The N-terminal region (A/B) of rat thyroid hormone receptors alpha 1, beta 1, but not beta 2 contains a strong thyroid hormone-dependent transactivation function.

In this study we have investigated the role of the N-terminal region of thyroid hormone receptors (TRs) in thyroid hormone (TH)-dependent transactivation of a thymidine kinase promoter containing TH response elements composed either of a direct repeat or an inverted palindrome. Comparison of rat TR beta 1 with TR beta 2 provides an excellent model since they share identical sequences except for their N termini. Our results show that TR beta 2 is an inefficient TH-dependent transcriptional activator. The degree of transactivation corresponds to that observed for the mutant TR delta N beta 1/2, which contains only those sequences common to TR beta 1 and TR beta 2. Thus, TH-dependent activation appears to be associated with two separate domains. The more important region, however, is embedded in the N-terminal domain. Furthermore, the transactivating property of TR alpha 1 was also localized to the N-terminal domain between amino acids 19 and 30. Using a coimmunoprecipitation assay, we show that the differential interaction of the N terminus of TR beta 1 and TR beta 2 with transcription factor IIB correlates with the TR beta 1 activation function. Hence, our results underscore the importance of the N-terminal region of TRs in TH-dependent transactivation and suggest that a transactivating signal is transmitted to the general transcriptional machinery via a direct interaction of the receptor N-terminal region with transcription factor IIB.

Intersubunit contacts made by tryptophan 120 with biotin are essential for both strong biotin binding and biotin-induced tighter subunit association of streptavidin.

In natural streptavidin, tryptophan 120 of each subunit makes contacts with the biotin bound by an adjacent subunit through the dimer-dimer interface. To understand quantitatively the role of tryptophan 120 and its intersubunit communication in the properties of streptavidin, a streptavidin mutant in which tryptophan 120 is converted to phenylalanine was produced and characterized. The streptavidin mutant forms a tetrameric molecule and binds one biotin per subunit, as does natural streptavidin, indicating that the mutation of tryptophan 120 to phenylalanine has no significant effect on the basic properties of streptavidin. However, its biotin-binding affinity was reduced substantially, to approximately 10(8) M-1, indicating that the contact made by tryptophan 120 to biotin has a considerable contribution to the extremely tight biotin binding by streptavidin. The mutant retained bound biotin over a wide pH range or with the addition of urea up to 6 M at neutral pH. However, bound biotin was efficiently released by the addition of excess free biotin due, presumably, to exchange reactions. Electrophoretic analysis revealed that the intersubunit contact made by tryptophan 120 to biotin through the dimer-dimer interface is the major interaction responsible for the biotin-induced, tighter subunit association of streptavidin. In addition, the mutant has weaker subunit association than natural streptavidin even in the absence of biotin, indicating that tryptophan 120 also contributes to the subunit association of tetramers in the absence of biotin.

Strong natural selection causes microscale allozyme variation in a marine snail.

Natural selection is one of the most fundamental processes in biology. However, there is still a controversy over the importance of selection in microevolution of molecular traits. Despite the general lack of data most authors hold the view that selection on molecular characters may be important, but at lower rates than selection on most phenotypic traits. Here we present evidence that natural selection may contribute substantially to molecular variation on a scale of meters only. In populations of the marine snail Littorina saxatilis living on exposed rocky shores, steep microclines in allele frequencies between splash and surf zone groups are present in the enzyme aspartate aminotransferase (allozyme locus Aat; EC. 2.6.1.1). We followed one population over 7 years, including a period of strong natural perturbation. The surf zone part of the population dominated by the allele Aat100 was suddenly eliminated by a bloom of a toxin-producing microflagellate. Downshore migration of splash zone snails with predominantly Aat120 alleles resulted in a drastic increase in surf zone frequency of Aat120, from 0.4 to 0.8 over 2 years. Over the next four to six generations, however, the frequency of Aat120 returned to the original value. We estimated the coefficient of selection of Aat120 in the surf zone to be about 0.4. Earlier studies show similar or even sharper Aat clines in other countries. Thus, we conclude that microclinal selection is an important evolutionary force in this system.

Optical and ultraviolet observations of a strong flare in the young, single K2 dwarf LQ Hya

We present high-resolution optical echelle spectra and IUE observations during a strong flare on 1993 December 22 in the very active, young, rapidly rotating, single K2 dwarf LQ Hya. The initial impulsive phase of the flare, which started sometime between 2:42 ut and 4:07 ut, was characterized by strong optical continuum enhancement and blueshifted emission lines with broad wings. The optical chromospheric lines reached their maximum intensity at ≈ 5:31 ut, by which time the blueshift vanished and the optical continuum enhancement had sharply decreased. Thereafter, the line emission slowly decreased and the lines redshift in a gradual phase that lasted at least two more hours. The Mg II lines behaved similarly. Quiescent C IV flux levels were not recovered until 21 h later, though a data gap and a possible second flare make the interpretation uncertain. In addition to the typically flare-enhanced emission lines (e.g., H α and H β), we observe He I D_3 going into emission, plus excess emission (after subtraction of the quiescent spectrum) in other He I and several strong neutral metal lines (e.g., Mg I b). Flare enhancement of the far-ultraviolet continuum generally agrees with an Si I recombination model. We estimate the total flare energy, and discuss the broad components, asymmetries and Doppler shifts seen in some of the emission lines.

Strong governments, weak banks. CEPS Policy Brief No. 305, 25 November 2013

Banks in the northern eurozone have capital ratios that are, on average, less than half of the capital ratios of banks in the eurozone’s periphery. The authors explain this by the fact that northern eurozone banks profit from the financial solidity of their governments and follow business strategies aimed at issuing too much subsidised debt. In doing so, they weaken their balance sheets and become more fragile – less able to withstand future shocks. Paradoxically, financially strong governments breed fragile banks. The opposite occurs in countries with financially weak governments. In these countries banks are forced to strengthen themselves because they are unable to rely on their governments. As a result they have significantly more capital and reserves than banks in the northern eurozone. Recommendations More than in the south, the governments of northern Europe should stand up and force the banks to issue more equity. This should go much further than what is foreseen in the Basel III accord. If the experience of the southern eurozone countries is any guide, banks in the north of the eurozone should at least double the capital and the reserves as a percentage of their balance sheets. Failure to do so risks destroying the financial solidity of the northern European governments when, in the future, negative shocks force these governments to come to the rescue of their undercapitalised banks. The new responsibilities entrusted to the European Central Bank as the single supervisor in the eurozone create a unique opportunity for that institution to change the regulatory and supervisory culture in the eurozone – one that has allowed the large banks to continue living dangerously, with insufficient capital.

Differentiated Europe needs strong institutions. CHALLENGE EUROPE Issue 22 - Challenges and new beginnings: Priorities for the EU's new leadership, September 2014.

Differentiated Europe can be analysed in terms of the three meta-challenges outlined in this publication – stagnation, fragmentation and legitimacy. My argument is simple: stagnation or the prospect of it has been a catalyst for differentiation, fragmentation poses a risk of differentiation gone too far and legitimacy of differentiation is embedded on institutional cohesion and good results.

Georgian dilemmas. Between a strong state and democracy. Point of View No. 29, July 2012

No abstract.

A Strong Europe in a Globalized World: From the Hungarian to the Polish presidency of the Council of the European Union. ACES Working Papers, 2011

On June 17, 2011, the Center for Transatlantic Relations – together with the Center for European Policy Analysis, the Polish Institute of International Affairs in Warsaw, and the Embassies of Hungary and Poland – hosted authors writing on the theme “A Strong Europe in a Globalized World,” and who offered in-depth, substantive reflections about how the United States and Europe can work together more closely in meeting global challenges. Drawing on the agendas of the outgoing and incoming EU Presidencies of the Council of the European Union – Hungary and Poland respectively – authors focused on the importance of a strong US-EU partnership in the face of mounting global challenges, from the current financial and economic crisis through the insecurities of energy markets and the promise of the Arab Spring. Authors explored in depth four key areas of shared interests: A Global Perspective (Transatlantic Partnership in a Globalized World); Achievements and Deliverables of Eastern Partnership; Euro-Atlantic Perspectives for the Balkans; and Common Challenges of Energy Security. Senior Hungarian and Polish government officials, subject matter experts, private sector actors, and think tank scholars participated.

Putin: The morally depraved degradation of a strong state leader. CEPS Commentary, 31 March 2015

In a new CEPS Commentary, Michael Emerson calls for an end to diplomatic euphemisms in describing Putin’s tragic degradation of Russia, its political regime and society. The assassination of Boris Nemtsov on February 27th signals one more step down this dreadful path.

Shall Tunisia Succeed in Becoming a Strong Democratic State? EUSpring Arab Citizenship Review No. 13, December 2015

From the Introduction. Arab revolutions have sparked real hopes for democracy, but the situation varies from one state to another and change has taken various directions, with unpredictable outcomes in the future. In light of current events, most of these countries seem to have failed in their democratic transition and also face the dissolution of their state apparatus in bloody civil wars. This leaves the door open to interpretations associating democracy with chaos. In this view, preserving post-colonial states – authoritarian in most cases – is better than having no state at all. This partially justified the coup that took place in Egypt, where the ‘Deep State’ has recovered its capabilities in a dictatorial manner. The Arab world thus faced an impasse: the state is either stable but authoritarian or democratic yet threatened with dissolution. The dilemma results in an impossible choice between stable dictatorship or freedom ending in chaos.