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"Jordan, Christopher"
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Effectiveness of Panama as an intercontinental land bridge for large mammals
by
Reyna-Hurtado, Rafael
,
Esser, Helen J.
,
Moreno, Ricardo
in
Bayesian analysis
,
Bayesian statistics
,
Bayesian theory
2020
Habitat fragmentation is a primary driver of wildlife loss, and establishment of biological corridors is a common strategy to mitigate this problem. A flagship example is the Mesoamerican Biological Corridor (MBC), which aims to connect protected forest areas between Mexico and Panama to allow dispersal and gene flow of forest organisms. Because forests across Central America have continued to degrade, the functioning of the MBC has been questioned, but reliable estimates of species occurrence were unavailable. Large mammals are suitable indicators of forest functioning, so we assessed their conservation status across the Isthmus of Panama, the narrowest section of the MBC. We used large-scale camera-trap surveys and hierarchical multispecies occupancy models in a Bayesian framework to estimate the occupancy of 9 medium to large mammals and developed an occupancy-weighted connectivity metric to evaluate species-specific functional connectivity. White-lipped peccary (Tayassu pecari), jaguar (Panthera onca), giant anteater (Myrmecophaga tridactyla), white-tailed deer (Odocoileus virginianus), and tapir (Tapirus bairdii) had low expected occupancy along the MBC in Panama. Puma (Pumaconcolor), red brocket deer (Mazamatemama), ocelot (Leopardus pardalis), and collared peccary (Pecari tajacu), which are more adaptable, had higher occupancy, even in areas with low forest cover near infrastructure. However, the majority of species were subject to ≥ 1 gap that was larger than their known dispersal distances, suggesting poor connectivity along the MBC in Panama. Based on our results, forests in Darien, Donoso–Santa Fe, and La Amistad International Park are critical for survival of large terrestrial mammals in Panama and 2 areas need restoration.
La fragmentación del hábitat es un causante primario de la pérdida de biodiversidad, y el establecimiento de corredores biológicos es una estrategia común para mitigar este problema. El Corredor Biológico Mesoamericano (CBM) es un ejemplo notable que pretende conectar áreas boscosas protegidas entre México y Panamá para permitir la dispersión y flujo genético de organismos del bosque. El funcionamiento del CBM se ha cuestionado debido a que la degradación de los bosques en Centroamérica continúa, pero no se dispone de estimaciones confiables de la ocurrencia de especies. Los mamíferos grandes son indicadores adecuados del funcionamiento de los bosques tropicales Por lo tanto evaluamos su estado de conservación en el Istmo de Panamá, la sección más angosta del CBM. Utilizamos muestreos con cámaras trampa y modelos de ocupación para múltiples especies bajo un modelo Bayesiano para estimar la ocupación de 9 especies de mamíferos medianos a grandes, y desarrollamos una métrica de conectividad ponderada por la ocupación para evaluar la conectividad funcional para cada especie. El puerco de monte (Tayassu pecari), jaguar (Panthera onca), hormiguero gigante (Myrmecophaga tridactyla), venado cola blanca (Oidocoileus virginianus), y tapir (Tapirus bairdii) presentaron una ocupación baja en el CBM en Panamá. El puma (Puma concolor), venado corzo (Mazama temama), ocelote (Leopardus pardalis) y el saino (Pecari tajacu), que son más adaptables, presentaron mayor ocupación, aún en áreas con poca cobertura boscosa, cercanas a infraestructura. Sin embargo, la mayoría de las especies estuvo sujeta a ≥ 1vacío que era mayor que sus distancias de dispersión conocidas, lo que sugiere una conectividad pobre a lo largo del CBM en Panamá. Basados en nuestros resultados, los bosques de Darién, Donoso-Santa Fé y el Parque Internacional La Amistad son críticos para la supervivencia de mamíferos terrestres grandes en Panamá mientras que 2 áreas requieren restauración.
生境破碎化是野生动物数量下降的首要原因,而应对这ー问题的常用策略则是建设生物廊道。ー个典 型的例子是中美洲生物廊道 (Mesoamerican Biological Corridor), 它的建立旨在连接墨西哥和巴拿马之间的 森林保护地,帮助森林中的生物进行扩散和基因交流。然而,由于中美洲范围内的森林在持续退化,中美洲生 物廊道的功能已受到质疑, 但目前仍没有该地区物种分布的可靠评估。大型哺乳动物可以作为森林功能的指 示种,因此, 我们评估了中美洲生物廊道最狭窄的地区一一巴拿马地峡大型哺乳动物的保护状况。我们利用大 规模红外相机调查和贝叶斯框架下的分级多物种占有模型, 估计了九种中大型哺乳动物的分布情况, 并发展出 一个生境占有率加权的连接度指标来评估物种特异的功能连接度。结果显示,白唇西揣 (Tayassu pecan)、美 洲 豹 (Panthera onca) ヽ大 食 蚁 兽 (Myrmecopbaga tridactyla)ヽ白尾鹿 (Odocoileus virginianus) 和中美疆 (Tapirus bairdii) 在巴拿马的中美洲生物廊道一带估计的生境占有率较低。美洲狮 (Puma concolor) 、墨西哥 鹿 (Mazama temama) 、美洲豹猫 (Leopardus pardalis) 和领西揣 (Pecari taiacu) 则适应性更强, 生境占有率 更高,即便是在基础设施附近森林覆盖率较低的地区也是如此。然而,大多数物种都面临着至少ー个超出其已 知扩散距离的问题, 这表明巴拿马的中美洲生物廊道沿线连接度较低。基于以上結果, 达里恩、多诺索 - 圣达菲 和拉米斯塔德国际公园的森林对于巴拿马及其连接的两个需要恢复的地区所生存的大型哺乳动物则显得至关重 要。
Journal Article
Origins of species
\"Human evolution has taken millions of years to get to this stage. But next week, we become something new. Around the world, humanity is undergoing rapid and unpredictable changes, and only three individuals seem to notice that their world is being reborn. But what can they do about it?\"-- Back cover of volume 1.
Spatial Ecological Processes and Local Factors Predict the Distribution and Abundance of Spawning by Steelhead (Oncorhynchus mykiss) across a Complex Riverscape
by
Falke, Jeffrey A.
,
Reeves, Gordon H.
,
McNyset, Kristina M.
in
Abundance
,
Analysis
,
Animal Migration
2013
Processes that influence habitat selection in landscapes involve the interaction of habitat composition and configuration and are particularly important for species with complex life cycles. We assessed the relative influence of landscape spatial processes and local habitat characteristics on patterns in the distribution and abundance of spawning steelhead (Oncorhynchus mykiss), a threatened salmonid fish, across ∼15,000 stream km in the John Day River basin, Oregon, USA. We used hurdle regression and a multi-model information theoretic approach to identify the relative importance of covariates representing key aspects of the steelhead life cycle (e.g., site access, spawning habitat quality, juvenile survival) at two spatial scales: within 2-km long survey reaches (local sites) and ecological neighborhoods (5 km) surrounding the local sites. Based on Akaike's Information Criterion, models that included covariates describing ecological neighborhoods provided the best description of the distribution and abundance of steelhead spawning given the data. Among these covariates, our representation of offspring survival (growing-season-degree-days, °C) had the strongest effect size (7x) relative to other predictors. Predictive performances of model-averaged composite and neighborhood-only models were better than a site-only model based on both occurrence (percentage of sites correctly classified = 0.80±0.03 SD, 0.78±0.02 vs. 0.62±0.05, respectively) and counts (root mean square error = 3.37, 3.93 vs. 5.57, respectively). The importance of both temperature and stream flow for steelhead spawning suggest this species may be highly sensitive to impacts of land and water uses, and to projected climate impacts in the region and that landscape context, complementation, and connectivity will drive how this species responds to future environments.
Journal Article
Mechanical Properties of Low Density Polyethylene
by
Bradley, Jermaine M
,
Jordan, Christopher W
,
Casem, Daniel T
in
Compression zone
,
Deformation
,
Density
2016
The mechanical properties of polymers, particularly as a function of temperature and strain rate, are key for implementation of these materials in design. In this paper, the compressive response of low density polyethylene (LDPE) was investigated across a range of strain rates and temperatures. The mechanical response was found to be temperature and strain rate dependent, showing an increase in stress with increasing strain rate or decreasing temperature. A single linear dependence was observed for flow stress on temperature and log strain rate over the full range of conditions investigated. The temperature and strain rate data were mapped using the method developed by Siviour et al. based on time–temperature superposition using a single mapping parameter indicating that there are no phase transitions over the rates and temperatures investigated. Taylor impact experiments were conducted showing a double deformation zone and yield strength measurements in agreement with compression experiments.
Journal Article
Terrestrial Mammal Occupancy in the Context of Widespread Forest Loss and a Proposed Interoceanic Canal in Nicaragua's Decreasingly Remote South Caribbean Region
by
Dans, Armando J.
,
Jordan, Christopher A.
,
Urquhart, Gerald R.
in
Analysis
,
Animals
,
Beef cattle
2016
Central America is experiencing rapid forest loss and habitat degradation both inside and outside of protected areas. Despite increasing deforestation, the Caribbean region of Nicaragua plays an important role in the survival or extinction of large mammal populations in Central America given that it still retains core areas of habitat for large mammal species. The proposed interoceanic canal project that would bisect the southern half of this Caribbean region represents a new threat that, combined with an advancing agricultural frontier, could affect populations of large mammal species such as jaguars, white-lipped peccaries, and Baird's tapirs. We used occupancy models to examine the relative occupancy probabilities for an assemblage of terrestrial mammals in the south Caribbean region of Nicaragua to identify current core areas for our study species and conduct a preliminary evaluation of the potential impacts of the proposed interoceanic canal. We modeled a community level distribution of eight species with varying levels of sensitivity to human encroachment and a range of habitat associations. Our model results reveal three priority areas for terrestrial mammal conservation in our study area. The mapped predictions show that the only remaining area of suitable habitat for large mammals in the path of the proposed interoceanic canal is a relatively thin strip of forest that runs along the Caribbean Coast. In light of these findings, we propose five recommendations that will help ensure the conservation of this area of the proposed canal route as suitable habitat for our study species.
Journal Article
Dynamics of DHA and EPA supplementation: incorporation into equine plasma, synovial fluid, and surfactant glycerophosphocholines
2021
Introduction
Horses with asthma or osteoarthritis frequently receive ω-3 fatty acid supplements. Docosahexaenoic (DHA; 22:6) and eicosapentaenoic (EPA; 20:5) acids are essential ω-3 fatty acid precursors of anti-inflammatory mediators and components of structural glycerophospholipids (GPL) that act as reservoirs of these fatty acids. Analysis of the incorporation of dietary DHA + EPA into GPL pools in different body compartments has not been undertaken in horses.
Objectives
We undertook a detailed study of dietary supplementation with DHA + EPA in horses and monitored incorporation into DHA- and EPA-containing glycerophosphocholines (GPC) 38:5, 38:6, 40:5, and 40:6 in plasma, synovial fluid (SF), and surfactant.
Methods
Horses (n = 20) were randomly assigned to the supplement or control group and evaluated on days 0, 30, 60, and 90. GPC in plasma, SF, and surfactant were measured by high-resolution mass spectrometry with less than 3 ppm mass error. Validation of DHA and EPA incorporation into these GPC was conducted utilizing MS
2
of the [M + Cl]
−
adducts of GPC.
Results
Dietary supplementation resulted in augmented levels of GPC 38:5, 38:6, 40:5, and 40:6 in all compartments. Maximum incorporation into GPCs was delayed until 60 days. Significant increases in the levels of GPC 38:5, 40:5, and 40:6, containing docosapentaenoic acid (DPA; 22:5), also was noted.
Conclusions
DHA and EPA supplementation results in augmented storage pools of ω-3 essential fatty acids in SF and surfactant GPC. This has the potential to improve the ability of anti-inflammatory mechanisms to resolve inflammatory pathways in these critical compartments involved in arthritis and asthma.
Journal Article
Making the Correct Diagnosis in Thrombotic Microangiopathy: A Narrative Review
2021
Purpose of review:
Thrombotic microangiopathy (TMA) is suspected in patients presenting with thrombocytopenia and evidence of a microangiopathic hemolytic anemia. Patients with TMA can be critically ill, so rapid and accurate identification of the underlying etiology is essential. Due to better insights into pathophysiology and causes of TMA, we can now categorize TMAs as thrombotic thrombocytopenic purpura, postinfectious (mainly Shiga toxin-producing Escherichia coli–induced) hemolytic uremic syndrome (HUS), TMA associated with a coexisting condition, or atypical HUS (aHUS). We recognized an unmet need in the medical community to guide the timely and accurate identification of TMA, the selection of tests to clarify its etiology, and the sequence of steps to initiate treatment.
Sources of information:
Key published studies relevant to the identification, classification, and treatment of TMAs in children or adults. These studies were obtained through literature searches conducted with PubMed or based on the prior knowledge of the authors.
Methods:
This review is the result of a consultation process that reflects the consensus of experts from Canada, the United States, and the United Arab Emirates. The members represent individuals who are clinicians, researchers, and teachers in pediatric and adult medicine from the fields of hematology, nephrology, and laboratory medicine. Authors, through an iterative review process identified and synthesized information from relevant published studies.
Key findings:
Thrombotic thrombocytopenic purpura occurs in the setting of insufficient activity of the von Willebrand factor protease known as ADAMTS13. Shiga toxin-producing Escherichia coli–induced hemolytic uremic syndrome, also known as “typical” HUS, is caused by gastrointestinal infections with bacteria that produce Shiga toxin (initially called verocytotoxin). A variety of clinical conditions or drug exposures can trigger TMA. Finally, aHUS occurs in the setting of inherited or acquired abnormalities in the alternative complement pathway leading to dysregulated complement activation, often following a triggering event such as an infection. It is possible to break the process of etiological diagnosis of TMA into 2 distinct steps. The first covers the initial presentation and diagnostic workup, including the processes of identifying the presence of TMA, appropriate initial tests and referrals, and empiric treatments when appropriate. The second step involves confirming the etiological diagnosis and moving to definitive treatment. For many forms of TMA, the ultimate response to therapies and the outcome of the patient depends on the rapid and accurate identification of the presence of TMA and then a standardized approach to seeking the etiological diagnosis. We present a structured approach to identifying the presence of TMA and steps to identifying the etiology including standardized lab panels. We emphasize the importance of early consultation with appropriate specialists in hematology and nephrology, as well as identification of whether the patient requires plasma exchange. Clinicians should consider appropriate empiric therapies while following the steps we have recommended toward definitive etiologic diagnosis and management of the TMA.
Limitations:
The evidence base for our recommendations consists of small clinical studies, case reports, and case series. They are generally not controlled or randomized and do not lend themselves to a stricter guideline-based methodology or a Grading of Recommendations Assessment, Development and Evaluation (GRADE)-based approach.
Journal Article
Intraoperative discovery of melanosis coli during emergent bowel resection for perforation
by
Chlysta, Walter
,
Christopher, Jordan
,
Hubbard, Grant
in
Case reports
,
Case Reports: Reminder of important clinical lesson
,
Clinical decision making
2022
A patient was taken to the operating room with a presumptive diagnosis of necrotic small bowel and colon. During the procedure, it was noted that she had black mucosa throughout the colon. Several factors suggested viable colonic tissue, and the decision was made to not resect the colon as originally planned. Final pathology of the specimen would later reveal melanosis coli, an ultimately benign diagnosis. Further questioning of the patient found that she had taken a herbal laxative supplement containing several components which are known to cause melanosis coli. We hope that this case report will serve as a reminder to surgeons and clinicians to remember melanosis coli as a clinical entity when confronted with blackened or darkened colonic mucosa. On review of available literature, we identified other cases in which melanosis coli was discovered intraoperatively, and we propose a number of factors to support intraoperative decision making.
Journal Article
Musculoskeletal adverse events in dogs receiving bedinvetmab (Librela)
by
Jordan, Christopher J.
,
Harper, Justin
,
Greene, Mark Irwin
in
accelerated joint destruction
,
Adverse events
,
Algorithms
2025
To conduct a specialist-led disproportionality analysis of musculoskeletal adverse event reports (MSAERs) in dogs treated with bedinvetmab (Librela™) compared to six comparator drugs with the same indication. Furthermore, to report the findings from a subset of dogs whose adverse event (AE) data underwent independent adjudication by an expert panel.
Case-control study and case series analysis.
The European Medicines Agency's EudraVigilance database (2004-2024) and 19 client-owned dogs.
An EBVS
Veterinary Specialist in Surgery individually reviewed all MSAERs to Librela™, Rimadyl
, Metacam
, Previcox
, Onsior
, Galliprant
, and Daxocox
(2004-2024). The primary null hypothesis was that Librela's MSAER rate would not exceed that of comparator drugs by more than 50%. The secondary hypothesis was that MSAER would surge and taper following the launch of new drugs.
The disproportionality analysis did not support the hypotheses. Ligament/tendon injury, polyarthritis, fracture, musculoskeletal neoplasia, and septic arthritis were reported ~9-times more frequently in Librela-treated dogs than the combined total of dogs treated with the comparator drugs. A review of 19 suspected musculoskeletal adverse events (MSAEs) by an 18-member expert panel unanimously concluded a strong suspicion of a causal association between bedinvetmab and accelerated joint destruction.
This study supports recent FDA analyses by demonstrating an increased reporting rate of musculoskeletal adverse events in dogs treated with Librela. Further investigation and close clinical monitoring of treated dogs are warranted.
Our findings should serve as a catalyst for large-scale investigations into bedinvetmab's risks and pharmacovigilance.
Journal Article