Physiological Epicotyl Dormancy and Recalcitrant Storage Behaviour in Seeds of Two Tropical Fabaceae (Subfamily Caesalpinioideae) Species

BACKGROUND AND AIMS: Physiological epicotyl dormancy in which the epicotyl elongates inside the seed before the shoot emerges has been reported for only a few tropical rainforest species, all of which are trees that produce recalcitrant seeds. In studies on seeds of Fabaceae in Sri Lanka, we observed a considerable time delay in shoot emergence following root emergence in seeds of the introduced caesalpinioid legumes Brownea coccinea and Cynometra cauliflora. Thus, our aim was to determine if seeds of these two tropical rainforest trees have physiological epicotyl dormancy, and also if they are recalcitrant, i.e. desiccation sensitive. METHODOLOGY: Fresh seeds were (i) dried to various moisture levels, and (ii) stored at -1 and 5 °C to determine loss (or not) of viability and thus type of seed storage behaviour (orthodox, recalcitrant or intermediate). To identify the kind of dormancy, we tested the effect of scarification on imbibition and monitored radicle emergence and epicotyl growth (inside the seed) and emergence. PRINCIPAL RESULTS: FRESH SEEDS OF BOTH SPECIES HAD HIGH MOISTURE CONTENT (MC): 50 % for C. cauliflora and 30 % for B. coccinea. Further, all seeds of C. cauliflora and the majority of those of B. coccinea lost viability when dried to 15 % MC; most seeds of both species also lost viability during storage at -1 or 5 °C. Intact seeds of both species were water permeable, and radicles emerged in a high percentage of them inHowever, shoot emergence lagged behind root emergence by 77 ± 14 days in B. coccinea and by 38 ± 4 days in C. cauliflora. Further, plumule growth inside seeds of C. cauliflora began almost immediately after radicle emergence but not until ∼30-35 days in B. coccinea seeds. CONCLUSIONS: Seeds of both species are recalcitrant and have physiological epicotyl dormancy. The kind of physiological epicotyl dormancy in seeds of C. cauliflora has not been described previously; the formula is C(nd) (root)-[Formula: see text] (epicotyl)

Mid-IR supercontinuum generation in birefringent, low loss, ultra-high numerical aperture Ge-As-Se-Te chalcogenide step-index fiber

This work reports on the fabrication and subsequent supercontinuum generation in a Ge-As-Se-Te/Ge-As-Se core/clad chalcogenide step-index fiber with an elliptical-core and an ultra-high numerical aperture of 1.88 ± 0.02 from 2.5 - 15 µm wavelength. The fiber has very low transmission loss of < 2 dB/m from 5-11 µm and a minimum loss of 0.72 ± 0.04 dB/m at 8.56 µm. Supercontinuum spanning from 2.1 µm to 11.5 µm with an average power of ∼6.5 mW was achieved by pumping a ∼16 cm fiber with a minor/major axis core diameter of 4.2/5.2 µm with 250 fs pulses at 4.65 µm wavelength and a repetition rate of 20.88 MHz. The effect of the elliptical-core was investigated by means of mechanical rotation of the fiber relative to the linear pump polarization, and it was found to cause a shift in the supercontinuum spectral edges by several hundred nanometers

Nonperturbative renormalization group approach to frustrated magnets

This article is devoted to the study of the critical properties of classical XY and Heisenberg frustrated magnets in three dimensions. We first analyze the experimental and numerical situations. We show that the unusual behaviors encountered in these systems, typically nonuniversal scaling, are hardly compatible with the hypothesis of a second order phase transition. We then review the various perturbative and early nonperturbative approaches used to investigate these systems. We argue that none of them provides a completely satisfactory description of the three-dimensional critical behavior. We then recall the principles of the nonperturbative approach - the effective average action method - that we have used to investigate the physics of frustrated magnets. First, we recall the treatment of the unfrustrated - O(N) - case with this method. This allows to introduce its technical aspects. Then, we show how this method unables to clarify most of the problems encountered in the previous theoretical descriptions of frustrated magnets. Firstly, we get an explanation of the long-standing mismatch between different perturbative approaches which consists in a nonperturbative mechanism of annihilation of fixed points between two and three dimensions. Secondly, we get a coherent picture of the physics of frustrated magnets in qualitative and (semi-) quantitative agreement with the numerical and experimental results. The central feature that emerges from our approach is the existence of scaling behaviors without fixed or pseudo-fixed point and that relies on a slowing-down of the renormalization group flow in a whole region in the coupling constants space. This phenomenon allows to explain the occurence of generic weak first order behaviors and to understand the absence of universality in the critical behavior of frustrated magnets.Comment: 58 pages, 15 PS figure

Incidence, patterns and severity of reported unintentional injuries in Pakistan for persons five years and older: results of the National Health Survey of Pakistan 1990–94

<p>Abstract</p> <p>Background</p> <p>National level estimates of injuries are not readily available for developing countries. This study estimated the annual incidence, patterns and severity of unintentional injuries among persons over five years of age in Pakistan.</p> <p>Methods</p> <p>National Health Survey of Pakistan (NHSP 1990–94) is a nationally representative survey of the household. Through a two-stage stratified design, 18, 315 persons over 5 years of age were interviewed to estimate the overall annual incidence, patterns and severity of unintentional injuries for males and females in urban and rural areas over the preceding one year. Weighted estimates were computed adjusting for complex survey design using <it>surveyfreq </it>and <it>surveylogistic </it>option of SAS 9.1 software.</p> <p>Results</p> <p>The overall annual incidence of all unintentional injuries was 45.9 (CI: 39.3–52.5) per 1000 per year; 59.2 (CI: 49.2–69.2) and 33.2 (CI: 27.0–39.4) per 1000 per year among males and females over five years of age, respectively. An estimated 6.16 million unintentional injuries occur in Pakistan annually among persons over five years of age. Urban and rural injuries were 55.9 (95% CI: 48.1–63.7) and 41.2 (95% CI: 32.2–50.0) per 1000 per year, respectively. The annual incidence of injuries due to falls were 22.2 (95% CI: 18.0–26.4), poisoning 3.3 (95%CI: 0.5–6.1) and burn was 1.5 (95%CI: 0.9–2.1) per 1000 per year. The majority of injuries occurred at home 19.2 (95%CI: 16.0–22.4) or on the roads 17.0 (95%CI: 13.8–20.2). Road traffic/street, school and urban injuries were more likely to result in handicap.</p> <p>Conclusion</p> <p>There is high burden of unintentional injuries among persons over five years of age in Pakistan. These results are useful to plan further studies and prioritizing prevention programs on injuries nationally and other developing countries with similar situation.</p

Cross-amplification of EST-derived markers among 16 grass species

The availability of a large number of expressed sequence tags (ESTs) has facilitated the development of molecular markers in members of the grass family. As these markers are derived from coding sequences, cross-species amplification and transferability is higher than for markers designed from genomic DNA sequences. In this study, 919 EST-based primers developed from seven grass species were assessed for their amplification across a diverse panel of 16 grass species including cereal, turf and forage crops. Out of the 919 primers tested, 89 successfully amplified DNA from one or more species and 340 primers generated PCR amplicons from at least half of the species in the panel. Only 5.2% of the primers tested produced clear amplicons in all 16 species. The majority of the primers (66.9%) were developed from tall fescue and rice and these two species showed amplification rate of 41.6% and 19.0% across the panel, respectively. The highest amplification rate was found for conserved-intron scanning primers (CISP) developed from pearl millet (91%) and sorghum (75%) EST sequences that aligned to rice sequences. The primers with successful amplification identified in this study showed promise in other grass species as demonstrated in differentiating a set of 13 clones of reed canary grass, a species for which very little genomic research has been done. Sequences from the amplified PCR fragments indicated the potential for the transferable CISP markers for comparative mapping purposes. These primer sets can be immediately used for within and across species mapping and will be especially useful for minor grass species with few or no available molecular markers

Southeast Asia and the Politics of Vulnerability

The economic and political crises that have recently engulfed the countries of Southeast Asia provide a stark reminder of just how difficult the challenge of sustained regional development remains. In retrospect, the hyperbole that surrounded the 'East Asian miracle' looks overblown, and testimony to the manner in which rhetoric can outstrip reality, especially in the minds of international investors. Certainly, some observers had questioned the depth and resilience of capitalist development in Southeast Asia, but in the years immediately prior to 1997 such analyses tended to be in the minority. Now, of course, it is painfully obvious that much of Southeast Asia's economic and political development was extremely fragile. When seen in historical context, this outcome should not have been surprising since the countries of modern Southeast Asia, both as independent nations and as colonies of various imperial powers, have been highly vulnerable to the actions of powerful external political and economic forces. This paper will examine the economic bases and the political consequences of this vulnerablity, both domestically and at a regional level. I argue that the recent crisis has served as an unwelcome reminder of just how constrained, dependent and vulnerable the Southeast Asia region's development prospects remain, a situation that is exacerbated by, and which contributes to, domestic political crises

Financial fragmentation and SMEs’ access to finance

This paper focuses on the impact of financial fragmentation on small and medium enterprises (SMEs)’ access to finance. We combine country-level data on financial fragmentation and the ECB’s SAFE (Survey on the Access to Finance of Enterprises) data for 12 European Union (EU) countries over 2009-2016. Our findings indicate that an increase in financial fragmentation not only raises the probability of all firms to be rationed but also to be charged higher loan rates; in addition, it increases the likelihood of borrower discouragement and it impairs firms’ perceptions of the future availability of bank funds. Less creditworthy firms are even more likely to become credit rationed, suggesting a flight to quality effect in lending. However, our study also documents a potential adverse effect of increasing bank market power resulting from greater integration. This suggests that financial integration could impair firms’ financing, if not accompanied by policy initiatives aimed at maintaining an optimal level of competition in the banking sector