1,129 research outputs found
Collective action and participation in irrigation water management: A case study of Mooi River Irrigation Scheme in KwaZulu-Natal Province, South Africa
In line with the current focus of most developing countries to transfer management of communal irrigation schemes from state to users, an understanding of the determinants of farmer participation in collective activities forms the basis to improve the management of previously government-funded schemes, which are characterised by poor maintenance and performance when farmers are left to manage the schemes on their own. Cross-sectional data collected from 307 respondents in the Mooi River Irrigation Scheme (MRIS) in KwaZulu-Natal were used to identify the determinants of farmer participation in collective activities. The results of the Tobit and Ordered Probit models suggest that collective activities are negatively affected by low farmer-literacy levels. Number of consecutive days that farmers spend without access to irrigation water per week was used as a proxy for water scarcity, and was confirmed to be a significant determinant of farmer participation. The existing incentives for water-users in the MRIS need to be improved to encourage farmer participation in collective water management. This calls for strengthening of local water management systems and institutional policies to ensure maximum benefits from participating in collective activities. The study noted the complexity of managing common pool resources at a localised level, and pointed to the need to further understand the institutional dynamics in which smallholder irrigation farmers operate.Keywords: Collective action, participation intensity, smallholder irrigation scheme, South Afric
Long-term course and outcome of obsessive-compulsive patientsafter cognitive-behavioral therapy in combination with eitherfluvoxamine or placebo: A 7-year follow-up of a randomized double-blind trial
Longitudinal studies with very long follow-up periods of patients with obsessive-compulsive disorder (OCD) who have received adequate treatment are rare. In the current study, 30 of 37 inpatients (81%) with severe OCD were followed up 6-8 years after treatment with cognitive-behavioral therapy (CBT) in combination with either fluvoxamine or placebo in a randomized design. The significant improvements (with large effectsizes) in obsessive-compulsive symptoms from pre- to post-treatment (41% reduction on the Y-BOCS) remained stable at follow-up (45 %). Responder rates, defined as ≥35% reduction on the Y-BOCS, were 67% and 60%, respectively. Depressive symptoms decreased significantly not only from pre- to post-treatment but also during follow-up. Re-hospitalization, which occurred in 11 patients (37 %), was associated with more severe depressive symptoms at pre-treatment and living without a partner. Full symptom remission at follow-up, defined as both Y-BOCS total score ≤ 7 and no longer meeting diagnostic criteria for OCD, was achieved by 8 patients (27 %). Patients without full remission at follow-up had a significantly longer history of OCD, assessed at pretreatment, compared to remitted patients. The shortterm treatment outcome had no predictive value for the long-term course. Throughout the naturalistic follow-up, nearly all patients (29 patients) received additional psychotherapy and/or medication. This might indicate that such chronic OCD patients usually need additional therapeutic support after effective inpatient treatment to maintain their improvements over long period
Fishing for iodine: What aquatic foraging by bonobos tells us about human evolution
Background: Expansion of brain tissue and development of advanced cognitive skills are characteristic traits of human evolution. Their emergence has been causally linked to the intake of nutrients that promote brain development and iodine is considered a critical resource. Rich sources of iodine exist in coastal areas and evolutionary scenarios associate the progressive development of brain size and cognitive skills to such landscapes. This raises the question of how early hominins living in continental areas could have met their iodine requirements. One way to explore this question is to use information from hominoid primates as a proxy for the nutritional ecology of early hominins. Bonobos are particularly interesting in this context as they are restricted to the central part of the Congo basin, an area considered to be iodine deficient based on human standards.
Methods: Pooled samples of fruit, terrestrial and aquatic herbs were used to assess mineral content with an inductively coupled plasma optical emission spectrometer. Iodine content was measured with the catalytic technique of Sandell-Kolthoff and two separate inductively coupled plasma mass spectrometry methods.
Results: Nutritional analyses revealed that the mineral content of aquatic herbs is higher than in other plant foods. Moreover, two species of aquatic herbs consumed by bonobos contain iodine concentrations that are almost equivalent to marine algae.
Conclusions: These data challenge the general notion that the Congo basin is iodine deficient and demonstrate that its lowland forest offers natural sources of iodine in concentrations high enough to prevent iodine deficiency in hominoids and humans
Wannier-Bloch Approach to Localization in High-Harmonics Generation in Solids
Emission of high-order harmonics from solids provides a new avenue in attosecond science. On the one hand, it allows us to investigate fundamental processes of the nonlinear response of electrons driven by a strong laser pulse in a periodic crystal lattice. On the other hand, it opens new paths toward efficient attosecond pulse generation, novel imaging of electronic wave functions, and enhancement of high-order harmonic-generation (HHG) intensity. A key feature of HHG in a solid (as compared to the well-understood phenomenon of HHG in an atomic gas) is the delocalization of the process, whereby an electron ionized from one site in the periodic lattice may recombine in any other. Here, we develop an analytic model, based on the localized Wannier wave functions in the valence band and delocalized Bloch functions in the conduction band. This Wannier-Bloch approach assesses the contributions of individual lattice sites to the HHG process and hence precisely addresses the question of localization of harmonic emission in solids. We apply this model to investigate HHG in a ZnO crystal for two different orientations, corresponding to wider and narrower valence and conduction bands, respectively. Interestingly, for narrower bands, the HHG process shows significant localization, similar to harmonic generation in atoms. For all cases, the delocalized contributions to HHG emission are highest near the band-gap energy. Our results pave the way to controlling localized contributions to HHG in a solid crystal
Multidrug- and extensively drug-resistant tuberculosis
We evaluated risk factors and treatment outcomes associated with multidrug-resistant (MDR) and extensively drug-resistant (XDR) tuberculosis (TB) in Germany in 2004–2006. In 177 (4%) of 4,557 culture-positive TB cases, Mycobacterium tuberculosis isolates were identified as MDR TB; an additional 7 (0.15%) met criteria for XDR TB. Of these 184 patients, 148 (80%) were born in countries of the former Soviet Union. In patients with XDR TB, hospitalization was longer (mean ± SD 202 ± 130 vs. 123 ± 81 days; p = 0.015) and resistance to all first-line drugs was more frequent (36% vs. 86%; p = 0.013) than in patients with MDR TB. Seventy-four (40%) of these 184 patients received treatment with linezolid. Treatment success rates ranged from 59% for the entire cohort (59% for MDR TB and 57% for XDR TB) to 87% for those with a definitive outcome (n = 125; 89% for MDR TB and 80% for XDR TB). Extensive drug susceptibility testing and availability of second- and third-line drugs under inpatient management conditions permit relatively high treatment success rates in MDR- and XDR TB
Placebo Oral Rabies Vaccine Bait Uptake by Small Indian Mongooses (\u3ci\u3eHerpestes auropunctatus\u3c/i\u3e) in Southwestern Puerto Rico
The small Indian mongoose (Herpestes auropunctatus) is a rabies reservoir in areas of the Caribbean including Puerto Rico, but no rabies vaccination program targeting this host exists. We used two derivatives of iophenoxic acid (IPA) to evaluate placebo oral rabies vaccine bait uptake by mongooses in southwestern Puerto Rico. We hand-distributed baits at an application rate of 200 baits/km2 at three, 400 ha, sites during autumn 2016 and spring 2017. Each site contained 90–100 cage traps in a 100 ha central trapping area. We used ethyl-IPA as a biological marker during the autumn and methyl-IPA during the spring. We live captured mongooses for 10 consecutive days, beginning 1 wk following bait application. We obtained a serum sample from captured mongooses and analyzed the sera for ethyl- and methyl-IPA by liquid chromatography mass spectrometry. During autumn 2016, 63% (55/87) mongooses sampled were positive for ethyl-IPA. In spring 2017, 69% (85/123) of mongooses were positive for methyl-IPA. Pooling seasons, accounting for recaptures between years, and disregarding marker type, 74% (133/179) unique mongooses were positive for IPA biomarker, indicating bait consumption during either the autumn, spring, or both trials. We conclude that distributing baits at an application rate of 200 baits/km2 is sufficient to reach over 60% of the target mongoose population in dry forest habitats of Puerto Rico
Astrocyte-derived TGF-beta 2 and NGF differentially regulate neural recognition molecule expression by cultured astrocytes.
Hydrophobically stabilized open state for the lateral gate of the Sec translocon
The Sec translocon is a central component of cellular pathways for protein translocation and membrane integration. Using both atomistic and coarse-grained molecular simulations, we investigate the conformational landscape of the translocon and explore the role of peptide substrates in the regulation of the translocation and integration pathways. Inclusion of a hydrophobic peptide substrate in the translocon stabilizes the opening of the lateral gate for membrane integration, whereas a hydrophilic peptide substrate favors the closed lateral gate conformation. The relative orientation of the plug moiety and a peptide substrate within the translocon channel is similarly dependent on whether the substrate is hydrophobic or hydrophilic in character, and the energetics of the translocon lateral gate opening in the presence of a peptide substrate is governed by the energetics of the peptide interface with the membrane. Implications of these results for the regulation of Sec-mediated pathways for protein translocation vs. membrane integration are discussed
- …