A 20-year satellite-reanalysis-based climatology of extreme precipitation characteristics over the Sinai Peninsula

Extreme precipitation events and associated flash floods caused by synoptic cyclonic systems profoundly impact society and the environment, particularly in arid regions. This study brings forward a satellitereanalysis-based approach to quantify extreme precipitation characteristics over the Sinai Peninsula (SiP) in Egypt from a statistical–synoptic perspective for the period of 2001–2020. With a multi-statistical approach developed in this research, SiP’s wet and dry periods are determined. Using satellite observations of precipitation and a set of derived precipitation indices, we characterize the spatiotemporal variations of extreme rainfall climatologies across the SiP. Then, using the reanalysis datasets, synoptic systems responsible for the occurrence of extreme precipitation events along with the major tracks of cyclones during the wet and dry periods are described. Our results indicate that trends and spatial patterns of the rainfall events across the region are inconsistent in time and space. The highest precipitation percentiles ( ∼ 20 mm per month), frequencies (∼ 15 d per month with rainfall ≥ 10 mm d−1), standard deviations (∼ 9 mm month per month), and monthly ratios (∼ 18 %) are estimated in the northern and northeastern parts of the region during the wet period, especially in early winter; also, a substantial below-average precipitation condition (drier trend) is clearly observed in most parts except for the south. Mediterranean cyclones accompanied by the Red Sea and Persian troughs are responsible for the majority of extreme rainfall events year-round. A remarkable spatial relationship is found between SiP’s rainfall and the atmospheric variables of sea level pressure, wind direction, and vertical velocity. A cyclone-tracking analysis indicates that 125 cyclones (with rainfall ≥ 10 mm d−1) formed within, or transferred to, the Mediterranean basin and precipitated over the SiP during wet periods compared to 31 such cyclones during dry periods. It is estimated around 15 % of cyclones with sufficient rainfall > 40 mm d−1 would be capable of leading to flash floods during the wet period. This study, therefore, sheds new light on the extreme precipitation characteristics over the SiP and its association with dominant synoptic-scale mechanisms over the eastern Mediterranean region

Investigation of the prevalence of latent tuberculosis in cancer patients compared to non-cancer patients: a case-control study

BackgroundLatent tuberculosis (TB) can reactivate in immunocompromised individuals, such as cancer patients undergoing chemotherapy, leading to severe complications. Understanding the prevalence of latent TB in this high-risk group is crucial, especially in regions with moderate to high TB burdens.AimThis study aims to determine the prevalence of latent tuberculosis in cancer patients before chemotherapy and immunotherapy to guide preventive interventions and reduce the risk of TB reactivation.MethodsThis case-control study was conducted at Sina Hospital in Tehran, Iran, from 2012 to 2022. A total of 392, including 107 newly diagnosed cancer (case) and 285 non-cancer (control) patients, were enrolled in this study. All patients had received the Bacillus Calmette-Guérin (BCG) vaccine at the age of one. They underwent a thorough clinical examination and were screened using the tuberculin skin test (TST) to detect latent TB. Any active TB cases were identified through acid-fast smear tests. The data collected from the study participants was then analyzed.ResultsThe results showed no significant difference in the size of TST between cancer and non-cancer patients (cases: median = 2 mm, IQR: 1–12; controls: median = 2 mm, IQR: 1–5; p = 0.09). The prevalence of latent TB was 27.1% in cancer patients and 20.7% in non-cancer patients, with no significant association identified between latent TB and malignancies (P-value = 0.176). Over a median follow-up of 4 years, mortality was significantly higher in cancer patients compared to controls (42.1% vs 1.8%; P< 0.001, OR = 40.64). Additionally, deceased patients exhibited a greater prevalence of latent TB (44% vs 19.3% in survivors; P< 0.001, OR = 3.28), and increased size of TST was associated with higher mortality risk among cancer patients.ConclusionIn conclusion, this study emphasizes the need for vigilant latent TB screening in cancer patients, given the association between larger TST sizes and increased mortality risk. While no direct link between cancer type and latent TB was found, proactive TB management remains crucial, particularly for those undergoing immunosuppressive therapy

A 20-year satellite-reanalysis-based climatology of extreme precipitation characteristics over the Sinai Peninsula

Extreme precipitation events and associated flash floods caued by the synoptic cyclonic-systems have profound impacts on society and the environment particularly in dry regions. This study brings forward a satellite-reanalysis-based approach to quantify the extreme precipitation characteristics over the Sinai Desert in Egypt, from a statistical-synoptic perspective for the period of 2001–2020. Using the satellite remote-sensing precipitation and a set of climate indices, we characterize the spatiotemporal distribution of extreme rainfall climatologies across the Sinai region. Then, using the reanalysis dataset, the synoptic systems responsible for the occurrence of precipitation events along with the major tracks of cyclones during the wet and dry periods are explored. Our results indicate that the temporal changes and spatial patterns of the precipitation events do not show a homogenous tendency, rather lack of spatiotemporal coherence across the Sinai. Northern parts of the Sinai, unlike other areas, exhibit the highest anomalies (approx. ±45 mm/decade); and the annual rainfall trends indicate a drier-climate in the north at −0.03 mm/decade, while a wetter-climate is observed in the central and southern parts at 0.10 and 0.36 mm/decade, respectively. The Mediterranean cyclones accompanied by the Red Sea -and Persian Troughs are responsible for the majority of extreme rainfall events all-round the year. A remarkable spatial relationship between the Sinai’s rainfall and the atmospheric variables of sea level pressure, wind direction and vertical velocity is found. Furthermore, the cyclone-tracking analysis indicates that 125 and 31 cyclones (rainfall ≥ 10mm/day) either formed within -or transferred to the Mediterranean basin and precipitated over the Sinai during wet and dry periods, respectively; while some (~15 % with rainfall > 40mm/day) being capable of leading to flash flood in the wet period of the region. This study, therefore, sheds new light on the extreme rainfall characteristics and the dominant synoptic mechanisms over the Sinai region in the eastern Mediterranean basin

Efficacy of Direct Acting Antivirals (DAA) therapy in patients with recurrent hepatitis C after liver and kidney transplantation: a cross-sectional study

Background and objectivesDirect-acting antiviral (DAA) agents are now widely used to treat patients with hepatitis C infection (HCV) and effectively increase their sustained virologic response (SVR). However, the literature seems to lack or deficient evidence of DAA efficacy in more complicated patients, especially those with HCV reinfection after liver transplantation (LT) or liver-kidney (hepatorenal) transplantation (LKT). This study aimed to retrospectively evaluate the effectiveness of two different DAA regimens in LT and LKT patients with HCV reinfection.MethodsThis cross-sectional study was conducted at three hospitals in Tehran, Iran, from 2014 to 2020, enrolling 53 patients with recurrent HCV infection after LT (n = 35) or LKT (n = 18). Patients were treated for 12 weeks with one of two DAA regimens: 37 patients (70%) received Daclatasvir and Sofosbuvir (SOF + DCV), while 16 patients (30%) received Sofosbuvir and Ledipasvir (SOF + LDV). Ribavirin (RBV) was added as an adjunct antiviral in 28 patients (52.8%). To assess the SVR, all patients were followed for 12 weeks after treatment.ResultsBoth DAA regimens were well-tolerated and effective, with 94.6% (35 of 37) achieving SVR-12 in the SOF + DCV group and 93.8% (15 of 16) in the SOF + LDV group. Additionally, SVR-12 rates were promising across treatment durations, with 93.9% (31 of 33) in the 12-week group and 95% (19 of 20) in the 24-week group achieving undetectable HCV RNA. No significant difference in SVR was observed between the two regimens (p = 0.439).ConclusionThe DAA-based therapeutic regimen was well tolerated and showed significant effectiveness in achieving the virologic response in patients with HCV reinfection after LT or LKT

Evaluation of overall survival and disease-free survival of adjuvant chemotherapy and hormone therapy in patients with breast cancer

Abstract : Background: This study evaluated the effect of adjuvant chemotherapy and hormone therapy on overall survival and disease-free survival in patients with breast cancer with hormone receptor-positive, HER2-negative tumor without lymph node involvement. Methods: Breast cancer patients with hormone receptor-positive, HER2-negative, and no lymph node involvement were included in this retrospective cohort study. Patient records were used to collect data on sex, age, time of disease onset, tumor subtype, tumor size, grade, lymphovascular and perineural involvement, ki67, and treatment protocols. Patients were divided into 2 groups: Patients who received both adjuvant chemotherapy and hormonal therapy and patients who received hormonal therapy only. Disease-free survival index (DFS) and overall survival index (OS) were evaluated. Results: Sixty-seven female patients were enrolled in this study. Of them, 68.2% received both adjuvant chemotherapy and hormonal therapy and 31.6% received hormonal therapy only. During follow-up, recurrences occurred in 8 patients. The 3-year and 5-year DFS were 93.4% and 90%, respectively. The 3-year and 5-year DFS were 94% and 92%, respectively, in patients who received both adjuvant chemotherapy and hormonal therapy, and 91% and 85%, respectively, in patients who received hormonal therapy. None of the factors studied affected the 3-year and 5-year DFS. The 3-year and 5-year DFS OS were 98.6% and 96.9%, respectively CONCLUSION: Adjuvant chemotherapy in patients with breast cancer with hormone receptor-positive, HER2-negative, and no lymph node involvement compared with similar patients receiving hormone therapy alone had no significant difference in disease-free survival index and overall survival index. Keywords: breast cancer; disease-free survival index; overall survival inde

Ecological Footprint Prediction based on Global Macro Indicators in G-20 Countries using Machine Learning Approaches

Abstract Paying attention to human activities in terms of land grazing infrastructure, crops, forest products and carbon impact, the so-called ecological impact (EF) is one of the most important economic issues in the world. In the present study, data from global databases were used. The ability of the penalized regression approach (PR including Ridge, Lasso and Elastic Net) and artificial neural network (ANN) to predict EF indices in the G-20 over the past two decades (1999–2018) was depicted and compared. For this purpose, 10-fold cross-validation was used to assess predictive performance and to specify a penalty parameter for PR models. Based on the results, a slight improvement in prediction performance was observed over linear regression. Using the Elastic Net model, more global macro indices were selected than Lasso. Although Lasso included only some indicators, it still had better predictive performance among PR models. Although the findings using PR methods were only slightly better than linear regression, their interest in selecting a subset of controllable indicators by shrinking the coefficients and creating a parsimonious model was apparent. As a result, penalized regression methods would be preferred, using feature selectivity and interpretive considerations rather than predictive performance alone. On the other hand, neural network-based models with higher values of coefficients of determination (R2) and values lower of RMSE than PR and OLS had significant performance and showed that they are more accurate in predicting EF. The results showed that the ANN network could provide considerable and appropriate predictions for EF indicators in the G-20 countries. predictions</jats:p

On the Existence of Summer Shamal Wind Induced by the Zagros Mountains in the Middle East

Abstract A new structure is proposed to explain the mechanism governing the summer Shamal wind (SSW) formation in the Middle East (ME). Here, the irreplaceable role of the Zagros Mountains (ZAG) as the primary driver of a localized atmospheric circulation over the ME has been clarified. We show that the SSW is mainly established and maintained due to the local forcing of the ZAG. A background low‐level easterly flow dominates on the east side of the ZAG which is basically from Turkmenistan Anticyclone. The flow in association with a vertical heat advection over the ZAG while generating Iran anticyclone (IA) in the middle troposphere, develops so‐called regional atmospheric circulation over the ME. As a part of the localized circulation, descending air from IA establishes the Arabian anticyclone‐Zagros Trough coupling pattern over Mesopotamia. This coupling pattern is the significant driver of SSW and its induced dust storms over the ME

A Credit Approach to Measure Inherent Hazards Using the Fire, Explosion and Toxicity Index in the Chemical Process Industry: Case Study of an Iso-max Unit in an Iran Oil Refinery

Objectives: Indices are extensively used for ranking various units of a chemical process industry on the basis of the hazards they pose of risk a fire, explosion and toxicity release. Methods: This type of ranking enables the professionals to identify the more hazardous units from the less hazardous ones so that greater attention can be paid to the former. The key process subunits in the Iso-max unit were identified based on parameters such as process pressure, temperature and material value. In next step, the main parameters affecting the FETI were identified and estimated, and the Mond FETI index was calculated for each subunit. In addition, the criteria offset measures for each case were identified and their influences were studied. Results: The results showed that the process route’s potential hazardous characteristics, such as major incidents, were associated with one or more of the following dangerous phenomena: thermal radiation, blast (pressure wave) and ejection of fragments, release of toxic materials and chemical concentration in the air. Intake amount assessments and the corresponding risk of exposure were also produced. By using statistical incident data of the risks of fire, explosion and toxicity, exposure risks can be estimated more realistically as probabilities. This approach is capable of comparing alternative processes to select the one which is inherently safest. Conclusion: Using this method, the exposure risks in a process can be identified sooner, and proper risk management decisions can be made early in the process development or predesign stages