Exchange Rate Policy in Small Rich Economies

We look at the exchange rate policy choices and outcomes for small rich economies. Small rich economies face significant policy challenges due to proportionately greater economic volatility than larger economies. These economies usually choose some form of fixed exchange rate regime, particularly in the very small economies where the per capita cost of independent monetary policy is relatively high. When such countries do choose a free or managed floating regime, they appear to derive no benefit from those regimes; their exchange rate volatility seems to rise without any significant change in fundamental economic volatility. Thus, for these countries, floating exchange rates seem to create problems for policy makers without solving any.Small economies, Exchange rate regimes

Rotational Correlation Functions of Single Molecules

Single molecule rotational correlation functions are analyzed for several reorientation geometries. Even for the simplest model of isotropic rotational diffusion our findings predict non-exponential correlation functions to be observed by polarization sensitive single molecule fluorescence microscopy. This may have a deep impact on interpreting the results of molecular reorientation measurements in heterogeneous environments.Comment: 5 pages, 4 figure

CPT\cal CPT-invariant two-fermion Dirac equation with extended hyperfine operator

For the S-states of muonium and positronium, the hyperfine shifts to the order $\alpha^6$ of a recently derived two-fermion equation with explicit $\cal CPT$-invariance are checked against the results of a nonrelativistic reduction, and the leading $\alpha^8$ shifts are calculated. An additional hyperfine operator is discovered which can milden the singularity for $r\to 0$ of the Dirac hyperfine operator, such that the resulting extended operator can be used nonperturbatively. The binding correction to magnetic moments is mentioned

Zooplankton Community Structure in Seagrass Ecosystem, Tongkaina Village, Bunaken Darat District, Manado City

This study aims to determine the type and community structure of zooplankton in the Tongkaina seagrass aquatic ecosystem. Sampling was carried out at 3 location points using plankton nets. Plankton net was drawn along 50 meters from the sea towards the beach. There are 14 genera of zooplankton in the morning and 17 genera in the afternoon. The total density of zooplankton in the morning was 0.064 individual/l , and in the afternoon 0.114 individual/l. The highest density of zooplankton in the morning is Limacina and in the afternoon, Calanus. The zooplankton Diversity Index (H ') in the morning is 2.5907 and in the afternoon is 2.7321, indicating that the diversity level is less diverse. Morning uniformity (e) zooplankton index was 0.5614 and in the afternoon 0.5267, showed that the distribution pattern of zooplankton was moderate. The zooplankton dominance (C) index in the morning was 0.0783 and in the afternoon 0.0720. This shows that there is no dominant genus. Water conditions fall into the good category due to the temperature, salinity, and pH that are quite stable and are still within the limits of feasibility for zooplankton life.    Keywords: Zooplankton, Community Structure, Seagrass, Tongkaina Waters.Keywords: Zooplankton, Community Structure, Seagrass, Tongkaina Waters  ABSTRAKPenelitian ini bertujuan untuk mengetahui jenis dan struktur komunitas zooplankton yang ada di ekosistem perairan lamun Tongkaina. Pengambilan sampel dilakukan pada 3 titik lokasi dengan menggunakan jaring plankton.Plankton net ditarik sepanjang 50 meter dari laut ke arah pantai. Terdapat 14 genus zooplankton pada waktu pagi dan 17 genus pada waktu sore. Kepadatan total zooplankton pada waktu pagi hari 0.064 ind/l dan sore hari 0.114 ind/l. Kepadatan relatif zooplankton yang tertinggi pada pagi hari yaitu Limacina dan pada sore hari yaitu Calanus. Adapun Indeks Keanekaragaman (H’) zooplankton pada pagi hari sebesar 2.5907 dan sore hari sebesar 2.7321, menunjukkan bahwa tingkat keanekaragaman kurang beragam. Indeks Keseragaman (e) zooplankton pada pagi hari sebesar 0.5614 dan pada sore hari 0.5267, menunjukkan bahwa pola sebaran zooplankton sedang. Indeks Dominansi (C) zooplankton pada waktu pagi hari sebesar 0.0783 dan sore hari 0.0720. Hal ini menunjukkan bahwa tidak ada genus yang dominan. Kondisi perairan masuk dalam kategori baik dikarenakan suhu, salinitas dan pH cukup stabil dan masih berada dalam batas kelayakan bagi kehidupan zooplankton.Kata kunci: Zooplankton, Struktur Komunitas, Lamun,  Perairan Tongkaina

Electromagnetic Polarizabilities of Nucleons bound in 40^{40}Ca, 16^{16}O and 4^4He

Differential cross sections for elastic scattering of photons have been measured for $^{40}$Ca at energies of 58 and 74 MeV and for $^{16}$O and $^4$He at 61 MeV, in the angular range from 45$^o$ to 150$^o$. Evidence is obtained that there are no significant in-medium modifications of the electromagnetic polarizabilities except for those originating from meson exchange currents.Comment: 20 pages including 5 Figure

Spin dynamics of wave packets evolving with the Dirac Hamiltonian in atoms with high Z

The motion of circular WP for one electron in central Coulomb field with high Z is calculated. The WP is defined in terms of solutions of the Dirac equation in order to take into account all possible relevant effects in particular the spin-orbit potential. A time scale is defined within which spin dynamics must be taken into account mainly in the atoms with high Z. Within this time scale there exists a mechanism of collapses and revivals of the spin already shown by the authors for harmonic oscillator potential and called the 'spin-orbit pendulum'. However this effect has not the exact periodicity of the simpler model, but the WP's spatial motion is nevertheless quite similar.Comment: 17 pages, 9 figures, LaTeX2e, uses IOP style files (included). Title changed, one reference adde

Probing impulsive strain propagation with x-ray pulses

Pump-probe time-resolved x-ray diffraction of allowed and nearly forbidden reflections in InSb is used to follow the propagation of a coherent acoustic pulse generated by ultrafast laser-excitation. The surface and bulk components of the strain could be simultaneously measured due to the large x-ray penetration depth. Comparison of the experimental data with dynamical diffraction simulations suggests that the conventional model for impulsively generated strain underestimates the partitioning of energy into coherent modes.Comment: 4 pages, 2 figures, LaTeX, eps. Accepted for publication in Phys. Rev. Lett. http://prl.aps.or

Dietary garlic and hip osteoarthritis: evidence of a protective effect and putative mechanism of action

Background Patterns of food intake and prevalent osteoarthritis of the hand, hip, and knee were studied using the twin design to limit the effect of confounding factors. Compounds found in associated food groups were further studied in vitro. Methods Cross-sectional study conducted in a large population-based volunteer cohort of twins. Food intake was evaluated using the Food Frequency Questionnaire; OA was determined using plain radiographs. Analyses were adjusted for age, BMI and physical activity. Subsequent in vitro studies examined the effects of allium-derived compounds on the expression of matrix-degrading proteases in SW1353 chondrosarcoma cells. Results Data were available, depending on phenotype, for 654-1082 of 1086 female twins (median age 58.9 years; range 46-77). Trends in dietary analysis revealed a specific pattern of dietary intake, that high in fruit and vegetables, showed an inverse association with hip OA (p = 0.022). Consumption of 'non-citrus fruit' (p = 0.015) and 'alliums' (p = 0.029) had the strongest protective effect. Alliums contain diallyl disulphide which was shown to abrogate cytokine-induced matrix metalloproteinase expression. Conclusions Studies of diet are notorious for their confounding by lifestyle effects. While taking account of BMI, the data show an independent effect of a diet high in fruit and vegetables, suggesting it to be protective against radiographic hip OA. Furthermore, diallyl disulphide, a compound found in garlic and other alliums, represses the expression of matrix-degrading proteases in chondrocyte-like cells, providing a potential mechanism of action

Estimating the number needed to treat from continuous outcomes in randomised controlled trials: methodological challenges and worked example using data from the UK Back Pain Exercise and Manipulation (BEAM) trial

Background Reporting numbers needed to treat (NNT) improves interpretability of trial results. It is unusual that continuous outcomes are converted to numbers of individual responders to treatment (i.e., those who reach a particular threshold of change); and deteriorations prevented are only rarely considered. We consider how numbers needed to treat can be derived from continuous outcomes; illustrated with a worked example showing the methods and challenges. Methods We used data from the UK BEAM trial (n = 1, 334) of physical treatments for back pain; originally reported as showing, at best, small to moderate benefits. Participants were randomised to receive 'best care' in general practice, the comparator treatment, or one of three manual and/or exercise treatments: 'best care' plus manipulation, exercise, or manipulation followed by exercise. We used established consensus thresholds for improvement in Roland-Morris disability questionnaire scores at three and twelve months to derive NNTs for improvements and for benefits (improvements gained+deteriorations prevented). Results At three months, NNT estimates ranged from 5.1 (95% CI 3.4 to 10.7) to 9.0 (5.0 to 45.5) for exercise, 5.0 (3.4 to 9.8) to 5.4 (3.8 to 9.9) for manipulation, and 3.3 (2.5 to 4.9) to 4.8 (3.5 to 7.8) for manipulation followed by exercise. Corresponding between-group mean differences in the Roland-Morris disability questionnaire were 1.6 (0.8 to 2.3), 1.4 (0.6 to 2.1), and 1.9 (1.2 to 2.6) points. Conclusion In contrast to small mean differences originally reported, NNTs were small and could be attractive to clinicians, patients, and purchasers. NNTs can aid the interpretation of results of trials using continuous outcomes. Where possible, these should be reported alongside mean differences. Challenges remain in calculating NNTs for some continuous outcomes