A new species of Dichaea (Orchidaceae) for northern Brazil

Dichaea é o maior gênero da subtribo Zygopetalinae e possui sua maior diversidade de espécies na América do Sul. Diante disto, este trabalho teve o objetivo de descrever uma nova espécie de Dichaea ocorrente na região norte do Brasil, Dichaea bragae Valsko, Krahl & Holanda. A nova espécie foi coleta ao norte de Manaus em área de floresta ombrifila e floresceu em cultivo. O epíteto é em homenagem ao Dr. Pedro Ivo Soares Braga (in memorian), orquidilogo que realizou vários estudos na Amazônia brasileira. A nova espécie possui afinidade com espécies de Dichaea serão Dichaeopsis, contudo são diferenciadas vegetativamente e na morfologia do labelo

Cooperative Transition between Open and Closed Conformations in Potassium Channels

Potassium (K+) ion channels switch between open and closed conformations. The nature of this important transition was revealed by comparing the X-ray crystal structures of the MthK channel from Methanobacterium thermoautotrophicum, obtained in its open conformation, and the KcsA channel from Streptomyces lividans, obtained in its closed conformation. We analyzed the dynamic characteristics and energetics of these homotetrameric structures in order to study the role of the intersubunit cooperativity in this transition. For this, elastic models and in silico alanine-scanning mutagenesis were used, respectively. Reassuringly, the calculations manifested motion from the open (closed) towards the closed (open) conformation. The calculations also revealed a network of dynamically and energetically coupled residues. Interestingly, the network suggests coupling between the selectivity filter and the gate, which are located at the two ends of the channel pore. Coupling between these two regions was not observed in calculations that were conducted with the monomer, which emphasizes the importance of the intersubunit interactions within the tetrameric structure for the cooperative gating behavior of the channel

Information on Farms, Families, etc. - Sleeping Bear Dunes Region - Burdickville Area, 1933-circa 2010

Documents relating to local and family histories collected related to the Burdickville Area of the Sleeping Bear Dunes Region. Consists mainly of summaries and transcripts of oral history interviews, typically organized by track. Also includes some correspondence and histories in written forms.http://deepblue.lib.umich.edu/bitstream/2027.42/107683/1/Info-Burdickville.zi

Slavery and Plantation Capitalism in Louisiana's Sugar Country

Sugar planters in the antebellum South managed their estates progressively, efficiently, and with a political economy that reflected the emerging capitalist values of nineteenth-century America. By fusing economic progress and slave labor, sugar planters revolutionized the means of production and transformed the institution of slavery. Slaveholders and bondspeople redefined the parameters of paternalism and recast the master-slave relationship along a novel path. Louisiana slaves accommodated the machine, holding no torch for Luddism while concurrently shaping the agro-industrial revolution to achieve modest economic independence and relative autonomy within the plantation quarters