412 research outputs found
Speak, Memory: An Archaeology of Books Known to ChatGPT/GPT-4
In this work, we carry out a data archaeology to infer books that are known
to ChatGPT and GPT-4 using a name cloze membership inference query. We find
that OpenAI models have memorized a wide collection of copyrighted materials,
and that the degree of memorization is tied to the frequency with which
passages of those books appear on the web. The ability of these models to
memorize an unknown set of books complicates assessments of measurement
validity for cultural analytics by contaminating test data; we show that models
perform much better on memorized books than on non-memorized books for
downstream tasks. We argue that this supports a case for open models whose
training data is known.Comment: EMNLP 2023 camera-ready (16 pages, 4 figures
4-D Computational Modeling of Cardiac Outflow Tract Hemodynamics over Looping Developmental Stages in Chicken Embryos
Cardiogenesis is interdependent with blood flow within the embryonic system. Recently, a number of studies have begun to elucidate the effects of hemodynamic forces acting upon and within cells as the cardiovascular system begins to develop. Changes in flow are picked up by mechanosensors in endocardial cells exposed to wall shear stress (the tangential force exerted by blood flow) and by myocardial and mesenchymal cells exposed to cyclic strain (deformation). Mechanosensors stimulate a variety of mechanotransduction pathways which elicit functional cellular responses in order to coordinate the structural development of the heart and cardiovascular system. The looping stages of heart development are critical to normal cardiac morphogenesis and have previously been shown to be extremely sensitive to experimental perturbations in flow, with transient exposure to altered flow dynamics causing severe late stage cardiac defects in animal models. This paper seeks to expand on past research and to begin establishing a detailed baseline for normal hemodynamic conditions in the chick outflow tract during these critical looping stages. Specifically, we will use 4-D (3-D over time) optical coherence tomography to create in vivo geometries for computational fluid dynamics simulations of the cardiac cycle, enabling us to study in great detail 4-D velocity patterns and heterogeneous wall shear stress distributions on the outflow tract endocardium. This information will be useful in determining the normal variation of hemodynamic patterns as well as in mapping hemodynamics to developmental processes such as morphological changes and signaling events during and after the looping stages examined here
A new stress dilatometer and measurement of the thermal expansion under uniaxial stress of MnSn
We present a method for measuring thermal expansion under tunable uniaxial
stresses, and show measurements of the thermal expansion of MnSn, a room
temperature antiferromagnet that exhibits a spontaneous Hall effect, under
uniaxial stresses of up to 1.51 GPa compression. Measurement of thermal
expansion provides thermodynamic data about the nature of phase transitions,
and uniaxial stress provides a powerful tuning method that does not introduce
disorder. MnSn exhibits an anomaly in its thermal expansion near 270
K, associated with a first-order change in its magnetic structure. We show this
transition temperature is suppressed by 54.6 K by 1.51 GPa compression along
[0001]. We find the associated entropy change at the transition to be
0.1 J mol K and to vary only weakly with applied stress
Infection dynamics of two renal myxozoans in hatchery reared fry and juvenile Atlantic cod Gadus morhua L.
In order to study the infection dynamics of 2 renal myxozoans, Zschokkella hildae Auerbach, 1910 and Gadimyxa atlantica Køie, Karlsbakk and Nylund, 2007 in cultured Atlantic cod, Gadus morhua L. aged 3–19 months, a specific single-round PCR assay and a double-label in situ hybridization protocol were developed. The results demonstrated that the 2 myxozoans show spatial separation of their development with regard to spore formation inside the renal tubules versus the collecting ducts and ureters, as well as temporal separation with Z. hildae proliferating and developing spores only once the G. atlantica infection decreases, despite the presence of both myxozoans in the smallest fry studied. These results strongly suggest within-host competition of the 2 myxozoans with potential suppression of Z. hildae by G. atlantica until G. morhua acquires immunity against G. atlantica. The quantification of the G. atlantica infection inside the renal tubules before and after a 29-day experimental growth performance study using fry from hatcheries with differing filtration systems showed that the intensity of infection with G. atlantica seems to be controlled if prolonged exposure to the myxozoan transmission stages takes place from hatching onwards. Surprisingly, growth rates in the trial were inversely affected suggesting that G. atlantica does not negatively influence cod fry growth performance
Diffusive and ballistic current spin-polarization in magnetron-sputtered L1o-ordered epitaxial FePt
We report on the structural, magnetic, and electron transport properties of a
L1o-ordered epitaxial iron-platinum alloy layer fabricated by
magnetron-sputtering on a MgO(001) substrate. The film studied displayed a long
range chemical order parameter of S~0.90, and hence has a very strong
perpendicular magnetic anisotropy. In the diffusive electron transport regime,
for temperatures ranging from 2 K to 258 K, we found hysteresis in the
magnetoresistance mainly due to electron scattering from magnetic domain walls.
At 2 K, we observed an overall domain wall magnetoresistance of about 0.5 %. By
evaluating the spin current asymmetry alpha = sigma_up / sigma_down, we were
able to estimate the diffusive spin current polarization. At all temperatures
ranging from 2 K to 258 K, we found a diffusive spin current polarization of >
80%. To study the ballistic transport regime, we have performed point-contact
Andreev-reflection measurements at 4.2 K. We obtained a value for the ballistic
current spin polarization of ~42% (which compares very well with that of a
polycrystalline thin film of elemental Fe). We attribute the discrepancy to a
difference in the characteristic scattering times for oppositely spin-polarized
electrons, such scattering times influencing the diffusive but not the
ballistic current spin polarization.Comment: 22 pages, 13 figure
Genetic Connectivity and Diversity of a Protected, Habitat-Forming Species:Evidence Demonstrating the Need for Wider Environmental Protection and Integration of the Marine Protected Area Network
Funding Information: This work was largely funded by Heriot-Watt University (James Watt Scholarship) and NatureScot (formerly Scottish Natural Heritage). Additional funding was received from the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland) and their support is gratefully acknowledged. MASTS was funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions.Peer reviewedPublisher PD
Intermittent applied mechanical loading induces subchondral bone thickening that may be intensified locally by contiguous articular cartilage lesions
Objectives: Changes in subchondral bone (SCB) and cross-talk with articular cartilage (AC) have been linked to osteoarthritis (OA). Using micro-computed tomography (micro-CT) this study: (1) examines changes in SCB architecture in a non-invasive loading mouse model in which focal AC lesions are induced selectively in the lateral femur, and (2) determines any modifications in the contralateral knee, linked to changes in gait, which might complicate use of this limb as an internal control. Methods: Right knee joints of CBA mice were loaded: once with 2weeks of habitual use (n=7), for 2weeks (n=8) or for 5weeks (n=5). Both left (contralateral) and right (loaded) knees were micro-CT scanned and the SCB and trabecular bone analysed. Gait analysis was also performed. Results: These analyses showed a significant increase in SCB thickness in the lateral compartments in joints loaded for 5weeks, which was most marked in the lateral femur; the contralateral non-loaded knee also showed transient SCB thickening (loaded once and repetitively). Epiphyseal trabecular bone BV/TV and trabecular thickness were also increased in the lateral compartments after 5 weeks of loading, and in all joint compartments in the contralateral knee. Gait analysis showed that applied loading only affected gait in the contralateral himd-limb in all groups of mice from the second week after the first loading episode. Conclusions: These data indicate a spatial link between SCB thickening and AC lesions following mechanical trauma, and the clear limitations associated with the use of contralateral joints as controls in such OA models, and perhaps in OA diagnosis
Comparing Path Dependence and Spatial Targeting of Land Use in Implementing Climate Change Responses
Peer reviewedPublisher PD
Project-based learning - area of improving the quality of school
U traženju najboljih načina za ostvarivanje ciljeva nastave, jedno od mogućih didaktičkih rješenja pronalazimo u projektnoj nastavi. Ravitz i sur. (2012) opisuju projektnu nastavu kao koncept stvaranja uvjeta u kojima učenici mogu učiti složenija znanja i vještine koja su im nepohodna za život u 21. stoljeću. Ona predstavlja brojne izazove za učitelje i škole, a poteškoće na koje nailaze pri njezinoj implementaciji su brojne. Za učinkovito rješavanje problema implementacije projektne nastave u radu škole, neophodno je omogućiti učiteljima samovrednovanje nastavnog procesa. Samovrednovanje je proces koji sustavno prati, analizira i procjenjuje uspješnost rada kako bi se trajno unaprijedila kvaliteta i stvorilo poticajno radno okruženje. U ovom je radu prikazan primjer Školskog razvojnog plana, kao sastavnog dijela procesa samovrednovanja, kojim je projektna nastava definirana kao prioritetno područje unaprjeđenja rada škole i razvojnih ciljeva koji proizlaze iz njih.In finding the best ways to accomplish learning goals one of the possible didactic solutions would be project-based learning. Ravitz et al. (2012) describe project-based learning as a concept that involves creating conditions which would help students learn more complex knowledge and skills vital for the life in the 21st century. This concept holds many challenges for both teachers and schools, and many issues arise in its implementation. The effective solution for the implementation problems of project-based learning in schools necessary involves self-evaluation of the teaching process. Self-evaluation is a process that systematically monitors, analyses and assesses the work performance in order to permanently achieve better quality and create a more productive working surroundings. This paper shows an example of a school development plan, as an integral part of the self-evaluation process, that defines the project-based learning as a priority area in improving the school processes and development goals which derive from them
- …