260 research outputs found
Asymptotically Hilbertian Modular Banach Spaces: Examples of Uncountable Categoricity
We give a criterion ensuring that the elementary class of a modular Banach
space E (that is, the class of Banach spaces, some ultrapower of which is
linearly isometric to an ultrapower of E) consists of all direct sums E\oplus_m
H, where H is an arbitrary Hilbert space and \oplus_m denotes the modular
direct sum. Also, we give several families of examples in the class of Nakano
direct sums of finite dimensional normed spaces that satisfy this criterion.
This yields many new examples of uncountably categorical Banach spaces, in the
model theory of Banach space structures.Comment: 20 page
A Uniform Method for Proving Lower Bounds of the Computational Complexity of Logical Theories
https://deepblue.lib.umich.edu/bitstream/2027.42/154178/1/39015100081655.pd
Nonconvergence, Undecidability, and Intractability in Asymptotic Problems
https://deepblue.lib.umich.edu/bitstream/2027.42/154144/1/39015099114582.pd
The potential role of Antarctic krill faecal pellets in efficient carbon export at the marginal ice zone of the South Orkney Islands in spring
Antarctic krill (Euphausia superba) play a central
role in the food web of the Southern Ocean, forming
a link between primary production and large predators.
Krill produce large, faecal pellets (FP) which can form a
large component of mesopelagic particulate organic carbon
(POC) fluxes. However, the patchy distribution of krill
swarms, highly variable pellet composition, and variable
sinking and attenuation rates means that these episodic,
but potentially large, carbon fluxes are difficult to sample
or model. We measured particle flux and type using Marine
Snow Catchers (MSC) in the marginal ice zone near the
South Orkneys, Antarctica. Krill FP were the dominant
component of the POC flux in the upper 200 m (typically
60–85%). FP sinking velocities measured onboard were
highly variable (15–507 m d−
1) but overall high, with
mean equivalent velocities of 172, 267, and 161 m d−
1 at
our three stations. The high numbers of krill FP sinking
through the mesopelagic suggest that krill FP can be transferred
efficiently and/or that rates of krill FP production are
high. We compared our direct MSC-derived estimates of krill FP POC flux (33–154 mg C m−
2 d−
1) and attenuation
to estimates of krill FP production based on previous measurements
of krill density and literature FP egestion rates,
and estimated net krill FP attenuation rates in the upper
mesopelagic. Calculated attenuation rates are sensitive to
krill densities in the overlying water column but suggest
that krill FP could be transferred efficiently through the
upper mesopelagic, and, in agreement with our MSC attenuation
estimates, could make large contributions to bathypelagic
POC fluxes. Our study contrasts with some others
which suggest rapid FP attenuation, highlighting the need
for further work to constrain attenuation rates and assess
how important the contribution of Antarctic krill FP could
be to the Southern Ocean biological carbon pump
A Practical Guide for Managing Interdisciplinary Teams: Lessons Learned from Coupled Natural and Human Systems Research
Interdisciplinary team science is essential to address complex socio-environmental questions, but it also presents unique challenges. The scientific literature identifies best practices for high-level processes in team science, e.g., leadership and team building, but provides less guidance about practical, day-to-day strategies to support teamwork, e.g., translating jargon across disciplines, sharing and transforming data, and coordinating diverse and geographically distributed researchers. This article offers a case study of an interdisciplinary socio-environmental research project to derive insight to support team science implementation. We evaluate the project’s inner workings using a framework derived from the growing body of literature for team science best practices, and derive insights into how best to apply team science principles to interdisciplinary research. We find that two of the most useful areas for proactive planning and coordinated leadership are data management and co-authorship. By providing guidance for project implementation focused on these areas, we contribute a pragmatic, detail-oriented perspective on team science in an effort to support similar projects
Single-probe serial position recall: evidence of modularity for olfactory, visual and auditory short-term memory
The present study examined and compared order memory for a list of sequentially presented odours, unfamiliar-faces and pure-tone. Employing single-probe serial position recall and following a correction for a response bias, qualitatively different serial position functions were observed across stimuli. Participants demonstrated an ability to perform absolute order memory judgments for odours. Furthermore, odours produced an absence of serial position effects, unfamiliar-faces produced both primacy and recency and pure-tones produced recency but not primacy. Such a finding is contrary to the proposal by Ward, Avons and Melling (2005) that the serial position function is task, rather than modality, dependent. In contrast, the observed functions support a modular conceptualisation of short-term memory (e.g. Andrade and Donaldson, 2007; Baddeley and Hitch, 1974), whereby separate modality-specific memorial systems operate. An alternative amodal interpretation is also discussed wherein serial position function disparities are accommodated via differences in the psychological distinctiveness of stimuli (Hay, Smyth, Hitch and Horton, 2007)
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