Examining emotional and behavioural trajectories in siblings of children with life-limiting conditions.

BACKGROUND: Healthy siblings of children with life-limiting conditions often experience emotional and behavioural struggles over the course of the ill child's condition(s). Resources to support these siblings are limited due to a lack of understanding about their needs. Therefore, this study was designed to characterize the emotional and behavioural trajectories among siblings of children with progressive, life-limiting genetic, metabolic, or neurological conditions over a 12-month observation period. METHODS: Seventy siblings were recruited from a large-survey based study (Charting the Territory) that examined the bio-psychosocial health outcomes of parents and siblings. Linear mixed effect models were used to assess the association between siblings' emotions and behaviour trajectories and selected demographic variables. Siblings' emotions and behaviour were measured with Child Behaviour Checklist (CBCL). RESULTS: Siblings' mean age was 11.2 years at baseline and Internalizing, Externalizing, and Total Behaviour Problems mean scores were within normal ranges across time. However, 7-25% of siblings had scores within the clinical range. Brothers had higher levels of Internalizing Problems than sisters, whereas sisters had higher levels of Externalizing Problems than brothers. When treatment was first sought for the ill child less than a year prior to study participation, siblings had higher levels of Internalizing and Externalizing Problems compared with siblings who participated more than one year after treatment was sought. CONCLUSION: Healthy siblings experience emotional and behavioural problems early in the child's disease trajectory. Although these problems improve with time, our findings show that brothers and sisters experience different types of challenges. Therefore, timely support for siblings is important as they navigate through the uncertainties and challenges.

A novel classification system for research reporting in rare and progressive genetic conditions.

AIM: To create a classification system for severe, rare, and progressive genetic conditions for use in research reporting. METHOD: A modified Delphi consensus technique was used to create and reach agreement on a new system of condition categories. Interrater reliability was tested via two rounds of an online survey whereby physicians classified a subset of conditions using our novel system. Overall percentage agreement and agreement above chance were calculated using Fleiss' kappa (κ). RESULTS: Eleven physicians completed the first Delphi, with an overall agreement of 76.4%, the κ value was 0.57 (95% confidence interval 0.51-0.63), indicating moderate agreement (0.41-0.60) above chance. Based on the first survey several categories were described in more detail. The second survey confirmed a classification system with 12 categories, with an overall percentage agreement among the participants of 82.6%. The overall mean κ value was 0.71 (95% confidence interval 0.65-0.77), indicating substantial agreement (0.61-0.80). INTERPRETATION: Our new system was useful in categorizing a broad range of rare childhood diseases and may be applicable to other rare disease studies; further validation in larger cohorts is required. WHAT THIS PAPER ADDS: This novel 12-category classification system can be used in research reporting in rare and progressive genetic conditions.

UN NOVEDOSO SISTEMA DE CLASIFICACIÓN PARA REPORTAR CONDICIONES GENÉTICAS RARAS Y PROGRESIVAS: OBJETIVO: Crear un sistema de clasificación para condiciones genéticas severas, raras y progresivas para uso en informes de investigación METODO: Se utilizó una técnica de consenso de Delphi modificada para crear y llegar a un acuerdo sobre un nuevo sistema de categorías de condiciones genéticas. La confiabilidad del sistema entre evaluadores se corroboró por medio de dos rondas de encuestas en linea en la que los médicos clasificaron un subconjunto de condiciones utilizando nuestro nuevo sistema. El porcentaje general de acuerdo y el acuerdo sobre la probabilidad se calcularon utilizando el kappa (κ) de Fleiss. RESULTADOS: Once médicos completaron el primer Delphi, con un acuerdo general de 76,4%, el valor de κ fue 0,57 (intervalo de confianza del 95% 0,51-0,63), lo que indica un acuerdo moderado (0,41-0,60). Sobre la base de la primera encuesta se describieron con más detalle varias categorías. La segunda encuesta confirmó un sistema de clasificación con 12 categorías, con un porcentaje de acuerdo general entre los participantes del 82,6%. El valor medio global de κ fue de 0,71 (intervalo de confianza del 95%: 0,65 a 0,77), lo que indica un acuerdo alto (0,61 a 0,80). INTERPRETACIÓN: Nuestro nuevo sistema de clasificación fue útil para categorizar una amplia gama de enfermedades infantiles raras y puede ser aplicable a otros estudios de enfermedades raras. Sugerimos validación adicional en cohortes más numerosas.

UM NOVO SISTEMA DE CLASSIFICAÇÃO PARA PESQUISAS RELATANDO CONDIÇÕES GENÉTICAS RARAS E PROGRESSIVAS: OBJETIVO: Criar um sistema de classificação para condições genéticas severas, raras e progressivas, a ser usado em relatos de pesquisas. MÉTODO: Uma técnica de consenso Delphi modificada foi usada para criar e obter concordância sobre um novo sistema de categorias de condições. A confiabilidade inter-examinadores foi testada em dois momentos por meio de um questionário virtual, pelo qual médicos classificaram um subgrupo de condições usando nosso novo sistema. A porcentagem geral de concordância e a concordância maior que o acaso foram calculadas usando kappa (k) de Fleiss. RESULTADOS: Onze médicos completaram o primeiro Delphi, com concordância geral de 76,4%, valor de k de 0,57 (intervalo de confiança a 95% 0,51-0,63), indicando concordância moderada (0,41-0,60) maior do que o acaso. Com base no primeiro questionário várias categorias foram descritas com maior detalhe. O segundo questionário confirmou um sistema de classificação com 12 categorias, com porcentagem geral de concordância entre os participantes de 82,6%. O valor de k médio geral foi 0,71 (intervalo de confiança a 95% 0,65-0,77), indicando concordância substancial (0,61-0,80). INTERPRETAÇÃO: Nosso novo sistema foi útil em categorizar uma ampla variedade de doenças da infância, e pode ser aplicável ao estudo de outras doenças raras; continuar a validação em coortes maiores é necessário.

Siblings' voices: A prospective investigation of experiences with a dying child.

Sibling relationships reflect a unique childhood bond, thus the impact on a sibling when a child is seriously ill or dying is profound. We conducted a prospective, longitudinal, qualitative study over 2 years using interpretive descriptive methodology to understand siblings' perspectives when a brother or sister was dying at home or in hospital. The insights from the 10 siblings revealed complex experiences, both personal and with the ill child, their families, and peers. These experiences were paradoxically sources of strain and of support, revealing the importance of validation and normalization in assisting siblings to successfully navigate the experience.

What Would Be Really Helpful but Nobody Ever Tells You: Five Key Recommendations Derived From Lessons Learned During a Qualitative Study in Clinical Settings.

The complexity of qualitative research can lead to a less thorough analysis than would be ideal. Even experienced researchers can become entwined in the myriad of decisions that must be made. Descriptions of qualitative approaches in numerous textbooks and published articles often lack sufficient details to help a researcher surface from the entanglements, especially when conducting studies in clinical settings. In this paper, we share our experiences of navigating some "real-world" issues in doing qualitative research. We describe five key, practical recommendations to assist researchers in preventing, or at least alleviating, some of the challenges that researchers may face, particularly ones that limit in-depth analysis: (1) conduct a pilot study, (2) hire a research analyst, (3) engage the "right" team, (4) attend to team cohesion, and (5) conduct conceptual analysis through a process of "node expansion."

Siblings of Children With a Complex Chronic Health Condition: Maternal Posttraumatic Growth as a Predictor of Changes in Child Behavior Problems.

Objective: The present study examined the role of maternal posttraumatic growth in changes in behavioral problems among the siblings of children with complex chronic health conditions. Methods: Data were collected from a sample of 70 siblings from 58 families with at least one child diagnosed with a life-threatening genetic, metabolic, or neurological condition. Every 6 months for up to 4 years, sibling behavior problems were assessed through both parent-reports and youth self-reports. At each visit, mothers also completed self-reports of posttraumatic growth. Results: Time-lagged multilevel regression analyses revealed that higher levels of maternal posttraumatic growth predicted subsequent declines in parent-reported internalizing, externalizing, and total behavior problems among healthy siblings. These findings were partially replicated using youth self-reports of their own behavior problems. Conclusion: The findings suggest that the benefits of posttraumatic growth may extend beyond the self to other family members, particularly to children in the family.

Best Practice in Provider/Parent Interaction.

In this 3-year prospective grounded theory study in three pediatric settings, we aimed to develop a conceptualization of best practice health care providers (BPHCPs) in interaction with parents of children with complex, chronic, life-threatening conditions. Analysis of semistructured interviews with 34 parents and 80 health care professionals (HCPs) and 88 observation periods of HCP/parent interactions indicated that BPHCPs shared a broad worldview; values of equity, family-centered care, and integrity; and a commitment to authentic engagement. BPHCPs engaged in direct care activities, in connecting behaviors, and in exquisitely attuning to particularities of the situation in the moment, resulting in positive outcomes for parents and HCPs. By focusing on what HCPs do well, findings showed that not only is it possible for HCPs to practice in this way, but those who do so are also recognized as being the best at what they do. We provide recommendations for practice and initial and ongoing professional education.

Initial development and psychometric testing of an instrument to measure the quality of children's end-of-life care.

BACKGROUND: The field of pediatric palliative care is hindered by the lack of a well-defined, reliable, and valid method for measuring the quality of end-of-life care. METHODS: The study purpose was to develop and test an instrument to measure mothers' perspectives on the quality of care received before, at the time of, and following a child's death. In Phase 1, key components of quality end-of-life care for children were synthesized through a comprehensive review of research literature. These key components were validated in Phase 2 and then extended through focus groups with bereaved parents. In Phase 3, items were developed to assess structures, processes, and outcomes of quality end-of-life care then tested for content and face validity with health professionals. Cognitive testing was conducted through interviews with bereaved parents. In Phase 4, bereaved mothers were recruited through 10 children's hospitals/hospices in Canada to complete the instrument, and psychometric testing was conducted. RESULTS: Following review of 67 manuscripts and 3 focus groups with 10 parents, 141 items were initially developed. The overall content validity index for these items was 0.84 as rated by 7 health professionals. Based on feedback from health professionals and cognitive testing with 6 parents, a 144-item instrument was finalized for further testing. In Phase 4, 128 mothers completed the instrument, 31 of whom completed it twice. Test-retest reliability, internal consistency, and construct validity were demonstrated for six subscales: Connect With Families, Involve Parents, Share Information With Parents, Share Information Among Health Professionals, Support Parents, and Provide Care at Death. Additional items with content validity were grouped in four domains: Support the Child, Support Siblings, Provide Bereavement Follow-up, and Structures of Care. Forty-eight items were deleted through psychometric testing, leaving a 95-item instrument. CONCLUSIONS: There is good initial evidence for the reliability and validity of this new quality of end-of-life care instrument as a mechanism for evaluative feedback to health professionals, health systems, and policy makers to improve children's end-of-life care.

Charting the Territory: Children and families living with progressive life-threatening conditions.

OBJECTIVES: To increase awareness of the topic of paediatric palliative care among practicing physicians in Canada by exploring the impact of a child's neurological or rare genetic life-threatening condition on the affected child and his/her parents. METHODS: Cross-sectional, baseline results from an observational, longitudinal study, Charting the Territory, which followed 275 children and 390 parents from 258 families. Parents completed multiple surveys, for themselves and their child. RESULTS: These children had a high symptom burden. The three most common symptoms were pain, sleep problems and feeding difficulties; on average, they had 3.2 symptoms of concern. Despite analgesic use, the frequency of pain episodes and distress were invariant over time, suggesting that treatments were not successful. Parents experienced anxiety, depression and burden; at the same time they also reported positive life change and a high degree of spirituality. The child's condition resulted in parental changes in living arrangements, work status and hours devoted to caregiving. Nearly two-thirds of families were involved with a palliative care team; the size of the community in which a family resided did not make a significant difference in such involvement. CONCLUSIONS: These families experience many challenges, for the patient, other individual members and the family as a whole. At least some of these challenges may be alleviated by early and organized palliative care. Effective interventions are needed to enhance symptom management for the ill child and to alleviate the various negative impacts on the family.

OBJECTIFS: Mieux faire connaître les soins palliatifs aux médecins en exercice du Canada en explorant les effets de maladies neurologiques ou génétiques rares au potentiel fatal sur l'enfant atteint et ses parents. MÉTHODOLOGIE: Les auteurs publient les résultats transversaux et initiaux d'une étude d'observation longitudinale, Explorer de nouveaux territoires, auprès de 275 enfants et de 390 parents de 258 familles. Les parents ont rempli de multiples sondages en leur nom et au nom de leur enfant. RÉSULTATS: Les enfants présentaient un lourd fardeau de symptômes. Les trois plus fréquents étaient la douleur, les troubles du sommeil et les problèmes d'alimentation. En moyenne, ils avaient 3,2 symptômes inquiétants. Malgré l'utilisation d'analgésiques, la fréquence d'épisodes de douleur et de détresse ne changeait pas au fil du temps, ce qui laisse supposer l'échec des traitements. Les parents ressentaient de l'anxiété, de la dépression et un fardeau, mais signalaient également un changement de vie positif et une spiritualité marquée. En raison de l'état de l'enfant, les parents modifiaient leur mode de vie, leur statut professionnel et les heures consacrées aux soins. Près des deux tiers des familles recouraient à une équipe de soins palliatifs, sans que la dimension de leur communauté y ait une incidence significative. CONCLUSIONS: Ces familles éprouvaient de nombreux problèmes, tant pour les patients et les autres membres de la famille que pour l'ensemble de la famille. Au moins certains problèmes peuvent être atténués par des soins palliatifs instaurés rapidement et organisés. Des interventions efficaces s'imposent pour améliorer la prise en charge des symptômes de l'enfant et en réduire les divers effets négatifs pour la famille.

Differences on psychosocial outcomes between male and female caregivers of children with life-limiting illnesses.

This secondary analysis of data examined the psychosocial outcomes of meaning in caregiving, self-esteem, optimism, burden, depression, spirituality, and posttraumatic growth in 273 parents caring for children with life-limiting illnesses to (a) determine if there were gender differences and (b) identify gender-specific correlations among these outcomes. Findings suggest that significant gender differences exist. Women reported higher average scores compared with men for meaning in caregiving, depression, burden, and posttraumatic growth and lower average scores for optimism. Correlations also revealed some significant differences. Health care professionals need to be aware of gender differences and tailor their interventions appropriately.

Charting the Territory: End-of-Life Trajectories for Children With Complex Neurological, Metabolic, and Chromosomal Conditions.

CONTEXT: For parents, family, or clinicians of children with rare life-threatening conditions, there is little information regarding likely symptoms, illness trajectory, and end-of-life care. OBJECTIVES: This descriptive analysis of a bereaved cohort recruited in the charting the territory study describes patient characteristics, symptoms, use of medications, discussion of resuscitation orders, and care provided preceding and during the end of life. METHODS: Of the 275 children enrolled in the Charting the Territory study, 54 died between 2009 and 2014. Baseline demographic information, symptoms, interventions, and medical information were collected via chart review, interviews, and surveys. RESULTS: Fifty-one of the 54 children had complete medical records. Of the seven symptoms evaluated, children were found to have an increase in median symptoms from baseline (n = 2) to time of death (n = 3). Opioids were used in the last 48 hours of life in 29 (56.9%) children, whereas only eight (15.7%) were receiving opioids at baseline. Do Not Attempt Resuscitation orders were in place at baseline in 17 (33.3%) children, increasing to 33 (64.7%) at time of death. Death occurred in a hospice setting in 16 (31.4%) children. CONCLUSION: Although much emphasis on pediatric palliative care has been on supportive treatment and symptom management, when faced with a lack of sound understanding of a rare illness, the mode of care can often be reactive and based on critical needs. By developing greater knowledge of symptoms and illness trajectory, both management and care can be more responsive and anticipatory, thereby helping ease illness burden and suffering.

Optimising the process for conducting scoping reviews.

Knowledge synthesis constitutes a key part of evidence-based medicine and a scoping review is a type of knowledge synthesis that maps the breadth of literature on a topic. Conducting a scoping review is resource intensive and, as a result, it can be challenging to maintain best practices throughout the process. Much of the current guidance describes a scoping review framework or broad ways to conduct a scoping review. However, little detailed guidance exists on how to complete each stage to optimise the process. We present five recommendations based on our experience when conducting a particularly challenging scoping review: (1) engage the expertise of a librarian throughout the process, (2) conduct a truly systematic search, (3) facilitate communication and collaboration, (4) explore new tools or repurpose old ones, and (5) test every stage of the process. These recommendations add to the literature by providing specific and detailed advice on each stage of a scoping review. Our intent is for these recommendations to aid other teams that are undertaking knowledge synthesis projects.

Designing and implementing a longitudinal study of children with neurological, genetic or metabolic conditions: charting the territory.

BACKGROUND: Children with progressive metabolic, neurological, or chromosomal conditions and their families anticipate an unknown lifespan, endure unstable and often painful symptoms, and cope with erratic emotional and spiritual crises as the condition progresses along an uncertain trajectory towards death. Much is known about the genetics and pathophysiology of these diseases, but very little has been documented about the trajectory of symptoms for children with these conditions or the associated experience of their families. A longitudinal study design will help to close this gap in knowledge. METHODS/DESIGN: Charting the Territory is a longitudinal descriptive, correlational study currently underway with children 0-19 years who are diagnosed with progressive neurological, metabolic, or chromosomal conditions and their families. The purpose of the study is to determine and document the clinical progression of the condition and the associated bio-psychosocial-spiritual experiences of the parents and siblings age 7-18 years. Approximately 300 families, both newly diagnosed children and those with established conditions, are being recruited in six Canadian cities. Children and their families are being followed for a minimum of 18 months, depending on when they enroll in the study. Family data collection will continue after the child's death if the child dies during the study period. Data collection includes monthly parental assessment of the child's symptoms; an annual functional assessment of the child; and completion of established instruments every 6 months by parents to assess family functioning, marital satisfaction, health status, anxiety, depression, stress, burden, grief, spirituality, and growth, and by siblings to assess coping and health. Impact of participation on parents is assessed after 1 year and at the end of the study. Chart reviews are conducted at enrollment and at the conclusion of the study or at the time of the child's death. DISCUSSION: Knowledge developed from this study will provide some of the first-ever detailed descriptions of the clinical symptom trajectory of these non-curable progressive conditions and the bio-psychosocial-spiritual aspects for families, from diagnosis through bereavement. Information about developing and implementing this study may be useful to other researchers who are interested in designing a longitudinal study.

Supportive care needs of individuals with lung cancer.

The main purpose of this study was to identify the range of supportive care needs of patients diagnosed with lung cancer who attended an outpatient, regional cancer centre. Lung cancer has more than a physical impact on those who are diagnosed with the disease, yet relatively little has been reported on their needs beyond those for physical symptom management. A total of 88 patients participated in this study by completing a self-report questionnaire. The data provided clear indication that a range of needs, both physical and psychosocial, exist for this group of patients and, furthermore, remain unmet. Lack of energy, pain, and concern about those close to them were reported most frequently. Patients also expressed distress because of difficulty managing their needs and many indicated wanting help to cope with the challenges they were experiencing. However, a sizeable proportion (45% to 58%) indicated they did not want help from staff at the cancer centre for some need items despite considerable distress arising from those remaining unmet (e.g., lack of energy, fears about cancer spreading, not being able to do the things you used to do). Suggestions for practice and future research are offered to improve the care for this group of patients.

Identifying supportive care needs of women with ovarian cancer.

Women diagnosed with ovarian cancer may experience many shortterm and long-term effects from cancer and its treatment. Cancer has more than a physical impact, yet there is a lack of information about the types of needs these women have and whether they want help in meeting their needs. The main purpose of this cross-sectional, descriptive study was to identify the supportive care needs (physical, emotional, social, informational, spiritual, psychological and practical) of women with ovarian cancer who attended a comprehensive, outpatient cancer centre. A further purpose was to determine if women wanted assistance in meeting those needs. A total of 50 women diagnosed with ovarian cancer participated in this study by completing a self-report questionnaire (The Supportive Care Needs Survey). The data indicated that a range of supportive care needs remained unmet for this patient group. Eight of the top 10 most frequently reported needs were psychosocial, such as fears about the cancer returning or spreading. The women also expressed a range of difficulty in managing their needs. However, despite this reality, significant numbers of women indicated they did not wish to have assistance from the clinic staff with some needs. Suggestions for practice and future research are offered to assist oncology nurses in providing care to these women.

Scoping review of symptoms in children with rare, progressive, life-threatening disorders.

BACKGROUND: Q3 conditions are progressive, metabolic, neurological or chromosomal childhood conditions without a cure. Children with these conditions face an unknown lifespan as well as unstable and uncomfortable symptoms. Clinicians and other healthcare professionals are challenged by a lack of evidence for symptom management for these conditions. AIMS: In this scoping review, we systematically identified and mapped the existing literature on symptom management for children with Q3 conditions. We focused on the most common and distressing symptoms, namely alertness, behavioural problems, bowel incontinence, breathing difficulties, constipation, feeding difficulties, sleep disturbance, temperature regulation, tone and motor problems and urinary incontinence. For children with complex health conditions, good symptom management is pertinent to ensure the highest possible quality of life. METHODS: Scoping review. Electronic database searches in Ovid MEDLINE, Embase and CINAHL and a comprehensive grey literature search. RESULTS: We included 292 studies in our final synthesis. The most commonly reported conditions in the studies were Rett syndrome (n=69), followed by Cornelia de Lange syndrome (n=25) and tuberous sclerosis (n=16). Tone and motor problems were the most commonly investigated symptom (n=141), followed by behavioural problems (n=82) and sleep disturbance (n=62). CONCLUSION: The evidence for symptom management in Q3 conditions is concentrated around a few conditions, and these studies may not be applicable to other conditions. The evidence is dispersed in the literature and difficult to access, which further challenges healthcare providers. More research needs to be done in these conditions to provide high-quality evidence for the care of these children.

Research priorities in pediatric palliative care: a Delphi study.

BACKGROUND: Pediatric palliative care is increasingly recognized to be a specialized type of care requiring specific skills and knowledge, yet, as found in several countries, there is little available research evidence on which to base care. OBJECTIVES: The goal of the project was to achieve consensus among palliative care practitioners and researchers regarding the identification of pertinent lines of research. METHOD: A Delphi technique was used with an interdisciplinary panel (n = 14-16) of researchers and frontline clinicians in pediatric palliative care in Canada. RESULTS: Four priority research questions were identified: What matters most for patients and parents receiving pediatric palliative services? What are the bereavement needs of families in pediatric palliative care? What are the best practice standards in pain and symptom management? What are effective strategies to alleviate suffering at the end of life? CONCLUSIONS: These identified priorities will provide guidance and direction for research efforts in Canada, and may prove useful in providing optimal care to patients and families in pediatric palliative care.

Families' transition to a Canadian paediatric hospice. Part two: results of a pilot study.

The results from a pilot study are reported in this article, part two of a two-part paper. The experiences of parents (six mothers and two fathers) are described as their families transitioned to the Canuck Place Children's Hospice (CPHC) in Canada. The perspectives of non-hospice health care professionals (n=4) involved in the child's care are explored. Data were gathered through audio-taped, semi-structured interviews. Initially, parents and health professionals were unaware that the hospice provided more than just end-of-life services. Parents began to consider hospice care when something changed in their lives that forced them to see things differently. This became the impetus for recognizing that CPCH might be a resource for their family. The prospect of respite care was usually the deciding factor in applying to the hospice. Parents reported benefits of hospice respite for themselves and the whole family. Recommendations for practice and future research are offered, including discussion about the feasibility of the study procedures.

Families' transition to a Canadian paediatric hospice. Part one: planning a pilot study.

This article describes the rationale for planning and conducting a qualitative pilot study about families' transition to a Canadian paediatric hospice. Discussion includes: background information and a literature review pertinent to the study; debate around the term 'hospice' versus 'palliative care'; the different and unique needs of children requiring a palliative approach compared with adult hospice patients; and information about planning and beginning the study, including the rationale for a pilot, details about the study site, recruitment and procedures, and data collection and analysis. The results from the pilot study, as well as implications for practice and research are reported in part two.

Parents' and children's perspectives of a children's hospice bereavement program.

The provision of some form of bereavement services is an integral part of any pediatric hospice program. The Canuck Place hospice program has offered bereavement services since it began in 1995. A mixed-method evaluation of the impact of the Canuck Place program on the families it served during its first two-and-a-half years of operation was conducted. The bereavement services reviewed included follow-up care for families, and bereavement support groups for children and their parents. Eight children were interviewed in the initial phase, and nine completed a survey questionnaire; 28 parents rated their level of satisfaction with various aspects of their experience with the parent support group. Findings indicated that the follow-up component of the program was well-received by family members. When assessing their group experiences, children and parents most appreciated the support and understanding they received, the freedom to express themselves, a diminished sense of isolation, and the normalization of their emotions. Practical considerations when offering bereavement support groups are discussed in this paper.