38 research outputs found
The Rossiter-McLaughlin effect in Exoplanet Research
The Rossiter-McLaughlin effect occurs during a planet's transit. It provides
the main means of measuring the sky-projected spin-orbit angle between a
planet's orbital plane, and its host star's equatorial plane. Observing the
Rossiter-McLaughlin effect is now a near routine procedure. It is an important
element in the orbital characterisation of transiting exoplanets. Measurements
of the spin-orbit angle have revealed a surprising diversity, far from the
placid, Kantian and Laplacian ideals, whereby planets form, and remain, on
orbital planes coincident with their star's equator. This chapter will review a
short history of the Rossiter-McLaughlin effect, how it is modelled, and will
summarise the current state of the field before describing other uses for a
spectroscopic transit, and alternative methods of measuring the spin-orbit
angle.Comment: Review to appear as a chapter in the "Handbook of Exoplanets", ed. H.
Deeg & J.A. Belmont
Accommodating Ontologies to Biological Reality—Top-Level Categories of Cumulative-Constitutively Organized Material Entities
BACKGROUND: The Basic Formal Ontology (BFO) is a top-level formal foundational ontology for the biomedical domain. It has been developed with the purpose to serve as an ontologically consistent template for top-level categories of application oriented and domain reference ontologies within the Open Biological and Biomedical Ontologies Foundry (OBO). BFO is important for enabling OBO ontologies to facilitate in reliably communicating and managing data and metadata within and across biomedical databases. Following its intended single inheritance policy, BFO's three top-level categories of material entity (i.e. ‘object’, ‘fiat object part’, ‘object aggregate’) must be exhaustive and mutually disjoint. We have shown elsewhere that for accommodating all types of constitutively organized material entities, BFO must be extended by additional categories of material entity. METHODOLOGY/PRINCIPAL FINDINGS: Unfortunately, most biomedical material entities are cumulative-constitutively organized. We show that even the extended BFO does not exhaustively cover cumulative-constitutively organized material entities. We provide examples from biology and everyday life that demonstrate the necessity for ‘portion of matter’ as another material building block. This implies the necessity for further extending BFO by ‘portion of matter’ as well as three additional categories that possess portions of matter as aggregate components. These extensions are necessary if the basic assumption that all parts that share the same granularity level exhaustively sum to the whole should also apply to cumulative-constitutively organized material entities. By suggesting a notion of granular representation we provide a way to maintain the single inheritance principle when dealing with cumulative-constitutively organized material entities. CONCLUSIONS/SIGNIFICANCE: We suggest to extend BFO to incorporate additional categories of material entity and to rearrange its top-level material entity taxonomy. With these additions and the notion of granular representation, BFO would exhaustively cover all top-level types of material entities that application oriented ontologies may use as templates, while still maintaining the single inheritance principle
The Detectability of Earth's Biosignatures Across Time
Over the past two decades, enormous advances in the detection of exoplanets
have taken place. Currently, we have discovered hundreds of earth-sized
planets, several of them within the habitable zone of their star. In the coming
years, the efforts will concentrate in the characterization of these planets
and their atmospheres to try to detect the presence of biosignatures. However,
even if we discovered a second Earth, it is very unlikely that it would present
a stage of evolution similar to the present-day Earth. Our planet has been far
from static since its formation about 4.5 Ga ago; on the contrary, during this
time, it has undergone multiple changes in it's atmospheric composition, it's
temperature structure, it's continental distribution, and even changes in the
forms of life that inhabit it. All these changes have affected the global
properties of Earth as seen from an astronomical distance. Thus, it is of
interest not only to characterize the observables of the Earth as it is today,
but also at different epochs. Here we review the detectability of the Earth's
globally-averaged properties over time. This includes atmospheric composition
and biosignatures, and surface properties that can be interpreted as sings of
habitability (bioclues). The resulting picture is that truly unambiguous
biosignatures are only detectable for about 1/4 of the Earth's history. The
rest of the time we rely on detectable bioclues that can only establish an
statistical likelihood for the presence of life on a given planet.Comment: To appear in "Handbook of Exoplanets", eds. Deeg, H.J. & Belmonte,
J.A, Springer (2018). arXiv admin note: text overlap with
arXiv:astro-ph/0609398 by other author
Can Internalism and Externalism be Reconciled in a Biological Epistemology of Language?
Doctor can I buy a new kidney? I've heard it isn't forbidden: what is the role of the nephrologist when dealing with a patient who wants to buy a kidney?
Organ trafficking is officially banned in several countries and by the main Nephrology Societies. However, this practice is widespread and is allowed or tolerated in many countries, hence, in the absence of a universal law, the caregiver may be asked for advice, placing him/her in a difficult balance between legal aspects, moral principles and ethical judgments. In spite of the Istanbul declaration, which is a widely shared position statement against organ trafficking, the controversy on mercenary organ donation is still open and some experts argue against taking a negative stance. In the absence of clear evidence showing the clinical disadvantages of mercenary transplantation compared to chronic dialysis, self-determination of the patient (and, with several caveats, of the donor) may conflict with other ethical principles, first of all non-maleficence. The present paper was drawn up with the participation of the students, as part of the ethics course at our medical school. It discusses the situation in which the physician acts as a counselor for the patient in the way of a sort of “reverse” informed consent, in which the patient asks advice regarding a complex personal decision, and includes a peculiar application of the four principles (beneficence, non-maleficence, justice and autonomy) to the donor and recipient parties
