This book discusses the impact of recent advances in the theory of "scaling relationships" and identifies critical issues that must be considered if experimental results are used to understand the ...temporal and spatial scales of actual ecosystems.
The complexity of ecosystems complicates experimental design. How, for example, does a scientist draw boundaries when studying species effects and interactions? Once these boundaries are drawn, how does one treat factors external to that study? Will the failure to consider external factors affect one's ability to extrapolate information across temporal and spatial scales? This volume provides a compilation from a broad range of ecologists with extensive experimental research experience that addresses these and other questions of scaling relations.
Abstract
Oligochaetes (
Lumbriculus variegatus
) were exposed to sediment spiked with four
14
C‐polychlorinated alkanes (PCAs) (C
12
H
20
C
16
56% Cl by weight, C
12
H
16
Cl
10
69% Cl, C
16
H
31
Cl
3
...35% Cl, and C
16
H
21
Cl
13
69% Cl) to measure bioaccumulation parameters and biotransformation. Chlorinated paraffins are industrial products that consist of thousands of different PCAs. Chlorinated paraffins are hydrophobic (log octanol–water partition coefficients
K
ow
s > 5.0) and are reported to have relatively high concentrations in sediment compared with other persistent organochlorines; however, no data exist on their bioavailability from sediment. The PCAs C
12
H
20
Cl
6
, C
12
H
16
Cl
10
, and C
16
H
31
Cl
3
were readily available to sediment‐ingesting oligochaetes, whereas C
16
H
21
Cl
13
had lower bioavailability. Uptake rates of the C
12
‐PCAs were greater than the C
16
‐PCAs, but half‐lives (t
½
s) were greater for the C
16
‐PCAs (t
½
= 30‐33 d) than for the C
12
‐PCAs (t
½
= 12‐14 d). Biota–sediment accumulation factors were >1 for C
12
H
20
Cl
6
, C
12
H
16
Cl
10
, and C
16
H
31
Cl
3
, but <1 for C
16
H
21
Cl
13
. Comparison of toluene‐extractable and ‐nonextractable
14
C suggest that PCAs were biotransformed in aerobic sediments and by oligochaetes, and that the susceptibility to degradation in sediments decreases with increasing chlorine content. The relative abundance of individual PCAs may differ between sediment and benthic invertebrates because of differences in the bioaccumulation and degradation of PCAs of varying carbon chain length and chlorine content.
In 1994 health services in the Edmonton region were consolidated into an integrated network called Capital Health. Infection control professionals in the region met to develop a vision for the future ...of infection control; the tasks were to prepare a proposal for a regional program, develop indicators for outcome measurements, and standardize guidelines and products. Although regionalization of infection control is a complex process, we have had success with a proactive approach led by infection control professionals. (AJIC Am J Infect Control 1998;26:446-8)
This paper summarizes the work of the ad hoc Task Force on wind generation model validation. The paper describes the concept of model validation, how this applies to wind turbine generation systems ...and then gives clear examples of the most recent efforts to achieve model validation for wind turbine power plants. The document ends with a summary of the learning from the work presented and the conclusions which can be derived. Recommendations are made on the path forward for wind turbine generator modeling and model validation, primarily focused on generic models (i.e. standardized and publicly available) for stability analysis in power system studies.
Fifty outpatients with dysthymic disorder (DSM-III) were divided by double-blind randomized assignment into three groups given ritanserin, imipramine, and placebo, respectively. The trial was of 7 ...weeks' duration; by week 6, imipramine was clearly superior to placebo, whereas by week 7, both drugs caused significantly more improvement than the placebo. Although imipramine had slightly greater efficacy than ritanserin, it also had significantly more side effects. This was particularly evident in the higher dropout rate with imipramine. The efficacy and side effect profile of ritanserin makes it well tolerated and acceptable with dysthymic patients who, although they do not respond as quickly as patients with major depressive disorder, do show significant improvement, given sufficient time.
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