4,010 research outputs found

    Bloodstream form pre-adaptation to the tsetse fly in Trypanosoma brucei

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    African trypanosomes are sustained in the bloodstream of their mammalian hosts by their extreme capacity for antigenic variation. However, for life cycle progression, trypanosomes also must generate transmission stages called stumpy forms that are pre-adapted to survive when taken up during the bloodmeal of the disease vector, tsetse flies. These stumpy forms are rather different to the proliferative slender forms that maintain the bloodstream parasitaemia. Firstly, they are non proliferative and morphologically distinct, secondly, they show particular sensitivity to environmental cues that signal entry to the tsetse fly and, thirdly, they are relatively robust such that they survive the changes in temperature, pH and proteolytic environment encountered within the tsetse midgut. These characteristics require regulated changes in gene expression to pre-adapt the parasite and the use of environmental sensing mechanisms, both of which allow the rapid initiation of differentiation to tsetse midgut procyclic forms upon transmission. Interestingly, the generation of stumpy forms is also regulated and periodic in the mammalian blood, this being governed by a density-sensing mechanism whereby a parasite-derived signal drives cell cycle arrest and cellular development both to optimise transmission and to prevent uncontrolled parasite multiplication overwhelming the host.In this review we detail recent developments in our understanding of the molecular mechanisms that underpin the production of stumpy forms in the mammalian bloodstream and their signal perception pathways both in the mammalian bloodstream and upon entry into the tsetse fly. These discoveries are discussed in the context of conserved eukaryotic signalling and differentiation mechanisms. Further, their potential to act as targets for therapeutic strategies that disrupt parasite development either in the mammalian bloodstream or upon their transmission to tsetse flies is also discussed

    Monitoring urban heat island through google earth engine. Potentialities and difficulties in different cities of the United States

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    The aim of this work is to exploit the large-scale analysis capabilities of the innovative Google Earth Engine platform in order to investigate the temporal variations of the Urban Heat Island phenomenon as a whole. A intuitive methodology implementing a large-scale correlation analysis between the Land Surface Temperature and Land Cover alterations was thus developed. The results obtained for the Phoenix MA are promising and show how the urbanization heavily affects the magnitude of the UHI effects with significant increases in LST. The proposed methodology is therefore able to efficiently monitor the UHI phenomenon

    Quantum-enhanced gyroscopy with rotating anisotropic Bose–Einstein condensates

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    High-precision gyroscopes are a key component of inertial navigation systems. By considering matter wave gyroscopes that make use of entanglement it should be possible to gain some advantages in terms of sensitivity, size, and resources used over unentangled optical systems. In this paper we consider the details of such a quantum-enhanced atom interferometry scheme based on atoms trapped in a carefully-chosen rotating trap. We consider all the steps: entanglement generation, phase imprinting, and read-out of the signal and show that quantum enhancement should be possible in principle. While the improvement in performance over equivalent unentangled schemes is small, our feasibility study opens the door to further developments and improvements

    Hubungan antara Konformitas dengan Prokrastinasi Akademik pada Mahasiswa Bengkulu yang Bersekolah di YOGYAKARTA

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    Penelitian ini bertujuan untuk mengetahui hubungan antara konformitas dengan prokrastinasi akademik pada mahasiswa Bengkulu yang bersekolah di Yogyakarta. Metode pengumpulan data yang digunakan dalam penelitian ini adalah metode kuantitatif, data berupa skor diambil menggunakan skala konformitas dan skala prokrastinasi akademik. Teknik analisis data yang digunakan adalah korelasi product moment dari Pearson dengan bantuan komputer program SPSS versi 16,0 for Windows. Analisis korelasi product moment menghasilkan (r)sebesar 0,564 dengan (p) taraf signifikan 0,000 (p < 0,01) yang berarti ada hubungan positif yang sangat signifikan antara konformitas dengan prokrastinasi akademik pada mahasiswa Provinsi Bengkulu yang bersekolah di Yogyakarta. Hasil analisis juga menunjukan koefisien determinasi (r2) yang diperoleh (r2) sebesar 0,318. Mayoritas subyek penelitian (55%) memiliki konformitas dalam kategori sedang dan mayoritas subyek penelitian (36,61%) memiliki prokrastinasi akademik dalam kategori rendah.Bedasarkan hasil penelitian dapat disimpulkan bahwa semakin tinggi konformitas maka semakin tinggi pula prokrastinasi akademik, sebaliknya semakin rendah konformitas maka semakin rendah pula prokrastinasi akademik pada mahasiswa Bengkulu

    Observations of microquasars with the MAGIC telescope

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    We report on the results from the observations in very high energy band (VHE, E_gamma > 100GeV) of the black hole X-ray binary (BHXB) Cygnus X-1. The observations were performed with the MAGIC telescope, for a total of 40 hours during 26 nights, spanning the period between June and November 2006. We report on the results of the searches for steady and variable gamma-ray signals, including the first experimental evidence for an intense flare, of duration between 1.5 and 24 hours.Comment: Contribution to the 30th ICRC, Merida Mexico, July 2007 on behalf of the MAGIC Collaboratio

    Structuring reality through the faultlines lens: the effects of structure, fairness, and status conflict on the activated faultlines-performance relationship

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    We investigate how activated team faultlines represent an informal sensemaking structure through which teammates interpret their social reality. Constructed from inter-subgroup comparisons, activated faultlines likely result in status perceptions that are ambiguous or illegitimate. Thus, activated faultlines threaten the justice climate within the team, which drives status conflict, impairing team performance. We explore the effects of team structure clarity in providing certainty or legitimacy around status and structure, ameliorating the negative effect of activated faultlines on team justice climate. We tested our model using a multi-source (three sources), multi-wave cross-lagged design (four waves) on a sample of 271 employees and 41 leaders in 41 teams. We found that the negative relationship between activated faultlines and team performance was mediated by the team justice climate—status conflict causal chain. We also found that team structure clarity reduced activated faultlines negative effect on team justice climate. The results highlight the value of using team faultlines, the social identity approach, and justice theories to understand how diverse teams interpret their social reality that influences their performance. Furthermore, our research provides practical guidance to managers in building clear team structures that minimize the harmful effects of activated faultlines on justice perceptions and team performance.info:eu-repo/semantics/acceptedVersio
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