25 research outputs found
Eurasian watermilfoil biomass associated with insect herbivores in New York
A study of aquatic plant biomass within Cayuga Lake, New
York spans twelve years from 1987-1998. The exotic Eurasian
watermilfoil
(
Myriophyllum spicatum
L.) decreased in the
northwest end of the lake from 55% of the total biomass in
1987 to 0.4% in 1998 and within the southwest end from
50% in 1987 to 11% in 1998. Concurrent with the watermilfoil
decline was the resurgence of native species of submersed
macrophytes. During this time we recorded for the
first time in Cayuga Lake two herbivorous insect species: the
aquatic moth
Acentria ephemerella
, first observed in 1991, and
the aquatic weevil
Euhrychiopsis lecontei
, first found in 1996
.
Densities of
Acentria
in southwest Cayuga Lake averaged 1.04
individuals per apical meristem of Eurasian watermilfoil for
the three-year period 1996-1998. These same meristems had
Euhrychiopsis
densities on average of only 0.02 individuals per
apical meristem over the same three-year period. A comparison
of herbivore densities and lake sizes from five lakes in
1997 shows that
Acentria
densities correlate positively with
lake surface area and mean depth, while
Euhrychiopsis
densities
correlate negatively with lake surface area and mean
depth. In these five lakes,
Acentria
densities correlate negatively
with percent composition and dry mass of watermilfoil.
However,
Euhrychiopsis
densities correlate positively with percent
composition and dry mass of watermilfoil. Finally,
Acentria
densities correlate negatively with
Euhrychiopsis
densities
suggesting interspecific competition
A multi-modal approach to measuring particulate iron speciation in buoyant hydrothermal plumes
Processes active within buoyant hydrothermal plumes are expected to modulate the flux of elements, such as Fe, to the deep ocean; however, they are yet to be described in a comprehensive manner through observations or models. In this study, we compare observed particulate Fe (pFe) speciation with thermodynamic (equilibrium) reaction path modeling for three vent fields in the Eastern Lau Spreading Center (ELSC). At each site, particles were collected from the buoyant rising portion of hydrothermal plumes using in situ filtration with a Remotely Operated Vehicle. Filter bound particles were analyzed by synchrotron micro-probe X-ray fluorescence mapping (XRF), X-ray diffraction (XRD), XRF spectroscopy, and X-ray absorption near edge structure (XANES) spectroscopy at the Fe 1 s edge, as well as XRF-based chemical speciation mapping for Fe. For buoyant plumes of the ELSC, diversity in solid-state chemistry was high, and poorly crystalline, meta-stable phases were common. We demonstrate that to fully describe the crystalline-to-noncrystalline character of plume pFe, a multi-modal XRD-XANES analytical approach is needed. We found that an equilibrium modeling approach worked well for pyrite but performed poorly for important families of meta-stable pFe, namely Fe (oxyhydr)oxides and monosulfides. Based on our findings, we recommend future field expeditions strategically explore sites representing a diversity of site-specific conditions to better capture the full range of processes active in plumes. We also recommend development of kinetic models, as well as expansion of thermodynamic databases to better reflect the solid-state composition of plumes. These steps should allow oceanographers to understand the processes controlling Fe speciation in plumes well enough to create realistic models of hydrothermal fluxes to the ocean
Leviathan on trial: Should states be held criminally responsible?
AbstractMany political theorists, philosophers, and International Relations scholars argue that states are ‘corporate moral agents’, which can be held responsible in many of the same ways as individual moral agents. States can have debts, contractual obligations, reparative obligations, and duties. Should states also be subject to criminal responsibility and punishment? Thus far, the debate about state crime has focused on two general problems with corporate crime: whether corporate entities can have intentions (or mens rea); and whether it is possible to punish them. In this paper, I identify two problems with extending corporate criminal responsibility to the state. First, since there is no ‘international corporate law’ that regulates the internal structures of states, many states fail to meet the conditions for corporate agency (and hence for criminal responsibility). Second, since the most serious international crimes are not subject to a statute of limitations, the argument for state crime paves the way for forms of ‘historical punishment’ that few of its proponents would accept. Finally, I argue that it is unnecessary to hold states criminally responsible, and that state responsibility ought to be understood as reparative rather than punitive.Non
Survival of CHO-TRET1 cells spin-dried in solutions with or without trehalose, then stored in LN<sub>2</sub> for 1 h, and finally rehydrated.
<p>(A) Membrane integrity of spin-dried cells stored in LN<sub>2</sub> for 1 h and 45 min after thawing and rehydration (B) Micrograph of the spin-dried cells after thawing and rehydration. (C) Growth of spin-dried cells after thawing and rehydration. The values were normalized to the initial cell count (<i>n</i> = 10, ± SD).</p
Glass transition temperature of the dried spinning solution (1.8 M trehalose, 10 mM KCl, 5 mM glucose, 20 mM HEPES, 120 mM choline chloride, pH 7.4) using FTIR technique.
<p>The figure indicates a characteristic peak-position of ν-OH stretch plotted against decreasing temperature.</p
Quantification of intracellular trehalose in wild-type CHO cells and CHO-TRET1 cells.
<p>Cells were incubated in fully complemented cell culture medium containing 400 mM trehalose for 4 hours (<i>n</i> = 3, ± SD).</p
Survival of CHO-TRET1 cells spin-dried in buffers with or without trehalose and rehydrated immediately following desiccation.
<p>(A) Membrane integrity of spin-dried cells 45 min after rehydration (B) Micrograph of the cell samples after spin drying and rehydration. (C) Growth of cells after spin-drying and rehydration. The values were normalized to the initial cell count (<i>n</i> = 10, ± SD).</p
FTIR analysis of the dried film obtained after spin drying of sample buffer (1.8 M trehalose, 10 mM KCl, 5 mM glucose, 20 mM HEPES, 120 mM choline chloride, pH 7.4).
<p>The ratio of I<sub>1650</sub>/I<sub>1150</sub> was used to quantify local water contents.</p
Basic configuration of the spin-drying apparatus.
<p>The cells were grown on glass cover slips prior to the spin-drying. During spin-drying, the glass cover slip was held in place by a vacuum chuck.</p