167 research outputs found
Trans-Mississippi Southerners in the Union Army, 1862-1865
Men from throughout the Trans-Mississippi South enlisted in the Union army during the Civil War both in existing northern regiments and in units raised specifically for the purpose of enlisting southerners. The men who joined and fought represented almost every social and ethnic division within the region and contributed substantially to the success of Union arms during the war. Examining a single regiment from each state or territory in the region (except Louisiana, where one white and one black unit were chosen due to segregation) reveals similarities of background, experience and purpose. Louisiana\u27s contributions to the Union army were primarily black soldiers, although a smaller number of white immigrants and freeholders also served. Texas\u27 contribution was equally divided between native-born southerners and Hispanics, while the Indian Territory contributed Native Americans from several southern tribes. Arkansas\u27 Union soldiers were split equally between white farmers from the northwestern corner of the state and freed slaves from the southeast. Service varied among the several regiments, but included active campaigning, anti-guerrilla operations and the far more mundane garrison duty. Men succumbed to disease in extraordinary numbers due in part to their position at the end of an extended logistic system in an ignored backwater of the war. These southerners represent the staunchest internal opposition to the Confederacy and contributed significantly to the restoration of Federal authority. Whatever their background these soldiers possessed a strong ideological attachment to the Union and endured severe hardships and oppression in order to vindicate a cause many valued more than their own lives
The Chicago Board of Trade Battery in the Civil War
In The Chicago Board of Trade Battery in the Civil War, Dennis W. Belcher not only illuminates the experiences of the batteryâs men, but âalso sheds new light on artillery unitsâ which reviewer Christopher M. Reign writes is âa topic of recent interest among military historians of the war.â The book is an âessential building blockâ from which future researchers will âbenefit,â Reign concludes
Leadership Lessons: The Campaigns for Vicksburg, 1862-1863
Taking Civil War Leaders to Task
Kevin Doughertyâs Leadership Lessons: The Campaigns for Vicksburg, 1862-1863 offers a concise summary of the events that led to the cityâs capture in July, 1863, but focuses on the campaignâs utility as a primer for modern leaders in âwar, busines...
The thermodynamics of computational copying in biochemical systems
Living cells use readout molecules to record the state of receptor proteins,
similar to measurements or copies in typical computational devices. But is this
analogy rigorous? Can cells be optimally efficient, and if not, why? We show
that, as in computation, a canonical biochemical readout network generates
correlations; extracting no work from these correlations sets a lower bound on
dissipation. For general input, the biochemical network cannot reach this
bound, even with arbitrarily slow reactions or weak thermodynamic driving. It
faces an accuracy-dissipation trade-off that is qualitatively distinct from and
worse than implied by the bound, and more complex steady-state copy processes
cannot perform better. Nonetheless, the cost remains close to the thermodynamic
bound unless accuracy is extremely high. Additionally, we show that
biomolecular reactions could be used in thermodynamically optimal devices under
exogenous manipulation of chemical fuels, suggesting an experimental system for
testing computational thermodynamics.Comment: Accepted versio
OSIRIS Payload for DLR's BiROS Satellite
Direct optical communication links might offer a solution for the increasing demand of transmission capacity in satellite missions. Although direct space-to-ground links suffer from limited availability due to cloud coverage, the achievable data rates can be higher by orders of magnitude compared to traditional RF communication systems.
DLRâs Institute for Communication and Navigation is currently developing an experimental communication payload for DLRâs BiROS satellite. The OSIRIS payload consists of a tracking sensor for a precise alignment between satellite and groundstation, an optical uplink channel, the two different and independent laser sources and the optical bench with the transmission optics.
This paper will give an overview about the BiROS satellite, the OSIRIS payload and the performance of the system, including space-qualification of the hardware and transmission tests
Using experimental and computational energy equilibration to understand hierarchical self-assembly of Fmoc-dipeptide amphiphiles
Despite progress, a fundamental understanding of the relationships between the molecular structure and self-assembly configuration of Fmoc-dipeptides is still in its infancy. In this work, we provide a combined experimental and computational approach that makes use of free energy equilibration of a number of related Fmoc-dipeptides to arrive at an atomistic model of Fmoc-threonine-phenylalanine-amide (Fmoc-TF-NH2) which forms twisted fibres. By using dynamic peptide libraries where closely related dipeptide sequences are dynamically exchanged to eventually favour the formation of the thermodynamically most stable configuration, the relative importance of C-terminus modifications (amide versus methyl ester) and contributions of aliphatic versus aromatic amino acids (phenylalanine F vs. leucine L) is determined (F > L and NH2 > OMe). The approach enables a comparative interpretation of spectroscopic data, which can then be used to aid the construction of the atomistic model of the most stable structure (Fmoc-TF-NH2). The comparison of the relative stabilities of the models using molecular dynamic simulations and the correlation with experimental data using dynamic peptide libraries and a range of spectroscopy methods (FTIR, CD, fluorescence) allow for the determination of the nanostructure with atomistic resolution. The final model obtained through this process is able to reproduce the experimentally observed formation of intertwining fibres for Fmoc-TF-NH2, providing information of the interactions involved in the hierarchical supramolecular self-assembly. The developed methodology and approach should be of general use for the characterization of supramolecular structures
Improving cartilage phenotype from differentiated pericytes in tunable peptide hydrogels
Differentiation of stem cells to chondrocytes in vitro usually results in a heterogeneous phenotype. This is evident in the often detected over expression of type X collagen which, in hyaline cartilage structure is not characteristic of the mid-zone but of the deep-zone ossifying tissue. Methods to better match cartilage developed in vitro to characteristic in vivo features are therefore highly desirable in regenerative medicine. This study compares phenotype characteristics between pericytes, obtained from human adipose tissue, differentiated using diphenylalanine/serine (F2/S) peptide hydrogels with the more widely used chemical induced method for chondrogenesis. Significantly higher levels of type II collagen were noted when pericytes undergo chondrogenesis in the hydrogel in the absence of induction media. There is also a balanced expression of collagen relative to aggrecan production, a feature which was biased toward collagen production when cells were cultured with induction media. Lastly, metabolic profiles of each system show considerable overlap between both differentiation methods but subtle differences which potentially give rise to their resultant phenotype can be ascertained. The study highlights how material and chemical alterations in the cellular microenvironment have wide ranging effects on resultant tissue type
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