465 research outputs found
Benthic foraminifera and gromiids from oxygen-depleted environments â survival strategies, biogeochemistry and trophic interactions
The oceans are losing oxygen (O2), and oxygen minimum zones are
expanding due to climate warming (lower O2 solubility) and
eutrophication related to agriculture. This trend is challenging for most
marine taxa that are not well adapted to O2 depletion. For other taxa
this trend might be advantageous because they can withstand low O2
concentrations or thrive under O2-depleted or even anoxic conditions.
Benthic foraminifera are a group of protists that include taxa with
adaptations to partly extreme environmental conditions. Several species
possess adaptations to O2 depletion that are rare amongst eukaryotes,
and these species might benefit from ongoing ocean deoxygenation. In
addition, since some foraminifera can calcify even under anoxic conditions,
they are important archives for paleoceanographic reconstruction in O2-depleted environments. This paper reviews the current state of knowledge
about foraminifera from low-O2 environments. Recent advances in our
understanding of specific survival strategies of foraminifera to withstand O2
depletion are summarized and discussed. These adaptations include an
anaerobic metabolism, heterotrophic denitrification, symbiosis with
bacteria, kleptoplasty and dormancy and have a strong impact on their
preferred microhabitat in the sediments, especially the ability of some benthic foraminiferal species to denitrify. Benthic foraminifera also differ
regarding their trophic strategies, which has an additional impact on the
selection of their microhabitat. For example, some species are strict
herbivores that feed exclusively on fresh phytodetritus and live close to
the sediment surface, while some species are non-selective detrivores that
occupy intermediate to deep infaunal habitats. There is evidence that
foraminifers have the capacity to undergo phagocytosis, even under anoxia, and some
foraminiferal species which can withstand low-O2 conditions seem to
prey on meiofauna. Also, due to their high abundances in O2-depleted
environments and their metabolic adaptations, benthic foraminifera are key
players in marine nutrient cycling, especially within the marine N and P
cycles. This review summarizes the denitrification rates for the species
that are known to denitrify and the intracellular nitrate concentrations of
the species that are known to intracellularly store nitrate. Finally,
equations are provided that can be used to estimate the intracellular
nutrient storage and denitrification rates of foraminifera and might be
integrated into biogeochemical models.</p
Why the idea of framework propositions cannot contribute to an understanding of delusions
One of the tasks that recent philosophy of psychiatry has taken upon itself is to extend the range of understanding to some of those aspects of psychopathology that Jaspers deemed beyond its limits. Given the fundamental difficulties of offering a literal interpretation of the contents of primary delusions, a number of alternative strategies have been put forward including regarding them as abnormal versions of framework propositions described by Wittgenstein in On Certainty. But although framework propositions share some of the apparent epistemic features of primary delusions, their role in partially constituting the sense of inquiry rules out their role in helping to understand delusions
Secondary left ventricular injury with haemopericardium caused by a rib fracture after blunt chest trauma
Trauma is the third most common cause of death in the West. In the US, approximately 90,000 deaths annually are traumatic in nature and over 75% of casualties from blunt trauma are due to chest injuries. Cardiac injuries from rib fractures following blunt trauma are extremely rare. We report the unusual case of a patient who fell from a height and presented with haemopericardium and haemothorax as a result of left ventricular and lingular lacerations and was sucessfully operated upon
What makes you not a Buddhist? : a preliminary mapping of values
This study sets out to establish which Buddhist values contrasted with or were shared by adolescents from a non-Buddhist population. A survey of attitude toward a variety of Buddhist values was fielded in a sample of 352 non-Buddhist schoolchildren aged between 13 and 15 in London. Buddhist values where attitudes were least positive concerned the worth of being a monk/nun or meditating, offering candles & incense on the Buddhist shrine, friendship on Sangha Day, avoiding drinking alcohol, seeing the world as empty or impermanent and Nirvana as the ultimate peace. Buddhist values most closely shared by non-Buddhists concerned the Law of Karma, calming the mind, respecting those deserving of respect, subjectivity of happiness, welfare work, looking after parents in old age and compassion to cuddly animals. Further significant differences of attitude toward Buddhism were found in partial correlations with the independent variables of sex, age and religious affiliation. Correlation patterns paralleled those previously described in theistic religions. Findings are applied to spiritual, moral, social and cultural development and for the teaching of religious to pupils of no faith adherence. The study recommends that quantitative psychometrics employed to conceptualize Buddhist values by discriminant validity in this study could be extended usefully to other aspects of the study of Buddhism, particularly in quest of validity in the conceptualization of Buddhist identity within specifically Buddhist populations
Unified View of Scaling Laws for River Networks
Scaling laws that describe the structure of river networks are shown to
follow from three simple assumptions. These assumptions are: (1) river networks
are structurally self-similar, (2) single channels are self-affine, and (3)
overland flow into channels occurs over a characteristic distance (drainage
density is uniform). We obtain a complete set of scaling relations connecting
the exponents of these scaling laws and find that only two of these exponents
are independent. We further demonstrate that the two predominant descriptions
of network structure (Tokunaga's law and Horton's laws) are equivalent in the
case of landscapes with uniform drainage density. The results are tested with
data from both real landscapes and a special class of random networks.Comment: 14 pages, 9 figures, 4 tables (converted to Revtex4, PRE ref added
Climate-Biogeochemistry Interactions in the Tropical Ocean: Data collection and legacy
From 2008 through 2019, a comprehensive research project, SFB 754, Climate - Biogeochemistry Interactions in the Tropical Ocean, was funded by the German Research Foundation to investigate the climate-biogeochemistry interactions in the tropical ocean with a particular emphasis on the processes determining the oxygen distribution. During three 4-year long funding phases, a consortium of more than 150 scientists conducted or participated in 34 major research cruises and collected a wealth of physical, biological, chemical, and meteorological data. A common data policy agreed upon at the initiation of the project provided the basis for the open publication of all data. Here we provide an inventory of this unique data set and briefly summarize the various data acquisition and processing methods used
Reproductive Outcomes Following Ectopic Pregnancy: Register-Based Retrospective Cohort Study
Using Scottish national registry data, Sohinee Bhattacharya and colleagues investigate pregnancy outcomes following ectopic pregnancy in comparison to livebirth, miscarriage, or termination in a first pregnancy
Hard and Blind: On Wittgenstein's Genealogical View of Logical Necessity
My main aim is to sketch a certain reading (âgenealogical') of later Wittgenstein's views on logical necessity. Along the way, I engage with the inferentialism currently debated in the literature on the epistemology of deductive logic.publishedVersio
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