Classification of Minimal Separating Sets in Low Genus Surfaces

Consider a surface $S$ and let $M\subset S$. If $S\setminus M$ is not connected, then we say $M$ \emph{separates} $S$, and we refer to $M$ as a \emph{separating set} of $S$. If $M$ separates $S$, and no proper subset of $M$ separates $S$, then we say $M$ is a \emph{minimal separating set} of $S$. In this paper we use methods of computational combinatorial topology to classify the minimal separating sets of the orientable surfaces of genus $g=2$ and $g=3$. The classification for genus 0 and 1 was done in earlier work, using methods of algebraic topology.Comment: 24 pages, 5 figures, 2 tables (11 pages

What's the point of knowing how?

Why is it useful to talk and think about knowledge-how? Using Edward Craig’s discussion of the function of the concepts of knowledge and knowledge-how as a jumping off point, this paper argues that considering this question can offer us new angles on the debate about knowledge-how. We consider two candidate functions for the concept of knowledge-how: pooling capacities, and mutual reliance. Craig makes the case for pooling capacities, which connects knowledge-how to our need to pool practical capacities. I argue that the evidence is much more equivocal. My suggested diagnosis is that the concept of knowledge-how plays both functions, meaning that the concept of knowledge-how is inconsistent, and that the debate about knowledge-how is at least partly a metalinguistic negotiation. In closing, I suggest a way to revise the philosophical concept of knowledge how

Stroke Caregiver Outcomes from the Telephone Assessment and Skill-Building Kit (TASK)

Purpose: Stroke caregivers often express the need for information about stroke and assistance with stroke-related care in the early discharge period. The Telephone Assessment and Skill-Building Kit (TASK) is an 8-week program that addresses caregiver needs. This study explored the efficacy of the TASK program in improving stroke caregiver outcomes. Method: Guided by a conceptual model, 6 outcomes (optimism, task difficulty, threat appraisal, depressive symptoms, life changes, general health perceptions) were measured in 40 caregivers randomized to the TASK (n = 21) or an attention control group (n = 19). Data were analyzed using analysis of covariance (ANCOVA), controlling for baseline scores and minutes spent with the nurse. Results: Significant increases in optimism at 4 weeks, 8 weeks, and 12 weeks were found, with medium effect sizes for the TASK group relative to the control group (p < .05). Significant improvements in task difficulty at 4 weeks, and threat appraisal at both 8 weeks and 12 weeks were also found (p < .05). Conclusion: Caregivers receiving the TASK intervention improved in optimism, task difficulty, and threat appraisal. Further testing of an enhanced version of the TASK program is warranted, with attention directed toward more distal stroke caregiver outcomes

Content Validity and Satisfaction With a Stroke Caregiver Intervention Program

Background and Purpose Establishing evidence of content validity and satisfaction is an integral part of intervention research. The purpose of this article is to describe content validity and satisfaction relative to the Telephone Assessment and Skill-Building Kit (TASK), an 8-week follow-up program based on individualized assessment of stroke caregiver needs. Design and Methods The TASK intervention enables caregivers to develop skills based on assessment of their own needs. During the development of the TASK program, 10 experts rated the validity of the TASK intervention components for accuracy, feasibility, acceptability, and problem relevance. After incorporating feedback from the experts, a randomized controlled clinical trial was instituted using a convenience sample of 40 stroke caregivers to determine satisfaction (usefulness, case of use, and acceptability) with the TASK intervention (n=21) compared with an attention control group (n=19). Data collection occurred between March 2005 and June 2006. Data were analyzed using descriptive statistics, independent sample t tests, and content analysis. Findings Expert ratings on a 1 to 5 scale, with 5 being strongly agree, provided evidence of content validity (accuracy 4.71, feasibility 4.46, acceptability 4.40, problem relevance 4.67). Caregivers in the TASK group scored significantly higher than the attention control group on all satisfaction measures (usefulness p=.02; ease of use p=.02; acceptability p=.05). Qualitative comments from caregivers provided further evidence of satisfaction. Conclusions Evidence of content validity and user satisfaction for the TASK intervention relative to an attention control group was found. Clinical Relevance The TASK program may be a viable telephone-based program that can be implemented by nurses to support family caregivers during the first few months after stroke survivors are discharged home

Preliminary Efficacy of a Stroke Caregiver Intervention Program for Reducing Depressive Symptoms

poster abstractBackground and Purpose: Stroke caregivers who lack skills because of unmet needs are at increased risk for depressive symptoms; which can impede rehabilitation of the survivor and increase the survivor’s risk for costly, long-term institutionalization. The Telephone Assessment and Skill-Building Kit (TASK) is an 8-week follow-up program based on individualized assessment of caregiver needs. The purpose of this study was to explore preliminary efficacy of the TASK program for improving stroke caregiver depressive symptoms. Methods: A subgroup of 15 caregivers who screened positive for mild to severe depressive symptoms at baseline (PHQ-9 > 5) were randomized to the TASK program (n=8) or an attention control group (n=7). Data were analyzed using Univariate ANCOVA, controlling for baseline scores and number of minutes spent with the nurse for each timepoint (4, 8, and 12 weeks after baseline). Partial ƞ2 was used to estimate effect sizes (.25 large). Results: Although not statistically significant because of the small sample size, medium to large improvements based on effect sizes were found in depressive symptoms for the TASK group relative to the control group at 4 weeks [F(1,11) = 4.15, p=.07, ƞ2=.27], 8 weeks [F(1,11) = 1.66, p=.22, ƞ2=.13], and 12 weeks after baseline [F(1,11) = 1.47, p=.25, ƞ2 =.12]. Adjusted PHQ-9 means for the TASK group at 4, 8, and 12 weeks ranged from 4.9 to 5.9; adjusted PHQ-9 means for the control group at 4, 8, and 12 weeks ranged from 9.0 to 10.8. Conclusions: Caregivers in the TASK group reduced their depressive symptoms to the mild range, while caregivers in the control group maintained their scores primarily in the moderately depressed range. Further testing of the TASK program in a larger randomized controlled clinical trial is warranted and is currently underway

Inducing Partner Preference in Mice by Chemogenetic Stimulation of CA2 Hippocampal Subfield

Social recognition is fundamental for social decision making and the establishment of long-lasting affiliative behaviors in behaviorally complex social groups. It is a critical step in establishing a selective preference for a social partner or group member. C57BL/6J lab mice do not form monogamous relationships, and typically do not show prolonged social preferences for familiar mice. The CA2 hippocampal subfield plays a crucial role in social memory and optogenetic stimulation of inputs to the dorsal CA2 field during a short memory acquisition period can enhance and extend social memories in mice. Here, we show that partner preference in mice can be induced by chemogenetic selective stimulation of the monosynaptic projections from the hypothalamic paraventricular nucleus (PVN) to the CA2 during the cohabitation period. Specifically, male mice spend more time in social contact, grooming and huddling with the partner compared to a novel female. Preference was not induced by prolonging the cohabitation period and allowing more time for social interactions and males to sire pups with the familiar female. These results suggest that PVN-to-CA2 projections are part of an evolutionarily conserved neural circuitry underlying the formation of social preference and may promote behavioral changes with appropriate stimulation

High-Precision Measurement of the 19Ne Half-Life and Implications for Right-Handed Weak Currents

We report a precise determination of the 19Ne half-life to be $T_{1/2} = 17.262 \pm 0.007$ s. This result disagrees with the most recent precision measurements and is important for placing bounds on predicted right-handed interactions that are absent in the current Standard Model. We are able to identify and disentangle two competing systematic effects that influence the accuracy of such measurements. Our findings prompt a reassessment of results from previous high-precision lifetime measurements that used similar equipment and methods.Comment: 5 pages and 5 figures. Paper accepted for publication in Phys. Rev. Let