62 research outputs found
Democracy and Development: Lessons from Turkish Experience Applied to Ethiopia
Ethiopia\u27s development problems are not unique. Similar problems have been (and are being) encountered in many other countries. Turkey\u27s successful transformation from a politically and economically backward, stagnant country into one of the most dynamic societies of our time offers an example of the kind of progress Ethiopia can hope for during the 21st century. How did Turkey transform itself in little over half a century? Turkey and Ethiopia have similarities. Both have complicated geography but lack major wealth in minerals and oil. Both have suffered strife and political turmoil. Both have unstable and aggressive neighbors. Both carry a heavy burden of history, but neither has ever been colonized or effectively conquered. When the modern Turkish Republic was proclaimed in 1923, it had barely 12 million people most of whom were illiterate and lived in a countryside which had barely changed over several thousand years. The country lacked infrastructure and industry. Its exports consisted of tobacco, nuts, dried fruit and carpets, produce of traditional peasant agriculture. It was equally backward politically. A small elite class led by Mustafa Kemal Ataturk--who ruled as a benevolent but firm monarch--was determined to turn the country into an open society moving toward European civilization and modern development. Today Turkey has over 70 million people, almost all literate. All Turkish children go to school. Every Turkish village has electricity and running water. Everybody has access to doctors and medicines. Turkey\u27s exports totaled $60 billion in 2004 and included automobiles, televisions, and manufactured goods of many kinds, huge amounts of processed food and vast quantities of textiles and other consumer goods. A majority of Turks now live in cities and enjoy a steadily rising standard of living. More than 30 universities produce skilled specialists. Communication and transportation systems approach those of most countries in Europe. A network of super-highways is now being built. For more than 50 years Turkey has enjoyed a democratic political system, a free press, and lively cultural life. It is likely to join the European Union by 2020. Turkey\u27s experience offers comparisons and lessons worth considering as Ethiopia embarks on a period of accelerated development
Reflections on Development in Ethiopia
I visited Ethiopia frequently and traveled extensively in all parts of the country during the Derg period. I observed firsthand the deleterious effects of the Derg\u27s attempt to turn the country into a communist people\u27s republic .[1] Since the fall of the Derg in May 1991, I have made fifteen visits to Ethiopia, usually for periods of several weeks, totaling well over a year of travel in the country in all. During these same years I have also spent time in sixteen other post-communist countries, ranging from Slovenia and Armenia to Mongolia, observing the political, economic and social problems of recovering from communism and restoring cultural heritage. I delivered a paper summarizing some of this experience in comparison with Ethiopia at the 14th International Ethiopian Studies Conference in Addis Ababa in November 2000.[2] The present discussion is based on observations from travel in Ethiopia, discussions at conferences, and familiarity with literature relevant to the subject of economic and social development
Reflections on Development in Ethiopia
I visited Ethiopia frequently and traveled extensively in all parts of the country during the Derg period. I observed firsthand the deleterious effects of the Derg\u27s attempt to turn the country into a communist people\u27s republic .1 Since the fall of the Derg in May 1991 I have made eleven visits to Ethiopia (with a twelfth scheduled for June 2001), usually for periods of several weeks, totaling well over a year of travel in the country in all. During these same years I have also spent time in 16 other post-communist countries, ranging from Slovenia and Armenia to Mongolia, observing the political, economic and social problems of recovering from communism and restoring cultural heritage. I delivered a paper summarizing some of this experience in comparison with Ethiopia at the 14th International Ethiopian Studies Conference in Addis Ababa in November 2000.2 The present discussion is based on observations from travel in Ethiopia, discussions at the 14th IESC and other conferences, and familiarity with literature relevant to the subject of economic and social development
Masses, radii, and orbits of small Kepler planets : The transition from gaseous to rocky planets
We report on the masses, sizes, and orbits of the planets orbiting 22 Kepler stars. There are 49 planet candidates around these stars, including 42 detected through transits and 7 revealed by precise Doppler measurements of the host stars. Based on an analysis of the Kepler brightness measurements, along with high-resolution imaging and spectroscopy, Doppler spectroscopy, and (for 11 stars) asteroseismology, we establish low false-positive probabilities (FPPs) for all of the transiting planets (41 of 42 have an FPP under 1%), and we constrain their sizes and masses. Most of the transiting planets are smaller than three times the size of Earth. For 16 planets, the Doppler signal was securely detected, providing a direct measurement of the planet's mass. For the other 26 planets we provide either marginal mass measurements or upper limits to their masses and densities; in many cases we can rule out a rocky composition. We identify six planets with densities above 5 g cm-3, suggesting a mostly rocky interior for them. Indeed, the only planets that are compatible with a purely rocky composition are smaller than 2 R ⊕. Larger planets evidently contain a larger fraction of low-density material (H, He, and H2O).Peer reviewedFinal Accepted Versio
SARS-CoV-2 mRNA vaccinations fail to elicit humoral and cellular immune responses in patients with multiple sclerosis receiving fingolimod
BACKGROUND: SARS-CoV-2 mRNA vaccination of healthy individuals is highly immunogenic and protective against severe COVID-19. However, there are limited data on how disease-modifying therapies (DMTs) alter SARS-CoV-2 mRNA vaccine immunogenicity in patients with autoimmune diseases. METHODS: As part of a prospective cohort study, we investigated the induction, stability and boosting of vaccine-specific antibodies, B cells and T cells in patients with multiple sclerosis (MS) on different DMTs after homologous primary, secondary and booster SARS-CoV-2 mRNA vaccinations. Of 126 patients with MS analysed, 105 received either anti-CD20-based B cell depletion (aCD20-BCD), fingolimod, interferon-β, dimethyl fumarate, glatiramer acetate, teriflunomide or natalizumab, and 21 were untreated MS patients for comparison. RESULTS: In contrast to all other MS patients, and even after booster, most aCD20-BCD- and fingolimod-treated patients showed no to markedly reduced anti-S1 IgG, serum neutralising activity and a lack of receptor binding domain-specific and S2-specific B cells. Patients receiving fingolimod additionally lacked spike-reactive CD4(+) T cell responses. The duration of fingolimod treatment, rather than peripheral blood B and T cell counts prior to vaccination, determined whether a humoral immune response was elicited. CONCLUSIONS: The lack of immunogenicity under long-term fingolimod treatment demonstrates that functional immune responses require not only immune cells themselves, but also access of these cells to the site of inoculation and their unimpeded movement. The absence of humoral and T cell responses suggests that fingolimod-treated patients with MS are at risk for severe SARS-CoV-2 infections despite booster vaccinations, which is highly relevant for clinical decision-making and adapted protective measures, particularly considering additional recently approved sphingosine-1-phosphate receptor antagonists for MS treatment
The TESS Grand Unified Hot Jupiter Survey. I. Ten TESS Planets
We report the discovery of ten short-period giant planets (TOI-2193A b,
TOI-2207 b, TOI-2236 b, TOI-2421 b, TOI-2567 b, TOI-2570 b, TOI-3331 b,
TOI-3540A b, TOI-3693 b, TOI-4137 b). All of the planets were identified as
planet candidates based on periodic flux dips observed by NASA's Transiting
Exoplanet Survey Satellite (TESS). The signals were confirmed to be from
transiting planets using ground-based time-series photometry, high angular
resolution imaging, and high-resolution spectroscopy coordinated with the TESS
Follow-up Observing Program. The ten newly discovered planets orbit relatively
bright F and G stars (,~ between 4800 and 6200 K).
The planets' orbital periods range from 2 to 10~days, and their masses range
from 0.2 to 2.2 Jupiter masses. TOI-2421 b is notable for being a Saturn-mass
planet and TOI-2567 b for being a ``sub-Saturn'', with masses of and Jupiter masses, respectively. In most cases, we
have little information about the orbital eccentricities. Two exceptions are
TOI-2207 b, which has an 8-day period and a detectably eccentric orbit (), and TOI-3693 b, a 9-day planet for which we can set an upper
limit of . The ten planets described here are the first new planets
resulting from an effort to use TESS data to unify and expand on the work of
previous ground-based transit surveys in order to create a large and
statistically useful sample of hot Jupiters.Comment: 44 pages, 15 tables, 21 figures; revised version submitted to A
Dopamine Modulates Persistent Synaptic Activity and Enhances the Signal-to-Noise Ratio in the Prefrontal Cortex
The importance of dopamine (DA) for prefrontal cortical (PFC) cognitive functions is widely recognized, but its mechanisms of action remain controversial. DA is thought to increase signal gain in active networks according to an inverted U dose-response curve, and these effects may depend on both tonic and phasic release of DA from midbrain ventral tegmental area (VTA) neurons.We used patch-clamp recordings in organotypic co-cultures of the PFC, hippocampus and VTA to study DA modulation of spontaneous network activity in the form of Up-states and signals in the form of synchronous EPSP trains. These cultures possessed a tonic DA level and stimulation of the VTA evoked DA transients within the PFC. The addition of high (≥1 µM) concentrations of exogenous DA to the cultures reduced Up-states and diminished excitatory synaptic inputs (EPSPs) evoked during the Down-state. Increasing endogenous DA via bath application of cocaine also reduced Up-states. Lower concentrations of exogenous DA (0.1 µM) had no effect on the up-state itself, but they selectively increased the efficiency of a train of EPSPs to evoke spikes during the Up-state. When the background DA was eliminated by depleting DA with reserpine and alpha-methyl-p-tyrosine, or by preparing corticolimbic co-cultures without the VTA slice, Up-states could be enhanced by low concentrations (0.1–1 µM) of DA that had no effect in the VTA containing cultures. Finally, in spite of the concentration-dependent effects on Up-states, exogenous DA at all but the lowest concentrations increased intracellular current-pulse evoked firing in all cultures underlining the complexity of DA's effects in an active network.Taken together, these data show concentration-dependent effects of DA on global PFC network activity and they demonstrate a mechanism through which optimal levels of DA can modulate signal gain to support cognitive functioning
Cross-reactive CD4+ T cells enhance SARS-CoV-2 immune responses upon infection and vaccination
The functional relevance of pre-existing cross-immunity to SARS-CoV-2 is a subject of intense debate. Here, we show that human endemic coronavirus (HCoV)-reactive and SARS-CoV-2-cross-reactive CD4+ T cells are ubiquitous but decrease with age. We identified a universal immunodominant coronavirus-specific spike peptide (S816-830) and demonstrate that pre-existing spike- and S816-830-reactive T cells were recruited into immune responses to SARS-CoV-2 infection and their frequency correlated with anti-SARS-CoV-2-S1-IgG antibodies. Spike-cross-reactive T cells were also activated after primary BNT162b2 COVID-19 mRNA vaccination displaying kinetics similar to secondary immune responses. Our results highlight the functional contribution of pre-existing spike-cross-reactive T cells in SARS-CoV-2 infection and vaccination. Cross-reactive immunity may account for the unexpectedly rapid induction of immunity following primary SARS-CoV-2 immunization and the high rate of asymptomatic/mild COVID-19 disease courses
Formation of Low Volatility Organic Compounds and Secondary Organic Aerosol from Isoprene Hydroxyhydroperoxide Low-NO Oxidation
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