234 research outputs found
Comparative Ultrastructure Of Digestive Diverticulae In Bathymodiolin Mussels: Discovery Of An Unknown Spherical Inclusion (Six) In Digestive Cells Of A Seep Mussel
Mussels in the genus Bathymodiolus host endosymbiotic bacteria in their gills, from which the mussel derives much of its nutrition. Bathymodiolin mussels also have functional digestive systems and, as in shallow-water mytilid mussels, cells of the digestive diverticulae are of two types: basophilic secretory cells and columnar digestive cells. Cellular contents of secretory and digestive cells of Bathymodiolus thermophilus and Bathymodiolus brevior from deep-sea hydrothermal vents are comparable to cellular contents of these cell types observed in shallow-water mytilids. In the seep mussel Bathymodiolus heckerae, cellular contents of columnar cells were anomalous, being dominated by an unknown cellular inclusion herein called spherical inclusion unknown or SIX. SIX was observed in all digestive cells and some basophilic cells of B. heckerae examined with TEM. It is a large (2-10-mu m diameter) and abundant (7 +/- 1.5 inclusions per epithelial cell section) inclusion, with a double external membrane and stacked internal lamellae. No microbial DNA was detected in digestive tubules of B. heckerae using molecular probes, preferential DNA amplification techniques, or DAPI staining, suggesting that SIX is not a unicellular parasite or symbiont. The ubiquity and abundance of SIX within cells of the digestive diverticula suggest that it has an important cellular function (positive or negative), yet to be determined
ASYMMETRIC LEAVES1 regulates abscission zone placement in Arabidopsis flowers
BACKGROUND: The sepals, petals and stamens of Arabidopsis flowers detach via abscission zones formed at their boundaries with the underlying receptacle. The ASYMMETRIC LEAVES1 (AS1) MYB transcription factor plays a critical role in setting boundaries between newly formed leaf primordia and the shoot meristem. By repressing expression of a set of KNOTTED1-LIKE HOMEODOMAIN (KNOX) genes from developing leaf primordia, AS1 and its partner ASYMMETRIC LEAVES2 allow the patterning and differentiation of leaves to proceed. Here we show a unique role for AS1 in establishing the positions of the sepal and petal abscission zones in Arabidopsis flowers. RESULTS: In as1 mutant flowers, the sepal abscission zones are displaced into inverted V-shaped positions, leaving behind triangular stubs of tissue when the organs abscise. Movement of the petal abscission zones is also apparent. Abscission of the medial sepals is delayed in as1 flowers; loss of chlorophyll in the senescing sepals contrasts with proximal zones that remain green. AS1 has previously been shown to restrict expression of the KNOX gene, BREVIPEDICELLUS (BP), from the sepals. We show here that loss of BP activity in as1 flowers is sufficient to restore the positions of the sepal and petal abscission zones, the sepal-receptacle boundary of the medial sepals and the timing of their abscission. CONCLUSIONS: Our results indicate that AS1 activity is critical for the proper placement of the floral organ abscission zones, and influences the timing of organ shedding
Caregiver Satisfaction with a Video Telehealth Home Safety Evaluation for Dementia
Family caregivers are vital to telehealth-delivered dementia care. The objective of this mixed methods descriptive study conducted in the VA Bedford Healthcare System was to examine caregiver satisfaction with a video telehealth dementia home safety occupational therapy evaluation. Ten caregivers of Veterans with dementia participated. Ratings of caregiver satisfaction, measured by nine Likert scale items including ability to see and hear, were examined in relation to person and visit-related contextual factors extracted from RA field notes, to develop an in-depth understanding of caregiver experience. Person factors included caregiver age and gender and Veteran cognitive status. Visit-related contextual factors included occurrence  of technical glitches. Caregiver visit satisfaction was overall positive, with exceptions related to technological glitches and the presence of the person with dementia during the visit. Veteran cognitive status appeared to influence caregiver satisfaction. Implications of the study are that proactively addressing technical glitches and incorporating dementia stage-specific approaches may optimize caregiversâ telehealth experience.
Providers\u27 response to child eating behaviors: A direct observation study
Child care providers play an important role in feeding young children, yet little is known about childrenâs influence on providersâ feeding practices. This qualitative study examines provider and child (18 months â4 years) feeding interactions. Trained data collectors observed 200 eating occasions in 48 family child care homes and recorded providersâ responses to childrenâs meal and snack time behaviors. Child behaviors initiating provider feeding practices were identified and practices were coded according to higher order constructs identified in a recent feeding practices content map. Analysis examined the most common feeding practices providers used to respond to each child behavior. Providers were predominately female (100%), African-American (75%), and obese (77%) and a third of children were overweight/obese (33%). Commonly observed child behaviors were: verbal and non-verbal refusals, verbal and non-verbal acceptance, being âall doneâ, attempts for praise/attention, and asking for seconds. Childrenâs acceptance of food elicited more autonomy supportive practices vs. coercive controlling. Requests for seconds was the most common behavior, resulting in coercive controlling practices (e.g., insisting child eat certain food or clean plate). Future interventions should train providers on responding to childrenâs behaviors and helping children become more aware of internal satiety and hunger cues
Providersâ response to child eating behaviors: A direct observation study
Child care providers play an important role in feeding young children, yet little is known about childrenâs influence on providersâ feeding practices. This qualitative study examines provider and child (18 months -4 years) feeding interactions. Trained data collectors observed 200 eating occasions in 48 family childcare homes and recorded providersâ responses to childrenâs meal and snack time behaviors. Child behaviors initiating provider feeding practices were identified and practices were coded according to higher order constructs identified in a recent feeding practices content map. Analysis examined the most common feeding practices providers used to respond to each child behavior. Providers were predominately female (100%), African-American (75%), and obese (77%) and a third of children were overweight/obese (33%). Commonly observed child behaviors were: verbal and non-verbal refusals, verbal and non-verbal acceptance, being âall doneâ, attempts for praise/attention, and asking for seconds. Childrenâs acceptance of food elicited more autonomy supportive practices vs. coercive controlling. Requests for seconds was the most common behavior, resulting in coercive controlling practices (e.g., insisting child eat certain food or clean plate). Future interventions should train providers on responding to childrenâs behaviors and helping children become more aware of internal satiety and hunger cues
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Designing Weather Insurance Contracts for Farmers in Malawi, Tanzania and Kenya: Final Report to the Commodity Risk Management Group, ARD, World Bank
This report presents project products to the Commodity Risk Management Group of the World Bank for the development and evaluation of index insurance contracts for smallholder farmers in Malawi, Tanzania, and Kenya. The development of some products we are providing was supported at no cost by the NSF-funded Center for Research on Environmental Decisions. Index insurance is a relatively new weather risk management tool. While traditional insurance insures against crop failure, index insurance insures for a specific event or risk, such as rainfall deficits. The index insurance can be more cost effective since there is no need for in-field assessment of damage because payouts are triggered by weather data directly. Index insurance addresses two problems associated with traditional crop insurance: moral hazard (incentives for a farmer to let a crop die in order to get an insurance payout) and adverse selection (in which insurance is priced based on the risks of the entire population but only the most vulnerable farmers purchase insurance). However, index insurance only provides partial protection and is therefore only one part of a complete risk management package. It is critical that the client have a comprehensive understanding of exactly what risks are covered (and what risks are not covered) by the index product so that clients can effectively use the insurance as a part of their risk management system. Products must be transparent and completely understandable to the client or they will not be able to play their proper role
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