Promotion with and without learning : effects on student enrollment and dropout behavior

Many educators and policymakers have argued for lenient grade promotion policy - even automatic promotion - in developing country settings where grade retention rates are high. The argument assumes that grade retention discourages persistence or continuation in school and that the promotion of children with lower achievement does not hamper their ability or their peers'ability to perform at the next level. Alternatively, promoting students into grades for which they are not prepared may lead to early dropout behavior. This study shows that in a sample of schools from the Northwest Frontier Province of Pakistan, students are promoted primarily on the basis of merit. An econometric decomposition of promotion decisions into a component that is based on merit indicators (attendance and achievement in mathematics and language) and another that is uncorrelated with those indicators allows a test of whether parental decisions to keep their child in school is influenced by merit-based or non-merit-based promotions. Results suggest that the enrollment decision is significantly influenced by whether learning has taken place, and that grade promotion that is uncorrelated with merit has a negligible impact on school continuation.Tertiary Education,Education For All,Secondary Education,Primary Education,Teaching and Learning

HEAVY METAL-RESISTANT RHIZOBACTERIA FROM GOLD MINE IN PONGKOR INDONESIA AND COPPER MINE IN MARINDUQUE PHILIPPINES

The purposes of the study was to isolate, to characterize, and to identify rhizobacteria from plant rhizosphere growing in gold and copper mine. The isolation of rhizobacteria used N-free semisolid agar media, TSA, and SLP plus heavy metals (HMs), namely Pb, Cd, and or Cu. Isolated rhizobacteria were subsequently characterized for resistance to higher level of Pb, Cd, Cu in SLP media. Cultural and morphological characterization of rhizobacteria were conducted for cell morphology, motility, Gram staining, and biofilm formation. The rhizobacteria identification used sequence analysis of the 16S RNA gene fragments. The results showed that the majority of rhizobacterial from Cu mine site (66.7% of 21 isolates) were resistant to Cu (72150 ppm) while the majority of rhizobacteria from gold mine site (77.8% of 18 isolates) were sensitive to 72 ppm Cu. Majority of Cu in the soil was insoluble as granules attaching to gravel so that rhizobacteria of Cu mine site have been exposed and adapted to available Cu. This fact, explaining that the rhizobacteria’s MIC value was lower than the total Cu level in the soil. Three HMs-resistant rhizobacter (PbSM 2.1, MGR 334, and CuNFbM 4.1) formed biofilms, which was as one of the resistance mechanism to HMs. This research informed that HM contaminated-soil is better source for obtaining HM resistant rhizobacteria than HM uncontaminated-soil. The use four isolation media produce rhizobacteria which was more diverse than rhizobacteria from each isolation medium. Further characterization needs to be done to obtain HM resistant-rhizobacteria which can be used as biofertilizers and phytoremediation agent.Penelitian ini bertujuan mengisolasi, mengkarakterisasi, dan mengidentifikasi rhizobacteria dari rhizosfer tanaman yang tumbuh di situs tambang tembaga dan emas. Isolasi rhizobakter menggunakan media agar semisolid bebas N, TSA, dan SLP yang mengandung logam berat Pb, Cd, dan atau Cu. Rhizobakter hasil isolasi dikarakterisasi resistensinya terhadap Pb, Cd, Cu pada level lebih tinggi menggunakan agar SLP. Karakterisasi morfologi dan kultur yang dilakukan meliputi morfologi sel, motilitas, pewarnaan Gram, dan produksi biofilm. Identifikasi rhizobakter dengan sekuensing fragmen gen 16S RNA. Hasil penelitian menunjukkan sebagian besar rhizobakter dari situs tambang Cu (66.7% dari 21 isolat) resisten terhadap Cu (72-150 ppm) sementara sebagian besar rhizobakter dari lokasi tambang emas (77.8% dari 18 isolat) sensitif terhadap 72 ppm Cu. Sebagian besar logam Cu di dalam tanah situs tambang tembaga tidak larut dalam bentuk granul terikat batuan kerikil. Tampaknya rhizobakter dari situs tambang Cu terpapar dan beradaptasi dengan Cu yang tersedia di dalam tanah sehingga menjelaskan mengapa nilai MICnya terhadap Cu lebih rendah dari level Cu total di dalam tanah. Tiga rhizobakter resisten logam (PbSM 2.1, MGR 334, dan CuNFbM 4.1) menunjukkan kemampuan membentuk biofilm, yang diduga sebagai salah satu mekanisme resistensinya terhadap logam berat. Hasil penelitian ini juga menginformasikan bahwa tanah terkontaminasi logam berat merupakan sumber rhizobakter resisten logam yang lebih baik daripada tanah tidak terkontaminasi logam berat. Penggunaan keempat media dalam isolasi menghasilkan rhizobacteria dengan karakteristik yang lebih beragam daripada penggunaan media tunggal. Karakterisasi lebih lanjut perlu dilakukan untuk mendapatkan rhizobacteria resisten logam berat yang dapat digunakan sebagai inokulan pupuk hayati dan agen fitoremediasi

Promotion with and without Learning: Effects on Student Enrollment and Dropout Behavior

Automatic promotion policy presumes that grade retention discourages continuation in school and that the lenient promotion of students with poor performance does not hamper their ability to do well in the next grade. However, promoting students into grades for which they are not prepared may backfire, leading to early dropouts. An econometric decomposition of promotion decisions into a component that is based on merit (attendance and achievement in tests) and another component that is uncorrelated with those indicators allows a test of whether parental decisions to keep their child in school is influenced by merit-based or nonmerit-based promotions. Results suggest that the enrollment decision is significantly influenced by whether learning has taken place. The effect of grade promotions uncorrelated with merit on persistence in school is only 20 to 33 percent as large as the effect attributed to merit-based promotion

Promotion with and without learning: effects on student enrollment and dropout behavior

Many educators and policymakers have argued for lenient grade promotion policy -- even automatic promotion -- in developing country settings where grade retention rates are high. The argument assumes that grade retention discourages persistence or continuation in school and that the promotion of children with lower achievement does not hamper their ability or their peer\u27s ability to perform at the next level. Alternatively, promoting students into grades for which they are not prepared may lead to early dropout behavior. This study shows that in a sample of schools from the Northwest Frontier Province (NWFP) of Pakistan, students are promoted primarily on the basis of merit. An econometric decomposition of promotion decisions into a component that is based on merit indicators (attendance and achievement in mathematics and language) and another that is uncorrelated with those indicators allow a test of whether parental decisions to keep their child in school is influenced by merit-based or non-merit-based promotions. Results suggest that the enrollment decision is significantly influenced by whether learning has taken place, and that grade promotion that is uncorrelated with merit has a negligible impact on school continuation

Neutron polarisation analysis of Polymer: Fullerene blends for organic photovoltaics

The photogeneration process in polymer-fullerene organic solar cells relies strongly on the nanostructure and on the nano/picosecond dynamics occurring in these complex blends. Elastic and inelastic neutron scattering techniques are valuable tools with which to investigate those features in the appropriate time and space domains. In particular, quasi-elastic neutron scattering (QENS) connects useful structural and dynamical information by the measurement of dynamical incoherent (single particle) fluctuations in soft materials as a function of lengthscale. Extraction of these fluctuation rates can, however, be hampered by the presence of coherent contributions, originating from elastic scattering, and/or inelastic scattering modes which overlap in the space/time domain with the incoherent single-particle motions. As we have already seen in a previous study [1], this happens in poly(3-hexylthiophene) (P3HT) and [6,6]-Phenyl C61 butyric acid methyl ester (PCBM) solid blends, in which the coherent contribution arising from the PCBM crystalline phase seems to affect the interpretation of the polymer dynamics. Here, we utilise neutron polarisation analysis as an effective tool to separate coherent and incoherent contributions and make QENS data analysis of these blends more reliable

Low-Temperature Photoluminescence Spectroscopy of Solvent-Free PCBM Single-Crystals

PCBM ([6,6]-phenyl-C61-butyric acid methyl ester) is a highly soluble C60 derivative that is extensively used in organic solar cells, enabling power conversion efficiencies above 10%. Here we report, for the first time to the best of our knowledge, the photoluminescence of high-quality solvent-free PCBM crystals between room temperature and 4 K. Interestingly, the PL spectra of these crystals become increasingly structured as the temperature is lowered, with extremely well-resolved emission lines (and a minimum line width of ∼1.3 meV at 1.73 eV). We are able to account for such a structured emission by means of a vibronic coupling model including Franck–Condon, Jahn–Teller and Herzberg–Teller effects. Although optical transitions are not formally forbidden from the low-lying excited states of PCBM, the high symmetry of the electronically active fullerene core limits the intensity of the 0–0 transition, such that Herzberg–Teller transitions which borrow intensity from higher-lying states represent a large part of the observed spectrum. Our simulations suggest that the emissive state of PCBM can be considered as a mixture of the T1g and Hg excited states of C60 and hence that the Hg state plays a larger role in the relaxed excited state of PCBM than in that of C60

Tuning Fullerene Intercalation in a Poly (thiophene) derivative by Controlling the Polymer Degree of Self-Organisation

Controlling the nanoscale arrangement in polymer-fullerene organic solar cells is of paramount importance to boost the performance of such promising class of photovoltaic diodes. In this work, we use a pseudo-bilayer system made of poly(2,5-bis(3-hexadecylthiophen-2-yl)thieno[3,2-b]thiophene (PBTTT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), to acquire a more complete understanding of the diffusion and intercalation of the fullerene-derivative within the polymer layer. By exploiting morphological and structural characterisation techniques, we observe that if we increase the film solidification time the polymer develops a higher crystalline order, and, as a result, it does not allow fullerene molecules to intercalate between the polymer side-chains. Gaining insight into the detailed fullerene intercalation mechanism is important for the development of organic photovoltaic diodes (PVDs)

Student and teacher attendance: The role of shared goods in reducing absenteeism

A theoretical model is advanced that demonstrates that, if teacher and student attendance generate a shared good, then teacher and student attendance will be mutually reinforcing. Using data from the Northwest Frontier Province of Pakistan, empirical evidence supporting that proposition is advanced. Controlling for the endogeneity of teacher and student attendance, the most powerful factor raising teacher attendance is the attendance of the children in the school, and the most important factor influencing child attendance is the presence of the teacher. The results suggest that one important avenue to be explored in developing policies to reduce teacher absenteeism is to focus on raising the attendance of children