1,716 research outputs found
Residues of Organochlorinated Pesticides in Soil from Tomato Fields, Ngarenanyuki, Tanzania
This work presents the concentrations of five pesticide residues, lindane, chlorpyrifos, endosulfan, p, p'-DDE and p, p'-DDD in soil samples collected from tomato fields in Ngarenanyuki, Tanzania. Endosulfan sulphate was detected in 100 % of the sample analysed with mean concentration of 0.2407 mg/kg dw. Chlorpyrifos was detected in 87 % of the samples with mean concentration of 0.1253 mg/kg dw. p, p'-DDE and p, p'-DDD were detected in 46 and 40 % of the samples analysed with mean concentrations of 0.1482 and 0.154 mg/kg dw, respectively. Lindane was the least detected pesticide. It was detected in 5 (33 %) of soil samples analysed with mean concentration of 0.2126 mg/kg dw. Low concentrations detected indicate the past usage of the pesticides
Modifications of Gait as Predictors of Natural Osteoarthritis Progression in STR/Ort Mice
OBJECTIVE: Osteoarthritis (OA) is a common chronic disease for which disease-modifying therapies are not currently available. Studies to seek new targets for slowing the progress of OA rely on mouse models, but these do not allow for longitudinal monitoring of disease development. This study was undertaken to determine whether gait can be used to measure disease severity in the STR/Ort mouse model of spontaneous OA and whether gait changes are related to OA joint pain. METHODS: Gait was monitored using a treadmill-based video system. Correlations between OA severity and gait at 3 treadmill speeds were assessed in STR/Ort mice. Gait and pain behaviors of STR/Ort mice and control CBA mice were analyzed longitudinally, with monthly assessments. RESULTS: The best speed to identify paw area changes associated with OA severity in STR/Ort mice was found to be 17 cm · seconds(−1). Paw area was modified with age in CBA and STR/Ort mice, but this began earlier in STR/Ort mice and correlated with the onset of OA at 20 weeks of age. In addition, task noncompliance appeared at 20 weeks. Surprisingly, STR/Ort mice did not show any signs of pain with OA development, even when treated with the opioid antagonist naloxone, but did exhibit normal pain behaviors in response to complete Freund's adjuvant–induced arthritis. CONCLUSION: The present results identify an animal model in which OA severity and OA pain can be studied in isolation from one another. The findings suggest that paw area and treadmill noncompliance may be useful tools to longitudinally monitor nonpainful OA development in STR/Ort mice. This will help in providing a noninvasive means of assessing new therapies to slow the progression of OA
Identifying Land Use Options for Networked Māori Owned Land Blocks to Deliver on Collective Aspirations in New Zealand
Māori (the indigenous people of New Zealand) have many opportunities and challenges to realise the potential provided by their whenua (land), wai (water) and tangata (people) to deliver to their goals and aspirations. The challenges are old and new, including environmental constraints, governance, geographic isolation, fragmented land ownership, access to finance, and lack of appropriate skills, knowledge, and networks. Extension programmes aimed at the general primary production sector have failed to attract or retain any or many Māori participants. Landowner to landowner learning built around landowner aspirations along with collective action has the potential to inform an extension approach of relevance to Māori. Shared knowledge and scale can enable the realisation of opportunities from networked primary production assets and people. A programme of work “Māori Agribusiness Extension (MABX)” is being undertaken where clusters, a grouping of Māori-owned land blocks or agribusinesses willing to collaborate or collectivise towards a common goal or agreed outcomes, are formed to enable collective learning to build confidence to implement land use change and support decision making. This paper describes the extension model being used and gives an example of one cluster
Characterizing and prognosticating chronic lymphocytic leukemia in the elderly: prospective evaluation on 455 patients treated in the United States.
BACKGROUND: Median age at diagnosis of patients with chronic lymphocytic leukemia (CLL) is \u3e 70 years. However, the majority of clinical trials do not reflect the demographics of CLL patients treated in the community. We examined treatment patterns, outcomes, and disease-related mortality in patients ≥ 75 years with CLL (E-CLL) in a real-world setting.
METHODS: The Connect® CLL registry is a multicenter, prospective observational cohort study, which enrolled 1494 adult patients between 2010-2014, at 199 US sites. Patients with CLL were enrolled within 2 months of initiating first line of therapy (LOT1) or a subsequent LOT (LOT ≥ 2). Kaplan-Meier methods were used to evaluate overall survival. CLL- and infection-related mortality were assessed using cumulative incidence functions (CIF) and cause-specific hazards. Logistic regression was used to develop a classification model.
RESULTS: A total of 455 E-CLL patients were enrolled; 259 were enrolled in LOT1 and 196 in LOT ≥ 2. E-CLL patients were more likely to receive rituximab monotherapy (19.3 vs. 8.6%; p \u3c 0.0001) and chemotherapy-alone regimens (p \u3c 0.0001) than younger patients. Overall and complete responses were lower in E-CLL patients than younger patients when given similar regimens. With a median follow-up of 3 years, CLL-related deaths were higher in E-CLL patients than younger patients in LOT1 (12.6 vs. 5.1% p = 0.0005) and LOT ≥ 2 (31.3 vs. 21.5%; p = 0.0277). Infection-related deaths were also higher in E-CLL patients than younger patients in LOT1 (7.4 vs. 2.7%; p = 0.0033) and in LOT ≥ 2 (16.2 vs. 11.2%; p = 0.0786). A prognostic score for E-CLL patients was developed: time from diagnosis to treatment \u3c 3 months, enrollment therapy other than bendamustine/rituximab, and anemia, identified patients at higher risk of inferior survival. Furthermore, higher-risk patients experienced an increased risk of CLL- or infection-related death (30.6 vs 10.3%; p = 0.0006).
CONCLUSION: CLL- and infection-related mortality are higher in CLL patients aged ≥ 75 years than younger patients, underscoring the urgent need for alternative treatment strategies for these understudied patients.
TRIAL REGISTRATION: The Connect CLL registry was registered at clinicaltrials.gov: NCT01081015 on March 4, 2010
Drivers of Human‒wildlife interactions in a co-existence area: a case study of the Ngorongoro conservation area, Tanzania
Communities in Africa bordering national parks or protected areas commonly overlap with wildlife. However, it is unclear to what degree such overlaps result in interactions with wildlife. The Ngorongoro Conservation Area (NCA) was designated a multiple land-use conservation area in 1959. Maasai and Datoga pastoralists and Hadzabe hunter-gatherers reside with protected wildlife in NCA. The study was carried out in four Maasai villages within the NCA, including Kayapus, Endulen, Meshili, and Nainokanoka. A cross-sectional study was used to assess drivers of human‒wildlife interactions using questionnaire surveys, focus group discussions, and field visits. A total of 396 households participated in the survey. The collected data were analysed using qualitative data analysis techniques and descriptive statistics such as frequencies and means. The habitat, which comprises water, pasture, shelter, and space, accounted for 100% of interactions, indicating that it is the primary driver of human‒wildlife conflict. Other driving factors for human‒wildlife interactions are the increase in wildlife, collections of firewood, domestic animals kept, and influence of community sleeping arrangements, searching for traditional medicines, and killing of lions for ritual purposes or defense. Large household sizes (36 family members) coupled with climate change have also driven and fuelled human‒wildlife interactions. Challenges identified as threatening human‒wildlife co-existence are injuries, deaths, disease transmission, and destruction of property. To mitigate human‒wildlife conflicts, the following are recommended: the increase in boarding schools coupled with the increase in enrolment of students in boarding schools or providing reliable transport, distribution of tap water, increasing food assistance to the community living in poverty, controlling population increase through reallocation the population in other areas, introducing zero-grazing, using biogas, discouraging community sleeping arrangements, i.e., humans with calves in the same house, improving record-keeping of the wildlife attacks, provisional dissemination of research findings to the community
High-temperature phase transitions in SrBi_2Ta_2O_9 film: a study by THz spectroscopy
Time-domain THz transmission experiment was performed on a film deposited on sapphire substrate. Temperatures between 300
and 923 K were investigated and complex permittivity spectra of the film were
determined. The lowest frequency optic phonon near 28 cm reveals a slow
monotonic decrease in frequency on heating with no significant anomaly near the
phase transitions. We show that the dielectric anomaly near the ferroelectric
phase transition can be explained by slowing down of a relaxational mode,
observed in the THz spectra. A second harmonic generation signal observed in a
single crystal confirms a loss of center of symmetry in the ferroelectric phase
and a presence of polar clusters in the intermediate ferroelastic phase.Comment: subm. to J. Phys.: Condens. Matte
Finite strain Landau theory of high pressure phase transformations
The properties of materials near structural phase transitions are often
successfully described in the framework of Landau theory. While the focus is
usually on phase transitions, which are induced by temperature changes
approaching a critical temperature T-c, here we will discuss structural phase
transformations driven by high hydrostatic pressure, as they are of major
importance for understanding processes in the interior of the earth. Since at
very high pressures the deformations of a material are generally very large,
one needs to apply a fully nonlinear description taking physical as well as
geometrical nonlinearities (finite strains) into account. In particular it is
necessary to retune conventional Landau theory to describe such phase
transitions. In Troster et al (2002 Phys. Rev. Lett. 88 55503) we constructed a
Landau-type free energy based on an order parameter part, an order
parameter-(finite) strain coupling and a nonlinear elastic term. This model
provides an excellent and efficient framework for the systematic study of phase
transformations for a wide range of materials up to ultrahigh pressures
Localization and Absorption of Light in 2D Composite Metal-Dielectric Films at the Percolation Threshold
We study in this paper the localization of light and the dielectric
properties of thin metal-dielectric composites at the percolation threshold and
around a resonant frequency where the conductivities of the two components are
of the same order. In particular, the effect of the loss in metallic components
are examined. To this end, such systems are modelized as random networks,
and the local field distribution as well as the effective conductivity are
determined by using two different methods for comparison: an exact resolution
of Kirchoff equations, and a real space renormalization group method. The
latter method is found to give the general behavior of the effective
conductivity but fails to determine the local field distribution. It is also
found that the localization still persists for vanishing losses. This result
seems to be in agreement with the anomalous absorption observed experimentally
for such systems.Comment: 14 page latex, 3 ps figures. submitte
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