896 research outputs found
Momentum sensor - Electrostatic ballistic pendulum laboratory calibration unit Final report
Electrostatic ballistic pendulum momentum transducer for measuring particle impac
Multiple scattering in random mechanical systems and diffusion approximation
This paper is concerned with stochastic processes that model multiple (or
iterated) scattering in classical mechanical systems of billiard type, defined
below. From a given (deterministic) system of billiard type, a random process
with transition probabilities operator P is introduced by assuming that some of
the dynamical variables are random with prescribed probability distributions.
Of particular interest are systems with weak scattering, which are associated
to parametric families of operators P_h, depending on a geometric or mechanical
parameter h, that approaches the identity as h goes to 0. It is shown that (P_h
-I)/h converges for small h to a second order elliptic differential operator L
on compactly supported functions and that the Markov chain process associated
to P_h converges to a diffusion with infinitesimal generator L. Both P_h and L
are selfadjoint (densely) defined on the space L2(H,{\eta}) of
square-integrable functions over the (lower) half-space H in R^m, where {\eta}
is a stationary measure. This measure's density is either (post-collision)
Maxwell-Boltzmann distribution or Knudsen cosine law, and the random processes
with infinitesimal generator L respectively correspond to what we call MB
diffusion and (generalized) Legendre diffusion. Concrete examples of simple
mechanical systems are given and illustrated by numerically simulating the
random processes.Comment: 34 pages, 13 figure
A review of methods used to kill laboratory rodents: issues and opportunities
Rodents are the most widely used species for scientific purposes. A critical pre-requisite of their use, based on utilitarian ethical reasoning, is the provision of a humane death when necessary for scientific or welfare grounds. Focussing on the welfare challenges presented by current methods, we critically evaluate the literature, consider emerging methodologies that may have potential for refinement and highlight knowledge gaps for future research. The evidence supports the conclusion that scientists and laboratory personnel should seek to avoid killing laboratory rodents by exposing them to carbon dioxide (CO2), unless exploiting its high-throughput advantage. We suggest that stakeholders and policymakers should advocate for the removal of CO2 from existing guidelines, instead making its use conditionally acceptable with justification for additional rationale for its application. With regards to physical methods such as cervical dislocation, decapitation and concussion, major welfare concerns are based on potential inaccuracy in application and their susceptibility to high failure rates. There is a need for independent quality-controlled training programmes to facilitate optimal success rates and the development of specialist tools to improve outcomes and reliability. Furthermore, we highlight questions surrounding the inconsistent inclusion criteria and acceptability of physical methods in international regulation and/or guidance, demonstrating a lack of cohesion across countries and lack of a comprehensive ‘gold standard’ methodology. We encourage better review of new data and championing of open access scientific resources to advocate for best practice and enable significant changes to policy and legislation to improve the welfare of laboratory rodents at killing
Short-term heat stress results in diminution of bacterial symbionts but has little effect on life history in adult female citrus mealybugs
Mealybugs are sap-feeding insect pests that pose a serious threat to horticulture. The citrus mealybug, Planococcus citri (Risso) (Hemiptera: Pseudococcidae), like most other mealybug species, harbours two obligate maternally transmitted bacterial endosymbionts, which are essential for nutrient acquisition and host survival. These are ‘Candidatus Tremblaya princeps’, a member of the β-Proteobacteria, and ‘Candidatus Moranella endobia’, a member of the γ-Proteobacteria. The density of symbionts in the hosts is now understood to be dynamic, being influenced by the age and gender of the host and by environmental conditions during development. Here, we examine the impact of short-term heat stress treatment on the obligate symbionts and life-history parameters of P. citri, using qPCR to measure changes in symbiont density. Heat stress killed juveniles and adult males, and significantly reduced levels of ‘Ca. Moranella endobia’ and ‘Ca. Tremblaya princeps’ in adult females. However, adult females were resilient to this and it did not affect their fecundity or brood survival, although the sex ratio of their brood was slightly, but significantly, more female biased. Our results suggest that ‘Ca. Tremblaya princeps’ and ‘Ca. Moranella endobia’ are not as essential to the survival of adult mealybugs as they are to the survival of immature mealybugs and that sub-lethal heat treatment alone is unlikely to be effective as a disinfestation tactic
Persistent hypogammaglobulinemia in CVID secondary to protein losing enteropathy
Case Presentation: Patient is a 40 year old male with PMH of B cell Lymphoma s/p R-CHOP and radiation in remission, Common Variable Immunodeficiency (CVID) diagnosed prior to the hospital admission after IgG levels were found to be/dL (reference range of 700-1600 mg/dL) and recurrent Clostridium Difficile (C. Difficile) admitted to the ICU for left hip abscess and Acinetobacter pneumonia causing septic shock. Patient had a chronic history of septic arthritis of multiple joints, which had required recent antibiotics, and multiple surgeries resulting in persistent wounds causing serosanginous drainage from the surgical sites. Patient underwent incision and drainage the left hip for septic joint while in the ICU and was started on antibiotics. Upon admission, patient’s IgG level was 142 mg/dL and he received 30 g of IVIG infusion. Repeat IgG level one day following IVIG infusion was 565 mg/dL. Fourteen days after the infusion his IgG dropped down to 272 mg/dL. C3 was obtained and was mildly low (most likely due to current infection) and C4 was normal with normal complement activity. Flow cytometry showed normal number of B cells, normal total T cells (with low CD4+ and high CD8+) and normal NK cells. Patient was also found to have persistently low albumin levels, with most recent being 1.9 g/dL (reference range of 3.73-5.65 g/dL). Urinalysis did not demonstrate nephrotic range proteinuria. Due to recent diagnosis and infectious diarrhea due to recurrent C. Diff, it was thought patient was having protein losing enteropathy and loss of protein due to serosanginous drainage from chronic wounds. Due to overwhelming multifocal infections, per family wishes, patient was transitioned to comfort care and passed away peacefully.
Discussion: We present a case of a patient with known history of CVID who presented with septic shock and lack of normal IgG levels after recent IVIG infusion due to protein loosing enteropathy and protein loss from chronic wounds. CVID should be suspected in individuals with reduced levels of serum IgG in combination with low levels of IgA and/or IgM, reduced response to immunizations and an absence of any other immunodeficiency state [1]. Our patient was tested for an immunoglobulin deficiency as patient had multiple courses of failure of antibiotics for joint infections. This individual was diagnosed with CVID in 2019 as IgG/dL (L) with concurrent IgA/dL (L) and IgM\u3c 20 mg/dL (L). It was thought the immunoglobulin deficiency was a secondary hypogammaglobulinemia due to Rituximab [2], but there was strong clinical suspicion for true CVID given the severity of his infections. When this patient’s persistent hypogammaglobulinemia was discovered even after IgG infusions, reversible causes were looked into such as nephrotic syndrome. There have been notable cases of protein loosing enteropathies, such as Celiac Disease causing secondary hypogammaglobulinemia or exacerbating a primary disease process, such as CVID [3]. It is likely that patient’s acute drop in IgG 14 days after IgG infusions may have been due to protein loosing enteropathy secondary to recurrent C. difficile diarrhea and protein loss from significant serosanginous drainage from chronic wounds [4,5].
Conclusions: Secondary hypogammaglobulinemia may occur after Rituximab therapy. This case presentation demonstrates the utility in checking IgG levels prior to Rituximab therapy as there may be worsening of immunoglobulin levels post-Rituximab therapy. Acute protein loss can exacerbate CVID and cause overwhelming infections leading to septic shock. Therefore, it is important to determine the etiology of acute protein loss early on in the disease process with underlying CVID as reversible causes that are identified may improve patient outcomes or higher dosing of IVIG may be indicated in such settings where there is a rapid decline of immunoglobulin.https://scholarlycommons.henryford.com/merf2020caserpt/1086/thumbnail.jp
Disabling Travel: Quantifying the Harm of Inaccessible Hotels to Disabled People
During its 2023–2024 term, the U.S. Supreme Court will decide a case with significant implications for the future of the Americans with Disabilities Act (ADA). In Acheson Hotels v. Laufer, the Court will determine whether a civil rights “tester” plaintiff has Article III standing to sue a hotel for failing to provide information about the hotel’s accessibility online — in violation of Department of Justice (DOJ) regulations applying the ADA’s requirement of “reasonable modifications in policies, practices, or procedures” — when the plaintiff did not intend to book a hotel reservation. Plaintiff-Respondent Deborah Laufer has not only challenged the failure of Acheson Hotels to provide required information, but has also filed over 600 similar lawsuits, showcasing system-wide violations of the ADA’s “Reservation Rule.”
The Reservation Rule (“the Rule”), promulgated in 2010, requires hotels to make accessibility information available “through [their] reservations service[s] in enough detail to reasonably permit individuals with disabilities to assess independently whether a given hotel or guest room meets his or her accessibility needs.” The Rule also requires hotels to deliver accessible rooms in the same manner and during the same hours as inaccessible rooms, to hold accessible rooms for individuals with disabilities, and to guarantee that an accessible room reservation is held for the reserving customer. Among the motivations for the Rule’s passage were widespread complaints related to accessibility in the hotel reservation process. During the Rule’s notice and comment period, which began in 2008, industry representatives advocated for language that required hotels to treat disabled individuals in “a substantially similar manner” to nondisabled guests; the Department did not accept this suggested language, and the Rule instead requires hotels to treat disabled individuals “in the same manner” as nondisabled individuals. Hotels had an 18-month transition period to implement the changes. The American Society of Travel Agents, Inc. (at the time “the world’s largest association of professional travel agencies”) filed a comment with the DOJ in support of “parity in reservations policies” and explained that, to achieve that goal, hotels are best positioned to provide accurate accessibility information.
Hotels’ noncompliance with Title III of the ADA, and with the Reservation Rule in particular, is pervasive, and tester plaintiffs play a key role in enforcing the law. The ADA’s enforcement scheme depends in large part on private lawsuits to compensate for the limited resources of its designated enforcement agency, the DOJ. The burdens of filing suit and obtaining injunctive relief, however, are significant for the individuals on whom the ADA relies, the very same individuals who rely on the Act for the opportunity to, as Jacobus tenBroek famously put it, “live in the world.” Because damages are unavailable for violations of the Rule, suits for injunctive relief need to be filed before a problem arises: Injunctive relief is relatively useless for those who are denied accessibility information about public accommodations. Any injunction would take effect long after the disabled traveler needed the accessibility information. These obstacles undermine the affirmative duty that the Reservation Rule places on businesses to acknowledge and account for disabled individuals before those individuals need to book their reservations. Tester litigation helps to secure the services proposed by the Reservation Rule and to deliver on the regulation’s promise of equal efficiency, immediacy, and convenience
Effects of Art from the Heart on Nurse Satisfaction and Patient Well-Being
Introduction. Art programs have been shown to positively affect unit culture, quality of care, and nursing practices. Art interventions improve well-being, reduce stress, and enhance nurse-patient communication. Art from the Heart (AFTH) is an art program that provides art supplies, visual art, and patient About Me pages to patients, families and employees at University of Vermont Medical Center (UVMMC).Objective. Assess the efficacy of AFTH through nursing staff perceptions, understanding, and attitudes toward the program.Methods. Structured interviews were conducted on Baird 4, an adult inpatient ward, at UVMMC. A 19-question survey using Likert scales and short answer formats was administered to nursing staff. Questions assessed perceptions of effects of art on patient anxiety and pain, communication, and job satisfaction. Surveys were analyzed to extract major and minor themes.Results. Twenty-eight interviews were obtained and two major themes emerged: nurse satisfaction and patient well-being. Nursing staff satisfaction minor themes included improved productivity, promoting conversation, and creating a positive influence on the unit. Respondents reported that AFTH helped initiate conversations with patients (100% of respondents) and reduced workday stress (68%). The second major theme, patient well-being, included benefits to patients with dementia, providing comfort, and serving as an outlet or distraction. Utilizing AFTH improved perceived patient mood (100%), health (78.5%), and reduced patient anxiety (89.3%).Conclusions. AFTH provides positive benefits by reducing nursing staff stress and perceived patient anxiety; improving communication, perceived patient mood and health; and creating a sense of community. AFTH should be expanded to the entire 6 Community Agency: Burlington City Arts, Art from the Hearthttps://scholarworks.uvm.edu/comphp_gallery/1240/thumbnail.jp
Mitochondrial Homeostasis Mediates Lipotoxicity in the Failing Myocardium
Heart failure remains the most common cause of death in the industrialized world. In spite of new therapeutic interventions that are constantly being developed, it is still not possible to completely protect against heart failure development and progression. This shows how much more research is necessary to understand the underlying mechanisms of this process. In this review, we give a detailed overview of the contribution of impaired mitochondrial dynamics and energy homeostasis during heart failure progression. In particular, we focus on the regulation of fatty acid metabolism and the effects of fatty acid accumulation on mitochondrial structural and functional homeostasis
The Disability Cost Narrative: A Roundtable Discussion
The dominance of “cost narratives” in disability law and discourse warranted the inclusion of a scholarly roundtable discussion devoted to the topic. The transcription below captures this discussion among three disability legal scholars: Professors Elizabeth F. Emens, Kaaryn S. Gustafson, and Jasmine E. Harris
- …