Lake Itasca State Park Myxomycetes: An Annotated Checklist

A lack of published information regarding Minnesota Myxomycetes prompted attempts to document species from Lake Itasca State Park in Clearwater county, in the northwest part of the state. Seventy-five species are herein recorded from 341 collections made during the years 1959, 1971,and 1975-78

Velocity-selective direct frequency-comb spectroscopy of atomic vapors

We present an experimental and theoretical investigation of two-photon direct frequency-comb spectroscopy performed through velocity-selective excitation. In particular, we explore the effect of repetition rate on the $\textrm{5S}_{1/2}\rightarrow \textrm{5D}_{3/2, 5/2}$ two-photon transitions excited in a rubidium atomic vapor cell. The transitions occur via step-wise excitation through the $\textrm{5P}_{1/2, 3/2}$ states by use of the direct output of an optical frequency comb. Experiments were performed with two different frequency combs, one with a repetition rate of $\approx 925$ MHz and one with a repetition rate of $\approx 250$ MHz. The experimental spectra are compared to each other and to a theoretical model.Comment: 10 pages, 7 figure

Magnetic field induced lattice anomaly inside the superconducting state of CeCoIn5_5: evidence of the proposed Fulde-Ferrell-Larkin-Ovchinnikov state

We report high magnetic field linear magnetostriction experiments on CeCoIn$_5$ single crystals. Two features are remarkable: (i) a sharp discontinuity in all the crystallographic axes associated with the upper superconducting critical field $B_{c2}$ that becomes less pronounced as the temperature increases; (ii) a distinctive second order-like feature observed only along the c-axis in the high field (10 T $\lesssim B \leq B_{c2}$) low temperature ($T \lesssim$ 0.35 K) region. This second order transition is observed only when the magnetic field lies within 20$^o$ of the ab-planes and there is no signature of it above $B_{c2}$, which raises questions regarding its interpretation as a field induced magnetically ordered phase. Good agreement with previous results suggests that this anomaly is related to the transition to the Fulde-Ferrel-Larkin-Ovchinnikov superconducting state.Comment: 3 figures, 5 page

Modeling the ecosystem services related to phytoextraction: Carbon sequestration potential using willow and poplar

Poplar and willow demonstrate great potential for the phytoextraction of trace elements (TEs) from soils. In most cases, these species are managed as short-rotation coppice, producing high woody biomass yields, which could provide a valuable contribution toward reducing greenhouse gas emissions in the atmosphere. In the current study, we compared the TE extraction and CO2 sequestration rates in a four-year field trial in Southern Italy of two arboreal species (willow and poplar). The results show that, once established in the study area, willow extracted more Cd and Cu and less Pb than poplar. The two species demonstrated the same average Ni and Zn extraction rates. Greater biomass yields in poplar suggest that this species was able to fix greater amounts of CO2 (28.7 Mg ha−1 yr−1) than willow (24.9 Mg ha−1 yr−1). We argue that the choice of the species to be used in phytoextraction should first be made considering the TE-specific affinity and phytoextraction rates. For TEs whose extraction rates were the same (i.e., Ni and Zn), poplar is to be preferred because of its ability to fix greater amounts of CO2 than willow

Trisomy 19 ependymoma, a newly recognized genetico-histological association, including clear cell ependymoma

Ependymal tumors constitute a clinicopathologically heterogeneous group of brain tumors. They vary in regard to their age at first symptom, localization, morphology and prognosis. Genetic data also suggests heterogeneity. We define a newly recognized subset of ependymal tumors, the trisomy 19 ependymoma. Histologically, they are compact lesions characterized by a rich branched capillary network amongst which tumoral cells are regularly distributed. When containing clear cells they are called clear cell ependymoma. Most trisomy 19 ependymomas are supratentorial WHO grade III tumors of the young. Genetically, they are associated with trisomy 19, and frequently with a deletion of 13q21.31-31.2, three copies of 11q13.3-13.4, and/or deletions on chromosome 9. These altered chromosomal regions are indicative of genes and pathways involved in trisomy 19 ependymoma tumorigenesis. Recognition of this genetico-histological entity allows better understanding and dissection of ependymal tumors

Baseline corticosterone in wintering marine birds: Methodological considerations and ecological patterns

Previous studies have related levels of plasma corticosterone (CORT) of seabirds to variation in foraging conditions during the breeding period, but it is unclear whether similar relationships between foraging conditions and baseline CORT exist during other life stages. We validated methods for identifying baseline CORT of lethally sampled birds and assessed variation in baseline CORT relative to winter habitat conditions. We collected free-living white-winged scoters (Melanitta fusca) at four wintering sites during December and February. We found increasing CORT values beyond 3 min after time since flush (the duration between initial flush and death), presumably reflecting acute stress responses. Our results demonstrate that it is possible to obtain baseline CORT from lethally sampled birds if the time from initial flush until death is measured. Our study sites varied appreciably in exposure to wind and waves, predation danger, diving depths, and the fraction of preferred foods in scoter diets. Despite these habitat differences, baseline CORT did not vary across sites or winter periods. We interpret this lack of variation as evidence that birds select wintering areas where they can successfully manage site-specific costs and maintain physiological homeostasis. © 2013 by The University of Chicago. All rights reserved

Baseline Corticosterone in Wintering Marine Birds: Methodological Considerations and Ecological Patterns

Previous studies have related levels of plasma corticosterone (CORT) of seabirds to variation in foraging conditions during the breeding period, but it is unclear whether similar relationships between foraging conditions and baseline CORT exist during other life stages. We validated methods for identifying baseline CORT of lethally sampled birds and assessed variation in baseline CORT relative to winter habitat conditions. We collected free-living white-winged scoters (Melanitta fusca) at four wintering sites during December and February. We found increasing CORT values beyond 3 min after time since flush (the duration between initial flush and death), presumably reflecting acute stress responses. Our results demonstrate that it is possible to obtain baseline CORT from lethally sampled birds if the time from initial flush until death is measured. Our study sites varied appreciably in exposure to wind and waves, predation danger, diving depths, and the fraction of preferred foods in scoter diets. Despite these habitat differences, baseline CORT did not vary across sites or winter periods. We interpret this lack of variation as evidence that birds select wintering areas where they can successfully manage site-specific costs and maintain physiological homeostasis