Image guidance and improved accuracy of external ventricular drain tip position particularly in patients with small ventricles.

OBJECTIVE External ventricular drain (EVD) insertion is one of the most common emergency neurosurgical procedures. EVDs are traditionally inserted freehand (FH) in an emergency setting, but often result in suboptimal positioning. Image-guided surgery (IGS) is selectively used to assist placement. However, the accuracy and practicality of IGS use is yet to be reported. In this study, the authors set out to assess if IGS is practical and improves the accuracy of EVD placement. METHODS Case notes and images obtained in patients who underwent frontal EVD placement were retrospectively reviewed. Ventriculomegaly was determined by the measurement of the Evans index. EVD location was classified as optimal (ipsilateral frontal horn) or suboptimal (any other location). Propensity score matching of the two groups (IGS vs FH) for the Evans index was performed. Data were analyzed for patient age, diagnosis, number of EVDs, and complications. Those without postoperative CT scans were excluded. RESULTS A total of 607 patients with 760 EVDs placed were identified; 331 met inclusion criteria. Of these, 287 were inserted FH, and 44 were placed with IGS; 60.6% of all unmatched FH EVDs were optimal compared with 75% of the IGS group (p = 0.067). The IGS group had a significantly smaller Evans index (p < 0.0001). Propensity score matching demonstrated improved optimal position in the IGS group when compared with the matched FH group (75% vs 43.2%, OR 4.6 [1.5-14.6]; p = 0.002). Patients with an Evans index of ≥ 0.36 derived less benefit (75% in IGS vs 66% in FH, p = 0.5), and those with an Evans index < 0.36 derived more benefit (75% in IGS vs 53% in FH, p = 0.024). The overall EVD complication rate was 36% in the FH group versus 18% in the IGS group (p = 0.056). Revision rates were higher in the FH group (p = 0.035), and the operative times were similar (p = 0.69). Long intracranial EVD catheters were associated with tip malposition irrespective of the group. CONCLUSIONS Image guidance is practical and improves the accuracy of EVD placement in patients with small ventricles; thus, it should be considered for these patients

Deformed Statues of Ramses II: a Study of Disruptive Restorations in Egypt in the 21st Century

The research paper discusses the problem of distorting the body proportions in Ramses II statues during the inadequate restoration operations carried out in the 21st century in Egypt. It also discusses the correct artistic body proportions and formation of Ramses II, which must be followed when assembling and restoring statues depicting this figure, at the same time taking into consideration other, unrestored statues, reliefs and paintings of the same subject. In addition, it looks at global restoration technologies that can help to solve the problem of improper restoration in Egypt.L’articolo tratta il problema della distorsione delle proporzioni del corpo nelle statue di Ramses II durante le inadeguate operazioni di restauro effettuate nel 21° secolo in Egitto. Si discute anche delle corrette proporzioni del corpo nell’arte e delle caratteristiche di Ramses II, che devono essere rispettate quando si assemblano e si restaurano le statue che lo raffigurano, tenendo allo stesso tempo in considerazione altre statue, rilievi e dipinti dello stesso soggetto non restaurati. Inoltre, si esaminano le tecnologie di restauro a livello mondiale che possono aiutare a risolvere il problema dei restauri non corretti effettuati in Egitto

SUSTAINABILITY PRACTICES IN FACILITY MANAGEMENT

Facilities management (FM) has witnessed a pragmatic growth and its importance has increased parallel to the expansion of the construction sector. Meanwhile, the concept of sustainability is being established and is considered an essential topic nowadays. Sustainability standards and accreditations are adapted now to design and erect buildings; however, this will not ensure building efficiency during the building’s life cycle. Integration between facility management and sustainability practices should take place in order to raise a building’s performance and achieve energy conservation throughout the building’s operation. Although much research has been conducted in sustainability, very little researches have investigated the topic of sustainability in facility management. The rational of this study is to get a more thorough understanding of facility management practices and sustainability strategies adopted by different FM departments in Qatar. This research could be considered as the basis for FM research because no such previous research is available for Qatar. Moreover, this study aims to investigate and analyze energy consumption, FM practices, and users’ satisfaction through several case studies in FM educational campuses in Qatar. The first objective of this study is to conduct a comprehensive review of existing FM sustainability plans, strategies and practices on various educational campuses in Qatar by numerous cascading levels of stakeholders; starting from FM managers, engineers, technicians and finishing with users. The second objective is to investigate the knowledge of FM teams regarding sustainability concerns and practices. The third objective is to analyze energy consumption data for different buildings across multiple campuses in Qatar and benchmark them with ones abroad to evaluate energy performance for Qatari campuses. The last objective is to propose sustainable practices that could be implemented to reduce energy consumption during building operation. The methodology that is adapted to collect data for this study consists of qualitative and quantitative methods. The interviews represent the qualitative methods and the survey- questionnaire represents the quantitative method. Moreover the energy consumption data analysis is classified under the quantitative part. The energy consumption was collected for different ten buildings as case studies inside Qatar educational campuses and was analyzed to benchmark them with other broad campuses. Moreover the electricity consumption was benchmarked with Energy star standards for educational campuses in order to give a full image about electricity consumption pattern. Interviews were conducted with 20 participants and 105 participants had filled the survey – questionnaire. The results that were concluded from the interviews and surveys were convergent showing that FM teams lack sustainability training. Sustainability practices are not well understood and implemented by FM departments except planned preventive maintenance that is implemented with a high consideration in campuses and it supports energy conservation. Users’ satisfaction regarding services was good, but was not adequate regarding indoor air temperatures as a lot of users are feeling cold and uncomfortable. An energy consumption analysis was done too and it revealed a continuous increase in energy consumption as the number of occupants is increasing and this is pointing out the need to consider sustainability practices. The main results showed that although the EUI value for the case studies is meeting the energy star standards for most of the buildings, compared to broad campuses Qatar campuses are consuming much more electricity so the results of EUI is not accurately representing energy performance. This was more apparent since benchmarking of buildings abroad was studied in terms of consumption per occupant. To get more accurate results on energy performance patterns, the consumption per occupant was calculated for all of the studied buildings and benchmarked with campus buildings in other countries. The results showed that the consumption per occupant in Qatar is 1.5-2 times more than broad campuses. The results of the study found that energy consumption for classroom buildings and office buildings is the same, although building types and functions are different. The type of HVAC system is highly effecting energy consumption , it was found that HVAC with DX system is consuming 4-5 more times that the district cooling system which needs to be taken into consideration in future projects and studies could be conducted to investigate the feasibility of changing the current DX in to other energy saving systems

The connectedness and hedging between gold and Islamic securities in the short, medium and long term

This paper investigates the dynamic connectedness between gold, sukuk and Islamic equities at multiple investment horizons, it also computes optimal hedge ratios and portfolio weights for these assets. Our findings suggest that gold hedges the risk of sukuk in the short and medium terms. We find also that gold plays an average but stable role in hedging and diversifying Islamic equities across all investment horizons. Moreover, we find that gold–Islamic assets portfolio provided a better risk diversification in the short term. These empirical findings are important as they highlight the role of gold in diversifying and managing the risks of portfolios that invest in Islamic assets

The co-movement between oil and clean energy stocks: A wavelet-based analysis of horizon associations

The production of clean energy is crucial for protecting the environment and satisfying the future demand for energy. However, the growth in clean energy production and consumption is influenced by the developments in the oil and the clean energy technology markets. Thus, it is crucial to study the association among these markets and this is the main objective of this research. Compared to the existing literature, we provide evidence from multiple time horizons. In particular, we combine wavelets over various time scales with multivariate GARCH (MGARCH) to find significant bidirectional return and risk transfer from oil and technology to the clean energy market. The transmissions are found to be more pronounced at longer time horizons. These results highlight the importance of certainty and stability in the oil and technology markets for the growth of clean energy particularly in the long term

Total Factor Productivity and Idiosyncratic Volatility Trends

Firms’ idiosyncratic stock return volatility has become more volatile in the US since the 1960s. This paper investigates why individual stocks became more volatile over the 1964–2013 period using firm-level total factor productivity (TFP). On average, the volatility of idiosyncratic TFP growth rate has increased, being associated with higher idiosyncratic return volatility. The connection between TFP growth and economic profits provides an explanation for the increase in the idiosyncratic volatility of fundamental cash flows. The results are robust when using timeseries and panel regressions and controlling for cash flow and earnings variability, size, book-to-market, leverage, profitability, age, dividend yield, and stock illiquidity

The effects of investor emotions sentiments on crude oil returns: A time and frequency dynamics analysis

In this paper, we use wavelet coherence analysis to find that sentiment has a significant effect on crude oil returns that lasts over various investment horizons. While oil returns are positively associated with the sentiments of optimism and trust, it is negatively linked to fear and anger. These relations are more pronounced over the medium and the long term. Additionally, we find that short-term oil returns are relatively more sentiment-sensitive during turbulent periods than in normal conditions. These results highlight the importance of sentiment and investor psychology in the crude oil market

Long-Run Performance of Redeemable Convertible Unsecured Loan Stocks (RCULS) and Irredeemable Convertible Unsecured Loan Stocks (ICULS)

This study examines the long-run performance of Redeemable Convertible Unsecured Loan Stocks (RCULS) and Irredeemable Convertible Unsecured Loan Stocks (ICULS). Using the monthly data on corporations listed on the Main Board, Bursa Malaysia, that issued the RCULS and ICULS; buy-and-hold abnormal returns (BHAR) and cumulative abnormal returns (CAR) methods are conducted to examine the long - run performance of the two instruments. The findings and analysis of this thesis were made based on the data collected from Bursa Malaysia Bloomberg and Investor's Digest and Datastream. The results indicate that overperformance exists on the issuing firms1 stock returns for all one - year, two - year and three - year periods, regardless whether buy-and-hold abnormal returns (BHAR) or cumulative abnormal returns (CAR) is applied. Although, the results do contra with Gompers and Lemer (2003), Ritter and Welch (2002), Loughran and Ritter (1995) and Loughran (1993). the argument is based on the sample size being used in the study

INVESTIGATION OF LOADED FIBROUS FILTER

This paper presents results of theoretical and experimental investigations of the effect of dust deposition on filter performance. In the theoretical model, the filter is divided into elements of various structural characteristics and the effect of fibers and deposited particles on pressure drop and collection efficiency is considered. In the suggested model, the part of the deposited particles increases the diameter of fibers, the rest form dendrites. Two dimensional flow fields in inhomogeneous filter mat are described by the continuity equation and Darcy equation. In order to obtain a clear idea about the effect of dust load on pressure drop and filter efficiency experimental investigations of clogging process in filter mats were performed where the temporal change of pressure drop and grade efficiency were measured. Theoretical and experimental results indicate that due to deposited particles the collection efficiency of filters increases rather rapidly with loading because the previously deposited particles offer additional collection surface. Deposited particles increase also the pressure drop across the filter by additional drag to gas flow. Calculations of streamlines through inhomogeneous filter mat indicate that deposited particles increase the uniformity of the flow field. The comparison of the results of calculation and experimental data on temporal change of collection efficiency and pressure drop shows considerable agreement