Improved Methods for Fluorescence Microscopy Detection of Macromolecules at the Axon Initial Segment

The axonal initial segment (AIS) is the subcellular compartment required for initiation of the action potential in neurons. Scaffolding and regulatory proteins at the AIS cluster with ion channels ensuring the integrity of electrical signaling. Interference with the configuration of this protein network can lead to profound effects on neuronal polarity, excitability, cell-to-cell connectivity and brain circuit plasticity. As such, the ability to visualize AIS components with precision provides an invaluable opportunity for parsing out key molecular determinants of neuronal function. Fluorescence-based immunolabeling is a sensitive method for morphological and molecular characterization of fine structures in neurons. Yet, even when combined with confocal microscopy, detection of AIS elements with immunofluorescence has been limited by the loss of antigenicity caused by fixative materials. This technical barrier has posed significant limitations in detecting AIS components alone or in combination with other markers. Here, we designed improved protocols targeted to confocal immunofluorescence detection of the AIS marker fibroblast growth factor 14 (FGF14) in combination with the cytoskeletal-associated protein Ankyrin-G, the scaffolding protein βIV-spectrin, voltage-gated Na+ (Nav) channels (especially the Nav1.6 isoform) and critical cell type-specific neuronal markers such as parvalbumin, calbindin, and NeuN in the mouse brain. Notably, we demonstrate that intracardiac perfusion of animals with a commercially available solution containing 1% formaldehyde and 0.5% methanol, followed by brief fixation with cold acetone is an optimal and sensitive protocol for FGF14 and other AIS marker detection that guarantees excellent tissue integrity. With variations in the procedure, we also significantly improved the detection of Nav1.6, a Nav isoform known for its fixative-sensitivity. Overall, this study provides an ensemble of immunohistochemical recipes that permit excellent staining of otherwise invisible molecules within well-preserved tissue architecture. While improving the specific investigation of AIS physiology and cell biology, our thorough study can also serve as a roadmap for optimizing immunodetection of other fixative-sensitive proteins expanding the repertoire of enabling methods for brain studies

Some factors affecting dairy she-camel performance

In order to determine the effect of some factors, as different levels of energy and protein, milking interval, lactation stage, and lactation rank on she-camel performance after weaning of camel-calves, 20 lactating shecamels were divided into four groups, 5 animals each, according to age and weight at last parturition. Groups had randomly allocated to one of four treatments diets. Group A received diet with 13% Crude Protein (CP) and 2.4 MCal Metabolisable Energy (ME). Group B received diet with 13% CP and 3.0 MCal ME. Group C and D received diet with 15% CP and 2.4, 3.0 MCal ME respectively. Diets contain 35/65 (roughage/concentrate, respectively). After 14 days of adaptation period, individual feed offered and orts had been recorded, daily and continued up to entire experimental period of 10 months. Milk yield was recorded two milking time from three consecutive days. The results show that diet (B) gave higher milk yield (MY), Fat Corrected Milk (FCM), Energy Corrected Milk (ECM) and Feed Conversion Ratio (FCR) 8.32, 11.77, 7.47, and 1.38 respectively. Diet (A) has higher fat % content when comparing with the other diets. Treatment did not affect milk composition except on fat and ash percentage. Milk secretion rate for 10 hours milking interval "evening milking" was higher comparing with 14 hours milking interval "morning milking" 397, 353 g/h respectively. Maximum MY, FCM and ECM were at mid lactation. In late lactation MY, FCM, ECM decreased. Higher milk productivity was at 3rd and 6th season of lactation. (Résumé d'auteur

Effect of different feeding regime on body weight, ovaries sïze fevelopments and blood estradiol, progesterone level in pre-pubertal she-camel (Camelus dromedarius)

The present study aimed ta investigate the effect of nutrition on body weight gain, avaries development, blood components (total protein, alblllllen, globulin, cholesterol and glucose) and hormone level (estradiol and progesterone) in pre-pubertal she-camels. Fourteen dromedary she-camels (Camelus dromedarius) were divided in two groups CA and B) similar body weight and age ai the siart of the experiment (200 kg and 12 month, respectively). Group A received diet with 13% Crude Protein (CP) and 2.9 Meal Metabolisable Energy (ME). Group B received the traditional diet of the fann. Both diets contained 25:75 forage:concentrate. Individual feed intake was calculated after 14 days of adaptation period. Feed offered and arts was recorded daily during the whole experimental period of 12 months. Blood samples were taken from each group every 15 days throughout the experimental period. Estradiol, progesterone concentrations were measured using ELISA kits. Body weight and average daily gain for the Ist 6 months did not show significant differences between treatments. On the contrary for the last 6 months, treatment A significantly increased body weight and daily weight gain when compared to B (70.07±8.17 kg and 0.389±0.05 kg day-' vs. 37.86±8.17 kg and 0.210±O.05 kg day-l, respectively. Group A was more efficient converting feed to body weight comparing with group B. Feed Conversion Ratio (FCR) for the whole period was 11.25 and 13.74 for Group A and B, respectively. Group B had greater ovary size than Group A but the difference was not significant. Size of right ovary was smaller than the left one and season had positive effects on both right and left ovary sizes. Greater ovary sizes were observed in Winter and Spring comparing with Swnmer and Autumn. Group A had higher blood estradiollevel comparing with Group B while there was no difference between groups in progesterone levels. Il was concluded that feeding regirne did not affect body weight, daily body weight gain and blood progesterone levels but improved feed conversion ratio and blood estrogen levels. (Résumé d'auteur

Effect of different feeding system on body weight, testicular size developments, and testosterone level in pre-pubertal male camel (Camelus dromedarius)

Eighteen dromedary males (Camelus dromedarius) were used to investigate the effect of nutrition on body weight, size of the testes, and blood testosterone concentrations in pre-pubertal male camels. Animals were divided into two groups of 9 animals each. Group A received a diet with 13% crude protein (CP) and 2.9 MCal (ME), whereas Group B received the traditional diet of the farm, and each animals' feed intake was calculated after allowing a 14 day adaptation period. Diets contain 25:75 (roughage: concentrate, respectively). Blood samples were taken from the same five animals from each group, every 15 days during the whole experimental period and plasma testosterone concentrations were measured. There was no significant difference in total body weight gain over the whole experimental period between Group A and B, although Group A showed a significant increase in body weight over the last 6 months compared with Group B. Group A consumed less feed and were more efficient at converting feed to body weight than Group (B), as shown by the (FCR) over the whole period which was 9.25 for Group A and 13.03 for Group B. There was no significant difference in testicle size between Groups A and B at the start of the experimental period, blood testosterone levels were significantly higher in Group A compared with Group B, but although there was an increase in testicle size over the experimental period, there was no significant increase in blood testosterone levels. (Résumé d'auteur

The Falling Dollar and Its Impact on the Saudi Economy

As foreign exchange studies show, after a fairly strong performance in 2014, the US Dollar (USD) plunged in 2015 in relation to the Euro, British Pound, Japanese Yen, and other global currencies (US Forex 2015). While the trend on US currency fall similarly happened in the past, the weak global confidence now on the US economy has cast serious apprehension on the prospect for any renewed global economic stability. Whenever the USD, as central world currency, declines or appreciates significantly in value, the change impacts the economies of most nations around the world (Amadeo 2015).  One of the countries that stand most vulnerable to any serious and unwanted dysfunction of the USD is Saudi Arabia, which, as a matter of key economic policy, has fixed its currency exchange to Saudi Arabia Riyals (SAR) 3.75 to USD 1.00 since 1986 (Al-Hamidy 2013).  This paper aims at Highlighting the risks of devaluation of the dollar on the Saudi economy There are seven sections in the paper after the introduction. In sections two The changing price of gold and oil in term of USD…; section three The Impacts of fixed exchange rate on the Saudi Economy …;The rationale and implication for the fixed rate,  Policy measures to overcome the risk caused by the depreciation of USD…Possible Policy Options in the Short…, and in the last section Concluding Remarks…

Outward FDI and Domestic Investment: Evidence from World’s Largest Economies

This study provides empirical evidence of the impacts of FDI outflows on domestic investment in the world’s largest economies using panel data analysis. Our estimates using system-Generalized Method of Moments (GMM) suggest that FDI outflows have positive effects on domestic investment. From 2002-2014, OFDI had significant long-term effects on domestic investment among the world’s largest economies. Our system-GMM model results show that a one dollar increase in OFDI leads to an increase of 0.0894 dollars of domestic investment in the long term. Keywords: Outward FDI; Domestic investment; Endogeneity; Panel Data JEL Classification numbers: C23; F21; F22; F2

The Long-Run Effect of Outward Foreign Direct Investment and Macroeconomic Variables on Domestic Investment: Evidence from World Major Economies Using Panel ARDL Approach

In this paper, we investigate relationship between outward foreign direct investment flows and domestic investment among thirteen world major economies over time period 1970-2013. From 1970-2013, had outward foreign direct investment flows along with macroeconomic control variables had significant long-term effects on domestic investment among world major economies. Following the latest dynamic techniques of panel data analysis of pooled mean group and dynamic fixed effect estimators proposed by Pesaran et al. (1999), we find strong evidence of positive impact of outward foreign direct investment flows on domestic investment. Pooled mean group estimator results show that one dollar increase in foreign direct investment outflows result in increase of Domestic investment by 0.49 dollars. Dynamic fixed effect result findings also strongly support positive impact of foreign direct investment outflows on domestic investment .i.e. (one dollar increase in foreign direct investment outflows result in increase of domestic investment by 0.87 dollars).Our result findings confirm that foreign direct investment outflows along with  macroeconomic control variables have positive and significant impact on domestic investment. Dumitrescu Hurlin Panel Causality test results show that there is pairwise causality running between the variables. Keywords: Outward FDI; Domestic investment; Cointegration; Panel Dat

The Long-Run Effect of FDI Inflows on Total Factor Productivity: Evidence from African Countries

From 2001-2014, had foreign direct investment inflows had significant long-term effects on total factor productivity in African countries. Following the latest dynamic techniques of panel data analysis of pooled mean group and mean group estimator (the Pesaran and Smith 1995, Journal of Econometrics 68: 79-113), we find strong evidence of insignificant impact of FDI inflows on total factor productivity. Augmented mean group estimator(AMG) introduced by Eberhardt and Teal (2010, Discussion Paper 515, Department of Economics, University of Oxford) and the Pesaran (2006,Econometrica 74: 967-1012) common correlated effects mean group estimator results also strongly support insignificant impact FDI inflows on total factor productivity in the long run in African economies. Augmented mean group estimator, common correlated effects mean group estimator and pooled mean group estimator result findings show that covariates or control variables (Trade and Domestic investment) have significant effects on total factor productivity in the long run. The result findings show that covariates or control variables are important determinants (factors) in defining exact relationship between FDI inflows and total factor productivity. Keywords: FDI inflows; Total Factor Productivity; Panel Data; Economic growth JEL Classification numbers: C33; F21; F2

Inward FDI, Outward FDI and Domestic Investment: Evidence from Asian Economies Using Panel Data Analysis

This study measures effects of FDI inflows and outflows on domestic investment in Asian economies using panel data analysis. Our estimates using system-Generalized Method of Moments (GMM) suggest that FDI inflows (IFDI) have positive and significant effects on domestic investment but outward FDI (OFDI) is negatively associated with domestic investment. From 2004-2014, OFDI and IFDI had significant long-term effects on domestic investment among the Asian economies. Our system Generalized Method of Moments (GMM) model results show that one dollar increase in FDI inflows leads to increase domestic investment by 0.3081 dollars. Our system Generalized Method of Moments (GMM) model results show that one dollar increase in FDI outflows leads to decrease domestic investment by 0.2704 dollars. Our result findings are robust with different econometric techniques measuring effects of inward FDI and outward FDI on domestic investment among Asian economies. Keywords: FDI inflows; FDI outflows; Domestic investment; Endogeneity; Panel Data JEL Classification numbers: C23; F21; F22; F2