Novel QCD Phenomenology

I review a number of topics where conventional wisdom in hadron physics has been challenged. For example, hadrons can be produced at large transverse momentum directly within a hard higher-twist QCD subprocess, rather than from jet fragmentation. Such "direct" processes can explain the deviations from perturbative QCD predictions in measurements of inclusive hadron cross sections at fixed x_T= 2p_T/\sqrt s, as well as the "baryon anomaly", the anomalously large proton-to-pion ratio seen in high centrality heavy ion collisions. Initial-state and final-state interactions of the struck quark lead to Bjorken-scaling single-spin asymmetries, diffractive deep inelastic scattering, the breakdown of the Lam-Tung relation in Drell-Yan reactions, as well as nuclear shadowing and antishadowing. The Gribov-Glauber theory predicts that antishadowing of nuclear structure functions is not universal, but instead depends on the flavor quantum numbers of each quark and antiquark, thus explaining the anomalous nuclear dependence measured in deep-inelastic neutrino scattering. One cannot attribute such phenomena to the structure of the hadron or nucleus itself. It is thus important to distinguish "static" structure functions computed from the square of the target light-front wavefunctions, versus "dynamical" structure functions which include the effects of the final-state rescattering of the struck quark. The importance of the J=0 photon-quark QCD contact interaction in deeply virtual Compton scattering is emphasized. The scheme-independent BLM method for setting the renormalization scale is discussed. Eliminating the renormalization scale ambiguity greatly improves the precision of QCD predictions and increases the sensitivity of searches for new physics at the LHC. Other novel features of QCD are discussed, including the consequences of confinement for quark and gluon condensates.Comment: Invited talk, presented at the Gribov-80 Memorial Workshop on Quantum Chromodynamics and Beyond, May, 2010, Abdus Salam International Centre for Theoretical Physics. Trieste, Ital

New Perspectives for QCD Physics at the LHC

I review a number of topics where conventional wisdom relevant to hadron physics at the LHC has been challenged. For example, the initial-state and final-state interactions of the quarks and gluons entering perturbative QCD hard-scattering subprocesses lead to the breakdown of traditional concepts of factorization and universality for transverse-momentum-dependent observables at leading twist. These soft-gluon rescattering effect produce single-spin asymmetries, the breakdown of the Lam-Tung relation in Drell-Yan reactions, as well as diffractive deep inelastic scattering, The antishadowing of nuclear structure functions is predicted to depend on the flavor quantum numbers of each quark and antiquark. Isolated hadrons can be produced at large transverse momentum directly within a hard higher-twist QCD subprocess, rather than from jet fragmentation, even at the LHC. Such "direct" processes can explain the observed deviations from pQCD predictions of the power-law fall-off of inclusive hadron cross sections as well as the "baryon anomaly" seen in high-centrality heavy-ion collisions at RHIC. The intrinsic charm contribution to the proton structure function at high x can explain the large rate for high p_T photon plus charm-jet events observed at the Tevatron and imply a large production rate for charm and bottom jets at high p_T at the LHC, as well as a novel mechanism for Higgs and Z^0 production at high x_F. The light-front wavefunctions derived in AdS/QCD can be used to calculate jet hadronization at the amplitude level. The elimination of the renormalization scale ambiguity for the QCD coupling using the scheme-independent BLM method will increase the sensitivity of searches for new physics at the LHC. The implications of "in-hadron condensates" for the QCD contribution to the cosmological constant are also discussed.Comment: Invited talk, presented at the 5th Workshop on High P_T Physics at the LHC held at the Instituto de Ciencias Nucleares of the Universidad National Automata de Mexico in Mexico City, September 27-October 1, 201

Phytoseiid mites of Colombia (Acarina: Phytoseiidae).

This is the second report of the phytoseiids of Colombia. A new genus and species, Quadromalus colombiensis and Euseius ricinus n.sp. are described, bringing the total to 17 species of phytoseiids for Colombia

Accessing the distribution of linearly polarized gluons in unpolarized hadrons

Gluons inside unpolarized hadrons can be linearly polarized provided they have a nonzero transverse momentum. The simplest and theoretically safest way to probe this distribution of linearly polarized gluons is through cos(2 phi) asymmetries in heavy quark pair or dijet production in electron-hadron collisions. Future Electron-Ion Collider (EIC) or Large Hadron electron Collider (LHeC) experiments are ideally suited for this purpose. Here we estimate the maximum asymmetries for EIC kinematics.Comment: 4 pages, 2 figures, to appear in the proceedings of the XIX International Workshop on Deep Inelastic Scattering and Related Subjects (DIS 2011), Newport News, VA, USA, 11-15 April 201

How do Typically Developing Deaf Children and Deaf Children with Autism Spectrum Disorder Use the Face When Comprehending Emotional Facial Expressions in British Sign Language?

Facial expressions in sign language carry a variety of communicative features. While emotion can modulate a spoken utterance through changes in intonation, duration and intensity, in sign language specific facial expressions presented concurrently with a manual sign perform this function. When deaf adult signers cannot see facial features, their ability to judge emotion in a signed utterance is impaired (Reilly et al. in Sign Lang Stud 75:113-118, 1992). We examined the role of the face in the comprehension of emotion in sign language in a group of typically developing (TD) deaf children and in a group of deaf children with autism spectrum disorder (ASD). We replicated Reilly et al.'s (Sign Lang Stud 75:113-118, 1992) adult results in the TD deaf signing children, confirming the importance of the face in understanding emotion in sign language. The ASD group performed more poorly on the emotion recognition task than the TD children. The deaf children with ASD showed a deficit in emotion recognition during sign language processing analogous to the deficit in vocal emotion recognition that has been observed in hearing children with ASD

Narrative skills in deaf children who use spoken English: Dissociations between macro and microstructural devices

Previous research has highlighted that deaf children acquiring spoken English have difficulties in narrative development relative to their hearing peers both in terms of macro-structure and with micro-structural devices. The majority of previous research focused on narrative tasks designed for hearing children that depend on good receptive language skills. The current study compared narratives of 6 to 11-year-old deaf children who use spoken English (N = 59) with matched for age and non-verbal intelligence hearing peers. To examine the role of general language abilities, single word vocabulary was also assessed. Narratives were elicited by the retelling of a story presented non-verbally in video format. Results showed that deaf and hearing children had equivalent macro-structure skills, but the deaf group showed poorer performance on micro-structural components. Furthermore, the deaf group gave less detailed responses to inferencing probe questions indicating poorer understanding of the story’s underlying message. For deaf children, micro-level devices most strongly correlated with the vocabulary measure. These findings suggest that deaf children, despite spoken language delays, are able to convey the main elements of content and structure in narrative but have greater difficulty in using grammatical devices more dependent on finer linguistic and pragmatic skills

Timing of elective surgery and risk assessment after SARS-CoV-2 infection: 2023 update

Guidance for the timing of surgery following SARS-CoV-2 infection needed reassessment given widespread vaccination, less virulent variants, contemporary evidence and a need to increase access to safe surgery. We, therefore, updated previous recommendations to assist policymakers, administrative staff, clinicians and, most importantly, patients. Patients who develop symptoms of SARS-CoV-2 infection within 7 weeks of planned surgery, including on the day of surgery, should be screened for SARS-CoV-2. Elective surgery should not usually be undertaken within 2 weeks of diagnosis of SARS-CoV-2 infection. For patients who have recovered from SARS-CoV-2 infection and who are low risk or having low-risk surgery, most elective surgery can proceed 2 weeks following a SARS-CoV-2 positive test. For patients who are not low risk or having anything other than low-risk surgery between 2 and 7 weeks following infection, an individual risk assessment must be performed. This should consider: patient factors (age; comorbid and functional status); infection factors (severity; ongoing symptoms; vaccination); and surgical factors (clinical priority; risk of disease progression; grade of surgery). This assessment should include the use of an objective and validated risk prediction tool and shared decision-making, taking into account the patient's own attitude to risk. In most circumstances, surgery should proceed unless risk assessment indicates that the risk of proceeding exceeds the risk of delay. There is currently no evidence to support delaying surgery beyond 7 weeks for patients who have fully recovered from or have had mild SARS-CoV-2 infection

Signing with the Face: Emotional Expression in Narrative Production in Deaf Children with Autism Spectrum Disorder

This study examined facial expressions produced during a British Sign Language (BSL) narrative task (Herman et al., International Journal of Language and Communication Disorders 49(3):343–353, 2014) by typically developing deaf children and deaf children with autism spectrum disorder. The children produced BSL versions of a video story in which two children are seen to enact a language-free scenario where one tricks the other. This task encourages elicitation of facial acts signalling intention and emotion, since the protagonists showed a range of such expressions during the events portrayed. Results showed that typically developing deaf children produced facial expressions which closely aligned with native adult signers’ BSL narrative versions of the task. Children with ASD produced fewer targeted expressions and showed qualitative differences in the facial actions that they produced

New biphenyl iminium salt catalysts for highly enantioselective asymmetric epoxidation: role of additional substitution and dihedral angle

New biaryl iminium salt catalysts for enantioselective alkene epoxidation containing additional substitution in the heterocyclic ring are reported. The effects upon conformation and enantioselectivity of this additional substitution, and the influence of dihedral angle in these systems, has been investigated using a synthetic approach supported by density functional theory. Enantioselectivities of up to 97% ee were observed

Timing of elective surgery and risk assessment after SARS‐CoV ‐2 infection:an update: A multidisciplinary consensus statement on behalf of the Association of Anaesthetists, Centre for Perioperative Care, Federation of Surgical Specialty Associations, Royal College of Anaesthetists, Royal College of Surgeons of England

The impact of vaccination and new SARS‐CoV‐2 variants on peri‐operative outcomes is unclear. We aimed to update previously published consensus recommendations on timing of elective surgery after SARS‐CoV‐2 infection to assist policymakers, administrative staff, clinicians and patients. The guidance remains that patients should avoid elective surgery within 7 weeks of infection, unless the benefits of doing so exceed the risk of waiting. We recommend individualised multidisciplinary risk assessment for patients requiring elective surgery within 7 weeks of SARS‐CoV‐2 infection. This should include baseline mortality risk calculation and assessment of risk modifiers (patient factors; SARS‐CoV‐2 infection; surgical factors). Asymptomatic SARS‐CoV‐2 infection with previous variants increased peri‐operative mortality risk three‐fold throughout the 6 weeks after infection, and assumptions that asymptomatic or mildly symptomatic omicron SARS‐CoV‐2 infection does not add risk are currently unfounded. Patients with persistent symptoms and those with moderate‐to‐severe COVID‐19 may require a longer delay than 7 weeks. Elective surgery should not take place within 10 days of diagnosis of SARS‐CoV‐2 infection, predominantly because the patient may be infectious, which is a risk to surgical pathways, staff and other patients. We now emphasise that timing of surgery should include the assessment of baseline and increased risk, optimising vaccination and functional status, and shared decision‐making. While these recommendations focus on the omicron variant and current evidence, the principles may also be of relevance to future variants. As further data emerge, these recommendations may be revised