The phenomenology of attentional control: a first-person approach to contemplative science and the issue of free will.

There are two basic aspects of attentional control. The ability to direct attention toward different objects is typically experienced as a fundamental indicator of attentional freedom. One can control what one attends to and directing attention is a relatively simple task. In contrast, sustaining attention on a chosen object proves to be difficult as mind-wandering seems to be inevitable. Does the problem of sustaining attention, mean that we are fundamentally unfree? We discuss this issue in light of an introspective study of directing and sustaining attention, looking specifically into the question of whether it is possible to experience the source of attention, i.e., the subject enacting freedom through attention. The study involved six persons performing different attention tasks over the course of about a month. Common experiences and contrasting reports are presented. This forms the basis for a discussion of the method of introspection and in particular of how to approach conflicting reports.

Psychological precursors of epileptic seizures.

Psychological stress is the most commonly self-reported precursor of epileptic seizures. However, retrospective and prospective studies remain inconclusive in this regard. Here, we explored whether seizures would be preceded by significant changes in reported stressors or resource utilization. This study is based on high-frequency time series through daily online completion of personalized questionnaires of 9-24 items in epilepsy outpatients and compared responses 1-14 days before seizures with interictal time series. Fourteen patients (79% women, age = 23-64 years) completed daily questionnaires over a period of 87-898 days (median = 277 days = 9.2 months). A total of 4560 fully completed daily questionnaires were analyzed, 685 of which included reported seizure events. Statistically significant changes in preictal compared to interictal dynamics were found in 11 of 14 patients (79%) across 41 items (22% of all 187 items). In seven of 14 patients (50%), seizures were preceded by a significant mean increase of stressors and/or a significant mean decrease of resource utilization. This exploratory analysis of long-term prospective individual patient data on specific stressors and personal coping strategies generates the hypothesis that medium-term changes in psychological well-being may precede the occurrence of epileptic seizures in some patients.

Pressure Time Dose as a Representation of Intracranial Pressure Burden and Its Dependency on Intracranial Pressure Waveform Morphology at Different Time Intervals.

Intracranial pressure (ICP) burden or pressure time dose (PTD) is a valuable clinical indicator for pending intracranial hypertension, mostly based on threshold exceedance. Pulse frequency and waveform morphology (WFM) of the ICP signal contribute to PTD. The temporal resolution of the ICP signal has a great influence on PTD calculation but has not been systematically studied yet. Hence, the temporal resolution of the ICP signal on PTD calculation is investigated. We retrospectively analysed continuous 48 h ICP recordings with high temporal resolution obtained from 94 patients at the intensive care unit who underwent neurosurgery due to an intracranial haemorrhage and received an intracranial pressure probe (43 females, median age: 72 years, range: 23 to 88 years). The cumulative area under the curve above the threshold of 20 mmHg was compared for different temporal resolutions of the ICP signal (beat-to-beat, 1 s, 300 s, 1800 s, 3600 s). Events with prolonged ICP elevation were compared to those with few isolated threshold exceedances. PTD increased for lower temporal resolutions independent of WFM and frequency of threshold exceedance. PTDbeat-to-beat best reflected the impact of frequency of threshold exceedance and WFM. Events that could be distinguished in PTDbeat-to-beat became magnified more than 7-fold in PTD1s and more than 104 times in PTD1h, indicating an overestimation of PTD. PTD calculation should be standardised, and beat-by-beat PTD could serve as an easy-to-grasp indicator for the impact of frequency and WFM of ICP elevations on ICP burden.

Patient satisfaction in inpatient psychiatric treatment compared with inpatient equivalent home treatment in Germany: an in-depth qualitative study.

Background: Inpatient treatment (IT) is the predominant form of psychiatric care in Germany and worldwide, whereby forms of psychiatric treatment have mainly evolved in the direction of home services. Inpatient equivalent home treatment (IEHT) is a new and additional pillar of psychiatric acute care provision legally embedded since 2018 in Germany. Objective: The aim of this study was to conduct an in-depth exploration as little qualitative research has been performed so far in Germany to examine possible differences in patient satisfaction with IT compared with IEHT. Methods: In the current qualitative study, N = 9 patients of a German hospital providing IT and IEHT were interviewed with the problem-centered interview. Inclusion criteria were IT or IT with subsequent IEHT. The theoretical sampling method was applied to select test persons in the research process. The experiences of the participants during their psychiatric treatment were analyzed using a qualitative content analysis. Results: The results of both types of psychiatric treatment refer to different satisfaction factors during the treatment period. The function of fellow patients, the setting of the treatment, the conditions in place, and the relationship to relatives turn out to be pivotal for patient satisfaction. In addition, the quality of the therapy and relationship to caregivers itself can have an impact on patient satisfaction, particularly by shared decision making. During the IEHT, patient satisfaction can be strengthened by the possibility to handle daily tasks, to be close to relatives, while not so close to fellow patients, whereas IT patients are mostly satisfied because of the distance to their everyday life and the closeness to fellow patients. The choice of the form of psychiatric treatment according to the individual needs of the patients seems to be one key driver that can in turn increase patient satisfaction. In addition, a clean and hygienic environment seems to be critical for our respondents as a lack of it is one of the reasons to drop out of treatment. Conclusions: Despite its limitations, this hypothesis-generating study is one of the first investigating German IEHT in comparison with IT in an in-depth qualitative approach contributing to a patient-oriented and cost-effective psychiatric treatment. Although hospitals are highly complex organizations and therefore not directly comparable, other German and international providers of IEHT may derive several generic success factors from this study for the development and improvement of patient satisfaction.

Training naive subjects in using micro-phenomenological self-inquiry to investigate pain and suffering during headaches.

Micro-phenomenology is a method that generates rich and reliable reports of singular experiences in their pre-reflective dimension. Usually it is employed using a second-person interviewer. In this study we attempted to train naïve subjects in using self-inquiry version of the method. 13 subjects met twice over the course of one week, investigating their experiences of headaches, looking specifically into the pain experience itself, the experience of suffering, and the experience of absence of suffering. The analysis showed that the subject reports increase the richness of description, measured by the increase in the amount of categories described and the number of words needed to give an on target description. The analysis, informed by the participant's ideas, showed that it was possible to distinguish the experience of pain from the experience of suffering. We compare the analysis to other phenomenological studies of headaches. This reveals the strength and weakness of the micro-phenomenological method: By de-focusing on contextual factors it enables in-depth descriptions of singular moments of experience, but the bracketing of interpretations may result in overlooking overarching meaning dimensions. We conclude that micro-phenomenological self-inquiry may potentially be employed successfully in a clinical setting with initially untrained subjects for describing certain kinds of experiences and answering complex phenomenological questions.

Why context matters when changing the diet: A narrative review of placebo, nocebo, and psychosocial context effects and implications for outcome research and nutrition counselling.

Placebo (PE) and nocebo effects (NE) have been subjects of systematic research in medicine and psychotherapy for many decades to distinguish between the (specific) pharmacological effect of medication and the (unspecific) effect of the context. Despite this significant research, the awareness, operationalisation, and reflection of the multiplicity of PE, NE, and psychosocial context effects (PSCE) is currently limited when researching outcomes of diet changes in studies without randomisation and placebo control. This neglection is critical as it could systematically influence outcomes by moderating and mediating them and thus reducing the validity and evidence base of these studies. Therefore, we performed a (non-systematic) narrative review (NR) on the following objectives: (1) present a concise overview about the relevance of PE, NE, and PSCE in medicine and nutrition research; (2) review the current state of research on reflecting context effects when studying diet changes; (3) provide useful theoretical foundations via consideration and integration of micro- and macro context effects; (4) operationalise as hypotheses the potential PE, NE, and PSCE which are specific for researching diet changes; and (5) derive their impact for future research as well as for nutrition counselling. The electronic search in this NR for objective (2) identified N = 5 publications and for objective (4) we found N = 61 articles retrieved in the first round of search, additional references were identified by a manual and snowball search among the cited references resulting finally in N = 37. This NR offers a synoptical basis to foster awareness and operationalisation of a variety of PE, NE, and PSCE. Interdisciplinary research teams should monitor these factors using, e.g., qualitative, mixed-method studies, process evaluation, item bank approaches, moderator and mediator analysis that might reveal substantially new insights, and outcomes of relevance to science and nutrition counselling. Nevertheless, the present NR has several limitations, especially as it is non-systematic, because it is a very heterogeneous field of research, in which the topic we are investigating is usually regarded as marginal and subordinate. Therefore, future research should conduct systematic reviews and particularly theory-based primary studies (experimental research) on hypotheses of PE, NE, and PSCE in outcome research in diet changes.

Personalized high-frequency monitoring of a process-oriented psychotherapeutic approach to seizure disorders: Treatment utilization and participants' feedback.

High-frequency monitoring of psychological variables has been recommended to monitor and manage psychotherapeutic processes. However, high-frequency monitoring might be regarded as burdensome for participating patients. This feasibility study applied the concept of high-frequency treatment monitoring in patients with seizures and psychiatric comorbidities in an outpatient neurology service. The treatment monitoring entailed the development of a personalized process questionnaire, daily online monitoring, and regular reflection of the current time series graphs. Participants' feedback on user-friendliness and usefulness of this treatment monitoring was evaluated quantitatively and qualitatively. Participants' compliance rates (CRs) of daily self-assessments after 6 months were correlated with their quantitative feedback on user-friendliness and usefulness and the number of scheduled treatment sessions during this time period. Twenty patients, 15 women/5 men, median age 48 years (range: 23-73 years), were recruited. The median number of scheduled sessions was 11 sessions (range: 6-22). Participants reported a high overall satisfaction with the user-friendliness and usefulness of treatment monitoring. No notable correlations could be found between CRs and quantitative feedback nor between CRs and the number of scheduled treatment sessions. Personalized high-frequency monitoring of psychological variables seems to be feasible to monitor and manage process-oriented psychotherapeutic care in patients with seizures and psychiatric comorbidities. The results support the user-friendliness and usefulness of high-frequency monitoring and suggest that high-frequency monitoring may be suitable for monitoring of low-frequent treatment sessions and patients with attendance issues. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Process-oriented and personalized psychotherapeutic care for epilepsy: Interim results of a feasibility study.

BACKGROUND: There is great scientific and clinical interest in the effective integration of psychological treatments into comprehensive epilepsy care to optimize treatment outcomes and psychosocial functioning in people with epilepsy. Stepped care is a promising approach to accommodate personalized psychotherapeutic care in academic and regular outpatient settings. It aims at providing patients with the most adequate treatment duration, number of sessions, and treatment method while systematically monitoring their treatment processes. METHODS: This is an uncontrolled feasibility study of process-oriented and personalized psychotherapeutic care for epilepsy in a naturalistic setting. The objective of this study was to evaluate individual changes of health-related quality of life (QOLIE-31) and psychiatric comorbidity (BDI-II, BSI) in participants by applying the concept of the reliable change index (RCI) to outcomes that were obtained at baseline and six months after the beginning of the intervention. Additionally, we assessed the relationship between outcome scores, the number of attended sessions, and history of childhood trauma by linear regression models. RESULTS: Twenty patients [15 women/5 men, median age 48 years (range: 23-73 years)] were recruited. The median number of scheduled sessions was 11 (range: 6-22); there were no drop-outs. After psychotherapy quality of life (QOLIE-31), global distress (BSI) and depression (BDI-II) scores improved significantly (p-values: QOLIE-31: 0.03; BSI: 0.01; BDI-II: 0.01). The largest improvements were achieved for the emotional well-being subscale of the QOLIE-31 (47%, p-value: 0.02), the global severity index of the BSI (83%), and depression severity (BDI-II) (60%). Linear regression models did not reveal any significant association between interim changes, number of attended treatment sessions, and history of childhood trauma. CONCLUSION: The results suggest that process-oriented and personalized psychotherapeutic has low attrition and results in improved quality of life and reduced psychiatric symptoms in people with epilepsy. Our findings indicate that responsiveness to psychotherapy is not dependent on the number of attended treatment sessions. Participants with childhood trauma did not need more treatment sessions to achieve an improvement. More research is needed to understand and address mechanisms and precursors of responsiveness to psychotherapy.

First-person access to decision-making using micro-phenomenological self-inquiry.

Micro-phenomenology is a method for improving first-person reports of experience. Usually, micro-phenomenology is conducted using a second-person interviewer who guides someone investigating an experience. This has the advantage that the interviews can be done with untrained subjects. However, it is possible to perform micro-phenomenological self-inquiry, a form of self-interview technique, without a second-person interviewer. This has several advantages, such as being more time and cost effective. Questionable, however, is the possibility for untrained subjects to enquire into their own experience using micro-phenomenology. The present study aims to test the reliability of micro-phenomenological self-inquiry with untrained subjects using a guiding document. We replicated an experimental design that has previously been employed to test whether micro-phenomenology increases the reliability of reports. The experiment did not replicate. Reasons for this may be: (1) a methodological weakness of the previous study; (2) that the way the self-inquiry format employed as part of the present study was ineffective; or (3) that micro-phenomenological self-inquiry requires training. These specific possibilities and the idea of testing the reliability of micro-phenomenological reports in general are discussed. We conclude that the self-inquiry format is not sufficient for conducing micro-phenomenological studies and that training is required.

High-frequency monitoring of personalized psychological variables during outpatient psychotherapy in people with seizures: An uncontrolled feasibility study.

BACKGROUND: This feasibility study applied the concept of daily systematic monitoring of personalized psychological variables and investigated patients' compliance in order to evaluate if its integration in outpatient psychotherapy is feasible and if patients found the development and daily application of personalized questionnaires user-friendly and useful. METHODS: A naturalistic sample of patients with epilepsy (PWE) was enrolled to participate in an outpatient psychotherapy program. A personalized process questionnaire was developed with each patient based on an individual psychological system's model at the outset of therapy. Daily time-stamped self-assessments were collected during outpatient psychotherapy. This process-monitoring was technically realized by an internet-based device for data collection and data analysis, the Synergetic Navigation System (SNS). The reflection of person-specific time series informed by patients' replies to their personalized process questionnaire was integrated in the therapy process. Compliance rates were assessed during a period of six months (i.e., 180 days) after the first entry of the questionnaire [compliance rate = (number of completed questionnaires/180) × 100]. User-friendliness and usefulness of this process monitoring were evaluated quantitatively. RESULTS: Twenty patients [15 women/5 men, median age 48 years (range 23-73 years)] were recruited. Compliance rates were high (median: 93%, range 31-100%) among the participants. Participants reported a high overall satisfaction with the application and user-friendliness of SNS. CONCLUSION: The results support the feasibility of high-frequency monitoring of personalized psychological processes during outpatient psychotherapy. Repeated daily assessments of a personalized questionnaire yield highly resolved, equidistant time series data, which gives insight into individual psychological processes during outpatient psychotherapy.

Comparison of Two Algorithms Analysing the Intracranial Pressure Curve in Terms of the Accuracy of Their Start-Point Detection and Resistance to Artefacts.

OBJECTIVES: For further insight into the possibly predictive quality of the intracranial pressure (ICP) waveform morphology a definite and reliable identification of its components is a prerequisite but presents the problem of artefacts in physiological signals. METHODS: ICP and electrocardiogram (ECG) data were recorded to depict not only their numerical value but also their respective waveforms and were analysed by two algorithms, which were then compared for their artefact resistance.The algorithms in question identify the start point of every ICP wave, one (AR[SA]) by scale analysis, the other (AR[ECG]) by analysing the ICP wave linked to the ECG. RESULTS: Start-point identification accuracy in rhythmic patients showed sensitivity of 95.14% for AR[SA] and 99.99% for AR[ECG], with a positive predictive value (ppv) of 98.30% for AR[SA] and 99.76% for AR[ECG].In arrhythmic patients sensitivity was 98.05% for AR[SA] and 99.73% for AR[ECG], with a ppv of 100% for AR[SA] and 99.78% for AR[ECG]. CONCLUSIONS: AR[ECG] has proven to be more resistant to artefacts than AR[SA], even in cases such as cardiac arrhythmia. It facilitates reliable, three-dimensional visualisation of long-term changes in ICP-wave morphology and is thus suited for analysis in cases of more complex or irregular vital parameters.

Empathy, well-being and stressful experiences in the clinical learning environment.

OBJECTIVE: This study examines whether students in the clinical phase show reduced well-being and lower empathy scores compared to preclinical students. Furthermore, it explores students' most stressful experiences. METHODS: A cross-sectional mixed-methods study was conducted among medical students of the revised patient- and student-centred curriculum at Witten/Herdecke University (Germany). An online survey included questions regarding empathy (JSPE-S), well-being (WHO-5), distressing factors in the learning and clinical environments, mistreatment and thoughts of dropping out. RESULTS: 176 (34 %) of 517 medical students completed the questionnaire, 73 being preclinical and 103 clinical students. Despite lower well-being, clinical student did not demonstrate lower empathy levels. Main stressors during the clinical phase were negative physician role models and financially focussed care rather than challenging patient encounters. Compared to preclinical students, clinical students showed more mistreatment experiences and higher ratings towards thoughts of dropping out. CONCLUSION: Our results illustrate contemporary challenges to establishing a learner-centred clinical environment that nurtures well-being and empathy of medical students. The sustainment of empathy despite more stressful experiences and lower well-being may be due to protective factors. PRACTICE IMPLICATIONS: The paper suggests activities to support clinical students to find ways to adapt the clinical learning environment to students' needs.

History and development of medical studies at the University of Witten/Herdecke - an example of "continuous reform".

Introduction: The University of Witten/Herdecke (UW/H) was founded in 1982 as the first privately run German university. In addition to economics, dentistry, a center for life sciences and the institute for general studies, the main focus from the inception of the University was the development of a model course in medical studies. Methodology: A description of the history of the development of medical studies in relation to the reasons for its founding, its founding ideals and their implementation; phases of development, transformations and influencing factors are presented in detail. External assessments are also used for this purpose. Result: The "Herdecke Model" was first implemented with the initial group of medical students in 1983. In the past 36 years the curriculum for medical education in Witten/Herdecke has evolved to meet internal and external requirements. The goals of the founders for a reform of medical studies and the founding ideals of the UW/H have continued to lead the University through a continuous reform process of medical training. From the first model of a reform degree course at UW/H 1983 to the current Model Study Course/Modellstudiengang (MSG 2018plus), these reforms have manifested themselves in four major phases spanning a 15 year period. Landmarks of the reforms include the first systematic introduction of problem-oriented learning in Germany, and clinical and practical training with real patients in both clinical and general medical elective blocks that far surpass the Medical Licensure Act's requirements. Additionally noteworthy are the introduction of PY training wards and the active participation and co-design role students may hold. Discussion: Due to the small size of UW/H, reforms can be tested quickly and implemented with ease and flexibility. This facilitates a "laboratory setting" for the testing of future-oriented innovations. The small size has allowed various concepts to be able to be used as models, thus serving as stimuli for larger change in medical studies in Germany.

The True Self. Critique, Nature, and Method.

The history of philosophy gives us many different accounts of a true self, connecting it to the essence of what a person is, the notion of conscience, and the ideal human being. Some proponents of the true self can also be found within psychology, but its existence is mostly rejected. Many psychological studies, however, have shown that people commonly believe in the existence of a true self. Although folk psychology often includes a belief in a true self, its existence is disputed by psychological science. Here, we consider the critique raised by Strohminger et al., stating that the true self is (1) radically subjective and (2) not observable, hence cannot be studied scientifically (Strohminger et al., 2017). Upon closer investigation, the argument that the self is radically subjective is not convincing. Furthermore, rather than accepting that the true self cannot be studied scientifically, we ask: What would a science have to look like to be able to study the true self? In order to answer this question, we outline the conceptual nature of the true self, which involves phenomenological and narrative aspects in addition to psychological dimensions. These aspects together suggest a method through which this concept can be investigated from the first-person perspective. On a whole, we propose an integrative approach to understanding and investigating the true self.

On the relevance of symbolizing heart rate variability by means of a percentile-based coarse graining approach.

OBJECTIVE: Symbolic transformations of the cardiac interbeat interval series yield a coarse-grained description of the dynamical information of the underlying system and complement standard measures of heart rate variability. The most commonly utilized coarse graining procedures are strongly influenced by the presence of a few extreme values wasting precious symbols to code very unlikely values. APPROACH: Here, we used a transformation procedure that ensured the appearance of each symbol with equal probability using a short alphabet, A 4 = {0, 1, 2, 3}, and a long alphabet, A 6 = {0, 1, 2, 3, 4, 5}. The procedure was applied to the cardiac interbeat interval series of 17 healthy subjects, obtained during graded head-up tilt tests at tilt table inclinations of 0°, 15°, 30°, 45°, 60°, 75°, 90°. The dynamics of the symbolic series was assessed by the rate of symbolic pattern categories. Symbolic patterns of length three were grouped according to the variations of the symbols in each pattern: no variation (0V%), one variation (1V%), two like variations (2LV%) and two unlike variations (2UV%) of the symbols. MAIN RESULTS: As for the alphabet A 4, the linear regression analysis on tilt angle showed that 0V% increased with increasing tilt angle whereas 1V%, 2LV% and 2UV% decreased. As for the alphabet A 6, the categories 0V%, and 1V% increased with increasing tilt angle whereas 2LV% and 2UV% decreased. SIGNIFICANCE: The symbolic transformation ensuring a uniform distribution of the symbols is capable of reflecting changes in the cardiac autonomic nervous system during graded head-up tilt. This approach is more robust against outliers and data with skewed distributions compared to previously used symbolizations.

Sleep Instabilities Assessed by Cardiopulmonary Coupling Analysis Increase During Childhood and Adolescence.

The electrocardiogram-based cardiopulmonary coupling (CPC) technique may be used to track sleep instabilities. With progressing age, maturational changes during childhood and adolescence affect sleep. The objective was to assess developmental changes in sleep instabilities in a natural setting. ECGs during nighttime sleep on regular school days were recorded from 363 subjects aged 4 to 22 years (204 females). The estimated total sleep time (ETST) decreased from 598 to 445 min during childhood and adolescence. Stable sleep linearly decreased with progressing age (high frequency coupling (HFC): 70-48% ETST). Unstable sleep [low frequency coupling (LFC): 9-19% ETST], sleep fragmentation or disordered breathing (elevated LFC: 4-12% ETST), and wake/REM states [very low frequency coupling (VLFC): 20-32% ETST] linearly increased with age. Hence, with progressing age the sleep of children and adolescents shortens, becomes more unstable and is more often affected by fragmentation or sleep disordered breathing, especially in the age group >13 years. It remains to be clarified whether some of the changes are caused by a social jetlag, i.e., the misalignment of body clock and social time especially in adolescents.

Students with an autonomous role in hospital care - patients perceptions.

BACKGROUND: There have been calls to enhance clinical education by strengthening supported active participation (SAP) of medical students in patient care. This study examines perceived quality of care when final-year medical students are integrated in hospital ward teams with an autonomous relationship toward their patients. METHODS: We established three clinical education wards (CEWs) where final-year medical students were acting as "physician under supervision". A questionnaire-based mixed-method study of discharged patients was completed in 2009-15 using the Picker Inpatient Questionnaire complemented by specific questions on the impact of SAP. Results were compared with matched pairs of the same clinical specialty from the same hospital (CG1) and from nationwide hospitals (CG2). Patients free-text feedback about their hospital stay was qualitatively evaluated. RESULTS: Of 1136 patients surveyed, 528 (46.2%) returned the questionnaire. The CEWs were highly recommended, with good overall quality of care and patient-physician/student-interaction, all being significantly (p < 0.001) higher for the CEW group while experienced medical treatment success was similar. Patient-centeredness of students was appreciated by patients as a support to a deeper understanding of their condition and treatment. CONCLUSION: Our study indicates that SAP of final-year medical students is appreciated by patients with high overall quality of care and patient-centeredness.

Outer and Inner Dimensions of Brain and Consciousness - Refining and Integrating the Phenomenal Layers.

In view of the unresolved mind-brain problem, we examine a number of prototypical research attitudes regarding the question, how the mental and the neuronal realms are related to each other, both functionally and ontologically. By discussing neurophilosophical and neuropsychological positions, the mind-brain problem can be recast in terms of a structural relation between methodological and content-related aspects. Although this reformulation does not immediately lead to a solution, it draws attention to the necessity of searching for a new way of balancing separating and integrating elements regarding content as well as method. As a relatively unknown alternative in this context we investigate an approach by the philosopher Rudolf Steiner. It comprises a firstperson method, along with the theoretical background of what has come to be known as the mirror metaphor - an analogy for the brain as a necessary but not a sufficient basis for mental activity. Through a first-person study, this approach is scrutinized using volitionally controlled perceptual reversals. The results allow for a phenomenological distinction of processual phases which can be summarized as engaging and disengaging forms of mental activity. Finally, we initiate a discussion in view of related philosophical concepts and give an outlook on the next possible research steps.