Phytotoxic Interaction Studies – Techniques for Evaluation and Presentation of Results

Weed Science ◽  
1981 ◽  
Vol 29 (2) ◽  
pp. 147-155 ◽  
Author(s):  
R. G. Nash
Keyword(s):  
Growth Response ◽  
Statistical Significance ◽  
Multiple Regression Equation ◽  
Parameter Method ◽  
Regression Estimate ◽  
Pesticide Concentration ◽  
Response Data ◽  
The Individual ◽  
Multiplicative Models ◽  
Two Parameter

Two or more pesticides together may produce a growth response in plants that is not predictable by their individual or independent toxicities. This unpredicted (dependent) response results from an interaction, a concept that usually is not easily interpreted. Dependent responses are further complicated by the fact that they can be either synergistic or antagonistic. Several methods exist for identifying and measuring phytotoxic interactions. Nearly all methods have certain shortcomings, however. Additive and multiplicative models (mathematical expressions) are the two basic approaches to determining pesticide interactions. The two-parameter, isobole, and calculus methods axe additive; whereas, Colby and regression estimate are multiplicative models. Regression estimate analysis considers deviations due to experimental errors, and a statistical significance can be attached to the interaction magnitude, thereby overcoming the deficiencies of the Colby method, but both methods seem to be limited to response data in which the combined pesticide concentration is the sum of the individual pesticide concentrations. The two-parameter method seems to be limited to response data in which the combined concentration is equal to the individual pesticide concentration and to response data in which a pesticide concentration necessary to produce a 50% of control value is interpolated rather than extrapolated. The calculus method is a mathematical expression of the growth response, and interaction is measured by derivation of the equation obtained. The calculus method is difficult to interpret and has a major weakness because it depends upon the multiple regression equation of the observed data. The regression estimate method is recommended as a reasonable approach to interpretation of interaction type data, with a SAS language computer program available from the author.

The Subjective Present and Its Modulation in Clinical Contexts

2013 ◽  
Vol 1 (2) ◽  
pp. 239-259 ◽  
Author(s):  
Wolfgang Tschacher ◽  
Fabian Ramseyer ◽  
Claudia Bergomi
Keyword(s):  
Perceptual Grouping ◽  
Statistical Significance ◽  
Temporal Distribution ◽  
Future Research ◽  
Implicit Processes ◽  
The Social ◽  
Gestalt Perception ◽  
Psychotherapeutic Techniques ◽  
The Mean ◽  
The Individual

Time is a basic dimension in psychology, underlying behavior and experience. Timing and time perception constitute implicit processes that are often inaccessible to the individual person. Research in this field has shown that timing is involved in many areas of clinical significance. In the projects presented here, we combine timing with seemingly different fields of research, such as psychopathology, perceptual grouping, and embodied cognition. Focusing on the time scale of the subjective present, we report findings from three different clinical studies: (1) We studied perceived causality in schizophrenia patients, finding that perceptual grouping (‘binding’, ‘Gestalt formation’), which leads to visual causality perceptions, did not distinguish between patients and healthy controls. Patients however did integrate context (provided by the temporal distribution of auditory context stimuli) less into perceptions, in significant contrast to controls. This is consistent with reports of higher inaccuracy in schizophrenia patients’ temporal processing. (2) In a project on auditory Gestalt perception we investigated auditory perceptual grouping in schizophrenia patients. The mean dwell time was positively related to how much patients were prone to auditory hallucinations. Dwell times of auditory Gestalts may be regarded as operationalizations of the subjective present; findings thus suggested that patients with hallucinations had a shorter present. (3) The movement correlations of interacting individuals were used to study the non-verbal synchrony between therapist and patient in psychotherapy sessions. We operationalized the duration of an embodied ‘social present’ by the statistical significance of such associations, finding a window of roughly 5.7 seconds in conversing dyads. We discuss that temporal scales of nowness may be modifiable, e.g., by mindfulness. This yields promising goals for future research on timing in the clinical context: psychotherapeutic techniques may alter binding processes, hence the subjective present of individuals, and may affect the social present in therapeutic interactions.

Stability in Waking-Sleep States in Neonates as a Predictor of Long-Term Neurologic Outcome

PEDIATRICS ◽  
1985 ◽  
Vol 76 (1) ◽  
pp. 52-63
Author(s):  
Cesare T. Lombroso ◽  
Yoichi Matsumiya
Keyword(s):  
Statistical Significance ◽  
Observation Time ◽  
Long Term Outcomes ◽  
Newborn Period ◽  
Waking And Sleep ◽  
Total Observation Time ◽  
Total Observation ◽  
The Individual

Thirty-three full-term neonates were ranked blindly on a scale ranging from the least to the highest "risk" for future neurologic complications on the basis of available perinatal biographies, tests, and examinations performed during the newborn period. Four prolonged polygraphic-behavioral recordings were obtained one week apart beginning at ten days after birth. Five waking and sleep states were scored in each session as percentages of total observation time, giving a total of 20 scores for each baby to be subjected to analysis of variance. These measures also provided individual profile consistency or variability in maintaining waking-sleep states over the selected period of postnatal time. The whole cohort, except three infants who could not be followed adequately, was then reexamined periodically over a period ranging from 3 to 4 years (±6 months) for neurologic and developmental assessments. Except for two scores that produced a low level of statistical significance (P < .05), the other 18 scores were found to be not associated with long-term outcomes. Even the first two scores were not satisfactory discriminators for the outcome of the individual babies. However, when coefficients of concordance (W) were computed from each individual baby profile, significant statistics (P < .001) emerged to indicate good correlations between high or low W values in the newborn period and long-term outcomes. All 17 newborns who had W scores greater than 0.9 were found to be normal at follow-up regardless of the poor ranking given several of them during the newborn period. Among the 13 newborns who had W scores less than 0.9, 11 had a poor clinical outcome at follow-up, though several had been ranked initially as falling within the least "risk" group.

scholarly journals Synthesis and Characterization of a Bioartificial Polymeric System with Potential Antibacterial Activity: Chitosan-Polyvinyl Alcohol-Ampicillin

Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3109 ◽  
Author(s):  
Andres Bernal-Ballen ◽  
Jorge Lopez-Garcia ◽  
Martha-Andrea Merchan-Merchan ◽  
Marian Lehocky
Keyword(s):  
Antibacterial Activity ◽  
Polyvinyl Alcohol ◽  
Statistical Significance ◽  
Antibacterial Properties ◽  
Intermolecular Forces ◽  
Polymeric System ◽  
Bacterial Strains ◽  
Natural Polymers ◽  
The Matrix ◽  
The Individual

Bio-artificial polymeric systems are a new class of polymeric constituents based on blends of synthetic and natural polymers, designed with the purpose of producing new materials that exhibit enhanced properties with respect to the individual components. In this frame, a combination of polyvinyl alcohol (PVA) and chitosan, blended with a widely used antibiotic, sodium ampicillin, has been developed showing a moderate behavior in terms of antibacterial properties. Thus, aqueous solutions of PVA at 1 wt.% were mixed with acid solutions of chitosan at 1 wt.%, followed by adding ampicillin ranging from 0.3 to 1.0 wt.% related to the total amount of the polymers. The prepared bio-artificial polymeric system was characterized by FTIR, SEM, DSC, contact angle measurements, antibacterial activity against Staphylococcus aureus and Escherichia coli and antibiotic release studies. The statistical significance of the antibacterial activity was determined using a multifactorial analysis of variance with ρ < 0.05 (ANOVA). The characterization techniques did not show alterations in the ampicillin structure and the interactions with polymers were limited to intermolecular forces. Therefore, the antibiotic was efficiently released from the matrix and its antibacterial activity was preserved. The system disclosed moderate antibacterial activity against bacterial strains without adding a high antibiotic concentration. The findings of this study suggest that the system may be effective against healthcare-associated infections, a promising view in the design of novel antimicrobial biomaterials potentially suitable for tissue engineering applications.

scholarly journals A cross-sectional study of the use and effectiveness of the Individual Development Plan among doctoral students

F1000Research ◽  
2018 ◽  
Vol 7 ◽  
pp. 722 ◽  
Author(s):  
Nathan L. Vanderford ◽  
Teresa M. Evans ◽  
L. Todd Weiss ◽  
Lindsay Bira ◽  
Jazmin Beltran-Gastelum
Keyword(s):  
Career Development ◽  
Doctoral Students ◽  
Online Survey ◽  
Career Planning ◽  
Statistical Significance ◽  
Development Plan ◽  
Individual Development ◽  
Negative Consequences ◽  
Cross Sectional ◽  
The Individual

Background: The Individual Development Plan (IDP) was introduced as a tool to aid in career planning for doctoral trainees. Despite the National Institutes of Health and academic institutions creating policies that mandate the use of IDPs, little information exists regarding the use and effectiveness of the career planning tool. Methods: We conducted a multi-institutional, online survey to measure IDP use and effectiveness. The survey was distributed to potential respondents via social media and direct email. IDP survey questions were formatted using a five-point Likert scale (strongly agree, agree, neutral, disagree and strongly disagree). For data analysis purposes, responses were grouped into two categories (agree versus does not agree/disagree). The data were summarized as one-way frequencies and the Pearson chi-square test was used to determine the statistical significance of univariate associations between the survey variables and an outcome measure of the effectiveness of the IDP. Results: Among all respondents, fifty-three percent reported that they are required to complete an IDP while thirty-three percent reported that the tool is helpful to their career development. Further, our data suggests that the IDP is most effective when doctoral students complete the tool with faculty mentors with whom they have a positive relationship. Respondents who are confident about their career plans and who take advantage of career development resources at their institution are also more likely to perceive that the IDP is useful for their career development. Conclusion: Given the nuanced use and effectiveness of the IDP, we call for additional research to characterize the overall use and effectiveness of the IDP and to determine whether there are unintended negative consequences created through the use of the tool. Furthermore, we recommend an enhancement of career development infrastructure that would include mentorship training for faculty in order to provide substantially more career planning support to trainees.

scholarly journals Associations between Modifiable Health-Risk Behaviors and Personality Types

2017 ◽  
Vol 8 (2) ◽  
Author(s):  
Jon C. Schommer ◽  
Paul D. Tieger ◽  
Anthony W. Olson ◽  
Lawrence M. Brown
Keyword(s):  
Health Risk ◽  
Risk Behaviors ◽  
Statistical Significance ◽  
Personality Type ◽  
Health Risk Behaviors ◽  
Personality Types ◽  
Chi Square ◽  
Related Stress ◽  
The Individual ◽  
Chi Square Analysis

Objectives: The first objective for this study was to explore if characteristics of personality type (using the Preferred Communication Style Questionnaire) are associated with the following modifiable health-risk behaviors: smoking, exercise, alcohol consumption, nutrition, sleep, depression-related stress, anxiety-related stress, healthcare professional usage, and self-discipline. The second objective for this study was to explore if characteristics of personality type are associated with (1) the quality of patient-physician relationships, (2) patient-physician communication, and (3) preferred method for receiving information. Methods: Data were collected from 10,500 adult individuals residing in the United States via an on-line, self-administered survey coordinated by Qualtrics Panels from March 14-30, 2016. Chi-square analysis was used for making comparisons between categories of personality types and items related to health-risk behaviors. Statistical significance was set at p < 0.05. However, chi-square analysis with large sample sizes (e.g. 10,500 in this study) readily yields statistical significance. Practical significance was set at four or more percentage points above or below the overall mean. Results: Regarding objective 1, personality type was associated with all nine health-risk behaviors studied. Personality types within the Experiencer temperament (17% of the U.S. population) accounted for 46% of the undesirable scores we computed for health-risk behaviors. The Idealist temperament (17% of population) accounted for 32% of the undesirable scores. Conceptualizers (10% of population) accounted for 17% of the undesirable scores and Traditionalists (46% of population) accounted for 5% of the undesirable scores. Regarding objective 2, the findings showed that personality type was associated with (1) the importance people place on the patient-physician relationship, (2) which characteristics of that relationship are most desirable, (3) desire for more communication with their physician, and (4) the preferred method for receiving information. Discussion and Conclusions: Precision medicine has been proposed as a way to create a new taxonomy of disease that uses individual specific data to develop accurate diagnosis, targeted treatment, and improved health outcomes. Based on the findings of this study, we propose that inclusion of personality type is an important component of these efforts so that the health care system can conform more to the individual patient in order to increase engagement and adherence, reduce errors, minimize ineffective treatment and waste, and can be cost effective. Conflict of Interest Co-author, Paul Tieger is CEO of SpeedReading People, LLC which holds copyright for the Individual Wellness Plan and Adherence Predictive Index tools that are mentioned in this manuscript.   Type: Original Research

scholarly journals Combinatorial Interpretations for Rank-Two Cluster Algebras of Affine Type

10.37236/933 ◽  
2007 ◽  
Vol 14 (1) ◽  
Author(s):  
Gregg Musiker ◽  
James Propp
Keyword(s):  
Lie Algebras ◽  
Cluster Algebras ◽  
Laurent Polynomials ◽  
Finite Dimensional ◽  
Combinatorial Interpretations ◽  
Rank 2 ◽  
The Individual ◽  
Affine Type ◽  
Positive Integers ◽  
Two Parameter

Fomin and Zelevinsky show that a certain two-parameter family of rational recurrence relations, here called the $(b,c)$ family, possesses the Laurentness property: for all $b,c$, each term of the $(b,c)$ sequence can be expressed as a Laurent polynomial in the two initial terms. In the case where the positive integers $b,c$ satisfy $bc < 4$, the recurrence is related to the root systems of finite-dimensional rank $2$ Lie algebras; when $bc>4$, the recurrence is related to Kac-Moody rank $2$ Lie algebras of general type. Here we investigate the borderline cases $bc=4$, corresponding to Kac-Moody Lie algebras of affine type. In these cases, we show that the Laurent polynomials arising from the recurence can be viewed as generating functions that enumerate the perfect matchings of certain graphs. By providing combinatorial interpretations of the individual coefficients of these Laurent polynomials, we establish their positivity.

scholarly journals Consistency and Heterogeneity of Individual Behavior under Uncertainty

2007 ◽  
Vol 97 (5) ◽  
pp. 1921-1938 ◽  
Author(s):  
Syngjoo Choi ◽  
Raymond Fisman ◽  
Douglas Gale ◽  
Shachar Kariv
Keyword(s):  
Utility Function ◽  
Portfolio Choice ◽  
Individual Behavior ◽  
Parameter Estimates ◽  
Individual Subject ◽  
Individual Level ◽  
Study Behavior ◽  
The Individual ◽  
Two Parameter ◽  
Good Interpretation

By using graphical representations of simple portfolio choice problems, we generate a very rich dataset to study behavior under uncertainty at the level of the individual subject. We test the data for consistency with the maximization hypothesis, and we estimate preferences using a two-parameter utility function based on Faruk Gul (1991). This specification provides a good interpretation of the data at the individual level and can account for the highly heterogeneous behaviors observed in the laboratory. The parameter estimates jointly describe attitudes toward risk and allow us to characterize the distribution of risk preferences in the population. (JEL D11, D14, D81, G11)

Idiom variation and decomposability Part II: Variation in the noun phrase

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Attila Cserép
Keyword(s):  
Noun Phrase ◽  
American English ◽  
Statistical Significance ◽  
Dependence Relation ◽  
Number Variation ◽  
The Individual

AbstractVariant forms of idioms have been extracted from an American English corpus of 450 million words to test the idiom decomposition hypothesis, which proposes a dependence relation between the degree of idiom decomposability and the extent to which expressions are variable. The more decomposable the idiom is, the more flexibility it is expected to exhibit. In this second part of the study, morphological flexibility (number and determiner) as well as lexico- syntactic flexibility (the addition of various pre- and postmodifiers) of the noun have been assessed and related to three decomposability rankings. The results provide some support for the hypothesis. Of the individual flexibility dimensions, only number variation has been found to be significantly dependent on scalar decomposability. Of the overall measures, noun morphology and overall noun variation are significantly correlated. The relation between overall modifier variation and scalar decomposability is close to statistical significance, although premodifier and postmodifier variations taken separately do not show any dependence. None of the variation measures appear to be related to categorical decomposability.

Analytic Approximations to Nonlinear Boundary Value Problems Modeling Beam-Type Nano-Electromechanical Systems

2017 ◽  
Vol 72 (3) ◽  
pp. 201-206
Author(s):  
Li Zou ◽  
Songxin Liang ◽  
Yawei Li ◽  
David J. Jeffrey
Keyword(s):  
Boundary Value Problems ◽  
Nonlinear Boundary ◽  
Boundary Value ◽  
Parameter Method ◽  
Nonlinear Boundary Value Problems ◽  
Electromechanical Systems ◽  
Adomian Decomposition ◽  
Nonlinear Boundary Value ◽  
Beam Type ◽  
Two Parameter

AbstractNonlinear boundary value problems arise frequently in physical and mechanical sciences. An effective analytic approach with two parameters is first proposed for solving nonlinear boundary value problems. It is demonstrated that solutions given by the two-parameter method are more accurate than solutions given by the Adomian decomposition method (ADM). It is further demonstrated that solutions given by the ADM can also be recovered from the solutions given by the two-parameter method. The effectiveness of this method is demonstrated by solving some nonlinear boundary value problems modeling beam-type nano-electromechanical systems.

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