SARS-CoV-2 Epidemic in the Israeli Defense Force-Lessons Learned From Our rt-PCR Screening Policy.

BACKGROUND: During the SARS-CoV-2 pandemic, multiple preventative measures were used to prevent the virus from spreading in the population. The Israeli defense force deployed further means to contain the disease, including putting units in quarantine, physical distancing and using masks, gowns and disinfectants when in contact with suspected patients. METHODS: We used reverse transcriptase-polymerase chain reaction (rt-PCR) tests to screen for patients among asymptomatic soldiers within units participating in civilian aid or in close contact with known patients, using personal protective equipment. Positive results were repeated and followed with serological testing to verify the nature of results. RESULTS: Between April and May 2020, we screened a total of 1,453 soldiers in 13 different units. We found 11 false positive results, leading to unnecessary measures until resolution, and three true positive results (0.2%). All true positive results had unreported symptoms concomitant with SARS-CoV-2 disease. These results led to the resolution of this screening policy. CONCLUSION: Screening asymptomatic army personnel in this setting with rt-PCR test for SARS-CoV-2 is not warranted and leads to unnecessary false positive results. Efforts should be directed at identifying symptomatic patients.

Trends in prehospital pain management: two decades of point-of-injury care.

BACKGROUND: Pain control in trauma is an integral part of treatment in combat casualty care. More soldiers injured on the battlefield need analgesics for pain than life-saving interventions (LSIs). Early treatment of pain improves outcomes after injury, while inadequate treatment leads to higher rates of post-traumatic stress disorder (PTSD). OBJECTIVES: To describe the experience of the Israel Defense Forces (IDF) Medical Corps with prehospital use of analgesia. METHODS: All cases documented in the IDF-Trauma Registry between January 1997 and December 2019 were examined. Data collection included analgesia administered, mechanism of injury, wound distribution, and life-saving interventions performed. RESULTS: Of 16,117 patients, 1807 (11.2%) had at least one documented analgesia. Demographics included 91.2% male; median age 21 years. Leading mechanism of injury was penetrating (52.9%). Of injured body regions reported, 46.2% were lower extremity wounds. Most common types of analgesics were morphine (57.2%) and fentanyl (27%). Over the two decades of the study period, types of analgesics given by providers at point of injury (POI) had changed. Fentanyl was introduced in 2013, and by 2019 was given to 39% of patients. Another change was an increase of casualties receiving analgesia from 5-10% until 2010 to 34% by 2019. A total of 824 LSIs were performed on 556 patients (30.8%) receiving analgesia and no adverse events were found in any of the casualties. CONCLUSIONS: Most casualties at POI did not receive any analgesics. The most common analgesics administered were opioids. Over time analgesic administration has gained acceptance and become more commonplace on the battlefield.

Personality disorders and cause-specific mortality: a nationwide study of 2 million adolescents.

BACKGROUND: Personality disorders are prevalent in 6-10% of the population, but their risk for cause-specific mortality is unclear. The aim of the study was to assess the association between personality disorders diagnosed in late adolescence and all-cause as well as cause-specific (cardiovascular-related, external-related) mortality. METHODS: We performed a longitudinal study on a historical prospective cohort based on nationwide screening prior to recruitment to the Israeli army. The study participants were 16-19-year-old persons who attended the army screening (medical and cognitive, including screening for psychiatric disorders) between 1967 and 2006. Participants were followed from 1967 till 2011. RESULTS: The study included 2 051 606 subjects, of whom 1 229 252 (59.9%) were men and 822 354 (40.1%) were women, mean age 17.36 years. There were 55 508 (4.5%) men and 8237 (1.0%) women diagnosed with personality disorders. The adjusted hazard ratio (HRs) for coronary, stroke, cardiovascular, external-related causes and all-cause mortality among men with personality disorders were 1.34 (1.03-1.74), 1.82 (1.20-2.76), 1.45 (1.23-1.71), 1.41 (1.30-1.53) and 1.44 (1.36-1.51), respectively. The absolute rate difference for all-cause mortality was 56.07 and 13.19 per 105 person-years among men and women, respectively. Among women with personality disorders, the adjusted HRs for external-related causes and all-cause mortality were 2.74 (1.87-4.00) and 2.01 (1.56-2.58). Associations were already evident within 10 years of follow-up. CONCLUSIONS: Personality disorder in late adolescence is associated with increased risk of cardiovascular, external- and all-cause mortality. Increased cardiovascular mortality is evident before the age of 40 years and may point to the importance of lifestyle education already in youth.

Short Communication: Combining Ethics With Efficiency-Israel Defense Forces' Experience in Clinical Trials During the Coronavirus Disease 2019 Pandemic.

The coronavirus disease 2019 (COVID-19) pandemic, first reported in China, soon spread worldwide, has evolved into one of the most complex global public health crises the world has encountered in the last several decades. Conducting military medical research is vital to study the unique influences of military service conditions on soldiers' health and to improve the medical response in various emergency periods. The Israel Defense Forces (IDF) Medical Corps maintains an Institutional Review Board (IRB) which reviews clinical studies conducted within the IDF. During the COVID-19 pandemic, the IRB of the IDF had to rapidly implement procedural modifications in order to comply with expanding urgent demands for research without compromising ethical standards. The ethical dilemmas and the IDF policy and perspective are outlined in this article.

Comparison of the Effects of Motion and Environment Conditions on Accuracy of Handheld and Finger-Based Pulse Oximeters.

INTRODUCTION: The most common cause of preventable death on the battlefield is significant blood loss, eventually causing decrease in tissue oxygen delivery. Pulse oximeters (POs) are widely used by the Israeli Defense Forces to obtain fast and noninvasive information about peripheral oxygen saturation (SpO2). However, POs are produced by different manufacturers and therefore include different sensors and are based on distinctive algorithms. This makes them susceptible to different errors caused by factors varying from environmental conditions to the severity of injury. The objectives of this study were to compare the reliability of different devices and their accuracy under various conditions. MATERIAL AND METHODS: Six POs underwent performance analysis. The finger-based category included: MightySat by Masimo, Onyx II by Nonin, and CMS50D by Contec. The handheld category comprised: RAD5 by Masimo, 9847 model by Nonin, and 3301 model by BCI. Several environmental and physiological parameters were altered using the ProSim8 simulator by Fluke biomedical, forming unique test cases under which the devices were tested in stationary and motion conditions. RESULTS: All finger-based POs showed higher error rates of PO SpO2 and heart rate measurements in motion conditions, regardless of the manufacturer. However, newer devices in the handheld category were not affected. Results presented in Phase II showed that the SpO2 measurement error in all the devices was affected by pigmentation. However, the CMS50D, considered a low-cost device, had a significantly higher error size than other devices. In the devices that were influenced both by pigmentation and the finger cleanliness factors, the combined detected error size was clinically significant. The pigmentation, ambient light, and finger cleanliness also had a significant effect on the heart rate measurement in the CMS50D model, unlike the handheld devices, which were not affected. During Phase II, neither the Nonin nor the Masimo devices were deemed to have a significant advantage. CONCLUSION: Considering measurement limitations of POs used is extremely important. Use of handheld devices should be favored for use in motion conditions. Technologically advanced and/or recently developed devices should be preferred because of evolving algorithms, which decrease or eliminate the error factors. The "dirty finger" effect on the measurement error cannot be neglected and therefore the action of finger cleaning should be considered part of the treatment protocol.

Medical Challenges in Underground Warfare.

INTRODUCTION: Throughout history, underground systems have served military purposes in both offensive and defensive tactical settings. With the advance of underground mining, combat tactics, and weapon systems, providing medical support in the subterranean battlefield is a constantly growing challenge. This retrospective cohort study describes the Israeli Defense Force (IDF) Medical Corps experience with treating casualties from underground warfare, as recorded in the IDF Trauma Registry. METHODS: A retrospective cohort study of all casualties engaged in underground warfare, between the years 2004-2018. Medical data were extracted from the IDF Trauma Registry and tactical data were obtained from operational reports. An expert committee characterized the most prevalent challenges. Recommendations were based on a literature review and the lessons learned by the IDF experience. RESULTS: During the study period, 26 casualties were injured in the underground terrain. Of casualties, 12 (46%) due to blast injuries, 9 (35%) were due to smoke inhalation, and 5 (19%) due to crushing injuries. All were males, and the average age was 21.6 years. Ten (38%) were killed in action (died before reaching a medical facility). All 16 casualties reaching the hospital survived (Table I). The expert committee divided the most common challenges into three categories-tactical, environmental, and medical. An overview of medical response planning, common injuries, and designated combat casualty care are discussed below. As in all combat casualty care, the focus should be on safety, bleeding control, and rapid evacuation. CONCLUSION: To plan and provide medical support, a thorough understanding of operational planning is essential. This manuscript presents the evolution of underground warfare, tactical and medical implications, environmental hazards, and common casualty care challenges.

Medial tibial stress fracture diagnosis and treatment guidelines.

OBJECTIVES: To validate and make evidence based changes to the Israel Defense Forces medial tibial stress fracture diagnosis and treatment protocol. DESIGN: Prospective cohort study. METHODS: 429 Elite infantry recruits were reviewed for signs and symptoms of medial tibial stress fracture during 14 weeks of basic training. Suspicion of medial tibial stress fracture was based on the presence of pain, tenderness <1/3 the length of the tibia and a positive fulcrum and/or hop test. Recruits with suspected medial tibial stress fractures were initially treated with 10-14 days of rest. Bone scan was performed only when recruits failed to respond to the rest regimen or required immediate diagnosis. RESULTS: 31 Out of 49 recruits with a suspicion of medial tibial stress fracture underwent bone scan, including 8/26 recruits whose symptoms did not resolve after being treated clinically as stress fractures. There was a significantly greater incidence of medial tibial stress fractures when a positive hop test was present in addition to tibial pain and tenderness (p=0.0001), odds ratio 52.04 (95% CL, 2.80-967.74). Medial tibial stress fracture was found to occur when the band of tibial tenderness was ≤10cm in length. Tibial pain scores were not predictive of stress fracture. CONCLUSIONS: This validation study provides the clinician with evidence based guidelines for the clinical diagnosis and treatment of medial stress fractures and their differentiation from shin splints. An initial treatment protocol without the use of imaging was found to be effective in more than two-thirds of the cases.

The Dental, Oral, Medical Epidemiological (DOME) Study: Protocol and Study Methods.

OBJECTIVES: To develop and present the methods utilized for the Dental, Oral, Medical Epidemiological (DOME) study. METHODS: The DOME is an electronic record-based cross-sectional study, that was conducted to measure the dental, periodontal, and oral morbidities and their associations with systemic morbidities, among a nationally representative sample of young to middle-aged adults military personnel from the IDF (Israel Defense Forces). To that end, we developed a strict protocol including standardized terminology, data collection, and handling. RESULTS: Data for the DOME study was derived simultaneously from three electronic records of the IDF: (1) a central demographic database, (2) the dental patient record (DPR), and (3) the medical computerized patient record (CPR). The established DOME repository includes socio-demographic, dental and medical records of 132,354 young to middle-age military personnel from the IDF, who attended the dental clinics during the year 2015. Records of general military personnel (N > 50,000), with no recorded dental visits during the study period, served as a control group regarding all other parameters except dental. The DOME study continues and is currently collecting longitudinal data from the year 2010 until 2020. The IDF employs a standardized uniform administrative and clinical work-up and treatment protocols as well as uniform computerized codes. We describe the standardized definitions for all the parameters that were included: socio-demographics, health-related habits, medical and dental attendance patterns, and general and dental health status. Multicollinearity analysis results of the sociodemographic and medical study parameters are presented. CONCLUSION: Standardized work-up and definitions are essential to establish the centralized DOME data repository to study the extent of dental and systemic morbidities and their associations.

Clinical Course and Outcomes of Severe Covid-19: A National Scale Study.

Knowledge of the outcomes of critically ill patients is crucial for health and government officials who are planning how to address local outbreaks. The factors associated with outcomes of critically ill patients with coronavirus disease 2019 (Covid-19) who required treatment in an intensive care unit (ICU) are yet to be determined. METHODS: This was a retrospective registry-based case series of patients with laboratory-confirmed SARS-CoV-2 who were referred for ICU admission and treated in the ICUs of the 13 participating centers in Israel between 5 March and 27 April 2020. Demographic and clinical data including clinical management were collected and subjected to a multivariable analysis; primary outcome was mortality. RESULTS: This study included 156 patients (median age = 72 years (range = 22-97 years)); 69% (108 of 156) were male. Eighty-nine percent (139 of 156) of patients had at least one comorbidity. One hundred three patients (66%) required invasive mechanical ventilation. As of 8 May 2020, the median length of stay in the ICU was 10 days (range = 0-37 days). The overall mortality rate was 56%; a multivariable regression model revealed that increasing age (OR = 1.08 for each year of age, 95%CI = 1.03-1.13), the presence of sepsis (OR = 1.08 for each year of age, 95%CI = 1.03-1.13), and a shorter ICU stay(OR = 0.90 for each day, 95% CI = 0.84-0.96) were independent prognostic factors. CONCLUSIONS: In our case series, we found lower mortality rates than those in exhausted health systems. The results of our multivariable model suggest that further evaluation is needed of antiviral and antibacterial agents in the treatment of sepsis and secondary infection.

SOS Teeth: Age and Sex Differences in the Prevalence of First Priority Teeth among a National Representative Sample of Young and Middle-Aged Adults.

BACKGROUND: "SOS teeth" are defined as the first priority teeth for treatment, that have distinct cavitation reaching the pulp chamber or only root fragments are present. OBJECTIVES: To assess the prevalence and distribution of SOS teeth with regard to age and sex difference among young to middle-aged adults. METHODS: This is a cross-sectional records-based study of a nationally representative sample, consisting of young to middle-aged military personnel, who attended the military dental clinics of the Israel Defense Forces (IDF) for one year. SOS teeth definition corresponds to code number 6 of the "Caries Assessment Spectrum and Treatment (CAST)" as an instrument to assess dental caries. Data pertaining to age and sex were drawn from the central demographic database and that of SOS teeth were obtained from the Dental Patient Record (DPR). RESULTS: The study included 132,529 dental records. The prevalence of patients with SOS teeth was 9.18 % (12,146/132,323). The number of teeth that were found to be SOS teeth was 18,300, i.e., 1.5 SOS teeth per "diseased" patient (18,300/12,146). The mean number of SOS teeth per the whole study population was 0.14 ± 0.52 and the range was 0-20. The mean number of SOS teeth per patient had a statistically significant negative correlation with age (p < 0.001; Odds Ratio (OR) = 0.997; 95% confidence interval: 0.997-0.998) and with male sex compared to females (p < 0.001; OR = 1.029 confidence interval: 1.023-1.036). CONCLUSION: Assessment of first priority SOS teeth may be part of the dentist's work-up. It provides dentists and health authorities with useful information regarding urgent dental care needs to plan dental services.

Cognitive and physical performance are well preserved following standard blood donation: A noninferiority, randomized clinical trial.

BACKGROUND: A walking blood bank (WBB) refers to the use of fellow combatants for battlefield blood donation. This requires pretesting combatants for infectious diseases and blood type. A fundamental prerequisite for this technique is that the donating soldier will suffer minimal physiological and mental impact. The purpose of the current study is to assess the effect of blood shedding on battlefield performance. METHODS: This is a double-blind randomized control trial. Forty Israel Defense Forces combatants volunteered for the study. Participants underwent baseline evaluation, including repeated measurement of vital signs, cognitive evaluation, physical evaluation, and a strenuous shooting test. Three weeks after the baseline evaluation, subjects were randomized to either blood donation or the control group. For blinding purposes, all subjects underwent venous catheterization for the duration of a blood donation. Repeated vital signs and function evaluation were then performed. RESULTS: Thirty-six patients were available for randomization. Baseline measurements were similar for both groups. Mean strenuous shooting score was 80.5 ± 9.5 for the control group and 82 ± 6.6 for the test group (p = 0.58). No clinically or statistically significant differences were found in tests designed to evaluate cognitive performance or physical functions. Vital signs taken multiple times were also similar between the test and control groups. CONCLUSIONS: Executive, cognitive, and physical functions were well preserved after blood donation. This study supports the hypothesis that a WBB does not decrease donor combat performance. The categorical prohibition of physical exercise following blood donation might need to be reconsidered in both military and civilian populations.

Measures to Limit COVID-19 Outbreak Effects Among Military Personnel: Preliminary Data.

INTRODUCTION: The COVID-19 outbreak posed a threat to the readiness of military forces as well as their ability to fulfill missions. Seeing that military forces have been encountering similar challenges, we found it eminent to share the Israeli Defense Force (IDF) Northern Command's (NC) preliminary experience. MATERIALS AND METHODS: We retrospectively summarized the actions that were taken by our team, focusing on 18 battalions at the Israeli NC. These actions included promoting a series of organizational changes in terms of social distancing and medical regulations as well as working to strengthen medical leadership through designated video meetings with medical commanders across our organization. Meetings included relevant clinical education, updates, and leadership building. These actions and others were aimed to increase our influence on the decision-making processes. While we conducted real-time reverse transcriptase polymerase chain reaction SARS-CoV-2 laboratory tests for soldiers who were suspected to have COVID-19 (those presenting with compatible signs and symptoms after having been exposed to a confirmed COVID-19 patient), we were not able to screen healthy populations, nor did we have serum antibody serologic tests available during the study period. We reviewed the COVID-19 outbreak national data, obtained from Ministry of Health publishings and the IDF databases. Data were included from February 26th, 2020 (day 0, first COVID-19 patient in Israel) to April 19th, 2020 (day 53, about 1 month after most of the COVID-19 regulation were issued in the NC). RESULTS: The mean age of the battalion soldiers was 21.29 ± 4.06 (range 18-50), 81.34% male. Most restrictions were issued on day 18. On day 53, 98.85% of the personnel in the battalions were kept active and asymptomatic in their units. CONCLUSIONS: Despite the limited availability of laboratory testing for COVID-19 our actions enabled us to lead a strict risk-management policy while maintaining most of the available workforce.

Socioeconomic inequalities and severe obesity-Sex differences in a nationwide study of 1.12 million Israeli adolescents.

INTRODUCTION: In a nationwide population of adolescents, we investigated the sex-specific association of socioeconomic position (SEP) with severe obesity, and trends over time. METHODS: The cohort comprises all Israeli adolescents (mean ± SD age 17.3 ± 0.5 years) who were medically examined, before mandatory military service during 2000 to 2015. Of 1 120 362 adolescents, 239 816 (21.4%) were classified with overweight or with obesity classes I to III using the International Obesity Task Force criteria. Data were compared between 2000 to 2009 and 2010 to 2015. RESULTS: Considering more advantaged residential SEP as the reference group, the respective odds ratios (ORs ± 95%CI) of less advantaged SEP for obesity classes I to III in 2010 to 2015 were 1.48 (1.40-1.56), 1.66 (1.51-1.83), and 1.73 (1.45-2.08) for males; and 1.72 (1.60-1.84), 1.89 (1.66-2.15), and 2.62 (2.04-3.37) for females. All point estimates were higher than in the preceding decade. Considering female inductees from the more advantaged SEP as the reference group, ORs were higher for males in the more advantaged SEP group, for overweight, 1.31 (1.27-1.36); class I obesity, 1.29 (1.20-1.38); class II obesity, 1.34 (1.18-1.53); and class III obesity, 1.60 (1.24-2.07). Similarly, in the less and medium advantaged SEP groups, increased ORs for males compared with females were observed in all obesity groups. Results persisted using United States Centers for Disease Control and Prevention growth charts. CONCLUSIONS: Adolescents with less rather than more advantaged residential SEP are at greater risk of severe obesity. Adolescent males, of all residential SEP groups had higher odds than females for all classes of obesity.

The Israel Defense Forces Trauma Registry: 22 years of point-of-injury data.

BACKGROUND: Trauma is the leading cause of death among casualties between 1 and 44 years. A large proportion of trauma deaths occurs even before arriving at a medical facility. The paucity of prehospital data is a major reason for the lagging development of prehospital trauma care research. This study aims to describe the Israel Defense Forces Prehopistal Trauma Registry, the steps taken to improve data collection and quality, the resulting trends, and the registry's contribution to policymaking. METHODS: This study explores the quantity and quality of point of injury and prehospital data in the registry between the years 1997 and 2018. We assessed the number of recorded casualties per year, casualties characteristics, and documentation variables in the registry, with a specific focus on documentation of vital signs throughout the years. RESULTS: Overall, 17,905 casualties were recorded. Most casualties were young males (88.6%)-military personnel (52.7%), Syrian refugees (16.2%), Israeli civilians (11.5%), and Palestinians (9.0%). The median number of annual records from 2006 onward was significantly higher compared with before 2006 (1,000 [IQR, 792-1,470] vs. 142 [IQR, 129-156]). Between 2010 and 2018, documentation rate increased in all vital signs investigated including heart rate (56.3% vs. 1.0%), level of consciousness (55.1% vs. 0.3%), respiratory rate (51.8% vs. 0.3%), blood oxygen saturation (50.0% vs. 1.0%), Glasgow Coma Scale (48.2% vs. 0.4%), systolic blood pressure (45.7% vs. 0.8%), and pain (19.1% vs. 0.5%). CONCLUSION: Point of injury and prehospital documentation are rare yet essential for ongoing improvement of combat casualty care. The Israel Defense Forces Trauma Registry is one of the largest and oldest prehospital computerized military trauma registries in the world. This study shows a major improvement in the quantity and then in the quality of prehospital documentation throughout the years that affected guidelines and policy. Further work will focus on improving data completeness and accuracy. LEVEL OF EVIDENCE: Retrospective study, level III.

The spectrum of bacteria and mechanisms of resistance identified from the casualties treated in the Israeli field hospital after the earthquake in Nepal, 2015: A retrospective analysis.

BACKGROUND: On the April 25, 2015, a 7.8 magnitude earthquake struck Nepal. Soon-after, the Israel Defense Force (IDF) dispatched a tertiary field-hospital to Kathmandu. The field-hospital was equipped with a clinical laboratory with microbiology capabilities. Limited data exists regarding the spectrum of bacteria isolated from earthquake casualties. We aimed to identify the spectrum of bacteria and their mechanisms of resistance in-order to allow preparedness of antibiotic treatment protocols for future disaster scenarios. METHODS: - The field-laboratory phenotypically processed cultures from sterile and non-sterile sites as needed clinically. Later-on, the isolates were brought to Israel for quality control, definite identification and molecular characterization including mechanisms of resistance. RESULTS: A total of 82 clinical pathogens were isolated from 56 patients; 68% of them were Gram negative bacilli. The most common isolates were Enterobacteriaceae (55%) -36% carried bla-NDM and 33% produced Extended-spectrum beta-lactamase (ESBL), mostly blaCTX-M-15. Enterococcus spp were the main Gram positive bacteria isolated (22 isolates), yet, none were vancomycin resistant. The overall level of resistance was 27% MDR and 23% extensively drug resistant (XDR) bacteria. CONCLUSIONS: - Gram negative bacteria were the predominant organism cultured from the casualties, of them 77% were MDR or XDR. NDM was the most common resistance mechanism. The Antibiotic inventory of a field-hospital should be set to cover a wide and unexpected spectrum of bacteria, including resistant organisms. This report adds important information to the scarce reports of bacterial resistance in Nepal.

Prehospital definitive airway is not associated with improved survival in trauma patients.

BACKGROUND: The American College of Surgeons and the National Association of Emergency Medical Technicians advise securing a definitive airway if there is any doubt about the trauma patient's ability to maintain airway integrity. The objective of this study was to investigate the association between a success in securing a definitive airway in the prehospital setting and survival among trauma patients, in which the provider deemed a definitive airway was necessary. METHODS: The study included all trauma patients recorded in the Israel Defense Forces Trauma Registry between the years 2006 and 2018 for whom a prehospital attempt of securing a definitive airway was documented. The successful definitive airway group was defined by explicit documentation of success in either endotracheal intubation or cricothyrotomy. Logistic regression was performed to determine the association between success in securing a definitive airway and survival. RESULTS: A total of 566 (3.6%) trauma patients underwent attempts to secure a definitive airway (successful in 425 patients and unsuccessful in 141). Prehospital survival rates were similar (77.6% vs. 78.0%, p = 0.928) between the groups. Whether the definitive airway was successful did not affect the rates of prehospital survival, neither before (odds ratio, 0.98; 95% confidence interval, 0.61-1.54) nor after adjustment for the other factors (odds ratio, 0.91; 95% confidence interval, 0.55-1.46). CONCLUSION: This study was unable to find an association between a successful definitive airway in the prehospital setting and survival, even after adjustment for injury characteristics and in multiple models. Furthermore, survival rates were high among trauma patients in which the provider deemed a definitive airway as necessary yet failed in securing one. These results suggest that the liberal use of these invasive airway procedures in the prehospital setting should be reconsidered. LEVEL OF EVIDENCE: Retrospective study, lebel III.