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"Gray, Joseph"
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Hurricanes : be aware and prepare
\"Describes how hurricanes form, their effects, and how people can prepare for them\"--Provided by publisher.
Book
Reference Curves for Central Appalachian Red Spruce
Red spruce (Picea rubens Sarg.) was a prized timber species in West Virginia during the era of resource exploitation in the late 1800s and early 1900s. As a result, central Appalachian red spruce comprise a much smaller component of high-elevation stand composition and a greatly constricted presence across the region. Widespread restoration efforts are underway to re-establish red spruce across this landscape. However, without benchmarks to gauge growth rates and stand developmental patterns, it is unclear whether these efforts are successful. Our goal was to develop reference curves predicting centile height growth for understory red spruce (≤7.6 m) across the region. We reconstructed the height growth patterns of over 250 randomly selected red spruce seedlings and saplings from 22 high-elevation stands in West Virginia. We also harvested 24 mature red spruce from the same stands to develop juvenile growth curves up to 7.6 m to compare understory growth rates of historical to contemporary rates from the reference curves. Our constructed reference curves showed height growth tended to peak between 10 and 30 years of age. Total heights ranged from 0.95 m to 6.85 m after 50 years. We identified two demographic populations in the mature red spruce trees. All the mature red spruce trees that established after 1890 exceeded the 97% growth centile by age 80. By contrast, only two trees from the pre-1890 population reached the same level by age 80. This work highlights the varied ascension pathways to the overstory for red spruce.
Journal Article
The goose and the golden eggs
A modern song retells the fable of a farmer whose goose lays golden eggs but whose greed keeps him wanting more. Includes a brief introduction to Aesop, sheet music, glossary, discussion questions, and further reading.
Book
Complex pectin metabolism by gut bacteria reveals novel catalytic functions
The metabolism of carbohydrate polymers drives microbial diversity in the human gut microbiota. It is unclear, however, whether bacterial consortia or single organisms are required to depolymerize highly complex glycans. Here we show that the gut bacterium
Bacteroides thetaiotaomicron
uses the most structurally complex glycan known: the plant pectic polysaccharide rhamnogalacturonan-II, cleaving all but 1 of its 21 distinct glycosidic linkages. The deconstruction of rhamnogalacturonan-II side chains and backbone are coordinated to overcome steric constraints, and the degradation involves previously undiscovered enzyme families and catalytic activities. The degradation system informs revision of the current structural model of rhamnogalacturonan-II and highlights how individual gut bacteria orchestrate manifold enzymes to metabolize the most challenging glycan in the human diet.
The hierarchical deconstruction of the complex pectic glycan rhamnogalacturonan-II by the human gut bacterium
Bacteroides thetaiotaomicron
reveals seven new families of glycoside hydrolases and three catalytic functions not previously observed.
Pectin breakdown in the gut
Rhamnogalacturonan-II (RG-II) is the most complex glycan known. It has been a feature of the human diet since the time of the Neanderthals, but the mechanism by which this polysaccharide is broken down is unknown. In this work, the authors dissect the key processes and enzyme families in the gut that are involved in RG-II deconstruction. A single gut bacteria from the Bacteroides phylum metabolizes this complex substrate by cleaving all but one of the 21 glycosidic linkages. This degradation process involves seven newly discovered families of glycoside hydrolases, as well as novel catalytic functions of several known enzymes. This work delves deep into the mechanisms of glycan degradation by bacteria in the human gut microbiota and how they have evolved with this degradation to utilize rare sugars.
Journal Article
الإدارة في المواقف الضبابية : 5 أسئلة دائمة لحل أصعب مشكلاتك في العمل
كلما تحملت المزيد من المسئولية في العمل والحياة، زاد تكرار ما تواجهه من مشكلات المنطقة الضبابية، وهذه المشكلات تأتي في جميع الأشكال والأحجام. على سبيل المثال، بعضها كبير، ومعقد، وغير متكرر. في وقت لاحق في هذا الكتاب، سنبحث بالتفصيل موقفا واجهه الرئيس التنفيذي لشركة صغيرة للتكنولوجيا الحيوية عرف أن أحد الأدوية الجديدة الذي تشتد الحاجة إليه قد يكون متورطا في مرض دماغي نادر جدا، لكنه فتاك كان عليه أن يقرر ما يجب القيام به، على الرغم من أنه افتقر إلى حقائق حرجة أو حتى تعريف واضح للمشكلة.
Book
An Evolutionarily Conserved Laterally Acquired Toolkit Enables Microbiota Targeting by Trichomonas
Abstract
Trichomonas species are a diverse group of microbial eukaryotes (also commonly referred to as protists) that are obligate extracellular symbionts associated with or attributed to various inflammatory diseases. They colonize mucosal surfaces across a wide range of hosts, all of which harbor a resident microbiota. Their evolutionary history likely involved multiple host transfers, including zoonotic events from columbiform birds to mammals. Using comparative transcriptomics, this study examines Trichomonas gallinae co-cultured with Escherichia coli, identifying a molecular toolkit that Trichomonas species may use to interact with bacterial members of the microbiota. Integrating transcriptomic data with comparative genomics and phylogenetics revealed a conserved repertoire of protein-coding genes likely acquired through multiple lateral gene transfers (LGTs) in a columbiform-infecting ancestor. These LGT-derived genes encode muramidases, glucosaminidases, and antimicrobial peptides—enzymes and effectors capable of targeting bacterial cell walls, potentially affecting the bacterial-microbiota composition across both avian and mammalian hosts. This molecular toolkit suggests that Trichomonas species can actively compete with and exploit their surrounding microbiota for nutrients, potentially contributing to dysbiosis associated with Trichomonas infections. Their ability to target bacterial populations at mucosal surfaces provides insight into how Trichomonas species may have adapted to diverse hosts and how they could influence inflammatory mucosal diseases in birds and mammals.
Journal Article
Untraceable
Jennifer Marsh is an FBI secret service agent who gets caught up in a very personal and deadly cat-and-mouse game with a serial killer. The killer knows that people are drawn to the curious and the dark side of things. They will log onto an 'untraceable' website where the killer conducts violent and painful murders live on the internet. The more people who log on and enter the website, the quicker and more violently the victim dies.
DVD
Crystal Domain Mapping with Polarized Raman Spectroscopy and Chi-(2) Nonlinear Optics in CMOS Waveguides
Polarized Raman spectra collected from a diffraction-limited spatial volume constitute a versatile scanning probe. Polarization selection rules for Raman scattering in crystals provide a signature of local symmetry and orientation. Making use of this, I demonstrate orientation-resolved domain mapping in tetragonal strontium titanate (SrTiO3) and discuss the relevance of this technique to the study of electronic materials exhibiting emergent spatial inhomogeneity. In Second-order nonlinear optical susceptibility is forbidden to dipole order in inversion-symmetric media, however this rule can be broken with an applied DC electric field. Historically known as electric field induced second harmonic (EFISH) generation, this effect can be understood as four-wave mixing between three optical electric fields and one DC electric field. The dense integration of microelectronic devices with optical waveguides available in CMOS photonics enables strong EFISH using relatively modest voltages and periodically-poled DC electric fields for quasi-phase- matched three-wave mixing. I will discuss device design and characterization efforts aimed at developing on-chip optical parametric oscillators and up-conversion detectors for mid- infrared light.
Dissertation