Restricted Prioritarianism or Competing Claims?

I here settle a recent dispute between two rival theories in distributive ethics: Restricted Prioritarianism and the Competing Claims View. Both views mandate that the distribution of benefits and burdens between individuals should be justifiable to each affected party in a way that depends on the strength of each individual’s separately assessed claim to receive a benefit. However, they disagree about what elements constitute the strength of those individuals’ claims. According to restricted prioritarianism, the strength of a claim is determined in ‘prioritarian’ fashion by both what she stands to gain and her absolute level of well-being, while, according to the competing claims view, the strength of a claim is also partly determined by her level of well-being relative to others with conflicting interests. I argue that, suitably modified, the competing claims view is more plausible than restricted prioritarianism

Spatial variability of Arctic sea ice algae

The most pronounced effects of global climate change have been experienced in the Arctic region. In particular, Arctic sea ice decline and volume loss have emphasized the impeding threat of continued climate change, and have been center stage in the public eye for over a decade. Many of the observed changes in the Arctic are related to the physical system because these parameters, such as sea ice extent and thickness, are more easily observed from space and airborne platforms. The linkage between ecosystem function and its physical environment is clear from all well investigated systems. This undoubtedly means that the observed changes to the physical system have had an equally dramatic impact on the Arctic ecosystem. Our understanding of the Arctic marine ecosystem, however, is severely limited due to the methodological and logistical constraints of monitoring ecological properties. This has caused significant seasonal and geographical knowledge gaps, particularly in the high (> 80ºN) and central Arctic Ocean. Over the past decades a disproportional emphasis has been put on the importance of primary production (PP) and the availability of food in the water column. Observations have indicated an overall increase in Arctic-wide net primary production (NPP) as a result of a thinning and declining sea ice cover, and increasing duration of the phytoplankton growth season. This increased biomass may suggest a corresponding increase in the biomass of consumers and higher trophic levels. This premise, however, neglects the rather important role that the sea ice environment and sea ice algae play in the Arctic food web. The timing, duration and spatial availability of ice algae are drastically different compared to pelagic phytoplankton. Therefore, it is only by first gaining a better understanding of the base of the Arctic food web that we can start to understand the rest of the food web. Throughout this thesis, we aimed to assess how sea ice algae biomass availability and habitat will be affected by continued changes to the sea ice habitat, and what consequences can be expected for the Arctic food web. This was accomplished by developing novel methodologies and approaches to characterize and quantify the spatial variability of sea ice algae-biomass, -primary production and – habitat. Subsequently, we used this toolset to assess the implications of a rapidly changing sea ice habitat in relation to spatial variability of sea ice algae carbon availability and carbon demand by iceassociated organisms. In Chapter 2, we developed a methodological toolbox to process environmental sensor array observations acquired from under-ice profiling platforms (e.g., Remotely Operated Vehicle – ROV, and the Surface and Under-Ice Trawl – SUIT), which included novel mathematical and statistical approaches to representatively capture the spatial variability of sea ice and under-ice physicalbiological properties. We showed that our developed approaches produced observations, which could capture the spatial variability better than traditional point location characterizations of environmental properties. Specifically, the insufficient spatial representativeness of sea ice-algal biomass can cause biases in large-scale ice algal biomass and PP estimates. In Chapter 3, we further developed upon Chapter 2 methodologies by introducing a new approach to estimate primary production on floe-scales (meters to kilometers), further justifying the need for representative ice-algae biomass and PP estimates. We also showed that the sea ice environment and under-ice water properties played an important role in structuring the under-ice community. Furthermore, we indicated that ecological key species of the central Arctic Ocean thrived significantly on carbon synthesized by ice algae. These results highlighted the key role of sea ice as a habitat and as a feeding ground within the Arctic Ocean. In Chapter 4, we aimed to compare the physical-biological properties of multi-year sea ice (MYI) and first-year sea ice (FYI) to provide some insight into how the Arctic will change with the continued replacement of MYI by FYI. We developed and confirmed the hypothesis that thick MYI hummocks do have the potential to host substantial ice algae biomass and identified hummocks as common and permanent features, which represent a reliable habitat for sea ice algae due to the typically thin or absent snow cover. We developed key physical-biological relationships to classify the springtime spatial variability of sea ice algae habitat for both FYI and MYI. We applied this classification to pan- Arctic ice thickness and snow observations, and showed that MYI is substantially under-estimated in terms of suitable habitat. Furthermore, we identified thick sea ice features, such as MYI hummocks and sea ice ridges, as potentially high biomass regions with great ecological value. We also indicated that the thicker sea ice, which remains in late-summer, has reduced melt-induced algal losses. In conclusion, we developed a robust and novel approach to representatively quantify sea ice environmental properties, and sea ice algae biomass and PP at floe-scales. These estimates resulted in more accurate estimates of overall carbon biomass availability and production, which we used to improve the spatial variability of the ice-algae derived carbon budget. We concluded that there was a large mis-match between ice-algal primary produced carbon and ice-algal carbon demand by dominant species. This mis-match was also accompanied by large regional variability. This was expected during our sampling period since production was shutting down. Taking a different approach, we showed that the standing stocks of ice-algal carbon were quite substantial. These results suggest that during late-summer, when primary production shuts down, the remaining ice-algal biomass in high latitude regions may represent a crucial food source to sustain ice associated organisms during the onset of polar night. Altogether, the continued thinning and loss of thicker sea ice features may result in the loss of a reliable carbon supply, in the form of sea ice algae carbon, at key times of the year when other carbon sources are severely limited

Male proneness to verbal display production

The Darwinian theory of sexual selection predicts language-related sex differences in humans originating from and relevant for mate choice. Due to past sex-different selection pressures, it can be assumed that men are more prone to verbal displays than women, both in intrasexual competition and in intersexual selection (i.e., courtship). They should benefit more from high verbal proficiency in mate choice than women. Several hypotheses in the framework of these general evolutionary assumptions were tested using two questionnaires with a total sample of 234 participantsThe Darwinian theory of sexual selection predicts language-related sex differences in humans originating from and relevant for mate choice. Due to past sex-different selection pressures, it can be assumed that men are more prone to verbal displays than women, both in intrasexual competition and in intersexual selection (i.e., courtship). They should benefit more from high verbal proficiency in mate choice than women. Several hypotheses in the framework of these general evolutionary assumptions were tested using two questionnaires with a total sample of 234 participant

A Project View of the Right to Parent

The institution of the family and its importance have recently received considerable attention from political theorists. Leading views maintain that the institution's justification is grounded, at least in part, in the non-instrumental value of the parent–child relationship itself. Such views face the challenge of identifying a specific good in the parent–child relationship that can account for how adults acquire parental rights over a particular child – as opposed to general parental rights, which need not warrant a claim to parent one's biological progeny. I develop a view that meets this challenge. This Project View identifies the pursuit of a parental project as a distinctive non-instrumentally valuable good that provides a justification for the family and whose pursuit is necessary and sufficient for the acquisition of parental rights. This view grounds moral parenthood in a normative relation as opposed to a biological one, supports polyadic forms of parenting, and provides plausible guidance in cases of assisted reproduction

Continuous chlorosulfonation of benzene : I. Phase relations

This work presents liquid-liquid equilibria data on a system suitable for continuous chlorosulfonation of benzene. Complete information is presented for the ternary, chlorosulfonic acid - sulfuric acid - carbon tetrachloride. A partial investigation of the ternary systems, chlorosulfonic acid - sulfuric acid - benzenesulfonyl chloride; chlorosulfonic acid - carbon tetrachloride - benzenesulfonyl chloride; and the quaternary system, carbon tetrachloride - benzenesulfonyl chloride sulfuric acid - chlorosulfonic acid is also presented

Optimal decision making for sperm chemotaxis in the presence of noise

For navigation, microscopic agents such as biological cells rely on noisy sensory input. In cells performing chemotaxis, such noise arises from the stochastic binding of signaling molecules at low concentrations. Using chemotaxis of sperm cells as application example, we address the classic problem of chemotaxis towards a single target. We reveal a fundamental relationship between the speed of chemotactic steering and the strength of directional fluctuations that result from the amplification of noise in the chemical input signal. This relation implies a trade-off between slow, but reliable, and fast, but less reliable, steering. By formulating the problem of optimal navigation in the presence of noise as a Markov decision process, we show that dynamic switching between reliable and fast steering substantially increases the probability to find a target, such as the egg. Intriguingly, this decision making would provide no benefit in the absence of noise. Instead, decision making is most beneficial, if chemical signals are above detection threshold, yet signal-to-noise ratios of gradient measurements are low. This situation generically arises at intermediate distances from a target, where signaling molecules emitted by the target are diluted, thus defining a `noise zone' that cells have to cross. Our work addresses the intermediate case between well-studied perfect chemotaxis at high signal-to-noise ratios close to a target, and random search strategies in the absence of navigation cues, e.g. far away from a target. Our specific results provide a rational for the surprising observation of decision making in recent experiments on sea urchin sperm chemotaxis. The general theory demonstrates how decision making enables chemotactic agents to cope with high levels of noise in gradient measurements by dynamically adjusting the persistence length of a biased persistent random walk.Comment: 9 pages, 5 figure

Surfing along concentration filaments: sperm chemotaxis in physiological shear flows

Many motile biological cells navigate along concentration gradients of signaling molecules: This chemotaxis guides for instance sperm cells from marine invertebrates, which have to find egg cells in the ocean. While chemotaxis has been intensively studied for idealized conditions of rotationally symmetric gradients in still water, natural gradients are usually distorted, e.g., by turbulent flows in the ocean. Recent experiments and direct numerical simulations with sperm cells and bacteria surprisingly suggest the existence of an optimal flow strength at which chemotaxis is more effective than for still water. We use sperm chemotaxis in simple shear flow as a prototypical example to understand the origin of such an optimal flow strength theoretically: We quantify how flow accelerates spreading of signaling molecules released by the egg, but distorts the resulting concentration field into long and thin filaments. The competition between these two effects sets an optimal flow strength that maximizes sperm-egg encounter. We characterize how sperm cells `surf' along concentration filaments, typical for scalar turbulence, revealing a general navigation paradigm in the presence of flow. We compare both simulation and theory with previous experimental results and find good agreement.Comment: manuscript: 6 pages, 4 figures; SI: 11 pages, 8 figure