To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure email@example.com
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Sitophilus zeamais is a key pest of stored grains. Its control is made, usually, using synthetic insecticides, despite their negative impacts. Botanical insecticides with fumigant/repellent properties may offer an alternative solution. This work describes the effects of Anethum graveolens, Petroselinum crispum, Foeniculum vulgare and Cuminum cyminum essential oils (EOs) and (S)-carvone, cuminaldehyde, estragole and (+)-fenchone towards adults of S. zeamais. Acute toxicity was assessed by fumigation and topical application. Repellence was evaluated by an area preference bioassay and two-choice test, using maize grains. LC50 determined by fumigation ranged from 51.8 to 535.8 mg L−1 air, with (S)-carvone being the most active. LD50 values for topical applications varied from 23 to 128 µg per adult for (S)-carvone > cuminaldehyde > A. graveolens > C. cyminum > P. crispum. All EOs/standard compounds reduced significantly the percentage of insects attracted to maize grains (65–80%) in the two-choice repellence test, whereas in the area preference bioassay RD50 varied from 1.4 to 45.2 µg cm−2, with cuminaldehyde, (S)-carvone and estragole being strongly repellents. Petroselinum crispum EO and cuminaldehyde affected the nutritional parameters relative growth rate, efficiency conversion index of ingested food and antifeeding effect, displaying antinutritional effects toward S. zeamais. In addition, P. crispum and C. cyminum EOs, as well as cuminaldehyde, showed the highest acetylcholinesterase inhibitory activity in vitro (IC50 = 185, 235 and 214.5 µg mL−1, respectively). EOs/standard compounds exhibited acute toxicity, and some treatments showed antinutritional effects towards S. zeamais. Therefore, the tested plant products might be good candidates to be considered to prevent damages caused by this pest.
The circadian disruption in shift-workers is suggested to be a risk factor to develop overweight and metabolic dysfunction. The conflicting time signals given by shifted activity, shifted food intake and exposure to light at night occurring in the shift-worker are proposed to be the cause for the loss of internal synchrony and the consequent adverse effects on body weight and metabolism. Because food elicited signals have proven to be potent entraining signals for peripheral oscillations, here we review the findings from experimental models of shift-work and verify whether they provide evidence about the causal association between shifted feeding schedules, circadian disruption and altered metabolism. We found mainly four experimental models that mimic the conditions of shift-work: protocols of forced sleep deprivation, of forced activity during the normal rest phase, exposure to light at night and shifted food timing. A big variability in the intensity and duration of the protocols was observed, which led to a diversity of effects. A common result was the disruption of temporal patterns of activity; however, not all studies explored the temporal patterns of food intake. According to studies that evaluate time of food intake as an experimental model of shift-work and studies that evaluate shifted food consumption, time of food intake may be a determining factor for the loss of balance at the circadian and metabolic level.
Predicting recurrent Clostridium difficile infection (rCDI) remains difficult. METHODS. We employed a retrospective cohort design. Granular electronic medical record (EMR) data had been collected from patients hospitalized at 21 Kaiser Permanente Northern California hospitals. The derivation dataset (2007–2013) included data from 9,386 patients who experienced incident CDI (iCDI) and 1,311 who experienced their first CDI recurrences (rCDI). The validation dataset (2014) included data from 1,865 patients who experienced incident CDI and 144 who experienced rCDI. Using multiple techniques, including machine learning, we evaluated more than 150 potential predictors. Our final analyses evaluated 3 models with varying degrees of complexity and 1 previously published model.
Despite having a large multicenter cohort and access to granular EMR data (eg, vital signs, and laboratory test results), none of the models discriminated well (c statistics, 0.591–0.605), had good calibration, or had good explanatory power.
Our ability to predict rCDI remains limited. Given currently available EMR technology, improvements in prediction will require incorporating new variables because currently available data elements lack adequate explanatory power.
This paper introduces GLINTS, a graphical tool for exploring variant narrowing computations in Maude. The most recent version of Maude, version 2.7.1, provides quite sophisticated unification features, including order-sorted equational unification for convergent theories modulo axioms such as associativity, commutativity, and identity. This novel equational unification relies on built-in generation of the set of variants of a term t, i.e., the canonical form of tσ for a computed substitution σ. Variant generation relies on a novel narrowing strategy called folding variant narrowing that opens up new applications in formal reasoning, theorem proving, testing, protocol analysis, and model checking, especially when the theory satisfies the finite variant property, i.e., there is a finite number of most general variants for every term in the theory. However, variant narrowing computations can be extremely involved and are simply presented in text format by Maude, often being too heavy to be debugged or even understood. The GLINTS system provides support for (i) determining whether a given theory satisfies the finite variant property, (ii) thoroughly exploring variant narrowing computations, (iii) automatic checking of node embedding and closedness modulo axioms, and (iv) querying and inspecting selected parts of the variant trees.
Positive Deviance (PD) is a process to achieve a social and cultural change. This strategy has been used for the control of methicillin-resistant Staphylococcus aureus (MRSA) infection in some health institutions in the United States, but has rarely been adopted in institutions from developing countries where resources are limited. We describe our experience of PD in the control of healthcare-associated infections (HAIs) due to MRSA in a Colombian hospital with the aim of reducing HAI rates through a cultural change in processes. A time-series study was conducted based on the MRSA-HAI rate and the number of months with zero MRSA infections before and after application of PD (2001–2012). On comparing the pre-intervention and intervention periods, the mean overall rates of MRSA-HAI was 0·62 and 0·36, respectively (P = 0·0005); the number of months with zero MRSA-HAIs were 3/70 and 12/74 (odds ratio 0·264, 95% confidence interval 0·078–0·897); the percentage of MRSA-HAIs was 53·2% and 41·0%. These results are consistent with other published data. Implementation of PD was associated with a significant reduction of MRSA-HAIs, it did not involve high costs and the changes have been lasting.
Substantial research has been completed examining the impact of carbohydrate (CHO) intake on endurance exercise, whereas its role in resistance-based exercise performance, adaptation and cell signalling has yet to be fully characterised. This empirical shortcoming has precluded the ability to establish specific CHO recommendations for resistance exercise. This results in recommendations largely stemming from findings based on endurance exercise and/or anecdotal evidence despite the distinct energetic demands and molecular responses mediating adaptation from endurance- and resistance-based exercise. Moreover, the topic of CHO and exercise has become one of polarising nature with divergent views – some substantiated, others lacking evidence. Current literature suggests a moderately high daily CHO intake (3–7 g/kg per d) for resistance training, which is thought to prevent glycogen depletion and facilitate performance and adaptation. However, contemporary investigation, along with an emerging understanding of the molecular underpinnings of resistance exercise adaptation, may suggest that such an intake may not be necessary. In addition to the low likelihood of true glycogen depletion occurring in response to resistance exercise, a diet restrictive in CHO may not be detrimental to acute resistance exercise performance or the cellular signalling activity responsible for adaptation, even when muscle glycogen stores are reduced. Current evidence suggests that signalling of the mammalian target of rapamycin complex 1, the key regulatory kinase for gene translation (protein synthesis), is unaffected by CHO restriction or low muscular glycogen concentrations. Such findings may call into question the current view and subsequent recommendations of CHO intake with regard to resistance-based exercise.
Comprehensive psychiatric rehabilitation programs in Latin America have been designed across several countries in the region without yet achieving full implementation. Facing an increasing burden of disease due to mental disorders, including alcohol and substance use disorders, the region has responded unevenly to the challenge. Moreover, low priority for mental health in national policies and insufficient funding for mental health services are common barriers for the much-needed mental health services reforms. Reestablishing a primary care community-based model of care has been a shared aspiration for most countries during the last two decades. Comprehensive models of psychiatric rehabilitation developed predominantly in high-income countries need to be culturally adapted to local contexts, while strengthening health systems research will provide evidence on the efficiency of locally designed interventions and on the critical milestones to succeed in the scaling up strategies. Increasing participation of patients and their families in the mental health delivery system is another key factor in order to ensure comprehensive patient-centred psychosocial rehabilitation programs in Latin America.
Considerable efforts have been dedicated to developing strategies to prevent and treat recurrent Clostridium difficile infection (rCDI); however, evidence of the impact of rCDI on patient healthcare utilization and outcomes is limited.
To compare healthcare utilization and 1-year mortality among adults who had rCDI, nonrecurrent CDI, or no CDI.
We performed a nested case-control study among adult Kaiser Foundation Health Plan members from September 1, 2001, through December 31, 2013. We identified CDI through the presence of a positive laboratory test result and divided patients into 3 groups: patients with rCDI, defined as CDI in the 14–57 days after initial CDI; patients with nonrecurrent CDI; and patients who never had CDI. We conducted 3 matched comparisons: (1) rCDI vs no CDI; (2) rCDI vs nonrecurrent CDI; (3) nonrecurrent CDI vs no CDI. We followed patients for 1 year and compared healthcare utilization between groups, after matching patients on age, sex, and comorbidity.
We found that patients with rCDI consistently have substantially higher levels of healthcare utilization in various settings and greater 1-year mortality risk than both patients who had nonrecurrent CDI and patients who never had CDI.
Patients who develop an initial CDI are generally characterized by excess underlying, severe illness and utilization. However, patients with rCDI experience even greater adverse consequences of their disease than patients who do not experience rCDI. Our results further support the need for continued emphasis on identifying and using novel approaches to prevent and treat rCDI.
The study determined the performance of equations to predict enteric methane (CH4) from beef cattle fed forage- and grain-based diets. Many equations are available to predict CH4 from beef cattle and the predictions vary substantially among equations. The aims were to (1) construct a database of CH4 emissions for beef cattle from published literature, and (2) identify the most precise and accurate extant CH4 prediction models for beef cattle fed diets varying in forage content. The database was comprised of treatment means of CH4 production from in vivo beef studies published from 2000 to 2015. Criteria to include data in the database were as follows: animal description, intakes, diet composition and CH4 production. In all, 54 published equations that predict CH4 production from diet composition were evaluated. Precision and accuracy of the equations were evaluated using the concordance correlation coefficient (rc), root mean square prediction error (RMSPE), model efficiency and analysis of errors. Equations were ranked using a combined index of the various statistical assessments based on principal component analysis. The final database contained 53 studies and 207 treatment means that were divided into two data sets: diets containing ⩾400 g/kg dry matter (DM) forage (n=116) and diets containing ⩽200 g/kg DM forage (n=42). Diets containing between ⩽400 and ⩾200 g/kg DM forage were not included in the analysis because of their limited numbers (n=6). Outliers, treatment means where feed was fed restrictively and diets with CH4 mitigation additives were omitted (n=43). Using the high-forage dataset the best-fit equations were the International Panel on Climate Change Tier 2 method, 3 equations for steers that considered gross energy intake (GEI) and body weight and an equation that considered dry matter intake and starch:neutral detergent fiber with rc ranging from 0.60 to 0.73 and RMSPE from 35.6 to 45.9 g/day. For the high-grain diets, the 5 best-fit equations considered intakes of metabolisable energy, cellulose, hemicellulose and fat, or for steers GEI and body weight, with rc ranging from 0.35 to 0.52 and RMSPE from 47.4 to 62.9 g/day. Ranking of extant CH4 prediction equations for their accuracy and precision differed with forage content of the diet. When used for cattle fed high-grain diets, extant CH4 prediction models were generally imprecise and lacked accuracy.
As obesity and metabolic diseases rise, there is need to investigate physiological and behavioural aspects associated with their development. Circadian rhythms have a profound influence on metabolic processes, as they prepare the body to optimise energy use and storage. Moreover, food-related signals confer temporal order to organs involved in metabolic regulation. Therefore food intake should be synchronised with the suprachiasmatic nucleus (SCN) to elaborate efficient responses to environmental challenges. Human studies suggest that a loss of synchrony between mealtime and the SCN promotes obesity and metabolic disturbances. Animal research using different paradigms has been performed to characterise the effects of timing of food intake on metabolic profiles. Therefore the purpose of the present review is to critically examine the evidence of animal studies, to provide a state of the art on metabolic findings and to assess whether the paradigms used in rodent models give the evidence to support a ‘best time’ for food intake. First we analyse and compare the current findings of studies where mealtime has been shifted out of phase from the light–dark cycle. Then, we analyse studies restricting meal times to different moments within the active period. So far animal studies correlate well with human studies, demonstrating that restricting food intake to the active phase limits metabolic disturbances produced by high-energy diets and that eating during the inactive/sleep phase leads to a worse metabolic outcome. Based on the latter we discuss the missing elements and possible mechanisms leading to the metabolic consequences, as these are still lacking.
Mental health research funding priorities in high-income countries must balance longer-term investment in identifying neurobiological mechanisms of disease with shorter-term funding of novel prevention and treatment strategies to alleviate the current burden of mental illness. Prioritising one area of science over others risks reduced returns on the entire scientific portfolio.
Studies on microbial biohydrogenation of fatty acids in the rumen are of importance as this process lowers the availability of nutritionally beneficial unsaturated fatty acids for incorporation into meat and milk but also might result in the accumulation of biologically active intermediates. The impact was studied of adsorption of 22:6n-3 (DHA) to particulate material on its disappearance during 24 h in vitro batch incubations with rumen inoculum. Four adsorbants were used in two doses (1 and 5 mg/ml of mucin, gum arabic, bentonite or silicic acid). In addition, the distribution of 22:6n-3 in the pellet and supernatant of diluted rumen fluid was measured. Bentonite and silicic acid did not alter the distribution of 22:6n-3 between pellet and supernatant nor increased the disappearance of 22:6n-3 during the incubation. Both mucin and gum arabic increased the recovery of 22:6n-3 in the supernatant, indicating that these compounds lowered the adsorption of the fatty acid to ruminal particles. This was associated with an increased disappearance of 22:6n-3, when initial 22:6n-3 was 0.06 or 0.10 mg/ml, and an increased formation of 22:0, when initial 22:6n-3 was 0.02 mg/ml, during the 24 h batch culture experiment. Addition of gum arabic to pure cultures of Butyrivibrio fibrisolvens or Butyrivibrio proteoclasticus did not negate the inhibitory effect of 22:6n-3 on growth. As both mucin and gum arabic provide fermentable substrate for ruminal bacteria, an additional experiment was performed in which mucin and gum arabic were replaced by equal amounts of starch, cellulose or xylan. No differences in disappearance of 22:6n-3 were observed, suggesting that the stimulatory effect of mucin and gum arabic on disappearance of 22:6n-3 most probably is not due to provision of an alternative site of adsorption but related to stimulation of bacterial growth. A relatively high proportion of 22:6n-3 can be reduced to 22:0 provided the initial concentration is low.
The process of selecting cabinet ministers often takes place behind closed doors, including weighing the need to balance or manage factions within the president's party and/or coalition partners; addressing demands for diversity in the cabinet, such as appointment of women or other historically underrepresented groups; sending signals about the administration's policy agenda; and enabling the president to have people he or she trusts close at hand. On the other hand, ministerial exits are usually less private affairs. In some cases they come after weeks of public or congressional scrutiny and criticism of ministers for policy failures or follow extended speculation about who will lose their seat when the president reshuffles the cabinet. Some ministers depart to pursue lucrative private-sector opportunities. Other ministers switch posts but stay in government. How ministers exit can have implications for the administration since a president who is frequently forced to shuffle the cabinet or sack ministers looks ineffective, and comparisons to rats and sinking ships are difficult to avoid in the wake of excessive changes. At the same time, an administration with zero turnover may also not be healthy, as it would suggest that presidents are staidly bound to their initial course of action and unable (or unwilling) to adapt to changing circumstances.
Dientamoeba fragilis is an inhabitant of human gastrointestinal tract with a worldwide distribution. The first description considered this protozoan a rare and harmless commensal, since then it has struggled to gain recognition as a pathogen. Commercial multiplex real-time PCR was used to detect D. fragilis in fecal samples from hospitalized children (⩽18 years) with acute gastrointestinal disease, admitted to two hospitals of Lisbon area, with different demographic characteristics. A total of 176 children were studied, 103 (58·5%) male, 144 (81·8%) children between 0 and 5 years and 32 (18·2%) above 6 years old. The overall protozoa frequency considering the four tested microorganisms were 8·5% (15/176), and the most frequently found protozoan was D. fragilis, 6·3% (11/176). Dientamoeba fragilis frequency was higher among older children (21·9%), than younger children (2·8%), and greater in boys (6·8%) than in girls (5·5%). All positive children presented with diarrhoea associated with vomiting, fever and abdominal pain. Infection was associated with the age of children (P < 0·001), school attendance (P = 0·002) and consumption of certain foods (P = 0·014), e.g. cakes with crème and ham. The frequency of diantamoebiasis found in a cohort of hospitalized Portuguese children, with acute gastrointestinal disease, could be considered a very high value when compared with the protozoan frequency normally associated with this pathology.
Miconia chartacea is a widely distributed tree in Brazil, occurring at altitudes ranging from 300 m to 1900 m in the Caatinga, Cerrado and Atlantic Forest biomes. In this work we attempted to classify M. chartacea seeds regarding their behaviour during storage and their germination syndrome and to determine, from a storage test in Cerrado soil and laboratory conditions in situ and ex situ, the longevity of seeds, as well as the capacity of the species to form a soil seed bank. The results suggested that M. chartacea seeds form a transient soil seed bank in the Cerrado and can be classified as orthodox in terms of storage behaviour, although the seeds are dispersed with a relatively high water content. The life span of seeds was favoured in soil-stored seeds in comparison with dry storage at 25°C, whereas storage at low temperatures prevented a decrease of the seed's germinability with storage time (330 d). M. chartacea seeds are dispersed during the dry season and germinate during the next rainy season, which can be classified as an intermediate–dry germination syndrome. Seeds of this species are dispersed in the Cerrado when temperatures and soil moisture are relatively low, which favours the formation of a soil seed bank, considering that the seeds tolerate desiccation and their longevity is favoured by low temperatures. A transient seed bank type is favoured by the loss of viability in storage at warm temperatures linked to the rainy season, and the predictable seasonal variations in climate in the region, with germination being restricted to the beginning of the rainy season.
In Chile, while dog rabies has decreased markedly over the last 30 years, bat rabies is still reported frequently. In order to shed new light on the spatiotemporal trends of these reports, we analysed active and passive data from years 1985 and 2012, which included 61 076 samples from 289 counties of Chile. We found that from 1994 to 2012, more than 15 000 bat samples were submitted for diagnostics through passive surveillance, 9·5% of which tested positive for rabies. By contrast, the prevalence of infection was only ~0·4% among the nearly 12 000 bat samples submitted through active surveillance. We found that the prevalence of dog rabies dropped steadily over the same period, with just a single confirmed case since 1998. None of the 928 samples from wild animals, other than bats, were positive for rabies. Although there has been only one confirmed case of human rabies in Chile since 1985, and a single confirmed case in a dog since 1998, bats remain a reservoir for rabies viruses. While active surveillance indicates that rabies prevalence is low in bat colonies, the high proportion of positive bats submitted through passive surveillance is a concern. To prevent human rabies, local public health agencies should increase research on the basic ecology of bats and the role of stray dogs and cats as potential rabies amplifiers.
The dye-sensitized solar cells (DSSC) are a technological and economical alternative to conventional p-n junction solar cells. The DSSC is composed of a transparent conducting electrode (SnO2:F) coated by a porous, nanocrystalline film of n-ZnO to which dye molecules are attached, an organic electrolyte containing a reduction-oxidation couple, and finally a counter-electrode (glass/SnO2:F) coated by a thin film of platinum. The most efficient dyes for DSSCs are based on Ruthenium polypyridyl complexes, related to the high absorption coefficient in the entire visible range and the efficient injection of electrons into the conduction band of ZnO. However, the ruthenium polypyridyl complex contains a heavy metal of relatively high cost, and synthetic routes are complicated with low yields. Moreover, natural dyes in addition to their availability, are cost-effective, non-toxic and biodegradable materials, and can be extracted by simple procedures. In this paper we report the extraction of natural dyes from the stems of mangrove (D1) and tinto (D2) trees as well as from walnut (D3) shell. First, it was necessary to dehydrate the materials, after which extraction was performed using ethanol, water and sodium hydroxide solution. The dyes were characterized using UV-visible and infrared spectroscopy. The analysis of the infrared spectra shows an intense and broad band related to OH bond stretching vibration at 3393, 3442 and 3390 cm-1 for the mangrove tree, tinto tree and walnut shell, respectively. At 1051, 1123 and 1050 cm-1, there was a very strong absorption due to the stretching vibration of CO group, for the mangrove tree, tinto tree and walnut shell, respectively. These results indicate that the functional group for bonding to the ZnO is -OH for these dyes. The results of the U-Vis spectroscopy show that the strongest absorption in the visible region is provided by dyes of the tinto and mangrove trees. The current - voltage curve of a preliminary ZnO-DSSC sensitized with the natural dye of the mangrove tree bark is presented.
Positron Beam Analysis was for the first time performed in combination with a four-point bending stage. Applications of this novel technique on PVD TiN (5 m thick), WC:H (2.5 m) and CrN (1.5 m m) layers on tool steel, low carbon steel and stainless steel substrates are discussed. It appeared from PBA results that for these systems the coatings did not fail by delamination during bending. SEM confirmed that there was no decohesion but instead, cracking of the coatings was observed. In order to weaken the interface and quantify adhesion properties we propose to induce blistering based on localised gas implantation.
The influence of controlled potential conditions on the structure and phases of BaTiO3 films grown on titanium by the hydrothermal-electrochemical method was studied. The experiments were conducted using a three electrode high pressure electrochemical cell in a 0.2 M Ba(OH)2 electrolyte at 150 °C. The spontaneous initial nucleation linked to pure hydrothermal BaTiO3 formation was inhibited by cathodically protecting the titanium electrode since its immersion in the electrolyte. The application of initial nucleation pulses of varying cathodic potentials affected the grain size of the deposit. The growth of tetragonal BaTiO3 was achieved combining the initial inhibition of the pure hydrothermal growth, followed by nucleation under controlled potentiostatic conditions.
We have studied the growth and the physical properties of LiCoO2 films as a function of formation conditions, i.e., substrate temperature and partial oxygen pressure. These films were grown on various substrates by the laser ablation technique using a Nd:YAG laser at 100 MW/cm2 power density. LiCoO2 films were characterized by XRD, SEM, and vibrational spectroscopy. The synthesized compounds show high homogeneity in composition and in particle dimension. The main advantage of this method is the less time needed for the reaction to occur completely. Raman scattering spectroscopy provides information on the local environment of cations.