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The leopard Panthera pardus is in range-wide decline, and many populations are highly threatened. Prey depletion is a major cause of global carnivore declines, but the response of leopard survival and density to this threat is unclear: by reducing the density of a dominant competitor (the lion Panthera leo) prey depletion could create both costs and benefits for subordinate competitors. We used capture–recapture models fitted to data from a 7-year camera-trap study in Kafue National Park, Zambia, to obtain baseline estimates of leopard population density and sex-specific apparent survival rates. Kafue is affected by prey depletion, and densities of large herbivores preferred by lions have declined more than the densities of smaller herbivores preferred by leopards. Lion density is consequently low. Estimates of leopard density were comparable to ecosystems with more intensive protection and favourable prey densities. However, our study site is located in an area with good ecological conditions and high levels of protection relative to other portions of the ecosystem, so extrapolating our estimates across the Park or into adjacent Game Management Areas would not be valid. Our results show that leopard density and survival within north-central Kafue remain good despite prey depletion, perhaps because (1) prey depletion has had weaker effects on preferred leopard prey compared to larger prey preferred by lions, and (2) the density of dominant competitors is consequently low. Our results show that the effects of prey depletion can be more complex than uniform decline of all large carnivore species, and warrant further investigation.
Three-dimensional (3D) printing technology is a promising method for bone tissue engineering applications. For enhanced bone regeneration, it is important to have printable ink materials with appealing properties such as construct interconnectivity, mechanical strength, controlled degradation rates, and the presence of bioactive materials. In this respect, we develop a composite ink composed of polycaprolactone (PCL), poly(D,L-lactide-co-glycolide) (PLGA), and hydroxyapatite particles (HAps) and 3D print it into porous constructs. In vitro study revealed that composite constructs had higher mechanical properties, surface roughness, quicker degradation profile, and cellular behaviors compared to PCL counterparts. Furthermore, in vivo results showed that 3D-printed composite constructs had a positive influence on bone regeneration due to the presence of newly formed mineralized bone tissue and blood vessel formation. Therefore, 3D printable ink made of PCL/PLGA/HAp can be a highly useful material for 3D printing of bone tissue constructs.
Organic-rich lake sediments from a trench exposed at the Ziegler Reservoir fossil site near Snowmass Village, Colorado yielded a sequence of 27 insect fossil assemblages, spanning the time interval from about 125 to 77 ka. The assemblages appear to represent MIS 5e, 5c, 5b, and 5a. A total of 99 taxa were identified, mostly beetles. The fossils represent the oldest known Pleistocene insect faunas from high elevation in the Rocky Mountains, and document a series of climatic oscillations from full interglacial to stadial and interstadial environments, accompanied by changes in regional biological communities. The MIS 5e fauna indicates summer temperatures similar to modern values, with winter temperatures 5–7 °C cooler than today. Regional climates cooled somewhat by MIS 5c, and during MIS 5b summer temperatures were 5–6 °C colder than modern values. Summer temperatures recovered to near-modern levels during early MIS 5a, and cooled by 1–2 °C at its end, although winter temperatures were apparently above modern levels. The indication of milder but wetter winters, strengthened by the inclusion of species found today only in the Pacific Northwest region, suggests conditions that may have led to increased snowpack at high elevations in this part of the Rocky Mountains, linked with the onset of MIS 4 glaciation.
Mutual Climatic Range (MCR) analysis was applied to 20 fossil beetle assemblages from 11 sites dating from 14,500 to 400 yr B.P. The fossil sites represent a transect of the Rocky Mountain region from northern Montana to central Colorado. The analyses yielded estimates of mean July and mean January temperatures. The oldest assemblage (14,500 yr B.P.) yielded mean July values of 10–11°C colder than present and mean January values 26–30°C colder than present. Postglacial summer warming was rapid, as indicated by an assemblage dating 13,200 yr B.P., with mean July values only 3–4°C cooler than modern. By 10,000 yr B.P., several assemblages indicate warmer-than-modern mean summer and winter values. By 9000 yr B.P., MCR reconstructions indicate that both summer and winter temperatures were already declining from an early Holocene peak. Mean July values remained above modern levels and mean January values remained below modern levels until 3000 yr B.P. A series of small-scale oscillations followed.
A series of 50 packrat midden assemblages from the Big Bend region of the Chihuahuan Desert, ranging in age from >36,000 yr B.P. to recent, yielded abundant, diverse arthropod faunas. The mesic nature of regional Wisconsin age climates is substantiated by the fauna from 30,000–12,000 yr B.P., especially during the middle Wisconsin (30,000–20,000 yr B.P.). Late Wisconsin faunas contained grassland species which are confined today to cooler, moister regions. Following 12,000 yr B.P., most of these temperate species were replaced either by desert species or by more cosmopolitan taxa, marking the climatic shift from late Wisconsin to postglacial time. Insects indicative of more severe aridity are first recorded at about 6000 yr B.P., but some temperate species persisted until about 2500 yr B.P. After this, only desert dwellers are recorded.
Insect fossils and pollen from late Pleistocene nonmarine peat layers were recovered from cores from the shelf region of the Chukchi Sea at depths of about 50 m below sea level. The peats date to 11,300−11,000 yr B.P. and provide a limiting age for the regional Pleistocene-Holocene marine transgression. The insect fossils are indicative of arctic coastal habitats like those of the Mackenzie Delta region (mean July temperatures = 10.6–14°C) suggesting that 11,000 yr ago the exposed Chukchi Sea shelf had a climate substantially warmer than modern coastal regions of the Alaskan north slope. The pollen spectra are consistent with the age assignment to the Birch Interval (14,000–9000 yr B.P.). The data suggest a meadow-like graminoid tundra with birch shrubs and some willow shrubs growing in sheltered areas.
Previous radiocarbon ages of detrital moss fragments in basal organic sediments of Lake Emma indicated that extensive deglaciation of the San Juan Mountains occurred prior to 14,900 yr B.P. (Carrara et al., 1984). Paleoecological analyses of insect and plant macrofossils from these basal sediments cast doubt on the reliability of the radiocarbon ages. Subsequent accelerator radiocarbon dates of insect fossils and wood fragments indicate an early Holocene age, rather than a late Pleistocene age, for the basal sediments of Lake Emma. These new radiocarbon ages suggest that by at least 10,000 yr B.P. deglaciation of the San Juan Mountains was complete. The insect and plant macrofossils from the basal organic sediments indicate a higher-than-present treeline during the early Holocene. The insect assemblages consisted of about 30% bark beetles, which contrasts markedly with the composition of insects from modern lake sediments and modern specimens collected in the Lake Emma cirque, in which bark beetles comprise only about 3% of the assemblages. In addition, in the fossil assemblages there were a number of flightless insect species (not subject to upslope transport by wind) indicative of coniferous forest environments. These insects were likewise absent in the modern assemblage.
Fossil insects from the late-glacial deposits at the Lamb Spring archaeological site, near Denver, Colorado, are relatively abundant and diverse, providing considerable paleoecological data for the site. The late Pleistocene insect fauna from the site comprises 72 identified taxa, principally beetles. However, the fauna presented an interpretive problem because it contained a mixture of prairie and alpine tundra species. This was initially considered to be the result of a mixing of faunal elements during the climatic transition of late-glacial times, a “no-modern-analog” fauna. Accelerator dating of insect fossil specimens from the two ecological groups helped resolve the paleoecological problem. Fossil specimens of the prairie-associated species were dated at 17,850 ± 550 yr B.P., while specimens of the tundra-associated species yielded an age of 14,500 ± 500 yr B.P. These dates reveal that what appeared to be an ecological mixing was probably a taphonomic problem, wherein full-glacial-age fossils were probably reworked into latest Wisconsin sediments. While both faunal assemblages reflect climatic conditions substantially colder than present, initial results suggest that the full-glacial fauna represents a cold, dry grassland or steppe environment, while the younger fauna suggests moister and more tundra-like conditions.
Thirty-one fossil beetle assemblages from central and eastern Beringia (Alaska, the Yukon Territory, and the now-submerged Bering Land Bridge) have yielded seasonal temperature estimates for the interval 43,550–9250 14C yr before present (yr B.P.). Estimates of the mean temperature of the warmest (TMAX) and coldest (TMIN) months were derived by the Mutual Climatic Range method. Assemblages from northern and western sites show a mid-Wisconsin interstadial TMAX warming from 35,000–30,000 yr B.P.; this warming is less pronounced in assemblages for interior regions. There is little or no beetle evidence for the spread of coniferous forest in eastern Beringia during this interstade, except for in parts of the Yukon Territory. During the last glacial maximum TMAX values were depressed by about 2°–2.5°C in Arctic regions of Beringia, and by about 4°C in the interior; TMIN values were about 8°C colder in both regions. TMAX and TMIN values rose rapidly at northern sites after 12,000 yr B.P. Seasonal temperatures peaked at 11,000 yr B.P., just as the Bering Land Bridge was inundated. This was followed by a sharp climatic cooling between 11,000 and 10,000 yr B.P., the equivalent of a Younger Dryas cooling in eastern Beringia.
In North America, terrestrial records of biodiversity and climate change that span Marine Oxygen Isotope Stage (MIS) 5 are rare. Where found, they provide insight into how the coupling of the ocean–atmosphere system is manifested in biotic and environmental records and how the biosphere responds to climate change. In 2010–2011, construction at Ziegler Reservoir near Snowmass Village, Colorado (USA) revealed a nearly continuous, lacustrine/wetland sedimentary sequence that preserved evidence of past plant communities between ~140 and 55 ka, including all of MIS 5. At an elevation of 2705 m, the Ziegler Reservoir fossil site also contained thousands of well-preserved bones of late Pleistocene megafauna, including mastodons, mammoths, ground sloths, horses, camels, deer, bison, black bear, coyotes, and bighorn sheep. In addition, the site contained more than 26,000 bones from at least 30 species of small animals including salamanders, otters, muskrats, minks, rabbits, beavers, frogs, lizards, snakes, fish, and birds. The combination of macro- and micro-vertebrates, invertebrates, terrestrial and aquatic plant macrofossils, a detailed pollen record, and a robust, directly dated stratigraphic framework shows that high-elevation ecosystems in the Rocky Mountains of Colorado are climatically sensitive and varied dramatically throughout MIS 5.
Ennadai Lake, in the forest-tundra ecotonal region of Keewatin, Northwest Territories, Canada, has been the subject of several paleoecological investigations (palynology, plant macrofossils, fossil soils). This study concerns Holocene insect fossils at Ennadai, a new approach in a region shown to be sensitive to climatic change. The Ennadai I site yielded 53 taxa, representing 13 families of Coleoptera and 7 families of other insects and arachnids, including abundant ants. These fossils range in age from about 6300 to 630 yr B.P. The Ennadai II site produced fossils of 58 taxa, including 13 beetle families and 15 families of other arthropods, ranging in age from 4700 to 870 yr B.P. The insect evidence suggests the presence of trees in the Ennadai region from 6000 to 2200 yr B.P. A conifer pollen decline from 4800 to 4500 yr B.P. at Ennadai has previously been interpreted as an opening up or retreat of forest in response to climatic cooling, but the insect fossils reveal the continued presence of trees during this interval. Both insect assemblages suggest trends of forest retreat and tundra expansion between about 2200 and 1500 yr B.P., presumably due to climatic cooling, with a return of woodland by about 1000 yr B.P.
Background: The hedgehog pathway (Hh) is an important developmental signaling pathway that is commonly dysregulated in brain tumors, most notably in medulloblastomas. To identify novel therapeutic targets within the Hh pathway, we performed the first quantitative proteome-wide evaluation of phosphorylation events resulting from in vitro SHH administration and occurring throughout Hh-driven cerebellar development in vivo. Methods: Multiplexed quantitative mass spectrometry was done using Tandem Mass Tags 10-plex reagents, TiO2 phosphopeptide enrichment and HPLC-MS/MS/MS. Results: Motif analysis of 2-fold changing phosphorylation events suggested casein kinase 2 (CK2) was responsible for mediating 45% of all changes in phosphorylation. Epistasis studies revealed that CK2 activity is necessary for hedgehog signaling and affects terminal signaling components, thereby circumventing challenges of emergence of resistance and a priori resistance that are commonly encountered with existing small molecule inhibitors in medulloblastoma. In vivo, mice harboring MB allografts resistant to current therapies showed near-complete cessation of tumor growth in response to a CK2 inhibitor. Conclusion: Our use of developmental phosphoproteomics revealed casein kinase 2 as a key regulator of hedgehog signaling and therapeutic target in medulloblastoma. Our success establishes a foundation for us, and others, to apply a similar approach in different tumor initiating pathways.
To examine the use of vitamin D supplements during infancy among the participants in an international infant feeding trial.
Information about vitamin D supplementation was collected through a validated FFQ at the age of 2 weeks and monthly between the ages of 1 month and 6 months.
Infants (n 2159) with a biological family member affected by type 1 diabetes and with increased human leucocyte antigen-conferred susceptibility to type 1 diabetes from twelve European countries, the USA, Canada and Australia.
Daily use of vitamin D supplements was common during the first 6 months of life in Northern and Central Europe (>80 % of the infants), with somewhat lower rates observed in Southern Europe (>60 %). In Canada, vitamin D supplementation was more common among exclusively breast-fed than other infants (e.g. 71 % v. 44 % at 6 months of age). Less than 2 % of infants in the USA and Australia received any vitamin D supplementation. Higher gestational age, older maternal age and longer maternal education were study-wide associated with greater use of vitamin D supplements.
Most of the infants received vitamin D supplements during the first 6 months of life in the European countries, whereas in Canada only half and in the USA and Australia very few were given supplementation.
Archaeological remains excavated from the stratified layers of a pre-Columbian borrow pit in the middle of the Cahokia site inform our understanding of how ritual events were related to the social and political foundations of that enormous center. Ordinary and extraordinary refuse, ranging from foods and cooking pots to craft-production debris and sumptuary goods, are associated with a series of large-scale, single-event dumping episodes related to activities that occurred in the principal plaza. Taken as a set, the layers of ceramic, lithic, zooarchaeological, archaeobotanical, osteological, paleoentomological, and sedimentological materials reveal that the construction of Cahokia's Mississippian order was an active, participatory process.
To identify risk factors associated with an outbreak of gram-negative bacteremia (GNB).
A university hospital.
Retrospective case-control study.
Thirty-eight patients developed GNB; 13 patients experienced more than one episode, and eight blood cultures grew more than one gram-negative organism. The most frequently isolated organisms were Stenotrophomonas maltophilia, Klebsiella pneumoniae, Acinetobacter baumannii, and Acinetobacter johnsonii. When the GNB patients (cases) were compared with randomly selected hematology-oncology patients (controls), central venous catheter (CVC) self-care (71% vs 39%; P=.02), and duration of recent hospital stay (median, 15 vs 4 days; P=.01) were identified as risk factors. In a logistic regression model, duration of recent hospital stay was the only risk factor significantly associated with GNB (odds ratio, 1.05; 95% confidence interval, 1.01-1.08; P<.02).
Hematology-oncology patients providing their own CVC care who have recently been hospitalized for more than 2 weeks may be at increased risk of GNB. CVCs should be protected from possible environmental contamination in hematology-oncology patients. Patients providing their own CVC care should undergo continued rigorous education regarding proper CVC care.