Development of a chemical heater for a Mars rough-landing capsule

Chemical reaction heater for Mars rough-landing capsul

Influence of Iron on Production of the Antibacterial Compound Tropodithietic Acid and Its Noninhibitory Analog in <i>Phaeobacter inhibens</i>

Tropodithietic acid (TDA) is an antibacterial compound produced by some Phaeobacter and Ruegeria spp. of the Roseobacter clade. TDA production is studied in marine broth or agar since antibacterial activity in other media is not observed. The purpose of this study was to determine how TDA production is influenced by substrate components. High concentrations of ferric citrate, as present in marine broth, or other iron sources were required for production of antibacterially active TDA. However, when supernatants of noninhibitory, low-iron cultures of Phaeobacter inhibens were acidified, antibacterial activity was detected in a bioassay. The absence of TDA in nonacidified cultures and the presence of TDA in acidified cultures were verified by liquid chromatography–high-resolution mass spectrometry. A noninhibitory TDA analog (pre-TDA) was produced by P. inhibens, Ruegeria mobilis F1926, and Phaeobacter sp. strain 27-4 under low-iron concentrations and was instantaneously converted to TDA when pH was lowered. Production of TDA in the presence of Fe(3+) coincides with formation of a dark brown substance, which could be precipitated by acid addition. From this brown pigment TDA could be liberated slowly with aqueous ammonia, and both direct-infusion mass spectrometry and elemental analysis indicated a [Fe(III)(TDA)(2)](x) complex. The pigment could also be produced by precipitation of pure TDA with FeCl(3). Our results raise questions about how biologically active TDA is produced in natural marine settings where iron is typically limited and whether the affinity of TDA to iron points to a physiological or ecological function of TDA other than as an antibacterial compound

Evaluation of candidate probiotic strains for gilthead sea bream larvae (Sparus aurata) using an in vivo approach

Aims: The aim of this study was to evaluate the effect of six bacterial strains on gilthead sea bream larvae (Sparus aurata). Methods and Results: Six bacterial strains isolated from well-performing live food cultures were identified by sequencing fragments of their 16s rDNA genome to the genus level as Cytophaga sp., Roseobacter sp., Ruergeria sp., Paracoccus sp., Aeromonas sp. and Shewanella sp. Survival rates of gilthead sea bream larvae transferred to seawater added these bacterial strains at concentrations of 6 +/- 0.3 x 10(5) bacteria ml(-1) were similar to those of larvae transferred to sterilized seawater and showed an average of 86% at 9 days after hatching, whereas, survival rates of larvae transferred to filtered seawater were lower (P < 0.05), and showed an average of 39%, 9 days after hatching. Conclusion: Several bacterial strains isolated from well-performing live food cultures showed a positive effect for sea bream larvae when compared with filtered seawater. Significance and Impact of the Study: The approach used in this study could be applied as an in vivo evaluation method of candidate probiotic strains used in the rearing of marine fish larvae

Validating an Agency-based Tool for Measuring Women’s Empowerment in a Complex Public Health Trial in Rural Nepal

Despite the rising popularity of indicators of women’s empowerment in global development programmes, little work has been done on the validity of existing measures of such a complex concept. We present a mixed methods validation of the use of the Relative Autonomy Index for measuring Amartya Sen’s notion of agency freedom in rural Nepal. Analysis of think-aloud interviews (n = 7) indicated adequate respondent understanding of questionnaire items, but multiple problems of interpretation including difficulties with the four-point Likert scale, questionnaire item ambiguity and difficulties with translation. Exploratory Factor Analysis of a calibration sample (n = 519) suggested two positively correlated factors (r = 0.64) loading on internally and externally motivated behaviour. Both factors increased with decreasing education and decision-making power on large expenditures and food preparation. Confirmatory Factor Analysis on a validation sample (n = 509) revealed good fit (Root Mean Square Error of Approximation 0.05–0.08, Comparative Fit Index 0.91–0.99). In conclusion, we caution against uncritical use of agency-based quantification of women’s empowerment. While qualitative and quantitative analysis revealed overall satisfactory construct and content validity, the positive correlation between external and internal motivations suggests the existence of adaptive preferences. High scores on internally motivated behaviour may reflect internalized oppression rather than agency freedom

Do Participatory Learning and Action Women’s Groups Alone or Combined with Cash or Food Transfers Expand Women’s Agency in Rural Nepal?

Participatory learning and action women’s groups (PLA) have proven effective in reducing neonatal mortality in rural, high-mortality settings, but their impacts on women’s agency in the household remain unknown. Cash transfer programmes have also long targeted female beneficiaries in the belief that this empowers women. Drawing on data from 1309 pregnant women in a four-arm cluster-randomised controlled trial in Nepal, we found little evidence for an impact of PLA alone or combined with unconditional food or cash transfers on women’s agency in the household. Caution is advised before assuming PLA women’s groups alone or with resource transfers necessarily empower women

A theory of change for community interventions to prevent domestic violence against women and girls in Mumbai, India [version 1; peer review: 2 approved with reservations]

Background: We describe the development of a theory of change for community mobilisation activities to prevent violence against women and girls. These activities are part of a broader program in urban India that works toward primary, secondary, and tertiary prevention of violence and includes crisis response and counselling and medical, police, and legal assistance. / Methods: The theory of change was developed in five phases, via expert workshops, use of primary data, recurrent team meetings, adjustment at further meetings and workshops, and a review of published theories. / Results: The theory summarises inputs for primary and secondary prevention, consequent changes (positive and negative), and outcomes. It is fully adapted to the program context, was designed through an extended consultative process, emphasises secondary prevention as a pathway to primary prevention, and integrates community activism with referral and counselling interventions. / Conclusions: The theory specifies testable causal pathways to impact and will be evaluated in a controlled trial