3,346 research outputs found
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Experimental In-Field Transfer and Survival of Escherichia coli from Animal Feces to Romaine Lettuce in Salinas Valley, California.
This randomized controlled trial characterized the transfer of E. coli from animal feces and/or furrow water onto adjacent heads of lettuce during foliar irrigation, and the subsequent survival of bacteria on the adaxial surface of lettuce leaves. Two experiments were conducted in Salinas Valley, California: (1) to quantify the transfer of indicator E. coli from chicken and rabbit fecal deposits placed in furrows to surrounding lettuce heads on raised beds, and (2) to quantify the survival of inoculated E. coli on Romaine lettuce over 10 days. E. coli was recovered from 97% (174/180) of lettuce heads to a maximal distance of 162.56 cm (5.33 ft) from feces. Distance from sprinklers to feces, cumulative foliar irrigation, and lettuce being located downwind of the fecal deposit were positively associated, while distance from fecal deposit to lettuce was negatively associated with E. coli transference. E. coli exhibited decimal reduction times of 2.2 and 2.5 days when applied on the adaxial surface of leaves within a chicken or rabbit fecal slurry, respectively. Foliar irrigation can transfer E. coli from feces located in a furrow onto adjacent heads of lettuce, likely due to the kinetic energy of irrigation droplets impacting the fecal surface and/or impacting furrow water contaminated with feces, with the magnitude of E. coli enumerated per head of lettuce influenced by the distance between lettuce and the fecal deposit, cumulative application of foliar irrigation, wind aspect of lettuce relative to feces, and time since final irrigation. Extending the time period between foliar irrigation and harvest, along with a 152.4 cm (5 ft) no-harvest buffer zone when animal fecal material is present, may substantially reduce the level of bacterial contamination on harvested lettuce
Human Cytomegalovirus US28: A Functionally Selective Chemokine Binding Receptor
The Human Cytomegalovirus (HCMV)-encoded chemokine receptor US28 is the most well-characterized of the four chemokine receptor-like molecules found in the HCMV genome. US28 been studied as an important virulence factor for HCMV-mediated vascular disease and, more recently, in models of HCMV-associated malignancy. US28 is a rare multi-chemokine family binding receptor with the ability to bind ligands from two distinct chemokine classes. Ligand binding to US28 activates cell-type and ligand-specific signaling pathways leading to cellular migration, an example receptor functional selectivity. Additionally, US28 has been demonstrated to constitutively activate PLC and NFkB. Understanding the structure/function relationships between US28, its ligands and intracellular signaling molecules will provide essential clues for effective pharmacological targeting this multifunctional chemokine receptor
The Clock affecting 1 mutation of Neurospora is a recurrence of the frq\u3csup\u3e7\u3c/sup\u3e mutation7
The clock affecting-1 (cla-1) mutation of Neurospora crassa increases the period and decreases temperature compensation of the circadian rhythm, and was thought to define an uncloned gene with a possible role in the Neurospora clock. This defect, thought to be due to a translocation, was associated with a slow growth rate and a period of about 27 h at 25cla-1 and found the growth rate and period defects to be due to linked independent mutations. The translocation was not the cause of the long period. The csp-1 mutation, present in the original cla-1 strain, had a period shortening effect, thus cla-1 strains lacking csp-1 had a period length similar to that of frequency7 (frq7). The cla-1 period defect mapped to the frq locus, and sequencing of frq revealed cla-1 to be a re-isolation of frq7
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Husband's Alcohol Use, Intimate Partner Violence, and Family Maltreatment of Low-Income Postpartum Women in Mumbai, India.
Husbands' alcohol use has been associated with family-level stress and intimate partner violence (IPV) against women in India. Joint family systems are common in India and IPV often co-occurs with non-violent family maltreatment of wives (e.g., nutritional deprivation, deprivation of sleep, blocking access to health care). Alcohol use increases for some parents following the birth of a child. This study examined 1,038 postpartum women's reports of their husbands' alcohol use and their own experiences of IPV (by husband) and non-violent maltreatment from husbands and/or in-laws. We analyzed cross-sectional, quantitative data collected in 2008, from women (ages 15-35) seeking immunizations for their infants <6 months at three large urban health centers in Mumbai, India. Crude and adjusted logistic regression models estimated associations between the independent variable (husbands' past month use of alcohol) and two dependent variables (postpartum IPV and maltreatment). Overall, 15% of husbands used alcohol, ranging from daily drinkers (10%) to those who drank one to two times per week (54%). Prevalence of postpartum IPV and family maltreatment was 18% and 42%, respectively. Prevalence of IPV among women married to alcohol users was 27%. Most abused women's husbands always (27%) or sometimes (37%) drank during violent episodes. Risk for IPV increased with a man's increasing frequency of consumption. Women who lived with a husband who drank alcohol, relative to non-drinkers, were more likely to report postpartum IPV, aOR = 2.0, 95% confidence interval (CI) = [1.3, 3.1]. Husbands' drinking was marginally associated with increased risk for family maltreatment, aOR = 1.4, 95% CI = [1.0, 2.1]. Our findings suggest that men's alcohol use is an important risk factor for postpartum IPV and maltreatment. Targeted services for Indian women contending with these issues are implicated. Postpartum care offers an ideal opportunity to screen for IPV, household maltreatment, and other health risks, such as husband's use of alcohol. There is need to scale up proven successful interventions for reducing men's alcohol use and design strategies that provide at-risk women protection from alcohol-related IPV
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Meiotic cellular rejuvenation is coupled to nuclear remodeling in budding yeast.
Production of healthy gametes in meiosis relies on the quality control and proper distribution of both nuclear and cytoplasmic contents. Meiotic differentiation naturally eliminates age-induced cellular damage by an unknown mechanism. Using time-lapse fluorescence microscopy in budding yeast, we found that nuclear senescence factors - including protein aggregates, extrachromosomal ribosomal DNA circles, and abnormal nucleolar material - are sequestered away from chromosomes during meiosis II and subsequently eliminated. A similar sequestration and elimination process occurs for the core subunits of the nuclear pore complex in both young and aged cells. Nuclear envelope remodeling drives the formation of a membranous compartment containing the sequestered material. Importantly, de novo generation of plasma membrane is required for the sequestration event, preventing the inheritance of long-lived nucleoporins and senescence factors into the newly formed gametes. Our study uncovers a new mechanism of nuclear quality control and provides insight into its function in meiotic cellular rejuvenation
Self-Concept Clarity and the Bodily Self: Malleability Across Modalities
The self has fascinated scholars for centuries. Although theory suggests that the self-concept (cognitive self-understanding) and bodily self (pre-reflective awareness of one’s body) are related, little work has examined this notion. To this end, in Study 1, participants reported on self-concept clarity (SCC) and completed the rubber hand illusion (RHI), a paradigm in which synchronous (vs. asynchronous) stimulation between a prosthetic hand and one’s own hand leads one to “embody” the prosthetic hand. Whereas participants were equally susceptible to the RHI during synchronous stroking, low-SCC individuals were more vulnerable to the illusion during asynchronous stroking, when the effect is unwarranted. Conceptually replicating and extending this finding, in Study 2, low-SCC individuals were more susceptible to the body-swap illusion—the impression that another person’s body is one’s own. These findings suggest that a clear sense of self implies clarity and stability of both the self-concept and the bodily self
Micro-Rockets for the Classroom
Many people are fascinated with rocketry, as evidenced by hundreds of thousands of visitors to the Kennedy Space Center for Space Shuttle launches. Rockets demonstrate important basic principles of chemistry, engineering, and physics 1-5. Even model rockets are exciting to launch. Many physics teachers take advantage of this and use model solid fuel, 6 - 10 and water rockets 11-14 in their teaching activities. Scientific supply companies have responded to this interest and offer a range of equipment to investigate model rocket performance. 6,10,12,15 This note describes miniature solid fuel, or micro rockets, which are made from a single safety match, oil or paraffin, and aluminum foil. These micro-rockets have a range of up to 6 meters, and can be safely launched from a candle flame inside classrooms
Variation In Weddell Seal Pup Mass: Maternal Investment In Offspring
Life history theory predicts that individuals face physiological tradeoffs between current and future reproduction. These tradeoffs ultimately lead to reproductive costs which can affect survival, fecundity, condition of the female and offspring survival. Reproduction itself is costly and involves a number of sequential physiological processes that require different levels of energetic investment. In mammalian species gestation and lactation require the most energy and energy expenditure during these times is a characteristic of females and can vary among individuals. Mass measurements, used to quantify pre- and post-partum maternal investment, were collected from 887 Weddell seal (Leptonychotes weddellii) pups at parturition and throughout lactation in Erebus Bay, Antarctica during the 2002 through 2010 field seasons. Preliminary analysis demonstrated high individual variation in pup mass within a season and modest variation among seasons suggesting that pup mass may be affected more by individual animal attributes than annual variation in environmental conditions. This variation in maternal investment was investigated using maternal traits taken from the long term database. We found that maternal traits have different affects on pup mass at different stages of investment. Maternal age and birth date were found to be influential on pre- and post-partum investment along with age at first reproduction on pre-natal investment and breeding status the previous year on post-natal investment. The variation in the influence of maternal traits on maternal investment may be due to the increased energy requirement of lactation and reproductive costs that females accrue throughout their lifetime
VEGF-A and Semaphorin3A: Modulators of vascular sympathetic innervation
AbstractSympathetic nerve activity regulates blood pressure by altering peripheral vascular resistance. Variations in vascular sympathetic innervation suggest that vascular-derived cues promote selective innervation of particular vessels during development. As axons extend towards peripheral targets, they migrate along arterial networks following gradients of guidance cues. Collective ratios of these gradients may determine whether axons grow towards and innervate vessels or continue past non-innervated vessels towards peripheral targets. Utilizing directed neurite outgrowth in a three-dimensional (3D) co-culture, we observed increased axon growth from superior cervical ganglion explants (SCG) towards innervated compared to non-innervated vessels, mediated in part by vascular endothelial growth factor (VEGF-A) and Semaphorin3A (Sema3A) which both signal via neuropilin-1 (Nrp1). Exogenous VEGF-A, delivered by high-expressing VEGF-A–LacZ vessels or by rhVEGF-A/alginate spheres, increased sympathetic neurite outgrowth while exogenous rhSema3A/Fc decreased neurite outgrowth. VEGF-A expression is similar between the innervated and non-innervated vessels examined. Sema3A expression is higher in non-innervated vessels. Spatial gradients of Sema3A and VEGF-A may promote differential Nrp1 binding. Vessels expressing high levels of Sema3A favor Nrp1-PlexinA1 signaling, producing chemorepulsive cues limiting sympathetic neurite outgrowth and vascular innervation; while low Sema3A expressing vessels favor Nrp1-VEGFR2 signaling providing chemoattractive cues for sympathetic neurite outgrowth and vascular innervation
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