100 research outputs found
Fault imaging enhancement in Taranaki Basin, New Zealand and rock physics and inversion based reservoir characterization in the Central Gulf Coast region of Texas
Fault imaging technique and reservoir characterization based on rock physics analysis and pre-stack inversion has been widely used hydrocarbon exploration. For the fault imaging technique, the ant tracking has been widely used in fault interpretation. However, the reliability of the results is highly dependent on appropriately choosing a signal processing method and volume attributes. In our study area, which lies in the southern Taranaki Basin, we applied Graphic Equalizer as the processing tool and the Chaos attribute before running the ant tracking algorithm. Results show that the procedure provides a better result and can map both the major and minor faults more efficiently than the conventional fault interpretation procedure. For the reservoir characterization study, we use the Lower Wilcox strata which has been proven to be a good quality reservoir along the Central Gulf Coast of Texas. While the complexity of its sedimentary environment makes it hard to locate the isolated productive sand accurately. We carry out the rock physics analyses to provide a better understanding of the reservoir properties. Bulk density, P-wave velocity, and elastic moduli are extracted from four wells for analyzing the depth and temperature effects on compaction. A combination of three effective medium models is used for cement volume diagnostics. For the further reservoir characterization, we conduct the pre-stack seismic inversion with seven wells constrained. Our inversion results show a successful delineation of the reservoir using the Vp/Vs and S-Impedance values --Abstract, page iv
A scheme to fix multiple solutions in amplitude analyses
Decays of unstable heavy particles usually involve the coherent sum of
several amplitudes, like in a multiple slit experiment. Dedicated amplitude
analysis techniques have been widely used to resolve these amplitudes for
better understanding of the underlying dynamics. For special cases, where two
spin-1/2 particles and two (pseudo-)scalar particles are present in the
process, multiple equivalent solutions are found due to intrinsic symmetries in
the summed probability density function. In this paper, the problem of multiple
solutions is discussed and a scheme to overcome this problem is proposed by
fixing some free parameters. Toys are generated to validate the strategy. A new
approach to align helicities of initial- and final-state particles in different
decay chains is also introduced.Comment: 17 pages, 2 figure
Tunable photochemical deposition of silver nanostructures on layered ferroelectric CuInPS6
2D layered ferroelectric materials such as CuInPS6 (CIPS) are promising
candidates for novel and high-performance photocatalysts, owning to their
ultrathin layer thickness, strong interlayer coupling, and intrinsic
spontaneous polarization, while how to control the photocatalytic activity in
layered CIPS remains unexplored. In this work, we report for the first time the
photocatalytic activity of ferroelectric CIPS for the chemical deposition of
silver nanostructures (AgNSs). The results show that the shape and spatial
distribution of AgNSs on CIPS are tunable by controlling layer thickness,
environmental temperature, and light wavelength. The ferroelectric polarization
in CIPS plays a critical role in tunable AgNS photodeposition, as evidenced by
layer thickness and temperature dependence experiments. We further reveal that
AgNS photodeposition process starts from the active site creation, selective
nanoparticle nucleation/aggregation, to the continuous film formation.
Moreover, AgNS/CIPS heterostructures prepared by photodeposition exhibit
excellent resistance switching behavior and good surface enhancement Raman
Scattering activity. Our findings provide new insight into the photocatalytic
activity of layered ferroelectrics and offer a new material platform for
advanced functional device applications in smart memristors and enhanced
chemical sensors.Comment: 18 pages, 5 figure
Orthogonal Subspace Learning for Language Model Continual Learning
Benefiting from massive corpora and advanced hardware, large language models
(LLMs) exhibit remarkable capabilities in language understanding and
generation. However, their performance degrades in scenarios where multiple
tasks are encountered sequentially, also known as catastrophic forgetting. In
this paper, we propose orthogonal low-rank adaptation (O-LoRA), a simple and
efficient approach for continual learning in language models, effectively
mitigating catastrophic forgetting while learning new tasks. Specifically,
O-LoRA learns tasks in different (low-rank) vector subspaces that are kept
orthogonal to each other in order to minimize interference. Our method induces
only marginal additional parameter costs and requires no user data storage for
replay. Experimental results on continual learning benchmarks show that our
method outperforms state-of-the-art methods. Furthermore, compared to previous
approaches, our method excels in preserving the generalization ability of LLMs
on unseen tasks.Comment: EMNLP 2023 finding
TRACE: A Comprehensive Benchmark for Continual Learning in Large Language Models
Aligned large language models (LLMs) demonstrate exceptional capabilities in
task-solving, following instructions, and ensuring safety. However, the
continual learning aspect of these aligned LLMs has been largely overlooked.
Existing continual learning benchmarks lack sufficient challenge for leading
aligned LLMs, owing to both their simplicity and the models' potential exposure
during instruction tuning. In this paper, we introduce TRACE, a novel benchmark
designed to evaluate continual learning in LLMs. TRACE consists of 8 distinct
datasets spanning challenging tasks including domain-specific tasks,
multilingual capabilities, code generation, and mathematical reasoning. All
datasets are standardized into a unified format, allowing for effortless
automatic evaluation of LLMs. Our experiments show that after training on
TRACE, aligned LLMs exhibit significant declines in both general ability and
instruction-following capabilities. For example, the accuracy of llama2-chat
13B on gsm8k dataset declined precipitously from 28.8\% to 2\% after training
on our datasets. This highlights the challenge of finding a suitable tradeoff
between achieving performance on specific tasks while preserving the original
prowess of LLMs. Empirical findings suggest that tasks inherently equipped with
reasoning paths contribute significantly to preserving certain capabilities of
LLMs against potential declines. Motivated by this, we introduce the
Reasoning-augmented Continual Learning (RCL) approach. RCL integrates
task-specific cues with meta-rationales, effectively reducing catastrophic
forgetting in LLMs while expediting convergence on novel tasks
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KMT2A promotes melanoma cell growth by targeting hTERT signaling pathway.
Melanoma is an aggressive cutaneous malignancy, illuminating the exact mechanisms and finding novel therapeutic targets are urgently needed. In this study, we identified KMT2A as a potential target, which promoted the growth of human melanoma cells. KMT2A knockdown significantly inhibited cell viability and cell migration and induced apoptosis, whereas KMT2A overexpression effectively promoted cell proliferation in various melanoma cell lines. Further study showed that KMT2A regulated melanoma cell growth by targeting the hTERT-dependent signal pathway. Knockdown of KMT2A markedly inhibited the promoter activity and expression of hTERT, and hTERT overexpression rescued the viability inhibition caused by KMT2A knockdown. Moreover, KMT2A knockdown suppressed tumorsphere formation and the expression of cancer stem cell markers, which was also reversed by hTERT overexpression. In addition, the results from a xenograft mouse model confirmed that KMT2A promoted melanoma growth via hTERT signaling. Finally, analyses of clinical samples demonstrated that the expression of KMT2A and hTERT were positively correlated in melanoma tumor tissues, and KMT2A high expression predicted poor prognosis in melanoma patients. Collectively, our results indicate that KMT2A promotes melanoma growth by activating the hTERT signaling, suggesting that the KMT2A/hTERT signaling pathway may be a potential therapeutic target for melanoma
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