202 research outputs found
Effects of Livestock Grazing on Honey Production in a Mediterranean Rangeland Ecosystem
Livestock husbandry has played an integral role for human societies in the Mediterranean Basin.
While ruminant grazing traditionally comprised part of diverse agrosilvopastoral systems, in
recent decades it has experienced substantial intensification in Mediterranean countries due to
European Union subsidies and production for international markets. Apiculture has also played
an important role in rural Mediterranean livelihoods for millennia, and is important globally both
for apicultural products and crop pollination. Honeybees have faced worldwide losses in recent
decades, along with a decline of floral resources, although the drivers of these changes are not
well understood. The aim of this study is to (1) evaluate the impact of livestock grazing on
Mediterranean vegetation structure and floral resources; (2) determine the relationship, between
grazing intensity and the productivity of managed honeybee hives, and; (3) determine the
economic effect, if any, that overgrazing has on apicultural activities in the region.
Methods. I measured vegetation condition and floral resources across a broad range of livestock
grazing intensities in a Mediterranean phryganic ecosystem on the islands of Naxos and Paros in
the Aegean Sea (Greece). 14 study plots were surveyed, and the vegetation metrics of canopy
gap, basal gap, vegetation height, plant species richness, spring flower coverage, thyme flower
coverage, and thyme bush coverage were measured. As a proxy for grazing intensity, I used
stocking rates, as well as biomass removed by grazers, quantified as the amount of ruminant
dung collected along standardized transects. I monitored beehive productivity by weighing
beehives every 10 to 14 days over the course of the summer flowering season. I established
transects in the vicinity of the beehives, and repeated the same vegetation measurements used in
the 14 study plots to determine vegetation condition around each beehive site. Mixed models
were utilized in order to determine the relationship between beehive productivity and
surrounding vegetation characteristics. In addition, I conducted surveys with a majority of
beekeepers on each island to determine potential economic effects of grazing intensity on
apiculture.
Results. I found grazing to significantly impact vegetation cover and floral resources. Canopy
gap and basal gap sizes were positively correlated with grazing intensity, while plant species
richness was negatively associated with grazing intensity. Standing vegetation biomass
decreased with increased grazing intensity, whether quantified as stocking rate or amount of
plant matter consumed. Spring flower coverage also decreased with amount of plant matter
consumed by livestock. However, cover of Conehead thyme (Coridothymus capitatus), the most
important apicultural plant in the region, and a chemically defended taxon, actually benefitted
from light to intermediate grazing conditions and followed a hump-shaped curve peaking at
intermediate stocking rates. As a result, progressive increases in stocking rate had mixed effects
on floral resources, leading to an overall reduction in general flower cover and diversity, while
simultaneously leading to denser populations of thyme. Mixed models revealed that beehive
productivity during the main honey-producing period was positively associated with increased
thyme flower area, stocking rate, thyme bush area, canopy gap, and basal gap (in decreasing
order of importance). Interviews with beekeepers also revealed that grazing intensity was
positively correlated with the need for higher amounts of supplemental bee food outside the short
summer thyme season, elevated antiparasitic drug expenditures, as well as increased total costs
(including feed, drug, labor and hive replacement expenditures). These expenses erased higher
iii
income from elevated thyme honey production in grazed areas. Notably, the surveys showed no
correlation between grazing intensity and net profits. As a matter of fact, comparison of the
economic apiculture models on the neighboring islands of Naxos (mostly heavily grazed) and
Paros (mostly ungrazed) revealed that beekeeping operations on Paros, by virtue of their lower
costs, generated higher overall returns, despite producing less honey.
Conclusions. This study highlights the central importance of C. capitatus, a prolific nectarproducing
species, for honey production in the Aegean. Despite the fact that C. capitatus benefits
from low to intermediate levels of grazing, due to competitive release, livestock husbandry has
largely negative effects on apiculture in the Aegean. By extending the scope of this study beyond
the traditionally considered first order metrics (honey production) to include additional factors
(previously externalized beehive maintenance costs), I show any increases in thyme honey
production in grazed regions are negated by concomitant increased costs for bee food, drugs,
labor and elevated beehive replacement rates. Thus my data suggest that light levels of grazing
are best suited to maximize economic returns from apiculture in the Aegean Sea region.Master of ScienceNatural Resources and EnvironmentUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/123033/1/Scott BrentonThesis Final.pd
Memoirs of a Chiropterologist
Environmental Writing and Great Lakes LiteratureI caught lizards with my professor all morning, until the bright Aegean sun became too
hot for them to be active. As my professor took measurements and recorded data of the lizards
we had caught, I took a nap on the forest floor. My own level of activity that day was in synch
with that of the lizards, just as it had been with that of the bats all summer long in Crete. This
was a new, more specific type of connection with nature that I had never before realized until
that moment, that summer. I was no longer working for the credits I would get the next fall for
my internship, which had nothing to do with lizards. I had not even graduated, yet my
environment major had already provided me with the means to go where I want, and do what I
want in the world. As I lay there in the bed of pine needles on the forest floor of the island of
Piperi, I for once in my life felt free of the need to hope or fear anything, confident that I had
found my place in the world of science.http://deepblue.lib.umich.edu/bitstream/2027.42/64860/1/Brenton_Scott_2009.pd
Assessment of the cross-protective capability of recombinant capsid proteins derived from pig, rat, and avian hepatitis E viruses (HEV) against challenge with a genotype 3 HEV in pigs
Hepatitis E virus (HEV), the causative agent of hepatitis E, is primarily transmitted via the fecal-oral route through contaminated water supplies, although many sporadic cases of hepatitis E are transmitted zoonotically via direct contact with infected animals or consumption of contaminated animal meats. Genotypes 3 and 4 HEV are zoonotic and infect humans and other animal species, whereas genotypes 1 and 2 HEV are restricted to humans. There exists a single serotype of HEV, although the cross-protective ability among the animal HEV strains is unknown. Thus, in this study we expressed and characterized N-terminal truncated ORF2 capsid antigens derived from swine, rat, and avian HEV strains and evaluated their cross-protective ability in a pig challenge model. Thirty, specific-pathogen-free, pigs were divided into 5 groups of 6 pigs each, and each group of pigs were vaccinated with 200 Β΅g of swine HEV, rat HEV, or avian HEV ORF2 antigen or PBS buffer (2 groups) as positive and negative control groups. After a booster dose immunization at 2 weeks post-vaccination, the vaccinated animals all seroconverted to IgG anti-HEV. At 4 weeks post-vaccination, the animals were intravenously challenged with a genotype 3 mammalian HEV, and necropsied at 4 weeks post-challenge. Viremia, fecal virus shedding, and liver histological lesions were compared to assess the protective and cross-protective abilities of these antigens against HEV challenge in pigs. The results indicated that pigs vaccinated with truncated recombinant capsid antigens derived from three animal strains of HEV induced a strong IgG anti-HEV response in vaccinated pigs, but these antigens confer only partial cross-protection against a genotype 3 mammalian HEV. The results have important implications for the efficacy of current vaccines and for future vaccine development, especially against the novel zoonotic animal strains of HEV
Developing a simulation safety policy for translational simulation programs in healthcare
Healthcare simulation may present risks to safety, especially when delivered βin situββin real clinical environmentsβwhen lines between simulated and real practice may be blurred. We felt compelled to develop a simulation safety policy (SSP) after reading reports of adverse events in the healthcare simulation literature, editorials highlighting these safety risks, and reflecting on our own experience as a busy translational simulation service in a large healthcare institution. The process for development of a comprehensive SSP for translational simulation programs is unclear. Personal correspondence with leaders of simulation programs like our own revealed a piecemeal approach in most institutions. In this article, we describe the process we used to develop the simulation safety policy at our health service, and crystalize principles that may provide guidance to simulation programs with similar challenges. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s41077-022-00200-9
An intramolecular t-SNARE complex functions in vivo without the syntaxin NH2-terminal regulatory domain
Membrane fusion in the secretory pathway is mediated by SNAREs (located on the vesicle membrane [v-SNARE] and the target membrane [t-SNARE]). In all cases examined, t-SNARE function is provided as a three-helix bundle complex containing three βΌ70βamino acid SNARE motifs. One SNARE motif is provided by a syntaxin family member (the t-SNARE heavy chain), and the other two helices are contributed by additional t-SNARE light chains. The syntaxin family is the most conformationally dynamic group of SNAREs and appears to be the major focus of SNARE regulation. An NH2-terminal region of plasma membrane syntaxins has been assigned as a negative regulatory element in vitro. This region is absolutely required for syntaxin function in vivo. We now show that the required function of the NH2-terminal regulatory domain (NRD) of the yeast plasma membrane syntaxin, Sso1p, can be circumvented when t-SNARE complex formation is made intramolecular. Our results suggest that the NRD is required for efficient t-SNARE complex formation and does not recruit necessary scaffolding factors
Wave energy localization by self-focusing in large molecular structures: a damped stochastic discrete nonlinear Schroedinger equation model
Wave self-focusing in molecular systems subject to thermal effects, such as
thin molecular films and long biomolecules, can be modeled by stochastic
versions of the Discrete Self-Trapping equation of Eilbeck, Lomdahl and Scott,
and this can be approximated by continuum limits in the form of stochastic
nonlinear Schroedinger equations.
Previous studies directed at the SNLS approximations have indicated that the
self-focusing of wave energy to highly localized states can be inhibited by
phase noise (modeling thermal effects) and can be restored by phase damping
(modeling heat radiation).
We show that the continuum limit is probably ill-posed in the presence of
spatially uncorrelated noise, at least with little or no damping, so that
discrete models need to be addressed directly. Also, as has been noted by other
authors, omission of damping produces highly unphysical results.
Numerical results are presented for the first time for the discrete models
including the highly nonlinear damping term, and new numerical methods are
introduced for this purpose. Previous conjectures are in general confirmed, and
the damping is shown to strongly stabilize the highly localized states of the
discrete models. It appears that the previously noted inhibition of nonlinear
wave phenomena by noise is an artifact of modeling that includes the effects of
heat, but not of heat loss.Comment: 22 pages, 13 figures, revision of talk at FPU+50 conference in Rouen,
June 200
Translational simulation for rapid transformation of health services, using the example of the COVID-19 pandemic preparation
Sec1p directly stimulates SNARE-mediated membrane fusion in vitro
Sec1 proteins are critical players in membrane trafficking, yet their precise role remains unknown. We have examined the role of Sec1p in the regulation of post-Golgi secretion in Saccharomyces cerevisiae. Indirect immunofluorescence shows that endogenous Sec1p is found primarily at the bud neck in newly budded cells and in patches broadly distributed within the plasma membrane in unbudded cells. Recombinant Sec1p binds strongly to the t-SNARE complex (Sso1p/Sec9c) as well as to the fully assembled ternary SNARE complex (Sso1p/Sec9c;Snc2p), but also binds weakly to free Sso1p. We used recombinant Sec1p to test Sec1p function using a well-characterized SNARE-mediated membrane fusion assay. The addition of Sec1p to a traditional in vitro fusion assay moderately stimulates fusion; however, when Sec1p is allowed to bind to SNAREs before reconstitution, significantly more Sec1p binding is detected and fusion is stimulated in a concentration-dependent manner. These data strongly argue that Sec1p directly stimulates SNARE-mediated membrane fusion
Mii-vitaliSe: a pilot randomised controlled trial of a home gaming system (Nintendo Wii) to increase activity levels, vitality and well-being in people with multiple sclerosis.
OBJECTIVES: While the health and well-being benefits of physical activity are recognised, people with multiple sclerosis (MS) often face greater barriers than the general population. The Nintendo Wii potentially offers a fun, convenient way of overcoming some of these. The aim was to test the feasibility of conducting a definitive trial of the effectiveness and cost-effectiveness of Mii-vitaliSe; a home-based, physiotherapist-supported Nintendo Wii intervention. DESIGN: A single-centre wait-list randomised controlled study. SETTING: MS service in secondary care. PARTICIPANTS: Ambulatory, relatively inactive people with clinically confirmed MS. INTERVENTION: Thirty participants were randomised to receive Mii-vitaliSe either immediately (for 12 months) or after a 6-month wait (for 6 months). Mii-vitaliSe consisted of two supervised Nintendo Wii familiarisation sessions in the hospital followed by home use (Wii Sports, Sports Resort and Fit Plus software) with physiotherapist support and personalised resources. OUTCOMES: Included self-reported physical activity levels, quality of life, mood, self-efficacy, fatigue and assessments of balance, gait, mobility and hand dexterity at baseline, 6 and 12 months. Interviews (n=25) explored participants' experiences and, at study end, the two Mii-vitaliSe facilitators' experiences of intervention delivery (main qualitative findings reported separately). RESULTS: Mean (SD) age was 49.3 (8.7) years, 90% female, with 47% diagnosed with MS <6 years ago and 60% new to active gaming. The recruitment rate was 31% (95% CI 20% to 44%). Outcome data were available for 29 (97%) at 6 months and 28 (93%) at 12 months. No serious adverse events were reported during the study. Qualitative data indicated that Mii-vitaliSe was well-received. Mean Wii use across both groups over the initial 6-month intervention period was twice a week for 27βmin/day. Mean cost of delivering Mii-vitaliSe was Β£684 per person. DISCUSSION: Mii-vitaliSe appears acceptable and a future trial feasible and warranted. These findings will inform its design. TRIAL REGISTRATION: ISRCTN49286846
The American Association for the Surgery of Trauma renal injury grading scale: Implications of the 2018 revisions for injury reclassification and predicting bleeding interventions.
BackgroundIn 2018, the American Association for the Surgery of Trauma (AAST) published revisions to the renal injury grading system to reflect the increased reliance on computed tomography scans and non-operative management of high-grade renal trauma (HGRT). We aimed to evaluate how these revisions will change the grading of HGRT and if it outperforms the original 1989 grading in predicting bleeding control interventions.MethodsData on HGRT were collected from 14 Level-1 trauma centers from 2014 to 2017. Patients with initial computed tomography scans were included. Two radiologists reviewed the scans to regrade the injuries according to the 1989 and 2018 AAST grading systems. Descriptive statistics were used to assess grade reclassifications. Mixed-effect multivariable logistic regression was used to measure the predictive ability of each grading system. The areas under the curves were compared.ResultsOf the 322 injuries included, 27.0% were upgraded, 3.4% were downgraded, and 69.5% remained unchanged. Of the injuries graded as III or lower using the 1989 AAST, 33.5% were upgraded to grade IV using the 2018 AAST. Of the grade V injuries, 58.8% were downgraded using the 2018 AAST. There was no statistically significant difference in the overall areas under the curves between the 2018 and 1989 AAST grading system for predicting bleeding interventions (0.72 vs. 0.68, p = 0.34).ConclusionAbout one third of the injuries previously classified as grade III will be upgraded to grade IV using the 2018 AAST, which adds to the heterogeneity of grade IV injuries. Although the 2018 AAST grading provides more anatomic details on injury patterns and includes important radiologic findings, it did not outperform the 1989 AAST grading in predicting bleeding interventions.Level of evidencePrognostic and Epidemiological Study, level III
- β¦