The Rationality of Addiction

This paper presents a discussion on the rationality of addiction using economic theories. Drug abuse is the dominant context for addict ion in this paper. However, it does not preclude a broader definition, encapsulating dependence on substances other than pharmacological agents; let it be nicotine , alcohol, coffee, chocolates or sex. The argument follows the progression in rationale from consumption to addiction to eventual remission. The economics of any behaviour, addiction-motivated or otherwise, distils down to the scarcity of means and our intuitions of opportunity costs involved in making a choice. The two concepts are interrelated. The process of decision-making weighs the benefit of each choice (its marginal utility) against its opportunity cost. In utility maximization theory, money is a scarce resource assumed important for maximizing utility. Therefore, choice on consumption is decided by the relative price between two goods. Overall utility is maximized when the ratio of the prices of two desired goods is equal to their marginal rate of substitution – the ratio of their marginal utilities. That is, the objective or source of utility for a consumer is to maximi ze the total value of their available money

VeCLIP: Improving CLIP Training via Visual-enriched Captions

Large-scale web-crawled datasets are fundamental for the success of pre-training vision-language models, such as CLIP. However, the inherent noise and potential irrelevance of web-crawled AltTexts pose challenges in achieving precise image-text alignment. Existing methods utilizing large language models (LLMs) for caption rewriting have shown promise on small, curated datasets like CC3M and CC12M. This study introduces a scalable pipeline for noisy caption rewriting. Unlike recent LLM rewriting techniques, we emphasize the incorporation of visual concepts into captions, termed as Visual-enriched Captions (VeCap). To ensure data diversity, we propose a novel mixed training scheme that optimizes the utilization of AltTexts alongside newly generated VeCap. We showcase the adaptation of this method for training CLIP on large-scale web-crawled datasets, termed VeCLIP. Employing this cost-effective pipeline, we effortlessly scale our dataset up to 300 million samples named VeCap dataset. Our results show significant advantages in image-text alignment and overall model performance. For example, VeCLIP achieves up to +25.2% gain in COCO and Flickr30k retrieval tasks under the 12M setting. For data efficiency, VeCLIP achieves +3% gain while only using 14% of the data employed in the vanilla CLIP and 11% in ALIGN. We also note the VeCap data is complementary with other well curated datasets good for zero-shot classification tasks. When combining VeCap and DFN, our model can achieve strong performance on both of image-text retrieval and zero-shot classification tasks, e.g. 83.1% accuracy@1 on ImageNet zero-shot for a H/14 model. We release the pre-trained models at https://github.com/apple/ml-veclip.Comment: CV/M

Hyphal Development in Candida albicans Requires Two Temporally Linked Changes in Promoter Chromatin for Initiation and Maintenance

Phenotypic plasticity is common in development. For Candida albicans, the most common cause of invasive fungal infections in humans, morphological plasticity is its defining feature and is critical for its pathogenesis. Unlike other fungal pathogens that exist primarily in either yeast or hyphal forms, C. albicans is able to switch reversibly between yeast and hyphal growth forms in response to environmental cues. Although many regulators have been found involved in hyphal development, the mechanisms of regulating hyphal development and plasticity of dimorphism remain unclear. Here we show that hyphal development involves two sequential regulations of the promoter chromatin of hypha-specific genes. Initiation requires a rapid but temporary disappearance of the Nrg1 transcriptional repressor of hyphal morphogenesis via activation of the cAMP-PKA pathway. Maintenance requires promoter recruitment of Hda1 histone deacetylase under reduced Tor1 (target of rapamycin) signaling. Hda1 deacetylates a subunit of the NuA4 histone acetyltransferase module, leading to eviction of the NuA4 acetyltransferase module and blockage of Nrg1 access to promoters of hypha-specific genes. Promoter recruitment of Hda1 for hyphal maintenance happens only during the period when Nrg1 is gone. The sequential regulation of hyphal development by the activation of the cAMP-PKA pathway and reduced Tor1 signaling provides a molecular mechanism for plasticity of dimorphism and how C. albicans adapts to the varied host environments in pathogenesis. Such temporally linked regulation of promoter chromatin by different signaling pathways provides a unique mechanism for integrating multiple signals during development and cell fate specification

The response of phytoplankton communities to experimentally elevated temperatures in the presence and absence of Potamogeton crispus

Phytoplankton in shallow lakes will expectedly respond to climate warming and the response may differ between macrophyte and non-macrophyte lakes. To test the responses of phytoplankton to elevated temperature (+ 4.5 degrees C) at genus and functional group level, we conducted a 60-day experiment with and without the presence of Potamogeton crispus in the winter of Wuhan, China. When P. crispus was present, elevated temperature had little or no effect on the biomass and composition of the phytoplankton community. In the absence of P. crispus, however, elevated temperature significantly decreased the biomass and changed the composition of the phytoplankton. In contrast to many but not all published results mainly conducted during spring and summer, elevated temperature in winter reduced rather than increased the dominance of Cyanophyta. Instead, Chlorophyta became dominant. Redundancy analyses (RDA) showed that conductivity, light intensity and the ammonium/nitrate ratio (NH4:NO3) were the most important environmental variables, accounting for almost similar parts of the variations recorded in both genus and functional group composition. Among treatments, functional models did not show advantages over taxonomic models in depicting the response of the phytoplankton assemblage to the environmental conditions prevailing in our study conducted in winter, characterised by low phytoplankton abundance

Seasonality and Species Specificity of Submerged Macrophyte Biomass in Shallow Lakes Under the Influence of Climate Warming and Eutrophication

Climate warming and eutrophication caused by anthropogenic activities strongly affect aquatic ecosystems. Submerged macrophytes usually play a key role in shallow lakes and can maintain a stable clear state. It is extremely important to study the effects of climate warming and eutrophication on the growth of submerged macrophytes in shallow lakes. However, the responses of submerged macrophytes to climate warming and eutrophication are still controversial. Additionally, the understanding of the main pathways impacting submerged macrophytes remains to be clarified. In addition, the influence of seasonality on the growth responses of submerged macrophytes to climate warming and eutrophication requires further elucidation. In this study, we conducted a series of mesocosm experiments with four replicates across four seasons to study the effects of rising temperature and nutrient enrichment on the biomass of two submerged macrophytes, Potamogeton crispus and Elodea canadensis. Our results demonstrated the seasonality and species specificity of plant biomass under the influence of climate warming and eutrophication, as well as the main explanatory factors in each season. Consistent with the seasonal results, the overall results showed that E. canadensis biomass was directly increased by rising temperature rather than by nutrient enrichment. Conversely, the overall results showed that P. crispus biomass was indirectly reduced by phosphorus enrichment via the strengthening of competition among primary producers. Distinct physiological and morphological traits may induce species-specific responses of submerged macrophytes to climate warming and eutrophication, indicating that further research should take interspecies differences into account.</jats:p