The Objectivity of Ordinary Life

Metaethics tends to take for granted a bare Democritean world of atoms and the void, and then worry about how the human world that we all know can possibly be related to it or justified in its terms. I draw on Wittgenstein to show how completely upside-down this picture is, and make some moves towards turning it the right way up again. There may be a use for something like the bare-Democritean model in some of the sciences, but the picture has no standing as the basic objective truth about the world; if anything has that standing, it is ordinary life. I conclude with some thoughts about how the notion of bare, “thin” perception of non-evaluative reality feeds a number of philosophical pathologies, such as behaviourism, and show how a “thicker”, more value-laden, understanding of our perceptions of the world can be therapeutic against them

Phenology and Effects of Dams on the Success of Atlantic Salmon Smolt Migrations in the Penobscot River, Maine

Atlantic salmon Salmo salar populations are diminished throughout their range and high marine mortality is among the drivers of the failure of many stocks to recover. A goal of salmon recovery is to maximize the number of juvenile ‘smolts’ entering the ocean to offset loss therein. Dam removals and changes to hydropower allocation in Maine’s largest river, the Penobscot River, have occurred as part of the Penobscot River Restoration Project (PRRP). These activities, in addition to stocking have the potential to influence the number of smolts reaching the ocean. Telemetry was used to investigate factors influencing initiation of migratory behavior, movement rates, migratory route, and survival through freshwater (FW) before and after changes to the system resulting from the PRRP, and behavior and survival of smolts during estuary migration. Initiation of migration was influenced by smolt development, stocking location and environmental conditions. Smolts with the greatest gill Na+, K+-ATPase activity (physiological development) initiated migration 24 hours sooner than fish with the lowest gill NKA activity. Fish with the greatest cumulative temperature experience (accumulated thermal units: ATU) initiated migration 5 days earlier than those with lowest ATU. Smolts released furthest upstream initiated migration earlier than those released downstream, and movement rate increased 5-fold from upstream to the estuary. Movement rate increased from 2.8 km·h-1 to 5.4 km·h-1 in reaches where dams were removed, and decreased from 2.1 km·h-1 to 0.1 kmh-1 after powerhouse construction. Proportional use of the Stillwater Branch was low (0.12, 95% CI = 0.06 – 0.25), and survival through the dams therein was relatively high (0.99) prior to installation of new powerhouses, decreasing slightly thereafter. Survival at Milford Dam, now the lowermost dam in the main-stem, was low (0.91) prior to increased power generation, whereas survival at Great Works and Veazie Dams was high (0.99 and 0.98) prior to removal. Survival was higher through free-flowing reaches (\u3e 0.99·km-1) than reaches containing dams (c. 0.95·km-1). Survival was reduced at high (\u3e 2000 m3s-1) or low (\u3c300 m3s-1) flow, and was optimal between 12 C and 17 C. Survival increased following dam removal, but survival through those dams was high before removal. The greatest increase in survival (8%) followed turbine shutdown at Howland Dam. Smolts experiencing greatest ATU arrived in the estuary 8 days earlier than those experiencing lowest ATU. Estuary arrival date was 10 days later for fish experiencing high flow than for fish experiencing low flow. Fish released furthest upstream arrived in the estuary 3 days later than those stocked further downstream, but moved 0.5 km·h-1 faster through the estuary. Estuary survival decreased by 40% with increasing number of dams passed (from 2 to 9). Estuary movement rate and survival both peaked in mid-May, and slowed from FW to ocean, likely resulting from tidal influences. Smolts became increasingly surface-oriented during passage from FW to ocean as salt water (SW) became more prevalent. In laboratory experiments, preference for SW by never exceeded 50% during smolt development. Thus, smolts likely select low salinity (i.e. surface) waters during migration through coastal areas. Smolts with low gill NKA activity spent greater time in FW reaches of the estuary than those with high gill NKA activity. However, there was no difference in travel time through SW reaches of the estuary based on gill NKA activity. Fish with the highest gill NKA activity incurred 25% lower mortality through the estuary than fish with lowest gill NKA activity, and survival was lowest where SW was prevalent. These results underscore the importance of physiological preparedness on performance and the delayed effects of dams on survival of smolts during estuary migration, ultimately affecting marine survival estimates

Spin dynamics in high-mobility two-dimensional electron systems

Understanding the spin dynamics in semiconductor heterostructures is highly important for future semiconductor spintronic devices. In high-mobility two-dimensional electron systems (2DES), the spin lifetime strongly depends on the initial degree of spin polarization due to the electron-electron interaction. The Hartree-Fock (HF) term of the Coulomb interaction acts like an effective out-of-plane magnetic field and thus reduces the spin-flip rate. By time-resolved Faraday rotation (TRFR) techniques, we demonstrate that the spin lifetime is increased by an order of magnitude as the initial spin polarization degree is raised from the low-polarization limit to several percent. We perform control experiments to decouple the excitation density in the sample from the spin polarization degree and investigate the interplay of the internal HF field and an external perpendicular magnetic field. The lifetime of spins oriented in the plane of a [001]-grown 2DES is strongly anisotropic if the Rashba and Dresselhaus spin-orbit fields are of the same order of magnitude. This anisotropy, which stems from the interference of the Rashba and the Dresselhaus spin-orbit fields, is highly density-dependent: as the electron density is increased, the kubic Dresselhaus term becomes dominant and reduces the anisotropy.Comment: 13 pages, 6 figure

Birhythmicity, Synchronization, and Turbulence in an Oscillatory System with Nonlocal Inertial Coupling

We consider a model where a population of diffusively coupled limit-cycle oscillators, described by the complex Ginzburg-Landau equation, interacts nonlocally via an inertial field. For sufficiently high intensity of nonlocal inertial coupling, the system exhibits birhythmicity with two oscillation modes at largely different frequencies. Stability of uniform oscillations in the birhythmic region is analyzed by means of the phase dynamics approximation. Numerical simulations show that, depending on its parameters, the system has irregular intermittent regimes with local bursts of synchronization or desynchronization.Comment: 21 pages, many figures. Paper accepted on Physica

In Defence of Modest Doxasticism About Delusions

Here I reply to the main points raised by the commentators on the arguments put forward in my Delusions and Other Irrational Beliefs (OUP, 2009). My response is aimed at defending a modest doxastic account of clinical delusions, and is articulated in three sections. First, I consider the view that delusions are in-between perceptual and doxastic states, defended by Jacob Hohwy and Vivek Rajan, and the view that delusions are failed attempts at believing or not-quite-beliefs, proposed by Eric Schwitzgebel and Maura Tumulty. Then, I address the relationship between the doxastic account of delusions and the role, nature, and prospects of folk psychology, which is discussed by Dominic Murphy, Keith Frankish, and Maura Tumulty in their contributions. In the final remarks, I turn to the continuity thesis and suggest that, although there are important differences between clinical delusions and non-pathological beliefs, these differences cannot be characterised satisfactorily in epistemic terms. \u

Entrainment of randomly coupled oscillator networks by a pacemaker

Entrainment by a pacemaker, representing an element with a higher frequency, is numerically investigated for several classes of random networks which consist of identical phase oscillators. We find that the entrainment frequency window of a network decreases exponentially with its depth, defined as the mean forward distance of the elements from the pacemaker. Effectively, only shallow networks can thus exhibit frequency-locking to the pacemaker. The exponential dependence is also derived analytically as an approximation for large random asymmetric networks.Comment: 4 pages, 3 figures, revtex 4, submitted to Phys. Rev. Let

The role of space, time and sociability in predicting social encounters

Space, time and the social realm are intrinsically linked. While an array of studies have tried to untangle these factors and their influence on human behaviour, hardly any have taken their effects into account at the same time. To disentangle these factors, we try to predict future encounters between students and assess how important social, spatial and temporal features are for prediction. We phrase our problem of predicting future encounters as a link-prediction problem and utilise set of Random Forest predictors for the prediction task. We use data collected by the Copenhagen network study; a study unique in scope and scale and tracks 847 students via mobile phones over the course of a whole academic year. We find that network and social features hold the highest discriminatory power for predicting future encounters

Foci of Schistosomiasis mekongi, Northern Cambodia: II. Distribution of infection and morbidity.

In the province of Kracheh, in Northern Cambodia, a baseline epidemiological survey on Schistosoma mekongi was conducted along the Mekong River between December 1994 and April 1995. The results of household surveys of highly affected villages of the East and the West bank of the river and of school surveys in 20 primary schools are presented. In household surveys 1396 people were examined. An overall prevalence of infection of 49.3% was detected by a single stool examination with the Kato-Katz technique. The overall intensity of infection was 118.2 eggs per gram of stool (epg). There was no difference between the population of the east and west shore of the Mekong for prevalence (P = 0.3) or intensity (P = 0.9) of infection. Severe morbidity was very frequent. Hepatomegaly of the left lobe was detected in 48.7% of the population. Splenomegaly was seen in 26.8% of the study participants. Visible diverted circulation was found in 7.2% of the population, and ascites in 0.1%. Significantly more hepatomegaly (P = 0.001), splenomegaly (P = 0. 001) and patients with diverted circulation (P = 0.001) were present on the west bank of the Mekong. The age group of 10-14 years was most affected. The prevalence of infection in this group was 71.8% and 71.9% in the population of the West and East of the Mekong, respectively. The intensity of infection was 172.4 and 194.2 epg on the West and the East bank, respectively. In the peak age group hepatomegaly reached a prevalence of 88.1% on the west and 82.8% on the east bank. In the 20 schools 2391 children aged 6-16 years were examined. The overall prevalence of infection was 40.0%, ranging from 7.7% to 72.9% per school. The overalls mean intensity of infection was 110.1 epg (range by school: 26.7-187.5 epg). Both prevalence (P = 0.001) and intensity of infection (P = 0.001) were significantly higher in schools on the east side of the Mekong. Hepatomegaly (55.2%), splenomegaly (23.6%), diverted circulation (4. 1%), ascites (0.5%), reported blood (26.7%) and mucus (24.3%) were very frequent. Hepatomegaly (P = 0.001), splenomegaly (P = 0.001), diverted circulation (P = 0.001) and blood in stool (P = 0.001) were significantly more frequent in schools of the east side of the Mekong. Boys suffered more frequently from splenomegaly (P = 0.05), ascites (P = 0.05) and bloody stools (P = 0.004) than girls. No difference in sex was found for the prevalence and intensity of infection and prevalence of hepatomegaly. On the school level prevalence and intensity of infection were highly associated (r = 0. 93, P = 0.0001). The intensity of infection was significantly associated only with the prevalence of hepatomegaly (r = 0.44, P = 0. 05) and blood in stool (r = 0.40, P = 0.02). This comprehensive epidemiological study documents for the first time the public health importance of schistosomiasis mekongi in the Province of Kracheh, Northern Cambodia and points at key epidemiological features of this schistosome species, in particular the high level of morbidity associated with infection

A dam passage performance standard model for American shad

Objectives for recovery of alosines commonly involve improving fish passage at dams during migration. However, a quantitative basis for dam passage performance standards is largely absent. We describe development of a stochastic life-history-based simulation model for American shad, Alosa sapidissima, to estimate effects of dam passage and migratory delay on abundance, spatial distribution of spawning adults, and demographic structuring in space and time. We used the Penobscot River, Maine, USA, as a case study to examine sensitivity of modeled population metrics and probability of achieving specific management goals to inputs. Spawner abundance and percentage of repeat spawners were most sensitive to survival and migration delay at dams, marine survival, and temperature cues for migratory events. Recovery objectives related to abundance and spatial distribution of spawners were achievable under multiple scenarios, but high rates of upstream and downstream passage were necessary. The simulation indicated trade-offs between upstream and downstream passage efficacy whereby increased downstream passage was required to maintain or increase population abundance in conjunction with increased upstream passage. This model provides a quantitative support tool for managers to inform ecologically based decisions about a suite of management scenarios to facilitate recovery and sustainability of diadromous fish populations

On the effectiveness of partial variance reduction in federated learning with heterogeneous data

Data heterogeneity across clients is a key challenge in federated learning. Prior works address this by either aligning client and server models or using control variates to correct client model drift. Although these methods achieve fast convergence in convex or simple non-convex problems, the performance in over-parameterized models such as deep neural networks is lacking. In this paper, we first revisit the widely used FedAvg algorithm in a deep neural network to understand how data heterogeneity influences the gradient updates across the neural network layers. We observe that while the feature extraction layers are learned efficiently by FedAvg, the substantial diversity of the final classification layers across clients impedes the performance. Motivated by this, we propose to correct model drift by variance reduction only on the final layers. We demonstrate that this significantly outperforms existing benchmarks at a similar or lower communication cost. We furthermore provide proof for the convergence rate of our algorithm.Comment: Accepted to CVPR 202