2,987 research outputs found
A conserved metalloprotease mediates ecdysis in Caenorhabditis elegans
Molting is required for progression between larval stages
in the life cycle of nematodes. We have identified four
mutant alleles of a <i>Caenorhabditis elegans</i> metalloprotease
gene, <i>nas-37</i>, that cause incomplete ecdysis. At each molt
the cuticle fails to open sufficiently at the anterior end and
the partially shed cuticle is dragged behind the animal. The
gene is expressed in hypodermal cells 4 hours before ecdysis
during all larval stages. The <i>NAS-37</i> protein accumulates
in the anterior cuticle and is shed in the cuticle after
ecdysis. This pattern of protein accumulation places NAS-
37 in the right place and at the right time to degrade the
cuticle to facilitate ecdysis. The nas-37 gene has orthologs
in other nematode species, including parasitic nematodes,
and they undergo a similar shedding process. For example,
<i>Haemonchus contortus</i> molts by digesting a ring of cuticle
at the tip of the nose. Incubating <i>Haemonchus</i> larvae in
extracted exsheathing fluids causes a refractile ring of
digested cuticle to form at the tip of the nose. When
<i>Haemonchus</i> cuticles are incubated with purified NAS-37,
a similar refractile ring forms. NAS-37 degradation of the
<i>Haemonchus</i> cuticle suggests that the metalloproteases and
the cuticle substrates involved in exsheathment of parasitic
nematodes are conserved in free-living nematodes
Mass of a quantum 't Hooft-Polyakov monopole
The quantum mechanical mass of 't Hooft-Polyakov monopoles in the
four-dimensional Georgi-Glashow is calculated non-perturbatively using lattice
Monte Carlo simulations. This is done by imposing twisted boundary conditions
that ensure there is one unit of magnetic charge on the lattice, and measuring
the free energy difference between this ensemble and the vacuum. In the
weak-coupling limit, the results can be used to determine the quantum
correction to the classical mass, once renormalisation of couplings is taken
properly into account. The methods can also be used to study the masses at
strong coupling, i.e., near the critical point, where there are hints of a
possible electric-magnetic duality.Comment: 17 pages, 4 figures. Typos corrected, one reference adde
Impact of Guidance and Counselling Services on Studentsā Behaviour Modificatio between Selected Public Urban and Rural Secondary Schools in Rift Valley Province, Kenya
The study sought to establish and compare the impact of guidance and counselling services on studentsā behaviour modification in social and emotional adjustment in the selected public urban and rural secondary schools in Rift Valley Province, Kenya. The study adopted ex post-facto causal comparative research design The research population was form 4 students in 24 secondary schools from municipality: Eldoret, Naivasha and Nakuru,and rural/district: Uasin Gishu, Kuresoi and Molo Simple random, stratified and purposive sampling techniques were used to select 346 students, 48 school counsellors and 48 school administrators as respondents. Quantitative data was collected by administering questionnaires to students and school guidance counsellors while Qualitative data was collected through conducting an interview schedule to school administrators. Questionnaires were pilot tested before use and were found to have reliability coefficient of 0.8. The study employed one way analysis of variance (ANOVA) to test the hypothesis at 0.05 level of significance.The Statistical Packages for Social Sciences (SPSS) version 20.0.helped in data analysis. The findings of the study indicated that guidance and counselling services in secondary schools had statistically significant impact on the level of social and emotional adjustments. Rural schools indicated high level of impact of guidance and counselling services where female students expressed higher level of behaviour modification in social and emotional adjustment It was concluded that guidance and counselling services in secondary schools helps in modifying studentsā behaviour in social and emotional adjustments. Stakeholders in education sector and other youth institutions could find these findings useful in addressing secondary schools studentsā social and emotional needs. Keywords: Behaviour Modification, Guidance and Counselling Services, Social and Emotional Adjustment, Rural andUrban Secondary School
Shoshonites in southern Tibet record Late Jurassic rifting of a Tethyan intraoceanic island arc
Detailed field mapping combined with a petrologic and geochemical investigation of the Zedong terrane within the Yarlung Tsangpo suture zone provides insights to the evolution of now mostly subducted portions of Tethys during the Late Jurassic. The terrane is dominated by volcanic rocks of shoshonitic affinity, which were erupted in a submarine oceanic island arc setting. The volcanic island arc was built on a basement of oceanic crust, and the shoshonites locally overlie a thin section of pillowed island arc tholeiites and red ribbon-bedded radiolarian cherts. Geochemistry of the shoshonites suggests that their development occurred in a setting analogous to that of Late Miocene to Early Pliocene Fiji and was associated with an arc rifting. We speculate that this event may have been a far-field response to developments associated with Gondwana breakup
Magnetic monopoles from gauge theory phase transitions
Thermal fluctuations of the gauge field lead to monopole formation at the
grand unified phase transition in the early Universe, even if the transition is
merely a smooth crossover. The dependence of the produced monopole density on
various parameters is qualitatively different from theories with global
symmetries, and the monopoles have a positive correlation at short distances.
The number density of monopoles may be suppressed if the grand unified symmetry
is only restored for a short time by, for instance, nonthermal symmetry
restoration after preheating.Comment: 5 pages, updated to match the version published in PRD
(http://link.aps.org/abstract/PRD/v68/e021301) on 11 July 200
P229 PATIENT-REPORTED OUTCOMES AS A QUALITY INDICATOR OF STANDARDIZED CARE PLANS FOR TOTAL JOINT REPLACEMENT
Return to work and workplace activity limitations following total hip or knee replacement
SummaryObjectiveTotal hip (THR) and knee (TKR) replacements increasingly are performed on younger people making return to work a salient outcome. This research evaluates characteristics of individuals with early and later return to work following THR and TKR. Additionally, at work limitations pre-surgery and upon returning to work, and factors associated with work limitations were evaluated.Methods190 THR and 170 TKR of a total 931 cohort participants were eligible (i.e., working or on short-term disability pre-surgery). They completed questionnaires pre-surgery and 1, 3, 6 and 12 months post-surgery that included demographics, type of occupation, and the Workplace Activity Limitations Scale (WALS).Results166 (87%) and 144 (85%) returned to work by 12 months following THR and TKR, respectively. Early (1 month) return to work was associated with, male gender, university education, working in business, finance or administration, and low physical demand work. People with THR returned to work earlier than those with TKR. For both groups, less pain and every day functional limitations were associated with less workplace activity limitations at the time return to work.ConclusionsThe majority of individuals working prior to surgery return to work following hip or knee replacement for osteoarthritis (OA) and experience fewer limitations at work than pre-surgery. The changing workforce dynamics and trends toward surgery at younger ages mean that these are important outcomes for clinicians to assess. Additionally, this is important information for employers in understanding continued participation in employment for people with OA
Species of Bursaphelenchus Fuchs, 1937 (Nematoda: Parasitaphelenchidae) and other nematode genera associated with insects from Pinus pinaster in Portugal
Insects associated with maritime pine, Pinus pinaster, in Portugal were collected
and screened for the presence of Bursaphelenchus species. Nematodes were
identified using Internal Transcribed Spacers-Restriction Fragment Length
Polymorphism (ITS-RFLP) analysis of dauer juveniles and morphological
identification of adults that developed from dauer juveniles on fungal cultures
or on cultures in pine wood segments at 26 C. Several associations are
described: Bursaphelenchus teratospicularis and Bursaphelenchus sexdentati are
associated with Orthotomicus erosus; Bursaphelenchus tusciae, B. sexdentati and/or
Bursaphelenchus pinophilus with Hylurgus ligniperda and Bursaphelenchus hellenicus
with Tomicus piniperda, Ips sexdentatus and H. ligniperda. An unidentified
Bursaphelenchus species is vectored by Hylobius sp. The previously reported
association of Bursaphelenchus xylophilus with Monochamus galloprovincialis
was confirmed. The association of Bursaphelenchus leoni with Pityogenes sp. is
not definitively established and needs further studies for clarification.
Other nematode genera besides Bursaphelenchus were found to be associated
with the insects sampled, including two different species of Ektaphelenchus, Parasitorhabditis
sp., Parasitaphelenchus sp., Contortylenchus sp. and other unidentified
nematodes. The Ektaphelenchus species found in O. erosus is morphologically
similar to B. teratospicularis found in the same insect; adults of both the species
are found in cocoon-like structures under the elytra of the insects.
Introduction
Approximately one third of the nematodes belonging to
the order Aphelenchida Siddiqi, 1980 are associated with
insects (Poinar, 1983). These nematodes establish a variety
of associations with the insects, which may be
described as commensalism, e.g. phoresy (to the benefit
of the nematode but not affecting the insect), mutualism
(both the organisms benefit) or parasitism (nematodes
benefit at the expense of the insect) (Giblin-Davis,
2004).
Most Bursaphelenchus Fuchs, 1937 species are mycetophagous,
feeding on fungi in the galleries of bark beetles
and thu
Formation of soliton trains in Bose-Einstein condensates as a nonlinear Fresnel diffraction of matter waves
The problem of generation of atomic soliton trains in elongated Bose-Einstein
condensates is considered in framework of Whitham theory of modulations of
nonlinear waves. Complete analytical solution is presented for the case when
the initial density distribution has sharp enough boundaries. In this case the
process of soliton train formation can be viewed as a nonlinear Fresnel
diffraction of matter waves. Theoretical predictions are compared with results
of numerical simulations of one- and three-dimensional Gross-Pitaevskii
equation and with experimental data on formation of Bose-Einstein bright
solitons in cigar-shaped traps.Comment: 8 pages, 3 figure
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