Efficacy and Effectiveness of Mobile Health Technologies for Facilitating Physical Activity in Adolescents: Scoping Review

Background

Increasing physical activity (PA) levels in adolescents aged 12 to 18 years is associated with prevention of unhealthy weight gain and improvement in cardiovascular fitness. The widespread availability of mobile health (mHealth) and wearable devices offers self-monitoring and motivational features for increasing PA levels and improving adherence to exercise programs.

Objective

The aim of this scoping review was to identify the efficacy or effectiveness of mHealth intervention strategies for facilitating PA among adolescents aged 12 to 18 years.

Methods

We conducted a systematic search for peer-reviewed studies published between 2008 and 2018 in the following electronic databases: PubMed, Google Scholar, PsychINFO, or SportDiscus. The search terms used included mHealth or “mobile health” or apps, “physical activity” or exercise, children or adolescents or teens or “young adults” or kids, and efficacy or effectiveness. Articles published outside of the date range (July 2008 to October 2018) and non-English articles were removed before abstract review. Three reviewers assessed all abstracts against the inclusion and exclusion criteria. Any uncertainties or differences in opinion were discussed as a group. The inclusion criteria were that the studies should (1) have an mHealth component, (2) target participants aged between 12 and 18 years, (3) have results on efficacy or effectiveness, and (4) assess PA-related outcomes. Reviews, abstracts only, protocols without results, and short message service text messaging–only interventions were excluded. We also extracted potentially relevant papers from reviews. At least 2 reviewers examined all full articles for fit with the criteria and extracted data for analysis. Data extracted from selected studies included study population, study type, components of PA intervention, and PA outcome results.

Results

Overall, 126 articles were initially identified. Reviewers pulled 18 additional articles from excluded review papers. Only 18 articles were passed onto full review, and 16 were kept for analysis. The included studies differed in the sizes of the study populations (11-607 participants), locations of the study sites (7 countries), study setting, and study design. Overall, 5 mHealth intervention categories were identified: website, website+wearable, app, wearable+app, and website+wearable+app. The most common measures reported were subjective weekly PA (4/13) and objective daily moderate-to-vigorous PA (5/13) of the 19 different PA outcomes assessed. Furthermore, 5 of 13 studies with a control or comparison group showed a significant improvement in PA outcomes between the intervention group and the control or comparison group. Of those 5 studies, 3 permitted isolation of mHealth intervention components in the analysis.

Conclusions

PA outcomes for adolescents improved over time through mHealth intervention use; however, the lack of consistency in chosen PA outcome measures, paucity of significant outcomes via between-group analyses, and the various study designs that prevent separating the effects of intervention components calls into question their true effect.

Social Status and Adolescent Physical Activity: Expanding the Insurance Hypothesis to Incorporate Energy Expenditure

Low social status (SS) is a determinant of poor health status and is associated with increased disease burden. Obesity affects 20.6% of American adolescents, most of whom are from low-SS families. Contributors to the development of obesity among adolescents include sedentary behavior and low levels of physical activity. Environmental determinants-infrastructure, policy, and social relationships-influence engagement in physical activity and are affected by SS. Significant declines in physical activity have been documented during adolescence, and adolescents of low SS engage in significantly less physical activity per week than those with high SS. This article briefly reviews the literature on the relationship between SS and physical activity in adolescents and introduces a proposed biological mechanism that may explain that relationship. Characterizing the effects that SS can have on physical activity may help tailor clinical interventions and public health campaigns seeking to improve adolescent physical activity and weight management, thus increasing their effectiveness. This may be particularly beneficial for underserved populations.

Genome-wide association studies of smooth pursuit and antisaccade eye movements in psychotic disorders: findings from the B-SNIP study

Eye movement deviations, particularly deficits of initial sensorimotor processing and sustained pursuit maintenance, and antisaccade inhibition errors, are established intermediate phenotypes for psychotic disorders. We here studied eye movement measures of 849 participants from the Bipolar-Schizophrenia Network on Intermediate Phenotypes (B-SNIP) study (schizophrenia N=230, schizoaffective disorder N=155, psychotic bipolar disorder N=206 and healthy controls N=258) as quantitative phenotypes in relation to genetic data, while controlling for genetically derived ancestry measures, age and sex. A mixed-modeling genome-wide association studies approach was used including ~4.4 million genotypes (PsychChip and 1000 Genomes imputation). Across participants, sensorimotor processing at pursuit initiation was significantly associated with a single nucleotide polymorphism in IPO8 (12p11.21, P=8 × 10-11), whereas suggestive associations with sustained pursuit maintenance were identified with SNPs in SH3GL2 (9p22.2, P=3 × 10-8). In participants of predominantly African ancestry, sensorimotor processing was also significantly associated with SNPs in PCDH12 (5q31.3, P=1.6 × 10-10), and suggestive associations were observed with NRSN1 (6p22.3, P=5.4 × 10-8) and LMO7 (13q22.2, P=7.3x10-8), whereas antisaccade error rate was significantly associated with a non-coding region at chromosome 7 (P=6.5 × 10-9). Exploratory pathway analyses revealed associations with nervous system development and function for 40 top genes with sensorimotor processing and pursuit maintenance (P=4.9 × 10-2-9.8 × 10-4). Our findings suggest novel patterns of genetic variation relevant for brain systems subserving eye movement control known to be impaired in psychotic disorders. They include genes involved in nuclear trafficking and gene silencing (IPO8), fast axonal guidance and synaptic specificity (PCDH12), transduction of nerve signals (NRSN1), retinal degeneration (LMO7), synaptic glutamate release (SH3GL2), and broader nervous system development and function.

Mobile Device Accuracy for Step Counting Across Age Groups

Background

Only one in five American meets the physical activity recommendations of the Department of Health and Human Services. The proliferation of wearable devices and smartphones for physical activity tracking has led to an increasing number of interventions designed to facilitate regular physical activity, in particular to address the obesity epidemic, but also for cardiovascular disease patients, cancer survivors, and older adults. However, the inconsistent findings pertaining to the accuracy of wearable devices for step counting needs to be addressed, as well as factors known to affect gait (and thus potentially impact accuracy) such as age, body mass index (BMI), or leading arm.

Objective

We aim to assess the accuracy of recent mobile devices for counting steps, across three different age groups.

Methods

We recruited 60 participants in three age groups: 18-39 years, 40-64 years, and 65-84 years, who completed two separate 1000 step walks on a treadmill at a self-selected speed between 2 and 3 miles per hour. We tested two smartphones attached on each side of the waist, and five wrist-based devices worn on both wrists (2 devices on one wrist and 3 devices on the other), as well as the Actigraph wGT3X-BT, and swapped sides between each walk. All devices were swapped dominant-to-nondominant side and vice-versa between the two 1000 step walks. The number of steps was recorded with a tally counter. Age, sex, height, weight, and dominant hand were self-reported by each participant.

Results

Among the 60 participants, 36 were female (60%) and 54 were right-handed (90%). Median age was 53 years (min=19, max=83), median BMI was 24.1 (min=18.4, max=39.6). There was no significant difference in left- and right-hand step counts by device. Our analyses show that the Fitbit Surge significantly undercounted steps across all age groups. Samsung Gear S2 significantly undercounted steps only for participants among the 40-64 year age group. Finally, the Nexus 6P significantly undercounted steps for the group ranging from 65-84 years.

Conclusions

Our analysis shows that apart from the Fitbit Surge, most of the recent mobile devices we tested do not overcount or undercount steps in the 18-39-year-old age group, however some devices undercount steps in older age groups. This finding suggests that accuracy in step counting may be an issue with some popular wearable devices, and that age may be a factor in undercounting. These results are particularly important for clinical interventions using such devices and other activity trackers, in particular to balance energy requirements with energy expenditure in the context of a weight loss intervention program.

Radiation safety awareness among medical interns: are EU guidelines being implemented?

BACKGROUND

European recommendations suggest that medical students should be taught radiation safety before entering clinical practice.

AIM

The aim of this study was to produce a summative assessment of radiation protection training in medical school in Ireland.

MATERIALS AND METHODS

A web-based questionnaire was distributed to the 2014 intern population (n = 683) via network intern-coordinators. The survey encompassed knowledge of radiation dose in X-ray investigations, laws governing the prescribing of radiation and complications of radiation exposure to staff and patients.

RESULTS

Response rate was 14.2% (97/683) with all Irish medical schools represented. 64% of interns reported no formal training in radiation safety. 80% correctly identified MRI and 94% US as not posing a radiation risk. 54% identified CT PET as emitting the highest radiation dose to patients. Only 32% correctly identified one CT abdomen/pelvis as equivalent to the dose from 300 to 500 chest X-rays and 22% correctly identified the theoretical lifetime risk of cancer induction from CT abdomen/pelvis as 1 in 2000. While 71% thought it was very important that prescribers should be aware of patient radiation dose and 28% thought it was moderately important, 74% were not aware of any laws governing the prescribing of radiology investigations.

CONCLUSION

Currently, there is little formal radiation safety training in Irish medical schools. Knowledge of radiation dose and the laws governing prescribing is limited among qualifying interns. Implementation of a formal radiation safety curriculum in Irish Medical Schools would adhere to EU guidelines and improve prescriber knowledge, patient, and personal radiation safety.

Endovascular Therapy Research in Lower Limb Peripheral Arterial Disease Published Over a 5-Year Period: Who is Publishing and Where?

INTRODUCTION

Peripheral arterial disease (PAD) is being increasingly managed by endovascular therapies. In this study, we identified the clinical services publishing research as well as the journals of publication over a 5-year period.

METHODS

Twenty keywords and phrases related to endovascular intervention were identified, and a literature search was performed through the PubMed database from January 2009 to January 2014. Inclusion criteria were English language, study population more than five patients, and matching the keyword search. Eligible studies were collated into a database and classified by journal of publication, PubMed number, article title, publishing clinical service, type of publication, country of origin, and authors.

RESULTS

825 studies from 114 different journals were identified. 297 papers were excluded. Of the 528 included papers, 204 (39%) were published by Vascular Surgery (VS), 157 (30%) by Interventional Radiology (IR), 101 (19%) by Cardiology, 43 (8%) by Angiology, 6 (1%) by Vascular Medicine, and 17 (3%) from miscellaneous services. 283 (54%) studies originated from Europe, 157 (30%) from North America, 76 (14%) from Asia, 6 from Australia, 3 each from South America and Africa. IR published the most papers on PAD endovascular intervention in Europe with VS second while this trend was reversed in the USA. The 528 papers were published in 98 different journals with retrospective case series (72%), the majority.

CONCLUSION

IR continues to play a significant research role in endovascular intervention in PAD, particularly in Europe, and specifically in below the knee intervention, pedal intervention, and drug-eluting technologies.

Survey on examining prevalence of paternal anxiety and its risk factors in perinatal period in Hong Kong: a longitudinal study

BACKGROUND

There is emerging evidence of the significance of paternal mental health problems among the expectant fathers during the antenatal and postnatal period. The present study aims at determining the prevalence of paternal perinatal anxiety and identifying its risk factors among the fathers.

METHODS

A total of 622 expectant fathers were recruited in Hong Kong. The expectant fathers were assessed using standardized and validated psychological instruments on three time points including early pregnancy, late pregnancy and 6 week postnatal. Independent samples t-test, one way ANOVA, Pearson's correlation and multiple linear regression were used to examine the effect of hypothesized risk factors. Hierarchical multiple regression and mixed effect model were also conducted with potential confounding factors controlled for.

RESULTS

Results showed that a significant proportion of expectant fathers experienced anxiety during the perinatal period. Low self-esteem and poor social support were found to be risk factors of paternal anxiety across pregnancy to postnatal period. Work-family conflict could significantly predict paternal anxiety in the pregnancy period.

CONCLUSIONS

The present study points to the need for greater research and clinical attention to paternal anxiety, given that it is a highly prevalent problem and could be detrimental to their partner's well-being and children development. The present findings contributes to the theoretical understanding of the prevalence and risk factors of paternal perinatal anxiety and have implications for the design of effective identification, prevention, and interventions of these clinical problems.

PKCε phosphorylates α4β2 nicotinic ACh receptors and promotes recovery from desensitization

BACKGROUND AND PURPOSE

Nicotinic (ACh) receptor recovery from desensitization is modulated by PKC, but the PKC isozymes and the phosphorylation sites involved have not been identified. We investigated whether PKCε phosphorylation of α4β2 nAChRs regulates receptor recovery from desensitization.

EXPERIMENTAL APPROACH

Receptor recovery from desensitization was investigated by electrophysiological characterization of human α4β2 nAChRs. Phosphorylation of the α4 nAChR subunit was assessed by immunoblotting of mouse synaptosomes. Hypothermia induced by sazetidine-A and nicotine was measured in Prkce(-/-) and wild-type mice.

KEY RESULTS

Inhibiting PKCε impaired the magnitude of α4β2 nAChR recovery from desensitization. We identified five putative PKCε phosphorylation sites in the large intracellular loop of the α4 subunit, and mutating four sites to alanines also impaired recovery from desensitization. α4 nAChR subunit phosphorylation was reduced in synaptosomes from Prkce(-/-) mice. Sazetidine-A-induced hypothermia, which is mediated by α4β2 nAChR desensitization, was more severe and prolonged in Prkce(-/-) than in wild-type mice.

CONCLUSIONS AND IMPLICATIONS

PKCε phosphorylates the α4 nAChR subunit and regulates recovery from receptor desensitization. This study illustrates the importance of phosphorylation in regulating α4β2 receptor function, and suggests that reducing phosphorylation prolongs receptor desensitization and decreases the number of receptors available for activation.

Enhanced Recovery Achieving the Aims of Head and Neck Cancer Surveillance: A Traffic Light System

Objectives:

Post-treatment head and neck cancer surveillance (PTHNCS) shows inconsistency in the duration of surveillance and frequency between reviews; its rationale is controversial although generally accepted. We pilot a PTHNCS that uses the principles of enhanced recovery and implements the recommendations of the Head and Neck Cancer multi-disciplinary 2011 guidelines (HNCMDG).

Methods:

Retrospective review. The recommendations of the HNCMDG 2011 were used to generate a 15 visit, 5 year PTHNCS protocol. A traffic light analogy explains its rationale and reinforces the positive implications associated with progression to patients. A patient appointment/information card has been developed to outline the five year surveillance schedule and highlight red flag symptoms that suggest recurrence and require early review. The follow up of all patients who completed chemoradiation for HNC in the first half of 2011 was compared.

Results:

47 patients received treatment: 21 patients on PTHNCS protocol, 20 (95%) attended the minimum number of visits, 4 requested additional reviews (one for a synchronous primary), none lost to follow up, 1 died. 26 patients followed at the clinicians discretion, 11 (42%) attended the minimum number of appointments, 2 did not, 1 never saw the surgical team, 1 lost to follow up, 11 died.

Conclusions:

Empowering patients to participate in their follow up while educating them as to symptoms that require earlier review allows an increase in interval follow up of asymptomatic patients. Symptomatic patients initiate an earlier review. Fewer patients are lost to follow up.

A low-dimensional deformation model for cancer cells in flow

A low-dimensional parametric deformation model of a cancer cell under shear flow is developed. The model is built around an experiment in which MDA-MB-231 adherent cells are subjected to flow with increasing shear. The cell surface deformation is imaged using differential interference contrast microscopy imaging techniques until the cell releases into the flow. We post-process the time sequence of images using an active shape model from which we obtain the principal components of deformation. These principal components are then used to obtain the parameters in an empirical constitutive equation determining the cell deformations as a function of the fluid normal and shear forces imparted. The cell surface is modeled as a 2D Gaussian interface which can be deformed with three active parameters: H (height), σ(x) (x-width), and σ(y) (y-width). Fluid forces are calculated on the cell surface by discretizing the surface with regularized Stokeslets, and the flow is driven by a stochastically fluctuating pressure gradient. The Stokeslet strengths are obtained so that viscous boundary conditions are enforced on the surface of the cell and the surrounding plate. We show that the low-dimensional model is able to capture the principal deformations of the cell reasonably well and argue that active shape models can be exploited further as a useful tool to bridge the gap between experiments, models, and numerical simulations in this biological setting.

A limited role for TP53 mutation in the transformation of follicular lymphoma to diffuse large B-cell lymphoma

The role of TP53 mutation in transformation of follicular lymphoma (FL) to diffuse large B-cell lymphoma (t-FL) was examined in a panel of 91 lymph node biopsies derived from 29 patients pre- and post-transformation. The entire TP53 coding sequence was screened and immunocytochemistry performed to determine expression of p53 and its key regulator MDM2. A total of 10 mutations were detected in eight patients (28%), although none were present at FL diagnosis. Mutations were not detected solely at the time of transformation; in three patients, mutated TP53 arose in at least one antecedent FL sample (6 months, 2.5 years and 4 years prior to transformation). Loss of heterozygosity at the TP53 locus occurred in 2/20 informative patients (only in t-FL samples). p53 staining was positive in 82% (9/11) of available biopsies with a missense mutation, and negative in 71% (45/63) with wtTP53. MDM2 expression was significantly higher in t-FL samples (mean 72% positive; 95% confidence interval (95% CI) 68-76%) than FL (mean 58% positive; 95% CI 54-62%) (P<0.001) but did not correlate with TP53 status. TP53 mutation has only a limited role in the transformation of FL, exerting a heterogeneous influence upon phenotypic change. In contrast, dysregulation of MDM2 is frequent and may provide a more rational therapeutic target..

CD23 expression in mediastinal large B-cell lymphomas

AIMS

Mediastinal large B-cell lymphoma (MLBCL) is a subtype of diffuse large B-cell lymphoma (DLBCL) in the WHO classification with peculiar features, such as female prevalence, young patient age and bulky presentation. It shows a B-cell phenotype with variable expression of surface immunoglobulin, negative CD21 and CD10 and positive CD30 in a large number of cases. An origin from activated thymic B cells has been suggested in several studies. A subpopulation of large, dendritic cells (asteroid cells) strongly expressing CD23 has been identified amongst thymic B cells and these could represent the normal cellular counterpart for this type of primary mediastinal large cell lymphoma.

METHODS AND RESULTS

To explore this possibility, we immunostained 24 cases of primary mediastinal lymphomas and 100 cases of non-mediastinal, nodal and extranodal, DLBCLs for CD23 in routinely processed paraffin-embedded tissues.

CONCLUSIONS

Our results show that a vast majority (70%) of mediastinal lymphomas strongly express CD23 whilst the same antigen is expressed in only 15% of non-mediastinal nodal DLBCLs and 9% of non-mediastinal extranodal DLBCLs. These results support the hypothesis that most cases of MLBCL arise from activated dendritic thymic B cells. We also suggest that CD23 should be included in the panel of antibodies currently used to characterize this subtype of DLBCL.

Diversity of bacterial populations on the tongue dorsa of patients with halitosis and healthy patients

The primary purpose of the present study was to compare the microbial profiles of the tongue dorsa of healthy subjects and subjects with halitosis by using culture-independent molecular methods. Our overall goal was to determine the bacterial diversity on the surface of the tongue dorsum as part of our ongoing efforts to identify all cultivable and not-yet-cultivated species of the oral cavity. Tongue dorsum scrapings were analyzed from healthy subjects with no complaints of halitosis and subjects with halitosis, defined as an organoleptic score of 2 or more and volatile sulfur compound levels greater than 200 ppb. 16S rRNA genes from DNA isolated from tongue dorsum scrapings were amplified by PCR with universally conserved bacterial primers and cloned into Escherichia coli. Typically, 50 to 100 clones were analyzed from each subject. Fifty-one strains isolated from the tongue dorsa of healthy subjects were also analyzed. Partial sequences of approximately 500 bases of cloned inserts from the 16S rRNA genes of isolates were compared with sequences of known species or phylotypes to determine species identity or closest relatives. Nearly complete sequences of about 1,500 bases were obtained for potentially novel species or phylotypes. In an analysis of approximately 750 clones, 92 different bacterial species were identified. About half of the clones were identified as phylotypes, of which 29 were novel to the tongue microbiota. Fifty-one of the 92 species or phylotypes were detected in more than one subject. Those species most associated with healthy subjects were Streptococcus salivarius, Rothia mucilaginosa, and an uncharacterized species of Eubacterium (strain FTB41). Streptococcus salivarius was the predominant species in healthy subjects, as it represented 12 to 40% of the total clones analyzed from each healthy subject. Overall, the predominant microbiota on the tongue dorsa of healthy subjects was different from that on the tongue dorsa of subjects with halitosis. Those species most associated with halitosis were Atopobium parvulum, a phylotype (clone BS095) of Dialister, Eubacterium sulci, a phylotype (clone DR034) of the uncultivated phylum TM7, Solobacterium moorei, and a phylotype (clone BW009) of STREPTOCOCCUS: On the basis of our ongoing efforts to obtain full 16S rRNA sequences for all cultivable and not-yet-cultivated species that colonize the oral cavity, there are now over 600 species.

Risk factors for hepatotoxicity associated with rifampin and pyrazinamide for the treatment of latent tuberculosis infection: experience from three public health tuberculosis clinics

SETTING

Three municipal tuberculosis (TB) clinics.

OBJECTIVES

Reports of liver injury in patients treated with a 2-month regimen of daily rifampin and pyrazinamide (2RZ) for latent TB infection have raised concern about its safety. We aimed to evaluate the safety and tolerability of 2RZ and identify risk factors for hepatotoxicity.

METHODS

We reviewed charts of adults started on 2RZ between 1999 and 2001. Cases with grade 3 hepatotoxicity (AST or ALT >5.0-20.0 x upper limit of normal) and grade 4 hepatotoxicity (AST or ALT >20.0 x upper limit of normal) were identified.

RESULTS

Of 148 patients prescribed 2RZ, 85 (57.4%) completed therapy. Grade 3 or 4 hepatotoxicity occurred in 14 patients (eight grade 4 cases). In multivariate analysis, hepatotoxicity was associated with female sex (odds ratio [OR] 4.1; 95% confidence interval [CI] 1.2-14.3) and with presumed recent infection (recent tuberculin skin test conversion or contact with a TB case) (OR 14.3; 95%CI 1.8-115), but not with alcohol use, illicit drug use, age, race, or pyrazinamide dose.

CONCLUSIONS

Hepatotoxicity occurred in a high proportion of patients prescribed 2RZ, and was more common among females and those with recent infection. Caution is warranted in using 2RZ in populations where its safety has not been established.

Diffractive dijet production at sqrt[s] = 630 and 1800 GeV at the Fermilab Tevatron

We report a measurement of the diffractive structure function F(D)(jj) of the antiproton obtained from a study of dijet events produced in association with a leading antiproton in pp collisions at sqrt[s] = 630 GeV at the Fermilab Tevatron. The ratio of F(D)(jj) at sqrt[s] = 630 GeV to F(D)(jj) obtained from a similar measurement at sqrt[s] = 1800 GeV is compared with expectations from QCD factorization and other theoretical predictions. We also report a measurement of the xi ( x-Pomeron) and beta ( x of parton in Pomeron) dependence of F(D)(jj) at sqrt[s] = 1800 GeV. In the region 0.035<xi<0.095, /t/<1 GeV2, and beta<0.5, F(D)(jj)(beta,xi) is found to be of the form beta(-1.0+/-0.1)xi(-0.9+/-0.1), which obeys beta-xi factorization.

Search for new heavy particles in the WZ0 final state in pp collisions at square root[s] = 1.8 TeV

We present the first general search for new heavy particles, X, which decay via X --> WZ0 --> e(nu)+jj as a function of M(X) and Gamma(X) in pp collisions at square root[s] = 1.8 TeV. No evidence is found for production of X in 110 pb(-1) of data collected by the Collider Detector at Fermilab. General cross section limits are set at the 95% C.L. as a function of mass and width of the new particle. The results are further interpreted as mass limits on the production of new heavy charged vector bosons which decay via W' --> WZ0 in an extended gauge model as a function of the width, Gamma(W'), and mixing factor between the W' and the standard model W bosons.

Study of B0 --> J/psiK(*)0pi(+)pi(-) decays with the collider detector at Fermilab

We report a study of the decays B0 --> J/psiK(*)0pi(+)pi(-), which involve the creation of a uu or dd quark pair in addition to a b -->c(cs) decay. The data sample consists of 110 pb(-1) of pp collisions at square root[s] = 1.8 TeV collected by the CDF detector at the Fermilab Tevatron collider during 1992-1995. We measure the branching fractions to be B(B0 --> J/psiK(*0)pi(+)pi(-)) = (6.6 +/- 1.9 +/- 1.1)x10(-4) and B(B0 --> J/psiK0pi(+)pi(-)) = (10.3 +/- 3.3 +/- 1.5)x10(-4). Evidence is seen for contributions from psi(2S)K(*)0, J/psiK0rho(0), J/psiK(*+)pi(-), and J/psiK1(1270).

Search for gluinos and scalar quarks in pp collisions at square root[s] = 1.8 TeV using the missing energy plus multijets signature

We have performed a search for gluinos (g) and scalar quarks (q) in a data sample of 84 pb(-1) of pp collisions at square root[s] = 1.8 TeV, recorded by the Collider Detector at Fermilab. We investigate the final state of large missing transverse energy and three or more jets, a characteristic signature in R-parity-conserving supersymmetric models. The analysis has been performed "blind," in that the inspection of the signal region is made only after the predictions from standard model backgrounds have been calculated. Comparing the data with predictions of constrained supersymmetric models, we exclude gluino masses below 195 GeV/c2 (95% C.L.), independent of the squark mass. For the case m(q) approximately m(g), gluino masses below 300 GeV/c2 are excluded.

Measurement of the strong coupling constant from inclusive jet production at the Tevatron pp collider

We report a measurement of the strong coupling constant, alpha(s)(MZ), extracted from inclusive jet production in pp collisions at square root[s] = 1800 GeV. The QCD prediction for the evolution of alpha(s) with jet transverse energy ET is tested over the range 40<ET<450 GeV using ET for the renormalization scale. The data show good agreement with QCD in the region below 250 GeV. The value of alpha(s) at the mass of the Z0 boson averaged over the range 40<ET<250 GeV is found to be alpha(s)(MZ) = 0.1178+/-0.0001(stat)+0.0081(-0.0095)(expt. syst). The associated theoretical uncertainties are mainly due to the choice of renormalization scale ((+6%)(-4%)) and input parton distribution functions (5%).

Dicoumarol toxicity in cattle associated with ingestion of silage containing sweet vernal grass (Anthoxanthum odoratum)

A diagnosis of dicoumarol toxicity in a herd of Friesian cattle was made following investigation of the deaths of three mature cows and eleven yearling heifers. Affected stock had been fed wrapped, bailed silage containing approximately 90% sweet vernal grass (Anthoxanthum odoratum). Sweet vernal grass contains coumarin, which can be converted to dicoumarol, a vitamin K antagonist, through the action of moulds. Most deaths were preceded by lethargy, severe anaemia and subcutaneous and internal haemorrhage. Dicoumarol toxicosis was suspected based on clinical signs, necropsy findings and prolonged prothrombin and activated partial thromboplastin times. Dicoumarol analysis of blood from affected animals and silage confirmed the diagnosis. Activated partial thromboplastin time Haemoglobin Packed cell volume Prothrombin time Red cell count

Search for gluinos and squarks using like-sign dileptons in pp macro collisions at square root of s = 1.8 TeV

We present results of the first search for like-sign dilepton ( e(+/-)e(+/-), e(+/-)mu(+/-), mu(+/-)mu(+/-)) events associated with multijets and large missing energy using 106 pb(-1) of data in pp macro collisions at square root of s = 1.8 TeV collected during 1992-1995 by the CDF experiment. Finding no events that pass our selection, we examine pair production of gluinos (tilde g) and squarks (tilde q) in a constrained framework of the minimal supersymmetric standard model. At tan beta = 2 and mu = -800 GeV/c(2), we set 95% confidence level limits of M(tilde g)>221 GeV/c(2) for M(tilde g) approximately M(tilde q), and M(tilde q)>168 GeV/c(2) for M(tilde q)>>M(tilde g), both with small variation as a function of mu.