43 research outputs found
THE NATIONAL AND REGIONAL IMPORTANCE OF WHOLESALE PRODUCE MARKETS
The results of a three-year study to establish baseline estimates of the importance of wholesale produce markets (WPM) are reported. It is estimated that a third of all produce marketed in the United States and Canada goes through WPM. These facilities tend to be most important in larger urban areas. Gate and unloading fees commonly charged at WPM may place them at a competitive disadvantage relative to off-market sites.Agribusiness,
Feed-Forward Latent Domain Adaptation
We study a new highly-practical problem setting that enables resource-constrained edge devices to adapt a pretrained model to their local data distributions. Recognizing that device’s data are likely to come from multiple latent domains that include a mixture of unlabelled domain-relevant and domain-irrelevant examples, we focus on the comparatively under-studied problem of latent domain adaptation. Considering limitations of edge devices, we aim to only use a pre-trained model and adapt it in a feed-forward way, without using back-propagation and without access to the source data. Modelling these realistic constraints bring us to the novel and practically important problem setting of feedforward latent domain adaptation. Our solution is to metalearn a network capable of embedding the mixed-relevance target dataset and dynamically adapting inference for target examples using cross-attention. The resulting framework leads to consistent improvements over strong ERM baselines. We also show that our framework sometimes even improves on the upper bound of domain-supervised adaptation, where only domain-relevant instances are provided for adaptation. This suggests that human annotated domain labels may not always be optimal, and raises the possibility of doing better through automated instance selection
Feed-Forward Source-Free Latent Domain Adaptation via Cross-Attention
We study the highly practical but comparatively under-studied problem of
latent-domain adaptation, where a source model should be adapted to a target
dataset that contains a mixture of unlabelled domain-relevant and
domain-irrelevant examples. Furthermore, motivated by the requirements for data
privacy and the need for embedded and resource-constrained devices of all kinds
to adapt to local data distributions, we focus on the setting of feed-forward
source-free domain adaptation, where adaptation should not require access to
the source dataset, and also be back propagation-free. Our solution is to
meta-learn a network capable of embedding the mixed-relevance target dataset
and dynamically adapting inference for target examples using cross-attention.
The resulting framework leads to consistent improvement on strong ERM
baselines. We also show that our framework sometimes even improves on the upper
bound of domain-supervised adaptation, where only domain-relevant instances are
provided for adaptation. This suggests that human annotated domain labels may
not always be optimal, and raises the possibility of doing better through
automated instance selection.Comment: Shorter version accepted at the First Workshop of Pre-training:
Perspectives, Pitfalls, and Paths Forward at ICML 202
Pushing the Limits of Simple Pipelines for Few-Shot Learning: External Data and Fine-Tuning Make a Difference
Few-shot learning (FSL) is an important and topical problem in computer
vision that has motivated extensive research into numerous methods spanning
from sophisticated meta-learning methods to simple transfer learning baselines.
We seek to push the limits of a simple-but-effective pipeline for more
realistic and practical settings of few-shot image classification. To this end,
we explore few-shot learning from the perspective of neural network
architecture, as well as a three stage pipeline of network updates under
different data supplies, where unsupervised external data is considered for
pre-training, base categories are used to simulate few-shot tasks for
meta-training, and the scarcely labelled data of an novel task is taken for
fine-tuning. We investigate questions such as: (1) How pre-training on external
data benefits FSL? (2) How state-of-the-art transformer architectures can be
exploited? and (3) How fine-tuning mitigates domain shift? Ultimately, we show
that a simple transformer-based pipeline yields surprisingly good performance
on standard benchmarks such as Mini-ImageNet, CIFAR-FS, CDFSL and Meta-Dataset.
Our code and demo are available at https://hushell.github.io/pmf.Comment: Accepted by CVPR202
Rapamycin-coated expanded polytetrafluoroethylene bypass grafts exhibit decreased anastomotic neointimal hyperplasia in a porcine model
ObjectiveWe tested the hypothesis that rapamycin coated onto, and eluted from, expanded polytetrafluoroethylene (ePTFE) grafts would diminish neointimal hyperplasia in a porcine model.MethodsRapamycin (also called sirolimus) was coated onto the luminal surface of 6-mm-internal-diameter thin-walled ePTFE grafts by using an adhesive polymer that allows timed release of the drug. An adhesive polymer that allows timed release of rapamycin from ePTFE was developed with commercially available chemicals and applied on 6-mm ePTFE grafts. Graft integrity was characterized by scanning electron microscopy, and rapamycin levels were quantified by using high-performance liquid chromatography. Twenty-two mongrel pigs were randomized into three groups: untreated ePTFE (n = 6), adhesive-only coated ePTFE (n = 6), or adhesive- and rapamycin-coated ePTFE (n = 10). End-to-side unilateral aortoiliac bypasses were performed by using 6-mm-internal-diameter ePTFE grafts and standardized anastomotic lengths. Unilateral end-to-side aortoiliac ePTFE grafts (6-mm internal diameter) were inserted by using polypropylene sutures, 6-0 proximally and 7-0 distally; all anastomoses were 12 mm long. All animals received aspirin (325 mg orally) daily. All animals were given oral aspirin (325 mg) daily beginning on the day before surgery. At 28 days, the animals were killed, and the grafts were explanted in continuity with the adjacent aortic cuff and the outflow iliac artery. Variables compared between groups included graft patency, distal anastomotic length and cross-sectional narrowing, and intimal thickness at the arterial-graft junction indexed to the adjacent graft thickness. Microscopic analysis was performed with hematoxylin and eosin and Masson trichrome stains on paraffin sections. A pathologist blinded to experimental groups graded sections for collagen deposition, neointima formation, inflammatory cellular infiltrates, medial necrosis, and aneurysmal degeneration.ResultsAll animals survived until they were killed without clinical evidence of limb ischemia or graft infection. Preplanned t tests in the context of one-way analysis of variance showed no difference in outcome measures between the untreated ePTFE and adhesive-only coated ePTFE groups; therefore, they were combined in further comparisons with the adhesive- and rapamycin-coated ePTFE group. The Rapamycine eluting expanded polytetrafluoroethylene group had longer anastomoses (85.6% vs 60.6% of the initial anastomotic length maintained; P < .0001) and less cross-sectional narrowing in the outflow graft (16.2% vs 28.5%; P = .0007) when compared with the other two groups by using two-tailed Student t tests. There was no evidence of medial necrosis or aneurysmal degeneration. All patent grafts had complete endothelialization on hematoxylin and eosin sections. Rapamycin was detectable and quantifiable in the arterial wall at 28 days after implantation.ConclusionsRapamycin can be coated onto and eluted from ePTFE by using a nonionic polymer and a simple coating technique. At 4 weeks after implantation, the rapamycin-eluting ePTFE grafts demonstrate gross, pathologic, and morphometric features of diminished neointimal hyperplasia when compared with non–drug-eluting ePTFE. Four weeks after implantation in a porcine model, rapamycin-eluting ePTFE grafts demonstrated gross, pathologic, and morphometric features of diminished neointimal hyperplasia when compared with untreated and adhesive-only coated ePTFE grafts.Clinical RelevanceRapamycin-eluting ePTFE grafts decrease neointimal hyperplasia in a porcine model. Further studies are needed to evaluate whether patency will be improved. Rapamycin-eluting ePTFE grafts may allow the use of prosthetic grafts in situations in which autologous vein is unavailable and in which neointimal hyperplasia is pronounced, such as in small-diameter (<6-mm) vessels typical of infrapopliteal interventions
Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures
Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo
THE NATIONAL AND REGIONAL IMPORTANCE OF WHOLESALE PRODUCE MARKETS
The results of a three-year study to establish baseline estimates of the importance of wholesale produce markets (WPM) are reported. It is estimated that a third of all produce marketed in the United States and Canada goes through WPM. These facilities tend to be most important in larger urban areas. Gate and unloading fees commonly charged at WPM may place them at a competitive disadvantage relative to off-market sites
THE CHANGING MARKETS FOR FRESH FRUITS AND VEGETABLES IN THE UNITED STATES: 1978 TO 1987
Crop Production/Industries, Industrial Organization,