13 research outputs found
How Language Model Hallucinations Can Snowball
A major risk of using language models in practical applications is their
tendency to hallucinate incorrect statements. Hallucinations are often
attributed to knowledge gaps in LMs, but we hypothesize that in some cases,
when justifying previously generated hallucinations, LMs output false claims
that they can separately recognize as incorrect. We construct three
question-answering datasets where ChatGPT and GPT-4 often state an incorrect
answer and offer an explanation with at least one incorrect claim. Crucially,
we find that ChatGPT and GPT-4 can identify 67% and 87% of their own mistakes,
respectively. We refer to this phenomenon as hallucination snowballing: an LM
over-commits to early mistakes, leading to more mistakes that it otherwise
would not make
Measuring and Narrowing the Compositionality Gap in Language Models
We investigate the ability of language models to perform compositional
reasoning tasks where the overall solution depends on correctly composing the
answers to sub-problems. We measure how often models can correctly answer all
sub-problems but not generate the overall solution, a ratio we call the
compositionality gap. We evaluate this ratio by asking multi-hop questions with
answers that require composing multiple facts unlikely to have been observed
together during pretraining. In the GPT-3 family of models, as model size
increases we show that the single-hop question answering performance improves
faster than the multi-hop performance does, therefore the compositionality gap
does not decrease. This surprising result suggests that while more powerful
models memorize and recall more factual knowledge, they show no corresponding
improvement in their ability to perform this kind of compositional reasoning.
We then demonstrate how elicitive prompting (such as chain of thought)
narrows the compositionality gap by reasoning explicitly instead of implicitly.
We present a new method, self-ask, that further improves on chain of thought.
In our method, the model explicitly asks itself (and then answers) follow-up
questions before answering the initial question. We finally show that
self-ask's structured prompting lets us easily plug in a search engine to
answer the follow-up questions, which additionally improves accuracy
A new mixed type crack propagation criterion in shale reservoirs
Hydraulic fracturing is a mainstream technology for unconventional oil and gas reservoirs development all over the world. How to use this technology to achieve high-level oil and gas resource extraction and how to form complex fracture networks as hydrocarbon transportation channels in tight reservoirs, which depends to a large extent on the interaction between hydraulic and pre-existing cracks. For hydraulic fracturing of fractured reservoirs, the impact of natural fractures, perforation direction, stress disturbances, faults and other influencing factors will produce a mixed â… &â…¡ mode hydraulic fracture. To forecast whether hydraulic fractures cross pre-existing fractures, according to elastic mechanics and fracture mechanics, a stress state of cracks under the combination of tensile (â… ) and shear (â…¡) is presented. A simple mixed-mode â… &â…¡ hydraulic fracture's crossing judgment criterion is established, and the propagation of hydraulic fractures after encountering natural fractures is analyzed. The results show that for a given approaching angle there exists a certain range of stress ratio when crossing occurs. Under high approaching angle and large stress ratio, it is likely that hydraulic cracks will go directly through pre-existing cracks. The reinitiated angle is always controlled within the range of approximately 30° among the main direction of penetration
Advances in Conjugated Polymer Lasers
This paper provides a review of advances in conjugated polymer lasers. High photoluminescence efficiencies and large stimulated emission cross-sections coupled with wavelength tunability and low-cost manufacturing processes make conjugated polymers ideal laser gain materials. In recent years, conjugated polymer lasers have become an attractive research direction in the field of organic lasers and numerous breakthroughs based on conjugated polymer lasers have been made in the last decade. This paper summarizes the recent progress of the subject of laser processes employing conjugated polymers, with a focus on the photoluminescence principle and excitation radiation mechanism of conjugated polymers. Furthermore, the effect of conjugated polymer structures on the laser threshold is discussed. The most common polymer laser materials are also introduced in detail. Apart from photo-pumped conjugated polymer lasers, a direction for the future development of electro-pumped conjugated polymer lasers is proposed
Biomimetic Human Serum Albumin Nanoparticle for Efficiently Targeting Therapy to Metastatic Breast Cancers
Triple-negative
breast cancers (TNBCs), devoid of hormone receptors and human epidermal
growth-factor receptor-2/Neu expression, bring about poor prognosis
and induce a high rate of systematic metastases. The ineffectiveness
of current therapies on TNBCs could be attributed to the lack of efficient
targeted therapy. Paclitaxel (PTX) is considered one of first-line
chemotherapeutics for TNBC treatment but, due to its low aqueous solubility
and nonspecific accumulation, results in poor antitumor efficacy.
The present study is aimed at enhancing the chemotherapeutic potency
of PTX by improving the stability and targeting efficiency of PTX-loaded
nanoparticulate drug carriers. Here, PTX was incorporated in nontoxic
and endogenous material, human serum albumin (HSA), via an innovative
disulfide reduction method to construct HSA-based PTX nanoparticle
(HSA-PTX NP) to not only realize redox-responsive drug release but
also improve in vivo stability. Besides, W peptide was selected as
a target ligand to be conjugated with HSA-PTX NP for endowing active
targeting ability. The resulting Wpep-HSA-PTX NP possessed a spherical
structure (118 nm), 9.87% drug-loading content, and 86.3% entrapment
efficiency. An in vitro drug release test showed that PTX release
from Wpep-HSA-PTX NP was of a redox-responsive manner. Furthermore,
cellular uptake of Wpep-HSA-PTX NP was significantly enhanced, exhibiting
the improved antiproliferation and antitube formation effects of PTX
in vitro. In comparison with those commercial formulations and conventional
HSA NP, Wpep-HSA-PTX NP exhibited better pharmacokinetic behaviors
and tumor homing characteristics. The antitumor efficacy of Wpep-HSA-PTX
NP was further confirmed by the strong pro-apoptotic effect and reduced
tumor burden. In a word, this evidence highlighted the proof of concept
for Wpep-HSA NP as a promising conqueror to the ineffectiveness of
TNBC therapy