A 'rich-get-richer' mechanism drives patchy dynamics and resistance evolution in antibiotic-treated bacteria.

Bacteria in nature often form surface-attached communities that initially comprise distinct subpopulations, or patches. For pathogens, these patches can form at infection sites, persist during antibiotic treatment, and develop into mature biofilms. Evidence suggests that patches can emerge due to heterogeneity in the growth environment and bacterial seeding, as well as cell-cell signaling. However, it is unclear how these factors contribute to patch formation and how patch formation might affect bacterial survival and evolution. Here, we demonstrate that a 'rich-get-richer' mechanism drives patch formation in bacteria exhibiting collective survival (CS) during antibiotic treatment. Modeling predicts that the seeding heterogeneity of these bacteria is amplified by local CS and global resource competition, leading to patch formation. Increasing the dose of a non-eradicating antibiotic treatment increases the degree of patchiness. Experimentally, we first demonstrated the mechanism using engineered Escherichia coli and then demonstrated its applicability to a pathogen, Pseudomonas aeruginosa. We further showed that the formation of P. aeruginosa patches promoted the evolution of antibiotic resistance. Our work provides new insights into population dynamics and resistance evolution during surface-attached bacterial growth.

Development of an eHealth Tool for Capturing and Analyzing the Immune-related Adverse Events (irAEs) in Cancer Treatment.

Introduction: Immunotherapy has revolutionized the treatment of many different types of cancer, but it is associated with a myriad of immune-related adverse events (irAEs). Patient-reported outcome (PRO) measures have been identified as valuable tools for continuously collecting patient-centered data and are frequently used in oncology trials. However, few studies still research an ePRO follow-up approach on patients treated with Immunotherapy, potentially reflecting a lack of support services for this population. Methods: The team co-developed a digital platform (V-Care) using ePROs to create a new follow-up pathway for cancer patients receiving immunotherapy. To operationalize the first 3 phases of the CeHRes roadmap, we employed multiple methods that were integrated throughout the development process, rather than being performed in a linear fashion. The teams employed an agile approach in a dynamic and iterative manner, engaging key stakeholders throughout the process. Results: The development of the application was categorized into 2 phases: "user interface" (UI) and "user experience" (UX) designs. In the first phase, the pages of the application were segmented into general categories, and feedback from all stakeholders was received and used to modify the application. In phase 2, mock-up pages were developed and sent to the Figma website. Moreover, the Android Package Kit (APK) of the application was installed and tested multiple times on a mobile phone to proactively detect and fix any errors. After resolving some technical issues and adjusting errors on the Android version to improve the user experience, the iOS version of the application was developed. Discussion: By incorporating the latest technological developments, V-Care has enabled cancer patients to have access to more comprehensive and personalized care, allowing them to better manage their condition and be better informed about their health decisions. These advances have also enabled healthcare professionals to be better equipped with the knowledge and tools to provide more effective and efficient care. In addition, the advances in V-Care technology have allowed patients to connect with their healthcare providers more easily, providing a platform to facilitate communication and collaboration. Although usability testing is necessary to evaluate the efficacy and user experience of the app, it can be a significant investment of time and resources. Conclusion: The V-Care platform can be used to investigate the reported symptoms experienced by cancer patients receiving Immune checkpoint inhibitors (ICIs) and to compare them with the results from clinical trials. Furthermore, the project will utilize ePRO tools to collect symptoms from patients and provide insight into whether the reported symptoms are linked to the treatment. Clinical Relevance: V-Care provides a secure, easy-to-use interface for patient-clinician communication and data exchange. Its clinical system stores and manages patient data in a secure environment, while its clinical decision support system helps clinicians make decisions that are more informed, efficient, and cost-effective. This system has the potential to improve patient safety and quality of care, while also helping to reduce healthcare costs.

Depression, anxiety and post-traumatic stress during the 2022 Russo-Ukrainian war, a comparison between populations in Poland, Ukraine, and Taiwan.

Ukraine has been embroiled in an increasing war since February 2022. In addition to Ukrainians, the Russo-Ukraine war has affected Poles due to the refugee crisis and the Taiwanese, who are facing a potential crisis with China. We examined the mental health status and associated factors in Ukraine, Poland, and Taiwan. The data will be used for future reference as the war is still ongoing. From March 8 to April 26, 2022, we conducted an online survey using snowball sampling techniques in Ukraine, Poland, and Taiwan. Depression, anxiety, and stress were measured using the Depression, Anxiety, and Stress (DASS)-21 item scale; post-traumatic stress symptoms by the Impact of Event Scale-Revised (IES-R) and coping strategies by the Coping Orientation to Problems Experienced Inventory (Brief-COPE). We used multivariate linear regression to identify factors significantly associated with DASS-21 and IES-R scores. There were 1626 participants (Poland: 1053; Ukraine: 385; Taiwan: 188) in this study. Ukrainian participants reported significantly higher DASS-21 (p < 0.001) and IES-R (p < 0.01) scores than Poles and Taiwanese. Although Taiwanese participants were not directly involved in the war, their mean IES-R scores (40.37 ± 16.86) were only slightly lower than Ukrainian participants (41.36 ± 14.94). Taiwanese reported significantly higher avoidance scores (1.60 ± 0.47) than the Polish (0.87 ± 0.53) and Ukrainian (0.91 ± 0.5) participants (p < 0.001). More than half of the Taiwanese (54.3%) and Polish (80.3%) participants were distressed by the war scenes in the media. More than half (52.5%) of the Ukrainian participants would not seek psychological help despite a significantly higher prevalence of psychological distress. Multivariate linear regression analyses found that female gender, Ukrainian and Polish citizenship, household size, self-rating health status, past psychiatric history, and avoidance coping were significantly associated with higher DASS-21 and IES-R scores after adjustment of other variables (p < 0.05). We have identified mental health sequelae in Ukrainian, Poles, and Taiwanese with the ongoing Russo-Ukraine war. Risk factors associated with developing depression, anxiety, stress, and post-traumatic stress symptoms include female gender, self-rating health status, past psychiatric history, and avoidance coping. Early resolution of the conflict, online mental health interventions, delivery of psychotropic medications, and distraction techniques may help to improve the mental health of people who stay inside and outside Ukraine.

The effectiveness of psychoeducational interventions on caregiver-oriented outcomes in caregivers of adult cancer patients: A systematic review and meta-analysis.

OBJECTIVE: Cancer caregiving can result in increased psychosocial distress and poor health-related quality of life (QOL). Psychoeducation has been shown to be effective in enhancing caregiving-oriented outcomes. A systematic assessment of the overall effect of psychoeducational intervention (PEI) and identification of individual intervention characteristics that may contribute to the effectiveness of PEI is needed. METHODS: For this meta-analysis, relevant articles were identified through electronic databases using key search terms and their medical subject heading such as "family caregiver," "cancer," and "psychoeducational intervention." RESULTS: Twenty-eight controlled trials with 3876 participants were included. PEIs had beneficial effect on depression (Standardized Mean Difference [SMD] -0.26; 95% CI = -0.50 to -0.01, p < 0.04), anxiety (SMD -0.41; 95% CI = -0.82 to 0.01, p < 0.05), caregiver burden (SMD -0.84; 95% CI = -1.22 to -0.46, p < 0.0001) and QOL (SMD 0.59, 95% CI 0.24-0.93; p < 0.0009) at the immediate post-intervention period. At longer-term follow-up, the effectiveness of PEI was maintained on QOL (SMD 0.39, 95% CI = -0.00 to -0.77, p < 0.05), and anxiety (SMD -0.57; 95% CI = -1.09 to -0.06, p < 0.03). Moderation analysis showed that intervention characteristics such as studies conducted in high-income countries, group intervention and studies that focused on specific and mixed cancers explain some of the high variations observed among the included studies. CONCLUSIONS: PEI may benefit caregivers of cancer patients through the significant effects on caregiver burden, QOL, anxiety, and depression. The findings from the moderation analysis may be important for the design of future interventions.

A virtual peer mentoring intervention for baccalaureate nursing students: A mixed-methods study.

BACKGROUND: Final-year baccalaureate nursing students can experience a significant amount of stress that negatively impacts their well-being, academic performance, and transition to professional practice. PURPOSE: This pilot study aimed to evaluate the impact of a Virtual Peer Mentoring (VPM) program using alumni mentors in addressing mental well-being, self-compassion, and professional development needs of final-year baccalaureate nursing students. METHODS: An explanatory sequential mixed-methods design was employed. The quantitative research used a quasi-experimental pretest-posttest design and quantitative data was collected using three validated instruments to assess mental well-being and self-compassion. The qualitative research used an individual and focus group interview design. Twenty-three mentees and eight mentors participated in the VPM program during the 2018-2019 academic year. RESULTS: Quantitative results showed that while mental well-being and self-compassion scores improved post-intervention, the change was not statistically significant. Qualitative analysis uncovered new insights into the participants' experiences and revealed three categories: (1) Continuation of the Mentoring Relationship; (2) Growth as a Recipient of Mentorship; and (3) Continual Development by Being a Mentor. The categories illustrate how mentees perceived benefits to their professional socialization, academic expectations, and well-being while mentors similarly expressed enrichment with their personal growth and professional development as a result of VPM. CONCLUSION: VPM was well-received by participants and show promise in supporting nursing students to manage academic, practice, and socialization challenges. Both mentors and mentees described gaining mutual benefits and professional and personal growth.

Modulation of microbial community dynamics by spatial partitioning.

Microbial communities inhabit spatial architectures that divide a global environment into isolated or semi-isolated local environments, which leads to the partitioning of a microbial community into a collection of local communities. Despite its ubiquity and great interest in related processes, how and to what extent spatial partitioning affects the structures and dynamics of microbial communities are poorly understood. Using modeling and quantitative experiments with simple and complex microbial communities, we demonstrate that spatial partitioning modulates the community dynamics by altering the local interaction types and global interaction strength. Partitioning promotes the persistence of populations with negative interactions but suppresses those with positive interactions. For a community consisting of populations with both positive and negative interactions, an intermediate level of partitioning maximizes the overall diversity of the community. Our results reveal a general mechanism underlying the maintenance of microbial diversity and have implications for natural and engineered communities.

The associations between lifestyle factors and mental well-being in baccalaureate nursing students: An observational study.

Lifestyle factors are modifiable habits that shape the way in which individuals live their lives and can influence mental health. This study examined the associations between lifestyle factors and mental well-being among baccalaureate nursing students at one Canadian university. A cross-sectional, observational online survey was distributed at one urban university campus in Ontario, Canada. Baccalaureate nursing students (n = 147) completed the survey containing questions for demographic variables, sleep quality, dietary pattern, alcohol use, physical activity, sitting time, cigarette smoking, depression, anxiety and stress. Linear regression analysis revealed that more sitting time, poor sleep quality, and low dairy consumption were associated with higher scores in depression, anxiety, and psychological stress. In conclusion, poor lifestyle behaviors such as sedentary lifestyle, poor sleep, and low dairy consumption may reduce the mental well-being of baccalaureate nursing students. Future efforts should aim to establish a causal relationship between lifestyle and mental well-being, which would contribute to the development of lifestyle interventions to promote mental health.

Exploring nursing engagement in providing virtual care to cancer patients in Canada.

As the world struggled with the COVID-19 pandemic, the provision of cancer care, along with all health services, moved more intentionally toward using virtual strategies. The implementation of virtual care had to happen quickly in an effort to provide safe care for individuals and avoid prolonged delays in patient care. Since then, the practice of virtual care and the involvement of oncology nurses in its delivery has evolved. However, there remains little evidence to guide oncology nurses in virtual care and establish best practices. A virtual workshop was held as part of the 2021 Annual Conference of the Canadian Association of Nurses in Oncology to explore the types of involvement oncology nurses have with virtual care, the barriers and facilitators of virtual care, and suggestions for the design of practice standards to guide oncology nurses in this arena of practice. This paper reports the findings of the workshop and shared implications for future priorities.

Cultural contexts during a pandemic: a qualitative description of cultural factors that shape protective behaviours in the Chinese-Canadian community.

BACKGROUND: During the COVID-19 pandemic, there have been significant variations in the level of adoption of public health recommendations across international jurisdictions and between cultural groups. Such variations have contributed to the dissimilar levels of risks associated with this world-changing viral infection and have highlighted the potential role of culture in assigning meaning and importance to personal protective behaviours. The purpose of this study is to describe the cultural factors during the COVID-19 pandemic that shaped protective health behaviours in the Chinese-Canadian community, one of the largest Chinese diasporas outside of Asia. METHODS: A qualitative descriptive design was employed. Content analysis was used to analyze the data from semi-structured virtual interviews conducted with 83 adult Chinese-Canadian participants residing in a metropolitan area in the Province of Ontario, Canada. FINDINGS: The cultural factors of collectivism, information seeking behaviour, symbolism of masks, and previous experience with severe acute respiratory syndrome (SARS) emerged as themes driving the early adoption of personal protective behaviours within the Chinese-Canadian community during the first wave of COVID-19. These protective behaviours that emerged prior to the first nation-wide lockdown in Canada included physical distancing, mask use, and self-quarantine beyond what was required at the time. CONCLUSION: These findings have implications for the development of future public health interventions and campaigns targeting personal protective behaviours in this population and other ethnic minority populations with similar characteristics.

The association among cancer patients' collaboration with their healthcare providers, self-management and well-being during radiotherapy: An observational, cross-sectional survey.

OBJECTIVES: Patients adapt to cancer through self-management, which requires collaboration between patients and their healthcare providers. We aimed to describe patterns of patient-provider collaboration during radiotherapy and examine associations among patient-provider collaboration, self-management and well-being. METHODS: An observational, cross-sectional study was conducted at a cancer centre in the province of Ontario, Canada. Cancer patients (N = 130) completed a one-time questionnaire during their radiotherapy. The questionnaire assessed three variables: collaboration with healthcare providers, self-management and well-being. Patterns of collaboration were analysed using descriptive statistics. Associations among study variables were assessed through structural equation modelling (SEM). Separate models were tested for patient-nurse and patient-oncologist collaboration. RESULTS: Participants reported greater collaboration with oncologists than with nurses or radiation therapists. Most participants reported no collaboration with other providers within healthcare teams (e.g. social workers, dietitians). SEM revealed different patterns for the patient-nurse and patient-oncologist collaboration models, where collaboration predicted one self-management aspect, and both physical and mental well-being. CONCLUSION: During radiotherapy, patients collaborated mainly with doctors, nurses and radiation therapists. Collaborative relationships between patients and providers may enhance patient outcomes by fostering their self-management skills. Initiatives to strengthen patient-provider relationships and support self-management should be developed and applied to interprofessional-cancer-care teams. IMPACT: This is the first known study to empirically support the links among patient-provider collaboration, self-management and patient outcomes. The study results can enhance practice, research and education.

Disturbances Can Promote and Hinder Coexistence of Competitors in Ongoing Partner Choice Mutualisms.

Ecosystems are under threat from anthropogenic and natural disturbances, yet little is known about how these disturbances alter mutualistic interactions. Many mutualistic interactions are highly context dependent and dynamic due to "ongoing" partner choice, impeding our understanding of how disturbances might influence mutualistic systems. Previously we showed that in the absence of additional known mechanisms of competitive coexistence, mutualistic fungi can coexist in a system where the plant community associates dynamically with two empirically defined arbuscular mycorrhizal fungal types: a cheap kind that provides low nutrient benefits, and an expensive type that provides high nutrient benefits. We built on this framework to ask how disturbances of different types, frequencies, amplitudes, and predictabilities alter ongoing partner choice and thereby influence the coexistence of mutualists. We found that the effects of disturbances depend on the type, amplitude, and predictability of disturbances and, to a lesser extent, on their frequency. Disturbance can disrupt mutualist coexistence by enabling hosts more efficiently to exclude partners that behave as parasites. Disturbance can also promote coexistence by altering the strength and direction of consumer-resource interactions. Predicting the effects of disturbance on the mutualist community therefore requires us to understand better the consumer-resource relationships under various environmental conditions. We show how, through such context-dependent effects, disturbance and ongoing partner choice can together generate relative nonlinearity and investment in future benefit, introducing fluctuation-dependent mechanisms of competitive coexistence. Our findings support a broadening of the conceptual framework regarding disturbances and competition to include fluctuation-dependent mechanisms alongside the spatiotemporal intermediate disturbance hypothesis.

Degrés de collaboration perçus entre les patients atteints de cancer et leurs prestataires de soins pendant la radiothérapie.

Cette étude décrit les tendances en matière de relations collaboratives entre les patients et les professionnels de la santé pendant la radiothérapie. Pour ce faire, 130 patients atteints de cancer et traités par radiothérapie dans un centre de cancérologie de l'Ontario ont répondu à un sondage ponctuel. Les principales variables de l'étude portaient sur la collaboration entre les patients et les prestataires de soins de santé et le bien-être des participants. L'étude a révélé que les patients collaboreraient mieux avec les infirmières, les radio-oncologues et les radiothérapeutes qu'avec les nutritionnistes, les travailleurs sociaux et le personnel d'accompagnement spirituel [F(5, 760) = 430,42, p<001]. Les participants qui vivaient davantage de détresse vis-à-vis leurs symptômes collaboraient toutefois mieux les travailleurs sociaux (p < .05) et les nutritionnistes (p < .05), par rapport à ceux qui vivaient moins de détresse. Nous avons émis l'hypothèse selon laquelle les participants dont les symptômes étaient moins contraignants ne ressentaient pas le besoin de rencontrer ces professionnels. Nous discutons actuellement des futures orientations concernant l'intégration de mesures centrées sur le patient (avec l'éducation axée sur l'autogestion, par exemple) dans les modèles interprofessionnels de soins du cancer.

Perceived levels of collaboration between cancer patients and their providers during radiation therapy.

This study described the patterns within collaborative relationships between patients and health care professionals during radiation therapy (RT). A one-time survey was administered to cancer patients (N=130) receiving RT at one Ontario cancer centre. The key study variables were collaboration between patients and health care providers and participants' well-being. Participants reported higher levels of collaboration with nurses, radiation oncologists, and radiation therapists than with dietitians, social workers and spiritual support personnel [F(5, 760) = 430.42, p < .001]. Participants with more symptom distress collaborated more with some health care professionals than those with less distress, but this was only true for collaboration with social workers (p < .05) and dietitians (p < .05). We postulated that participants did not require services from dietitians and social workers when symptom burden was low. Future directions regarding integration of patient-centred measures (e.g., self-management education) into interprofessional models for cancer care are discussed.

Validation par entretien cognitif de l'outil d'évaluation des plaies malignes MWAT-R.

La détresse physique et émotionnelle que peuvent causer au patient et à sa famille les plaies malignes dues à un cancer est souvent négligée. Malheureusement, nous ne disposons pas d'outils de dépistage et d'évaluation fiables et valides pouvant aider à mieux traiter ces plaies. Cette étude a cherché à valider un outil de mesure des résultats rapportés par les patients : le Malignant Wound Assessment Tool - Research (MWAT-R). Pour ce faire, huit patients ont été recrutés et interrogés selon la méthodologie de l'entretien cognitif. La compréhension et l'impression générale des patients vis-à-vis de cet outil ont été analysées. Nous avons constaté que la formulation et les choix de réponse posaient problème aux patients. En général, les participants ont néanmoins trouvé que les questions saisissaient bien les principaux enjeux relatifs aux plaies malignes et tenaient compte du point de vue du patient. Le fait d'établir la validité apparente et de contenu du MWAT-R du point de vue des patients par la technique d'entretien cognitif vient étayer la validité de cet outil.

Validation of the Malignant Wound Assessment Tool - Research (MWAT-R) using cognitive interviewing.

Malignant wounds as a result of cancer are under-recognized for the physical and emotional distress they cause patients and their families. Unfortunately, there is a lack of valid and reliable screening and assessment tools to aid in the management of malignant wounds. This study aims to validate a patient-reported outcome measurement tool, Malignant Wound Assessment Tool - Research (MWAT-R). Eight patients were recruited and interviewed using the cognitive interviewing methodology to validate this tool. Patients' understanding and overall impression of the MWAT-R were explored. Our findings showed that the wording and response options posed challenges for patients in completing the tool. Overall, participants felt that questions captured the key issues related to dealing with a malignant wound and accounted for the patients' perspective. Establishing the content and face validity of the MWAT-R from the patients' perspectives using cognitive interviews has provided further evidence to the validity of this tool.

Undergraduate nursing students' experiences of anxiety-producing situations in clinical practicums: A descriptive survey study.

BACKGROUND: Clinical practicums are regarded as one of the most anxiety-producing aspects of the curriculum by nursing students. Practicum-associated anxiety has negative impacts on learning, performance, and well-being. Little is known about what makes final year nursing students anxious during their practicum experience and the impact of clinical and student characteristics on their level of anxiety. OBJECTIVES: The objectives of the study were (1) to explore which clinical situations final year nursing students perceive as anxiety-producing; (2) to identify if perceived level of anxiety associated with clinical tasks differ by clinical and student characteristics; and (3) to determine the relationship between clinical and student characteristics and perceived level of anxiety among nursing students. DESIGN: Descriptive, cross-sectional survey. SETTING: One university in Ontario, Canada. PARTICIPANTS: A convenience sample of 93 final year undergraduate nursing students. METHODS: The Clinical Experience Anxiety Form (CEAF) was administered to assess perceived level of anxiety associated with common practicum tasks. Descriptive statistics, one-way analysis of variance, and Pearson's correlation tests were used to address the research questions. Content analysis was conducted for open-ended questions. RESULTS: Participants reported the following three situations as most anxiety-producing: fear of making mistakes, being observed by instructors, and initial clinical experience on a unit. Differences were noted between younger (18 to 24 years-old) and older (25 to 34 years-old) students, with the older student group reporting lower levels of anxiety associated with the following clinical situations: being observed by instructors and asking questions of faculty. Age was also found to be negatively correlated with CEAF scores wherein younger students reported higher CEAF scores. Content analysis indicated common areas that worried participants most about their practicum and their academic year. CONCLUSIONS: Findings emphasize the importance of nursing educators to recognize anxiety-producing practicum situations and develop anxiety management interventions to ensure optimal learning.

A unifying framework for interpreting and predicting mutualistic systems.

Coarse-grained rules are widely used in chemistry, physics and engineering. In biology, however, such rules are less common and under-appreciated. This gap can be attributed to the difficulty in establishing general rules to encompass the immense diversity and complexity of biological systems. Furthermore, even when a rule is established, it is often challenging to map it to mechanistic details and to quantify these details. Here we report a framework that addresses these challenges for mutualistic systems. We first deduce a general rule that predicts the various outcomes of mutualistic systems, including coexistence and productivity. We further develop a standardized machine-learning-based calibration procedure to use the rule without the need to fully elucidate or characterize their mechanistic underpinnings. Our approach consistently provides explanatory and predictive power with various simulated and experimental mutualistic systems. Our strategy can pave the way for establishing and implementing other simple rules for biological systems.

Dynamic preferential allocation to arbuscular mycorrhizal fungi explains fungal succession and coexistence.

Evidence accumulates about the role of arbuscular mycorrhizal (AM) fungi in shaping plant communities, but little is known about the factors determining the biomass and coexistence of several types of AM fungi in a plant community. Here, using a consumer-resource framework that treats the relationship between plants and fungi as simultaneous, reciprocal exploitation, we investigated what patterns of dynamic preferential plant carbon allocation to empirically-defined fungal types (on-going partner choice) would be optimal for plants, and how these patterns depend on successional dynamics. We found that ruderal AM fungi can dominate under low steady-state nutrient availability, and competitor AM fungi can dominate at higher steady-state nutrient availability; these are conditions characteristic of early and late succession, respectively. We also found that dynamic preferential allocation alone can maintain a diversity of mutualists, suggesting that on-going partner choice is a new coexistence mechanism for mutualists. Our model can therefore explain both mutualist coexistence and successional strategy, providing a powerful tool to derive testable predictions.

Elasticity of population growth with respect to the intensity of biotic or abiotic driving factors.

Demographic analysis can elucidate how driving factors, such as climate or species interactions, affect populations. One important question is how growth would respond to future changes in the mean intensity of a driving factor or in its variability, such as might be expected in a fluctuating and shifting climate. Here I develop an approach to computing new stochastic elasticities to address this question. The linchpin of this novel approach is the multidimensional demographic difference that expresses how a population responds to change in the driving factor between two discrete levels of intensity. I use this difference to design a perturbation matrix that links data from common empirical sampling schemes with rigorous theory for stochastic elasticities. Although the starting point is a difference, the products of this synthesis are true derivatives: they are elasticity with respect to the mean intensity of a driving factor, and elasticity with respect to variability in a driving factor. Applying the methods to published data, I demonstrate how these new elasticities can shed light on growth rate response within and at the boundary of the previously observed range of the driving factor, thus helpfully indicating nonlinearity in the observed and in the potential future response. The stochastic approach simplifies in a fixed environment, yielding a compact formula for deterministic elasticity to a driving factor.