294 research outputs found

    Land Cover in a Managed Forest Ecosystem: Mexican Shade Coffee

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    Managed forest ecosystems—agroforestry systems in which crops such as coffee and bananas are planted side-by-side with woody perennials—are being touted as a means of safeguarding forests along with the ecological services they provide. Yet we know little about the determinants of land cover in such systems, information needed to design effective forest conservation policies. This paper presents a spatial regression analysis of land cover in a managed forest ecosystem—a shade coffee region of coastal Mexico. Using high-resolution land cover data derived from aerial photographs along with data on the geophysical and institutional characteristics of the study area, we find that plots in close proximity to urban centers are less likely to be cleared, all other things equal. This result contrasts sharply with the literature on natural forests. In addition, we find that membership in coffee-marketing cooperatives, farm size, and certain soil types are associated with forest cover, while proximity to small town centers is associated with forest clearing.deforestation, managed forest ecosystem, agroforestry, shade-grown coffee, Mexico, spatial econometrics, land cover

    Human gut bacteria tailor extracellular vesicle cargo for the breakdown of diet- and host-derived glycans

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    Extracellular vesicles are produced in all three domains of life, and their biogenesis has common ancient origins in eukaryotes and archaea. Although bacterial vesicles were discovered several decades ago and multiple roles have been attributed to them, no mechanism has been established for vesicles biogenesis in bacteria. For this reason, there is a significant level of skepticism about the biological relevance of bacterial vesicles

    Dust survival rates in clumps passing through the Cas A reverse shock -- II. The impact of magnetic fields

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    Dust grains form in the clumpy ejecta of core-collapse supernovae where they are subject to the reverse shock, which is able to disrupt the clumps and destroy the grains. Important dust destruction processes include thermal and kinetic sputtering as well as fragmentation and grain vaporization. In the present study, we focus on the effect of magnetic fields on the destruction processes. We have performed magneto-hydrodynamical simulations using AstroBEAR to model a shock wave interacting with an ejecta clump. The dust transport and destruction fractions are computed using our post-processing code Paperboats in which the acceleration of grains due to the magnetic field and a procedure that allows partial grain vaporization have been newly implemented. For the oxygen-rich supernova remnant Cassiopeia A we found a significantly lower dust survival rate when magnetic fields are aligned perpendicular to the shock direction compared to the non-magnetic case. For a parallel field alignment, the destruction is also enhanced but at a lower level. The survival fractions depend sensitively on the gas density contrast between the clump and the ambient medium and on the grain sizes. For a low-density contrast of 100100, e.g., 55\,nm silicate grains are completely destroyed while the survival fraction of 1μ1\,\mum grains is 8686\,per cent. For a high-density contrast of 10001000, 9595\,per cent of the 55\,nm grains survive while the survival fraction of 1μ1\,\mum grains is 2626\,per cent. Alternative clump sizes or dust materials (carbon) have non-negligible effects on the survival rate but have a lower impact compared to density contrast, magnetic field strength, and grain size.Comment: Accepted by MNRAS. Author accepted manuscript. Accepted on 23/01/2023. 24 pages, 21 Figure

    Systematic review of the psychometric properties of patient-reported outcome measures for rheumatoid arthritis in the foot and ankle

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    Objective: To identify self-reported outcome measures specific to the foot and ankle in patients with rheumatoid arthritis and to investigate the methodological quality and psychometric properties of these measures. Method: A systematic review focusing on patients with rheumatoid arthritis. Setting: The search was conducted in the PubMed, SCOPUS, CINAHL, PEDro and Google Scholar databases, based on the following inclusion criteria: population (with rheumatoid arthritis) > 18 years; psychometric or clinimetric validation studies of patient-reported outcomes specific to the foot and ankle, in different languages, with no time limit. Two of the present authors independently assessed the quality of the studies located and extracted the relevant data. Terwee’s criteria and the COSMIN checklist were employed to ensure adequate methodological quality. Results: Of the initial 431 studies considered, 14 met the inclusion criteria, representing 7,793 patients (56.8 years). These instruments were grouped into three dimensions (pain, perceived health status and quality of life and disability). The time to complete any of the PROMs varies around 15 minutes. PROMs criterias with the worst scores by COSMIN, 92.85% and 85.71% were criterion validity, measurement error, internal consistency and responsiveness. 28.57% of PROMs were compared with the measurement properties. Conclusion: the Self-Reported Foot and Ankle Score achieved the highest number of positive criteria (according to Terwee and COSMIN), and is currently the most appropriate for patients with Rheumatoid arthritis

    Dual membrane-spanning anti-sigma factors regulate vesiculation in Bacteroides thetaiotaomicron

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    Bacteroidota are abundant members of the human gut microbiota that shape the enteric landscape by modulating host immunity and degrading dietary- and host-derived glycans. These processes are mediated in part b

    Теоретико-методологічні основи розуміння механізму правового регулювання

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    Метою цієї статті є аналіз напрямів наукових досліджень, що у своїй єдності формують теорію механізму правового регулювання (МПР), розкриття теоретикометодологічних проблем, які мають місце при осмисленні МПР, визначення та систематизація методологічних підходів до розуміння МПР

    From total destruction to complete survival: dust processing at different evolutionary stages in the supernova remnant Cassiopeia A

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    The expanding ejecta of supernova remnants (SNRs) are believed to form dust in dense clumps of gas. Before the dust can be expelled into the interstellar medium and contribute to the interstellar dust budget, it has to survive the reverse shock that is generated through the interaction of the preceding supernova blast wave with the surrounding medium. The conditions under which the reverse shock hits the clumps change with remnant age and define the dust survival rate. To study the dust destruction in the SNR Cassiopeia A, we conduct magnetohydrodynamical simulations of the evolution of a supernova blast wave and of the reverse shock. In a second step, we use these evolving conditions to model clumps that are disrupted by the reverse shock at different remnant ages. Finally, we compute the amount of dust that is destroyed by the impact of the reverse shock. We find that most of the dust in the SNR is hit by the reverse shock within the first 350 yr after the SN explosion. While the dust destruction in the first 200 yr is almost complete, we expect greater dust survival rates at later times and almost total survival for clumps that are first impacted at ages beyond 1000 yr. Integrated over the entire evolution of the SNR, the dust mass shows the lowest survival fraction (17 per cent) for the smallest grains (1 nm) and the highest survival fraction (28 per cent) for the largest grains (1000 nm)

    Quantification of the Relative Age Effect in Three Indices of Physical Performance

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    The relative age effect (RAE) describes the relationship between an individual's birth month and their level of attainment in sports. There is a clustering of birth dates just after the cutoff used for selection in age-grouped sports, and it is hypothesized that such relatively older sportspeople may enjoy maturational and physical advantages over their younger peers. There is, however, little empirical evidence of any such advantage. This study investigated whether schoolchildren's physical performance differed according to which quarter of the school year they were born in. Mass, stature, body mass index, cardiorespiratory fitness, strength, and power were measured in 10 to 16 year olds (n = 8,550, 53% male). We expressed test performance as ageand sex-specific z-scores based on reference data with age rounded down to the nearest whole year and also as units normalized for body mass. We then compared these values between yearly birth quarters. There were no significant main effects for differences in anthropometric measures in either sex. Girls born in the first quarter of the school year were significantly stronger than those born at other times when handgrip was expressed as a zscore. As z-scores, all measures were significantly higher in boys born in either the first or second yearly quarters. Relative to body mass, cardiorespiratory fitness was higher in boys born in the first quarter and power was higher in those born in the second quarter. The RAE does not appear to significantly affect girls' performance test scores when they are expressed as z-score or relative to body mass. Boys born in the first and second quarters of the year had a significant physical advantage over their relatively younger peers. These findings have practical bearing if coaches use fitness tests for talent identification and team selection. Categorizing test performance based on rounded down values of whole-year age may disadvantage children born later in the selection year. These relatively younger children may be less to gain selection for teams or training programmes. © 2013 National Strength and Conditioning Association

    Exploring directional and fluctuating asymmetry in the human palate during growth

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    open24siObjectives: Palate morphology is constantly changing throughout an individual's lifespan, yet its asymmetry during growth is still little understood. In this research, we focus on the study of palate morphology by using 3D geometric morphometric approaches to observe changes at different stages of life, and to quantify the impact of directional and fluctuating asymmetry on different areas at different growth stages. Materials and Methods: The sample consists of 183 individuals (1–72 years) from two identified human skeletal collections of 19th and early 20th Century Italian contexts. A 3D-template of 41 (semi)landmarks was applied on digital palate models to observe morphological variation during growth. Results: Asymmetrical components of the morphological structure appears multidirectional on the entire palate surface in individuals <2 years old and become oriented (opposite bilateral direction) between 2 and 6 years of age. Specifically, directional asymmetry differentially impacts palate morphology at different stages of growth. Both the anterior and posterior palate are affected by mild alterations in the first year of life, while between 2 and 6 years asymmetry is segregated in the anterior area, and moderate asymmetry affects the entire palatal surface up to 12 years of age. Our results show that stability of the masticatory system seems to be reached around 13–35 years first by females and then males. From 36 years on both sexes show similar asymmetry on the anterior area. Regarding fluctuating asymmetry, inter-individual variability is mostly visible up to 12 years of age, after which only directional trends can be clearly observed at a group level. Discussion: Morphological structure appears instable during the first year of life and acquires an opposite asymmetric bilateral direction between 2 and 6 years of age. This condition has been also documented in adults; when paired with vertical alteration, anterior/posterior asymmetry seems to characterize palate morphology, which is probably due to mechanical factors during the lifespan. Fluctuating asymmetry is predominant in the first period of life due to a plausible relationship with the strength of morphological instability of the masticatory system. Directional asymmetry, on the other hand, shows that the patterning of group-level morphological change might be explained as a functional response to differential inputs (physiological forces, nutritive and non-nutritive habits, para-masticatory activity as well as the development of speech) in different growth stages. This research has implications with respect to medical and evolutionary fields. In medicine, palate morphology should be considered when planning orthodontic and surgical procedures as it could affect the outcome. As far as an evolutionary perspective is concerned the dominance of directional asymmetries in the masticatory system could provide information on dietary and cultural habits as well as pathological conditions in our ancestors.embargoed_20220511Oxilia G.; Menghi Sartorio J.C.; Bortolini E.; Zampirolo G.; Papini A.; Boggioni M.; Martini S.; Marciani F.; Arrighi S.; Figus C.; Marciani G.; Romandini M.; Silvestrini S.; Pedrosi M.E.; Mori T.; Riga A.; Kullmer O.; Sarig R.; Fiorenza L.; Giganti M.; Sorrentino R.; Belcastro M.G.; Cecchi J.M.; Benazzi S.Oxilia G.; Menghi Sartorio J.C.; Bortolini E.; Zampirolo G.; Papini A.; Boggioni M.; Martini S.; Marciani F.; Arrighi S.; Figus C.; Marciani G.; Romandini M.; Silvestrini S.; Pedrosi M.E.; Mori T.; Riga A.; Kullmer O.; Sarig R.; Fiorenza L.; Giganti M.; Sorrentino R.; Belcastro M.G.; Cecchi J.M.; Benazzi S
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