Enhanced density fluctuations on small scales would lead to the formation of numerous dark matter minihalos, so limits on the minihalo abundance can place upper bounds on the small-scale primordial ...power spectrum. In particular, the ultracompact minihalo (UCMH), a dark matter structure hypothesized to possess a ρ∝r−9/4 density profile due to its formation at z≥1000, has been used to establish an upper bound on the primordial power spectrum at scales smaller than 2 Mpc. The extreme slope of this density profile amplifies the observational signals of UCMHs. However, we recently showed via N-body simulations that the ρ∝r−9/4 density profile does not develop in realistic formation scenarios, throwing UCMH-derived power spectrum constraints into question. Instead, minihalos develop shallower inner profiles with power-law indices between −3/2 and −1. In this paper, we expand on that result and discuss its implications. Using a model that is calibrated to simulation results and predicts halo structures in spiked power spectra based on their formation times, we calculate new upper bounds on the primordial power spectrum based on limits on the dark matter annihilation rate within the Galaxy. We find that despite assuming shallower profiles, this minihalo model actually yields stronger constraints than the previous UCMH picture owing to its inclusion of all minihalos instead of only the earliest-forming ones.
Due to climate change, plant populations experience environmental conditions to which they are not adapted. Our understanding of the next century's vegetation geography depends on the distance, ...direction, and rate at which plant distributions shift in response to a changing climate. In this study we test the sensitivity of tree range shifts (measured as the difference between seedling and mature tree ranges in climate space) to wildfire occurrence, using 74,069 Forest Inventory Analysis plots across nine states in the western United States. Wildfire significantly increased the seedling-only range displacement for 2 of the 8 tree species in which seedling-only plots were displaced from tree-plus-seedling plots in the same direction with and without recent fire. The direction of climatic displacement was consistent with that expected for warmer and drier conditions. The greater seedling-only range displacement observed across burned plots suggests that fire can accelerate climate-related range shifts and that fire and fire management will play a role in the rate of vegetation redistribution in response to climate change.
BACKGROUND: Canine T‐cell lymphoma (TCL) is clinically and histologically heterogeneous with some forms, such as T‐zone lymphoma (TZL), having an indolent course. Immunophenotyping is an important ...tool in the classification of TCL in people, and can be equally useful in dogs. HYPOTHESIS/OBJECTIVES: We hypothesized that loss of expression of the CD45 antigen is a specific diagnostic feature of TZL. ANIMALS: Twenty dogs with concurrent histology and immunophenotyping by flow cytometry were studied in depth. An additional 494 dogs diagnosed by immunophenotyping were used to characterize the population of dogs with this disease. METHODS: Lymph node biopsies from 35 dogs with TCL were classified by 2 pathologists using WHO criteria. Twenty lymph nodes were from dogs with CD45− TCL and 15 were from CD45+ TCL. The pathologists were blinded to the flow cytometry findings. Outcome information was sought for the 20 dogs with CD45− lymphoma, and population characteristics of the additional 494 dogs were described. RESULTS: All 20 CD45− cases were classified as TZL. The 15 CD45+ cases were classified as aggressive TCL and are described in an accompanying paper. TZL cases had a median survival of 637 days. Examination of 494 additional dogs diagnosed with TZL by immunophenotyping demonstrated that 40% of cases are in Golden Retrievers, are diagnosed at a median age of 10 years, and the majority have lymphadenopathy and lymphocytosis. CONCLUSIONS: TZL has unique immunophenotypic features that can be used for diagnosis.
Ultracompact minihalos (UCMHs) have emerged as a valuable probe of the primordial power spectrum of density fluctuations at small scales. UCMHs are expected to form at early times in regions with ...δρ/ρ≳10−3, and they are theorized to possess an extremely compact ρ∝r−9/4 radial density profile, which enhances their observable signatures. Nonobservation of UCMHs can thus constrain the primordial power spectrum. Using N-body simulations to study the collapse of extreme density peaks at z≃1000, we show that UCMHs forming under realistic conditions do not develop the ρ∝r−9/4 profile and instead develop either ρ∝r−3/2 or ρ∝r−1 inner density profiles depending on the shape of the power spectrum. We also demonstrate via idealized simulations that self-similarity-the absence of a scale length-is necessary to produce a halo with the ρ∝r−9/4 profile, and we argue that this implies such halos cannot form from a Gaussian primordial density field. Prior constraints derived from UCMH nonobservation must be reworked in light of this discovery. Although the shallower density profile reduces UCMH visibility, our findings reduce their signal by as little as O(10−2) while allowing later-forming halos to be considered, which suggests that new constraints could be significantly stronger.
A significant proportion of the interindividual variability in warfarin dose requirements can be explained on the basis of CYP2C9 and VKORC1 genotypes. We report the development of a novel ...pharmacogenetics–based 3–day warfarin initiation dose (ID) algorithm based on the International Warfarin Pharmacogenetics Consortium (IWPC) maintenance dose algorithm and the CYP2C9 genotype–based variance in warfarin half–life. The predictive value of the pharmacogenetics–based ID was assessed in a large cohort of 671 newly diagnosed patients with thromboembolic disorders who were about to commence anticoagulation therapy in accordance with standard induction regimens. In patients with mean international normalized ratio (INR)days 4–7 >4.0 (n = 63) after warfarin initiation, the pharmacogenetics–based ID algorithm predicted a markedly lower dose requirement (median reduction = 4.2 mg), whereas in those with mean INRdays 4–7 <2.0 (n = 145), the predicted dose requirement was very similar to that in the standard regimen. The use of a pharmacogenetics–based ID may avoid overshooting of INR in warfarin–sensitive patients without unduly affecting the time taken to reach target range in the majority of patients.
Clinical Pharmacology & Therapeutics (2011); 90 5, 701–706. doi:10.1038/clpt.2011.186
BACKGROUND: Canine T‐cell lymphoma (TCL) is conventionally considered an aggressive disease, but some forms are histologically and clinically indolent. CD4 TCL is reported to be the most common ...subtype of TCL. We assessed flow cytometric characteristics, histologic features when available, and clinical outcomes of CD4+ TCL to determine if flow cytometry can be used to subclassify this group of lymphomas. OBJECTIVE: To test the hypothesis that canine CD4+ T‐cell lymphoma (TCL) is a homogeneous group of lymphomas with an aggressive clinical course. ANIMALS: Sixty‐seven dogs diagnosed with CD4+ TCL by flow cytometry and treated at 1 of 3 oncology referral clinics. METHODS: Retrospective multivariable analysis of outcome in canine CD4+ TCL including patient characteristics, treatment, and flow cytometric features. RESULTS: The majority of CD4+ TCL were CD45+, expressed low class II MHC, and exhibited an aggressive clinical course independent of treatment regimen (median survival, 159 days). Histologically, CD4+ TCL were classified as lymphoblastic or peripheral T cell. Size of the neoplastic lymphocytes had a modest effect on both PFI and survival in this group. A small number of CD4+ TCL were CD45− and class II MHC high, and exhibited an apparently more indolent clinical course (median survival not yet reached). CONCLUSIONS AND CLINICAL IMPORTANCE: Although the majority of CD4+ TCL in dogs had uniform clinical and flow cytometric features and an aggressive clinical course, a subset had a unique immunophenotype that predicts significantly longer survival. This finding strengthens the utility of flow cytometry to aid in the stratification of canine lymphoma.
Recent studies have identified Clostridium difficile in food animals and retail meat, and concern has been raised about the potential for food to act as a source of C. difficile infection in humans. ...Previous studies of retail meat have relied on enrichment culture alone, thereby preventing any assessment of the level of contamination in meat. This study evaluated the prevalence of C. difficile contamination of retail ground beef and ground pork in Canada. Ground beef and ground pork were purchased from retail outlets in four Canadian provinces. Quantitative and enrichment culture was performed. Clostridium difficile was isolated from 28/230 (12%) samples overall: 14/115 (12%) ground beef samples and 14/115 (12%) ground pork samples (P = 1.0). For ground beef, 10/14 samples (71%) were positive by enrichment culture only. Of the 4 ground beef samples that were positive by direct culture, 20 spores/g were present in 2 while 120 and 240 spores/g were present in 1 each. For ground pork, 10/14 (71%) samples were positive by enrichment culture only. Of the 4 ground pork samples that were positive by direct culture, 20 spores/g were present in 3 while 60 spores/g were present in 1. Ribotype 078 predominated, consistent with some previous studies of C. difficile in food animals. Ribotype 027/North American pulsotype 1 was also identified in both retail beef and pork. This study has identified relatively common contamination of retail ground beef and pork with C. difficile spores; however, the levels of contamination were very low.
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