TABLE OF CONTENTS: A1 Point-of-care ultrasound examination of cervical spine in emergency departmentYahya Acar, Onur Tezel, Necati SalmanA2 A new technique in verifying the placement of a nasogastric tube: obtaining the longitudinal view of nasogastric tube in addition to transverse view with ultrasoundYahya Acar, Necati Salman, Onur Tezel, Erdem CevikA3 Pseudoaneurysm of the femoral artery after cannulation of a central venous line. Should we always use ultrasound in these procedures?Margarita Algaba-Montes, Alberto Oviedo-García, Mayra Patricio-BordomásA4 Ultrasound-guided supraclavicular subclavian vein catheterization. A novel approach in emergency departmentMargarita Algaba-Montes, Alberto Oviedo-García, Mayra Patricio-BordomásA5 Clinical ultrasound in a septic and jaundice patient in the emergency departmentMargarita Algaba-Montes, Alberto Oviedo-García, Mayra Patricio-BordomásA6 Characterization of the eyes in preoperative cataract Saudi patients by using medical diagnostic ultrasoundMustafa Z. Mahmoud, Abdelmoneim SuliemanA7 High-frequency ultrasound in determining the causes of acute shoulder joint painMustafa Z. MahmoudA8 Teaching WINFOCUS Ultrasound Life Support Basic Level 1 for Providers in resource-limited countriesAbbas Ali, Alrayah Mustafa, Ihab Abdelrahman, Mustafa Bahar, Osama Ali, H. Lester Kirchner, Gregor ProsenA9 Changes of arterial stiffness and endothelial function during uncomplicated pregnancyAjda Anzic, Paul LeesonA10 Cardiovascular haemodynamic properties before, during and after pregnancyAjda Anzic, Paul LeesonA11 An old man with generalized weaknessMaryam Bahreini, Fatemeh RasooliA12 Ultrasonography for non-specific presentations of abdominal painMaryam Bahreini, Houman HosseinnejadA13 Introduction of a new imaging guideline for suspected renal colic in the emergency department: effect on CT Urogram utilisationGabriel Blecher, Robert Meek, Diana Egerton-WarburtonA14 Transabdominal ultrasound screening for pancreatic cancer in Croatian military veterans: a retrospective analysis from the first Croatian veteran's hospitalEdina Ćatić Ćuti, Stanko Belina, Tihomir Vančina, Idriz KovačevićA15 The challenge of AAA: unusual case of obstructive jaundiceEdina Ćatić Ćuti, Nadan RustemovićA16 Educational effectiveness of easy-made new simulator model for ultrasound-guided procedures in pediatric patients: vascular access and foreign body managementIkwan Chang, Jin Hee Lee, Young Ho Kwak, Do Kyun KimA17 Detection of uterine rupture by point-of-care ultrasound at emergency department: a case reportChi-Yung Cheng, Hsiu-Yung Pan, Chia-Te KungA18 Abdominal probe in the hands of interns as a relevant diagnostic tool in revealing the cause of heart failureEla Ćurčić, Ena Pritišanac, Ivo Planinc, Marijana Grgić Medić, Radovan RadonićA19 Needs assessment of the potential utility of point-of-care ultrasound within the Zanzibar health systemAbiola Fasina, Anthony J. Dean, Nova L. Panebianco, Patricia S. HenwoodA20 Ultrasonographic diagnosis of tracheal compressionOliviero Fochi, Moreno Favarato, Ezio BonanomiA21 The role of ultrasound in the detection of lung infiltrates in critically ill patients: a pilot studyMarijana Grgić Medić, Ivan Tomić, Radovan RadonićA22 The SAFER Lasso; a novel approach using point-of-care ultrasound to evaluate patients with abdominal complaints in the emergency departmentYoungrock Ha, Hongchuen TohA23 Awareness and use of clinician-performed ultrasound among clinical clerkship facultyElizabeth Harmon, Wilma Chan, Cameron Baston, Gail Morrison, Frances Shofer, Nova Panebianco, Anthony J. DeanA24 Clinical outcomes in the use of lung ultrasound for the diagnosis of pediatric pneumoniasAngela Hua, Sharon Kim, James TsungA25 Effectiveness of ultrasound in hypotensive patientsIsa Gunaydin, Zeynep Kekec, Mehmet Oguzhan AyA26 Moderate-to-severe left ventricular ejection fraction related to short-term mortality of patients with post-cardiac arrest syndrome after out-of-hospital cardiac arrestJinjoo Kim, Jinhyun Kim, Gyoosung Choi, Dowon ShimA27 Usefulness of abdominal ultrasound for acute pyelonephritis diagnosis after kidney transplantationJi-Han LeeA28 Lung ultrasound for assessing fluid tolerance in severe preeclampsiaJana Ambrozic, Katja Prokselj, Miha LucovnikA29 Optic nerve sheath ultrasound in severe preeclampsiaGabrijela Brzan Simenc, Jana Ambrozic, Miha LucovnikA30 Focused echocardiography monitoring in the postoperative period for non-cardiac patientsAsta Mačiulienė, Almantas Maleckas, Algimantas Kriščiukaitis, Vytautas Mačiulis, Andrius MacasA31 POCUS-guided paediatric upper limb fracture reduction: algorithm, tricks, and tipsSharad MohiteA32 Point-of-care lung ultrasound: a good diagnostic tool for pneumonia in a septic patientZoltan Narancsik, Hugon MožinaA33 A case of undergraduate POCUS (r)evolutionSara Nikolić, Jan Hansel, Rok Petrovčič, Una Mršić, Gregor ProsenA34 The Graz Summer School for ultrasound: from first contact to bedside application: three-and-a-half-day undergraduate ultrasound training: résumé after two years of continuous developmentSimon Orlob, Markus Lerchbaumer, Niklas Schönegger, Reinhard KaufmannA35 Usefulness of point-of-care ultrasound in the emergency room in a patient with acute abdominal painAlberto Oviedo-García, Margarita Algaba-Montes, Mayra Patricio-BordomásA36 Use of bedside ultrasound in a critically ill patient. A case reportAlberto Oviedo-García, Margarita Algaba-Montes, Mayra Patricio-BordomásA37 Diagnostic yield of clinical echocardiography for the emergency physicianAlberto Oviedo-García, Margarita Algaba-Montes, Mayra Patricio-BordomásA38 Focused cardiac ultrasound in early diagnosis of type A aortic dissection with atypical presentationChun-I Pan, Hsiu-Yung Pan, Chien-Hung WuA39 Detection of imperforated hymen by point-of-care ultrasoundHsiu-yung Pan, Chia-Te KungA40 Developing a point-of-care ultrasound curriculum for pediatric nurse practitioners practicing in the pediatric emergency departmentSarah Pasquale, Stephanie J. Doniger, Sharon Yellin, Gerardo ChiricoloA41 Use of transthoracic echocardiography in emergency setting: patient with mitral valve abscessMaja Potisek, Borut Drnovšek, Boštjan LeskovarA42 A young man with syncopeFatemeh Rasooli, Maryam BahreiniA43 Work-related repetitive use injuries in ultrasound fellowsKristine Robinson, Clara Kraft, Benjamin Moser, Stephen Davis, Shelley Layman, Yusef Sayeed, Joseph MinardiA44 Lung ultrasonography in the evaluation of pneumonia in childrenIrmina Sefic Pasic, Amra Dzananovic, Anes Pasic, Sandra Vegar ZubovicA45 Central venous catheter placement with the ultrasound aid: two years' experience of the Interventional unit, Division of Intensive Care Medicine, KBC ZagrebAna Godan Hauptman, Marijana Grgic Medic, Ivan Tomic, Ana Vujaklija Brajkovic, Jaksa Babel, Marina Peklic, Radovan RadonicA46 Duplicitas casui: two patients admitted due to acute liver failureVedran Radonic, Ivan Tomic, Luka Bielen, Marijana Grgic MedicA47 A pilot survey on an understanding of Bedside Point-of-Care Ultrasound (POCUS) among medical doctors in internal medicine: exposure, perceptions, interest, and barriers to trainingPeh Wee MingA48 Unusual case of defecation syncopeNur hafiza Yezid, Fatahul Laham MohammedA49 A case report of massive pulmonary embolism; a multidisciplinary approachZainal Abidin Huda, Wan Nasarudin Wan Ismail, W.Yus Haniff W.Isa, Hashairi Fauzi, Praveena Seeva, Mohd Zulfakar Mazlan.
Bone is one of the most common sites of cancer metastasis, as its fertile microenvironment attracts tumor cells. The unique mechanical properties of bone extracellular matrix (ECM), mainly composed of hydroxyapatite (HA) affect a number of cellular responses in the tumor microenvironment (TME) such as proliferation, migration, viability, and morphology, as well as angiogenic activity, which is related to bone metastasis. In this study, we engineered a bone-mimetic microenvironment to investigate the interactions between the TME and HA using a microfluidic platform designed for culturing tumor cells in 3D bone-mimetic composite of HA and fibrin. We developed a bone metastasis TME model from colorectal cancer (SW620) and gastric cancer (MKN74) cells, which has very poor prognosis but rarely been investigated. The microfluidic platform enabled straightforward formation of 3D TME composed the hydrogel and multiple cell types. This facilitated monitoring of the effect of HA concentration and culture time on the TME. In 3D bone mimicking culture, we found that HA rich microenvironment affects cell viability, proliferation and cancer cell cytoplasmic volume in a manner dependent on the different metastatic cancer cell types and culture duration indicating the spatial heterogeneity (different origin of metastatic cancer) and temporal heterogeneity (growth time of cancer) of TME. We also found that both SW620 and MKN72 cells exhibited significantly reduced migration at higher HA concentration in our platform indicating inhibitory effect of HA in both cancer cells migration. Next, we quantitatively analyzed angiogenic sprouts induced by paracrine factors that secreted by TME and showed paracrine signals from tumor and stromal cell with a high HA concentration resulted in the formation of fewer sprouts. Finally we reconstituted vascularized TME allowing direct interaction between angiogenic sprouts and tumor-stroma microspheroids in a bone-mimicking microenvironment composing a tunable HA/fibrin composite. Our multifarious approach could be applied to drug screening and mechanistic studies of the metastasis, growth, and progression of bone tumors.
We describe a method to obtain point and dispersion estimates for the energies of jets arising from b quarks produced in proton-proton collisions at an energy of s = 13 TeV at the CERN LHC. The algorithm is trained on a large sample of simulated b jets and validated on data recorded by the CMS detector in 2017 corresponding to an integrated luminosity of 41 fb - 1 . A multivariate regression algorithm based on a deep feed-forward neural network employs jet composition and shape information, and the properties of reconstructed secondary vertices associated with the jet. The results of the algorithm are used to improve the sensitivity of analyses that make use of b jets in the final state, such as the observation of Higgs boson decay to b b ¯ .
A search in an all-jet final state for new massive resonances decaying to W W , W Z , or Z Z boson pairs using a novel analysis method is presented. The analysis is performed on data corresponding to an integrated luminosity of 77.3 fb - 1 recorded with the CMS experiment at the LHC at a centre-of-mass energy of 13 Te . The search is focussed on potential narrow-width resonances with masses above 1.2 Te , where the decay products of each W or Z boson are expected to be collimated into a single, large-radius jet. The signal is extracted using a three-dimensional maximum likelihood fit of the two jet masses and the dijet invariant mass, yielding an improvement in sensitivity of up to 30% relative to previous search methods. No excess is observed above the estimated standard model background. In a heavy vector triplet model, spin-1 Z ' and W ' resonances with masses below 3.5 and 3.8 Te , respectively, are excluded at 95% confidence level. In a bulk graviton model, upper limits on cross sections are set between 27 and 0.2 fb for resonance masses between 1.2 and 5.2 Te , respectively. The limits presented in this paper are the best to date in the dijet final state.
The atmosphere security and regulation of climate change are being continuously highlighted as a pressing issue. The crisis of climate change owing to the anthropogenic carbon dioxide emission has led many governments at federal and provincial levels to promulgate policies to address this concern. Among them is regulating the carbon dioxide emission from major industrial sources such as power plants, petrochemical industries, cement plants, and other industries that depend on the combustion of fossil fuels for energy to operate. In view of this, various CO2 capture and sequestration technologies have been investigated and presented. From this review, adsorption of CO2 on porous solid materials has been gaining increasing attention due to its cost-effectiveness, ease of application, and comparably low energy demand. Despite the myriad of advanced materials such as zeolites, carbons-based, metal-organic frameworks, mesoporous silicas, and polymers being researched, research on activated carbons (ACs) continue to be in the mainstream. Therefore, this review is endeavored to elucidate the adsorption properties of CO2 on activated carbons derived from different sources. Selective adsorption based on pore size/shape and surface chemistry is investigated. Accordingly, the effect of surface modifications of the ACs with NH3, amines, and metal oxides on adsorption performance toward CO2 is evaluated. The adsorption performance of the activated carbons under humid conditions is also reviewed. Finally, activated carbon-based composite has been surveyed and recommended as a feasible strategy to improve AC adsorption properties toward CO2. The activated carbon surface in the graphical abstract is nitrogen rich modified using ammonia through thermal treatment. The values of CO2 emissions by sources are taken from (Yoro and Daramola 2020).
A search for decays to invisible particles of Higgs bosons produced in association with a top-antitop quark pair or a vector boson, which both decay to a fully hadronic final state, has been performed using proton-proton collision data collected at s=13TeV by the CMS experiment at the LHC, corresponding to an integrated luminosity of 138fb-1. The 95% confidence level upper limit set on the branching fraction of the 125GeV Higgs boson to invisible particles, B(H→inv), is 0.54 (0.39 expected), assuming standard model production cross sections. The results of this analysis are combined with previous B(H→inv) searches carried out at s=7, 8, and 13TeV in complementary production modes. The combined upper limit at 95% confidence level on B(H→inv) is 0.15 (0.08 expected).
A search for new phenomena is performed in final states containing one or more jets and an imbalance in transverse momentum in pp collisions at a centre-of-mass energy of 13[Formula: see text]. The analysed data sample, recorded with the CMS detector at the CERN LHC, corresponds to an integrated luminosity of 2.3[Formula: see text]. Several kinematic variables are employed to suppress the dominant background, multijet production, as well as to discriminate between other standard model and new physics processes. The search provides sensitivity to a broad range of new-physics models that yield a stable weakly interacting massive particle. The number of observed candidate events is found to agree with the expected contributions from standard model processes, and the result is interpreted in the mass parameter space of fourteen simplified supersymmetric models that assume the pair production of gluinos or squarks and a range of decay modes. For models that assume gluino pair production, masses up to 1575 and 975[Formula: see text] are excluded for gluinos and neutralinos, respectively. For models involving the pair production of top squarks and compressed mass spectra, top squark masses up to 400[Formula: see text] are excluded.
INTRODUCTION: Anaplastic lymphoma kinase-positive (ALK+) anaplastic large cell lymphoma (ALCL) with a non-common pattern can be diagnostic challenging. Pathologists can be unavoidably and unintentionally blind to non-descript tumor cells in a lymphohistiocytic- (LH) or small-cell (SC)-pattern. We report a case of primary systemic ALK+ ALCL with a SC pattern that presented as secondary gastric lesions with a mixed LH and SC pattern that was masqueraded as inflammatory lesions.
CASE REPORT: A 34-year-old woman with intractable epigastric pain was referred to have repeated endoscopy with biopsy. She was found to multiple gastric erosions and nodules that were diagnosed as inflammatory lesions both endoscopically and histologically. Meanwhile, she developed an acute onset of severe back pain associated with a pathologic compression fracture in the T3 thoracic vertebral body. Imaging studies disclosed a disseminated systemic disease involving abdominopelvic lymph nodes and cervical and thoracic vertebral bodies. The needle biopsy of the pelvic lymph node disclosed diffuse proliferation of monomorphic small round cells that were diffusely positive for CD30 and ALK. A diagnosis of ALK+ ALCL with a monomorphic SC pattern was rendered.
DISCUSSION: A retrospective review of the gastric biopsies with the aid of immunohistochemistry enabled us to recognise the presence of lymphomatous infiltrates with a mixed LH and SC pattern in every piece of gastric biopsies that were repeatedly misdiagnosed as inflammatory lesions. This case illustrates a significant diagnostic pitfall of the LH- and SC-patterns in ALK+ ALCL, in which the tumour cells featuring lymphoid, plasmacytoid or histiocytoid appearance can be masqueraded as inflammatory cells.
Biohydrogen as one of the most appealing energy vector for the future represents attractive avenue in alternative energy research. Recently, variety of biohydrogen production pathways has been suggested to improve the key features of the process. Nevertheless, researches are still needed to overcome remaining barriers to practical applications such as low yields and production rates. Considering practicality aspects, this review emphasized on anaerobic membrane bioreactors (AnMBRs) for biological hydrogen production. Recent advances and emerging issues associated with biohydrogen generation in AnMBR technology are critically discussed. Several techniques are highlighted that are aimed at overcoming these barriers. Moreover, environmental and economical potentials along with future research perspectives are addressed to drive biohydrogen technology towards practicality and economical-feasibility.
To evaluate the contribution of non-synonymous-coding variants of known familial and genome-wide association studies (GWAS)-linked genes for Parkinson's disease (PD) to PD risk in the East Asian population, we sequenced all the coding exons of 39 PD-related disease genes and evaluated the accumulation of rare non-synonymous-coding variants in 375 early-onset PD cases and 399 controls. We also genotyped 782 non-synonymous-coding variants of these genes in 710 late-onset PD cases and 9046 population controls. Significant enrichment of LRRK2 variants was observed in both early- and late-onset PD (odds ratio = 1.58; 95% confidence interval = 1.29-1.93; P = 8.05 × 10(-6)). Moderate enrichment was also observed in FGF20, MCCC1, GBA and ITGA8. Half of the rare variants anticipated to cause loss of function of these genes were present in healthy controls. Overall, non-synonymous-coding variants of known familial and GWAS-linked genes appear to make a limited contribution to PD risk, suggesting that clinical sequencing of these genes will provide limited information for risk prediction and molecular diagnosis.
Foam flooding by Foam Assisted Water-Alternating-Gas (FAWAG) is an important enhanced oil recovery method that has proven successful in experimental and pilot studies. The present study is carried out to monitor the movement of the foam front once injected into the porous medium. This study aims to investigate applications of resistivity waves to monitor foam propagation in a sandstone formation. In the present lab-scale experiments and simulations, resistivity measurements were carried out to monitor the progression of foam in a sand pack, and the relationships between foam injection time and resistivity, as well as brine saturation, were studied. The brine saturation from foam simulation using CMG STAR is exported to COMSOL and calculated true formation resistivity. A diagram was produced summarizing the progression of foam through the sand pack in the function of time, which enabled us to establish how foam progressed through a porous medium. A surfactant and brine mixture was injected into the sand pack, followed by nitrogen gas to generate the foam in situ. As foam progressed through the sand pack, resistance measurements were taken in three zones of the sand pack. The resistance was then converted into resistivity and finally into brine saturation. As foam travels through the sand pack, it is predicted to displace the brine initially in place. This gradually increases each zone's resistivity (decreases the brine saturation) by displacing the brine. Also, an increase in the surfactant concentration results in higher resistivity. Finally, a comparison of three different surfactant concentrations was evaluated in terms of resistivity results, water saturation, and foam propagation monitoring to obtain the optimum surfactant concentration involved in foam flooding.
Liver transplantation is a highly complex and challenging field of clinical practice. Although it was originally developed in western countries, it has been further advanced in Asian countries through the use of living donor liver transplantation. This method of transplantation is the only available option in many countries in the Asia-Pacific region due to the lack of deceased organ donation. As a result of this clinical situation, there is a growing need for guidelines that are specific to the Asia-Pacific region. These guidelines provide comprehensive recommendations for evidence-based management throughout the entire process of liver transplantation, covering both deceased and living donor liver transplantation. In addition, the development of these guidelines has been a collaborative effort between medical professionals from various countries in the region. This has allowed for the inclusion of diverse perspectives and experiences, leading to a more comprehensive and effective set of guidelines.
Worldwide, some 240 million people have chronic hepatitis B virus (HBV), with the highest rates of infection in Africa and Asia. Our understanding of the natural history of HBV infection and the potential for therapy of the resultant disease is continuously improving. New data have become available since the previous APASL guidelines for management of HBV infection were published in 2012. The objective of this manuscript is to update the recommendations for the optimal management of chronic HBV infection. The 2015 guidelines were developed by a panel of Asian experts chosen by the APASL. The clinical practice guidelines are based on evidence from existing publications or, if evidence was unavailable, on the experts' personal experience and opinion after deliberations. Manuscripts and abstracts of important meetings published through January 2015 have been evaluated. This guideline covers the full spectrum of care of patients infected with hepatitis B, including new terminology, natural history, screening, vaccination, counseling, diagnosis, assessment of the stage of liver disease, the indications, timing, choice and duration of single or combination of antiviral drugs, screening for HCC, management in special situations like childhood, pregnancy, coinfections, renal impairment and pre- and post-liver transplant, and policy guidelines. However, areas of uncertainty still exist, and clinicians, patients, and public health authorities must therefore continue to make choices on the basis of the evolving evidence. The final clinical practice guidelines and recommendations are presented here, along with the relevant background information.
Background/Aims: There is a need for a simple and practical tool adapted for the diagnosis of chronic constipation (CC) in the Asian population. This study compared the Asian Neurogastroenterology and Motility Association (ANMA) CC tool and Rome III criteria for the diagnosis of CC in Asian subjects.
Methods: This multicenter, cross-sectional study included subjects presenting at outpatient gastrointestinal clinics across Asia. Subjects with CC alert symptoms completed a combination Diagnosis Questionnaire to obtain a diagnosis based on 4 different diagnostic methods: self-defined, investigator's judgment, ANMA CC tool, and Rome III criteria. The primary endpoint was the level of agreement/disagreement between the ANMA CC diagnostic tool and Rome III criteria for the diagnosis of CC.
Results: The primary analysis comprised of 449 subjects, 414 of whom had a positive diagnosis according to the ANMA CC tool. Rome III positive/ANMA positive and Rome III negative/ANMA negative diagnoses were reported in 76.8% and 7.8% of subjects, respectively, resulting in an overall percentage agreement of 84.6% between the 2 diagnostic methods. The overall percentage disagreement between these 2 diagnostic methods was 15.4%. A higher level of agreement was seen between the ANMA CC tool and self-defined (374 subjects [90.3%]) or investigator's judgment criteria (388 subjects [93.7%]) compared with the Rome III criteria.
Conclusion: This study demonstrates that the ANMA CC tool can be a useful for Asian patients with CC.
Study site in Malaysia: Gastroenterology clinic, University Malaya Medical Centre (UMMC), Kuala Lumpur, Malaysia
Genome-wide association studies (GWAS) and fine-mapping efforts to date have identified more than 100 prostate cancer (PrCa)-susceptibility loci. We meta-analyzed genotype data from a custom high-density array of 46,939 PrCa cases and 27,910 controls of European ancestry with previously genotyped data of 32,255 PrCa cases and 33,202 controls of European ancestry. Our analysis identified 62 novel loci associated (P C, p.Pro1054Arg) in ATM and rs2066827 (OR = 1.06; P = 2.3 × 10-9; T>G, p.Val109Gly) in CDKN1B. The combination of all loci captured 28.4% of the PrCa familial relative risk, and a polygenic risk score conferred an elevated PrCa risk for men in the ninetieth to ninety-ninth percentiles (relative risk = 2.69; 95% confidence interval (CI): 2.55-2.82) and first percentile (relative risk = 5.71; 95% CI: 5.04-6.48) risk stratum compared with the population average. These findings improve risk prediction, enhance fine-mapping, and provide insight into the underlying biology of PrCa1.
In the version of this article initially published, the name of author Manuela Gago-Dominguez was misspelled as Manuela Gago Dominguez. The error has been corrected in the HTML and PDF version of the article.
The original version of this Article contained an error in the spelling of the author Manuela Gago-Dominguez, which was incorrectly given as Manuela G. Dominguez. This has now been corrected in both the PDF and HTML versions of the Article.
The structure of nucleons is multidimensional and depends on the transverse momenta, spatial geometry, and polarization of the constituent partons. Such a structure can be studied using high-energy photons produced in ultraperipheral heavy-ion collisions. The first measurement of the azimuthal angular correlations of exclusively produced events with two jets in photon-lead interactions at large momentum transfer is presented, a process that is considered to be sensitive to the underlying nuclear gluon polarization. This study uses a data sample of ultraperipheral lead-lead collisions at sqrt[s_{NN}]=5.02 TeV, corresponding to an integrated luminosity of 0.38 nb^{-1}, collected with the CMS experiment at the LHC. The measured second harmonic of the correlation between the sum and difference of the two jet transverse momentum vectors is found to be positive, and rising, as the dijet transverse momentum increases. A well-tuned model that has been successful at describing a wide range of proton scattering data from the HERA experiments fails to describe the observed correlations, suggesting the presence of gluon polarization effects.
The production of Z bosons associated with jets is measured in pp collisions at s=13TeV with data recorded with the CMS experiment at the LHC corresponding to an integrated luminosity of 36.3fb-1. The multiplicity of jets with transverse momentum pT>30GeV is measured for different regions of the Z boson's pT(Z), from lower than 10GeV to higher than 100GeV. The azimuthal correlation Δϕ between the Z boson and the leading jet, as well as the correlations between the two leading jets are measured in three regions of pT(Z). The measurements are compared with several predictions at leading and next-to-leading orders, interfaced with parton showers. Predictions based on transverse-momentum dependent parton distributions and corresponding parton showers give a good description of the measurement in the regions where multiple parton interactions and higher jet multiplicities are not important. The effects of multiple parton interactions are shown to be important to correctly describe the measured spectra in the low pT(Z) regions.
A measurement for inclusive 2- and 3-jet events of the azimuthal correlation between the two jets with the largest transverse momenta, Δ ϕ 12 , is presented. The measurement considers events where the two leading jets are nearly collinear ("back-to-back") in the transverse plane and is performed for several ranges of the leading jet transverse momentum. Proton-proton collision data collected with the CMS experiment at a center-of-mass energy of 13 Te and corresponding to an integrated luminosity of 35.9 fb - 1 are used. Predictions based on calculations using matrix elements at leading-order and next-to-leading-order accuracy in perturbative quantum chromodynamics supplemented with leading-log parton showers and hadronization are generally in agreement with the measurements. Discrepancies between the measurement and theoretical predictions are as large as 15%, mainly in the region 177 ∘ < Δ ϕ 12 < 180 ∘ . The 2- and 3-jet measurements are not simultaneously described by any of models.