High Occupancy Rates Research Articles

COVID-19 infection and attributable mortality in UK care homes: cohort study using active surveillance and electronic records (March-June 2020).

Backgroundepidemiological data on COVID-19 infection in care homes are scarce. We analysed data from a large provider of long-term care for older people to investigate infection and mortality during the first wave of the pandemic.Methodscohort study of 179 UK care homes with 9,339 residents and 11,604 staff. We used manager-reported daily tallies to estimate the incidence of suspected and confirmed infection and mortality in staff and residents. Individual-level electronic health records from 8,713 residents were used to model risk factors for confirmed infection, mortality and estimate attributable mortality.Results2,075/9,339 residents developed COVID-19 symptoms (22.2% [95% confidence interval: 21.4%; 23.1%]), while 951 residents (10.2% [9.6%; 10.8%]) and 585 staff (5.0% [4.7%; 5.5%]) had laboratory-confirmed infections. The incidence of confirmed infection was 152.6 [143.1; 162.6] and 62.3 [57.3; 67.5] per 100,000 person-days in residents and staff, respectively. Sixty-eight percent (121/179) of care homes had at least one COVID-19 infection or COVID-19-related death. Lower staffing ratios and higher occupancy rates were independent risk factors for infection.Out of 607 residents with confirmed infection, 217 died (case fatality rate: 35.7% [31.9%; 39.7%]). Mortality in residents with no direct evidence of infection was twofold higher in care homes with outbreaks versus those without (adjusted hazard ratio: 2.2 [1.8; 2.6]).Conclusionsfindings suggest many deaths occurred in people who were infected with COVID-19, but not tested. Higher occupancy and lower staffing levels were independently associated with risks of infection. Protecting staff and residents from infection requires regular testing for COVID-19 and fundamental changes to staffing and care home occupancy.

ASSESSMENT OF THE STATE OF DEVELOPMENT OF THE WORLD MARKET OF HOTEL SERVICES IN THE CONDITIONS OF COVID-19

The situation of development of the world market of hotel services in modern conditions is analyzed. High employment rates of the global hotel industry in 2014-2019 and a sharp decline in employment of the global hotel industry in the period 2019-2020 as a result of the coronavirus pandemic. An analysis of the capacity and occupancy of rooms in the leading countries of the world in 2014-2019. High growth rates of the number of hotel rooms in the United States, China, Mexico, Thailand, Indonesia. The dynamics of development of the world hotel industry by regions is analyzed. It was found that a slight decrease in hotel employment in 2019 in all regions except the Middle East and Africa. A constant growth trend and high occupancy rates of accommodation establishments have been recorded in the European and Asia-Pacific region. According to the results of the assessment of the dynamics of monthly hotel occupancy in 2019-2020, a downward trend was established. A study of the dynamics of arrivals of international tourists in the period 2000-2020 and analyzed scenarios for future development. It was found that the results of 2020 are expected to reduce the arrival of international tourists by 70-75%. It may take 2.5 to 4 years for international tourism to return to 2019 levels. The directions of development of the world hotel economy in the conditions of quarantine are generalized. These include the transfer of a significant amount of business activity to the virtual world; use of voice search and voice control; increase the share in the field of services where personal contact is not required; introduction of strict sanitary and epidemiological norms and measures where it is not possible to refuse personal contacts; increasing the robotization of production processes; transition to non-cash financial transactions.

Amostragem de vespas solitárias em diferentes dispositivos artificiais em policultivos, Alagoas – AL

RESUMO: As vespas são insetos reguladores naturais de diversas pragas em cultivos agrícolas, possuindo papel biológico como importantes bioindicadores da qualidade do ambiente. Objetivou-se conhecer populações de vespas solitárias em diferentes dispositivos artificiais em policultivos na região do Agreste do Estado de Alagoas. O estudo concentrou-se em três áreas: Área I – frutíferas e cultivo de fumo (Craíbas – AL); Área II – Viveiro de mudas; Área III – Frutíferas, cultivo de fumo e mata secundária (capoeira), estas duas últimas áreas no município de Arapiraca – AL. Foram instaladas 45 armadilhas (15 armadilhas/Área) distribuídos em diferentes dispositivos e diâmetros: Papel ‘kraft’(5, 7, 9 e 10 mm); Papel cartolina preta (9 mm) e Bambu (3 mm). As amostras foram encaminhadas ao Laboratório de Biologia da UFAL/Campus de Arapiraca-AL para a quantificação e identificação do material. Um total de 29 ninhos foi ocupado (Ni = 105 indivíduos) foi registrado e com elevada taxa de ocupação para área III (1,89%; Ni = 17), registrando apenas duas espécies de vespas: Trypoxylon sp. (74,3%; Ni = 78) da família Crabonidae e Pachodynerus cf. serrulatus (25,7%; Ni = 27), revelando maior preferência de nidificação em ninhos tipo ‘kraft’ nos diâmetros 5 e 7 mm, respectivamente. Na análise do teste qui-quadrado (χ2) com associação existente entre o número de ninhos ocupados e taxa de nidificação para as três áreas estudadas, apresentou uma diferença altamente significativa (<0,0001) na área III, demonstrando maior disponibilidade de recursos para o forrageamento das espécies. Por outro lado, o número reduzido de espécies de vespas nas amostragens pode estar relacionado com o impacto de defensivos químicos e práticas agrícolas, prejudicando os sítios de nidificação, além de prejudicar outros polinizadores locais. Essas informações são relevantes, e um alerta aos produtores locais com o uso moderado de agrotóxicos, conscientizando-os à conservação e qualidade ambiental nas áreas.
 PALAVRAS-CHAVE: Vespoidea, Nidificação, Agroecossistemas

Knowledge and opinions of patients attending a hospital emergency

Background: The high occupancy rate of hospital emergency departments (ED) necessitates the selection of patients whom an excessively long waiting time for medical assistance may result in deterioration of their health condition or pose a threat to life. Medical categorization plays an important role in the identification of such patients. Aim of the study: The aim of this study was to determine the level of knowledge, and opinions, of patients attending the ED regarding the purpose and processes surrounding the use of triage. Material and methods: This study included 123 patients attending the ED of the University Clinical Hospital (UCH) in Opole in the period from January to March 2019. Study participants carried out a questionnaire after leaving the triage room. Results: Most participants (93.50%, n = 115) gave a correct answer to the question of what triage is, and 90.20% (n = 111) gave a correct answer to the question of its purpose. Most patients felt that triage was needed (73.20%, n = 90), and 54.50% (n = 67) felt that ED staff should refer patients without life-threatening conditions to the PHCF (Primary Health Care Facility) or OOHC (Out of Hours Care) unit. Most participants (59.30%, n = 73) were aware of which color to which they had been assigned following medical categorization. Conclusions: The level of knowledge of patients attending the ED regarding the triage process was generally good, but nevertheless ED staff should ensure attendees are provided with information on the urgency category assigned to them and estimated waiting time, as well as information regarding possible delays. Information leaflets or short videos on ED operation and admission procedures may play an important role in the education of patients in waiting rooms.

Admission and Discharge Control in Intensive Care Units

Intensive Care Units (ICUs) are scarce resources that usually operate under high occupancy rates. When faced with limited bed availability, arriving patients are sometimes rejected or admitted by discharging an existing patient early which may result in increased readmission rates or patient/hospital related costs. Yet, there is not a well-defined admission and discharge policy to decrease such adverse consequences. We formulate a comprehensive ICU model with multiple patient types, multiple health stages, and a so-called readmission orbit whose population consists of patients who will seek readmission after an ICU discharge. The ICU model also differentiates first-time and recurring patients. We propose two easy-to-implement heuristic control policies, one based on a Markov Decision Processes model and the other based on a deterministic fluid model. We compare the performances of these policies with the ones of two state-of-the-art policies via discrete-event simulation. According to the numerical results, our proposed policies significantly outperform the state-of-the-art policies by carefully balancing rejection and early-discharge decisions. Moreover, they complement each other since the fluid-based policy performs well in large ICUs that operate in an overloaded regime, while the one-bed policy performs well in small ICUs or ICUs operating in critically or under-loaded regimes.

ПОРІВНЯЛЬНИЙ АНАЛІЗ КЛАСТЕРНИХ ІНСТРУМЕНТІВ ЕКОНОМІЧНОГО РОЗВИТКУ В УКРАЇНІ ТА В'ЄТНАМІ

Comparative analysis of cluster instruments for economic development of Ukraine and Vietnam is carried out. The study showed that the absolute majority of the clusters operating in Ukraine have significant strategic gaps between strategic goals and resources for their implementation. In order to eliminate strategic gaps, a set of practical recommendations has been substantiated, which generally consists of the following main elements: inclusion in the current legislation of the concept of "innovative industrial cluster of the sixth technological order"; providing the subjects of such clusters with innovative tax benefits; provision of concessional lending for intra-cluster innovation projects. In terms of the effectiveness of the use of cluster instruments for economic development, Vietnam is significantly ahead of Ukraine. The highest efficiency of cluster development was achieved in Vietnam for fourteen of the sixteen positions we analyzed, and in Ukraine, the highest efficiency was not achieved for any position. For each of the ten cluster instruments of economic development that are not used in Ukraine, we substantiated the feasibility and effectiveness of their implementation in our state. In order to introduce each of the most important cluster instruments of economic development, an appropriate legislative framework should be created in Ukraine, as well as a system of by-laws for its practical implementation. Vietnam has been well done in the cluster industrial policy. To the end of 2020, there are 260 industrial parks in the whole country (besides, there are some industrial parks acquired licensing but not yet constructed or having planned but not yet approved). Hanoi plans to build 43 industrial clusters in 2021. To ensure efficient operation of industrial clusters, Hanoi would provide supporting policies for enterprises and business households relocating their operation into industrial clusters, while setting up a list of service fees for all industrial clusters in the city. Hanoi plans to further promote investment and higher occupancy rate in industrial clusters, gradually transforming the current management model towards greater efficiency in operation of industrial clusters.

Serial Combination Optimization Method of Packet Transport Network

Packet transport network (PTN) has problems such as waste of resources and low network stability due to the excessive complexity of the existing network or improper network architecture design. The optimization of the transport networks can not only make the network structure more reasonable but also reduce all kinds of unexpected scenarios in the network operation, improving the network efficiency and reducing the failure rate. This research will be optimized from three aspects. (1) In order to solve the problem of the same active and standby routing in the existing network, an optimization algorithm for the same active and standby routing of LSP is proposed. The essence of the optimization algorithm is to search the existing routing using the K‐shortest path (KSP) between two network nodes as protection routing for LSP protection. (2) Aiming at the link with a high CIR bandwidth occupancy rate, a method is completed without adding optical fibers and other physical resources; an optimization method for the committed information rate bandwidth occupancy rate based on the KSP algorithm is proposed. (3) When the PTN ring formation rate is low, the security of the PTN is seriously reduced. In order to solve the problem of low ring formation rate in the network, this paper proposes a ring formation rate optimization scheme for PTN access layer equipment based on network elements accounting income. Through the experimental verification on the mobile PTN in one city, Hubei Province, the combination optimization method can improve the network LSP protection rate by 24%, the CIR bandwidth occupancy rate is reduced by 13.82%, and the nonring forming rate was reduced by 17.9%. This method improved network stability, reducing the risk of failure in service transportation effectively.

Asymmetric regular sampling SPWM method based on tangent approximation algorithm

Objectives In order to improve the quality of sinusoidal waveform output by the ship's high-frequency inverter charging device and reduce the CPU occupancy rate, an asymmetric regular sampling sinusoidal pulse width modulation (SPWM) method based on tangent approximation is proposed. Methods According to the basic principle and calculation method of the asymmetric regular sampling SPWM method based on tangent approximation, a Matlab/Simulink simulation model is built, and then the software algorithm flow that can be used in the high-frequency inverter charging device is designed together with the actual output of the tangent approximation method. The effects are then compared and verified by experiments. Results The simulation results show that under pure resistive load and resistive inductive load, the total harmonic distortion (THD) of the load-end waveform based on tangent approximation method is 2.12% and 2.08%, respectively, and its waveform quality is better than symmetric regular sampling. The experimental results show that the THD of load-end waveform based on the tangent approximation method is significantly lower than the symmetric regular sampling method. When the effective value of the input line voltage is 580 V (the modulation ratio is 0.8), the quality of the output waveform is relatively optimal. Conclusions The asymmetric regular sampling SPWM method based on tangent approximation overcomes the shortcomings of the traditional symmetric regular sampling method, such as the low quality of the output waveform and the traditional asymmetric regular sampling method's high sampling frequency and high CPU occupancy rate. The research results can provide reference for the design of ship's high frequency inverter charging devices.

The Implementation of the Music and Memory Intervention in Nursing Facilities in Virginia

The Music & Memory intervention is a person-centered, non-pharmacologic intervention for people living with dementia. It is considered a personalized music intervention because the playlist comprises music genres that the individual prefers. Music has shown positive effects on behavioral and psychological symptoms of dementia. However, the findings from previous studies are often based on small sample sizes, insufficient descriptions of treatment fidelity, and lack of randomization. To address these issues, we began a randomized controlled trial implementing the Music & Memory intervention in nursing facilities in Virginia with support from the Centers for Medicare and Medicaid (CMS) Civil Money Penalty. We will present our research strategies as well as preliminary results suggesting that nursing facilities with higher occupancy rates are more likely to participate in this type of a program. In addition, study participants with dementia show positive emotional and behavioral reactions when listening to their favorite music.

Instrumentos legais como ferramentas para redução de riscos e desastres a inundações

Inundações urbanas são frequentes, porém com adensamento urbano e a impermeabilização da terra (consequência e probabilidade), tendem a elevar o risco de desastres. Buscando reduzir este risco, o objetivo desta pesquisa é analisar como os instrumentos legais estão potencializando ou mitigando o risco de inundações nas principais cidades da Bacia Hidrográfica do Itajaí. Para alcançar este objetivo, realizou-se uma pesquisa descritiva nos Planos Diretores e em legislações municipais de Rio do Sul, Blumenau e Itajaí, com foco intra-lote, analisando os índices urbanísticos, em especial taxa de ocupação e taxa de permeabilidade. Estes índices foram relacionados com o mapa de zoneamento e quantificados em termos de município, sendo então possível uma análise comparativa. Utilizou-se também o zoneamento dos municípios para uma sobreposição aos mapas de áreas inundáveis. Os resultados demonstram que o município de Itajaí possui as maiores taxas de ocupação permitidas e as menores taxas de permeabilidade exigidas. Em relação as áreas inundáveis, os municípios de Rio do Sul e Itajaí possuem zonas com incentivo a ocupação dentro de áreas suscetíveis a inundações. Além disso, como outras medidas intra-lote para retardar o escoamento superficial de águas pluviais, apenas Blumenau possui legislação específica ao incentivar o uso de "Telhado verde". Portanto, conclui-se que as legislações municipais dos municípios analisados não têm incentivado a sustentabilidade urbana e que seus índices urbanísticos estão contribuindo para a ampliação do risco de desastre a inundações.

Quantification of financial consequences of buildings' ageing: analysis of panel building-level data from the Polish office space market

PurposeRelying on a unique proprietary Polish office market space database, the paper attempts to quantify the impact of buildings' age on the financial performance of real estate assets.Design/methodology/approachPanel econometric modeling was utilized to disentangle the impact of buildings' functional obsolescence and technical deterioration on their long-term financial performance.FindingsIn line with casual empiricism, our findings show a negative associative link between properties' age and potential lease revenue. The concomitant stickiness of service charges presages a possible long-term deterioration of financial outcomes of real estate investments. While older buildings generally have higher occupancy rates, the absorption rates are found to be negatively affected by the properties' age. On the bright side, the elasticity of vacancy rate with respect to rental rates is found to decrease as buildings get older. Further, the rent differential is confirmed to be more pronounced in higher age properties hinting at an existing potential for price discrimination, which may at least partially compensate for stagnant rents.Originality/valueOur empirical results confirm the properties' age to be a statistically significant factor in shaping the long-term performance of real estate assets, which should be better accounted for in financial projections for real estate developments.

Irregular silviculture positively influences multiple bat species in a lowland temperate broadleaf woodland

Changing economics in the 20th century led to losses and fragmentation of semi-natural woodland in Britain and to a reduction in active woodland management with many becoming increasingly neglected, even-aged and with closed canopy. Lack of woodland management is known to contribute to declines in some taxonomic groups, for example birds. However, the response of bats to changes in woodland structure are poorly understood. We compared two measures of bat activity, derived from static acoustic recorders across 120 sample plots in coppice, irregular high forest (uneven-aged, continuous cover) and limited intervention (under-managed, even-aged) management stands, within a large tract of ancient woodland in southern England. Bat species richness was highest in irregular high forest stands, and there were significant differences in occupancy rates for most bat species across stand management types. Coppice recorded low activity of several bat species and irregular high forest showed high occupancy rates, including for Barbastelle Barbastella barbastellus, which is IUCN listed as near threatened. The occupancy rates in stand management types differed for some bat species between mid- and late summer counts, suggesting seasonal variation in habitat use. Within stands, most bat species were associated with opened canopy, lower growing stocks and reduced densities of understorey, and to a lesser extent, with large-girthed trees and presence of deadwood snags. In some cases, species responded to a given habitat variable similarly across the three stand management types, whereas in others, the response differed among stand management types. For example, increased numbers of large-girthed trees benefitted a number of bat species within coppice where these were least common, but not in irregular stands. Irregular silviculture high forest appears to provide many of the structural attributes that positively influence occupancy of several woodland bat species, including Barbastella barbastellus.

Sabatolimab (MBG453) Dose Selection and Dose-Response Analysis in Myelodysplastic Syndrome (MDS)/Acute Myeloid Leukemia (AML): Population Pharmacokinetics (PK) Modeling and Evaluation of Clinical Efficacy/Safety By Dose

Sabatolimab (MBG453) Dose Selection and Dose-Response Analysis in Myelodysplastic Syndrome (MDS)/Acute Myeloid Leukemia (AML): Population Pharmacokinetics (PK) Modeling and Evaluation of Clinical Efficacy/Safety By Dose

Biomonitoring of metals in inhabitants of Northern Chile: implications of surveillance in areas with historical exposures

Background: The presence of toxic metals in human populations is strongly associated with chronic diseases and should be monitored especially in communities with a history of chronic exposures as occurs in northern Chile.Objective: to establish concentrations and prevalence of exposure to metals in residents of the city of Antofagasta, Chile, and its main risk factors.Methods: a cross-sectional study in Antofagasta was made. The sample (1203 adults) had populational representability at the city level. Sociodemographic information, health status, and sources of exposure to metals were collected in the participants. Urinary Inorganic Arsenic (InAs), Cadmium (Cd), Chromium (Cr) and Mercury (Hg) levels, and Lead (Pb) in blood were measured using NIOSH methodology by Inductively coupled plasma atomic emission spectroscopy (ICP-AES).Results:The sample had an average age of 42.7 years, with an average residence time in the city of 30 years, predominantly women (54.5%), high smoking (51.5%), high occupation rate in mining activities (22.6%).Using cutoff used by the health authorities (35µg /L for urinary InAs, the prevalence was 8% in adults and 12.3% in children. However, 75% of the population has levels below 21.9 µg / L. The main factors associated with high levels of urinary inorganic arsenic in adults were sex (β= 3.12, IC 95% 0.2-6.05 for males) and low schooling (β= 7.1, IC 95% 0.4-14.6 in people having less 8 y of education). People residing more than 500 meters from fixed sources had higher InAs levels. Other metals are below risk levels defined by health authorities.Conclusions It is urgent that in this city all the sources related to InAs must be verified and develop social interventions and environmental health surveillance in order to reduce involuntarily exposure to this metalloid.

The Burden of Gastroenteritis Outbreaks in Long-Term Care Settings in Philadelphia, 2009–2018

Background: Gastroenteritis causes significant morbidity and mortality in long-term care facility (LTCF) residents, a growing population within the United States. Methods: We conducted a retrospective cross-sectional study in LTCFs in Philadelphia County from 2009 to 2018. Outbreak characteristics and interventions were extracted from Philadelphia Department of Public Health’s (PDPH) database, and quality data on all LTCFs was extracted from the CMS Nursing Home Compare database. Results: We identified 121 gastroenteritis outbreaks in 49 facilities. Numbers of affected patients ranged from 2 to 211 patients (median patient attack rate, 17%). Staff were reported ill in 94 outbreaks (median staff attack rate, 5%). Outbreak facilities were associated with higher occupancy rates (91% vs 88%; P = .033) and total bed numbers (176 vs 122; P = .071) when compared to nonoutbreak facilities. Higher rates of staff illness were associated with prolonged outbreaks (13% vs 4%; P < .001) and higher patient illness rates (9% vs 4%; P = .012). Prolonged outbreaks were associated with lower frequency of cohorting for outbreak management (13% vs 41%; P = .046). Conclusions: This study is the largest published analysis of gastroenteritis outbreaks in LTCFs. Facility characteristics and staff disease 20 activity were associated with more severe outbreaks. Heightened surveillance for gastrointestinal symptoms among staff and increased 21 use of cohorting might reduce the risk of prolonged gastroenteritis outbreaks in LTCF.Funding: NoneDisclosures: None

A review on development of offshore wind energy conversion system

Wind energy conversion system, aiming to convert mechanical energy of air flow into electrical energy has been widely concerned in recent decades. According to the installation sites, the wind energy conversion system can be divided into land-based wind conversion system and offshore wind energy conversion (OWEC) system. Compared to land-based wind energy technology, although OWEC started later, it has attracted more attentions due to its significant advantages in sufficient wind energy, low wind shear, high power output and low land occupancy rate. In this paper, the principle of wind energy conversion and the development status of offshore wind power in the world are briefly introduced at first. And then, the advantages and disadvantages of several offshore wind energy device (OWED), such as horizontal axis OWED, vertical axis OWED and cross axis OWED are compared. Subsequently, several major constraints, such as complex marine environment, deep-sea power transmission and expensive cost of equipment installation faced by offshore wind conversion technology are presented and comprehensively analysed. Finally, based on the summary and analysis of some emerging technologies and the current situation of offshore wind energy utilization, the development trend of offshore wind power is envisioned. In the future, it is expected to witness multi-energy complementary, key component optimization and intelligent control strategy for smooth energy generation of offshore wind power systems.

에이스호텔의 건축차별화 전략연구

This study is focused on the differentiation strategy of ‘Ace Hotel’, ‘community through interaction’, a concept that is not considered by the existing theoretical classification in architectural plan of hotel. The hotel has been built in the same concept and strategy in 11 regions over the past 20 years, showing a high occupancy rate of 80-95%. Through this study, the identification strategy in the architectural plan of the Ace Hotel was identified as 1.The premise of urban regeneration in the site selection, and the possibility of cultural community development as an important factor. 2. Regeneration of peripherality and past time 3. Expansion of shared boundaries. 4. Collaboration through participation of both locals and experts. It is expected that the purpose of this study will be realized by contributing to this differentiation in the planning and planning process of hotel architectural plan in the future.

The burden of gastroenteritis outbreaks in long-term care settings in Philadelphia, 2009-2018.

Gastroenteritis causes significant morbidity and mortality in long-term care facility (LTCF) residents, a growing population within the United States. We set out to better understand gastroenteritis outbreaks in LTCF by identifying outbreak and facility characteristics associated with outbreak incidence as well as outbreak duration and size. We conducted a retrospective cross-sectional study on LTCFs in Philadelphia County from 2009 to 2018. Outbreak characteristics and interventions were extracted from Philadelphia Department of Public Health (PDPH) database and quality data on all LTCFs was extracted from Centers for Medicare and Medicaid Services Nursing Home Compare database. We identified 121 gastroenteritis outbreaks in 49 facilities. Numbers of affected patients ranged from 2 to 211 patients (median patient illness rate, 17%). Staff were reported ill in 94 outbreaks (median staff illness rate, 5%). Outbreak facilities were associated with higher occupancy rates (91% vs 88%; P = .033) and total bed numbers (176 vs 122; P = .071) compared to nonoutbreak facilities. Higher rates of staff illness were associated with prolonged outbreaks (13% vs 4%; P < .001) and higher patient illness rates (9% vs 4%; P = .012). Prolonged outbreaks were associated with lower frequency of cohorting for outbreak management (13% vs 41%; P = .046). This study is the largest published analysis of gastroenteritis outbreaks in LTCFs. Facility characteristics and staff disease activity were associated with more severe outbreaks. Heightened surveillance for gastrointestinal symptoms among staff and increased use of cohorting might reduce the risk of prolonged gastroenteritis outbreaks in LTCF.

Interplay Between Cation Distribution and Magnetic Properties in MgM0.5Mn1.5O4 (M = Al, Ga) and Al1.5Mn1.5O4 Spinels

The polycrystalline samples of Al1.5Mn1.5O4, MgAl0.5Mn1.5O4 and MgGa0.5Mn1.5O4 were prepared using a standard ceramic method and characterized by X-ray diffraction and magnetic measurements. The cationic distributions were determined by the combination of the Rietveld refinement and the tabulated cation-oxygen distances in spinel compounds. The results obtained were compared with those calculated using a thermodynamic calculation according to the O’Neill model. The Al1.5Mn1.5O4 compound is characterized by its cationic distribution with a high occupancy rate of the magnetic ions Mn2+ in the A sites, in agreement with the experimental magnetic moment. This compound presents a ferrimagnetic behavior at T < 23.5 K. The MgAl0.5Mn1.5O4 and MgGa0.5Mn1.5O4 compounds have almost the same distribution of magnetic manganese cations in both A and B sites, with a weak presence of the magnetic ions Mn2+ in the A sites, justified by the refinement Rietveld, thermodynamic calculation and the hyperbolic form of the inverse magnetic susceptibility above 23.2 K. Both compounds have almost the same magnetic behavior at low temperature T < 23.2 K, typical of a spin glass. This behavior is attributed to the strong presence of diamagnetic ions on the A sites and the magnetic disorder in B sites.

WHIPLASH INJURY MECHANISMS OF CAR REAR OCCUPANTS: A REVIEW

Whiplash injury due to low severity vehicles crash is a global problem. The injury has long-term clinical and biomechanical implications. Since the mid-1960s, injury statistics have continuously revealed that females face a higher risk of suffering the injury category compare to males. Besides, in a frontal crash, the injury measures from the adult rear dummies were mainly higher than the same size dummies located in driver and front occupant seat. However, most regulations and user crash tests have focused on vehicle drivers and front-seat passenger due to high occupancy and mortality rates in the front seat. In this paper, mechanisms of whiplash injury were reviewed to contribute a further inclusive understanding of human impact reaction, variability quantification, validation, and prevention. The objective of this study is to develop a new design of head restraint (HR) for car rear occupants. In order to raise consideration whiplash injury and prevention mechanisms, impacts are simulated with computer modelling (Ls-Dyna simulation) and validated using Matlab. Therefore, a review of these injury mechanisms indicates the development of new anti-whiplash technology in the automotive safety area is necessary.