2,599 research outputs found

    Camera trap arrays improve detection probability of wildlife: Investigating study design considerations using an empirical dataset.

    Get PDF
    Camera trapping is a standard tool in ecological research and wildlife conservation. Study designs, particularly for small-bodied or cryptic wildlife species often attempt to boost low detection probabilities by using non-random camera placement or baited cameras, which may bias data, or incorrectly estimate detection and occupancy. We investigated the ability of non-baited, multi-camera arrays to increase detection probabilities of wildlife. Study design components were evaluated for their influence on wildlife detectability by iteratively parsing an empirical dataset (1) by different sizes of camera arrays deployed (1-10 cameras), and (2) by total season length (1-365 days). Four species from our dataset that represented a range of body sizes and differing degrees of presumed detectability based on life history traits were investigated: white-tailed deer (Odocoileus virginianus), bobcat (Lynx rufus), raccoon (Procyon lotor), and Virginia opossum (Didelphis virginiana). For all species, increasing from a single camera to a multi-camera array significantly improved detection probability across the range of season lengths and number of study sites evaluated. The use of a two camera array increased survey detection an average of 80% (range 40-128%) from the detection probability of a single camera across the four species. Species that were detected infrequently benefited most from a multiple-camera array, where the addition of up to eight cameras produced significant increases in detectability. However, for species detected at high frequencies, single cameras produced a season-long (i.e, the length of time over which cameras are deployed and actively monitored) detectability greater than 0.75. These results highlight the need for researchers to be critical about camera trap study designs based on their intended target species, as detectability for each focal species responded differently to array size and season length. We suggest that researchers a priori identify target species for which inference will be made, and then design camera trapping studies around the most difficult to detect of those species

    Bibliometric Analysis of Ophthalmic Journals

    Get PDF
    Importance: The primary vehicle for reporting and testing advances in eye care is refereed ophthalmic journals, which can be characterized using targeted bibliometric analyses. Objective: To identify all ophthalmic journals and evaluate citation metrics relating to articles, journals, authors, institutions, and countries published therein. Design and Setting: A bibliometric analysis was undertaken of all ophthalmic journals included in the Scopus database (Elsevier). The search was restricted to all article types published in ophthalmic journals in English from inception through November 18, 2022. After excluding general medical journals, journals published in a language other than English, and spurious titles unrelated to the ophthalmic field, the Scopus database was found to list 335 ophthalmic journal titles that have published 471184 articles, constituting the data set for this analysis. The 20 most highly cited articles were identified. Rank-order lists by article count were assembled for journals, authors, institutions, and countries. Main Outcomes and Measures: An h-index for ophthalmic journal articles was derived from citations and article counts for each constituent of each category. Results: The h-index for ophthalmic journal articles was determined to be 494. The journal with the highest h-index was Ophthalmology (h-index, 297). The journal with the greatest number of articles was American Journal of Ophthalmology (38441 articles). The most highly cited article was by Quigley and Broman, 2006 (5147 citations), concerning the epidemiology of glaucoma. The author with the highest h-index for ophthalmic journal articles was Ronald Klein, MD (h-index, 126), and the most prolific was Carol L. Shields, MD (1400 articles). Johns Hopkins University (h-index, 215) was the institution with the highest h-index for ophthalmic journal articles, and Harvard University was the most prolific (10071 articles). The United States was the nation with the highest h-index for ophthalmic journal articles (h-index, 444) and was the most prolific (180017 articles). Conclusions and Relevance: In this study, the most highly cited articles published in ophthalmic journals were revealed, as well as the leading journals, authors, institutions, and countries. While excluding ophthalmology articles in general medical journals, this investigation affords a means of identifying highly cited authors, institutions, and countries which individuals or institutions can use as a guide regarding contributions to the field.</p

    Endometrial caspase 1 and interleukin-18 expression during the estrous cycle and peri-implantation period of porcine pregnancy and response to early exogenous estrogen administration

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>The role for endometrial secretion of cytokines during the establishment of pregnancy in a number of mammals is well established. The current study determined endometrial expression of caspase 1 (CASP1) and interleukin-18 (IL18) during the estrous cycle and early pregnancy, and following early estrogen administration, which induces conceptus loss during early development in pigs.</p> <p>Methods</p> <p>Gilts were hysterectomized on either D 0, 5, 10, 12, 15 and 18 of the estrous cycle, or D 10, 12, 15 or 18 of pregnancy. The abundance of endometrial CASP1 mRNA was unaffected by day of the estrous cycle, however there was a 6 and 10-fold increase in expression on D 15 and 18 of pregnancy. Endometrial expression of IL18 mRNA increased 5-fold between D 10 to 18 in cyclic and pregnant gilts. Total recoverable IL18 in uterine flushings was greater in pregnant compared to cyclic gilts on D 15 and 18.</p> <p>In the second experiment, mated gilts were treated with either corn oil (CO) or estrogen (E) on D 9 and 10 and hysterectomized on either D 10, 12, 13, 15 or 17 of pregnancy. The current study localizes the presence of CASP1 to the epithelial layer of the endometrium for the first time. Further, a day × treatment interaction was detected for endometrial CASP1 mRNA and protein abundance as E stimulated an earlier increase on D 13 compared to CO gilts. Although IL18 mRNA expression remained unaltered from the E treatment, protein abundance was significantly attenuated on D 15 and 18 in response to E treatment.</p> <p>Conclusions</p> <p>Endometrial expression of CASP1 and IL18 is associated with establishment of pregnancy in pigs. Alteration of CASP1 and IL18 following premature exposure of the uterus to estrogen during early pregnancy may contribute to conceptus loss between Days 15 to 18 of pregnancy.</p

    Analysis and characterization of differential gene expression during rapid trophoblastic elongation in the pig using suppression subtractive hybridization

    Get PDF
    During late peri-implantation development, porcine conceptuses undergo a rapid (2–3 hrs) morphological transformation from a 10 mm sphere to a thin filamentous form greater than 150 mm in length. Elongation of the conceptus is important for establishing adequate placental surface area needed for embryo and fetal survival throughout gestation. Genes involved with triggering this unique transition in conceptus development are not well defined. Objective of the present study was to utilize suppression subtractive hybridization (SSH) to characterize the change in gene expression during conceptus transformation from spherical (8–9 mm) to tubular (15–40 mm) to early filamentous (>150 mm) morphology. Spherical, tubular, and filamentous conceptuses were collected from pregnant gilts and subjected to SSH. Forward and reverse subtractions were performed to identify candidate genes differentially expressed during spherical to tubular and tubular to filamentous transition. A total of 384 transcripts were differentially screened to ensure unique expression. Of the transcripts screened, sequences were obtained for 142 that were confirmed to be differentially expressed among the various morphologies. Gene expression profiles during rapid trophoblastic elongation were generated for selected mRNAs using quantitative real-time PCR. During the transition from tubular to early filamentous conceptuses, s-adenosylhomocysteine hydrolase and heat shock cognate 70 kDa expression were significantly enhanced. A novel unknown gene was isolated and shown to be significantly up-regulated at the onset of rapid trophoblastic elongation and further enhanced in filamentous conceptuses

    Sigma factor n, liaison to an ntrC and rpoS dependent regulatory pathway controlling acid resistance and the LEE in enterohemorrhagic Escherichia coli

    Get PDF
    Enterohemorrhagic Escherichia coli (EHEC) is dependent on acid resistance for gastric passage and low oral infectious dose, and the locus of enterocyte effacement (LEE) for intestinal colonization. Mutation of rpoN, encoding sigma factor N (σ(N)), dramatically alters the growth-phase dependent regulation of both acid resistance and the LEE. This study reports on the determinants of σ(N)-directed acid resistance and LEE expression, and the underlying mechanism attributable to this phenotype. Glutamate-dependent acid resistance (GDAR) in TW14359ΔrpoN correlated with increased expression of the gadX-gadW regulatory circuit during exponential growth, whereas upregulation of arginine-dependent acid resistance (ADAR) genes adiA and adiC in TW14359ΔrpoN did not confer acid resistance by the ADAR mechanism. LEE regulatory (ler), structural (espA and cesT) and effector (tir) genes were downregulated in TW14359ΔrpoN, and mutation of rpoS encoding sigma factor 38 (σ(S)) in TW14359ΔrpoN restored acid resistance and LEE genes to WT levels. Stability, but not the absolute level, of σ(S) was increased in TW14359ΔrpoN; however, increased stability was not solely attributable to the GDAR and LEE expression phenotype. Complementation of TW14359ΔrpoN with a σ(N) allele that binds RNA polymerase (RNAP) but not DNA, did not restore WT levels of σ(S) stability, gadE, ler or GDAR, indicating a dependence on transcription from a σ(N) promoter(s) and not RNAP competition for the phenotype. Among a library of σ(N) enhancer binding protein mutants, only TW14359ΔntrC, inactivated for nitrogen regulatory protein NtrC, phenocopied TW14359ΔrpoN for σ(S) stability, GDAR and ler expression. The results of this study suggest that during exponential growth, NtrC-σ(N) regulate GDAR and LEE expression through downregulation of σ(S) at the post-translational level; likely by altering σ(S) stability or activity. The regulatory interplay between NtrC, other EBPs, and σ(N)-σ(S), represents a mechanism by which EHEC can coordinate GDAR, LEE expression and other cellular functions, with nitrogen availability and physiologic stimuli.Microbiology and Molecular Genetic

    Late Holocene volcanic activity and environmental change in Highland Guatemala

    Get PDF
    We present a record of late Holocene volcanic eruptions with elemental data for a sequence of sampled tephras from Lake Amatitlan in Highland Guatemala. Our tephrochronology is anchored by a Bayesian P_Sequence age-depth model based on multiple AMS radiocarbon dates. We compare our record against a previously published study from the same area to understand the record of volcanism and environmental changes. This work has implications for understanding the effects of climate and other environmental changes that may be related to the emission of volcanic aerosols at local, regional and global scales

    Differential Responses of Progesterone Receptor Membrane Component-1 (Pgrmc1) and the Classical Progesterone Receptor (Pgr) to 17β-Estradiol and Progesterone in Hippocampal Subregions that Support Synaptic Remodeling and Neurogenesis

    Get PDF
    Progesterone (P4) and estradiol (E2) modulate neurogenesis and synaptic remodeling in the hippocampus during the rat estrous cycle and in response to deafferenting lesions, but little is known about the steroidal regulation of hippocampal progesterone receptors associated with these processes. We examined the neuronal expression of progesterone receptor membrane component-1 (Pgrmc1) and the classical progesterone receptor (Pgr), by in situ hybridization and immunohistochemistry. Pgr, a transcription factor, has been associated with synaptic remodeling and other major actions of P4, whereas Pgrmc1 is implicated in P4-dependent proliferation of adult neuroprogenitor cells and with rapid P4 effects on membranes. Ovariectomized adult rats were given E2, P4, or E2+P4 on two schedules: a 4-d model of the rodent estrous cycle and a 30-d model of postmenopausal hormone therapy. Pgr was hormonally responsive only in CA1 pyramidal neurons, and the induction of Pgr by E2 was partly antagonized by P4 only on the 30-d schedule. In CA3 pyramidal and dentate gyrus (DG) neurons, Pgr was largely unresponsive to all hormone treatments. In contrast to Pgr, Pgrmc1 was generally induced by E2 and/or P4 throughout the hippocampus in CA1, CA3, and DG neurons. In neuroprogenitor cells of the DG (immunopositive for bromodeoxyuridine and doublecortin), both Pgrmc1 and Pgr were detected. The differential regulation of hippocampal Pgrmc1 and Pgr by E2 and P4 may guide drug development in hormonal therapy for support of neurogenesis and synaptic regeneration.This work was supported by National Institute on Aging Grants 1PO1 AG026572 (to R.D.B.); Project 4 (to C.E.F. and T.E.M.), Animal Core A (to T.E.M.), and Analytic Core C (to L.Z.)
    • …
    corecore