Understanding the effects of spaceflight on microbial communities is crucial for the success of long-term, manned space missions. Surface-associated bacterial communities, known as biofilms, were ...abundant on the Mir space station and continue to be a challenge on the International Space Station. The health and safety hazards linked to the development of biofilms are of particular concern due to the suppression of immune function observed during spaceflight. While planktonic cultures of microbes have indicated that spaceflight can lead to increases in growth and virulence, the effects of spaceflight on biofilm development and physiology remain unclear. To address this issue, Pseudomonas aeruginosa was cultured during two Space Shuttle Atlantis missions: STS-132 and STS-135, and the biofilms formed during spaceflight were characterized. Spaceflight was observed to increase the number of viable cells, biofilm biomass, and thickness relative to normal gravity controls. Moreover, the biofilms formed during spaceflight exhibited a column-and-canopy structure that has not been observed on Earth. The increase in the amount of biofilms and the formation of the novel architecture during spaceflight were observed to be independent of carbon source and phosphate concentrations in the media. However, flagella-driven motility was shown to be essential for the formation of this biofilm architecture during spaceflight. These findings represent the first evidence that spaceflight affects community-level behaviors of bacteria and highlight the importance of understanding how both harmful and beneficial human-microbe interactions may be altered during spaceflight.
Examines how radical bookstores and similar spaces serve
as launching pads for social movements
How does social change happen? It requires an identified
problem, an impassioned and committed group, a ...catalyst, and a
plan. In this deeply researched consideration of seventy-seven
stores and establishments, Kimberley Kinder argues that activists
also need autonomous space for organizing, and that these spaces
are made, not found. She explores the remarkably enduring presence
of radical bookstores in America and how they provide
infrastructure for organizing-gathering places, retail offerings
that draw new people into what she calls "counterspaces."
Kinder focuses on brick-and-mortar venues where owners approach
their businesses primarily as social movement tools. These may be
bookstores, infoshops, libraries, knowledge cafes, community
centers, publishing collectives, thrift stores, or art
installations. They are run by activist-entrepreneurs who create
centers for organizing and selling books to pay the rent. These
spaces allow radical and contentious ideas to be explored and
percolate through to actual social movements, and serve as
crucibles for activists to challenge capitalism, imperialism, white
privilege, patriarchy, and homophobia. They also exist within a
central paradox: participating in the marketplace creates tensions,
contradictions, and shortfalls. Activist retail does not end
capitalism; collective ownership does not enable a retreat from
civic requirements like zoning; and donations, no matter how
generous, do not offset the enormous power of corporations and
governments.
In this timely and relevant book, Kinder presents a necessary,
novel, and apt analysis of the role these retail spaces play in
radical organizing, one that demonstrates how such durable hubs
manage to persist, often for decades, between the spikes of public
protest.
Presenting the history of space-time physics, from Newton to Einstein, as a philosophical development DiSalle reflects our increasing understanding of the connections between ideas of space and time ...and our physical knowledge. He suggests that philosophy's greatest impact on physics has come about, less by the influence of philosophical hypotheses, than by the philosophical analysis of concepts of space, time and motion, and the roles they play in our assumptions about physical objects and physical measurements. This way of thinking leads to interpretations of the work of Newton and Einstein and the connections between them. It also offers ways of looking at old questions about a priori knowledge, the physical interpretation of mathematics, and the nature of conceptual change. Understanding Space-Time will interest readers in philosophy, history and philosophy of science, and physics, as well as readers interested in the relations between physics and philosophy.
The Modular Multispectral Imaging Array (MMIA) is a suite of optical sensors mounted on an external platform of the European Space Agency’s Columbus Module on the International Space Station. The ...MMIA, together with the Modular X- and Gamma- ray Sensor (MXGS), are the two main instruments forming the Atmosphere-Space Interactions Monitor (ASIM). The primary scientific objectives of the ASIM mission are to study thunderstorm electrical activity such as lightning, Transient Luminous Emissions (TLEs) and Terrestrial Gamma-ray Flashes (TGFs) by observing the associated emissions in the UV, near-infrared, x- and gamma-ray spectral bands. The MMIA includes two cameras imaging in 337 nm and 777.4 nm, at up to 12 frames per second, and three high-speed photometers at 180–230 nm, 337 nm and 777.4 nm, sampling at rates up to 100 kHz. The paper describes the MMIA and the aspects that make it an essential tool for the study of thunderstorms. The mission architecture is described in Neubert et al. (Space Sci. Rev. 215:26,
2019
, this issue) and the MXGS instruments in Østgaard et al. (Space Sci. Rev. 215:23,
2019
, this issue).
The Atmosphere-Space Interactions Monitor (ASIM) is an instrument suite on the International Space Station (ISS) for measurements of lightning, Transient Luminous Events (TLEs) and Terrestrial ...Gamma-ray Flashes (TGFs). Developed in the framework of the European Space Agency (ESA), it was launched April 2, 2018 on the SpaceX CRS-14 flight to the ISS. ASIM was mounted on an external platform of ESA’s Columbus module eleven days later and is planned to take measurements during minimum 3 years. The instruments are an x- and gamma-ray monitor measuring photons from 15 keV to 20 MeV, and an array of three photometers and two cameras measuring in bands at: 180–250 nm, 337 nm and 777.4 nm. Additional objectives that can be addressed with the instruments relate to space physics like aurorae and meteors, and to Earth observation such as dust- and aerosol effects on cloud electrification. The paper describes the scientific objectives of the ASIM mission, the instruments, the mission architecture and the international collaboration supported by the ASIM Science Data Centre. ASIM is the first space mission with a comprehensive suite of instruments designed to measure TLEs and TGFs. Two companion papers describe the instruments in more detail (Østgaard et al. in Space Sci. Rev.,
2019
; Chanrion et al. in Space Sci. Rev.,
2019
).
The book presents a new theory of space: how and why it is a vital component of how societies work. The theory is developed on the basis of a new way of describing and analysing the kinds of spatial ...patterns produced by buildings and towns. The methods are explained so that anyone interested in how towns or buildings are structured and how they work can make use of them. The book also presents a new theory of societies and spatial systems, and what it is about different types of society that leads them to adopt fundamentally different spatial forms. From this general theory, the outline of a 'pathology of modern urbanism' in today's social context is developed.
The space environment is regularly used for experiments addressing astrobiology research goals. The specific conditions prevailing in Earth orbit and beyond, notably the radiative environment ...(photons and energetic particles) and the possibility to conduct long-duration measurements, have been the main motivations for developing experimental concepts to expose chemical or biological samples to outer space, or to use the reentry of a spacecraft on Earth to simulate the fall of a meteorite. This paper represents an overview of past and current research in astrobiology conducted in Earth orbit and beyond, with a special focus on ESA missions such as Biopan, STONE (on Russian FOTON capsules) and EXPOSE facilities (outside the International Space Station). The future of exposure platforms is discussed, notably how they can be improved for better science return, and how to incorporate the use of small satellites such as those built in cubesat format.
A space
X is called
selectively separable (
R-separable) if for every sequence of dense subspaces
(
D
n
:
n
∈
ω
)
one can pick finite (respectively, one-point) subsets
F
n
⊂
D
n
such that
⋃
n
∈
ω
F
n
...is dense in
X. These properties are much stronger than separability, but are equivalent to it in the presence of certain convergence properties. For example, we show that every Hausdorff separable radial space is R-separable and note that neither separable sequential nor separable Whyburn spaces have to be selectively separable. A space is called
d-separable if it has a dense
σ-discrete subspace. We call a space
X D-separable if for every sequence of dense subspaces
(
D
n
:
n
∈
ω
)
one can pick discrete subsets
F
n
⊂
D
n
such that
⋃
n
∈
ω
F
n
is dense in
X. Although
d-separable spaces are often also
D-separable (this is the case, for example, with linearly ordered
d-separable or stratifiable spaces), we offer three examples of countable non-
D-separable spaces. It is known that d-separability is preserved by arbitrary products, and that for every
X, the power
X
d
(
X
)
is d-separable. We show that D-separability is not preserved even by finite products, and that for every infinite
X, the power
X
2
d
(
X
)
is not D-separable. However, for every
X there is a
Y such that
X
×
Y
is D-separable. Finally, we discuss selective and D-separability in the presence of maximality. For example, we show that (assuming
d
=
c
) there exists a maximal regular countable selectively separable space, and that (in ZFC) every maximal countable space is D-separable (while some of those are not selectively separable). However, no maximal space satisfies the natural game-theoretic strengthening of D-separability.
On bounded sets in Ck(X) Ferrando, Juan Carlos
Topology and its applications,
03/2024, Letnik:
344
Journal Article
Recenzirano
Odprti dostop
In this note we study some topological properties of the bounded sets of the locally convex space Ck(X) of all real-valued continuous functions defined on a Tychonoff space X equipped with the ...compact-open topology as well as of the bounded sets of a (DF)-space. We show that, assuming X is a Lindelöf Čech-complete space, if X is scattered then each bounded set in Ck(X) is a Fréchet-Urysohn space under the weak topology. In the opposite direction, if X is pseudocompact and each bounded set in Ck(X) is Fréchet-Urysohn under the weak topology, then X is k-scattered. We also derive a new condition, related to the closed bounded sets, for a (DF)-space to be quasibarrelled, which we apply to the bounded sets of Ck(X). Finally, we get a sort of Krein-like theorem for Ck(X) when X is a Lindelöf Σ-space.
A raíz del giro espacial, las categorías y metáforas para pensar la espacialidad, --a mayoría de ellas provenientes de la geografía humana-, han sido objeto de notable interés por parte de académicos ...de las ciencias humanas y sociales. La escala, es una de las materias y conceptos fundamentales que constituyen a la geografía humana. La escala ofrece un léxico y una realidad discursiva compleja, porosa, y poderosa que conduce a que la escala no pueda ser tratada solamente como una dimensión de la espacialidad (Jonas, 1994). El debate sobre escala se ha dado principalmente en el mundo anglosajón, de ahí que, algunas de las problemáticas asociadas a la cuestión escalar, estén elaboradas desde encuadres analíticos que van desde el marxismo hasta la ontología plana. En el primero, se encuentra el trabajo pionero de Neil Smith, quien planteó que la escala surge con la producción del espacio en el capitalismo y de las discontinuas y contradictorias características del capital (Smith, 2020). A partir de estas nociones materialistas de la escala surgieron toda una serie de trabajos en la década de los noventa cuyo propósito central consistió en argumentar, a partir de diferentes conceptualizaciones y metáforas que la escala es una construcción social (Marston, 2000).
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