61 research outputs found

    Municipal disorder policing. Dealing with annoyances in public places

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    Contains fulltext : 176463.pdf (publisher's version ) (Open Access)Radboud University, 06 september 2017Promotor : Terpstra, J.B. Co-promotor : Stokkom, B.A.M. van230 p

    Burgers als trustees. Participatie, informele vertegenwoordiging en representativiteit

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    Contains fulltext : 119729.pdf (publisher's version ) (Open Access

    Participatie en vertegenwoordiging. Burgers als trustees

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    Item does not contain fulltext134 p

    The Relationship between Plasma Steroid Hormone Concentrations and the Reproductive Cycle in the Northern Pacific Rattlesnake, \u3cem\u3eCrotalus oreganus\u3c/em\u3e

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    We describe the reproductive cycle of Northern Pacific rattlesnakes (Crotalus oreganus) by quantifying steroid hormone concentrations and observing reproductive behaviors in free-ranging individuals. Additionally, we examined reproductive tissues from museum specimens. Plasma steroid hormone concentrations were quantified for both male and female snakes throughout the active season (March–October). We measured testosterone (T), 5α-dihydrotestosterone (DHT), and corticosterone (B) concentrations in both sexes and 17β-estradiol (E2) and progesterone (P) in females only. We observed reproductive behaviors (e.g., consortship, courtship, and copulation) in the field and measured testis and follicle size in male and female snakes from museum collections to relate steroid hormone concentrations to the timing of reproductive events. Our study revealed that C. oreganus in central California exhibits a bimodal pattern of breeding, with most mating behavior occurring in the spring and some incidences of mating behavior observed in late summer/fall. Each breeding period corresponded with elevated androgen (T or DHT) levels in males. Testes were regressed in the spring when the majority of reproductive behavior was observed in this population, and they reached peak volume in August and September during spermatogenesis. Although we did not detect seasonal variation in female hormone concentrations, some females had high E2 in the spring and fall, coincident with mating and with increased follicle size (indicating vitellogenesis) in museum specimens. Females with high E2 concentrations also had high T and DHT concentrations. Corticosterone concentrations in males and females were not related either to time of year or to concentrations of any other hormones quantified. Progesterone concentrations in females also did not vary seasonally, but this likely reflected sampling bias as females tended to be underground, and thus unobtainable, in summer months when P would be expected to be elevated during gestation. In females, P was positively correlated with T and DHT, and E2 was positively correlated with T

    Nationale politie op lokaal niveau

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    Contains fulltext : 161742pub.pdf (publisher's version ) (Closed access)5 p

    Data from: Extrapair paternity rates vary with latitude and elevation in Emberizid sparrows

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    Mating systems can vary among species and populations and thus influence evolutionary trajectories, ecological traits, and population demography. The siring of offspring by an extrapair male, or extrapair paternity (EPP), is a widespread and varied phenomenon in all vertebrate classes. However, we do not understand all of the factors associated with variation in EPP rates. The breeding synchrony hypothesis suggests that EPP rates should increase with latitude and elevation, whereas the paternal care hypothesis predicts that EPP rates should decrease with elevation. To address these hypotheses, we investigated how population EPP rates vary over elevation and latitude in emberizid sparrows. In comparative analyses including the effects of phylogeny, the relationship between EPP rates and elevation depended on latitude. EPP rates were greater in higher-latitude populations. But within higher-latitude populations, EPP rates decreased with increasing elevation. These findings provide support for both the breeding synchrony and paternal care hypotheses, suggesting that in lower-latitude, higher-elevation populations, the need for male parental care does not outweigh the benefits of seeking extrapair fertilizations in populations with relatively synchronous breeding. In contrast, at higher-latitude, higher-elevation sites, the need for male parental care is greater and might drive lower rates of extrapair mating despite highly synchronous breeding

    Basisteams in de Nationale Politie. Organisatie, taakuitvoering en gebiedsgebonden werk

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    Contains fulltext : 161249.pdf (publisher's version ) (Closed access)189 p
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