2,877 research outputs found
Dr Pepper Snapple Group: Fighting to Prosper In a Highly Competitive Market
Since its separation from the food giant Cadbury Schweppes, Dr Pepper Snapple Group has experienced successes such as the turnaround of the Snapple brand and growth in demand for some of its popular brands. However, the company is still a distant third in an incredibly competitive industry. How can the company achieve continued success in the shadows of Coca Cola and PepsiCo
An approach to permutation symmetry for the electroweak theory
The form of the leptonic mixing matrix emerging from experiment has, in the
last few years, generated a lot of interest in the so-called tribimaximal type.
This form may be naturally associated with the possibility of a discrete
permutation symmetry () among the three generations. However, trying to
implement this attractive symmetry has resulted in some problems and it seems
to have fallen out of favor. We suggest an approach in which the holds to
first approximation, somewhat in the manner of the old SU(3) flavor symmetry of
the three flavor quark model. It is shown that in the case of the neutrino
sector, a presently large experimentally allowed region can be fairly well
described in this first approximation.
We briefly discuss the nature of the perturbations which are the analogs of
the Gell-Mann Okubo perturbations but confine our attention for the most part
to the invariant model. We postulate that the invariant mass
spectrum consists of non zero masses for the and zero masses for
the other charged fermions but approximately degenerate masses for the three
neutrinos. The mixing matrices are assumed to be trivial for the charged
fermions but of tribimaximal type for the neutrinos in the first approximation.
It is shown that this can be implemented by allowing complex entries for the
mass matrix and spontaneous breakdown of the invariance of the
Lagrangian.Comment: 24 pages, 1 figure, minor corrections and acknowledgment added. To
appear in IJM
Outsourcing Mutual Fund Management: Firm Boundaries, Incentives and Performance
This paper investigates the effects of managerial outsourcing on the incentives and performance of mutual funds. We document that mutual fund families outsource the management of a significant fraction of their funds to unaffiliated advisory firms. Funds managed externally significantly under-perform those ran internally. To establish the causality of this relationship, we instrument for whether a fund is outsourced and find similar estimates. We hypothesize that contractual externalities due to firm boundaries make it more difficult to extract performance from an outsourced relationship. We verify two auxiliary predictions of this hypothesis: compared to counterparts ran internally, an outsourced fund faces higher-powered incentives in that they are more likely to be closed due to poor performance or excessive risk-taking, and an outsourced fund takes less risk in response
Public health and economic costs of investigating a suspected outbreak of Legionnaires' disease.
This paper provides one of the first assessments of the burden of both the public health investigation and the economic costs associated with an apparent outbreak of Legionnaires' disease (LD) in South East London. In addition to epidemiological, microbiological and environmental investigations, we collected data on the staff time and resources committed by the 11 main organizations responsible for managing the outbreak. Of the overall estimated costs of 455,856 pounds, only 14% (64,264 pounds) was spent on investigation and control of the outbreak compared with 86% (391,592 pounds) spent on the hospital treatment of the patients. The time and money spent on public health services in this investigation appear to represent good value for money considering the potential costs of a major outbreak, including the high case-fatality rate in LD generally and the high health-care costs. Further research is needed to determine optimum strategies for the cost-effective use of health system resources in investigations of LD. Whether the threshold for investigation of cases should be based on observed incidence rates or the cost-effectiveness of investigations, or both, should be debated further
Adjunctive interferon-Îł immunotherapy for the treatment of HIV-associated cryptococcal meningitis: a randomized controlled trial.
BACKGROUND: Interferon-gamma (IFNÎł) is of key importance in the immune response to Cryptococcus neoformans. Mortality related to cryptococcal meningitis remains high, and novel treatment strategies are needed. We performed a randomized controlled trial to determine whether addition of IFNÎł to standard therapy increased the rate of clearance of cryptococcal infection in HIV-associated cryptococcal meningitis. METHODS: Patients were randomized to amphotericin B 1âmg/kg per day and 5FC 100âmg/kg per day for 2 weeks (standard therapy), standard therapy and IFNÎł1b 100âÎŒg days 1 and 3 (IFNÎł two doses), or standard therapy and IFNÎł1b 100âÎŒg days 1, 3, 5, 8, 10 and 12 (IFNÎł six doses). Primary outcome was rate of clearance of cryptococcus from the cerebrospinal fluid (CSF) (early fungicidal activity, EFA) calculated from serial quantitative cultures, previously shown to be independently associated with survival. RESULTS: Rate of fungal clearance was significantly faster in IFNÎł containing groups than with standard treatment. Mean EFA [log colony forming unit (CFU)/ml per day] was -0.49 with standard treatment, -0.64 with IFNÎł two doses, and -0.64 with IFNÎł six doses. Difference in EFA was -0.15 [confidence interval (95% CI) -0.02 to -0.27, P=0.02] between standard treatment and IFNÎł two doses, and -0.15 (95% CI -0.05 to -0.26, P=0.006) between standard treatment and IFNÎł six doses. Mortality was 16% (14/88) at 2 weeks and 31% (27/87) at 10 weeks, with no significant difference between groups. All treatments were well tolerated. CONCLUSION: Addition of short-course IFNÎł to standard treatment significantly increased the rate of clearance of cryptococcal infection from the CSF, and was not associated with any increase in adverse events. Two doses of IFNÎł are as effective as six doses
Symptomatic relapse of HIV-associated cryptococcal meningitis in South Africa: the role of inadequate secondary prophylaxis.
OBJECTIVES: Cryptococcal meningitis is the commonest cause of adult meningitis in Southern Africa. A sizeable proportion of this disease burden is thought to be due to symptomatic relapse of previously treated infection. We carried out a study to examine the contribution of inadequate secondary fluconazole prophylaxis to symptomatic relapses of cryptococcal meningitis. DESIGN: A prospective observational study of patients presenting with laboratory-confirmed symptomatic relapse of HIV-associated cryptococcal meningitis between January 2007 and December 2008 at GF Jooste Hospital, a public sector adult referral hospital in Cape Town. OUTCOME MEASURES: Relapse episodes were categorized into 1) patients not taking fluconazole prophylaxis, 2) immune reconstitution inflammatory syndrome (IRIS) and 3) relapses occurring prior to ART in patients taking fluconazole. In-hospital mortality was recorded. RESULTS: There were 69 relapse episodes, accounting for 23% of all cases of cryptococcal meningitis. 43%(n=30) of relapse episodes were in patients not taking fluconazole prophylaxis, 45%(31) were due to IRIS and 12%(8) were in patients pre-ART taking fluconazole. Patients developing relapse due to inadequate secondary prophylaxis had severe disease and high in-hospital mortality (33%). Of the 30 patients not taking fluconazole, 47% (14) had not been prescribed secondary prophylaxis by their healthcare providers. Importantly, we documented no relapses due to fluconazole resistance in this cohort of patients who has received amphotericin B as initial therapy. CONCLUSIONS: Large numbers of relapses of cryptococcal meningitis are due to failed prescription, dispensing, referral for or adherence to secondary fluconazole prophylaxis. Interventions to improve the use of secondary fluconazole prophylaxis are essential
Sulfite reduction in mycobacteria
Mycobacterium tuberculosis places an enormous burden on the welfare of humanity. Its ability to grow and its pathogenicity are linked to sulfur metabolism, which is considered a fertile area for the development of antibiotics, particularly because many of the sulfur acquisition steps in the bacterium are not found in the host. Sulfite reduction is one such mycobacterium-specific step and is the central focus of this paper. Sulfite reduction in Mycobacterium smegmatis was investigated using a combination of deletion mutagenesis, metabolite screening, complementation, and enzymology. The initial rate parameters for the purified sulfite reductase from M. tuberculosis were determined under strict anaerobic conditions [kcat = 1.0 (±0.1) electron consumed per second, and Km(SO3â2) = 27 (±1) ÎŒM], and the enzyme exhibits no detectible turnover of nitrite, which need not be the case in the sulfite/nitrite reductase family. Deletion of sulfite reductase (sirA, originally misannotated nirA) reveals that it is essential for growth on sulfate or sulfite as the sole sulfur source and, further, that the nitrite-reducing activities of the cell are incapable of reducing sulfite at a rate sufficient to allow growth. Like their nitrite reductase counterparts, sulfite reductases require a siroheme cofactor for catalysis. Rv2393 (renamed che1) resides in the sulfur reduction operon and is shown for the first time to encode a ferrochelatase, a catalyst that inserts Fe2+ into siroheme. Deletion of che1 causes cells to grow slowly on metabolites that require sulfite reductase activity. This slow-growth phenotype was ameliorated by optimizing growth conditions for nitrite assimilation, suggesting that nitrogen and sulfur assimilation overlap at the point of ferrochelatase synthesis and delivery
Symptomatic relapse of HIV-associated cryptococcal meningitis in South Africa: The role of inadequate secondary prophylaxis
Objectives. Cryptococcal meningitis is the most common cause of adult meningitis in southern Africa. Much of this disease burden is thought to be due to symptomatic relapse of previously treated infection. We studied the contribution of inadequate secondary fluconazole prophylaxis to symptomatic relapses of cryptococcal meningitis. Design. A prospective observational study of patients presenting with laboratory-confirmed symptomatic relapse of HIV-associated cryptococcal meningitis between January 2007 and December 2008 at GF Jooste Hospital, a public sector adult referral hospital in Cape Town. Outcome measures. Relapse episodes were categorised into: (i) patients not taking fluconazole prophylaxis; (ii) immune reconstitution inflammatory syndrome (IRIS); and (iii) relapses occurring prior to ART in patients taking fluconazole. In-hospital mortality was recorded. Results. There were 69 relapse episodes, accounting for 23% of all cases of cryptococcal meningitis; 43% (N=30) of relapse episodes were in patients not receiving fluconazole prophylaxis, 45% (N=31) were due to IRIS, and 12% (N=8) were in patients pre-ART taking fluconazole. Patients developing relapse due to inadequate secondary prophylaxis had severe disease and high in-hospital mortality (33%). Of the 30 patients not taking fluconazole, 47% (N=14) had not been prescribed secondary prophylaxis by their health care providers. We documented no relapses due to fluconazole resistance in these patients who received amphotericin B as initial therapy. Conclusions. A large number of relapses of cryptococcal meningitis are due to failed prescription, dispensing and referral for or adherence to secondary fluconazole prophylaxis. Interventions to improve the use of secondary fluconazole prophylaxis are essential
Mechanism of Lysine 48 Selectivity during Polyubiquitin Chain Formation by the Ube2R1/2 Ubiquitin-Conjugating Enzyme
Lysine selectivity is of critical importance during polyubiquitin chain formation because the identity of the lysine controls the biological outcome. Ubiquitins are covalently linked in polyubiquitin chains through one of seven lysine residues on its surface and the C terminus of adjacent protomers. Lys 48-linked polyubiquitin chains signal for protein degradation; however, the structural basis for Lys 48 selectivity remains largely unknown. The ubiquitin-conjugating enzyme Ube2R1/2 has exquisite specificity for Lys 48, and computational docking of Ube2R1/2 and ubiquitin predicts that Lys 48 is guided to the active site through a key electrostatic interaction between Arg 54 on ubiquitin and Asp 143 on Ube2R1/2. The validity of this interaction was confirmed through biochemical experiments. Since structural examples involving Arg 54 in protein-ubiquitin complexes are exceedingly rare, these results provide additional insight into how ubiquitin-protein complexes can be stabilized. We discuss how these findings relate to how other ubiquitin-conjugating enzymes direct the lysine specificity of polyubiquitin chains
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