An Elementary Proof of Dodgson's Condensation Method for Calculating Determinants

In 1866, Charles Ludwidge Dodgson published a paper concerning a method for evaluating determinants called the condensation method. His paper documented a new method to calculate determinants that was based on Jacobi's Theorem. The condensation method is presented and proven here, and is demonstrated by a series of examples. The condensation method can be applied to a number of situations, including calculating eigenvalues, solving a system of linear equations, and even determining the different energy levels of a molecular system. The method is much more efficient than cofactor expansions, particularly for large matrices; for a 5 x 5 matrix, the condensation method requires about half as many calculations. Zeros appearing in the interior of a matrix can cause problems, but a way around the issue can usually be found. Overall, Dodgson's condensation method is an interesting and simple way to find determinants. This paper presents an elementary proof of Dodgson's method.Comment: 7 pages, no figure

Peningkatan Keterampilan Berbicara Pada Materi Ungkapan Tolong Dan Terima Kasih Muatan Pelajaran Bahasa Indonesia Melalui Video Animasi Bagi Siswa Kelas Ia SD Negeri 1 Tanjung Kecamatan Purwokerto Selatan Kabupaten Banyumas Pada Semester I Tahun Pelajaran 2020/2021.

Penelitian ini bertujuan untuk meningkatkan keterampilan berbicara pada materi ungkapan tolong dan terima kasih melalui video animasi pada muatan pelajaran Bahasa Indonesia bagi peserta didik kelas IA SD Negeri  1 Tanjung Kecamatan Puwokerto Selatan Kabupaten Banyumas. Jenis penelitian ini adalah Penelitian Tindakan Kelas (PTK) yang dilaksanakan dalam tiga siklus.Penelitian Tindakan Kelas ini secara daring mengingat kondisi Covid 19 yang terjadi saat ini sehingga tidak dimungkinkan pembelajaran tatap muka. Pelaksaan pembelajaran dilakukan menggunakan platform Google Meet dan Zoom Meeting dengan presentasi menggunakan media power point yang didalamnya terdapat video animasi ungkapan tolong dan terima kasih yang bertujuan untuk meingkatkan keterampilan berbicara pada peserta didik kelas 1A SD N 1 Tanjung Kecamatan Purwokerto Selatan Kabupaten Banyumas.Keterampilan berbicara merupakan keterampilan kebahasaan yang sangat penting. Menurut Brown dan Yule (dalam Santosa, 2009:6.34), berbicara dapat diartikan sebagai kemampuan mengucapkan bunyi-bunyi bahasa untuk mengekspresikan atau menyampaikan pikiran, gagasan atau perasaan secara lisan. Berbicara sering dianggap sebagai alat manusia yang paling penting bagi kontrol sosial, karena berbicara merupakan suatu bentuk perilaku manusia yang memanfaatkan faktor-faktor fisik, psikologis, neurologist, dan linguistik secara luas.Dari penelitian tindakan kelas ini diperoleh penilaian unjuk kerja keterampilan berbicara subjek penelitian dari kondisi awal dengan rata – rata nilai 58, siklus I memperoleh rata – rata nilai 60.2, siklus II memperoleh nilai rata-rata 76,6 dan di siklus III memperoleh nilai rata-rata 86,5. Dengan demikian dari kondisi awal ke kondisi akhir, rata – rata nilai keterampilan berbicara ungkapan tolong dan terima kasih subjek penelitian mengalami peningkatan 28,5 poin. Dengan ketuntasan di siklus III mencapai 100%. Sehingga dapat disimpulkan bahwa melalui penggunaan  media video animasi dapat meningkatkan keterampilan berbicara peserta didik pada materi ungkapan  tolong dan terima kasih dengan muatan pelajaran Bahasa Indonesia siswa kelas IA SD Negeri 1 Tanjung Kecamatan Purwokerto Selatan Kabupaten Banyumas Tahun ajaran 2020/2021.Kata Kunci  : Video animasi, Tolong, Terima kasih

Summary of Donor Subcommittee Discussions on CGIAR Impact Study

Decisions on the scope and budget of the CGIAR impact study by a donor subcommittee, which also selected a study director and members for an advisory committee. Agenda document, CGIAR meeting October-November 1983

Rapid Determination of Activation Energies for Gas-Phase Protein Unfolding and Dissociation in a Q-IM-ToF Mass Spectrometer

Ion mobility-mass spectrometry has emerged as a powerful tool for interrogating a wide variety of chemical systems. Collision-induced unfolding (CIU), typically performed in time-of-flight instruments, has been utilized to obtain valuable qualitative insight into protein structure and illuminate subtle differences between related species. CIU experiments can be performed relatively quickly, but unfolding energy information obtained from them has not yet been interpreted quantitatively. While several methods can determine quantitative dissociation energetics for small molecules, clusters, and peptides, these methods have rarely been applied to proteins, and never to study unfolding. Here, we present a method to rapidly determine activation energies for protein unfolding and dissociation, built on a model for energy deposition during collisional activation. The method is validated by comparing activation energies for dissociation of three complexes with those obtained using Blackbody Infrared Radiative Dissociation (BIRD); values from the two methods are in agreement. Several protein monomers were unfolded using CIU, including multiple charge states of both cations and anions, and activation energies determined. ΔH‡ and ΔS‡ values are found to be correlated, leading to ΔG‡ values that lie within a narrow range (~70–80 kJ/mol) and vary more with charge state than with protein identity. ΔG‡ is anticorrelated with charge density, highlighting the key role of Coulombic repulsion in gas-phase unfolding. Measured ΔG‡ values are similar to those computed for proton transfer within small peptides, suggesting that proton transfer is the rate-limiting step in gas-phase unfolding and providing evidence of a link between the Mobile Proton model and CIU

Experimental and Theoretical Investigation of Overall Energy Deposition in Surface-Induced Unfolding of Protein Ions

Recent advances in native mass spectrometry have enabled its use to probe the structure of and interactions within biomolecular complexes. Surface-induced dissociation, in which inter- and intramolecular interactions are disrupted following an energetic ion-surface collision, is a method that can directly interrogate the topology of protein complexes. However, a quantitative relationship between the ion kinetic energy at the moment of surface collision and the internal energy deposited into the ion has not yet been established for proteins. The factors affecting energy deposition in surface-induced unfolding (SIU) of protein monomers were investigated and a calibration relating laboratory-frame kinetic energy to internal energy developed. Protein monomers were unfolded by SIU and by collision-induced unfolding (CIU). CIU and SIU cause proteins to undergo the same unfolding transitions at different values of laboratory-frame kinetic energy. There is a strong correlation between the SIU and CIU energies, demonstrating that SIU, like CIU, can largely be understood as a thermal process. The change in internal energy in CIU was modeled using a Monte Carlo approach and theory. Computed values of the overall efficiency were found to be approximately 25% and used to rescale the CIU energy axis and relate nominal SIU energies to internal energy. The energy deposition efficiency in SIU increases with mass and kinetic energy from a low of -20% to a high of -68%, indicating that the effective mass of the surface increases along with the mass of the ion. The effect of ion structure on energy deposition was probed using multiple stages of ion activation. Energy deposition in SIU strongly depends on structure, decreasing as the protein is elongated, due to decreased effective protein-surface collisional cross section and increased transfer to rotational modes

Value-for-money discourse : risks and opportunities for R4D

French version available in IDRC Digital Library: Optimisation des ressources : risques et possibilités pour la recherche au service du développementThis brief examines the value-for-money (VfM) discourse, including VfM in international development and challenges of articulating VfM in research for development (R4D). It provides four practical measures R4D can use to articulate VfM, and provides some questions that can help in assessing VfM in R4D. The term (VfM) is now common in both private and public sectors, and is becoming synonymous with accountability and transparency. An example of VfM assessment – as process, could be based on a portfolio of projects; this could encompass risks, recognizing that partial success and even failure, are vital parts of the learning process

Evaluating Volatile Organic Compound Emissions from Cross-Laminated Timber Bonded with a Soy-Based Adhesive

Volatile organic compound (VOC) emissions from indoor sources are large determinants of the indoor air quality (IAQ) and occupant health. Cross-laminated timber (CLT) is a panelized engineered wood product often left exposed as an interior surface finish. As a certified structural building product, CLT is currently exempt from meeting VOC emission limits for composite wood products and confirming emissions through California Department of Public Health (CDPH) Standard Method testing. In this study, small chamber testing was conducted to evaluate VOC emissions from three laboratory-produced CLT samples: One bonded with a new soy-based cold-set adhesive; a second bonded with a commercially available polyurethane (PUR) adhesive; and the third assembled without adhesive using dowels. A fourth commercially-produced eight-month-old sample bonded with melamine formaldehyde (MF) adhesive was also tested. All four samples were produced with Douglas-fir. The test results for the three laboratory-produced samples demonstrated VOC emissions compliance with the reference standard. The commercially-produced and aged CLT sample bonded with MF adhesive did not meet the acceptance criterion for formaldehyde of ≤9.0 µg/m3. The estimated indoor air concentration of formaldehyde in an office with the MF sample was 54.4 µg/m3; the results for the soy, PUR, and dowel samples were all at or below 2.5 µg/m3

Increasing Collisional Activation of Protein Complexes Using Smaller Aperture Source Sampling Cones on a Synapt Q-IM-TOF Instrument with a Stepwave Source

Quadrupole-ion mobility-time-of-flight (Q-IM-TOF) mass spectrometers have revolutionized investigation of native biomolecular complexes. High pressures in the sources of these instruments aid transmission of protein complexes through damping of kinetic energy by collisional cooling. Since adducts are removed through collisional heating (declustering), excessive collisional cooling can prevent removal of non-specific adducts from protein ions, leading to inaccurate mass measurements, broad mass spectral peaks, and obfuscation of ligand binding. We show that reducing the source pressure using smaller aperture source sampling cones (SC) in a Waters Synapt G2-Si instrument increases protein ion heating by decreasing collisional cooling, providing a simple way to enhance removal of adducted salts from soluble proteins (GroEL 14-mer) and detergents from a transmembrane protein complex (heptameric Staphylococcus aureus α-hemolysin, αHL). These experiments are supported by ion heating and cooling simulations which demonstrate reduced collisional cooling at lower source pressures. Using these easily-swapped sample cones of different apertures is a facile approach to reproducibly extend the range of activation in Synapt-type instruments