patients with angina pectoris, and it influences not only normal but also stenotic coronary arteries. The ability of a stenotic coronary artery to change its size is dependent on the presence of a normal musculo-elastic wall segment within the stenosis (i.e., eccentric stenosis). Coronary vasoconstriction of normal and stenotic coronary arteries has been reported by Brown and coworkers (Circulation 1984; 70: 18-24) during isometric exercise. The effect of dynamic exericse on coronary vasomotion was evaluated in one group of 13 patients with ischaemia-like symptoms and normal coronary arteries (group 1) and in a second group of 12 patients with coronary artery disease with exercise-induced angina pectoris (group 2). Luminal area of a normal and a stenotic vessel segment was determined by biplane quantitative coronary arteriography at rest, during supine bicycle exercise and 5 min after administration of 1·6 mg sublingual nitroglycerin. Coronary sinus blood flow was measured in group 1 at rest and after 0·5 mg kg−1 intravenous dipyridamole using coronary sinus thermodilution. Coronary flow reserve was calculated from coronary sinus flow after dipyridamole divided by coronary sinus flow at rest. In group 1, coronary vasodilation of the large (i.e., proximal) and the small (i.e., distal) coronary arteries was observed during exercise in seven patients (subgroup A). However, in the remaining six patients (subgroup B) coronary vasoconstriction of the small arteries (−24%, P<0·001) was found during exercise, whereas the large vessels showed coronary vasodilation (+26%, P<0·001). Coronary flow reserve was significantly (P<0·05) larger in subgroup A (mean 2·5) than in subgroup B (mean 1·2) with exercise-induced vasoconstriction of the small epicardial arteries. In group 2 vasodilation of the normal (+23%, P<0·001) and vasoconstriction of the stenotic coronary arteries (−29, P<0·001) was found during supine bicycle exercise. Administration of sublingual nitroglycerin at the end of the exercise test was accompanied by coronary vasodilation of both normal (+40%, P<0·001 vs rest) and stenotic (+12%, NS vs rest) vessel segments. It is concluded that isometric exercise is associated with reflex coronary vasoconstriction of the normal and stenotic vessel segments due to enhanced sympathetic stimulation. Dynamic exercise in patients with ischaemia-like symptoms and normal coronary arteries is accompanied by an abnormal dilatory response of the small coronary arteries in a subgroup of patients with reduced coronary flow reserve. Dynamic exercise in patients with coronary artery disease is, however, associated with coronary vasodilation of the normal and coronary vasoconstriction of the stenotic vessel segments. The nature of this exercise-induced vasoconstriction of stenotic coronary arteries is not clear, but might be related to endothelial dysfunction with an insufficient production of the endothelium-derived relaxing factor during exercis

Developmental exposure to lead (Pb) alters the expression of the human tau gene and its products in a transgenic animal model

Tauopathies are a class of neurodegenerative diseases associated with the pathological aggregation of the tau protein in the human brain. The best known of these illnesses is Alzheimer’s disease (AD); a disease where the microtubule associated protein tau (MAPT) becomes hyperphosphorylated (lowering its binding affinity to microtubules) and aggregates within neurons in the form of neurofibrillary tangles (NFTs). In this paper we examine whether environmental factors play a significant role in tau pathogenesis. Our studies were conducted in a double mutant mouse model that expressed the human tau gene and lacked the gene for murine tau. The human tau mouse model was tested for the transgene’s ability to respond to an environmental toxicant. Pups were developmentally exposed to lead (Pb) from postnatal day (PND) 1-20 with 0.2% Pb acetate. Mice were then sacrificed at PND 20, 30, 40 and 60. Protein and mRNA levels for tau and CDK5 as well as tau phosphorylation at Ser396 were determined. In addition, the potential role of miRNA in tau expression was investigated by measuring levels of miR-34c, a miRNA that targets the mRNA for human tau, at PND20 and 50. The expression of the human tau transgene was altered by developmental exposure to Pb. This exposure also altered the expression of miR-34c. Our findings are the first of their kind to test the responsiveness of the human tau gene to an environmental toxicant and to examine an epigenetic mechanism that may be involved in the regulation of this gene’s expression

X-ray Evidence of the Common Envelope Phase of V471 Tauri

Chandra Low Energy Transmission Grating Spectrograph observations of the pre-cataclysmic binary V471 Tau have been used to estimate the C/N abundance ratio of the K dwarf component for the first time. While the white dwarf component dominates the spectrum longward of 50 AA, at shorter wavelengths the observed X-ray emission is entirely due to coronal emission from the K dwarf. The H-like resonance lines of C and N yield an estimate of their logarithmic abundance ratio relative to the Sun of [C/N]=-0.38+/-0.15 - half of the currently accepted solar value. We interpret this result as the first clear observational evidence for the presumed common envelope phase of this system, during which the surface of the K dwarf was contaminated by CN-cycle processed material dredged up into the red giant envelope. We use the measured C/N ratio to deduce that 0.015-0.04 Msun was accreted by the K dwarf while engulfed, and show that this is consistent with a recent tentative detection of 13C in the K dwarf photosphere, and with the measured Li abundance in the scenario where the red giant companion was Li-rich during the common envelope phase.Comment: 6 pages, 2 figures, ApJL accepte