Occam learning

We discuss probabilistic neural network models for unsupervised learning where the distribution of the hidden layer is fixed. We argue that learning machines with this architecture enjoy a number of desirable properties. For example, the model can be chosen as a simple and interpretable one, it does not need to be over-parametrised and training is argued to be efficient in a thermodynamic sense. When hidden units are binary variables, these models have a natural interpretation in terms of features. We show that the featureless state corresponds to a state of maximal ignorance about the features and that learning the first feature depends on non-Gaussian statistical properties of the data. We suggest that the distribution of hidden variables should be chosen according to the principle of maximal relevance. We introduce the Hierarchical Feature Model (HFM) as an example of a model that satisfies this principle, and that encodes a neutral a priori organisation of the feature space. We present extensive numerical experiments in order i) to test that the internal representation of learning machines can indeed be independent of the data with which they are trained and ii) that only a finite number of features are needed to describe a number of datasets.Comment: 31 pages, 10 figure

Superiority of GNN over NN in generalizing bandlimited functions

Graph Neural Network (GNN) with its ability to integrate graph information has been widely used for data analyses. However, the expressive power of GNN has only been studied for graph-level tasks but not for node-level tasks, such as node classification, where one tries to interpolate missing nodal labels from the observed ones. In this paper, we study the expressive power of GNN for the said classification task, which is in essence a function interpolation problem. Explicitly, we derive the number of weights and layers needed for a GNN to interpolate a band-limited function in $\mathbb{R}^d$. Our result shows that, the number of weights needed to $\epsilon$-approximate a bandlimited function using the GNN architecture is much fewer than the best known one using a fully connected neural network (NN) - in particular, one only needs $O((\log \epsilon^{-1})^{d})$ weights using a GNN trained by $O((\log \epsilon^{-1})^{d})$ samples to $\epsilon$-approximate a discretized bandlimited signal in $\mathbb{R}^d$. The result is obtained by drawing a connection between the GNN structure and the classical sampling theorems, making our work the first attempt in this direction

Risk factors for falls among community-dwelling older adults: A systematic review and meta-analysis

Background and objectiveThe prevalence of falls among older adults living in the community is ~30% each year. The impacts of falls are not only confined to the individual but also affect families and the community. Injury from a fall also imposes a heavy financial burden on patients and their families. Currently, there are different reports on the risk factors for falls among older adults in the community. A retrospective analysis was used in this study to identify risk factors for falls in community-dwelling older adults. This research aimed to collect published studies to find risk factors for falls in community-dwelling older adults.MethodsWe searched for literature from the founding of PubMed, EMBASE, the Cochrane Library, the Web of Science, the China National Knowledge Infrastructure (CNKI), the China Science and Technology Periodicals Database (VIP), and the Wanfang database until September 2022. The studies were selected using inclusion and exclusion criteria. We collected information from relevant studies to compare the impact of potential risk factors such as age, female gender, fear of falling, history of falls, unclear vision, depression, and balance disorder on falls among community-dwelling older adults.ResultsA total of 31 studies were included with 70,868 community seniors. A significant risk factor for falls in the community of older adults was dementia (2.01, 95% CI: 1.41–2.86), age (1.15, 95% CI: 1.09–1.22), female gender (1.52, 95% CI: 1.27–1.81), fear of falling (2.82, 95% CI: 1.68–4.74), history of falls (3.22, 95% CI: 1.98–5.23), vision unclear (1.56, 95% CI: 1.29–1.89), depression (1.23, 95% CI: 1.10–1.37), and balance disorder (3.00, 95% CI: 2.05–4.39).ConclusionThis study provides preliminary evidence that falls among community-dwelling older adults are associated with factors such as age, female gender, fear of falling, history of falls, unclear vision, depression, and balance disorders. The results of this research may help improve clinician awareness, risk stratification, and fall prevention among community-dwelling older adults.Systematic review registrationidentifier INPLASY2022120080

Comparison of Quality and Antioxidant Activity of Fu Brick Tea in Different Regions, and Its "Golden Flower" Fungi Morphological Characteristics

The chemical composition, quality characteristics, antioxidant activity, and "golden flower" fungi morphology of Fu brick tea from Hunan, Hubei, Shaanxi, Guizhou, and Zhejiang provinces of China had been researched in this study. The results revealed significant differences in the contents of chemical components in different Fu brick tea (P<0.05). Among them, Fu brick tea from Guizhou had the highest contents of free amino acids and total catechins (9.03, 63.12 mg/g, respectively), while Zhejiang Fu brick tea standed out with the most elevated content of tea polyphenols and flavonoids (132.93, 8.63 mg/g, respectively). According to the electronic taste evaluation, the Fu brick tea from Hunan and Shaanxi exhibited the strongest bitterness and astringency, respectively. Meanwhile，the Zhejiang sample had the most powerful aftertaste bitterness and saltiness, whereas the Guizhou sample demonstrated the strongest umami and richness. Different Fu brick teas had different antioxidant activities, with samples from Hubei and Zhejiang showing higher levels of antioxidant activity. Correlation analysis revealed a significant positive correlation between the main chemical components and taste attributes, and tea polyphenols contributed to the antioxidant activity of Fu brick tea. Additionally, morphology indicated that the five strains of "golden flower" fungi from different origins showed slight differences in the same medium, while the Hunan strain grew faster than the others. This study taked an important role in comprehending the chemical quality of Fu brick tea from different origins

Germline SDHB and SDHD Mutations in Pheochromocytoma and Paraganglioma Patients

Pheochromocytoma and paragangliomas (PCC/PGL) are neuroendocrine tumors that arise from chromaffin cells of the adrenal medulla and sympathetic/parasympathetic ganglia, respectively. Of clinical relevance regarding diagnosis is the highly variable presentation of symptoms in PCC/PGL patients. To date, the clear-cut correlations between the genotypes and phenotypes of PCC/PGL have not been entirely established. In this study, we reviewed the medical records of PCC/PGL patients with pertinent clinical, laboratory and genetic information. Next-generation sequencing (NGS) performed on patient samples revealed specific germline mutations in the SDHB (succinate dehydrogenase complex iron-sulfur subunit B) and SDHD（succinate dehydrogenase complex subunit D) genes and these mutations were validated by Sanger sequencing. Of the 119 patients, two were identified with SDHB mutation and one with SDHD mutation. Immunohistochemical (IHC) staining was used to analyze the expression of these mutated genes. The germline mutations identified in the SDH genes were: c343C\u3eT and c.541-542A\u3eG in the SDHB gene and c.334-337delACTG in the SDHD gene. IHC staining of tumors from the c.343C\u3eT and c.541-2A\u3eG carriers showed positive expression of SDHB. Tumors from the c.334-337delACTG carrier showed no expression of SDHD and a weak diffused staining pattern for SDHB. We strongly recommend genetic testing for suspected PCC/PGL patients with a positive family history, early onset of age, erratic hypertension, recurrence or multiple tumor sites and loss of SDHB and/or SDHD expression. Tailored personal management should be conducted once a patient is confirmed as an SDHB and/or SDHD mutation carrier or diagnosed with PCC/PGL

Assessing the Carbon Emission Driven by the Consumption of Carbohydrate-Rich Foods: The Case of China

peer-reviewedBackground: Carbohydrate-rich (CR) foods are essential parts of the Chinese diet. However, CR foods are often given less attention than animal-based foods. The objectives of this study were to analyze the carbon emissions caused by CR foods and to generate sustainable diets with low climate impact and adequate nutrients. Methods: Twelve common CR food consumption records from 4857 individuals were analyzed using K-means clustering algorithms. Furthermore, linear programming was used to generate optimized diets. Results: Total carbon emissions by CR foods was 683.38g CO2eq per day per capita, accounting for an annual total of 341.9Mt CO2eq. All individuals were ultimately divided into eight clusters, and none of the popular clusters were low carbon or nutrient sufficient. Optimized diets could reduce about 40% of carbon emissions compared to the average current diet. However, significant structural differences exist between the current diet and optimized diets. Conclusions: To reduce carbon emissions from the food chain, CR foods should be a research focus. Current Chinese diets need a big change to achieve positive environmental and health goals. The reduction of rice and wheat-based foods and an increase of bean foods were the focus of structural dietary change in CR food consumption.Natural Science Foundation of Guangdong Provinc

Targeting the Transforming Growth Factor-β pathway inhibits human basal-like breast cancer metastasis

<p>Abstract</p> <p>Background</p> <p>Transforming Growth Factor β (TGF-β) plays an important role in tumor invasion and metastasis. We set out to investigate the possible clinical utility of TGF-β antagonists in a human metastatic basal-like breast cancer model. We examined the effects of two types of the TGF-β pathway antagonists (1D11, a mouse monoclonal pan-TGF-β neutralizing antibody and LY2109761, a chemical inhibitor of TGF-β type I and II receptor kinases) on sublines of basal cell-like MDA-MB-231 human breast carcinoma cells that preferentially metastasize to lungs (4175TR, 4173) or bones (SCP2TR, SCP25TR, 2860TR, 3847TR).</p> <p>Results</p> <p>Both 1D11 and LY2109761 effectively blocked TGF-β-induced phosphorylation of receptor-associated Smads in all MDA-MB-231 subclones <it>in vitro</it>. Moreover, both antagonists inhibited TGF-β stimulated <it>in vitro </it>migration and invasiveness of MDA-MB-231 subclones, indicating that these processes are partly driven by TGF-β. In addition, both antagonists significantly reduced the metastatic burden to either lungs or bones <it>in vivo</it>, seemingly independently of intrinsic differences between the individual tumor cell clones. Besides inhibiting metastasis in a tumor cell autonomous manner, the TGF-β antagonists inhibited angiogenesis associated with lung metastases and osteoclast number and activity associated with lytic bone metastases. In aggregate, these studies support the notion that TGF-β plays an important role in both bone-and lung metastases of basal-like breast cancer, and that inhibiting TGF-β signaling results in a therapeutic effect independently of the tissue-tropism of the metastatic cells. Targeting the TGF-β pathway holds promise as a novel therapeutic approach for metastatic basal-like breast cancer.</p> <p>Conclusions</p> <p>In aggregate, these studies support the notion that TGF-β plays an important role in both bone-and lung metastases of basal-like breast cancer, and that inhibiting TGF-β signaling results in a therapeutic effect independently of the tissue-tropism of the metastatic cells. Targeting the TGF-β pathway holds promise as a novel therapeutic approach for metastatic basal-like breast cancer.</p