The Flan Collection: Designing Data and Methods for Effective Instruction Tuning

We study the design decisions of publicly available instruction tuning methods, and break down the development of Flan 2022 (Chung et al., 2022). Through careful ablation studies on the Flan Collection of tasks and methods, we tease apart the effect of design decisions which enable Flan-T5 to outperform prior work by 3-17%+ across evaluation settings. We find task balancing and enrichment techniques are overlooked but critical to effective instruction tuning, and in particular, training with mixed prompt settings (zero-shot, few-shot, and chain-of-thought) actually yields stronger (2%+) performance in all settings. In further experiments, we show Flan-T5 requires less finetuning to converge higher and faster than T5 on single downstream tasks, motivating instruction-tuned models as more computationally-efficient starting checkpoints for new tasks. Finally, to accelerate research on instruction tuning, we make the Flan 2022 collection of datasets, templates, and methods publicly available at https://github.com/google-research/FLAN/tree/main/flan/v2

Harmonic Sums and Mellin Transforms up to two-loop Order

A systematic study is performed on the finite harmonic sums up to level four. These sums form the general basis for the Mellin transforms of all individual functions $f_i(x)$ of the momentum fraction $x$ emerging in the quantities of massless QED and QCD up to two--loop order, as the unpolarized and polarized splitting functions, coefficient functions, and hard scattering cross sections for space and time-like momentum transfer. The finite harmonic sums are calculated explicitly in the linear representation. Algebraic relations connecting these sums are derived to obtain representations based on a reduced set of basic functions. The Mellin transforms of all the corresponding Nielsen functions are calculated.Comment: 44 pages Latex, contract number adde

Application of the bacteriophage Mu-driven system for the integration/amplification of target genes in the chromosomes of engineered Gram-negative bacteria—mini review

The advantages of phage Mu transposition-based systems for the chromosomal editing of plasmid-less strains are reviewed. The cis and trans requirements for Mu phage-mediated transposition, which include the L/R ends of the Mu DNA, the transposition factors MuA and MuB, and the cis/trans functioning of the E element as an enhancer, are presented. Mini-Mu(LR)/(LER) units are Mu derivatives that lack most of the Mu genes but contain the L/R ends or a properly arranged E element in cis to the L/R ends. The dual-component system, which consists of an integrative plasmid with a mini-Mu and an easily eliminated helper plasmid encoding inducible transposition factors, is described in detail as a tool for the integration/amplification of recombinant DNAs. This chromosomal editing method is based on replicative transposition through the formation of a cointegrate that can be resolved in a recombination-dependent manner. (E-plus)- or (E-minus)-helpers that differ in the presence of the trans-acting E element are used to achieve the proper mini-Mu transposition intensity. The systems that have been developed for the construction of stably maintained mini-Mu multi-integrant strains of Escherichia coli and Methylophilus methylotrophus are described. A novel integration/amplification/fixation strategy is proposed for consecutive independent replicative transpositions of different mini-Mu(LER) units with “excisable” E elements in methylotrophic cells

\u3cem\u3eCampylobacter jejuni\u3c/em\u3e Response to Human Mucin MUC2: Modulation of colonization and pathogenicity determinants

Campylobacter jejuni is the main cause of bacterial acute gastroenteritis worldwide. In its colonization of the host intestinal tract, it encounters secreted mucins in the mucus layer and surface mucins in the epithelial cells. Mucins are complex glycoproteins that comprise the major component of mucus and give mucus its viscous consistency. MUC2 is the most abundant secreted mucin in the human intestine; it is a major chemoattractant for C. Jejuni, and the bacterium binds to it. There are no studies on the transcriptional response of the bacterium to this mucin. Here, cell-culture techniques and quantitative RT-PCR were used to characterize in vitro the effects of MUC2 on C. jejuni growth and the changes in expression of 20 C. jejuni genes related to various functions

Hepatocellular carcinoma: Prevalence and molecular pathogenesis of \u3cem\u3eHelicobacter\u3c/em\u3e spp

Helicobacter pylori infection is one of the most common chronic bacterial infections in humans. The association of other Helicobacter spp. with extragastric diseases in animals is well established, and a role of these bacteria in human liver disease is becoming clearer. Several case–control studies have reported possible associations of Helicobacter spp. with various liver diseases, including hepatocellular carcinoma, which is the fifth most common type of carcinoma among men worldwide, and the eighth most common among women. Thus, it is important to understand molecular mechanisms that may lead to hepatotoxicity or hepatocellular dysfunction in which Helicobacter spp. may play a role in inducing malignant transformation of liver cells

Simulation dataset of thermal and epithermal neutron self-shielding correction factors for 186W(n,γ)187W reaction rate experiments using tungsten foil targets

In the experiments of neutron interaction with research samples, the incident neutron energy spectrum, distribution inside the irradiating sample volume, is affected by the unexpected neutron self-shielding effects. The nature of these effects is due to the formation and thickness of the irradiating sample, which significantly causes neutron self-absorption and multiple scattering inside the sample volume. The datasets presented in this article showed the thermal (Gth) and epithermal (Gepi) neutron self-shielding correction factors for the 186W(n,γ)187W neutron capture reaction rate in irradiating tungsten (W) foil samples with different thicknesses. The simulations were performed for three models of surface neutron source's geometries and relative orientations of the irradiating foil samples of isotropic cylinder surface neutron source with foil sample along to the center line, isotropic cylinder neutron source with foil sample flat to the center line, and isotropic spherical neutron source with foil sample placed at the center point. The range of sample thicknesses was from 10 µm to 2.5 mm. The uncertainties for each data point are also reported in the data table, making it more convenient for reuse in related experiments or evaluations

Photo thermal radiometry method development and application for nuclear technologies

International audienceIn the search for new materials for nuclear industry and reliable nuclear safe technologies, much attention is given to methods for non-destructive remote testing and control of materials in severe environment of nuclear installations. Photo thermal radiometry, as one of these possible methods, is under development in the CEA (French Atomic Energy Commission). In our studies, it was used with repetition rate laser heating of a sample by either a pulsed (100 ns-1 ms, 1-10000 Hz) [1, 2] or a sinusoidal modulated laser power (1 Hz - 1 MHz) [2,3] followed by measurements of the thermal radiation emitted by the sample under study. Thermal radiation time-dependence or phase shifts between the laser power and the thermal radiation measured at different modulated frequencies (lock-in radiometry) were then compared with those obtained with a model of laser heating to characterize some sample properties (thermal diffusivity, thickness, layer adhesion, under-surface defects and their changes in time). Samples from European TOKAMAKS (graphite or carbon fibre composite protective tiles with 1 - 100 µm deposits) and nuclear installations (metal pieces, Zircaloy cladding, micrometric oxide layers or PVD thin films, 3D-printed metal objects) were tested and characterized with the home-made experimental setups and the developed analytical (3D+t) models of laser heating [4-6]. The numerical simulation of laser heating was used to fit the calculated thermal radiation or phase shifts with the experimental ones by adjusting the material properties. This method of characterization was validated with a set of etalon samples. The applied methods will be presented along with the obtained results. The possible ways to improve the method to widen the scope of its application in the nuclear industry will be discussed as well.1.A. Semerok, S. V. Fomichev, J.-M. Weulersse, F. Brygo and P.-Y. Thro, Journal of Applied Physics 101, 084916 (2007)2.A. Semerok, F. Jaubert, S.V. Fomichev, P.-Y.Thro, X .Courtois, C. Grisolia, Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment A693, 98 (2012)3.N. Horny, M. Chirtoc, A. Fleming, G. Hamaoui and H. Ban, Applied Physics Letters 109, 033103 (2016)4.A. Semerok, S.V. Fomichev, F. Jaubert, C. Grisolia, Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment A738, 25 (2014)5.S. Pham Tu Quoc, G. Cheymol, A. Semerok, Review of Scientific Instruments 85, 054903 (2014)6.A. Semerok, S. Pham Tu Quoc, G. Cheymol, C. Gallou, H. Maskrot and G. Moutiers, European Journal of Physics, Nuclear Sciences & Technology 2, 20 (2016) doi: https://doi.org/10.1051/epjn/201601

Campylobacter jejuni response to human mucin MUC2: modulation of colonization and pathogenicity determinants

Campylobacter jejuni is the main cause of bacterial acute gastroenteritis worldwide. In its colonization of the host intestinal tract, it encounters secreted mucins in the mucus layer and surface mucins in the epithelial cells. Mucins are complex glycoproteins that comprise the major component of mucus and give mucus its viscous consistency. MUC2 is the most abundant secreted mucin in the human intestine; it is a major chemoattractant for C. jejuni, and the bacterium binds to it. There are no studies on the transcriptional response of the bacterium to this mucin. Here, cell-culture techniques and quantitative RT-PCR were used to characterize in vitro the effects of MUC2 on C. jejuni growth and the changes in expression of 20 C. jejuni genes related to various functions. The genes encoding cytolethal distending toxin protein (cdtABC), vacuolating cytotoxin (vacB), C. jejuni lipoprotein (jlpA), Campylobacter invasion antigen (ciaB), the multidrug efflux system (cmeAB), putative mucin-degrading enzymes (cj1344c, cj0843c, cj0256 and cj1055c), flagellin A (flaA) and putative rod-shape-determining proteins (mreB and mreC) were upregulated, whereas those encoding Campylobacter adhesion fibronectin-binding protein (cadF) and sialic acid synthase (neuB1) were downregulated. These results showed that C. jejuni utilizes MUC2 as an environmental cue for the modulation of expression of genes with various functions including colonization and pathogenicity