2,725 research outputs found

    Reliability assessment of microgrid with renewable generation and prioritized loads

    Full text link
    With the increase in awareness about the climate change, there has been a tremendous shift towards utilizing renewable energy sources (RES). In this regard, smart grid technologies have been presented to facilitate higher penetration of RES. Microgrids are the key components of the smart grids. Microgrids allow integration of various distributed energy resources (DER) such as the distributed generation (DGs) and energy storage systems (ESSs) into the distribution system and hence remove or delay the need for distribution expansion. One of the crucial requirements for utilities is to ensure that the system reliability is maintained with the inclusion of microgrid topology. Therefore, this paper evaluates the reliability of a microgrid containing prioritized loads and distributed RES through a hybrid analytical-simulation method. The stochasticity of RES introduces complexity to the reliability evaluation. The method takes into account the variability of RES through Monte- Carlo state sampling simulation. The results indicate the reliability enhancement of the overall system in the presence of the microgrid topology. In particular, the highest priority load has the largest improvement in the reliability indices. Furthermore, sensitivity analysis is performed to understand the effects of the failure of microgrid islanding in the case of a fault in the upstream network

    The prevalence of domestic violence among pregnant women in Nigeria: a systematic review.

    Get PDF
    To identify, appraise, and synthesize research evidence on the prevalence of domestic violence (DV) among pregnant women in Nigeria. We conducted a systematic review of all published studies between April 2004 and June 2016. Comprehensive searches were conducted on electronic databases such as PubMed, CINAHL, Global Health, MEDLINE, PsycINFO, Directory of Open Access Journals, Google Scholar, and electronic libraries of the authors' institution. Identified articles were screened in two stages against the inclusion criteria with titles and abstract screened first followed by full-text screening. Selected articles were assessed using the "guidelines for evaluating prevalence studies," and findings were synthesized narratively. Among 19 studies that met the inclusion criteria, two articles were excluded due to low methodological quality and 17 articles were included in the review. The prevalence of DV during pregnancy in Nigeria ranged between 2.3% and 44.6% with lifetime prevalence rates ranging between 33.1% and 63.2%. Physical, sexual, psychological, and verbal abuses were the most frequent types of DV reported in this review. The most common perpetrators were husbands, as reported in 11 of the 17 studies. Pregnant women between the ages of 20 and 30 years were the most common victims of DV. Our review suggests high prevalence of DV in pregnancy among women in Nigeria and higher lifetime prevalence. However, determining an overall, synthesized accurate prevalence rate of DV within this population based on existing evidence presents a challenge. The findings have important implications for stakeholders such as planners, policy makers, maternity care providers, and researchers in public health and social policy at national, regional, and international levels toward combating the issue. OBJECTIVE METHOD RESULTS CONCLUSIO

    About the connection between the CC_{\ell} power spectrum of the Cosmic Microwave Background and the Γm\Gamma_{m} Fourier spectrum of rings on the sky

    Full text link
    In this article we present and study a scaling law of the mΓmm\Gamma_m CMB Fourier spectrum on rings which allows us (i) to combine spectra corresponding to different colatitude angles (e.g. several detectors at the focal plane of a telescope), and (ii) to recover the ClC_l power spectrum once the Γm\Gamma_m coefficients have been measured. This recovery is performed numerically below the 1% level for colatitudes Θ>80\Theta> 80^\circ degrees. In addition, taking advantage of the smoothness of the ClC_l and of the Γm\Gamma_m, we provide analytical expressions which allow to recover one of the spectrum at the 1% level, the other one being known.Comment: 8 pages, 8 figure

    The effect of priming on germination characteristics of barley seeds under drought stress conditions

    Get PDF
    Seed priming methods have been used to increase germination and seedling establishment under different abiotic stress conditions. Seed priming was used in barley to increase seed germination and tolerance on stress exposure. Barley seeds were treated with various priming agents for different time and temperatures. The effect of priming was assessed on germination characteristics on subsequent exposure to drought (PEG-12 bar) stress for 7 days. Seed priming treatments significantly (p≤ 0.01) affected germination percentage (GP), normality seedling percentage (NSP), germination Index (GI), germination uniformity (GU), means time to germination (MTG), coefficient of velocity of germination (CVG), seedling vigor index (SVI) and coefficient of allometry (AC). Seed priming with gibberelic acid (GA), salicylic acid (SA), ascorbic acid (ASc), hydropriming (HP), osmopriming (OP) and combined treatments (CT) significantly (p≤ 0.01) increased germination characteristics, compared to the unprimed. Seed priming with concentrations 25, 50 ppm of GA for 15 h at 10°C, 25 ppm of SA for 12 h at 10°C, 50 ppm of ASc for 12 h at 15°C, treatment 16 h hydropriming at 10°C and -15 bar PEG for 24 h for osmopriming maybe considered as optimal treatment for priming of barley seeds in drought stress conditions. In some cases, combined treatments are better than the separate treatments. Seed priming with PEG (potential -l5 bar PEG for 24 h at 10°C) was more effective in drought stress than the other treatments

    Estimation method for determining surface film conductance during cooling of fish packages.

    Get PDF
    This paper presents an alternative method for determining the surface film conductance of an infinite fish slab subjected to the cooling process. Many methods have been published, but their solutions have inherent appreciable inaccuracy and limitations. The present authors used the temperature histories of five locations within a slab sample of fish, obtained by the experimental investigation part of this work, along with the inverse heat conduction problem (IHCP) technique to develop a correlation for variable surface film conductance. When the above correlation was used for temperature predictions, the predicted and experimentally measured temperature distribution profiles were compared numerically. Better agreement than that implemented by other investigators was achieved. This revealed the accuracy and superiority of the present method, and the limitations of other methods are overcome in this method

    Assessment of PULP score in predicting 30-day perforated duodenal ulcer morbidity, and comparison of its performance with Boey and ASA, a retrospective study

    Get PDF
    Background: /aim: Scores commonly employed to risk stratify perforated peptic ulcer patients include ASA (American Society of Anesthesiologists), Boey and peptic ulcer perforation score (PULP). However, few studies assessed and compared the accuracy indices of these three scores in predicting post PPU repair 30-day morbidity. We assessed accuracy indices of PULP, and compared them to Boey and ASA in predicting post perforated duodenal (PDU) ulcer repair 30-day morbidity. Methods: Retrospective chart review of all PDU patients (perforated duodenal ulcers only) at the largest two hospitals in Qatar (N = 152). Data included demographic, clinical, laboratory, operative, and post repair 30-day morbidity. Area under the Curve (AUC), sensitivity and specificity were computed for each of the 3 scores. Multivariate logistic regression assessed the accuracy indices of each score. Results: All patients were males (M age 37.41 years). Post PDU repair 30-day morbidity was 10.5% (16 morbidities). Older age, higher ASA (?3), Boey (?1) or PULP (?8) scores, shock on admission and preoperative comorbidities; and conversely, lower hemoglobin and albumin were all positively significantly associated with higher post PDU 30-day morbidity. PULP displayed the largest AUC (72%), and was the only score to significantly predict 30-day morbidity. The current study is the first to report the sensitivity and specificity of these three scores for post PDU repair 30-day morbidity; and first to assess accuracy indices for PULP in predicting post PDU repair 30-day morbidity. Conclusion: PULP score had the largest AUC and was the only score to significantly predict post PDU repair 30-day morbidity.Scopu

    Relationship between platelet parameters and sudden sensorineural hearing loss: a systematic review and meta-analysis

    Get PDF
    Background: Sudden deafness or sudden sensorineural hearing loss (SSNHO is defined as sensorineural hearing loss of greater than 30 dB over 3 contiguous puretone frequencies occurring within 3 days' periodObjective: To investigate the relationship of some platelet parameters including platelet count (PC), mean platelet volume (MPV) and platelet distribution width (PDW) with the occurrence of SSNHL.Data source: A PubMed, Science Direct, Scopus, OVID, EMBASE and Google Scholar search (date last searchedApril2016) search was done. No restrictions of time, language and location were placed.Study selection: All case-control studies which have been studied the relationship of PC, MPV and PDW with the occurrence of SSNHL were included in the meta-analysis.Data extraction: The required data from selected studies including the title, authors, publication date, location of study, sample size of patients and control groups, number of withdrawals, the mean and standard deviation of PC, MPV and PDW for patients and control groups and the result of different tests were extracted and entered to EX CELL.Data synthesis: A total of 9 case-control studies were r found in our search from them 8 studies have reported mean PC, 7 studies have reported mean MPV and 4 studies have reported mean PDW. Our analysis showed that mean PC of patients is 0.03 (-0.14-0.20) unit higher than that of controls with 95% CI which is not statistically significant. Also, mean MPV of patients is 0.31 (-0.03-0.65) unit higher than that of controls with 95% CI which is statistically not significant too. Finally, mean PDW of patients is 0.70 (0.03- 1.37) unit higher than that of controls with 95% CI which is statistically significant.Conclusions: Our study confirmed only the probable relationship of PDW and SSNHL but due to the limited studies on this subject more studies is needed

    The solute carrier SLC7A8 is a marker of favourable prognosis in ER-positive low proliferative invasive breast cancer

    Get PDF
    Purpose: Breast cancer (BC) is a heterogeneous disease consisting of various subtypes, withdifferent prognostic and therapeutic outcomes. The amino acid transporter, SLC7A8, is over expressed in estrogen receptor positive BC. However the consequences of this overexpression, it terms of disease prognosis, is still obscure. This study aimed to evaluate the biological and prognostic value of SLC7A8 in BC with emphasis on the intrinsic molecular subtypes.Methods: SLC7A8 was assessed at the genomic, using METABRIC data (n=1,980), and proteomic, using immunohistochemistry and TMA (n=1,562), levels in well-characterised primary BC cohorts. SLC7A8 expression was examined with clinicopathological parameters, molecular subtypes, and patient outcome.Results: SLC7A8 mRNA and SLC7A8 protein expression were strongly associated with good prognostic features, including small tumour size, low tumour grade and good Nottingham Prognostic Index (NPI) (all
    corecore