Sequences of Willmore surfaces

In this paper we develop the theory of Willmore sequences for Willmore surfaces in the 4-sphere. We show that under appropriate conditions this sequence has to terminate. In this case the Willmore surface either is the twistor projection of a holomorphic curve into complex projective space or the inversion of a minimal surface with planar ends in 4-space. These results give a unified explanation of previous work on the characterization of Willmore spheres and Willmore tori with non-trivial normal bundles by various authors.Comment: 10 page

Hamiltonization of Nonholonomic Systems and the Inverse Problem of the Calculus of Variations

We introduce a method which allows one to recover the equations of motion of a class of nonholonomic systems by finding instead an unconstrained Hamiltonian system on the full phase space, and to restrict the resulting canonical equations to an appropriate submanifold of phase space. We focus first on the Lagrangian picture of the method and deduce the corresponding Hamiltonian from the Legendre transformation. We illustrate the method with several examples and we discuss its relationship to the Pontryagin maximum principle.Comment: 23 pages, accepted for publication in Rep. Math. Phy

Constrained Willmore Surfaces

Constrained Willmore surfaces are conformal immersions of Riemann surfaces that are critical points of the Willmore energy $W=\int H^2$ under compactly supported infinitesimal conformal variations. Examples include all constant mean curvature surfaces in space forms. In this paper we investigate more generally the critical points of arbitrary geometric functionals on the space of immersions under the constraint that the admissible variations infinitesimally preserve the conformal structure. Besides constrained Willmore surfaces we discuss in some detail examples of constrained minimal and volume critical surfaces, the critical points of the area and enclosed volume functional under the conformal constraint.Comment: 17 pages, 8 figures; v2: Hopf tori added as an example, minor changes in presentation, numbering changed; v3: new abstract and appendix, several changes in presentatio

Despite NAIS concerns electronic identification use by cow-calf producers is increasing

The proposed U.S. National Animal Identification System has generated concerns among producers relative to implementation of the system. Many of these concerns stem from the USDA’s Bovine Identification Working Group’s recommendations to use electronic Identification Plan Bovine Working Group has recommended radio frequency identification as the technology to individually identify cattle. Understanding and implementing an electronic identification system for cow-calf producers is believed to be one of the greatest challenges of implementing the National Animal Identification System

Activities, function, and health-related quality of life (HRQOL) of older adults with cancer

Objective This study aims to (1) describe the activities, function, and health-related quality of life (HRQOL) of a large sample of older adults (age ≥ 65) with cancer, (2) identify the associations with demographics, cancer type, comorbid conditions, and ability to participate in activities and functional status. Materials and Methods The Health Registry/Cancer Survivorship Cohort is an institutional database designed to aid cancer survivorship research. The registry includes three measures of patient-reported HRQOL: FACT-G and PROMIS® Global measures for physical and mental health. Other measures included in the registry are cancer type, date from diagnosis, number of comorbid conditions and specific conditions and their limitations in daily activity, and self-reported daily activity/function. Results Our sample consists of 768 older adults with cancer, mean age 72 years, 60% female, and 90% White. Mean scores for HRQOL: FACT-G (85, range: 25–108), PROMIS-physical (48, range: 16–67) and, PROMIS-mental (51, range: 21–67). In multivariable models, Black race, one or more comorbid conditions, and Gastrointestinal cancer (p < .05), and patient- reported decreased levels of activities/function were all independently associated with poor HRQOL (p < .0001). Conclusions Older Black adults with cancer, those that have high comorbidity burden, with gastrointestinal cancers and those that report decreased ability to participate in daily activities/function reported poorer HRQOL. As geriatric oncology moves towards trying to identify who may need supportive services, this study demonstrated that a one question patient-reported level of activities and functional ability were independently associated with physical, mental, and cancer-specific HRQOL

Orientifolds of K3 and Calabi-Yau Manifolds with Intersecting D-branes

We investigate orientifolds of type II string theory on K3 and Calabi-Yau 3-folds with intersecting D-branes wrapping special Lagrangian cycles. We determine quite generically the chiral massless spectrum in terms of topological invariants and discuss both orbifold examples and algebraic realizations in detail. Intriguingly, the developed techniques provide an elegant way to figure out the chiral sector of orientifold models without computing any explicit string partition function. As a new example we derive a non-supersymmetric Standard-like Model from an orientifold of type IIA on the quintic Calabi-Yau 3-fold with wrapped D6-branes. In the case of supersymmetric intersecting brane models on Calabi-Yau manifolds we discuss the D-term and F-term potentials, the effective gauge couplings and the Green-Schwarz mechanism. The mirror symmetric formulation of this construction is provided within type IIB theory. We finally include a short discussion about the lift of these models from type IIB on K3 to F-theory and from type IIA on Calabi-Yau 3-folds to M-theory on G_2 manifolds.Comment: 82 pages, harvmac, 5 figures. v2: references added. v3: T^6 orientifold corrected, JHEP versio

D-Brane Probes of Special Holonomy Manifolds

Using D2-brane probes, we study various properties of M-theory on singular, non-compact manifolds of G_2 and Spin(7) holonomy. We derive mirror pairs of N=1 supersymmetric three-dimensional gauge theories, and apply this technique to realize exceptional holonomy manifolds as both Coulomb and Higgs branches of the D2-brane world-volume theory. We derive a ``G_2 quotient construction'' of non-compact manifolds which admit a metric of G_2 holonomy. We further discuss the moduli space of such manifolds, including the structure of geometrical transitions in each case. For completeness, we also include familiar examples of manifolds with SU(3) and Sp(2) holonomy, where some of the new ideas are clarified and tested.Comment: 79 pages, Late

Non-Abelian Vortices, Super-Yang-Mills Theory and Spin(7)-Instantons

We consider a complex vector bundle E endowed with a connection A over the eight-dimensional manifold R^2 x G/H, where G/H = SU(3)/U(1)xU(1) is a homogeneous space provided with a never integrable almost complex structure and a family of SU(3)-structures. We establish an equivalence between G-invariant solutions A of the Spin(7)-instanton equations on R^2 x G/H and general solutions of non-Abelian coupled vortex equations on R^2. These vortices are BPS solitons in a d=4 gauge theory obtained from N=1 supersymmetric Yang-Mills theory in ten dimensions compactified on the coset space G/H with an SU(3)-structure. The novelty of the obtained vortex equations lies in the fact that Higgs fields, defining morphisms of vector bundles over R^2, are not holomorphic in the generic case. Finally, we introduce BPS vortex equations in N=4 super Yang-Mills theory and show that they have the same feature.Comment: 14 pages; v2: typos fixed, published versio

Perinatal morbidity and health utilization among mothers of medically fragile infants

Objective: To determine the burden of perinatal morbidity among mothers of medically fragile infants. Study design: We conducted a retrospective cohort study of 6849 mothers who delivered liveborn infants at a quaternary care hospital during a two-year period. We compared mothers of well babies with mothers of infants admitted to the Neonatal Intensive Care Unit (NICU), and we used logistic regression to model predictors of postpartum acute care utilization among NICU mothers. Results: Rates of obstetric morbidity were highest for mothers of infants staying ≥72 h in the NICU; 54.2% underwent cesarean birth, 7.5% experienced severe maternal morbidity, and 6.6% required a blood transfusion. Factors independently associated with postpartum acute care use included gestational age 38 °C and receiving psychiatric medication during the birth hospitalization. Conclusion: Focused support for mothers of NICU infants has the potential to reduce maternal morbidity and improve health

Older Adults with Cancer: A Randomized Controlled Trial of Occupational and Physical Therapy

OBJECTIVES: The impact of occupational therapy (OT) and physical therapy (PT) on functional outcomes in older adults with cancer is unknown. DESIGN: Two-arm single-institution randomized controlled trial of outpatient OT/PT. SETTING: Comprehensive cancer center with two off-site OT/PT clinics. PARTICIPANTS: We recruited adults 65 years and older with a recent diagnosis or recurrence of cancer within 5 years, with at least one functional limitation as identified by a geriatric assessment. Participants were randomized to OT/PT or usual care. INTERVENTION: Rehabilitation consisted of individualized OT and PT that addressed functional activities and strength/endurance needs. MEASUREMENTS: Primary outcome was functional status as measured by the Nottingham Extended Activities of Daily Living scale. Secondary outcomes were Patient-Reported Outcomes Measurement Information System-Global Mental Health (GMH) and Global Physical Health (GPH), ability to participate in Social Roles (SR), physical function, and activity expectations and self-efficacy (Possibilities for Activity Scale [PActS]). RESULTS: Among those recruited (N = 63), only 45 patients (71%) were evaluable due to loss of follow-up and/or nonreceipt of intervention. The median age was 74 years; 53% were female, and 91% were white. Overall, 30% patients had hematologic malignancies, 30% breast cancer, and 16% colorectal cancers. A total of 65% were in active treatment; 49% had stage 3 or 4 disease. At follow-up, both OT/PT (P =.02) and usual care (P =.03) groups experienced a decline in functional status. PActS scores between groups (P =.04) was significantly improved in the intervention group. GMH and SR met criteria for minimally important clinical difference favoring the intervention, but not statistical significance. Several barriers were noted in the implementation of the intervention program: recruitment, concerns about cost, distance, scheduling, and limited treatment provided. CONCLUSION: OT/PT may positively influence activity expectations and self-efficacy. Future research needs to address significant barriers to implementation to increase use of OT/PT services and access to quality care