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Specimens (n = 508) of eight species of owl (Aves: Strigiformes) collected from 1994 to 2017 in Manitoba, Canada, were weighed and examined for chewing lice (Phthiraptera: Amblycera, Ischnocera). The relationship between host body mass and infestation by 12 species of lice was examined. Host body mass explained 52% (P = 0.03) of the variation in mean intensity of louse infestation among hosts, due primarily to a high abundance of lice on the heaviest owl species. The relationship was due to the mean intensity of lice, and neither species richness nor the prevalence of lice was related to host body mass. For individual louse species, the relationship was due primarily to Kurodaia acadicae Price and Beer, Kurodaia magna Emerson, and an undetermined species of Kurodaia Uchida (Phthiraptera: Menoponidae) (R2 = 0.997), but not the nine Strigiphilus Mjöberg (Phthiraptera: Philopteridae) species (R2 = 0.27). Louse intensity did not increase with body size for individual birds of any of the owl species. Mean intensity is expected to increase in proportion with the size, specifically the surface area, of the host. Why that relationship holds only for one louse genus, and not for the most abundant genus of lice on owls, and weakly compared with other families of birds, has yet to be determined.
Eleven of the 12 species of owls (Aves: Strigidae, Tytonidae) known to occur in Manitoba, Canada, were examined for chewing lice (Phthiraptera: Amblycera, Ischnocera) from 1976 to 2015: barn owl (Tyto alba (Scopoli); Aves: Tytonidae) (n = 2), snowy owl (Bubo scandiacus (Linnaeus); Aves: Strigidae) (n = 77), great horned owl (Bubo virginianus (Gmelin); Aves: Strigidae) (n = 262), great grey owl (Strix nebulosa Förster; Aves: Strigidae) (n = 142), barred owl (Strix varia Barton; Aves: Strigidae) (n = 10), northern hawk owl (Surnia ulula (Linnaeus); Aves: Strigidae) (n = 18), short-eared owl (Asio flammeus (Pontoppidan); Aves: Strigidae) (n = 74), long-eared owl (Asio otus (Linnaeus); Aves: Strigidae) (n = 67), eastern screech owl (Megascops aslo (Linnaeus); Aves: Strigidae) (n = 59), boreal owl (Aegolius funereus (Linnaeus); Aves: Strigidae) (n = 47), and northern saw-whet owl (Aegolius acadicus (Gmelin); Aves: Strigidae) (n = 44), a total of 802 owls. No lice were found infesting barn owl (Tyto alba (Scopoli); Aves: Tytonidae) or eastern screech owl (Megascops asio (Linnaeus); Aves: Strigidae). We collected a total of 113 810 lice of 12 species: Kurodaia Uchida (Phthiraptera: Menoponidae) – three species; and Strigiphilus Mjöberg (Phthiraptera: Philopteridae) – nine species. Overall prevalence of infestation ranged from 10.0% to 88.9%. Mean intensity for total lice ranged from 22.4 to 506.5. Infestation parameters for each louse–host combination are provided; prevalence and mean intensity were not related for louse–host species combinations. Distribution of louse infestations was highly aggregated. In all louse–host combinations but one, either females were more prevalent than males or there was no significant deviation from 50:50. Male Strigiphilus ceblebrachys Denny significantly outnumbered females in snowy owls. There was a tendency for louse species to co-occur on the same host specimen. Where sample sizes for owls were large enough, no seasonal patterns in abundance of lice were detected.
Workforce shortages in psychiatry are common worldwide. The international literature provides insights into factors influencing decisions to train in psychiatry but is predominately survey based. This national cohort study aimed to identify the characteristics of doctors who were most likely to apply to psychiatry training programmes. The sample comprised doctors who entered UK medical schools in 2007/8 and who made first-time specialty training applications in 2015. The association between application to psychiatry and doctors' sociodemographic and educational characteristics was examined using multivariable logistic regression.
Those most likely to apply were White, privately educated older doctors with below average performance at medical school.
To reduce workforce shortages, psychiatry must make itself more attractive to all doctors, especially those from underrepresented groups such as state-educated Black and minority ethnic individuals. Otherwise, national policies to widen participation in the study of medicine by such groups may exacerbate the current recruitment crisis.
This article is an intervention in recent debates about conceptual and normative theorisations of human rights, which have been increasingly characterised by a divide between ‘moral’ and ‘practice-based’/’political’ understandings. My aim is to articulate an alternative, pragmatist understanding of human rights, one that is importantly distinct from the practice-based account with which it might be thought affiliated. In the first part of the article, I reveal the fundamental flaw in the practice-based account of human rights: I argue that it is undermined by the ontological thesis at its heart, which naturalises and reifies political arrangements and institutions that are radically contingent. In the second part, I identify, and outline the attractiveness of, a pragmatist normative account of human rights. In contrast to the practice-based approach, this pragmatist account construes human rights in ideational terms. The pragmatist understanding accepts both the contingency of our practices and the cultural limits to moral justification, while nevertheless retaining a commitment to the enterprise of normative philosophical conversation. I argue, in contrast to prevailing interpretations, that the international theory advanced by John Rawls exemplifies a pragmatist account of human rights and points a way forward for theoretically fruitful but appropriately circumscribed analysis of the concept.
The annual abundance of chewing lice (Phthiraptera) was recorded from 1996 to 2015 in Manitoba, Canada, on two species of woodpeckers (Piciformes: Picidae). Yellow-bellied sapsuckers (Sphyrapicus varius (Linnaeus)) were infested with Menacanthus pici (Denny) (Amblycera: Menoponidae) and Penenirmus auritus (Scopoli) (Ischnocera: Philopteridae); northern flickers (Colaptes auratus (Linnaeus)) were also infested with M. pici, as well as two other Ischnocera, Penenirmus jungens (Kellogg) and Picicola porisma Dalgleish. The mean annual abundance varied from nine to 51 lice per bird for the four species, with prevalence, mean intensity, sex ratio, and nymphs per female also varying among louse species. Menacanthus pici populations on both hosts were unstable: abundance rose over two decades because of increasing prevalence, whereas the abundance of the other three louse species fluctuated around a mean. Population variability was similar for the lice on both hosts, with the metric, PV, ranging from 0.41 to 0.51 on a 0–1 scale, once the effect of the trend in abundance for M. pici had been removed. Although the population dynamics for species of lice on these two woodpeckers were distinct, inter-specific differences in population stability were less pronounced than observed in the few other species of bird lice studied in this way.
Long-term trap catches of seedcorn maggot, Delia platura (Meigen), onion maggot, Delia antiqua (Meigen), and cabbage maggot, Delia radicum (Linnaeus) (Diptera: Anthomyiidae), were used to test the hypothesis that related species have more similar population variability than unrelated ones. Annual abundance was estimated from trap catches for 32 years (two species) or 17 years (one species). Population variability was quantified as PV, a proportion between 0 and 1. The three Delia Robineau-Desvoidy species had PV values of 0.51–0.55 that did not differ significantly. These PV values were found to differ significantly from two unrelated species studied over the same time period in the same habitat, which had PV values of 0.39 and 0.67. The hypothesis that related species have more similar population variabilities than unrelated species in the same habitat was supported. These data strengthen the view that PV is a species-specific trait reflecting the adaptation of life histories to their habitat, with related species showing more similar adaptations than unrelated species. The polyphagous and saprophagous seedcorn maggot had PV similar to the two oligophagous herbivores, casting doubt on the hypothesis that more generalist feeders have less variable populations than more specialised feeders.
Long-term, twice weekly, trap catches of the native carrot weevil, Listronotus oregonensis (LeConte) (Coleoptera: Curculionidae), and the introduced carrot rust fly, Psila rosae (Fabricius) (Diptera: Psilidae), were used to test the hypothesis that native populations fluctuate less from year-to-year than those of introduced species, because the native species has had more time to adapt to temporal variability in its habitat than an introduced species. Variability in annual abundance was estimated for 33 years, and for 11-year or 16–17-year subsets of the 33-year time series. Temporal population variability was quantified as PV, a proportion between 0 and 1. The native carrot weevil had a PV of 0.39, less than that of the introduced carrot rust fly with a PV of 0.67, supporting the hypothesis. Generation 1 for both species showed a decline in PV over three decades consistent with the hypothesis that adaptation to variability in the habitat leads to lower PV. Over 33 years, the carrot weevil developed a second generation with a PV of 0.70, higher than that of the first generation, which is consistent with the hypothesis that adaptation is required to stabilise population dynamics in a new habitat, in this case a new temporally defined habitat.
Specimens of five species of woodpeckers (Piciformes: Picidae) from Manitoba, Canada, were weighed and examined for chewing lice, 1998–2015: downy woodpecker (Picoides pubescens (Linnaeus), n=49), hairy woodpecker (Picoides villosus (Linnaeus), n=23), pileated woodpecker (Dryocopus pileatus (Linnaeus), n=10), northern flicker (Colaptes auratus (Linnaeus), n=170), and yellow-bellied sapsucker (Sphyrapicus varius (Linnaeus), n=239). The relationship between body mass of each host species and infestation by seven species of lice was analysed: Menacanthus pici (Denny) from all host species, Brueelia straminea (Denny) from Picoides Lacépède species, Penenirmus jungens (Kellogg) from northern flicker, Penenirmus auritus (Scopoli) from the other four hosts, Picicola porisma Dalgleish from northern flicker, Picicola snodgrassi (Kellogg) from Picoides species, and Picicola marginatulus (Harrison) from pileated woodpeckers. Mean abundance of lice increased with the mean mass of their host. Neither the species richness of lice nor the prevalence of lice were related to host body mass. Host body mass explained 98% of the variation in mean intensity of louse infestation among hosts. The positive association of mean intensity and body size was also detected for three genera of lice. Louse intensity also increased with body size for individual birds, more so for some species of lice and hosts than others. Body size matters, but the adaptations that allow higher mean intensity on larger host species remain to be determined.
Many aphid species (Hemiptera: Aphididae) that feed on herbaceous crops exhibit a rise and then sudden decline in abundance. Data from a nine-year study of Uroleucon rudbeckiae (Fitch) on Rudbeckia laciniata Linnaeus (Asteraceae) are used to investigate this pattern of seasonal abundance in a non-agricultural aphid. Aphids on a population of tagged and numbered flower stems were counted weekly. Abundance (mean aphids per stem) was partitioned into prevalence (proportion of stems colonised) and mean intensity (aphids per colonised stem), and also considered as the sum of the aphids in individual colonies. Abundance rose in mid-summer to late summer and then declined, peaking between the end of July and mid-September, earlier in years when the peak was higher. Prevalence showed a more uniform and consistent peak than mean intensity. Most of the 949 colonies were small and short-lived, but a small proportion were long-lived and reached 1000 aphids. Large colonies declined more slowly than moderately-sized colonies. Severe weather, shortening day-length, decline in host quality, density-dependent effects on rate of increase, and emigration failed to explain the population decline. An early rise and later decline in immigration, in conjunction with increasing predation through the summer, were consistent with the decline.
Variability is an important characteristic of population dynamics, but the length of the time series required to estimate population variability is poorly understood. To this end, population variability of Macrosiphum euphorbiae (Thomas), Myzus persicae (Sulzer), and Aphis nasturtii (Kaltenbach) (Hemiptera: Aphididae) was investigated. Population variability (measured as PV, a proportion between 0 and 1) was estimated for time series of 3–62 years, giving replicate estimates for time series of 3–20 years that were normally distributed. Mean values for PV were more uniform for a time series of 12 years or longer than for shorter ones. The standard deviation of PV declined to a minimum at 12–15 years, as the length of the time series increased. Discrimination of estimates of PV was reliable for 15-year time series and longer, but not necessarily for shorter ones. Although M. euphorbiae had a relatively low PV, the coefficient of variation of that PV (12.5), was higher than for the other two species (3.5, 4.5). For robust estimates of PV, a time series of 15 years is recommended, because it minimises the standard deviation of PV, and discriminates values of PV that differ by 0.06 on a 0–1 scale.
Three species of woodpeckers (Piciformes: Picidae) in Manitoba, Canada, were examined for chewing lice (Phthiraptera): the resident downy woodpecker (Picoides pubescens (Linnaeus), n=55), and two migrants, yellow-bellied sapsucker (Sphyrapicus varius (Linnaeus), n=316) and northern flicker (Colaptes auratus (Linnaeus), n=225). Six species were collected: Menacanthus pici (Denny) (Amblycera: Menoponidae) from all hosts, and five species of Ischnocera (Philopteridae): Penenirmus auritus (Scopoli) from downy woodpeckers and sapsuckers, Picicola snodgrassi (Kellogg) and Brueelia straminea (Denny) from downy woodpeckers, and Penenirmus jungens (Kellogg) and Picicola porisma Dalgleish from flickers. Adults and nymphs were present on downy woodpeckers all year, and on migrant sapsuckers and flickers from when they arrived until they left, suggesting lice reproduce continuously on their hosts. Prevalence and mean intensities of louse infestations generally decreased from their respective springtime levels to their lowest values during or at the end of the breeding season of their hosts, and then increased in various degrees during the fall. No seasonal pattern in louse sex ratios was observed except on northern flickers, where male to female ratios for two of three species were lowest during the breeding season. Resident and migrant hosts had similar seasonal patterns of infestation by lice.
Five species of woodpeckers (Piciformes: Picidae) in Manitoba, Canada were examined for chewing lice (Phthiraptera: Amblycera and Ischnocera): downy woodpecker (DOWO) (Picoides pubescens (Linnaeus), n=56), hairy woodpecker (HAWO) (Picoides villosus (Linnaeus), n=32), pileated woodpecker (PIWO) (Dryocopus pileatus (Linnaeus), n=12), northern flicker (NOFL) (Colaptes auratus (Linnaeus), n=223), and yellow-bellied sapsucker (YBSA) (Sphyrapicus varius (Linnaeus), n=192). Seven species of lice were collected (total number=40 613): Menacanthus pici (Denny) from all species of woodpeckers, Brueelia straminea (Denny) from both species of Picoides Lacépède, Penenirmus jungens (Kellogg) from northern flicker, Penenirmus auritus (Scopoli) from all species of woodpeckers examined except northern flickers, Picicola porisma Dalgleish from northern flickers, Picicola snodgrassi (Kellogg) from both species of Picoides, and Picicola marginatulus (Harrison) from pileated woodpeckers. Prevalence for total louse infestation ranged from 32.3% to 85.7% (NOFL>YBSA>PIWO>DOWO>HAWO). Mean intensity for total lice ranged from 29.2 to 232.4 (PIWO>NOFL>HAWO>YBSA>DOWO). Infestation parameters for each louse/host combination are provided. Distribution of louse infestations was highly aggregated. In all louse/host combinations, either females were more prevalent than males or there was no significant deviation from 50:50. There was a tendency for louse species to co-occur on the same host specimen.
Thomas Paine is a legendary Anglo-American political icon: a passionate, plain-speaking, relentlessly controversial, revolutionary campaigner, whose writings captured the zeitgeist of the two most significant political events of the eighteenth century, the American and French Revolutions. Though widely acknowledged by historians as one of the most important and influential pamphleteers, rhetoricians, polemicists and political actors of his age, the philosophical content of his writing has nevertheless been almost entirely ignored. This book takes Paine's political philosophy seriously. It explores his views concerning a number of perennial issues in modern political thought including the grounds for, and limits to, political obligation; the nature of representative democracy; the justification for private property ownership; international relations; and the relationship between secular liberalism and religion. It shows that Paine offers a historically and philosophically distinct account of liberalism and a theory of human rights that is a progenitor of our own.