Hasil untuk "Biology (General)"

Aitor Lewkowycz, Anders Andreassen, David Dohan et al.

Language models have achieved remarkable performance on a wide range of tasks that require natural language understanding. Nevertheless, state-of-the-art models have generally struggled with tasks that require quantitative reasoning, such as solving mathematics, science, and engineering problems at the college level. To help close this gap, we introduce Minerva, a large language model pretrained on general natural language data and further trained on technical content. The model achieves state-of-the-art performance on technical benchmarks without the use of external tools. We also evaluate our model on over two hundred undergraduate-level problems in physics, biology, chemistry, economics, and other sciences that require quantitative reasoning, and find that the model can correctly answer nearly a third of them.

Yu Chen, Qianyun Liu, D. Guo

K. John-Alder

Objective To learn more about Biomedical Engineering and potentially obtain a lab position at the Tan Laboratory. I finished core classes for engineering and biology I took Engineering Calculus, General Chemistry and the Introductory Biology series. I learned a bit about synthetic and metabolic pathways in Bis2A. I also took Statistics and Upper-Division Economics. My professors were focused on using Excel to compute various statistics and spreadsheet calculations in Excel because that was what professionals were doing using the knowledge we learned in class. Thus, I am quite skilled in Excel. I continued on with classes, but my more relevant classes were organic chemistry, biochemistry, linear algebra, and econometrics. In organic chemistry, I learned about synthesis, NMR, IR, and I gained an understanding of how reaction mechanisms and protecting groups. In the last course of the series, the professor focused on bio-organic chemistry, which enabled me to better understand the reactions occurring in the human body. In biochemistry, I learned about the properties of the 20 amino acids, about protein purification, and about catalysts, enzymes, and how proteins function. In econometrics and linear algebra, I learned more about data analysis and how to compute regressions and other basic data analysis. My coursework was supplemented by learning a bit about Matlab and Stata. Over 300 hours of experience and community service from High School at UCI Med Center. I was a distinguished volunteer because I was the first volunteer to receive a thank you letter in all of the volunteer department's history. At UCD Med Center, I volunteered in the SICU. I am learning more about patient interactions, patient care, as well as secretarial work like answering phones and keeping track of multiple calls at once. With the College of Biology, I am currently enrolled in the Peer-Mentorship Program, where I offer advice to a freshman mentee to ease the transition from high school to college. I learned about what it takes to be a good role model and inspiration, and I intend to continue inspiring others in my life.\

Alexei J. Drummond, M. Suchard, Dong Xie et al.

Computational evolutionary biology, statistical phylogenetics and coalescent-based population genetics are becoming increasingly central to the analysis and understanding of molecular sequence data. We present the Bayesian Evolutionary Analysis by Sampling Trees (BEAST) software package version 1.7, which implements a family of Markov chain Monte Carlo (MCMC) algorithms for Bayesian phylogenetic inference, divergence time dating, coalescent analysis, phylogeography and related molecular evolutionary analyses. This package includes an enhanced graphical user interface program called Bayesian Evolutionary Analysis Utility (BEAUti) that enables access to advanced models for molecular sequence and phenotypic trait evolution that were previously available to developers only. The package also provides new tools for visualizing and summarizing multispecies coalescent and phylogeographic analyses. BEAUti and BEAST 1.7 are open source under the GNU lesser general public license and available at http://beast-mcmc.googlecode.com and http://beast.bio.ed.ac.uk

V. Lushchak

L. Kelley, M. Sternberg

K. Fukunaga

S. Sherry, Minghong Ward, Michael Kholodov et al.

R. Prior, Xianli Wu, K. Schaich

Christian Dubos, R. Stracke, E. Grotewold et al.

Freya Q. Schafer, G. Buettner

R. H. Myers

H. Maturana, F. Varela

H. Birx, R. Leakey, E. Dutton et al.

P. Ehrlich, P. Raven

J. Massagué, J. Seoane, D. Wotton

Smad transcription factors lie at the core of one of the most versatile cytokine signaling pathways in metazoan biology-the transforming growth factor-beta (TGFbeta) pathway. Recent progress has shed light into the processes of Smad activation and deactivation, nucleocytoplasmic dynamics, and assembly of transcriptional complexes. A rich repertoire of regulatory devices exerts control over each step of the Smad pathway. This knowledge is enabling work on more complex questions about the organization, integration, and modulation of Smad-dependent transcriptional programs. We are beginning to uncover self-enabled gene response cascades, graded Smad response mechanisms, and Smad-dependent synexpression groups. Our growing understanding of TGFbeta signaling through the Smad pathway provides general principles for how animal cells translate complex inputs into concrete behavior.

D. Culver, T. Pipan

Caves and other subterranean habitats with their often strange (even bizarre) inhabitants have long been objects of fascination, curiosity, and debate. The question of how such organisms have evolved, and the relative roles of natural selection and genetic drift, has engaged subterranean biologists for decades. Indeed, these studies continue to inform the general theory of adaptation and evolution. Subterranean ecosystems generally exhibit little or no primary productivity and, as extreme ecosystems, provide general insights into ecosystem function. The Biology of Caves and other Subterranean Habitats offers a concise but comprehensive introduction to cave ecology and evolution. Whilst there is an emphasis on biological processes occurring in these unique environments, conservation and management aspects are also considered. The monograph includes a global range of examples from more than 25 countries, and case studies from both caves and non-cave subterranean habitats; it also provides a clear explanation of specialized terms used by speleologists. This accessible text will appeal to researchers new to the field and to the many professional ecologists and conservation practitioners requiring a concise but authoritative overview. Its engaging style will also make it suitable for undergraduate and graduate students taking courses in cave and subterranean biology. Its more than 650 references, 150 of which are new since the first edition, provide many entry points to the research literature.

Balkar Yildirim, Alan Albert Coley, Diego Fernando López

We investigate whether black holes can persist through the bounce with a minimal scale factor in a non-singular cosmology, whereby black holes from a previous contracting phase survive into the current expanding one. We do so by studying a generalized McVittie spacetime which embeds a spherically symmetric black hole in a positive spatial curvature bouncing FLRW cosmological background within the modified theory of teleparallel new general relativity. There are no further assumptions on the spacetime (e.g., on the form of the scale factor) initially, and the local evolution is derived from the field equations of the theory, utilizing a perturbative scheme which is valid ``near the bounce". To leading order we obtain a simple bounce solution similar to that in general relativity for a closed FLRW model with a positive cosmological constant, but in which the curvature term in the Friedmann equation is re-normalized within new general relativity. Qualitatively the minimum of the bounce at $t=0$ changes, but near the bounce the evolution remains symmetric. The central inhomogeneity evolves at higher perturbative orders, where the details depend on the arbitrary constants of the perturbative solution. Hence the evolution of the local horizon during the bounce changes qualitatively, where the effects depend on the signs of the perturbation, and the symmetry across the bounce is disrupted due to a linear term.

Anna Wajs-Bonikowska, Ewa Maciejczyk, Łukasz Szoka et al.

This study investigates the essential oil (EO) isolated from the seeds and cones of Canadian hemlock (<i>Tsuga canadensis</i>), highlighting notable differences in their chemical composition and biological activities. The seed EO was uniquely dominated by oxygenated derivatives of monoterpene hydrocarbons, particularly bornyl acetate (40%), whereas the cone EO exhibited higher levels of monoterpene hydrocarbons such as α-pinene (23%), β-pinene (20%), and myrcene (23%). A significant finding was the strong cytotoxic activity of cone EO against melanoma cell lines, with IC₅₀ values as low as 0.104 ± 0.015 μL/mL, compared to the minimal effects of seed EO. Additionally, cone EO demonstrated stronger antimicrobial activity, with lower minimum inhibitory concentrations (MICs) against Gram-positive and Gram-negative bacteria, further highlighting its therapeutic potential. Lipophilic extracts from seeds were characterized by unsaturated fatty acids (linoleic, oleic, and sciadonic acids—specific to conifers) and bioactive molecules with high antioxidant and nutritional potential, such as β-tocopherol, β-sitosterol, and campestrol. These findings underscore the unique chemical composition of <i>T. canadensis</i> seed EO and its lipophilic extract, along with the potent cytotoxic and antimicrobial properties of cone EO, offering insights into their potential applications in natural products for pharmaceutical and therapeutic uses.

Min Liu, Yuanyuan Li, Zhilin Deng et al.

Abstract Mutation in genes involved in DNA replication continuously disrupt DNA replication and give rise to genomic instability, a critical driver of oncogenesis. To prevent leukemia, immature T lymphocytes with genomic instability often undergo rapid cell death during development. However, the mechanism by which immature T lymphocytes undergo rapid cell death upon genomic instability has been enigmatic. Here we show that zebrafish mcm5 mutation leads to DNA damage in immature T lymphocytes and the immature T cells sensitively undergo rapid cell death. Detailed analyses demonstrated that the immature T lymphocytes undergo rapid apoptosis via upregulation of tp53 and downregulation of bcl2 transcription in mcm5 mutants. Mechanistically, Mcm5 directly binds to Stat1a and facilitates its phosphorylation to enhance bcl2a expression under the conditions of DNA replication stress. However, in mcm5 mutants, the absence of the Mcm5-Stat1 complex decreases Stat1 phosphorylation and subsequent bcl2a transcription, accelerating apoptosis of immature T lymphocytes with genomic instability. Furthermore, our study shows that the role of Mcm5 in T-cell development is conserved in mice. In conclusion, our work identifies a role of Mcm5 in regulating T cell development via Stat1-Bcl2 cascade besides its role in DNA replication, providing a kind of mechanism by which immature T cells with gene mutation-induced DNA damage are rapidly cleared during T lymphocyte development.