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A bacteriophage-based validation of a personal protective equipment doffing procedure to be used with high-consequence pathogens
- Brandon A. Berryhill, Kylie B. Burke, Andrew P. Smith, Jill S. Morgan, Jessica Tarabay, Josia Mamora, Jay B. Varkey, Joel M. Mumma, Colleen S. Kraft
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- Journal:
- Infection Control & Hospital Epidemiology , First View
- Published online by Cambridge University Press:
- 06 May 2024, pp. 1-7
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Objective:
To determine if the high-level personal protective equipment used in the treatment of high-consequence infectious diseases is effective at stopping the spread of pathogens to healthcare personnel (HCP) while doffing.
Background:Personal protective equipment (PPE) is fundamental to the safety of HCPs. HCPs treating patients with high-consequence infectious diseases use several layers of PPE, forming complex protective ensembles. With high-containment PPE, step-by-step procedures are often used for donning and doffing to minimize contamination risk to the HCP, but these procedures are rarely empirically validated and instead rely on following infection prevention best practices.
Methods:A doffing protocol video for a high-containment PPE ensemble was evaluated to determine potential contamination pathways. These potential pathways were tested using fluorescence and genetically marked bacteriophages.
Results:The experiments revealed existing protocols permit contamination pathways allowing for transmission of bacteriophages to HCPs. Updates to the doffing protocols were generated based on the discovered contamination pathways. This updated doffing protocol eliminated the movement of viable bacteriophages from the outside of the PPE to the skin of the HCP.
Conclusions:Our results illustrate the need for quantitative, scientific investigations of infection prevention practices, such as doffing PPE.
4 Initial Application of Constraint-Induced Cognitive Therapy to Long COVID Brain Fog
- Gitendra Uswatte, Edward Taub, Karlene Ball, Kristine Lokken, Shruti P Agnihotri, Victor W Mark, Amy Knight, Brandon Mitchell, Jason Blake, Staci McKay, Terika Miller, Elizabeth Pollard, Piper Hempfling, Morgan Smith, Rebekah Chatfield, Erin Stanley, Cliff Lynam, Kyli Blagburn, Brooke Carroll, Gary Cutter
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- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 598-599
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Objective:
Persistent brain fog is common in adults with Post-Acute Sequelae of SARS-CoV-2 infection (PASC), in whom it causes distress and in many cases interferes with performance of instrumental activities of daily living (IADL) and return-to-work. There are no interventions with rigorous evidence of efficacy for this new, often disabling condition. The purpose of this pilot is to evaluate the efficacy, on a preliminary basis, of a new intervention for this condition termed Constraint-Induced Cognitive therapy (CICT). CICT combines features of two established therapeutic approaches: cognitive speed of processing training (SOPT) developed by the laboratory of K. Ball and the Transfer Package and task-oriented training components of Constraint-Induced Movement therapy developed by the laboratory of E. Taub and G. Uswatte.
Participants and Methods:Participants were > 3 months after recovery from acute COVID symptoms and had substantial brain fog and impairment in IADL. Participants were randomized to CICT immediately or after a 3-month delay. CICT involved 36 hours of outpatient therapy distributed over 4-6 weeks. Sessions had three components: (a) videogamelike training designed to improve how quickly participants process sensory input (SOPT), (b) training on IADLs following shaping principles, and (c) a set of behavioral techniques designed to transfer gains from the treatment setting to daily life, i.e., the Transfer Package. The Transfer Package included (a) negotiating a behavioral contract with participants and one or more family members about the responsibilities of the participants, family members, and treatment team; (b) assigning homework during and after the treatment period; (c) monitoring participants’ out-of-session behavior; (d) supporting problem-solving by participants and family members about barriers to performance of IADL; and (e) making follow-up phone calls. IADL performance, brain fog severity, and cognitive impairment were assessed using validated, trans-diagnostic measures before and after treatment and three months afterwards in the immediate-CICT group and on parallel occasions in the delayed-CICT group (aka waitlist controls).
Results:To date, five were enrolled in the immediate-CICT group; four were enrolled in the wait-list group. All had mild cognitive impairment, except for one with moderate impairment in the immediate-CICT group. Immediate-CICT participants, on average, had large reductions in brain fog severity on the Mental Clutter Scale (MCS, range = 0 to 10 points, mean change = -3.7, SD = 2.0); wait-list participants had small increases (mean change = 1.0, SD = 1.4). Notably, all five in the immediate-CICT group had clinically meaningful improvements (i.e., changes > 2 points) in performance of IADL outside the treatment setting as measured by the Canadian Occupational Performance Measure (COPM) Performance scale; only one did in the wait-list group. The advantage for the immediate-CICT group was very large on both the MCS and COPM (d’s = 1.7, p’s < .05). In follow-up, immediate-CICT group gains were retained or built-upon.
Conclusions:These preliminary findings warrant confirmation by a large-scale randomized controlled trial. To date, CICT shows high promise as an efficacious therapy for brain fog due to PASC. CICT participants had large, meaningful improvements in IADL performance outside the treatment setting, in addition to large reductions in brain fog severity.
Using mobile phone data for epidemic response in low resource settings—A case study of COVID-19 in Malawi
- Dylan Green, Michael Moszczynski, Samer Asbah, Cassie Morgan, Brandon Klyn, Guillaume Foutry, Simon Ndira, Noah Selman, Maganizo Monawe, Andrew Likaka, Rachel Sibande, Tyler Smith
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- Journal:
- Data & Policy / Volume 3 / 2021
- Published online by Cambridge University Press:
- 09 August 2021, e19
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The COVID-19 global pandemic has had considerable health impact, including sub-Saharan Africa. In Malawi, a resource-limited setting in Africa, gaining access to data to inform the COVID-19 response is challenging. Information on adherence to physical distancing guidelines and reducing contacts are nonexistent, but critical to understanding and communicating risk, as well as allocating scarce resources. We present a case study which leverages aggregated call detail records into a daily data pipeline which summarize population density and mobility in an easy-to-use dashboard for public health officials and emergency operations. From March to April 2021, we have aggregated 6-billion calls and text messages and continue to process 12 million more daily. These data are summarized into reports which describe, quantify, and locate mass gatherings and travel between subdistricts. These reports are accessible via web dashboards for policymakers within the Ministry of Health and Emergency Operations Center to inform COVID-19 response efforts and resource allocation.
Simulation and flow physics of a shocked and reshocked high-energy-density mixing layer
- Jason D. Bender, Oleg Schilling, Kumar S. Raman, Robert A. Managan, Britton J. Olson, Sean R. Copeland, C. Leland Ellison, David J. Erskine, Channing M. Huntington, Brandon E. Morgan, Sabrina R. Nagel, Shon T. Prisbrey, Brian S. Pudliner, Philip A. Sterne, Christopher E. Wehrenberg, Ye Zhou
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- Journal:
- Journal of Fluid Mechanics / Volume 915 / 25 May 2021
- Published online by Cambridge University Press:
- 22 March 2021, A84
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This paper describes a computational investigation of multimode instability growth and multimaterial mixing induced by multiple shock waves in a high-energy-density (HED) environment, where pressures exceed 1 Mbar. The simulations are based on a series of experiments performed at the National Ignition Facility (NIF) and designed as an HED analogue of non-HED shock-tube studies of the Richtmyer–Meshkov instability and turbulent mixing. A three-dimensional computational modelling framework is presented. It treats many complications absent from canonical non-HED shock-tube flows, including distinct ion and free-electron internal energies, non-ideal equations of state, radiation transport and plasma-state mass diffusivities, viscosities and thermal conductivities. The simulations are tuned to the available NIF data, and traditional statistical quantities of turbulence are analysed. Integrated measures of turbulent kinetic energy and enstrophy both increase by over an order of magnitude due to reshock. Large contributions to enstrophy production during reshock are seen from both the baroclinic source and enstrophy–dilatation terms, highlighting the significance of fluid compressibility in the HED regime. Dimensional analysis reveals that Reynolds numbers and diffusive Péclet numbers in the HED flow are similar to those in a canonical non-HED analogue, but conductive Péclet numbers are much smaller in the HED flow due to efficient thermal conduction by free electrons. It is shown that the mechanism of electron thermal conduction significantly softens local spanwise gradients of both temperature and density, which causes a minor but non-negligible decrease in enstrophy production and small-scale mixing relative to a flow without this mechanism.
Origin and tectonic evolution of the NE basement of Oman: a window into the Neoproterozoic accretionary growth of India?
- BRANDON L. ALESSIO, MORGAN L. BLADES, GEORGE MURRAY, BENJAMIN THORPE, ALAN S. COLLINS, DAVID E. KELSEY, JOHN FODEN, JUSTIN PAYNE, SALAH AL-KHIRBASH, FRED JOURDAN
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- Journal:
- Geological Magazine / Volume 155 / Issue 5 / July 2018
- Published online by Cambridge University Press:
- 07 March 2017, pp. 1150-1174
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The Omani basement is located spatially distant from the dominantly juvenile Arabian–Nubian Shield (ANS) to its west, and its relationship to the amalgamation of those arc terranes has yet to be properly constrained. The Jebel Ja'alan (NE Oman) basement inlier provides an excellent opportunity to better understand the Neoproterozoic tectonic geography of Oman and its relationship to the ANS. To understand the origin of this basement inlier, we present new radiogenic isotopic data from igneous bodies in Jebel Ja'alan. U–Pb and 40Ar/39Ar geochronological data are used to constrain the timing of magmatism and metamorphism in the jebel. Positive εHf and εNd values indicate a juvenile origin for the igneous lithologies. Phase equilibria modelling is used to constrain the metamorphic conditions recorded by basement. Pressure–temperature (P–T) pseudosections show that basement schists followed a clockwise P–T path, reaching peak metamorphic conditions of c. 650–700°C at 4–7.5 kbar, corresponding to a thermal gradient of c. 90–160°C/kbar. From the calculated thermal gradient, in conjunction with collected trace-element data, we interpret that the Jebel Ja'alan basement formed in an arc environment. Geochronological data indicate that this juvenile arc formed during Tonian time and is older than basement further west in Oman. We argue that the difference in timing is related to westwards arc accretion and migration, which implies that the Omani basement represents its own tectonic domain separate to the ANS and may be the leading edge of the Neoproterozoic accretionary margin of India.
Contributor affiliations
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- By Frank Andrasik, Melissa R. Andrews, Ana Inés Ansaldo, Evangelos G. Antzoulatos, Lianhua Bai, Ellen Barrett, Linamara Battistella, Nicolas Bayle, Michael S. Beattie, Peter J. Beek, Serafin Beer, Heinrich Binder, Claire Bindschaedler, Sarah Blanton, Tasia Bobish, Michael L. Boninger, Joseph F. Bonner, Chadwick B. Boulay, Vanessa S. Boyce, Anna-Katharine Brem, Jacqueline C. Bresnahan, Floor E. Buma, Mary Bartlett Bunge, John H. Byrne, Jeffrey R. Capadona, Stefano F. Cappa, Diana D. Cardenas, Leeanne M. Carey, S. Thomas Carmichael, Glauco A. P. Caurin, Pablo Celnik, Kimberly M. Christian, Stephanie Clarke, Leonardo G. Cohen, Adriana B. Conforto, Rory A. Cooper, Rosemarie Cooper, Steven C. Cramer, Armin Curt, Mark D’Esposito, Matthew B. Dalva, Gavriel David, Brandon Delia, Wenbin Deng, Volker Dietz, Bruce H. Dobkin, Marco Domeniconi, Edith Durand, Tracey Vause Earland, Georg Ebersbach, Jonathan J. Evans, James W. Fawcett, Uri Feintuch, Toby A. Ferguson, Marie T. Filbin, Diasinou Fioravante, Itzhak Fischer, Agnes Floel, Herta Flor, Karim Fouad, Richard S. J. Frackowiak, Peter H. Gorman, Thomas W. Gould, Jean-Michel Gracies, Amparo Gutierrez, Kurt Haas, C.D. Hall, Hans-Peter Hartung, Zhigang He, Jordan Hecker, Susan J. Herdman, Seth Herman, Leigh R. Hochberg, Ahmet Höke, Fay B. Horak, Jared C. Horvath, Richard L. Huganir, Friedhelm C. Hummel, Beata Jarosiewicz, Frances E. Jensen, Michael Jöbges, Larry M. Jordan, Jon H. Kaas, Andres M. Kanner, Noomi Katz, Matthew S. Kayser, Annmarie Kelleher, Gerd Kempermann, Timothy E. Kennedy, Jürg Kesselring, Fary Khan, Rachel Kizony, Jeffery D. Kocsis, Boudewijn J. Kollen, Hubertus Köller, John W. Krakauer, Hermano I. Krebs, Gert Kwakkel, Bradley Lang, Catherine E. Lang, Helmar C. Lehmann, Angelo C. Lepore, Glenn S. Le Prell, Mindy F. Levin, Joel M. Levine, David A. Low, Marilyn MacKay-Lyons, Jeffrey D. Macklis, Margaret Mak, Francine Malouin, William C. Mann, Paul D. Marasco, Christopher J. Mathias, Laura McClure, Jan Mehrholz, Lorne M. Mendell, Robert H. Miller, Carol Milligan, Beth Mineo, Simon W. Moore, Jennifer Morgan, Charbel E-H. Moussa, Martin Munz, Randolph J. Nudo, Joseph J. Pancrazio, Theresa Pape, Alvaro Pascual-Leone, Kristin M. Pearson-Fuhrhop, P. Hunter Peckham, Tamara L. Pelleshi, Catherine Verrier Piersol, Thomas Platz, Marcus Pohl, Dejan B. Popović, Andrew M. Poulos, Maulik Purohit, Hui-Xin Qi, Debbie Rand, Mahendra S. Rao, Josef P. Rauschecker, Aimee Reiss, Carol L. Richards, Keith M. Robinson, Melvyn Roerdink, John C. Rosenbek, Serge Rossignol, Edward S. Ruthazer, Arash Sahraie, Krishnankutty Sathian, Marc H. Schieber, Brian J. Schmidt, Michael E. Selzer, Mijail D. Serruya, Himanshu Sharma, Michael Shifman, Jerry Silver, Thomas Sinkjær, George M. Smith, Young-Jin Son, Tim Spencer, John D. Steeves, Oswald Steward, Sheela Stuart, Austin J. Sumner, Chin Lik Tan, Robert W. Teasell, Gareth Thomas, Aiko K. Thompson, Richard F. Thompson, Wesley J. Thompson, Erika Timar, Ceri T. Trevethan, Christopher Trimby, Gary R. Turner, Mark H. Tuszynski, Erna A. van Niekerk, Ricardo Viana, Difei Wang, Anthony B. Ward, Nick S. Ward, Stephen G. Waxman, Patrice L. Weiss, Jörg Wissel, Steven L. Wolf, Jonathan R. Wolpaw, Sharon Wood-Dauphinee, Ross D. Zafonte, Binhai Zheng, Richard D. Zorowitz
- Edited by Michael Selzer, Stephanie Clarke, Leonardo Cohen, Gert Kwakkel, Robert Miller, Case Western Reserve University, Ohio
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- Textbook of Neural Repair and Rehabilitation
- Published online:
- 05 May 2014
- Print publication:
- 24 April 2014, pp ix-xvi
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Contributor affiliations
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- By Frank Andrasik, Melissa R. Andrews, Ana Inés Ansaldo, Evangelos G. Antzoulatos, Lianhua Bai, Ellen Barrett, Linamara Battistella, Nicolas Bayle, Michael S. Beattie, Peter J. Beek, Serafin Beer, Heinrich Binder, Claire Bindschaedler, Sarah Blanton, Tasia Bobish, Michael L. Boninger, Joseph F. Bonner, Chadwick B. Boulay, Vanessa S. Boyce, Anna-Katharine Brem, Jacqueline C. Bresnahan, Floor E. Buma, Mary Bartlett Bunge, John H. Byrne, Jeffrey R. Capadona, Stefano F. Cappa, Diana D. Cardenas, Leeanne M. Carey, S. Thomas Carmichael, Glauco A. P. Caurin, Pablo Celnik, Kimberly M. Christian, Stephanie Clarke, Leonardo G. Cohen, Adriana B. Conforto, Rory A. Cooper, Rosemarie Cooper, Steven C. Cramer, Armin Curt, Mark D’Esposito, Matthew B. Dalva, Gavriel David, Brandon Delia, Wenbin Deng, Volker Dietz, Bruce H. Dobkin, Marco Domeniconi, Edith Durand, Tracey Vause Earland, Georg Ebersbach, Jonathan J. Evans, James W. Fawcett, Uri Feintuch, Toby A. Ferguson, Marie T. Filbin, Diasinou Fioravante, Itzhak Fischer, Agnes Floel, Herta Flor, Karim Fouad, Richard S. J. Frackowiak, Peter H. Gorman, Thomas W. Gould, Jean-Michel Gracies, Amparo Gutierrez, Kurt Haas, C.D. Hall, Hans-Peter Hartung, Zhigang He, Jordan Hecker, Susan J. Herdman, Seth Herman, Leigh R. Hochberg, Ahmet Höke, Fay B. Horak, Jared C. Horvath, Richard L. Huganir, Friedhelm C. Hummel, Beata Jarosiewicz, Frances E. Jensen, Michael Jöbges, Larry M. Jordan, Jon H. Kaas, Andres M. Kanner, Noomi Katz, Matthew S. Kayser, Annmarie Kelleher, Gerd Kempermann, Timothy E. Kennedy, Jürg Kesselring, Fary Khan, Rachel Kizony, Jeffery D. Kocsis, Boudewijn J. Kollen, Hubertus Köller, John W. Krakauer, Hermano I. Krebs, Gert Kwakkel, Bradley Lang, Catherine E. Lang, Helmar C. Lehmann, Angelo C. Lepore, Glenn S. Le Prell, Mindy F. Levin, Joel M. Levine, David A. Low, Marilyn MacKay-Lyons, Jeffrey D. Macklis, Margaret Mak, Francine Malouin, William C. Mann, Paul D. Marasco, Christopher J. Mathias, Laura McClure, Jan Mehrholz, Lorne M. Mendell, Robert H. Miller, Carol Milligan, Beth Mineo, Simon W. Moore, Jennifer Morgan, Charbel E-H. Moussa, Martin Munz, Randolph J. Nudo, Joseph J. Pancrazio, Theresa Pape, Alvaro Pascual-Leone, Kristin M. Pearson-Fuhrhop, P. Hunter Peckham, Tamara L. Pelleshi, Catherine Verrier Piersol, Thomas Platz, Marcus Pohl, Dejan B. Popović, Andrew M. Poulos, Maulik Purohit, Hui-Xin Qi, Debbie Rand, Mahendra S. Rao, Josef P. Rauschecker, Aimee Reiss, Carol L. Richards, Keith M. Robinson, Melvyn Roerdink, John C. Rosenbek, Serge Rossignol, Edward S. Ruthazer, Arash Sahraie, Krishnankutty Sathian, Marc H. Schieber, Brian J. Schmidt, Michael E. Selzer, Mijail D. Serruya, Himanshu Sharma, Michael Shifman, Jerry Silver, Thomas Sinkjær, George M. Smith, Young-Jin Son, Tim Spencer, John D. Steeves, Oswald Steward, Sheela Stuart, Austin J. Sumner, Chin Lik Tan, Robert W. Teasell, Gareth Thomas, Aiko K. Thompson, Richard F. Thompson, Wesley J. Thompson, Erika Timar, Ceri T. Trevethan, Christopher Trimby, Gary R. Turner, Mark H. Tuszynski, Erna A. van Niekerk, Ricardo Viana, Difei Wang, Anthony B. Ward, Nick S. Ward, Stephen G. Waxman, Patrice L. Weiss, Jörg Wissel, Steven L. Wolf, Jonathan R. Wolpaw, Sharon Wood-Dauphinee, Ross D. Zafonte, Binhai Zheng, Richard D. Zorowitz
- Edited by Michael E. Selzer, Stephanie Clarke, Leonardo G. Cohen, Gert Kwakkel, Robert H. Miller, Case Western Reserve University, Ohio
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- Book:
- Textbook of Neural Repair and Rehabilitation
- Published online:
- 05 June 2014
- Print publication:
- 24 April 2014, pp ix-xvi
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Flow physics and RANS modelling of oblique shock/turbulent boundary layer interaction
- Brandon Morgan, K. Duraisamy, N. Nguyen, S. Kawai, S. K. Lele
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- Journal:
- Journal of Fluid Mechanics / Volume 729 / 25 August 2013
- Published online by Cambridge University Press:
- 19 July 2013, pp. 231-284
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Large-eddy simulation (LES) is utilized to investigate flow physics and lower-fidelity modelling assumptions in the simulation of an oblique shock impinging on a supersonic turbulent boundary layer (OSTBLI). A database of LES solutions is presented, covering a range of shock strengths and Reynolds numbers, that is utilized as a surrogate-truth model to explore three topics. First, detailed conservation budgets are extracted within the framework of parametric investigation to identify trends that might be used to mitigate statistical (aleatory) uncertainties in inflow conditions. It is found, for instance, that an increase in Reynolds number does not significantly affect length of separation. Additionally, it is found that variation in the shock-generating wedge angle has the effect of increasing the intensity of low-frequency oscillations and moving these motions towards longer time scales, even when scaled by interaction length. Next, utilizing the LES database, a detailed analysis is performed of several existing models describing the low-frequency unsteady motion of the OSTBLI system. Most significantly, it is observed that the length scale of streamwise coherent structures appears to be dependent on Reynolds number, and at the Reynolds number of the present simulations, these structures do not exist on time scales long enough to be the primary cause of low-frequency unsteadiness. Finally, modelling errors associated with turbulence closures using eddy-viscosity and stress-transport-based Reynolds-averaged Navier–Stokes (RANS) simulations are investigated. It is found that while the stress-transport models offer improved predictions, inadequacies in modelling the turbulence transport terms and the isotropic treatment of the dissipation is seen to limit their accuracy.
12 - Counseling Orphans and Vulnerable Children in Africa
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- By Gertie Pretorius, University of Johannesburg, South Africa, Brandon Morgan, University of Johannesburg, South Africa, Magen Mhaka-Mutepfa, University of Zimbabwe, Zimbabwe, Mary Shilalukey Ngoma, University of Zambia, Zambia, Thokozile Mayekiso, Nelson Mandela Metropolitan University, South Africa
- Edited by Elias Mpofu, University of Sydney
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- Book:
- Counseling People of African Ancestry
- Published online:
- 05 August 2011
- Print publication:
- 27 June 2011, pp 180-192
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Summary
OVERVIEW. Africa has the greatest proportion of orphans globally, with the HIV and AIDS pandemic one of the foremost reasons for this situation (UNAIDS/UNICEF/USAID, 2004). Despite the high numbers of orphans and other vulnerable children on the continent, state and federal governments repeatedly consider these children a last priority in social service provision. Furthermore, many services addressed toward these children attend to their basic needs and seldom address their emotional well-being. In this chapter, the psychological experiences of orphans and other vulnerable children are explored and counseling techniques that can be applied to this population group discussed. Examples of current programs in Africa are also presented.
LEARNING OBJECTIVES
By the end of the chapter, the reader should be able to:
Outline the challenges of defining orphans and vulnerable children (OVCs) in an African context.
Explain the importance of providing counseling to OVCs, especially within the framework of children's rights.
Evaluate the role of HIV and AIDS in the psychosocial experiences and well-being of OVCs.
Discuss appropriate counseling supports for OVCs.
Describe areas requiring further research in the counseling of OVCs.
INTRODUCTION
Statistics paint a poignant picture of the landscape of OVCs in Africa. According to the Children on the Brink Report (UNAIDS/UNICEF/USAID, 2004), in 2003, approximately 43 million orphans resided in sub-Saharan Africa. Of these children, roughly 11 million have become orphans as a result of the HIV and AIDS pandemic (UNAIDS, 2008).
Generation, identification and functional characterization of the nob4 mutation of Grm6 in the mouse
- LAWRENCE H. PINTO, MARTHA H. VITATERNA, KAZUHIRO SHIMOMURA, SANDRA M. SIEPKA, VICTORIA BALANNIK, ERIN L. MCDEARMON, CHIAKI OMURA, STEPHEN LUMAYAG, BRANDON M. INVERGO, BRETT GLAWE, DONALD R. CANTRELL, SAMSOON INAYAT, MARISSA A. OLVERA, KIRSTAN A. VESSEY, MAUREEN A. McCALL, DENNIS MADDOX, CATHERINE W. MORGANS, BRANDON YOUNG, MATHEW T. PLETCHER, ROBERT F. MULLINS, JOHN B. TROY, JOSEPH S. TAKAHASHI
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- Journal:
- Visual Neuroscience / Volume 24 / Issue 1 / January 2007
- Published online by Cambridge University Press:
- 12 April 2007, pp. 111-123
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We performed genome-wide chemical mutagenesis of C57BL/6J mice using N-ethyl-N-nitrosourea (ENU). Electroretinographic screening of the third generation offspring revealed two G3 individuals from one G1 family with a normal a-wave but lacking the b-wave that we named nob4. The mutation was transmitted with a recessive mode of inheritance and mapped to chromosome 11 in a region containing the Grm6 gene, which encodes a metabotropic glutamate receptor protein, mGluR6. Sequencing confirmed a single nucleotide substitution from T to C in the Grm6 gene. The mutation is predicted to result in substitution of Pro for Ser at position 185 within the extracellular, ligand-binding domain and oocytes expressing the homologous mutation in mGluR6 did not display robust glutamate-induced currents. Retinal mRNA levels for Grm6 were not significantly reduced, but no immunoreactivity for mGluR6 protein was found. Histological and fundus evaluations of nob4 showed normal retinal morphology. In contrast, the mutation has severe consequences for visual function. In nob4 mice, fewer retinal ganglion cells (RGCs) responded to the onset (ON) of a bright full field stimulus. When ON responses could be evoked, their onset was significantly delayed. Visual acuity and contrast sensitivity, measured with optomotor responses, were reduced under both photopic and scotopic conditions. This mutant will be useful because its phenotype is similar to that of human patients with congenital stationary night blindness and will provide a tool for understanding retinal circuitry and the role of ganglion cell encoding of visual information.