How long do people stick to a diet resolution? A digital epidemiological estimation of weight loss diet persistence.

OBJECTIVE: To use Internet search data to compare duration of compliance for various diets. DESIGN: Using a passive surveillance digital epidemiological approach, we estimated the average duration of diet compliance by examining monthly Internet searches for recipes related to popular diets. We fit a mathematical model to these data to estimate the time spent on a diet by new January dieters (NJD) and to estimate the percentage of dieters dropping out during the American winter holiday season between Thanksgiving and the end of December. SETTING: Internet searches in the USA for recipes related to popular diets over a 15-year period from 2004 to 2019. PARTICIPANTS: Individuals in the USA performing Internet searches for recipes related to popular diets. RESULTS: All diets exhibited significant seasonality in recipe-related Internet searches, with sharp spikes every January followed by a decline in the number of searches and a further decline in the winter holiday season. The Paleo diet had the longest average compliance times among NJD (5.32 ± 0.68 weeks) and the lowest dropout during the winter holiday season (only 14 ± 3 % dropping out in December). The South Beach diet had the shortest compliance time among NJD (3.12 ± 0.64 weeks) and the highest dropout during the holiday season (33 ± 7 % dropping out in December). CONCLUSIONS: The current study is the first of its kind to use passive surveillance data to compare the duration of adherence with different diets and underscores the potential usefulness of digital epidemiological approaches to understanding health behaviours.

Quantifying the relative effects of environmental and direct transmission of norovirus.

Norovirus is a common cause of outbreaks of acute gastroenteritis in health- and child-care settings, with serial outbreaks also frequently observed aboard cruise ships. The relative contributions of environmental and direct person-to-person transmission of norovirus have hitherto not been quantified. We employ a novel mathematical model of norovirus transmission, and fit the model to daily incidence data from a major norovirus outbreak on a cruise ship, and examine the relative efficacy of potential control strategies aimed at reducing environmental and/or direct transmission. The reproduction number for environmental and direct transmission combined is [Formula: see text] [6.1,9.5], and of environmental transmission alone is [Formula: see text] [0.9,2.6]. Direct transmission is overwhelmingly due to passenger-to-passenger contacts, but crew can act as a reservoir of infection from cruise to cruise. This is the first quantification of the relative roles of environmental and direct transmission of norovirus. While environmental transmission has the potential to maintain a sustained series of outbreaks aboard a cruise ship in the absence of strict sanitation practices, direct transmission dominates. We find that intensive promotion of good hand washing practices may prevent outbreaks. Isolation of ill passengers and cleaning are beneficial, but appear to be less efficacious at outbreak control.

Sunspot activity and influenza pandemics: a statistical assessment of the purported association.

Since 1978, a series of papers in the literature have claimed to find a significant association between sunspot activity and the timing of influenza pandemics. This paper examines these analyses, and attempts to recreate the three most recent statistical analyses by Ertel (1994), Tapping et al. (2001), and Yeung (2006), which all have purported to find a significant relationship between sunspot numbers and pandemic influenza. As will be discussed, each analysis had errors in the data. In addition, in each analysis arbitrary selections or assumptions were also made, and the authors did not assess the robustness of their analyses to changes in those arbitrary assumptions. Varying the arbitrary assumptions to other, equally valid, assumptions negates the claims of significance. Indeed, an arbitrary selection made in one of the analyses appears to have resulted in almost maximal apparent significance; changing it only slightly yields a null result. This analysis applies statistically rigorous methodology to examine the purported sunspot/pandemic link, using more statistically powerful un-binned analysis methods, rather than relying on arbitrarily binned data. The analyses are repeated using both the Wolf and Group sunspot numbers. In all cases, no statistically significant evidence of any association was found. However, while the focus in this particular analysis was on the purported relationship of influenza pandemics to sunspot activity, the faults found in the past analyses are common pitfalls; inattention to analysis reproducibility and robustness assessment are common problems in the sciences, that are unfortunately not noted often enough in review.

Mass Measurement of 56Sc Reveals a Small A = 56 Odd-Even Mass Staggering, Implying a Cooler Accreted Neutron Star Crust.

We present the mass excesses of (52-57)Sc, obtained from recent time-of-flight nuclear mass measurements at the National Superconducting Cyclotron Laboratory at Michigan State University. The masses of 56Sc and 57Sc were determined for the first time with atomic mass excesses of -24.85(59)((-54)(+0)) MeV and -21.0(1.3) MeV, respectively, where the asymmetric uncertainty for 56Sc was included due to possible contamination from a long-lived isomer. The 56Sc mass indicates a small odd-even mass staggering in the A = 56 mass chain towards the neutron drip line, significantly deviating from trends predicted by the global FRDM mass model and favoring trends predicted by the UNEDF0 and UNEDF1 density functional calculations. Together with new shell-model calculations of the electron-capture strength function of 56Sc, our results strongly reduce uncertainties in model calculations of the heating and cooling at the 56Ti electron-capture layer in the outer crust of accreting neutron stars. We find that, in contrast to previous studies, neither strong neutrino cooling nor strong heating occurs in this layer. We conclude that Urca cooling in the outer crusts of accreting neutron stars that exhibit superbursts or high temperature steady-state burning, which are predicted to be rich in A≈56 nuclei, is considerably weaker than predicted. Urca cooling must instead be dominated by electron capture on the small amounts of adjacent odd-A nuclei contained in the superburst and high temperature steady-state burning ashes. This may explain the absence of strong crust Urca cooling inferred from the observed cooling light curve of the transiently accreting x-ray source MAXI J0556-332.

Mass measurements demonstrate a strong N=28 shell gap in argon.

We present results from recent time-of-flight nuclear mass measurements at the National Superconducting Cyclotron Laboratory at Michigan State University. We report the first mass measurements of ^{48}Ar and ^{49}Ar and find atomic mass excesses of -22.28(31) MeV and -17.8(1.1) MeV, respectively. These masses provide strong evidence for the closed shell nature of neutron number N=28 in argon, which is therefore the lowest even-Z element exhibiting the N=28 closed shell. The resulting trend in binding-energy differences, which probes the strength of the N=28 shell, compares favorably with shell-model calculations in the sd-pf shell using SDPF-U and SDPF-MU Hamiltonians.

Improving the control of systematic uncertainties in precision measurements of radionuclide half-life.

Many experiments designed to precisely determine the half-life of a radionuclide employ a long lived reference source to help determine the impact on the data of any systematic variation in the detector and associated electronics. The half-life of the radionuclide of interest is determined from the ratio of its decay rate data to the decay rate data from the reference source. This correction procedure assumes that any underlying systematic affects the data and reference measurements in exactly the same way. In this paper we show that when some systematic effects affect the two differently, the ratio procedure can leave artifacts in the corrected data that can compromise an unbiased and precise assessment of the radionuclide half-life. We describe two methods that can help overcome this problem. We also describe several statistical tests that help determine which effects may underlie systematic variations in the data. We discuss an illustrative example based on previously published (32)Si and (36)Cl data recorded by an experiment at Brookhaven National Laboratory. We correct the data for systematic variation related to climate variation and estimate the (32)Si half-life to be T1/2=171.8±1.8. The reduction in uncertainty in the (32)Si half-life, relative to the previous estimate based upon this data, is equivalent to that which would be achieved through increasing the size of the data set by almost 3.5 times.

Social contact patterns and control strategies for influenza in the elderly.

Despite dramatic increases in influenza vaccination coverage in the elderly population over the past 30 years, influenza mortality rates have remained static in this age group. Children are believed to be the primary spreaders of diseases such as influenza due to their high degree of inter-contact in school settings, and several studies have examined control of influenza in the entire population, including the elderly, via targeted vaccination of school children. However, such vaccination programs are expensive, and fraught with difficulties of public perception of what may be seen as an unnecessary vaccination against a disease that is normally mild in the children themselves. In the study presented here, we examine the control of influenza in the elderly using simple social distancing measures during an influenza epidemic. The recent work of Glasser et al. characterizes daily contact interactions within the population in terms of preferential mixing between age group peers, co-workers, and parents and children. We expand upon this to include interactions between grandparents and grandchildren, and fit the parameters of this formulation to the recently published social contact survey data of Mossong et al. Using this formulation, we then model an influenza epidemic with an age-structured deterministic disease model and examine how reduction in contacts between grandchildren and grandparents affects the spread of influenza to the elderly. We find that over 50% of all influenza infections in the elderly are caused by direct contact with an infected child, and we determine that social distancing between grandparents and grandchildren is remarkably effective, and is capable of reducing influenza attack rates in the elderly by up to 60%.

Impact of weekday social contact patterns on the modeling of influenza transmission, and determination of the influenza latent period.

Human social contact patterns show marked day-of-week variations, with a higher frequency of contacts occurring during weekdays when children are in school, and adults are in contact with co-workers, than typically occur on weekends. Using epidemic modeling, we show that using the average of social contacts during the week in the model yields virtually identical predictions of epidemic final size and the timing of the epidemic incidence peak as a model that incorporates weekday social contact patterns. This is true of models with a constant weekly average contact rate throughout the year, and also of models that assume seasonality of transmission. Our modeling studies reveal, however, that weekday social contact patterns can produce substantial weekday variations in an influenza incidence curve, and the pattern of variation is sensitive to the influenza latent period. The possible observability of weekday patterns in daily influenza incidence data opens up an interesting avenue of further inquiry that can shed light on the latent period of pandemic influenza. The duration of the latent period must be known with precision in order to design effective disease intervention strategies, such as use of antivirals. For a hypothetical influenza pandemic, we thus perform a simulation study to determine the number of cases needed to observe the weekday variation pattern in influenza epidemic incidence data. Our studies suggest that these patterns should be observable at 95% confidence in daily influenza hospitalization data from large cities over 75% of the time. Using 2009 A(H1N1) daily case data recorded by a large hospital in Santiago, Chile, we show that significant weekday incidence patterns are evident. From these weekday incidence patterns, we estimate the latent period of influenza to be [0.04, 0.60] days (95% CI). This method for determination of the influenza latent period in a community setting is novel, and unique in its approach.

Antiviral treatment for pandemic influenza: assessing potential repercussions using a seasonally forced SIR model.

When resources are limited, measures to control an incipient influenza pandemic must be carefully considered. Because several months are needed to mass-produce vaccines once a new pandemic strain has been identified, antiviral drugs are often considered the first line of defense in a pandemic situation. Here we use an SIR disease model with periodic transmission rate to assess the efficacy of control strategies via antiviral drug treatment during an outbreak of pandemic influenza. We show that in some situations, and independent of drug-resistance effects, antiviral treatment can have a detrimental impact on the final size of the pandemic. Antiviral treatment also has the potential to increase the size of the major peak of the pandemic, and cause it to occur earlier than it would have if treatment were not used. Our studies suggest that when a disease exhibits periodic patterns in transmission, decisions of public health policy will be particularly important as to how control measures such as drug treatment should be implemented, and to what end (i.e.; towards immediate control of a current epidemic peak, or towards potential delay and/or reduction of an anticipated autumn peak).

Pandemic H1N1 influenza: predicting the course of a pandemic and assessing the efficacy of the planned vaccination programme in the United States.

We use data on confirmed cases of pandemic influenza A(H1N1), disseminated by the United States Centers for Disease Control and Prevention(US CDC), to fit the parameters of a seasonally forced Susceptible, Infective, Recovered (SIR) model. We use the resulting model to predict the course of the H1N1 influenza pandemic in autumn 2009, and we assess the efficacy of the planned CDC H1N1 vaccination campaign. The model predicts that there will be a significant wave in autumn, with 63% of the population being infected, and that this wave will peak so early that the planned CDC vaccination campaign will likely not have a large effect on the total number of people ultimately infected by the pandemic H1N1 influenza virus.

Alpha 5 subunit-containing GABAA receptors affect the dynamic range of mouse hippocampal kainate-induced gamma frequency oscillations in vitro.

Though all in vitro models of gamma frequency network oscillations are critically dependent on GABAA receptor-mediated synaptic transmission little is known about the specific role played by different subtypes of GABAA receptor. Strong expression of the alpha5 subunit of the GABAA receptor is restricted to few brain regions, amongst them the hippocampal dendritic layers. Receptors containing this subunit may be expressed on the extrasynaptic membrane of principal cells and can mediate a tonic GABAA conductance. Using hippocampal slices of wild-type (WT) and alpha5-/- mice we investigated the role of alpha5 subunits in the generation of kainate-induced gamma frequency oscillations (20-80 Hz). The change in power of the oscillations evoked in CA3 by increasing network drive (kainate, 50-400 nm) was significantly greater in alpha5-/- than in WT slices. However, the change in frequency of gamma oscillations with increasing network drive seen in WT slices was absent in alpha5-/- slices. Raising the concentration of extracellular GABA by bathing slices in the GABA transaminase inhibitor vigabatrin and blocking uptake with tiagabine reduced the power of gamma oscillations more in WT slices than alpha5-/- slices (43%versus 15%). The data suggest that loss of this GABAA receptor subunit alters the dynamic profile of gamma oscillations to changes in network drive, possibly via actions of GABA at extrasynaptic receptors.

Impaired electrical signaling disrupts gamma frequency oscillations in connexin 36-deficient mice.

Neural processing occurs in parallel in distant cortical areas even for simple perceptual tasks. Associated cognitive binding is believed to occur through the interareal synchronization of rhythmic activity in the gamma (30-80 Hz) range. Such oscillations arise as an emergent property of the neuronal network and require conventional chemical neurotransmission. To test the potential role of gap junction-mediated electrical signaling in this network property, we generated mice lacking connexin 36, the major neuronal connexin. Here we show that the loss of this protein disrupts gamma frequency network oscillations in vitro but leaves high frequency (150 Hz) rhythms, which may involve gap junctions between principal cells (Schmitz et al., 2001), unaffected. Thus, specific connexins differentially deployed throughout cortical networks are likely to regulate different functional aspects of neuronal information processing in the mature brain.

GABAB receptor protein and mRNA distribution in rat spinal cord and dorsal root ganglia.

The presence of metabotropic receptors for GABA, GABAB, on primary afferent terminals in mammalian spinal cord has been previously reported. In this study we provide further evidence to support this in the rat and show that the GABAB receptor subunits GABAB1 and GABAB2 mRNA and the corresponding subunit proteins are present in the spinal cord and dorsal root ganglion. We also show that the predominant GABAB1 receptor subunit mRNA present in the afferent fibre cell body appears to be the 1a form. In frozen sections of lumbar spinal cord and dorsal root ganglia (DRG) GABAB receptors were labelled with [3H]CGP 62349 or the sections postfixed with paraformaldehyde and subjected to in situ hybridization using oligonucleotides designed to selectively hybridize with the mRNA for GABAB(1a), GABAB(1b) or GABAB2. For immunocytochemistry (ICC), sections were obtained from rats anaesthetized and perfused-fixed with paraformaldehyde. The distribution of binding sites for [3H]CGP 62349 mirrored that previously observed with [3H]GABA at GABAB sites. The density of binding sites was high in the dorsal horn but much lower in the ventral regions. By contrast, the density of mRNA (pan) was more evenly distributed across the laminae of the spinal cord. The density of mRNA detected with the pan probe was high in the DRG and distributed over the neuron cell bodies. This would accord with GABAB receptor protein being formed in the sensory neurons and transported to the primary afferent terminals. Of the GABAB1 mRNA in the DRG, approximately 90% was of the GABAB(1a) form and approximately 10% in the GABAB(1b) form. This would suggest that GABAB(1a) mRNA may be responsible for encoding presynaptic GABAB receptors on primary afferent terminals in a manner similar to that we have previously observed in the cerebellar cortex. GABAB2 mRNA was also evenly distributed across the spinal cord laminae at densities equivalent to those of GABAB1 in the dorsal horn. GABAB2 mRNA was also detected to the same degree within the DRG. Immunocytochemical analysis revealed that GABAB(1a), GABAB(1b) and GABAB2 were all present in the spinal cord. GABAB(1a) labelling appeared to be more dense than GABAB(1b) and within the superficial dorsal horn GABAB(1a) was present in the neuropil whereas GABAB(1b) was associated with cell bodies in this region. Both 1a and 1b immunoreactivity was expressed in motor neurons in lamina IX. GABAB2 immunoreactivity was expressed throughout the spinal cord and was evident within the neuropil of the superficial laminae.

Teenage pregnancy: an update.

In 1999 the DOH set a target to reduce conceptions in under 18s by 50% by the year 2010. In this the Government, supported by the Children Act (1989), highlighted the fact that it would be the responsibility of every health care professional and local authority to help achieve this goal. This paper discusses current issues in relation to teen pregnancies, dispels popular misconceptions and suggests ways in which Accident and Emergency nurses can contribute.

Human vascular smooth muscle cells express receptors for CC chemokines.

Arteriosclerotic lesions are characterized by the accumulation of T lymphocytes and monocytes and the proliferation of intimal smooth muscle cells. Expression of the chemokine monocyte chemoattractant protein-1 (MCP- 1) has been observed in arteriosclerotic plaques and has been proposed to mediate the transendothelial migration of mononuclear cells. More recently, MCP-1 has been proposed to affect the proliferation and migration of vascular smooth muscle cells (VSMCs). We have used reverse transcription-polymerase chain reaction (RT-PCR) to investigate chemokine mRNA expression in human arteriosclerotic lesions obtained from surgical biopsy of diseased vascular tissue and show, in addition to MCP-1, expression of the chemokine macrophage inflammatory protein-1alpha (MIP-1alpha) at higher levels than in "normal" aortic tissue. We have also used RT-PCR to characterize the expression of known chemokine receptors by primary human VSMCs. Messenger RNA for the MIP-1alpha/RANTES receptor, CCR-1, and the MCP-1/MCP-3 receptor, CCR-2, was expressed by unstimulated VSMCs grown under serum-free culture conditions for 24 hours. The receptors CCR-3, CCR-4, CCR-5, CXCR-1, and CXCR-2 were not expressed by VSMCs. The presence of functionally coupled receptors for MIP-1alpha on VSMCs was demonstrated by specific binding of biotinylated MIP-1alpha and increases in intracellular Ca2+ levels after exposure to this chemokine. Taken together, these results suggest that chemokines are likely to be involved in arteriosclerosis and may play a role in modulating the function of VSMCs in vivo.

Sorted.

Each year in Accident and Emergency an increasing number of young people present with acute problems related to social drugs. These problems range from mild symptoms to life-threatening conditions, many of which can be extremely difficult and time consuming for staff to manage. It has become apparent that as with sex the experimental age for taking drugs is getting younger as youths are now far more 'streetwise' than their predecessors. This is one of the main reasons for this paper being written; it is imperative that staff are equipped with the appropriate knowledge to deal with the challenge and are educated about the problems associated with current drug trends. This potentially improves the quality of care and, in turn, good communication improves relationships. Ecstasy is once again becoming increasingly popular within mainstream clubs, as recently highlighted in the media, and with it reappear its problems. This article discusses the historical aspects of Ecstasy and aims to educate staff about its use and effects and provides health promotion advice for those who are involved in the care of people who take Ecstasy.

Cervical screening: what do Auckland general practitioners do?

AIMS: To assess the frequency of cervical screening; average age of screened women and adequacy of decontamination practices of vaginal specula by Auckland general practitioners. METHODS: A random sample of 96 Auckland general practitioners completed a questionnaire at the time of consultation describing the screening history and decontamination practices for vaginal specula from five consecutive patients having a cervical smear test. RESULTS: Of the 96 doctors 68 completed the questionnaire for the five consecutive patients. The majority of women were aged below 50 years and the median time since the last smear for women with a previously normal smear was 18 months. Although the majority of doctors adhered to Health Department guidelines for decontamination, deviations occurred by: reusing plastic specula; using only disinfection as a means of decontamination and not boiling specula for 30 minutes. CONCLUSIONS: The majority of women being screened are young and there is a high level of very frequent screening in women with previously normal smears. Closer adherence to the 1991 cervical screening recommendations and Health Department guidelines for decontamination of vaginal specula is required for some Auckland general practitioners.

Prevention of Rh-haemolytic disease: results of the Liverpool "low-risk" clinical trial.

A clinical trial is reported in which Rh-negative primiparae, just delivered of an Rh-positive ABO-compatible infant and in whom fetal cell counts after delivery suggested less than 0.2 ml of circulating fetal blood, were treated with about 200 mug of anti-D gammaglobulin. Three (0.36%) out of 844 women thus treated developed anti-D in the subsequent six months; this is 10% of the incidence in untreated controls. Three (1.8%) out of 171 treated mothers had anti-D at the end of the second Rh-positive pregnancy, and this is 18% of the incidence in controls.Possible reasons for the occasional failure of the treatment are discussed and the results of this trial are compared with those of a previous trial in which 1,000 mug or more of anti-D was given to a different group of mothers. The combined results of the two trials lead to the conclusion that the passive administration of anti-D gammaglobulin after delivery affords in this population of Rh-negative women a 95% protection rate in the postdelivery period and an 89% protection rate by the end of the subsequent pregnancy.