Publications by authors named "Jan Schipper"

15 Publications

  • Page 1 of 1

Modelling growth curves of the normal infant's mandible: 3D measurements using computed tomography.

Clin Oral Investig 2021 Apr 16. Epub 2021 Apr 16.

Department of Oral and Maxillofacial Surgery, Erasmus University Medical Centre, Sophia's Children's Hospital, 's Gravendijkwal 230, 3015, CE, Rotterdam, The Netherlands.

Objectives: Data on normal mandibular development in the infant is lacking though essential to understand normal growth patterns and to discriminate abnormal growth. The aim of this study was to provide normal linear measurements of the mandible using computed tomography performed in infants from 0 to 2 years of age.

Material And Methods: 3D voxel software was used to calculate mandibular body length, mandibular ramus length, bicondylar width, bigonial width and the gonial angle. Intra- and inter-rater reliability was assessed for these measurements. They were found to be sufficient for all distances; intra-class correlation coefficients were all above 0.9. Regression analysis for growth modelling was performed.

Results: In this multi-centre retrospective study, 109 CT scans were found eligible that were performed for various reasons (e.g. trauma, craniosynostosis, craniofacial abscesses). Craniosynostosis patients had larger mandibular measurements compared to non-craniosynostosis patients and were therefore excluded. Fifty-one CT scans were analysed.

Conclusions: Analysis showed that the mandible increases more in size vertically (the mandibular ramus) than horizontally (the mandibular body). Most of the mandibular growth occurs in the first 6 months.

Clinical Relevance: These growth models provide insight into normal mandibular development in the first 2 years of life. This reference data facilitates discrimination between normal and abnormal mandibular growth.
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http://dx.doi.org/10.1007/s00784-021-03937-1DOI Listing
April 2021

SNAPSHOT USA 2019: a coordinated national camera trap survey of the United States.

Ecology 2021 06;102(6):e03353

Department of Biology, Francis Marion University, Florence, South Carolina, 29502, USA.

With the accelerating pace of global change, it is imperative that we obtain rapid inventories of the status and distribution of wildlife for ecological inferences and conservation planning. To address this challenge, we launched the SNAPSHOT USA project, a collaborative survey of terrestrial wildlife populations using camera traps across the United States. For our first annual survey, we compiled data across all 50 states during a 14-week period (17 August-24 November of 2019). We sampled wildlife at 1,509 camera trap sites from 110 camera trap arrays covering 12 different ecoregions across four development zones. This effort resulted in 166,036 unique detections of 83 species of mammals and 17 species of birds. All images were processed through the Smithsonian's eMammal camera trap data repository and included an expert review phase to ensure taxonomic accuracy of data, resulting in each picture being reviewed at least twice. The results represent a timely and standardized camera trap survey of the United States. All of the 2019 survey data are made available herein. We are currently repeating surveys in fall 2020, opening up the opportunity to other institutions and cooperators to expand coverage of all the urban-wild gradients and ecophysiographic regions of the country. Future data will be available as the database is updated at eMammal.si.edu/snapshot-usa, as will future data paper submissions. These data will be useful for local and macroecological research including the examination of community assembly, effects of environmental and anthropogenic landscape variables, effects of fragmentation and extinction debt dynamics, as well as species-specific population dynamics and conservation action plans. There are no copyright restrictions; please cite this paper when using the data for publication.
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http://dx.doi.org/10.1002/ecy.3353DOI Listing
June 2021

Ecology of an ocelot population at the northern edge of the species' distribution in northern Sonora, Mexico.

PeerJ 2020 20;8:e8414. Epub 2020 Jan 20.

Friends of Arizona Rivers, Phoenix, AZ, USA.

We used data from eight years of camera trapping at Rancho El Aribabi, a cattle ranch and conservation property in northern Sonora, Mexico, to examine the ecology of the northern-most known breeding population of ocelots (). Ocelots were found mostly in two discrete and disjunct areas: a riverine riparian canyon at just less than 1,000 masl elevation and along arroyos in an oak-mesquite savanna in the Sierra Azul at 1,266-1,406 masl. An ocelot was also detected at a site between those two areas, in an area of a Sonoran desertscrub-foothills thornscrub ecotone at 1,300 masl. At least 18 ocelots, both males and females, were detected during the 2007-2011 and 2014-2018 sampling periods. A female with a kitten was documented in 2011. No individual ocelots were photographed in both areas, which are separated by a minimum of 11.29 km, and no individuals were photographed in both time periods. In a binary logistic regression, key environmental variables predicting ocelot presence were, in order of importance, distance to a paved road, distance to human habitation, proximity to water, and an anthropogenic influences index that was dominated by cattle. Another analysis corroborated the finding regarding ocelot presence and cattle. Contrary to previous studies, ocelot presence was not tied to vegetation cover close to the ground. We present information about the types of habitats and sites ocelots used, short-term movements, daily and seasonal activity patterns, and behavior, including occurrence of different individuals at or near the same site over short periods of time. We discuss ocelot home range, density, and movements, but small sample sizes and study design problems limit the value of estimates derived from our work. Rancho El Aribabi is a private, conservation ranch for which the owners have made voluntary conservation commitments that provide habitat and protection for ocelots and other animals and plants. This northern-most known breeding population is a likely source of ocelots that are periodically detected in southeastern Arizona. Our results should help facilitate conservation of the ocelot in other semi-arid areas of northwestern Mexico and adjacent USA.
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http://dx.doi.org/10.7717/peerj.8414DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6977465PMC
January 2020

Cytokine adsorption is a promising tool in the therapy of hemophagocytic lymphohistiocytosis.

Int J Artif Organs 2019 Nov 26;42(11):658-664. Epub 2019 Jun 26.

Division of Infectious Diseases, Tropical Medicine and Nephrology, Department of Medicine, University of Rostock, Rostock, Germany.

Hemophagocytic lymphohistiocytosis is a life-threatening clinical syndrome caused by severe hypercytokinemia brought on by a highly stimulated but ineffective immune response. Animal studies and case series have demonstrated that a reduction in blood cytokine levels achieved with an extracorporeal adsorption cartridge that contains blood-compatible porous polymer beads (CytoSorb) can effectively attenuate the inflammatory response during sepsis and possibly improve outcomes. We report a case series of two patients in which three episodes of severe hemophagocytic lymphohistiocytosis triggered by infections with herpesviridae were treated successfully with cytokine adsorption. A marked decrease in interleukin-6 plasma levels and a stable or decreasing need of vasopressor therapy were the most significant results of this treatment. Importantly, treatment was safe and well-tolerated, without any adverse events.
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http://dx.doi.org/10.1177/0391398819857444DOI Listing
November 2019

High proportion of cactus species threatened with extinction.

Nat Plants 2015 Oct 5;1:15142. Epub 2015 Oct 5.

Herbarium, University of Arizona, Tucson, Arizona 85721, USA.

A high proportion of plant species is predicted to be threatened with extinction in the near future. However, the threat status of only a small number has been evaluated compared with key animal groups, rendering the magnitude and nature of the risks plants face unclear. Here we report the results of a global species assessment for the largest plant taxon evaluated to date under the International Union for Conservation of Nature (IUCN) Red List Categories and Criteria, the iconic Cactaceae (cacti). We show that cacti are among the most threatened taxonomic groups assessed to date, with 31% of the 1,478 evaluated species threatened, demonstrating the high anthropogenic pressures on biodiversity in arid lands. The distribution of threatened species and the predominant threatening processes and drivers are different to those described for other taxa. The most significant threat processes comprise land conversion to agriculture and aquaculture, collection as biological resources, and residential and commercial development. The dominant drivers of extinction risk are the unscrupulous collection of live plants and seeds for horticultural trade and private ornamental collections, smallholder livestock ranching and smallholder annual agriculture. Our findings demonstrate that global species assessments are readily achievable for major groups of plants with relatively moderate resources, and highlight different conservation priorities and actions to those derived from species assessments of key animal groups.
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http://dx.doi.org/10.1038/nplants.2015.142DOI Listing
October 2015

Baird's tapir density in high elevation forests of the Talamanca region of Costa Rica.

Integr Zool 2012 Dec;7(4):381-388

Sierra to Sea Institute, ProCAT Internacional/Colombia, Las Alturas, Coto Brus, Puntarenas, Costa RicaInstituto de Ecología, Universidad Nacional Autónoma de México (IE-UNAM), Ciudad Universitaria, DF, MexicoCarnivore Ecology Laboratory, Forest and Wildlife Research Center, Mississippi State University, Mississippi, USABig Island Invasive Species Committee, University of Hawaii, Hilo, Hawaii, USAOld Dominion University, Norfolk, Virginia, USA.

Baird's tapir (Tapirus bairdii) is currently endangered throughout its neotropical range with an expected population decline >50% in the next 30 years. We present the first density estimation of Baird's tapir for the Talamanca mountains of Costa Rica, and one of the first for the country. Ten stations with paired cameras were established in Valle del Silencio within Parque Internacional La Amistad (PILA). Seventy-seven tapir pictures of 15 individuals comprising 25 capture-recapture events were analyzed using mark-recapture techniques. The 100% minimum convex polygon of the sampled area was 5.7 km(2) and the effective sampled area using half mean maximum distances moved by tapirs was 7.16 km(2) . We estimated a tapir density of 2.93 individuals/km(2) which represents the highest density reported for this species. Intermountain valleys can represent unique and important habitats for large mammal species. However, the extent of isolation of this population, potentially constrained by steep slopes of the cordillera, remains unknown. Further genetic and movement studies are required to understand meta-population dynamics and connectivity between lowland and highland areas for Baird's tapir conservation in Costa Rica.
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http://dx.doi.org/10.1111/j.1749-4877.2012.00324.xDOI Listing
December 2012

Complete, accurate, mammalian phylogenies aid conservation planning, but not much.

Philos Trans R Soc Lond B Biol Sci 2011 Sep;366(1578):2652-60

Centre d'Ecologie Fonctionnelle et Evolutive, CNRS UMR5175, 1919 Route de Mende, 34293 Montpellier, France.

In the face of unprecedented global biodiversity loss, conservation planning must balance between refining and deepening knowledge versus acting on current information to preserve species and communities. Phylogenetic diversity (PD), a biodiversity measure that takes into account the evolutionary relationships between species, is arguably a more meaningful measure of biodiversity than species diversity, but cannot yet be applied to conservation planning for the majority of taxa for which phylogenetic trees have not yet been developed. Here, we investigate how the quality of data on the taxonomy and/or phylogeny of species affects the results of spatial conservation planning in terms of the representation of overall mammalian PD. The results show that the better the quality of the biodiversity data the better they can serve as a basis for conservation planning. However, decisions based on incomplete data are remarkably robust across different levels of degrading quality concerning the description of new species and the availability of phylogenetic information. Thus, given the level of urgency and the need for action, conservation planning can safely make use of the best available systematic data, limited as these data may be.
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http://dx.doi.org/10.1098/rstb.2011.0104DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3140728PMC
September 2011

Global habitat suitability models of terrestrial mammals.

Philos Trans R Soc Lond B Biol Sci 2011 Sep;366(1578):2633-41

Global Mammal Assessment programme, Department of Biology and Biotechnologies, Sapienza Università di Roma, Viale dell'Università 32, 00185 Rome, Italy.

Detailed large-scale information on mammal distribution has often been lacking, hindering conservation efforts. We used the information from the 2009 IUCN Red List of Threatened Species as a baseline for developing habitat suitability models for 5027 out of 5330 known terrestrial mammal species, based on their habitat relationships. We focused on the following environmental variables: land cover, elevation and hydrological features. Models were developed at 300 m resolution and limited to within species' known geographical ranges. A subset of the models was validated using points of known species occurrence. We conducted a global, fine-scale analysis of patterns of species richness. The richness of mammal species estimated by the overlap of their suitable habitat is on average one-third less than that estimated by the overlap of their geographical ranges. The highest absolute difference is found in tropical and subtropical regions in South America, Africa and Southeast Asia that are not covered by dense forest. The proportion of suitable habitat within mammal geographical ranges correlates with the IUCN Red List category to which they have been assigned, decreasing monotonically from Least Concern to Endangered. These results demonstrate the importance of fine-resolution distribution data for the development of global conservation strategies for mammals.
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http://dx.doi.org/10.1098/rstb.2011.0113DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3140734PMC
September 2011

The changing fates of the world's mammals.

Philos Trans R Soc Lond B Biol Sci 2011 Sep;366(1578):2598-610

IUCN Species Survival Commission, Rue Mauverney 28, 1196 Gland, Switzerland.

A recent complete assessment of the conservation status of 5487 mammal species demonstrated that at least one-fifth are at risk of extinction in the wild. We retrospectively identified genuine changes in extinction risk for mammals between 1996 and 2008 to calculate changes in the International Union for Conservation of Nature (IUCN) Red List Index (RLI). Species-level trends in the conservation status of mammalian diversity reveal that extinction risk in large-bodied species is increasing, and that the rate of deterioration has been most accelerated in the Indomalayan and Australasian realms. Expanding agriculture and hunting have been the main drivers of increased extinction risk in mammals. Site-based protection and management, legislation, and captive-breeding and reintroduction programmes have led to improvements in 24 species. We contextualize these changes, and explain why both deteriorations and improvements may be under-reported. Although this study highlights where conservation actions are leading to improvements, it fails to account for instances where conservation has prevented further deteriorations in the status of the world's mammals. The continued utility of the RLI is dependent on sustained investment to ensure repeated assessments of mammals over time and to facilitate future calculations of the RLI and measurement against global targets.
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http://dx.doi.org/10.1098/rstb.2011.0116DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3140737PMC
September 2011

The impact of conservation on the status of the world's vertebrates.

Science 2010 Dec 26;330(6010):1503-9. Epub 2010 Oct 26.

IUCN SSC Species Survival Commission, c/o United Nations Environment Programme World Conservation Monitoring Centre, 219 Huntingdon Road, Cambridge CB3 0DL, UK.

Using data for 25,780 species categorized on the International Union for Conservation of Nature Red List, we present an assessment of the status of the world's vertebrates. One-fifth of species are classified as Threatened, and we show that this figure is increasing: On average, 52 species of mammals, birds, and amphibians move one category closer to extinction each year. However, this overall pattern conceals the impact of conservation successes, and we show that the rate of deterioration would have been at least one-fifth again as much in the absence of these. Nonetheless, current conservation efforts remain insufficient to offset the main drivers of biodiversity loss in these groups: agricultural expansion, logging, overexploitation, and invasive alien species.
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http://dx.doi.org/10.1126/science.1194442DOI Listing
December 2010

The future of tropical species on a warmer planet.

Conserv Biol 2009 Dec;23(6):1418-26

Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Panama.

Modern global temperature and land cover and projected future temperatures suggest that tropical forest species will be particularly sensitive to global warming. Given a moderate greenhouse gas emissions scenario, fully 75% of the tropical forests present in 2000 will experience mean annual temperatures in 2100 that are greater than the highest mean annual temperature that supports closed-canopy forest today. Temperature-sensitive species might extend their ranges to cool refuges, defined here as areas where temperatures projected for 2100 match 1960s temperatures in the modern range. Distances to such cool refuges are greatest for equatorial species and are particularly large for key tropical forest areas including the Amazon and Congo River Basins, West Africa, and the upper elevations of many tropical mountains. In sum, tropical species are likely to be particularly sensitive to global warming because they are adapted to limited geographic and seasonal variation in temperature, already lived at or near the highest temperatures on Earth before global warming began, and are often isolated from cool refuges. To illustrate these three points, we examined the distributions and habitat associations of all extant mammal species. The distance to the nearest cool refuge exceeded 1000 km for more than 20% of the tropical and less than 4% of the extratropical species with small ranges. The biological impact of global warming is likely to be as severe in the tropics as at temperate and boreal latitudes.
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http://dx.doi.org/10.1111/j.1523-1739.2009.01337.xDOI Listing
December 2009

The status of the world's land and marine mammals: diversity, threat, and knowledge.

Science 2008 Oct;322(5899):225-30

International Union for Conservation of Nature (IUCN) Species Programme, IUCN, 28 Rue Mauverney, 1196 Gland, Switzerland.

Knowledge of mammalian diversity is still surprisingly disparate, both regionally and taxonomically. Here, we present a comprehensive assessment of the conservation status and distribution of the world's mammals. Data, compiled by 1700+ experts, cover all 5487 species, including marine mammals. Global macroecological patterns are very different for land and marine species but suggest common mechanisms driving diversity and endemism across systems. Compared with land species, threat levels are higher among marine mammals, driven by different processes (accidental mortality and pollution, rather than habitat loss), and are spatially distinct (peaking in northern oceans, rather than in Southeast Asia). Marine mammals are also disproportionately poorly known. These data are made freely available to support further scientific developments and conservation action.
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http://dx.doi.org/10.1126/science.1165115DOI Listing
October 2008

Effectiveness of the global protected area network in representing species diversity.

Nature 2004 Apr;428(6983):640-3

Center for Applied Biodiversity Science, Conservation International, Washington, DC 20036, USA.

The Fifth World Parks Congress in Durban, South Africa, announced in September 2003 that the global network of protected areas now covers 11.5% of the planet's land surface. This surpasses the 10% target proposed a decade earlier, at the Caracas Congress, for 9 out of 14 major terrestrial biomes. Such uniform targets based on percentage of area have become deeply embedded into national and international conservation planning. Although politically expedient, the scientific basis and conservation value of these targets have been questioned. In practice, however, little is known of how to set appropriate targets, or of the extent to which the current global protected area network fulfils its goal of protecting biodiversity. Here, we combine five global data sets on the distribution of species and protected areas to provide the first global gap analysis assessing the effectiveness of protected areas in representing species diversity. We show that the global network is far from complete, and demonstrate the inadequacy of uniform--that is, 'one size fits all'--conservation targets.
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http://dx.doi.org/10.1038/nature02422DOI Listing
April 2004

Cataract after total body irradiation and bone marrow transplantation: degree of visual impairment.

Int J Radiat Oncol Biol Phys 2002 Apr;52(5):1375-80

Department of Radiotherapy, University Medical Center Utrecht, The Netherlands.

Purpose: To assess the degree of visual impairment as a result of cataract formation after total body irradiation (TBI) for bone marrow transplantation.

Methods And Materials: The data from 93 patients who received TBI in 1 or 2 fractions as a part of their conditioning regimen for bone marrow transplantation were analyzed with respect to the degree of visual impairment as a result of cataract formation. The probability to develop severe visual impairment (SVI) was determined for all patients, and the degree of visual impairment was assessed for 56 patients with stabilized cataract, using three categories: no, mild, or severe.

Results: For all 93 patients, the probability of developing a cataract causing SVI was 0.44. For allogeneic patients, it was 0.33 without and 0.71 with steroid treatment (p <0.001). All SVI-free probability curves reached a plateau distinct from the cataract-free curves. Apparently, cataracts developing late in the follow-up period rarely cause SVI. Of the patients with stabilized cataract, 32% had no visual impairment, 16% had mild, and 52% severe impairment. No or mild visual impairment was present in 61% of all patients with stable cataract and no steroid treatment compared with only 13% of the patients treated with steroids (p = 0.035).

Conclusion: SVI occurs in only some of the patients (52%) with stable cataract after TBI for bone marrow transplantation in 1 or 2 fractions. Steroid treatment markedly increases the probability of developing visual problems as result of a cataract after TBI.
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http://dx.doi.org/10.1016/s0360-3016(01)02757-2DOI Listing
April 2002
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