Can hydrogen sulfide prevent preeclampsia and fetal growth restriction?

The exact aetiology of preeclampsia is unknown, but there is a good association with an imbalance in angiogenic growth factors and abnormal placentation [1]. Hydrogen sulphide (H2S), a gaseous messenger produced mainly by cystathionine γ-lyase (CSE), is pro-angiogenic vasodilator [2] and [3]. We hypothesized that a reduction in CSE activity may alter the angiogenic balance in pregnancy and induce abnormal placentation and maternal hypertension. Plasma levels of H2S were significantly decreased in preeclamptic women (p < 0.01), which was associated with reduced CSE message and protein expression in human placenta as determined by real-time PCR and immunohistochemistry. Inhibition of CSE activity by DL-propargylglycine (PAG) in first trimester (8–12 weeks gestation) human placental explants had reduced placenta growth factor (PlGF) production as assessed by ELISA and inhibited trophoblast invasion in vitro. Endothelial CSE knockdown by siRNA transfection increased the endogenous release of soluble fms-Like tyrosine kinase-1 (sFlt-1) and soluble endoglin, (sEng) from human umbilical vein endothelial cells while adenoviral-mediated CSE overexpression inhibited their release. Administration of PAG to pregnant mice induced hypertension, liver damage, and promoted abnormal labyrinth vascularisation in the placenta and decreased fetal growth. Finally, a slow releasing, H2S-generating compound, GYY4137, inhibited circulating sFlt-1 and sEng levels and restored fetal growth that was compromised by PAG-treatment demonstrating that the effect of CSE inhibitor was due to inhibition of H2S production. These results imply that endogenous H2S is required for healthy placental vasculature and a decrease in of CSE/H2S activity may contribute to the pathogenesis of preeclampsia. References [1] S. Ahmad, A. Ahmed, Elevated placental soluble vascular endothelial growth factor receptor-1 inhibits angiogenesis in preeclampsia, Circ Res., 95 (2004), pp. 884–891. [2] G. Yang, et al., H2S as a physiologic vasorelaxant: hypertension in mice with deletion of cystathionine gamma-lyase, Science, 322 (2008), pp. 587–590. [3] A. Papapetropoulos, et al., Hydrogen sulfide is an endogenous stimulator of angiogenesis, Proc Natl Acad Sci USA, 106 (2009), pp. 21972–21977.

Determinants of Firm Growth with respect to Exporting and Innovation Activities: Evidence from Egyptian SMEs

Small and medium-sized enterprises (SMEs) are considered to be the driving engine for employment growth, source of innovation and technological progress. Moreover, the success of small exporters is critical for economic growth and is considered as an important development stage for many SMEs. However, their competitive advantage lies within the firm’s ability to innovate. This thesis contributes to the above literature by examining two main factors believed to promote firm growth namely ‘exporting’ and ‘innovation’ activities. Growing interests on the relationship between exporting, innovation and growth have recently been tackled. However, there remains a gap in literature on the relationship between exporting, innovation and firm growth for SMEs in emerging economies. Previous studies are conducted in developed counties such as UK, Ireland, USA, Germany, and Switzerland, which leaves the gap for those developing countries. Thus, this thesis addresses the gap by examining the importance of innovation and exporting activities in the growth of SMEs in Egypt. It is also the researcher’s intent to recognise the unique contribution of innovation on firm exporting activities covering all sectors. gypt, one of the countries that were tremendously affected by the so-called ‘Arab Spring revolution’, is suffering from slow economic growth, high unemployment and poverty rate. Thus, the government must ensure economic growth and job creation. Programmes to encourage and develop SMEs should be part of inclusive growth strategy. Meanwhile, exporting is regarded as a key factor to help the economy recover from recession and stimulate economic growth. On the other hand, innovation leads to better performance in terms of growth, exporting and productivity. Therefore, SMEs and their exporting and innovation activities should be an integral part of any recovery and growth strategy for the economy. Moreover, Egypt is suffering from the so-called ‘Missing Middle’, which is problematic as medium firms tend to provide better employment growth and productivity. Therefore, more light is to shed on the importance of exporting and innovation in the growth of firms. The research design was quantitative in nature, testing the proposed hypotheses. The study was conducted in 2013 based on questionnaires of 406 Egyptians SMEs. The results of the empirical study suggest that both exporting and innovation activities are important in firm growth. However, the results show that, after controlling for endogeneity, innovation does not affect exporting activities in SMEs.

Determinants of firm growth with repect to exporting and innovation activities:evidence from Egyptian SMEs

Small and medium-sized enterprises (SMEs) are considered to be the driving engine for employment growth, source of innovation and technological progress. Moreover, the success of small exporters is critical for economic growth and is considered as an important development stage for many SMEs. However, their competitive advantage lies within the firm’s ability to innovate. This thesis contributes to the above literature by examining two main factors believed to promote firm growth namely ‘exporting’ and ‘innovation’ activities. Growing interests on the relationship between exporting, innovation and growth have recently been tackled. However, there remains a gap in literature on the relationship between exporting, innovation and firm growth for SMEs in emerging economies. Previous studies are conducted in developed counties such as UK, Ireland, USA, Germany, and Switzerland, which leaves the gap for those developing countries. Thus, this thesis addresses the gap by examining the importance of innovation and exporting activities in the growth of SMEs in Egypt. It is also the researcher’s intent to recognise the unique contribution of innovation on firm exporting activities covering all sectors. Egypt, one of the countries that were tremendously affected by the so-called ‘Arab Spring revolution’, is suffering from slow economic growth, high unemployment and poverty rate. Thus, the government must ensure economic growth and job creation. Programmes to encourage and develop SMEs should be part of inclusive growth strategy. Meanwhile, exporting is regarded as a key factor to help the economy recover from recession and stimulate economic growth. On the other hand, innovation leads to better performance in terms of growth, exporting and productivity. Therefore, SMEs and their exporting and innovation activities should be an integral part of any recovery and growth strategy for the economy. Moreover, Egypt is suffering from the so-called ‘Missing Middle’, which is problematic as medium firms tend to provide better employment growth and productivity. Therefore, more light is to shed on the importance of exporting and innovation in the growth of firms. The research design was quantitative in nature, testing the proposed hypotheses. The study was conducted in 2013 based on questionnaires of 406 Egyptians SMEs. The results of the empirical study suggest that both exporting and innovation activities are important in firm growth. However, the results show that, after controlling for endogeneity, innovation does not affect exporting activities in SMEs.

A sikeres növekedés és innováció feltételei (The condition of successful growth and innovation)

Kutatásukban a szerzők a sikeres innovációs-növekedési stratégiák beazonosítására törekedtek két dimenzió mentén: növekedési erőfeszítés és innovációs erőfeszítés. A sikert mint a radikális innováció piaci bevezetéseként definiálták. A szakirodalom áttekintése és kvalitatív kutatási eredményeink alapján azt találták, hogy a siker feltételei a következők: (1) „felkészültség”, azaz biztos szakmai tudás (know-what); a (2) „gyakorlás”, azaz a folyamatok tökéletes ismerete (know-how); a (3) „tehetséggondozás”, azaz a megfelelő kapcsolati tőke a hiányzó képességek, erőforrások és információk megszerzéséhez (know-who); és végül a (4) „tehetség”, azaz kreativitás, magas asszociációs készség, és innovatív ötletek. A vezető feladata annak felismerése, hogy mikor szükséges lassítania a szervezetre nehezedő növekedési nyomáson. A nyugalmi időszakban továbbra is fontos az innovációs képességek fejlesztése. Következetesen fel kell ismernie, hogy mikor lesz nagyobb a szétaprózott erőforrások és a megosztott figyelem költsége, mint a potenciális hozadéka. _______ In present research the successful innovation-growth strategies are identified along two dimensions: growth effort and innovation effort. The success is defined as the introduction to the market of a radical innovation. After reviewing the literature and conducting a qualitative research, authors found that the threshold condition of success are the followings: (1) “preparation”, that is expertise (know-what); (2) “practice”, that is deep understanding of processes (know-how); (3) “talent support”, that is access to missing resources; and finally (4) “talent”, that is creativity, innovative idea, and high association capability. This is the role of the manager to decide when the organizational growth should be slowed down. While the development of innovation capability is still important in times of slow growth periods, the manager must recognize that the cost of divided attention and fragmented resources is higher, than the potential return of the innovation.

Essays on investment, growth and income distribution

In this dissertation, I examine both theoretically and empirically the relationship between stock prices and income distribution using an endogenous growth model with social status impatience.^ The theoretical part looks into how status impatience and current economic status jointly determine time preference, savings, future economic status, stock prices, growth and wealth distribution in the steady state. This work builds on Burgstaller and Karayalcin (1996).^ More specifically, I look at (i) the effects of the distribution of status impatience levels on the distribution of steady state assets, incomes and consumption and (ii) the effects of changes in relative levels of status impatience on stock prices. Therefore, from (i) and (ii), I derive the correlation between stock prices, incomes and asset distribution. Also, the analysis of the stack market is undertaken in the presence of adjustment costs to investments.^ The empirical chapter looks at (i) the correlation between income inequality and long run economic growth on the one hand and (ii) the correlation between stock market prices and income inequality on the other. The role of stock prices and social status is examined to better understand the forces that enable a country to grow overtime and to determine why output per capita varies across countries. The data are from Summers and Heston (1988), Barro and Wolf (1989), Alesina and Rodrik (1994), Global financial Database (1997) and the World Bank. Data for social status are collected through a primary sample survey on the internet. Twenty-five developed and developing countries are included in the sample.^ The model developed in this study was specified as a system of simultaneous equations, in which per capita growth rate and income inequality were endogenous variables. Additionally, stock price index and social status measures were also incorporated. The results indicate that income inequality is inversely related to economic growth. In addition, increase in income inequality arising from higher stock prices constrains growth. Moreover, where social status is determined by income levels, it influences long run growth. Therefore, these results support findings of Persson and Tabellini (1994) and Alesina and Rodrik (1994). ^

The effects of climate on the growth and physiology of tropical rainforest trees

Tropical rainforests account for more than a third of global net primary production and contain more than half of the global forest carbon. Though these forests are a disproportionately important component of the global carbon cycle, the relationship between rainforest productivity and climate remains poorly understood. Understanding the link between current climate and rainforest tree stem diameter increment, a major constituent of forest productivity, will be crucial to efforts at modeling future climate and rainforest response to climate change. This work reports the physiological and stem growth responses to micrometeorological and phenological states of ten species of canopy trees in a Costa Rican wet tropical forest at sub-annual time intervals. I measured tree growth using band dendrometers and estimated leaf and reproductive phenological states monthly. Electronic data loggers recorded xylem sap flow (an indicator of photosynthetic rate) and weather at half-hour intervals. An analysis of xylem sap flow showed that physiological responses were independent of species, which allowed me to construct a general model of weather driven sap flow rates. This model predicted more than eighty percent of climate driven sap flow variation. Leaf phenology influenced growth in three of the ten species, with two of these species showing a link between leaf phenology and weather. A combination of rainfall, air temperature, and irradiance likely provided the cues that triggered leaf drop in Dipteryx panamensis and Lecythis ampla. Combining the results of the sap flow model, growth, and the climate measures showed tree growth was correlated to climate, though the majority of growth variation remained unexplained. Low variance in the environmental variables and growth rates likely contributed to the large amount of unexplained variation. A simple model that included previous growth increment and three meteorological variables explained from four to nearly fifty percent of the growth variation. Significant growth carryover existed in six of the ten species, and rainfall was positively correlated to growth in eight of the ten species. Minimum nighttime temperature was also correlated to higher growth rates in five of the species and irradiance in two species. These results indicate that tropical rainforest tree trunks could act as carbon sinks if future climate becomes wetter and slightly warmer. ^

Economic Growth and Recession Time Periods: Their Effect Upon Pleasure Travelers Visiting Florida Theme Parks

Two tourism-oriented travel samples were drawn from recent time periods that represented economic growth (expansion) and recession cycles in the O: S. economy. Analysis suggests that during the recession period, a greater percentage of theme park visitors chose to travel by air. Second, theme park travelers were more likely to visit friends or fami4 during the recession period. Third, recession theme park travelers were 10 years older, on the average, than their rapid growth counterparts. The average age difference of theme park visitors was found to be significantly different during cyclical economic periods. Research findings support the need for additional studies that segment using generational markets

Stoichiometry, growth, and fecundity responses to nutrient enrichment by invertebrate grazers in sub-tropical turtle grass (Thalassia testudinum) meadows

Although the effectiveness of herbivores in mitigating the effects of nutrient enrichment is well documented, few studies have examined the effects of nutrient enrichment on components of consumer fitness. Enclosures were deployed in shallow turtle grass (Thalassia testudinum) beds in Florida Bay, Florida in fall 2003, spring 2004, and fall 2004 to measure the effects of nitrogen and phosphorous enrichment on the growth, fecundity, and stoichiometry of three invertebrate epiphyte grazers commonly associated with T. testudinum. The gastropod Turbo castanea exhibited significantly greater wet weight gain and lower C:P and N:P in enriched than in ambient treatments. Although nutrient enrichment did not have any significant effects on the growth of caridean shrimp (treatment consisted of several different caridean shrimp species), their C:N was significantly lower in enriched treatments. The final size and stoichiometry of the hermit crab Paguristes tortugae was not significantly affected by nutrient enrichment, nor did nutrient enrichment significantly affect the fecundity of P. tortugae, the only grazer in which gravid individuals or egg masses were present. Our study demonstrated that nutrient enrichment of primary producers can positively affect the growth of marine invertebrate grazers and alter their stoichiometry; however, these effects were species-specific and may be dependent upon the life stage, specific diets, and/or compensatory feeding habits of the grazers.

Defining Fluid Restriction in the Management of Infants Following Cardiac Surgery and Understanding the Subsequent Impact on Nutrient Delivery and Growth Outcomes

Adequacy of nutritional intake during the postoperative period, as measured by a change in weight-for-age z-scores from surgery to the time of discharge, was evaluated in infants (n = 58) diagnosed with a congenital heart defect and admitted for surgical intervention at Miami Children’s Hospital using a prospective observational study design. Parental consent was obtained for all infants who participated in the study. Forty patients had a weight available at hospital discharge. The mean preoperative weight-for-age z-score was -1.3 ±1.43 and the mean weight-for-age z-score at hospital discharge was -1.89 ±1.35 with a mean difference of 0.58 ±0.5 (P Nutritional intake during the postoperative period was inadequate based on a decrease in weight-for-age z-scores from the time of surgery until discharged home. Our findings suggested that limited fluid volume for nutrition likely contributes to suboptimal nutritional delivery during the postoperative period; however, inadequate nutrition prescription may also be an important contributing factor. Development of a nutrition protocol for initiation and advancement of nutrition support may reduce the delay in achieving patient’s nutritional goals and may attenuate the observed decrease in z-scores during the postoperative period.

Experimental results for Ecklonia radiata growth and in situ incubation experiments and in situ measurements of pH within E. radiata beds in south eastern Tasmania

Ocean acidification (OA) is the reduction in seawater pH due to the absorption of human-released CO2 by the world's oceans. The average surface oceanic pH is predicted to decline by 0.4 units by 2100. However, kelp metabolically modifies seawater pH via photosynthesis and respiration in some temperate coastal systems, resulting in daily pH fluctuations of up to ±0.45 units. It is unknown how these fluctuations in pH influence the growth and physiology of the kelp, or how this might change with OA. In laboratory experiments that mimicked the most extreme pH fluctuations measured within beds of the canopy-forming kelp Ecklonia radiata in Tasmania, the growth and photosynthetic rates of juvenile E. radiata were greater under fluctuating pH (8.4 in the day, 7.8 at night) than in static pH treatments (8.4, 8.1, 7.8). However, pH fluctuations had no effect on growth rates and a negative effect on photosynthesis when the mean pH of each treatment was reduced by 0.3 units. Currently, pH fluctuations have a positive effect on E. radiata but this effect could be reversed in the future under OA, which is likely to impact the future ecological dynamics and productivity of habitats dominated by E. radiata.

Short-term metabolic and growth responses of the cold-water coral lophelia pertusa to ocean acidification

Cold-water corals are amongst the most three-dimensionally complex deep-sea habitats known and are associated with high local biodiversity. Despite their importance as ecosystem engineers, little is known about how these organisms will respond to projected ocean acidification. Since preindustrial times, average ocean pH has already decreased from 8.2 to ~ 8.1. Predicted CO2 emissions will decrease this by up to another 0.3 pH units by the end of the century. This decrease in pH may have a wide range of impacts upon marine life, and in particular upon calcifiers such as cold-water corals. Lophelia pertusa is the most widespread cold-water coral (CWC) species, frequently found in the North Atlantic. Data here relate to a short term data set (21 days) on metabolism and net calcification rates of freshly collected L. pertusa from Mingulay Reef Complex, Scotland. These data from freshly collected L. pertusa from the Mingulay Reef Complex will help define the impact of ocean acidification upon the growth, physiology and structural integrity of this key reef framework forming species.

Experimental data on photophysiology and growth rates of the invasive foraminifera Amphistegina lobifera showing high thermal tolerance from the Eastern Mediterranean and the Gulf of Aqaba

Invasive species allow an investigation of trait retention and adaptations after exposure to new habitats. Recent work on corals from the Gulf of Aqaba (GoA) shows that tolerance to high temperature persists thousands of years after invasion, without any apparent adaptive advantage. Here we test whether thermal tolerance retention also occurs in another symbiont-bearing calcifying organism. To this end, we investigate the thermal tolerance of the benthic foraminifera Amphistegina lobifera from the GoA (29° 30.14167 N 34° 55.085 E) and compare it to a recent "Lessepsian invader population" from the Eastern Mediterranean (EaM) (32° 37.386 N, 34°55.169 E). We first established that the studied populations are genetically homogenous but distinct from a population in Australia, and that they contain a similar consortium of diatom symbionts, confirming their recent common descent. Thereafter, we exposed specimens from GoA and EaM to elevated temperatures for three weeks and monitored survivorship, growth rates and photophysiology. Both populations exhibited a similar pattern of temperature tolerance. A consistent reduction of photosynthetic dark yields was observed at 34°C and reduced growth was observed at 32°C. The apparent tolerance to sustained exposure to high temperature cannot have a direct adaptive importance, as peak summer temperatures in both locations remain <32°C. Instead, it seems that in the studied foraminifera tolerance to high temperature is a conservative trait and the EaM population retained this trait since its recent invasion. Such pre-adaptation to higher temperatures confers A. lobifera a clear adaptive advantage in shallow and episodically high temperature environments in the Mediterranean under further warming.

Impact of salinity and growth phase on alkenone distributions in coastal haptophytes

Batch cultures of Isochrysis galbana (strain CCMP 1323) and Chrysotila lamellosa (strain CCMP 1307) were grown at salinity ca. 10 to ca. 35 and the alkenone distributions determined for different growth phases. UK'37 values decreased slightly with salinity for C. lamellosa but were largely unaffected for I. galbana except during the decline phase. The values decreased with incubation time in both species. The proportion of C37:4, used as proxy for salinity, increased in both species at 0.16-0.20% per salinity unit, except during the stationary phase for I. galbana. C37:4 was much more abundant in C. lamellosa (30-44%) than in I. galbana (4-12%). Although our results suggest that salinity has a direct effect on alkenone distributions, growth phase and species composition will also have a marked impact, complicating the use of alkenone distributions as a proxy for salinity in the marine environment.

Insulin-Like Growth Factor-I (IGF-1), IGF-Binding Protein-3 (IGFBP-3) and mammographic features

Introduction. The IGF system has recently been shown to play an important role in the regulation of breast tumor cell proliferation. However, also breast density is currently considered as the strongest breast cancer risk factor. It is not yet clear whether these factors are interrelated and if and how they are influenced by menopausal status. The purpose of this study was to examine the possible effects of IGF-1 and IGFBP-3 and IGF-1/IGFBP-3 molar ratio on mammographic density stratified by menopausal status. Patients and methods. A group of 341 Italian women were interviewed to collect the following data: family history of breast cancer, reproductive and menstrual factors, breast biopsies, previous administration of hormonal contraceptive therapy, hormone replacement therapy (HRT) in menopause and lifestyle information. A blood sample was drawn for determination of IGF-1, IGFBP-3 levels. IGF-1/ IGFBP-3 molar ratio was then calculated. On the basis of recent mammograms the women were divided into two groups: dense breast (DB) and non-dense breast (NDB). Student’s t-test was employed to assess the association between breast density and plasma level of IGF-1, IGFBP-3 and molar ratio. To assess if this relationship was similar in subgroups of pre- and postmenopausal women, the study population was stratified by menopausal status and Student’s t-test was performed. Finally, multivariate analysis was employed to evaluate if there were confounding factors that might influence the relationship between growth factors and breast density. Results. The analysis of the relationship between mammographic density and plasma level of IGF-1, IGFBP-3 and IGF-1/ IGFBP-3 molar ratio showed that IGF-1 levels and molar ratio varied in the two groups resulting in higher mean values in the DB group (IGF-1: 109.6 versus 96.6 ng/ml; p= 0.001 and molar ratio 29.4 versus 25.5 ng/ml; p= 0.001) whereas IGFBP-3 showed similar values in both groups (DB and NDB). Analysis of plasma level of IGF-1, IGFBP-3 and IGF-1/IGFBP-3 molar ratio compared to breast density after stratification of the study population by menopausal status (premenopausal and postmenopausal) showed that there was no association between the plasma of growth factors and breast density, neither in premenopausal nor in postmenopausal patients. Multivariate analysis showed that only nulliparity, premenopausal status and body mass index (BMI) are determinants of breast density. Conclusions. Our study provides a strong evidence of a crude association between breast density and plasma levels of IGF-1 and molar ratio. On the basis of our results, it is reasonable to assume that the role of IGF-1 and molar ratio in the pathogenesis of breast cancer might be mediated through mammographic density. IGF-1 and molar ratio might thus increase the risk of cancer by increasing mammographic density.

Influence of environmental conditions on the age, hatch dates, and growth of juvenile Atlantic menhaden in the Choptank River, MD

Since 1993 Atlantic menhaden has experienced sustained low juvenile production (recruitment) in the Chesapeake Bay. Factors controlling growth, abundance, and mortality of larval and juvenile menhaden change throughout ontogeny such that larval growth rates could carry over to juvenile growth and survival. The effects of winter thermal conditions on the hatch dates and growth of larval and juvenile Atlantic menhaden in Atlantic shelf and Chesapeake Bay habitats were examined using otolith (ear-stone) increment analyses and growth models. For 2010-2013, truncated hatch-date distributions provided evidence for a winter recruitment bottleneck in Atlantic menhaden caused by cold temperatures. Hatch-dates of surviving juveniles were skewed towards warmer months for years characterized by colder temperatures. Reduced larval growth rates, influenced by reduced temperature and food availability, carried over to juvenile growth rates. A growing degree-day model performed well in simulating observed juvenile growth rates in the Choptank River tributary of Chesapeake Bay.