231 research outputs found
Assessing dental wear in reindeer using geometric morphometrical methods
Assessing dental wear is a useful tool for monitoring the interaction between ungulates and their food resources. However, using a univariate measurement for dental wear, like for instance height of the first molar may not capture the variation in dental wear important for the dental functional morphology. We here demonstrate a method for assessing dental wear for ungulates by using geometric morphometrical methods on 11 mandibles from nine Svalbard reindeer (Rangifer tarandus platyrhynchus). Shape measurements were obtained from a combination of fixed and sliding semi-landmarks, and dental wear was estimated using residual variation of the landmarks. The morphometric measurements obtained showed a good fit when compared to subjective scores of dental wear. We conclude that this method may give a more integrated and robust assessment of dental wear than univariate methods, and suggest it to be used as an alternative or in addition to traditional measurements of dental wear.Abstract in Norwegian / Sammendrag:Vurdering av tannslitasje hos rein ved hjelp av geometrisk morfometriske metoder Vurdering av tannslitasje er en anvendbar metode for å overvåke betydningen av miljøet for livshistorien til hovdyr. Imidlertid vil bruk av et enkelt mål, som for eksempel høyde på første molar, ikke nødvendigvis fange opp variasjonen i tannslitasje som er viktig i forhold til tennenes funksjonelle morfologi. I denne artikkelen viser vi hvordan tannslitasje kan vurderes ved å anvende geometrisk morfometriske metoder på 11 underkjever fra ni Svalbardrein (Rangifer tarandus platyrhynchus). Formen på tannrekka ble målt ved hjelp av en kombinasjon av fikserte og glidende semi-landemerker, hvor tannslitasje ble estimert ved å bruke residual variasjon av landemerkene. De morfometriske målene stemte godt overens med subjektiv vurdering av tannslitasje. Vi konkluderer at denne metoden kan gi en mer integrert og robust vurdering av tannslitasje enn univariate metoder, og foreslår den brukt som et alternativ til eller i tillegg til mer tradisjonelle mål på tannslitasje
Multiple configurations and fluctuating trophic control in the Barents Sea food-web
The Barents Sea is a subarctic shelf sea which has experienced major changes during the past decades. From ecological time-series, three different food-web configurations, reflecting successive shifts of dominance of pelagic fish, demersal fish, and zooplankton, as well as varying trophic control have been identified in the last decades. This covers a relatively short time-period as available ecological time-series are often relatively short. As we lack information for prior time-periods, we use a chance and necessity model to investigate if there are other possible configurations of the Barents Sea food-web than those observed in the ecological time-series, and if this food-web is characterized by a persistent trophic control. We perform food-web simulations using the Non-Deterministic Network Dynamic model (NDND) for the Barents Sea, identify food-web configurations and compare those to historical reconstructions of food-web dynamics. Biomass configurations fall into four major types and three trophic pathways. Reconstructed data match one of the major biomass configurations but is characterized by a different trophic pathway than most of the simulated configurations. The simulated biomass displays fluctuations between bottom-up and top-down trophic control over time rather than persistent trophic control. Our results show that the configurations we have reconstructed are strongly overlapping with our simulated configurations, though they represent only a subset of the possible configurations of the Barents Sea food-web.publishedVersio
ANALISIS PEMAHAMAN KONSEP MATEMATIKA SISWA DENGAN MODEL PEMBELAJARAN PROBLEM BASED LEARNING PADA POKOK BAHASAN SEGITIGA (Study deskriptif di Kelas VII SMP Negeri 2 Plered Kab. Cirebon)
Anggun Maya Sari. NIM 59451058. “Analisis Pemahaman Konsep
Matematika Siswa dengan Model Pembelajaran Problem Based Learning
pada Pokok Bahasan Segitiga”. (Studi Deskriptif di Kelas VII SMP Negeri 2
Plered).
Pembelajaran yang efektif adalah pembelajaran yang menyediakan
kesempatan kepada siswa untuk belajar mandiri, sehingga dalam prosesnya siswa
dapat memperoleh pemahaman dan pengetahuan dengan lebih mendalam. Akan
tetapi proses kegiatan pembelajaran matematika yang berlangsung disekolah, pada
umumnya guru hanya sekedar penyampai informasi tanpa mempertimbangkan
seberapa jauh pemahaman siswa terhadap konsep matematika dari pokok bahasan
segitiga yang disampaikan.
Tujuan penelitian ini adalah 1) mengetahui seberapa besar pemahaman
konsep yang dimiliki peserta didik; 2) mengetahui factor pendukung dan
penghambat peserta didik dalam memahami konsep yang diberikan; 3)
mengetahui deskripsi aktivitas siswa dalam memahami konsep matematika
melalui model pembelajaran Problem Based Learning; 4) mengetahui respon
siswa setelah melaksanakan model pembelajaran Problem Based Learning; 5)
mengetahui sejauhmana pemahaman konsep matematika siswa setelah mengikuti
proses pembelajaran Problem Based Learning.
Penerapan model pembelajaran Problem Based Learning (PBL)
merupakan salah satu model pembelajaran yang dapat memberikan kondisi belajar
aktif kepada siswa. Dengan diterapkannya pembelajaran matematika dengan
model pembelajaran PBL, diharapkan dapat membantu siswa dalam memahami
konsep matematika.
Penelitian ini menggunakan pendekatan kualitatif dan kuantitatif dengan
metode deskriptif. Pengumpulan data menggunakan lembar observasi, pedoman
wawancara, angket dan tes. Informan dalam penelitian ini adalah kelas VII yang
sudah dibentuk kelompok kelas, yaitu VII A, VII D dan VII F. dengan
menggunakan proportionate stratified random sampling, maka dari masingmasing
kelompok kelas didapat 18 siswa sebagai informan penelitian.
Berdasarkan dari hasil wawancara tentang siswa dalam pemahaman konsep
matematika, diperoleh siswa masih kurang dan masih perlu banyak bimbingan.
Aktivitas siswa selama pembelajaran melalui model pembelajaran PBL diperoleh
dari hasil lembar observasi dengan nilai rata-rata dari semua aspek sebesar 54,39%
yang termasuk dalam kategori sedang. Berdasarkan angket respon siswa setelah
dilaksanakan model pembelajaran PBL termasuk dalam kategori baik dengan nilai
rata-rata 76,44%. Pemahaman konsep matematika siswa setelah mengikuti proses
pembelajaran dengan model pembelajaran PBL diperoleh siswa lebih rajin dalam
mencari bahan untuk menyelesaikan soal-soal yang diberikan dan menambah
pemahaman siswa mengenai konsep matematika, meski masih belum 100% benar,
dan hasil tes didapat nilai rata-rata 39% yang termasuk dalam kategori sangat
kurang.
Kata Kunci: Pemahaman konsep matematika, Problem Based Learning, Segitig
Echinococcus multilocularis on Svalbard: introduction of an intermediate host has enabled the local life-cycle
A hierarchical inventory of the world's mountains for global comparative mountain science.
A standardized delineation of the world's mountains has many applications in research, education, and the science-policy interface. Here we provide a new inventory of 8616 mountain ranges developed under the auspices of the Global Mountain Biodiversity Assessment (GMBA). Building on an earlier compilation, the presented geospatial database uses a further advanced and generalized mountain definition and a semi-automated method to enable globally standardized, transparent delineations of mountain ranges worldwide. The inventory is presented on EarthEnv at various hierarchical levels and allows users to select their preferred level of regional aggregation from continents to small subranges according to their needs and the scale of their analyses. The clearly defined, globally consistent and hierarchical nature of the presented mountain inventory offers a standardized resource for referencing and addressing mountains across basic and applied natural as well as social sciences and a range of other uses in science communication and education
Panel-based assessment of ecosystem condition (PAEC) as a knowledge platform for ecosystem-based management of Norwegian Arctic tundra
Analysing diet of small herbivores: the efficiency of DNA barcoding coupled with high-throughput pyrosequencing for deciphering the composition of complex plant mixtures
Background
In order to understand the role of herbivores in trophic webs, it is essential to know what they feed on. Diet analysis is, however, a challenge in many small herbivores with a secretive life style. In this paper, we compare novel (high-throughput pyrosequencing) DNA barcoding technology for plant mixture with traditional microhistological method. We analysed stomach contents of two ecologically important subarctic vole species, Microtus oeconomus and Myodes rufocanus, with the two methods. DNA barcoding was conducted using the P6-loop of the chloroplast trnL (UAA) intron.
Results
Although the identified plant taxa in the diets matched relatively well between the two methods, DNA barcoding gave by far taxonomically more detailed results. Quantitative comparison of results was difficult, mainly due to low taxonomic resolution of the microhistological method, which also in part explained discrepancies between the methods. Other discrepancies were likely due to biases mostly in the microhistological analysis.
Conclusion
We conclude that DNA barcoding opens up for new possibilities in the study of plant-herbivore interactions, giving a detailed and relatively unbiased picture of food utilization of herbivores
General conclusion to the special issue Moving forward on individual heterogeneity
International audienc
Highly overlapping winter diet in two sympatric lemming species revealed by DNA metabarcoding
Sympatric species are expected to minimize competition by partitioning resources, especially
when these are limited. Herbivores inhabiting the High Arctic in winter are a prime example
of a situation where food availability is anticipated to be low, and thus reduced diet
overlap is expected. We present here the first assessment of diet overlap of high arctic lemmings
during winter based on DNA metabarcoding of feces. In contrast to previous analyses
based on microhistology, we found that the diets of both collared (Dicrostonyx
groenlandicus) and brown lemmings (Lemmus trimucronatus) on Bylot Island were dominated
by Salix while mosses, which were significantly consumed only by the brown lemming,
were a relatively minor food item. The most abundant plant taxon, Cassiope
tetragona, which alone composes more than 50% of the available plant biomass, was not
detected in feces and can thus be considered to be non-food. Most plant taxa that were
identified as food items were consumed in proportion to their availability and none were
clearly selected for. The resulting high diet overlap, together with a lack of habitat segregation,
indicates a high potential for resource competition between the two lemming species.
However, Salix is abundant in the winter habitats of lemmings on Bylot Island and the nonSalix
portion of the diets differed between the two species. Also, lemming grazing impact on
vegetation during winter in the study area is negligible. Hence, it seems likely that the high
potential for resource competition predicted between these two species did not translate
into actual competition. This illustrates that even in environments with low primary productivity
food resources do not necessarily generate strong competition among herbivores
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