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1.
Nat Commun ; 15(1): 2768, 2024 Mar 30.
Article in English | MEDLINE | ID: mdl-38553456

ABSTRACT

Contextual embeddings, derived from deep language models (DLMs), provide a continuous vectorial representation of language. This embedding space differs fundamentally from the symbolic representations posited by traditional psycholinguistics. We hypothesize that language areas in the human brain, similar to DLMs, rely on a continuous embedding space to represent language. To test this hypothesis, we densely record the neural activity patterns in the inferior frontal gyrus (IFG) of three participants using dense intracranial arrays while they listened to a 30-minute podcast. From these fine-grained spatiotemporal neural recordings, we derive a continuous vectorial representation for each word (i.e., a brain embedding) in each patient. Using stringent zero-shot mapping we demonstrate that brain embeddings in the IFG and the DLM contextual embedding space have common geometric patterns. The common geometric patterns allow us to predict the brain embedding in IFG of a given left-out word based solely on its geometrical relationship to other non-overlapping words in the podcast. Furthermore, we show that contextual embeddings capture the geometry of IFG embeddings better than static word embeddings. The continuous brain embedding space exposes a vector-based neural code for natural language processing in the human brain.


Subject(s)
Brain , Language , Humans , Prefrontal Cortex , Natural Language Processing
2.
Adv Mater ; 36(5): e2304910, 2024 Feb.
Article in English | MEDLINE | ID: mdl-37926960

ABSTRACT

The adaptive control of sunlight through photochromic smart windows could have a huge impact on the energy efficiency and daylight comfort in buildings. However, the fabrication of inorganic nanoparticle and polymer composite photochromic films with a high contrast ratio and high transparency/low haze remains a challenge. Here, a solution method is presented for the in situ growth of copper-doped tungsten trioxide nanoparticles in polymethyl methacrylate, which allows a low-cost preparation of photochromic films with a high luminous transparency (luminous transmittance Tlum = 91%) and scalability (30 × 350 cm2 ). High modulation of visible light (ΔTlum = 73%) and solar heat (modulation of solar transmittance ΔTsol = 73%, modulation of solar heat gain coefficient ΔSHGC = 0.5) of the film improves the indoor daylight comfort and energy efficiency. Simulation results show that low-e windows with the photochromic film applied can greatly enhance the energy efficiency and daylight comfort. This photochromic film presents an attractive strategy for achieving more energy-efficient buildings and carbon neutrality to combat global climate change.

3.
Biol Conserv ; 256: 109013, 2021 Apr.
Article in English | MEDLINE | ID: mdl-34580543

ABSTRACT

High traffic volume is one of the main contributors to wildlife-vehicle collision (WVC) and wildlife mortality on roads. Government shelter-in-place (SIP) orders have been used to help mitigate the spread of COVID-19, resulting in unprecedented reductions in global traffic volumes. Using traffic and collision data from four US states (California, Idaho, Maine, and Washington), we investigated changes in total WVC, following the state and local SIP orders. From mid-March to mid-April 2020, these orders have resulted in up to 71%, 63%, 73%, and 72% reduction in driving, as measured by vehicle miles traveled (VMT), in CA, ID, ME, and WA respectively. The daily WVC rates from the 4 weeks prior to SIP orders going into effect, to the 4 weeks after, declined 34%, with 21, 36, 44, and 33% declines for CA, ID, ME, and WA, respectively. For mountain lions (Puma concolor) in CA, there was a 58% decline in mortality during the traffic reduction. The changes in WVC from 1 month pre-SIP orders to 1 month post-order only occurred in 2020 and not 2015, 2016, 2017, 2018, or 2019, suggesting that the reductions were associated with the reductions in traffic. The measured declines in WVC reversed in ME and WA during May, June and July 2020, paralleling reversals in traffic volumes. A 34% reduction in WVC would potentially equate to 10s of millions fewer vertebrates killed on US roadways during one month of traffic reduction, representing an unintentional conservation action unprecedented in modern times.

4.
Physiol Meas ; 25(3): 699-708, 2004 Jun.
Article in English | MEDLINE | ID: mdl-15253121

ABSTRACT

Medical diagnostics and clinical practice rely extensively on test and measurement instrumentation. It is therefore of paramount importance that test and measurement instrumentation provides reliable data of sufficient stability, within appropriate limits of accuracy. At the same time the intended purpose of a particular measuring instrument has to be taken into account. The essential problem of every measuring instrument is that it measures and indicates basically what appears at the input of the measuring instrument, which might be significantly different from the real condition of a measurand. Namely, it is assumed that a measurand is stable, repeatable, and relatively unsusceptible to environmental influences. All these requirements are difficult to assure in a biological system and especially difficult in medical practice. Technology could easily provide high-resolution measurements, but due to natural instability of a measurand and various influential parameters the measurement uncertainty is inevitable. Sometimes even gross measurement errors are introduced. To achieve the expected accuracy for intended purpose is therefore much more demanding than merely relying on manufacturers' specifications. This paper describes and analyses the mentioned dilemmas in the case of widely used infrared ear thermometers, with their benefits and limitations, as well as with regard to the European technical regulation in the field of medical devices.


Subject(s)
Ear/blood supply , Ear/physiology , Equipment Failure Analysis/methods , Equipment and Supplies/standards , Spectrophotometry, Infrared/instrumentation , Technology Assessment, Biomedical/methods , Thermometers/standards , Equipment Failure Analysis/standards , European Union , Guideline Adherence , Guidelines as Topic , Reference Standards , Reproducibility of Results , Sensitivity and Specificity , Spectrophotometry, Infrared/standards , Technology Assessment, Biomedical/standards
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