Describing the practice of anticipating students’ mathematics of secondary mathematics teachers : a multi-case study

Teachers’ ability to elicit and use evidence of student thinking during instruction is critical in high-quality mathematics instruction. The practice of anticipating students’ mathematics supports teachers in noticing and being prepared to respond to student thinking during in-the-moment instruction. To date, most research on anticipating has involved teachers in formal professional learning contexts such as university coursework or professional development programs and has focused on identifying and describing teachers’ anticipations. However, few studies have investigated anticipating in the context of professional practice or how it is enacted by teachers with a variety of experiences. This study examines three secondary mathematics teachers’ practice of anticipating students’ mathematics. Using a multi-case study design, it examines the ways in which these three teachers anticipate, the resources they draw upon, the purposes they have for engaging in the practice and highlights similarities and differences in their enactments. Findings indicate that when anticipating the ways students will engage with cognitively demanding mathematics tasks, teachers first consider their instructional contexts, including their curricular programs, academic standards, and the focal mathematical ideas for units of instruction. To varying degrees, they develop records of mathematical activity students might demonstrate and conjectures about ways students might think mathematically when engaging with these tasks. Beyond these similarities, teachers in this study drew upon different domains of knowledge and enacted the practice for different purposes. The results of this study have implications for mathematics teacher educators working to support mathematics teachers learning to anticipate as well as researchers investigating instructional practices in context

Metabolomics demonstrates divergent responses of two Eucalyptus species to water stress

Past studies of water stress in Eucalyptus spp. generally highlighted the role of fewer than five “important” metabolites, whereas recent metabolomic studies on other genera have shown tens of compounds are affected. There are currently no metabolite profiling data for responses of stress-tolerant species to water stress. We used GC–MS metabolite profiling to examine the response of leaf metabolites to a long (2 month) and severe (Ψpredawn < −2 MPa) water stress in two species of the perennial tree genus Eucalyptus (the mesic Eucalyptus pauciflora and the semi-arid Eucalyptus dumosa). Polar metabolites in leaves were analysed by GC–MS and inorganic ions by capillary electrophoresis. Pressure–volume curves and metabolite measurements showed that water stress led to more negative osmotic potential and increased total osmotically active solutes in leaves of both species. Water stress affected around 30–40% of measured metabolites in E. dumosa and 10–15% in E. pauciflora. There were many metabolites that were affected in E. dumosa but not E. pauciflora, and some that had opposite responses in the two species. For example, in E. dumosa there were increases in five acyclic sugar alcohols and four low-abundance carbohydrates that were unaffected by water stress in E. pauciflora. Re-watering increased osmotic potential and decreased total osmotically active solutes in E. pauciflora, whereas in E. dumosa re-watering led to further decreases in osmotic potential and increases in total osmotically active solutes. This experiment has added several extra dimensions to previous targeted analyses of water stress responses in Eucalyptus, and highlights that even species that are closely related (e.g. congeners) may respond differently to water stress and re-waterin

Unprocessed Viral DNA Could Be the Primary Target of the HIV-1 Integrase Inhibitor Raltegravir

Integration of HIV DNA into host chromosome requires a 3′-processing (3′-P) and a strand transfer (ST) reactions catalyzed by virus integrase (IN). Raltegravir (RAL), commonly used in AIDS therapy, belongs to the family of IN ST inhibitors (INSTIs) acting on IN-viral DNA complexes (intasomes). However, studies show that RAL fails to bind IN alone, but nothing has been reported on the behaviour of RAL toward free viral DNA. Here, we assessed whether free viral DNA could be a primary target for RAL, assuming that the DNA molecule is a receptor for a huge number of pharmacological agents. Optical spectroscopy, molecular dynamics and free energy calculations, showed that RAL is a tight binder of both processed and unprocessed LTR (long terminal repeat) ends. Complex formation involved mainly van der Waals forces and was enthalpy driven. Dissociation constants (Kds) revealed that RAL affinity for unbound LTRs was stronger than for bound LTRs. Moreover, Kd value for binding of RAL to LTRs and IC50 value (half concentration for inhibition) were in same range, suggesting that RAL binding to DNA and ST inhibition are correlated events. Accommodation of RAL into terminal base-pairs of unprocessed LTR is facilitated by an extensive end fraying that lowers the RAL binding energy barrier. The RAL binding entails a weak damping of fraying and correlatively of 3′-P inhibition. Noteworthy, present calculated RAL structures bound to free viral DNA resemble those found in RAL-intasome crystals, especially concerning the contacts between the fluorobenzyl group and the conserved 5′C4pA33′ step. We propose that RAL inhibits IN, in binding first unprocessed DNA. Similarly to anticancer drug poisons acting on topoisomerases, its interaction with DNA does not alter the cut, but blocks the subsequent joining reaction. We also speculate that INSTIs having viral DNA rather IN as main target could induce less resistance

Emergence of vancomycin resistant Staphylococcus aureus (VRSA) from a tertiary care hospital from northern part of India

BACKGROUND: Glycopeptides such as vancomycin are frequently the antibiotics of choice for the treatment of infections caused by methicillin resistant Staphylococcus aureus (MRSA). For the last 7 years incidence of vancomycin intermediate S. aureus and vancomycin resistant S. aureus (VISA and VRSA respectively) has been increasing in various parts of the world. The present study was carried out to find out the presence of VISA and VRSA in the northern part of India. METHODS: A total 1681 staphylococcal isolates consisting of 783 S. aureus and 898 coagulase negative staphylococci (CoNS) were isolated from different clinical specimens from various outpatient departments and wards. All S. aureus and 93 CoNS were subjected to MIC testing (against vancomycin, teicolplanin and oxacillin); Brain Heart Infusion (BHI) vancomycin screen agar test; disc diffusion testing, and PCR for mecA, vanA and vanB genes detection. RESULTS: Out of 783 S. aureus two S. aureus strains were found to be vancomycin and teicoplanin resistant (one strain with MIC 32 μg/ml and the other strain with MIC 64 μg/ml); six strains of S. aureus have shown to be vancomycin intermediate (two strains with MIC 16 μg/ml and four strains with MIC 8 μg/ml); and two strains with teicoplanin intermediate (MIC 16 μg/ml). One CoNS strain was resistant to vancomycin and teicoplanin (MIC 32 μg/ml), and two CoNS strains were intermediate to vancomycin and teicoplanin (MIC 16 μg/ml). All VRSA, VISA and vancomycin resistant CoNS had shown growth on BHI vancomycin screen agar (vancomycin 6 μg/ml) and were mecA PCR positive. None of these isolates have demonstrated vanA/vanB gene by PCR. CONCLUSION: The present study reveals for the first time emergence of VISA/VRSA from this part of world and indicates the magnitude of antibiotic resistance in and around the study area. The major cause of this may be unawareness and indiscriminate use of broad-spectrum antibiotics

Jet energy measurement with the ATLAS detector in proton-proton collisions at root s=7 TeV

The jet energy scale and its systematic uncertainty are determined for jets measured with the ATLAS detector at the LHC in proton-proton collision data at a centre-of-mass energy of √s = 7TeV corresponding to an integrated luminosity of 38 pb-1. Jets are reconstructed with the anti-kt algorithm with distance parameters R=0. 4 or R=0. 6. Jet energy and angle corrections are determined from Monte Carlo simulations to calibrate jets with transverse momenta pT≥20 GeV and pseudorapidities {pipe}η{pipe}<4. 5. The jet energy systematic uncertainty is estimated using the single isolated hadron response measured in situ and in test-beams, exploiting the transverse momentum balance between central and forward jets in events with dijet topologies and studying systematic variations in Monte Carlo simulations. The jet energy uncertainty is less than 2. 5 % in the central calorimeter region ({pipe}η{pipe}<0. 8) for jets with 60≤pT<800 GeV, and is maximally 14 % for pT<30 GeV in the most forward region 3. 2≤{pipe}η{pipe}<4. 5. The jet energy is validated for jet transverse momenta up to 1 TeV to the level of a few percent using several in situ techniques by comparing a well-known reference such as the recoiling photon pT, the sum of the transverse momenta of tracks associated to the jet, or a system of low-pT jets recoiling against a high-pT jet. More sophisticated jet calibration schemes are presented based on calorimeter cell energy density weighting or hadronic properties of jets, aiming for an improved jet energy resolution and a reduced flavour dependence of the jet response. The systematic uncertainty of the jet energy determined from a combination of in situ techniques is consistent with the one derived from single hadron response measurements over a wide kinematic range. The nominal corrections and uncertainties are derived for isolated jets in an inclusive sample of high-pT jets. Special cases such as event topologies with close-by jets, or selections of samples with an enhanced content of jets originating from light quarks, heavy quarks or gluons are also discussed and the corresponding uncertainties are determined. © 2013 CERN for the benefit of the ATLAS collaboration

Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

The inclusive and dijet production cross-sections have been measured for jets containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The measurements use data corresponding to an integrated luminosity of 34 pb^-1. The b-jets are identified using either a lifetime-based method, where secondary decay vertices of b-hadrons in jets are reconstructed using information from the tracking detectors, or a muon-based method where the presence of a muon is used to identify semileptonic decays of b-hadrons inside jets. The inclusive b-jet cross-section is measured as a function of transverse momentum in the range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet cross-section is measured as a function of the dijet invariant mass in the range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets and the angular variable chi in two dijet mass regions. The results are compared with next-to-leading-order QCD predictions. Good agreement is observed between the measured cross-sections and the predictions obtained using POWHEG + Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet cross-section. However, it does not reproduce the measured inclusive cross-section well, particularly for central b-jets with large transverse momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final version published in European Physical Journal

Television viewing, food preferences, and food habits among children: A prospective epidemiological study

<p>Abstract</p> <p>Background</p> <p>Obesity has increased since the early 1980s, and despite numerous attempts, effective strategies to counter this worldwide epidemic are lacking. Food preferences are established early in life and are difficult to change later. There is therefore a need to identify factors that influence the development of food preferences. Our aim was therefore, to investigate cross-sectional and prospective associations between TV viewing habits and food preferences and habits, respectively. We hypothesized that more TV viewing was associated with less healthy concomitant and future food preferences and food habits.</p> <p>Methods</p> <p>Data are from the Danish part of European Youth Heart Study (EYHS) I and II, a prospective cohort study conducted among 8-10-year-old and 14-16-year-old Danes in 1997-98. Six years later 2003-04 the 8-10-year-olds were followed up at age 14-16 years, and a new group of 8-10-year olds were included. Data were analysed using mixed linear regression analysis. Cross-sectional analyses included 697 8-10-year-olds and 495 14-16-year-olds. Prospective analyses included 232 pupils with complete data at baseline and follow-up. Associations between TV viewing habits and the sum of healthy food preferences (ΣHFP), and the sum of healthy food habits (ΣHFH), respectively, were examined.</p> <p>Results</p> <p>Inverse cross-sectional associations between TV viewing (h/day) and both ΣHFP and ΣHFH were present for both the 8-10-year-old and the 14-16-year-old boys and girls. The frequency of meals in front of the TV (times/week) was also inversely associated with ΣHFP among 8-10-year-old boys, and with ΣHFH in all sex- and age groups. Among girls, baseline TV viewing (h/day) was directly associated with adverse development in the ΣHFP during follow-up. The concomitant 6-year changes in ΣHFH and TV viewing (h/day) were inversely associated in boys.</p> <p>Conclusions</p> <p>Long time spent on TV viewing, and possibly to a lesser degree, frequent consumption of meals during TV viewing, seem to be associated with generally having unhealthy food preferences and food habits among school-aged children. These associations, however, were not generally persistent after 6 years of follow-up.</p

Selective Reduction of Post-Selection CD8 Thymocyte Proliferation in IL-15Rα Deficient Mice

Peripheral CD8+ T cells are defective in both IL-15 and IL-15Rα knock-out (KO) mice; however, whether IL-15/IL-15Rα deficiency has a similar effect on CD8 single-positive (SP) thymocytes remains unclear. In this study, we investigated whether the absence of IL-15 transpresentation in IL-15Rα KO mice results in a defect in thymic CD8 single positive (SP) TCRhi thymocytes. Comparison of CD8SP TCRhi thymocytes from IL-15Rα KO mice with their wild type (WT) counterparts by flow cytometry showed a significant reduction in the percentage of CD69− CD8SP TCRhi thymocytes, which represent thymic premigrants. In addition, analysis of in vivo 5-bromo-2-deoxyuridine (BrdU) incorporation demonstrated that premigrant expansion of CD8SP TCRhi thymocytes was reduced in IL-15Rα KO mice. The presence of IL-15 transpresentation-dependent expansion in CD8SP TCRhi thymocytes was assessed by culturing total thymocytes in IL-15Rα-Fc fusion protein-pre-bound plates that were pre-incubated with IL-15 to mimic IL-15 transpresentation in vitro. The results demonstrated that CD8SP thymocytes selectively outgrew other thymic subsets. The contribution of the newly divided CD8SP thymocytes to the peripheral CD8+ T cell pool was examined using double labeling with intrathymically injected FITC and intravenously injected BrdU. A marked decrease in FITC+ BrdU+ CD8+ T cells was observed in the IL-15Rα KO lymph nodes. Through these experiments, we identified an IL-15 transpresentation-dependent proliferation process selective for the mature CD8SP premigrant subpopulation. Importantly, this process may contribute to the maintenance of the normal peripheral CD8+ T cell pool

Photosynthesis by six portuguese maize cultivars during drought stress and recovery

Photosynthesis, chlorophyll fluorescence and leaf water parameters were measured in six Portuguese maize (Zea mays L.) cultivars during and following a period of drought stress. The leaf relative water content (RWC) responded differently among cultivars but, except for cultivar PB369, recovered close to initial values after watering was restored. Photosynthetic rate and stomatal conductance decreased with drought but more slowly in cultivars PB269 and PB260 than in cultivars AD3R, PB64, PB304 and PB369. Water use efficiency (WUE) decreased during the water stress treatment although with cultivar PB260 the decrease was marked only when the RWC fell below 40%. Recovery of WUE was seen with all cultivars except PB369. The maximum quantum efficiency of photosystem II, the photochemical quenching coefficient, the electron transport rate in PSII and the estimated functional plastoquinone pool tended to decrease with drought, while the non -photochemical quenching coefficient increased. The parameters estimated from chlorophyll fluorescence did not recover in PB369, during re - watering. The results show that PB260 and PB269 were the most tolerant and PB369 was the least tolerant cultivars to water stress. The variation found amongst the cultivars tested suggests the existence of valuable genetic resources for crop improvement in relation to drought tolerance