1,199 research outputs found
Smoothing nodal Calabi-Yau n-folds
Let X be an n-dimensional Calabi-Yau with ordinary double points, where n is
odd. Friedman showed that for n=3 the existence of a smoothing of X implies a
specific type of relation between homology classes on a resolution of X. (The
converse is also true, due to work of Friedman, Kawamata and Tian.)
We sketch a more topological proof of this result, and then extend it to
higher dimensions. For n>3 the "Yukawa product" on the middle dimensional
(co)homology plays an unexpected role. We also discuss a converse, proving it
for nodal Calabi-Yau hypersurfaces in projective space.Comment: Included missing torsion in Lemma 2.5. Results unchanged. 20 page
On a Penrose Inequality with Charge
We construct a time-symmetric asymptotically flat initial data set to the
Einstein-Maxwell Equations which satisfies the inequality: m - 1/2(R + Q^2/R) <
0, where m is the total mass, R=sqrt(A/4) is the area radius of the outermost
horizon and Q is the total charge. This yields a counter-example to a natural
extension of the Penrose Inequality to charged black holes.Comment: Minor revision: some typos; author's address updated; bibliographical
reference added; journal information: to appear in Comm. Math. Phy
Predictors of Increases in Alcohol Problems and Alcohol Use Disorders in Offspring in the San Diego Prospective Study.
BackgroundThe 35-year-long San Diego Prospective Study documented 2-fold increases in alcohol problems and alcohol use disorders (AUDs) in young-adult drinking offspring compared to rates in their fathers, the original probands. The current analyses use the same interviews and questionnaires at about the same age in members of the 2 generations to explore multiple potential contributors to the generational differences in adverse alcohol outcomes.MethodsUsing data from recent offspring interviews, multiple cross-generation differences in characteristics potentially related to alcohol problems were evaluated in 3 steps: first through direct comparisons across probands and offspring at about age 30; second by backward linear regression analyses of predictors of alcohol problems within each generation; and finally third through R-based bootstrapped linear regressions of differences in alcohol problems in randomly matched probands and offspring.ResultsThe analyses across the analytical approaches revealed 3 consistent predictors of higher alcohol problems in the second generation. These included the following: (i) a more robust relationship to alcohol problems for offspring with a low level of response to alcohol; (ii) higher offspring values for alcohol expectancies; and (iii) higher offspring impulsivity.ConclusionsThe availability of data across generations offered a unique perspective for studying characteristics that may have contributed to a general finding in the literature of substantial increases in alcohol problems and AUDs in recent generations. If replicated, these results could suggest approaches to be used by parents, healthcare workers, insurance companies, and industry in their efforts to mitigate the increasing rates of alcohol problems in younger generations
Interactions of Brown Bears, Ursus arctos, and Gray Wolves, Canis lupus, at Katmai National Park and Preserve, Alaska
We describe several encounters between Brown Bears (Ursus arctos) and Gray Wolves (Canis lupus) that were observed at Katmai National Park and Preserve in southwest Alaska. Katmai Brown Bears and Gray Wolves were observed interacting in a variety of behavioral modes that ranged from agonistic to tolerant. These observations provide additional insight regarding the behavioral plasticity associated with bear-wolf interactions
Innovative Technology for High Performance and Mass Participation Sport
The chapter analyzes technological innovations used in high-level sport and how mass participants have and will benefit from these advancements. The authors discuss progressive practices of different successful sporting nations. The chapter debriefs high-performance facility development and utilization practices, as well as examples of modern equipment and technology being applied in multiple high-performance athlete service areas, such as general fitness, sport-specific training, restoration, nutrition, medicine, and psychology. This section also emphasizes examples of national and local high-performance technology practices for enhancing mass participation, such as evolving networks of comprehensive multisport training centers available for nurturing every possible age and socioeconomic group. Finally, suggestions are made to provide communities, in partnership with universities or local military installations, with recreation and sport technologies which are free or affordable for all, including instructions enabling everyone to utilize and enjoy the new technologies
Bloch bundles, Marzari-Vanderbilt functional and maximally localized Wannier functions
We consider a periodic Schroedinger operator and the composite Wannier
functions corresponding to a relevant family of its Bloch bands, separated by a
gap from the rest of the spectrum. We study the associated localization
functional introduced by Marzari and Vanderbilt, and we prove some results
about the existence and exponential localization of its minimizers, in
dimension d < 4. The proof exploits ideas and methods from the theory of
harmonic maps between Riemannian manifolds.Comment: 37 pages, no figures. V2: the appendix has been completely rewritten.
V3: final version, to appear in Commun. Math. Physic
The treatment experiences of people living with ileostomies: an interpretative phenomenological analysis
AIMS: To explore treatment and healthcare experiences of people living with ileostomies, so nurses can build on best practice whilst caring for these patients.
Background Ileostomies, in which the small intestine is re-directed out of a stoma in the abdominal wall so waste is collected using a bag, are used to treat conditions including Inflammatory Bowel Disease. Existing research suggests that although life with a stoma can be challenging, ileostomy patients are largely supported by multi-disciplinary teams. However, more research is needed to understand the nuances of these relationships and experiences of treatment, with a view to improving clinical care.
DESIGN: Participants took part in semi-structured interviews consisting of open ended questions about their experiences of life with an ileostomy and their treatments and time in hospital. Points of interest were followed up. Data were collected between July and December of 2014.
METHODS: The qualitative method Interpretative Phenomenological Analysis was used to analyse interviews with 21 people living with ileostomies.
FINDINGS: We present findings from two clinical themes: Issues around treatment and Relationships with multi-disciplinary teams. Surgical complications were common, and several participants reported concerns about addiction to painkillers. Varying attitudes were found around reversal surgery. Many reported experiencing distressing, dehumanising care, whilst some felt supported by excellent healthcare providers.
CONCLUSION: People living with ileostomies have a very mixed experience of multi-disciplinary teams and treatments, and much could be done to support them more fully. For example, more information about ileostomies could be given to patients and more training given to nurses around stomas
Spontaneous mutation accumulation in multiple strains of the green alga, Chlamydomonas reinhardtii
Estimates of mutational parameters, such as the average fitness effect of a new mutation and the rate at which new genetic variation for fitness is created by mutation, are important for the understanding of many biological processes. However, the causes of interspecific variation in mutational parameters and the extent to which they vary within species remain largely unknown. We maintained multiple strains of the unicellular eukaryote Chlamydomonas reinhardtii, for approximately 1000 generations under relaxed selection by transferring a single cell every ∼10 generations. Mean fitness of the lines tended to decline with generations of mutation accumulation whereas mutational variance increased. We did not find any evidence for differences among strains in any of the mutational parameters estimated. The overall change in mean fitness per cell division and rate of input of mutational variance per cell division were more similar to values observed in multicellular organisms than to those in other single-celled microbes. However, after taking into account differences in genome size among species, estimates from multicellular organisms and microbes, including our new estimates from C. reinhardtii, become substantially more similar. Thus, we suggest that variation in genome size is an important determinant of interspecific variation in mutational parameters
Promotion of access to essential medicines for Non-Communicable Diseases: Practical implications of the UN Political Declaration
Access to medicines and vaccines to prevent and treat non-communicable diseases (NCDs) is unacceptably low worldwide. In the 2011 UN political declaration on the prevention and control of NCDs, heads of government made several commitments related to access to essential medicines, technologies, and vaccines for such diseases. 30 years of experience with policies for essential medicines and 10 years of scaling up of HIV treatment have provided the knowledge needed to address barriers to long-term effective treatment and prevention of NCDs. More medicines can be acquired within existing budgets with efficient selection, procurement, and use of generic medicines. Furthermore, low-income and middle-income countries need to increase mobilisation of domestic resources to cater for the many patients with NCDs who do not have access to treatment. Existing initiatives for HIV treatment offer useful lessons that can enhance access to pharmaceutical management of NCDs and improve adherence to long-term treatment of chronic illness; policy makers should also address unacceptable inequities in access to controlled opioid analgesics. In addition to off-patent medicines, governments can promote access to new and future on-patent medicinal products through coherent and equitable health and trade policies, particularly those for intellectual property. Frequent conflicts of interest need to be identified and managed, and indicators and targets for access to NCD medicines should be used to monitor progress. Only with these approaches can a difference be made to the lives of hundreds of millions of current and future patients with NCDs
Pathological considerations in replacement cardiac valves
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30262/1/0000663.pd
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