Change-point models for identifying behavioral transitions in wild animals

Animal behavior can be difficult, time-consuming, and costly to observe in the field directly. Innovative modeling methods, such as hidden Markov models (HMMs), allow researchers to infer unobserved animal behaviors from movement data, and implementations often assume that transitions between states occur multiple times. However, some behavioral shifts of interest, such as parturition, migration initiation, and juvenile dispersal, may only occur once during an observation period, and HMMs may not be the best approach to identify these changes. We present two change-point models for identifying single transitions in movement behavior: a location-based change-point model and a movement metric-based change-point model. We first conducted a simulation study to determine the ability of these models to detect a behavioral transition given different amounts of data and the degree of behavioral shifts. We then applied our models to two ungulate species in central Pennsylvania that were fitted with global positioning system collars and vaginal implant transmitters to test hypotheses related to parturition behavior. We fit these models in a Bayesian framework and directly compared the ability of each model to describe the parturition behavior across species. Our simulation study demonstrated that successful change point estimation using either model was possible given at least 12 h of post-change observations and 15 min fix interval. However, our models received mixed support among deer and elk in Pennsylvania due to behavioral variation between species and among individuals. Our results demonstrate that when the behavior follows the dynamics proposed by the two models, researchers can identify the timing of a behavioral change. Although we refer to detecting parturition events, our results can be applied to any behavior that results in a single change in time.

High Seroprevalence but Low Rate of Isolation of Toxoplasma gondii from Wild Elk (Cervus Canadensis) in Pennsylvania

Toxoplasma gondii infections are prevalent in most warm-blooded animals worldwide. During the 2018 November hunting season in Pennsylvania, fresh (unfixed, not frozen) samples obtained from 99 harvested elk (Cervus canadensis) were tested for T. gondii infection. Antibodies to T. gondii were detected in 69 of 99 (69.7%) elk tested by the modified agglutination test (MAT, 1:25 cut-off). Tongues and hearts from 16 elk with high MAT titers (>1:200) were bioassayed for T. gondii by inoculation in outbred Swiss Webster (SW) and interferon-gamma gene knockout (KO) mice. Viable T. gondii was isolated from tongues of 2 elk with MAT titers of 1:200 and 1:3,200. Toxoplasma gondii from both isolates were successfully propagated in cell culture. Genetic typing on DNA extracted from culture-derived tachyzoites using the PCR restriction fragment length polymorphism with 10 genetic markers (SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico) revealed that both isolates belonged to ToxoDB PCR-RFLP genotype #5 that is widely prevalent in wildlife in the United States. Our results suggest that elk may clear T. gondii organisms from their tissues.

Constituents of Some Species of Beilschmiedia and Endiandra (Lauraceae): New Endiandric Acid and Benzopyran Derivatives Isolated From B. oligandra

On the basis of a preliminary u.v. assay of the dried leaf of nine species of Beilschmiedia and 26 species of Endiandra, several were selected for closer examination. Magnolol (9) was found in B.volckii and (+)-sesamin (10) was isolated from E. xanthocarpa. Endiandric acid B (2) and endiandric acid C (3) were obtained from both E. jonesii and B. tooram, and endiandric acid A (1) was found in B. obtusifolia. The new endiandric acid derivative (1′RS,3′RS,6′SR,7′SR,10′SR,11′ RS,12′RS,13′RS)-2-[6′-(3″,4″-methylenedioxyphenyl) tetracyclo [5.4.2.03,13.010,12]trideca-4′,8′-dien-11′ -yl ]acetic acid (3″,4″-methylenedioxyendiandric acid A) (4) was extracted from B. oligandra which also yielded the new phenolic benzopyran derivative (-)-(E)-2-(4′,8′-dimethylnona-3′,7′-dienyl)-2,8-dimethyl-3,4-dihydro-2H-1-benzopyran-6-ol ( oligandrol ) (12a). Several known hydrocarbon derivatives and terpenoids were isolated from the leaf of E. palmerstonii and E. baillonii, both of which were devoid of endiandric acids.

Heterocyclic-Derivatives of Guanidine. VI. Formation and X-Ray Structure Determination of 2-Dimethylamino-7,8-diphenyl-4,6-dihydropyrrolo[1,2-a]pyrimidine-4,6-dione

The structure N-(2-dimethylamino-4-oxo-7,8-diphenyl-4,6-dihydropyrrolo [l,2-a]pyrimidi n-6-yl-idene)acetamide (3) is proposed for a compound derived from the action of ketene on 2-(2-imino- 3,4-diphenyl-2H-pyrrol-5-yl)-1,1,3-trimethylguanidine (1; R1 = R2 = R3 = Me) on the basis of the crystal structure of its hydrolysis product, the oxo-compound 2-dimethylamino-7,8-diphenyl-4,6-dihydropyrrolo[l,2-a]pyrimidine-4,6-dione (4), the structure of which was determined by X-ray analysis. A lower homologue of (3), N-(2-methylamino-4-oxo-7,8-diphenyl-4,6-dihydro- pyrrolo[l,2-a]pyrimidin-6-ylidene)acetamide (2), and some related compounds are described.

Constituents of Endiandra species. V. 2-[3',5'-Dioxo-4'-phenyl-10'-{(E,E)-5''-phenyl-penta-2'',4''-dien-1''-yl}-2',4',6'-triazatetracyclo[5,4,2,02,6,08,11]tridec12'-en-9'-yl]-acetic acid derived from Endiandra introrsa (Lauraceae)

The structure (9) of the title compound, obtained by treatment of the mother liquor from recrystallization of the naturally occurring acid (6a) with 4-phenyl-1,2,4-triazoline-3,5-dione, has been elucidated by X-ray crystallographic analysis.

Constituents of Endiandra species. III. 4-[(E,E)-5'-Phenylpenta-2',4'-dien-1'-yl]tetra-cyclo[5,4,0,02,5,03,9]undec-10-ene-8-carboxylic acid from Endiandra introrsa (Lauraceae)

The structure (5) is proposed for the title compound on the basis of chemical and spectroscopic evidence and on the X-ray crystal structure of the derivative 4-{(Y-methyl-1'',3''-dioxo-7''-phenyl- 1'',3'',3'',4'',7'',7a''-hexahydroisoindol-4''-yl)methyl}tetracyclo [5,4,0,02,5,O3,9] undec-10-ene-8-carboxylic acid (9c).

Constituents of Endiandra species. II. (E)-4-(6'-Phenyltetracyclo[5,4,2,03,13,010,12]-trideca-4',8'-dien-11'-yl)but-2-enoic acid from Endiandra introrsa (Lauraceae)

The structure (5) of the title compound, a vinylog of endiandric acid, is proposed on the basis of chemical and spectroscopic evidence.

Constituents of Endiandra species. IV. Isolation of 2-(8'-[(E,E)-5'-phenylpenta-2',4''-dien-1''-yl]bicyclo[4,2,0]octa-2',4'-dien-7'-yl)acetic acid, a biogenetically predicted metabolite of Endiandra introrsa (Lauraceae) and its structure determination by means of 1D and 2D N.M.R. spectroscopy

The structure (6a) is proposed for the title compound, on the basis of chemical and spectroscopic data. In particular, a combination of one- and two-dimensional n.m.r. techniques has led to this assignment. Compound (6a) is relatively unstable and its isolation requires a careful extraction process.

Constituents of Endiandra species. I. Endiandric acid, a novel carboxylic acid from Endiandra introrsa (Lauraceae), and a derived lactone

X-ray crystallographic analysis shows that endiandric acid and a derived lactone have the respective structures 2-(6'- phenyltetracyclo[5,4,2,03,13,010,12]trideca-4',8'-dien-11'-yl)acetic acid and 12-phenyl-3-oxapentacyclo[7,5,2,02,6,07,15,013,16]hexadecan-4-one.

N-Acyl Derivatives of Aromatic Ketimines

It has been found that N-acyl aromatic ketimines in general have the property of combining with certain compounds with active hydrogen, such as alcohols, amines, and mercaptans. The reaction takes place at room temperatures and is most pronounced when the acyl group is aliphatic. This property of acyl ketimines can be weakened or prevented by steric hindrance.